JP2003315694A - Image display element and image display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display element which can be reduced in thickness with an inexpensive and simple structure and an image display device using the same thereby reducing the cost and size over the entire part of the image display device. <P>SOLUTION: The image display device is equipped with an optical modulating section 13 for optically modulating the light introduced thereto by an electro- mechanical operation, a supporting substrate 11 disposed on one surface of the modulating section 13, a flat plate 15 fastened to the other surface of the supporting substrate 11, a transparent flat plate 17 arranged to hold the supporting substrate 11 in-between in parallel to the surface of the flat plate 15, and a peripheral wall member 19 encircling the flanks of the flat plate 15 and the flat plate 17. A housing space 21 for housing the modulating section 13 is formed and the outside surface or inside surface of the flat plate 17 is provided with a Fresnel lens 27. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display element for forming an image by optically modulating the introduced light by electromechanical operation and an image display device using the same.

[0002]

2. Description of the Related Art An image display device is built in a finder of a video camera, a digital camera or the like, and a liquid crystal display element (LCD) is often used in this image display device. In an LCD, liquid crystal is placed between a pair of transparent substrates on which a conductive transparent film is formed, sealed, sandwiched between orthogonal polarizing plates, and a voltage is applied to the conductive transparent film so that the liquid crystal molecules are transferred to the substrate. An image is displayed by orienting it perpendicularly to and changing the transmittance of light from the light source device. However,
Since the LCD transmits the light from the light source device between the polarizing plate and the aligned liquid crystal molecules, the light utilization efficiency is lowered and a complicated manufacturing process such as injection and alignment of the liquid crystal is required.
Moreover, there are drawbacks that the applied voltage is high and high-speed driving is difficult.

Therefore, there is a projector device that is capable of high-speed modulation as compared with an LCD, is excellent in displaying a digital image with high image quality, and includes an optical modulator for optically modulating the introduced light from a light source by electromechanical operation. Proposed. In this image display device, for example, as shown in FIG. 15, a light modulator 3 is provided on one surface of a transparent substrate 1 such as a glass substrate, and the light modulator 3 is sealed with a transparent seal 5 to form a seal 5. Transparent plate 5
The lens 7 is spaced apart from the lens a and is opposed to the lens a. And
Light emitted from a light source device (not shown) is transmitted through the transparent flat plate 5b and the transparent substrate 1, and then is optically modulated by the light modulator 3, and the image formed by this is transmitted through the transparent flat plate 5a and further refracted by the lens 7. Then, the image 9 formed on the light modulator 3 is displayed as an enlarged image.

[0004]

However, in the above-mentioned image display device provided with the light modulator for performing the light modulation by the electromechanical operation, the lenses are arranged outside the sealing body so as to face each other. A holding structure for securely fixing the lens to the sealing body is required, and at the same time, the lens must be positioned with high accuracy. Therefore, there is a problem that the workability of assembling the lens is poor and the manufacturing cost is high. Further, since the lens is arranged apart from the sealing body, there is a drawback that the distance between the sealing body and the lens becomes long.
Therefore, it is difficult to reduce the thickness of a main part of the image display device, and there is a problem that the entire image display device cannot be downsized.

The present invention has been made in view of the above circumstances, and provides an image display device which can be thinned by an inexpensive and simple structure and an image display device using the same, and thus the cost of the entire image display device. The purpose is to reduce and downsize.

[0006]

In order to achieve the above object, an image display device according to claim 1 of the present invention comprises an optical modulator for optically modulating introduced light by electromechanical operation,
A support substrate provided with the light modulator on one surface, a flat plate fixed to the other surface of the support substrate, a transparent flat plate arranged in parallel with the plane of the flat plate with the support substrate interposed therebetween, It is characterized by comprising a flat plate and a peripheral wall member surrounding a side surface of the transparent flat plate, forming an accommodation space for accommodating the light modulator, and providing a Fresnel lens on an outer surface or an inner surface of the transparent flat plate.

In this image display device, by providing the Fresnel lens on the transparent flat plate, the workability of assembling the lens is improved and the distance from the lens is improved as compared with the conventional structure in which a separate lens is provided so as to face each other. Becomes shorter. As a result, the image display element can be made inexpensive and thin (small).

An image display device according to a second aspect of the invention is characterized in that a light source for illuminating the light modulation portion is provided at an edge portion of the transparent flat plate in the accommodation space, and light reflected by the light modulation portion is displayed. And

In this image display device, a reflection type image display device can be obtained by providing a light source in the accommodation space and illuminating the light modulator.

