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

• US 6,359,723 B1
• Filed: 12/13/2000
• Issued: 03/19/2002
• Est. Priority Date: 12/22/1994
• Status: Expired due to Fees

• Current Assignee: Citizen Finetech Miyota Company Limited (Citizen Electronics Company Limited)
• Original Assignee: DT FLCO, Inc. (Micron Technology, Inc.)
• Inventors: Chase, Holden, Handschy, Mark A., Meadows, Michael R.
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): THOMPSON, TIMOTHY J
• Application Number:
  US09/735,109
• Time in Patent Office: 461 Days
• Field of Search: 359/290, 359/629, 359/630, 359/277, 359/631, 359/632
• 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 for producing modulated light which may be viewed by a viewer, the display system comprising:

(a) 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;

(b) a writing arrangement that switches the modulating medium between the different states in a controlled way;

(c) a light source; and

(d) an optics arrangement that directs light from the light source into the spatial light modulator and directs light from the spatial light modulator through a predetermined source imaging area, wherein the optics arrangement cooperates with the light source and the spatial light modulator to produce a real image of the light source within the source imaging area such that a virtual image of substantially only the overall patterns of modulated light produced by the spatial light modulator is directly visible by the viewer from the source imaging area.

2. A system according to claim 1 wherein substantially all of the light directed from the spatial light modulator is directed through the source imaging area except for any light which is specifically absorbed or directed away from the source imaging area by other elements positioned within the optical path between the spatial light modulator and the source imaging area.

3. A system according to claim 1 wherein the spatial light modulator is a reflective type spatial light modulator and wherein the optics arrangement cooperates with the light source and the spatial light modulator such that some of the light passing from the light source to the spatial light modulator overlaps with some of the light passing from the spatial light modulator to the source imaging area.

4. A system according to claim 1 wherein the spatial light modulator is a reflective type spatial light modulator including a light reflecting surface and wherein the optics arrangement includes an eyepiece lens positioned between the spatial light modulator and the source imaging area for establishing the source imaging area.

5. A system according to claim 1 wherein the spatial light modulator is a reflective type spatial light modulator, wherein the light source includes a plurality of sources of light positioned a first distance from one another, and wherein the optics arrangement, cooperating with the light source and the spatial light modulator, produces real images of the plurality of sources of light within the source imaging area such that the real images are spaced apart a second distance from one another which is proportional to the first distance.

6. A system according to claim 1 wherein the spatial light modulator is a reflective type spatial light modulator, wherein the light source forms at least one source of light having a certain spatial extent, and wherein the optics arrangement, cooperating with the light source and the spatial light modulator, produces a real image of the source of light which substantially fills the source imaging area.

7. A system according to claim 6 wherein the optics arrangement includes a combination polarizer-beam splitter-analyzer optically disposed between both the light source and the spatial light modulator and between the spatial light modulator and the source imaging area so as to direct light from the source to the spatial light modulator and from the spatial light modulator to the source imaging area.

8. A system according to claim 7 wherein the optics arrangement further includes a polarizer positioned optically between the light source and the spatial light modulator and an analyzer positioned optically between the spatial light modulator and the source imaging area.

9. A system according to claim 6 wherein the spatial light modulator includes a planar light receiving surface, wherein the optics arrangement directs light from the light source into the spatial light modulator at an acute angle to an axis normal to and centrally located with respect to the light receiving planar surface and from the spatial light modulator in a way which provides the image of the source at the source imaging area, wherein the light source has a corresponding polarizer positioned adjacent to the light source between the light source and the spatial light modulator, and wherein the optics arrangement includes an analyzer positioned between the spatial light modulator and the source imaging area.

10. A system according to claim 6 wherein the optics arrangement directs light from the light source into and from the spatial light modulator in a way which provides an image at a source imaging area and wherein the optics arrangement includes (i) an eyepiece lens positioned between the spatial light modulator and the source imaging area (ii) at least one corresponding polarizer positioned adjacent to the light source between the light source and the spatial light modulator, the light source and corresponding polarizer being positioned between the spatial light modulator and the eyepiece lens, and (iii) an analyzer positioned between the light source and the source imaging area.

