JP2000111813A - Optical modulation element and array type optical modulation element as well as plane display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical modulation element which is low in drive voltage, allows an increase in area at a low cost, is easy in manufacture, is simple in constitution and has high image quality and high speed response and an array type optical modulation element as well as a plane display device. SOLUTION: This optical modulation element has a transparent substrate 11 which is transparent to the light to be modulated, a movable grid 14 which has a plurality of slits 13 formed by arraying plural grid plates 12 having light shieldability while parting these plates and has electrical conductivity in at least part thereof, an elastic supporting member which is arranged to face the movable grid 14 apart a prescribed spacing on the transparent substrate 11 and movably supports the movable grid in the arranging direction thereof, light shielding films 19 which are respectively formed in the position of the transparent substrate 11 so as to be superposed on the slit positions of the movable grid 14 and a movable grid moving means which moves the movable grid 14 in the arraying direction of the grid plates 12 by the electrostatic force generated by impressing the prescribed drive voltage to the stationary electrodes arranged on the transparent substrate 11 and the movable grid 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light modulator for performing light modulation by changing the position of a mover by electrostatic force, an array-type light modulator, and a flat panel display.

[0002]

2. Description of the Related Art A light modulation element controls and controls the amplitude (intensity), phase, or traveling direction of incident light to process and display an image or patterned data. The light modulation element changes the refractive index of a substance that transmits light by an external field applied to the substance, and finally transmits or reflects this substance through optical phenomena such as refraction, diffraction, absorption, and scattering. Control the light intensity. As one of the light modulation elements, there is a liquid crystal light modulation element utilizing the electro-optic effect of liquid crystal. This liquid crystal light modulation element is suitably used for a liquid crystal display device which is a thin flat display device.

[0003] A liquid crystal display device encloses and seals a nematic liquid crystal between a substrate on which a pair of conductive transparent films are formed and oriented so as to be parallel to the substrate and twisted by 90 ° between the two substrates. It has a structure in which this is sandwiched between orthogonal polarizing plates. The display by this liquid crystal display device utilizes the fact that by applying a voltage to the conductive transparent film, the long axis direction of the liquid crystal molecules is oriented perpendicular to the substrate and the transmittance of light from the backlight changes. Done. An active matrix liquid crystal panel using a TFT (thin film transistor) is used to provide a good moving image correspondence.

[0004] Plasma display devices include neon, helium,
Between two glass plates filled with a rare gas such as xenon,
It has a structure in which a large number of regularly arranged electrodes in the orthogonal direction corresponding to the discharge electrodes are arranged, and the intersection of each counter electrode is a unit pixel. The display by this plasma display device is based on image information, by selectively applying a voltage to a counter electrode for specifying each intersection, causing the intersection to discharge and emit light, and the generated ultraviolet light to excite the phosphor to emit light. Let it be done.

[0005] The FED has a structure as a flat display tube in which a pair of panels are arranged to face each other with a minute space therebetween, and the periphery of these panels is sealed. A fluorescent film is provided on the inner surface of the panel on the display surface side, and field emission cathodes are arranged on the back panel for each unit light emitting region. A typical field emission cathode has a conical projection field emission type microcathode called a micro-sized emitter tip.
The display by the FED is performed by extracting electrons using an emitter tip and irradiating the electrons with the accelerated phosphor to excite the phosphor.

However, the above-mentioned conventional flat panel display has various problems described below. That is, in the liquid crystal display device, since light from the backlight is transmitted through a plurality of layers of the polarizing plate, the transparent electrode, and the color filter, there is a problem that light use efficiency is reduced. In addition, the high-quality type has a disadvantage that a TFT is required, and liquid crystal must be sealed between two substrates and aligned, which makes it difficult to increase the area. Furthermore, since light is transmitted through the aligned liquid crystal molecules, the viewing angle becomes narrow.

[0007] The plasma display device has disadvantages that the production cost is increased and the weight is increased due to the formation of the partition wall for generating the plasma for each pixel. Further, a large number of electrodes corresponding to the discharge electrodes must be regularly arranged for each unit pixel. For this reason, when the definition becomes high, the discharge efficiency is reduced, and since the luminous efficiency of the phosphor by the excitation of vacuum ultraviolet rays is low, it is difficult to obtain a high-definition, high-brightness image with high power efficiency. Further, there is a disadvantage that the driving voltage is high and the driving IC is expensive.

