JP2850611B2 - Optical information processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual device, such as an industrial robot, for filtering an input image in the spatial frequency domain, performing image processing for feature extraction, or identifying an input image that matches a specific standard pattern. The present invention relates to an optical information processing device that performs a process to be performed.

[0002]

2. Description of the Related Art In recent years, optical information processing technology has been applied, but there is a problem of miniaturization and weight reduction of the device.

Hereinafter, a conventional optical information processing apparatus will be described with reference to the drawings. FIG. 7 is a schematic diagram showing a configuration of a conventional optical information processing apparatus. In the figure, reference numeral 1 denotes a semiconductor laser, 2 denotes a collimator lens for converting light from the semiconductor laser 1 into parallel light, and 3 denotes a television camera (hereinafter referred to as a TV).
Reference numeral 13 denotes a liquid crystal display for displaying an image picked up by the TV camera 3, and reference numeral 6 denotes a lens. The liquid crystal display 13 is disposed on the front focal plane of the lens 6. Reference numeral 8 denotes a memory for storing data of Fourier transform computer generated holograms of a plurality of standard patterns, and reference numeral 14 denotes a liquid crystal display, which is arranged on a rear focal plane of the lens 6. Reference numeral 11 denotes a lens, and a liquid crystal display 14 is disposed on the front focal plane. 12 is lens 1
1 is a photoelectric conversion device disposed on the rear focal plane.

[0004] The interrelationship and operation of the above components will be described below. The pattern of the object displayed on the liquid crystal display 13 is irradiated with coherent light from the semiconductor laser 1. This target object image is optically converted by the lens 6, and a Fourier transform image of the target object is formed on the liquid crystal display 14. At this time, the Fourier transform image of the standard pattern written in the RM 8 is displayed on the liquid crystal display 14. Therefore, the light emitted from the liquid crystal display 14 is the optical product of the target object and two Fourier transform images of the specific standard pattern. Since the liquid crystal display 14 is disposed on the front focal plane of the lens 11, the image is subjected to Fourier inverse transform by the lens 11.

When the Fourier transform image of the target object matches the Fourier transform image of the standard pattern, a bright spot is generated on the rear focal plane of the lens 11 and detected by the photoelectric conversion device 12. In this way,
An optical information processing apparatus that performs an optical correlation process in which an optical filter based on a computer generated hologram displayed on the liquid crystal display 14 acts as a matched filter can be realized.

FIG. 8 shows the liquid crystal display 13 shown in FIG.
And 14 are shown in perspective view. In the figure,
Polarizing plates 15 and 17 are provided before and after a liquid crystal cell 16 for displaying an image.
Is arranged.

[0007]

In such a conventional optical information processing apparatus, the liquid crystal display 13 and the liquid crystal display 14 are arranged side by side, so that the light emitted from the liquid crystal display 13 and the light incident on the liquid crystal display 14 are combined. By aligning the directions, it is easily conceivable to omit the incident-side polarizing plate of the liquid crystal display 14, that is, the polarizing plate 15 in FIG. However, variations in the thickness and alignment direction of the liquid crystal layer of the liquid crystal display at the time of manufacturing cause a difference in the incident light direction of the liquid crystal display 14, lowering the contrast in the liquid crystal display 14 and lowering the shape recognition accuracy in pattern matching. There was a problem.
For this reason, a polarizing plate is used on the incident side of the liquid crystal display 14. A dichroic polarizer that is easy to reduce in size and weight is used as the polarizing plate, and has a transmittance of 7 in the transmission axis direction.
Since it is as low as 0 to 80%, the signal intensity in the photoelectric conversion device 2 becomes small, the S / N deteriorates, and the recognition accuracy in pattern matching decreases. Further, when the laser power is increased to increase the signal strength, there is a problem that the life of the semiconductor laser is shortened.