According to a third aspect of the present invention, in the image display element, the supporting substrate and the flat plate are made of a material transparent to light that is modulated, and the light is introduced from the flat plate side to the light modulation section, and the light modulation section is introduced. It is characterized by displaying transmitted light from.

In this image display device, the support substrate and the flat plate are made of a transparent material so that the image display device can be a transmission type image display device.

An image display device according to a fourth aspect is characterized in that the Fresnel lens is formed integrally with the transparent flat plate.

In this image display device, the transparent substrate and the Fresnel lens can be constructed by one member. To form the Fresnel lens integrally with the transparent substrate, the transparent substrate may be etched or integrally molded. As a result, the transparent substrate and the Fresnel lens become the same medium, and there is no boundary surface between them, so that there is no reflection at the boundary surface and a high transmittance can be obtained.

An image display device according to a fifth aspect is characterized in that a Fresnel lens formed separately from the transparent flat plate is attached to the transparent flat plate.

In this image display device, the Fresnel lens is formed separately from the transparent substrate, so that the material suitable for each member can be selected. Further, it becomes possible to adopt an optimum manufacturing method for each member, which makes it possible to improve productivity and reduce manufacturing costs. Further, it becomes possible to select and attach a desired one from pre-manufactured Fresnel lenses of different specifications, and it is possible to flexibly deal with the manufacture of a wide variety of image display elements.

An image display device according to a sixth aspect of the present invention is characterized in that the distance between the Fresnel lens and the light modulator is shorter than the focal length of the Fresnel lens.

In this image display device, the image magnified by the Fresnel lens can be observed as an erecting virtual image.

In the image display device according to the seventh aspect, the light modulating section faces the movable section supported by the movable section so as to be movable toward and away from the substrate, and the movable section and the substrate, respectively. A pair of electrodes provided, and the electrostatic force generated by applying a drive voltage between the electrodes causes the movable portion to perform an attracting operation with respect to the substrate, thereby reducing the transmittance with respect to the introduced light by an optical interference effect. It is characterized by changing by.

In this image display element, the movable portion is attracted to the substrate by the electrostatic force, and the transmittance for the introduced light changes. By performing optical modulation by such an optical interference effect, it becomes possible to reduce the size of the image display element, reduce the voltage, and speed up the display operation.

The image display device according to claim 8 is the image display device according to claim 1.
An image display device using the image display element according to claim 7, comprising: a signal processing unit that converts image data for display into a drive signal for the light modulation unit; It is characterized in that an image formed by on / off controlling the light modulator according to data is enlarged and displayed by the Fresnel lens.

In this image display device, the image formed on the light modulator is enlarged and displayed by the Fresnel lens provided on the transparent substrate or the transparent plate. Since the light modulator has a simple structure, the distance between the image display element and the lens is short. As a result, the main part of the projector device becomes thin, and the entire projector device can be downsized.

The image display device according to claim 9 is the image display device according to claim 2.
An image display device using the image display device according to any one of claims 7 to 9, wherein the light source for emitting red, green, and blue light respectively, and the image data for display are a red-compatible frame image and a green-compatible frame. An image and a frame image corresponding to blue are decomposed and converted into a drive signal for the light modulator, and the frame images corresponding to each color are displayed in the light modulator in color order, and are synchronized with the frame image display period of each color. hand,
And a signal processing unit for switching the light of the color corresponding to the displayed frame image from the light source to turn on the light.

In this image display device, while displaying the red-corresponding frame image on the light modulation section of the image display element, the light source emits red light toward the light-modulation section, and similarly, the green-correspondence frame image is displayed. The green light is emitted from the light source during the display, and the blue light is emitted from the light source while the blue corresponding frame image is displayed. As described above, by illuminating the image formed for each color component on the image display element with the illumination light of three colors in synchronization with the color component at high speed, the images of the respective colors are superimposed by the afterimage effect. You can see the color image.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of an image display device and an image display device using the same according to the present invention will be described in detail below with reference to the drawings. 1 is a sectional view showing a first embodiment of an image display device using an image display device according to the present invention, FIG. 2 is a front view of FIG. 1, and FIG. 3 is a partially enlarged view of a light modulator of the image display device. 4 is a cross-sectional view for explaining the operation of the light modulator of the image display device of FIG. 1, and FIG. 5 is a block diagram showing details of the signal processor of FIG. Here, an example is shown in which the image display device is applied as a finder of an optical device.

