JPH0836224A - Projection display device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a projection display device in which moire is inconspicuous and good image quality can be obtained. A screen 6 having a lenticular lens 5 having a periodic structure in one direction, a light valve 2 having pixels arranged in a matrix, a light source 1 for illuminating the light valve 2, and an output from the light valve 2. A projection lens 3 which receives light and projects an optical image of the light valve 2 onto the screen, and the periodic structure on the surface of the lenticular lens 5 is larger than the pitch of the periodic structure of the lenticular lens 5 of the screen 6. The image pitch of pixels in the direction corresponding to is in the range of 2.6 to 3.6 times or 4.5 times or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device which illuminates an optical image formed on a light valve with illumination light and projects it on a screen through a projection lens.

[0002]

2. Description of the Related Art In order to display an image on a large screen, an optical image corresponding to an image signal is formed on a small light valve, and the optical image is irradiated with illumination light and enlarged on a screen through a projection lens. A projection display device for projecting has been developed. A CRT has been conventionally used as the light valve, but recently, a liquid crystal panel in which pixels are arranged in a matrix is often used. There are line type and delta type matrix arrangements. FIG. 2 shows a schematic diagram of the pixels 7 arranged in the line type, and FIG. 3 shows a schematic diagram of the pixels 7 arranged in the delta type. Further, as the rear projection type screen, a two-panel type screen using a combination of a Fresnel lens and a lenticular lens is generally used.

FIG. 1 shows the configuration of a rear projection display device using the above-mentioned two-panel rear projection screen. A light valve 2 composed of a liquid crystal panel is illuminated by an irradiation system 1, and an optical image on the liquid crystal panel is magnified by a projection lens 3 to form an image on the surface of a two-element screen 6 composed of a Fresnel lens 4 and a lenticular lens 5. To be done.
The Fresnel lens 4 has a function of directing the incident light in the direction in which the observer is positioned, and the lenticular lens 5 has a function of dispersing the light emitted from the Fresnel lens 4 into appropriate angles in horizontal and vertical directions at an appropriate ratio. Have.

By the way, when the pixels of the light valve 2 are arranged in a matrix, the image enlarged and formed on the screen 6 also forms a matrix image, and the pixels are arranged in a delta type. Since the formed image also forms a delta type image, when pixels in the matrix type and delta type arrangements and the lenticular lens 5 both have a periodic structure in the horizontal direction, moire occurs in the horizontal direction. To do. Techniques have been developed to prevent the projected image on the screen from being difficult to see due to this moire, and to make the moire less noticeable. For example, Japanese Patent Laid-Open No. 62-
Japanese Laid-Open Patent Publication No. 2-296991 discloses a technique in which the pixel pitch of a projected image is twice or less as compared with the pitch of the lenticular lens 5.
Techniques with 5x or 2.5x are shown.

[0005]

However, it has been found that moire may occur depending on the conditions of the pixel arrangement and the like in the case of designing with the pitch ratio proposed in the above-mentioned prior art.

Further, in recent years, projection type display devices using the above light valves having different projection sizes have been developed. When a projection type display device having a different projection size is constructed using a single light valve, it is Lenticular lens sheets with different types of pitch cannot be used. For example, in manufacturing a 16: 9 wide-screen projection display device using a horizontal light valve having 1000 pixels, the overscan is set to 4% and the projection size is 40 inches or 45 inches.
In order to make the pitch of the image of the pixels of the liquid crystal panel 2.5 times the pitch of the periodic structure of the screen at inches and 50 inches, the pitch of the periodic structure of the screen is 0.37 mm and 0, respectively. 0.42 mm, 0.46 m
It must be m. For this reason, there arises a manufacturing problem that a mold for preparing a screen according to the projection size must be prepared.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a projection type display device in which moire is inconspicuous and good image quality can be obtained.

