JP2002214579A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize high definition images at a low cost even with an image display element of a small number of pixels. SOLUTION: Optical path deflecting means 4 for deflecting the optical path of the incident light from the pixels of the image display element driven by being finely divided in terms of time to plural image sub-fields has two transparent substrates 41 and 42 including liquid crystal layers 45 and transparent electrodes 43 and 44 disposed on the respective transparent substrates 41 and 42. The transparent electrodes 43 disposed on at least one transparent substrate 41 are transparent electrode arrays formed of a disposition pitch made correspondent to the pixel pitch of the pixels described above. The liquid crystal layers 45 are controllable in refractive index distributions by the voltage impression between the transparent electrode 43 arrays and the transparent electrodes 44 on the other transparent substrate 42 and further, the voltage impression state to the transparent electrodes 43 and 44 is changed by each of the image sub-fields in synchronization with the driving of the image display element, by which the images are displayed at the doubled apparent number of the pixels of the image display element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device in which a plurality of pixels capable of controlling illumination light are two-dimensionally arranged on the basis of image information. The present invention relates to an image display device for observing an image, and more particularly to an image display device for displaying a high-definition image by a pixel shift method in which the number of actual pixels is increased by shifting an optical path. Further, the image display device according to the present invention can be applied to an electronic display device such as a projection display and a head-mounted display.

[0002]

2. Description of the Related Art An image display device for observing an image display element having a plurality of pixels capable of controlling illumination light based on image information as an image enlarged by a lens has been already known as a front projector, a rear projector, and a head. Widely used by trade names such as mounted displays. Further, as such an image display element, a CRT (Ca
thode Ray Tube), LCD panel, DMD (Digital M
icro-mirror Device: a product name of an image display device manufactured by Texas Instruments (USA)) is already used as a product, and an inorganic EL (Electro-Lumi) is used.
nescence), inorganic LED (Light Emitting Diode),
Organic LEDs are also being studied.

On the other hand, as the image display device for observing a small image display element at an equal magnification instead of observing it as an image magnified by a lens, the above-described CRT, liquid crystal panel, inorganic EL, inorganic LED, organic LED In addition to LEDs, plasma displays, fluorescent display tubes, and the like have already been used as products, and FEDs (Field Emission Displays: PALCs)
ma Addressing Liquid Crystal Display) is also being studied. Note that image display devices are broadly classified into two types, a self-luminous type and a spatial light modulator type, and each type has a plurality of pixels capable of controlling illumination light. Is what it is.

A common problem in such an image display device is to increase the resolution, that is, to increase the number of pixels.
An image display device for HDTV (High Definition Television) having about 1000 scanning lines for broadcast display has been commercialized, and a scanning line 2000 for high resolution display of a workstation computer has been commercialized.
About this developed product (for example, the QS of the image display device manufactured by IBM Japan at the '98 flat panel display exhibition)
XGA, ie, 2048 scanning lines, and QUXGA, ie, 2,400 scanning lines of an image display device manufactured by Toshiba Corporation in the '99 Electronic Display Exhibition, have also been announced as technologies using liquid crystal panels. However, in the case of increasing the actual number of pixels, the yield of the liquid crystal panel is reduced, the cost is increased, the brightness and contrast are reduced, or the aperture ratio is reduced, or There are many issues such as an increase in power consumption.

As a solution to such a problem, Japanese Patent Application Laid-Open No. 4-113308 entitled "Projection Display Apparatus"
No. 289004, “Optical switch”, JP-A-6-324
No. 320, “Image display device, resolution improvement method of image display device, imaging method, recording device and reproducing device”, etc., use a single image display element to reduce the apparent number of pixels to the actual number of pixels. An image display device that performs interlaced display with twice the number of pixels is disclosed. In addition, Japanese Patent Application Laid-Open
Japanese Patent Publication No. 36054 discloses an image display device using a single image display element and having an apparent number of pixels that is four times or more the actual number of pixels. In any case, these image display devices deflect the optical path of the light emitted from the image display element at high speed in a time-division manner, and increase the apparent number of pixels, a so-called method.
Pixel shift technology is adopted.

A specific embodiment of the so-called pixel shift technique, in which the number of images on the image display element is apparently multiplied to obtain a high-resolution image display, is disclosed in, for example, Japanese Patent Laid-Open No.
-324320, "Image display device, resolution improvement method of image display device, imaging method, recording device, and reproduction device"
And Japanese Patent Application Laid-Open No. 10-020242, entitled “Projection Display Device”, and US Pat. No. 6,082,862, “IMAGE TILING T
ECHNIQUE BASED ON ELECTRICALLY SWITCHABLE HOL
OGRAMS "and the like.

The pixel shift technique disclosed in Japanese Patent Application Laid-Open No. 6-324320 discloses an image display device, such as an LCD, in which an optical path is switched by an optical member for each image field without increasing the number of pixels. This is to improve the resolution of an image apparently. That is, in an image display device in which an image is displayed by each of a plurality of pixels arranged in the vertical direction and the horizontal direction emitting light in accordance with a display pixel pattern (that is, display image information), an observer or An optical member for deflecting the optical path for each image field is arranged between the screen and the screen. Further, for each of the image fields, the resolution of the image display device is improved by displaying the display pixel pattern in a state where the display position is shifted according to the deflection of the optical path on the image display device. is there.

The pixel shift technique disclosed in Japanese Patent Application Laid-Open No. H10-020242 is to perform a pixel shift by combining an image display element and a microlens array and vibrating the microlens array. That is, the microlens array is arranged on the optical path from the light modulation element to the projection lens, and one convex lens is formed corresponding to four pixels of the light modulation element. On the other hand, the actuator is configured to vibrate each microlens of the microlens array in a vertical direction and a horizontal direction, and by driving the actuator in synchronization with a field signal supplied to the light modulation element, The microlens array is configured to move or vibrate in a horizontal / vertical direction orthogonal to the optical axis of the light incident on the microlens array, thereby performing a pixel shift.

The pixel shift technique disclosed in US Pat. No. 6,082,862 is applied to a projection system using a holographic optical element capable of electrical switching, and is a holographic optical element made of a liquid crystal material. The element is configured to change the angle of the optical path at high speed to shift the position of the display image at high speed.

[0010] For example, for example, "Focus variable lens using liquid crystal" (Susumu Sato; Optical Technology Contact, VOL32,
No. 11, p. 24-p. 28, 1994) describes a technique for changing a lens formation position by selectively applying a voltage in synchronization with an image field signal using a liquid crystal microlens array having a circular hole-shaped electrode pattern. Have been.

On the other hand, as an optical path deflecting means for realizing such a pixel shift technique, for example, Japanese Unexamined Patent Publication No.
Japanese Patent No. 3232420 entitled "Image Display Device, Resolution Improvement Method of Image Display Device, Imaging Method, Recording Device and Reproducing Device" describes a mechanism for combining an electro-optical element and a birefringent material,
A lens shift mechanism, a variangle prism, a rotating mirror, a rotating glass, and the like are disclosed.
Japanese Patent Application Laid-Open No. 313116 discloses an optical path deflecting means for mechanically swinging an image display element itself at a high speed by a distance smaller than a pixel pitch using an actuator composed of a piezoelectric element or the like.

In Japanese Patent Application Laid-Open No. Hei 7-104278 entitled "Optical Axis Converter and Video Projector", in addition to the optical path deflecting means using a birefringent element such as a quartz plate,
Means for deflecting the optical path by mechanically vibrating one of a pair of wedge prisms having inclined surfaces opposed at a predetermined interval is disclosed.

Also, in Japanese Patent Application Laid-Open No. 10-133135, "a light beam deflecting device", a translucent piezoelectric element disposed on a traveling path of a light beam, and a transparent electrode provided on a surface of the piezoelectric element are provided. Applying a voltage to the piezoelectric element through the electrode to change the optical path length between the light beam incident surface and the light beam exit surface of the piezoelectric element to deflect the optical axis of the light beam. By changing the thickness that is the optical path length of the piezoelectric element,
A method of shifting the optical path has been proposed. That is, the invention according to Japanese Patent Application Laid-Open No. Hei 10-133135 eliminates the need for a rotary mechanical element, realizes miniaturization, high precision and high resolution, and is hardly affected by external vibration. It is intended to provide.

Further, in Japanese Patent Application Laid-Open No. 6-208345, entitled "Image Display Device",
As in the case of Japanese Patent Publication No.
A method of changing the shift amount of the optical path by switching the thickness of the transparent refraction plate and the inclination angle with respect to the optical axis is described. An example is shown in which the angle is partially different, and the circular rotator is made of rotating glass.

Further, Japanese Patent Application No. 2000-362090, filed by the present applicant, proposes a technique using a Bragg diffraction element made of a polymer dispersed liquid crystal as an optical path deflecting means. The technology is
Although a pixel reduction element is separately required to improve light use efficiency, it has a feature of having a high-speed response based on a minute liquid crystal droplet structure.

Further, as a light deflection technique using a liquid crystal,
“LIGHT SCANNER EMPLOYING ANEMATIC LIQUID CRY
STAL ”(IBM Technical Disclosure Bulletin, Vo
l. 15, No. 8 (1973)), in which the orientation angle of a nematic liquid crystal is changed to bend the optical path of linearly polarized light.

Another example of a light deflecting technique using a liquid crystal is disclosed in "LARGE-ANGLE BEAMDEFLCTOR USING L."
IQUID CRYSTAL ”(ELECTRONICS LETTERS, Vol. 1
1, No. 16 (1975)), which applies a non-uniform electric field to a nematic liquid crystal to bend the optical path of linearly polarized light.