The image display device 100 of this embodiment is shown in FIG.
As shown in FIG. 3, the supporting substrate 11, the light modulating portion 13 provided on one surface of the supporting substrate 11 for modulating the introduced light by electromechanical operation, and the flat plate 15 fixed to the other surface of the supporting substrate 11. And a transparent plate 17 arranged in parallel with the plane of the flat plate 15 with the support substrate 11 interposed therebetween, and a peripheral wall member 19 surrounding the side faces of the flat plate 15 and the transparent flat plate 17, the flat plate 15, the transparent flat plate 17, the peripheral wall member. A rectangular parallelepiped sealing body 23 that accommodates the light modulator 13 in the accommodation space 21 is formed by 19. Further, a light source 25 for irradiating the light modulating section 13 with illumination light is provided at an edge of a surface of the transparent flat plate 17 facing the light modulating section 13 in the accommodation space 21, and further,
A Fresnel lens 27 is provided on the outer surface of the transparent flat plate 17. The light shield plate 2 is provided between the light source 25 and the transparent flat plate 17.
9 is provided so that the illumination light is not directly irradiated to the display image observation side in front of the optical path. Further, the Fresnel lens may be provided on the inner surface of the transparent flat plate 17.

As shown in FIG. 2, the light source 25 is provided on the entire circumference or a part of the light source disposition region L surrounding the edge of the light modulator 13, and specifically, an LED is preferably used. In the image display device 100 having the above configuration, the light modulation unit 13 and the light source 25 are connected to the signal processing unit 31, and the image data is supplied to the signal processing unit 31 from the input image signal processing unit 33. Are configured.

The image display device 150 having the image display device 100 mounted thereon controls the light modulator 13 to be turned on / off based on an input image signal to form an image 7a. The image 7a is formed by the light source 25. It is a reflection type image display device which illuminates and magnifies the reflected light by the Fresnel lens 27 to directly look at it.

As shown in FIG. 3, the light modulator 13 is composed of light modulators 14 arranged two-dimensionally in a matrix, and each light modulator 14 is individually turned on / off by a signal processor 31. It is controlled by so-called simple matrix drive. Each of the light modulation elements 14 has a flexible movable thin film (movable part) 41 supported on a support substrate 11 via columns 43, as shown in the configuration and operation of the light modulation element in FIG. , Can be moved in the direction toward and away from the support substrate 11. A transparent electrode 45 and a dielectric multilayer film 47 are provided in this order on the movable thin film 41, and a fixed electrode 46 and a dielectric multilayer film 48 are provided in this order on the support substrate 11 correspondingly. Has been.

The transparent electrode 45 may be transparent to the modulated light and is made of, for example, ITO. The dielectric multilayer films 47 and 48 are composed of, for example, a multilayer stack of SiO ₂ / TiO ₂ . When a drive voltage is applied between the transparent electrode 45 and the fixed electrode 46, an electrostatic force is generated between the electrodes 45 and 46, and the movable thin film 41 changes from the state shown in FIG.
As shown in FIG. 4B, the support substrate 11 is suctioned and moved. By such electromechanical operation, the movable thin film 41
The thickness of the gap 49 between the support substrate 11 and the support substrate 11 from t _ON to t
_By changing to _OFF , the optical characteristics of the light modulation element with respect to the introduced light are changed to control the ON / OFF of light. That is, by bending the movable thin film 41, multilayer film interference (Fabry-Perot interference) is generated to perform optical modulation. The details of the light modulation element 14 are described in, for example, Japanese Patent Application Laid-Open No. 11-258558, so refer to them as appropriate.

An image 7a based on image data is displayed by electro-mechanically operating each of the light modulation elements 14 with a drive voltage output from the signal processing section 31 using the above-mentioned light modulation element 14 as one pixel.

This Fresnel lens 27 is a transparent flat plate 17.
The transparent flat plate 17 is formed by etching or integrally molding the surface of
It can also be configured integrally with. As a result, the element structure can be simplified, and no boundary surface exists between the transparent flat plate 17 and the Fresnel lens 27, and there is no reflection at the boundary surface, and a high light transmittance can be obtained. Further, the Fresnel lens 27 may be formed separately from the transparent flat plate 17 and attached to the surface of the transparent flat plate 17. In this case, a material suitable for each member can be selected, and the degree of freedom in design can be increased. Further, it becomes possible to select and attach a desired one from a plurality of Fresnel lenses having different focal lengths prepared in advance.
00 can be applied to a wide range and can have versatility.

