JPH0618838A - Liquid crystal projection type display - Google Patents

Abstract

PURPOSE:To provide the projection type liquid crystal display of high definition and high luminance by constituting the display so that it is compatible to display an image of full resolution and to secure brightness of a screen, which become a problem in a work station, an HDTV, etc. CONSTITUTION:This display is constituted by providing reflection type projection optical system constituted by providing light sources 6, 13, reflecting mirrors 7, 14, a condenser lens 8, projection lens systems 9, 16, internal reflecting mirrors 10, 17, liquid crystal cells 4a-4c, 11a-11c and dichroic prisms 5, 12, and a screen control circuit system 3. Accordingly, the liquid crystal projection type display of high definition and high luminance can be realized, and a large screen display whose quality does not deteriorate even in a bright room can be realized.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to improving the quality of a liquid crystal projection display. In particular, the present invention relates to a technique for increasing the resolution, brightness, and screen of a liquid crystal projection display.

[0002]

2. Description of the Related Art Regarding conventional liquid crystal projection type displays, for example, International Symposium Digest of S. ID (1986), pages 375 to 378 (International Symposium
Digest of SID pp375-378 (1986)), a TFT (Thin Film Transisto) using a polycrystalline silicon thin film is described.
3) combining r) technology and TN type liquid crystal (Twisted Nematic)
A liquid crystal projection display using a transmissive TFT / TN type liquid crystal panel is described.

In addition, instead of the TN type liquid crystal, a liquid crystal projection type display using a polymer dispersion type liquid crystal in which a liquid crystal is dispersed in a transparent resin and a TFT is international.
Symposium Digest of S. ID (1990), pages 227-230 (Intern
ational Symposium Digest of SID pp227-230 (1990))
It is described in.

In these liquid crystal projection type displays, light emitted from a light source is input to a liquid crystal element, and light output from the liquid crystal element is projected on a screen through a projection lens system to display an image. It was.

[0005]

Among the above-mentioned prior arts, for example, in a liquid crystal projection display using a transmissive TFT / TN liquid crystal panel, the polarization effect is used for display. That is, the light from the light source is unpolarized, but becomes linearly polarized by passing through the polarizing plate. The transmittance of the normally used polarizing plate is about 40%, and 60% or more of the light incident on the liquid crystal panel is blocked by the polarizing plate and is ineffective.

Further, a TFT element is formed of opaque polycrystalline silicon on a transparent glass substrate, and a metal thin film of aluminum, chromium or the like is used for wiring. Therefore, the TFT substrate has a portion that cannot transmit light and cannot be used as a pixel. The area of the pixel area where light can be effectively controlled is defined as "effective pixel area", and the aperture ratio is determined by the relationship with the "pixel pitch", which is the distance between pixels (defined as "effective pixel area / pixel pitch ² "). Will affect the efficiency of light utilization. The size of the liquid crystal panel used for the projection type display is much smaller than that of the liquid crystal panel (usually about 10 inches diagonally) used in personal computers and the like, and the size of the projection lens and other optical systems is large. In consideration of this, it is about 2 to 3 inches diagonally. For this reason, the above-mentioned aperture ratio is inevitably small, and is about 40% in a liquid crystal panel used for a normal television. Considering the light loss due to the above-mentioned polarizing plate, the transmittance of the liquid crystal panel drops to a value of about 16% at most. This transmissivity inevitably decreases as the screen resolution increases, and for example, in HDTV (High Definition Television) that features high-definition images, the transmissivity decreases to several percent. Further, since the polymer dispersion type liquid crystal panel outputs an image by using the difference between the scattering state and the transparent state of light, the liquid crystal projection type display using the polymer dispersion type liquid crystal panel does not utilize the polarization effect, so that the polarizing plate is used. The light loss goes away. However, since a transmissive liquid crystal panel is used, light loss occurs according to the aperture ratio, and HDTV is
Although the transmittance is higher than that of the transmissive TFT / TN liquid crystal panel, it is still around 10%. As described above, in the liquid crystal projection display using the transmissive liquid crystal panel, the light utilization efficiency is low, and it is very difficult to create a bright screen. Needless to say, improvement in image quality such as higher resolution and higher brightness is one of the greatest needs. Furthermore, HDTV with higher resolution than ordinary TV
The spread of (High Definition Television) and the like is imminent, and it is necessary to realize higher resolution projection type displays in the future. In this case, the aperture ratio is further reduced and the brightness of the screen is reduced, and the problem is to significantly improve the light utilization efficiency.