[0008] In the FED, it is necessary to make the inside of the panel an ultra-high vacuum in order to stabilize the discharge with high efficiency, and there is a drawback that the manufacturing cost becomes high similarly to the plasma display device. In addition, since the field-emitted electrons are accelerated to irradiate the phosphor, a high voltage is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a simple structure which has a low driving voltage, can be inexpensively enlarged, can be easily manufactured, and has high image quality and high-speed response. It is an object to provide a modulation element, an array type light modulation element, and a flat panel display.

[0010]

According to a first aspect of the present invention, there is provided an optical modulator comprising: a transparent substrate transparent to light to be modulated; and a plurality of lattice plates having a light shielding property. With a plurality of slits formed to be arranged while spaced apart, at least a portion of the movable grid having conductivity,
The movable grating is disposed opposite to the transparent substrate at a predetermined interval, and an elastic supporting member that movably supports in the arrangement direction of the grating plate, and at a position of the transparent substrate that overlaps a slit position of the movable grating. The formed light shielding film, the fixed electrode disposed on the transparent substrate and the electrostatic force generated by applying a predetermined drive voltage to the movable grid,
A movable grating moving means for moving the movable grating in the arrangement direction of the grating plates, wherein light modulation is performed by changing the transmittance of light passing through the slit by moving the movable grating.

In this light modulating element, a movable grating formed by arranging a plurality of band-shaped grating plates is supported on a transparent substrate by an elastic supporting member, and the movable grating is moved in the arrangement direction of the grating plates by electrostatic force. Accordingly, the relative positional relationship between the slit of the movable grating and the light-shielding film on the transparent substrate changes, and light modulation can be performed by changing the transmittance of light passing through the slit. That is, when the movable grating is moved to a position where the slit and the light-shielding film on the transparent substrate overlap with each other in the light incident direction, the incident light is emitted from almost the entire area of the slit. On the other hand, when it is moved to a position where it does not overlap, light is blocked by the movable plate and the light-shielding film on the transparent substrate, and the incident light does not pass through the light modulation element.

According to a second aspect of the present invention, in the light modulating device, the movable grating moving means has fixed electrodes disposed on both sides in the moving direction of the movable grating.

In this light modulating element, by disposing the fixed electrodes on both sides in the moving direction of the movable grating, the movable grating can be electrostatically attracted in both the forward and reverse directions. By setting different light transmittances at the neutral position and the reverse movement position,
Light transmittance can be controlled stepwise. In addition, aggressive damping can be performed by instantaneously applying a voltage when the movable lattice returns, which can contribute to high-speed driving of the element.

According to a third aspect of the present invention, in the light modulating element, the fixed electrode side of the movable grating and the movable grating side of the fixed electrode are formed in a comb shape.

In this light modulating element, the amount of displacement of the movable grating is increased by forming the fixed electrode side of the movable grating and the movable grating side of the fixed electrode with respect to the moving direction of the movable grating in a comb shape. And position control by voltage is facilitated. In addition, the degree of freedom of movement in the direction perpendicular to the movement direction is limited by the interval between the comb teeth, so that the movable grating can be moved more accurately and stably.

According to a fourth aspect of the present invention, in the light modulating device, the movable grating moving means is provided so as to sandwich the movable grating between an end of the grating plate and a direction orthogonal to a moving direction of the movable grating. An electrostatic linear actuator is characterized by comprising an electrode formed with a projection projecting toward the movable lattice in accordance with the arrangement pitch.

In this light modulation element, the moving position of the movable grating can be set more accurately and stable by forming an electrostatic linear actuator between the movable grating and the fixed electrode in a direction orthogonal to the moving direction of the movable grating. Can be moved.

The light modulating element according to claim 4, wherein the elastic support member is formed as a pair of support members on the transparent substrate in a moving direction of the movable grating or in a direction orthogonal to the moving direction.
It is characterized by comprising an elastic member connecting the support member and the movable grid.

