JPH0792176A - Method and equipment for measuring speed - Google Patents

Abstract

PURPOSE:To provide a method and equipment for measuring the two-dimensional speed of an object easily. CONSTITUTION:An object 30 is provided with a pattern 40 of bright parts 41 and dark parts 42 of width (d) arranged at a constant interval. When the object 30 is deformed at a moving speed (v), the pattern 40 is also deformed at a moving speed (v) and an image having optical intensity variable periodically at a frequency omega=v/2d is formed. The light of the image enters a PROM element 16 through a focus lens system 18 and the like. The PROM element 16 is previously applied with an AC high bias voltage of frequency omega from an AC high voltage generator 15. Only the part being deformed at the speed (v) is recorded on the PROM element 16. The reading light enters the PROM element 16 through a laser light source 20 and a polarizer and the like and an optical image is eventually reproduced through an analyzer 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed measuring device and a speed measuring method, and more particularly to a PROM element (Pockles Read).
The present invention relates to a speed measuring device and a speed measuring method using an image information recording element such as an out optical modulator) or a spatial light modulating element.

[0002]

2. Description of the Related Art A velocity measuring method for measuring an object such as an elastic body or a fluid is one of the objects to be measured.
The method is roughly classified into a method of measuring only points and a method of measuring an object to be measured two-dimensionally.

As a method for measuring only one point, there is a method using a speed gun or the like. However, when measuring only one point, the velocity at that measurement point can be measured, but the velocity distribution of the entire measurement target cannot be measured.

Therefore, in order to analyze the detailed velocity distribution of the measuring object, it is necessary to measure the measuring object two-dimensionally. As a method of performing such two-dimensional measurement of speed, a method of two-dimensionally scanning a speed gun can be considered.

However, the method of scanning the speed gun two-dimensionally is a method of measuring each measuring point of the measuring object at high speed to obtain two-dimensional velocity information of the surface of the measuring object. This is a method in which measurement at one point is repeated. Therefore, if the resolution is improved, the measurement time becomes long, and if the measurement time is shortened, the resolution becomes poor.
There is a large limitation on the resolution and the measurement time, and it has been difficult to easily perform two-dimensional velocity measurement of the measurement target.

Therefore, an object of the present invention is to provide a velocity measuring device and a velocity measuring method which can easily perform two-dimensional velocity measurement of a measuring object.

[0007]

According to the present invention, an image information recording element that generates electric charges corresponding to the light intensity of writing light and holds the generated electric charges as polarization charges, and a light from a measurement target are provided. An image pickup unit which is incident on the image information recording element,
AC bias voltage applying means for applying an AC bias voltage of a desired frequency to the image information recording element, and generated in the image information recording element by light incident on the image information recording element from the measurement object. Of the electric charges, the electric charges generated by light from a specific region of the measurement target, the position of which changes at a speed corresponding to the frequency of the AC bias voltage, are selectively used as polarization electric charges to generate the image information. A velocity measuring device characterized by accumulating and holding in a recording element is obtained.

Further, according to the present invention, charges corresponding to the light intensity of the writing light are generated, the generated charges are held as polarization charges, and the reading light is modulated according to the held polarization charges. Spatial light modulator, imaging means for making light from a measurement object incident on the spatial light modulator, AC bias voltage applying means for applying an AC bias voltage of a desired frequency to the spatial light modulator, and the spatial light Light incident on the spatial light modulation element from the measurement target, which has a reading light incidence means for making the reading light incident on the modulation element and a reading light detection means for detecting the readout light emitted from the spatial light modulation element. Of the charges generated in the spatial light modulator by
In the spatial light modulator, charges generated by light from a certain region of the measurement target whose position changes at a speed corresponding to the frequency of the AC bias voltage are selectively polarized as polarization charges. The position of the measurement target that changes at a speed corresponding to the frequency of the AC bias voltage is detected by detecting read light that is accumulated and held, and is modulated and emitted according to the polarization charge. A velocity measuring device is obtained which is characterized by selectively detecting a region of.

The speed measuring device of the present invention may further comprise a DC bias voltage applying means capable of applying a DC bias voltage to the image information recording element or the spatial light modulation element.

Further, according to the present invention, an AC bias voltage having a desired frequency is applied to the image information recording element which generates charges corresponding to the light intensity of the writing light and holds the generated charges as polarization charges. , The light from the measurement target is incident on the image information recording element to which the AC bias voltage of the desired frequency is applied, and the light incident on the image information recording element from the measurement target causes the light to enter the image information recording element. Of the generated charges, the charges generated by light from a specific region of the measurement target, the position of which changes at a speed corresponding to the frequency of the AC bias voltage, are selectively used as polarization charges. A speed measuring method is obtained, which comprises a step of accumulating and holding in an image information recording element.

Further, according to the present invention, an AC bias voltage having a desired frequency is used to generate charges corresponding to the light intensity of the writing light, and the generated charges are held as polarization charges.
The read light is applied to the spatial light modulator that modulates the read light according to the polarization charge that is held, and the light from the measurement target is incident on the spatial light modulator to which the AC bias voltage of the desired frequency is applied. Of the charges generated in the spatial light modulation element by the light incident on the spatial light modulation element from the measurement target, in a certain region of the measurement target, at a speed corresponding to the frequency of the AC bias voltage. A step of selectively accumulating and holding electric charges generated by light from a region whose position changes in the spatial light modulation element as polarization charges; and causing the reading light to enter the spatial light modulation element to perform the spatial light modulation. The position of the measuring object is changed at a speed corresponding to the frequency of the AC bias voltage by detecting the read light which is modulated and emitted from the element according to the polarization charge. Speed measuring method characterized by having the steps of selectively detecting the specific area is obtained.

Further, according to the present invention, a step of providing a pattern having a periodic regularity on a measurement target, and an AC bias voltage of a desired frequency are generated by generating charges corresponding to the light intensity of the writing light. Is applied to the image information recording element that holds the electric charge as polarization charge, and the light from the measurement target is incident on the image information recording element to which the AC bias voltage of the desired frequency is applied, and the light is emitted from the measurement target. Of the charges generated in the image information recording element by the light incident on the image information recording element, the frequency of the AC bias voltage and the periodic regularity of the pattern in a specific region of the measurement target. A step of selectively accumulating and holding electric charges generated by light from a region whose position changes at a speed determined by the above as polarization charges in the image information recording element. Speed measuring method according to symptoms can be obtained.

Further, according to the present invention, a step of providing a pattern having a periodic regularity on the observation object, a step of flowing the observation object in the fluid to be measured, and writing an AC bias voltage of a desired frequency are written. A charge corresponding to the light intensity of light is generated, and the generated charge is applied to an image information recording element that holds it as polarization charge, and the light from the observation body and the fluid to be measured flowing through the observation body is applied to the desired light. The image information recording is performed by light that is incident on the image information recording element to which an AC bias voltage of the frequency is applied and is incident on the image information recording element from the observation object and the fluid to be measured flowing through the observation object. Of the charges generated in the element, in a specific region of the observation body, by the flow of the fluid to be measured,
At a rate determined by the frequency of the AC bias voltage and the periodic regularity of the pattern, charges generated by light from a region whose position changes are selectively accumulated in the image information recording element as polarization charges. And a step of holding the same, thereby obtaining a velocity measuring method.

Further, according to the present invention, an image in which a first AC bias voltage having a desired first frequency is used to generate charges corresponding to the light intensity of the writing light and the generated charges are held as polarization charges. The image information recording element is applied from the measurement object by applying light to the information recording element and making light from the measurement object incident on the image information recording element to which the first AC bias voltage of the desired first frequency is applied. Of the charges generated in the image information recording element by the light incident on the light source, the charge is generated at a speed corresponding to the first frequency of the first AC bias voltage in the first specific region of the measurement target. A step of selectively accumulating and retaining in the image information recording element the first charge generated by the light from the first region whose position changes as the first polarization charge, and a desired second frequency. And the first A second AC bias voltage having the second frequency different from the wave number is applied to the image information recording element, and light from the measurement target is applied with the second AC bias voltage having the desired second frequency. Of the charges generated in the image information recording element by the light incident on the image information recording element and incident on the image information recording element from the measurement object in the second specific region of the measurement object. Therefore, the second electric charge generated by the light from the second region whose position changes at a speed corresponding to the second frequency of the second AC bias voltage is selectively used as the second polarized charge. And a step of accumulating in the image information recording element and superposing the second polarized charge on the first polarized charge.