An object of the present invention is to provide an optical information processing apparatus in which the shape recognition accuracy in pattern matching is improved by eliminating light absorption by a polarizing plate and improving light use efficiency. Aim.

[0009]

According to the present invention, in order to achieve the above object, a first object of the present invention is to provide a first liquid crystal cell for displaying a first image and a first liquid crystal cell. A coherent linearly polarized light source to be illuminated, a first polarizing plate having incident light from the first liquid crystal cell, a half-wave plate having incident light from the first polarizing plate, A first lens having a surface on which the first liquid crystal cell is placed as a front focal plane, and a second liquid crystal cell disposed at a rear focal plane of the first lens and displaying a second image A second polarizing plate that makes incident light of the second liquid crystal cell an incident light;
An optical information processing apparatus comprising: a second lens having a rear focal plane as a front focal plane of the second lens; and a photoelectric conversion device located at a rear focal plane of the second lens. The first problem solving means comprises: a first liquid crystal cell for displaying a first image; a coherent linearly polarized light source for irradiating the first liquid crystal cell; A first polarizing plate, and a second light source of a homogeneous type in which the light emitted from the first polarizing plate is incident light, and the alignment direction of the liquid crystal forms an angle of approximately 45 degrees with the light emitted from the first polarizing plate. A liquid crystal cell, a 射出 wavelength plate having an emission axis of the second liquid crystal cell as incident light, an optical axis of which is substantially parallel to a transmission axis of the first polarizing plate, and a position of the first liquid crystal cell. A first lens having the front surface as the front focal plane, a second lens disposed at the rear focal plane of the first lens, A third liquid crystal cell for displaying an image,
A second polarizing plate having incident light as emission light of the third liquid crystal cell, a second lens having a rear focal plane as a front focal plane of the first lens, and a second lens having a rear focal plane as a front focal plane. Optical information processing device comprising a photoelectric conversion device located on the side focal plane,
Further, a third object of the present invention is to provide a first liquid crystal cell for displaying a first image, a coherent linearly polarized light source for irradiating the first liquid crystal cell, and an emission of the first liquid crystal cell. A first polarizer having light as incident light; and a homogeneous polarizer having an exit direction of the first polarizer as incident light and an orientation direction of a liquid crystal forming an angle of approximately 45 degrees with a transmission axis of the first polarizer. A second liquid crystal cell of the type and incident light of the light emitted from the second liquid crystal cell, the orientation direction of the liquid crystal makes an angle of approximately 135 degrees with the transmission axis of the first polarizing plate, and the thickness of the liquid crystal layer And a third homogeneous liquid crystal cell substantially equal to the second liquid crystal cell, and a first liquid crystal cell whose emission axis is the incident light and whose optical axis is substantially parallel to the transmission axis of the first polarizing plate.レ ン ズ wavelength plate and a first lens having a surface on which the first liquid crystal cell is placed as a front focal plane A fourth liquid crystal cell disposed on a rear focal plane of the first lens and displaying a second image, a second polarizer that uses incident light from the fourth liquid crystal cell, An optical information processing apparatus comprising: a second lens having a rear focal plane as a front focal plane of the first lens; and a photoelectric conversion device located at a rear focal plane of the second lens.

[0010]

According to the present invention, in the above construction, the first problem solving means comprises a half-wave plate, and the second problem solving means comprises a homogeneous second liquid crystal cell and a quarter wave plate. According to a third means for solving the problem, the second and third homogeneous types are used.
Liquid crystal cell and a quarter-wave plate convert the polarization axis direction of the emitted light of the liquid crystal cell displaying the first image so as to match the incident polarization axis direction of the liquid crystal cell displaying the second image. This eliminates the need for a polarizing plate provided on the front side of the liquid crystal display for optical product generation in the conventional device, and reduces light absorption by the polarizing plate.

