Image projector

• US 5,267,029 A
• Filed: 01/31/1992
• Issued: 11/30/1993
• Est. Priority Date: 12/28/1989
• Status: Expired due to Term

• Current Assignee: Katsumi Kurematsu, Nobuo Minoura, Oshima, Shigeru
• Original Assignee: Katsumi Kurematsu, Nobuo Minoura, Oshima, Shigeru
• Inventors: Oshima, Shigeru, Kurematsu, Katsumi, Minoura, Nobuo
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): Lee, Michael H.
• Application Number:
  US07/830,490
• Time in Patent Office: 669 Days
• Field of Search: 358/60-64, 358/59, 358/230-234, 353/30, 353/31, 353/33, 353/32, 353/34, 353/37, 359/41
• US Class Current: 348/751
• 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
• CPC Class Codes: H04N 9/3167 for polarizing the light beam polarizing optical systems per se G02B27/28

Abstract

An image projector has a device for supplying a first light exhibiting a first color and a second light exhibiting a second color differing from the first color, a first generator for modulating the first light and generating a first image by polarized lights whose planes of polarization are orthogonal to each other, a second generator for modulating the second light and generating a second image by polarized lights whose planes of polarization are orthogonal to each other, an optical coupler for reflecting one of the polarized lights from the first generator and transmitting the other therethrough and transmitting therethrough one of the polarized lights from the second generator and reflecting the other, and a projection optical system for receiving the one polarized light from the first generator and the one polarized light from the second generator through the coupler, and projecting the first and second images by these polarized lights.

Claims

1. An image projector having:

means for supplying first, second and third lights differing in color from one another and polarized in predetermined directions, respectively;

a first liquid crystal light modulator for rotating the plane of polarization of said first light in accordance with an input signal to thereby generate a first image by a first polarized light;

a second liquid crystal light modulator for rotating the plane of polarization of said second light in accordance with an input signal to thereby generate a second image by a second polarized light;

a third liquid crystal light modulator for rotating the plane of polarization of said third light in accordance with an input signal to thereby generate a third image by a third polarized light;

means for projecting said first, second and third images, said projecting means including;

a first polarizing beam splitter disposed at a location whereat said first and second polarized lights from said first and second liquid crystal light modulators intersect each other for reflecting said first polarized light from said first liquid crystal light modulator and transmitting therethrough said second polarized light, from said second liquid crystal light modulator, whereby each of said first and second polarized lights from said first and second liquid crystal light modulators is taken out and synthesized with each other; and

a second polarizing beam splitter for taking out said third polarized light from said third liquid crystal light modulator;

wherein said first, second and third images are projected by said first, second and third polarized lights from said first and second polarizing beam splitters.

2. A projector according to claim 1, wherein said projection means has a first projection lens system for projecting said first image and said second image by said first and second polarized lights from said first polarizing beam splitter, and a second projection lens system for projecting said third image by said third polarized light from said second polarizing beam splitter.

3. A projector according to claim 1, wherein said projection means has a single projection lens system, and said first, second and third images are projected by said projection lens system.

4. A projector according to claim 3, wherein said second polarizing beam splitter has predetermined wavelength dependency and is disposed in the optical path of said first and second polarized lights from said first polarizing beam splitter, and said second polarizing beam splitter transmits each of said first and second polarized lights therethrough and reflects said third polarized light from said third liquid crystal light modulator and directs it to said projection lens system.

5. A projector according to claim 3, wherein said projection means has a dichroic mirror for reflecting one of said first and second polarized lights from said first polarizing beam splitter and said third polarized light from said second polarizing beam splitter and transmitting the other therethrough and synthesizing them with each other, and directing the synthesized light to said projection lens system.

6. A projector according to claim 1, wherein said supplying means includes:

a lamp emitting white light;

means for converting said white light into white rectilinearly polarized light; and

an optical system provided with a plurality of dichroic mirrors for taking out said first, second and third lights from said white rectilinearly polarized light.

7. A projector according claim 6, wherein said first, second and third liquid crystal light modulators each reflectively rotates said first, second and third lights, and said supplying means directs said first and second lights each to said first and second liquid crystal light modulators through said first polarizing beam splitter and directs said third light to said third liquid crystal light modulator through said second polarizing beam splitter.

8. A projector according to claim 6, wherein said optical system has a 1/2 wavelength plate in the optical path of said first light for making the plane of polarization of said first light orthogonal to the plane of polarization of said second light.

9. A projector according to any one of claims 1 to 8, wherein said liquid crystal light modulators generate said images by driving the liquid crystal molecules of said liquid crystal light modulators in accordance with video signals of said respective colors.

