JPH10267631A - Optical measuring device - Google Patents

Abstract

(57) [Problem] To provide an optical measuring device capable of measuring required data in a short time. SOLUTION: In an optical measuring device using short coherent long light, a minute fluctuation mechanism 30 that modulates a reference light by slightly changing a reflection mirror 13, and a moving mechanism that controls the position of the minute fluctuation mechanism 30. 31 are provided. Then, when data collection (measurement) is performed, only the minute fluctuation mechanism 30 is activated (activated), and when the depth of the measurement point is changed, data collection is not performed and only the driving of the moving mechanism 31 is performed. Next, an optical measuring device is configured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical measuring device for measuring an optical characteristic of a sample, for example, an optical measuring device used for inspecting an internal structure of a biological sample.

[0002]

2. Description of the Related Art In recent years, various techniques capable of nondestructively inspecting the internal structure of a sample have been developed and have been used in various fields. As one of such techniques, optical coherence tomography (OCT) for obtaining a tomographic image or the like of a sample using light having a short coherent length is known.

[0003] The outline of OCT will be described below. The OCT uses an optical measurement device including a light source that generates light having a short coherent length (about ten and several μm), an interferometer including an optical multiplexer / demultiplexer, a movable reflection mirror, and a scanning system, and an analysis system.

[0004] Short coherent long light generated by a light source in the optical measuring apparatus is introduced into an optical multiplexer / demultiplexer constituting an interferometer, and is separated into measurement light and reference light. The measurement light passes through a scanning system for changing the position where the measurement light is introduced into the sample.
The measuring light introduced into the sample (for example, the eye) and reflected and scattered in the sample is returned to the optical multiplexer / demultiplexer via the scanning system. On the other hand, the reference light returns to the optical multiplexer / demultiplexer after being reflected by the reflecting mirror that is moving back and forth in the optical axis direction of the reference light in a distance range corresponding to the measurement range of the sample, and is reflected by the optical multiplexer / demultiplexer. ,
It is combined with the reflected light from the sample. In addition, as the movement pattern of the reflection mirror, usually, in order to facilitate the processing in the analysis system, after moving at a constant speed from the start point to the end point of the distance range, return to a high speed to the start point. A pattern in which there is a time zone in which the reflecting mirror moves at a constant speed (sawtooth-shaped or triangular-wave-shaped pattern) is used.

[0005] The analysis system is a process for determining the correspondence between the degree of intensity modulation applied to the light multiplexed by the optical multiplexer / demultiplexer and the position of the reflection mirror (the depth of the portion where the measurement light is introduced, (Process for obtaining optical characteristic data at several locations having different sizes) and store the results. When obtaining a cross-sectional image perpendicular to the optical axis of the measurement light, the measurement light is introduced to each position where measurement is required by the scanning system, and the analysis system
Calculation and storage of the optical characteristic data at each position are performed. Then, after acquiring the plurality of optical property data, the analysis system creates a cross-sectional image based on the optical property data,
indicate.

That is, in the OCT optical measurement device, a specific location is selected from among a large number of light beams that are simultaneously incident on the optical multiplexer / demultiplexer and are reflected and scattered at a plurality of locations at different depths in the sample. Short coherent long light is used to identify the reflected and scattered light. More specifically, as a result of being reflected and scattered at different depths, the light arriving at the optical multiplexer / demultiplexer at the same time is a short coherent light having a different separation time of the original measurement light at the optical multiplexer / demultiplexer. Since the light is long, among those lights, the light that interferes with the reference light from the reflection mirror side is the reflected light caused by the measurement light separated by the optical multiplexer / demultiplexer at the same time as the reference light, that is, Only the light reflected at the position where the optical path length of the measurement light is equal to the optical path length of the reference light is obtained. Since the frequency of the reference light is subject to Doppler shift due to the movement of the reference mirror,
The light multiplexed by the optical multiplexer / demultiplexer has a depth corresponding to the optical path length (correlated to the position of the reference mirror) of the reference light at that point in the sample, which corresponds to the magnitude of the measurement light component representing the optical characteristic. The light has been subjected to intensity modulation. For this reason, the analysis system analyzes the degree of intensity modulation of the light multiplexed by the optical multiplexer / demultiplexer in relation to the position of the reflection mirror, and thereby analyzes the optical characteristics at each depth of the portion where the measurement light is introduced. Can be requested. In OCT, a measurement based on such a principle is repeated at various points on a sample, and a two-dimensional image or a three-dimensional image of the sample is obtained.

[0007] References relating to the OCT technique include:
D. Huang et al., "Optical Coherence Tomography", Sci
1991, 254, pp. 1178-1181 and so on.

[0008]

As is clear from the above description, the spatial resolution of an OCT optical measuring device (hereinafter simply referred to as an optical measuring device) basically depends on the light used for measurement. Is determined by the coherent length of For this reason, the ultrasonic measurement technology (10 MH, which is a general measurement condition)
Spatial resolution at the time of z measurement: about 150 μm, laser scanning microscope technology (spatial resolution at the time of fundus part measurement: about 200 μm)
Measurement with higher spatial resolution (positional accuracy) is possible as compared with other measurement techniques such as m).

However, the conventional optical measuring apparatus employs a configuration in which the reflecting mirror is moved at a constant speed to acquire optical characteristic data on the sample to be measured, so that the position accuracy and the measurement of the optical characteristic data are measured. It has been difficult to improve both the precision and accuracy.

For example, the reflection mirror moves in a sawtooth shape, the moving speed is V, and the wavelength of the short coherent long light is λ.
Consider an optical measurement device that is In this case, the combined light will include a time-varying component having an angular frequency ω _D = 4πV / λ, but the measuring device generally has a dominant noise at a low frequency. This constant frequency noise is 1 / f noise due to the vibration of the circuit elements constituting the device or the device, and appears in a frequency region of about 10 kHz or less. Therefore, when configuring an optical measuring device as described above, the angular frequency omega _D is, so as not included in this region, it is necessary to move the reflecting mirror at a certain speed or more.

When the reflecting mirror is moved at a high speed in order to increase the angular frequency ω _D , the amount of change per unit time in the position where the reflected light is to be collected in the sample to be measured is naturally large. . At this time, if priority is given to the positional accuracy, the time for collecting the intensity of the interference light must be shortened. If there is a portion where the refractive index greatly changes in a portion scanned in such a short time, reflected light having sufficient intensity (good S / N) is incident on the optical multiplexer / demultiplexer. Therefore, accurate optical characteristic data is required. However, if this portion is a portion whose refractive index changes gradually, only weak (poor S / N) reflected light returns to the optical multiplexer / demultiplexer, so that only optical characteristic data with low accuracy is obtained. I can't. When the time for collecting data is extended to increase the S / N, data is collected from a wide range in the sample to be measured, as schematically shown in FIG. Therefore, the position resolution is deteriorated.

As described above, the conventional optical measuring device has been difficult to improve both the positional accuracy and the measuring accuracy of the optical characteristic data. Therefore, an object of the present invention is to improve the position accuracy and the measurement accuracy of optical property data.
An object of the present invention is to provide an optical measuring device that can be both excellent.