Next, the signal processing for driving the image display element 100 will be described. As shown in the block diagram of the configuration of the signal processing unit 31 in FIG. 5, the signal processing unit 31 mainly includes a data format conversion unit 51, a simple matrix drive timing generation unit 53, and a signal level conversion unit 55. is doing. The data format conversion unit 51 converts the input image data 50 into ON / OFF signals to the respective light modulation elements 14 according to the gradation pattern. At this time, for good gradation expression, optimization may be performed by referring to a look-up table LUT prepared in advance and appropriately converting the gradation. The simple matrix drive timing generation unit 53 generates an ON / OFF signal for each light modulation element arranged in a matrix as a simple matrix drive signal, and the signal level conversion unit 55 predetermined the generated simple matrix drive signal. The voltage level is converted into the drive signal of and the signal is sent to the optical modulator 13. As a result, the image 7a based on the image data 50 is displayed on the image display element 100.

Here, a specific control method for driving the image display device 100 in a simple matrix will be described with reference to FIGS. FIG. 6 is an explanatory diagram showing a hysteresis characteristic of light transmittance with respect to an applied voltage, FIG. 7 is a diagram showing a part of a light modulator in which light modulators are two-dimensionally arranged, and FIG. 8 is a summary of input signals to the light modulator. FIG. 9 is an explanatory diagram showing an image data writing signal to the light modulation element. When deforming and elastically restoring the movable thin film by electrostatic force,
The relationship between the voltage applied to the electrodes 45 and 46 and the displacement of the movable thin film 41 shows a hysteresis characteristic. Therefore, the applied voltage Vgs
And the light transmittance T also show a hysteresis characteristic as shown in FIG.

According to this hysteresis characteristic, the light modulation element 14 is turned on when the applied voltage Vgs is Vth (L) or less.
Maintain the (light reflection) state. On the other hand, the applied voltage Vgs is Vs
Above (H), the light modulation element 14 is OFF (light transmission)
Saturate to the state. After that, the light modulation element 14 remains in the OFF state when the applied voltage Vgs is Vth (H) or more. When the applied voltage Vgs becomes Vs (L) or less, the light modulation element 14 is saturated in the ON state. That is, if the applied voltage Vgs is in the range between Vth (H) and Vth (L), the light modulation element 14 may generate T (O) depending on the history of the applied voltage Vgs.
Two states, N) and T (OFF), can be obtained.
When the polarity of the applied voltage Vgs is negative, the characteristics are symmetrical with the above and the vertical axis.

As shown in FIG. 7, the light modulation element 14 having the above characteristics is shown in FIG. 7, in order to simplify the explanation, each intersection Tr (1,1), Tr (1,2), Tr (1,2) of the matrix of 2 rows and 2 columns. 2, 1) and Tr (2, 2), respectively. Each light modulation element 14 is made to correspond to the area of one pixel.

The transparent electrodes 45 on the movable thin film 41 side of the light modulation elements 14 arranged in the same row are commonly connected to each other to serve as scanning electrodes. A potential Vg is applied to this scan electrode. Further, the fixed electrodes 46 on the support substrate 11 side of the light modulation elements 14 arranged in the same column are commonly connected to each other to serve as signal electrodes. A potential Vb is applied to this signal electrode. Therefore, the voltage Vgs between the electrodes 45 and 46 applied to each light modulation element 14 becomes (Vb-Vg). In order to drive the matrix-shaped light modulation element 14, the scan electrodes are scanned in a row-sequential manner in accordance with the scan signals, synchronized with this, and a data signal corresponding to the scanned scan electrodes is applied to the signal electrodes.

Here, as shown in FIG. 8, three kinds of signals (voltages), that is, a reset signal, a selection signal, and a non-selection signal are applied to the scan electrodes. The reset signal is applied to the light modulation element 14 of the row regardless of the previous state of the light modulation element 14.
To OFF (light absorption). The voltage of the scan electrode at this time is Vg (r).

The selection signal is a signal for writing data in the row. Simultaneously with this signal, the state of the light modulation element 14 is determined to be ON (light reflection) or OFF (light absorption) according to the voltage applied to the signal electrode. The voltage of the scan electrode at this time is Vg (s). The non-selection signal is a signal when no selection is made. At this time, the state of the light modulation element 14 does not change regardless of the voltage of the signal electrode, and the previous state is maintained. The voltage of the scan electrode at this time is Vg (ns).

On the other hand, two kinds of signals (voltage), an ON signal and an OFF signal, are applied to the signal electrode. ON signal is
For the light modulation elements 14 in the selected row, the light modulation elements 14
Turn off (light absorption). The voltage of the signal electrode at this time is Vb (on). The OFF signal turns ON the state of the light modulation element 14 with respect to the light modulation element 14 of the selected row.
Set to (light reflection). However, since it is actually assumed that the light modulation element 14 is reset immediately before, when the state of the light modulation element 14 is turned ON (light reflection), the previous state (OFF state) is maintained. The signal to do is all right. The voltage of the signal electrode at this time is Vb (off). That is, the ON / OFF characteristic of the signal to the signal electrode is the ON / OFF of the light modulation element 14.
It is the opposite of the characteristic.