Further, as described above, a portion where no light is present exists between each pixel in a black frame shape. Therefore, there is a problem in that the image is not smooth when displaying an image without discontinuity such as a natural image in which the pixels are not connected to each other. Therefore, in order to improve the image quality, it is necessary to erase this black frame portion. An object of the present invention is to provide a liquid crystal projection display capable of displaying a high-resolution screen, a small-sized, light-weight and high-luminance projection display capable of significantly improving light utilization efficiency and obtaining a bright screen. Another object of the present invention is to provide a liquid crystal projection type display that further eliminates breaks between pixels and creates an image that gives a smooth texture.

[0008]

[Means for Solving the Problems] In order to solve the above problems, the following means can be considered. First, a reflection type optical system including a light source, a condenser lens, a projection lens, and means for demultiplexing and combining light of the light source for each wavelength band, and a reflection type liquid crystal cell including a scattering type liquid crystal layer, In a liquid crystal projection type display having a screen control circuit for controlling a screen, the reflection type liquid crystal cells forming one screen are divided into a plurality of liquid crystal cell groups, and the liquid crystal cell groups are divided into respective liquid crystal cell groups. A liquid crystal projection type display provided with the reflection type optical system is conceivable.

Further, a reflection type optical system having a light source, a condenser lens, a projection lens, and means for demultiplexing and combining the light of the light source for each wavelength band, and a reflection type liquid crystal having a scattering type liquid crystal layer. In a liquid crystal projection display including a cell and a screen control circuit for controlling the screen, the reflective liquid crystal cells forming one screen are arranged in a liquid crystal cell array corresponding to a scanning line of the liquid crystal projection display. A liquid crystal cell row is divided into a first liquid crystal cell group consisting of liquid crystal cell rows corresponding to even-numbered scanning lines and a second liquid crystal cell group consisting of liquid crystal cell rows corresponding to odd-numbered scanning lines, and The first liquid crystal cell group is provided with liquid crystal driving elements at positions corresponding to odd-numbered scanning lines, and the second liquid crystal cell group is provided with liquid crystal driving elements at positions corresponding to even-numbered scanning lines. each A liquid crystal projection display in which one image is created by synthesizing images projected by the first liquid crystal cell group and the second liquid crystal cell group by the reflection type optical system provided in the liquid crystal cell group To be

Further, a liquid crystal projection display in which the first liquid crystal cell group and the second liquid crystal cell group respectively include a red display liquid crystal cell, a green display liquid crystal cell and a blue display liquid crystal cell is also conceivable.

Further, the reflection type liquid crystal cell may be a liquid crystal projection type display in which a single crystal silicon plate is used as a substrate and an active element is provided on the substrate.

Further, a configuration using a polymer dispersion type liquid crystal as the reflection type liquid crystal cell is also conceivable.

[0013]

In order to improve the light utilization efficiency, a reflective liquid crystal panel is used instead of the conventional transmissive liquid crystal panel. In the TFT substrate used for the transmissive liquid crystal panel, it is necessary to secure a sufficient space between the pixel electrode and the circuit portion such as the transistor and each wiring portion in order to avoid a defect due to a short circuit of the circuit. By using the liquid crystal panel, it is possible to completely separate the circuit portion, the wiring portion, and the pixel electrode by providing them in different layers. This eliminates the need for a space between the pixel electrode and the circuit section or wiring section, thus making it possible to increase the effective pixel area. Furthermore, by providing a thin film of aluminum or the like that is a reflective film so as to cover the pixel transistor and the wiring portion, it is possible to use the above-mentioned transistor and wiring portion that cannot be used conventionally as an effective pixel. Become. Further, by configuring one screen with a plurality of liquid crystal panels, the effective pixel area can be further expanded. That is, the pixel rows that make up one liquid crystal panel are
For example, it is divided into a first liquid crystal panel composed of odd-numbered pixel columns and a second liquid crystal panel composed of a plurality of pixel columns. In the first liquid crystal panel, necessary circuits and the like are arranged in portions corresponding to a plurality of pixel columns.
The necessary circuits and the like are arranged in such a portion because this portion does not affect the display screen. Similarly, in the second liquid crystal panel, necessary circuits and the like are arranged in portions corresponding to odd-numbered pixel columns. Finally, by combining the images projected by the first liquid crystal panel and the second liquid crystal panel with, for example, an optical system, it is possible to provide a liquid crystal display that can achieve high brightness while ensuring high resolution. become. Furthermore, by providing the first liquid crystal panel and the second liquid crystal panel with a red display liquid crystal cell, a green display liquid crystal cell, and a yellow display liquid crystal cell, respectively, a display capable of color display can be configured.

