JPH0356932A - Projection type liquid crystal display device - Google Patents

Abstract

PURPOSE:To suppress the lowering of contrast caused by external light to be low and to obtain a displayed image having high image quality by arranging a specified color filter at a position on a screen corresponding to the picture element of a liquid crystal panel. CONSTITUTION:The specified color filter 5 is arranged at the position on the screen 3 corresponding to the picture element of the liquid crystal panel 4. Therefore, when the displayed image of the liquid crystal panel 4 is projected on the screen 3, the position of the projected picture element of the liquid crystal panel 4 coincides with that of the color filter 5. Then, the projected image is colored by the color filter 5 and the colored image is observed. At such a time, the reflectance of the mask part of the color filter 5 gets low. Thus, the reflection of the external light made incident on the screen from an observation side is suppressed and the high image quality is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a projection type liquid crystal display device that obtains a display image by projecting an image displayed by a liquid crystal panel onto a screen.

[Conventional technology]

FIG. 4 is an optical path diagram of a projection type liquid crystal display device disclosed in, for example, Japanese Unexamined Patent Publication No. 62-28721. In the figure.
(IR). (IG). (IB) is a light source that emits white light, (2R), (2G) . (2B) is a projection lens, (
3) is a screen, (4R). (4G), (4B) are liquid crystal panels that form images, (5R), (5G), (5
B) is a light source (1R). (lG). It is a color filter that converts the white light of (1B) into light of the color of the projected image, where the subscripts (R), (G), and (B) represent the red, green, and blue of the projected image, respectively. It corresponds to a certain extent.

Next, the operation will be explained. The red LCD panel (4R) displays information corresponding to the red portion of the displayed image.
4R) as the transmittance distribution. Light source (IR
) The white light emitted from the red color filter (5
R> is converted into red light, which enters the liquid crystal panel (4R). The light transmitted through the liquid crystal panel (4R) becomes light with an intensity distribution corresponding to the transmittance distribution set on the liquid crystal panel (4R), and this light is projected onto the screen (3) by the projection lens (2R). .

Information corresponding to the green component and blue component of the simultaneously displayed image is also projected onto the screen (3) in the same way as in the case of the red component. In this case, since the same portion of each corresponding color is projected at the same position on the screen (3), the color of the object is reproduced on the screen (3) by additive color mixture.

The viewer observes the image reproduced in this way from the side opposite to the projection side of the screen (3) if the display device is a transmissive type, or from the side opposite to the projection side if the display device is a reflective type. Observe the screen (3) from the projection side.

[Problem to be solved by the invention]

Conventional projection type liquid crystal display devices are structured as described above, and since the image is displayed on the screen, the screen must reproduce all the projected colors, and the color of the screen is white or a reflective color close to it. It was necessary to use a material with a high transmittance or transmittance. Therefore, when external light enters the screen surface from the wl sensing side of the liquid crystal display device,
The intensity of the reflected light reflected to the viewing side is high, and the reflected brightness of the screen is high, which causes problems such as a significant decrease in the contrast of the image displayed on the screen and a significant loss of image quality.

This invention was made to solve the above-mentioned problems, and provides a projection type liquid crystal display device that can maintain high image quality with almost no reduction in image contrast even when external light enters the screen surface. The purpose is to obtain.

[Means to solve the problem]

A projection type liquid crystal display device according to the present invention is a projection type liquid crystal display device that obtains a display image by projecting an image formed by a liquid crystal panel on a screen onto a screen, in which pixels are arranged corresponding to the pixels of the liquid crystal panel. A predetermined color filter is placed at the position of the screen.

[For production]

In the projection type liquid crystal display device of the present invention, the pixels of the liquid crystal panel and the color filters provided on the screen are provided at corresponding positions, so that when the displayed image on the liquid crystal panel is projected onto the screen, the projected The pixels on the LCD panel and the color filters match. For this reason, the projected image is colored by a color filter, and the colored image is
be done.

At this time, by lowering the reflectance of the mask portion of the color filter, reflection of external light that enters the screen from the detection side can be suppressed, and high image quality can be obtained.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an optical path diagram showing a projection type liquid crystal display device according to an embodiment, FIG. 2 is a front view of a liquid crystal panel, and FIG. 3 is a front view of a color filter. In the figure, (1) is the light J that emits white light.
．． (2c) is a collimation lens that converts the light from the light source (1) into parallel light, and is arranged facing the light source (1). (2p) is a projection lens, which is arranged opposite to the screen (3). (4) is a liquid crystal panel that forms a display image, and is arranged between the collimation lens (2c) and the projection lens (2p). (5) is a color filter that colors the image projected on the screen (3) in a predetermined manner, and is arranged on the viewer (6) side of the image on the screen (3).

