JPH0648330B2 - Light-to-light conversion element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical device suitable for an image pickup device, an optical writing projection device, and the like.
The present invention relates to a light conversion element.

(Prior Art) Examples of light-to-light conversion elements configured to input an optical image and output the optical image also include a liquid crystal optical modulator, a photoconductive Pockels effect element, and a microchannel. Modulators such as a spatial light modulator, or elements having various configurations such as an element formed by using a photochromic material are, for example, an element for optical parallel processing of an optical writing projection device or an optical computer. , Has been attracting attention as an element for recording an image, and the applicant company has proposed a high-resolution image pickup device using a light-light conversion element.

FIG. 5 is a side sectional view showing a configuration example of a conventional light-light converting element. In the light-light converting element shown in FIG. 7, 1 and 2 are glass plates, and 3 and 4 are transparent electrodes. , 5, 6, 1
1 is a terminal, 7 is a photoconductive layer member, 12 is a light shielding layer, 8 is a dielectric mirror, 9 is an optical member that changes the state of light according to the intensity distribution of an applied electric field (light modulation material layer member ... (Nematic liquid crystal layer), WL is writing light, RL is reading light,
EL is the 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,
Both ends of an optical member 9 (for example, a nematic liquid crystal layer which may be a nematic liquid crystal layer, and may be described as a nematic liquid crystal layer 9 in the following description) that changes the state of light according to the intensity distribution of an applied electric field. An electric field is applied between them, and the writing light WL is made incident from the glass plate 1 side of the light-light conversion element, and the incident writing light WL is transmitted to the glass plate 1 and the transparent electrode 3. When reaching the photoconductive layer member 7, the electric resistance value of the photoconductive layer member 7 changes corresponding to the optical image by the incident light reaching the photoconductive layer member 7.
At the boundary surface between the photoconductive layer member 7 and the light shielding layer 12, a charge image corresponding to the optical image due to the incident light reaching the photoconductive layer member 7 is generated.

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 are provided for the photoconductive layer member 7 described above. An electric field having an intensity distribution corresponding to an optical image by incident light is applied to the nematic liquid crystal layer 9 provided in series with the mirror 8 and the like, and the liquid crystal in the nematic liquid crystal layer 9 has an optical axis of its molecule. When the read light RL is projected on the glass plate 2 side because the light is no longer parallel to the polar plate, reflection in a state including image information according to the electric field strength applied to the liquid crystal layer 9 due to the electro-optical effect of the nematic liquid crystal. Light is generated, and 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
In the read light RL which travels as shown in 2, light not reflected by the dielectric mirror 8 is shielded by the light shielding layer 12 so as not to travel to the photoconductive layer member 7 side, so that the read light RL is Is not projected on the glass plate 2 side, the electric resistance value of the photoconductive layer member 7 does not change. Therefore, the projection of the reading light RL causes the photoconductive layer member 7 and the light shielding layer 12 to be separated from each other. The charge image generated on the boundary surface in correspondence with the optical image by the incident light is not changed.

By the way, in the light-to-light conversion element having the structure as shown in the fifth illustration, when the information written in the light-to-light conversion element by the writing light WL is erased, the changeover control signal in the above-mentioned changeover switch SW is used. A changeover control signal is supplied to the input terminal 11 of the switch SW to change the movable contact of the changeover switch SW to the fixed contact E.
To the side where the writing light WL is incident after the electric potentials of the terminals 5 and 6 in the light-to-light conversion element are made the same so that an electric field is not generated between the transparent electrodes 3 and 4. By inputting the erasing light EL having a uniform intensity distribution from the 1 side, the erasing light EL described above is given to the photoconductive layer member 7 through the glass plate 1 and the transparent electrode 3, and the electrical conductivity of the photoconductive layer member 7 is increased. The electric charge image generated on the boundary surface between the photoconductive layer member 7 and the light shielding layer 12 is erased in a state where the resistance value is reduced. In this way, the erase light must be incident from the incident side of the write light. That is, the light-to-light conversion element, for example, an image pickup apparatus having a configuration in which it is necessary to provide an image pickup optical system on the side where the writing light WL is incident, and the writing light WL is incident. Provide an erasing light injection device on the side where It becomes a big problem when the like used in the device configuration aspect of the difficult circumstances.