In this light modulation element, a pair of support members formed in the moving direction of the movable grating or in a direction perpendicular to the moving direction, and an elastic member connecting the support member and the movable grating are easily used as an elastic supporting member. With this configuration, the movable grating can be smoothly moved in the arrangement direction of the grating plates, and a reliable elastic return operation can be obtained by supporting both ends, so that stable light modulation can be performed.

According to a fifth aspect of the present invention, in the light modulation element, the movable grating has a light shielding film formed on a surface of the grating plate.

In this light modulating element, a light shielding film is deposited and formed from above the movable grating while the movable grating is stably supported on the transparent substrate, so that the surface of the movable grating and the transparent substrate corresponding to the slit position of the movable grating are formed. The light-shielding film is formed at the position of, and each light-shielding film can be formed by so-called self-alignment.
Therefore, it is not necessary to accurately position both the movable grating and the transparent substrate, and a light-shielding film can be formed with high positional accuracy by a simple film forming method, thereby reducing the manufacturing cost. Also, good light-shielding properties can be obtained.

According to a sixth aspect of the present invention, there is provided an array type light modulating element, wherein the light modulating elements according to any one of the first to fifth aspects are arranged in a one-dimensional or two-dimensional matrix. And

In this array type light modulation element, one-dimensional or two-dimensional light modulation can be performed by arranging the light modulation elements in a one-dimensional or two-dimensional matrix.

According to a seventh aspect of the present invention, there is provided a flat panel display device comprising: an array type light modulating element according to the sixth aspect; a planar light source disposed to face the array type light modulating element; And a phosphor provided on the opposite side, wherein the phosphor is illuminated and displayed by light transmitted through the array-type light modulation element.

In this flat display device, light emitted from the flat light source is light-modulated by the array-type light modulation element.
Further, the light causes the phosphor to emit light. Therefore, it is possible to obtain a flat display having low driving voltage and high-speed response with a simple configuration.

[0026] In the flat panel display device according to the present invention, the flat light source uses a transparent substrate of the light modulation element as a light guide plate,
Light is introduced from a side end of the transparent substrate.

In this flat display device, since the transparent substrate of the light modulation element is used as a light guide plate, the configuration of the flat display device is simplified, and the size and cost of the flat display device can be reduced.

According to a ninth aspect of the present invention, the light emitted from the flat light source is ultraviolet light.

In this flat panel display, light emission can be displayed by exciting the phosphor.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a light modulator, an array-type light modulator, and a flat panel display according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a plan view showing a configuration of a first embodiment of a light modulation device according to the present invention, and FIG. 2 is an enlarged perspective view of a main part of FIG.

Referring to FIG. 1 and FIG.
0 is a transparent substrate 11 made of a transparent substrate such as a glass plate,
A movable grating 14 that is arranged opposite to the transparent substrate 11 and is arranged in parallel at a predetermined interval to form a slit 13 and also functions as an electrode, and the movable grating 14 is interposed via a beam 15 made of an elastic member. A main part includes a support part 16 supported on the transparent substrate 11 and a fixed electrode 17 for driving the movable grating 14. This movable grating 14
The other end of the beam 15 is fixed to a support 16 disposed on the transparent substrate 11. With this support configuration, the movable grid 14 is supported movably in the X direction, which is the direction in which the grid plates 12 are arranged.

The movable grating 14 is provided on the transparent substrate 11.
A pair of first fixed electrodes 17a and a second fixed
The electrode 17b is arranged. Each fixed electrode 17a, 17b
Is small so as to efficiently increase the electrostatic force in the X direction.
At least the width of the movable grating 14 in the Y direction and the movable grating 14
Formed in a strip-shaped three-dimensional structure with the same height as the conductive part of
Have been. V is applied to the first fixed electrode 17a._s1, Second
V is applied to the fixed electrode 17b. _s2Drive voltage is applied,
V for the child 14 and beam 15_mIs applied. the above
The movable grating 14 and the fixed electrodes 17a and 17b are
It constitutes an eta and corresponds to a movable grid moving means. Ma
The beam 15 and the support portion 16 constitute an elastic support member.
You.

