JPH0572634A - Rear projection type screen - Google Patents

Abstract

PURPOSE:To obtain a high-contrast rear projection type display device by absorbing external light such as an indoor illumination light. CONSTITUTION:In this rear projection type screen for oblique projection obtained by forming a fine prism group 2 on a side on which projected light 1 is made incident, a light non-incident part on the side on which the projected light 1 is made incident is set as a light absorbing surface 15 and a light emitting surface 3 on an observation side is set as a lenticular lens group. And a light non-emitting part 4 is set as a light absorbing surface 5 for absorbing the external light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen used for a display device for magnifying and projecting a video image or a computer image from the rear.

[0002]

2. Description of the Related Art Conventionally, there is known a magnifying projection display device which magnifies and projects a display image of a CRT or a liquid crystal on a screen.

Recently, an oblique rear projection type display device, which aims to make the depth of the rear projection type display device very thin, enlarges a display image of a CRT or a liquid crystal or the like diagonally on the screen to show a large screen. Is proposed. The screen used for this is, as seen in JP-A-61-28041, the projection light emitted from the projection lens is made incident from the oblique rear direction of the screen and is totally reflected by a minute prism provided on the entire surface of the screen. And is emitted to the observer side.

[0004]

In the projection optical display device using the screen, as shown in FIG. 5, external light such as illumination light illuminating the room where the observer is present is reflected on the front surface of the screen. Or, it may enter from the front of the screen, enter the cabinet, be reflected by the reflection mirror provided in the cabinet, and then return to the screen again, causing a problem that the contrast of the enlarged projection image is significantly reduced. It was

It is an object of the present invention to provide a high-contrast rear projection screen which reflects little external light such as illumination light.

[0006]

[Means for Solving the Problems] The light non-incident part on the projection light incident side of the screen is used as a light absorbing surface, and the light non-emitter part on the observation side of the screen absorbs external light such as room illumination light. To provide a light absorption band. Furthermore, in order to absorb the light that enters the screen from an oblique direction, a groove is provided in the light non-emission part,
The groove is filled with a light absorbing material.

[0007]

【Example】

(Embodiment 1) FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows an embodiment of a rear projection type display device using a rear projection screen according to the present invention.

As shown in FIG. 2, the projection light 1 emitted from the projection optical unit 8 including the display body is reflected by the first reflection mirror 9.
After being reflected by the second reflection mirror 10 and reflected by the second reflection mirror 10, the light is incident on the screen 7 from an oblique direction. As shown in FIG. 1, the projection light 1 that is obliquely incident on the screen 7 is totally reflected by the prism group 2 and then emitted from the front surface of the screen 7 to the observer side. Therefore, the observer can observe a bright display image that is an enlarged projection image of the display body even in a bright room under the indoor illumination light 6.

FIG. 3 is a horizontal sectional view of the screen 7.
As shown in FIG. 3, since the light emitting unit 3 on the front surface of the screen 7 is provided with the lenticular lens group 12 for diffusing the projection light 1 in the horizontal direction of the screen, the observer moves in the horizontal direction. Even in this case, a bright magnified projection image can be observed as in the case of observing in front of the screen 7.

As shown in FIG. 1, there are a light emitting portion 3 and a light non-emitting portion 4 on the observation side surface of the screen. By setting the light non-emission part 4 as the light absorbing surface 5, a part of the illumination light 6 illuminating the room where the observer is present is absorbed by the light absorbing surface 5.

Among the illumination light 6, there is also a reflected light 14 that enters the inside of the screen 7 without passing through the light absorption surface 5, enters the inside of the cabinet 11, is reflected by the reflection mirror 10, and returns to the screen again. Are absorbed by the light absorbing surface 15 of the prism portion. Even if the light is not absorbed by the light absorbing surface, the light absorbed by the light absorbing surface 5 on the observation side and finally returned to the observer becomes very small.

(Embodiment 2) FIG. 4 shows another embodiment of the present invention.

Similar to the first embodiment, the light non-emission part 4 on the front surface of the screen is used as the light absorbing surface 5, and the groove 13 is provided in the light absorbing surface 5, and the groove is filled with the light absorbing substance. Then,
External light 6 from an oblique direction, which is not absorbed in Example 1, is also absorbed by the groove 13 and the amount of light returning to the observer is smaller than that in Example 1.

[0014]

As described above, external light such as illumination light is less likely to be reflected on the surface of the screen, and is less likely to enter and return inside the rear projection display device. Can provide a high-contrast rear projection screen.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a screen according to the present invention.

FIG. 2 is a vertical cross-sectional view of a rear projection type display device using the screen of the present invention.

FIG. 3 is a horizontal sectional view of a lenticular portion of the screen of the present invention.

FIG. 4 is a vertical sectional view of a screen according to a second embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of a conventional screen.

[Explanation of symbols]

 1 Projection Light 2 Prism Group 3 Light Emitting Portion 4 Light Non-Emitting Portion 5 Light Absorbing Surface 6 Illumination Light 7 Screen 8 Projection Optical Unit 9 First Reflecting Mirror 10 Second Reflecting Mirror 11 Cabinet 12 Lenticular Lens Group 13 Groove 14 Reflection Light 15 Light absorbing surface

Claims (2)

[Claims] 1. A large number of minute prism groups extending linearly or arcuately are formed on a light incident side of a screen surface, and the incident light is totally reflected by each prism constituting the prism group. And a total reflection surface is formed so as to be emitted to the observation side, and a light absorption band is provided in the non-incidence portion on the projection light incident side of the screen, and the light emission on the observation side of the screen is performed. The rear projection screen is characterized in that a lenticular lens for diffusing light in the horizontal direction is formed in the portion, and a light absorption band is formed in the light non-emission portion on the observation side. 2. The rear projection screen according to claim 1, wherein a groove is provided in the light non-emission portion on the observation side of the screen, and the groove portion is filled with a light absorbing substance.