Therefore, as a light-to-light conversion element capable of solving the above-mentioned problems, a light-to-light conversion element having a structure as illustrated in FIG. 6, that is, a transparent electrode, a photoconductive layer member, and a read-out device. A reflecting mirror member having a wavelength selectivity capable of reflecting light in the wavelength region of light and transmitting light in the wavelength region of erasing light, and changing the state of light according to the intensity distribution of the applied electric field A light-to-light conversion element is proposed, which is formed by laminating an optical member and a transparent electrode.

In FIG. 6, 1 and 2 are glass plates, 3 and 4 are transparent electrodes,
Reference numerals 5 and 6 are terminals, 7 is a photoconductive layer member, and 8R is a dielectric having wavelength selectivity capable of reflecting light in the wavelength range of read light and transmitting light in the wavelength range of erase light. As the dielectric mirror 8R, for example, a dielectric mirror 8R configured by a dichroic filter having a multilayer film of a SiO2 thin film and a TiO2 thin film is used.

Reference numeral 9 denotes an optical member that changes the state of light according to the intensity distribution of the applied electric field (optical modulation material layer member ... For example, an electro-optical effect crystal such as lithium niobate single crystal or bismuth silicate oxide, or a nematic. Although it is an optical member composed of a liquid crystal layer, it may be simply described as lithium niobate single crystal 9 in the following description), in which WL is writing light, RL is reading light, EL indicates the erasing light.

FIG. 7 is a curve diagram exemplifying the wavelength selectivity of the dielectric mirror 8R having wavelength selectivity capable of reflecting the light in the wavelength range of the read light and transmitting the light in the wavelength range of the erasing light. 7 shows that the dielectric mirror 8R having the characteristics illustrated in FIG. 7 is configured as an optical low pass filter. The dielectric mirror 8R described above, for example, is an optical high pass filter. It may be configured as having the characteristics of an optical filter, the characteristics of an optical bandpass filter, and the characteristics of an optical bandstop filter.

If the wavelength selection characteristic of the dielectric mirror 8R in the light-to-light conversion element is as shown in FIG. 7, the read light to be incident on the light-to-light conversion element is the light transmittance of the dielectric mirror 8R. Light in a low wavelength region (for example, light having a wavelength λ1 in FIG. 7) is used, and as erase light to be incident on it, light in a wavelength region having a high light transmittance in the dielectric mirror 8R (for example, FIG. 7). In the light-to-light conversion element shown in FIG. 6, it is possible to cause the erasing light to enter from the incident side of the reading light by using the light of the middle wavelength λ2).

When optical information is written in the light-to-light conversion element having the structure shown in FIG. 6, the power source 10 and the changeover switch connected to the terminals 5 and 6 of the light-to-light conversion element. The changeover switch SW of the circuit consisting of SW is controlled by the changeover control signal supplied to the input terminal 11 of the changeover control signal to bring the movable contact of the changeover switch SW to the fixed contact WR side, and the above-mentioned operation is performed. The voltage of the power supply 10 is applied between the transparent electrodes 3 and 4 so that an electric field is applied between both ends of the photoconductive layer member 7, and the writing light WL is incident from the glass plate 1 side of the light-to-light conversion element. By doing so, the optical information is written to the light-light conversion element.

That is, as described above, when the writing light WL that has entered the light-to-light conversion element passes through the glass plate 1 and the transparent electrode 3 and reaches the photoconductive layer member 7, the electric resistance value of the photoconductive layer member 7 is changed to that. The charge image corresponding to the optical image formed by the incident light reaching the photoconductive layer member 7 is formed on the boundary surface between the photoconductive layer member 7 and the dielectric mirror 8R because it changes corresponding to the optical image formed by the incident light. Occurs.