Further, according to the present invention, an AC bias voltage having a frequency characteristic including a plurality of different frequency components,
An electric charge corresponding to the light intensity of the writing light is generated, and the generated electric charge is applied to the image information recording element which holds it as polarization charge,
Of the charges generated in the image information recording element by the light incident on the image information recording element to which the AC bias voltage is applied, the light from the measurement object and entering the image information recording element from the measurement object. A plurality of regions of the measurement target, the electric charges generated by light from the plurality of regions whose respective positions change at speeds respectively corresponding to the plurality of different frequencies are selectively polarized as the image. A method for measuring velocity is provided, which has a step of accumulating and holding in an information recording element.

Further, according to the present invention, an AC bias voltage, the frequency of which changes with time in a predetermined frequency range, generates an electric charge corresponding to the light intensity of the writing light,
The generated charge is applied to an image information recording element that holds as polarization charge, and light from the measurement target is incident on the image information recording element to which the AC bias voltage is applied, and the image information recording element is measured from the measurement target. Of the electric charges generated in the image information recording element by the light incident on, the position of which changes at a speed corresponding to a frequency within the predetermined region in the specific region of the measurement target There is provided a speed measuring method including a step of selectively accumulating and retaining electric charges generated by light from the region as polarization electric charges in the image information recording element.

Further, according to the present invention, an AC bias voltage having a desired frequency is applied to the image information recording element which generates charges corresponding to the light intensity of the writing light and holds the generated charges as polarization charges. , The light from the measurement target is incident on the image information recording element to which the AC bias voltage of the desired frequency is applied, and the light incident on the image information recording element from the measurement target causes the light to enter the image information recording element. Of the generated charges, the first charges generated by the light from the specific region of the measurement target, the position of which changes at a speed corresponding to the frequency of the AC bias voltage, are selectively generated. A step of accumulating and holding a first polarization charge in the image information recording element, and applying a DC bias voltage to the image information recording element to direct light from the measurement object to the direct voltage. The second charge generated in the image information recording element by the light incident on the image information recording element to which the bias voltage is applied and entering the image information recording element from the measurement target is used as the second polarization charge. A step of accumulating and holding in the image information recording element,
A velocity measuring method is obtained, characterized in that the first polarized charge and the second polarized charge are overlapped and held in the image information recording element.

[0018]

A PROM element, which is a kind of spatial light modulator, is known as an image pickup element for an object. Here, the PROM element generates a charge corresponding to the light intensity of the writing light by the photoconductive effect, holds the generated charge as a polarization charge, and reads it according to the polarization charge held by the Pockels effect. An element that changes the polarization state of light. This PR
The OM element includes, for example, a Bi ₁₂ SiO ₂₀ single crystal plate, image information is written by utilizing the photoconductive effect, and image information is read by utilizing the Pockels effect.

That is, when writing image information,
Writing light is applied to the PROM element in a state where a bias voltage is applied, and polarization charges corresponding to image information are formed inside the element to perform image recording. Further, when reading recorded image information, linearly polarized light is projected onto a PROM element in a DC bias or non-biased state, and PR is performed.
Image information is read by utilizing the Pockels effect based on the polarization charge formed inside the OM element.

If this PROM element is used, various optical image information processing can be applied to the recorded image,
Further, since an incoherent light image can be converted into a coherent light image and an optical Fourier transform can be performed, various advantages can be achieved in image analysis.

When the writing light of intensity I (t) is vertically incident on the crystal plane of the PROM element or the like having a material having a photoconductive effect, the amount of charge Q accumulated on the crystal surface of the PROM element.
Is a current i flowing in the crystal in a direction perpendicular to the crystal plane.
It is expressed by the following equation by (t).

Q = ∫i (t) dt (1) This current i (t) is expressed by the product of the charge density q (t) of the carriers excited by the writing light and the moving speed. Since the speed is proportional to the applied electric field E (t), if the bias voltage applied to the PROM element is V (t), the current i
(T) is expressed by the following equation.

I (t) ∝q (t) E (t) ∝q (t) V (t) (2) Further, the charge density q (t) of the carrier is expressed by the following formula: It is proportional to the light intensity I (t).

Q (t) ∝I (t) (3) Therefore, the amount of charge Q accumulated on the crystal surface of the PROM element
Is expressed by the following equation.

Q∝∫I (t) V (t) dt (4) First, considering the case where a DC bias voltage V is applied to the PROM element, the bias voltage V is constant, and therefore the equation (4)
Is as follows: Q∝V∫I (t) dt (5) The amount of charge Q accumulated on the crystal surface of the PROM element is proportional only to the time integral of the light intensity I (t) of the writing light. However, it does not depend on the time change component of the writing light.

Therefore, when writing light is incident on the PROM element with a DC bias voltage applied to the PROM element,
All the image information of the measurement target is superimposed and recorded in the PROM element, and it is not possible to selectively record only the specific image information by the light whose intensity changes at a specific frequency. Conventionally, the bias voltage applied to the PROM element at the time of writing the image information is the DC bias voltage as described above. Therefore, in the conventional method of using the PROM element, the image information by light whose intensity changes at a specific frequency is used. Cannot be recorded selectively, and therefore, even if a measuring object moving with a certain velocity distribution is converted into light whose intensity changes in response to the velocity,
Even when it was incident on the PROM element, it was not possible to selectively obtain information on the specific speed of the measurement target.

However, when the writing light is incident on the PROM element in the state where the DC bias voltage is applied to the PROM element in this manner, all the image information of the measurement object is superimposed and recorded in the PROM element. Image information of the entire object is obtained.

Next, an AC bias voltage V is applied to the PROM element.
Consider the case where (t) = V ₀ cos 2πωt is applied.

The light intensity I (t) of the writing light is I (t) = I ₀
Assuming that (cos 2πω′t + 1), the amount of charge Q accumulated on the crystal surface of the PROM element is expressed by the following equation.

Q∝I ₀ V ₀ ∫ (cos 2πωt) (cos 2πω′t + 1) dt (6) Now, when the writing light is continuous light whose light intensity is constant over time, That is, considering the case of ω '= 0, the equation (6) is as follows.

Q∝2I ₀ V ₀ ∫cos 2πωtdt = (I ₀ V ₀ / πω) sin (2πωt) (7) As is apparent from the equations (7), when an AC bias voltage is applied to the PROM element, , The amount Q of electric charges accumulated on the crystal surface of the PROM element only slightly increases and decreases even if continuous light is irradiated. Therefore, when the AC bias voltage is applied to the PROM element, the PR
OM devices have little sensitivity to continuous light.

Next, when the frequency of the writing light and the frequency of the AC bias voltage applied to the PROM element match,
That is, when ω ′ = ω, the equation (6) is as follows.

Q∝I ₀ V ₀ ∫ (cos 2πωt) (cos 2πωt + 1) dt = I ₀ V ₀ ((t / 2) + (1 / 2πω) sin 2πωt + (1 / 8πω) sin 4πωt) (8) ) The first term of the equation (8) is the time t and the light intensity I of the writing light.
It is a term proportional to the product of the I ₀ component of (t) and the V ₀ component of the AC bias voltage V (t). Therefore, when an AC bias voltage is applied to the PROM element and the frequency of the writing light is equal to the frequency of the AC bias voltage, charges corresponding to the light intensity of the writing light are generated on the crystal surface of the PROM element. As a result, the PROM element is sensitive to light whose light intensity changes in synchronization with the AC bias voltage.

When an AC bias voltage is applied to the PROM element as described above, the PROM element is not sensitive to continuous light, but it is not sensitive to light whose intensity changes in synchronization with the AC bias voltage. Due to its sensitivity, when the light incident on the PROM element from the imaged object is composed of continuous light and light whose light intensity changes in synchronization with the AC bias voltage, the light is synchronized with the AC bias voltage. It is possible to selectively accumulate the charges generated by the light of which the intensity changes on the crystal surface of the PROM element. Therefore, image information synchronized with the AC bias voltage applied to the PROM element can be selectively recorded in the PROM element.

When a plurality of pieces of image information appearing in various cycles enter the PROM element, the image information synchronized with the applied AC bias voltage is selectively recorded in the PROM element. Therefore, the AC bias voltage of a specific frequency is PRO
By applying to the M element, only specific image information by light whose intensity changes at the same frequency as the AC bias voltage is selectively selected from a plurality of image information whose intensity changes at various frequencies. Can be recorded.

Therefore, when the light from the object to be measured is incident on the PROM element to which the AC bias voltage of the desired frequency is applied, among the charges generated in the PROM element by the light incident on the PROM element from the object to be measured. , A charge generated by light from a specific region of the measurement target whose position changes at a speed corresponding to the frequency of the AC bias voltage is selectively accumulated as polarization charge in the image information recording element. Can be held. Therefore,
It is possible to selectively record information regarding a region having a specific speed in the measurement target.

Further, the PROM element can process two-dimensional image information as it is in two dimensions without originally scanning the image.
Since it is a three-dimensional image pickup device, the two-dimensional velocity distribution of the measuring object can be easily measured.