[0011]

(Embodiment 1) Hereinafter, an optical information processing apparatus according to one embodiment of the first problem solving means of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of the optical information processing apparatus of the embodiment. In the figure, the same components as those of the conventional example shown in FIG. Reference numeral 4 denotes a liquid crystal cell for displaying an image picked up by the TV camera 3, which is arranged on the front focal plane of the lens 6. Reference numeral 5 denotes an output side polarizing plate of the liquid crystal cell 4, and reference numeral 9 denotes a liquid crystal cell, which is disposed on a rear focal plane of the lens 6. Reference numeral 10 denotes an output-side polarizing plate of the liquid crystal cell 9. Reference numeral 25 denotes a half-wave plate whose optical axis is perpendicular to the optical axis and is on a bisector of an angle formed between the direction of the transmission axis of the polarizing plate 5 and the direction of incidence of the liquid crystal cell 9.

Hereinafter, the interrelationship and operation of the above components will be described. The pattern of the target object displayed on the liquid crystal cell 4 is irradiated with coherent light from the semiconductor laser 1. The light emitted from the liquid crystal cell 4 becomes an object image of linearly polarized light by the polarizing plate 5. The direction of the linearly polarized light is converted by the half-wave plate 25 into the incident direction of the liquid crystal cell 9. 1
The light emitted from the half-wave plate 25 is optically converted by the lens 6 to form a Fourier transform image of the target object on the liquid crystal cell 9. At this time, a Fourier transform image of the standard pattern written in the ROM 8 is displayed on the liquid crystal cell 9. The light emitted from the liquid crystal cell 9 by the polarizing plate 10 becomes an optical product of two Fourier transform images of the target object and a specific standard pattern. Since the liquid crystal cell 9 is disposed on the front focal plane of the lens 11, this image is subjected to Fourier inverse transform by the lens 11. When the Fourier transform images of the target object and the standard pattern match, a bright spot is generated on the rear focal plane of the lens 11 and detected by the photoelectric conversion device 12. In this way,
An optical information processing device that performs optical information processing in which an optical filter based on a computer generated hologram displayed on the liquid crystal cell 9 acts as a matched filter can be realized.

Next, the half-wave plate 25 causes the polarizing plate 5
The operation of converting the emitted light into the incident direction of the liquid crystal cell 9 will be described. FIG. 2 shows a polarizing plate 5, a liquid crystal cell 9, and 1
The optical direction relationship of the half-wave plate is shown in a vector diagram. In the figure, reference numeral 40 denotes the direction of the transmission axis of the polarizing plate 5, and this direction is used as a reference. Reference numeral 41 denotes the incident polarization direction of the liquid crystal cell 9, and the azimuth is ra. Reference numeral 42 denotes the optical axis direction of the half-wavelength polarizing plate 25, and the azimuth is ra / 2. The state of the light emitted from the half-wave plate 25 when the light emitted from the polarizing plate 5 is incident will be described using the Jones vector.

The Jones vector Ea of the incident light on the half-wave plate 25 is

[0015]

(Equation 1)

## EQU1 ## The matrix C0 of the half-wave plate whose optic axis is oriented is

[0017]

(Equation 2)

## EQU1 ## Assuming that a matrix for rotating the optical element by θ is R (θ),

[0019]

(Equation 3)

## EQU1 ## The matrix C when the half-wave plate is rotated by ra / 2 is

[0021]

(Equation 4)

## EQU1 ## This half-wave plate has a vector Ea
The outgoing light Eb when

[0023]

(Equation 5)

## EQU1 ## This vector indicates linearly polarized light in the azimuth ra. That is, the light emitted from the polarizing plate 5 is converted by the 波長 wavelength plate 25 in the direction of incidence on the liquid crystal cell 9. Since the transmittance of the half-wave plate is 99% or more, the light efficiency is about 1.3 times that of the means using the conventional polarizing plate.