Further, as a technique relating to a liquid crystal microlens, “Liquid crystal microlens” (O Plus E, Vo)
l. 20, No. 10 (1998)), Patent No. 0301
No. 6744, "Liquid crystal microlens", JP-A-11-10
No. 9303, “Optical coupler”, JP-A-11-10930
There is a technique disclosed in, for example, Japanese Patent Publication No. 4 “Optical coupler”.

"Liquid crystal microlens" (O Plus E,
Vol. 20, No. 10 (1998)), the focus can be moved in directions other than the optical axis direction by making the electric field distribution asymmetric using a liquid crystal microlens having an electrode division structure.

The technique disclosed in Japanese Patent No. 03016744, which forms a polymer by photopolymerization in a nematic liquid crystal, has a memory property and has a feature that the lens characteristics can be changed.

The technology disclosed in Japanese Patent Application Laid-Open Nos. 11-109303 and 11-109304 discloses a technique of using a liquid crystal microlens in which circular hole-shaped pattern electrodes are arranged in an array. The distance of the lens is variable, the light coupling efficiency of the optical interconnection element is variable, and the focus position can be controlled by the divided electrodes.

[0022]

However, the various types of optical path deflecting means disclosed as the prior art as described above have the following problems. For example, an optical path deflecting means using a combination mechanism of a member exhibiting an electro-optical effect and a birefringent material has a high response speed and is an optical path deflecting means conventionally used as an optical distribution and optical switch in the optical communication field. This is a known technique. However, the optical path deflecting means using the combination mechanism of the electro-optical element and the birefringent material requires a relatively large crystal birefringent material, and thus has a problem that the apparatus cost is increased.

When a lens shift mechanism is used as the optical path deflecting means, that is, when a lens is reciprocated linearly mechanically, or when a mechanism for rotating a rotating mirror is employed, a driving system for such movement is provided as follows. A voice coil, a piezoelectric element, a bimorph, a step motor, a solenoid coil and the like are described in JP-A-6-324320, and a piezoelectric element or a moving coil is used as a drive system for vibrating a wedge prism. An example is described in JP-A-7-104278. However, no matter which drive system is used, a lens or a prism is mechanically and repeatedly moved with a period of about several tens to several hundreds of Hz, which causes a problem of generating vibration and noise. Will accompany.

Also, in the case where a vari-angle prism used as a so-called camera shake preventer of a camera-integrated VTR is used as an optical path deflecting means, a bellows connecting two substrates in order to change the apex angle of the prism. Performs reciprocating motion, so that generation of vibration and noise is still a problem.

In the system disclosed in Japanese Patent Application Laid-Open No. 5-313116, in which the image display element itself is mechanically swung at high speed, since the optical system is fixed, various aberrations are less generated and high-definition display is possible. Although there are advantages, it is necessary to translate the image display element itself accurately and at high speed, so that not only the accuracy and durability of the movable portion of the image display element are required, but also mechanical high-speed vibration operation is performed. As a result, the generation of vibration and noise is still a problem.

Further, the method of changing the optical path length of the transparent piezoelectric element disclosed in Japanese Patent Laid-Open No. Hei 10-133135 requires a relatively large transparent piezoelectric element, which causes a problem of an increase in apparatus cost.

The method of changing the optical path length by a circular rotator using a rotating glass disclosed in Japanese Patent Laid-Open Nos. 6-208345 and 6-324320 is not a simple method of forming a single circular rotator. There is a problem that the optical path shift is limited to only the original direction and that a relatively large circular rotator is required, so that the entire optical system becomes large.

Further, the following problems also exist in the prior art in which an optical path deflection using a liquid crystal or a liquid crystal microlens is applied to an image display device. For example, "Variable focus lens using liquid crystal" (Susumu Sato; Optical Technology Contact, VO
L32, No. 11, p. 24-p. 28, 1994)
In the case of using an optical path deflecting unit that changes a lens forming position by using a liquid crystal microlens array having a circular hole-piercing electrode pattern as disclosed in US Pat. Although it is relatively easy to change it, there is a problem that the condensing position (that is, the focal position) cannot be changed in the direction of the arrangement plane of the liquid crystal microlens array.

As a technique for changing the light condensing position in the direction of the arrangement surface of the liquid crystal microlens array, Japanese Patent Application Laid-Open No. H11-109303 discloses an "optical coupler".
And Japanese Patent Application Laid-Open No. 11-109304, "Optical Coupler", discloses a control technique using divided electrodes. However, when the liquid crystal microlenses having the divided electrodes are arranged in an array, the wiring to each divided electrode becomes complicated, so that the formation interval of the liquid crystal microlenses must be set relatively wide. Therefore, it is suitable when the installation interval may be relatively wide, such as coupling between a semiconductor laser array and a plurality of optical fibers, but the installation interval is relatively narrow, such as the pixel pitch of an image display element. in case of,
There is a problem that the aperture ratio of the lens forming portion is reduced.

Further, as a light deflection technique using a liquid crystal,
“LIGHT SCANNER EMPLOYING A NEMATIC LIQUID C
RYSTAL ”(IBM Technical Disclosure Bulletin, V
ol. 15, No. 8 (1973)), “LARGE-ANGLE
BEAM DEFLCTOR USING LIQUID CRYSTAL ”(ELECTR
ONICS LETTERS, Vol. 11, No. 16 (197
As described in 5)), etc., any of the techniques for bending the optical path of linearly polarized light by changing the orientation angle of the nematic liquid crystal or applying an inhomogeneous electric field to the nematic liquid crystal is a single technique. It is applied to a beam deflector and cannot be applied to pixel shift of a two-dimensional image as it is.

Further, as a technique relating to a liquid crystal microlens, “Liquid crystal microlens” (OPlus E, Vol.
20, No. 10 (1998)), the liquid crystal microlens technology of the electrode division structure in which the electric field distribution is asymmetric is suitable for controlling the deflection direction of a single beam two-dimensionally. In such a case, since the electrode wiring becomes complicated, it is not suitable for application to an array beam deflecting device like an image display element.

The present invention has been made in view of the above-described problems, and has a relatively simple electrode configuration utilizing an electro-optical effect without providing a mechanical vibration mechanism. It is an object of the present invention to provide an image display device capable of obtaining a high-definition image by apparent pixel multiplication without causing a shift and reducing the light use efficiency.

That is, the first problem is that even when the current relatively low-resolution image display element is used as it is, a non-uniform electric field is formed in the liquid crystal layer instead of using a mechanical moving mechanism. Due to the refractive index distribution in the liquid crystal layer caused by this, the deflection of the optical path can be realized with a relatively simple configuration, and low-cost, vibration-free and noise-free, high-resolution image display is possible. An image display device is provided.

The second problem is that even when the current relatively low-resolution image display device is used as it is,
With a simple configuration, the optical path of the image light from the pixels of the image display element is focused, and at the same time, by realizing the liquid crystal microlens effect that shifts the focusing position, the pixel shift function and the pixel reduction function are compatible. Another object of the present invention is to realize a low-cost, high-resolution apparently high-luminance image display device with high light use efficiency.

A third problem is that a concave lens array is arranged on the exit surface side from the optical path deflecting means having a liquid crystal microlens effect, and the emitted light from the optical path deflecting means (ie, the deflected image light) is parallelized. The object of the present invention is to realize a high-definition image quality in which the pixel pitch is constant over the entire display image area with respect to a display image having a high resolution apparently by lightening.

The fourth problem is that the pixel shift in the horizontal direction and the pixel shift in the vertical direction of the image are combined to perform apparent pixel multiplication in the two-dimensional direction, thereby achieving higher definition. It is an object of the present invention to provide an image display device capable of displaying images at different degrees.

[0037]

According to a first aspect of the present invention, there is provided an image display element in which a plurality of pixels capable of controlling illumination light are two-dimensionally arranged based on image information, and Display driving means capable of driving the image display element by temporally dividing an image field indicating a display time into a plurality of image subfields, and being driven for each of the image subfields by the display driving means By having an optical path deflecting means for deflecting the optical path of the image light incident from each of the pixels, the image display device capable of multiplying and displaying the apparent number of pixels of the image display element, The optical path deflecting means has two transparent substrates, a transparent electrode disposed on each of the transparent substrates, and a liquid crystal layer interposed between the two transparent substrates, and among the transparent electrodes The transparent electrode disposed on at least one of the transparent substrates is a transparent electrode array formed in an array at an arrangement pitch corresponding to a pixel pitch of the pixel, and the liquid crystal layer includes: It is a liquid crystal layer capable of controlling a refractive index distribution by a voltage application state between a transparent electrode array and a transparent electrode on the other transparent substrate, and the image is synchronized with the display driving means. An image display device wherein the state of voltage application to the transparent electrode array is changed for each subfield.

According to a second aspect of the present invention, in the image display device according to the first aspect, the arrangement pitch of the transparent electrode arrays formed in an array at an arrangement pitch corresponding to a pixel pitch of the pixels. However, the present invention is not limited to an interval that is one-to-one with the pixel pitch, but is also an interval equal to an integral multiple of the pixel pitch or a fraction of the integer.

According to a third aspect of the present invention, in the image display device according to the first or second aspect, the arrangement pitch of the transparent electrode array is such that a plurality of transparent electrodes are set as one set. An image display device characterized in that the arrangement pitch is provided for each image.

According to a fourth aspect of the present invention, in the image display device according to any one of the first to third aspects, the optical path deflecting means is connected to the transparent electrode array arranged at a predetermined arrangement pitch. Depending on the voltage application state, a liquid crystal microlens array capable of condensing the image light incident from each of the pixels is formed, and the positions of the transparent electrodes to which a voltage is applied in the transparent electrode array are adjacent. The image display is characterized in that the focal position of the liquid crystal microlens array can be switched in time sequence along the arrangement direction of the transparent electrode array by being switched in time sequence between the transparent electrodes. Device.

