JPH068935B2 - Light-to-light conversion element - Google Patents

Description

The present invention relates to a light-to-light conversion element suitable for an imaging device, an optical writing projection device, and the like.

(Prior Art) As a light-to-light conversion element configured to input an optical image and output the optical image also as an output, for example, a liquid crystal type optical modulator, a photoconductive Pockels effect element, a microchannel type Spatial modulation elements such as optical modulators, or those of various configuration forms such as elements configured using photochromic material, for example, optical writing projection device, an element for optical parallel processing of an optical computer, It has been attracting attention as an element for recording an image, and the applicant company has also proposed a high-resolution image pickup device using a light-to-light conversion element.

FIG. 8 is a side sectional view showing a configuration example of a conventional light-to-light conversion element. In the light-to-light conversion element shown in FIG. 8, 1 and 2 are glass plates, 3 and 4 are transparent electrodes, and 5 are transparent electrodes. , 6, 1
1 is a terminal, 7 is a photoconductive layer, 12 is a light shielding layer, 8 is a dielectric mirror, 9 is an optical member (for example, a nematic liquid crystal layer) that changes the state of light according to the intensity distribution of the applied electric field, W
L is writing light, RL is reading light, and EL is erasing light.

In the light-to-light conversion element shown in FIG.
A circuit composed of a power source 10 and a changeover switch SW is connected between 6 and the movable contact of the changeover switch SW is switched to the fixed contact WR side by the changeover control signal supplied to the input terminal 11 of the changeover control signal in the changeover switch SW. And put
By applying the voltage of the power source 10 between the transparent electrodes 3 and 4 described above,
An electric field is applied between both ends of an optical member (for example, a nematic liquid crystal layer) 9 that changes the state of light according to the intensity distribution of the applied electric field, and writing from the glass plate 1 side of the light-to-light conversion element is performed. When the incident light WL is incident and the incident writing light WL is transmitted through the glass plate 1 and the transparent electrode 3 to reach the photoconductive layer 7, the electric resistance value of the photoconductive layer 7 is the incident light that has reached it. Therefore, a charge image corresponding to the optical image due to the incident light reaching the photoconductive layer 7 is generated at the boundary surface between the photoconductive layer 7 and the light shielding layer 12.

As described above, the movable contact of the changeover switch SW is the fixed contact W.
In the state of being switched to the R side, between the transparent electrodes 1 and 2 to which the voltage of the power source 10 is applied via the terminals 5 and 6, the light shielding layer 12 and the dielectric mirror are provided with respect to the photoconductive layer 7 described above. 8 and the like, an electric field having an intensity distribution corresponding to the optical image by the incident light is applied to the nematic liquid crystal layer 9 provided in a serial relationship, and the liquid crystal in the nematic liquid crystal layer 9 has an optical axis of its molecule. When the readout light RL is projected to the glass plate 2 side without being parallel to the polar plate, the reflected light in a state including image information according to the electric field intensity applied to the liquid crystal layer 9 due to the electro-optical effect of the nematic liquid crystal. Then, an optical image corresponding to the optical image of the subject appears on the glass plate 2 side.

That is, the readout light RL projected on the glass plate 2 side proceeds in the order of the transparent electrode 4 → nematic liquid crystal layer 9 → dielectric mirror 8 → light-shielding layer 12, and most of the light is transmitted by the dielectric mirror 8 to the glass plate. Although it returns to the 2 side as reflected light, the reflected light is in a state of containing image information according to the electric field intensity applied to the liquid crystal layer 9 due to the electro-optical effect of the nematic liquid crystal, so that the glass plate 2 An optical image corresponding to the optical image of the subject appears on the side.

Then, it is projected on the glass plate 2 side as described above, and the transparent electrode 4 → nematic liquid crystal layer 9 → dielectric mirror 8 → light-shielding layer 1
The light not reflected by the dielectric mirror 8 in the read light RL that travels as shown in 2 is shielded by the light shielding layer 12 so as not to travel to the photoconductive layer 7 side. Even if the light is projected onto the glass plate 2 side, the electric resistance value of the photoconductive layer 7 does not change. Therefore, even when the read light RL is projected onto the boundary surface between the photoconductive layer 7 and the light shielding layer 12. The charge image generated corresponding to the optical image by the incident light is not changed.

(Problems to be Solved by the Invention) By the way, in order to erase the information written in the optical-optical switching element by the writing light WL as described above, the input terminal 11 of the changeover control signal in the changeover switch SW described above is used. To the fixed contact E side to switch the movable contact of the changeover switch SW to the terminal 5 in the optical-to-optical conversion element.
After making the electric potential of 6 the same so that no electric field is generated between the transparent electrodes 3 and 4, the erasing light EL having a uniform intensity distribution from the side of the glass plate 1 which is the incident side of the writing light WL.
Is applied to the photoconductive layer 7 through the glass plate 1 and the transparent electrode 3 to reduce the electric resistance value of the photoconductive layer 7 to the photoconductive layer 7. The charge image generated on the boundary surface with the light shielding layer 12 is erased.

As described above, in the conventional light-to-light conversion element, the erasing light incident side used when erasing the previously written optical information is the same as the writing light WL incident side is that the reading light RL. The light-shielding layer 12 is provided between the light-incident side and the photoconductive layer 7.
Therefore, when the erasing light is made incident from the side on which the reading light RL is made incident, the erasing light is generated by the light shielding layer 1 described above.
It is blocked by 2 and cannot reach the photoconductive layer 7. Therefore, when the erasing light is incident from the side on which the reading light RL is incident, the photoconducting layer 7 and the light shielding layer 12 are exposed to the boundary surface. This is because the generated charge image cannot be erased.

The above-mentioned point is, for example, an imaging device having a configuration in which an imaging optical system is required to be provided on the side where the writing light WL is incident, and other cases where the erasing light is incident on the side where the writing light WL is incident. This is a major problem when the light-to-light conversion element is used in a device having a configuration in which it is difficult to provide the device.

In a light-to-light conversion element including an optical member that changes the state of light according to the intensity distribution of the applied electric field, the state of light is changed according to the intensity distribution of the applied electric field. An anisotropic crystal such as a lithium niobate single crystal may be used as the optical member.

That is, an anisotropic crystal such as a lithium niobate single crystal has a phase difference between an ordinary ray and an extraordinary ray passing therethrough,
Since it has the property of changing according to the electric field strength applied to the anisotropic crystal, it can be used as a constituent member of a light-to-light conversion element.