As described above, according to the optical information processing apparatus of the embodiment of the first means for solving the problem of the present invention, by providing a half-wave plate and performing conversion so that the polarization axis direction is matched, the light Efficiency can be improved, and shape recognition accuracy by pattern matching can be improved. Furthermore, since a low-power laser can be used by improving the light efficiency, the reliability of the semiconductor laser can be improved, and the optical information processing apparatus can be downsized by downsizing the cooling unit.

(Embodiment 2) An optical information processing apparatus according to an embodiment of the second means for solving the problem of the present invention will be described below with reference to the drawings. FIG. 3 is a schematic diagram illustrating the configuration of the optical information processing apparatus according to the embodiment. In the figure, the same components as those in the first embodiment shown in FIG. Reference numeral 30 denotes a homogeneous type liquid crystal cell, in which the alignment direction of the liquid crystal forms an angle of 45 degrees with the transmission axis direction of the polarizing plate 5. 3
Reference numeral 1 denotes a １ ／ wavelength plate whose optical axis is perpendicular to the optical axis and parallel to the transmission axis of the polarizing plate 5.

Hereinafter, the interrelationship and operation of the above components will be described. FIG. 4 is a vector diagram showing the optical direction relationship among the polarizing plate 5, the liquid crystal cell 9, the liquid crystal cell 30, and the quarter-wave plate. In the figure, reference numeral 40 denotes the direction of the transmission axis of the polarizing plate 5, and this direction is used as a reference. Reference numeral 41 denotes the incident polarization direction of the liquid crystal cell 9, and the azimuth is ra. Reference numeral 50 denotes a liquid crystal alignment direction of the liquid crystal cell 30, and reference numeral 51 denotes a ３１ wavelength plate 31.
And is parallel to the transmission axis of the polarizing plate 5.

The direction of the light emitted from the polarizing plate 5 is adjusted by the liquid crystal cell 30 and the quarter-wave plate 31 to the direction r of the incident light of the liquid crystal cell 9.
It is explained that it is converted to a.

Assuming that the homogeneous liquid crystal cell 30 has a refractive index anisotropy of Δn, a liquid crystal layer thickness of d, a wavelength of the semiconductor laser 1 of λ, and δ = 2π △ nd / λ, the orientation direction of the azimuth 0 The Jones matrix J0 of the liquid crystal cell 30 is

[0030]

(Equation 6)

## EQU1 ## The matrix J of azimuth π / 4 is

[0032]

(Equation 7)

## EQU1 ## The matrix D of a quarter-wave plate with an azimuth of 0 is

[0034]

(Equation 8)

## EQU2 ## Assuming that the emission light Ea of the polarizing plate 5 is (Equation 1), the emission light Eb of the 波長 wavelength plate 31 is

[0036]

(Equation 9)

Is as follows. This polarized light is linearly polarized light having an azimuth of δ / 2. Therefore, by selecting the product △ nd of the refractive index anisotropy of the liquid crystal cell 30 and the thickness of the liquid crystal layer so that ra = δ / 2, the light emitted from the polarizing plate 5 is directed in the direction of the incident light to the liquid crystal cell 9. Can be converted.

As described above, according to the optical information processing apparatus of the embodiment of the second means for solving the problem of the present invention, the liquid crystal cells 30 and 1 /
By providing the four-wavelength plate 31 and matching the polarization axis directions, the same effect as in the first embodiment can be obtained.

Further, by applying a voltage to the homogeneous liquid crystal cell 30, δ can be reduced. Here, the maximum value of the incident direction ra of the liquid crystal cell 9 with respect to the transmission axis direction of the polarizing plate 5 caused by a manufacturing error of the liquid crystal is W. The product Δnd of the refractive index anisotropy of the liquid crystal cell 30 and the thickness of the liquid crystal layer that satisfies W ≦ 2π 選 ぶ nd / λ is selected. By applying a voltage to the liquid crystal cell 30 to reduce δ with respect to the variation in ra, the light emitted from the 波長 wavelength plate can be directed to the incident light direction of the liquid crystal cell 9. That is, it is possible to easily adjust the variation in ra by applying the voltage applied to the liquid crystal cell 30. Therefore, a decrease in contrast in the liquid crystal cell 9 can be prevented, and a decrease in shape recognition accuracy in pattern matching can be prevented.