According to a fifth aspect of the present invention, in the image display device of the fourth aspect, the optical path deflecting unit emits the light condensed by the liquid crystal microlens array as parallel light parallel to the optical axis. An image display device comprising a concave lens array that can be provided on an emission surface side of the optical path deflecting unit.

According to a sixth aspect of the present invention, in the image display device according to any one of the first to fifth aspects, the two-dimensional arrangement direction of the pixels is along a first pixel arrangement direction of the pixels. A first optical path deflecting means capable of deflecting an optical path of the incident image light and / or moving a focal position where the image light is condensed, and a second pixel arrangement direction of the pixel Along, the optical path of the image light incident through the first optical path deflecting means, and / or the second optical path deflection capable of moving the focal position where the image light is condensed Means, and further, the direction of the plane of polarization of linearly polarized light,
A polarization plane rotating unit capable of rotating from the first pixel arrangement direction to the second pixel arrangement direction is disposed between the first optical path deflection unit and the second optical path deflection unit. An image display device characterized in that:

[0043]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an image display device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating an outline of a configuration example of an image display device according to the present invention. In FIG. 1, reference numeral 1 denotes a light source for illumination, which quickly or whitely emits light of any color.
Any type or type of light source can be used as long as it can be N / OFF. For example, L
An ED lamp, a laser light source, a white lamp light source, or the like is arranged in a two-dimensional array, and a combination of such a light source and a shutter that operates at a high speed can be used as a light source for illumination. Reference numeral 2 denotes an illumination device for uniformly irradiating the light emitted from the light source to the image display element 3, and includes a diffusion plate 2a, a condenser lens 2b, and the like.

And 3, spatial light modulation of uniform illumination light incident from the illumination device 2 on the basis of image information for each of a plurality of image subfields obtained by further subdividing an image field temporally. An image display element that emits image light. As the image display element 3, a transmission type liquid crystal light valve, a reflection type liquid crystal light valve, a DMD element, or the like can be used. 4 for each image subfield:
An optical path deflecting unit that deflects the optical path of the image light emitted from the image display element 3 and emits it as deflected image light.
The optical path deflecting means 4 can display an image pattern in which an image display position projected on the screen 6 is shifted according to the amount of deflection of the optical path for each image subfield. An image can be displayed as the apparently multiplied number of pixels of the actual number of pixels.

Reference numerals 5 and 6 denote optical members for observing an image pattern displayed on the image display element 3, which indicate a projection lens and a screen, respectively. Further, reference numeral 7 denotes a light source driving unit for driving the light source 1, 8 denotes a display driving unit for driving the image display element 3, and 9 denotes a display driving unit.
Is an optical path deflection driving means for driving the optical path deflection means 4. Reference numeral 10 denotes an image display control circuit for controlling the entire image display device including the light source driving unit 7, the display driving unit 8, the optical path deflection driving unit 9, and the like.

Next, the operation of the image display device shown in FIG. 1 will be described. The light radiated from the light source 1 under the control of the light source driving means 7 becomes illumination light uniformed by the diffusion plate 2a, and is emitted by the condenser lens 2b.
Critically illuminates the image display element 3 controlled by the display driving means 8 operating in synchronism with the display. Here, as an example of the image display element 3, a transmissive liquid crystal panel, that is, a transmissive liquid crystal light valve is used. The illumination light spatially modulated by the image display element 3 composed of the transmission type liquid crystal light valve enters the optical path deflecting means 4 as image light, and the emitted light emitted from the optical path deflecting means 4 is deflected image light. After being enlarged by the projection lens 5, it is projected on the screen 6. That is, the image light is arbitrarily shifted in the pixel arrangement direction in accordance with a drive signal from the optical path deflection driving means 9 by the optical path deflection means 4 arranged behind the image display element 3 composed of a transmission type liquid crystal light valve. The light is emitted as deflected image light shifted (deflected) by the distance of, and is projected onto the screen 6 via the projection lens 5.

In FIG. 1, an optical path deflecting element serving as an optical path deflecting means 4 is disposed immediately after an image display element 3 comprising a transmissive liquid crystal light valve. The present invention is not limited to this case, and may be arranged immediately before the screen 6 or the like. However, when the optical path deflecting device 4 is disposed in the vicinity of the screen 6, the size of the optical path deflecting element forming the optical path deflecting means 4,
It is necessary to set the arrangement pitch of the transparent electrodes forming the optical path deflecting element according to the screen size and the pixel size at the position where the optical path deflecting means 4 is arranged. But,
Regardless of the arrangement position of the optical path deflecting unit 4, the amount of shift (deflection) of the optical path of the deflected image light is
It is preferable that the pixel pitch is an integer fraction of the pixel pitch.

That is, when the pixel multiplication is performed twice in the pixel arrangement direction, the shift amount of the optical path of the deflected image light is set to 画素 of the pixel pitch and tripled in the arrangement direction. When performing pixel multiplication, it is desirable to make the pixel pitch 1/3. Further, if the amount of shift of the optical path of the deflected image light is larger than the pixel pitch due to the configuration of the optical path deflecting means 4, the shift amount of the optical path is set to a distance of (integer multiple + 1 / integer) of the pixel pitch. May be set. In the present embodiment, as shown on the optical path deflecting means 4 and the screen 6 in FIG. Although an example in which pixel shift is performed is shown, the optical path deflecting unit 4 performs image shift based on image information of an image subfield corresponding to a shift position of a pixel deflected in the horizontal direction.
By driving the image display element 3 composed of a transmissive liquid crystal light valve by the display driving means 8, as shown in FIG.
An apparent pixel multiplication effect is obtained, and a high-definition image higher than the resolution of the used transmissive liquid crystal light valve can be displayed.

FIG. 2 is a schematic diagram showing an example of apparent pixel doubling displayed on the screen 6. The number of pixels is twice as large as the actual number of pixels in the transmissive liquid crystal light valve. 2 shows an example in which an image is displayed on the screen 6. That is, in FIG. 2, the optical path is deflected in the horizontal direction, which is the pixel arrangement direction, by the amount displayed as the shift amount between the pixels adjacent to each other in the horizontal direction displayed as the pixel pitch, By displaying the upper pixel, it is possible to display a high-definition image having a resolution twice as many as the actual number of pixels of the transmission type liquid crystal light valve.

In FIG. 1, a monochromatic LED is used as the light source 1.
An example of a monochromatic image display device using a lamp and a single-plate transmission type liquid crystal light valve as the image display element 3 is shown, but a light source of three primary colors and a lighting device are used as the light source 1 and the lighting device 2, respectively. Further, by using three image display elements as the image display element 3, a full-color image in which three primary color images are mixed can be displayed. Further, even in the case of a single-plate image display element 3, a full-color image can be displayed by using a field sequential method in which the image display element 3 is illuminated with illumination light from a light source 1 that emits three primary color lights in time sequence. You can also. In such a case, the illumination may be performed by mixing the light paths from the light sources 1 of the three primary colors with a cross prism, or the time-sequential three primary colors may be generated by combining a white lamp light source and a rotating color filter. good.

The present embodiment is characterized in that a liquid crystal cell whose refractive index distribution can be controlled by applying a voltage is used as the optical path deflecting means 4. The liquid crystal cell has two transparent substrates, a transparent electrode disposed on each of the transparent substrates, and a liquid crystal layer interposed between the two transparent substrates, and among the transparent electrodes The transparent electrode disposed on at least one of the transparent substrates is a transparent electrode array formed in an array at an arrangement pitch corresponding to a pixel pitch of the pixel, and the liquid crystal layer is It is a liquid crystal layer capable of controlling a refractive index distribution depending on a voltage application state between the transparent electrode array and the transparent electrode on the other transparent substrate. Further, there is provided an optical path deflection driving means 9 capable of changing a voltage application state to the transparent electrode array for each image subfield in synchronization with a display driving means 8 for driving the image display element 3. I have.

As a material of the transparent substrate, a material having high transparency such as glass and plastic can be used. The material of the transparent electrode is ITO.
(Indium Tin Oxide) etc. can be used. The transparent electrode layer is provided so as to be on the liquid crystal phase layer side. Also,
When the transparent substrate itself has conductivity, the transparent substrate itself can be used as an electrode. Further, on at least one transparent substrate side, the transparent electrodes are formed in an array corresponding to a pixel pitch.
Here, the pitch of the electrode array of the transparent electrodes is not limited to the case where the pitch corresponds to the pixel pitch on a one-to-one basis.
In order to obtain a desired refractive index distribution, the refractive index may be set to an integral multiple or a fraction of the pixel pitch. Also,
There may be a case where a plurality of the lines of the transparent electrode are set as one set and each set corresponds to a pixel pitch.

The surface of the transparent electrode in contact with the liquid crystal layer is preferably subjected to an alignment treatment so that liquid crystal molecules are aligned. As the alignment treatment, a normal alignment film such as polyimide used for TN liquid crystal, STN liquid crystal, or the like can be used. Further, it is preferable to perform a rubbing treatment or a photo-alignment treatment. Further, an insulating film may be provided on the surface of the transparent electrode.

Here, as the liquid crystal material forming the liquid crystal layer, a general nematic liquid crystal can be used, but it is preferable that the birefringence Δn and the dielectric anisotropy Δε are large. In particular, it is preferable that the ordinary light refractive index of the liquid crystal material is about 1.5 to 1.6, which is close to the refractive index of the glass substrate, and the extraordinary light refractive index is as large as about 1.7 to 1.8. Also,
The thickness of the liquid crystal layer is set by the thickness of the spacer member disposed between the transparent substrates, and a desired amount of optical path deflection and response speed can be obtained according to the birefringence Δn and the dielectric anisotropy Δε. Optimized for It is preferable that the disposing position of the spacer member is disposed only on the periphery of the liquid crystal layer so as not to hinder the transmission of light in the liquid crystal cell.