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

That is, as described above, the incident light reaching the photoconductive layer member 7 is formed on the boundary surface between the photoconductive layer member 7 and the dielectric mirror 8R in the light-to-light conversion element in which the optical information is written by the incident light. Since a charge image corresponding to the optical image due to is generated, the dielectric mirror 8R is formed on the photoconductive layer member 7 described above.
The optical member 9 (for example, the lithium niobate single crystal 9) provided in series is also in a state in which an electric field having an intensity distribution corresponding to the optical image by the incident light is applied.

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 member 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. Dielectric mirror 8 for 7
The refractive index of the lithium niobate single crystal 9 provided in series relationship with R is the same as that of the photoconductive layer member 7 in the light-to-light conversion element due to the writing of optical information by the incident light described above.
And the dielectric mirror 8R at the interface between the dielectric mirror 8R and the dielectric mirror 8R are changed according to the optical image formed by the incident light reaching the photoconductive layer member 7 and the corresponding charge 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 → dielectric mirror 8R. → Proceed as follows.

The read light RL is reflected by the dielectric mirror 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. Although returning as light, the refractive index of the lithium niobate single crystal 9 changes according to the electric field due to the electro-optical effect, so that the reflected light of the read light RL is lithium niobate due to the electro-optical effect of the lithium niobate single crystal 9. Image information corresponding to the intensity distribution of the electric field applied to the single 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 readout light RL projected from the glass plate 2 side in the above-described reproducing operation is directed toward the photoconductive layer member 7 as in the transparent electrode 4 → lithium niobate single crystal 9 → dielectric mirror 8R →, as described above. The read-out light RL is reflected by the dielectric mirror 8R before reaching the photoconductive layer member 7, so that the lithium niobate single crystal 9 → transparent electrode 4 → glass. Since the optical path is the same as that of the plate 2, the reading light RL does not adversely affect the charge image due to the incident light written to the photoconductive layer member 7.

As described above, in the light-light conversion element shown in FIG. 6, the writing operation is performed by making the writing light WL incident from the glass plate 1 side, and the optical operation is made by making the reading light RL incident on the glass plate 2 side. The image is reproduced.

Next, when erasing the information written in the light-to-light conversion element shown in FIG. 6, the switching connected between the terminals 5 and 6 of the light-to-light conversion element shown in FIG. The movable contact of the changeover switch SW is fixed to the fixed contact E by the changeover control signal supplied to the input terminal 11 of the changeover control signal in the switch SW.
After that, the transparent 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 across the photoconductive layer member 7. The erasing light EL is made incident from the glass plate 2 side of the light-light conversion element.

As described above, the erasing light EL incident on the glass plate 2 side of the light-to-light conversion element is as in glass plate 2 → transparent electrode 4 → lithium niobate single crystal 9 → dielectric mirror 8R → photoconductive layer member 7. The photoconductive layer member 7 is reached by a route and the erasing light EL
Thus, the electric resistance value of the photoconductive layer member 7 is reduced, and the charge image formed on the boundary surface between the photoconductive layer member 7 and the dielectric mirror 8R is erased.

In this way, in the light-to-light conversion element shown in FIG. 6, the charge image formed on the boundary surface between the photoconductive layer member 7 and the dielectric mirror 8R at the time of the writing operation becomes the read light RL in the light-to-light conversion element. Since erasing is performed by the erasing light EL that is incident on the light-to-light conversion element from the incident side, imaging having a configuration in which it is necessary to provide an imaging optical system on the side on which the writing light WL is incident. Device, other, writing light W
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 on which L is incident, and can satisfactorily solve the above-mentioned conventional problems. .

