JPH0478293A - Liquid crystal projection display device - Google Patents

Abstract

PURPOSE:To realize a 3-board type liquid crystal projector with small size, light weight and high performance by providing an optical distortion correction means projecting a picture with a different aspect ratio with magnification with respect to an aspect ratio of a picture formed by an incident light to the display device. CONSTITUTION:An M-NTSC picture is displayed on a liquid crystal module and after the center of the display picture is matched in the middle of an optical means correcting longitudinal contraction, the longitudinal contraction is corrected by an optical correction means to display the resulting picture in the regular state. The M-NTSC picture displayed on a liquid crystal display module for B/G-PAL.SECAM display is displayed in the middle of a screen while the longitudinal contraction is corrected.

Description

[Detailed Description of the Invention] [Object of the Invention] (Field of Industrial Application) The present invention belongs to the field of projection display devices that optically enlarge and display color television images, and in particular, a projection display device that uses a liquid crystal module. The present invention relates to a liquid crystal projection display device.

(Prior Art) Conventionally, front type projection television receivers (hereinafter referred to as liquid crystal projectors) using liquid crystal modules have been commercially available. In addition to the front type, there are rear type LCD projectors.

A liquid crystal projector is characterized by being smaller and lighter than a projector using a projection type cathode ray tube (hereinafter referred to as a CRT projector).

There are several technical points to realize in order to realize a liquid crystal projector.

■Brightness: All you have to do is increase the light transmittance of the liquid crystal module, and if you increase the brightness of the lamp that illuminates the liquid crystal module from behind, the brightness on the screen will become brighter. However, liquid crystal modules have a problem with light resistance (heat resistance), and cannot be exposed to very strong light. In other words, when the temperature rises, the liquid crystal undergoes a transition and is no longer able to perform its function.

■Color shift of three colors: In the case of a three-panel type like a CRT projector, three liquid crystal modules and lenses for R (red), G (green), and B (blue) are arranged side by side. At this time,
When three-color images are formed on a screen, it is difficult to focus them on the same point, and the three-color images cannot be completely combined on the screen, resulting in color shift.

■Thin type: In the case of a rear type projector, it is particularly required to be thin and lightweight, which is a major feature compared to a CRT projector.

(Problems to be Solved by the Invention) Conventionally, liquid crystal 70 diectors have had the technical points (1) to (4) as described above.

Therefore, it is an object of the present invention to provide a small, lightweight, and high-performance liquid crystal projection display device that can improve the above-mentioned technical points and take advantage of its features.

[Structure of the Invention] (Means for Solving the Problems) A first invention related to this liquid crystal projection display device includes a spectroscopic means for separating white light into three primary color lights, and a plurality of light beams from the spectroscopic means are incident. a liquid crystal module for forming an image of each primary color; and an optical system for inputting light transmitted through each of the liquid crystal modules and projecting the image on a screen in an enlarged manner for display, the optical system comprising: The apparatus is characterized in that it includes an optical distortion correction means for enlarging and projecting an image at a different aspect ratio than the aspect ratio of the image formed by the incident light. .

Further, a second invention provides a liquid crystal projection type in which white light is separated into three primary color lights, each of which enters a liquid crystal module, and the light transmitted through each of the liquid crystal modules is enlarged and projected by an optical system for display. In the display device, each of the liquid crystal modules has an image display section and a drive circuit section and are arranged in a line, and the image display section of the central liquid crystal module is provided in the center of the module, and the image display section of the peripheral liquid crystal module is The image display section is provided eccentrically to the side of the central liquid crystal module, the drive circuit section of the center liquid crystal module is provided symmetrically to the area other than the image display section, and the drive circuit section of the peripheral liquid crystal modules is provided eccentrically toward the image display section. It is characterized by being provided at a position offset from the other parts.

Furthermore, a third invention is a liquid crystal projection type in which white light is split into three primary color lights, each of which enters a liquid crystal module, and the light transmitted through each of the liquid crystal modules is enlarged and projected by an optical system for display. In the display device, the white light generating means is characterized by comprising a lamp that generates an arc in a downward direction, and a reflector that reflects the light from the lamp.

(Function) According to the first invention, it is possible to increase the light transmittance and increase the brightness. For example, since a vertically stretched image is shrunk and projected on a screen, the density of light becomes higher and brighter at the top and bottom of the screen.

According to the second aspect of the invention, the liquid crystal modules on both sides can be decentered toward the center with respect to the center of the projection lens, so that the width occupied by each module can be reduced. Therefore, color shift among the three colors can be eliminated.