Next, the optical path deflecting operation in the liquid crystal cell forming the optical path deflecting means 4 will be described in detail with reference to FIGS. FIG. 3 is a cross-sectional view of the liquid crystal cell when the liquid crystal cell serving as an optical path deflecting means is cut along the optical axis. The image light which is the light emitted from No. 3 is incident. FIG. 4 is a schematic diagram showing a refractive index distribution with respect to linearly polarized light in the optical path deflecting means 4 shown in FIG. 3. The upper transparent electrode 43 of the liquid crystal cell forming the optical path deflecting means 4 shown in FIG. (I.e., a diagram showing the positional relationship with the transparent electrode array arranged on the downstream side of the optical path) and the refractive index distribution of the liquid crystal layer 45 schematically.

In FIG. 3, reference numerals 41 and 42 denote transparent substrates for enclosing the liquid crystal layer 45, respectively.
Reference numeral 4 denotes a transparent electrode for applying an electric field to the liquid crystal layer 45. Note that, on the transparent substrate 41 on the downstream side of the optical path, that is, on the upper side of the paper, the lines of the transparent electrodes 43 are formed in an array corresponding to the pixel pitch of the image display element 3. Also,
In the present embodiment, an example is shown in which the positions of the lines of the transparent electrodes 43 formed in an array are alternately arranged in a case where the distance between adjacent electrodes is large and a case where the distance is small. That is, the two transparent electrodes 43 having a large space
The transparent electrode lines of the transparent electrode 43a on the right side of FIG. 3 and the transparent electrode 43b on the left side of FIG. , Are arranged so as to have a positional relationship that coincides with the center of the image display element. On the other hand, a portion where the interval between the transparent electrodes 43 is narrow corresponds to a boundary portion between pixels.

The transparent electrode 44 located on the lower side of the paper of FIG. 3 (that is, the transparent electrode disposed on the upstream side of the optical path)
Shows a case in which it is formed on the entire surface of the transparent substrate 42, but may be formed as an array electrode having a symmetrical arrangement with the upper transparent electrode 43. Also, 46
Are liquid crystal molecules forming the liquid crystal layer 45.

FIG. 3A schematically shows a liquid crystal alignment state when the liquid crystal cell is not operating. That is,
When no voltage is applied to the transparent electrodes 43 and 44 and the liquid crystal cell is in an electric field-free state, the liquid crystal molecules 46 are subjected to a homogeneous alignment treatment so as to be parallel to the transparent substrates 41 and 42. . Here, in FIG.
The long axis of the liquid crystal molecules 46 is in the horizontal direction of the paper surface, that is, the transparent substrate 4.
It is assumed that an orientation process is performed so as to be in a direction parallel to 1,42. In such a state, no matter what part of the liquid crystal cell receives linearly polarized light having a polarization plane parallel to the paper surface (that is, image light emitted from the image display element 3), The light emitted from the liquid crystal cell (that is, deflected image light) is straightly emitted without any light path deflection.

FIG. 3B (hereinafter referred to as state α)
Is a case where a voltage equal to or higher than a threshold value is applied only to the transparent electrode 43a (hatched electrode) line disposed on the right side in the set of transparent electrodes 43 disposed on the upper side. Is shown. The liquid crystal molecules 46 arranged at the position of the transparent electrode 43a to which the voltage is applied
Is oriented in the vertical direction on the paper surface, that is, in a direction perpendicular to the transparent substrates 41 and 42 by rotating the major axis by 90 degrees due to the applied electric field, and is disposed at the position of the transparent electrode 43b where no voltage is applied. The liquid crystal molecules 46 remain oriented in the left-right direction on the paper plane, that is, in a direction parallel to the transparent substrates 41 and 42.

The distribution of the alignment direction of the liquid crystal molecules 46 caused by such a non-uniform electric field inside the liquid crystal cell is given by
A refractive index distribution for extraordinary light occurs. That is, when linearly polarized light having a polarization plane parallel to the paper surface (that is, image light emitted from the image display element 3) is incident, the liquid crystal molecules 4
As the major axis of 6 becomes perpendicular to the transparent substrates 41 and 42, the effective refractive index decreases, and the refractive index distribution is as shown by the solid line (that is, state α) shown in FIG. Therefore,
The set of transparent electrodes 43 (43a, 43a,
43b) The linearly polarized light incident on the center of the pixel arranged corresponding to the line is deflected to the left side of the paper as shown in FIG. 3B by the refraction effect due to the gradient of the refractive index. Thus, the light is emitted as deflected image light.

Next, FIG. 3C (hereinafter referred to as state β)
Is a case where a voltage equal to or higher than a threshold value is applied only to the transparent electrode 43b (hatched electrode) line disposed on the left side of the set of transparent electrodes 43 disposed on the upper side. Is shown. When the transparent electrode 43 to which a voltage is applied is switched from the transparent electrode 43a to the line of the transparent electrode 43b as in a state β shown in FIG.
The alignment state of the liquid crystal molecules 46 also changes, and the effective refractive index for linearly polarized light having a polarization plane parallel to the paper surface changes to a refractive index distribution as shown by a broken line (that is, state β) shown in FIG. . Therefore, the linearly polarized light incident on the center of the pixel disposed corresponding to the pair of transparent electrodes 43 (43a, 43b) in the state β is refracted by the gradient of the refractive index. As shown in FIG. 3 (C), the light is deflected in the opposite direction to the case of FIG.

The speed at which the linearly polarized light (that is, the image light from the image display element 3) incident on the optical path deflecting means 4 is changed from the state shown in FIG. 3B to the state shown in FIG. It is optimized by the physical properties of the liquid crystal material forming the liquid crystal layer 45 and the intensity of the applied electric field. In the pixel shift method used as an image display device, it is preferable that the time of the image sub-frame is 10 milliseconds or less, so that the response time is required to be several milliseconds or less. Here, when a nematic liquid crystal is used as the liquid crystal material, a high-speed response may be achieved by using a two-frequency driving method. However, when the two-frequency driving method is used, it is necessary to use, as the optical path deflection driving means 9, an electrode driving means capable of applying voltages having different driving frequencies to one transparent electrode 43 line. Not only the two-frequency driving method but also the optical path deflecting driving means 9 by some means is used to synchronize the state α with the driving timing of the image sub-frame to be displayed on the transmission type liquid crystal light valve forming the image display element 3. By switching the state β, an apparent pixel multiplying action on the screen 6 can be realized.

FIG. 5 shows a case where linearly polarized light emitted from the four pixels of the transmission type liquid crystal light valve forming the image display element 3 enters the liquid crystal cell forming the optical path deflecting means 4 shown in FIG. FIG. 3 is a schematic diagram showing an optical path of the liquid crystal cell when the light enters the liquid crystal cell from a lower side of the paper surface.

In FIG. 5, for example, in the first image sub-frame, four pixels of the transmissive liquid crystal light valve forming the image display element 3 are a, c, and c, respectively.
When the liquid crystal cell forming the optical path deflecting means 4 is in the state of e, g, the liquid crystal cell forming the optical path deflecting means 4 is in a state of the state α shown in FIG. 43
a, 43b), when a voltage equal to or higher than the threshold is applied only to the transparent electrode 43a line disposed on the right side, linearly polarized light (from the respective pixels of the transmissive liquid crystal light valve) is applied to the liquid crystal cell. That is, the image light) is deflected in the left direction on the paper surface and emitted as deflected image light.

In the second image sub-frame,
The four pixels of the transmissive liquid crystal light valve are switched to the states b, d, f, and h, respectively, and in synchronization with the switching, the liquid crystal cell is brought into the state β shown in FIG.
That is, in the pair of electrodes (43a, 43b) of the transparent electrode 43 arranged on the upper side, when switching to a state in which a voltage equal to or higher than the threshold is applied only to the line of the transparent electrode 43b arranged on the left side, Linearly polarized light (i.e., image light) incident from each pixel of the transmission type liquid crystal light valve with respect to the liquid crystal cell is deflected rightward on the paper,
It is emitted as deflected image light.

As shown in FIG. 5, when the linearly polarized light traveling obliquely in the liquid crystal cell is switched between the first and second image subframes at a period of several tens Hz to several hundreds Hz, the polarized image light is changed. When the light is emitted from the liquid crystal cell, eight pixels are apparently arranged as a, b, c, d, e, f, g, and h.
Note that an optical element may be provided downstream of the liquid crystal cell so that the deflected image light emitted from the liquid crystal cell is converted into parallel light parallel to the optical axis of the projection optical system.

FIG. 6 shows an optical path deflecting hand in an image display device.
It is a perspective view which shows the outline of the arrangement position of the step 4. Figure 6
The same parts as those in FIGS. 1 and 3 are denoted by the same reference numerals.
are doing. The arrow 3z indicates the output from the image display element 3.
Indicates the polarization direction of the linearly polarized light that is the emitted light (that is, image light).
The arrow 4z indicates a pixel deflected by the optical path deflecting unit 4.
Although the shift direction is shown, in the present embodiment, an arrow
The marks 3z and 4z are both in the left-right direction of the paper surface (that is,
(Horizontal direction). Also, 4o ₁Is
By the optical path deflecting means 4, one direction (that is, the left and right
Direction) shows the observed image when pixel multiplication is applied only to
You.