(Problems to be Solved by the Invention) By the way, in the already proposed light-to-light conversion element, the light-shielding layer 1 in the light-to-light conversion element having the structure illustrated in FIG.
2 and the dielectric mirror 8 and the wavelength selectivity such that the light in the wavelength range of the read light in the light-to-light conversion element having the configuration illustrated in FIG. 6 can be reflected and the light in the wavelength range of the erase light can be transmitted. A continuous planar dielectric mirror was used as the dielectric mirror 8R (for example, a dichroic filter including a multilayer film of a thin film of SiO2 and a thin film of TiO2), but as described above, it is two-dimensional. If a continuous planar member on which a different charge image is to be formed is an electrically good conductor, it is natural that the entire surface of the member instantly becomes the same potential, so the two-dimensional charge image is scanned and the It is impossible to read as a serial signal on the axis, and also when the electric resistance value in the spreading direction of the surface of the continuous planar member is not necessarily sufficiently large, Good for reading high-definition signals It is difficult to perform in.

In a continuous planar member used in a light-to-light conversion element, for example, when looking at a dielectric mirror, the electric resistance value in the spreading direction of the surface of the dielectric mirror composed of a multilayer film is higher than that of a metal film. Even if it has a resistance value, it is not infinite. Therefore, for example, the portion of the light modulation material layer member 9 and the dielectric mirror 8R in the light-to-light conversion element shown in FIG. 6 is equivalent to that shown in FIG. It will be exemplified by a circuit.

In FIG. 4, R, R ... Are electrical resistances in the direction in which the surface spreads in the dielectric mirror 8R made of a planar multilayer film, and C, C ... Compose a light-to-light conversion element. The electrostatic capacitance value of the portion of the light modulation material layer member 9 and Co indicate the electrostatic capacitance of the photoconductive layer member 7, respectively.

As can be easily understood by referring to the equivalent circuit shown in FIG. 4, a light modulation material layer member in a light-light conversion element using a dielectric mirror composed of a continuous planar multilayer film as a reflecting mirror. The potential distribution generated in the portion 9 corresponding to the optical image of the object is such that the surface potential of the dielectric mirror gradually averages according to the time constant determined by the resistance R and the capacitance C shown in FIG. Since the resolution of the light-to-light conversion element decreases with the lapse of time, the improvement measures have been required.

(Means for Solving Problems) The present invention provides a transparent electrode, a photoconductive layer member, and a wavelength that allows light in the wavelength range of read light to be reflected while transmitting light in the wavelength range of erase light. In the light-to-light conversion element including a reflective mirror member having selectivity, an optical member that changes the state of light according to the intensity distribution of an applied electric field, and a transparent electrode, the wavelength of the read light described above. A configuration in which a plurality of minute reflecting mirrors are arranged in a state of being separated from each other as a reflecting mirror member having a wavelength selectivity capable of reflecting the light in the range and transmitting the light in the wavelength range of the erased light. The present invention provides a light-to-light conversion element using the same.

(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. 1 and 2 are side cross-sectional views showing different embodiments of the light-to-light conversion element of the present invention. In the light-to-light conversion element shown in each drawing, GP1 and GP2 are glass plates, and Et1. , Et2 are transparent electrodes, 1
1 is a terminal, PCL is a photoconductive layer member, PML is an optical member that changes the state of light according to the intensity distribution of an applied electric field (for example, lithium niobate single crystal having an electro-optical effect, or bismuth silicate, Alternatively, a material layer for light modulation such as a nematic liquid crystal layer may be used), Vb is a power source, SW is a changeover switch, WL is writing light, RL is reading light, and EL is erasing light.

In FIG. 1 and FIG. 2, DMLrd is a plurality of minute reflecting mirrors having a wavelength-selective characteristic that reflects light in the wavelength range of the read light RL and transmits light in the wavelength range of the erase light EL. The reflecting mirror member is configured by arranging Mdr, Mdr ... In a state of being separated from each other.

That is, in the light-to-light conversion element of the present invention, the reflecting mirror member DMLrd used as a constituent part of the element is
A large number of reflecting mirrors Mdr, Mdr ... Having a predetermined wavelength selection characteristic, which are not continuous planar structures, are arranged in an electrically insulated state with being separated from each other. FIG. 3 shows an example of the arrangement of the plurality of reflecting mirrors Mdr, Mdr ... As shown in FIG. 3, the individual minute mirrors constituting the reflecting mirror member DMLrd are shown. As the reflective mirrors Mdr, Mdr ..., Dielectric mirrors having wavelength selectivity may be used, each of which is composed of a dichroic filter including a multilayer film of a thin film of SiO2 and a thin film of TiO2.

