JPH07218928A - Spatial optical modulation device and writer for the same - Google Patents

Abstract

PURPOSE:To facilitate high-resolution write and read in a spatial optical modulation device for writing and reading optical information. CONSTITUTION:This device is provided with first electrode parts 3 and 3', variable resistor means 2 and 2' provided in areas larger than those of the first electrode parts 3 and 3' for each of first electrode parts 3 and 3' so as to change resistance values from the outside, second electrode part 10 provided on a face different from the face where the first electrode parts 3 and 3' are existent confronting the first electrode parts 3 and 3', and light modulating part 12 provided between the first electrode parts 3 and 3' and the second electrode part 10 so as to decide the state of changing the characteristics of light depending on a voltage between both the electrodes. Then, the characteristics of light with which the optical modulation part 12 is irradiated are changed according to the state of the optical modulation part 12 based on the voltage, which is decided according to the resistance values of the variable resistor parts 2 and 2', between the first electrode parts 3 and 3' and the second electrode part 10 by changing the resistance values of the variable resistor parts 2 and 2' from the outside and impressing the voltage between the first electrode parts 3 and 3' and the second electrode part 10 through the variable resistor parts 2 and 2'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spatial light modulator for writing and reading optical information in a stereoscopic display device, an optical computer for processing image information and the like using a hologram.

By irradiating a hologram with coherent readout light (reproduction light) such as laser light, it is possible to reproduce a stereoscopic image or read out information written in the hologram. The hologram may be created by printing the coherent light on a photographic dry plate, or a display device such as a liquid crystal may be used to display the pattern of the coherent light.

The present invention relates to a spatial light modulator for displaying a hologram by using liquid crystal or the like and irradiating read light to read written information.

[0004]

2. Description of the Related Art FIG. 7 shows a conventional reflective spatial light modulator using a liquid crystal. In FIG. 7, 110 is a surface protective layer, such as protective glass.

Reference numeral 111 is a transparent electrode, such as ITO. Reference numeral 112 denotes an alignment layer, which is a liquid crystal alignment layer provided on the surface protection layer 110.

Reference numeral 113 is a liquid crystal. Reference numeral 114 denotes an alignment layer, which is a liquid crystal alignment layer provided on the back surface protective layer (glass substrate) 119.

Reference numeral 115 is a dielectric mirror which reflects the read light incident through the surface protective layer 110. Reference numeral 116 denotes a light shielding layer, which is a back surface protective layer 119.
The surface protection layer 1 that blocks the writing light that is incident through the
It is to prevent the light from penetrating to the 10 side.

Reference numeral 117 denotes a photoconductive film which changes its resistance value when irradiated with light (the resistance value of a portion exposed to light decreases). Reference numeral 118 is a transparent electrode, such as ITO.

Reference numeral 119 is a back surface protective layer, which is a glass substrate. In the above configuration, the transparent electrodes 111 and 118
Is an electrode common to each area for displaying a hologram (a liquid crystal area for displaying a hologram in dot units).

The operation of the configuration shown in FIG. 7 will be described. Liquid crystal 113
A liquid crystal drive voltage is applied between the two transparent electrodes (111) and (118) sandwiching the two electrodes.

When information is written (hologram is displayed), diffracted light for forming a hologram is applied to the entire surface of the back surface protective layer 119 as writing light. The writing light passes through the transparent electrode 118 and the photoconductive film 11
The entire surface of 7 is irradiated. The resistance value of the photoconductive film 117 in the portion irradiated with light (the bright portion of the irradiation light) becomes low. Therefore, the voltage between the photoconductive film 117 and the transparent electrode (111) in the part not irradiated with light (the dark part of the irradiation light) and the voltage between the photoconductive film 117 and the transparent electrode 111 in the part irradiated with light are Will be different. Therefore, the alignment state of the liquid crystal is different in the liquid crystal 113 between the light-irradiated portion and the light-unirradiated portion, and the liquid crystal orientation distribution corresponding to the hologram is obtained, and the written hologram is displayed. .