The inter-electrode voltage Vgs of the light modulation element 14 can be divided into the following six types of voltages by the combination of the scan electrode voltage and the signal electrode voltage described above. Also, the voltage between electrodes Vgs
And the characteristics of transmittance give specific conditions. Vgs (r-on) = Vb (on) -Vg (r) ≤ Vs (L) Vgs (r-off) = Vb (off) -Vg (r) ≤ Vs (L) Vgs (s-on) = Vb (on) −Vg (s) ≧ Vs (H) Vgs (s-off) = Vb (off) −Vg (s) ≦ Vth (L) Vgs (ns-on) = Vb (on) −Vg (ns) ≤ Vth (L) Vgs (ns-off) = Vb (off) -Vg (ns) ≥ Vth (H)

Each of the above conditions is shown in FIG.
For example, when the scan electrode voltage Vg is reset Vg (r) and the signal electrode voltage Vb is ON, that is, Vb (on), the signal electrode voltage Vb (thick solid line 61 in the figure) having a value larger than Vs (H) ,
The scan electrode voltage Vg (thick solid line 63 in the figure) having a value between Vs (H) and Vth (L) is subtracted, and the value (thick solid line 65 in the figure) becomes smaller than Vs (L). That is, Vgs (r-on) ≦ Vs (L). In the same manner as above, six kinds of voltages are determined.

Next, a method of writing data in the matrix in which the light modulation elements 14 are two-dimensionally arranged will be described by utilizing the relationship between the inter-electrode voltage Vgs and the transmittance. It is considered that data is written using the matrix of 2 rows and 2 columns shown in FIG. 7 as the matrix. The following ON and OFF data is written in each light modulation element 14 of the matrix. Tr (1,1) → OFF Tr (1,2) → ON Tr (2,1) → ON Tr (2,2) → OFF

A voltage having a waveform as shown in FIG. 9 is applied to the matrix. For example, t1: reset voltage t2: selection voltage t3: non-selection voltage t4: non-selection voltage is applied to the first row Vg (1). T1: don't care t2: ON voltage t3: OFF voltage t4: don't care are applied to the first column Vb (1). As a result, desired data is written in each light modulation element 14 in a row-sequential manner.

That is, for example, in the case of the matrix Tr (1,1) in the first row and the first column, since Vgs: Vb (1) -Vg (1), t1: reset voltage (OFF) t2: ON t3 = state maintenance t4 = state maintenance.

Therefore, the ON state at t2 is maintained (memory), and as a result, the matrix Tr (1,1) is in the state of the optical modulator 14 being "OFF". Similarly, other matrix Tr (1,2) is “ON”, Tr (2,1)
Is "ON" and Tr (2,2) is "OFF". As described above, a desired image can be displayed by turning on the scanning electrodes row by row and applying an arbitrary potential from the signal electrodes in synchronization with the ON.

According to the image display device 150 using the image display device 100, the light modulator 13 is sealed in the housing space 21 of the sealing body 23, and the transparent flat plate 17 of the sealing body 23 is sealed.
Since the Fresnel lens 27 is provided in the lens, the workability of assembling the lens can be improved and the distance to the lens can be shortened as compared with the conventional structure in which a separate lens is provided so as to face each other. As a result, the configurations of the image display element 100 and the image display device 150 can be simplified, and can be made inexpensive and thin.

Next, a second embodiment of the image display device according to the present invention will be described. The above-described image display device of the first embodiment is a configuration example of a single color display, but in the present embodiment, full color display with a plurality of colors, particularly three primary colors of R (red), G (green) and B (blue) is possible. Image display device. FIG. 10 is a block diagram showing the configuration of the image display device of this embodiment. Here, the portions having the same functions as those of the above-described first embodiment are given the same reference numerals, and the description thereof will be omitted. The image display device 250 of this embodiment includes an input image signal processing unit 67, a signal processing unit 31, and three color light sources 25a, 2 of R, G, B.
An image display device 200 having 5b and 25c is provided. The light sources 25a, 25b, 25c are provided on the entire circumference or a part of the light source arrangement area L in FIG. 2 described above, and specifically, R color light emitting LEDs, G color light emitting LEDs, and B color light emitting LEDs are used. In addition to the above, the light source may have a configuration in which a color filter is added to an organic light emitting diode (OLED) or a white light source.

