High resolution subtractive color projection system

• US 5,594,563 A
• Filed: 05/31/1994
• Issued: 01/14/1997
• Est. Priority Date: 05/31/1994
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Larson, Brent D.
• Primary Examiner(s): Crane, Sara W.
• Assistant Examiner(s): Abraham, Fetsum
• Application Number:
  US08/250,964
• Time in Patent Office: 959 Days
• Field of Search: 359/40, 359/42, 359/53, 359/63, 359/631, 359/634
• US Class Current: 349/74
• CPC Class Codes: G02B 27/1046 for use with transmissive spatial light modulators
• CPC Class Codes: G02B 27/144 using partially transparent surfaces without spectral selectivity G02B27/147 takes precedence
• CPC Class Codes: G02B 27/148 including stacked surfaces having at least one double-pass partially reflecting surface
• CPC Class Codes: G02B 5/26 Reflecting filters G02B5/28 takes precedence
• CPC Class Codes: H04N 9/3126 for spatial light modulators in series

Abstract

A color projector for forming a high resolution image through a plurality of stacked display panels. The projector employs subtractive color technology to project a real or virtual color image. In order to provide a highly focused image free from parallax effects, a dichroic mirror assembly is provided to reflect the light exiting the display panels and compensate for differences in optical path lengths between display panels while maintaining high resolution focusing capability. Light output averaging means are provided to eliminate additional parallax effects. High resolution optics are provided between the dichroic mirror assembly and the projection screen in order to provide focus for the image.

Claims

1. A color projection system comprising:

light producing means;

a plurality of stacked, high resolution display panels with individual picture elements which modulate light produced by said light producing means to form an image;

high resolution compensating means to compensate for parallax artifacts arising from said plurality of stacked high resolution display panels, wherein the high resolution compensating means includes refracting media which retracts the modulated light, the refracting media includes refracting surfaces which receives the modulated light such that all of said refracting surfaces are substantially non-tilted with respect to the plurality of stacked display panels; and

high resolution optical focusing means to focus the modulated light and form a real or virtual composite image.

2. The color projection system of claim 1 wherein said high resolution display panels contain opaque matrix structures.

3. The color projection system of claim 1 wherein said high resolution display panels are active matrix liquid crystal panels.

4. The color projection system of claim 1 wherein there is zero lateral offset between each of the display panels.

5. The color projection system of claim 1 wherein said high resolution compensation means further includes a plurality of stacked dichroic mirrors, each of the mirrors reflects the modulated light in a particular spectral band.

6. The color projection system of claim 5 wherein said plurality of dichroic mirrors are incorporated into a transparent prism.

7. The color projection system of claim 6 wherein the plurality of dichroic mirrors are incorporated in two sides of said prism.

8. The color projection system of claim 7 wherein the prism is triangular to reflect the light from said plurality of display panels approximately 180 degrees.

9. The color projection system of claim 7 wherein there is zero lateral offset between each of said stacked display panels.

10. The color projection system of claim 6 wherein the prism is triangular and the plurality of dichroic mirrors are incorporated in one side of said prism to reflect light from said plurality of display panels approximately 90 degrees.

11. The color projection system of claim 5 wherein absorbing color filter means are interposed between the dichroic mirrors.

12. The color projection system of claim 5 wherein said plurality of dichroic mirrors are substantially parallel to said plurality of display panels and said high resolution optical focusing means has an axis of symmetry which is substantially perpendicular to said plurality of display panels so that only a portion of the modulated light from said plurality of display panels which is not parallel to the axis of focus is collected by said high resolution optical focusing means.

13. The color projection system of claim 5 wherein the separations between the dichroic mirrors are controlled independently of the mirror thickness.

14. The color projection system of claim 5 wherein each of the plurality of dichroic mirrors is partially transmissive in the particular spectral bands and said focusing means includes a curved reflective element.

15. The color projection system of claim 14 wherein the plurality of dichroic mirrors are cholesteric circular polarizing beamsplitters.

16. The color projection system of claim 1 wherein said high resolution of compensating means is comprised of:

a first plurality of dichroic mirrors.

17. The color projection system of claim 16 further comprising beamsplitting means positioned remote from said plurality of stacked high resolution display panels and in the path of the modulated light along the optical path between said plurality of display panels and said first plurality of dichroic mirrors.

18. The color projection system of claim 17 wherein the beamsplitting means reflects a portion of the modulated light 90 degrees to a first plurality of dichroic mirrors which are at a 90 degree angle with respect to the display panels.

19. The color projection system of claim 18 wherein the plurality of dichroic mirrors are curved to provide optical power during reflection of the modulated light.

20. The color projection system of claim 18 wherein the high resolution compensation memos is further comprised of:

a first quarter wave plate positioned between the beamsplitting means and the first plurality of dichroic mirrors;

polarization means for said beamsplitting means;

a second plurality of dichroic mirrors positioned parallel to the plurality of display panels and equal distance from the beamsplitting means and the first plurality of dichroic mirrors; and

a second quarter wave plate positioned between the beamsplitting means and the second plurality of dichroic mirrors.