The reflective spatial light modulator comprises a surface protective layer 1
The content of the displayed hologram is read out by irradiating the reading light from the side of 10 to reproduce a stereoscopic image.

Next, the read operation will be described. The liquid crystal 113 is irradiated with the reading light through the surface protective layer 110 and the transparent electrode 111, and the liquid crystal 113 is transmitted through the dielectric mirror 1.
Reflect at 15. Then, the reflected light is transmitted through the liquid crystal 113, the transparent electrode 111, and the surface protection layer 110 and emitted. The read light is modulated by the alignment state of the liquid crystal while passing through the liquid crystal. Therefore, the content of the hologram is read out by the reflected light that is reflected and emitted, and a stereoscopic image or the like is reproduced.

[0014]

In order to display a high-precision hologram, it is necessary to display with a resolution on the order of micron. On the other hand, in a conventional spatial light modulator using a liquid crystal display device, the display resolution can be increased by thinning the liquid crystal, but when the liquid crystal is thinned to a high resolution hologram display of the order of microns, the liquid crystal is driven. It becomes difficult to apply a high voltage required for liquid crystal between the liquid crystals. Further, in order to write such a highly accurate hologram, the spot size of the writing light needs to be 1 micron or less, and a highly accurate writing device is required.

The present invention provides a spatial light modulator capable of performing high-precision hologram display in pixel units and easily performing high-resolution writing without using a high-precision writing device. To aim.

[0016]

According to the present invention, a display unit is spatially and finely separated by forming a pixel unit by finely divided electrode portions, and a high resolution is obtained even if a liquid crystal or the like is formed thickly. Made it possible to display. Further, a variable resistance portion (photoconductive portion) is provided for each fine electrode, and the area of the variable resistance portion is made larger than the area of the electrode portion so that writing can be performed easily.

FIG. 1 shows a basic configuration (1) of the present invention. Figure 1
1 (a) is a plan view, and FIG. 1 (b) is X in the plan view (a).
It is a sectional view of Y.

In FIGS. 1A and 1B, 1 is a spatial light modulator. Reference numerals 2 and 2 ′ are variable resistance parts (photoconductive parts), which are composed of, for example, photoconductive films.

Reference numerals 3 and 3'represent first electrode portions, which are electrodes for each pixel of the light modulation portion (liquid crystal) 12. Four
Is a power supply line 1 for supplying a voltage to the first electrode portion 3.

Reference numeral 4'denotes a power supply line 1'for supplying a voltage to the first electrode portion 3 '. A surface layer 8 is, for example, a liquid crystal alignment layer (hereinafter referred to as the first electrode portion (3)).
, The side with (3 ') is the surface).

Reference numeral 8'denotes a back surface layer, which is, for example, an alignment layer of liquid crystal (hereinafter, the side having the second electrode portion (transparent electrode) is a back surface). .

Reference numeral 10 is a second electrode portion, which is, for example, a transparent electrode. The second electrode section 10 is an electrode common to each pixel area of the light modulation section 12. Reference numeral 12 is a light modulator, which is, for example, a liquid crystal.

In the configuration of FIG. 1, the power supply line 1 (4), the variable resistance portion 2 and the first electrode portion 3 are electrically connected.
In addition, the power supply line 1 '(4'), the variable resistance portion 2 ', and the first electrode portion 3'are electrically connected. Further, a light-shielding layer is required on the back side of the variable resistance portions 2 and 2'in order to prevent the writing light incident from the front surface from being transmitted from the back surface, but it is omitted in FIG. 1 (the light-shielding layer is the surface layer 8). Of the variable resistance part 2 or 2 '). Also, when the read light is incident from the back side,
Entire surface of the surface layer 8 (between the light shielding layer and the light modulation portion 12)
A reading light reflecting means is required for the above, but it is omitted in the figure. Further, when the reading light is emitted from the surface, the reading light reflecting means is not necessary.