The image signal input to the input image signal processing section 67 is usually an RGB signal in bitmap format,
There are a composite video signal (Y / C signal) in which a luminance signal Y and a color signal C are combined, or a compressed data signal such as JPEG. Although the RGB signal can be used as it is as the image data 50, the compressed data signal is expanded by the expansion processing unit 68 and converted into a Y / C signal, and the Y / C signal is converted into the YC / R signal.
The GB converter 69 converts the RGB signal. These conversion processes can be performed by either software or hardware.

In the signal processing unit 31, the data format conversion unit 51 converts the image data 50 into an ON / OFF signal for each light modulation element according to its grayscale pattern, and the simple matrix drive timing generation unit 53 performs matrix conversion. An on / off signal to each of the arrayed light modulation elements is generated as a simple matrix drive signal. At this time, the light sources 25a, 2
A drive signal for lighting 5b and 25c is also generated at the same time.
Then, the signal level converter 55 converts the generated simple matrix drive signal into a predetermined drive signal in voltage level and sends the signal to the optical modulator 13. As a result, an image based on the image data 50 is displayed on the image display element 200.

FIG. 11 shows the image display device 250 shown in FIG.
The time chart showing the display operation of is shown. The display operation by the signal processing unit 31 will be described with reference to this figure. The signal processing unit 31 uses, as image data, a red image signal 71R,
The green image signal 71G and the blue image signal 71B are supplied to the light modulator 13 in this order. That is, each image signal 71R, 71
G and 71B are supplied frame-sequentially. Then, the red corresponding frame image, the green corresponding frame image, and the blue corresponding frame image are sequentially displayed on the image display element 100 at time ta, and the three color image signals 71R and 71R.
The total display time Ta of G and 71B is, for example, 1/60 s.

Then, the signal processing section 31 supplies drive signals for turning on the light sources to the light sources 25a, 25b, 25c of the respective colors in synchronization with the display of the images of the respective colors.
That is, while the red image signal 71R is supplied to the image display element 100 to display the red corresponding frame image, the red LE is displayed.
The drive signal 73R is supplied to the D25a to supply the red LED 25a.
Light up. Similarly, while the green corresponding frame image is displayed by the green image signal 71G, the green LED 25b is turned on by the drive signal 73G and the blue image signal 71B is displayed.
While the blue corresponding frame image is being displayed, the blue LED 25c is turned on by the drive signal 73B. As described above, when the image formed on the image display element 200 for each color component is illuminated at high speed with the illumination light of three colors in synchronization with the color component, the human eye is affected by the afterimage effect. Will be observed as a color image in which the above images are superimposed.

According to the image display device 250 of the present embodiment, the light sources 25a, 25b and 25c of RGB three colors are arranged so as to face the edge of the light modulator 13, and the light modulator 13 is color-sequentially arranged. By controlling the lighting in synchronism with the image display performed, the image-like reflected light obtained from the light modulator 13 is emitted through the transparent flat plate 17 and the Fresnel lens 27. As a result, the configurations of the image display element 200 and the image display device 250 can be simplified and thinned, and the manufacturing cost can be reduced.

Next, a third embodiment of the image display device according to the present invention will be described. The image display device of this embodiment is configured by using a transmissive image display element. 12 is a cross-sectional view of the image display device of the present embodiment, and FIG. 13 is a cross-sectional view illustrating the operation of the light modulator of the image display device of FIG.

The image display device 300 of this embodiment is similar to that shown in FIG.
As shown in FIG. 2, the support substrate 8 is transparent to the modulated light.
1 and a light modulator 13 provided on one surface of the support substrate 81 for modulating the introduced light by electromechanical operation,
The transparent flat plate 83 fixed to the other surface of the support substrate 81, the transparent flat plate 17 arranged with the support substrate 81 sandwiched in parallel to the surface of the transparent flat plate 83, and the peripheral wall member 19 surrounding the side surfaces of the transparent flat plates 83, 17. The transparent flat plates 83 and 17 and the peripheral wall member 19 form a sealing body 23 that accommodates the light modulator 13 in the accommodation space 21. In addition, the transparent flat plate 17
A Fresnel lens 27 is provided on the outer surface of the. A diffuser plate that diffuses light may be appropriately provided on the outer surface of the transparent flat plate 83.

The image display device 350 equipped with the image display device 300 controls the light modulator 13 on / off based on the input image signal to form an image 7a, and the image 7a is exposed to external light ( Alternatively, a light source may be provided) to illuminate from the back surface, and the transmitted light is magnified by the Fresnel lens 27 and directly viewed to form a transmissive image display device. When the illumination light is obtained from the light source, the signal processing unit 31 may generate a drive signal for the light source to turn on the light source, as in the first embodiment.

