JPH02177676A - Image pickup device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of shading in a reproduced picture by outputting only a signal corresponding to optical information read out during one partial period in a period except a period in which an operation for erasing a charge pattern is executed. CONSTITUTION:Under a state in which the voltage of a power source 10 is applied through a changeover switch SW to the interval between transparent electrodes 3 and 4 in a photo-photo conversion element PPC under a state in which the optical information is written from the side of a glass plate 1, and the charge pattern corresponding to an optical image by a writing light beam is formed on the boundary surface between a photoconductive layer 7 and a dielectric mirror 8 of the photo-photo conversion element PPC, a reading out light beam RL of coherent light is radiated from a light source PSr of the reading out light beam composed as a laser beam flying-spot scanner. Here, a period mentioned as 'reading out' as a period to radiate the reading out light beam RL is set widely shorter compared with another period mentioned as '1 frame'. Thus, it can be prevented that large shading occurs in a time sequential electric signal to be generated correspondingly to the reading out period.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an imaging device, and particularly to an imaging device with high resolution.

(Prior Art) A video signal obtained by capturing an optical image of a subject with an imaging device is easy to edit, trim, and perform other image signal processing, and a recording member with reversibility that can erase low recorded signals is used. However, imaging devices that have been commonly used to generate video signals have the characteristic that they can be easily used for recording and reproducing. The formed optical image of the subject is converted into electrical image information corresponding to the optical image of the subject by the photoelectric conversion section of the image sensor, and the electrical image information is converted into a serial video signal on the time axis. It is well known that various image pickup tubes and various solid-state image pickup devices have been conventionally used as the above-mentioned image pickup elements in the configuration of image pickup apparatuses.

As is well known, in recent years, as the demand for high-quality and high-resolution playback images has increased, new television systems such as so-called EDTV and HDTV have been proposed. It is.

By the way, in order to obtain high-quality, high-resolution reproduced images, an imaging device that can reproduce high-quality, high-resolution reproduced images and generate clear video signals is required. In an imaging device that uses an image pickup tube as an image pickup element, there is a limit to miniaturization of the electron beam diameter in the image pickup tube, so high resolution cannot be expected by miniaturization of the electron beam diameter, and Since the target capacity of the tube increases in proportion to the target area, it is impossible to achieve higher resolution by increasing the target area. As the frequency band of the video signal increases from several tens of MHz to several hundred MHz or more, the S/N ratio increases.
For these reasons, it is difficult to generate a video signal that allows an imaging device to reproduce a high-quality, high-resolution reproduced image.

The above point will be specifically explained as follows. In other words, in order to generate a video signal that can reproduce high-quality, high-resolution images using an image pickup device that uses an image pickup tube as an image sensor, it is necessary to miniaturize the electron beam diameter in the image pickup tube and to However, there is a limit to miniaturizing the electron beam diameter of the image pickup tube due to the performance of the electron gun in the image pickup tube and the feeding of the focusing system. There is a limit to increasing resolution by making the diameter smaller, and if you use an imaging lens with a large image size and try to obtain high resolution by increasing the target area, the target area will increase. Due to the increase in the target capacity of the image pickup tube, the high-frequency signal component of the image pickup tube output signal decreases, and the S/N of the image pickup tube output signal decreases significantly. It is not possible to properly generate a video signal that can reproduce a high-quality, high-resolution reproduced image.

In addition, in order to reproduce high-quality, high-resolution images using an imaging device that uses a solid-state image sensor as an image sensor, it is necessary to use a solid-state image sensor with a large number of pixels; As more and more solid-state image sensors are driven, the clock frequency for driving them becomes higher (for example, in the case of a video camera, the clock frequency for driving the solid-state image sensor is several hundred MHz), and the frequency of the clock used to drive the solid-state image sensor becomes higher. Since the capacitance value of the circuits used in solid-state imaging devices has increased due to the increase in the number of pixels, such solid-state imaging devices are not practical given the current situation where the clock frequency limit for solid-state imaging devices is said to be 20 MHz. It is considered that it cannot be constituted as a thing.

As described above, the conventional image pickup apparatus has been unable to reproduce a high-quality, high-resolution reproduced image and generate a clear video signal satisfactorily due to the presence of an image pickup element that is essential to its configuration.

Therefore, the applicant company has developed an imaging device capable of solving the above-mentioned problems by first providing at least a photoconductive layer member, a VT heavy mirror, and a light modulating material layer member between two transparent electrodes. An optical image of the subject is formed by an imaging lens on the constructed light-light conversion element, and the above-mentioned light-
We have proposed an imaging device that can generate a high-resolution video signal by reading out an optical image of an object and corresponding optical image information using light from a photoconversion element and photoelectrically converting it.