By using a polymer dispersion type liquid crystal as the liquid crystal device, it is possible to further increase the brightness of the display screen.

[0015]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the configuration of a liquid crystal projection display according to the present invention.

In this embodiment, the light sources 6 and 13 and the reflecting mirrors 7 and 1 are used.
4, condenser lens 8, projection lens systems 9 and 16, internal reflecting mirrors 10 and 17, and liquid crystal cells 4a, 4b, 4c and 11
a, 11b, 11c and dichroic prisms 5, 12
It is configured to have the reflection type projection optical systems 1 and 2 and the screen control circuit system 3 that are provided.

The liquid crystal projection type display has two sets of reflection type projection optical systems 1 and 2.
The function of the reflective projection optical system will be described by taking the reflective projection optical system 1 as an example. The white projection light 18 generated by the light source 6 is reflected by the reflecting mirror 7 and enters the condenser lens 8. White projected light 18 condensed by the condenser lens 8
Is a small reflecting mirror 1 provided inside the projection lens system 9.
It is reflected by 0 and enters the dichroic prism 5. The dichroic prism 5 is an optical device that decomposes incident white light into light of three colors of red, blue, and green corresponding to the three primary colors of light. Of the white projection light 18 incident on the dichroic prism 5, the red light 18 on the long wavelength side is generated by the surface 5a existing in the dichroic prism 5.
a is reflected.

Similarly, the blue light 1 on the short wavelength side is reflected by the surface 5b.
8c is reflected, and only the remaining green color 18b passes through the dichroic prism 5.

The projected lights 18a, 18b, 18c demultiplexed by the dichroic prism 5 respectively enter the reflection type liquid crystal cells 4a, 4b, 4c and are reflected by the cells. At this time, the projection light incident on each reflective liquid crystal cell is
The incident angle is about 1 to 5 degrees with respect to the vertical direction of the incident surface. The reflected projection lights 18a, 18b, 18c are combined by the dichroic prism 5 this time, returned to the white projection light 18, and are incident on the projection lens system 9.

As described above, since the projection light incident on each reflection type liquid crystal cell has an incident angle of about 1 to 5 degrees with respect to the direction perpendicular to the incident surface, the combined projection light is obtained. 18
Is not blocked by the reflecting mirror 10 in the projection lens system, passes through the projection lens system 9, and is projected on the external screen 19. For example, a red image signal is applied to the reflective liquid crystal cell 4a from the screen control circuit system 3 to modulate red projection light. Similarly, a green image signal is applied to the reflective liquid crystal cell 4b from the screen control circuit system 3 to modulate the green projection light, and the reflective liquid crystal cell 4c receives a blue image from the screen control circuit system 3. A signal shall be given to modulate the blue projected light. With the above configuration, a color image is reproduced. The reflective projection optical system 2 also projects the projection light on the screen 19 by the same operation. The optical system of the reflective projection optical system 2 is arranged in line symmetry with the optical system of the reflective projection optical system 1. In other words, this is because the reflective projection optical system 1 reproduces half the image of one screen, and the reflective projection optical system 2 reproduces the other half image.
Next, a method of dividing a screen will be described with reference to FIG. The screen 20 is configured by arranging pixels 21 two-dimensionally. 2, the line numbers on the scanning line side are set to 1, 2, ..., N (where N is an integer) in order from the top for the sake of explanation. For example, the integer N is 480 in the NTSC signal system and is an even number. The screen division is performed by paying attention to the scan line number and whether the number is an even number or an odd number. That is, paying attention to the arrangement of the pixels forming the screen on the scanning line side, every other column is extracted.

As a result of the above operation, the divided screen has a screen 22 in which the pixels of only the lines having an odd scanning line number in the original screen are collected, and a pixel in the lines of only the lines having an even scanning line number in the original screen. The screen 23 is divided into

When the pixel pitch (interval between pixels) in the original screen 20 is P, the pixel pitch in the scanning line direction of the divided screens 22 and 23 is 2P, which is double, but the size of the pixel is It is the same as the original screen. The two screens 22 and 23 are combined on the screen by the optical system shown in FIG. 1 to reproduce the original screen having the pixel pitch P. In the case of a display using the NTSC signal system, it is normally 640 in the horizontal direction (signal line side) and 4 in the vertical direction (scan line side).
Eighty pixels are arranged. When the diagonal screen size of the liquid crystal panel is 50.8 (mm) (2 inches), the pixel pitch of the original screen is about 64 × 64 μm. Further, in the case of a high-definition screen (1280 × 1024 pixels), when the diagonal screen size is 50.8 (mm) (2 inches), it is about 32.
X30 μm, which is even smaller.