The operation of the basic configuration (1) in FIG. 1 will be described later. FIG. 2 shows a basic configuration (2) of the present invention, showing a basic configuration of a writing device when writing is performed by writing light.

In FIG. 2, reference numeral 1 is a spatial light modulator. Reference numerals 2, 2 ′ and 2 ″ are variable resistance portions (photoconductive portions), which are composed of, for example, photoconductive films.

Reference numeral 20 is a writing device for writing the stored information in the spatial light modulator 1. Reference numeral 21 is a writing light generating means for generating writing light.

Numeral 22 is a scanning means for writing light, which is used for scanning the spot of writing light on each variable resistance portion (photoconductive portion) 2,
The scanning is performed so that the light beams 2'and 2 "are sequentially incident. Reference numeral 23 is a writing control means, which controls the writing light generating means 21 and the writing light scanning means 22.

In the above structure, the writing light generating means (21) may be composed of a plurality of light emitting elements so as to simultaneously generate a plurality of light beams. The operation of the basic configuration (2) of the present invention in FIG. 2 will be described later.

[0029]

The operation of the basic configuration (1) of the present invention shown in FIG. 1 will be described. (1) Writing When a write signal is input to the variable resistance units 2 and 2 ', the resistance of the variable resistance units 2 and 2'is changed according to the write signal.
For example, when the variable resistance portions 2 and 2'are made of a photoconductive film, the writing light is incident on each variable resistance portion 2 and 2 '. The electric resistance of the variable resistance portions 2 and 2'on which the light is incident decreases. Therefore, the variable resistance part 2, which is irradiated with light,
The voltage between the first electrode portion 3 and 3 ′ connected to 2 ′ and the second electrode portion 10 becomes high. In addition, the resistance of the variable resistance portions 2 and 2 ′ not irradiated with light remains high, and the first electrode portions 3 and 3 ′ and the second electrode portions connected to the variable resistance portions 2 and 2 ′ are kept. The voltage during 10 will be low. As a result, the state of the light modulation section 12 between the first electrode section 3, 3'and the second electrode section 10 changes depending on the presence or absence of incident light and the intensity of the variable resistance section 2, 2 '. When the light modulator 12 is made of liquid crystal, for example, the alignment state changes.

(2) Readout Readout light is incident from the back surface. The read light is transmitted through the second electrode portion 10 to enter the light modulation portion 12, is transmitted through the front surface side and is emitted, or is reflected when a reflecting means is provided on the front surface side and is reflected from the back surface side. Is emitted.

While the read light is transmitted through the light modulator 12, the characteristics of the read light (amplitude, phase, polarization state of light, etc.) of each pixel region of the light modulator 12 depend on the state of the light modulator 12 (writing information). It is possible to read the written information that has changed according to (there is a different state). For example, when the light modulator 12 is made of liquid crystal, transmitted light or reflected light having different characteristics depending on the alignment state in each pixel region can be obtained.

According to the present invention, the display pattern can be displayed with high precision by making the first electrode portions 3 and 3 ′ minute (for example, about several microns) and the variable resistance portions 2 and 2 ′ can be displayed. Since it has a larger area than the first electrode portions 3 and 3 ', the writing light can be easily incident as a spot. Therefore, according to the present invention, high-resolution writing can be easily performed without using a high-precision writing device.

The operation of the basic configuration (2) of the present invention shown in FIG. 2 will be described. The writing control means 23 generates a writing control signal for the writing light generating means 21 in accordance with the scanning timing signal output from the spatial light modulator 1. The writing light generating means 21 generates writing light in accordance with the writing control signal. The writing light is incident on the variable resistance portion (photoconductive portion) 2 where information is to be written via a lens or the like.

The writing light scanning means 22 scans the writing light in accordance with the writing control signal, and the variable resistance section 2,
The variable resistance portion 2'and the variable resistance portion 2 "are sequentially scanned and writing is performed.

The scanning is one-dimensional or two-dimensional. Further, it is also possible to provide a plurality of light emitting elements of the writing light generating means 21 so that a plurality of writing lights can simultaneously write to a plurality of variable resistance portions 2, 2 ', 2 ".