FIG. 2 is a side sectional view showing an example of the configuration of the light-to-light conversion element rpc, and the light-to-light conversion element PP shown in FIG.
In C, 1 and 2 are glass plates, 3 and 4 are transparent electrodes, and 5.
6 is a terminal, 7 is a photoconductive layer, 8 is a dielectric mirror, and 9 is an optical member (for example, a light modulating material layer such as a lithium niobate single crystal) that changes the state of light according to the intensity distribution of the applied electric field. , or nematic liquid crystal layer), WL is the writing light,
RL is a reading light, and EL is an erasing light.

In FIG. 2, the direction of incidence of the erasing light EL is the readout light R.
Although it is shown as being the same as the incident direction of light L, this is due to the light transmittance characteristic such that the dielectric mirror 8 in the light-to-light conversion element PPC reflects the readout light RL and transmits the erasing light EL. 3 shows the direction of incidence of erasing light on the light-to-light conversion element in the case where a light-to-light conversion element is used.

Now, when writing optical information to the light-to-light conversion element PPC shown in FIG. 2, the example shown in FIG. 1 and FIG. A circuit consisting of fftilJi (10) and a changeover switch SW is connected as shown in FIG.
With the movable contact of the changeover switch SW switched to the fixed contact WR side, a voltage of g10 is applied between the transparent electrodes 3 and 4, so that an electric field is applied between both ends of the photoconductive layer 7, By making the writing light WL enter the light-to-light conversion element PPC from the glass plate 1 side, optical information is written to the light-to-light conversion element PPC.

That is, when the writing light WL incident on the light-to-light conversion element PPC as described above passes through the glass plate 1, the transparent 1, and the pole 3 and reaches the photoconductive layer 7, the electrical resistance value of the photoconductive layer 7 increases. Since the change corresponds to the optical image caused by the incident light that has reached the photoconductive layer 7, a charge image that corresponds to the optical image caused by the incident light that has reached the photoconductive layer 7 is formed at the interface between the photoconductive layer 7 and the dielectric mirror 8. arise.

In order to reproduce optical information written in the form of an optical image by incident light and a corresponding charge image from the light-to-light conversion element as described above, the movable contact of the changeover switch SW is moved to the fixed contact WR side. In the state where the voltage is switched to , the voltage g10 is applied between the transparent electrodes 3 and 4 via the terminals 5 and 6, and the voltage shown in the figure is shown from the glass plate 2 side of the light-to-light conversion element PPC. This can be done by projecting readout light RL of constant light intensity from a light source.

In other words, the interface between the photoconductive layer 7 and the dielectric mirror 8 in the light-to-light conversion element in which optical information has been written by the incident light as described above has the optical information generated by the incident light that has reached the photoconductive layer 7. A charge image corresponding to the image is generated, and an optical member 9 (for example, a lithium niobate single crystal 9), which is provided in series with the photoconductive layer 7 together with a dielectric mirror 8, An electric field with an intensity distribution corresponding to the optical image created by light is applied.

Since the refractive index of the lithium niobate single crystal 9 changes depending on the electric field due to the electro-optic effect, the photoconductive layer 7 is applied with an electric field having an intensity distribution corresponding to the optical image formed by the incident light. The refractive index of the lithium niobate crystal 9, which is provided in series with the dielectric mirror 8, is the same as that of the light guide ffi layer 7 in the light-to-light conversion element PPC by writing optical information using the incident light as described above.
This changes in accordance with the charge image generated at the interface between the light guide 11 layer 7 and the dielectric mirror 8 corresponding to the optical image caused by the incident light that reaches the light guide layer 7 .

Therefore, when the readout light RL is projected onto the glass plate 2 side, the readout light RL projected onto the glass plate 2 side as described above changes from the transparent electrode 4 to the lithium niobate single crystal 9 to the dielectric mirror 8. → The above-mentioned readout light RL is then reflected by the vI dielectric mirror and returns to the glass plate 2 side as reflected light, but the refractive index of the lithium niobate crystal 9 is due to the electro-optic effect. Therefore, the reflected light of the readout light RL contains image information according to the intensity distribution of the electric field applied to the lithium niobate crystal 9 due to the electro-optical effect of the lithium niobate crystal 9. As a result, a reproduced optical image corresponding to the optical image created by the incident light is generated on the glass plate 2 side.

Further, in order to erase the information written by the write light WL as described above, a switching control signal is supplied to the input terminal 11 of the switching control signal in the switching switch SW, and the movable contact of the switching switch SW is is switched to the fixed contact E side, and the potentials of terminals 5 and 6 in the light-to-light conversion element PPC are made the same so that no electric field is generated between the transparent electrodes 3 and 4, and then a --like intensity distribution is detected from the glass plate 2 side. Erasing light EL
This is done by injecting

As described above, in an imaging device configured using a light-to-light conversion element PPC configured to include at least a photoconductive layer member, a dielectric mirror, and a light modulating material layer member between two transparent electrodes, the light- An optical image of the object is applied to the photoconversion element PPC to form a high-resolution charge image corresponding to the optical image, and the charge image corresponding to the optical image of the object is read out as optical image information using light. A high resolution video signal can be generated by photoelectric conversion.