At least one of the transparent electrodes 43 constituting the optical path deflecting means 4 is located on the near side of the paper in the optical path deflecting means 4 shown in FIG. 6 (ie, on the downstream side of the optical path).
It is formed linearly in the vertical direction of the paper surface (that is, in the vertical direction of the screen). In the case where the image light emitted from the image display element 3 is linearly polarized light polarized in the horizontal direction 3z (that is, the horizontal direction of the screen) 3z on the paper surface, as described above, the entire optical path Is shifted in the horizontal direction (ie, the horizontal direction of the screen) 4z on the paper surface of FIG.
It can be emitted as deflected image light. Therefore, as described above, with a relatively simple configuration of the transparent electrode, it is possible to realize a high-definition image display device with high resolution in the horizontal direction, that is, the horizontal direction of the screen. (Claim 1
(Corresponding to the invention described in any one of (1) to (3))

It should be noted that, as shown in FIG.
In the case where only the direction of the optical path is deflected by the liquid crystal cell constituting the above, the pixel on the incident side is adjusted in accordance with the pixel size on the exit side (that is, the pixel size of the deflected image light emitted from the optical path deflecting unit 4). It is necessary to finely adjust the size (that is, the pixel size of the image light incident from the liquid crystal display element 3). As a method of adjusting the pixel size on the incident side, a method of restricting an optical path through a mask having an opening corresponding to a pixel position, a method of condensing light with a microlens array arranged corresponding to a pixel position, and the like are applied. You can also. However, the use of the mask reduces the light use efficiency, while providing a new microlens array leads to an increase in the cost of the image display device. Therefore, as another configuration example of the image display device according to the present invention, one liquid crystal cell has both the function of reducing the pixel size (light-collecting function) and the function of deflecting the optical path (pixel shifting function) simultaneously. A configuration is also possible.

Next, an example of the configuration of the light path deflecting means 4 having such a pixel reduction function and light path deflecting means will be described with reference to FIGS.
It will be described based on. FIG. 7 is a cross-sectional view showing another embodiment of the light path deflecting means 4 in the image display device according to the present invention, and schematically shows a liquid crystal light deflecting element having a pixel reduction function and a light path deflecting function. . The sectional view of the optical path deflecting means 4 shown in FIG. 7 is similar to the sectional view in FIG. FIG. FIG. 8 is a schematic diagram showing a refractive index distribution for linearly polarized light in the optical path deflecting means 4 shown in FIG.
The figure shows the positional relationship with the upper transparent electrode 43 (that is, the transparent electrode array disposed downstream of the optical path) of the liquid crystal cell forming the optical path deflecting means 4 and the refractive index distribution of the liquid crystal layer 45. It is shown schematically.

The basic structure relating to the material and processing method used for the liquid crystal cell shown in FIG. 7 may be the same as that of FIG. 3, and only the arrangement pitch and width of the transparent electrode array are changed. It is. 7, parts having the same functions as those in FIG. 3 are denoted by the same reference numerals.
That is, in FIG. 7, the transparent electrodes 4 are provided on the upper transparent substrate 41 at the same pitch as the pixel pitch of the pixels of the image display element 3 at positions corresponding to the boundaries between the pixels.
3 shows an example in which it is formed in an array. The electrode width of the transparent electrode 43 on the side facing the liquid crystal layer 45 is not particularly limited, but corresponds to the optical path deflection amount and the pixel reduction amount in the liquid crystal cell serving as the optical path deflecting unit 4. The inside of the liquid crystal cell is set to have a desired electric field intensity distribution.

As shown in FIG. 7A (hereinafter, referred to as state γ), the transparent electrode 43 is different from the case shown in FIG.
The lines are arranged at regular intervals and at equal intervals. In the transparent electrode 43 lines, a voltage equal to or higher than a threshold is applied to one of the alternately arranged transparent electrode 43c (hatched electrodes) lines. When the voltage is applied, as in the case described with reference to FIGS. 3 and 4, the alignment direction of the liquid crystal molecules 46 changes, and a refractive index distribution is generated in the liquid crystal layer 45. That is, when linearly polarized light having a polarization plane parallel to the paper surface (that is, image light emitted from the image display element 3) is incident, the major axis of the liquid crystal molecules 46 is oriented perpendicular to the transparent substrates 41 and 42. As, the effective refractive index decreases, and the refractive index distribution is as shown by the solid line (that is, state γ) shown in FIG.

However, since the interval between the transparent electrodes 43 to which a voltage is applied is larger than that in FIG. 3, a convex lens having a relatively large refractive index distribution and a relatively large pitch as shown by the solid line (ie, state γ) in FIG. (Ie, exhibit a convex lens effect). Therefore, the transparent electrode 43c shown in FIG.
(Hatched electrode) In the state γ in which a voltage higher than the threshold is applied to the line, the transparent electrodes 43c and 43
The linearly polarized light incident on the intermediate portion where d is arranged is refracted by the gradient of the refractive index (convex lens effect).
As shown in FIG. 7A, the light is alternately deflected in the left-right direction of the drawing toward the transparent electrode 43d to which no voltage is applied, and is condensed and emitted as deflected image light. It will be.

Next, FIG. 7B (hereinafter referred to as state δ)
Indicates a case where a voltage equal to or higher than the threshold is applied to the transparent electrode 43d (hatched electrode) line on the side different from that in FIG.
When the transparent electrode 43 to which the voltage is applied is switched from the transparent electrode 43c to the line of the transparent electrode 43d as in the state δ shown in FIG. The effective refractive index for linearly polarized light having an appropriate polarization plane changes into a refractive index distribution as shown by a broken line (that is, state δ) shown in FIG. Therefore, FIG.
A state in which a voltage equal to or higher than a threshold is applied to the transparent electrode 43d (hatched electrode) line shown in FIG.
In the case of (1), the linearly polarized light incident on the intermediate portion where the transparent electrodes 43c and 43d are arranged is converted into a transparent electrode to which no voltage is applied as shown in FIG. The light is alternately deflected in the left-right direction on the paper surface toward the 43c side, is condensed, and is emitted as deflected image light.

In the arrangement state of the transparent electrode 43 as described above, it is possible to give one convex lens effect to two pixels of the image display element 3, and to realize an optical path deflection function and image reduction with a simple element configuration. Another feature of the present invention is that the configuration is such that both functions can be realized at the same time.

Here, a diagram similar to the explanatory diagram shown in FIG. 5 is shown in FIG. 9, and the convex lens effect will be described in further detail. That is, FIG. 9 shows a case where the linearly polarized light emitted from the four pixels of the transmission type liquid crystal light valve forming the image display element 3 enters the liquid crystal cell forming the optical path deflecting means 4 shown in FIG. It is a schematic diagram showing an optical path,
The case where the light enters the liquid crystal cell from the lower side of the paper is shown.

In the present embodiment, the size of the pixel on the incident side which enters the liquid crystal cell forming the optical path deflecting means 4 is set to be relatively large as compared with the case of FIG. Therefore, for example, in the first image sub-frame, when the liquid crystal cell is in the state γ shown in FIG.
When the four pixels of the transmissive liquid crystal light valve forming the image display element 3 display the states of a, c, e, and g, respectively, the solid line in FIG. 8 (that is, the state γ) shows the refractive index distribution. As shown in FIG. 9, the emission side pixel of the liquid crystal cell (that is, the pixel of the deflection image light emitted from the liquid crystal cell)
Means that a and c and e and g are deflected in the directions approaching each other, and are condensed and reduced at the same time. That is, in such a case, due to the refractive index distribution, the pixel is displayed at the position of the emission-side pixel indicated by the solid line in the upper part of FIG. However, the pixel pitch of the emission-side pixels is not constant, and narrow and wide intervals are alternately arranged.

Next, in accordance with the display timing of the second image sub-frame, the liquid crystal cell changes the transparent electrode 43 to which a voltage is applied from the transparent electrode 43c to the transparent electrode 43c as shown in a state δ shown in FIG. 7B. When switching to 43d, the refractive index distribution switches as shown by the broken line in FIG. 8 (that is, state δ).
Here, in synchronization with the switching, four pixels of the transmissive liquid crystal light valve forming the image display element 3 display the states of b, d, f, and h, respectively, as a second image sub-frame. 7A, the reduced pixel moves from the case of FIG. 7A to the position of the emission side pixel indicated by the broken line in the upper part of FIG.

The first and second image subframes are several tens of H
By switching from z to several hundred Hz, when the liquid crystal cell is emitted as deflected image light, apparently,
Eight pixels that are irregularly arranged as b, a, c, d, f, e, g, and h are formed. In addition, the display image due to such an irregular arrangement of the pixel shift is
On the image display element 3, the data of the subfield image is corrected and displayed in advance by the display driving means 8 so that the image is formed as a normal image.

With the configuration described above, the pixel reduction effect as a light condensing effect by the liquid crystal lens effect and the pixel shift effect by switching the liquid crystal lens formation position can be simultaneously achieved by using a very simple transparent electrode configuration. One liquid crystal cell can achieve both. Therefore, the optical path deflecting means having the light condensing function can be configured with a simple element configuration, so that a bright and high-definition image display can be performed at low cost and at the same time preventing a decrease in light use efficiency. (Corresponding to the invention described in claim 4)

In the configuration of the optical path deflecting means 4 as shown in FIG. 7 or FIG. Therefore, the pixel size of the emitted deflection image light changes depending on the emission side position of the liquid crystal cell constituting the optical path deflecting unit 4. For example, without using any projection optical system, on the emission side of the liquid crystal cell, a diffuser or the like is arranged, such as when directly observing an image, if the position of the liquid crystal cell and the diffuser is shifted, The apparent pixel size will change. Therefore, it is desirable that the deflected image light emitted from the liquid crystal cell is parallel light parallel to the optical axis. Also, when using an enlargement optical system, from the viewpoint of the design of the lens system, similarly,
It is preferable that the deflected image light emitted from the liquid crystal cell is parallel light.

Therefore, as still another configuration example of the present invention,
A case where an optical element is provided so that the deflected image light emitted from the liquid crystal cell is parallel to the optical axis of the projection optical system will be described next with reference to FIG. FIG.
In the optical path deflecting means 4 shown in FIG.
FIG. 3 is a schematic view showing an embodiment in which a light beam collimating means is provided on the emission side of the light beam.
An example is shown in which the deflected image light emitted from the optical path deflecting means is made parallel by using a concave lens array.