11. A display system for producing modulated light which may be viewed by a viewer, the display system comprising:

(a) a reflective type 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;

(b) a writing arrangement that switches the modulating medium between the different states in a controlled way;

(c) a light source; and

(d) an optics arrangement that directs substantially all of the light from the light source into the spatial light modulator and directs substantially all of the light from the spatial light modulator through a predetermined source imaging area except for any light which is specifically absorbed or directed away from the source imaging area by other optical elements positioned within the optical path between the spatial light modulator and the source imaging area, the source imaging area being at least approximately 3 mm in diameter and at most approximately 20 mm in diameter, wherein the optics arrangement cooperates with the light source and the spatial light modulator to produce a real image of the light source within the source imaging area such that (i) a virtual image of substantially only the overall patterns of modulated light produced by the spatial light modulator is directly visible by the viewer from the source imaging area and (ii) any non-illuminated sub-area that might be present within the source imaging area has a maximum extent of at most approximately 3 mm, whereby the viewer that is viewing the virtual image of the overall patterns can do so continuously even if the viewer'"'"'s pupil moves anywhere within the source imaging area including any non-illuminated sub-area.

12. A display system for producing modulated light which may be viewed by a viewer, the display system comprising:

(a) 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;

(b) a writing arrangement that switches the modulating medium between the different states in a controlled way;

(c) a light source; and

(d) an optics arrangement that directs light from the light source into the spatial light modulator and directs light from the spatial light modulator through a predetermined source imaging area, the optics arrangement including a curved surface beam splitter for directing at least a portion of the light from the light source into the spatial light modulator, wherein the optics arrangement cooperates with the light source and the spatial light modulator to produce a real image of the light source within the source imaging area such that a virtual image of substantially only the overall patterns of modulated light produced by the spatial light modulator is directly visible by the viewer from the source imaging area.

13. A system according to claim 12, wherein the spatial light modulator is a reflective type spatial light modulator and wherein the optics arrangement cooperates with the light source and the spatial light modulator such that some of the light directed from the light source to the spatial light modulator overlaps with some of the light passing from the spatial light modulator to the source imaging area.

14. A system according to claim 12, wherein the spatial light modulator is a reflective type spatial light modulator, wherein the light source forms at least one source of light having a certain spatial extent, and wherein the optics arrangement, cooperating with the light source and the spatial light modulator, produces a real image of the source of light which substantially fills the source imaging area.

15. A system according to claim 13, wherein the curved surface beam splitter is optically disposed between both the light source and the spatial light modulator and between the spatial light modulator and the source imaging area to direct light from the light source to the spatial light modulator and from the spatial light modulator to the source imaging area.

16. A system according to claim 14, wherein the optics arrangement further includes a polarizer positioned optically between the light source and the spatial light modulator and an analyzer positioned optically between the spatial light modulator and the source imaging area.

17. A system according to claim 14, wherein the curved surface beam splitter is a curved surface polarizing beam splitter.

18. A system according to claim 16, wherein the optics arrangement further includes an auxiliary polarizer optically disposed between the light source and the curved surface polarizing beam splitter.

19. A system according to claim 17, wherein the optics arrangement further includes an auxiliary analyzer optically disposed between the curved surface polarizing beam splitter and the source imaging area.

20. A display system for producing modulated light which may be viewed by a viewer, the display system comprising:

(a) 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;

(b) a writing arrangement that switches the modulating medium between the different states in a controlled way;

(c) a light source; and

(d) an optics arrangement that directs light from the light source into the spatial light modulator and directs light from the spatial light modulator through a predetermined source imaging area, the optics arrangement including a curved surface beam splitter for directing at least a portion of the light from the light source into the spatial light modulator.

21. A display system for producing modulated light which may be viewed by a viewer, the display system comprising:

a substantially planar support surface;

a reflective microdisplay panel located on the support surface;

a light source located on the support surface adjacent to the microdisplay panel; and

a beam splitter located above the support surface, the beam splitter being receptive of light from the light source and positioned to reflect at least a portion of the light toward the microdisplay panel.

22. A display system as defined in claim 21, wherein the beam splitter is a curved beam splitter.

23. A display system as defined in claim 21, wherein the beam splitter is a polarizing beam splitter.

24. A display system as defined in claim 21, wherein the beam splitter is a curved polarizing beam splitter.

25. A display system as defined in claim 21, wherein the beam splitter is also receptive of light reflected from the microdisplay panel, the beam splitter allowing at least a portion of the light reflected from the microdisplay panel to pass therethrough toward an imaging area for viewing by the viewer.