The shapes of the individual minute reflecting mirrors Mdr, Mdr, etc. forming the reflecting mirror member DMLrd described above may be arbitrary, and the individual minute reflecting mirrors forming the reflecting mirror member DMLrd may have any shape. The sizes of the reflecting mirrors Mdr, Mdr ... And the pitch of the array are set so that an image with high resolution can be obtained.

Further, it is easy to configure the reflecting mirror member DMLrd by arranging the reflecting mirrors Mdr, Mdr ... Of individual minute dimensions by applying a well-known thin film pattern forming technique. Reflector Mdr,
A reflecting mirror member DM configured by arranging a plurality of reflecting mirrors Mdr, Mdr ... With a pitch of 4 m of Mdr.
In the light-light conversion element using Lrd as a constituent member, 2
A resolution of 50 lines / mm can be obtained.

Further, a plurality of minute reflecting mirrors are arranged in a state of being separated from each other, that is, a reflecting mirror member formed by an arrangement of reflecting mirrors Mdr, Mdr ... In DMLrd, the reflecting mirror member D
In MLrd, the reflecting mirror Mdr having the above-mentioned minute dimensions,
If the light-shielding material that has the optical characteristics of absorbing the reading light and transmitting the erasing light and having an extremely large electric resistance is used to shield the portions between Mdr ..., The reading light RL will be on the photoconductive layer member PCL side. Since it is possible to eliminate problems such as leaking to the image and causing image bleeding, it is a preferable embodiment.

LSL in FIG. 2 is a light-shielding layer for read-out light, and this light-shielding layer LSL is, as described above, a minute portion of the reflecting mirror member DMLrd constituted by the array of the reflecting mirrors Mdr, Mdr ... In order to prevent the reading light RL that has passed through the portions between the reflecting mirrors Mdr, Mdr ... Of various sizes from causing the image bleeding on the photoconductive layer member PCL side, the photoconductive layer member PCL and the reflecting mirror member The light-shielding layer LSL is provided at the boundary with the DMLrd, and this light-shielding layer LSL is capable of absorbing light in the wavelength range of the read light and having a wavelength-selective light-shielding member capable of transmitting light in the wavelength range of the erase light. Composed.

When optical information is written in the light-to-light conversion element shown in FIGS. 1 and 2, switching of a circuit including a power supply Vb connected to the light-to-light conversion element and a changeover switch SW is performed. The movable contact of the changeover switch SW is switched to the fixed contact WR side by the changeover control signal supplied to the control signal input terminal 11, and the voltage of the power supply Vb is applied between the transparent electrodes Et1 and Et2 to photoconductive With the electric field applied between both ends of the layer member PCL, the writing light WL is incident from the glass plate GP1 side of the light-to-light conversion element to write the optical information to the light-to-light conversion element. Of.

That is, as described above, when the writing light WL that has entered the light-to-light conversion element passes through the glass plate GP1 and the transparent electrode Et1 and reaches the photoconductive layer member PCL, the electrical resistance value of the photoconductive layer member PCL is changed to that. The photoconductive layer member PCL and the reflecting mirror member D are changed in order to change corresponding to the optical image due to the incident light that has arrived.
A charge image corresponding to the optical image by the incident light reaching the photoconductive layer member PCL is generated at the boundary surface with MLrd.

In order to reproduce the optical information written in the form of the charge image corresponding to the optical image by the incident light from the light-to-light conversion element as described above, the movable contact of the changeover switch SW is fixed to the fixed contact WR side. With the state switched to, the voltage of the power supply Vb is applied between the transparent electrodes Et1 and Et2,
This can be performed by projecting the reading light RL having a constant light intensity from a light source (not shown) from the glass plate 2 side.