That is, when the characteristics of the liquid crystal lens array forming the optical path deflecting means 4 have a convex lens effect as shown in FIG. It is preferable that the concave lens array be configured to return the optical path of the deflected image light emitted from the cell to parallel light. Therefore, for example, as shown in FIG. 10, as the light beam collimating means 49, the concave lens array is equal to the pixel pitch on the incident side and is shifted by half a pixel from the pixel position on the incident side of the optical path deflecting means. 9 (that is, the position where the central axis of each concave lens is arranged at the boundary between the pixels on the incident side).
The non-parallel outgoing light (ie, deflected pixel light) as shown in
By the light beam collimating means 49, it is possible to obtain outgoing light parallel to the optical axis (that is, parallelized polarized image light) in all pixels.

By arranging the liquid crystal cell shown in FIG. 10 at the same arrangement position as that shown in FIG. 6, the image light emitted from the image display element 3 can be shifted in the left-right direction with respect to the plane of the paper (ie, on the screen). In the case of the linearly polarized light in the horizontal direction, the entire image display element 3 is uniformly pixel-shifted and condensed in the horizontal direction of the paper surface (that is, the horizontal direction of the screen), and the emitted light (that is, the collected light). (Parallel light beam). Therefore, as described above, with a relatively simple transparent electrode configuration, a high-resolution image display device with high resolution in the horizontal direction, that is, in the horizontal direction of the screen, high light use efficiency, and high pixel position accuracy can be realized. Can be realized.
(Corresponding to the invention described in claim 5)

Next, another embodiment of the optical path deflecting means in the image display device according to the present invention will be described with reference to FIGS. Here, FIG.
FIG. 12 is a cross-sectional view showing a configuration in which both upper and lower transparent electrodes in the optical path deflecting means are arranged in an array.
12 is a cross-sectional view illustrating a configuration in which an auxiliary transparent electrode array is further added to the optical path deflecting unit illustrated in FIG.

In the liquid crystal cell forming the optical path deflecting means 4 shown in FIGS. 3 and 7, the upper side (ie, the downstream side of the optical path) is used.
The transparent electrode 4 disposed on the transparent substrate 41 located at
3, only the transparent electrodes 43 and 44 disposed on the upper and lower transparent substrates 41 and 42, respectively, are formed in an array as shown in FIG. Is also good. In such a case, the transparent substrates 41, 42 of the upper and lower transparent electrodes 43, 44 are arranged.
It is desirable to make adjustments so that the above arrangement positions match.

Further, in order to adjust the electric field distribution in the liquid crystal layer 45, a voltage can be supplementarily applied by further adding an array of auxiliary transparent electrodes 47 as shown by hatching in FIG. Means may be provided. FIG. 12 shows a case where one array of the auxiliary transparent electrodes 47 is added to one pixel at a time. Alternatively, a configuration may be employed in which a plurality of auxiliary transparent electrodes 47 are added to change the applied voltage stepwise.

In the configuration of each optical path deflecting means described above, one liquid crystal cell is used, and pixel multiplication is performed only in one direction (in each of the above-described embodiments, for example, the horizontal direction of the paper shown in FIG. 6). , Ie, pixel multiplication only in the horizontal direction of the screen)
However, in order to display a higher-definition image, it is necessary to perform pixel multiplication in the vertical and horizontal directions, that is, in the horizontal and vertical directions of the screen.

Next, with reference to FIGS. 13 and 14, an example of the configuration of an image display device in the case where pixel multiplication is performed in the vertical and horizontal directions will be described. Here, FIG. 13 is a schematic configuration diagram showing an outline of still another configuration example in the image display device according to the present invention. Is shown. FIG.
FIG. 4 is a perspective view schematically showing an arrangement position of the optical path deflecting means 4 shown in FIG. The optical path deflecting means 4 shown in FIG. 13 has means for deflecting the optical path in two vertical and horizontal directions perpendicular to each other. One optical path deflecting means 4a
And a second optical path deflecting unit 4c for deflecting in the vertical direction of the paper surface (that is, the vertical direction of the screen on the screen 6).

That is, as shown in the perspective view of FIG. 14, the first optical path deflecting means 4a for deflecting the optical path in the horizontal direction of the paper surface (ie, the horizontal direction of the screen) is arranged on the upstream side of the optical path. A second optical path deflecting means 4c for deflecting the light in the vertical direction of the screen is disposed downstream of the optical path;
Furthermore, between the first and second optical path deflecting means 4a, 4c,
A plane of polarization rotation means 4b for rotating the plane of polarization of the linearly polarized light incident thereon is provided.

The first and second optical path polarizing means 4a,
The internal configuration of 4c is the same as the configuration of the optical path deflecting means 4 using any one of the liquid crystal cells shown in FIG. 3, FIG. 7, FIG. 11, or FIG. Further, the directions of deflection by the respective optical path deflecting means 4a and 4c are arranged so as to correspond to the two directions of the pixel array of the image display elements 3 arranged two-dimensionally. That is, in general, the directions of the pixel arrangement of the image display elements 3 are arranged so as to be orthogonal to each other in the vertical and horizontal directions, and therefore, as shown in FIG. 14, the first and second optical path deflecting means 4a and 4c. Of the first and second optical path deflecting means 4a, 4c so that the direction of action, that is, the optical path deflecting direction is also orthogonal to each other.
Four arrays (only the transparent electrode 43 on the downstream side of the optical path is shown in FIG. 14 and the transparent electrode 44 on the upstream side is not shown) and the direction of the alignment treatment of the liquid crystal layer (not shown in FIG. 14). Is set.

When a liquid crystal cell is used as the light path deflecting means 4a, 4c, the direction of the linearly polarized light that is incident on the light path deflecting means 4a, 4c matches the direction in which the light path of the incident light is deflected. Therefore, the polarization plane rotating means 4b is provided between the two optical path deflecting means 4a and 4c as described above. In the polarization plane rotating means 4b, the light is rotated until the linear polarization direction of the light emitted from the first optical path deflecting means 4a matches the optical path deflecting direction of the second optical path deflecting means 4c (90 degrees in the present embodiment). After that, the light enters the second optical path deflecting means 4c.

As a constituent material of the polarization plane rotating means 4b, a TN liquid crystal cell, a ferroelectric liquid crystal cell, a half-wave plate, a Faraday rotator, or the like can be used. When a ferroelectric liquid crystal cell is used, it is not necessary to perform switching by applying a voltage, and thus a transparent electrode may not be provided. However, it is necessary to optimize the alignment treatment of the transparent substrate surface and its directionality. . When a wavelength-dependent material such as a half-wave plate is used, the optical path may be once separated for each color of the incident light by a dichroic mirror or the like, and a half-wave plate for each color may be provided and combined again. good. Further, since the one-dimensional periodic sub-wavelength structure exhibits birefringence, a birefringent phase plate color-compensated can be produced by using this property. In a phase plate having a fine structure, the wavelength dependence of the phase difference can be canceled by using the strong wavelength dispersion characteristics of the structure. For example, in the case of ordinary dispersion in which the refractive index decreases as the wavelength increases, the degree of the wavelength dispersion greatly differs depending on the polarization direction. Therefore, by optimizing the periodic structure, a portion where the difference Δn in refractive index is proportional to the wavelength appears. Since the phase difference is inversely proportional to the wavelength, the wavelength dependence can be eliminated by canceling out that Δn is proportional to the wavelength.

As described above, the optical path deflecting means 4a and 4c for deflecting the optical path in two directions coincident with the pixel arrangement direction on the image display element 3 are provided. to, by providing a polarization plane rotating unit 4b, as the observed image 4o ₂ shown in FIG. 14, it is possible to display a high-definition image the number of pixels the apparent horizontal and vertical two directions perpendicular to each other has been multiplied. Therefore, it is not necessary to use a liquid crystal microlens having a circular hole-shaped electrode pattern as in the related art, and to adopt a complicated electrode configuration in which the optical path is deflected in two directions, that is, a relatively simple electrode configuration. By combining the elements, it is possible to realize optical path deflection (that is, pixel shift) in two vertical and horizontal directions.
(Corresponding to the invention described in claim 6)

Next, with respect to each embodiment of the image display apparatus according to the present invention, the results of various evaluation tests will be described with reference to more specific configuration examples.

(Evaluation Test Example 1) In the image display device shown in FIG. 1, a 0.9 inch XGA (1024 × 768 dot) polysilicon TF
Using a T liquid crystal panel, the pixel pitch is approximately 18μ both vertically and horizontally.
m, the aperture ratio of each pixel is about 50%. Also, a microlens array is provided on the light source side of the image display element 3,
The configuration is such that the light collection rate of the illumination light is increased.

Further, as the light source 1, LE of RGB three primary colors is used.
A so-called field-sequential system is adopted in which a D light source is used to perform color display by rapidly switching the color of illumination light applied to one of the polysilicon TFT liquid crystal panels forming the image display element 3 to perform color display. When the frame frequency of the image display is 60 Hz, one frame is generally further divided into three colors, so that the image corresponding to each color is switched at 180 Hz.

In accordance with the image display timing of each color of the polysilicon TFT liquid crystal panel, the L of the corresponding color is
By turning on / off the ED light source,
Apparently, a full-color image is displayed.
Since such a method can be constituted by one polysilicon TFT liquid crystal panel without using a color filter, it is advantageous for miniaturization of the device together with high definition of an image. Therefore, in this evaluation test example 1, the field sequential method and the pixel shift method are used in combination.