Furthermore, the light from the measurement object is incident on the PROM element to which the AC bias voltage of the desired frequency is applied, and the speed corresponding to the frequency of the AC bias voltage in a specific region of the measurement object. After selectively writing the image information of the area whose position changes in the PROM element, the read light is incident on the PROM element, and the read light that is modulated and emitted by the PROM element according to the written image information is emitted. By performing the detection, it is possible to selectively detect a specific region of the measurement target whose position changes at a speed corresponding to the frequency of the applied AC bias voltage.

Further, not only the AC bias voltage but also the DC bias voltage can be applied to the PROM element, so that in addition to the image information of the area whose position changes at a certain speed, the entire measuring object is measured. Image information can also be recorded in a superimposed manner. Therefore, it is possible to accurately know the position of the region whose position changes at a certain speed with respect to the entire measurement target.

At this time, first, the AC bias voltage is set to PRO.
After applying to the M element to selectively record the image information of the area whose position changes at a certain speed in the PROM element, a DC bias voltage is applied to the PROM element to superimpose the image information of the entire measurement target. Alternatively, the AC bias voltage and the DC bias voltage may be applied to the PROM element at the same time to form a selective PROM element for the image information of the area whose position changes at a certain speed. And the image information of the entire measurement target may be recorded in the PROM element at the same time.

Further, a first AC bias voltage having a desired first frequency is applied to the PROM element, and image information of an area whose position changes at a speed corresponding to the first frequency is recorded in the PROM element. Then, a second AC bias voltage having a desired second frequency and a frequency different from the first frequency is applied to the PROM element, and its position is changed at a speed corresponding to the second frequency. By recording the second image information in which the
The first and second image information are recorded on the OM element in an overlapping manner. Therefore, by measuring the speed information of the measurement target by such a method, the speed information having different speed components can be recorded in an overlapping manner.

In this way, the frequency of the AC bias voltage applied to the PROM element is sequentially changed one after another, and an image is written each time, so that
Image information having a plurality of velocity components can be recorded in an overlapping manner.
However, if the AC bias voltage applied to the PROM element is not one having a single frequency component, such as a sine wave, but an AC bias voltage having a frequency characteristic that includes a plurality of different frequency components, a plurality of AC bias voltages are obtained. It is possible to simultaneously record a plurality of image information having different frequencies and the same frequency. Therefore, the speed information having a plurality of speed components can be measured by writing once.

Further, by changing the frequency of the AC bias voltage applied to the PROM element within a predetermined frequency range with time and recording an image, image information having a frequency component within this frequency range is obtained. All can be recorded. Therefore, it is possible to record all the speed information having the speed component corresponding to the frequency component within this frequency range by one writing. By using such a measuring method, it is possible to measure rough velocity information of an unknown measurement target.

If the measuring object for measuring the velocity information is light from the measuring object, the intensity of which changes at the frequency corresponding to the velocity, and if the measuring object is such a light from the measuring object. Is directly incident on the PROM element to which the AC bias voltage having the frequency corresponding to the speed is applied, the speed information of the measurement target can be measured. However, if the light from the measurement target that measures the velocity information is not the light whose intensity changes at the frequency corresponding to the speed of the measurement target, the light from the measurement target has the frequency corresponding to the speed. It must be light whose intensity changes.

In such a case, by providing a pattern having a periodic regularity on the object to be measured, when the position of the area on the object to be measured changes at a certain speed, the brightness of the area becomes periodic. Can be changed to.
The frequency at which the brightness changes is determined by the periodic regularity of this pattern and the speed of the area. Therefore, by providing a pattern having a periodic regularity on the measurement target in this way, the light from the measurement target can be light whose intensity changes at a frequency corresponding to its speed. As a result, if an AC bias voltage having a frequency determined by the speed of the object to be measured and the periodic regularity of this pattern is applied to the PROM element, the image information of the area whose position changes at this speed is selectively recorded in the PROM element. it can.

When the object to be measured is a fluid such as gas, liquid or powder, it is generally difficult to directly provide the fluid with a pattern having periodic regularity. In such a case, first, prepare an observation object provided with a pattern having a periodic regularity, let this observation object flow in a fluid, and determine the flow rate of this observation object and the periodic regularity of this pattern. By applying an AC bias voltage of a determined frequency to the PROM element, the observation object flowing at this speed can be selectively recorded in the PROM element, and as a result, fluid velocity information can be measured.

In the above, an image information recording element for generating charges corresponding to the light intensity of the writing light and holding the generated charges as polarization charges, and a charge corresponding to the light intensity of the writing light are generated, The action of the present invention will be described by taking as an example a PROM element having both a photoconductive effect and a Pockels effect as a spatial light modulator that holds generated charges as polarized charges and modulates read light according to the held polarized charges. However, GaAs single crystal, GaAs film, which is a material that has a photoconductive effect but not a Pockels effect,
Even when a hydrogenated amorphous silicon film, an amorphous silicon carbide film, an amorphous selenium film, or the like is used as the recording material for the image information recording element and the spatial light modulation element in the present invention, the PROM element in terms of recording the image information described above. It has the same effect as.

As the spatial light modulator used for recording / reproducing image information, charges corresponding to the light intensity of the writing light are generated, and the generated charges are held as polarization charges.
It is possible to use a spatial light modulator that changes the polarization state of the read light according to the polarization charge that is held.

As such a spatial light modulator, for example, the above-mentioned PROM element can be mentioned. As described above, the PROM element generates a charge corresponding to the light intensity of the writing light by the photoconductive effect, holds the generated charge as a polarization charge, and responds to the polarization charge held by the Pockels effect. Therefore, when a PROM element is used as a recording material of image information, the polarization state of the reading light can be changed by the PROM element itself, and the other reading element can be used. It is not necessary to additionally provide the above material in addition to the recording material.

Liquid crystal is used as a reading material for changing the polarization state of the reading light in accordance with the polarization charge.

When a liquid crystal, such as a twisted nematic liquid crystal (TNLC) whose polarization state changes depending on the applied voltage, is additionally provided in addition to the PROM element, an AC bias voltage applied to the PROM element during writing. The voltage value of can be reduced, and therefore, the structure of the AC bias voltage applying means can be simplified. The applied voltage required to obtain the same polarization change state is lower in the liquid crystal by about 2 digits or more than in the PROM element, so the voltage value of the AC bias voltage applied to the PROM element during writing is reduced, Even if the amount of electric charge accumulated and retained on the crystal surface of the PROM element is reduced, an electric field based on the electric charge is applied to the liquid crystal, so that the liquid crystal can change the polarization state of the read light as much as necessary. Because you can.

Further, a material having a photoconductive effect but not a Pockels effect, GaAs single crystal, GaAs
When a film, a hydrogenated amorphous silicon film, an amorphous silicon carbide film, an amorphous selenium film, or the like is used as a recording material for the image information recording element and the spatial light modulation element used in the present invention, a twisted material is used as a reading material. It is possible to use a liquid crystal such as a nematic liquid crystal (TNLC) whose polarization state of read light changes according to an applied voltage. Even in this case, since the necessary change state of the polarization of the reading light can be obtained with a small applied voltage, the value of the AC bias voltage applied to the recording material can be reduced, and thus the structure of the AC bias voltage applying means can be reduced. Can be simple. In this way, as a spatial light modulator,
In the case of using a spatial light modulator that generates charges corresponding to the light intensity of the writing light, holds the generated charges as polarization charges, and changes the polarization state of the reading light in accordance with the held polarization charges. Is preferably a device for injecting linearly polarized light using a polarizer or the like as the readout light incidence means for injecting readout light into the spatial light modulator used for image information reproduction. As the reading light detecting means for detecting the reading light emitted from the element, an apparatus having an element such as an analyzer capable of detecting the polarization state of light is preferably used.

Further, as a spatial light modulator used for recording / reproducing image information, charges corresponding to the light intensity of the writing light are generated, the generated charges are held as polarization charges, and the held polarization is maintained. It is possible to use a spatial light modulator that changes the transmittance of the read light according to the electric charge.

A liquid crystal is used as a reading material which changes the transmittance of the reading light according to the polarization charge. When a liquid crystal such as a polymer dispersed liquid crystal (PDLC) whose transmittance of read light changes according to an applied voltage is used, it is not necessary to use polarized light as read light, and thus a polarizer and an analyzer are unnecessary. Therefore, the structure of the image information reproducing system becomes simple.

A liquid crystal of which the transmittance of the reading light changes according to the applied voltage, such as this polymer dispersed liquid crystal (PDLC), is P
In addition to the ROM element, a GaAs single crystal, a GaAs film, a hydrogenated amorphous silicon film, an amorphous silicon carbide film, an amorphous selenium film, or the like, which is a material having a photoconductive effect but not a Pockels effect, may be provided. When used as a recording material for the image information recording element and the spatial light modulation element in the above, it may be used as a reading material.

