JP2000131627A - Optical modulation element and array type optical modulation element as well as plane display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve light utilization efficiency, to eliminate the need for a higher vacuum, to enable a larger area at a low cost, to make it possible to obtain higher image quality and to lower driving voltage. SOLUTION: The optical modulation element 20 displaces respective moving elements 15 to the prescribed extent in approximately parallel with a transparent substrate 1 between adjacent grid walls 5 by the effect of static electricity accompanying the voltage impression to the plural grid walls 5 which are pairing electrodes and the moving elements 15, thereby changing the relative positions of the respective moving elements 15 with respect to the optical modulation area 13 of the transparent substrate 1. As a result, the optical modulation element 20 executes the light modulation of the light introduced to the transparent substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light modulation element for performing light modulation by changing the position of a mover by electrostatic stress, an array type light modulation element, and a flat display device using the same.

[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.

[0006]

However, the above-described conventional flat panel display has the following various problems. That is, in the liquid crystal display device, light from the backlight is transmitted through a plurality of layers of the polarizing plate, the transparent electrode, and the color filter, so that there is a problem that the light use efficiency is reduced. In addition, a TFT is required for a high-quality type, and a liquid crystal must be injected between two substrates to be aligned, which makes it difficult to increase the area. Furthermore, since light is transmitted through the aligned liquid crystal molecules, there is a disadvantage that 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. Furthermore, the driving voltage is high and the driving IC
However, there were disadvantages that were 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, has a good light utilization efficiency, does not require a high vacuum, can have a large area at a low cost, and has a high image quality. It is an object of the present invention to provide a light modulation element having a low driving voltage, an array type light modulation element, and a flat display device using the same.

[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; Fixed wall having a property, a light-shielding film laid out leaving an opening serving as a light modulation region outside the standing region of the fixed wall on the transparent substrate, and supported movably in a substantially horizontal direction on the opening. By applying a voltage between the movable element having light-shielding properties and conductivity, and the fixed wall and the movable element, the movable element is moved by electrostatic force, and the light-shielding area covering the opening is changed. Mover moving means for moving the mover to change the transmittance of light passing through the light modulation region to perform light modulation.

In this light modulation element, each movable element is displaced substantially in parallel with the transparent substrate by the action of static electricity, and the relative position of each movable element with respect to the light transmitting area and the light shielding area of the transparent substrate is changed. This modulates light incident on the transparent substrate. That is, by moving each mover to a position overlapping the light modulation region of the transparent substrate, light introduced into the transparent substrate is shielded, while each mover is moved to a position overlapping the light shielding film on the transparent substrate. Thereby, the light introduced into the transparent substrate can be emitted above the light modulation element.

According to a second aspect of the present invention, in the light modulation element, the fixed wall is
A plurality of the light-shielding films and the movers are respectively provided substantially in parallel at predetermined intervals and provided between the lattice walls.

In this light modulating element, a plurality of fixed walls are erected substantially in parallel at a predetermined interval, and a light-shielding film and a movable element are provided between each lattice wall, so that a plurality of light modulating regions are provided. Can change the light transmittance.
In addition, since the displacement of the mover can be reduced and the mover can be reduced in size and weight, high-speed light modulation at a low voltage can be stably performed.

According to a third aspect of the present invention, in the light modulating element,
Laid between adjacent grid walls so as to form an opening on the side of the other grid wall in contact with the side of one grid wall;
The movable element is provided on the side of the other lattice wall so as to cover the opening.

In this light modulation element, a light-shielding film is laid between adjacent lattice walls so as to be in contact with one lattice wall and to form an opening on the other lattice wall. By providing the movable element on the side of the other lattice wall so as to cover the opening, the transparent substrate, the lattice wall, and the light-shielding region of the movable element can be simultaneously formed by self-alignment.

According to a fourth aspect of the present invention, in the light modulation element, the fixed wall is
It has a light shielding property.

In this light modulation device, since the fixed wall has a light-shielding property, light introduced to the transparent substrate which does not contribute to light modulation can be reliably shielded, and the light modulation ability is improved. Can be.