Next, the structures of the transparent substrate 11 and the movable grating 14 will be described in detail. As shown in FIG. 2, the movable grating 14
The lattice plate 12 is a lattice-like member in which a lattice plate 12 is juxtaposed at a predetermined interval in a frame body, and a slit 13 is formed between adjacent lattice plates 12. The movable grating 14 is supported by a beam 15 at a predetermined distance from the transparent substrate 11 so as to be movable in an arrow direction. A light-shielding film 18 is formed on the entire surface of the movable grating 14 so that light introduced from the transparent substrate 11 side can be shielded in a region other than the slit 13. Further, a plurality of light-shielding films 19 are formed in accordance with the position on the transparent substrate 11 that overlaps the position of the slit 13 of the movable grating 14 in the neutral state (stable state), that is, the arrangement interval of the grating plate 12 of the movable grating 14. I have.

The light-shielding film 19 has a width equal to or greater than the slit width 14a of the movable grating 14, and is not formed on the transparent substrate 11 which overlaps with the gap 11a between the adjacent light-shielding films 19. . Therefore, the region where each light-shielding film 19 is formed becomes a light-shielding region of the light modulation element 10, and each light-shielding film 1 is formed.
An area 11a where no 9 is formed becomes a light modulation area where light is transmitted or blocked according to the position of the slit 13 of the movable grating 14.

The light-shielding films 15 and 16 formed on the transparent substrate 11 and the movable grating 14 are formed on the outer surfaces (the upper side in FIG. 2) of the transparent substrate 11 and the movable grating 14 by, for example, a vacuum evaporation method. It can be formed by stacking. That is, a thin film is deposited on the movable grating 14 and the transparent substrate 11 from the Z direction while the movable grating 14 is stopped so as to be in a light-shielding position as shown in FIG.
And a light shielding film is simultaneously formed on the movable grating 14. Thereby, the light shielding film 18 on the movable grid 14 and the transparent substrate 11
Accurate positioning with the upper light-shielding film 19 is not required, so-called self-alignment becomes possible, and the light-shielding films 18 and 19 can be formed with high accuracy by a simple process. Therefore, it is possible to obtain a light modulation element having good light-shielding characteristics while reducing manufacturing costs.

The light shielding films 18 and 19 are preferably made of, for example, a metal film such as aluminum or chromium, or a conductive polymer material, or may be an insulating material such as a carbon dispersed resin. Further, the lattice plate 12 itself may be formed of a light-shielding material.

The first and second fixed electrodes 17a, 17b,
It is preferable that the movable grid 14 has conductivity and is itself a conductor. Specifically, metals, highly doped semiconductors, conductive polymers and the like are mentioned as preferable examples. In addition, the first and second fixed electrodes 17a and 17b and the movable grid 14 may have a configuration in which a conductor is laminated around an insulator. Specifically, a preferable example is a structure in which a metal thin film is deposited around an inorganic insulator such as silicon oxide or silicon nitride, or an insulating polymer such as polyimide. Note that the grid portion of the movable grid 14 does not necessarily need to have conductivity, and only a part of the frame including the fixed electrodes 17a and 17b may have conductivity.

Generally, each of the fixed electrodes 17a and 17b can be made of a conductive metal oxide. As this metal, for example, gold, copper, aluminum, titanium, tungsten, molybdenum, tantalum, chromium, nickel and the like can be used. In addition, as the highly doped semiconductor, crystalline silicon, polycrystalline silicon, amorphous silicon, or the like can be used.

The light modulating element 10 having the above-described structure includes first and second light modulating elements.
The movable grid 14 can be moved in the direction of the arrow shown in FIGS. 1 and 2 by the electrostatic force generated by applying a voltage to the fixed electrodes 17 a and 17 b and the movable grid 14.
Light modulation is performed by the movement of the movable grating 14. That is, as shown in FIG. 3, when the slit 13 of the movable grating 14 is located at a position where the slit 13 overlaps the light-shielding film 19 on the transparent substrate 11, for example, a flat light source (shown in FIG. Light from the light-shielding film 18 and the light-shielding film 19
And is not emitted above the light modulation element 10 (light-shielded state). On the other hand, as shown in FIG.
When the slit 13 is located at a position where it does not overlap with the light-shielding film 19 on the transparent substrate 11, that is, at a position where the lattice plate 12 overlaps with the light-shielding film 19, light emitted from the lower side of the light modulation element 10 is At the position of 19, it is cut off, but the slit 13
Is emitted above the light modulation element 10 (transmission state).

