Optics arrangements including light source arrangements for an active matrix liquid crystal image generator

• US 7,012,730 B2
• Filed: 02/04/2002
• Issued: 03/14/2006
• Est. Priority Date: 12/22/1994
• Status: Expired due to Fees

• Current Assignee: Citizen Finetech Miyota Company Limited (Citizen Electronics Company Limited)
• Original Assignee: Displaytech Inc (Micron Technology, Inc.)
• Inventors: Handschy, Mark A., Meadows, Michael R., Chase, Holden
• Primary Examiner(s): THOMPSON, TIMOTHY J
• Application Number:
  US10/067,516
• Publication Number:
  US 20030007229A1
• Time in Patent Office: 1,499 Days
• Field of Search: 359/290, 359/619, 359/245, 359/248, 359/291, 349/58, 349/61, 349/68, 362/227, 362/230, 362/231, 362/246, 362/800, 345/7, 345/8, 353/98, 353/37, 353/30, 353/99
• US Class Current: 359/290
• CPC Class Codes: G02B 27/1033 having a single light modulator for all colour channels
• CPC Class Codes: G02B 27/1053 having a single light modulator for all colour channels
• CPC Class Codes: G02B 27/1086 operating by diffraction only
• CPC Class Codes: G02B 27/123 The splitting element being a lens or a system of lenses, including arrays and surfaces with refractive power
• 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: G02B 6/0033 Means for improving the coupling-out of light from the light guide
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02F 1/133526 Lenses, e.g. microlenses or Fresnel lenses
• CPC Class Codes: G02F 1/1336 Illuminating devices
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133609 including means for improving the color mixing, e.g. white
• CPC Class Codes: G02F 1/133616 Front illuminating devices
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one
• CPC Class Codes: G02F 1/133622 Colour sequential illumination
• CPC Class Codes: G02F 1/136277 formed on a semiconductor substrate, e.g. of silicon
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A system for producing modulated light is disclosed. The system comprises a spatial light modulator including a light modulating medium switchable between different states so as to act on light in ways which form overall patterns of modulated light. The system also includes an arrangement for switching the modulating medium between the different states in a controlled way and an illumination arrangement for producing a source of light. The system further includes an optics arrangement for directing light from the source of light into the spatial light modulator and for directing light from the spatial light modulator through a predetermined source imaging area. The optics arrangement cooperates with the illumination arrangement and the spatial light modulator so as to produce a real image of the source of light within the source imaging area such that an individual is able to view a virtual image of the overall patterns of modulated light from the source imaging area. A variety of novel optics arrangements are disclosed including specific combinations of different light sources, diffusing plates, polarizers, beam splitters, analyzers, lenses, mirrors, and holographic optical elements which allow the overall optical arrangement to be miniaturized to the same degree and in coordination with the spatial light modulator. The different light sources include using a plurality of light sources, such as LEDs, to form an array of light sources, each of the light sources providing light to a corresponding portion of the spatial light modulator.

Claims

1. A display system, comprising:

a support surface;

a source of light located proximate to the support surface;

a microdisplay located proximate to the support surface; and

a reflector located above the support surface and spaced apart from the support surface in position to reflect the light from the source of light to eventually illuminate the microdisplay;

wherein the source of light includes three LEDs, wherein each LED produces light of a different color.

3. A display system as defined in claim 1, wherein the reflector is curved.

7. A display system as defined in claim 1, wherein the microdisplay is a reflective microdisplay.

8. A display system as defined in claim 1, further including optical elements positioned in a light path above the microdisplay, wherein the microdisplay is a reflective microdisplay, wherein the optical elements are receptive of light reflected from the microdisplay, the optical elements directing the reflected light for viewing, and further wherein the reflector is positioned in the light path between the microdisplay and the optical elements.

9. A display system as defined in claim 1, wherein each of the light source and the microdisplay have a primary optical axis, and further wherein these optical axes intersect with one another.

10. A display system as defined in claim 1, wherein the microdisplay is a reflective liquid crystal spatial light modulator.

11. A display system as defined in claim 10, wherein the spatial light modulator is pixellated.

12. A display system as defined in claim 10, wherein the spatial light modulator uses ferroelectric liquid crystals.

2. A display system, comprising:

a support surface;

a source of light located proximate to the support surface;

a microdisplay located proximate to the support surface; and

a reflector located above the support surface and spaced apart from the support surface in position to reflect the light from the source of light to eventually illuminate the microdisplay;

wherein the source of light includes one or more LEDs;

wherein the reflector is substantially planar.

4. A display system, comprising:

a support surface;

a source of light located proximate to the support surface;

a microdisplay located proximate to the support surface; and

a reflector located above the support surface and spaced apart from the support surface in position to reflect the light from the source of light to eventually illuminate the microdisplay;

wherein the source of light includes one or more LEDs;

wherein the reflector is a beam splitter.