According to the third invention, by generating the arc of the light source lamp in the downward direction, it is possible to stably generate the arc.

(Example) Examples will be described with reference to the drawings.

1 and 2 show a first embodiment of the present invention. As mentioned above, it is necessary for liquid crystal modules to increase light transmittance. On the other hand, as is well known, there is a tendency for picture elements to become more and more segmented and increased in order to improve image quality, which is inconsistent with increasing light transmittance. In this embodiment, the liquid crystal module is square or slightly elongated. In other words, in the case of a conventional direct-view LCD television, the LCD module has an aspect ratio of 43, which is the same as the aspect ratio of the television broadcast picture, as shown in Figure 1(a).
However, in the present invention, for example, the shape shown in Fig. 1 (
As shown in b), the aspect ratio of the liquid crystal module is 1,
Set to 1. As a result, the area of each picture element becomes larger on the vertical side, and the aperture ratio, that is, the light transmittance of the liquid crystal module can be increased.

However, when an image is displayed on such a liquid crystal module with an aspect ratio of 1:1, the image becomes longer than the original image. Therefore, in this embodiment, as shown in FIG. 2, the optical system is further provided with an optical distortion correction means having the characteristic of returning a vertically elongated screen to a normal screen.

FIG. 2(a) shows the principle. That is, by vertically shrinking a vertically long image displayed on a liquid crystal module with an aspect ratio of 1:1, the aspect ratio returns to a normal image with an aspect ratio of 4.degree. FIG. 2(b) shows an example in which a special lens that causes vertical contraction is used as a means for this purpose.

Further, as shown in FIG. 2(C), a similar vertical shrinkage correction can be easily performed using a vertical shrinkage reflecting mirror made of a concave mirror. In Fig. 2(b), the vertical direction of the image obtained through the liquid crystal module of Fig. 1(b) is abc
The image projected through the vertical contraction lens is a'
Vertical shrinkage occurs as shown in b'c'. Similarly, in Fig. 2 (C), the image <a, b, c) is a'
It is projected vertically compressed as shown in b'c'. In addition to the above effects, this embodiment also has the following effects.

That is, in the case of a rear-type liquid crystal 70 diector, the brightness of the screen on the screen is the brightest at the center and dark at the periphery. However, in this embodiment, since a vertically long image is compressed on the screen, the density of the amount of light is naturally higher at the upper and lower parts of the screen than at the center, and this defect is corrected. Furthermore, since the optical lens and the light source (lamp holder) are usually circular, it is natural that the liquid crystal module should be more square than horizontally elongated in terms of effective use of light.

Fig. 3 shows a color liquid crystal projection display device using the liquid crystal module shown in Fig. 1 and the optical distortion correction means shown in Fig. 2. This example shows an example of a liquid crystal projector that can be placed side by side (in the same direction) and synthesize a three-color picture on the screen. In Figure 3, (a) is a perspective view of the main parts of the liquid crystal projector, (b)
) is a top view showing the basic configuration of the liquid crystal 10 diector, (C)
1 is a side cross-sectional view of a liquid crystal projector configured in a rear type. In FIGS. 3(a) and (b), the light source 1
The beam of light is reflected by the freta 2 and becomes a parallel beam of light, which is red,
The blue and green dichroic mirrors 3.4.5 separate the light into three primary color lights, and each color light enters a liquid crystal module 6.7.8 via a field lens. As described in FIG. 1(b), the liquid crystal module 6.7.8 is a module with an asvection ratio of 1 to 1:1. Furthermore, the light transmitted through the liquid crystal module 6.7.8 is transmitted through the projection lenses 9 and 10.1.
1 onto the screen 12. The projection lens 9.1.0.11 includes a vertical contraction lens based on the principle shown in FIG. 2(b).

Figure 3 (C) shows the first LCD module as liquid crystal module 6.7.8.
Using the shape shown in figure (b), the projection speed is 010.11.
is the same as before. and projection lens 9,
10.11 is reflected by mirror 13.14 and projected onto screen 12.
), which uses a vertically contracted reflector based on the principle shown in
All the members are housed in a housing 15 to constitute a rear type liquid crystal projector.

Furthermore, by applying the above-mentioned optical distortion correction means,
Furthermore, it becomes possible to apply it to other uses. FIGS. 4 to 6 illustrate cases in which a liquid crystal projector receives broadcasts of different systems. As is well known, the current representative broadcasting systems in the world are M-NTSC and B/G-P.
There are three types: AL and SECAM, and the number of vertical scanning lines is a particularly important factor depending on the liquid crystal system.