Next, the structure of the pixels forming the divided screen will be described.

FIG. 3 shows the screen 22 shown in FIG.
FIG. 4 is a plan configuration diagram of pixels in odd lines, and FIG. 4 is a plan configuration diagram of pixels in even lines in the screen 23 shown in FIG. 2.

In FIG. 3, for the sake of explanation, the odd line 3 ×
The matrix of two pixels is extracted from the liquid crystal panel and shown. Of the six pixels shown, the pixel Aa shows the state of the pixel electrode, the pixel Ca sees through the pixel electrode, shows the state below the electrode, and the remaining four pixels Ab to Cc are
The state when actually projecting on the screen is shown.

There are a plurality of pitches 2P arranged in parallel.
The scanning electrode wirings 24 are arranged laterally with respect to the screen. The gate electrode 24a of the transistor is formed in a state of protruding from a part of the scan electrode wiring 24. A plurality of parallel signal electrode wirings 25 orthogonal to the scanning electrode wirings 24
Are arranged in the vertical direction of the screen.

A transistor 26 is arranged so as to cover a part of the signal electrode wiring 25 and the gate electrode 24a.

The transistor 26 is formed in a portion corresponding to the pixels on the even lines of the original screen shown in FIG.

The pixel electrode 27 bisects the pixel of the odd line and the pixel of the next even line of the original screen, and completely covers the circuit portion composed of the above transistor as shown by the pixel Aa. The circuit portion below the pixel electrode is invisible from the outside. The pixel electrode is formed of, for example, a metal thin film having a high reflectance characteristic of aluminum, chromium, or the like, a dielectric multilayer film in consideration of the wavelength characteristic of reflected light, or the like. When wirings, transistors, etc. are formed on a single crystal silicon substrate, the surface shape becomes complicated and large unevenness occurs. For this reason, the thin film used as the pixel electrode formed on the upper part also has unevenness depending on the shape of the base.

The uneven pixel electrode portion scatters and reflects incident light. Transistors, wiring, etc. at the bottom
The part of the pixel electrode that does not exist becomes flat. When such a pixel is projected on the screen by the optical system shown in FIG. 1, a portion where the pixel electrode is uneven as shown by pixels Ab to Cc becomes a dark portion 28a and is flat on the screen. The pixel electrode portion becomes a bright portion 28b on the screen. The pixel electrode that covers the top of the transistor is
There is a light-shielding effect on the projected light with high light intensity.

In FIG. 4, for the sake of explanation, 3 × 2 even lines are used.
The pixel matrix is extracted from the liquid crystal panel for illustration. Of the six pixels shown, the pixel Ba shows the state of the pixel electrode, the pixel Da shows the state below the electrode through the pixel electrode, and the remaining four pixels Bb to Dc are actually on the screen. Shows the state when projected on. Scan electrode wiring 29, gate electrode 29a,
The signal electrode wiring 30 and the transistor 31 are arranged. The transistor 31 is arranged in a portion corresponding to the pixel of the odd line of the original screen shown in FIG. The pixel electrode 32 is
The pixel of the even line of the original screen and the pixel of the next odd line are cleaved to completely cover the above circuit portion as indicated by pixel Ba.

The pixel electrode portion, which has unevenness depending on the shape of the base, scatters and reflects the incident light, but when projected onto the screen by the optical system, the pixel electrode has unevenness as shown by pixels Bb to Dc. The portion where the line is generated becomes the dark portion 33a on the screen, and the portion of the flat pixel electrode becomes the bright portion 33b on the screen. By optically combining the images of the two liquid crystal panels having the pixels arranged as shown in FIGS. 3 and 4, it is possible to reproduce the screen of the original definition.

As described above, the transistors of the odd line and the even line are independently formed on different liquid crystal panels, so that the transistor can be arranged below the pixel electrode portion which is not displayed. Therefore, it is possible to prevent the influence of the enlargement of the size of the transistor with respect to the reduction of the size of the pixel, and it is possible to realize the high definition of the image quality without lowering the aperture ratio. The operation principle of the polymer dispersed liquid crystal will be described with reference to FIGS.