According to a fifth aspect of the present invention, in the light modulating element, the movable element may include:
It is characterized by comprising a conductive portion and a light shielding portion formed substantially perpendicular to the transparent substrate.

In this light modulating element, the conductive portion and the light shielding portion of the mover are formed substantially perpendicular to the transparent substrate, so that the efficiency of generating the electrostatic force by the conductive portion is improved, and the mover is more stably formed. Be able to move.

According to a sixth aspect of the present invention, in the light modulating element,
It is characterized by comprising a conductive portion formed substantially perpendicular to the transparent substrate and a light shielding portion formed substantially horizontal to the transparent substrate.

In this light modulation device, the conductive portion of the mover is formed substantially perpendicular to the transparent substrate, and the light shielding portion is formed substantially horizontal to the transparent substrate, so that the efficiency of generating electrostatic force by the conductive portion is improved. At the same time, the light-shielding efficiency of the light-shielding portion is enhanced, and good light-shielding properties can be obtained with a minimum necessary film thickness.

According to a seventh aspect of the present invention, in the light modulating element, the movable element moving means makes the potential between the movable element and the fixed wall coincide when the movable elements are not operated, while the movable element moves when the movable elements are operated. Different potentials are applied between the fixed wall on the moving direction side of the child and the mover.

In this light modulating element, when each movable element is not operated, since the potential between the movable element and the fixed wall coincides, the movable element stops at the neutral position without the action of electrostatic force.
Further, during the operation of each mover, the potential between the mover and the fixed wall becomes different, and the mover moves toward the fixed wall due to the generated electrostatic attraction. By this movement, light modulation is performed accurately and stably.

In a preferred embodiment, the movable element moving means connects one fixed wall adjacent to the movable element to an image signal electrode, and connects the other fixed wall to a scanning signal electrode. The movable element is connected to the same electrode as the fixed wall on the adjacent side.

In this light modulating element, by connecting the fixed walls alternately to the image signal electrodes and the scanning signal electrodes, the movable elements are attracted and moved by the fixed walls having different polarities during the operation of the movable elements. The light is modulated.

According to a ninth aspect of the present invention, in the light modulating device, the mover moving means connects one of the scanning signal electrode and the image signal electrode to the fixed wall, and connects the other electrode to the mover. It is characterized by connecting.

In this light modulating element, all of the movable element is connected to one of the scanning signal electrode and the image signal electrode, and all of the lattice walls are connected to the other electrode. Simplified.

According to a tenth 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 ninth aspects are arranged in a one-dimensional or two-dimensional matrix. It is characterized by having done.

In this array type light modulating element, the light modulating elements arranged in a one-dimensional or two-dimensional matrix are selectively driven based on the image information, so that the display processing of the image information becomes possible.

[0030] According to a eleventh aspect of the present invention, there is provided a flat panel display device comprising: an array-type light modulation element according to the tenth aspect; a plane light source disposed to face the array-type light modulation element; And a phosphor provided on the opposite side of the flat light source, wherein the phosphor emits and displays light by light transmitted through the array-type light modulation element.

In this flat display device, when the mover overlaps the light-shielding film on the transparent substrate by the electromechanical operation, the light introduced into the transparent substrate passes through the light modulation region and is emitted above the light modulation element, The emitted light excites the phosphor to enable display of an image based on image information.

[0032] In a twelfth aspect of the present invention, the flat light source is characterized in that the transparent substrate of the light modulation element is a light guide plate and light from the light source is introduced into 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 device can be reduced.

According to a thirteenth 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.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a light modulation element, an array type light modulation element 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 perspective view in which a part of the light modulation element according to the present invention is cut away, FIG. 2 is a plan view of an array-type light modulation element in which the light modulation elements shown in FIG. 1 are arranged in a simple matrix configuration, and FIG. 1 is a plan view of an array-type light modulation element in which the light modulation elements shown in FIG.