In the light modulator 13 of this embodiment, as shown in FIG. 13, the individual light modulator 16 has a transparent support substrate 8
A movable thin film 41 having flexibility is supported on the support via a support column 43, and is movable in a direction toward and away from the support substrate 81. A transparent electrode 4 is provided on the movable thin film 41.
5, the dielectric multilayer film 47 is provided in this order, and the transparent electrode 85 and the dielectric multilayer film 48 are provided in this order on the support substrate 81. For example, glass or transparent resin is used as the support substrate 81, and ITO or the like can be used as the transparent electrodes 45 and 85.

The light modulation element 16 includes transparent electrodes 45, 8
5 is applied, an electrostatic force is generated between the electrodes 45 and 85, and the movable thin film 41 changes from the state shown in FIG. 13A to the supporting substrate 81 side as shown in FIG. 13B. Is sucked and moved to. As a result, the thickness of the gap 49 between the movable thin film 41 and the support substrate 81 is changed from t _off to t _on, and the optical characteristics of the light modulation element with respect to the introduced light are changed to perform on / off control of light. Be done. When the thickness of the void 49 is t _Off , incident light is reflected and is not emitted to the front of the optical path. Further, when the thickness of the void 49 is t _on , incident light is transmitted and emitted to the front of the optical path.

According to the image display device 350 of the present embodiment, an image based on the image signal input by the light modulation operation of the above light modulation element 16 is formed in the light modulation section 13, and this image is output from the rear surface to the external light. Alternatively, it is illuminated by the light from the light source and magnified and observed by the Fresnel lens 27. This makes it possible to simplify the configurations of the image display element 300 and the image display device 350 without providing the lens as a separate body, and to reduce the cost and the thickness.

As shown in FIG. 14, the image display device of each of the embodiments described above converts the video signal (analog signal) output from the video camera 91 into an A / D converter 93.
Alternatively, the image data 50 may be converted into a digital image, and the image data 50 may be processed by the signal processing unit 31 as described above to be displayed on the image display element. Further, although the above-mentioned example describes the display control by the simple matrix drive, the display control may be performed by the active drive system in which an active element such as a transistor is provided for each pixel. In that case, it is possible to display an image by analog control of displacement without providing the light modulation element with a hysteresis characteristic.

Further, according to the image display device of the present invention, in addition to the effects described above, the light modulator 13 includes the sealing body 23.
Since it is hermetically housed in the housing space 21 of the above, it can be shielded from the external atmosphere, and foreign matter such as dust can be prevented from adhering to the portion such as the movable thin film 41 of the light modulator 13. Also,
By enclosing a rare gas or the like in the accommodation space 21, it is possible to prevent the element member from being deteriorated due to a chemical change or the like. As a result, the reliability of the light modulation operation is enhanced, and stable operation can be obtained for a long period of time.

The optical modulator in each of the above-described embodiments uses an optical modulator that performs optical modulation by the electromechanical operation of the interference film, but the present invention is not limited to this, and, for example, Japanese Patent Laid-Open Publication No. As described in JP-A-258558,
An element structure in which a light-shielding film having flexibility is bent by application of an electric field to create a light-shielding state and a light-transmitting state, or a light-shielding light modulation element in which the light-shielding film itself slides and modulates light by application of an electric field Good. Alternatively, a movable thin film may be provided in the total reflection light guide plate so that the movable thin film can be brought close to the total reflection light guide plate, and the total reflection condition is changed by the optical coupling action of the moving thin film approaching / separating operation to perform optical modulation.

Furthermore, the image display device according to the present invention can be appropriately applied not only to the finder but also to other display applications.

[0063]

As described above in detail, according to the image display device of the present invention, the light modulator for optically modulating the introduced light by the electromechanical operation, and the light modulator on one surface. A support substrate provided, a flat plate fixed to the other surface of the support substrate, a transparent flat plate arranged in parallel with the plane of the flat plate across the support substrate, and a peripheral wall member surrounding the flat plate and the side surface of the transparent flat plate. In addition to forming the accommodation space for accommodating the light modulator, and by providing the Fresnel lens on the outer surface or the inner surface of the transparent flat plate, as compared with the conventional structure in which a separate lens is provided facing each other, The workability of assembling the lens can be improved and the distance to the lens can be shortened. As a result, the image display element can be made inexpensive and thin.

According to the image display device of the present invention, it is provided with the above-mentioned image display element and the signal processing section for converting the image data for display into the drive signal of the optical modulation section, and the optical modulation is performed according to the image data. Since the image formed by controlling the on / off of the part is enlarged and displayed by the Fresnel lens, the light modulation part has a low cost and simple structure, and the image display element is thin The main part of the display device can be thinned, and as a result, the entire image display device can be downsized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an image display device using an image display element according to the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a partially enlarged view of a light modulator of the image display device.