Next, the light modulation element 10 according to this embodiment is
A specific light modulation operation will be described. As shown in FIG. 1A, a state in which a voltage of 0 V is applied to the movable grating 14 and the first and second fixed electrodes 17a and 17b of the light modulation element 10 (V _s1
(= V _s2 = V _m = 0), no electrostatic force acts on the movable grid 14, and the movable grid 14 stops at the light shielding position by the elastic force of the beam 15 (the light shielding state shown in FIG. 3). This light shielding position is in a neutral state. In this case, the light emitted from the flat light source and passing through the light transmitting area on the transparent substrate 11 is transmitted to the light shielding films 18 and 1.
9 is shaded.

As shown in FIG. 1B, when a voltage of 0 V is applied to the first fixed electrode 17a, a voltage of V _on is applied to the second fixed electrode 17b, and a voltage of 0 V is applied to the movable grating 14, (V _s1 =
(V _m = 0, V _s2 = V _on ), the movable grating 14 moves to the second fixed electrode 17b side in the X direction due to the action of static electricity and stops at the position where the light shielding films 18 and 19 overlap (see FIG. 4). Transmission state shown). Thereby, the light emitted from the planar light source and passing through the light transmission area 11 a on the transparent substrate 11 passes through the slit 13 of the movable grating 14 and is emitted above the light modulation element 10. Similarly, V is applied to the first fixed electrode 17a.
_on , by applying a voltage of 0 V to the second fixed electrode 17b and the movable grid 14, the movable grid 14 is moved to the first direction in the -X direction.
It can be moved to the fixed electrode 17a side.

From the state shown in FIG. 1B, the second fixed electrode 1
When the applied voltage to 7b is 0 V, the movable grid 14
Due to the elastic restoring force of No. 5, it returns to the light shielding position which is the initial position. Further, the voltage applied to the second fixed electrode 17a and the movable grid 14 is set to 0 V, and the voltage applied to the first fixed electrode 17a is set to Von instantaneously when returning.
The movable grid 14 can be returned by the combined force of the electrostatic force with the a and the elastic restoring force of the beam 15, so that higher-speed response and higher stable operation can be obtained. Further, although not shown, in the case of electromechanical operation by a drive source in both directions,
A stepwise operation of being transparent when moved in one direction, opaque when moved in the other direction, and translucent when neutral is possible, so that the light transmittance of the element can be set more finely.

As another driving method of the light modulation element 10, _Von and 0V are exchanged with respect to the voltage applied to each fixed electrode and the movable grid in the above-mentioned driving method, and the polarity applied is inverted. It is good. The same operation as described above can be obtained even if the polarity is inverted. In addition, the fixed electrode may be configured to have only one side. In this case, the electrostatic attraction operation is performed in only one direction, so that the configuration and the driving method can be simplified.

As described above, light modulation can be performed by a simple structure in which the movable grating 14 having the plurality of slits 13 formed is moved by electromechanical operation, and the light modulation operation is performed by moving the movable grating 14 by the slit width. Therefore, the amount of displacement of the movable grating 14 can be significantly reduced, and the driving voltage can be reduced. For this reason, the manufacturing process can be facilitated, the cost can be reduced, and an optical modulator having excellent high-speed response and stability can be obtained.

The light modulating elements 10 are arranged one-dimensionally or two-dimensionally on the substrate 11, for example, and driven and controlled by a simple matrix driving method or an active matrix driving method, so that a one-dimensional or two-dimensional array is formed. Can be modulated. The light modulation element 10 is configured to be in a light blocking state in a neutral state, but may be configured to be in a light transmitting state in a neutral state according to a purpose of use.