However, the phase difference between the ordinary ray and the extraordinary ray passing through the anisotropic crystal is not only changed according to the electric field strength applied to the anisotropic crystal as described above, but also is anisotropic as is well known. The anisotropic crystal used in the light-to-light conversion element as an optical member that changes the state of light according to the intensity distribution of the applied electric field as described above, since it also changes depending on the thickness of the crystalline substance. , If the thickness of the light-optical conversion element is not made to be constant with high accuracy, shading will occur in the reproduced image read from the optical-optical conversion element. Since it is difficult to create an anisotropic crystal of uniform thickness that does not cause shading in the image due to the above causes,
A solution for it was also sought.

(Means for Solving the Problems) The present invention provides a transparent electrode, a photoconductive layer, and wavelength selectivity that allows light in the wavelength range of read light to be reflected while transmitting light in the wavelength range of erase light. A light-to-light conversion element, which is formed by laminating an optical member having the following: an optical member that changes the state of light according to the intensity distribution of an applied electric field; and a transparent electrode.
Between the two transparent electrodes, at least a photoconductive layer member and a dielectric mirror having wavelength selectivity capable of reflecting light in the wavelength range of read light and transmitting light in the wavelength range of erase light are applied. The light from the object is incident on the photoconductive layer member side of the light-to-light conversion element in which the light modulation material layer member that changes the light state according to the intensity distribution of the electric field is laminated to the light-to-light conversion element. The means for generating a charge image corresponding to the optical image and the read light incident on the light-to-light conversion element from the light-modulation material layer member side of the light-to-light conversion element are used to generate a charge image corresponding to the optical image of the subject. An image pickup device including a unit for reading out as an optical image and a unit for erasing a charge image corresponding to the optical image of the subject, as well as at least a photoconductive layer member between two transparent electrodes, and a wavelength range of read light. Reflected light In addition, a dielectric mirror having wavelength selectivity that allows transmission of light in the wavelength range of erasing light and a light modulation material layer member that changes the light state according to the intensity distribution of the applied electric field are laminated. Means for making light from a subject incident on the photoconductive layer member side of the light-to-light conversion element, and generating a charge image corresponding to the optical image of the subject in the light-to-light conversion element, and a light modulator for the light-to-light conversion element. Means for reading, as an optical image, a charge image corresponding to the optical image of the subject by reading light incident on the light-to-light conversion element from the layer member side, and means for erasing the charge image corresponding to the optical image of the subject. And a light modulation material layer in which the state of light changes in accordance with the intensity distribution of the applied electric field in the incident light path of the read light with respect to the light-to-light conversion element to which the optical image of the subject is provided. Element In addition to providing an optical member for shading correction that is configured to include, it is possible to correct shading of light generated in a reproduced optical image in correspondence with the undesired birefringence state of the light modulation material layer member in the light-to-light conversion element described above. The present invention provides an image pickup apparatus comprising: a correction signal generator that applies a shading correction electric field to the shading correction optical member.

(Examples) Hereinafter, specific contents of the light-to-light conversion element of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a side view of an embodiment of a light-to-light conversion element of the present invention, and FIG. 2 is a wavelength selection that allows light in the wavelength range of read light to be reflected while transmitting light in the wavelength range of erase light. Of characteristic curves showing an example of wavelength selection characteristics of an optical member having optical properties, FIG. 3 is a block diagram for explaining the operation of the light-to-light conversion element of one embodiment of the present invention shown in FIG. 1, FIG. 4 and FIG. FIG. 5 is a perspective view showing a schematic configuration of different image pickup devices configured by using the light-to-light conversion element of one embodiment of the present invention, and FIG. 6 explains the operation principle of the image pickup device shown in FIG. FIG. 7 is a diagram for explaining anisotropic crystals having a non-uniform thickness.

In FIG. 1, 1 and 2 are glass plates, 3 and 4 are transparent electrodes,
Reference numerals 5 and 6 are terminals, 7 is a photoconductive layer, and 8R is an optical member having a wavelength selectivity capable of reflecting light in the wavelength range of the reading light and transmitting light in the wavelength range of the erasing light. As the optical member 8R, it is possible to use, for example, a dichroic filter composed of a multilayer film of a thin film of SiO2 and a thin film of TiO2.

Reference numeral 9 denotes an optical member that changes the state of light according to the intensity distribution of the applied electric field (for example, an electro-optical effect crystal such as a lithium niobate single crystal, or an optical member composed of a nematic liquid crystal layer). In the figure, WL represents writing light, RL represents reading light, and EL represents erasing light.

FIG. 2 is a curve diagram exemplifying the wavelength selectivity of the optical member 8R having wavelength selectivity capable of reflecting the light in the wavelength range of the reading light and transmitting the light in the wavelength range of the erasing light. 2 shows that the optical member 8R having the characteristics shown in FIG. 2 (a) is configured as an optical low-pass filter, and FIG. The optical member 8R having the characteristics shown in b) represents that it is configured as an optical high pass filter, and further, the optical member having the characteristics shown in (c) of FIG. The member 8R is shown to be constructed as an optical bandpass filter, and the optical member 8R having the characteristics shown in FIG. 2 (d) is constructed as an optical bandstop filter. It means that

That is, in the light-to-light conversion element of the present invention shown in FIG. 1, the optical member 8R used as a part of the component thereof, that is, the light in the wavelength range of the read light is reflected and erased. The optical member 8R having a wavelength selectivity capable of transmitting light in the wavelength range of light is shown in FIG.
It is possible to use the optical member 8R having wavelength selectivity whose wavelength selection characteristics are exemplified in (d) to (d).

In the light-to-light conversion element of the present invention provided with the optical member 8R having the wavelength selection characteristic as illustrated in FIGS. 2A to 2D, the optical member 8R is used as the reading light to be incident thereon. In the wavelength region having a low light transmittance, and as the erasing light to be incident thereon, light in a wavelength region having a high light transmittance in the optical member 8R is used. In the light conversion element, the erasing light can be made to enter from the incident side of the reading light.

When optical information is written in the light-to-light conversion element having the structure shown in FIG. 1, the power source 10 is switched to the terminals 5 and 6 of the light-to-light conversion element as shown in FIG. Connect the circuit consisting of switch SW and changeover switch SW
In accordance with the switching control signal supplied to the input terminal 11 of the switching control signal in, the movable contact of the changeover switch SW is switched to the fixed contact WR side, and the transparent electrodes 3 and 4 described above are set.
A voltage of a power supply 10 is applied between them so that an electric field is applied between both ends of the photoconductive layer 7, and the writing light WL is made incident from the glass plate 1 side of the light-to-light conversion element. The optical information is written to.

That is, when the writing light WL that has entered the light-to-light conversion element as described above passes through the glass plate 1 and the transparent electrode 3 and reaches the photoconductive layer 7, the incident light whose electric resistance value of the photoconductive layer 7 has reached it. In order to change corresponding to the optical image by light,
A boundary surface between the photoconductive layer 7 and the optical member 8R (optical member 8R having a wavelength selectivity capable of reflecting light in the wavelength range of the reading light and transmitting light in the wavelength range of the erasing light) has a light A charge image corresponding to the optical image due to the incident light reaching the conductive layer 7 is generated.