FIG. 4 is an explanatory diagram showing a configuration and an operation of a light modulation element.

FIG. 5 is a block diagram showing a configuration of a signal processing unit.

FIG. 6 is an explanatory diagram showing a hysteresis characteristic of light transmittance with respect to an applied voltage.

FIG. 7 is a diagram showing a part of a light modulator in which light modulators are two-dimensionally arranged.

FIG. 8 is an explanatory diagram collectively showing input signals to the light modulation element.

FIG. 9 is an explanatory diagram showing a signal for writing image data to the light modulation element.

FIG. 10 is a block diagram illustrating a configuration of an image display device according to a second embodiment.

11 is a time chart showing a display operation of the image display device shown in FIG.

FIG. 12 is a sectional view of an image display device according to a third embodiment.

13 is a cross-sectional view illustrating the operation of the light modulator of the image display device shown in FIG.

FIG. 14 is a block diagram showing signal processing when image data is obtained from a video camera.

FIG. 15 is a main part configuration diagram showing an image forming unit of a conventional image display device.

[Explanation of symbols]

7a image 11 Support substrate 13 Light modulator 14,16 Light modulator 15 flat plate 17 Transparent plate 19 Peripheral wall member 21 accommodation space 23 Sealed body 25 light sources 25a, 25b, 25c light source 27 Fresnel lens 31 Signal processing unit 33 Input image signal processing unit 41 Movable thin film (movable part) 45,85 transparent electrode 46 fixed electrode 47,48 Dielectric multilayer film 50 image data 51 Data format converter 53 Simple matrix drive timing generator 55 Signal level converter 71R Red image signal 71G green image signal 71B blue image signal 73R, 73G, 73B drive signal 81 Support substrate 83 Transparent plate 100,200,300 Image display device 150,250,350 Image display device C color signal Y luminance signal L light source arrangement area T light transmittance

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H041 AA05 AA23 AB00 AB12 AB38                       AB40 AC06 AZ05 AZ08                 5C058 AB06 BA35 EA01 EA27 EA34                       EA51

Claims (9)

[Claims] 1. A light modulator for optically modulating the introduced light by electromechanical operation, a support substrate provided with the light modulator on one surface, and a flat plate fixed to the other surface of the support substrate.
A transparent flat plate arranged in parallel to the plane of the flat plate with the support substrate sandwiched between the flat plate and a peripheral wall member surrounding a side surface of the transparent flat plate is formed, and an accommodation space for accommodating the light modulator is formed. An image display device characterized in that a Fresnel lens is provided on an outer surface or an inner surface of the transparent flat plate. 2. The image according to claim 1, wherein a light source for illuminating the light modulation section is provided at an edge of the transparent flat plate in the accommodation space, and reflected light from the light modulation section is displayed. Display element. 3. The support substrate and the flat plate are made of a material transparent to light that is modulated, and light is introduced from the flat plate side to the light modulation section to display transmitted light from the light modulation section. The image display device according to claim 1, wherein: 4. The image display device according to claim 1, wherein the Fresnel lens is formed integrally with the transparent flat plate. 5. The image display device according to claim 1, wherein a Fresnel lens formed separately from the transparent flat plate is attached to the transparent flat plate. 6. The image display device according to claim 1, wherein a distance between the Fresnel lens and the light modulator is shorter than a focal length of the Fresnel lens. 7. The light modulating section includes a movable section movably supported in a direction toward and away from the substrate, and a pair of electrodes provided to face both the movable section and the substrate. Then, the movable part is attracted to the substrate by an electrostatic force generated by applying a drive voltage between the electrodes, and the transmittance with respect to the introduced light is changed by an optical interference effect. The image display device according to any one of claims 1 to 6. 8. An image display device using the image display device according to claim 1, wherein the image display device converts a display image data into a drive signal for the light modulator. An image display device, comprising: a processing unit, wherein an image formed by on / off controlling the light modulation unit according to the image data is enlarged and displayed by the Fresnel lens. 9. An image display device using the image display device according to claim 2, wherein the light source emits red light, green light, and blue light, respectively, and image data for display is provided. The red color corresponding frame image, the green color corresponding frame image, and the blue color corresponding frame image are decomposed and converted into a drive signal for the light modulating unit, and the color corresponding frame images are displayed in the light modulating unit in color order, and the respective colors are displayed. An image display device, comprising: a signal processing unit that switches the color of light corresponding to the displayed frame image from the light source to light in synchronization with the frame image display period.