JPH03219789A - Liquid crystal projector - Google Patents

Abstract

PURPOSE:To obtain a picture with high resolution by using a liquid crystal panel for odd number field and even number field. CONSTITUTION:A same video signal and a shift pulse are fed to horizontal drivers 24, 25, and sampled one by one line each. In the case of an odd number field, a shift pulse is applied only to a vertical driver 22 and each line of a liquid crystal panel 16i is selected one by one each and a sampled signal of odd number field is supplied. In the case of an even number field, a shift pulse is applied only to a vertical driver 23 and a signal of an even number field is fed to a liquid crystal panel 17i. Moreover, sample clocks with different phase by 180 deg. are given to shift registers of the drives 24, 25. Since the vertical resolution is doubled in this way, the deficient brightness of the screen due to the reduction in the aperture rate is avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a liquid crystal projector using a liquid crystal display panel.

BACKGROUND OF THE INVENTION Conventionally, a liquid crystal projector using a liquid crystal display panel is disclosed in Japanese Patent Application Laid-Open No. 1983-150487.

The optical system of the above-mentioned liquid crystal projector is as shown in FIG.

In the same figure, a light source (1) containing three primary colors (RSG, B)
After the light other than visible light is removed by a UV filter (2), the light is supplied to a B dichroic mirror (3) that reflects only blue light, and the blue light is separated.

The light transmitted through this B dichroic mirror is supplied to the IG dichroic mirror (4) which reflects only green light, and is separated into green light and red light.

The blue light is reflected by a reflecting mirror (5), then condensed by a condenser lens (6), and supplied to a B liquid fixture panel (7). Further, the green light is collected by a condenser lens (8) and supplied to the G liquid fixture panel (9). Furthermore, red light is also condensed by a condenser lens (10) and supplied to the G liquid fixture panel (11). Then, the blue light and green light whose brightness is modulated by the video signal in the B and G liquid device panels (7) and (9) are sent to the second G dichroic mirror (12).
is synthesized with In addition, the red light whose brightness is modulated by the R liquid equipment panel (11) is reflected by the reflection mirror (13), and then
The R dichroic mirror (14) combines the blue and green lights. Furthermore, this combined light is passed through the projection lens (
15) on a screen (not shown).

The vertical resolution of the above LCD projector is determined by the number of pixels in the vertical direction of the LCD panel, but current LCD panels are 240 pixels (vertical direction) x 320 pixels (horizontal direction).
The mainstream was moderate.

Therefore, there is a drawback that an image with 525 scanning lines of the current NTSC system cannot be reproduced.

(c) Invention tries to solve the problem! ! SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to provide a liquid crystal projector that can obtain good vertical and horizontal resolution even when using a liquid crystal panel with a limited number of pixels.

(d) Means for Solving the Problems The present invention includes a light source that emits light of at least three components of red, green, and blue, and a plurality of separation devices that separate the light from the light source into the three components of red, green, and blue. A dichroic mirror is inserted into each of the optical paths of the three separated red, green, and blue components, and the three components are separated according to the red, green, and blue primary color signals obtained by sampling the video signal of the odd field. a plurality of first liquid crystal panels that modulate component light, and a plurality of second liquid crystal panels that modulate the three component lights, respectively, according to red, green, and blue primary color signals obtained by sampling even field video signals. The present invention is a liquid crystal projector that includes a liquid crystal panel and a plurality of synthesis dichroic mirrors that synthesize three components of light that have passed through the first and second liquid crystal panels.

(E) Function By using liquid crystal panels for odd and even fields, the horizontal or vertical resolution can be doubled.

(f) Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the optical system of the liquid crystal projector in this embodiment, and the same parts as in FIG. 7 are given the same reference numerals and explanations are omitted.

The light from the light source (1) is split into two identical beams containing three primary colors by a half mirror (18) and a reflecting mirror (19), and a first optical system (16) for odd fields and a first optical system for even fields. 2 optical system (17).

The first and second optical systems (16) and (17) are completely the same, and each optical system is the same as the conventional optical system shown in FIG.