As shown in FIG. 1, a plurality of light shielding films 3 are formed at regular intervals on a transparent substrate 1 having an insulating property and being transparent to light to be modulated. The light-shielding film 3 blocks light from below the transparent substrate and prevents light from being emitted upward. On the transparent substrate 1, a lattice wall 5 is provided between the adjacent light shielding films 3 so as to be in contact with one of the light shielding films 3. A strip-shaped conductor (charger) 8 is formed inside the lattice wall 5, and the surface of the conductor 8 is covered with an insulator 9. The light-shielding film 11 is formed on the upper end surface of the lattice wall 5. Therefore, the light introduced from below the transparent substrate 1 is transmitted to the lattice wall 5 in the state shown in FIG.
Is not emitted from the upper end face of the. When this grating wall 5 is used as a light modulation element and a display device, it can be used as a black matrix for improving a contrast ratio.

A light modulation region 13 is formed between the grating wall 5 and the other light shielding film 3 not in contact with the grating wall 5. Light introduced from below the transparent substrate 1 is transmitted through the light modulation region 13.
And is emitted to the upper side of the transparent substrate 1. A mover 15 is provided above the light modulation area 13. Mover 1
5 has a constricted portion 15a having a reduced cross-sectional area at both ends in the longitudinal direction. The constricted portion 15a becomes a fragile portion and is deformed, so that the movable element 15 is parallel to the transparent substrate 1. It can be moved in any direction. The movable element 15 has a strip-shaped conductor (charger) 18 and a light-shielding film 19 formed on the upper surface of the conductor 18. The conductor 18 and the light-shielding film 19 may be integrally formed of a light-shielding conductive film. For example, the mover 15 can be made of a metal, a metal compound, a highly-doped semiconductor, a conductive polymer, or the like, and may impart a light-shielding property to itself. Further, a conductive film may be formed around the insulator (particularly, the side surface of the mover). When the movable element 15 is in the neutral state (when the conductors have the same potential and no electrostatic force acts), the movable element 15 is disposed on the light modulation area 13 and the light modulation area 1
3 is prevented from being emitted to the upper side of the light modulation element 20.

The light modulation device 20 thus configured is
A two-dimensional array type light modulation device 23 shown as an example in FIG.
Can be formed. The array type light modulation element 23
The plurality of scanning signal electrodes 25 are arranged in parallel, and the plurality of image signal electrodes 29 are arranged in parallel at right angles to the scanning signal electrodes 25. Of course, the present invention is not limited to this example, and may be an array-type light modulation element in which light modulation elements are arranged one-dimensionally.
The scanning signal electrode 25, the image signal electrode 29, and a control device (not shown) for controlling signals output to them correspond to the mover moving means. Here, FIG. 2 is a configuration diagram of a simple matrix, but as shown in FIG. 3, an active matrix in which a semiconductor switch 28 such as a TFT is provided for each pixel, or a flexible thin film having a contact portion (not shown). An active matrix configuration in which an electromechanical switch operated by the static electricity operation is provided for each pixel may be used. The light modulation element shown in FIG. 1 can be formed by various thin-film processes or thick-film processes such as patterning, etching, plating, printing, and transfer by photolithography.

Next, the pixel section in the simple matrix configuration will be described. The light modulation element 20 includes the scanning signal electrode 2
5 and the image signal electrode 29 are provided at the intersections.
As shown in FIG. 4 (a), each of these light modulating elements 20
One of the two grid walls 5 adjacent to one mover 15 is connected to the image signal electrode, and the other grid wall is connected to the scanning signal electrode. The mover is connected to the same electrode as the lattice wall on the adjacent side. That is, the movable element 15 and the light shielding film 3 sandwiched between the two lattice walls 5 each form one light modulation section. With such an element configuration and electrode connection, when the voltage of the image signal electrode 29 with respect to the scanning signal electrode 25 is 0 [V], as shown in FIG. In the case of Va [V], as shown in FIG. 4B, the mover moves by the electrostatic force and enters the light transmitting state.

