Micro-lens array sheet

• US 6,335,828 B1
• Filed: 10/26/1999
• Issued: 01/01/2002
• Est. Priority Date: 10/26/1998
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Hashimoto, Takahiro, Sakamoto, Tsutomu
• Primary Examiner(s): Mahoney, Christopher E.
• Assistant Examiner(s): Cruz, Magda
• Application Number:
  US09/426,860
• Time in Patent Office: 798 Days
• Field of Search: 359/443, 359/451, 359/453, 359/454, 359/457, 359/459, 359/460, 359/628
• US Class Current: 359/443
• CPC Class Codes: G03B 21/625 Lenticular translucent screens

Abstract

A micro-lens array sheet having a wide field angle, a field angle control, a high light efficiency, a high brightness and a high contrast, which is provided with a layer of micro-lenses each shaped to be a centro-symmetry convex or concave micro-lens. A layer of either a light diffusion sheet or a sheet filled with light diffusive agent is attached on a light transmitting side of the micro-lens array sheet. The micro-lenses are aligned in a diamond grid array or an array including a combination of diamond-shape and hexagonal-shape micro-lens blocks.

Claims

1. A micro-lens array sheet having a light incident surface and a light transmitting surface disposed opposite to the light incident surface, the micro-lens array sheet comprising:

a plurality of micro-lenses formed on the light-incident surface, each micro-lens having a centro-symmetry convex or concave shape,

the plurality of micro-lenses being configured to carry a light diffusion element provided on the light transmitting surface of the micro-lens array sheet, the light diffusion element being configured to diffuse light emitted from the plurality of micro-lenses, and

wherein the plurality of micro-lenses are arrayed in a diamond-shape block.

2. A micro-lens array sheet according to claim 1, wherein the light diffusion element is a light diffusion sheet provided on the light transmitting surface of the array.

3. A micro-lens array sheet according to claim 1, wherein the light diffusion element is a light diffusive agent dispersed in the plurality of micro-lenses.

4. A micro-lens array sheet having a light incident surface and a light transmitting surface disposed opposite to the light incident surface, the micro-lens array sheet comprising:

a plurality of micro-lenses formed on the light-incident surface, each micro-lens having a centro-symmetry convex or concave shape,

the plurality of micro-lenses being configured to carry a light diffusion element provided on the light transmitting surface of the micro-lens array sheet, the light diffusion element being configured to diffuse light emitted from the plurality of micro-lenses, and

wherein the plurality of micro-lenses are arrayed in a combination of diamond-shape micro-lens blocks and hexagonal-shape micro-lens blocks.

5. A micro-lens array sheet according to claim 4, wherein the light diffusion element is a light diffusion sheet provided on the light transmitting surface of the array.

6. A micro-lens array sheet according to claim 4, wherein the light diffusion element is a light diffusive agent dispersed in the plurality of micro-lenses.

7. A display screen for use in a rear projection type video display apparatus comprising:

a micro-lens array sheet having a light incident surface and a light transmitting surface disposed opposite to the light incident surface, the micro-lens array sheet comprising

a plurality of micro-lenses formed on the light-incident surface, each micro-lens having a centro-symmetry convex or concave shape, the micro-lens array being configured to carry a light diffusion element provided on the light transmitting surface of the plurality of micro-lenses, the light diffusion element being configured to diffuse light emitted from the plurality of micro-lenses,

wherein the micro-lenses are arrayed in one of a diamond-shape block and a combination of diamond-shape micro-lens blocks and hexagonal-shape micro-lens blocks.

8. A display screen according to claim 7, wherein the plurality of micro-lenses has a horizontal aligning pitch that is different from the vertical aligning pitch thereof.

9. A display screen according to claim 7, wherein the plurality of micro-lenses are configured to have a semi-oval asymmetrical configuration along a horizontal axis thereof so as to provide different vertical field angles between an upward direction and a downward direction.

10. A display screen according to any one of claims 7-8 further comprising a light shielding layer provided on the light transmitting surface of the micro-lens array sheet, the light shielding layer having openings facing the plurality of micro-lenses and being configured to emit light incident to the micro-lenses through the openings.

11. A projection type video display apparatus comprising:

a video generator configured to generate video data; and

a display screen configured to display the video data thereon, the display screen including a micro-lens array sheet having a light incident surface and a light transmitting surface disposed opposite to the light incident surface, the micro-lens array sheet comprising

a plurality of micro-lenses formed on the light-incident surface, each micro-lens having a centro-symmetry convex or concave shape, the plurality of micro-lenses being configured to carry a light diffusion element provided on the light transmitting surface of the array and configured to diffuse light emitted from the plurality of micro-lenses,

wherein the micro-lenses are arrayed in one of a diamond-shape block and a combination of diamond-shape micro-lens blocks and hexagonal-shape micro-lens blocks.