In the case of an odd field, the liquid crystal panel of the first optical system (
R, G, and B primary color signals obtained by sampling video signals of odd fields are supplied to 16e), 16g, and 16i respectively, and during even fields, liquid crystal panels of the second optical system (17e) and 17g are supplied. (17i) are supplied with R, G, and B primary color signals obtained by sampling the even field video signal, respectively.

Therefore, the image information synthesized by the first and second optical systems (16) and (17) becomes as shown in Fig. 2 (a) and (b), respectively.
These are the half mirror (20) and the reflective mirror (21)
The combined and projected image looks like the one shown in Figure 2 (C).

Note that the liquid crystal panels of the first and second optical systems are installed with a relative shift of one line.

Next, the drive circuit for the liquid crystal panel in this embodiment will be explained with reference to FIG.

FIG. 3 shows only the R liquid crystal panels of the first optical system and the second optical system, and the same applies to the other G and B liquid crystal panels.

In the figure, each liquid crystal panel (16i) (17i) has 240 pixels in the vertical direction, and each has a vertical driver (22) (23) consisting of a shift register, a shift register and a sample hold circuit, respectively. horizontal drivers (24) and (25).

The same video signal and shift pulse are supplied to the horizontal drivers (24) and (25).
Sampled line by line.

Then, in the case of an odd number field, a shift pulse is applied only to the vertical driver (22), each line of the liquid crystal panel (161) is selected one by one, and the signal of the sampled number field is supplied. Sail-ru.

In the case of an even field, the shift L-pulse is applied only to the vertical driver (23), and similarly, the shift L-pulse is applied to the vertical driver (23).
) is supplied with an even field signal.

According to this embodiment, the vertical resolution is twice that of the i-prompt example.

Next, other embodiments of the drive circuit will be described with reference to FIGS. 4 to 6.

In Figure 4, horizontal drivers (2
4) Each shift register in the horizontal driver (25) for the coefficient field is given a sampling clock having a phase difference of 180''.

That is, when video signals such as (a), ())) are sampled using the sampling clocks shown in FIGS. 5(b) and (d), respectively, the images sampled during odd and even fields are It will look like Figure 6 (a) and (b).

Therefore, when these are temporally combined, it becomes as shown in FIG.

(1.) Effects of the invention - L description! In<240 in the vertical direction according to the invention
Even a liquid crystal panel as small as a pixel can display a full line interlaced display using the current NTSC system, making it possible to obtain 4L images with high resolution.

In addition, a liquid crystal panel with approximately 500 pixels in the vertical direction is used.
The present invention can also be applied to an I-ID TV with 1125 scanning lines.

In addition, insufficient brightness of the screen caused by reduction in aperture ratio due to signal lines, scanning lines, TPT, etc. of the panel can be resolved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an optical system according to an embodiment of the present invention;
Figures 2 (a), (0), and ()) are diagrams showing the first optical system, second optical system, and images after composition, respectively, and Figure 3 is a diagram showing the driving circuit of the liquid crystal panel in this embodiment. It is. FIG. 4 is a diagram showing another embodiment of the drive circuit, FIG. 5 is a Hasugi diagram of the main part thereof, and FIG. 6 is an operation explanatory diagram. Moreover, FIG. 7 is a diagram showing a conventional optical system. (1)...Light source, (16)...First optical system, (17
)...Second optical system, (22)(23)...Vertical driver, (24)(25)...Horizontal driver

Claims (1)

[Claims] (1) a light source that emits light of at least three components of red, green, and blue; a plurality of separation dichroic mirrors that separate the light from the light source into the three components of red, green, and blue; and the separated red, A plurality of first lights are inserted into each of the optical paths of the three green and blue components and modulate the three components of light in accordance with the red, green and blue primary color signals obtained by sampling the video signal of the odd field. a liquid crystal panel, a plurality of second liquid crystal panels that respectively modulate the three component lights according to primary color signals of red, green, and blue obtained by sampling an even field video signal; A liquid crystal projector that includes a plurality of synthesis dichroic mirrors that synthesize three components of light that have passed through a liquid crystal panel. (2) The liquid crystal projector according to claim 1, wherein a sampling clock for sampling the video signal of the odd field and a sampling clock for sampling the video signal of the even field have a phase difference of 180 degrees from each other.