Here, in order to perform double pixel multiplication in the horizontal direction of the screen, it is necessary to shift the pixel position at a period of 120 Hz which is twice the frame frequency of image display. Display time of field image is 8.3
Within milliseconds. The display time includes a time required for switching the optical path (that is, an optical path switching time) Δt and a time during which the polysilicon TFT liquid crystal panel can be used for image display. On the other hand, the longer the time that can be used for image display, the longer the LED emission time of the field sequential method can be, so that the emission luminance of the LED can be reduced and the burden on the LED light source is reduced.

Therefore, it is preferable that the optical path switching time Δt is as short as possible, and high-speed optical path switching means is required. In the image display device shown in Evaluation Test Example 1, a dual frequency driving method of a nematic liquid crystal cell capable of switching at high speed with a switching time of 1 millisecond or less was adopted. As the optical path switching means capable of high-speed operation, in addition to the dual frequency driving method, a method of changing the inclination angle of the refraction plate using a swing mechanism such as a piezoelectric actuator is also possible, as described above. However, the use of such a swinging motion may cause vibration or noise, which is not preferable.

Next, the steps of manufacturing the liquid crystal microlens array forming the optical path deflecting means 4 will be described in detail. First, a thin glass substrate (3 cm x 4 cm, thickness of 0.
15mm), an ITO (Indium Tin Oxide) vapor-deposited film is etched, and the ITO having a width of 10 μm and an arrangement pitch of 18 μm is etched.
A transparent electrode line was formed. Next, alternately connected skewer electrodes were formed so that the same voltage could be alternately applied to the ITO transparent electrode lines. Further, of the glass substrate surface, on a surface side on which the ITO transparent electrode line is formed,
Spin coat a polyimide-based alignment material, and
m of alignment film was formed. Then, after the glass substrate was annealed, rubbing was performed in a direction perpendicular to the ITO transparent electrode lines.

The two glass substrates manufactured by the above manufacturing steps are vertically opposed with the ITO transparent electrode line forming surfaces facing each other, and an 8 μm-thick spacer member is sandwiched around the periphery of the glass substrate. In addition, the two transparent ITO electrode lines formed on the two glass substrates which are vertically opposed to each other are aligned and bonded so that the arrangement positions of the two ITO transparent electrode lines coincide with each other. A cell was prepared. Next, a nematic liquid crystal having a positive dielectric anisotropy was injected into the empty cell under normal pressure to produce a liquid crystal cell. Here, since the directions of the rubbing treatments applied to the upper and lower two glass substrates are the same, as shown in FIG.
Are all aligned in the same direction (in FIG. 3A, the long axes of the liquid crystal molecules 46 are aligned in the horizontal direction on the paper).

Next, the following verification test was performed to confirm the operation of the manufactured liquid crystal cell. That is, in an image display device, an opening width of 13 μm × 13 μm is simulated as a transmission type liquid crystal light valve to be arranged at a stage preceding the liquid crystal cell.
Corner openings, and the vertical and horizontal pitch of the openings is 18
A light-shielding mask having a thickness of μm was prepared, and the light-shielding mask was arranged on the incident side of the liquid crystal cell. Further, the alignment was performed so that the center of the opening of the light-shielding mask coincided with the center of the ITO transparent electrode line of the liquid crystal cell.

After that, when the liquid crystal cell was irradiated with parallel light vertically incident on the liquid crystal cell from the light shielding mask side, observation was made from the light emitting side of the liquid crystal cell. Was observed as it was, and it was confirmed that, when the liquid crystal cell was in an electric field-free state, incident parallel light was transmitted as it was.

Further, as shown in FIG. 7, when a voltage of about 3 V was applied to one of the alternate ITO transparent electrode lines, a liquid crystal lens as shown in FIG. The effect appeared. That is, when a diffusion plate having a thin diffusion layer was aligned on the emission side of the liquid crystal cell, and diffused light was observed on the emission surface of the liquid crystal cell,
The opening width of the opening of the light-shielding mask is 13 μm × 13 μm.
It is reduced from m square to about 4 μm × 13 μm, for example,
It was confirmed that the pixels were arranged at pixel positions as indicated by the solid lines of the emission-side pixels described in the upper part of FIG. Next, the ITO transparent electrode line to which a voltage is applied is switched, and the other I
When applied to the TO transparent electrode line, the reduced optical path (ie, from 13 μm × 13 μm square to about 4 μm × 13 μm)
It has been confirmed that the focal position of (opening width of) has moved and has been moved and arranged at the pixel position as shown by the broken line of the emission side pixel described in the upper part of FIG. Accordingly, it was confirmed that the liquid crystal cell was operating as a liquid crystal lens cell having a liquid crystal lens effect having both an image reduction effect (light condensing effect) and a pixel shift effect (optical path deflection effect).

Next, the liquid crystal lens cell having such a liquid crystal lens effect is disposed immediately after the transmission type liquid crystal light valve constituting the image display element, and the pixel position of the image display element and the ITO transparent electrode of the liquid crystal lens cell are arranged. The liquid crystal lens cell was manufactured by adjusting the positional relationship with the line so that the positional relationship was shifted by a half pixel as shown in FIG.

Thereafter, an observation experiment of black-and-white display using a transmission type liquid crystal light valve was performed using a small white lamp as a light source. That is, the transmission type liquid crystal light valve is
The liquid crystal cell was driven by the subfield image signal of Hz, and the voltage applied to the ITO transparent electrode line was alternately switched while the driving frequency of the voltage applied to the ITO transparent electrode line of the liquid crystal cell was switched in synchronization with the driving. That is, of the alternating ITO transparent electrode lines, a low frequency voltage of 200 Hz was applied to one transparent electrode line group, and a high frequency voltage of 100 KHz was alternately applied to the other transparent electrode line group. When the switching time of the liquid crystal lens cell was measured under these conditions, the switching time was 0.8 millisecond, and it was confirmed that high-speed switching as intended was possible.

In this evaluation test example 1, as shown in FIG. 9, since the shift direction of each pixel is not a common direction, the sub-field image of the transmissive liquid crystal light valve is corrected and driven. ing. When a diffuser having a thin diffusion layer is aligned with the exit side of the liquid crystal lens cell and diffused light on the exit surface of the liquid crystal lens cell is enlarged and observed, the pixel density in the horizontal direction, that is, the horizontal direction of the screen is twice as high. A fine display image was obtained.

(Evaluation Test Example 2) However, in the case of Evaluation Test Example 1, there was a case where a portion where the pixel size was non-uniform occurred near the image periphery. The cause of such non-uniformity is that the light emitted from the liquid crystal lens cell is not parallel light as a result of the non-uniform spacing between the light emitting surface of the liquid crystal lens cell and the diffusion plate. The pixel size on the diffusion plate is changed due to the condensing of the generated optical path. Then, next, an evaluation test was performed to make the light emitted from the liquid crystal lens cell (that is, deflected image light) parallel.

First, in the same manner as in Evaluation Test Example 1,
A liquid crystal lens cell was manufactured. Further, as shown in FIG. 10, a cylindrical micro concave lens array having a pitch of 18 μm equal to the pixel pitch on the incident side was provided on the exit surface of the manufactured liquid crystal lens cell. Further, as shown in FIG. 10, the concave lens array is placed at a position shifted by half a pixel from the incident side pixel position, and the light emitted from the concave lens array is uniform over the entire screen. The focal length of each concave lens of the concave lens array was adjusted so that the optical path shift amount was large. That is, the focal length of each concave lens is set so that the light emitted and condensed from the liquid crystal lens cell becomes parallel light, and the optical path deflecting means that can shift the optical path of the emitted light in the same direction. Was prepared.

After that, as in the case of the evaluation test example 1, the diffused light on the exit surface of the optical path deflecting means was directly and magnified using a diffusion plate, as in the case of the evaluation test example 1. In contrast, a high-definition image having a constant pixel size and a double pixel density in the horizontal direction could be observed over the entire screen.

(Evaluation Test Example 3) Next, an evaluation test in which pixel shift was performed in two directions in the vertical and horizontal directions was performed. First, in order to fabricate a polarization plane rotation element, a polyimide-based alignment material is spin-coated on a thin glass substrate (3 cm × 4 cm, 0.15 mm in thickness) to form an alignment film of about 0.1 μm. After the annealing treatment of the glass substrate, a rubbing treatment was performed. An 8 μm-thick spacer member is sandwiched between the two glass substrates produced in the above-mentioned production process, which are vertically opposed to each other. Produced a hollow cell. Then, in the empty cell,
A nematic liquid crystal having a positive value of dielectric anisotropy was injected with a material obtained by mixing an appropriate amount of a chiral material under normal pressure to produce a TN liquid crystal cell in which the orientation of liquid crystal molecules was twisted by 90 degrees. The TN
Since the liquid crystal cell has no electrode, it functions simply as a polarization plane rotation element.

Further, two optical path deflecting means (ie, liquid crystal lens cells) similar to those in the evaluation test example 2 were prepared, and the direction of the ITO transparent electrode line of the first optical path deflecting means and the ITO of the second optical path deflecting means were prepared. The direction of the transparent electrode line was arranged to be orthogonal to each other, and the polarization plane rotating element was arranged in the middle. Note that, of the two optical path deflecting units, the polarization plane of the light emitted from the first optical path deflecting unit disposed on the incident side of the illumination light coincides with the rubbing direction of the incident plane of the polarization plane rotating element (that is, the rubbing direction). The direction of the polarization plane rotating element is adjusted such that the direction of the transparent electrode line of the first optical path deflecting means is orthogonal to the rubbing direction of the incident plane of the polarization plane rotating element. Are interposed between the two optical path deflecting means.