Next, the writing time T _W of the image information will be examined. When the frequency of the image information matches the frequency of the AC bias voltage, the writing time T _W can be set arbitrarily.

On the other hand, when there is a deviation between the frequency ω'of the image information and the frequency ω of the AC bias voltage, the writing time T
_The problem is how to set _W.

Consider the case of ω ≠ ω 'in the equation (6).

Q∝I ₀ V ₀ ∫ (cos 2πωt + cos 2πωt · cos 2πω′t) dt = I ₀ V ₀ ((1 / 2πω) sin 2πωt + (1 / 2π (ω + ω ′)) sin 2π (ω + ω ′) t + (1 / 2π (ω−ω ′)) sin 2π (ω−ω ′) t) (9) In the equation (9), the third term is slower than other terms when ω to ω ′. It varies and the amplitude is large. Therefore, if the writing of the image information is completed faster than the period of the third term, the image information can be recorded. In this case, if the writing time T _W is set so as to satisfy the following expression, the PROM element has sensitivity.

(Ω-ω ') <1 / T _W (10)

[0061]

Embodiments of the present invention will now be described with reference to the accompanying drawings.

First, a PROM element used as an image information recording element or a spatial light modulation element in the velocity measuring device and velocity measuring method of the present invention will be described.

FIG. 16 shows P used in the embodiment of the present invention.
FIG. 3 is a cross-sectional view illustrating a ROM element.

The insulating layers 3 made of quartz glass are formed on both sides of the charge generation holding layer 4 made of a single crystal of Bi ₁₂ SiO _20.
And 5 are provided, and the ITO (In
transparent electrodes 2 and 6 made of dium tin oxide),
Substrate glasses 1 and 7 made of quartz glass are provided outside the transparent electrodes 2 and 6, respectively, to form a PROM element 16.

Image information writing light is incident on the PROM element 16 in the direction of arrow a. Since Bi ₁₂ SiO ₂₀ has sensitivity (photoconductivity) to electromagnetic waves having a shorter wavelength than blue light, light in the blue region, X-rays, or the like is used as writing light. When writing light enters, charge carriers (electrons and holes) corresponding to the writing light intensity are generated in the charge generation / holding layer 4 due to the photoconductive effect. When a bias voltage is applied between the transparent electrodes 2 and 6 via the terminals 8 and 9 in response to the incidence of writing light, the charge carriers generated by the photoconductive effect are generated in the electric field generated in the charge generation holding layer 4. Drifts in the charge generation / holding layer 4 and is polarized on the surface of the charge generation / holding layer 4. Since the insulating layers 3 and 5 are provided on both surfaces of the charge generation / holding layer 4, the polarized charge is held as polarization charges on both surfaces of the charge generation / holding layer 4.

In the present invention, between the transparent electrodes 2 and 6,
An AC bias voltage with a frequency corresponding to the desired recording speed is applied. This AC bias voltage may have various waveforms such as a sine wave, a triangular wave or a rectangular wave. As described above, when an AC bias voltage with a frequency corresponding to the recording speed is applied, the intensity of light from the region whose position changes at this velocity, that is, the charge proportional to the write light intensity, is generated as polarization charge. Since it is held on the surface of the holding layer 4, the amount of this polarization charge and its spatial distribution are recorded in the PROM element 16 as image information.

As described above, since the amount of polarization charge and its spatial distribution are recorded in the PROM element 16, this P
Image information having gradation is recorded in the ROM element 16.

Information once recorded can be erased by projecting blue light or an electromagnetic wave having a shorter wavelength than that onto the PROM element 16 with the transparent electrodes 2 and 6 short-circuited.

When a polarization charge is formed on the surface of the Bi ₁₂ SiO ₂₀ single crystal, an electric field having an intensity corresponding to the amount of the polarization charge is formed and birefringence occurs. Therefore, when reproducing the recorded image information, when the linearly polarized read light is incident on the PROM element 16, elliptically polarized light corresponding to the amount of polarization charge is emitted from the PROM element 16, so that if an analyzer is arranged in the subsequent stage, The amount of polarization charge can be measured by measuring the light intensity of the readout light emitted from the analyzer. Therefore, by projecting through the imaging optical system to the latter stage of the analyzer, P
The image information recorded in the ROM element 16 can be reproduced as an optical image. At this time, as reading light, Bi ₁₂ Si is used.
When light that does not produce a photoconductive effect on the O ₂₀ single crystal, for example, red light, is used, the distribution state of the polarization charge is not changed.
Image information can be played back.

When reproducing the image information, the PROM element 16
A DC bias may be applied between the transparent electrodes 2 and 6, or the transparent electrodes 2 and 6 may be short-circuited. When a DC bias is applied between the transparent electrodes 2 and 6, the electric field created by the polarized charges cancels the external electric field formed by the DC bias. Therefore, in the charge generation / holding layer 4, the electric field is weak in the portion irradiated with the writing light, and the electric field is strong in the non-irradiated portion, and the read image is a negative image of the written image information. When the transparent electrodes 2 and 6 are short-circuited, the electric field in the charge generation / holding layer 4 is only the electric field created by the polarization electric field. Therefore, the electric field becomes strong in the part irradiated with the writing light and becomes strong in the part not irradiated. Becomes weak. Therefore, the read image is a positive image of the written image information.

As a display device for the reproduced image information, for example, a reproduced image from the PROM element 16 can be picked up by a TV camera and displayed using a CRT, or it can be projected on a screen via a projection lens system. It can also be displayed. If necessary, an optical system for optical image processing such as optical Fourier transform may be provided, and the reproduced image from the PROM element 16 may be input to the optical system to perform appropriate image processing.

FIG. 17 is a sectional view for explaining a PROM element 56 with a liquid crystal used in an embodiment of the speed measuring device and the speed measuring method of the present invention.

The liquid crystal layer 50 is provided between the insulating layer 5 and the transparent electrode 6. When a material such as twisted nematic liquid crystal (TNLC) that changes the polarization state of read light in accordance with an applied voltage is used as the liquid crystal layer 50, the space between the transparent electrodes 2 and 6 of the PROM element with liquid crystal 56 at the time of writing is used. The voltage value of the AC bias voltage applied to the AC bias voltage can be reduced, so that the structure of the AC bias applying device for applying the AC bias voltage can be made simple and inexpensive. The applied voltage required to obtain the same change state of polarization is lower by about two digits in the liquid crystal than in the PROM element 16 shown in FIG.
The voltage value of the AC bias voltage applied between the transparent electrodes 2 and 6 of the OM element 56 is reduced to reduce the charge generation retention layer 4.
Even if the amount of electric charge accumulated and retained on the crystal surface of the liquid crystal is reduced, an electric field based on the electric charge is applied to the liquid crystal layer 50, so that the polarization state of the read light is changed by the liquid crystal layer 50 as necessary. Because you can.

Further, in the element having this structure, since the liquid crystal layer 50 modulates the read light, the charge generation / holding layer 4 can be made of a material having a photoconductive effect and no Pockels effect. . Therefore, in addition to the Bi ₁₂ SiO ₂₀ single crystal, a GaAs single crystal, a GaAs film, a hydrogenated amorphous silicon film, an amorphous silicon carbide film, an amorphous selenium film or the like can be applied.

As the liquid crystal, a polymer dispersion type liquid crystal (PDL) is used.
When a material whose transmittance of read light changes according to the applied voltage such as C) is used, it is not necessary to use polarized light for the read light, so that a polarizer and an analyzer are not required, and a vibration measuring device is used. The configuration will be simple.

Further, as shown in FIG. 18, a liquid crystal-attached P in which a reflective layer 51 is provided between the liquid crystal layer 50 and the charge generation / holding layer 4.
ROM element 56 'can also be used. As the reflective layer 51, for example, a laminated film of TiO ₂ and SiO ₂ is used. Image information writing light is incident from the direction of arrow A to perform recording. The reading light is incident from the direction of arrow B, and is reflected by the reflection layer 51.
Is reflected, and light is emitted in the incident direction to reproduce the image information. With this element structure, the read light does not pass through the charge generation / holding layer 4, and therefore, it is an advantage that the polarization charge distribution is not changed even if the wavelength of the read light is arbitrarily selected.

If the liquid crystal layer 50 has a sufficiently high insulating property and polarization charges can be held on the surface of the charge generation holding layer 4 by the liquid crystal layer 50, one or both of the insulating layers 3 and 5 may not be provided.

Next, the PROM element 16 or the PROM element with liquid crystal 5 shown in FIGS.
A speed measuring device and a speed measuring method using 6, 56 'will be described.

