JP2001356411A - Image display device and graphic controller used for this image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an image display device to display images at a high speed and to realize high-quality images not to deteriorate durability in an image display device which observes small-sized image display elements having plural pixels capable of controlling illumination light according to image information as enlarged images enlarged by optical elements. SOLUTION: This device has a liquid crystal panel 4 which shifts the image display elements in correspondence to plural sub-fields constituting an image field in the about arraying surface direction of the elements and consists of a piezoelectric element 7 and a piezoelectric element drive section 12, i.e., a shift means for the image display elements. The time required for the image display element shift is set shorter than the time required for pixel switching and the image display element shift is allowed to be completed during the time from the start of the pixel switching before the end thereof. The piezoelectric element 7 is used for the image display element shift means and the pixel switching is performed in the period when the switching is not subjected to the acceleration acting during the image display element shift.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display apparatus for observing a small image display element having a plurality of pixels capable of controlling illumination light according to image information as an enlarged image using a lens.

[0002]

2. Description of the Related Art As an image display apparatus for observing a small image display element having a plurality of pixels whose light can be controlled in accordance with image information as an image enlarged by a lens, a front projector, a rear projector, a head mounted display, and the like are known. Widely used under the trade name. As the image display device, a CRT, a liquid crystal panel, a DMD (trade name: Texas Instrument Co., USA) and the like are used as products, and an inorganic EL, an inorganic LED, an organic LED, and the like are also being studied. . In addition, as an image display device that observes a small image display element at an equal magnification instead of observing it as an image enlarged by a lens, the above-described CR is used.
In addition to T, liquid crystal panel, inorganic EL, inorganic LED, organic LED, plasma display, fluorescent display tube, etc. are used as products, and FED (field emission display), PALC (plasma addressing display), etc. are also studied. ing. These are broadly classified into two types, a self-luminous type and a spatial light modulator type, each of which has a plurality of pixels capable of controlling light.

A problem common to these image display devices is to increase the resolution, that is, to increase the number of pixels, and to use an HDTV of about 1000 scanning lines for broadcast display.
Scan line 2000 for high resolution display of a workstation computer is already commercialized.
About this developed product has been announced by using a liquid crystal panel technology (2048 QSXGA by IBM Japan at the '98 Flat Panel Display Exhibition, 2400 QUXGA by Toshiba at the '99 Electronic Display Exhibition, etc.). However, increasing the number of pixels decreases the yield of the liquid crystal panel, decreases the aperture ratio, and increases the cost, decreases the brightness and contrast, and increases the power consumption. Was.

A conventional method of increasing the number of pixels by a factor of two or more using a plurality of image display elements is disclosed in Japanese Patent Laid-Open No. 3-150.
525 and JP-A-4-267290. In these, a plurality of image display elements which are shifted from each other are optically arranged, and a pixel of another image display element is arranged in a gap between the pixels of the image display element. However, in these, it is difficult to align a plurality of pixels, and the cost is increased because a plurality of image display elements are used, and a large projection lens is required.

To solve these problems, Japanese Patent Application Laid-Open No. 4-113
Japanese Patent Application Publication No. 308, Japanese Patent Application Laid-Open No. 5-289004, Japanese Patent Application Laid-Open No. 6-324320, and the like disclose an image display apparatus that performs interlaced display having twice the number of pixels using a single image display element. ing. Also, JP-A-7-365
Japanese Patent Application Laid-Open No. 04-2004 discloses a display device having four or more times the number of pixels using a single image display element. The combination of the member exhibiting the electro-optic effect and the birefringent crystal used by these uses the same means as the deflecting means conventionally used as the light distribution and optical switch in the optical communication field, and is already known. Technology. Also, JP-A-6-3
No. 24320 discloses, other than a combination of a member exhibiting an electro-optic effect and a birefringent crystal, as means for changing an optical path, means for shifting a lens, a vari-angle prism, a rotating mirror, a rotating glass, and the like. Japanese Patent Application Laid-Open No. 7-104278 discloses a means for moving a wedge prism.

FIG. 14 shows a conventional display method described in JP-A-6-324320, in which the resolution of an image display element is increased by a method of shifting a lens, and a virtual image enlarged by a lens is displayed. What you observe.
In FIG. 14, reference numeral 51 denotes an image display LCD panel;
Is an LCD drive circuit, 53 is an optical path changing means, and 54 is a voice coil drive circuit. Light path changing means 53
Is an eyepiece 53a, a lens mount 53b, and
It is composed of a voice coil 53c. Voice coil 53c
Are driven by a drive circuit 54, and the drive circuit 54
Is a signal O / for discriminating the odd field and the even field of the color video signal input from the LCD drive circuit 52.
E, the current flowing through the voice coil 53c is controlled, and the position of the LCD panel 51 is optically
The shift is made in the direction perpendicular to the optical axis of 3a.

The driving system for shifting or reciprocating the eyepiece 53a is not limited to the voice coil 53c, but a piezoelectric element, a bimorph, a step motor, a solenoid coil and the like are described in JP-A-6-324320. I have. As a method of changing the optical path, in addition to a method of shifting a lens or an optical member, a method of inserting an optical member, a method of rotating an optical member, a method of rotating a mirror, an active prism, an electro-optical element, and birefringence. A method using materials and the like are described.

FIG. 15 also shows Japanese Patent Application Laid-Open No. 6-324320.
This discloses a conventional display method described in Japanese Patent Application Laid-Open Publication No. H11-260, in which the resolution of an image display element is increased by a method using an electro-optical element and a birefringent material, and a virtual image enlarged by a lens is observed. In FIG. 15, reference numeral 61 denotes a polarization plane rotating member serving as an electro-optical element, and reference numeral 62 denotes a birefringent plate. The polarization plane rotating member 61 is formed by forming transparent electrodes 64 and 65 on both surfaces of a liquid crystal plate 63. A liquid crystal driving voltage is applied between the transparent electrodes 64 and 65 from a liquid crystal drive circuit 66. The polarization plane is rotated and deflected for each of the even and odd fields so that the polarization plane of the birefringent plate 62 matches the polarization plane of the normal light and the abnormal light. The normal light and the extraordinary light are
The amount of deflection changes due to the difference in the refractive index of the birefringent material.

However, such a method is a means for changing the optical path by shifting or deflecting the optical axis of the magnifying optical system, even if other means are used instead of the lens shifting means. Means for changing the optical path exist between the image display element and the magnifying optical system.
For this reason, when performing high-resolution display, the optical path length changes, or the off-axis of the lens is used as the optical axis of the entire optical system. Not only is the design and layout difficult, but one pixel of the microscopic image display element
In some cases, it is not possible to enlarge the image using the nsfer function. Also,
The non-uniformity of the member that changes the optical path itself may reduce the MTF. Further, when an electro-optical element is used, since the wavelength is not a single wavelength like a laser, there is a problem that a color shift of a phase occurs depending on the wavelength, and the contrast is greatly reduced.

Further, in such a conventional method, when an element having a low response speed is used as an image display element, the writing start time greatly differs between the first scan line and the last scan line in the same image field. Therefore, when a high scanning linear velocity is required, such as in a moving image, it is difficult to form a uniform change of the optical path in the scanning direction, and the contrast tends to decrease. With respect to a method for solving such a problem, Japanese Patent Application Laid-Open No. Hei 6-324320 discloses a method of dividing an electro-optical element into a plurality of parts in a scanning line direction, and Japanese Patent Application Laid-Open Nos. 11-296135 and 11-2.
No. 59039 also discloses a method for improving such a problem.

