REAR SURFACE PROJECTION TYPE IMAGE DISPLAY DEVICE

• US 20100328618A1
• Filed: 09/10/2010
• Published: 12/30/2010
• Est. Priority Date: 10/24/2005
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: TANAKA, Kazumasa, HIBI, Hirofumi, MUKAI, Hitoshi, MORISAKI, Hiroyuki, KOKUBO, Tetsushi, TANAKA, Kenji, KONDO, Tetsujiro
• Granted Patent: US 8,337,022 B2
• Time in Patent Office: Days
• US Class Current: 353/38
• CPC Class Codes: G03B 21/62 Translucent screens
• CPC Class Codes: G03B 37/04 with cameras or projectors providing touching or overlapping fields of view
• CPC Class Codes: H04N 9/3167 for polarizing the light beam polarizing optical systems per se G02B27/28

Abstract

A rear projection type image display apparatus having a larger half-power angle and being capable of properly blocking a direct light from a projector for an observer is provided.

The rear projection type image display apparatus includes a projector and a transmission type screen installed at an image formation plane of a projection light and made of a texture. The screen made of the texture is a diffusing material having a large half-power angle except for the direct light, and can prevent a gain from being decreased even at an angle of 60 degrees or larger. Also, a first polarizing plate is arranged in front of an exit pupil of the projector, and a second polarizing plate is arranged near a rear surface of the transmission type screen. Polarization axes of these polarizing plates are configured to be substantially orthogonal to each other, to eliminate the direct light.

Claims

1. A rear projection type image display apparatus characterized by comprising:

one or more projectors for projecting an image having a relatively high luminance; and

a rear projection purpose screen for diffusing an incident light to each of the projectors so that a gain characteristic, in which a gain of an outgoing light for each outgoing angle is normalized by a front gain, does not depend on an incident angle.

2. The rear projection type image display apparatus according to claim 1 characterized by further comprising:

direct light adjusting means for reducing a direct light from the projector, the direct light passing through the rear projection purpose screen.

3. The rear projection type image display apparatus according to claim 1 characterized in that

the direct light adjusting means has a layer for diffusing the incident light.

4. The rear projection type image display apparatus according to claim 2 characterized in that

the rear projection purpose screen is a screen arranged on the projector side and made of a fibrous texture, to diffuse the incident light using a diffraction effect in accordance with a fiber roughness of the fibrous texture, and

the direct light adjusting means is a matt screen arranged on a viewer side.

5. The rear projection type image display apparatus according to claim 1 characterized by further comprising:

direct light blocking means for blocking the direct light from the projector, the direct light passing through the rear projection purpose screen.