(First Embodiment) FIG. 1 is a schematic diagram for explaining a speed measuring device and a speed measuring method according to a first embodiment of the present invention, and FIG. It is a top view for explaining a measured object, and Drawing 3 is a top view for explaining a speed measurement result of this example.

In the present embodiment, the object of measurement is an elastic body, and the present invention is applied to the case where the one-way component of the deformation speed of each part when the elastic body is deformed is measured.

A signal having a frequency corresponding to the speed to be measured is generated by the oscillator 13, a high-voltage AC bias voltage synchronized with this signal is generated by the high-voltage AC voltage generator 15, and this high-voltage AC bias voltage is generated.
6 or liquid crystal-equipped PROM elements 56, 56 '.

The light from the elastic object to be measured 30 passes through the shutter 17, the imaging lens system 18 and the half mirror 19, and the PROM element 16 or the PROM element with liquid crystal 56.
It is incident on 56 '.

Since a high-voltage AC bias voltage having a frequency corresponding to the speed to be measured is applied to the PROM element 16 or the PROM elements with liquid crystal 56, 56 ', its position changes at the speed to be measured. Only P
ROM element 16 or PROM elements with liquid crystal 56, 56 '
Recorded in.

Further, the PROM element 16 or the liquid crystal-attached PR
After the high voltage AC bias voltage is applied to the OM elements 56 and 56 'to record the deformation information, the DC voltage generator 26 applies the DC bias voltage to the PROM element 16 or the PR with liquid crystal.
The light from the object to be measured 30 is applied to the OM elements 56 and 56 ', and in this state, is passed through the shutter 17, the imaging lens system 18 and the half mirror 19 to the PROM element 16 or the PROM elements with liquid crystal 56 and 56'. By being incident, the image information of the entire measured object 30 is also recorded in a superimposed manner. Therefore, it is possible to accurately know the position in the object to be measured 30 of the deformed portion that deforms at a specific speed.

As described above, first, the high-voltage AC bias voltage is applied to the PROM element 16 or the PROM elements with liquid crystal 56, 5.
6'is applied to record only the deformed portion which is deformed at the speed to be measured, and then the DC bias voltage is stored in the PROM.
The image information of the entire DUT 30 may be superimposed and recorded by being applied to the element 16 or the PROM elements with liquid crystal 56, 56 ', and the high voltage AC bias voltage and the DC bias voltage are applied simultaneously. Then, the image of the deformed portion deformed at the speed to be measured and the entire image information of the DUT 30 may be simultaneously recorded.

Next, the PROM element 16 or the PR with liquid crystal
A reproducing optical system for reproducing the images recorded on the OM elements 56 and 56 'will be described.

When the recorded image is reproduced, the shutter 17 is closed and the high voltage AC voltage generator 15 is turned off.

Reading light is generated from the laser light source 20.
The read light is PROM element 16 or P with liquid crystal.
Bi ₁₂ SiO used for ROM elements 56 and 56 '
₂₀ Light with a wavelength that does not cause photoconductivity in crystals, for example, wavelength 6
33 nm light is used. After that, the readout light generated from the laser light source 20 is linearly polarized by the polarizer 27. After that, the readout light passes through the reproduction light optical shutter 21,
Further, it becomes an expanded parallel light flux through a beam expander 25 composed of an expander lens and a collimator lens, and enters the PROM element 16 or the PROM elements with liquid crystal 56, 56 'through the half mirror 19.

The read light incident on the PROM element 16 or the PROM elements 56 and 56 'with liquid crystal is reflected by the PROM element 16
Alternatively, it becomes elliptically polarized light having an ellipticity according to the image information recorded in the PROM elements with liquid crystal 56, 56 ', and becomes P
ROM element 16 or PROM elements with liquid crystal 56, 56 '
Shoot out from. Therefore, the emitted read-out light is stored in the PROM.
By passing through the analyzer 22 arranged behind the element 16 or the PROM elements with liquid crystal 56, 56 ', the PRO
The image information recorded in the M element 16 or the PROM elements with liquid crystal 56, 56 'is reproduced as an optical image having a light intensity distribution corresponding to the image information. This optical image is T
An image is taken by the V camera 23 and displayed on the monitor 24.

According to this structure, the image information once recorded can be immediately reproduced, and a portable type speed measuring device can be realized.

At this time, the PROM element with liquid crystal 56,
When an element using a liquid crystal that changes the light transmittance such as PDLC is used as 56 ', the polarizer 27 and the analyzer 22 are used.
Is unnecessary.

In this embodiment, the light portion 41 and the dark portion 42, each of which has a width d, are equally spaced in one direction (y direction).
The striped pattern 40 arranged on the elastic body is provided on the elastic object 30 to be measured. When the DUT 30 is deformed, the pattern 40 is also deformed as shown in FIG. Assuming that the velocity component of the moving velocity v of the deformed portion of the object to be measured 30 in the direction perpendicular to the fringe (y direction in FIG. 2) is v _y , this deformation causes the frequency ω, ω = v _y / 2d, An image is formed in which the intensity of the light changes periodically.

Therefore, the PROM element 16 or the P with liquid crystal is used.
If the frequency ω of the high-voltage AC bias voltage applied to the ROM elements 56 and 56 ′ is ω = v _y / 2d, the PROM element 16 or the liquid crystal only for the deformed portion moving at the speed v _y in the y direction. The attached PROM elements 56 and 56 'have sensitivity, so that as shown in FIG. 3, a bright image can be obtained only in this modified portion.

(Second Embodiment) FIGS. 4, 5 and 6
[FIG. 8] is a plan view for explaining a pattern provided on a velocity measured object in the second example of the present invention.

The present embodiment is an application of the present invention to the case where the object to be measured is an elastic body and the two-direction component of the deformation speed of each part when the elastic body is deformed is measured.

The writing device for writing an image in the PROM element 16 or the PROM elements 56, 56 'with liquid crystal and the reproducing optical system for reproducing the written image are the same as those in the first embodiment. The operation is the same.

As shown in FIGS. 4, 5 and 6, a lattice-shaped pattern 40 is provided on the elastic object 30 to be measured. Bright part 4 of each grid
The width of 1 is d in both the x and y directions, and the width of the dark portion 42 is d in both the x and y directions.

When the measured object 30 is deformed, this pattern 40
Also transforms. When the DUT 30 is deformed in the x direction at a velocity v _x , this deformation forms an image in which the intensity of the light periodically changes at frequencies ω _x , ω _x = v _x / 2d.
Further, when the DUT 30 is deformed in the y direction at a velocity v _y ,
By this deformation, an image is formed in which the intensity of the light changes periodically at the frequencies ω _y and ω _y = v _y / 2d.

Therefore, the PROM element 16 or the P with liquid crystal is used.
If the frequency ω of the high-voltage AC bias voltage applied to the ROM elements 56 and 56 ′ is ω = v _x / 2d or ω = v _y / 2d, the velocity v _{x is} increased in the x direction or the y direction, respectively.
Or the PROM element 1 for the deformed portion deformed by v _y
6 or the PROM elements with liquid crystal 56, 56 'have sensitivity, so that a bright image can be obtained only in this modified portion.

(Third Embodiment) FIG. 7 is a plan view for explaining a pattern provided on a speed-measuring object in a third embodiment of the present invention, and FIG. 8 is a speed-measuring device of this embodiment. FIG. 10 is a plan view for explaining a measurement object, and FIG. 9 is a plan view for explaining a speed measurement result of the present embodiment.

In this embodiment, the measurement object is a rotating rigid body,
The present invention is applied when the angular velocity of the rotation is measured.

The writing device for writing an image in the PROM element 16 or the PROM elements 56, 56 'with liquid crystal and the reproducing optical system for reproducing the written image are the same as those in the first embodiment. The operation is the same.

As shown in FIG. 8, the object to be measured 30 has a plurality of rotating bodies 35, and each rotating body 35 rotates at an independent angular velocity v (φ).

In each of the rotating bodies 35, the bright portion 41 and the dark portion 42 are arranged radially from the center of rotation at an angle θ (de).
For each g), the patterns 40 alternately provided are provided. Rotating body 35 has angular velocity v (φ) (deg /
sec), the pattern 40 also has an angular velocity v (φ)
, And the rotation forms an image in which the light intensity changes periodically at the frequencies ω (φ), ω (φ) = v (φ) / θ.

Therefore, the PROM element 16 or the P with liquid crystal is used.
If the frequency ω of the high-voltage AC bias voltage applied to the ROM elements 56 and 56 ′ is ω = v (φ) / θ, only the PROM element 16 or the liquid crystal is rotated with respect to the rotating body rotating at the angular velocity v (φ). With PROM elements 56, 5
6'has sensitivity, and as shown in FIG. 9, therefore, only the rotating body 35 rotating at this angular velocity can obtain a bright image.