FIG. 16 shows the conventional improvement method described in Japanese Patent Application Laid-Open No. 6-324320, in which the influence of the difference in the writing time between the first scan line and the last scan line is reduced. This shows a method of causing the above. In FIG. 16, reference numeral 63 denotes a liquid crystal plate as a polarization plane rotating element. Instead of the transparent electrode 64 of FIG. 15, a plurality of scanning line transparent electrodes TD corresponding to the scanning lines are used to form the liquid crystal plate 63. The liquid crystal panel 63 is divided into a plurality of parts in a direction parallel to the scanning lines, and synchronized with the scanning of the liquid crystal for image display.
Are sequentially scanned to make the rotation state of the first and last polarization planes of the scanning line for image display uniform.

However, the cost of the conventional method or device increases because the structure of the element and the driving method are complicated. Further, it has not been possible to completely eliminate the non-uniformity in the scanning line direction. That is, in a current image display device having a large number of data scanning lines, when displaying a full-color moving image, the response speed of the display device cannot correspond to the speed of writing data in the direction of the scanning lines. In full color display,
Since gradation display of 64 gradations to 256 gradations is required for each color of RGB, analog modulation of normal TN liquid crystal, a combination of dither modulation and pulse width modulation for high-speed FLC, and the like are used. I have. However, for a display with a large number of pixels, the cost increases due to an increase in the defect rate and a decrease in the aperture ratio due to an increase in the absolute number of TFT elements, or a limitation on the response speed of the FLC and the driving method. Or a sufficient number of pixels or image quality is not obtained.

On the other hand, in a display device for performing digital gradation display by modulating the light intensity of illumination light, a spatial light modulator for obtaining high luminance is disclosed in Japanese Patent Laid-Open No. 11-75.
No. 144 discloses a conventional modulation method. In the modulation method, a first memory and a second memory are provided in an optical spatial modulation element, image data is transferred from the first memory in which image data is written to the second memory, and the transferred second memory is The state of the pixel is changed based on the image data. By using such a method, the effective illumination time of the illumination light to the optical spatial modulation element can be increased, so that an image display with low cost and high energy saving can be performed. However, such an optical spatial modulation device does not require a neutralization condition for canceling out a DC component of a liquid crystal in order to reduce a bit plane time when performing digital gradation display, and prevents deterioration of a liquid layer. The purpose is to realize a driving method that can
Furthermore, it aims at high-brightness, low-cost field sequential display due to an increase in light source utilization efficiency, and there is no spatial crosstalk in an image when the image display element according to the present invention is mutated in an image field. I'm not paying attention.

Further, in the conventional method of driving the means for changing the optical path from the image information signal to increase the resolution, the displacement of the real image or the virtual image by the magnifying optical system causes the dimensional variation of each of the resolution improving means. Also affected by variations in the initial assembly alignment. In addition, the mounting position may be displaced due to vibrations during use, and pixels that are originally displaced and located at different display positions may overlap or cause color misregistration, and the image may be displaced. Quality may degrade.

On the other hand, the applicant of the present invention has proposed a small-sized image forming apparatus having a plurality of pixels capable of controlling light in accordance with image information in order to provide a higher-resolution enlarged image which does not deteriorate optical characteristics of the magnifying optical system. An image display device for observing an image display element as an enlarged image using an optical element, and displaying an image in a direction substantially corresponding to a plane of arrangement of pixels corresponding to a plurality of subfields constituting an image field In an image display device having means for shifting or displacing the optically effective position of the element, the means for shifting the optically effective position is constituted by an image display element shift means comprising a piezoelectric element. An image display device featuring the feature is proposed. Furthermore, by providing illumination light control means for making illumination light having a different intensity profile of illumination light among a plurality of frames constituting a subfield corresponding to the displaced position, each subfield corresponding to the displaced position is provided. Has proposed an image display device capable of giving a high-resolution enlarged image with high gradation.

[0016]

However, although the above-mentioned image display device proposed by the present applicant can obtain a high-resolution enlarged image as described above, the time required for shifting the image display element and the time required for pixel switching are reduced. Since the operation timing is not sufficiently managed, there is a possibility that a time delay with respect to the image display may occur, and it is necessary to reduce the delay (claims 1 and 2).

Further, there is a problem that the image display element is constantly shifted during the operation of the apparatus. That is, the composition of the image display element material tends to change due to the acceleration applied to the image display element at the time of the shift, which is a factor of deteriorating the durability. There has been no means disclosed for improving such a deterioration factor, and there is a need for improvement (claims 2 and 3).

On the other hand, when attention is paid to an input image signal,
At present, the number of display pixels is variously set according to the input image signal. For example, when an image signal from a personal computer (hereinafter referred to as a personal computer) to a personal computer monitor is taken as an example, in a so-called AT compatible machine, 640 × in a VGA mode developed by IBM Corporation is used.
480 dots, 800 × 600 in SVGA mode
Dots, 1024 × 768 dots in the XGA mode, and the like. In the future, higher resolution images will be required,
It is expected that the resolution is also set variously depending on the application. In a conventional image display device, by setting a plurality of image display element shift positions, it is possible to display an image with more than the number of pixels of the image display element, but an appropriate image display means corresponding to an input image signal There is no disclosure regarding the above, and improvement is desired (problems of claims 4 and 6).

Further, there has been no prior disclosure of an image display element shift procedure for reducing abrasion deterioration accompanying the image display element shift and improving durability (claim 5).

Further, a color display method suitable for forming one image field by a plurality of sub-fields as an image display method when displaying a color image on an image display device is disclosed as specific means. There was no prior art (the problems of claims 7 and 8).

Further, there has not been disclosed any image display material and an appropriate driving method suitable for an image display device which solves the above-mentioned problems (the problems of claims 9, 10 and 11).

[0022]

In order to solve the above-mentioned problems, an invention according to claim 1 is an enlargement in which a small image display element having a plurality of pixels capable of controlling irradiation light according to image information is enlarged by an optical element. An image display device for observing as an image, and an image display element shift means comprising a piezoelectric element for shifting the image display element in a direction substantially corresponding to a plane in which pixels are arranged corresponding to a plurality of subfields constituting an image field. Wherein the image display element shift means sets the time required for shifting the image display element to be shorter than the time required for switching the pixels, and between the start and end of switching of the pixels. The timing of completing the shift of the image display element is set in the image display device.

According to a second aspect of the present invention, there is provided an image display apparatus for observing a small image display element having a plurality of pixels capable of controlling irradiation light in accordance with image information as an enlarged image obtained by enlarging an optical element. In an image display apparatus having an image display element shift unit composed of a piezoelectric element, the image display element is shifted in a direction substantially corresponding to a plane in which pixels are arranged in correspondence with a plurality of subfields constituting a field. The time required for shifting the image display element is set longer than the time required for switching the pixel, and the timing for completing the switching of the pixel is set between the start and end of the shift of the image display element. An image display device is provided.

According to a third aspect of the present invention, there is provided an image display apparatus for observing a small image display element having a plurality of pixels capable of controlling irradiation light in accordance with image information as an enlarged image enlarged by an optical element. In an image display apparatus having an image display element shift unit composed of a piezoelectric element, the image display element is shifted in a direction substantially corresponding to a plane in which pixels are arranged in correspondence with a plurality of subfields constituting a field. An image characterized by setting the switching operation of the pixels for displaying the image of the corresponding subfield to be completed before the shift of the image display element is started or to be started after the shift is completed. A display device is provided.

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the horizontal and vertical position setting of the image display element is performed based on the horizontal and vertical pixel number information in the input image information. An image display device comprising: a position setting number calculating means for automatically calculating the number; and a shift control means for setting a shift order and a shift amount of the image display element based on the position setting number. Provides the graphic controller used.

According to a fifth aspect of the present invention, in the invention of the fourth aspect, the presence or absence of the shift operation, the shift order during the shift operation, and the setting of the shift amount are determined in advance or the number of times of the shift. There is provided a graphic controller used in an image display device, which is automatically switched for each elapsed time.