13. A display system as defined in claim 4, wherein the beam splitter is optically disposed between both the light source and the spatial light modulator and between the spatial light modulator and a source imaging area, the beam splitter directing light from the light source to the spatial light modulator and from the spatial light modulator to the source imaging area.

5. A display system, comprising:

a support surface;

a source of light located proximate to the support surface;

a microdisplay located proximate to the support surface; and

a reflector located above the support surface and spaced apart from the support surface in position to reflect the light from the source of light to eventually illuminate the microdisplay, wherein the beam splitter is a polarizing beam splitter.

6. A display system, comprising:

a support surface;

a source of light located proximate to the support surface;

a microdisplay located proximate to the support surface; and

a reflector located above the support surface in position to reflect the light from the source of light to eventually illuminate the microdisplay;

wherein the display system generates a color image via the single microdisplay.

14. A display system, comprising:

a microdisplay that lies substantially in a plane;

a source of light located proximate to the plane, the source being oriented to direct light up and away from the plane; and

an optical element located above the plane in position to direct the light from the source of light toward the microdisplay, the optical element being substantially further away from the microdisplay than is the source of light, wherein the optical element includes a reflector, wherein the reflector is a beam splitter;

wherein the display system generates a color image via the single microdisplay.

22. A display system as defined in claim 14, wherein the beam splitter is optically disposed between both the light source and the spatial light modulator and between the spatial light modulator and a source imaging area, the beam splitter directing light from the light source to the spatial light modulator and from the spatial light modulator to the source imaging area.

15. A display system, comprising:

a microdisplay that lies substantially in a plane;

a source of light located proximate to the plane, the source being oriented to direct light up and away from the plane; and

an optical element located above the plane in position to direct the light from the source of light toward the microdisplay, the optical element being substantially further away from the microdisplay than is the source of light, wherein the optical element includes a reflector, wherein the reflector is a polarizing beam splitter.

16. A display system, comprising:

a microdisplay that lies substantially in a plane;

a source of light located proximate to the plane, the source being oriented to direct light up and away from the plane; and

an optical element located above the plane in position to direct the light from the source of light toward the microdisplay, the optical element being substantially further away from the microdisplay than is the source of light, wherein the optical element includes a reflector, wherein the reflector is a holographic beam splitter.

17. A display system, comprising:

a microdisplay that lies substantially in a plane;

a source of light located proximate to the plane, the source being oriented to direct light up and away from the plane; and

an optical element located above the plane in position to direct the light from the source of light toward the microdisplay, the optical element being substantially further away from the microdisplay than is the source of light;

wherein each of the light source and the microdisplay have a primary optical axis, and further wherein these optical axes intersect with one another;

wherein the display system generates a color image via the single microdisplay.

18. A display system, comprising:

a microdisplay that lies substantially in a plane;

a source of light located proximate to the plane, the source being oriented to direct light up and away from the plane; and

an optical element located above the plane in position to direct the light from the source of light toward the microdisplay, the optical element being substantially further away from the microdisplay than is the source of light;

wherein the display system generates a color image via the single microdisplay.

19. A display system as defined in claim 18, wherein the microdisplay is a reflective liquid crystal spatial light modulator.

20. A display system as defined in claim 19, wherein the spatial light modulator is pixellated.

21. A display system as defined in claim 19, wherein the spatial light modulator uses ferroelectric liquid crystals.

26. A display system as defined in claim 18, wherein the optical element includes a reflector.

27. A display system as defined in claim 26, wherein the reflector is curved.

28. A display system as defined in claim 18, wherein the microdisplay is a reflective microdisplay.

23. A display system, comprising:

a microdisplay that generates an image thereon having a lateral extent;

a source of light located within a distance of the microdisplay, the distance being less than the lateral extent of the generated image on the microdisplay; and

a reflector spaced apart from the microdisplay in position to reflect the light from the source of light to eventually illuminate the microdisplay.

29. A display system as defined in claim 23, further including optical elements positioned in a light path above the microdisplay, wherein the microdisplay is a reflective microdisplay, wherein the optical elements are receptive of light reflected from the microdisplay, the optical elements directing the reflected light for viewing, and further wherein the reflector is positioned in the light path between the microdisplay and the optical elements.

24. A display system, comprising:

a microdisplay;

a source of light located proximate to the microdisplay; and

a reflector spaced apart from the microdisplay in position to reflect the light from the source of light to eventually illuminate the microdisplay;

wherein the source of light is closer to the microdisplay than to the reflector;

wherein the display system generates a color image via the single microdisplay.

25. A display system, comprising:

a reflective microdisplay that generates an image thereon having a lateral extent; and

a source of light located within a distance of the microdisplay, the distance being less than the lateral extent of the generated image on the microdisplay;

wherein light from the source of light is eventually directed toward the microdisplay.