Electro-optic projection display with luminosity channel

• US 6,220,710 B1
• Filed: 05/18/1999
• Issued: 04/24/2001
• Est. Priority Date: 05/18/1999
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Raj, Kannan, Smith, Ronald D.
• Primary Examiner(s): Metjahic, Safet
• Assistant Examiner(s): LEROUX, ETIENNE PIERRE
• Application Number:
  US09/313,814
• Time in Patent Office: 707 Days
• Field of Search: 353/20, 353/31, 353/34, 353/37, 349/5, 349/8, 349/9, 349/25
• US Class Current: 353/20
• CPC Class Codes: G02B 27/145 having sequential partially reflecting surfaces
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• 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

Abstract

A luminosity channel may be provided in an electro-optic projection display by beam splitting the incident light source into first and second polarization beams. One polarization beam may be used to illuminate the three modulators for the three primary color channels. The other beam may be utilized to illuminate a white light modulator which provides a luminosity channel. The two beams may be recombined to produce the final image. As a result, in some embodiments, higher resolution, or wider color gamut, and better image quality may be achieved without unduly effecting the light efficiency of the display.

Claims

1. A method of operating an electro-optic projection display comprising:

generating a light source;

splitting the light from said source into two separately polarized beams including a first beam of a first polarization and a second beam of a second polarization, said first and second polarizations being different polarizations;

forming three color plane channels using said first polarized beam;

forming a luminosity channel using said second polarized beam; and

converting said first and second polarized beams to the same polarization.

2. The method of claim 1 wherein splitting the light source into two separately polarized beams includes splitting the light source equally into two separately polarized beams.

3. The method of claim 1 further including combining said three color plane channels and said luminosity channel and projecting said color plane channels and luminosity channel onto a projection screen.

4. The method of claim 1 wherein forming three color plane channels includes using a set of three spatial light modulators to form said color plane channels and using a separate spatial light modulator to form said luminosity channel.

5. An electro-optic projection display comprising:

a light source;

a variable ratio beam splitter to split the light from said light source into two separately polarized beams in unequal percentages;

a first electro-optic device to form three modulated primary color channels; and

a second electro-optic device to modulate a white light channel. modulators to form said color plane channels and using a separate spatial light modulator to form said luminosity channel.

6. The display of claim 5 further including a half wave plate to convert the polarization of one of said polarized beams to the polarization of the other of said polarized beams.

7. The display of claim 5 wherein said first and second electro-optic devices are spatial light modulators.

8. The display of claim 7 wherein said spatial light modulators use liquid crystal devices.

9. The display of claim 5 wherein said first electro-optic device is adapted to form three modulated primary color channels using three spatial light modulators, one for each primary color channel.

10. The display of claim 5 including a combiner to combine the light produced by said first and second electro-optic devices.

11. An electro-optic projection display comprising:

a spatial light modulator to produce a luminosity channel;

a light source;

a variable ratio beam splitter to split light from said light source into first and second oppositely polarized beams in unequal percentages, one of said oppositely polarized beams to form the light for said luminosity channel; and

a half wave plate to convert the polarization of said first polarized beam to the polarization of the second polarized beam.

12. The display of claim 11 including a spatial light modulator forming a color channel.

13. The display of claim 12 wherein said spatial light modulators use liquid crystal devices.

14. The display of claim 12 including three spatial light modulators adapted to form three modulated primary color channels, one for each primary color channel.

15. The display of claim 14 including a combiner to combine the first and second polarized beams.

16. The display of claim 12, including a high resolution spatial light modulator for said luminosity channel and lower resolution spatial light modulators for said color channels.

17. The display of claim 16 wherein said luminosity channel is adapted to broaden the light responsivity of said display to approximately 400 to 800 nanometers.