Next, a second embodiment of the light modulation device according to the present invention will be described. FIG. 5 is a plan view showing the configuration of the light modulation device of the present embodiment. The light modulation element 20 according to the present embodiment includes:
It is the same as the fixed electrode and the movable grating of the first embodiment except that the configuration is different, and the same members are denoted by the same reference numerals and description thereof will be omitted. In the present embodiment, a pair of first fixed electrodes 22a and second fixed electrodes 22b are arranged on the transparent substrate 11 with the movable grid 21 interposed therebetween in the Y direction. The movable grid 21 is used for the beam 15 as in the first embodiment.
The movable grid 21 is configured to be movable in the X direction by being fixed to the support portion 16 on the transparent substrate 11 through the. The fixed electrode side of the movable grid 21 and the movable grid 21 side of the fixed electrodes 22a and 22b are each formed in a comb shape, and are arranged so that the fixed electrode side teeth 22c and the movable grid side teeth 21a alternately mesh with each other. You.

As in the first embodiment, the light modulation operation of the light modulation element 20 is performed by the first and second fixed electrodes 22a and 22b and the movable grating 21 as shown in FIG. When each applied voltage is set to 0 V, the movable grid 21
Is in a neutral state and becomes opaque due to the light shielding effect of the light shielding films 18 and 19.

Then, as shown in FIG. 5B, by setting the voltage V _s2 applied to the second fixed electrode 22b to V _on ,
The comb teeth 21 on the second fixed electrode 22b side of the movable grid 21
An electrostatic attraction acts between the fixed electrode 22b and the comb teeth 22c,
The movable lattice 21 moves in the X direction. Thereby, the light shielding film 1
The light transmittance of the movable grating 21 increases due to the superposition of 8, 19. From this state, the voltage V _s2 applied to the second fixed electrode 22b
Is set to 0V, the state returns to the state shown in FIG. Similarly, when a voltage of V _on is applied to the applied voltage V _s1 to the first fixed electrode 22a, the movable grating 21 moves in the −X direction,
The light transmittance of the movable grating 21 increases.

As described above, by forming the fixed electrode and the movable grating in a comb shape, the amount of displacement of the movable grating can be increased, and the position control by voltage can be facilitated. The movable grids of the first and second embodiments have a configuration in which grid plates are arranged in a frame at predetermined intervals, but a plurality of grid plates are connected at predetermined intervals at the center of the grid plates. The configuration may be as follows. In this case, the rigidity of the entire movable grid is reduced, and it is possible to drive the movable grid at a lower voltage.

Next, an optical modulator according to a third embodiment of the present invention will be described. FIG. 6 is a plan view showing a light blocking state and a light transmitting state in the configuration of the light modulation element of the present embodiment. In the light modulation element 30 of the present embodiment, the movable grating 31 is configured by connecting a plurality of grating plates 32 in parallel on the transparent substrate 11 at predetermined intervals at the center of the grating plate 32.
That is, the shape of the movable grating 31 is changed to the movable grating 14 shown in FIG.
The slits 13 formed at both ends in the longitudinal direction are opened. A light-shielding film is formed on the surface of the lattice plate 32 as in the first and second embodiments, and acts as a slit between adjacent lattice plates 32. Although not shown, a light-shielding film is formed on the transparent substrate corresponding to the slit position in the same manner as in FIG.

On the transparent substrate 11, a pair of the first fixed electrode 33a and the second fixed electrode 3 sandwiching the movable grid 31 in the Y direction.
3b are opposed to each other, and the fixed electrodes 33a, 33b
A plurality of protrusions 33a are formed on the side of the movable lattice 31 in accordance with the arrangement pitch of the lattice plates of the movable lattice 31. As a result, the fixed electrode 33 and the movable grid 31 are formed substantially in a comb shape, and constitute a so-called electrostatic linear actuator. Further, the movable grid 31 is connected to a spring-shaped elastic member 35, and the elastic member 35 is fixed to a support portion 36 provided on the transparent substrate 11. With this support configuration, the movable grid 31 can move in the X direction. The light modulation element 30 according to the present embodiment includes a fixed electrode 33 and a movable grating 31.
The movable element 31 moves in the X direction by the operation of the electrostatic linear actuator accompanying the application of a voltage to the movable element 31. That is, FIG.
When the applied voltage V _m to the applied voltage V _s and a movable grid 31 to the fixed electrode 33 as shown in (a) are both 0V, an electrostatic attraction does not work, the movable grating 31 becomes a neutral state, The element is in a light-shielded state.

