Peak brightness improvement for LC/DLP based RPTV

• US 20030214637A1
• Filed: 05/17/2002
• Published: 11/20/2003
• Est. Priority Date: 05/17/2002
• Status: Active Grant

• Current Assignee: Thomson Licensing SA (Vantiva SA)
• Original Assignee: Thomson Licensing SA (Vantiva SA)
• Inventors: Drazic, Valter, OʼDonnell, Eugene Murphy
• Granted Patent: US 6,837,584 B2
• Time in Patent Office: Days
• US Class Current: 353/74
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor
• CPC Class Codes: H04N 9/3141 Constructional details thereof details not peculiar to the presence of an electronic spatial light modulator G03B21/14
• CPC Class Codes: H04N 9/315 Modulator illumination systems general applications of lighting devices F21V; general optical systems G02B; lamp houses for projectors not peculiar to the presence of an electronic spatial light modulator G03B21/20

Abstract

A method and apparatus for producing an apparent increase in display brightness in an RPTV engine without an actual increase in total light output. Light is generated with an illumination source and optically processed to produce a light beam of rectangular format. The light beam is formed intentionally to have an intensity that is non-uniform, varying from a peak intensity at a center of the beam to a minimum intensity at a periphery of the beam. The optical processing step can include varying the intensity to selectively produce an illumination profile that decreases by at least about 30% to 70% from the peak intensity to the minimum intensity. The optical processing step can further include projecting the light beam through an integrator that is configured to produce an illumination profile that is at least partially controlled by a length of the integrator. The integrator can be configured so that a decrease in length will result in reduced uniformity.

Claims

1. In an RPTV engine, a method for producing an increase in display brightness without an actual increase in total light output, comprising:

generating light using an illumination source;

optically processing said light generated by said illumination source to produce a light beam of rectangular format with an intensity that is non-uniform, varying from a peak intensity at a center of the beam to a minimum intensity at a periphery of said beam; and

projecting said light on at least one imager of an RPTV engine.

2. The method according to claim 2 wherein said optical processing step further comprises varying said intensity to selectively produce an illumination profile which decreases by at least about 30% to 70% from said peak intensity to said minimum intensity.

3. The method according to claim 2 wherein said optical processing step further comprises projecting said light beam through an integrator, and wherein said illumination profile is at least partially controlled by a length of said integrator.

4. The method according to claim 3 wherein said integrator is selectively decreased in length for reduced uniformity.

5. An RPTV engine for providing an apparent increase in display brightness without an actual increase in total light output, comprising:

an illumination source for generating light;

an optical processor, said optical processor converting said light generated by said illumination source to a light beam of rectangular format with an intensity that is non-uniform and varying from a peak intensity at a center of the beam to a minimum intensity at a periphery of said beam and

at least one imager of an RPTV engine upon which said light beam is projected.

6. The apparatus according to claim 5 wherein said optical processor comprises a light integrator, said light integrator varying said intensity to selectively produce an illumination profile which decreases by at least about 30% to 70% from said peak intensity to said minimum intensity.

7. The apparatus according to claim 6 wherein said light integrator is an integrator, and said optical processor further comprises a lens for projecting said light beam through said integrator.

8. The apparatus according to claim 7 wherein said illumination profile is selectively determined based at least in part on a length of said integrator.

9. The apparatus according to claim 8 wherein said integrator is selectively decreased in length for reduced uniformity.