According to a sixth aspect of the present invention, there is provided an image display apparatus for observing a small image display element having a plurality of pixels capable of controlling illumination light in accordance with image information as an enlarged image obtained by enlarging an optical element. In an image display device capable of shifting the image display element in the direction of a substantially array surface of pixels corresponding to a plurality of subfields constituting a field, the pixel aperture ratio or the pixel aperture shape is automatically or manually changed. An image display device having a pixel aperture ratio setting means is provided.

The invention of claim 7 is the invention of claim 1 or 2 or 3
Or an image display device for observing a small image display element having a plurality of pixels capable of controlling illumination light in accordance with image information as an enlarged image enlarged by an optical element, and constituting an image field. In an image display apparatus having an image display element shift unit composed of a piezoelectric element, the image display element is displaced in a direction substantially corresponding to a plane in which pixels are arranged corresponding to a plurality of subfields. And illumination light control means for controlling illumination so as not to be performed at the time of switching between the subfields, wherein illumination having different illumination light wavelength spectra and illumination light intensity profiles is performed for each time-division frame. Is provided.

The invention of claim 8 is the invention of claim 1 or 2 or 3
Or an image display device for observing a small image display element having a plurality of pixels capable of controlling illumination light in accordance with image information as an enlarged image enlarged by an optical element, and constituting an image field. A plurality of subfields constituting one image field in an image display device having an image display element shift unit composed of a piezoelectric element for displacing the image display element in a direction substantially corresponding to a plane in which pixels are arranged corresponding to the plurality of subfields Is repeatedly scanned several times, and illumination with different illumination light wavelength spectrum and illumination light intensity profile is performed for each scan, and illumination is controlled such that no illumination is performed when the subfield is switched. An image display device characterized by having means is provided.

[0030] The invention of claim 9 is the invention of claim 1 or 2 or 3.
Alternatively, in the invention of 6 or 7 or 8, the plurality of pixels for controlling the illumination light of the image display element are made of a ferroelectric liquid crystal material, and the reflection and the incidence of the illumination light to the image display element are performed through the same surface. An image display device having a mold structure is provided.

According to a tenth aspect of the present invention, in the ninth aspect of the present invention, when the display image is changed corresponding to a temporally continuous subfield or a continuous time division frame,
Provided is an image display device comprising: a pixel state control unit that performs a pixel switching operation only on a pixel whose display state needs to be changed, and maintains a current state of a pixel that does not need to change the display state. ing.

According to an eleventh aspect of the present invention, in the ninth or tenth aspect, it is necessary to change a display state when a display image is changed corresponding to a temporally continuous subfield or a continuous time-division frame. The present invention provides an image display device characterized in that when a pixel switching operation is performed on a certain pixel, an operation for relaxing the polarization of the pixel is performed immediately before the pixel switching operation.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image display device according to the present invention will be described below in detail with reference to the drawings. First, FIG. 1 is a schematic diagram illustrating an example of a configuration of an image display device to which the present invention is applied. In FIG. 1, 1 is a red LE
An illumination light source in which D is arranged in a two-dimensional array, 2 is a diffuser,
Reference numeral 3 denotes a condenser lens, 4 denotes a liquid crystal panel, 5 denotes a projection lens, 6 denotes a screen, 10 denotes a light source drive unit, and 11 denotes a liquid crystal panel drive unit. The illumination light emitted from the illumination light source 1 under the control of the light source drive unit 10
The illumination light becomes uniform by the condenser lens 3
Is controlled by the liquid crystal drive section 11 in synchronization with the illumination light source, and the liquid crystal panel 4 is critically illuminated. The illumination light spatially modulated by the liquid crystal panel 4 is enlarged by the projection lens 5 and projected on the screen 6. The liquid crystal panel 4 is vertically connected to a support 9, and the support 9 is fixed to a small piezoelectric element 7 having a piezo effect, and the piezoelectric element 7 is controlled by a piezoelectric element drive unit 12. . Although not shown, the liquid crystal panel 4 is also connected to a support fixed to the piezoelectric element in a direction perpendicular to the plane of the drawing.
The piezoelectric element is controlled by the piezoelectric element drive unit 12 so as to be displaced in the front-rear direction of the paper as in the vertical direction. Further, the liquid crystal panel 4, the support 9 and the piezoelectric element 7
Form a liquid crystal panel unit 8.

In FIG. 1, the liquid crystal panel 4 is driven by the piezoelectric element drive unit 12 so that the liquid crystal panel 4 has a pixel pitch of 1 at the pixel pitch in the up-down direction and the front-back direction, ie, in the x-axis and y-axis directions.
/ 2 (1 subfield) as one basic unit,
One pixel (one field) moves while being divided into four subfields. The time required for such movement is a time at which flicker perceived on the image of the liquid crystal panel 4 on the enlarged screen 6 is equal to or less than a practical level. By realizing such a movement time, image data corresponding to the moved position is displayed on the image display device for the subfield corresponding to the displaced position of the liquid crystal panel 4, whereby the 4
Image display with twice the number of pixels can be performed.

FIG. 2 is a diagram showing one embodiment of the liquid crystal panel unit 8 shown in FIG. 1, and is a schematic diagram viewed from the right in FIG. In FIG. 2, 7 'and 9' are
FIG. 1 shows a piezoelectric element and a support which are not shown in the drawing and are perpendicular to the plane of the drawing. In FIG. 2, for example,
The position of the liquid crystal panel 4 in the liquid crystal panel unit 8 is displaced by giving a displacement value Δx13 that becomes the position x1 → x0 in the x-axis direction and a displacement value Δy14 that becomes the position y1 → y0 in the y-axis direction (ie, Shift).

FIG. 3 shows a pixel (4 × 4) of the liquid crystal panel 4.
4 is a schematic diagram showing an enlarged view of (actual pixels of the liquid crystal panel No. 4). The pixel pitch is in the x-axis direction, y
When 2Δx and 2Δy are respectively provided in the axial direction, Δx and Δy corresponding to a half pitch of the pixel pitch are set as displacement values of one subfield, so that one real pixel of the liquid crystal panel 4 is quadrupled. It can be displayed as four pixels. In FIG. 3, (x0, y0) =
When an actual pixel having an aperture ratio of about 12% in the case of (0, 0) is provided, (x0, y0)
= (0,0), (Δx, 0), (0, Δy),
By setting (Δx, Δy), 15d, 1
Pixels can be displayed at the positions of 5b and 15c.

The pitch between the subfields need not be limited to 1/2 of the actual pixel pitch in both the x-axis and the y-axis.
It is possible to display nine times as many pixels, or to display twice as many pixels in the y-axis direction as の of the actual pixel pitch and using even and odd fields of NTSC as subfields. The aperture ratio may be large or small, but is preferably around 25% because spatial crosstalk between pixels is reduced and display omission between pixels is hardly visually recognized.

In FIG. 1, there is no need to deflect the liquid crystal panel and the optical path for each subfield as in the prior art. Therefore, it is possible to use the same illumination optical system and projection optical system as in the case where the pixel is not multiplied.
In addition, since the MTF of the optical system is not deteriorated, high-resolution display can be performed at low cost. For the high-resolution projection lens 5, it is necessary to secure the same MTF for a spatial frequency twice as high as that of the conventional one, but the design burden of the projection optical system can be greatly reduced. Further, by using the piezoelectric element 7, the displacement amount, that is, the shift amount of the position of the liquid crystal panel 4 can be more accurately controlled as compared with a method using a voice coil, a step motor, or the like. Therefore, since it is not necessary to always feed back the shift amount and perform control, the liquid crystal panel drive unit 11 for displacing (shifting) the liquid crystal panel 4 can be simplified. In addition, since it can be displaced (shifted) to an accurate position, it is possible to perform high-resolution image display at low cost and with little deterioration in image quality due to positional displacement.