In the optical system having such an arrangement, the light emitted from the second optical path deflecting means (that is, deflected image light) was directly observed on the diffusion plate in the same manner as in Evaluation Test Examples 1 and 2. In this evaluation test example 3, the pixel shift is performed in two directions in the vertical and horizontal directions. Even in such a case, the frequency of the applied voltage for performing the pixel shift in each of the vertical and horizontal directions is 120 Hz, and one direction. Is the same as in the case of the pixel shift. However, in Evaluation Test Example 3,
The phases in the vertical and horizontal directions are shifted by 90 degrees from each other,
The drive timing is set so that the pixels are shifted in the four directions. Therefore, the subfield image displayed on the image display element is rewritten at a cycle of 240 Hz, and a high-definition image in which the apparent number of pixels is multiplied by four in the vertical and horizontal directions can be displayed. No flicker was observed.

In the above evaluation test examples 1, 2, and 3, for example, each pixel of the image display element 3 shown in FIG.
Although the evaluation results obtained by observation directly or through a magnifying lens system are shown, exactly the same effects are obtained when observation is performed by projecting onto the screen 6 through the projection lens 5 of FIG.

[0116]

(Effects of the Invention According to any of Claims 1 to 3) A non-uniform electric field is formed in a liquid crystal layer instead of using a mechanical moving mechanism. Since the optical path of the incident light is deflected by the generated refractive index distribution in the liquid crystal layer, the position of the display pixel can be shifted at high speed, and the generation of vibration and noise can be suppressed. Further, even if an optical path deflecting element having a relatively simple structure similar to that of a normal liquid crystal display element is used, a high-definition image with an increased number of apparent pixels can be displayed.

(Operation and Effect of the Invention According to Claim 4) By alternately switching and applying a voltage to the transparent electrodes whose arrangement intervals are relatively wide, a lens-like (for example, convex lens-like) is formed in the liquid crystal layer. A liquid crystal microlens having a refractive index distribution and capable of electrically controlling the focal position of the lens is formed.Furthermore, since the voltage application position is alternately switched, the pixel of the image display element is The focus position (that is, the focus position) can be shifted while the light path of the image light is focused. That is, an efficient pixel reduction function and a pixel shift function can be compatible with one element (liquid crystal microlens).

Further, even when an image display element having a high aperture ratio but a large pixel pitch is used, high resolution can be realized by pixel multiplication without lowering the light use efficiency. Therefore, even if a relatively low-resolution image display element is used as it is, a bright and high-resolution image can be realized at low cost with a simple element configuration.

(Function and Effect of the Invention of Claim 5) The optical path of the light deflected and further condensed by the liquid crystal microlens according to the invention of claim 4 is set with respect to the optical axis. , Not parallel. Therefore, when the position accuracy of the optical device to which such a liquid crystal microlens is applied is poor, there is a possibility that the pixel size and the pixel pitch may not be constant for each pixel. However, as in the invention according to claim 5, the light condensed by the convex lens effect of the liquid crystal layer can be made parallel by the concave lens array arranged on the exit side of the liquid crystal microlens. In addition, the pixel size and the pixel pitch can be kept constant, and high-quality image display can be realized over the entire display image area.

(Function and Effect of the Invention According to Claim 6) By combining the optical path deflecting means for shifting the pixel in the horizontal direction of the image and the optical path deflecting means for shifting the pixel in the vertical direction, the two-dimensional direction can be obtained. Pixel multiplication is possible, but only with the combination of the two optical path deflecting means,
Since the linear polarization planes that can be deflected from each other are different, the pixel shift cannot be performed in the vertical and horizontal directions.
According to the sixth aspect of the present invention, a polarization plane rotating means is provided between the two optical path deflecting means, and the linear polarization plane of the light incident on the latter optical path deflecting means is changed to the latter optical path deflecting means. , The pixel shift in the two-dimensional direction can be surely performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an outline of a configuration example of an image display device according to the present invention.

FIG. 2 is a schematic diagram showing an example of apparent pixel doubling displayed on a screen.

FIG. 3 is a cross-sectional view of the liquid crystal cell when the liquid crystal cell serving as an optical path deflecting unit is cut along the optical axis.

FIG. 4 is a schematic diagram showing a refractive index distribution for linearly polarized light in the optical path deflecting unit shown in FIG.

FIG. 5 is a schematic diagram showing an optical path when linearly polarized light emitted from four pixels of a transmission type liquid crystal light valve forming an image display element enters a liquid crystal cell forming an optical path deflecting unit shown in FIG. 3; FIG.

FIG. 6 is a perspective view schematically showing an arrangement position of an optical path deflecting unit in the image display device.

FIG. 7 is a sectional view showing another embodiment of the optical path deflecting means in the image display device according to the present invention.

8 is a schematic diagram showing a refractive index distribution for linearly polarized light in the optical path deflecting means shown in FIG.

FIG. 9 is a schematic diagram showing an optical path when linearly polarized light emitted from four pixels of a transmission type liquid crystal light valve forming an image display element enters a liquid crystal cell forming an optical path deflecting unit shown in FIG. 7; FIG.

FIG. 10 is a schematic view showing an embodiment in which a light beam collimating means is provided on the exit side of the light path deflecting means in the light path deflecting means shown in FIG.

FIG. 11 is a cross-sectional view showing a configuration in which both upper and lower transparent electrodes in an optical path deflecting unit are arranged in an array.

12 is a cross-sectional view illustrating a configuration in which an auxiliary transparent electrode array is further added to the optical path deflecting unit illustrated in FIG.

FIG. 13 is a schematic configuration diagram showing an outline of still another configuration example in the image display device according to the present invention.

FIG. 14 is a perspective view schematically showing an arrangement position of an optical path deflecting unit shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Light source, 2 ... Illumination apparatus, 2a ... Diffusion plate, 2b ... Condenser lens, 3 ... Image display element, 3z ... Linear polarization direction, 4, 4a, 4c ... Optical path deflecting means, 4b ... Polarization plane rotating means, 4o ₁ , 4o ₂ … observation image, 4z… pixel shift direction, 5… projection lens, 6… screen, 7… light source drive unit, 8… display drive unit, 9… optical path deflection drive unit, 10
... image display control circuit, 41, 42 ... transparent substrate, 43, 4
4: transparent electrode, 45: liquid crystal layer, 46: liquid crystal molecule, 47:
Auxiliary transparent electrode, 49: Light flux collimating means.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/74 H04N 5/74 A (72) Inventor Ikuo Kato 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Kenji Kameyama 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Yasuyuki Takiguchi 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. F term (reference) 2H088 EA10 EA13 EA42 GA02 HA03 HA06 HA08 HA13 HA18 HA21 HA23 HA24 HA25 HA28 JA05 JA13 JA17 KA05 KA26 MA20 2H093 NA45 ND42 NE03 NE06 NF05 NF13 NF17 NG02 NG07 NG11 5C006 AF27 AF34 AF47 5C058 BA25 BB01 EA11 EA26 5C080 AA10 AA17 BB05 CC06 CC10 DD07 DD30 JJ01 JJ05 JJ06 KK07 KK43

Claims (6)

[Claims] 1. An image display device in which a plurality of pixels capable of controlling illumination light based on image information are two-dimensionally arranged, and an image field indicating a display time of the image information is further provided by a plurality of images. A display driving unit capable of temporally dividing the image display device into image sub-fields and driving the image display element; and a display driving unit for driving the image display element by the display driving unit for each image sub-field. By having an optical path deflecting means for deflecting an optical path, in an image display apparatus capable of multiplying and displaying an apparent number of pixels of the image display element, the optical path deflecting means has two transparent substrates and Having a transparent electrode disposed on each of the transparent substrates, and a liquid crystal layer interposed between the two transparent substrates, and including at least one of the transparent electrodes on the transparent substrate. The transparent electrodes provided are a transparent electrode array formed in an array at an arrangement pitch corresponding to the pixel pitch of the pixel, and the liquid crystal layer is formed of the transparent electrode array and the other transparent electrode. A liquid crystal layer capable of controlling the refractive index distribution by a voltage applied state between the transparent electrode and the transparent electrode on the substrate, and in synchronization with the display driving means, for each image subfield, the transparent electrode An image display device characterized by changing a voltage application state to an array. 2. The image display device according to claim 1, wherein at an arrangement pitch corresponding to a pixel pitch of the pixel,
The arrangement pitch of the transparent electrode array formed in an array is not limited to an interval that is one-to-one with the pixel pitch, but may be an integer multiple of the pixel pitch, or may be equal to a fraction of an integer. An image display device comprising: 3. The image display device according to claim 1, wherein the arrangement pitch of the transparent electrode array is a plurality of transparent electrodes as one set, and the arrangement pitch for each set of the transparent electrodes is set. An image display device comprising: 4. The image display device according to claim 1, wherein said optical path deflecting means is configured to apply a voltage to said transparent electrode array arranged at a predetermined arrangement pitch. A liquid crystal microlens array capable of condensing the image light incident from each pixel is formed, and a position of a transparent electrode to which a voltage is applied in the transparent electrode array is between adjacent transparent electrodes. An image display device wherein the focus position of the liquid crystal microlens array can be shifted and moved in time sequence along the arrangement direction of the transparent electrode array by being switched in time sequence. 5. A concave lens array according to claim 4, wherein said optical path deflecting unit can emit the light condensed by said liquid crystal microlens array as parallel light parallel to an optical axis. The light path deflecting means on the emission surface side. 6. The image display device according to claim 1, wherein the light is incident along a first pixel arrangement direction of the pixels with respect to a two-dimensional arrangement direction of the pixels. A first optical path deflecting means capable of deflecting an optical path of the coming image light and / or moving a focal position where the image light is condensed; and A second optical path deflecting means capable of deflecting an optical path of the image light incident through the first optical path deflecting means and / or moving a focal position where the image light is condensed. ,
Further, a polarization plane rotating means capable of rotating the direction of the polarization plane of the linearly polarized light from the first pixel arrangement direction to the second pixel arrangement direction includes the first optical path deflecting means and the second And an optical path deflecting means.