M-NTSC is 525 lines (262,5 lines/field)
, B/G-PAL-SECAM is 625 (3T2.
5 lines/field), when using a CRT,
By changing the vertical scanning beam speed, the vertical amplitude can be electrically set freely according to the method.
When using a liquid crystal, the number of pixels in the vertical direction is physically fixed, which causes problems.

Currently, about 9 of the liquid crystal modules for B/G-PAL-SECAM display (vertical pixel count is 312.5 lines/field)
If an M-NTSC signal is displayed on approximately 0% (corresponding to the effective image) (for example, 276 lines), the image will be vertically shrunk as shown in FIG. Because,
This is because M-NTSC only transmits 265.2 signals/field. In other words, in Figure 4,
13.5 of the scanning lines constitute an invalid display section.

Therefore, by applying the above-mentioned optical distortion correction means, correction can be performed as shown in FIG. The example shown in this figure is B/G-
This is an embodiment in which an M-NTSC image displayed on a liquid crystal module for PAL-SECAM display is displayed at the center of the screen with vertical shrinkage corrected.

In the example shown in Fig. 5, first, an MNTSC image is displayed on a liquid crystal module with 276 scanning lines as shown in Fig. 5(a), and then the displayed image is displayed as shown in Fig. 5(b). After aligning the center with the center of the optical means for correcting vertical shrinkage (this can be done by changing the angle of the mirror 13 in Figure 3, etc.), it becomes vertically elongated as shown in Figure 5 fc). The vertical shrinkage is corrected using an optical correction means such as the above, and the image is displayed on the screen in its normal state. Figure 2(a) shows an example of shrinking a vertically stretched image, but Figure 5 shows an example of stretching a vertically compressed image, and the incident side in Figures 2(a) and (b) This can be achieved by reversing the emission side.

Furthermore, an example as shown in Fig. 6 is also possible, and B/G-P
It is also possible to display an M-NTSC image displayed on a liquid crystal module for AL SECAM display at the center of the screen with vertical shrinkage corrected.

As shown in FIGS. 6(a) to (C), align the center of the displayed image (that is, the NTSC image in FIG. 6(b)) with the center of the optical system, and increase the magnification of the optical system to 5. Only the valid display area is displayed on the screen, making it a regular display image. Note that the centering means can be electrically realized by a circuit that controls the driver IC of the liquid crystal module.

In this way, the display screen on the screen is
Also in the case of SC, BG-,...,P A 1. ,,−
The same can be said for SE CA Pvl.

FIG. 7 is for explaining a second embodiment of the present invention. In this figure, the projection lens 9 in FIG.
, 10.11 and the liquid crystal module 67.8. As is well known in CRT blocker technology, in the three-lens system, the image distortion of the three colors is optically different when the images are combined on the screen. The image is electrically distorted. However, in the case of a liquid crystal projector, electrical forward/reverse correction is difficult, so as shown in FIG.
, 8a < in the case of Fig. 4, the projection lens 9,
The images are eccentric to the right and left with respect to the center of the screen 11, so that the left and right (red and green) images coincide with the center (blue) image on the screen 12. If they do not match, the colors will be faded. Note that 7a indicates a display section of the liquid crystal module 7.

Therefore, it is better that the width (outer dimensions) of the liquid crystal module be as narrow as possible. If the width is wide, three projection lenses 9
．． 10.1.1 needs to be widened, the above-mentioned optical distortion becomes large, and in order to correct this, the above-mentioned eccentricity of the liquid crystal module to the right and left becomes large, and as a result, the lens diameter increases. It is necessary to increase the size, which makes it expensive. As is well known, the liquid crystal module includes a driver IC 1 for controlling the driver ICs (horizontal and vertical driver ICs) and other circuits arranged around the main body to drive the liquid crystal main body (display section). Although a circuit section is required, by appropriately arranging the driver circuit section, the external shape (width, height) of the liquid crystal module can be designed with some degree of freedom.

FIGS. 8 to 10 show a second embodiment of the present invention based on the idea described above.

Figure 8 shows that in order to narrow the width of the three liquid crystal modules, the driver circuit section (shaded area) for the display sections 6a, 7a, 8a is bent integrally with the surface of the display section and is provided at a position f. This is an example. By doing so, the width of the liquid crystal module viewed from the light incident side can be made smaller than in the past.

