Rear projection apparatus

• US 6,661,552 B2
• Filed: 09/05/2002
• Issued: 12/09/2003
• Est. Priority Date: 10/18/1999
• Status: Expired due to Fees

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Hitachi, Ltd., Nitto Denko Corporation
• Inventors: Hira, Yasuo
• Primary Examiner(s): Schwartz, Jordan M.
• Assistant Examiner(s): THOMPSON, TIMOTHY J
• Application Number:
  US10/234,090
• Publication Number:
  US 20020196516A1
• Time in Patent Office: 460 Days
• Field of Search: 359/237, 359/619, 359/242, 359/618, 359/620, 359/452, 359/456, 359/741
• US Class Current: 359/237
• CPC Class Codes: G03B 21/625 Lenticular translucent screens
• CPC Class Codes: H04N 5/66 Transforming electric information into light information scanning details H04N3/00
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells

Abstract

A rear projection apparatus having a projector containing a light source and a liquid crystal cell, a mirror for reflecting a light from the projector, and a screen for projecting the light reflected by the mirror. The screen is being composed of an optical film having an optical element capable of forming a spatial distribution of light transmittance, a light shield layer and a light diffusion layer. The light shield layer is positioned between the optical element and the light diffusion layer and is composed of a compound which changes light transmittance depending on irradiation of an energy beam. The light transmittance passing the light shield layer is modulated spatially depending on a dose of the energy beam.

Claims

1. A rear projection apparatus comprising a projector containing a light source and a liquid crystal cell, a mirror for reflecting a light from the projector, and a screen for projecting the light reflected by the mirror, the screen being composed of an optical film comprising an optical element capable of forming a spatial distribution of light transmittance, a light shield layer and a light diffusion layer, the light shield layer being positioned between the optical element and the light diffusion layer and being composed of a compound which changes light transmittance depending on irradiation of an energy beam, wherein the light transmittance passing the light shield layer is modulated spatially depending on a dose of the energy beam, and wherein the light shield layer and the light diffusion layer are positioned with a gap of no greater than 400 μ

m.

2. A rear projection apparatus according to claim 1, wherein the optical element is a microlens array, and positioned at a side of the rear projection apparatus where the light from the light source is incident.

3. A rear projection apparatus according to claim 1, wherein the compound composing the light shield layer is at least silver or a compound containing silver.

4. A rear projection apparatus comprising a projector containing a light source and a liquid crystal cell, a mirror for reflecting a light from the projector, and a screen for projecting the light reflected by the mirror, the screen being composed of an optical film comprising an optical element capable of forming a spatial distribution of light transmittance, and a light shield layer positioned on an opposite side of the optical element, the light shield layer containing small balls having transmittivity.

5. A rear projection apparatus according to claim 4, wherein the optical element is a microlens array, and is positioned at a side of the rear projection apparatus where the light from the light source is incident.

6. A rear projection apparatus according to claim 4, wherein the small balls have a diameter of 0.1 to 6 μ

m and are contained in the light shield layer in a proportion of 1 to 30% by weight.

7. A rear projection apparatus according to claim 4, wherein the optical element is a microlens array, and the light transmitting regions are positioned near the regions of focus of the microlens.

8. A rear projection apparatus comprising a projector containing a light source and a liquid crystal cell, a mirror for reflecting a light from the projector, and a screen for projecting the light reflected by the mirror, the screen being composed of an optical film comprising a microlens array, a light shield layer and a light diffusion layer, the light shield layer being positioned between the microlens array and the light diffusion layer, and the light shield layer being composed of a compound which changes light transmittance depending on irradiation of an energy beam and is at least silver or a compound containing silver, wherein the light transmittance passing the light shield layer is modulated spatially depending on a dose of the energy beam, and high light transmittance regions in the light shield layer are obtained on optical axes of the microlens array.