Next, the light modulating element 2 thus constructed
0 and a specific driving method of the array type light modulation element 23 will be described. As shown in FIG. 5A, the scanning signal electrode 25,
When the image signal electrodes 29 have the same potential (0 [V]),
The mover 15 is positioned above the light modulation region 13 so as to overlap with each other.
The light that has passed through the light modulation region 13 is prevented from being emitted to the upper side of the light modulation element 20.

On the other hand, as shown in FIG. 5B, when an image signal voltage Va is applied to the image signal electrode 29 and a voltage of 0 [V] is applied to the scanning signal electrode 25 during scanning, the image is not displayed. The movable element 15 is attracted to the lattice wall 5 by electrostatic attraction between charges stored in the signal electrode 29 and the conductor 8 of the lattice wall 5 and between the charges stored in the scanning signal electrode 25 and the conductor 18 of the movable element 15. Then, as shown by the arrow in the figure, the light source moves in parallel with the transparent substrate 1. As a result, light is not blocked by the mover 15 in the light modulation region 13, and the light that has passed through the transparent substrate 1 is emitted from the light modulation region 13, thereby enabling binary light modulation. According to this basic principle, a two-dimensional light modulation array can be driven by the simple matrix structure shown in FIG. In this example, the scanning signal electrode 25 and the image signal electrode 29
This is performed by applying an appropriate voltage to both the electrodes 25 and 29 in accordance with the hysteresis characteristic of the relationship between the voltage of the movable member 15 and the displacement of the mover 15 due to the characteristic.

In the first embodiment, the neutral position where the applied voltage is all 0 [V] is set to the light shielding position shown in FIG. 4A, and the light shielding position shown in FIG. (b)
Assuming binary control with the light transmission position shown in FIG.
The lattice wall 5 and the light shielding area of the mover 15 can be formed simultaneously by self-alignment.

That is, in a state where the movable element 15 is located at the light shielding position with respect to the transparent substrate 1 (the state shown in FIG. 4A), the movable element 15 and the transparent substrate 1 By vapor-depositing the like, the light-shielding region of the transparent substrate 1, the lattice wall 5, and the movable element 15 can be formed at the same time. This eliminates the need for alignment of the light-shielding film 19 on the mover 15 with the light-shielding film 3 on the transparent substrate 1 and the light-shielding film 11 on the lattice wall 5 (self-alignment), and keeps the manufacturing process high in forming accuracy. While the manufacturing cost can be reduced. Further, a light-shielding film with extremely little leakage light can be obtained. In addition to the above example, the arrangement of the lattice wall 5, the mover 15, and the light-shielding film 3 may be any arrangement. In addition, the connection method of each electrode and the applied voltage may be any combination as long as it is in accordance with the gist of the present invention. For example,
As shown in FIG. 6A as a modified example of this embodiment, the light shielding films 3 are alternately laid on the grid wall 5 at a position in contact with the right side and a position in contact with the left side, and the neutral position is adjusted accordingly. Position of the mover 15 in the light modulation region 1
3 may be arranged so as to be overlapped above. According to this arrangement, all of the movers are connected to the image signal electrodes, and only the lattice walls are connected to the scanning signal electrodes. Therefore, the wiring structure and the formation process thereof are simplified.

Further, as shown in FIG. 7, a structure in which the grid wall on the mover side in the neutral state in FIG. In this configuration, every other lattice wall can be omitted, and the wiring structure and the formation process thereof are further simplified. FIG. 7 shows an example in which the mover is connected to the image signal electrode and the lattice wall is connected to the scan signal electrode. However, the mover is connected to the scan signal electrode, and the lattice wall is connected to the image signal electrode. A configuration may be adopted, and in this case, a similar operation is obtained.