According to the present invention, the pixel unit is spatially and finely separated by an electrode array having a fine structure to form the light modulation portion 12 thickly.
A high voltage can be applied between the first electrode portions 3 and 3'and the second electrode 10 and writing with high resolution is possible. Further, since the variable resistance part for writing information (writing hologram) is also spatially separated to have a large area, it becomes easy to write, and high resolution can be achieved without using a highly accurate writing device. It is possible to easily write the display pattern.

[0037]

EXAMPLE FIG. 3 shows Example 1 of the present invention. In FIG. 3, the photoconductive portions 42 and 42 'are arranged alternately on both sides of the electrode portion. The transmission type in which both the writing light and the reading light are incident from the front surface side is shown.

FIG. 3 (a) is a plan view, and FIG. 3 (b) is a plan view (a).
FIG. 3C shows a plan view of the common electrode (transparent electrode). In FIGS. 3A, 3B and 3C, reference numeral 41 is a spatial light modulator.

Reference numerals 42 and 42 'denote photoconductive portions, which correspond to the variable resistance portion shown in FIG. Reference numerals 43 and 43 'denote electrode portions (transparent electrodes), which correspond to the electrode portions in FIG.

Reference numeral 44 is a power supply line 1 for supplying a voltage to the transparent electrode 43. 44 'is a power supply line 1', which supplies a voltage to the transparent electrode 43 '. Four
Reference numerals 8, 48 'are alignment layers.

Reference numeral 50 is a transparent electrode (common electrode), which corresponds to the second electrode portion in FIG. A liquid crystal 52 corresponds to the light modulator of FIG.

Reference numeral 55 is a glass substrate. 55 'is a glass protective layer. Reference numeral 56 denotes a light-shielding layer which is provided on the back side of the photoconductive portion 42 so that writing light can be applied to the back surface (glass protective layer 5
5 ') to prevent permeation.

Reference numeral 56 'denotes a light shielding layer, which is the photoconductive portion 42'.
It is provided on the back surface of the device to prevent the writing light from passing through the back surface. In the configuration of FIG. 3, the power supply line 1 (4
4), the photoconductive portion 42 and the transparent electrode 43 are electrically connected. Also, the power supply line 1 '(44') and the photoconductive portion 4
2'and the transparent electrode 43 'are electrically connected. Note that FIG. 3 shows only a part of one row in the horizontal direction, in which a large number of similar configurations of the photoconductive portion and the electrode portion are arranged in the horizontal direction, and a large number of similar elements are also arranged in the vertical direction. Further, the ratio of the length of the transparent electrodes 43, 43 'in the vertical direction to the size of the photoconductive portion is not shown in the figure, but is actually longer.

In the structure of FIG. 3, the writing light is transmitted from the surface (the side of the glass substrate 55) to the photoconductive portions 42 and 42 '.
Is incident on. Readout light is also incident on the transparent electrode 43 from the front surface (the side of the glass substrate 55), transmitted through the transparent electrode 43, the alignment layer 48, the liquid crystal 52, the alignment layer 48 ', the transparent electrode 50, and the glass protective layer 55', and from the back surface. Read out. Here, when it is used as a reflective modulation element, the alignment layer 4
8 may be formed between the transparent electrode 43 and the photoconductive portion 43.

FIG. 4 shows a second embodiment of the present invention. In FIG. 4, photoconductive portions are arranged in a zigzag pattern on both sides of each electrode portion. In FIG. 4, reference numeral 41 is a spatial light modulator.

Reference numerals 42-1 and 42-2 denote photoconductive portions,
It is connected to the power line 1 (44). 42'-
1, 42'-2 are photoconductive parts, and power supply lines 1 '(4
4 ').

Reference numeral 45-1 denotes an electrode portion, which is a photoconductive portion 42.
It is connected to -1. An electrode portion 45-2 is connected to the photoconductive portion 42-2. 45 '
Reference numeral -1 is an electrode portion, which is connected to the photoconductive portion 42'-1.

