Projection system

• US 6,542,134 B1
• Filed: 03/24/1999
• Issued: 04/01/2003
• Est. Priority Date: 03/24/1999
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Raj, Kannan
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): Osorio, Ricardo
• Application Number:
  US09/275,746
• Time in Patent Office: 1,469 Days
• Field of Search: 345/32, 359/15, 359/629, 359/633, 359/634, 359/639, 353/31, 349/25, 349/57
• US Class Current: 345/32
• CPC Class Codes: G02B 27/1026 for use with reflective spatial light modulators
• CPC Class Codes: G02B 27/1086 operating by diffraction only
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10
• CPC Class Codes: H04N 9/312 Driving therefor driving of electronic spatial light modulators in displays other than projection devices G09G3/34, G09G3/36; control of liquid crystal elements G02F1/133; control of micromechanical modulators G02B26/08

Abstract

A projection system includes at least one light source, at least one light modulator and a holographic beam splitter. The light source(s) are adapted to furnish unmodulated beams of light, and each unmodulated beam of light is associated with a different color channel. Each light modulator is associated with a different one of the unmodulated beams of light and is adapted to modulate the associated unmodulated beam of light to produce a modulated beam of light. The holographic beam splitter is adapted to direct each of the unmodulated beams of light to the associated light modulator.

Claims

1. A projection system comprising:

at least one light source to furnish light comprising multiple color channels;

a first light modulator associated with one of the color channels;

a second light modulator associated with another one of the color channels, the second light modulator being separate from the first light modulator; and

a holographic beam splitter comprising a substantially planar medium including multiple recorded interference patterns to selectively establish a first optical path for said one of the color channels between the beam splitter and the first light modulator in response to a wavelength associated with said one of the color channels and establish a second optical path for said another one of the color channels between the beam splitter and the second light modulator in response to a wavelength associated with said another one of the color channels.

2. The projection system of claim 1, further comprising:

projection optics, and

wherein the holographic beam splitter is further adapted to establish optical communication between the first and second light modulators and the projection optics to produce a composite image.

3. The projection system of claim 1, wherein

said at least one light source is adapted to produce unmodulated beams of light, and

the unmodulated beams of light are associated with at least three of the color channels.

4. The projection system of claim 1, wherein

said at least one light source is adapted to produce unmodulated beams of light, and

the unmodulated beams of light are associated with at least four of the color channels.

5. The projection system of claim 1, wherein each of the different paths is associated with a different one of the color channels.

6. The projection system of claim 1, wherein the paths form different exit angles relative to the beam splitter.

7. A projection system comprising:

at least one light source to furnish unmodulated beams of light, each unmodulated beam of light being associated with a different color channel;

a first light modulator associated with one of the unmodulated beams of light and being adapted to modulate said one of the unmodulated beams of light to produce a first modulated beam of light;

a second light modulator associated with another one of the unmodulated beams of light and being adapted to modulate said another one of the unmodulated beams of light to produce a second modulated beam of light, the second light modulator being separate from the first light modulator; and

a holographic beam splitter comprising a substantially planar medium including multiple recorded interference patterns to selectively establish a first optical path for said one of the unmodulated beams of light between the beam splitter and the first light modulator in response to a wavelength associated with said one of the unmodulated beams of light and establish a second optical path for said another one of the other unmodulated beams of light between the beam splitter and the second light modulator in response to a wavelength associated with said another one of the unmodulated beams of light.

8. The projection system of claim 7, further comprising:

projection optics,

wherein the holographic beam splitter is further adapted to direct the modulated beams of light to the projection optics to form a composite image.

9. The projection system of claim 7, wherein the holographic beam splitter comprises:

a phase-based holographic beam splitter.

10. The projection system of claim 7, wherein the unmodulated beams of light are associated with at least three of the color channels.

11. The projection system of claim 7, wherein the unmodulated beams of light are associated with at least four of the color channels.

12. The projection system of claim 7, wherein said at least one light source comprises:

a light emitting diode.

13. The projection system of claim 7, wherein said at least one light source comprises:

a laser.

14. The projection system of claim 7, wherein at least one of the first and second light modulators comprises:

a liquid crystal display panel.

15. The projection system of claim 7, wherein each of the different paths is associated with a different one of the color channels.

16. The projection system of claim 7, wherein the paths form different exit angles relative to the beam splitter.

17. A method comprising:

furnishing reference waves of light, each reference wave of light being associated with a different color channel;

on a substantially planar recording medium recording interference patterns, each of the interference patterns being associated with a different one of the reference waves of light;

using the interference patterns to produce object waves of light, each of the object waves being associated with one of the color channels;

directing the reference waves to separate light modulators, each of the light modulators being associated with one of the color channels; and

modulating the object waves to produce modulated light waves.

18. The method of claim 17, wherein the act of modulating the object waves comprises:

directing the modulated light waves to optics to form a multicolor image.

19. The method of claim 18, wherein the act of directing comprises:

using the interference patterns.

20. The method of claim 17, wherein the act of furnishing comprises:

using lasers to furnish the reference waves of light.

21. The method of claim 17, wherein the act of furnishing comprising:

using light emitting diodes to furnish the reference waves of light.