The amount of displacement (shift amount) of the piezoelectric element 7 is generally limited by the applied voltage and the number of layers. But,
As shown in FIG. 1, in the image display device for observing a magnified image of 10 to 50 times on the screen 6, the displacement of the original liquid crystal panel 4 is 1
Since it may be as small as / 50 to 1/10, the displacement of the liquid crystal panel 4 can be reduced as an absolute value. Therefore, a displacement within the movable range of the piezoelectric element 7 at a drive voltage of 200 V or less, and in some cases, of 100 V or less is sufficient, and the displacement of the piezoelectric element 7 at a practical drive voltage is hardly restricted. Further, since the conventional illumination optical system and projection optical system can be used as they are, there is no new design burden and a low-cost image display device can be provided. Further, in the case where the liquid crystal panel 4 is not displaced by the piezoelectric element 7, that is, in the display mode in which the pixel is not multiplied, the same optical characteristics as those in the normal mode can be realized. It is easy to do.

As the material of the piezoelectric element 7, a material using a piezo element is preferable. For example, if a piezoelectric element (model number: AE0203D08) manufactured by Tokin Co., Ltd. is used, a displacement of about 6 μm can be obtained at a driving voltage of 100 V. The resonance frequency of the piezoelectric element is 138 kHz, and the resonance frequency is 3 kHz.
A high-speed displacement of about 40 kHz or more can be realized with the one-half frequency as the maximum frequency, and a displacement profile in which the acceleration at the start and end of the displacement is reduced in addition to the rectangular displacement can be realized. .

As a material for the liquid crystal panel 4, a display technology company (US) having pixels of 10 μm pitch is used.
LCOS (Liquid Crystal on S)
Using the i) type spatial modulation element, a reflection type illumination optical system and a projection optical system can be configured to perform four times pixel multiplication. However, as described above, since the requirement for the spatial frequency of the projection lens 5 is doubled due to the high resolution, it is necessary to use a projection lens that supports high resolution. In addition,
In FIG. 1, a real image of the spatial light modulator is formed and enlarged on the screen 6 by the projection lens 5, but the present invention is not limited to this, and an eyepiece is used instead of the projection lens 5. A directly enlarged virtual image may be observed.

FIG. 4 is a timing chart showing an example of the operation of the high resolution image display device of the present invention. As shown in FIG. 4, the x position of the image display element takes two positions x0 and x1, and the y position takes two positions y0 and y1.
According to the combination of the x and y positions, (x, y) is (x1, y1), (x1, y0),
(X0, y1) and (x0, y0) are sequentially displaced,
The respective positions are represented by subfield 1 (SF1), subfield 2 (SF2), subfield 3 (SF3),
Subfield 4 (SF4) is formed, and four subfields are formed.

As for the image display device shown in FIG. 4, the same configuration as the peripheral portion of the liquid crystal panel unit 8 shown in FIG. 1 is used for all the peripheral portions of the liquid crystal panel unit. In the liquid crystal panel 4, although not shown, each pixel has a pixel data storage unit A for inputting pixel data based on a signal from a scanning line. It also has a pixel data storage means B for outputting pixel data different from the means A. Further, a transfer unit that transfers the pixel data of the pixel data storage unit A as the pixel data of the pixel data storage unit B, and a driving unit that can apply a voltage to each pixel based on the pixel data of the pixel data storage unit B Further, the image display device also has transfer timing determining means for transferring the pixel data of the pixel data storage means A substantially simultaneously as the pixel data of the pixel data storage means B by the transfer means for each subfield. ing. Further, in FIG. 4, for simplification of description, one specific data line has four scanning lines. However, the same is true for other data lines. Even in the case where the number of scanning lines is n, the same can be realized by changing the number of writing of the scanning lines from four to n.

Here, in FIG. 4, the image data is
An example is shown in which input is basically performed to the pixel data storage means A in the order of the scanning lines 1, 2, 3, and 4. The image data is converted in advance to image data corresponding to a subfield by an image data processing device (not shown) in order to display one pixel of the image display element by quadrupling the image data. , The image data for four scanning lines is divided into subfields 1,
By being input to the pixel data storage means A in the order of 2, 3, and 4, image data for one image field is input.

If image display is performed as image data corresponding to a scanning line of a specific subfield during a period from the time when certain image data is written to the time when the next image data is written, the difference between the scanning lines Causes a difference in a period in which an image is displayed, and when the image display element is displaced in such a period, spatial crosstalk occurs. Therefore, in the present invention, as shown in FIG. 4, during the time when the image display element is moving (the period of the illumination light OFF shown in FIG. 4), the illumination light irradiation is stopped and the display is not performed. At the same time, the image data of the pixel data storage unit A is transferred to the pixel data storage unit B corresponding to the voltage application drive unit to the pixels at a time during the stop period of the illumination light (according to the transfer command shown in FIG. 4).
It is possible to display a high-resolution and high-contrast image without spatial crosstalk.

More specifically, in FIG. 4, image data is input to the pixel data storage means A in the order of the scanning lines 1, 2, 3, and 4, and the sub data is stored in the pixel data storage means A at a specific timing. Although the state of the field is different for each scanning line, the image data of the pixel data storage unit A is transferred to another pixel data storage unit B for pixel data output at the time when input has been completed for all scanning lines. In the pixel data storage means B, all scanning lines are in the same subfield during the period of the next subfield. Therefore, a voltage is applied to the pixels of the image display element (the liquid crystal panel 4 shown in FIG. 1) by the drive circuit (the liquid crystal panel drive unit 11 shown in FIG. 1) in accordance with the image data contents of the pixel data storage means B, and the pixel switching is performed. By performing the illumination and irradiating the illumination light, the image data input in one subfield period is displayed in one subfield period.

Although FIG. 4 shows an example in which the spatial light modulator is illuminated with illumination light and the light is spatially modulated and controlled, the present invention is not limited to this configuration.
When a light-emitting element such as an L, inorganic EL, or inorganic LED chip array is used, a similar effect can be obtained by directly controlling light emitted from the light-emitting element instead of using illumination light.

Hereinafter, the operation of the high resolution image display device according to the present invention will be described in more detail. FIG. 5 shows a part of a timing chart of the image display device, for explaining the time t _shift required for shifting the image display element and the time t _switch required for switching pixels according to the first and second _aspects . belongs to. In FIG. 5, CLK is an image display clock of the image display device, FP
Is a field pulse for switching fields, and SFP is a subfield pulse for switching subfields. Here, a case where there are four subfields is shown. As described above, the switching of the subfield is performed by driving the piezoelectric element, and a voltage for deforming the piezoelectric element is applied to the piezoelectric element as a drive signal. The deformation of the piezoelectric element based on the drive signal, that is, the switching of the subfield, is performed with the falling of the subfield pulse as a trigger. For driving the piezoelectric element, it is necessary to select the one with the highest responsiveness for high-speed subfield switching,
If the response is too good, attention must be paid to the load due to acceleration applied to the image display element due to the high-speed operation. When the above-described piezoelectric element of 40 kHz is used, the switching of the subfield, that is, the image display element shift is performed in about 2.5 ms as the shortest time. On the other hand, a time t _switch required for pixel switching is a time from a rewriting operation such as application of a voltage to a pixel to completion of rewriting of pixel data.