In order to reproduce the optical information written in the form of the charge image corresponding to the optical image by the incident light as described above from the light-to-light conversion element, the movable contact of the changeover switch SW is set to the fixed contact WR side. In the switched state, the voltage of the power source 10 is applied between the transparent electrodes 1 and 2 via the terminals 5 and 6, and a constant light intensity from a light source (not shown) is applied from the glass plate 2 side. Can be performed by projecting the reading light RL.

That is, as described above, the photoconductive layer 7 and the optical member 8R in the light-to-light conversion element in which the optical information is written by the incident light (the light in the wavelength range of the read light is reflected and the wavelength range of the erase light is changed). Since a charge image corresponding to the optical image due to the incident light reaching the photoconductive layer 7 is formed at the interface with the optical member 8R) having wavelength selectivity capable of transmitting light, the photoconductive layer described above is formed. The optical member 9 (for example, the lithium niobate single crystal 9) provided in a serial relationship with the optical member 8R with respect to 7 is in a state in which an electric field having an intensity distribution corresponding to the optical image by the incident light is applied. Has been done.

Since the refractive index of the lithium niobate single crystal 9 changes according to the electric field due to the electro-optical effect, the photoconductive layer 7 described above is in a state in which the electric field having the intensity distribution corresponding to the optical image by the incident light is applied. On the other hand, the refractive index of the lithium niobate single crystal 9 provided in series with the optical member 8R is the same as that of the photoconductive layer 7 and the optical member in the light-to-light conversion element due to the writing of optical information by the incident light described above. 8
Incident light reaching the photoconductive layer 7 at the interface with R (optical member 8R having a wavelength selectivity capable of reflecting light in the wavelength range of read light and transmitting light in the wavelength range of erase light) The image changes according to the electric charge image generated corresponding to the optical image.

Therefore, when the reading light RL is projected on the glass plate 2 side, the reading light RL projected on the glass plate 2 side as described above is transparent electrode 4 → lithium niobate single crystal 9 → optical member 8R ( While reflecting the light in the wavelength range of the read light,
The optical member 8R has a wavelength selectivity that allows light in the wavelength range of the erasing light to pass therethrough.

The read light RL is reflected by the optical member 8R having a wavelength selectivity that allows the light in the wavelength range of the read light to be reflected and the light in the wavelength range of the erase light to be transmitted, and is reflected to the glass plate 2 side. However, since the refractive index of the lithium niobate single crystal 9 changes according to the electric field due to the electro-optic effect, the reflected light of the read light RL is the lithium niobate single crystal 9 due to the electro-optic effect of the lithium niobate single crystal 9. Image information corresponding to the intensity distribution of the electric field applied to the crystal 9 is included, and a reproduced optical image corresponding to the optical image by the incident light is generated on the glass plate 2 side.

The reading light RL projected from the glass plate 2 side in the above-described reproducing operation is, as described above, the transparent electrode 4 → the lithium niobate single crystal 9 → the optical member 8R (while reflecting the light in the wavelength range of the reading light. , The optical member 8R having a wavelength selectivity capable of transmitting light in the wavelength range of the erasing light) → progresses toward the photoconductive layer 7 as described above.
L is an optical member having a wavelength selectivity such that it can reflect the light in the wavelength range of the reading light and transmit the light in the wavelength range of the erasing light before it reaches the photoconductive layer 7. By being reflected by the member 8R), the optical path such as the lithium niobate single crystal 9 → the transparent electrode 4 → the glass plate 2 is traced.
There is no adverse effect on the charge image due to the incident light that has been written to and reached.

Thus, in the light-to-light conversion element of the present invention, the glass plate 1
The writing operation is performed by making the writing light WL incident from the side, and the optical image is reproduced by making the reading light RL incident on the glass plate 2 side.

Next, a method of erasing information written in the light-to-light conversion element of the present invention shown in the first figure will be described. When erasing the information written in the light-to-light conversion element of the present invention shown in FIG. 1, the changeover switch SW connected between the terminals 5 and 6 of the light-to-light conversion element shown in FIG. In accordance with the switching control signal supplied to the input terminal 11 of the switching control signal in, the movable contact of the changeover switch SW is switched to the fixed contact E side, and the transparent electrodes 3 and 4 are electrically short-circuited to be transparent. The electrodes 3 and 4 are set to the same potential so that an electric field is not applied between both ends of the photoconductive layer 7, and then the erasing light EL is incident from the glass plate 2 side of the light-to-light conversion element.

As described above, the erasing light EL that is incident on the glass plate 2 side of the light-to-light conversion element is glass plate 2 → transparent electrode 4 → lithium niobate single crystal 9 → optical member 8R (reflects light in the wavelength range of read light). At the same time, an optical member 8R having a wavelength selectivity capable of transmitting light in the wavelength range of the erasing light) → photoconductive layer 7
Reach the photoconductive layer 7 by a path like
Reduces the electric resistance of the photoconductive layer 7 by
Image formed on the boundary surface between the optical member 8R and the optical member 8R (optical member 8R having wavelength selectivity capable of reflecting light in the wavelength region of read light and transmitting light in the wavelength region of erase light) To erase.

As described above, in the light-to-light conversion element of the present invention, the photoconductive layer 7 and the optical member 8R (a wavelength that allows light in the wavelength range of read light to be reflected and allows light in the wavelength range of erase light to be transmitted during the writing operation are performed. The charge image formed on the boundary surface with the optical member 8R) having selectivity is erased by the erasing light EL that is incident on the light-to-light conversion element from the incident side of the reading light RL in the light-to-light conversion element. Therefore, an imaging device having a configuration in which it is necessary to provide an imaging optical system on the side on which the writing light WL enters, and an erasing light incidence device on the side on which the writing light WL enters are provided. However, the present invention can be easily applied to a device having a configuration mode having a difficult situation, and the present invention can satisfactorily solve the above-mentioned conventional problems.

FIG. 4 is a perspective view of an example of an image pickup apparatus configured by using the light-to-light conversion element of the present invention having the configuration described with reference to FIGS. 1 to 3, and FIG. PPC indicates the light-to-light conversion element of the present invention.
In the light-to-light conversion element PPC shown in the figure, the writing light WL indicated by the reference numeral WL in FIG. 1 and FIG.
Is attached to the surface side of the glass plate 1 on which is incident,
Further, the reference numeral 2 is attached to the front surface side of the glass plate 2 on which the reading light RL indicated by the reference numeral RL and the erasing light EL indicated by the reference numeral EL in FIGS. Then, only the correspondence with the light-to-light conversion element shown in FIGS. 1 and 3 is clarified, and for simplification of the illustration, a concrete description of other components in the light-to-light conversion element is made. The illustration is omitted.