The light modulation elements having the above-described configurations can be arranged at a high density on a transparent substrate, and a high resolution can be easily obtained. By forming one pixel in a lattice shape, the amount of displacement of the mover required for modulation can be reduced, and the mover can also be reduced in size and weight. Therefore, it is possible to stably perform high-speed light modulation at a low voltage. Further, when the light modulation element of the present embodiment is driven by an active matrix configuration as shown in FIG. 3, for example, 0 [V] is applied using the scanning signal electrode of the previous example as a common electrode, and a pixel switch is applied to the image signal electrode. Through a desired voltage (for example, 0 [V]
To Va [V]). In this case, a higher contrast ratio can be obtained, and continuous gradation can be obtained by appropriately setting the value of the applied voltage, the application time, and the like. In the present embodiment, a configuration in which one pixel includes six light modulation regions is shown. However, the present invention is not limited to this, and a configuration in which an arbitrary plurality of light modulation regions are provided may be employed. Further, the light-shielding film 3 on the transparent substrate 1 is laid on another transparent substrate provided separately from the light modulation element 20, and the other transparent substrate and the transparent substrate 1
May be joined while positioning them. With this configuration, the manufacturing process of the light modulation element 20 is simplified.

Next, a second embodiment of the light modulation device according to the present invention will be described. FIG. 8 is a cross-sectional view of a main part showing a light shielding state and a transmission state of the light modulation element according to the present embodiment. The light modulation element 30 of the present embodiment has a configuration in which a conductor 18a is provided vertically at the end of each movable element 16 opposite to the lattice wall 5. By reducing the thickness of the conductor 18a in this manner, the weight of each mover 16 can be reduced, so that the moving operation of the mover 16 at the time of performing optical modulation has good high-speed response. Can be. Further, by setting the neutral position where the applied voltages are all 0 [V] to the light shielding position shown in FIG. 8A, binary light modulation is enabled.

As shown in FIG. 8A, each of these light modulation elements 20 connects one of the two lattice walls 5 adjacent to one mover 16 to the image signal electrode, and , The other lattice wall is connected to the scanning signal electrode. The mover is connected to the same electrode as the lattice wall on the adjacent side. That is, the movable element 15 and the light shielding film 3 sandwiched between the two lattice walls 5 each form one light modulation section.

The light modulation operation by the light modulation element 30 will be described below. As shown in FIG. 8A, the voltages of the conductors 8 and 18a of each lattice wall 5 and each movable element 16 are both 0 [V].
In the neutral state where
It stops above the light modulation area 13 by the elastic force of the constricted part 15a. As a result, light introduced from below the transparent substrate 1 passes through the light modulation region 13 but is shielded by the light shielding film 19 of the movable element 16 (light shielding state).

On the other hand, as shown in FIG.
When a predetermined drive voltage Va and a voltage 0 [V] are alternately applied to the conductors 8 and 18a of the movers 16, respectively,
Each mover 16 is attracted and moved toward the adjacent lattice wall 5 by the action of electrostatic force, and opens above the light modulation region 13. Accordingly, light introduced from below the transparent substrate 1 passes through the light modulation region 13 and is emitted above the light modulation element 40 (light transmission state). Then, the voltage applied to the conductors 8 and 18a of each lattice wall 5 and each mover 16 is again reduced to 0.
When [V] is set, each mover 15 returns to the neutral position shown in FIG. 8A by the elastic force of the constricted portion 15a.

In the present embodiment, as shown in FIG. 9, the positions of the conductors of each lattice wall 5 and each movable element 16 are unbalanced so that the voltage is applied to the conductors 8 of each lattice wall 5. The voltage may be all 0 [V] and the voltage applied to the conductor 18a of each mover 16 may be all Va. In this case, the wiring process is simplified, and the distance between the grid wall 5 and the conductors of the mover 16 is shorter, so that high-speed response is possible with low-voltage driving.