[0013]

In order to solve the above-mentioned problems, the present invention provides an optical multiplexing means for multiplexing incident light, a light generating means for generating light having a short coherent length, A light separating unit that separates the light generated by the light generating unit into a reference light and a measuring light, and a gap between an optical path length reaching the optical combining unit of the reference light separated by the light separating unit and a reference light reference optical path length. The reference light introducing means for modulating the reference light and introducing it to the optical multiplexing means while maintaining the state of being equal to or less than the value corresponding to the positional resolution required for the measurement, and the measuring light separated by the light separating means is measured. A measuring light introducing means for introducing the measuring light reflected and scattered by the measuring sample into the optical multiplexing means, and an electric signal having a level corresponding to the intensity of the light multiplexed by the optical multiplexing means, while being introduced into the target sample. Photoelectric conversion means for outputting And an electric signal output from the photoelectric conversion means,
An optical measurement device is configured by using the modulation frequency of the modulation given to the reference light by the reference light introduction unit and an acquisition unit that acquires optical characteristic data on one measurement point of the sample to be measured.

As described above, the optical measuring apparatus according to the present invention can determine the distance between the optical path length of the reference light and the reference light reference optical path length during the measurement at a certain measurement point to the positional resolution required for the measurement. A mechanism (reference light introducing means) for controlling the value to be equal to or less than the corresponding value is provided. For this reason, for example, when the reference light introducing means employs means for setting the distance to be equal to or less than the value corresponding to the coherent length of the short coherent long light generated by the light generating means, the position resolution determined by the coherent length of the light Thus, an optical measuring apparatus capable of measuring an arbitrary measurement point in a sample to be measured without deteriorating the measurement result can be obtained. Further, when a unit that sets the distance between the optical path length of the reference light and the reference light reference optical path length to a value equal to or more than the coherent length of the short coherent long light is adopted as the reference light introducing unit, the position corresponding to the distance is set. As a result, an optical measuring device capable of performing measurement at a resolution can be obtained.

The light generating means includes a super luminescent diode, a pulsed laser, a continuous wave laser for generating light with poor coherence, a light emitting diode, a laser operated with a current not exceeding a threshold value, and many others. Mode laser, laser-excited fluorescent light source, etc.
Originally, a light source that generates light with a short coherent length may be used, and a means that includes a light source that generates light with a long coherent length and a device that generates light with a short coherent length from the coherent light generated by the light source. May be used.

The time-varying pattern of the modulation applied to the reference light by the reference-light introducing means may be any. If the time-varying pattern is a sinusoidal pattern, a complicated electronic circuit may be used. Without using
Since the reference light introducing means can be realized, the optical measuring device can be formed at low cost. In this case, the DC component included in the electric signal output by the photoelectric conversion unit is set to “0” in consideration of the wavelength of the light generated by the light generation unit.
It is desirable to set the amplitude of the sinusoidal pattern so that If a sinusoidal pattern is set in this way, all of the signals representing the optical characteristics related to the sample to be measured included in the electric signal output by the photoelectric conversion means are AC signals. An optical measuring device that can measure optical characteristics with high accuracy can be obtained because it cannot be used for calculating optical characteristics (DC components cannot be used for calculating optical characteristics because they cannot be distinguished from DC components of noise). become.

The reference light introducing means includes a reflector for reflecting the reference light separated by the light separating means, a reflected reference light introducing means for introducing the reference light reflected by the reflector to the optical multiplexing means, By controlling the reflector moving mechanism for moving the position of the reflector and the reflector,
Means including a reflector moving mechanism control means for modulating the reference light, an optical fiber through which the reference light separated by the light separating means passes, a deformation mechanism for deforming the optical fiber, and controlling the deformation mechanism Thus, it is possible to use means including a deformation mechanism control means for modulating the reference light passing through the optical fiber.

When the optical measuring apparatus according to the present invention is formed, a means in which the modulation frequency of the reference light introducing means is given as data in advance may be adopted as the acquiring means. When using a means that can detect the modulation frequency from the outside, while adding detection means for detecting the modulation frequency, as acquisition means,
It is desirable to form the optical measurement device by employing a unit that uses the electric signal output by the photoelectric conversion unit and the modulation frequency detected by the detection unit. By employing such a configuration, an optical measuring device capable of performing measurement with higher accuracy can be obtained.

If a position changing means for changing the reference light reference optical path length or a position changing means for changing the reference light reference optical path length is added to the above-described configuration, the measuring means for obtaining the optical characteristic data by the obtaining means. The position of the point can be changed in the optical axis direction (depth direction) of the measurement light without changing the relative positional relationship between the sample to be measured and the optical measurement device. At this time, as the measuring light introducing means, the measuring light separated by the light separating means is applied to the sample to be measured such that the focal position thereof is a position corresponding to the reference light reference optical path length or the change amount of the measuring light reference optical path length. By using the introducing means, it is possible to obtain an optical measuring device in which the resolution in the direction perpendicular to the optical axis direction does not change even if the depth of the measurement point changes.

Further, if a measuring light introducing position changing means for changing the introducing position of the measuring light by the measuring light introducing means to the measuring object sample is added, the relative position between the measuring object sample and the optical measuring device can be increased. An optical measuring device that can change the measurement point in a direction orthogonal to the measurement light without changing the positional relationship can be obtained.

The measuring light introducing position changing means and the position control means may be manually operated, but each means may be electrically controllable, and one or more means may be obtained by the obtaining means. Introductory position information on measurement points,
Based on the position information stored in the storage unit that stores the position information including both or one of the optical axis direction position information in a form in which the order of use is known, the control of the measurement light introduction position changing unit and / or the position control unit is performed. Of course, the optical measuring device may be configured such that optical characteristic data regarding each measurement point whose position information is stored in the storage unit is obtained.

When the optical measuring apparatus is configured as described above, a storage means for storing measurement time information in a form in which the order of use is also understood is used as a storage means.
For each measurement point whose position information is stored in the storage means, during a time corresponding to the measurement time information associated with the measurement point, optical characteristic data is output using the electric signal output by the photoelectric conversion means. Can be obtained.

Further, the modulation frequency control as described above
The optical measuring device may be configured to be performed on the measurement light. That is, an optical multiplexing means for multiplexing incident light, a light generating means for generating light having a short coherent length, and a light for separating the light generated by the light generating means into reference light and measurement light Separating means, the reference light separated by the light separating means, a reference light introducing means for introducing the light into the optical multiplexing means, and introducing the measuring light separated by the light separating means to the sample to be measured, reflected by the sample to be measured, The means for introducing the scattered measurement light into the optical multiplexing means, wherein the distance between the optical path length from the light separation means of the measurement light to the optical multiplexing means and the measurement light reference optical path length is the positional resolution required for measurement. And a measuring light introducing unit that modulates the measuring light and introduces it into the optical multiplexing unit, and outputs an electric signal corresponding to the intensity of the light multiplexed by the optical multiplexing unit, while maintaining a state of being equal to or less than the value according to Photoelectric conversion means and the photoelectric conversion means; Means using a modulation frequency due to the electrical signal and measuring light introducing means is outputted, the sample to be measured, may constitute an optical measuring apparatus in combination obtaining means for obtaining optical characteristic data for one measurement point.

[0024]

Embodiments of the present invention will be specifically described below with reference to the drawings. <First Embodiment> FIG. 1 shows a configuration of an optical measuring apparatus according to a first embodiment. First, the function of each element constituting the optical measurement device according to the first embodiment will be described with reference to FIG.