In FIG. 4, O is a subject, L is an imaging lens, and BS1 and BS
Reference numeral 2 is a beam splitter, and PSr is a light source for reading light (as a light source PSr for reading light, for example, a flying spot scanner using a laser light can be used. Light source P
As Sr, it is assumed that a flying spot scanner that deflects the laser light in a predetermined manner is used), P
Se is a light source for erasing light, PLP is a polarizing plate, PD is a photodetector, and the light-to-light conversion element PPC illustrated in FIG.
In an image pickup apparatus configured using
Of the optical image of PPC by the imaging lens L
The writing light is incident on the glass plate 1 side.

The transparent electrodes 3 and 4 in the light-to-light conversion element PPC when in the writing mode and the reading mode have a third
As shown in the figure, since the voltage of the power supply 10 is applied through the changeover switch SW in the state where the movable contact is switched to the fixed contact WR side, the light corresponding to the optical image of the object O is captured as the writing light. In the light-to-light conversion element PPC provided to the glass plate 1 side through the lens L, as described above with reference to FIG. 3, the photoconductive layer 7 and the optical member 8R thereof are provided.
Incident reaching the photoconductive layer 7 at the interface with (optical member 8R having a wavelength selectivity capable of reflecting light in the wavelength range of the reading light RL and transmitting light in the wavelength range of the erasing light EL). A charge image corresponding to the optical image formed by the light (in FIG. 4, the inverted optical image of the subject O is shown upside down on the boundary surface between the photoconductive layer 7 and the optical member 8R in the light-to-light conversion element PPC. (Shown as a charge image in the shape of a letter)).

As described above, the optical information is written by the writing light from the glass plate 1 side, and the photoconductive layer 7 of the light-to-light conversion element PPC is formed.
And the optical member 8R (optical member 8R having wavelength selectivity capable of reflecting light in the wavelength range of the reading light RL and transmitting light in the wavelength range of the erasing light EL) are affected by incident light. In the state where the voltage of the power source 10 is applied through the changeover switch SW between the transparent electrodes 3 and 4 in the light-to-light conversion element PPC in the state where the charge image corresponding to the optical image is generated, the flying point scanning of the laser light is performed. The read light RL of the coherent light emitted from the light source PSr of the read light, which is configured as a device, is transmitted through the beam splitter BS1 and then reflected by the beam splitter BS2 to convert the light-to-light conversion element PP.
When projected from the side of the glass plate 2 in C, the read light RL projected on the side of the glass plate 2 is, as described above with reference to FIG. 3, the transparent electrode 4 → the lithium niobate single crystal 9 →
The optical member 8R (optical member 8R having wavelength selectivity that allows light in the wavelength range of the reading light RL to be reflected and transmits light in the wavelength range of the erasing light EL) to proceed.

The read light RL is reflected by the optical member 8R having a wavelength selectivity that allows the light in the wavelength range of the read light to be reflected and allows the light in the wavelength range of the erase light to be transmitted, and is reflected by the glass plate 2
Although it returns to the side as reflected light, the refractive index for the ordinary ray and the extraordinary ray of the lithium niobate single crystal 9 that the read light RL reciprocates as described above is as follows.
Since the electro-optical effect of the lithium niobate single crystal 9 changes differently according to the electric field strength applied to the lithium niobate single crystal 9, the reflected light of the read light RL is changed by the electro-optical effect of the lithium niobate single crystal 9. Crystal 9
Since the image information includes image information corresponding to the intensity distribution of the electric field applied to, the reproduced optical image corresponding to the optical image by the incident light is generated on the glass plate 2 side.

The light-to-light conversion element P is used when a flying spot scanner using laser light is used as the light source PSr of the read light RL.
Since the reproduced optical image appearing on the glass plate 2 side of the PC is formed by the flying spot scanning, the light of the reproduced optical image is the beam splitter BS2 and the polarizing plate PLP.
By being transmitted through and given to the photodetector PD, a video signal corresponding to the optical image of the object O is output from the photodetector PD.

In addition, as the above-mentioned photodetector PD to be used,
Depending on how the laser light is deflected by the light source PSr of the reading light RL, and how the photodetector PD is displaced in the sub-scanning direction, the appropriate configuration may be adopted. Of course it should be used.

In the image pickup apparatus shown in FIG. 4, it is necessary to write and read images of different subjects for each predetermined time length on the time axis to generate a video signal. In order to write and read images of different subjects for each predetermined time length, a new optical image of the subject is set for each predetermined time length on the time axis. Before being written, it is necessary to erase the charge image corresponding to the previously written optical image.

Then, the erasing operation in the image pickup device is performed during a predetermined time period before writing new optical images one after another on the time axis, which is an image output from the photodetector PD. Corresponding to the vertical blanking period in the video signal output from the photodetector PD, as in the case of the vertical blanking period in the signal, as described above with reference to FIG. The movable contact of the changeover switch SW is changed to the fixed contact E side by the changeover control signal supplied to the input terminal 11 of the changeover control signal in the changeover switch SW connected between the terminals 5 and 6, and the above-mentioned transparent The electrodes 3 and 4 are electrically short-circuited so that the transparent electrodes 3 and 4 have the same potential so that an electric field is not applied between both ends of the photoconductive layer 7. The Sahikari EL to radiation, the erasing light E
L is made to enter from the glass plate 2 side in the light-to-light conversion element PPC via the beam splitters BS1 and BS2.

As described above with reference to FIG. 3, the erasing light EL incident on the glass plate 2 side of the light-to-light conversion element is the glass plate 2 → transparent electrode 4 → lithium niobate single crystal 9 → optical member 8R (readout). An optical member 8R having a wavelength selectivity capable of reflecting light in the wavelength range of light and transmitting light in the wavelength range of erasing light → reaches the photoconductive layer 7 by a route such as the photoconductive layer 7. Then, the erasing light EL reduces the electric resistance value of the photoconductive layer 7, and the charge image formed on the boundary surface between the photoconductive layer 7 and the optical member 8R is erased.

By the way, a video signal is generated which is characterized by easy editing, trimming, and other image signal processing, and easy recording and reproduction by using a reversible recording member capable of erasing a recorded signal. As an image pickup device for performing the above, an image pickup device configured by using a light-to-light conversion element is an image pickup device that has been generally used from the past,
That is, compared with an image pickup apparatus which converts an optical image of a subject formed on a photoelectric conversion unit of an image pickup device such as an image pickup tube or a solid-state image pickup device by an image pickup lens into a video signal, high image quality can be easily achieved. A high-resolution reproduced image can be obtained.