In this way, only the rotating body 35 that rotates at a specific angular velocity can be extracted from the plurality of rotating bodies 35. In addition, the PROM element 16 or the P with liquid crystal
The sensitivities of the ROM elements 56 and 56 'depend on the scalar quantity of the angular velocity of the rotating body 35, and do not depend on whether the rotating direction of the rotating body 35 is clockwise or counterclockwise.

(Fourth Embodiment) FIG. 10 shows a fourth embodiment of the present invention.
FIG. 3 is a plan view for explaining a speed measurement object of the example of FIG.

In this embodiment, the object of measurement is a plurality of spheres, cylinders and the like having the same shape, and the present invention is applied to the case where the moving speeds of these are measured.

The writing device for writing an image in the PROM element 16 or the PROM elements 56, 56 'with liquid crystal and the reproducing optical system for reproducing the written image are the same as those in the first embodiment. The operation is the same.

As shown in FIG. 10, a plurality of beer bottles 6 are provided.
1 is a passage 6 by a belt conveyor or the like (not shown).
Moving within 5. Since the width of the passage 65 is narrowed on the way, there are some places where the movement of the beer bottle 61 is delayed. The velocity distribution in such a case is measured.

When the beer bottle 61 is viewed from directly above, FIG.
As shown in, the beer bottles 61 are moving in contact with each other. When the radius of the beer bottle 61 is r, the distance between a certain crown 63 and the adjacent crown 63 is 2r.

When the beer bottle 61 moves at a velocity v whose absolute value is | v | = (v _x ² + v _y ² ) ^1/2 , the movement causes the frequencies ω _v and ω _v = v / 2r. , Forms an image in which the intensity of the light changes periodically.

Therefore, the PROM element 16 or the P with liquid crystal is used.
If the frequency ω of the high-voltage AC bias voltage applied to the ROM elements 56 and 56 ′ is ω = v / 2r, it has sensitivity to the crown 63 moving at the speed v, and only that portion can obtain a bright image. To be

When the measurement object itself gives an image whose intensity changes periodically as in this embodiment, the pattern 40 having a periodic regularity is obtained as in the first to third embodiments.
Does not have to be provided on the measurement target.

(Fifth Embodiment) FIGS. 11, 12, 13, 1
4 and 15 are plan views for explaining an observation object used in the fifth embodiment of the present invention.

The present embodiment is an embodiment of the present invention when the flow velocity is measured when the measurement target is a fluid such as gas, liquid or powder, and the fluid has a certain flow velocity distribution. It is applied.

The writing device for writing an image in the PROM element 16 or the PROM elements 56, 56 'with liquid crystal and the reproducing optical system for reproducing the written image are the same as those in the first embodiment, and the writing operation and the reading operation are performed. The operation is the same.

An observer 70 as shown in FIG. 11 is placed in the fluid.
Shed. The specific gravity and the like of the observation body 70 are set equal to that of the fluid so that the observation body 70 moves at the same speed as the fluid. The observation body 70 also moves according to the flow of the fluid, and the striped pattern 40 provided on the observation body 70 also moves.

Assuming that the moving speed of the observation body 70 in the direction perpendicular to the stripe is v, this deformation forms an image in which the intensity of the light periodically changes at the frequencies ω and ω = v / 2d. It

Therefore, the PROM element 16 or the P with liquid crystal is used.
If the frequency ω of the high-voltage AC bias voltage applied to the ROM elements 56 and 56 ′ is ω = v / 2d, the PROM element 16 or the PROM element with liquid crystal 56 only for the observation object 70 moving at this speed v. 5,
6'has sensitivity, so that a bright image can be obtained only in the portion where the observing body 70 flowing at this velocity v exists.

In this way, the velocity of the observation body 70 can be measured, and as a result, the flow velocity of the fluid in the portion where the observation body 70 is flowing can be measured. Further, if a plurality of observation objects 70 are put into the fluid, the flow velocity distribution of the fluid can be measured.

In FIG. 11, since the pattern 40 provided on the observation body 70 is striped, only the velocity of the component perpendicular to the strip can be measured. Therefore, as shown in FIG. 12, the bright portions 41 having concentric circles each having a radial width of d are shown.
The pattern 40 in which the dark areas 42 and the dark areas 42 are alternately arranged is used as the observation object 70.
If it is provided in, it is possible to measure in all directions.

Also, as shown in FIGS.
If a pattern 40 having a plurality of different stripe intervals is provided on the observation body 70, the PROM element 16 or the liquid crystal PROM element 5
When the frequency of the high-voltage AC bias voltage applied to 6, 56 'is ω, and the stripe interval d of the pattern 40 is captured brightly, the velocity v at that time can be v = 2dω. it can. Therefore, the PROM element 16
Alternatively, the speed can be measured without changing the frequency of the high-voltage AC bias voltage applied to the PROM elements with liquid crystal 56, 56 '.

The pattern 40 of FIG. 13 is a pattern in which striped patterns 401, 402, 403 and 404 having different stripe intervals are provided in a direction parallel to the stripes, and the pattern 40 of FIG. 14 is a stripe having different stripe intervals. The pattern is provided in a direction perpendicular to the stripes, and in FIG. 15, the stripe interval is continuously changed. The concentric pattern 40 of FIG. 12 and FIGS.
The observing body 70 may be provided with concentric patterns with unequal intervals, which are a combination of the patterns 4 and 15.

The present invention is not limited to the above-described embodiments, and various modifications and changes can be made. For example, although the transmissive PROM element is used in the above-described embodiments, it is also possible to use a reflective PROM element in which a reflective film of aluminum is formed.

If necessary, the recorded image may be subjected to optical image processing such as optical Fourier transform.

[0127]

The speed measuring device of the present invention generates an electric charge corresponding to the light intensity of the writing light and holds the generated electric charge as a polarization electric charge, and an image information recording element for measuring the light from the measurement object. Image information recording is performed by light incident on the image information recording element from an object to be measured, which has an image pickup means that is incident on the recording element and an AC bias voltage applying means that applies an AC bias voltage of a desired frequency to the image information recording element. Of the electric charges generated in the element, the electric charges generated by light from a certain region of the measurement target whose position changes at a speed corresponding to the frequency of the AC bias voltage are selectively imaged as polarized charges. Since the data is accumulated and held in the information recording element, the area of the measurement target whose position changes at a speed corresponding to the frequency of the AC bias voltage applied to the image information recording element is measured. It can be selectively recorded broadcast. As a result, the two-dimensional velocity measurement of the measurement target can be easily performed.

Further, the speed measuring device according to the present invention generates the electric charge corresponding to the light intensity of the writing light, holds the generated electric charge as the polarization electric charge, and reads the reading light in accordance with the polarization electric charge. A spatial light modulator for modulating, an imaging means for making light from a measurement object incident on the spatial light modulator, an AC bias voltage applying means for applying an AC bias voltage of a desired frequency to the spatial light modulator, and a spatial light modulator. The device includes a reading light incident unit that makes the reading light incident on the element, and a reading light detection unit that detects the reading light emitted from the spatial light modulation element, and the spatial light modulation is performed by the light that enters the spatial light modulation element from the measurement target. Of the charge generated in the device, the charge generated by light from a specific region of the measurement target whose position changes at a speed corresponding to the frequency of the AC bias voltage is selectively polarized. By accumulating and holding it as a load in the spatial light modulator, and detecting the read light that is modulated and emitted according to the polarization charge, the position of the measured object at a speed corresponding to the frequency of the AC bias voltage is detected. Since this specific area where the position changes is selectively detected, the information of the area whose position changes at a speed corresponding to the frequency of the AC bias voltage applied to the spatial light modulator is selectively recorded in the measurement target.・ Can be played. As a result, the two-dimensional velocity measurement of the measurement target can be easily performed.

Further, by further providing a DC bias voltage applying means capable of applying a DC bias voltage to the image information recording element or the spatial light modulation element, the position of the region whose position changes at a certain speed with respect to the entire measurement target is measured. You can know exactly.

Further, the speed measuring method of the present invention is applied to an image information recording element which generates an electric charge corresponding to the light intensity of writing light with an AC bias voltage of a desired frequency and holds the generated electric charge as a polarization electric charge. The light from the measurement target is applied to the image information recording element to which the AC bias voltage of the desired frequency is applied, and is generated in the image information recording element by the light incident on the image information recording element from the measurement target. In the image information recording element, the electric charge generated by light from a specific area of the measured object, the position of which changes at a speed corresponding to the frequency of the AC bias voltage, is selectively used as polarization charge. In the measurement target, the position of which changes at a speed corresponding to the frequency of the AC bias voltage applied to the image information recording element It can selectively record information. As a result, the two-dimensional velocity measurement of the measurement target can be easily performed.

