JPH04161925A - Space light modulating element and display therefor - Google Patents

Abstract

PURPOSE:To provide a high resolution image having a sufficient brightness by furnishing an information writing part located out of the path of reading light in an information reading part, and installing an addressing means to point the impression part for a light modulating body of the electric field corresponding to the written information. CONSTITUTION:A light modulating body 16 is pinched by electrode base boards 12, 14, and a number of straight transparent electrodes 18 are formed on the base board 12 parallelly in stripes, while on the other base board 14 a number of straight transparent electrodes 24 are formed. Light emitting element arrays 40, 42 are arranged confronting photoelectro-conductive bodies 20, 26 on the base boards 12, 14, and the information writing light is projected on these photoelectro-conductive bodies 20, 26. The reading light from a light source 32 is condensed and projected on a space light modulating element 10, the incident beam penetrates the base board 12 to be cast on the light modulating body 16 and undergoes modulation corresponding to the write image. The reading light after modulation further penetrates the base board 14 and a projector lens 36 to be cast onto a screen 38, Thereby a high resolution display image with good brightness is accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to optical information processing technology, and particularly relates to a spatial light modulation element suitable for parallel processing, display, and storage of moving and still images, and a display device thereof. It is.

[Prior Art] As a conventional spatial light modulator, for example, in 1989,
This was disclosed in the Autumn Proceedings of the Japan Society of Applied Physics Conference, 28p-ZD-5. FIG. 7(A) shows such a conventional technique. In the figure, a transmissive spatial light modulator 100 includes a photoconductor layer 102 made of BSO crystal,
It has a structure in which a light modulator layer 104 made of a liquid crystal composite consisting of a polymer and a nematic liquid crystal is laminated. These are sandwiched between transparent electrodes 106 and 108 made of ITO, and a driving power source 110 is connected between both transparent electrodes.
is connected.

Writing light is incident on such a spatial light modulator 100 from the direction of arrow FA. The BSO crystal constituting the photoconductor layer 102 on which information is written is sensitive only to blue light. Therefore, when writing information, Ar
A laser (λ=488 nm) is used which illuminates the photoconductor layer 102 through a dichroic ink mirror 112 in the desired image pattern. As a result, image information contained in the laser beam is accumulated as a charge image.

Note that this information writing laser light is transmitted to the spatial light modulator 10.
0 is transmitted, but it is cut by the filter 114 and is not output to the screen (see the dotted line in the figure).

Next, the written information is read out using read light incident from the direction of arrow FB.

This readout light is a He-N e laser beam (λ=63
3nrr+) is used, and the dichroic mirror 112
, and enters the spatial light modulator 100 . By the way, an electric field corresponding to the charge image formed on the photoconductor layer 102 by writing the information described above acts on the light modulator layer 104. Therefore, the readout light is modulated by the light modulator layer 104 corresponding to a charge image.

The modulated readout light passes through the filter 114 and is once condensed by the lens 116, and further passes through the aperture 118 and reaches the screen 120, where the readout image is projected (see the dotted chain line in the figure). reference).

As another conventional example, as shown in the same figure (B), 199
Year 05ocity for information
Display (SID90), Digest P2
There are some disclosed in 27-P230.

In the figure, of the light output from the light source 122, R
The (red) light passes through the dichroic ink mirrors 124 and 126 and enters the R light valve 128. Further, the G (green) light passes through the dichroic mirror 124 and is reflected by the dichroic mirror 126 to enter the G light valve 130 . Furthermore, the B (blue) light is transmitted through a two dichroic ink mirror 124. mirror 132
, and enter the B light valve 134.

The light valves 128, 130, and 134 are composed of a d-transistor (TPT) active matrix and a polymer liquid crystal composite, and the TPT active matrix drives the polymer liquid crystal composite, thereby modulating the incident light. It will be done.

The modulated light is transmitted to mirror 136. dichroic ink mirror 1
38 and 140 and the combined light is projected onto the screen 144 by the projection lens unit 142. As a result, images corresponding to the image signals supplied to the light valves 128, 130, and 134 are displayed on the screen 144.

[Problem to be Solved by the Invention 01 However, the above conventional example has the following disadvantages. First, in the conventional technique shown in FIG. 7(A), a BSO crystal is used as a photoconductive means. For this reason, the wavelengths of the information writing light and the m-outgoing light are limited, making it impossible to obtain a read image with sufficient brightness. In addition, the manufacturing process of the spatial light modulator requires highly accurate polishing of the BSO crystal, making it difficult to increase the area and increasing manufacturing costs.