Next, a description will be given of a third embodiment in which a flat panel display device is formed by using the above-described light modulation element. FIG. 10 shows a cross-sectional view of the flat display device 40 according to the present invention. As the light modulation element of the present embodiment, the light modulation element 20 of the first embodiment is used.
Is used as an example. Flat display device 4 of the present embodiment
In the configuration of No. 0, an ultraviolet flat light source 31 serving as an ultraviolet output unit is provided on the lower surface of the transparent substrate 1 of the light modulation element 20.
A front plate 35 is provided above the light modulation element 20, and the fluorescent substance 3 is provided on a surface of the front plate 35 on the light modulation element 20 side.
3a, 33b,... Are provided for each light modulation element 20.
In addition, a black matrix 34 is provided between the respective phosphors to improve the contrast of a displayed image. With such a configuration of the flat panel display device 40, light from the flat light source 31 enters the transparent substrate 1 and is guided to the upper surface of the transparent substrate 1 in FIG. When the light from the light modulation element 20 is applied to the phosphor, the phosphor is excited and emits light, whereby a desired image is formed. As the phosphor, three primary colors (for example, R,
G and B) phosphors may be sequentially provided so that a color image can be displayed, or a monochrome image display may be formed by using only a single color phosphor.

The light modulation element 20 of the flat panel display 40
After degassing the space between the transparent substrate 1 and the front plate 35, a rare gas may be sealed to seal the whole, preventing the influence of disturbance and stabilizing. Further, the light modulation element 30 in the second embodiment can be similarly applied to the flat display device 40.

Next, the operation of the flat display device 40 having the above-described configuration will be described. When the scanning signal electrode 25 and the image signal electrode 29 have the same potential, the mover 15
, The light from the planar light source 31 is blocked by the mover 15 and the light-shielding conductive film 3, and
Is not transmitted to the upper surface side of.

At the time of scanning, when a sufficient voltage is applied between the image signal electrode 29 and the scanning signal electrode 25, each movable element 15 in one pixel area moves toward the lattice wall 5 by electrostatic attraction. Move all at once. As a result, light is not blocked by the mover 15, and light passing through the transparent substrate 1 is transmitted to the light modulation region 1.
3 is emitted. The emitted light is emitted from the phosphors 33a, 33
b is excited to display an image based on the image information.

When this light modulation element is controlled by two values,
A full-color display is possible by a driving method in which a field cycle for displaying one screen is divided into a plurality of subfields, and binary control is performed independently in each subfield to obtain multiple gradations. Further, according to the active matrix driving method, light modulation of various continuous gradations is possible, and full color display is possible.

As described above, according to the flat display device 50 described above, the light emitted from the transparent substrate 1 is directly transmitted to the phosphor 33.
Since the light is excited by irradiating a and 33b, the light use efficiency can be improved. Further, since the phosphor emits scattered light, the viewing angle can be widened as compared with a liquid crystal display device which transmits light by the alignment of liquid crystal molecules. Further, since the arraying is easy, the manufacturing cost can be reduced.
Then, by using a low elasticity material, for example, a polymer such as polyimide as the material of the mover 15 or optimizing the shape, the driving voltage can be sufficiently reduced as compared with a plasma display device or the like.

[0058]

As described above in detail, according to the light modulation element of the present invention, each movable element is displaced substantially in parallel to the transparent substrate by the action of static electricity, and the light modulation area on the transparent substrate is displaced. The light introduced into the transparent substrate is modulated by changing the relative position with respect to. Therefore, the driving voltage can be kept low at low cost, the required displacement of the mover required for optical modulation can be reduced, and excellent high-speed response can be ensured. In addition, by minimizing the size of the conductor to the minimum necessary, the mover is reduced in weight,
Faster responsiveness can be obtained.

The array-type light modulation device according to the present invention can easily perform one-dimensional or two-dimensional light modulation by arranging the light modulation devices in a one-dimensional or two-dimensional matrix. Can be. Further, partition formation for generating plasma for each pixel as in a plasma display, and FE
Since the ultra-high vacuum is not required as in D, the weight and the area can be easily increased, and the manufacturing cost can be reduced.

In the flat panel display device according to the present invention, since the light emitted from the transparent substrate directly excites the phosphor, the display device has high luminance and has no viewing angle dependence while suppressing a reduction in light use efficiency. Display can be performed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a light modulation element according to the present invention.

FIG. 2 is a plan view of an array-type light modulation element in which the light modulation elements of FIG. 1 are arranged in a simple matrix configuration.