Generally, a polymer-dispersed liquid crystal is structurally
There are two types. In the polymer-dispersed liquid crystal having the structure shown in FIG. 5, a nematic liquid crystal 82 is dispersed in a water-soluble polymer 81 such as polyvinyl alcohol (PVA) in a spherical shape or a shape close to an elliptic shape. The polymer-dispersed liquid crystal having the structure shown in FIG. 6 has a nematic liquid crystal 92 in a porous polymer layer 91 such as an ultraviolet curable resin.
Is impregnated with. The polymer-dispersed liquid crystal having any structure optically exhibits a scattering state in a normal state. When the external electric field 83 is applied to the polymer containing nematic liquid crystal, the nematic liquid crystal molecules are aligned in the electric field direction and become in a transparent state. The polymer-dispersed liquid crystal controls the incident light in the two states of the transparent state and the scattering state. Since no polarizing plate is used, the transmittance of the polymer-dispersed liquid crystal panel in the transparent state reaches 80 to 90%,
It has a transmittance that is more than twice that of a conventional TN liquid crystal panel.
As described above, in the case of the polymer dispersion type liquid crystal panel, the optical scattering state and the transparent state are used. Therefore, in the liquid crystal projection display using the polymer dispersion type liquid crystal panel, the difference between the scattered state and the transparent state of the light reflected by the liquid crystal panel is received by the projection lens and projected on the screen to obtain the image contrast. Therefore, in order to obtain high contrast, it is necessary to prevent light scattering in the transparent state. However, if unevenness is present in the reflective film, light is scattered according to the unevenness, so that the polymer-dispersed liquid crystal does not become transparent even when a voltage is applied.

For this reason, the brightness of the screen is lowered when a voltage is applied, and the contrast is eventually lowered. Therefore, in order to realize high contrast, it is important to secure the flatness of the reflective film. In this embodiment, the flatness of the single crystal silicon substrate can be used as it is.

The signal source of the liquid crystal projection display is, for example, an NTSC television signal or HDT.
Analog such as V (High Definition Television) signal,
There are interlace signal systems and digital and non-interlace signal systems such as personal computers. The screen control circuit system in the case of using the image source of the analog and interlace signal system will be described with reference to FIG. Image signal source 34
Is composed of a tuner, a video recorder, and the like. The image signal 41 output from the image signal source 34 is an analog interlace signal, and generally forms one frame (one screen) image in two fields.

The image signal 41 is separated by the sync separation circuit 35 into a horizontal sync signal and a vertical sync signal. Next, the timing control circuit 36 generates a clock signal and separates it into a signal of the first field and a signal of the second field (one frame is composed of the first field and the second field).

Further, the image signal 41 is input to the analog / digital conversion circuit 37, and the image signal is sampled and A / D converted. The A / D converted image signal is temporarily stored in the field memory 38.
In a normal NTSC signal system, the first field corresponds to an image of odd-numbered scan lines, and the second field corresponds to an image of even-numbered scan lines. The image signal of the first field temporarily stored in the field memory 38 is input to the signal side circuit 39a mounted on the liquid crystal panel 39 corresponding to the odd line, and further, the timing control circuit 3
The timing signal output from the liquid crystal panel 3 is input to the scanning side circuit 39b mounted on the liquid crystal panel 39,
9 displays the image of the first field. Further, the image signal of the second field temporarily stored in the field memory 38 is input to the signal side circuit 40a attached to the liquid crystal panel 40 corresponding to the even lines, and the timing signal output from the timing control circuit 36 is LCD panel 4
It is input to the scanning side circuit 40b attached to 0, and the liquid crystal panel 40 displays the image of the second field. Generally, in the interlace type image signal, so-called interlaced scanning is performed, so that the first field, the second field
The image of the field is displayed on the liquid crystal panels 39 and 4 respectively.
It can be directly assigned to 0.

All or at least a part of the circuit system relating to the image signal generation can be arranged and formed on a single crystal silicon substrate which is the same substrate as the liquid crystal panel, and the device can be downsized. Can be achieved.

[0040]

According to the present invention, a liquid crystal projection type display capable of projecting a high-definition image on a screen with high brightness can be realized, and a large screen display is also possible.

[Brief description of drawings]

FIG. 1 is a structural example of a liquid crystal projection display of the present invention.

FIG. 2 is an explanatory diagram of a screen division example.

FIG. 3 is an explanatory diagram of a configuration example of pixels corresponding to odd lines.

FIG. 4 is an explanatory diagram of a configuration example of pixels corresponding to even-numbered lines.