FIG. 6A shows a timing chart of the image display element shift and the pixel switching described in the first aspect. As described above, in the present image display device, each pixel of the image display element has a pixel data storage unit A for inputting pixel data based on a signal from a scanning line, and the same pixel is stored in the pixel data storage unit A. A pixel data storage means B for outputting pixel data different from the pixel data storage means A, and a transfer means for transferring the pixel data of the pixel data storage means A as the pixel data of the pixel data storage means B. The image display element has driving means capable of applying a voltage to each pixel based on data, and the image display element substantially converts the pixel data of the pixel data storage means A into the pixel data of the pixel data storage means B by the transfer means for each subfield. And an image display device having a transfer timing determining means for simultaneously transferring the image data, whereby the pixel switching is performed for all the pixels. It can be carried out in bulk.

In FIG. 6A, SFP is a subfield pulse signal for subfield switching, and SF
The subfield switches in synchronization with the falling edge of P. The relationship between t _shift and t _switch is t _shift <t _switch
, And the by providing the delay time t _{dela y,} timing allowed to complete the image display device shifts between the start and end of the pixel switching is set by the image display device shifting means. As t _delay , FIG.
As shown in (A), it is desirable to set t _delay = (t _switch −t _shift ) / 2. By making such settings,
For example, when t _shift = 4.2 ms and t _switch = 5.0 ms, t _delay = 0.4 ms is set.

On the other hand, FIG. 6B or FIG.
During the time t _shift of the image display element shift,
FIG. 6A shows a case where a start point of pixel switching is set or a case where an end point of pixel switching is set. In each case, the time until image display is longer than that shown in FIG. Consumes. When the time t _shift required for the image display element shift is set shorter than the pixel switching time t _switch , the pixel shift timing is set so that the image display element shift is completed between the start and the end of the pixel switching. Accordingly, the display time is not substantially delayed due to the time t _shift required for the image display element shift, and the high-speed performance is not impaired. In particular, when a twisted nematic (TN) liquid crystal is used as an image display element material,
This is very useful when a pixel switching time of several ms to several tens ms is required.

On the other hand, FIG. 10A shows a timing chart of the image display element shift and pixel switching described in claim 2. In FIG. 10A, SFP is a subfield pulse signal for subfield switching,
The subfield switches in synchronization with the fall of the FP.
The relationship between t _shift and t _switch is opposite to the case of FIG. _6A , where t _switch <t _shift and from the start to the end of the shift of the image display element by providing the delay time t _delay. The timing for completing the pixel switching is set by the image display element shift means. It is desirable to set t _delay as t _delay = (t _shift −t _switch ) / 2.

In such a relationship, when the image display element is shifted, a force accompanying the acceleration at the time of the shift acts on the image display element. If the force accompanying the acceleration is too large, the structure of the image display element is changed. May change, resulting in breakage.
Therefore, it is desirable to reduce the acceleration at the time of shifting the image display element as much as possible, and in consideration of the load on the image display element material, the pixel switching is not affected by the acceleration or performed when the acceleration is small. Is preferred. Since the acceleration during the shift is generally greatest immediately after the start and immediately before the end of the shift of the image display element, it is preferable to perform the pixel switching operation while avoiding such a period. That is, FIG. 10B or FIG.
Each shows a case where the start point of the image display element shift is set during the pixel switching time t _switch or a case where the end point of the image display element shift is set. Starting point of element shift,
The end point is during the pixel switching period t _switch , which is not preferable.

On the other hand, as shown in FIG.
_By setting _delay = (t _shift −t _switch ) / 2,
It is possible to weaken the acceleration during the shift and reduce the load on the image display element material. By performing such setting, for example, t _shift = 3.20 ms, t _switch = 0.
In the case of 04 ms, t _delay = 1.58 ms is set. Also, the time required for pixel switching t _switch
Is set shorter than the time t _shift required for the image display element shift, the pixel switching timing is set so that the pixel switching is completed between the start and the end of the image display element shift. There is also an advantage that the display time is not substantially delayed due to the required time t _switch and the high speed is not impaired. In particular, ferroelectric liquid crystal (FLC), digital micromirror device (DM)
This is very useful when a material capable of relatively high-speed switching such as D) is used, that is, when the pixel switching time is several μs to several tens μs.

FIGS. 7A and 7B are timing charts of the image display element shift and the pixel switching according to the third aspect. In FIG. 7A, SFP is a subfield pulse signal for subfield switching, and pixel switching is performed in synchronization with the fall of the SFP, and after the pixel switching, the image display element is shifted. Shows the case. On the other hand, FIG. 7B shows a case where an image display element shift is first performed in synchronization with the fall of the SFP, and pixel switching is performed after the image display element shift. In consideration of the load on the image display element material, it is preferable that the pixel switching is performed when the acceleration accompanying the image display element shift is not received. As described above, the acceleration is generally immediately after the start and immediately before the end of the image display element shift. Therefore, it is preferable to perform the image switching operation while avoiding this interval.

FIG. 11 is a block diagram of a graphic controller for controlling the shift of the image display element. The graphic controller may be installed on the input device side such as a personal computer, or may be installed inside the present image display device. Hereinafter, the case where the graphic controller is installed on the personal computer side will be described. FIG. 11 shows a position setting number calculating means 32 for automatically calculating the number of horizontal and vertical position settings of the image display element from the information on the number of pixels in the horizontal direction and the vertical direction in the input image information. A shift control means 33 for setting the order and shift amount of image display element shift based on the number, and an aperture ratio control means 34 for changing a pixel shape or a pixel aperture ratio based on the shift amount are shown.

In FIG. 11, image information stored in the video RAM 36 and the like is input to the control circuit 31 of the graphic controller via the CPU interface, and is roughly divided into a display data signal and a control signal.
When the display data signal is a gray scale display, it is transferred as display data to the image display device via the gray scale control circuit 35. On the other hand, the control signal includes a clock, a frame pulse signal, a sub-frame pulse signal, a latch pulse signal, and the like, and is controlled by the position setting number calculating means 32, the shift control means 33, and the aperture ratio setting means 34, respectively. ,
A control signal is generated and input to the image display device.

The image signal sent from the video RAM 36 or the like has various numbers of display pixels set according to the type of image. For example, if the number of pixels of the image display element of the present image display device is (horizontal) 600 × (vertical) 400 dots, and if the number of pixels of the input image signal is around 600 × 400, the image display element shift and the like are performed. No action is required. However, when the number of pixels of the input image signal is 1200 × 800 dots, it is conceivable that the number of pixels of the input image signal is thinned out to 600 × 400 dots to generate display data of an image. However, the thinning process is not preferable because the resolution of the input image signal is reduced. Therefore, in such a case, high-definition image display according to the input image signal can be performed by setting the image display element to two values per pixel. In the setting processing, the image signals of the video RAM 36 and the like are subjected to number calculation (in this case, two in the vertical direction and two in the horizontal direction) by the position setting number calculating means 32, and the corresponding frame pulse signal, sub-frame pulse signal, latch pulse signal Is obtained, and further passed through the shift control means 33 and the aperture ratio setting means 34 to determine the shift amount aperture ratio. Further, the control signal of the shift control means is transferred to the image display element shift means.

As shown in FIGS. 8A and 8B, there are roughly two types of image display element shift orders when shifting in both the vertical and horizontal directions. FIG. 8A shows the image display element shift only in the vertical direction or the horizontal direction, while FIG. 8B shows the case where the shift also occurs in the oblique direction. In the shift shown in FIG. 8A, the driving of the image display element shift means has an advantage that the period is longer and the load is smaller than that in FIG. 8B. On the other hand, in FIG. 8B, since the vertical and horizontal shifts of the pixels are performed at shorter intervals than in the case of FIG. 8A, there is an advantage that the flicker of the image is reduced. You may comprise so that a user can select which order is used.