Reference numeral 45'-2 is an electrode portion, which is the photoconductive portion 4
2'-2. Reference numeral 44 is a power supply line 1. 44 'is a power supply line 1'.

Incidentally, FIG. 4 shows only a part of one horizontal line. In this embodiment, since the photoconductive portions are arranged in a staggered pattern, the area of each photoconductive portion can be made larger than that of the first embodiment shown in FIG.

FIG. 5 shows a third embodiment of the present invention. FIG. 5 shows an arrangement in which a photoconductive portion can be simultaneously written on a plurality of photoconductive portions with a plurality of writing lights. In addition to arranging multiple photoconductive parts in parallel in the lateral direction and arranging them across multiple connection lines, the parts that do not require connection lines with the power supply line are insulated and only the necessary parts are electrically connected. By doing so, the area is increased.

In FIG. 5, reference numeral 41 is a spatial light modulator. 60 is a power supply line.

Reference numeral 60 'is a connection line between the power supply line 60 and the photoconductive portion 67. 61, 62, 63, 64, 65, 66, 6
Reference numerals 7, 68, 69 and 70 denote photoconductive portions. Each photoconductive portion is connected to each connection line and electrode of the power supply line 60 at the portion marked with a circle in FIG. 5, and is electrically insulated from the other connection lines.

Reference numeral 71 is an electrode. According to the configuration of FIG.
It is possible to scan five writing light beams in the horizontal direction and simultaneously write to the photoconductive portions 61, 62, 63, 65, 67 arranged in parallel.

FIG. 6 shows an embodiment of the writing device of the present invention. FIG. 6 shows that while simultaneously writing on a plurality of photoconductive portions arranged in the vertical direction by a plurality of laser beams,
The structure of the writing device which writes in each photoconductive part by scanning in a horizontal direction is shown.

In FIG. 6, reference numeral 80 denotes a laser array in which a plurality of laser light emitting elements are arranged in the vertical direction. For example, a laser light emitting element having the number of dots (pixels) in the vertical direction in one row is provided, and such a laser array is provided for all the rows of the spatial light modulator 84 (generation of writing light in FIG. 2). Equivalent to means).

Reference numeral 82 denotes a lens, which is a laser array 80.
Output light (writing light) is focused on each photoconductive portion (not shown) of the spatial light modulator 84.
In the figure, only light rays passing through the center of the lens 82 are shown, excluding the output light from the uppermost laser light emitting element of the laser array.

Reference numeral 83 denotes a horizontal scanning means for scanning the output light of the laser array 80 in the horizontal direction (corresponding to the writing light scanning means in FIG. 2). Reference numeral 84 is a spatial light modulator.

A controller 86 is a scanning signal (timing signal) sent from the spatial light modulator 84.
The scanning control of the laser array 80 and the horizontal scanning means 83 is performed based on the above (corresponding to the writing control means of FIG. 2).

Reference numeral 87 is a laser array emission control section,
The light emission of each laser light emitting element of the laser array is controlled. Reference numeral 88 denotes a horizontal scanning control unit, which controls the horizontal scanning of the horizontal scanning means 83.

Reference numeral 90 is a photoconductive portion. Laser array 80
If the number of laser light emitting elements is not equal to the number of pixels in the vertical direction of the spatial light modulator 84, it is also necessary to scan the output light in the vertical direction, but the scanning means therefor is omitted in FIG.

The operation of the configuration shown in FIG. 6 will be described. Each laser light emitting element of the laser array 80 is a laser array light emission control unit 8.
It is controlled to 7 and emits light with a required intensity. The output light of each laser light emitting element is made incident on the photoconductive portion 90 to which the respective output light should be made incident by the lens 82. The spatial light modulator 84 is provided with a marker for generating a scan start signal at the start position of each line, and outputs a scan signal (timing signal). In the controller 86, the horizontal scanning means 83 scans the output light from each laser light emitting element of the laser array 80 in the horizontal direction according to the timing signal, and writes it in each photoconductive portion 90 arranged in the vertical direction and the horizontal direction. I do.

