White light enhanced color field sequential projection

• US 5,233,385 A
• Filed: 12/18/1991
• Issued: 08/03/1993
• Est. Priority Date: 12/18/1991
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Sampsell, Jeffrey B.
• Primary Examiner(s): Gellner, Michael L.
• Assistant Examiner(s): RUTLEDGE, DELLA J
• Application Number:
  US07/809,816
• Time in Patent Office: 594 Days
• Field of Search: 355/32, 355/35, 355/38, 355/68, 355/77, 355/326, 355/71, 353/84, 356/444, 358/215, 358/216, 358/233, 358/335, 358/345, 359/889, 359/891, 359/315-320, 359/322-325, 359/887
• US Class Current: 355/35
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: H04N 9/3114 by using a sequential colour filter producing one colour at a time

Abstract

A method for increasing the brightness of a scene in a color projection system is disclosed. The brightness can be increased in both temporal and spatial filtering systems. In a temporal system, a portion of the total illumination time is allocated to white light to raise the overall brightness. In a spatial system, part of the illuminated area is allocated to white light. The parts could be allocated as regions on a spatial light modulator, or a spatial light modulator could be dedicated to that area to use white light.

Claims

1. A method for spatial color filtered projection to increase brightness comprising:

a. dividing an area to be illuminated by white light into four regions;

b. allocating said four regions such that each region is dedicated to light with the wavelength of one of three primary additive colors, as well as white light;

c. illuminating said regions;

d. directing said light formed in an image onto a projection surface, such that said light from each of said regions is of the wavelength of its dedicated color when it impinges upon said surface; and

e. selectively blending said light directed from said region allocated to white light with light directed from others of said regions to raise the overall brightness of said image on said surface.

2. The method of claim 1 wherein said area is a color wheel.

3. The method of claim 1 wherein said projection surface is a viewing screen

4. The method of claim 1 wherein said projection surface is a photosensitive media.

5. A method for temporal color filtered projection to increase brightness comprising:

a. dividing a period of time for which a video frame is to be displayed into four segments;

b. illuminating a spatial light modulator for said period;

c. dedicating one filter for each of three primary additive colors as well as white light to one of said four segments; and

d. directing light upon a projection surface from said spatial light modulator wherein said projection surface only receives light of one wavelength during any one of said four segments.

6. The method of claim 5 wherein said four segments reside upon a color wheel.

7. The method of claim 5 wherein said projection surface is a viewing screen.

8. The method of claim 5 wherein said projection surface is a photosensitive media.

9. The method of claim 5 wherein said spatial light modulator is a deformable mirror device.