(Problems to be Solved by the Invention) Incidentally, in an imaging device configured using the above-mentioned light-to-light conversion element PPC, the photoconductive layer 7 laminated between the two transparent electrodes 3 and 4, the dielectric Body mirror8. The light-to-light conversion element PPC is composed of constituent members such as an optical member (for example, a light modulating material layer such as a lithium niobate single crystal) 9 that changes the state of light according to the intensity distribution of an applied electric field. Since each component has a capacitance, the photoconductive layer 7 in the light-to-light conversion element PPC is
The amount of charge of the charge image generated at the boundary between and the dielectric mirror 8 is:
Due to the time constant of the light-to-light conversion element PPC, the write light increases as the irradiation time of the write light becomes longer and finally reaches saturation.

Furthermore, when forming a charge image corresponding to a new optical image in the light-to-light conversion element PPC, the previous charge image is erased, but the charge image in the light-to-light conversion element rpc is When generating a time-series electrical signal based on the erasing operation, the electrical signals of different parts on the time axis in the time-series electrical signal generated based on the charge image from the time when the erasing operation was performed. The level changes gradually depending on the length of time from the time of erasure to the time of generation, causing shading in the reproduced image due to the signal.

(Means for Solving the Problems) The present invention provides photoconductivity in a light-to-light conversion element configured to include at least a photoconductive layer member, a dielectric mirror, and a light modulating material layer member between two transparent electrodes. means for causing light from a subject to enter the layer member side to generate a charge image corresponding to an optical image of the subject on a light-to-light conversion element; and light-to-light conversion from the light modulating material layer member side of the light-to-light conversion element. The device includes means for reading out a charge image corresponding to the optical image of the object as optical information by means of readout light incident on the element, and means for erasing the charge image corresponding to the optical image of the object. In an imaging device that performs an image erasing operation and a charge image readout operation intermittently, the optical information read out during a part of the period excluding the period in which the charge image erasing operation is performed. an imaging device comprising means for ensuring that only corresponding signals are output, and at least a light guide I! between two transparent electrodes; Light from a subject is incident on the photoconductive layer member side of a light-to-light conversion element configured with a layer member, a dielectric mirror, and a light modulating layer member, and an optical image of the subject is formed in the light-to-light conversion element. A means for generating a corresponding charge image and a readout light incident on the light-to-light conversion element from the light modulating material layer member side of the light-to-light conversion element convert the charge image corresponding to the optical image of the subject into optical information. and means for erasing a charge image corresponding to the optical image of a subject, and is configured to intermittently repeat the operation of erasing the charge image and the operation of reading the charge image. means for causing light from a subject to enter the light-to-light conversion element through an optical shutter; and light read out during a period when the light incident on the light-to-light conversion element is blocked by the optical shutter. An object of the present invention is to provide an imaging device including means for outputting only a signal corresponding to information.

(Example) Hereinafter, specific contents of the imaging device of the present invention will be described in detail with reference to the accompanying drawings. 1 and 4 are block diagrams showing schematic configurations of different embodiments of the imaging device of the present invention, FIG. 2 is a block diagram showing an example configuration of a light-to-light conversion element, and FIG. 1 is a waveform diagram for explaining the operation of the imaging device of the present invention shown in FIG. 5, FIG. 5 is a plan view showing an example configuration of an optical shutter, and FIG. FIG.

1 and 4 are block diagrams of an imaging device configured using a light-to-light conversion element PPC having the configuration already described with reference to FIG. 2, for example. 4
In the light-light conversion element PPC shown in the figure,
A drawing code 1 is attached to the front side of the glass plate 1 on which the writing light WL, which is shown by the drawing code WL in the figure, is incident, and the reading light RL and the drawing code EL, which are shown by the drawing code RL in the figure, are attached to the front side of the glass plate 1. The drawing code 2 is attached to the front side of the glass plate 2 on which the erasing light EL shown in is incident, to clarify the correspondence with the light-to-light conversion element PPC shown in FIG. However, in FIGS. 1 and 4, specific illustrations of other constituent parts of the light-to-light conversion element PPC are omitted for the sake of simplification of illustration.

In FIGS. 1 and 4, O is the object, L is the photographic lens, BSI, BS2 is the beam splitter, and PSr is the light source of the readout light RL (the light source of the readout light PSr is, for example, a flying spot scanner using a laser beam). In the following description, it is assumed that a flying spot scanner using a laser beam is used as the light source PSr of the readout light), PSs is the light source of the erasing light EL, and PLP is the polarized light source. board, PD is a photodetector, 5, 6.11 are terminals, 10 is a power source, SW is a changeover switch, and in FIG. 4, S is an optical shutter, and this optical shutter S is, for example, the fifth The structure illustrated in the figure can be used.