(Embodiment 3) An optical information processing apparatus according to an embodiment of the third problem solving means of the present invention will be described below with reference to the drawings. FIG. 5 is a schematic diagram showing the configuration of the optical information processing apparatus of the embodiment. In the figure, the same components as those of the first embodiment shown in FIG. Reference numeral 36 denotes a homogeneous type liquid crystal cell, and the alignment direction of the liquid crystal forms an angle of 135 degrees with the transmission axis of the polarizing plate 5.

Hereinafter, the interrelationship and operation of the above components will be described. FIG. 6 is a vector diagram showing the optical direction relationship among the polarizing plate 5, the liquid crystal cell 9, the liquid crystal cell 30, the liquid crystal cell 36, and the quarter-wave plate. In the figure, reference numeral 40 denotes the direction of the transmission axis of the polarizing plate 5, which is used as a reference for this direction. Reference numeral 41 denotes the incident light direction of the liquid crystal cell 9, and the direction is represented by ra. 6
1 is the alignment direction of the liquid crystal cell 36.

Next, the liquid crystal cell 30, the liquid crystal cells 36 and 1
The fact that the azimuth of the light emitted from the polarizing plate 5 is converted into the azimuth ra of the incident light of the liquid crystal cell 9 by the quarter-wave plate 31 will be described.

When the anisotropy of the refractive index of the homogeneous type liquid crystal cell 30 is Δn, the thickness of the liquid crystal layer is d, the wavelength of the semiconductor laser 1 is δ, and δ = 2π △ nd / λ, the orientation direction is azimuth π / Jones matrix J of the liquid crystal cell 30 of No. 4
Becomes (Equation 7). The refractive index anisotropy of the liquid crystal cell 36
Assuming that n and the thickness of the liquid crystal layer are da and da = 2π △ nd / λ, the matrix K of the liquid crystal cell 36 having the azimuth of ／ π is

[0044]

(Equation 10)

Is as follows. The matrix D of the quarter-wave plate having the azimuth 0 is represented by (Equation 7). Assuming that the emission light Ea of the polarizing plate 5 is (Equation 1), the emission light Eb of the 波長 wavelength plate 31 is

[0046]

[Equation 11]

Is as follows. This polarized light has an orientation of δ / 2−δa /
2 shows linearly polarized light. Therefore, ra = δ / 2
−δa / 2 so that the liquid crystal cell 30 and the liquid crystal cell 36
By selecting the products △ nd and △ nda of the refractive index anisotropy and the thickness of the liquid crystal layer, the light emitted from the polarizing plate 5 can be converted to the incident direction of the liquid crystal cell 9. Further, if the thicknesses and orientation directions of the liquid crystal layers of the liquid crystal cell 4 and the liquid crystal cell 9 are selected so that ra becomes substantially 0, and the thicknesses of the liquid crystal layers of the liquid crystal 30 and the liquid crystal 36 are selected to be substantially equal, δ / 2 Since −δa / 2 = π △ n (d−da) / λ, the value of Δn is reduced, so that the influence of the temperature dependence of the refractive index anisotropy Δn of the liquid crystal can be reduced.

As described above, according to the optical information processing apparatus of the third embodiment of the present invention, the liquid crystal cell 30, the liquid crystal cell 36 and the quarter-wave plate 31 are provided so that the directions of the polarization axes coincide. By doing so, the same effect as in the first embodiment can be obtained. Furthermore, the fluctuation of the temperature of the liquid crystal cell 30 due to the fluctuation of the azimuth of the emitted light from the quarter-wave plate can be reduced by making the thicknesses of the liquid crystal cell 30 and the liquid crystal cell 36 substantially equal.