[0008]

A projection type display device of the present invention which solves the above-mentioned problems includes a screen provided with a lenticular lens having a periodic structure in one direction, a light valve having pixels arranged in a matrix, and The lenticular includes a light source that illuminates a light valve, and a projection lens that receives output light from the light valve and projects an optical image of the light valve onto the screen. The pitch of the image of the pixel in the direction corresponding to the periodic structure on the lens surface is in the range of 2.6 times to 3.6 times or 4.5 times or more, and preferably compared with the pitch of the periodic structure of the screen. The pixel image pitch in the direction corresponding to the periodic structure on the lenticular lens surface is in the range of 2.8 to 3.5 times. And wherein the door. The present invention is particularly effective for a light valve array of delta type.

[0009]

EXAMPLES The present invention will be described in detail below with reference to examples.

FIG. 1 shows an embodiment of the configuration of a rear projection display device using a two-panel rear projection screen. Light valve 2 consisting of liquid crystal panel is irradiation system 1
And the optical image on the liquid crystal panel is projected by the projection lens 3
The image is magnified by and is imaged on the surface of the two-screen 6 composed of the Fresnel lens 4 and the lenticular lens 5. Here, the light valve 2 has pixels in a delta array as shown in FIG.

With respect to the rear projection type display device having the above-mentioned structure and using the lenticular lens of 0.52 mm pitch and the zoomable projection lens, the pitch of the pixels to be projected was changed to observe the moire. The results are shown in Table 1. In the range of the pitch ratio shown in Table 1, moire is observed without displaying the numerical value of the pixel pitch.

[Table 1]

As is clear from Table 1, the pitch of the image of the pixel in the direction corresponding to the periodic structure of the lenticular lens on the surface of the lenticular lens is 2.6 times to 3.6 times that of the lenticular lens. In the period between, no deterioration in image quality due to moire was observed. Similarly, at 4.5 times or more, deterioration of image quality due to moire was not recognized. Further, in the range of 2.8 times to 3.5 times and 4.5 times or more, no moire is observed at all, which is the most preferable range. However, the smaller the pitch of the lenticular lens, the more difficult it is to process, and there is a problem in that it is not preferable in production at a magnification of 4.5 times or more. If the range from 2.6 times to 3.6 times is applied, for example, a horizontal light valve having 1000 pixels is used to obtain 16 times.
When forming a projection display device with a wide screen of 9 pairs, a lenticular with a pitch of about 0.33 mm is used in order to make projection sizes of 40 inches, 45 inches, and 50 inches with an overscan of 4%. One type of lens can be used.

[0013]

As described above, according to the present invention, the ratio between the pitch of the periodic structure of the lenticular lens and the pitch of the image of the pixel in the direction corresponding to the periodic structure of the lenticular lens on the lenticular lens surface is specified. By setting the range, it is possible to reduce the moiré, thereby providing a projection display device with good image quality.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a configuration of a projection display device.

FIG. 2 is a schematic diagram of a light valve having pixels in a light type array.

FIG. 3 is a schematic diagram of a light valve having pixels in a delta arrangement.

[Explanation of symbols]

 1. Irradiation system 2. Light valve 3. Projection lens 4. Fresnel lens 5. Lenticular lens 6. Screen 7. Pixel

Claims (3)

[Claims] 1. A screen provided with a lenticular lens having a periodic structure in one direction, a light valve having pixels arranged in a matrix, a light source for illuminating the light valve, and an output light from the light valve. A projection lens for projecting an optical image of a light valve on the screen, and a pitch of an image of pixels in a direction corresponding to the periodic structure on the lenticular lens surface, as compared with a pitch of the periodic structure of the lenticular lens. Is a range from 2.6 times to 3.6 times, or 4.5 times or more. 2. A screen provided with a lenticular lens having a periodic structure in one direction, a light valve having pixels arranged in a matrix, a light source for illuminating the light valve, and an output light from the light valve. A projection lens for projecting an optical image of a light valve on the screen, and a pitch of an image of pixels in a direction corresponding to the periodic structure on the lenticular lens surface, as compared with a pitch of the periodic structure of the lenticular lens. Is a range of 2.8 times to 3.5 times. 3. The projection display device according to claim 1, wherein the matrix arrangement of the light valves is a delta type.