Figure 9 shows the left LCD module 6 and the right LCD module 8.
This is an embodiment in which the display sections 6a and 8a are respectively shifted toward the center by tL, and the position of the driver circuit section is changed.

FIG. 10 specifically shows the arrangement of driver circuits, etc. in the liquid crystal module of FIG. 9.
In (b), the liquid crystal module 2o has a display section 20a.
and the X driver IC21 and Y driver IC in the surrounding area.
22 and a control circuit 23. In FIG. 10(a), the Y driver ICs 22 are arranged in rows on the side of the module 20, and the control circuit 23 is arranged at the top (or bottom). In FIG. 10(b), a part of the Y driver IC 22 is placed at the top or bottom of the module 20. In this way, by changing the position of the display section 20a and arranging the driver circuit section appropriately, the l'mi of each display section of the three liquid crystal modules can be brought closer to each other.
can be filled.

Fig. 71 is a modified embodiment of Fig. 9.6 In Fig. 9, the three liquid crystal modules on the left, right, and center are 3M's liquid crystal modules with an arrangement n4 structure. In FIG. 11, one type of liquid crystal module is prepared. That is, three liquid crystal modules 6.7.8
Liquid crystal modules with the same structure were used, and either left or right was configured so that one liquid crystal module 8 (or 6) was turned upside down with respect to the other two liquid crystal modules 6.7 (or 8, 7) to allow light to enter. It is something. However, as a result, if light continues to enter the liquid crystal module from the back side, the image will be a left-right reversed image, so this is corrected by electrically driving the left-right reverse in the driver circuit section.

Next, a third embodiment of the present invention will be described.

As the light source 1 in FIG. 3, a metal halide lamp or a halogen lamp is used. Both methods generate light by generating arc discharge inside an arc tube filled with a luminescent substance. It is necessary to condense the light beam of the lamp 1 into parallel light by the deflector 2, and therefore it is desirable to use a point light source as stable as possible. On the other hand, it has been found that the arc of lamp 1 is more stable if it is generated in the direction of gravity.

A stable arc also extends the life of the lamp.

FIG. 12 shows a third embodiment of the invention. When the projection lenses 9, 10° 11 are arranged horizontally as shown in Fig. 3(a), it is easy to consider structurally that the lamp 1 is also arranged horizontally. I have an arc problem. Therefore, in the embodiment shown in FIG. 12(a), unlike the case shown in FIG. The light is reflected by the mirror 30 and enters the dichroic mirror 3.4.5. If this mirror 30 is a so-called cold mirror (does not reflect infrared rays) type, it is possible to prevent heat that adversely affects the operation of the liquid crystal module 6.78. If we try to prevent this heat due to infrared rays in the complement of Figure 3(a),
It is necessary to make the entire reflector 2 a cold mirror, which is expensive, but in Fig. 12(a), the small flat mirror 3
If only 0 is used as a cold mirror, the cost can be reduced.

FIG. 12(b) shows an enlarged view of the lamp 1 in FIG. 12(a). The lamp 1 is, for example, a metal halide lamp, and there is an electric lamp 1 inside the luminous tube, both ends of which are connected to lead wires.
1a and lb are arranged, and when the electrodes 1a and lb are lit, an arc is generated between the electrodes 1a and lb, and light is emitted.

FIG. 13 shows a modification of the third embodiment. In the embodiment shown in this figure, the lamp 1 is arranged vertically,
Projection lens 9.10, 11, liquid crystal module 6.7, 8
, and a projection lens 9.1011 are arranged in the vertical direction.

In this arrangement, since the aspect ratio of the main body (display section) of the liquid crystal module is 4:3 and short in the vertical direction for normal television signals, the three projection lenses 9, 10, . 11 can be placed closer together than in the horizontal arrangement of the projection lenses in FIG. 3, and color shift can be minimized.

Next, referring to the above-mentioned FIGS. 3 and 12, red.

The arrangement of blue and green (R, B, G) will be explained.

As is well known, there is an optimum white color temperature for making the colors of an image appear most natural. A normal television receiver is set to 9000K to 10000K. Therefore, it is only necessary to set the same for LCD projectors.The white color temperature of LCD projectors is mostly determined by the characteristics of the lamp.Currently, metal halide lamps are commonly used as lamps, but this The lamp has excellent color rendering properties among various types of lamps, and a white color temperature of approximately 7000 K° has been achieved even when other characteristics such as lifespan are considered. However, there is a drawback that green is a little too strong compared to red and blue light.