The optical measuring apparatus according to the first embodiment is an apparatus for measuring an eye, and includes a light source 10 and a light source 15 as illustrated. The light source 10 is a light source that generates light used for measurement, and has a wavelength of approximately 830 nm and a coherent length of approximately 10 μm (hereinafter, referred to as short coherent long light). -It is configured using a luminescence diode (SLD). The light having a wavelength of 830 nm is used for the measurement because such light in the near infrared region does not damage the tissue of the eye to be measured, and
This is because the degree of penetration into the tissue is good. Further, the light source 10
The light source is a light source that can be turned on / off by a digital signal, and is connected to the computer 47 by a signal line (not shown). The light source 15 is a light source that generates visible light, and includes a semiconductor laser that generates light having a wavelength of 633 nm.

An optical multiplexer 17 is provided on the optical path 24 from which the light source 10 outputs short coherent long light. A total reflection mirror 16 is provided on an optical path 25 from which the light source 15 outputs visible light. The optical multiplexer 17 is an optical circuit using a half mirror that directs light incident from the optical path 24 side as it is (in the direction of the optical path 20) and guides light incident from below in the figure toward the optical path 20. , The light source 15 and the total reflection mirror 16 are arranged with respect to the optical multiplexer 17 so that the light from the light source 15 is guided onto the optical path 20.

That is, the light source 15, the total reflection mirror 16,
The optical multiplexer 17 is on the same optical path as the short coherent long light,
The light source 15 is an element for placing visible light (so-called aiming beam), and is driven when confirming that short coherent long light is irradiated to a target position of the measurement sample. Therefore, when light in the visible light region is used as the short coherent long light (when the object to be measured can irradiate such light), the optical measurement apparatus is configured without these elements. You can do it. Also, when using a CCD camera or the like for visualizing and observing the short coherent long light reflected and scattered in the sample to be measured, the optical measuring apparatus can be configured without providing these elements. .

An optical multiplexer / demultiplexer 11 is provided on the optical path 20. The optical multiplexer / demultiplexer 11 is also an optical circuit using a half mirror. The optical multiplexer / demultiplexer 11 separates the short coherent long light incident from the optical path 20 side and emits it on the optical paths 21 and 22. , Optical path 21 and optical path 2
The light incident from 2 is combined (combined) and emitted onto the optical path 23. Hereinafter, of the short coherent long lights split by the optical multiplexer / demultiplexer 11, light emitted on the optical path 21 is referred to as reference light, and light emitted on the optical path 22 is referred to as measurement light.
Light emitted on the optical path 23 is referred to as interference light.

The reference light output side of the optical multiplexer / demultiplexer 11 (optical path 21
In (upper), a lens system 12 is provided. At the position where the reference light is incident via the lens system 12, the reference light modulation mechanism 7 having the reflection mirror 13, the minute fluctuation mechanism 30, the moving mechanism 31, and the position sensor 50 as main components.
1 is provided.

Both the minute fluctuation mechanism 30 and the moving mechanism 31 change the position of the reflection mirror 13 while maintaining the state where the reflection surface is perpendicular to the optical axis of the reference light (the reflection mirror 13 (Translational movement with respect to the axis).

Specifically, the moving mechanism 31 is a mechanism for moving the member 35 to which the minute fluctuation mechanism 30 is fixed in a direction parallel to the optical axis 21 as indicated by an arrow 72. I have. The moving mechanism 31 includes a stepping motor,
The drive circuit in the moving mechanism 31 controls the stepping motor when receiving a predetermined control command from the computer 47 (to be described in detail later), thereby controlling the member 35. Move to the position specified in the command. Further, the moving mechanism 31 (drive circuit) has a function of outputting a signal indicating the current position of the member 35 (hereinafter, referred to as a center position signal). It is supplied to a focus position control mechanism 32 in the optical optical system 14.

The minute fluctuation mechanism 30 moves the reflection mirror 13
As shown by an arrow 73, the mechanism is for changing the direction in a direction parallel to the optical path 21. The mechanism is mainly composed of a piezo element to which the reflection mirror 13 is fixed and a driving circuit for the piezo element. The driving circuit in the minute fluctuation mechanism 30 includes:
At the time of measurement, the computer 47 supplies drive profile designation data that defines the correspondence between the control voltage (the amount of movement of the reflection mirror 13) to be supplied to the piezo element and time. The drive circuit in the minute fluctuation mechanism 30 according to the first embodiment includes the reflection mirror 1 as drive profile designation data.
3 is configured to receive three types of data that result in a sine wave, a triangular wave, and a sawtooth movement, and the drive circuit, when instructed to start operation by the computer 47, Control of the piezo element (position control of the reflection mirror 13) according to the drive profile designation data is started. At this time, the driving circuit
The piezo element is driven such that the center position of the vibration operation of (1) is the reference position (the position of the reflection mirror 13 when no voltage is applied to the piezo element).

The position sensor 50 is a sensor fixed to the member 35 and has a signal of a level corresponding to the distance between itself and the reflection mirror 13, that is, only a displacement of the reflection mirror 13 by the minute fluctuation mechanism 30. A signal (hereinafter, referred to as a displacement signal) is output. As shown, the displacement signal output by the position sensor 50 is supplied to a synchronous tuning detector 43 in the signal demodulation circuit 46.

An optical system for measuring light 14 is provided on an optical path 22 from which the measuring light is emitted. Optical system for measuring light 14
Are a lens system 33a for converting the measurement light into a parallel light, and a lens system 33b for converting the parallel light into light for focusing.
And a focus position control mechanism 32 that controls the position of the lens system 33b to change the position of the focus within the sample 1 to be measured. Although illustration is omitted, the measurement light introduction position (measurement site) is set in the measurement light optical system 14.
A measurement light scanning mechanism for changing two-dimensionally on a plane perpendicular to the optical path 22 is also provided.

The focus position control mechanism 32 moves the lens system 33b in the direction indicated by the arrow 74 so that the focus of the measurement light is located at a measurement point having a depth corresponding to the level of the center position signal from the movement mechanism 31. Control the position. That is, the focus position control mechanism 32 is configured to move the member 35 (the reflection mirror 1
The position of the lens system 33b is moved by a distance equal to the movement distance of 3). The measurement light scanning mechanism changes the position where measurement light is introduced into the measurement target sample 1 according to a control command given from the computer 47 (details will be described later).

On the optical path 23 side of the optical multiplexer / demultiplexer 11, a detector 40 for detecting the intensity of the interference light is provided.
In this embodiment, a detector using an avalanche photodiode (APD) is employed as the detector 40. An amplifier 41 and a signal demodulation circuit 46 are provided downstream of the detector 40. The amplifier 41 is a circuit that converts the current signal into a voltage signal and amplifies the voltage signal, and outputs a voltage signal corresponding to the level of the interference light incident on the detector 40.

The signal demodulation circuit 46 includes the band-pass filter 4
2, a synchronous tuning detection circuit 43, an integrator 44, and an A / D converter 45. The band-pass filter 42 is a filter that passes only a signal component in a predetermined frequency range, and outputs a signal obtained by removing a noise component (a frequency component that does not include information on a sample to be measured) from an output signal of the amplifier 41. The synchronous tuning detector 43 includes a band-pass filter 42.
, Synchronous detection is performed using the displacement signal from the position sensor 50, and the integrator 44 outputs a signal obtained by integrating the output of the synchronous tuning detector 43. A
When receiving a data sampling instruction from the computer 47, the / D converter 45 converts the signal from the integrator 33 into
The signal is converted into a digital signal and supplied to the computer 47.