FIG. 8C shows that the number of pixels of the input image signal is 18.
This shows a case where the image display element shift is set to three values in the horizontal direction and two values in the vertical direction in the case of 00 × 800 dots. As described above, when the image shift is set to four positions of horizontal binary × vertical binary, setting the aperture ratio to about 25% suppresses the occurrence of crosstalk and reduces the non-image display area. Above was convenient. For the same reason, when setting the image shift to three values in the horizontal direction and two values in the vertical direction, it is convenient to set the aperture ratio to about 17%. Means for automatically performing the setting of the aperture ratio based on the number of position settings, that is,
The pixel aperture ratio setting means will be described with reference to FIG.

In FIG. 9, a pixel aperture ratio setting means 20 is provided on the image display element, that is, on the downstream side of the optical path of the liquid crystal panel 4. The pixel aperture ratio setting means 20 includes a micro lens array 20a in which convex lenses are two-dimensionally arranged corresponding to each pixel of the image display element, and a concave lens corresponding to each pixel of the image display element. It consists of a combination with the microlens array 20b arranged two-dimensionally. The change in the aperture ratio is caused by the micro lens arrays 20a and 20a
It can be operated by controlling the distance to b. Further, by changing the vertical and horizontal positional relationship between the microlens arrays 20a and 20b, the pixel shape can be changed. As for the shift of the image display element, it is preferable that the shift of the image display element, that is, the liquid crystal panel 4 and the deformation setting of the pixel shape by the pixel aperture ratio setting means 20 are simultaneously performed. By changing the pixel shape by the pixel aperture ratio setting means 20 instead of shifting the image display element 4, the same effect as the shift of the image display element can be obtained, but vignetting of display light occurs and efficiency is reduced. Is not preferred. Regarding the pixel aperture ratio setting means 20, in addition to the combination of the convex lens array 20a and the concave lens array 20b shown here, an optical member exhibiting an electro-optical effect (Pockels effect) is provided with a microscopic element corresponding to the number of image display element pixels. By forming cells in an array and controlling the electric field applied to the minute cells, the aperture ratio can be controlled electro-optically. With any of the above means, a high definition image without crosstalk can be obtained by changing the pixel shape using the pixel aperture ratio control means 20.

As shown in FIG. 11, a position set number calculation for automatically calculating the horizontal and vertical position set numbers of the image display elements from the horizontal and vertical pixel number information in the input image information. Means 32, shift control means 33 for setting the order and shift amount of the image display element shift based on the set number of positions, and pixel aperture ratio setting means for changing the pixel shape or pixel aperture ratio based on the shift amount By providing the information 34, it is possible to automatically select a setting for displaying the highest quality image with respect to the pixel number information of the input image.

The shift control means 33 shown in FIG.
Has a function of generating a signal for switching the order of shifting the image display elements every predetermined number of shifts (a predetermined number of times) or every predetermined elapsed time (a predetermined time). The switching signal is transmitted to the shift control unit 3
3 and sent to the image display element shift means. By switching the order of shifting the image display element at a predetermined number of times or at predetermined time intervals, the stress applied to the image display element or the peripheral members of the image display element caused by the image display element shift is averaged, and the durability is improved. be able to. That is, in FIG. 8A, the image display element shift in the clockwise direction is shown, but the switching signal causes the image display element to be rotated counterclockwise every predetermined number of times or every predetermined time, or in FIG. Switching to the image display element shift procedure shown in B) can be performed.

FIG. 12 shows a timing chart of illumination controlled by the illumination light control means and a subfield composed of a plurality of time division frames. FIG.
In each sub-field is configured by a plurality of time-division frames, illumination light wavelength spectrum and illumination light intensity profile are different for each time-division frame, and so as not to be illuminated when switching the sub-field, This shows that the illumination light is controlled by the illumination light control means.

In the present image display device, one image field is constituted by a plurality of subfields. However, when displaying a color image, illumination light having three kinds of light wavelength spectra in each subfield (for example, Light having a center wavelength of 635 nm, 520 nm, or 465 nm) is irradiated. Each wavelength is a wavelength corresponding to red (R), green (G), and blue (B), respectively. By irradiating the illumination light in a time-division manner with high speed switching to the image display element in the order of R → G → B → R... It can be observed as if a color image is displayed.

Further, in the repetition of R → G → B → R..., The light intensity is sequentially changed from the first repetition of the repetition. By turning on the light, gradation display becomes possible. That is, although the time division frame in FIG. 12 shows an example in which the time division frame is divided into five, the illumination light intensity of each time division frame is relatively 1 → 2 as shown in FIG. The image display element is irradiated while changing from → 4 → 8 → 16, and the image display element performs binary spatial light modulation by ON and OFF in each time-division frame. Image display of 32 gradations can be performed in one subfield. Here, for example, when the relationship between the color switching and the light intensity switching shown in FIG. 12 is described as R1 → G1 → B1 → R2 →... → B16, R1 → R2. → G2 ・
・ ・ → G16 → B1 → ・ ・ ・ → B8 → B16
It is possible to change the intensity for each color,
The method of changing the intensity for each color is not preferable because color flicker is easily observed.

FIG. 13 is a timing chart for explaining another illumination method different from the case of FIG. That is, in FIG. 13, a plurality of sub-fields constituting one image field are repeatedly scanned a plurality of times, and illuminations having different illumination light wavelength spectra and illumination light intensity profiles are performed for each scan, and A timing chart is shown in a case where control is performed so that illumination is not performed at the time of subfield switching. Compared to the timing chart in FIG. 12, the switching of the subfields is performed at a higher speed, so that the luminance flicker, the color flicker, and the spatial flicker can be reduced, and an image with less flicker can be obtained.

In an image display device in which a pixel is enlarged and observed, an effective position of the pixel is displaced by changing a positional relationship with an image display element or a lens for enlargement. The position is 1/1 of the original pixel.
It is necessary to precisely control the position of 2 or 1/3 with an accuracy within 1/4 or 1/6 of the original pixel interval.
For example, if the original pixels are at intervals of 10 μm, the accuracy corresponds to within 2.5 μm or within 1.7 μm.
In an image display device in which a liquid crystal panel is formed of a three-panel type of RGB, it is very difficult to realize the accuracy by assembling with mechanical accuracy as compared with a normal resolution, and there is no practical use. The cost is high, and the long-term reliability for transportation, vibration, and the like is low. However, the configuration shown in FIGS. 12 and 13 can be realized using a single-panel type liquid crystal panel.
It is not necessary to adjust the accuracy of the μm class, so that the cost can be reduced and the reliability is greatly improved. Further, since a split optical system for the light source is not required, the size and weight can be reduced.

An image display element material for achieving the time charts shown in FIGS. 12 and 13 will be described below.
First, the speed required for pixel switching when the video rate is 60 Hz will be described. For a video rate of 60 Hz, in FIG. 12, the image field is about 1/60 second (= 16.7 ms). When the image field is divided into four for each subfield, the display time of each subfield is 16.7 / 4 = 4.2 ms, and each subfield is divided into five time division frames.
Further, since each time-division frame displays an image corresponding to light of three wavelengths, the illumination time of light of each wavelength is 4.2 / (5 × 3) = 0.28 ms. Actually, the time required for the shift of the image display element is also required, so that the illumination time is further shortened. In order to display images favorably within such an illumination time, it is desirable that the response speed of the pixel switching be 0.07 ms, which is about 1/4 of the illumination time, that is, 70 μs or less. Increasing the number of subfields and the number of time-division frames further increases the required speed of the pixel switching.

In a conventional image display device based on a TN liquid crystal having a slow response speed, the pixel switching time requires several milliseconds (ms) or more, and therefore cannot be used in the above-described image display device of the present invention. On the other hand, ferroelectric liquid crystal (FL)
The pixel switching time of C) depends on conditions such as operating temperature and the like, but is generally about several tens μs, which is suitable for the image display device of the present invention. Also, in a high-speed image display element in which a micromirror is formed on silicon, that is, a digital micromirror device DMD (Texas Instruments, USA), the pixel switching time is several tens μs, and there is no problem in terms of response speed. However, since it is a configuration in which the micromirror is finely moved with the hinge as a support for switching, when the image display element shift of the present image display device is applied,
Damage is likely to occur depending on the shift direction of the image display element, and care must be taken.