[0052] From this state, the applied voltage V _s to V _on to the fixed electrode 33 as shown in FIG. 6 (b), when the applied voltage V _m to the movable grid 31 to 0V, an end portion 32a of the grid plate 32 X by electrostatic attraction to the position where it comes closest to the projection 33a.
And the light-shielding film on the transparent substrate 11 and the lattice plate 32 are superimposed on each other, so that the element is in a light transmitting state.

[0053] Further, when the applied voltage V _s of this state to the fixed electrode 33 and the 0V, there is no electrostatic attraction between the grid plate end 32a and the protrusion 33a, the movable grating 31 is elastic return of the elastic member 19 The operation returns to the original position shown in FIG. Further, in addition to the above control method, for example, the applied voltage V _s of the fixed electrode 33 and 0V, an applied voltage V _m to the movable grid 14 0V, or may be operated by a V _on. Further, the fixed electrodes may be divided into a plurality of groups and offset from each other by オ フ セ ッ ト pitch. Thereby, when the electrode of any group and the edge of the grid plate of the movable grid overlap, a deviation always occurs from any other group, and by sequentially switching the voltage for each group, The movable grating can be moved in either direction. With such an electrostatic linear actuator, the movement of the movable grid 31 can be controlled more accurately and reliably.

Next, a description will be given of a fourth embodiment of the present invention in which a flat display device is constructed using the light modulation elements of the above embodiments. FIG. 7 is a cross-sectional view of a main part of a flat display device 40 configured using the light modulation device of the first embodiment. The flat display device 40 modulates light (for example, ultraviolet light) from a flat light source (not shown) by the light modulation element 10, and emits light to the front plate 41 side through the light modulation element 10, thereby causing the front plate 41 to emit light. This excites the phosphor 42 disposed on the surface on the movable grating 14 side to form a desired image.

The light modulating elements 10 are arranged in a one-dimensional or two-dimensional matrix, and
By arranging the phosphors 42 corresponding to the positions, a desired pattern can be displayed. FIG. 7 shows a configuration in which the light modulation element 10 of the first embodiment is applied as an example. Of course, the light modulation elements 20 and 30 of the second and third embodiments are used.
Can be similarly applied.

The front plate 41 is formed of a transparent substrate such as glass, but may be, for example, a fibrous substrate or a diffusion film. Thus, in addition to the above-mentioned form being applied to a display device, it can also be applied to a contact exposure head for a photosensitive material. The phosphor 42 is disposed in the entire movable grating area of one light modulation element when one pixel is formed of one light modulation element, and is disposed in the case where one pixel is formed of a plurality of light modulation elements. Is
The plurality of light modulation elements are arranged over the entire movable grating.
The black matrix 4 is arranged between the adjacent phosphors 42.
By forming 3, the contrast of the displayed image is improved.

Further, by making the emission color of the phosphor 42 different for each light modulation element, for example, RGB (or YM
C) Color display using three primary colors becomes possible. As described above, the light source may have a configuration in which light is introduced from a side end of the transparent substrate 11 in addition to the configuration in which the planar light source is provided on the transparent substrate 11 on the side opposite to the light modulation element 10 side. In this case, the configuration of the flat display device can be simplified, and the cost can be reduced. By configuring the flat display device in this manner, the light from the light source is directly radiated to the phosphor while taking advantage of the high-speed response and the low-voltage driving characteristics of the light modulation element. Can be obtained, and a flat display device capable of increasing the area at a low cost can be obtained.

