Pulsed two lamp single light valve display system

• US 6,252,636 B1
• Filed: 03/11/1998
• Issued: 06/26/2001
• Est. Priority Date: 03/12/1997
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Bartlett, Terry A.
• Primary Examiner(s): Harvey, David E.
• Application Number:
  US09/038,346
• Time in Patent Office: 1,203 Days
• Field of Search: H04/N.931, 348/742, 348/743, 348/744, 348/759, 348/760, 348/761, 348/762, 348/763, 348/764, 348/765, 353/84, 353/85
• US Class Current: 348/743
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]
• CPC Class Codes: H04N 9/3114 by using a sequential colour filter producing one colour at a time
• CPC Class Codes: H04N 9/3155 for controlling the light source light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406
• CPC Class Codes: H04N 9/3164 using multiple light sources

Abstract

A pulse driven two lamp (40, 50) single light valve (62) imaging display system (10). The first lamp (40) is used to generate red light, and the second lamp (50) is used to generate blue and green light. A beam splitter (46) combines the white light of the two light sources, and directs the light to a color wheel (26). The first red lamp (40) is driven at a peak power being 3X the average power rating of the lamp for ⅓ of a video frame. The second blue-green lamp (50) is pulse driven at a peak power being 150% its average power rating for ⅔ of a video frame. The present invention achieves improved color balance and increased intensity, and is a simple and cost effective architecture.

Claims

1. An illumination system, comprising:

a light valve modulating a light beam impinging thereon as a function of a video signal representing a series of video frames;

a first lamp and a second lamp generating a first light source and a second light source, respectively;

optics directing said first light source and said second light source to said light valve to form said light beam;

color means for coloring said first light source a first color and for alternately coloring said second light source a second color and a third color; and

a lamp driver circuit driving said first lamp when said color means colors said first light source said first color, said lamp driver circuit driving said second lamp when said color means alternately colors said second light source both said second color and said third color.

2. The illumination system as specified in claim 1 wherein both said first lamp and said second lamp are pulse driven by said lamp driver circuit at a peak power level being higher than an average power rating of the respective lamp.

3. The illumination system as specified in claim 1 wherein said first color is red, and said second color and said third color is blue and green, respectively.

4. The illumination system as specified in claim 1 wherein said first lamp is driven on for approximately one-third the time for each said video frame, and said second lamp is driven on for approximately two-thirds the time for each said video frame.

5. The illumination system as specified in claim 4 wherein said first lamp is driven on at a peak power level being approximately three times the average power rating of said first lamp.

6. The illumination system as specified in claim 5 wherein said second lamp is driven on at a peak power level being approximately one and one-half the average power rating of said second lamp.

7. The illumination system as specified in claim 1 wherein said first lamp and said second lamp consist of an arc lamp.

8. A method of operating an illumination system as a function of a video signal representing a series of video frames, comprising the steps of:

a) driving a first lamp a first fraction of each said video frame to generate a first light source, and driving a second lamp a second fraction of each said video frame to generate a second light source;

b) coloring said first light source a first color, and alternately coloring said second light source both a second color and a third color;

c) directing said colored first light source and said colored second light source to a light valve; and

d) modulating said colored first light source and said second light source with said light valve to form an image.

9. The method as specified in claim 8 comprising the step of pulse driving both said first light source and said second light source at a peak power being higher than an average power rating of the respective lamp.

10. The method as specified in claim 9 wherein said first lamp is pulse driven for approximately one-third the time of each said video frame, and said second lamp is pulse driven for approximately two-thirds the time for each said video frame.

11. The method as specified in claim 10 wherein said first lamp is pulse driven at a peak power level being approximately three times the average power rating of said first lamp.

12. The method as specified in claim 11 wherein said second lamp is pulse driven at a peak power level being approximately one and one-half times the average power rating of said second lamp.

13. The method as specified in claim 8 wherein said first color, said second color and said third color consist of red, blue and green, respectively.