Next, in the conventional example shown in FIG. 3B, since an active matrix using TPT is used, the structure is complicated and the manufacturing cost is high. Another problem is that the smaller the pixels are made to obtain a desired resolution, the lower the brightness of the image becomes. Specifically, the light transmittance of the panel is about 45% with 240×360 pixels.

The present invention has been made in view of the above points, and an object thereof is to provide a spatial light modulation element and a display device thereof that can obtain a high-resolution image with sufficient brightness with a simple configuration. It is something.

[Means for Solving the Problems] The present invention provides a spatial light modulator having an information writing section that writes information to a photoconductor using writing light, and an information reading section that reads information from the light modulator using readout light. The information writing section is provided outside the optical path of the readout light in the information reading section, and the information writing section is provided with an addressing means for instructing a portion to which an electric field corresponding to information written in the information writing section is applied to the light modulator. This is a characteristic feature.

According to another invention, in the display device for reading and displaying information written in the spatial light modulation element, there is provided a writing light irradiation means for writing information in the information writing section, and addressing in the addressing means. The present invention is characterized in that it includes address instruction means for performing the optical modulation, and power supply means for obtaining an electric field to be applied to the light modulator.

[Function] According to the present invention, the information writing section is disposed outside the optical path of the reading light in the information reading section. Therefore, information is read without the read light passing through the information writing section, so a bright image can be obtained.

Further, by making the addressing pitch of the light modulator by the addressing means finer, the resolution of the image is improved.

[Embodiments] Hereinafter, embodiments of the spatial light modulator and its display device according to the present invention will be described with reference to the accompanying drawings.

<First Embodiment> First, a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 shows a spatial light modulation element in the first embodiment, and #2 to #2 in the same figure.
A cross-section along the line is shown in FIG. Further, FIG. 3 shows an exploded state of the spatial light modulation element, and FIG. 4 shows the configuration of a display device.

In these figures, the spatial light modulator 10 has a structure in which a light modulator 16 is sandwiched between electrode substrates 12 and 14. Among these, on the side of the electrode substrate 12 facing the light modulator 16, as shown in FIG. 3, a large number of linear transparent electrodes 18 are formed parallel to each other in stripes at appropriate intervals. A common electrode 22 is formed at one end of each of these transparent electrodes 18 via a photoconductor 20, and the electrodes are formed in a comb shape as a whole.

On the other hand, on the side of the electrode substrate 14 facing the light modulator 16, a large number of linear transparent electrodes 24 are formed parallel to each other in stripes at appropriate intervals. A common electrode 28 is formed at one end of these transparent electrodes 24 via a photoconductor 26, and the electrodes are formed in a comb shape as a whole. Note that the transparent electrodes 18 and 24 do not extend in the same direction, but cross in directions when facing each other. In the illustrated example, the two are orthogonal.

Next, an appropriate drive power source 3o is connected between the common electrodes 22 and 28.
is connected, and the driving voltage due to this is the common electrode 2
2, 28 and photoconductor 20.26, respectively, to each transparent electrode 18.24. That is, when light enters the photoconductor 18.24, that part becomes conductive, and one of the corresponding transparent electrodes 18.24 and the common electrode 22.28 are connected.
This allows the driving voltage to be applied.

Among the above-mentioned parts, the light modulator 16 includes a polymer/liquid crystal composite film 2 whose light transmittance changes depending on the applied voltage, a ferroelectric liquid crystal, STN (Super TwistedN
ematic) LCD, TN (Twisted Ne
matic) liquid crystal etc. are used. Further, as the transparent electrodes 18.24 formed in parallel in large numbers, for example, IT
○(Indium Tin Oxide), Sn
02 etc. are used.

Further, as the photoconductor 20.26, hydrogenated amorphous silicon (a-8i:H) and hydrogenated amorphous silicon carbide (a-8iC:H) are used.

Hydrogenated amorphous silicon germanium (a-8iG
e:H), CdS, Bi12Si○2D crystal material, etc. are used.

A display device using the spatial light modulation element 10 configured as described above is configured as shown in FIG. 4, for example. In the figure, a condenser lens 34 is provided on the readout light side of a suitable light source 32, and the readout light transmitted through this condenser lens 34 is made to enter the spatial light modulation element 1o. Further, a projection lens 36 is provided on the readout light output side of the spatial light modulator 1o, and a screen 38 is arranged on the readout light output side of the projection lens 36.

Furthermore, opposite the photoconductors 20, 26 of the electrode substrate 12.14, a one-dimensional light emitting element array 40 such as an LED array is mounted.
, 42 are arranged, respectively, so that information writing light or scanning light is irradiated onto the photoconductor 20.26.