The computer 47 stores a measurement sequence file creation program, a measurement program, a data processing program, and the like. The program for creating a measurement sequence file includes a program for interactively creating a measurement sequence file in which three-dimensional coordinate data relating to a point to be measured, measurement time designation data of each measurement point, and drive profile designation data are stored. Has become. The measurement program is a program that is started when the measurement is actually performed. When the measurement program is started, the computer 47 performs the measurement to be performed based on the data in the measurement sequence file specified by the operator. The positions of the points and the measurement order are recognized, and the optical characteristic data for each measurement point is measured. Then, a measurement data file storing the measurement results is created, and the measurement program ends. The data processing program is a program for outputting the data stored in the measurement data file to the monitor 48 or the printer 49 in the form of a two-dimensional image, a three-dimensional image, or raw data.

The overall operation of the optical measuring device according to the first embodiment will be described below. Prior to the actual measurement, the person (operator) who performs measurement using the optical measurement apparatus runs the measurement sequence file creation program, thereby obtaining three-dimensional coordinate data x, x, of a plurality of measurement points to be measured. y,
z (z is the coordinate of the measurement point in the depth direction, and x and y are
Creating several (at least one) measurement sequence files in which the measurement point coordinates on the plane perpendicular to the depth direction, the measurement time designation data t of each measurement point, and the drive profile designation data are stored; It is stored inside the computer 47. The computer 47 has a reflection mirror 1 that can be used as drive profile designation data.
Some standard data such as data whose contents are set so that the fluctuation width of the reference light path length due to the motion of 3 is equal to or less than the coherent length of the short coherent long light, and data whose fluctuation width is several hundred μm. Data is prepared, and the operator usually selects data (details will be described later) from those standard data according to the purpose of the measurement.
Create a measurement sequence file.

Then, the operator runs the measurement program when actually starting the measurement. The computer 47, which has started the operation according to the measurement program, first issues an initialization command to the moving mechanism 31 and the measuring light scanning mechanism in the measuring light optical system 14, thereby causing the moving mechanism 31, the measuring light scanning The state of the mechanism is set as a reference state. That is, by controlling the moving mechanism 31, both moving the position Z of the reflecting mirror 13 to the reference position z _0, by controlling the measurement light scanning mechanism, the position (X, Y) of the measurement light is introduced Reference position (x ₀ ,
y ₀ ).

Next, the computer 47 shifts to a state of waiting for input of a measurement sequence file name from the operator. When the measurement sequence file name is input, stored in the specified measurement sequence file, Nmax pieces of the coordinate data x _i, y _i, z _i and time information t
_i (i = 1 to Nmax) and drive profile designation data are read. Next, the computer 47 notifies the drive circuit in the minute fluctuation mechanism 30 of the drive profile designation data, and waits for an operation to instruct the start of measurement by the operator.

On the other hand, after running the measurement program, the operator inputs the name of the measurement sequence file to be used, and turns on the light source 15 to check the position to be irradiated with the measurement light. The apparatus adjusts the position of the subject's eye or the subject's eye) and the position of the optical measuring device so that the relative positional relationship between the sample 1 to be measured and the optical measuring device takes a predetermined positional relationship. I do.
When the adjustment of the positional relationship is completed, the light source 15 is turned off, and the computer 47 is instructed to start measurement.

Computer 47 instructed to start measurement
Operates according to the flowchart shown in FIG. That is,
The computer 47 first sets “1” to a variable i (step S101), and sets the light source 10 (light source for measurement) to:
An operation start (start of generation of short coherent long light) is instructed (step S102). Next, the computer 47
The measuring light measuring optical scanning mechanism of the optical system 14, the measurement light introducing position, the position (x _i, y _i) for instructing to change (step S103). Further, the computer 47
To the mobile mechanism 31, the position of the member 35 (the center position of the reflecting mirror 13), for instructing to move to a position z _i (step S104). Although not shown in the flowchart, the position (x _i , y _i ) did not need to be changed, that is, x _i = x _i-1 and y _i = y _i-1 . In this case, the computer 47 ends step S103 without issuing an instruction to the measurement light optical system 14 (proceeds to step S104). Similarly, when it is not necessary to change the position z _i (when z _i = z _i−1 ), the computer 47 ends step S104 without issuing an instruction to the moving mechanism 31.

After the end of step S104, the computer 47 waits for input of information indicating that the position change has been completed from the device that issued the instruction (step S10).
5) Do (if there is no device that has issued the instruction, end step S105 without waiting for information input).
Then, when the notification is received from the device that issued the instruction (either or both of the moving mechanism 31 and the optical system for measurement light 14) (step S <b>105; Y), the drive circuit in the minute fluctuation mechanism 30. Is instructed to start the operation (step S106). Then, a process of periodically acquiring data from the A / D converter 45 is started, and each acquired data is stored as data relating to the i-th measurement point (step S107). That is, the data from the A / D converter 45 is stored in association with the coordinates (x _i , y _i , z _i ). Then, after such processing is performed for the time t _i , the step S107 ends.

After the end of step S107, the computer 47 instructs the minute fluctuation mechanism 30 to stop the operation (step S108). Next, the content of the variable i is
By incrementing “1” (step S109), i ≦
If it is Nmax (step S110; Y), step S103 is performed to perform measurement at the next measurement point.
Is executed again. On the other hand, if i> Nmax (step S110; N), the computer 47
Instructs the measurement light source 10 to stop the operation (step S111), and ends the illustrated processing.

Here, referring to FIG. 3, x and y are x ₀ and y ₀ , respectively, as coordinate data of the “1” to “4” th measurement points in the measurement sequence file. only different data _{(however, z 0 <z 1 <z} 2 <z 3 <z 4)
However, the control of the computer 47 after the start of the measurement is instructed, as an example, in the case where the variation width of the reference light path length is set to a relatively small value is included as the drive profile designation data. The operation and a supplementary explanation of the operation performed by each unit as a result of the control operation will be described. The drive profile instruction data is data for moving the reflection mirror 16 in a sine wave shape, and it is assumed that the notification of the data to the minute fluctuation mechanism has already been completed. Further, the time information t is included in the measurement sequence file.
As ₁ ~t _4, the same data t _s is assumed to have been stored.

In such a situation, when the start of the measurement is instructed at time T ₁ , the computer 47 first instructs the moving mechanism 31 to move the center position of the reflection mirror 13 to the position z ₁ . . As a result, the moving mechanism 31
As shown in FIG. 3 (b), the center position is moved to the reflecting mirror 13 at a position z ₀ at the position z _1, the time T _2, the move is completed, notifies the computer 47. Further, when the the mobile is completed, the focal position control mechanism 32 which receives the center position signal moving mechanism 31 outputs, the beam waist positions of the measuring light, also will be moved to the coordinate z _1. The computer 47, having received the notification of the completion of the movement, instructs the drive circuit in the minute fluctuation mechanism 30 to start the operation, so that the drive circuit starts controlling the piezo element according to the given drive profile instruction data. I do. As a result, as shown in FIG. 3A, the reference mirror 13 starts to vibrate such that the displacement from the reference position changes sinusoidally around zero. Also, while the small fluctuation mechanism 30 is operating, drive mechanism 31, as is shown in FIG. 3 (b), maintains the center position coordinates of the reference mirror 13 in the same coordinate z _1. For this reason, FIG.
As is shown (c), the actual coordinates of the reflecting mirror 13 also changes around the coordinate z _1.