That is, in an image pickup apparatus capable of generating a video signal capable of reproducing a high-quality / high-resolution reproduced image, in an image pickup apparatus using an image pickup tube as an image pickup element, Since there is a limit to miniaturization, it is not possible to expect high resolution by miniaturizing the electron beam diameter, and the target capacity of the image pickup tube increases corresponding to the target area. It is not possible to realize high resolution due to, and, for example, in the case of a moving image pickup device, the frequency band of the video signal is several tens of MHz due to the higher resolution.
It is difficult to generate a video signal capable of reproducing a high-quality / high-resolution reproduced image by the image pickup device due to the fact that it becomes a problem in terms of S / N due to the frequency of several hundred MHz or more. Is.

The above points will be specifically described as follows. In order to generate a video signal capable of reproducing a high-quality and high-resolution reproduced image by an image pickup device in which an image pickup tube is used as an image pickup element, the electron beam diameter in the image pickup tube is made small or a large target is used. Although it may be possible to use an electron beam with a small area, there is a limit to the miniaturization of the electron beam diameter of the image pickup tube due to the performance of the electron gun of the image pickup tube and the structure of the focusing system. There is a limit to the increase in resolution by increasing the size of the image pickup lens, and if an image pickup lens with a large image pickup size is used and high resolution is to be obtained by increasing the area of the target, the image pickup tube will increase due to the increase in the target area. The high-frequency signal component in the output signal of the image pickup tube decreases due to the increase in the target capacitance of the image pickup tube, and the S / N of the image pickup tube output signal decreases significantly. Depending imaging device using a pipe is not possible to satisfactorily generate a video signal as capable of reproducing the high image quality and high resolution of the reproduced image.

Further, in order to reproduce a high-quality and high-resolution reproduced image by an image pickup apparatus using a solid-state image pickup element as an image pickup element, it is necessary to use a solid-state image pickup element having a large number of pixels. Many solid-state image pickup devices have a high clock frequency for driving them (for example, the frequency of a clock for driving a solid-state image pickup device in the case of a video camera is several hundred MHz), and are also targeted for driving. Since the capacitance value of the circuit that is used increases with the increase in the number of pixels, such a solid-state imaging device is practical in view of the current limit of the clock frequency of the solid-state imaging device being 20 MHz. It cannot be configured as a thing.

As described above, the conventional image pickup apparatus cannot generate a video signal capable of reproducing a high-quality / high-resolution reproduced image satisfactorily due to the existence of the image pickup element indispensable for its configuration. However, in the image pickup apparatus using the light-to-light conversion element, there is no problem in the conventional image pickup apparatus described above, and it is possible to easily generate a video signal capable of obtaining a reproduced image of high image quality and high resolution.

For an image pickup device configured using a light-to-light conversion element, refer to "Image pickup device" (Japanese Patent Application No. 61-313333) filed by the applicant company on December 30, 1986. .

In the light-to-light conversion element used in the image pickup apparatus described above with reference to FIG. 4, depending on the intensity distribution of the applied electric field among the plurality of optical members required for its construction. Lithium niobate as an optical member that changes the state of light by the property that the phase difference between an ordinary ray and an extraordinary ray passing through the optical member changes according to the electric field strength applied to the crystal. An anisotropic crystal such as a single crystal was used.

However, an anisotropic crystal such as a lithium niobate single crystal has a phase difference between an ordinary ray and an extraordinary ray passing through the crystal,
Not only does it change according to the strength of the electric field applied to the anisotropic crystal, but it also changes according to the thickness of the anisotropic crystal, as is well known. In the image pickup device having the configuration shown in FIG. 4, which uses a light-to-light conversion element in which an anisotropic crystal such as a lithium niobate single crystal is used as an optical member that changes the state of
When the thickness of the optical member using an anisotropic crystal such as the lithium niobate single crystal used in the light-to-light conversion element is not made constant with high accuracy,
As described above, the reproduced image read from the light-to-light conversion element has shading corresponding to the uneven thickness of the optical member 9 using the anisotropic crystal such as the lithium niobate single crystal. .

FIG. 6 (a) is a light-to-light conversion element in which an anisotropic crystal such as a lithium niobate single crystal is used as the optical member 9 for changing the state of light according to the intensity distribution of the applied electric field. In the image pickup apparatus shown in FIG. 4 configured by using PPC, the thickness of the optical member 9 using an anisotropic crystal such as the lithium niobate single crystal used in the light-to-light conversion element PPC described above is , As shown in FIG. 7, when the thickness unevenness is d in the X direction in the figure,
FIG. 9 is a waveform example diagram of a signal obtained by scanning the optical member 9 using an anisotropic crystal such as a lithium niobate single crystal in the X direction by the reading light RL to read a charge image. FIG. 6 (c) illustrates the waveform of the signal corresponding to the original charge image.

As can be seen from (a) and (c) of FIG. 6, the light-to-light conversion element P
The thickness of the optical member 9 using an anisotropic crystal such as a lithium niobate single crystal used in a PC has a thickness of d in the X direction as illustrated in FIG. In the case of unevenness, one horizontal line obtained by scanning the optical member 9 using an anisotropic crystal such as a lithium niobate single crystal in the X direction by the reading light RL to read a charge image. The signal in the scanning period (1H) is different from the original signal corresponding to the charge image shown in FIG.
In the signal corresponding to the original charge image shown in (c), d in the X direction in an anisotropic crystal such as a lithium niobate single crystal used in the photo-to-photo conversion device PPC is used.
A signal of the sum of the thickness unevenness and the signal generated corresponding to it,
That is, the signal has a waveform as shown in FIG. 6 (a).

The imaging device shown in FIG. 5 is an imaging device configured to solve the above-mentioned problems in the imaging device shown in FIG. 4, that is, at least a photoconductive layer member between two transparent electrodes. And a dielectric mirror having wavelength selectivity that allows light in the wavelength range of the read light to be transmitted while transmitting light in the wavelength range of the erase light, and the state of the light depending on the intensity distribution of the applied electric field. The light from the object is made incident on the photoconductive layer member side of the light-to-light conversion element formed by laminating the light-modulation material layer member to change the light-to-light conversion element to generate a charge image corresponding to the optical image of the object. Means, means for reading out a charge image corresponding to the optical image of the subject as an optical image by the reading light incident on the light-to-light converting element from the light modulation material layer member side of the light-to-light conversion element, and the subject. Paired with the optical image of In the image pickup apparatus including the charge image erasing unit, the state of light changes depending on the intensity distribution of the applied electric field in the incident light path of the reading light with respect to the light-to-light conversion element to which the optical image of the subject is given. An optical member for shading correction including a changing light modulating material layer member is provided, and a reproduced optical image is formed in correspondence with the undesired birefringence state of the light modulating material layer member in the light-to-light conversion element. 1 shows an embodiment of an image pickup apparatus that is configured to include a correction signal generation unit that gives a shading correction electric field to the shading correction optical member that can correct shading of light that occurs. In the image pickup apparatus shown in FIG. 5, it is possible to prevent shading from occurring in the reproduced image, which has been a problem in the image pickup apparatus shown in FIG. .