21. The color projection system of claim 17 wherein a first quarter wave plate is positioned between the beamsplitting means and the first plurality of dichroic mirrors, and wherein the beamsplitting means are polarizing beamsplitting means.

22. The color projection system of claim 17 wherein said beamsplitting means is a pellicle beamsplitter.

23. A color projection system comprising:

light producing means;

a plurality of stacked, high resolution display panels with individual picture elements in the path of said light to modulate the intensity of light produced by said light producing means to form an image; and

a plurality of stacked, curved dichroic mirrors, wherein each of said mirrors selectively reflects and focuses the light modulated by one of the high resolution display panels, to form a real or virtual composite image of said plurality of stacked high resolution display panels.

24. A color projection system comprising:

light producing means;

a plurality of stacked, high resolution display panels with individual picture elements which modulate light produced by said light producing means to form an image;

high resolution compensating means to compensate for parallax artifacts arising from said plurality of stacked high resolution display panels, high resolution compensating means comprising;

a first plurality of dichroic mirrors; and

a second plurality of dichroic mirrors, the second plurality of dichroic mirrors provides compensation for resolution limiting effects introduced by the first plurality of dichroic mirrors; and

high resolution optical focusing means to focus the modulated light and form a real or virtual composite image.

25. A color projection system comprising:

light producing means;

a plurality of stacked, high resolution display panels with individual picture elements which modulate light produced by said light producing means to form an image;

high resolution compensating means to compensate for parallax artifacts arising from said plurality of stacked high resolution display panels, wherein said high resolution compensating means comprises a plurality of very thin stacked dichroic pellicle mirrors and the index of refraction between adjacent dichroic mirrors is the same as the index of refraction in the space separating the plurality of dichroic mirrors from said plurality of display panels; and

high resolution optical focusing means to focus the modulated light and form a real or virtual composite image.

26. The color projection system of claim 25 wherein air is between the adjacent dichroic mirrors.

27. A color projection system comprising:

light producing means;

a plurality of stacked, high resolution display panels with individual picture elements which modulate light produced by said light producing means to form an image;

high resolution compensating means to compensate for parallax artifacts arising from said plurality of stacked high resolution display panels, wherein said high resolution compensation means includes an optical collection angle sufficiently large to average multiple angular interference fringes arising from the passage of uncollimated rays through the plurality of display panels; and

high resolution optical focusing means to focus the modulated light and form a real or virtual composite image; and

wherein a numerical aperture corresponding to the optical collection angle is approximately 2np/D or greater,

wherein is the refractive index of the medium between successive pairs of the plurality of display panels, p is the distance, in millimeters, between adjacent pixels within each of the display panels, and D is the largest separation, in millimeters, between any two of the plurality of display panels.

28. A color projection system comprising:

light producing means;

a plurality of stacked, high resolution display panels with individual picture elements which modulate light produced by said light producing means to form an image;

high resolution compensating means to compensate for parallax artifacts arising from said plurality of stacked high resolution display panels, wherein said high resolution compensation means includes an optical collection angle sufficiently large to average multiple angular interference fringes arising from the passage of uncollimated rays through the plurality of display panels; and

high resolution optical focusing means to focus the modulated light and form a real or virtual composite image; and

wherein;

the optical collection angle is defined by the focal length of the focusing means and the pupil diameter of an observer'"'"'s eye; and

a numerical aperture corresponding to the optical collection angle is approximately 2np/D or greater, where n is the refractive index of the medium between successive pairs of the plurality of display panels, p is the distance, in millimeters, between adjacent pixels within each of the display panels, and D is the largest separation, in millimeters between and two of the plurality of display panels.

29. A color projection system comprising:

light producing means, wherein light produced is substantially uncollimated;

a plurality of stacked, high resolution display panels with individual picture elements which modulate light produced by said light producing means to form an image;

high resolution compensating means to compensate for parallax artifacts arising from said plurality of stacked high resolution display panels, wherein said high resolution compensation means includes an optical collection angle sufficiently large to average multiple angular interference fringes arising from the passage of uncollimated rays through the plurality of display panels; and

high resolution optical focusing means to focus the modulated light and form a real or virtual composite image; and

wherein the optical collection angle is defined by the focal length of the focusing means and the pupil diameter of an observer'"'"'s eye.

30. The color projection system of claim 29 wherein the focusing means provide a virtual image to the observer'"'"'s eye.

31. The color projection system of claim 30 wherein a cone of light rays is identified within the optical collection angle, and said cone of light rays varies as a function of position of the observer'"'"'s eye.

32. A color projection system comprising:

light producing means, wherein light produced is substantially uncollimated;

a plurality of stacked, high resolution display panels with individual picture elements which modulate light produced by said light producing means to form an image;

high resolution compensating means to compensate for parallax artifacts arising from said plurality of stacked high resolution display panels, wherein said high resolution compensation means includes an optical collection angle sufficiently large to average multiple angular interference fringes arising from the passage of uncollimated rays through the plurality of display panels; and

high resolution optical focusing means to focus the modulated light and form a real or virtual composite image; and

wherein at least one of the plurality of display panels is misaligned from the other display panels.