The reference light reflected by the reflecting mirror 13 vibrating in such a manner is subjected to modulation in accordance with the frequency of minute fluctuation of the reference mirror 13, and
In this case, the modulated reference light and the measurement light reflected and scattered at various points in the sample 1 to be measured are incident. Since the measurement light is a short coherent long light, the light that interferes with the reference light from the reflection mirror 13
Is only the measurement light reflected or scattered at a point at a depth corresponding to the actual coordinates of. For this reason, the intensity modulation component included in the light multiplexed by the optical multiplexer / demultiplexer 11 is
Only the optical characteristics of the portion corresponding to the optical path length of the reference light at that time are shown.

However, in the example shown in FIG. 3, since the moving speed of the reflection mirror 13 is continuously changing, the intensity modulation component includes many frequency components. However, in the optical measuring device of the first embodiment, the position sensor 5
Since the synchronous tuning detection using the output of 0 is performed, the output of the integrator 44 is the data indicating the optical characteristic of the measurement point as it is. For this reason, the computer 47 periodically collects the output of the integrator 44 during the time t _s and stores the collected data as data relating to the first measurement point. Then, the computer 47 sets the time T ₃ (=
At T ₂ + t _s ), the same control is repeated in order to complete data collection and perform measurement for the next measurement point.

As described above, in the optical measuring device according to the first embodiment, the center position of the reference mirror is fixed, and
The optical characteristics of the sample are measured in a state where the amount of change in the optical path length of the reference light is equal to or less than a specified value. For this reason,
If a measurement sequence file is created so that the amount of change in the optical path length of the reference light is about the coherent length of the short coherent long light or less, the resolution determined by the coherent length of the short coherent long light can be reduced. Thus, the measurement of the sample to be measured can be performed.

By creating a measurement sequence file in which the amount of change in the optical path length of the reference light is relatively large, a general measurement of the structure of the sample to be measured can be performed. According to this, the measurement relating to the sample to be measured can be completed by such a general measurement and the high-resolution measurement of only the portion where it is determined that the detailed measurement is necessary in the general measurement.

For example, when the human eye is a sample to be measured, the fine structure of the retina and the cornea is measured (ie,
Measurement with high spatial resolution) is often required.
However, since the vitreous body and the lens have an optically single-layer structure, it is sufficient to confirm that no turbid material exists inside these portions. The information required for this confirmation is only the average optical property data of the substances in several regions obtained by dividing the measurement target region (for example, the vitreous body). That is, if such optical characteristic data is obtained, the presence or absence of a turbid substance can be determined by determining whether each optical characteristic data is different from standard data (or optical characteristic data of an adjacent area). .

For this reason, when measuring the vitreous body or the like using the present optical measuring device, the measurement is performed at intervals of about several hundred μm, and the amount of change in the optical path length of the reference light is measured. If you set it according to the interval, in a short time,
The presence or absence of turbidity can be confirmed. If it is confirmed that a turbid substance exists, the change amount of the optical path length of the reference light is set to a small value, and the measurement is again performed on the area where the presence of the turbid substance is confirmed. Good.

As described above, the present optical measuring apparatus is configured so that the amount of change in the optical path length of the reference light can be specified.
By using the present optical measurement device, various measurements can be performed in a form according to the purpose of the measurement.

Further, since it is possible to set only a long measurement time for a portion where the reflected light intensity is weak, it is possible to accurately measure the optical characteristics of each part without causing the apparatus to perform unnecessary operations. . Further, when the depth of the measurement point changes (when the optical path length of the reference light changes), the position of the focal point of the measurement light is controlled according to the change, so that the depth of the measurement point is reduced. Even if it changes, the horizontal resolution is always equal. For this reason, a highly accurate two- or three-dimensional image can be obtained by using the present optical measurement device.

The circuit that can be used to extract the intensity modulation component from the interference light in the present optical measurement apparatus is not limited to the signal demodulation circuit 46 shown in FIG.
For example, the circuit shown in FIG. 4 can be employed for a portion corresponding to the signal demodulation circuit 46. That is, the synchronous tuning detector 43 and the integrator 44 are removed from the signal demodulation circuit 46, and the output of the band-pass filter 42 is output to the A / D converter 4
The circuit 46 ₂ which is directly connected to 5 can also be used. However, in this case, since the data representing the optical characteristics of the sample 1 to be measured is not output directly from the A / D converter 45, the measurement program is executed after the completion of the processing shown in FIG. In parallel), perform a frequency analysis (FFT, etc.) of the data collected for each measurement point,
It is a program that requires optical characteristic data. Naturally, the program is a program for performing a frequency analysis according to the drive profile instruction data.

For example, with respect to drive profile instruction data for changing the position of the reflection mirror 13 in a sinusoidal manner, a power spectrum represented by the following equation (1) is obtained, so that the angular frequencies ω _r , 2ω A routine for obtaining the size of a component such as _r by FFT or the like is executed. Note that in equation (1), J _n is n Bessel function, k is 2 [pi / lambda, L _a is a reflecting mirror 1
The amplitude of the vibration motion (micro vibration) of No. 3, ω _r is each frequency of the micro vibration, and t _M is the measurement time.

[0058]

(Equation 1)

Since the Bessel function J _n (x) is a function as shown in FIG. 5, when 2 kL _{a is set} to an arbitrary value, a component having _a coefficient J ₀ (2 kL _a ) in the power spectrum is obtained. That is, a DC component is included.
Since it is impossible to distinguish this DC component from the DC component included in the noise, the component having the coefficient J ₀ (2 kL _a ) cannot be used for calculating the optical characteristic value.
Therefore, sinusoidally, when vibrating the reflective mirror 13, to assume a J ₀ (2kL _a) is "0", by selecting 2kL _a, relative to the other of the angular frequency of the signal strength It is desirable to raise. For example, as in the optical measuring device of the first embodiment, as short coherent long light,
When light with a wavelength λ of 830 nm is used, J ₀ (2 kL
The value of 2kL _{a which a)} is "0", since it is approximately 2.405, L _a is approximately 158.9nm (= 2.405
× λ / 4π) is desirable to vibrate the reflection mirror. When the reflecting mirror is vibrated in this manner, the power spectrum is as shown in FIG.

Further, with respect to the drive profile instruction data for changing the position of the reflection mirror 13 in a triangular waveform,
The power spectrum shown in the following equation (2) and FIG. 7 is obtained. In the equation (2), k is 2π /
lambda, L _a is the amplitude of the triangular wave, T is the period of the triangular wave, f
_r is 1 / T.

[0061]

(Equation 2)

[0062] Thus, in the case of vibrating the reflective mirror 13 to the triangular waveform, since the power spectrum angular frequency 8kL _a f _r reaches a peak which is proportional to the moving speed of the reflection mirror 13 is obtained, the angular frequency The size of the component is FF
A routine to be determined by T or the like is executed. It should be noted that when such arithmetic processing is performed, the output of the position sensor 50 may be used (so that synchronous detection is performed).

Further, the reflecting mirror 13 is turned into a triangular wave or
In the case of vibrating only in a tooth shape, the signal demodulation circuit 46 is used instead.
Instead, the band-pass filter 42 shown in FIG._ThreeAnd rectification
Unit 75, integrator 44, logarithmic amplifier 76, and A / D converter 4
5 signal demodulation circuit 46 _ThreeCan also be adopted
You.