The reason why shading does not occur in a reproduced image in the image pickup apparatus shown in FIG. 5 is based on the following configuration principle and operation principle.

That is, in the image pickup apparatus shown in FIG. 5, an optical crystal that uses an anisotropic crystal such as a lithium niobate single crystal as the optical member 9 that changes the state of light according to the intensity distribution of the applied electric field. The conversion element PPC is used, and the thickness of the optical member 9 using an anisotropic crystal such as the lithium niobate single crystal used in the light-to-light conversion element PPC is shown in FIG. As shown in the drawing, since the thickness unevenness is equal to d in the X direction in the figure, the optical member 9 using an anisotropic crystal such as a lithium niobate single crystal is read by the reading light RL. When the charge image is read by scanning in the X direction, the read-out of the charge image in the photo-to-photo conversion element PPC is performed when a signal having a signal waveform as shown in FIG. 6 (a) is obtained. When the reading light RL used for The mode of intensity change on the axis is set in correspondence with the mode of thickness change of the optical member 9 using an anisotropic crystal such as a lithium niobate single crystal used in the light-to-light conversion element PPC. By using the reading light RL, an anisotropic crystal such as a lithium niobate single crystal having a thickness unevenness of d in the X direction in the figure is used as illustrated in FIG. When the charge image is read by scanning the optical member 9 with the reading light RL in the X direction in the figure, the charge shown in (c) of FIG. 6 as a signal for one horizontal scanning period (1H). The original signal corresponding to the image is obtained.

FIG. 6 (b) shows anisotropy such as a lithium niobate single crystal having a thickness unevenness of d in the X direction in the figure as illustrated in FIG. 7 by the reading light RL. As a signal of one horizontal scanning period (1H) which is generated when the charge image is read by scanning the optical member 9 using crystals with the reading light RL in the X direction in the figure, (c) of FIG. In order to obtain a signal with a signal waveform corresponding to the charge image shown in
For changing the thickness of the optical member 9 using an anisotropic crystal such as a lithium niobate single crystal used in the light-to-light conversion element PPC, and for reading out a charge image in the light-to-light conversion element PPC. The reading supplied to the light-to-light conversion element PPC to which the optical image of the subject is to be given so that the change mode of the intensity of the reading light RL used for the above on the time axis corresponds. A shading correction electric field to be supplied to the shading correction optical member SCA including a light modulation material layer member whose light state changes according to the intensity distribution of the applied electric field provided in the incident optical path of the light RL ( Shading correction signal voltage)
7 shows an example of a change mode on the time axis of.

In FIG. 5, O is a subject, L is an imaging lens, BS1,
BS2 is a beam splitter, PSr is a light source for reading light,
PSe is a light source for erasing light, PLP is a polarizing plate, PD is a photodetector, and SCA is configured to include a light modulation material layer member whose light state changes according to the intensity distribution of an applied electric field. The shading correction optical member SCA is a read light R for the light-to-light conversion element PPC to which an optical image of a subject is to be given.
It is provided in the incident light path of L.

As the above-mentioned shading correction optical member SCA, a lateral modulator (having the form shown in FIG. 5) having a configuration in which electrodes are positioned in a direction orthogonal to the light incident surface. May be used, or a vertical modulator having a configuration in which electrodes are arranged in a direction parallel to the light incident surface may be used.

The electrodes 13, 14 of the shading correction optical member SCA, which is configured to include the light modulation material layer member whose light state changes according to the intensity distribution of the applied electric field, have the optical modulation in the light-to-light conversion element PPC. Of an anisotropic crystal such as a lithium niobate single crystal used as a material layer member due to the uneven birefringence that occurs in the anisotropic crystal and A shading correction voltage capable of correcting shading is supplied from the correction signal generation unit CSG, and is used as a light modulation material layer member in the light-to-light conversion element PPC between the electrodes 13 and 14 of the shading correction optical member SCA. Reproduction light corresponding to an undesired birefringence state generated in an anisotropic crystal based on uneven thickness of an anisotropic crystal such as a lithium niobate single crystal Shading correction electric field can be corrected shading of the light generated in the image is to be formed.

The shading correction voltage to be generated by the correction signal generation unit CSG is, for example, the light-to-light conversion element PP.
The state where there is no charge image pattern in C, that is, the read light R in the light-to-light conversion element PPC when there is no signal after the erasing operation
Information of a reproduced image obtained by performing the read operation with L incident thereon is stored as initial information, and the shading correction signal voltage is generated by using the information, or in a conventional general imaging device. The shading correction voltage may be generated by applying the same means as the case where various correction signals are generated by various correction signal generation means.

In addition, the shading correction optical member SCA electrode 13,
A liquid crystal material layer member whose light state changes according to the intensity distribution of the applied electric field to be provided between
Any material may be used as long as it has a predetermined function, such as a lithium niobate single crystal.

PDEF in FIG. 5 is an optical deflector, and this optical deflector PDEF is configured to have a function of vertically and horizontally deflecting the laser light beam emitted from the above-mentioned shading correction optical member SCA in a predetermined manner. What is used is being used.

In the image pickup apparatus having the configuration illustrated in FIG. 5 configured by using the light-to-light conversion element PPC, the optical image of the object O is written by the image pickup lens L to the light-to-light conversion element PPC as the writing light to the glass plate. It is incident from the 1 side.

In the imaging device having the configuration illustrated in FIG. 5, the transparent electrodes 3 and 4 in the light-to-light conversion element PPC in the writing mode and the reading mode are
Since the voltage of the power source 10 is applied through the changeover switch SW in the state where the movable contact is switched to the fixed contact WR side, the light corresponding to the optical image of the subject O is written as the writing light via the imaging lens L. In the light-to-light conversion element PPC provided on the glass plate 1 side, as described above with reference to FIG. 3, the photoconductive layer 7 and the optical member 8R (the light in the wavelength range of the read light RL) are reflected. , An optical member 8 having wavelength selectivity capable of transmitting light in the wavelength range of the erasing light EL.
R), a charge image corresponding to the optical image by the incident light that has reached the photoconductive layer 7 (in FIG. 5, for the optical image of the object O in the V shape in the light-to-light conversion element PPC). At the boundary surface between the photoconductive layer 7 and the optical member 8R, an inverted charge image (shown as an inverted charge image) appears.