In the optical shutter S shown in FIG.
13 is a light-transmitting window, and 14 is a light-shielding part. When the rotation shaft 12 of the optical shutter S is driven and rotated by a drive motor (not shown), the optical shutter S is connected to the light-transmitting window 13 and light-shielding part. The part 14 receives light from the imaging lens L.
The writing light incident on the glass plate 1 side of the light conversion element PPC is allowed to pass through the transparent window 13 and is blocked by the light shielding section 14 .

First, in the imaging apparatus of the present invention shown in FIG. The first in the light-to-light conversion element PPC when it is in the operation mode and readout operation mode.
．． The second transparent electrodes 3 and 4 have a movable contact and a fixed contact WR.
Since the voltage of the power supply 10 is applied through the changeover switch SW which is switched to the side, light corresponding to the optical image of the subject O is applied to the glass plate 1 side through the photographing lens L. In the light conversion element PPC, as already described with reference to FIG.
It passes through the optical path of → transparent electrode 3 → photoconductive layer 7 → and reaches photoconductive layer 7.

At the interface between the photoconductive layer 7 and the dielectric mirror 8 in the light-to-light conversion element PPC, a charge image corresponding to the optical image created by the incident light that has reached the photoconductive layer 7 is generated.

As described above, optical information is written from the glass plate 1 side, and a charge image corresponding to the optical image created by the writing light is created on the interface between the photoconductive layer 7 and the dielectric mirror 8 of the light-to-light conversion element PPC. In the state where the voltage of the power supply 10 is applied via the changeover switch SW between the transparent electrodes 3 and 4 in the light-to-light conversion element PPC where the The readout light RL of the coherent light is emitted from the readout light source PSr, and the period for emitting the readout light RL described above is shown in FIG.
The period indicated as "1 frame" is much shorter than the period indicated as "1 frame" in (a) of Fig. 3, and is generated in correspondence with the reading period. This prevents large shading from occurring in the time-series electrical signals.

The laser beam flying spot scanner described above has a configuration in which the laser beam emitted from the laser light source is deflected in two orthogonal directions by an optical deflector and then emitted as a beam parallel to the optical axis by a lens system. Things can be used.

The laser beam emitted from the laser beam flying spot scanner described above passes through the beam splitter BSI, is reflected by the beam splitter B32, and is projected onto the glass plate 2 side of the light-to-light conversion element PPC. As already described with reference to FIG. 2, the readout light RL projected onto the glass plate 2 travels as follows: transparent electrode 4 → lithium niobate single crystal 9 → dielectric mirror 8 → 1 Next, the readout light RL is reflected by the dielectric mirror 8, which has wavelength selectivity such that it reflects light in the wavelength range of the readout light and transmits light in the wavelength range of the erasing light, and passes through the glass plate 2. It returns to the side as reflected light, but the lithium niobate single crystal 9
Since the refractive index of changes depending on the electric field due to the electro-optic effect, the reflected light of the readout light RL is an image that corresponds to the intensity distribution of the electric field applied to the lithium niobate single crystal 9 due to the electro-optic effect of the lithium niobate single crystal 9. It contains information, and produces a reproduced optical image on the glass plate 2 side based on optical information corresponding to the optical image based on the incident light.

When a flying spot scanner using a laser beam is used as the light source PSr of the readout light RL, the light-light conversion element P
Since the reproduced optical image appearing on the glass plate 2 side of the PC is constructed by flying point scanning, the light of the reproduced optical image is transmitted to the beam splitter BS2 and the polarizing plate P.
LP and is applied to the photodetector PD as light whose amount changes in accordance with the optical information of the reproduced optical image described above, so that the photodetector PD outputs light corresponding to the optical image of the subject O The video signal that is present will be output.

In the imaging device shown in Figure 1, it is necessary to write and read out images of different subjects for each predetermined length of one frame on the time axis to generate a video signal. In order to write and read images of different subjects for each frame of time predetermined by the time axis E, the above-mentioned method is required as shown in FIG. 3(a). Before a new optical image of the subject is written every predetermined length of one frame on the time axis, it is necessary to erase the electric charge image corresponding to the previously written optical image. It is said that

And, the above-mentioned erasing operation in the imaging device is as follows.

Before a new optical image of the object is written every predetermined time length of one frame on the time axis, (
This is carried out during a predetermined time indicated as "erasing" in a), and the period of "erasing" mentioned above is the vertical blanking period of the video signal output from the photodetector PD. As described above with reference to FIG. 3, the terminals 5 and 6 of the light-to-light conversion element are connected in correspondence with the vertical blanking period in the video signal output from the photodetector PD. The movable contact of the changeover switch SW is switched to the fixed contact E side by the changeover control signal supplied to the changeover control signal input terminal 11 of the changeover switch SW connected between the transparent IT poles 3, 4 are electrically short-circuited to make the transparent electrodes 3 and 4 have the same potential, and the photoconductive layer 7
At the same time, the erasing light EL is emitted from the erasing light source PSe, and the erasing light EL is transmitted to the glass plate 2 side of the light-to-light conversion element PPC via the beam splitters BSI and BS2. This is done so that the light is incident from the source.