[0064] When configuring the signal demodulating circuit 46 _3, as a band-pass filter 42 _3, a bandpass filter 42
A filter having an extremely narrow pass band is used.
Then, the reflecting mirror 13 is vibrated at such a speed that the center wavelength of the pass band coincides with the frequency of the intensity modulation component included in the interference light. When the optical measurement device is operated under such conditions, a signal corresponding to the magnitude of the intensity modulation component included in the interference light is output from the rectifier 75. The integrator 44 outputs a signal obtained by integrating the signal, and the logarithmic amplifier 76 adjusts the dynamic range of the input signal and supplies the signal to the A / D converter 45. Therefore, the computer 47 can collect the measurement results for each measurement point only by storing the output of the A / D converter 45, as in the case where the signal demodulation circuit 36 is connected.

[0065] Further, when the reflecting mirror 13 constitutes an optical measuring device that oscillates sinusoidally may employ a signal demodulating circuit 46 ₄ shown in FIG. That is, the band-pass filter 42 _4A through 42 _4C, synchronous tuning detector 43 _A ~ 43 _C, by connected as shown, the angular frequency omega _r component contained in the intensity modulation component included in the interference light, the angular frequency A signal corresponding to the magnitude of the 2ω _r component and the magnitude of the angular frequency 3ω _r component is respectively output from the synchronous tuning detector 43 _A
To be output from ~ 43 _C. Then, in the subsequent stage of the synchronous tuning detector 43 _A ~ 43 _C, respectively, the logarithmic amplifiers 76 _A ~ logarithmically amplified after applying a predetermined amplification (amplification in accordance with the value of the corresponding Bessel functions) to a signal input 76 _C
Is provided. Furthermore, the provided adder 77 for adding the output of the logarithmic amplifier 76 _A to 76 _C, the output of the adder 77, A / D
Via the converter 45, to be supplied to the computer 47, constituting the signal demodulating circuit 36 _4.

[0066] The use of such a signal demodulating circuit 36 _4, an apparatus reflecting mirror 13 is vibrated sinusoidally, without performing signal processing such as FFT, the optical measuring device accurate results are obtained It can be formed. In FIG. 9, only three components are extracted from the output of the amplifier, but it goes without saying that more components may be extracted.

<Second Embodiment> FIG. 10 shows a second embodiment of the present invention.
1 shows a configuration of an optical measurement device according to an embodiment. The optical measuring device according to the second embodiment is a device in which each optical path of the optical measuring device according to the first embodiment is formed using an optical fiber (a polarization maintaining optical fiber). For this reason, in the optical measurement device of the second embodiment, instead of the optical multiplexer 17 and the optical multiplexer / demultiplexer 11 (of intensity division type) using a half mirror, a distribution-coupled optical multiplexer 17 'and an optical multiplexer / demultiplexer are used. A corrugator 11 'is used.
Each element constituting the optical measuring device of the second embodiment is the first component.
Since they have exactly the same functions as the corresponding elements of the embodiment, the description will be omitted.

As described above, when the optical measuring device is formed by using the optical fiber, the construction of the optical system is relatively easy, and the size can be reduced. Although the optical measuring device of the second embodiment is configured using the polarization maintaining optical fiber, it is obvious that a single mode optical fiber may be used. However, single-mode optical fibers are inferior in polarization stability to polarization-maintaining optical fibers.Therefore, when single-mode optical fibers are used, devices that are susceptible to disturbances and temperature changes are formed. Would. Therefore, it is desirable to use a polarization-maintaining optical fiber when configuring an optical measurement device using an optical fiber.

<Third Embodiment> FIG. 11 shows a third embodiment of the present invention.
1 shows a configuration of an optical measurement device according to an embodiment. As is clear from the figure, the optical measurement device of the third embodiment is a device in which the reference light modulation mechanism 71 ^* is mounted instead of the reference light modulation mechanism 71 in the optical measurement device of the first embodiment.

As shown, the reference light modulation mechanism 71
^* Is composed of the reflection mirror 13, the movement / movement mechanism 30 ^*, and the position sensor 50. The fluctuation / movement mechanism 30 ^* is composed of a piezo element and its driving circuit, like the minute fluctuation mechanism 30. However, the piezo element in the fluctuation / movement mechanism 30 ^*
As compared with the piezo element in the minute fluctuation mechanism 30, the position of the reflection mirror 13 can be changed largely (large element).

The drive circuit in the fluctuation / movement mechanism 30 ^* is provided with a control command and the like which the movement mechanism 31 and the minute fluctuation mechanism 30 in the optical measuring device of the first embodiment respectively receive from the computer 47. It is a circuit that accepts all. That is, the drive circuit receives drive profile designation data, a control command for instructing movement of the center position of the reflection mirror 13, a control command for instructing the start of the fluctuation movement of the reflection mirror 13, and the like. When a control command instructing movement of the center position of the reflection mirror 13 is input, the drive circuit controls the piezo element so that the reflection mirror 13 is moved to the position specified by the control command. When a control command instructing the start of the fluctuating movement of the reflecting mirror 13 is input, the reflecting mirror 13 performs the movement specified by the drive profile specifying data around the position of the reflecting mirror 13 at that time. The piezo element is controlled so that That is,
The drive circuit in the fluctuation / movement mechanism 30 ^* is a computer 4
In accordance with the instruction of FIG. 7, a control signal in which the vertical axis of FIG. 3C is read as a voltage is supplied to the piezo element.

Since there is no component equivalent to the member 35 in the reference light modulation mechanism 71 ^* , the position sensor 50 is fixed to the housing of the optical measuring device. Reference numeral 50 functions as a sensor that outputs a position signal indicating the actual position of the reflection mirror 13 instead of the displacement signal, and the synchronous tuning detector 43 performs synchronous tuning detection using the position signal.

As described above, in the optical measuring device of the third embodiment, the movement of the reflecting mirror 13 (change of the depth of the measuring point) and the modulation of the reference light are realized by one mechanism. For this reason, the optical measuring device according to the third embodiment is a device that can be configured at lower cost than the optical measuring device according to the first embodiment. In addition, the device can be easily miniaturized.

<Fourth Embodiment> An optical measuring device according to a fourth embodiment is a modification of the optical measuring device according to the second embodiment, and is different from the optical measuring device according to the second embodiment in reference light. A modulation mechanism is provided.

FIG. 12 shows the structure of a reference light modulation mechanism 71 "provided in the optical measuring apparatus according to the fourth embodiment. As shown in the figure, the reference light modulation mechanism 71" has the reference light from the optical fiber 21 '. Is provided with a lens system 81a for converting the light into parallel light. The lens system 81b and the optical fiber 86 are provided at the position where the parallel light from the lens system 81a is incident. The lens system 81b and the optical fiber 86 are fixed to a member 89 whose position is moved by a driving mechanism 85, and the lens system 81b is
The parallel light from the light source is collected and introduced into the optical fiber 86.

The optical fiber 86 is connected to the photocoupler 82. An optical fiber 87 in which a part is wound around a cylindrical piezo element 83 is mounted on the photocoupler 82.
Are connected to each other, and the light introduced into the optical fiber 86 passes through the photocoupler 82 and the optical fiber 87, then passes through the photocoupler 82 again, and passes through the lens system 81b,
The light reaches the optical multiplexer / demultiplexer 11 'via 81a.