As described above, the optical information is written by the writing light from the glass plate 1 side, and the photoconductive layer 7 of the light-to-light conversion element PPC is formed.
And the optical member 8R (optical member 8R having wavelength selectivity capable of reflecting light in the wavelength range of the reading light RL and transmitting light in the wavelength range of the erasing light EL) are affected by incident light. From the light source PSr of the reading light in the state where the voltage of the power source 10 is applied through the changeover switch SW between the transparent electrodes 3 and 4 in the light-to-light conversion element PPC in the state where the charge image corresponding to the optical image is generated. The emitted coherent light read-out light RL is transmitted through the beam splitter BS1 and then includes an optical modulation material layer member whose light state changes according to the intensity distribution of the applied electric field. It is incident on the member SCA.

Electrode 1 of the above-mentioned optical member SCA for shading correction
Nos. 3 and 14 are undesired ones generated in anisotropic crystals due to uneven thickness of anisotropic crystals such as lithium niobate single crystal used as a light modulating material layer member in the light-to-light conversion element PPC. Since the shading correction voltage capable of correcting the shading of the light amount occurring in the reproduced optical image corresponding to the birefringence state is supplied from the correction signal generation unit CSG, the laser light emitted from the shading correction optical member SCA is After being deflected in a predetermined manner by the optical deflector PDEF, it enters the beam splitter BS2, where it is reflected toward the light-to-light conversion element PPC and enters from the glass plate 2 side of the light-to-light conversion element PPC. Then, as already described with reference to FIG. 3, the read light RL incident on the glass plate 2 side is transparent electrode 4 → lithium niobate single Crystal 9 → Optical member 8R (optical member 8R having wavelength selectivity capable of reflecting light in the wavelength range of the reading light RL and transmitting light in the wavelength range of the erasing light EL) → go.

Next, the read light RL is reflected by the optical member 8R having a wavelength selectivity that allows the light in the wavelength range of the read light to be reflected and the light in the wavelength range of the erase light to be transmitted to the glass plate 2 side. It returns as reflected light.

As described above, the light-to-light conversion element P in which the reading light RL reciprocates
The refractive index for an ordinary ray and an extraordinary ray of an anisotropic crystal such as a lithium niobate single crystal used as a light modulating material layer member in a PC is lithium niobate due to the electro-optical effect of the lithium niobate single crystal 9. It changes in different states depending on the electric field strength applied to the single crystal 9, but when the thickness of the lithium niobate single crystal 9 is non-uniform, it occurs in the anisotropic crystal due to the unevenness of the thickness. Although an undesired birefringence state occurs, in the imaging device shown in FIG. 5, the undesired birefringence state occurring in the anisotropic crystal can be corrected based on the thickness unevenness of the lithium niobate single crystal 9. As the read light RL that travels back and forth through the lithium niobate single crystal used as the light modulation material layer member in the light-to-light conversion element PPC, it is possible to prevent light shading in the reproduced optical image. Since on purpose so as corrected by the shading correcting optical member SCA I previously is to be performed, in the imaging apparatus of the fifth depicted can so as not to cause shading in the reproduction optical image.

The light of the reproduced optical image is transmitted through the beam splitter BS2 and the polarizing plate PLP and given to the photodetector PD, so that a video signal corresponding to the optical image of the object O is output from the photodetector PD. Will be output.

In the image pickup apparatus shown in FIG. 5 as well, similar to the image pickup apparatus shown in FIG. 4 described above, it is necessary to write and read images of different subjects for each predetermined time length on the time axis to generate a video signal. However, as described above, in order to write and read images of different subjects at predetermined time lengths on the time axis, in order to read and write images of the different objects, the predetermined time on the time axis is set. Before the optical image of a new subject is written for each length, it is necessary to erase the charge image corresponding to the optical image that has been written so far.

Then, the erasing operation in the image pickup device is performed during a predetermined time period before writing new optical images one after another on the time axis, which is an image output from the photodetector PD. Corresponding to the vertical blanking period in the video signal output from the photodetector PD, as described above with reference to FIG. The movable contact of the changeover switch SW is changed to the fixed contact E side by the changeover control signal supplied to the input terminal 11 of the changeover control signal in the changeover switch SW connected between the terminals 5 and 6 of the conversion element, The transparent electrodes 3 and 4 are electrically short-circuited to make the transparent electrodes 3 and 4 have the same potential, and the photoconductive layer 7
The erasing light EL is emitted from the light source PSe of the erasing light, and the erasing light EL is emitted from the glass plate 2 side of the light-to-light conversion element PPC via the beam splitters BS1 and BS2. Make it incident.

As described above with reference to FIG. 3, the erasing light EL incident on the glass plate 2 side of the light-to-light conversion element is the glass plate 2 → transparent electrode 4 → lithium niobate single crystal 9 → optical member 8R (readout). An optical member 8R having a wavelength selectivity capable of reflecting light in the wavelength range of light and transmitting light in the wavelength range of erasing light → reaches the photoconductive layer 7 by a route such as the photoconductive layer 7. Then, the erasing light EL reduces the electric resistance value of the photoconductive layer 7, and the charge image formed on the boundary surface between the photoconductive layer 7 and the optical member 8R is erased.