FIG. 3 is a plan view of an array-type light modulation element in which the light modulation elements of FIG. 1 are arranged in an active matrix configuration.

FIG. 4 is a connection diagram showing a connection state between a scanning signal line and an image signal line of the light modulation element.

FIG. 5 is a cross-sectional view of a principal part explaining each operation state of the light modulation element of the first embodiment.

FIG. 6 is a sectional view of a main part showing a modification of the light modulation element of the first embodiment.

FIG. 7 is a cross-sectional view of a main part showing another modified example of the light modulation element of the first embodiment.

FIG. 8 is a cross-sectional view of a principal part explaining each operation state of the light modulation element of the second embodiment.

FIG. 9 is a sectional view of a main part showing a modification of the light modulation element of the second embodiment.

FIG. 10 is a cross-sectional view of a main part showing a configuration of a flat panel display device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transparent substrate 3 light-shielding conductive film 5 lattice wall 8, 18, 18 a conductor 13 light modulation area 15, 16 mover 20, 30 light modulation element 23 array type light modulation element 25 scanning signal electrode 29 image signal electrode 31 ultraviolet plane Light source 33a, 33b phosphor 40 flat panel display

Claims (13)

[Claims] 1. A transparent substrate transparent to light to be modulated, a fixed wall standing on the transparent substrate and having conductivity, and a light modulation region outside a standing region of the fixed wall on the transparent substrate. A light-shielding film laid leaving an opening, and a movable element having a light-shielding property and conductivity supported movably in a substantially horizontal direction on the opening, between the fixed wall and the movable element. Moving the movable element by an electrostatic force by applying a voltage, and a movable element moving means for changing a light shielding area covering the opening, and a light passing through the light modulation region by the movement of the movable element. A light modulation element for performing light modulation by changing transmittance. 2. The fixing wall according to claim 1, wherein a plurality of the fixed walls are erected substantially in parallel at predetermined intervals, and the light-shielding film and the mover are provided between each lattice wall. Light modulation element. 3. The light-shielding film is laid between adjacent lattice walls so as to contact one lattice wall side and form an opening on the other lattice wall side, and the mover includes 3. The light modulation element according to claim 2, wherein the light modulation element is provided on the side of the other lattice wall so as to cover the opening. 4. The light modulation device according to claim 1, wherein the fixed wall has a light shielding property. 5. The light according to claim 1, wherein the mover comprises a conductive portion and a light shielding portion formed substantially perpendicular to the transparent substrate. Modulation element. 6. The movable element comprises a conductive portion formed substantially perpendicular to the transparent substrate, and a light-shielding portion formed substantially horizontal to the transparent substrate. The light modulation device according to claim 1. 7. The mover moving means makes the electric potential between the mover and the fixed wall coincide when each mover is not operated, and fixes the electric potential on the moving direction side of each mover when each mover is operated. The light modulation element according to claim 1, wherein different electric potentials are applied between a wall and the mover. 8. The mover moving means connects one fixed wall adjacent to the mover to an image signal electrode,
8. The light modulation device according to claim 7, wherein the other fixed wall is connected to a scanning signal electrode, and the mover is connected to the same electrode as the fixed wall on the adjacent side. 9. The mover moving means connects one of the scanning signal electrode and the image signal electrode to the fixed wall, and connects the other electrode to the mover. The light modulation device according to claim 7. 10. An array type light modulating element, wherein the light modulating elements according to claim 1 are arranged in a one-dimensional or two-dimensional matrix. 11. An array-type light modulation device according to claim 10, a planar light source arranged to face the array-type light modulation device, and a phosphor provided on the opposite side of the plane light source with the array-type light modulation device interposed therebetween. And a light emitting display of the phosphor by light transmitted through the array type light modulation element. 12. The flat display according to claim 11, wherein the flat light source is formed by using a transparent substrate of the light modulation element as a light guide plate and introducing light from the light source into the transparent substrate. apparatus. 13. The flat display device according to claim 11, wherein the light emitted from the light source is ultraviolet light.