Next, the operation of the embodiment configured as above will be explained. First, the basic operation of the spatial light modulator 10 will be explained. The image information is the light emitting element array 40, 42
Accordingly, as shown by arrows F10 and F12 in FIG.
The light is incident on photoconductors 20 and 26, respectively. Therefore, the conduction state of the photoconductor 20, 26 changes in response to the -dimensional image information. For example, focusing on the photoconductor 26, the impedance of the photoconductor 26 decreases in accordance with the amount of incident light in the portions where strong light is incident, and the impedance remains high in the portions where no light is incident. That is,
The impedance distribution of the photoconductor 26 changes in accordance with the light intensity distribution of incident light, that is, the image information.

Therefore, in the part where strong light is incident, the linear transparent electrode 24 and the common electrode 28 are in a conductive state with low impedance, and in the part where no light is incident, the transparent electrode 24 and the common electrode 28 remain in a state of high impedance. be. On the other hand, a driving type B30 is connected to the common electrode 28,
This results in a predetermined potential. Therefore, the large number of transparent electrodes 24 can improve the distribution of the amount of incident light on the photoconductor 26.
In other words, the potential distribution corresponds to the incident image information.

Here, it is assumed that a spot of strong light is irradiated onto the other photoconductor 20 so that one of the transparent electrodes 18 and the common electrode 22 are electrically connected. Then, only the potential of the corresponding transparent electrode 18 becomes the potential of the common electrode 22. On the other hand, as described above, the large number of transparent electrodes 18, 24 are formed to cross each other. Therefore, the voltage of the drive power source 30 is applied to the light modulator 16 only at the intersection of the transparent electrode 24, which has a potential distribution corresponding to the incident image, and any of the transparent electrodes 18.

This situation is similar to the scanning of a print head in a printer or the scanning of an electron beam on, for example, a television screen. For example, with respect to the photoconductor 20, the transparent electrode 18
If the light emitting element array 40 irradiates the spot light from the top to the bottom (or vice versa), the light modulator 16 can be scanned in the vertical direction. become. On the other hand, if the photoconductor 26 is irradiated with image information light from the light emitting element array 42 in order from one side of the transparent electrode 24 to the other side, the light modulator 16 can be scanned in the horizontal direction. It turns out.

Note that, conversely, the photoconductor 2o may be irradiated with image information light, and the photoconductor 26 may be irradiated with scanning light.

In this way, electric fields corresponding to image information are sequentially applied to the light modulator 16. Then, in the light modulator 16,
A light modulation state 2 corresponding to the applied electric field at each location, for example, a polarization state of the incident light due to a change in the arrangement of liquid crystal molecules. As a result, one-dimensional image information input to the light emitting element array 40 or 42 is converted into two-dimensional image information, and light modulation corresponding to the image information is performed.

In this state, as shown in FIG.
The readout light output as shown in 14 is condensed by a condenser lens 34 and sent to the spatial light modulator 10 as shown by an arrow F16.
When irradiated, the incident light passes through the electrode substrate 12 and enters the light modulator 16, where it is modulated in accordance with the written image. The readout light after modulation is further transmitted to the electrode substrate 1.
4 through the projection lens 36 as shown by arrows F18 and F20.
The image is then projected onto the screen 38. As a result, the one-dimensional image information input to the light emitting element array 40 or 42 is displayed on the screen 38 as a two-dimensional image.

For example, a case in which image information is displayed at a common video rate, that is, 1730 seconds per frame of playback, will be specifically explained. In this case, the light emitting element array 40 irradiates the photoconductor 20 with light every 1/(30XM) seconds from the upper side of the transparent electrode 18 to the lower side in the figure.

Note that M is the number of transparent electrodes 18.

Then, in synchronization with this, the light emitting element array 42 irradiates the photoconductor 26 with necessary image information light. At this time, the light modulator 16 should be one whose modulation state falls at a rate of about 1/30 second, or in other words, one which maintains the modulation state until the information recording for one frame is completed. is desirable.

As described above, according to this embodiment: (1) Since there is no photoconductor in the readout light passage portion, information can be read out using white light, and an extremely bright display image can be obtained.

(2) By selecting a light modulator, it is possible to handle both analog and digital image information. Further, if a ferroelectric liquid crystal is used as the light modulating material, written information can be stored, so it is possible to provide a memory function such as storing and displaying image information for one frame.

(3) Since a complicated matrix structure is not required, the manufacturing method is simple, the process can be simplified, and it is advantageous in terms of cost.