In the first embodiment, the half-wave plate 25 may be replaced by two quarter-wave plates.

[0050]

As is apparent from the above embodiments, the present invention provides, as a first means for solving the problems, a first liquid crystal cell for displaying a first image, and a coherent light for irradiating the first liquid crystal cell. A linearly polarized light source, a first polarizing plate having incident light from the first liquid crystal cell, a half-wave plate having incident light from the first polarizing plate, A first lens having a surface on which the liquid crystal cell is placed as its front focal plane;
A second liquid crystal cell disposed on a rear focal plane of the first lens and displaying a second image, a second polarizing plate configured to emit light from the second liquid crystal cell as incident light, An optical information processing apparatus including a second lens having a rear focal plane on a rear focal plane of the first lens and a photoelectric conversion device located on a rear focal plane of the second lens; As two means for solving the problems, a first liquid crystal cell for displaying a first image, a coherent linearly polarized light source for irradiating the first liquid crystal cell, and light emitted from the first liquid crystal cell as incident light. A first polarizing plate, and a homogeneous second liquid crystal in which the light emitted from the first polarizing plate is incident light and the orientation direction of the liquid crystal forms an angle of approximately 45 degrees with the light emitted from the first polarizing plate. Light emitted from the cell and the second liquid crystal cell is incident light, and an optical axis is a transmission axis of the first polarizing plate. And substantially parallel quarter-wave plate, are arranged placed faces of the first liquid crystal cell and the first lens to a front focal plane, the back focal plane of said first lens,
A third liquid crystal cell for displaying a second image, a second polarizer having incident light from light emitted from the third liquid crystal cell, and a back focal plane of the first lens being a front focal plane. An optical information processing device including a second lens to be used and a photoelectric conversion device located at a rear focal plane of the second lens, and displays a first image as a third means for solving the problem. A first liquid crystal cell, a coherent linearly polarized light source that irradiates the first liquid crystal cell, a first polarizing plate that uses light emitted from the first liquid crystal cell as incident light, and a first polarizing plate that emits light. Emitting light is incident light, and a homogeneous second liquid crystal cell in which the orientation direction of the liquid crystal forms an angle of approximately 45 degrees with the transmission axis of the first polarizing plate, and the light emitted from the second liquid crystal cell is incident. And the liquid crystal orientation direction is substantially 135 degrees with the transmission axis of the first polarizing plate. And a third homogeneous liquid crystal cell having a thickness substantially equal to that of the second liquid crystal cell, and an emission light of the third liquid crystal cell as incident light, and an optical axis substantially parallel to a transmission axis of the first polarizing plate. A first quarter-wave plate, a first lens having a surface on which the first liquid crystal cell is placed as a front focal plane, and a second lens disposed on a rear focal plane of the first lens. A fourth liquid crystal cell for displaying, a second polarizing plate that uses incident light of the light emitted from the fourth liquid crystal cell, and a second lens that uses a rear focal plane of the first lens as a front focal plane When,
With the optical information processing apparatus including the photoelectric conversion device located on the rear focal plane of the second lens, the light efficiency can be improved, and the shape recognition accuracy by pattern matching can be improved. Further, by improving the light efficiency, a low-power laser can be used, the reliability of the semiconductor laser can be improved, and the device can be downsized by downsizing the cooling unit.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of an optical information processing apparatus according to an embodiment of a first problem solving means of the present invention;

FIG. 2 is a vector diagram showing an optical direction relationship between a polarizing plate and a half-wave plate in the embodiment.

FIG. 3 is a schematic diagram showing a configuration of an optical information processing apparatus according to an embodiment of the second problem solving means of the present invention;

FIG. 4 shows a polarizing plate, a liquid crystal cell and 1 /
Vector diagram showing the optical direction relationship of the four-wave plate

FIG. 5 is a schematic diagram showing a configuration of an optical information processing apparatus according to an embodiment of the third problem solving means of the present invention.