Next, the ferroelectric liquid crystal material used in the present image display device will be further described. As a ferroelectric liquid crystal material for an image display device, a side chain type is generally used among liquid crystal polymers, and a methylene chain having a flexible main chain such as polyacrylate, polymethacrylate, polysiloxane, or polyoxyethylene. A mesogen hangs as a side chain via a spacer composed of the same. further,
At the molecular terminal of the side chain, there is an asymmetric carbon, and the rotation of the permanent dipole in the molecule carrying the -COO- group near the asymmetric carbon around the major axis of the molecule is biased, resulting in ferroelectricity. The spontaneous polarization which is the reason occurs (references; for example, “The Latest in Liquid Crystal Displays” edited by Young Researchers Group for Liquid Crystals). When configured as an image display element, such spontaneous polarization splits into two states, up or down, with respect to the substrate interface, and is made bistable, so that the polarization state is maintained even when an external electric field is removed, indicating memory properties. .
The ferroelectric liquid crystal material has high viscoelasticity due to a polymer, and once the molecular orientation is broken by an impact, unlike a TN liquid crystal, self-alignment cannot be achieved. That is, the disorder of the molecular orientation due to the impact becomes a fatal defect,
Special considerations are preferred. Such a disorder of the molecular orientation is expected to increase the probability of occurrence when the image display element shift and the image switching are performed at the same time. Therefore, in the present image display device, the pixels in which the display state needs to be changed need to be changed. Only the pixel switching operation is performed, and the other pixels are provided with pixel state control means for maintaining the current state.

As described above, since the ferroelectric liquid crystal material has a memory property, once a pixel signal is written, it has a property of maintaining the written state even when the external electric field is stopped.
At the time of image display, the current off / off state of a certain pixel and the off / off state of an image signal to be displayed subsequently are compared in advance, and if there is no change before and after, no external electric field is applied and the pixel is turned off. Is maintained. Even if no external electric field is applied, no problem occurs in the display state of the pixel. Therefore, as described above, it is possible to obtain an advantage that the occurrence of disorder in molecular orientation can be reduced, which contributes to improvement in durability of the image display element. That is, when changing a display image corresponding to a temporally continuous subfield or a continuous time-division frame, a pixel switching operation is performed only on a pixel whose display state needs to be changed, and no change is required. By providing the pixel state control means for maintaining the current state of the pixel, ion destruction of the ferroelectric liquid crystal can be prevented, and reliability can be improved.

In the ferroelectric liquid crystal, a process for neutralizing the residual charge due to polarization is required, and in the present image display device, consideration must be given to the timing of shifting the image display element. That is, when the residual charge is left unattended, or when an electric field is further applied in the same direction as the residual charge, the possibility of ionic breakdown of the ferroelectric liquid crystal increases. Therefore, in the present image display device, when changing a display image corresponding to a temporally continuous subfield or a continuous time-division frame, a pixel switching operation is performed on a pixel whose display state needs to be changed. If so, a process for relaxing the polarization of the pixel is performed immediately before the pixel switching operation. In addition, since the external electric field application and the image display element shift for neutralizing the residual charge as the relaxation treatment are not performed at the same time, the occurrence of disorder in the molecular orientation can be reduced, and the durability of the image display element is improved. Can be done. That is, when a display image is changed corresponding to a temporally continuous subfield or a continuous time-division frame, a pixel switching operation is performed on a pixel whose display state needs to be changed. Immediately before the process of relaxing the polarization of the pixel, the ion destruction of the ferroelectric liquid crystal can be prevented, and the reliability can be improved.

[0074]

According to the present invention, the time required for the image display element shift is set shorter than the pixel switching time, and the image display element shift timing is set between the start and the end of the pixel switching. By setting the shift to be completed, the display time is not substantially delayed due to the time required for shifting the image display element, and the high-speed operation is not impaired. In particular, twisted nematic type (T
N) It is very useful when a pixel switching time of several ms to several tens ms is required as in the case of using liquid crystal.

(Claim 2) Damage to the image display element due to acceleration acting when shifting the image display element can be avoided or greatly reduced. In addition, by setting the pixel switching to be completed between the start and the end of the image display element shift, a delay in the display time due to the time required for the pixel switching can be substantially prevented, and the high-speed operation can be achieved. It is not spoiled. In particular, when a material capable of relatively high-speed switching such as ferroelectric liquid crystal (FLC) is used as an image display element material, that is, when a pixel switching time is several μs to several tens μs, it is very useful. In addition, a defect caused by constantly shifting the image display element during the operation of the apparatus, that is, the acceleration applied to the image display element at the time of shifting the image display element makes it easy for the composition of the image display element material to change, thereby reducing durability. Factors such as deterioration can be improved.

(Claim 3) Damage to the image display element due to acceleration acting when shifting the image display element can be further avoided or greatly reduced. That is, it can be further reduced than the case described in claim 2.

(Claim 4) Position setting number calculating means for automatically calculating the horizontal and vertical position setting numbers of the image display elements from the horizontal and vertical pixel number information in the input image information. By providing a shift control means for setting the order of image display element shift and the shift amount based on the set number of positions, a setting for displaying an appropriate highest quality image corresponding to an input image signal is automatically selected. It is possible to do.

(5) The shift control means switches the order of the shifts at a predetermined number of shifts or at a predetermined elapsed time, so that the image display element or the image display element of the image display element is associated with the shift. The stress applied to the peripheral members is averaged, and the durability is improved.

(Claim 6) By having the pixel aperture ratio setting means capable of automatically or manually changing the pixel aperture ratio, crosstalk between pixels which may occur due to the shift of the image display element is reduced. It is possible to suppress the display omission between the pixels and make the display less visible.

(Claim 7) A color display method suitable for an image display device in which one image field is constituted by a plurality of subfields can be provided. Each sub-field is composed of a plurality of time-division frames, and the illumination light control means illuminates with different illumination light wavelength spectrum and illumination light intensity profile for each time-division frame, and
By controlling so that illumination is not performed at the time of subfield switching, a high-quality color image can be obtained with one image display element, and the number of components of the optical system can be further reduced, so that cost is reduced and weight is further reduced. Size and size can be reduced. Compared with the method described in claim 8, the frequency of subfield switching is low, which is advantageous in terms of durability. Since illumination is not performed at the time of switching the subfields, disturbance of the image at the time of switching the subfields is not recognized by the observer, so that image degradation can be prevented.

(Claim 8) Compared to claim 7, since the switching of the subfield is faster, the luminance flicker, the color flicker, and the spatial flicker are reduced, and an image without flicker is obtained. Further, as in the case of the seventh aspect, a high-quality color image can be obtained with one image display element, and the number of components of the optical system can be further reduced, so that the cost can be reduced, and further, the weight and size can be reduced. .

(Claim 9) An image display element material suitable for the present image display device can be provided.

(Claim 10) When a display image is changed corresponding to a temporally continuous subfield or a continuous time-division frame, a pixel switching operation is performed only on a pixel whose display state needs to be changed, By providing pixel state control means for maintaining the current state of the other pixels, ion destruction of the ferroelectric liquid crystal can be prevented, and reliability can be improved.

(Claim 11) When a display image is changed corresponding to a temporally continuous subfield or a continuous time-division frame, a pixel switching operation is performed on a pixel whose display state needs to be changed. By performing a process for relaxing the polarization of the pixel immediately before the pixel switching operation, the ion destruction of the ferroelectric liquid crystal can be prevented, and the reliability can be improved.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing one embodiment of a liquid crystal panel unit of the high resolution image display device according to the present invention.