Further, according to the velocity measuring method of the present invention, the AC bias voltage having a desired frequency is generated by generating the charge corresponding to the light intensity of the writing light, and the generated charge is held as the polarization charge. Applied to the spatial light modulator that modulates the readout light according to the polarization charge present, and the light from the measurement target enters the spatial light modulator to which the AC bias voltage of this desired frequency is applied. Light from the region of the charge generated in the spatial light modulator due to the light incident on the spatial light modulator, the position of which changes at a speed corresponding to the frequency of the AC bias voltage in a specific region to be measured. The process of selectively accumulating and retaining the charge generated as a polarization charge in the spatial light modulator, and the read light is incident on the spatial light modulator and modulated from the spatial light modulator according to the polarization charge. Of the read light emitted by the laser beam is detected to selectively detect a specific region of the measurement object whose position changes at a speed corresponding to the frequency of the AC bias voltage. Therefore, it is possible to selectively record / reproduce information in a region whose position changes at a speed corresponding to the frequency of the AC bias voltage applied to the spatial light modulation element in the measurement target. As a result, the two-dimensional velocity measurement of the measurement target can be easily performed.

Further, in the velocity measuring method of the present invention, a step of providing a pattern having a periodic regularity on an object to be measured, an AC bias voltage of a desired frequency is generated, and charges corresponding to the light intensity of the writing light are generated. , The generated electric charge is applied to the image information recording element that holds the polarization charge, and the light from the measurement target is incident on the image information recording element to which the AC bias voltage of the desired frequency is applied, and the image information is measured from the measurement target. Among the charges generated in the image information recording element by the light incident on the recording element, the position of the charge is a certain region to be measured at a speed determined by the frequency of the AC bias voltage and the periodic regularity of this pattern. Since there is a step of selectively accumulating and holding the charge generated by the light from the changing region in the image information recording element as polarization charge, the measurement target is the light from the measurement target. Not light intensity changes at a frequency corresponding to the speed of the measurement target, even such measurement target, it can be easily two-dimensional velocity measurement of the measurement object.

The velocity measuring method of the present invention comprises the steps of providing a pattern having a periodic regularity on the observation object, flowing the observation object in the fluid to be measured, and applying an AC bias voltage of a desired frequency, A charge corresponding to the light intensity of the writing light is generated, and the generated charge is applied to the image information recording element that holds it as polarization charge, and the light from the observation object and the fluid to be measured flowing through the observation object is applied to this desired light. The charge generated in the image information recording element by the light incident on the image information recording element to which the AC bias voltage of the frequency is applied and entering the image information recording element from the observation object and the fluid to be measured flowing through the observation object. Among them, in a certain region of the observation object, the light from the region whose position changes at a speed determined by the flow of the fluid to be measured is determined by the frequency of the alternating bias voltage and the periodic regularity of this pattern. Even if the measurement target is a fluid such as gas, liquid, powder, etc. Dimensional speed measurement can be easily performed.

Further, according to the velocity measuring method of the present invention, the first AC bias voltage of the desired first frequency is used to generate the electric charge corresponding to the light intensity of the writing light, and the generated electric charge is held as the polarization electric charge. To the image information recording element, and the light from the measurement object is incident on the image information recording element to which the first AC bias voltage of the desired first frequency is applied, and the light from the measurement object is changed to the image information recording element. Of the charges generated in the image information recording element by the incident light, the position of which changes in the first specific region of the measurement target at a speed corresponding to the first frequency of the first AC bias voltage. A step of selectively accumulating and retaining the first electric charge generated by the light from the first region in the image information recording element as the first polarized electric charge, and the desired second frequency and the first frequency. A second frequency different from The AC bias voltage, the image information recording element to apply a second light of the desired from the measurement object
Of the charges generated in the image information recording element by the light incident on the image information recording element to which the second AC bias voltage of the frequency is applied and incident on the image information recording element from the measurement object. The second charge selectively generated by the light from the second region of which the position changes at a speed corresponding to the second frequency of the second AC bias voltage in the second specific region The step of accumulating as polarization charge in the image information recording element and superposing the second polarization charge on the first polarization charge and recording the speed information having different speed components can do.

In the velocity measuring method of the present invention, an AC bias voltage having a frequency characteristic including a plurality of different frequency components is used to generate charges corresponding to the light intensity of the writing light, and the generated charges are polarized charges. Is applied as an image information recording element, and light from the measurement target is incident on the image information recording element to which this AC bias voltage is applied. Selectively polarize the charges generated by light from the multiple regions of the measurement target that change position at different speeds corresponding to multiple different frequencies. Since there is a step of accumulating and holding as an electric charge in the image information recording element, the speed information having a plurality of speed components can be measured by one writing. That.

Further, the speed measuring method of the present invention generates an electric charge corresponding to the light intensity of the writing light with an AC bias voltage whose frequency changes within a predetermined frequency range with time, and polarizes the generated electric charge. Image information recording is performed by applying light to the image information recording element, which is held as electric charge, and injecting light from the measurement target into the image information recording element to which this AC bias voltage has been applied, and entering the image information recording element from the measurement target Select the electric charge generated by the light from the specific area of the measurement target that changes its position at a speed corresponding to the frequency within this predetermined frequency range among the electric charges generated in the element Since there is a step of accumulating and holding as polarization charges in the image information recording element, it is possible to measure rough velocity information of an unknown measurement target.

Further, the speed measuring method of the present invention is applied to an image information recording element for generating an electric charge corresponding to the light intensity of writing light with an AC bias voltage of a desired frequency and holding the generated electric charge as a polarization electric charge. The light from the measurement target is applied to the image information recording element to which the AC bias voltage of the desired frequency is applied, and is generated in the image information recording element by the light entering the image information recording element from the measurement target. Of the electric charges, a first electric charge generated by light from a specific region of the measurement target, the position of which changes at a speed corresponding to the frequency of the AC bias voltage, is selectively used as the first electric charge.
A step of accumulating and holding as polarization charge in the image information recording element, and applying a DC bias voltage to the image information recording element and applying light from the measurement target to the image information recording element to which the DC bias voltage is applied. A step of accumulating and holding a second electric charge generated in the image information recording element by the light which is incident and is incident on the image information recording element from the measurement target as a second polarized charge in the image information recording element. Since the first polarization charge and the second polarization charge are superposed and held in the image information recording element, it is possible to accurately know the position of the region whose position changes at a certain speed with respect to the entire measurement target. it can.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining a speed measuring device and a speed measuring method according to a first embodiment of the present invention.

FIG. 2 is a plan view for explaining a velocity measured object according to the first embodiment of the present invention.

FIG. 3 is a plan view for explaining a speed measurement result of the first embodiment of the present invention.

FIG. 4 is a plan view for explaining a pattern provided on a velocity measured object according to a second embodiment of the present invention.

FIG. 5 is a plan view for explaining a pattern provided on a velocity measured object in the second embodiment of the present invention.

FIG. 6 is a plan view for explaining a pattern provided on a velocity measured object according to a second embodiment of the present invention.

FIG. 7 is a plan view for explaining a pattern provided on a speed measurement object according to a third embodiment of the present invention.

FIG. 8 is a plan view for explaining a velocity measured object according to a third embodiment of the present invention.

FIG. 9 is a plan view for explaining the speed measurement result of the third embodiment of the present invention.

FIG. 10 is a plan view for explaining a speed measurement target according to a fourth embodiment of the present invention.

FIG. 11 is a plan view for explaining an observation object used in a fifth embodiment of the present invention.

FIG. 12 is a plan view for explaining an observation object used in a fifth embodiment of the present invention.

FIG. 13 is a plan view for explaining an observation object used in a fifth embodiment of the present invention.

FIG. 14 is a plan view for explaining an observation object used in a fifth embodiment of the present invention.

FIG. 15 is a plan view for explaining an observation object used in a fifth embodiment of the present invention.

FIG. 16 is a cross-sectional view illustrating a PROM element used in the speed measuring device and the speed measuring method of the present invention.

FIG. 17 is a cross-sectional view for explaining a PROM element with a liquid crystal used in the speed measuring device and the speed measuring method of the present invention.

FIG. 18 is a sectional view for explaining another PROM element with a liquid crystal used in the speed measuring device and the speed measuring method of the present invention.