FIG. 6 shows a polarizing plate, a liquid crystal cell, and 1 /
Vector diagram showing the optical direction relationship of the four-wave plate

FIG. 7 is a schematic diagram showing a configuration of a conventional optical information processing apparatus.

FIG. 8 is a perspective view showing a configuration of a liquid crystal cell.

[Explanation of symbols]

 Reference Signs List 1 semiconductor laser (coherent linearly polarized light source) 2 collimator lens (coherent linearly polarized light source) 3 TV camera (first image source) 4 liquid crystal cell (first liquid crystal cell) 5 polarizing plate (first polarizing plate) 6 lens (First lens) 8 ROM (second image source) 9 liquid crystal cell (second liquid crystal cell) 10 polarizing plate (second polarizing plate) 11 lens (second lens) 12 photoelectric conversion device 25 1 / 2-wavelength plate

Claims (3)

(57) [Claims] 1. A first liquid crystal cell for displaying a first image, a coherent linearly polarized light source for irradiating the first liquid crystal cell, and a first liquid crystal for emitting light from the first liquid crystal cell as incident light. A polarizing plate, a half-wave plate that uses the light emitted from the first polarizing plate as incident light, a first lens whose front focal plane is the surface on which the first liquid crystal cell is placed, and A second liquid crystal cell disposed on a rear focal plane of the first lens and displaying a second image, a second polarizing plate configured to emit light from the second liquid crystal cell as incident light, An optical information processing apparatus comprising: a second lens having a rear focal plane on a rear focal plane of a first lens; and a photoelectric conversion device located on a rear focal plane of the second lens. 2. A first liquid crystal cell for displaying a first image, a coherent linearly polarized light source that irradiates the first liquid crystal cell, and a first liquid crystal that emits light from the first liquid crystal cell as incident light. And a homogenous second liquid crystal cell in which the light emitted from the first polarizing plate is incident light and the orientation direction of the liquid crystal forms an angle of approximately 45 degrees with the light emitted from the first polarizing plate. A quarter-wave plate whose optical axis is substantially parallel to the transmission axis of the first polarizing plate, and a surface on which the first liquid crystal cell is placed, wherein the emission light of the second liquid crystal cell is incident light. A first lens serving as a front focal plane, a third liquid crystal cell arranged on the rear focal plane of the first lens for displaying a second image, and light emitted from the third liquid crystal cell being incident thereon. A second polarizing plate having light, a second lens having a rear focal plane on the rear focal plane of the first lens, and a second lens having a front focal plane on the second lens. And a photoelectric conversion device located at the rear focal plane of the lens. 3. A first liquid crystal cell for displaying a first image, a coherent linearly polarized light source for irradiating the first liquid crystal cell, and a first liquid crystal for emitting light from the first liquid crystal cell as incident light. And a homogenous second liquid crystal cell in which the liquid crystal orientation direction forms an angle of approximately 45 degrees with the transmission axis of the first polarizer, with the light emitted from the first polarizer as incident light. The emitted light of the second liquid crystal cell is used as incident light, the alignment direction of the liquid crystal forms an angle of approximately 135 degrees with the transmission axis of the first polarizing plate, and the thickness of the liquid crystal layer is equal to that of the second liquid crystal cell. A third homogeneous liquid crystal cell substantially equal to the first liquid crystal cell, a ４ wavelength plate having an emission axis of the third liquid crystal cell as incident light, and an optical axis substantially parallel to a transmission axis of the first polarizing plate; A first lens having a surface on which one liquid crystal cell is placed as a front focal plane; A fourth liquid crystal cell disposed on the side focal plane and displaying a second image, a second polarizing plate that uses light emitted from the fourth liquid crystal cell as incident light, and a rear side of the first lens A second lens having a focal plane as a front focal plane;
An optical information processing apparatus comprising: a photoelectric conversion device located on a rear focal plane of the second lens.