[0062]

According to the present invention, since the display screen of the spatial light modulator is finely and spatially separated, it is possible to drive at a high voltage and display with high precision.
Further, since the variable resistance portion (photoconductive portion) for writing can also be configured in a large area, it is possible to easily write a highly accurate display (hologram) without using a highly accurate writing device.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration (1) of the present invention.

FIG. 2 shows a basic configuration (2) of the present invention.

FIG. 3 is a diagram showing Embodiment 1 of the present invention.

FIG. 4 is a diagram showing a second embodiment of the present invention.

FIG. 5 is a diagram showing Embodiment 3 of the present invention.

FIG. 6 is a diagram showing an embodiment of a writing device of the present invention.

FIG. 7 is a diagram showing a conventional spatial light modulator.

[Explanation of symbols]

 1: Spatial light modulator 2: Variable resistance part (photoconductive part) 2 ': Variable resistance part (photoconductive part) 3: First electrode part 3': First electrode part 4: Power supply line 1 4 ': Power line 1'8: Front surface layer (alignment layer) 8 ': Back surface layer (alignment layer) 10: Second electrode portion (transparent electrode) 12: Light modulation portion (liquid crystal)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuko Sato 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (7)

[Claims] 1. A first electrode part (3), (3 ') and an area larger than the first electrode part (3), (3'),
Variable resistance parts (2) and (2 ′) provided for each (3 ′) and capable of changing the resistance value from the outside, and the first resistance part (3) and (3 ′) facing the first electrode parts (3) and (3 ′). A second electrode portion (10) provided on a surface different from the surface on which the electrode portions (3) and (3 ') exist, and the first electrode portion (3)
, (3 ') and the second electrode part (10), and is dependent on the voltage between the first electrode part (3), (3') and the second electrode part (10). And a light modulating section (12) whose state of changing the light characteristics is determined, the resistance values of the variable resistance sections (2) and (2 ′) are changed from the outside, and the variable resistance sections (2) and ( A voltage is applied between the first electrode portion (3), (3 ') and the second electrode portion (10) via 2'), and the variable resistance portion (2), (2 ') According to the state of the light modulation section (12) based on the voltage between the first electrode sections (3), (3 ′) and the second electrode section (10) determined according to the resistance value, A spatial light modulator characterized by changing the characteristics of light applied to a modulator (12). 2. The variable resistance part (2) according to claim 1,
(2 ') is composed of a photoconductive film, and the light modulation section (12) is composed of liquid crystal. 3. The transparent electrode according to claim 1 or 2, wherein the second electrode portion (10) is formed integrally with a plurality of the first electrode portions (3) and (3 ′) in common. A spatial light modulator characterized by being provided. 4. The distance between the first electrode parts (3) and (3 ′) and the variable resistance parts (2) and (2 ′) is set to be adjacent to each other according to claim 1, 2, or 3. A spatial light modulator characterized by being formed differently. 5. A writing device for writing information to the spatial light modulator (1) according to any one of claims 1 to 4.
In (20), write light generating means (21) and write control means (23) for performing write control of the spatial light modulator (1)
And the writing light output from the writing light generating means (21) is incident on each of the variable resistance portions (2), (2 '), (2 "), and thereby the spatial light modulator (1) A writing device for a spatial light modulator, which is characterized in that writing is performed on a device. 6. The write light generating means (21) according to claim 5, wherein a plurality of light emitting elements are provided in parallel, and a plurality of write lights are provided in a plurality of variable resistance portions (2), (2 ′), A writing device for a spatial light modulator characterized by being incident on (2 ") at the same time. 7. The writing light scanning means (22) according to claim 5, further comprising a writing light scanning means (22).
Scans the writing light output from the writing light generating means (21) so as to sequentially enter the variable resistance portions (2), (2 ') and (2 "), and the spatial light modulation is performed. A writing device for a spatial light modulator, which writes to the device (1).