FIG. 5 is an explanatory diagram of a principle of liquid crystal.

FIG. 6 is an explanatory diagram of the principle of liquid crystal.

FIG. 7 is an explanatory diagram of an embodiment of a control circuit system.

[Explanation of symbols]

1, 2 ... Reflective projection optical system, 3 ... Screen control circuit system, 4
a, 4b, 4c ... Reflective liquid crystal cell, 5 ... Dichroic prism, 6 ... Light source, 7 ... Reflector, 8 ... Condenser lens, 9 ... Projection lens system, 10 ... Internal reflector, 11a, 1
1b, 11c ... Liquid crystal cell, 12 ... Dichroic prism, 13 ... Light source, 14 ... Reflecting mirror, 15 ... Condenser lens, 16 ... Projection lens system, 17 ... Internal reflecting mirror, 18 ...
White projection, 18a ... Red light, 18b ... Green light, 18c ... Blue light, 19 ... Screen, 20 ... Screen before division, 22 ...
Screen after division, 23 ... Screen after division, 24 ... Scan electrode wiring, 24a ... Transistor gate electrode, 25 ... Signal electrode wiring, 26 ... Transistor, 27 ... Pixel electrode, 28a
... Dark part, 28b ... Bright part, 29 ... Scan electrode wiring, 29a ...
Gate electrode, 30 ... Signal electrode wiring, 31 ... Transistor, 32 ... Pixel electrode, 33a ... Dark part, 33b ... Bright part, 3
4 ... Image signal source, 35 ... Synchronous separation signal, 36 ... Timing control circuit, 37 ... A / D conversion circuit, 38 ... Field memory, 39 ... Liquid crystal panel (odd line side), 39a ...
Signal side circuit, 39b ... Scanning side circuit, 40 ... Liquid crystal panel (even line side), 40a ... Signal side circuit, 40b ... Scanning side circuit, 41 ... Image signal, 81 ... Water-soluble polymer, 82
... nematic liquid crystal, 83 ... electric field, 91 ..., polymer layer,
92 ... Nematic liquid crystal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Omura 4026 Kuji Town, Hitachi City, Ibaraki Prefecture Hitachi Research Laboratory, Hiritsu Manufacturing Co., Ltd.

Claims (5)

[Claims] 1. A reflection type optical system having a light source, a condenser lens, a projection lens, and means for demultiplexing and combining the light of the light source for each wavelength band, and a reflection type liquid crystal having a scattering type liquid crystal layer. In a liquid crystal projection display comprising a cell and a screen control circuit for controlling the screen, the reflective liquid crystal cell constituting one screen is divided into a plurality of liquid crystal cell groups, and each liquid crystal cell group is divided into a plurality of liquid crystal cell groups. Correspondingly, a liquid crystal projection display is provided with the reflection type optical system. 2. A reflection type optical system having a light source, a condenser lens, a projection lens, and means for demultiplexing and combining the light of the light source for each wavelength band, and a reflection type liquid crystal having a scattering type liquid crystal layer. In a liquid crystal projection display having a cell and a screen control circuit for controlling the screen, the reflective liquid crystal cells forming one screen are arranged in an array of liquid crystal cells corresponding to the scanning lines of the liquid crystal projection display. A liquid crystal cell row is divided into a first liquid crystal cell group consisting of liquid crystal cell rows corresponding to even-numbered scanning lines and a second liquid crystal cell group consisting of liquid crystal cell rows corresponding to odd-numbered scanning lines, and The first liquid crystal cell group is provided with liquid crystal driving elements at positions corresponding to odd-numbered scanning lines, and the second liquid crystal cell group is provided with liquid crystal driving elements at positions corresponding to even-numbered scanning lines. Each liquid A liquid crystal projection characterized in that the reflection type optical system provided in the crystal cell group synthesizes the images projected by the first liquid crystal cell group and the second liquid crystal cell group to create one screen. Type display. 3. The liquid crystal cell group according to claim 2, wherein the first liquid crystal cell group and the second liquid crystal cell group include a red display liquid crystal cell, a green display liquid crystal cell and a blue display liquid crystal cell, respectively. LCD projection display. 4. The liquid crystal projection type display according to claim 1, 2 or 3, wherein the reflection type liquid crystal cell has a single crystal silicon plate as a substrate and is provided on the substrate together with an active element. . 5. The method according to claim 1, 2, 3, or 4,
A liquid crystal projection display, characterized in that a polymer dispersed liquid crystal is used as the reflective liquid crystal cell.