(Effects of the Invention) As is apparent from the above description, according to the present invention, the transparent electrode, the photoconductive layer, the light in the wavelength range of the reading light, and the light in the wavelength range of the erasing light are reflected. An optical member having wavelength selectivity that allows transmission, and an optical member that changes the state of light according to the intensity distribution of the applied electric field,
A light-to-light conversion element in which a transparent electrode is laminated, and at least a photoconductive layer member between two transparent electrodes, which reflects light in the wavelength range of read light and transmits light in the wavelength range of erase light. Photoconductive layer member side in a photo-to-optical conversion element in which a dielectric mirror having such wavelength selectivity and a light modulation material layer member that changes the state of light according to the intensity distribution of an applied electric field are laminated. Means for injecting light from the subject into the light-to-light conversion element to generate a charge image corresponding to the optical image of the subject, and reading the light-to-light conversion element from the light modulation material layer member side of the light-to-light conversion element An image pickup device provided with means for reading out a charge image corresponding to the optical image of the subject as an optical image by light, and a means for erasing the charge image corresponding to the optical image of the subject, and two transparent electrodes. Less during A photoconductive layer member also causes reflected light in a wavelength range of the reading light, a dielectric mirror having wavelength selectivity such as may not transmit light in the wavelength region of the erasing light,
Light-to-light conversion element in which light from a subject is incident on the photoconductive layer member side of a light-to-light conversion element formed by laminating a light modulation material layer member that changes the state of light according to the intensity distribution of an applied electric field Means for generating a charge image corresponding to the optical image of the subject, and the read light incident on the light-to-light converting element from the light modulation material layer member side of the light-to-light converting element, the charge corresponding to the optical image of the object described above. In an image pickup apparatus comprising means for reading an image as an optical image and means for erasing the charge image corresponding to the optical image of the subject, read light for the light-to-light conversion element to which the optical image of the subject is to be given. In the incident optical path of, the shading correction optical member including the light modulation material layer member whose state of light changes according to the intensity distribution of the applied electric field is provided, and the light-to-light conversion described above is performed. A correction signal generator that gives a shading correction electric field to the shading correction optical member so as to correct the shading of light generated in the reproduced optical image corresponding to the undesired birefringence state of the light modulation material layer member in the child. Therefore, the light-to-light conversion element of the present invention is an image pickup device having a configuration in which an image pickup optical system is required to be provided on the side where the write light WL is incident, and The present invention can be easily applied to a device having a configuration mode in which it is difficult to provide an erasing light incident device on the side where the WL is incident. A light-to-light conversion device which can satisfactorily solve the problems in the light-to-light conversion device and which includes an optical member that changes the state of light according to the intensity distribution of the applied electric field. When an anisotropic crystal such as a lithium niobate single crystal is used as an optical member that changes the state of light in accordance with the intensity distribution of an applied electric field, the anisotropic crystal is The phase difference between the ordinary ray and the extraordinary ray passing through does not only change according to the electric field strength applied to the anisotropic crystal as described above, but also changes according to the thickness of the anisotropic crystal as is well known. Therefore, if the thickness of the anisotropic crystal used in the light-to-light conversion element is not made to be highly accurate and constant as described above, the reproduced image read from the light-to-light conversion element is shaded. However, in the image pickup apparatus of the present invention, an undesired birefringence state generated in the anisotropic crystal is corrected based on the unevenness of the thickness of the anisotropic crystal to shade the reproduced optical image. Does not occur For correcting shading, the light modulation material layer member whose light state changes according to the intensity distribution of the applied electric field is included in the incident light path of the reading light with respect to the light-to-light conversion element PPC. Since the optical member SCA is installed and the shading correction optical member SCA is used to correct the reading light RL so as not to cause light shading in the reproduced optical image, the reproduced optical image is corrected. It is possible to prevent shading.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of the light-to-light conversion element of the present invention,
FIG. 2 is a characteristic curve example diagram showing an example of wavelength selection characteristics of an optical member having a wavelength selectivity capable of reflecting light in the wavelength range of read light and transmitting light in the wavelength range of erase light. FIG. 1 is a block diagram for explaining the operation of the light-to-light conversion element of one embodiment of the present invention shown in FIG. 1, and FIGS. 4 and 5 are constructed using the light-to-light conversion element of one embodiment of the present invention. FIG. 6 is a perspective view showing a schematic configuration of each different image pickup device, FIG. 6 is a waveform diagram for explaining the operation, FIG. 7 is a side view of an optical member for explaining the problem, and FIG. 8 is a conventional optical-to-optical conversion element. FIG. 3 is a block diagram of an example. 1, 2 ... Glass plate, 3, 4 ... Transparent electrode, 5, 6 ... Terminal,
Reference numeral 7 ... Photoconductive layer, 8 ... Dielectric mirror, 8R ... Optical member having wavelength selectivity capable of reflecting light in the wavelength range of read light and transmitting light in the wavelength range of erase light, 9 ... Optical member for changing the state of light according to the intensity distribution of the generated electric field, 10 ... Power source, 11 ... Terminal, 12 ... Light shielding layer, W
L ... writing light, RL ... reading light, EL ... erasing light, SW ...
Changeover switches, 13, 14 ... Electrodes, SCA ... Shading correction optical member including an optical modulation material layer member whose light state changes according to the intensity distribution of the applied electric field,
PPC ... Optical-to-optical conversion element, CSG ... Correction signal generator, P
DEF ... Optical deflector, L ... Imaging lens, PLP ... Polarizing plate,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Den Asakura, 12-12 Moriya-cho, Kanagawa-ku, Yokohama, Kanagawa Prefecture, Japan Victor Company of Japan, Ltd. (72) Masato Furuya 3--12, Moriya-cho, Kanagawa-ku, Yokohama Address within Victor Company of Japan (56) Reference JP-A-54-94058 (JP, A) JP-A-41-60243 (JP, A) JP-A-55-74514 (JP, A)

Claims (3)

[Claims] 1. A transparent electrode, a photoconductive layer, and an optical member having a wavelength selectivity capable of reflecting light in the wavelength range of read light and transmitting light in the wavelength range of erase light. Optical-to-optical conversion element formed by stacking a transparent electrode and an optical member that changes the state of light according to the intensity distribution of the electric field 2. At least a photoconductive layer member between two transparent electrodes and a dielectric having a wavelength selectivity capable of reflecting light in the wavelength range of read light and transmitting light in the wavelength range of erase light. The light from the subject is made incident on the photoconductive layer member side of the light-to-light conversion element in which the body mirror and the light modulation material layer member that changes the state of light according to the intensity distribution of the applied electric field are laminated. An optical image of the subject described above by means for causing the light-to-light conversion element to generate a charge image corresponding to the optical image of the subject and read-out light incident on the light-to-light conversion element from the light modulation material layer member side of the light-to-light conversion element. An image pickup device comprising means for reading out an electric charge image corresponding to the optical image as an optical image, and means for erasing the electric charge image corresponding to the optical image of the subject described above. 3. At least a photoconductive layer member between two transparent electrodes, and a dielectric having wavelength selectivity such that light in the wavelength region of read light is reflected and light in the wavelength region of erase light is transmitted. The light from the subject is made incident on the photoconductive layer member side of the light-to-light conversion element in which the body mirror and the light modulation material layer member that changes the state of light according to the intensity distribution of the applied electric field are laminated. An optical image of the subject described above by means for causing the light-to-light conversion element to generate a charge image corresponding to the optical image of the subject and read-out light incident on the light-to-light conversion element from the light modulation material layer member side of the light-to-light conversion element. In an image pickup device comprising a means for reading out a charge image corresponding to the optical image as an optical image and a means for erasing the charge image corresponding to the optical image of the subject, light-to-light conversion to which the optical image of the subject should be given. To the element In the incident light path of the reading light, a shading correction optical member including a light modulation material layer member whose light state changes according to the intensity distribution of the applied electric field is provided, and in the light-to-light conversion element described above. A shading correction electric field for correcting shading of light generated in a reproduced optical image corresponding to an undesired birefringence state of the light modulation material layer member; Imaging device