In FIG. 2, the liquid crystal panel (4) has a large number of liquid crystal pixels (7) arranged in a uniformly distributed manner in a matrix, so that a display image is formed as a whole. The liquid crystal pixel (7) is a liquid crystal monochrome pixel (7R) that displays brightness information of red, green, and blue components, respectively. (7G) and (7B) are arranged adjacently in a mosaic pattern. In Figure 3, (
8) are filter pixels arranged on the color filter (5), (8R) . (8G) and (8B) constitute the filter pixel (8), and are filter single-color pixels that color and display red, green, and blue information of the displayed image, and are colored red, green, and blue, respectively. has been done. These filter pixels (8), filter single color pixels (8R), (8G
), (8B) are each liquid crystal pixel (7) of the liquid product panel (4), liquid crystal car color pixel (7R), (7G), (7B), respectively.
is placed in a position corresponding to (9) is a mask portion formed between adjacent filter pixels (8) on the color filter (5) to prevent light from passing through.
It is colored black.

Next, the operation will be explained. First, display image information is set on the liquid crystal panel (4). This display image information setting involves breaking down the display image into minute elements, finding the intensities of red, green, and blue light necessary to reproduce the colors of those elements, and then setting the information corresponding to the intensities of these lights. Transmittance is calculated using liquid single color pixel (7R
), (7G), and (7B). The white light emitted from light g(1) becomes parallel light from the collimation lens (2c), and the liquid crystal panel (
4).

As mentioned above, the liquid crystal panel (4) has liquid crystal monochrome pixels (7
Since the display image information is set as the transmittance of R), (7G), and (7B), the parallel light has a light intensity distribution that corresponds to the transmittance distribution of the liquid crystal panel (4), and the projection lens (
2p), the image is enlarged and projected onto the screen (3). The color filter (5) is screen IJ-n (3) (7) [? N person (
The image projected onto the screen (3) passes through the screen (3) and the color filter (5) and is viewed from the viewer (6) side. Here, the projected image of the liquid crystal pixel (7) on the screen (3) is adjusted to the focal length of the projection lens (2P) and the projection distance (projection lens (2P)) so as to match the position of the corresponding filter pixel (8).
Projection conditions such as the distance between p) and the screen (3) are selected. For example, the image of a liquid crystal pixel (7a) at a specific position on the screen (3) and the filter pixel (8a) at a corresponding position are at the same position when viewed from the viewer (6) side. , liquid crystal monochrome pixels according to the above transmittance distribution (
7R), (7G), and (7B) are filter monochromatic pixels (8R) and (8G) at corresponding positions, respectively.
, (8B), and the image is displayed on the viewer (6) side. If this image is observed from the position of the observer (6) who is a predetermined distance away from the screen (3), the colored monochromatic pixels will undergo additive color mixing, and vA can be observed as an image.

At this time. Screen (3) from the lf51 observer (6) side
Even if external light is incident on the color filter (5), the reflectance of the mask portion (9) of the color filter (5) is very low, so there is almost no increase in reflected brightness due to external light, resulting in a high-contrast, high-quality image. is obtained.

In addition, in the liquid crystal panel (4), as shown in FIG.
There is a portion where the transmittance is not controlled. If the position on the color filter (5) corresponding to this part is used as a mask part (9) and the reflectance is set very low (in this example, it is colored black), the reflected brightness due to external light can be reduced. The rise is further suppressed, and high-contrast, high-quality images can be obtained.

In the above embodiment, the projection side is on the opposite side to the viewer (6) with respect to the screen (3), but even if the projection side and the viewer (6) are on the same side, Color filter (5) is II! If it is arranged on the detection side (6) side, the same effects as in the above embodiment can be achieved.

In addition, the liquid crystal pixel (7) and the filter pixel (8) are configured by arranging monochromatic pixels in a stripe pattern, and the liquid crystal pixel (
7) and the filter pixels (8) are arranged in a grid pattern, but other pixel arrangements, such as a delta arrangement in which monochromatic pixels are arranged in a triangular shape, are also possible.

〔Effect of the invention〕

As described above, according to the present invention, predetermined color filters are arranged at the positions of the screen corresponding to the pixels of the liquid crystal panel, so that the reduction in contrast due to external light is suppressed to a very low level, and high-quality displayed images can be obtained. There is an effect that can be obtained.

[Brief explanation of drawings]

Fig. 1 is an optical path diagram showing a projection type liquid crystal display device according to an embodiment of the present invention, Fig. 2 is a front view of the liquid crystal panel, Fig. 3 is a front view of a color filter, and Fig. 4 is a conventional projection type liquid crystal display. FIG. 2 is an optical path diagram showing a display device. In each figure, the same reference numerals indicate the same or corresponding parts, (3)
is a screen, (4) is a liquid crystal panel, (5) is a color filter, (6) is an i-celebrator, (7) is a liquid crystal pixel, and (8) is a filter pixel.

Claims (1)

[Claims] (1) In a projection type liquid crystal display device that obtains a display image by projecting an image formed by a liquid crystal panel on which pixels are arranged onto a screen, a predetermined position is placed on the screen corresponding to the pixel of the liquid crystal panel. A projection type liquid crystal display device characterized by disposing color filters.