That is, as described above, the photoconductive layer member PC is provided on the boundary surface between the photoconductive layer member PCL and the reflecting mirror member DMLrd in the light-to-light conversion element in which the optical information is written by the incident light.
Since the charge image corresponding to the optical image by the incident light reaching L is generated, the optical member PML {which is provided in series with the reflecting mirror member DMLrd on the photoconductive layer member PCL is applied. Optical member that changes the state of light according to the intensity distribution of the electric field (for example, a lithium niobate single crystal having an electro-optical effect, or a material layer for light modulation such as a layer of bismuth silica oxide or a nematic liquid crystal) May be used.) In the following description, it may be described as a light modulating material layer member PML made of a single crystal of lithium niobate}, and an electric field having an intensity distribution corresponding to an optical image by incident light is added. It is in a state of being.

Then, since the refractive index of the light modulation material layer member PML made of the above-mentioned lithium niobate single crystal changes according to the electric field due to the electro-optical effect, the electric field having the intensity distribution corresponding to the optical image by the incident light is applied. The refractive index of the light modulating material layer member PML made of the lithium niobate single crystal provided in series with the photoconductive layer member PCL together with the reflecting mirror member DMLrd is the same as that of the optical information of the incident light described above. It changes according to the charge image generated corresponding to the optical image due to the incident light reaching the photoconductive layer member PCL at the interface between the photoconductive layer member PCL and the reflecting mirror member DMLrd in the light-to-light conversion element by writing. It will be

Read light RL on the glass plate GP2 side with respect to the light-light conversion element
When is projected, the read light RL projected on the glass plate GP2 side is transparent electrode Et2 → light modulation material layer member PML made of lithium niobate single crystal → reflecting mirror member DMLrd →
It progresses like.

The read light RL is reflected by the reflecting mirror member DMLrd having wavelength selectivity that allows light in the wavelength range of the read light to pass through and also allows light in the wavelength range of the erase light to pass through, and is reflected to the glass plate GP2 side. Although returning as light, the refractive index of the light modulation material layer member PML made of the lithium niobate single crystal changes according to the electric field due to the electro-optic effect, so that the reflected light of the read light RL is optically modulated by the lithium niobate single crystal. Due to the electro-optical effect of the material layer member PML, image information corresponding to the intensity distribution of the electric field applied to the light modulation material layer member PML by the lithium niobate single crystal is included, and an optical image by the incident light is formed on the glass plate GP2 side. Generate a corresponding reconstructed optical image.

As described above, the read light RL projected from the glass plate GP2 side in the reproducing operation described above is emitted as the transparent electrode Et2 → the light modulation material layer member PML by the lithium niobate single crystal → the reflecting mirror member DMLrd →. Although traveling toward the conductive layer member PCL, the read-out light RL is transmitted to the reflecting mirror member DMLr before it reaches the photoconductive layer member PCL.
By being reflected by d, the light modulating material layer member PML made of lithium niobate single crystal follows an optical path such as the transparent electrode Et2 → the glass plate GP2.
There is no possibility that L reaches the photoconductive layer member PCL and adversely affects the charge image due to the incident light written.

As described above, in the light-light conversion element shown in FIGS. 1 and 2, the writing operation is performed by making the writing light WL incident from the glass plate GP1 side, and the reading light RL is made incident on the glass plate GP2 side. By doing so, the optical image is reproduced.

Next, when erasing the information written in the light-to-light conversion element shown in FIGS. 1 and 2, between the terminals of the light-to-light conversion element shown in FIGS. The movable contact of the changeover switch SW is switched to the fixed contact E side by the changeover control signal supplied to the input terminal 11 of the changeover control signal in the connected changeover switch SW, and the transparent electrodes Et1 and Et2 are connected to each other. After electrically short-circuiting the transparent electrodes Et1 and Et2 to the same potential to prevent an electric field from being applied between both ends of the photoconductive layer member PCL, the light-light conversion element shown in FIGS. This is performed by making the erasing light EL enter from the glass plate GP2 side.