[0058]

As described in detail above, the light modulation element of the present invention can perform light modulation by moving the movable grating by a distance between the movable grating and an adjacent grating plate. Therefore, the response speed can be increased, and the driving voltage of the element can be reduced. In addition, since the structure is simple, the manufacturing process is simplified, and the manufacturing cost is reduced. The array-type light modulation element of the present invention can easily perform one-dimensional or two-dimensional light modulation by arranging the light modulation elements in a one-dimensional or two-dimensional matrix, and is lightweight. And an increase in area can be facilitated. Further, the flat display device of the present invention has a high luminance while suppressing a decrease in light use efficiency, since light emitted from the transparent substrate on which the light modulation element is formed is directly irradiated to the phosphor on the front plate. Display can be performed.

[Brief description of the drawings]

FIG. 1 is a plan view showing a light blocking state and a light transmitting state of a light modulation element according to a first embodiment of the present invention.

FIG. 2 is an enlarged perspective view of a main part of the light modulation device of FIG.

FIG. 3 is a sectional view taken along the line AA of the light modulation element of FIG.

FIG. 4 is a sectional view taken along the line AA of FIG. 1 showing a light transmitting state of the light modulation element of FIG. 1;

FIG. 5 is a plan view showing a light blocking state and a light transmitting state of a light modulation element according to a second embodiment of the present invention.

FIG. 6 is a plan view illustrating a light blocking state and a light transmitting state of a light modulation element according to a third embodiment of the present invention.

FIG. 7 is a sectional view illustrating a configuration of a flat panel display device according to a fourth embodiment of the present invention.

[Explanation of symbols]

 10, 20, 30 Light modulating element 11 Transparent substrate 12 Lattice plate 13 Slit 14, 21, 31 Movable lattice 15 Beam (elastic member) 16, 36 Supporting part 17, 22, 33 Fixed electrode 18, 19 Light shielding film 21a, 22c Comb Tooth 42 Phosphor 40 Flat panel display

Claims (10)

[Claims] 1. A movable grating having a transparent substrate transparent to light to be modulated, a plurality of slits formed by arranging a plurality of grid plates having a light shielding property while being spaced apart from each other, and having at least a part having conductivity. An elastic support member for arranging the movable grating opposite to the transparent substrate at a predetermined interval and supporting the movable grating in an arrangement direction of the grating plate; and a position of the transparent substrate overlapping a slit position of the movable grating. The movable grid is moved in the arrangement direction of the grid plate by an electrostatic force generated by applying a predetermined driving voltage to the light shielding film formed on the transparent substrate, the fixed electrode disposed on the transparent substrate, and the movable grid. And a movable grating moving means, wherein light modulation is performed by changing the transmittance of light passing through the slit by moving the movable grating. 2. The light modulation device according to claim 1, wherein said movable grating moving means has fixed electrodes disposed on both sides of the movable grating in the moving direction. 3. The light modulation element according to claim 2, wherein the fixed electrode side of the movable grating and the movable grating side of the fixed electrode are formed in a comb shape. 4. The movable grid moving means is provided so as to sandwich an end of the grid plate and the movable grid in a direction orthogonal to a moving direction of the movable grid, and is movable corresponding to an arrangement pitch of the grid plates. 3. The light modulation element according to claim 2, wherein an electrostatic linear actuator is constituted by an electrode having a protrusion protruding toward the lattice. 5. The elastic support member includes a pair of support members formed on the transparent substrate in a moving direction or a direction orthogonal to the moving direction of the movable lattice, and an elastic member connecting the support member and the movable lattice. The light modulation element according to claim 1, comprising a member. 6. The light modulation device according to claim 1, wherein the movable grating has a light-shielding film formed on a surface of a grating plate. 7. An array-type light modulation element, wherein the light modulation elements according to claim 1 are arranged in a one-dimensional or two-dimensional matrix. 8. An array-type light modulation element according to claim 7, a planar light source disposed to face the array-type light modulation element, and a phosphor provided on the opposite side of the plane light source with the array-type light modulation element interposed therebetween. And a light emitting display of the phosphor by light transmitted through the array type light modulation element. 9. The flat display device according to claim 8, wherein the flat light source uses a transparent substrate of the light modulation element as a light guide plate and introduces light from a side end of the transparent substrate. 10. The flat display device according to claim 8, wherein the light emitted from the light source is ultraviolet light.