The erasing light EL incident on the glass plate 2 side of the light-to-light conversion element as described above is transmitted through the glass plate 2 → transparent ffi electrode 4 → lithium niobate single crystal 9 → dielectric mirror as already described with reference to FIG. 8→The photoconductive layer 7 reaches the photoconductive layer 7 through a path such as the photoconductive layer 7, and the erasing light EL lowers the electrical resistance value of the photoconductive layer 7, and the interface between the photoconductive layer 7 and the dielectric mirror 8. Erases the charge image that was formed on the

During the period indicated as "accumulation" in FIG. 3(a), the writing light incident on the light-to-light conversion element PPC
Photoconductive layer 7 and v1111 in light-photo conversion element PPC
This is a period in which a charge image is formed on the interface with the body mirror 8, but is shown in FIG. 3(a) as a period other than the "erasing" period shown in FIG. 3(a). The period shown as 98tno, ie.

By the writing light incident on the light-light conversion element PPC,
In the normal video imaging mode in which the readout operation is performed throughout the period during which a charge image is accumulated on the interface between the photoconductive layer 7 and the dielectric mirror 8 in the light-to-photo conversion element PPC, for the reasons mentioned above, Although shading occurs in the reproduced image, as in the period indicated as "readout" in FIG. 3(b), there is no shading in FIG.
Since the change in the amount of accumulated charge during the readout period, which is much shorter than the period described as "1 frame", is small, the time-series electric signal generated corresponding to the readout period described above is It is clear that no significant shading occurs in the middle. In addition, the period indicated as T in FIG. 3(b) indicates the period excluding the readout period in one frame period, and this period T is divided from the erasure period and the accumulation period. Become. It goes without saying that the vI product of charges is also performed during the readout period in FIG. 3(b). .

As is clear from the foregoing, in the imaging apparatus of the present invention shown in FIG. Therefore, no shading occurs in the reproduced image obtained by the video signal.

Next, in the imaging device of the present invention shown in FIG.
When the optical shutter S is open, an optical image of the subject 0 is transmitted to the light-to-light conversion element PPC as writing light WL to the glass plate via the imaging lens L and the transparent window 13 of the optical shutter S. When the optical shutter S is closed, the optical image of the subject 0 is blocked by the light shielding part 14 in the optical shutter S, so that it is not written into the light-to-light conversion element PPC. Light WL is not provided.

The opening/closing state of the optical shutter S described above is shown in (b) in FIG.
) is shown. FIG. 6(a) shows the erasing period and the accumulation period in one frame period, as in FIG. 3(a) described above.

The first . The second transparent electrodes 3 and 4 have a changeover switch SW in which the movable contact is switched to the fixed contact WR side.
Since a voltage of 10 is applied to the electric current i1 via the photoconductor i1, the light corresponding to the optical image of the subject 0 passes through the imaging lens L and the transparent window 13 of the optical shutter S to the light-to-light conversion element PPc.
On the other hand, in the light-light conversion element PPC in a state where the writing light WL is incident from the glass plate 1 side.

As already mentioned with reference to FIG. 2, during the writing operation, the writing light that enters the light-to-light conversion element PPC from the glass plate 1 side passes through the optical path of the glass plate 1 → transparent electrode 3 → photoconductive pIJ 7 → The light then reaches the photoconductive layer 7, and a charge image corresponding to the optical image caused by the incident light that has reached the photoconductive layer 7 is generated at the interface between the photoconductive layer 7 and the dielectric mirror 8 in the light-to-light conversion element PPC.

Furthermore, when the optical shutter S is closed, the optical image of the subject O is blocked by the light blocking portion 14 of the optical shutter S.

No writing light WL is given to the light-light conversion element PPC,
In the light-to-light conversion element PPC when the optical shutter S is closed, no charge is accumulated by the writing light WL.In the imaging device shown in FIG. 4, the optical shutter S is closed as described above and the light- Write light W with optical conversion element PPC
A readout operation is performed by the readout light RL when no charge is accumulated by the L.

That is, as described above, optical information is written from the side of the glass plate 1, and an optical image corresponding to the writing light is created on the interface between the photoconductive layer 7 and the dielectric mirror 8 of the light-to-light conversion element PPc. Light-light conversion element PPC in a state where a charge image is generated
When the voltage of the power supply 10 is applied between the transparent electrodes 3 and 4 via the changeover switch SW, and the optical shutter S is closed, charge is accumulated by the writing light WL in the light-to-light conversion element PPC. When the reading light RL is not performed, the readout light RL of coherent light is emitted from the readout light source PSr configured as a laser beam flying spot scanner, but the period of emitting the readout light RL is as follows: Figure 6 (b)
This readout period is shown in (a) of Figure 6, which is the same period as the period labeled "1 frame" in (,) of Figure 3. This period is considered to be shorter than the current period.