[Explanation of symbols]

1, 7 ... Substrate glass, 2, 6 ... Transparent electrodes, 3, 5 ... Insulating layer, 4 ... Charge generation holding layer, 8, 9 ... Terminal, 13 ... Oscillator, 15 ... High-voltage AC voltage generator, 16 ... PROM element ,
17 ... Shutter, 18 ... Imaging lens system, 19 ... Half mirror, 20 ... Laser light source, 21 ... Reproduction light optical shutter, 22 ... Analyzer, 23 ... TV camera, 24 ... Monitor,
25 ... Beam expander, 26 ... DC voltage generator,
27 ... Polarizer, 30 ... Object to be measured, 35 ... Rotating body, 40 ...
Pattern, 41 ... Bright part, 42 ... Dark part, 50 ... Liquid crystal layer, 51 ...
Reflective layer, 56, 56 '... PROM element with liquid crystal, 61 ... Beer bottle, 63 ... Crown, 65 ... Passage, 70 ... Observer, 4
01 ... striped pattern, 402 ... striped pattern, 403 ... striped pattern, 40
4 ... Striped pattern

Claims (11)

[Claims] 1. A charge corresponding to the intensity of writing light is generated,
An image information recording element that holds the generated charge as a polarization charge, an image pickup unit that causes light from a measurement target to enter the image information recording element, and an AC that applies an AC bias voltage of a desired frequency to the image information recording element Bias voltage applying means, and, among the charges generated in the image information recording element by the light incident on the image information recording element from the measurement object,
In the image information recording element, charges generated by light from a specific region of the measurement target, the position of which changes at a speed corresponding to the frequency of the AC bias voltage, are selectively used as polarization charges. A speed measuring device characterized by accumulating and holding. 2. A charge corresponding to the intensity of writing light is generated,
A spatial light modulation element that holds the generated charge as a polarization charge and modulates the readout light according to the held polarization charge; and an imaging means that makes light from the measurement target incident on the spatial light modulation element. AC bias voltage applying means for applying an AC bias voltage of the frequency to the spatial light modulation element, reading light incidence means for making read light incident on the spatial light modulation element, and reading light emitted from the spatial light modulation element. Read-out light detecting means for detecting, which is a specific region of the measurement target among charges generated in the spatial light modulation element by the light incident on the spatial light modulation device from the measurement target. Charges generated by light from a region whose position changes at a speed corresponding to the frequency of the AC bias voltage are selectively accumulated in the spatial light modulator as polarization charges. The specific region of the measurement object whose position changes at a speed corresponding to the frequency of the AC bias voltage by detecting read light that is emitted and is modulated according to the polarization charge. A velocity measuring device characterized by selectively detecting. 3. The speed measuring device according to claim 1, further comprising a DC bias voltage applying means capable of applying a DC bias voltage to the image information recording element or the spatial light modulating element. 4. An AC bias voltage having a desired frequency is applied to an image information recording element that generates electric charges corresponding to the light intensity of writing light and holds the generated electric charges as polarization charges, and light from the object to be measured. Is incident on the image information recording element to which an AC bias voltage of the desired frequency is applied, among the charges generated in the image information recording element by the light incident on the image information recording element from the measurement object,
In the image information recording element, charges generated by light from a specific region of the measurement target, the position of which changes at a speed corresponding to the frequency of the AC bias voltage, are selectively used as polarization charges. A method for measuring speed, comprising a step of accumulating and holding. 5. An AC bias voltage having a desired frequency is generated to generate a charge corresponding to the light intensity of the writing light, the generated charge is held as a polarization charge, and the reading light is stored according to the held polarization charge. Is applied to the spatial light modulation element that modulates the light, and the light from the measurement target is incident on the spatial light modulation element to which the AC bias voltage of the desired frequency is applied, and is incident on the spatial light modulation element from the measurement target. Of charges generated in the spatial light modulator by light, generated by light from a specific region of the measurement target, the position of which changes at a speed corresponding to the frequency of the AC bias voltage. A step of selectively accumulating electric charges as polarization charges in the spatial light modulation element and holding the same; reading light incident on the spatial light modulation element, and changing the polarization light from the spatial light modulation element according to the polarization charges. By detecting the read light that is modulated and emitted, the step of selectively detecting, in the measurement object, the specific region whose position changes at a speed corresponding to the frequency of the AC bias voltage. A method for measuring velocity, which comprises: 6. A step of providing a pattern having a periodic regularity on an object to be measured, an AC bias voltage having a desired frequency is used to generate charges corresponding to the light intensity of writing light, and the generated charges are used as polarization charges. The image information recording element to be held is applied, and the light from the measurement target is incident on the image information recording element to which the AC bias voltage of the desired frequency is applied, and the light is incident on the image information recording element from the measurement target. Of the charges generated in the image information recording element by the light
Selectively polarize charges generated by light from a specific region of the measurement target, the position of which changes at a speed determined by the frequency of the AC bias voltage and the periodic regularity of the pattern. And a step of accumulating and holding as an electric charge in the image information recording element, the speed measuring method. 7. A step of providing a pattern having a periodic regularity on an observation object, a step of flowing the observation object in a fluid to be measured, and an AC bias voltage of a desired frequency corresponding to the light intensity of writing light. Generated electric charge, and applying the generated electric charge to an image information recording element which holds the generated electric charge as a polarization electric charge, and applies light from the observation body and the fluid to be measured flowing through the observation body to an AC bias voltage of the desired frequency. Is incident on the image information recording element to which is applied, and charges generated in the image information recording element by the light incident on the image information recording element from the fluid to be measured flowing through the observation body and the observation body. Of the specific region of the observation object, the position thereof is determined by the flow of the fluid to be measured at a speed determined by the frequency of the AC bias voltage and the periodic regularity of the pattern. And a step of selectively accumulating and retaining, in the image information recording element, electric charges generated by light from a region in which the change occurs as polarization electric charges. 8. A first AC bias voltage having a desired first frequency is applied to an image information recording element which generates charges corresponding to the light intensity of writing light and holds the generated charges as polarization charges. The light from the measurement target is incident on the image information recording element to which the first AC bias voltage having the desired first frequency is applied, and the light is incident on the image information recording element from the measurement target by the light. Of the charges generated in the image information recording element,
A first specific region of the measurement target, the first region generated by light from the first region whose position changes at a speed corresponding to the first frequency of the first AC bias voltage; A step of selectively accumulating and retaining an electric charge in the image information recording element as a first polarized electric charge; a second frequency having a desired second frequency and different from the first frequency; An AC bias voltage of 2 is applied to the image information recording element, and light from the measurement target is applied to the second of the desired second frequencies.
Of the charges generated in the image information recording element by the light incident on the image information recording element to which the AC bias voltage of is applied, the incident from the measurement target to the image information recording element,
A second specific region of the measurement target, which is generated by light from the second region, the position of which changes at a speed corresponding to the second frequency of the second AC bias voltage. A step of selectively accumulating electric charges as second polarized charges in the image information recording element and holding the second polarized charges on the first polarized charges in an overlapping manner. Speed measurement method. 9. An image information recording element for generating an electric charge corresponding to the light intensity of writing light with an AC bias voltage having a frequency characteristic including a plurality of different frequency components and holding the generated electric charge as a polarization electric charge. The light from the measurement target is applied to the image information recording element to which the AC bias voltage is applied, and is generated in the image information recording element by the light entering the image information recording element from the measurement target. Out of the charge
The image information, which is generated by light from the plurality of regions of the plurality of regions to be measured, the positions of which change at respective speeds corresponding to the plurality of different frequencies, is selectively used as polarization charges. A method for measuring velocity, comprising the step of accumulating and holding the recording element. 10. An image information recording element which generates an electric charge corresponding to the light intensity of writing light with an AC bias voltage whose frequency changes in a predetermined frequency range with time, and holds the generated electric charge as a polarized electric charge. Is applied to the image information recording element to which the AC bias voltage is applied, and the light incident on the image information recording element from the measurement object generates the light in the image information recording element. Out of the charge
The image generated by the light from the specific region, which is a specific region of the measurement target and whose position changes at a speed corresponding to the frequency within the predetermined frequency range, is selectively used as the polarization charge. A method for measuring speed, comprising a step of accumulating and holding the information in an information recording element. 11. An AC bias voltage having a desired frequency is applied to an image information recording element that generates electric charges corresponding to the light intensity of writing light and holds the generated electric charges as polarization charges. Is incident on the image information recording element to which an AC bias voltage of the desired frequency is applied, among the charges generated in the image information recording element by the light incident on the image information recording element from the measurement object,
A first polarization generated by light from a specific region of the measurement target, the position of which changes at a speed corresponding to the frequency of the AC bias voltage, is selectively converted into a first polarization charge. And a step of accumulating and holding in the image information recording element, a DC bias voltage is applied to the image information recording element, and light from the measurement target is applied to the image information recording element The second charge generated in the image information recording element by the light incident on the image information recording element from the measurement target is accumulated and retained in the image information recording element as the second polarization charge. And a step of: (1) holding the first polarized charge and the second polarized charge in the image information recording element in an overlapping manner.