In the light-light conversion element shown in FIGS. 1 and 2, the erasing light EL incident from the glass plate GP2 side is the glass plate GP2 →
Transparent electrode Et2 → light modulation material layer member PML made of lithium niobate single crystal → reflecting mirror member DMLrd → photoconductive layer member P
The photoconductive layer member PCL reaches the photoconductive layer member PCL by a route such as CL, and the erasing light EL reduces the electric resistance value of the photoconductive layer member PCL, and the photoconductive layer member PCL and the reflecting mirror member DMLrd.
The charge image formed on the boundary surface between and is erased.

As described above, in the light-light conversion element shown in FIGS. 1 and 2, while reflecting the light in the wavelength region of the read light RL,
A reflecting mirror member D formed by arranging a plurality of minute reflecting mirrors Mdr, Mdr ... Having a wavelength selective characteristic capable of transmitting light in the wavelength region of the erasing light EL.
Since the light-to-light conversion element of the present invention is provided with the MLrd, an image with high resolution can be obtained.

(Effects of the Invention) As is apparent from the above description, the light-to-light conversion element of the present invention includes a transparent electrode, a photoconductive layer member, and
A reflector member having wavelength selectivity that reflects light in the wavelength range of read light and transmits light in the wavelength range of erase light, and changes the light state according to the intensity distribution of the applied electric field. In a light-to-light conversion element formed by laminating an optical member and a transparent electrode, 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. Since it is a light-light conversion element using a configuration in which a plurality of minute reflecting mirrors are arranged in a state of being separated from each other as a reflecting mirror member having
In the light-to-light conversion element of the present invention, it is easy to satisfactorily read a high-definition signal by two-dimensional scanning.
According to the present invention, the above-mentioned problems of the conventional light-to-light conversion element can be solved well.

[Brief description of drawings]

1 and 2 are side sectional views showing different embodiments of the light-to-light converting element of the present invention, FIG. 3 is a plan view of a part of the reflecting mirror member, and FIG. 4 is a light-to-light converting element. FIG. 5 and FIG. 6 are side sectional views showing the configuration of a conventional example of the light-to-light conversion element, and FIG. It is a curve figure which shows the wavelength selection characteristic example of a body mirror. 1, 2, GP1, GP2 ... Glass plate, 3, 4, Et1, Et2 ... Transparent electrode, 5, 6, 11 ... Terminal, 7, PCL ... Photoconductive layer member, 9, PML ... Intensity distribution of applied electric field Optical member for changing the state of light in accordance with, 10, Vb ... Power source, SW
... Changeover switch, WL ... Write light, RL ... Read light, E
L ... Erase light, LSL ... Light shield layer for read light, DML
rd ... While reflecting the light in the wavelength range of the read light RL,
A reflecting mirror member constituted by arranging a plurality of minute reflecting mirrors Mdr having a wavelength selective characteristic capable of transmitting light in the wavelength range of the erasing light EL in a state of being separated from each other; ... dielectric mirror, 8R ... 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,

Front page continuation (72) Inventor Asakura Den 12, 3-12 Moriya-cho, Kanagawa-ku, Yokohama, Kanagawa Japan Victor Company of Japan (56) References JP-A-49-11149 (JP, A) JP-A-49- 77596 (JP, A) JP-A-48-23459 (JP, A) JP-B-44-9517 (JP, B1)

Claims (2)

[Claims] 1. A transparent electrode, a photoconductive layer member, and a reflecting mirror member having wavelength selectivity capable of reflecting light in the wavelength region of read light and transmitting light in the wavelength region of erase light.
In a light-to-light conversion element formed by laminating a transparent electrode and an optical member that changes the state of light according to the intensity distribution of an applied electric field, the light in the wavelength range of the above-mentioned reading light is reflected and erased. Light-light using a structure in which a plurality of minute reflecting mirrors are arranged in a state of being separated from each other as a reflecting mirror member having a wavelength selectivity capable of transmitting light in the wavelength range of light Conversion element 2. The light in the wavelength range of the reading light is provided at least in a portion of the reflecting mirror member having a structure in which a plurality of minute reflecting mirrors are arranged in a state of being separated from each other, at a portion without the minute reflecting mirrors. The light-to-light conversion element according to claim 1, further comprising a light shielding means.