During the reading period, the optical shutter S is closed and the light-to-light conversion element PPC is in a state where no charge is accumulated by the writing light WL. In the time-series electric signal generated in correspondence with the optical image generated by the incident light that has reached the leading conductive layer 7 at the interface between the photoconductive layer 7 and the dielectric mirror 8, the electric charge image is generated correspondingly. , no shading occurs at all.

The laser beam flying spot scanner described above has a configuration in which the laser beam emitted from the laser light source is deflected in two orthogonal directions by an optical deflector and then emitted as a beam parallel to the optical axis by a lens system. Things can be used.

The laser beam emitted from the laser beam flying spot scanner described above passes through the beam splitter BSI, is reflected by the beam splitter BS2, and is projected onto the glass plate 2 side of the light-to-light conversion element PPC. As already described with reference to FIG. 2, the readout light RL projected onto the glass plate 2 travels as follows: transparent electrode 4 → lithium niobate single crystal 9 → dielectric mirror 8 → 1 Next, the above-mentioned readout light RL reflects light in the wavelength range of the readout light.

The glass plate 2 is reflected by the dielectric mirror 8 which transmits light in the wavelength range of the erasing light and has wavelength selectivity like that of the erase light.
However, since the refractive index of the lithium niobate single crystal 9 changes depending on the electric field due to the electro-optic effect, the reflected light of the readout light RL is reflected due to the electro-optic effect of the lithium niobate single crystal 9. Lithium niobate single crystal 9
It contains image information corresponding to the intensity distribution of the electric field applied to the glass plate 2, and produces a reproduced optical image on the glass plate 2 side based on optical information corresponding to the optical image formed by the incident light.

When a flying spot scanner using a laser beam is used as the readout light RL @PSr, the light-light conversion element P
Since the reproduced optical image appearing on the glass plate 2 side of the PC is constructed by flying point scanning, the light of the reproduced optical image is transmitted to the beam splitter BS2 and the polarizing plate PL.
P and is applied to the photodetector PD as light whose amount changes in accordance with the optical information of the reproduced optical image described above. The video signal that is present will be output.

In the imaging device shown in FIG. 4, it is necessary to write and read out images of different subjects for each predetermined length of one frame on the time axis to generate a video signal. In order to read out images of different subjects for each predetermined length of one frame on the time axis, as shown in FIG. Before a new optical image of the object is written every predetermined length of one frame on the time axis, it is necessary to erase the electric charge image corresponding to the previously written optical image. be done.

And, the above-mentioned erasing operation in the imaging device is as follows.

Before a new optical image of the object is written every predetermined time length of one frame on the time axis, (
This is carried out during a predetermined time indicated as "erasing" in a), and the period of "erasing" mentioned above is the vertical blanking period of the video signal output from the photodetector PD. As described above with reference to FIG. 2, the terminals 5 and 6 of the light-to-light conversion element are connected in correspondence with the vertical blanking period in the video signal output from the photodetector PD. The movable contact of the changeover switch SW is switched to the fixed contact E side by a changeover control signal supplied to the input terminal 11 of the changeover control signal in the changeover switch SW connected between the transparent electrodes 3 and 4. The gap between the transparent electrodes 3 and 4 is electrically shortened to have the same potential, so that no electric field is applied between both ends of the photoconductive layer 7, and the erasing light EL is emitted from the erasing light gPSe. Erasing light E
The light beam L is made to enter from the glass plate 2 side of the light-to-light conversion element PPC via the beam splitters BSI and BS2.

As described above, the erasing light EL incident on the glass plate 2 side of the light-to-light conversion element is transmitted through the glass plate 2→transparent electrode 4→lithium niobate 11 single crystal 9→! 1i
Light guide ft through a path such as ffi body mirror 8 → photoconductive layer 7
Upon reaching the layer 7, the erasing light EL lowers the electrical resistance value of the photoconductive layer 7 and erases the charge image formed at the interface between the photoconductive layer M7 and the dielectric mirror 8.

During the period indicated as "accumulation" in FIG. 6(b), the writing light incident on the light-to-light conversion element PPC during the period when the optical shutter S is open causes the light to become light-to-light. This is a period during which a charge image is formed on the interface between the photoconductive layer 7 and the dielectric mirror 8 in the conversion element PPC. Note that even if the writing light is incident on the light-to-light conversion element PPC during the period in FIG. 6(b) that corresponds to the "erase" period shown in FIG. 6(a), No charge is accumulated by the writing light.

In the imaging device shown in FIG. 4, the period other than the period indicated as "erasure" in FIG.
By the writing light incident on the light-light conversion element PPC,
In a normal moving picture imaging mode, a readout operation is performed over the entire period during which a charge image is VSM-formed to the interface between the photoconductive layer 7 and the X-electrode mirror 8 in the light-to-photo conversion element PPC.

Although shading occurs in the reproduced image for the reasons mentioned above, the readout occurs during the period when the optical shutter S is closed, as in the period indicated as "readout" in FIG. 6(b). When an operation is performed, there is no change in the amount of charge accumulated during that period, so it is clear that no shading occurs in the time-series electrical signal generated in response to the readout period described above. be.