FIG. 3 is an enlarged view of a pixel portion of a liquid crystal panel in a liquid crystal panel unit according to the present invention.

FIG. 4 is a timing chart showing an example of the operation of the high-resolution image display device according to the present invention.

FIG. 5 is a diagram showing a part of a timing chart for explaining the operation of the high-resolution image display device according to the present invention.

FIG. 6 is a timing chart showing an embodiment of image display element shift and pixel switching according to the present invention.

FIG. 7 is a timing chart showing another embodiment of the image display element shift and the pixel switching in the present invention.

FIG. 8 is a configuration diagram showing an example of an image display element shift order in the present invention.

FIG. 9 is an optical path diagram illustrating an example of a pixel aperture ratio setting unit according to the present invention.

FIG. 10 is a timing chart showing still another embodiment of the image display element shift and the pixel switching in the present invention.

FIG. 11 is a block diagram of a graphic controller that controls image display element shift according to the present invention.

FIG. 12 is a timing chart showing one embodiment of a subfield configuration and an illumination method controlled by illumination light control means in the present invention.

FIG. 13 is a timing chart showing another embodiment of the illumination method controlled by the illumination light control means and the configuration of the subfield in the present invention.

FIG. 14 is a configuration diagram showing an embodiment of a conventional high-resolution image display device.

FIG. 15 is a configuration diagram showing another example of a conventional high-resolution image display device.

FIG. 16 is a configuration diagram showing still another embodiment of the conventional high-resolution image display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Illumination light source, 2 ... Diffusion plate, 3 ... Condenser lens, 4
... liquid crystal panel, 5 ... radiation lens, 6 ... screen, 7,
7 ': piezoelectric element, 8: liquid crystal panel unit, 9, 9' ...
Liquid crystal panel support, 10: light source drive unit, 11: liquid crystal panel drive unit, 12: piezoelectric element drive unit, 13 ...
x-axis direction displacement, 14 ... y-axis direction displacement, 15a, 15
b, 15c, 15d: subfield, 20: pixel aperture ratio setting means, 20a, 20b: microlens array,
Reference numeral 31: graphic controller control circuit, 32: position setting number calculation means, 33: shift control means, 34: aperture ratio control means, 35: gradation control circuit, 36: video RA
M, 51: image display LCD panel, 52: LCD drive circuit, 53: optical path changing means, 53a: eyepiece, 5
3b: lens mount, 53c: voice coil, 54: voice coil drive circuit, 61: polarization plane rotating member, 62
... birefringent plate, 63 ... liquid crystal plate, 64, 65 ... transparent electrode, 6
6. Liquid crystal drive circuit.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G09G 3/20 680 G09G 3/20 680F 3/36 3/36 H04N 5/74 B H04N 5/74 G02F 1 / 137 510 (72) Inventor Hiroyuki Sugimoto 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Yasuyuki Takiguchi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company F Terms (reference) 2H088 EA10 EA12 EA19 HA06 JA17 MA02 MA05 2H093 NC43 NC44 ND43 5C006 AF44 BA12 BB28 EA01 EA03 EC11 FA11 FA23 5C058 AA06 BA23 BA35 EA02 EA26 EA42 EA51 5C080 AA10 BB05 DD29 EJ05

Claims (11)

[Claims] An image display device for observing a small image display element having a plurality of pixels capable of controlling irradiation light in accordance with image information as an enlarged image enlarged by an optical element, and comprising a plurality of image fields An image display device having an image display element shift means comprising a piezoelectric element, wherein the image display element shift means shifts the image display element substantially in the direction of the arrangement plane of the pixels in accordance with the subfields. The time required for the shift of the pixel is set shorter than the time required for the switching of the pixel, and the timing for completing the shift of the image display element is set between the start and the end of the switching of the pixel. Image display device. 2. An image display device for observing a small image display element having a plurality of pixels capable of controlling irradiation light in accordance with image information as an enlarged image obtained by enlarging with an optical element, and comprising a plurality of image fields. An image display device having an image display element shift means comprising a piezoelectric element, wherein the image display element shift means shifts the image display element substantially in the direction of the arrangement plane of the pixels in accordance with the subfields. The time required for the shift of the pixel is set longer than the time required for the switching of the pixel, and the timing for completing the switching of the pixel is set from the start to the end of the shift of the image display element. Image display device. 3. An image display device for observing a small image display element having a plurality of pixels capable of controlling irradiation light in accordance with image information as an enlarged image obtained by enlarging with an optical element, and comprising a plurality of image fields. An image display device having an image display element shift means composed of a piezoelectric element, which shifts the image display element in the direction of the substantially array surface of the pixels in accordance with the subfields. An image display device characterized in that the switching operation of the pixels for displaying the image is terminated before the shift of the image display element is started or is set to be started after the shift is completed. 4. A number-of-positions calculating means for automatically calculating the number of horizontal and vertical positions of an image display element from information on the number of horizontal and vertical pixels in input image information; 4. The graphic controller used in the image display device according to claim 1, further comprising: a shift control unit configured to set a shift order and a shift amount of the image display elements based on the number. 5. The method according to claim 1, wherein the presence / absence of the shift operation, the shift order at the time of the shift operation, and the setting of the shift amount are automatically switched every predetermined number of times of the shift or every predetermined elapsed time. A graphic controller used in the image display device according to claim 4. 6. An image display device for observing a small image display element having a plurality of pixels whose illumination light can be controlled in accordance with image information as an enlarged image enlarged by an optical element, and comprising a plurality of image fields. A pixel aperture ratio setting means for automatically or manually changing a pixel aperture ratio or a pixel aperture shape in an image display device capable of shifting the image display element in the direction of a substantially array surface of pixels in accordance with the subfields An image display device comprising: 7. An image display device for observing a small image display element having a plurality of pixels capable of controlling illumination light in accordance with image information as an enlarged image enlarged by an optical element, and comprising a plurality of image fields. In the image display device having an image display element shift means composed of a piezoelectric element for displacing the image display element in a direction substantially corresponding to the arrangement plane of the pixels corresponding to the subfields, each of the subfields is constituted by a plurality of time division frames The illumination light wavelength spectrum and the illumination light intensity profile are different for each time-division frame, and illumination light control means is provided to control the illumination so as not to be performed when the subfield is switched. The image display device according to claim 1, 2, 3, or 6. 8. An image display device for observing a small image display element having a plurality of pixels capable of controlling illumination light in accordance with image information as an enlarged image enlarged by an optical element, and comprising a plurality of image fields. In the image display device having an image display element shift means composed of a piezoelectric element, which displaces the image display element in the direction of the substantially array plane of the pixels in accordance with the subfields, a plurality of subfields forming one image field are Illumination light control means for performing scanning repeatedly several times, performing illumination with a different illumination light wavelength spectrum and illumination light intensity profile for each scan, and performing control so that no illumination is performed when the subfield is switched. The image display device according to claim 1, wherein the image display device has: 9. A reflection type structure in which a plurality of pixels for controlling illumination light of an image display element are made of a ferroelectric liquid crystal material, and illumination light enters and exits the image display element through the same surface. 4. The method according to claim 1, wherein
Or the image display device according to 6 or 7 or 8. 10. When a display image is changed corresponding to a temporally continuous subfield or a continuous time-division frame, a pixel switching operation is performed only on a pixel whose display state needs to be changed, and the display state is changed. 10. The image display device according to claim 9, wherein a pixel that does not need to be changed has a pixel state control unit that holds a current state. 11. When changing a display image corresponding to a temporally continuous subfield or a continuous time-division frame, performing a pixel switching operation on a pixel whose display state needs to be changed. The image display device according to claim 9, wherein an operation of relaxing polarization of the pixel is performed immediately before the switching operation.