Figures 3 and 12 are based on the above characteristics of the lamp.
The arrangement of R, B, and G is determined. As can be seen from these figures, the light transmittances of the R, B, and 03 sets of optical systems are not completely the same, and there is always a system with the lowest light transmittance. In FIGS. 3 and 12, the optical system on the right side, which has the longest optical path, has the lowest light transmittance. Therefore, when using a metal halide lamp, the green color is strong, so if you use a system with the lowest light transmittance for green color, the above-mentioned drawbacks will be corrected and you can realize a liquid crystal 10 diector with a more natural color. .

[Effects of the Invention] As described above, according to the present invention, a compact, lightweight, and high-performance three-panel liquid crystal projector is realized by improving the technical problems of the liquid crystal module and taking advantage of the characteristics of the liquid crystal module. I can do that.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of a liquid crystal projection display device according to the present invention, and FIG. 1 and 2 are conceptual diagrams,
Fig. 3 is an explanatory diagram showing a specific configuration, Figs. 4 to 6 are explanatory diagrams showing an application example of the first embodiment, and Figs.
1 shows the second embodiment of the present invention, FIG. 7 is a basic explanatory diagram, FIGS. 8 to 11 are explanatory diagrams showing specific examples, and FIG. 12 is a third embodiment of the present invention. Explanatory diagram showing an example, 1st
FIG. 3 is an explanatory diagram showing a modification of the third embodiment of the present invention. 2... Reflector, dichroic mirror liquid crystal module, 8a... Liquid crystal main body (display part) 11... Projection lens, lean. 1... light source, 3, 4. 5 6 7, 8... 6a 7a 9, No. 12...Suf γ 唖x+y! 1: ) Figure 10B Figure 1 (0) I! l [Fig. 7 (b) Front view Fig. 13 (0) Oblique view (b) Rania ore thickness Fig. 12

Claims (6)

[Claims] (1) A spectroscopic device that separates white light into three primary color lights, a liquid crystal module that receives each light from the spectroscopic device and forms an image of each primary color, and a liquid crystal module that separates the light that has passed through each of the liquid crystal modules. An optical system for enlarging and projecting an image onto a screen when the incident light is incident on the screen. A liquid crystal projection type display device comprising: an optical distortion correction means as described above; (2) In each of the liquid crystal modules, the shape of the image display section is vertically longer than the aspect ratio of a television broadcast image, and the optical distortion correction means is configured to adjust the aspect ratio of the image formed by the incident light. 2. A liquid crystal projection type display device according to claim 1, wherein an image is enlarged and projected with a reduced aspect ratio in the vertical direction. (3) In each of the liquid crystal modules, the shape of the image display section has the same aspect ratio as the aspect ratio of a television broadcast image, and the image is shrunk in the vertical direction in advance, and the optical distortion correction means is configured to 2. The liquid crystal projection type display device according to claim 1, wherein the image is enlarged and projected at an aspect ratio that is vertically expanded relative to the aspect ratio of the image formed by the incident light. (4) A liquid crystal projection type display device in which white light is split into three primary color lights, each of which enters a liquid crystal module, and the light transmitted through each of the liquid crystal modules is enlarged and projected using an optical system for display, 1. A liquid crystal projection display device, wherein each liquid crystal module has an image display section and a drive circuit section, and the drive circuit section is formed by bending the drive circuit section with respect to the surface of the image display section. (5) In a liquid crystal projection type display device in which white light is split into three primary color lights, each of which enters a liquid crystal module, and the light transmitted through each of the liquid crystal modules is enlarged and projected using an optical system for display, Each liquid crystal module has an image display section and a drive circuit section, and is arranged in a line.The image display section of the central liquid crystal module is provided at the center of the module, and the image display sections of the peripheral liquid crystal modules are located at the center. The driving circuit section of the central liquid crystal module is arranged symmetrically on the part other than the image display section,
A liquid crystal projection display device characterized in that a drive circuit section of a peripheral liquid crystal module is provided at a position offset from a portion other than an image display section. (6) A liquid crystal projection type display device in which white light is split into three primary color lights, each of which enters a liquid crystal module, and the light transmitted through each of the liquid crystal modules is enlarged and projected using an optical system for display, A liquid crystal projection type display device, characterized in that the white light generating means comprises a lamp that generates an arc in a downward direction, and a reflector that reflects light from the lamp.