As is clear from the foregoing, in the imaging device of the present invention shown in FIG. 4, the optical shutter S is closed during periods other than the erasing period in one frame period, and the accumulation of charges during this period is Since the read operation is performed during a period in which there is no change in the amount, no shading occurs in the generated time-series electrical signal.

(Effects of the Invention) The present invention provides a light-to-light conversion element that includes at least a photoconductive layer member, a dielectric mirror, and a light modulating material layer member between two transparent electrodes. means for causing light to enter the light-to-light conversion element to generate a charge image corresponding to an optical image of a subject; The device includes a means for reading out a charge image corresponding to the optical image of the subject as optical information by using readout light, and a means for erasing the charge image corresponding to the optical image of the subject, and erases the charge image. In an imaging device configured to intermittently repeat charge image readout operations, only signals corresponding to optical information read out during a part of the period excluding the period in which charge image erasing operations are performed are output. and a light-light conversion element configured to include at least a photoconductive layer member, a dielectric mirror, and a light modulating material layer member between two transparent electrodes. A means for causing light from a subject to enter the conductive layer member side to generate a charge image corresponding to an optical image of the subject on a light-to-light conversion element; means for reading out, as optical information, a charge image corresponding to the optical image of the subject using readout light incident on the conversion element;

In an imaging apparatus that is equipped with the optical image of the object described above and a means for erasing the corresponding charge image, and is configured to intermittently repeat the operation of erasing the charge image and the operation of reading out the charge image, the light from the subject is means for causing the light to enter the light-to-light conversion element through an optical shutter, and only a signal corresponding to optical information read during a period in which the light incident on the light-to-light conversion element is blocked by the optical shutter. Since the image capturing apparatus according to the present invention is equipped with a means for outputting Since a video signal is generated, shading does not occur in the reproduced image obtained by the video signal.

The optical shutter S is closed during the period excluding the erase period in one frame period, and the read operation is performed during the period when there is no change in the amount of accumulated charge during that period. Since shading does not occur in the time-series electrical signals, the present invention satisfactorily solves the above-mentioned conventional drawbacks.

[Brief explanation of the drawing]