(4) Since the size of the pixel is determined only by the pitch of the transparent electrodes, high-resolution image display and storage are possible.

(5) Unlike conventional active matrix or simple matrix type display devices, addressing can be performed using optical signals.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIG. Note that the same reference numerals are used for components similar to or corresponding to those of the above-described embodiments (the same applies to the following embodiments).

In this embodiment, as shown in the figure, the transparent electrode 18.2
4 is a side surface 50A of the electrode substrates 50 and 52.

It has been extended to 52A. And this side 50A,
52A, photoconductors 20, 26 . common pole 22.28
are formed respectively.

According to this embodiment, the input/output direction of the readout light is indicated by the arrow F1.
6. F18, which is the same as the previous embodiment, but the direction of incidence of the information writing light and scanning light is indicated by the arrow F22. F24, which is a direction perpendicular to that of the above embodiment. Note that other points are the same as in the embodiment described above.

Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIG. In this embodiment, as shown in the figure, writing light is irradiated onto the photoconductors 20 and 26 using a point light source 60.62 for writing light output and a polygon mirror 64.6.
This is done in combination with 6.

The writing lights output from the point light sources 60.62 are reflected by the rotating polygon mirrors 64, 66, respectively, and are reflected by the arrows F26. Photoconductor 20°26 as shown respectively at F28
The upper surface is scanned in the direction in which the transparent electrodes 18 and 24 are arranged. The other parts are the same as those in the first embodiment described above.

It should be noted that the present invention is not limited to the above-mentioned embodiment in any way; for example, the shape and dimensions of each part may be changed as necessary. For example, in the embodiment, the transparent electrode 18
．． 24 are arranged orthogonally, but they do not need to be orthogonal if they are arranged crosswise. Furthermore, although the spatial light modulator is constructed as a transmissive type, the same effect can be obtained even if it is constructed as a reflective type by providing a mirror means on one of the electrode substrates.

Further, in the above embodiment, both of the transparent electrodes 18 and 24 are driven through the photoconductor, but the one for writing image information is driven by the photoconductor, and the scanning drive of the other is performed by a transistor, etc. It may also be done in a circuit manner using .

Alternatively, the photoconductor may be formed separately for each transparent electrode. In particular, when the number of transparent electrodes is increased to increase image resolution, crosstalk may occur in the photoconductor. In such a case, each transparent electrode is separated to form a photoconductor.

Furthermore, by using a color filter in the readout light irradiation portion of the spatial light modulation element, color image display is also possible, and these are also included in the present invention.

[Effects of the Invention] As explained above, according to the spatial light modulator and display device thereof according to the present invention, the information writing section centered on the photoconductor can be read by the information reading section centered on the light modulator. Since it is provided outside the optical path of the light, the readout light contributes to information readout without passing through the photoconductor. Therefore, an extremely bright image can be obtained. Further, the resolution of the image can be easily improved by making the address pitch in the address means finer.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of a spatial light modulation element according to the present invention, FIG. 2 is a cross-sectional view of the element in FIG. 1 taken along the line #2-#2, and FIG. FIG. 4 is an explanatory diagram showing a first embodiment of the display device; FIG. 5 is a partially broken configuration diagram showing a second embodiment of the present invention; FIG. 6 is a configuration diagram showing a third embodiment of the present invention, and FIG. 7 is an explanatory diagram showing a conventional technique. 10-... Spatial light modulation element, 12, 14, 50.52.
... Electrode substrate, 16... Light modulator, 18.24...
Transparent electrode (address means), 20.26... Photoconductor, 22.28... Common electrode, 3o... Drive power source (power source means), 32... Power source for reading, 40... Light emission Element array (address indicating means), 42... Light emitting element array (writing light irradiation means), 50A, 52A... Substrate side surface, 60, 62... Point light source, 64.66... Polygon mirror. Patent applicant: Victor Japan Co., Ltd.

Claims (2)

[Claims] (1) A spatial light modulator having an information writing section that writes information to a photoconductor using writing light, and an information reading section that reads information from the light modulator using reading light, wherein the information writing section is Spatial light modulation characterized by comprising an address means provided outside the optical path of the readout light in the information reading section and for instructing the application site of the electric field corresponding to the information written in the information writing section to the light modulator. element. (2) A display device for reading and displaying information written in the spatial light modulator according to claim 1, further comprising a writing light irradiation means for writing information in the information writing section and addressing in the addressing means. 1. A display device comprising: address instruction means for controlling the light modulator; and power supply means for obtaining an electric field applied to the light modulator.