JP3385291B2 - Projection display device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device which irradiates an optical image formed on a light valve with illumination light and projects it on a screen through a projection lens. 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, this optical image is irradiated with illumination light, and is projected on a screen through a projection lens. 2. Description of the Related Art Projection-type display devices that perform enlargement and projection have been developed. A CRT is 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 a matrix type and a line type and a delta type. FIG. 2 is a schematic view of a pixel 7 arranged in a line type, and FIG. 3 is a schematic view of a pixel 7 arranged in a delta type. Further, as a rear projection screen, a two-panel screen using a combination of a Fresnel lens and a lenticular lens is generally used. FIG. 1 shows the configuration of a rear projection type display device using the above-mentioned two-type rear projection type screen. A light valve 2 composed of a liquid crystal panel is irradiated by an irradiation system 1, and an optical image on the liquid crystal panel is enlarged by a projection lens 3 to form an image on a surface of a double screen 6 composed of a Fresnel lens 4 and a lenticular lens 5. Is done.
The Fresnel lens 4 has a function of directing the incident light in a direction where the observer is located, and the lenticular lens 5 has a function of dispersing the light emitted from the Fresnel lens 4 at an appropriate angle in the horizontal and vertical directions at an appropriate ratio. Have. If 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 arrangement. In the case where the pixels formed in the matrix arrangement and the delta arrangement and the lenticular lens 5 both have a periodic structure in the horizontal direction, the moire occurs in the horizontal direction because the image formed also forms an image in the delta arrangement. I do. Due to this moiré, a technique has been developed to prevent the projected image on the screen from being difficult to see and to make the moiré less noticeable. For example, Japanese Patent Application Laid-Open
JP-A-236282 discloses a technique in which the pixel pitch of a projected image is twice or less than the pitch of the lenticular lens 5.
Techniques of 5 or 2.5 times 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 design using the pitch ratio proposed in the above prior art. Was. Further, in recent years, projection display devices having different projection sizes using the above-described light valves have been developed. In the case where projection display devices having different projection sizes are configured using a single light valve, one type of display device is required. Lenticular lens sheets of different pitches cannot be used. For example, in producing a 16: 9 wide screen projection display device using a light valve having 1000 horizontal pixels, the overscan is set to 4%, the projection size is 40 inches, and the projection size is 45 inches.
In order to make the pitch of the image of the pixel of the liquid crystal panel 2.5 times as large as the pitch of the periodic structure of the screen at inches and 50 inches, the pitch of the periodic structure of the screen should be .42mm, 0.46m
m. For this reason, there is a manufacturing problem that a die for preparing a screen according to the projection size must be prepared. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a projection type display device in which moire is less noticeable and good image quality can be obtained. According to the present invention, there is provided a projection display apparatus comprising: a screen having a lenticular lens having a periodic structure in one direction; and a light valve having pixels arranged in a matrix. A light source that irradiates the 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 .
A matrix of pixels is delta, the Len
Than the pitch of the periodic structure of the Chi Molecular lens, and wherein the pitch of the image of the direction of the pixel corresponding to the periodic structure on the lenticular lens surface is in the range of 3.46 times 2.88 times I do. Hereinafter, the present invention will be described in detail with reference to examples. FIG. 1 shows an embodiment of the configuration of a rear projection display apparatus using a two-panel rear projection screen. The light valve 2 composed of a liquid crystal panel is an irradiation system 1
And the optical image on the liquid crystal panel is projected by the projection lens 3
And an image is formed on the surface of a two-screen screen 6 including the Fresnel lens 4 and the lenticular lens 5. Here, the light valve 2 has delta type pixels as shown in FIG. In the rear projection type display device having the above configuration, using a lenticular lens having a pitch of 0.52 mm, and using a zoomable projection lens, moire was observed by changing the pitch of pixels to be projected. Table 1 shows the results. In the range of the pitch ratio shown in Table 1, moiré was observed without displaying the numerical value of the pixel pitch. [Table 1] As is clear from Table 1, the pitch of the pixel image in the direction corresponding to the periodic structure of the lenticular lens on the lenticular lens surface is 2.6 to 3.6 times the pitch of the lenticular lens. If it is between, the image quality was not degraded due to moiré. Similarly, no deterioration in image quality due to moiré was observed even at 4.5 times or more. Further, in the range of 2.8 to 3.5 times and 4.5 times or more, no moiré is observed at all, which is the most preferable range. However, as the pitch of the lenticular lens becomes smaller, the processing becomes more difficult. When the range of 2.6 times to 3.6 times is applied, for example, a light valve having 1000 horizontal pixels can be used.
In forming a projection display device having a wide screen of 9 pairs, a lenticular having a pitch of about 0.33 mm is required to produce projection screens of 40 inches, 45 inches, and 50 inches with an overscan of 4%. One type of lens can be used. As described above, according to the present invention, the pitch of the periodic structure of the lenticular lens and the pitch of the image of the pixel on the lenticular lens surface in the direction corresponding to the periodic structure of the lenticular lens. By setting the ratio to a specific range, moiré is reduced, whereby a projection display device with good image quality can be provided.

BRIEF DESCRIPTION OF THE 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 line-type arrangement. FIG. 3 is a schematic diagram of a light valve having pixels in a delta arrangement. [Explanation of Codes] Irradiation system 2. Light valve3. Projection lens 4. Fresnel lens5. Lenticular lens 6. Screen 7. Pixel

Claims (1)

(57) 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 irradiating the light valve, and a projection lens that projects on the screen an optical image of the light valve receives the output light from the light bulb, between the pixel in the previous period light valve
The trix-like arrangement is a delta type, and the pitch of the image of the pixel in the direction corresponding to the periodic structure on the lenticular lens surface is 2.88 to 3.46 times the pitch of the periodic structure of the lenticular lens. A projection display device characterized in that the range is twice as large .