1 and 4 are block diagrams showing the schematic configuration of different embodiments of the imaging device of the present invention, and FIG.
A block diagram showing an example configuration of a light conversion element, FIG.
A waveform diagram for explaining the operation of the illustrated imaging device of the present invention, FIG. 5 is a plan view showing an example configuration of an optical shutter, and FIG. 6 is a waveform diagram for explaining the operation of the imaging device of the present invention illustrated in FIG. It is. PPC...Light-light conversion element, WL...Writing light, R
L...Reading light, EL...Erasing light, 0...Subject, L...Photographing lens, BSI, BS2...Beam.
splitter. PSr...Light source of readout light RL, PSa...Light source of erasing light EL, PLP...Polarizing plate, PD...Photodetector, 1°2...Glass plate, 3,4... transparent electrode, 5,
6.11... Terminal, 7... Photoconductive layer, 8... Dielectric mirror, 9... Optical member that changes the state of light according to the intensity distribution of the applied electric field (for example, niobic acid light modulating material layer such as lithium r11 crystal or nematic liquid crystal layer), 10...power supply, SW...changeover switch,
S... Optical shutter, 12... Rotation axis, 13...
・Transparent window, 14...shading part, Procedural amendment (voluntary) Date of March 1989, Commissioner of the Japan Patent Office Yoshi 1) Moon Takeshi 1. - 1. Indication of the case Patent Application No. 43866 of 1988 2. Name of the invention Imaging device 3. Person making the amendment Relationship to the case Patent Applicant Address 3-12 Moriya-cho, Kanayō-ku, Yokohama-shi, Kanagawa Prefecture Name (432) Victor Company of Japan Co., Ltd. 4, Agent address: Tokyo Parts Co., Ltd. 3-4-19-915 Facsimile: 03 (472) 2257-5, Date of amendment order (voluntary) (3) Attached drawings (Figures 1, 2, and 4) 7. Contents of amendment (1) The scope of claims will be amended as shown in the attached sheet. (2) On page 13 of the specification, line 16, "comprising an electric layer member, a dielectric mirror, and a light modulating material layer member" is corrected as follows. "Includes an electrically conductive layer member and a light modulating material layer member" (3) In page 14, line 11, F of the specification, "at least a photoconductive layer member, a dielectric mirror, and luminous intensity" is corrected as follows. "At least the photoconductive layer member and the luminous intensity." (4) "Omitted" on page 16, line 13 of the specification is corrected as follows. (In the description of the embodiment described with reference to FIGS. 1 and 4, the light-to-light conversion element PPC used in the imaging device converts writing light and erasing light The light-to-light conversion element to be used in carrying out the present invention was supposed to be equipped with a dielectric mirror having a wavelength selective characteristic that transmits the light and reflects the readout light. Of course, in the case of a PPC that emits light for i!l! output light, a light-to-light conversion element PPC having a configuration that does not include a dielectric mirror may be used. ),” (5) “Kneading does not occur” on page 33, line 11 of the specification is amended as follows. [Kneading does not occur.] Note that the imaging device of the present invention is capable of capturing electromagnetic radiation in a broad sense, that is, part or all of the entire spectral range of radiation called electromagnetic waves (including the range from γ-rays, X-rays, etc. to long waves of radio waves). Needless to say, it is possible to write and read data using the 33rd page of the specification, line 14 [comprising an electric layer member, a dielectric mirror, and a light modulating material layer member] as follows. Correct to. "The photoconductive layer member and the light modulating material layer member are mJ (7) Specification, page 14, line 9 [at least the photoconductive layer member, the dielectric mirror, and the luminous intensity]" is corrected as follows. "At least the photoconductive layer member and the luminous intensity" (8) The attached drawings Figures 1, 2, and 4 are corrected as shown in the attached sheet. 1te, sheep "11': range rl, a subject on the photoconductive layer member side in a light-to-light conversion element configured to include at least a photoconductive layer member side Kerr modulating material layer member between two transparent electrodes. means for causing light to enter the light-to-light conversion element to generate a charge image corresponding to an optical image of a subject; The device includes a means for reading out a charge image corresponding to the optical image of the subject as optical information using readout light, and a means for erasing the charge image corresponding to the optical image of the subject, and erases the charge image. The imaging bag fi) is adapted to intermittently repeat the readout operation of the charge image, and corresponds to the optical information read out during a part of the period excluding the period in which the erase operation for the charge image is performed. 2. An imaging device comprising means for outputting only signals; at least a photoconductive layer member between two transparent electrodes;
Light from a subject is incident on the photoconductive layer member side of a light-to-light conversion element configured with a light-modulating material layer member, and a charge image corresponding to an optical image of the subject is generated in the light-to-light conversion element. and means for reading out a charge image corresponding to the optical image of the subject as optical information using readout light incident on the light-to-light conversion element from the light modulating material layer member side of the light-to-light conversion element; In an imaging apparatus that is equipped with the optical image of the object described above and a means for erasing the corresponding charge image, and is configured to intermittently repeat the operation of erasing the charge image and the operation of reading out the charge image, the light from the subject is means for causing the light to enter the light-to-light conversion element through an optical shutter, and only a signal corresponding to optical information read during a period in which the light incident on the light-to-light conversion element is blocked by the optical shutter. "An imaging device comprising a means for outputting" Procedural Amendment September 14, 1989 Director General of the Japan Patent Office Yoshi 1) Moon Yi 1, Indication of Case Patent Application No. 43866, 1988 2, Invention Imaging device 3° Relationship to the case of the person making the amendment Patent Applicant Location Name of the place (432), 3-12i Moriya-cho, Kanayō-ku, Yokohama-shi, Kanagawa Prefecture Victor Company of Japan Co., Ltd. 4, Agent 5, Amendment order Date: August 30, 1989 (Shipping port: September 1211, 1989)
6. Subject of amendment Column 7: Contents of amendment in the written procedural amendment submitted on March 15, 1989. Contents of amendment

Claims (1)

[Claims] 1. An optical device comprising at least a photoconductive layer member, a dielectric mirror, and a light modulating material layer member between two transparent electrodes.
A means for causing light from a subject to enter the photoconductive layer member side of the light conversion element to generate a charge image corresponding to an optical image of the subject in the light-to-light conversion element; and a light modulating material layer member of the light-to-light conversion element. means for reading out a charge image corresponding to the optical image of the subject as optical information by readout light incident on the light-to-light conversion element from the side; and means for erasing the charge image corresponding to the optical image of the subject. In an imaging device that is equipped with a charge image erase operation and a charge image readout operation that are repeated intermittently, the readout operation is performed during a part of the period excluding the period in which the charge image erase operation is performed. An imaging device 2 comprising means for outputting only a signal corresponding to the optical information obtained, and comprising at least a photoconductive layer member, a dielectric mirror, and a light modulating material layer member between two transparent electrodes. Light composed of -
A means for causing light from a subject to enter the photoconductive layer member side of the light conversion element to generate a charge image corresponding to an optical image of the subject in the light-to-light conversion element; and a light modulating material layer member of the light-to-light conversion element. means for reading out a charge image corresponding to the optical image of the subject as optical information by readout light incident on the light-to-light conversion element from the side; and means for erasing the charge image corresponding to the optical image of the subject. In an imaging device that is equipped with a charge image erase operation and a charge image readout operation that are repeated intermittently, light from a subject is incident on a light-to-light conversion element through an optical shutter. and means for outputting only a signal corresponding to the optical information read during the period when the light incident on the light-to-light conversion element is blocked by the optical shutter.