The piezo element 83 is electrically connected to a piezo element drive circuit 84. Piezo element drive circuit 8
4 receives drive profile designation data from the computer 47 and a control command for instructing the start of minute fluctuation, similarly to the drive circuit in the minute fluctuation mechanism 30. When a control command instructing the start of the minute fluctuation is input, a control signal corresponding to the drive profile instruction data is supplied to the piezo element 83, similarly to the drive circuit in the minute fluctuation mechanism 30. To start processing. Then, the drive mechanism 85 performs exactly the same operation as the drive mechanism 31 in the second or first embodiment. In other words, the driving mechanism 85 moves the member 89 in accordance with an instruction from the computer, thereby moving the lens system 81a and the lens system 81.
The distance between b, that is, the optical path length of the reference light is changed. Since the light is collimated by the lens system 81a, no problem occurs in the measurement system and the optical system even if the distance between the lens systems 81a and 81b is changed.

In the optical measuring device of the fourth embodiment, as a result of the control by the piezoelectric element driving circuit 84, the optical fiber 87
Since the length of the portion wound around the piezo element 83 varies, the reference light is frequency-modulated.
Therefore, the optical measuring device according to the fourth embodiment functions similarly to the optical measuring device according to the second embodiment.

In this optical measuring device, the position sensor 5
Since a device equivalent to 0 cannot be provided, by adding a function of outputting a displacement signal (actually, a signal obtained by attenuating a control signal) to the piezo element driving circuit 84,
In the signal modulation circuit, synchronous detection can be performed.

<Fifth Embodiment> The optical measuring apparatus according to the fifth embodiment is designed so that the measurement can be performed without lowering the sensitivity even if the sample to be measured has birefringence.
It is a modification of the optical measurement device of the embodiment.

As shown in FIG. 13, the optical measuring apparatus according to the fifth embodiment has a polarizer 60 provided between the light source 10 and the optical multiplexer 17 'of the optical measuring apparatus according to the second embodiment. A polarizer 61 is also provided between the optical system for light 14 and the sample 1 to be measured.
Is provided.

Hereinafter, the operation of the optical measuring apparatus according to the fifth embodiment (the functions of the polarizers 60 and 61) will be described. In the optical measuring device according to the fifth embodiment, the light from the light source 10
Is polarized in a certain direction. The light from the polarizer 60 passes through an optical path 20 'composed of a polarization maintaining optical fiber, and is separated into reference light and measurement light by an optical multiplexer / demultiplexer 11'. The reference light is supplied to a reference light modulation mechanism 71 via an optical path 21 ′ composed of a polarization maintaining optical fiber, and is modulated. Also,
The measurement light passes through an optical path 22 ′ composed of a polarization-maintaining optical fiber, a measurement light optical system 14, and a polarizer 61, and then passes through the sample 1
Will be introduced. The polarizer 61 supplies the light from the measurement light optical system 14 to the measurement target sample 1 as it is, and changes the polarization state of the measurement light converted into, for example, elliptically polarized light by birefringence in the measurement target sample 1. , An optical circuit for returning to the original polarization state. For this reason, when the polarizer 61 is not provided as in the optical measuring device of the second embodiment, a level corresponding to the magnitude of the component having the same polarization direction as the reference light included in the elliptically polarized light is used. While the interference light including the intensity modulation component is incident on the detector 40, the elliptically polarized light is returned to the linearly polarized light by the polarizer 61 in the optical measurement apparatus according to the present embodiment. Is incident on the detector 40. Therefore, according to the present optical measurement device, the measurement of the sample 1 to be measured can always be performed with high accuracy without being affected by birefringence.

In this optical measuring apparatus, a polarizer is provided only on the measurement light side. However, a polarizer is provided on the reference mirror side or on the reference mirror side so that the reference light reflected by the reference mirror can be used. , And the light from the sample 1 to be measured, as a result,
You may make it interfere.

As described above in detail, in the optical measuring device of each embodiment, the optical characteristic data of each measuring point is measured without moving the position to be measured. For this reason, as schematically shown in FIG. 14, the position resolution at each measurement point is only limited by the coherent length of the light used for measurement. The position resolution is not limited by the speed. In addition, since the optical characteristic data of each measurement point is measured without moving the position to be measured, the device can measure a plurality of measurement points at the same depth at high speed. I have. Furthermore, since the measurement time at each measurement point can be set arbitrarily, the use of the present optical measurement device enables data of desired accuracy to be collected in a shorter time as compared with a conventional optical measurement device.

<Modifications> Various modifications of the optical measuring device of each embodiment are possible. For example, the reference light modulation mechanism 71 ″ shown in the figure can be applied to the optical measuring device of the first embodiment. In the optical measuring device of each embodiment, the SLD is used as the light source 10. Any light source that can generate short coherent long light can be used as the light source 10. For example,
As the light source 10, a pulsed laser, a continuous wave laser generating light with poor coherence, a light emitting diode, a laser operated with a current not exceeding a threshold, a multimode laser, and a fluorescent light source excited by laser may be used. it can. Further, a combination of a coherent light source and a unit that randomly modulates coherent light generated by the coherent light source and generates irregular jumps in phase can be used as the light source 10.

In each embodiment, the minute fluctuation mechanism is
Although it is configured using a piezo element, it is obvious that the minute fluctuation mechanism may be configured using a crystal resonator, an electromagnetic resonator, a microphone, a tuning fork, or the like. Similarly, the moving mechanism may be configured using a device other than the stepping motor, for example, a DC motor or an electromagnetic actuator.

In each of the embodiments, a signal for changing the focal position is supplied from the reference light modulation mechanism to the measuring light optical system. Then, a command for designating x, y, and z is output, and a signal for changing the optical path length of the reference light is supplied to the reference light modulation mechanism by the measuring light optical system that has received such a command. As a matter of course, the optical measuring device may be configured as described above.

The optical measuring device may be configured so that the direction in which the measuring light is irradiated is fixed and the relative position of the sample to be measured with respect to the measuring light can be changed. That is,
The apparatus may be configured such that the measurement point is moved by changing the position of the sample to be measured.

Further, the optical measuring device may be configured so that not only frequency modulation but also amplitude modulation is performed on the reference light, and the optical measuring device may be configured such that only amplitude modulation is performed. Is also good. Further, by providing a polarization plane rotator by a magnetic field such as a Faraday element in the reference optical path, the apparatus may be configured such that the modulation in the form of rotation (modulation) of the polarization plane is performed on the reference light.

The apparatus may be configured so that not only the modulation of the reference light but also the modulation of the measurement light is performed. For example, an amplitude modulation element or the like is further provided on the measurement optical path side so that amplitude modulation is performed on the measurement light, and modulation according to frequency modulation on the reference light and amplitude modulation on the measurement light is performed on the interference light. The device can also be configured such that:

[0091]

According to the optical measuring apparatus of the present invention, the optical characteristic data at the measuring point at an arbitrary position can be measured without moving the position to be measured. For this reason, according to the optical measuring device of the present invention, only data relating to a necessary measuring point can be measured at a high position resolution and at a high speed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical measurement device according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation procedure of a computer included in the optical measurement device according to the first embodiment.

FIG. 3 is a time chart for explaining the operation of the optical measuring device according to the first embodiment.

FIG. 4 is a block diagram of a circuit that can be used to extract an intensity modulation component from the interference light in the optical measurement device according to the first embodiment.

FIG. 5 is an explanatory diagram of a Bessel function.

FIG. 6 is a diagram showing a power spectrum obtained when a reference mirror is driven in a sine wave shape with an amplitude such that a zero-order Bessel function becomes zero.

FIG. 7 is a diagram showing a power spectrum obtained when a reference mirror is driven in a triangular waveform.

FIG. 8 is a block diagram of a signal demodulation circuit that can be applied to the optical measurement device of the first embodiment.

