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Rear projection screen with light diffusion sheet and projector using same
| Details |
Inventors: Yamaguchi, Hiroshi; Ikeda, Kenichi;
Assignee: Matsushita Electric Industrial Co., Ltd. (Osaka, JP)
Primary Examiner: Adams; Russell
Assistant Examiner: Mahoney; Christopher
Attorney, Agent or Firm: Merchant & Gould P.C.
In a screen for a rear image projection system, a Fresnel lens sheet, a lenticular lens array sheet whose longitudinal direction is arranged in the vertical direction, and a light diffusion sheet are provided in that order from the projection side. The light diffusion sheet has louver-shaped light absorption wall columns whose longitudinal direction is arranged in the horizontal direction and a light diffusion layer. The light diffusion layer is located on the observation side of the light absorption wall columns. Projected light is properly dispersed and exits without causing the absorption loss due to the light absorption wall columns. Outside light entering from the observation side is diffused in the light diffusion layer and absorbed by the light absorption wall columns. Also, the total reflection component on the lenticular lens surface is absorbed by the light absorption wall columns. As a result, the decrease of contrast caused by the diffuse reflection can be reduced greatly. Therefore, a rear projection screen and a rear projector that have a great effect of reducing the reflection of the outside light with a small loss of the transmitted light can be obtained. |
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DETAILED DESCRIPTION It is an object of the present invention to provide a rear projection screen that can effectively reduce the reflection of the outside light in the lenticular lens array sheet without greatly decreasing the efficiency for light utilization and have a small decrease in contrast even in a bright environment.
It is another object of the present invention to provide a rear projector that has a high efficiency for light utilization and can display images with an excellent contrast even in a bright environment.
In order to solve the above problems, in the present invention, light absorption wall columns (light blocking wall columns) are formed to transmit the projected light refracted by the lenticular lens, so that the projected light diffuses after passing through the light absorption wall columns.
According to the present invention, the reflection of the outside light can be reduced greatly while minimizing the loss of the projected light.
Therefore, a rear projection screen and a rear projector that are excellent in contrast and have a good efficiency for light utilization can be provided.
A rear projection screen according to a first aspect of the present invention comprises, in the following order from the projection side, a Fresnel lens sheet, a lenticular lens array sheet whose longitudinal direction is arranged in the vertical direction, and a light diffusion sheet.
The light diffusion sheet has louver-shaped light absorption wall columns whose longitudinal direction is arranged in the horizontal direction and a light diffusion layer.
The light diffusion layer is located on the observation side of the light absorption wall columns.
According to the first aspect, the projected light is not affected in the vertical direction by the action of the lenticular lens.
Therefore, the projected light having a sharp directivity is hardly lost by the light absorption wall columns.
On the other hand, the light absorption wall columns effectively absorb the outside light and reduce the reflection of the outside light
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