FIG. 9 is a block diagram of a signal demodulation circuit that can be applied to the optical measurement device of the first embodiment.

FIG. 10 is a configuration diagram of an optical measurement device according to a second embodiment of the present invention.

FIG. 11 is a configuration diagram of an optical measurement device according to a third embodiment of the present invention.

FIG. 12 is a main part configuration diagram of an optical measurement device according to a fourth embodiment of the present invention.

FIG. 13 is a configuration diagram of an optical measurement device according to a fifth embodiment of the present invention.

FIG. 14 is a diagram for describing a position resolution obtained by the optical measurement device according to each embodiment of the present invention.

FIG. 15 is a diagram for explaining one of the problems of the conventional optical measurement device.

[Explanation of symbols]

 10, 15 light source 11 optical multiplexer / demultiplexer 12, 33 lens system 13 reflecting mirror 14 optical system for measuring light 16 total reflection mirror 17 optical multiplexer 30 minute fluctuation mechanism 31 moving mechanism 32 focal position control mechanism 40 detector 41 amplifier 42 band Pass filter 43 Synchronous tuning detector 44 Integrator 45 A / D converter 46 Signal demodulation circuit 47 Computer 48 Monitor 49 Printer 50 Position sensor 60, 61 Polarizer 71 Reference light modulation mechanism

Claims (16)

[Claims] An optical multiplexing means for multiplexing incident light; a light generating means for generating light having a short coherent length; and a light generated by the light generating means is converted into a reference light and a measuring light. Light separating means to be separated, the distance between the optical path length of the reference light separated by the light separating means and the reference light reference optical path length reaching the optical multiplexing means is not more than a value corresponding to the positional resolution required for measurement. And a reference light introducing unit that modulates the reference light and introduces the light into the optical multiplexing unit, and introduces the measurement light separated by the light separating unit into the measurement target sample, and reflects the measurement light by the measurement target sample. Measuring light introducing means for introducing the scattered measuring light into the optical multiplexing means; photoelectric conversion means for outputting an electric signal at a level corresponding to the intensity of the light multiplexed by the optical multiplexing means; Electricity output by means An optical measurement apparatus comprising: an acquisition unit configured to acquire optical characteristic data on one measurement point of the measurement target sample using a signal and a modulation frequency of the reference light by the reference light introduction unit. 2. The optical measuring apparatus according to claim 1, wherein a time-varying pattern of the modulation applied to the reference light by the reference light introducing means is a sinusoidal pattern. 3. The sine wave pattern is a pattern whose amplitude is set such that a DC component included in an electric signal output by the photoelectric conversion unit becomes “0”. 3. The optical measuring device according to 2. 4. The reference light introducing means comprises: a reflector for reflecting the reference light separated by the light separating means; and a reflected reference light introducing means for introducing the reference light reflected by the reflector to the optical multiplexing means. And a reflector moving mechanism for moving the position of the reflector; and a reflector moving mechanism control means for modulating the reference light by controlling the reflector moving mechanism. An optical measuring device according to any one of claims 1 to 3. 5. The reference light introducing means includes: an optical fiber through which the reference light separated by the light separating means passes; a deforming mechanism for deforming the optical fiber; and controlling the deforming mechanism. 4. An optical measuring apparatus according to claim 1, further comprising a deformation mechanism control means for modulating the reference light passing through the optical fiber. 6. A detecting means for detecting a modulation frequency of a modulation given to the reference light by the reference light introducing means,
5. The optical measurement device according to claim 1, wherein the acquisition unit uses an electric signal output by the photoelectric conversion unit and a modulation frequency detected by the detection unit. apparatus. 7. A position changing unit that changes a position of a measurement point at which optical characteristic data is obtained by the obtaining unit in an optical axis direction of the measurement light by changing the reference light reference optical path length. The optical measurement device according to any one of claims 1 to 6, further comprising: 8. The measuring light introducing means may be arranged so that the measuring light separated by the light separating means has a focal position corresponding to a change amount of the reference light reference optical path length by the optical path length changing means. 8. The optical measuring apparatus according to claim 7, wherein said optical measuring apparatus is introduced into said sample to be measured. 9. An optical axis direction of the measurement light of a measurement point at which optical data is acquired by the acquisition means by changing an optical path length of the measurement light from the light separation means to the optical multiplexing means. Position changing means for changing the position of
The optical measurement device according to claim 1, further comprising: 10. The measuring light introducing means causes the measuring light separated by the light separating means to have a focal position corresponding to a change amount of the optical path length of the measuring light by the optical path length changing means. 10. The optical measuring apparatus according to claim 9, wherein the optical measuring apparatus is introduced into the sample to be measured. 11. The apparatus according to claim 1, further comprising a measuring light introducing position changing unit for changing an introducing position of the measuring light by the measuring light introducing unit into the measurement target sample. Item 11. The optical measuring device according to any one of Items 10. 12. A storage unit for storing introduction position information on one or more measurement points in a form in which the order of use is known, and said obtaining unit, based on the introduction position information stored in said storage unit, said measuring light introduction. 12. The optical measuring apparatus according to claim 11, wherein by controlling the position changing unit, optical characteristic data regarding each measurement point whose introduction position information is stored in the storage unit is obtained. 13. A measuring light introducing position changing means for changing an introducing position of the measuring light by the measuring light introducing means to the sample to be measured, and introducing position information and light relating to one or more measuring points. A storage unit that stores the position information composed of the axial position information in a form in which the use order is understood, and the acquisition unit is based on the introduction position information and the optical axis direction position information that constitute the position information stored in the storage unit.
The optical characteristic data relating to each measurement point whose position information is stored in the storage unit by controlling the measurement light introduction position changing unit and the position control unit, respectively. Item 11. The optical measuring device according to any one of Items 10. 14. The storage unit stores, in a form in which the use order can be understood, position information and measurement time information including one or more introduction points information and optical axis direction position information regarding one or more measurement points. For each measurement point at which the position information is stored in the storage means, during a time corresponding to the measurement time information associated with the measurement point, using an electric signal output by the photoelectric conversion means. 14. The optical measuring device according to claim 13, wherein optical characteristic data is acquired. 15. Polarization for adjusting the polarization state of one or both of the measurement light and the reference light such that the measurement light from the sample to be measured introduced into the optical multiplexing means and the reference light interfere with each other. The optical measuring device according to claim 1, further comprising a state adjusting unit. 16. Light combining means for combining incident light, light generating means for generating light having a short coherent length, and light generated by the light generating means as reference light and measurement light. A light separating means for separating, a reference light introducing means for introducing the reference light separated by the light separating means to the optical multiplexing means, and a measuring light separated by the light separating means for introducing into the sample to be measured and measuring A means for introducing the measurement light reflected and scattered by the target sample into the optical multiplexing means, wherein a distance between an optical path length from the light separation means of the measurement light to the optical multiplexing means and a measurement light reference optical path length is different. , While maintaining a state that is equal to or less than the value corresponding to the positional resolution required for measurement,
A measuring light introducing unit that modulates the measuring light and introduces the light into the optical multiplexing unit; a photoelectric conversion unit that outputs an electric signal according to the intensity of the light multiplexed by the optical multiplexing unit; Using an electric signal to be output and a modulation frequency of the modulation applied to the measurement light by the measurement light introduction unit, an acquisition unit that acquires optical characteristic data regarding one measurement point of the measurement target sample. Optical measuring device.