10. A projector including:

means for supplying first, second and third radiation beams differing in color from one another;

a first light valve for modulating the polarization of said first radiation beam to thereby generate a polarized beam indicative of a first image;

a second light valve for modulating the polarization of said second radiation beam to thereby generate a polarized beam indicative of a second image and having the plane of polarization orthogonal to the plane of polarization of the polarized beam indicative of the first image;

a third light valve for modulating the polarization of said third radiation beam to thereby generate a polarized beam indicative of a third image;

a polarizing beam splitter, disposed where beam paths of said polarized beams from said first and second light valves intersect each other, for directing said polarized beams from said first and second light valves to a common path;

a first projection optical system for receiving said polarized beams generated from said first and second light valves and travelling along said common path from said polarizing beam splitter, and for projecting said first and second images; and

a second projection optical system for receiving said polarized beam from said third light valve to project said third image.

11. A projector according to claim 10, wherein said first projection optical system includes a single projection lens system, and said second projection optical system includes a single projection lens system and a polarizing beam splitter is provided between said projection lens system and said third light valve so as to effect filtering of said polarized beam from said third light valve.

12. A projector according to claim 11, wherein said beam supplying means includes:

a lamp;

an optical system for dividing radiation energy from said lamp into said first, second and third radiation beams to direct them to said first, second and third light valves, respectively; and

means for defining polarization directions of said first, second and third radiation beams.

13. A projector including:

means for supplying first, second and third radiation beams differing in color from one another;

a first light valve for modulating the polarization of said first radiation beam to thereby generate a polarized beam indicative of a first image;

a second light valve for modulating the polarization of said second radiation beam to thereby generate a polarized beam indicative of a second image and polarized in a direction orthogonal to that of said polarized beam indicative of the first image;

directing means having a third light valve for modulating the polarization of said third radiation beam to thereby generate a polarized beam indicative of a third image, for directing said polarized beam indicative of the third image to a first path;

a polarizing beam splitter, disposed where beam paths of said polarized beams from said first and second light valves intersect each other, for directing said polarized beams from said first and second light valves to a second common path;

a dichroic mirror, disposed where said first path and said second path intersect each other, for directing said polarized beams from said first, second and third light valves to a third common path; and

a projection optical system for receiving said polarized beams generated from said first, second and third light valves and travelling along said third common path from said dichroic mirror to project said first, second and third images.

14. A projector according to claim 13, wherein said beam supplying means includes:

a lamp;

an optical system for dividing radiation energy from said lamp into said first, second and third radiation beams to direct them to said first, second and third light valves; and

means for defining polarization directions of said first, second and third radiation beams.

15. A projector according to claim 13, wherein said directing means has a polarizing beam splitter for effecting filtering of said polarized beam indicative of the third image.

16. A projector including:

means for supplying first and second radiation beams differing in color from each other and both polarized in a first direction to different paths, respectively;

a halfwave plate disposed in path of said first radiation beam so as to convert the polarization of said first radiation beam to a second direction orthogonal to said first direction;

a first light valve for modulating the polarization of said first radiation beam from said halfwave plate to thereby generate a polarized beam indicative of a first image;

a second light valve for modulating the polarization of said second radiation beam to thereby generate a polarized beam indicative of a second image and polarized in a direction orthogonal to that of said polarized beam indicative of the first image;

a polarizing beam splitter, disposed where beam paths of said polarized beams from said first and second light valves intersect each other, for directing said polarized beams from said first and second light valves to a common path; and

a projection optical system for receiving said polarized beams generated from said first and second light vales and travelling along said common path from said polarizing beam splitter to project said first and second images.

17. A projector according to claim 16, wherein said beam supplying means includes:

a lamp;

an optical system for dividing radiation energy from said lamp into said first and second radiation beams to direct them to the paths thereof; and

means for defining polarization directions of said first and second radiation beams to said first direction.

18. A projector including:

means for supplying first, second and third radiation beams differing in color from one another;

a first light valve for modulating the polarization of said first radiation beam to thereby generate a polarized beam indicative of a first image;

a second light valve for modulating the polarization of said second radiation beam to thereby generate a polarized beam indicative of a second image and polarized in a direction orthogonal to that of said polarized beam indicative of the first image;

a third light valve for modulating the polarization of said third radiation beam to thereby generate a polarized beam indicative of a third image to direct said polarized beam indicative of the third image to a first path;

a first polarizing beam splitter, disposed where beam paths of said polarized beams from said first and second light valves intersect each other, for directing said polarized beams from said first and second light valves to a second common path;

a second polarizing beam splitter, disposed where said first path and said second path intersect each other, having dichroic characteristic such that filtering of said polarized beam from said third light valve is effected and said polarized beams from said first, second, and third light valves are directed to third common path; and

a projection optical system for receiving said polarized beams generated from said first, second and third light valves and travelling along said third common path from said second polarizing beam splitter to project said first, second and third images.

19. A projector according to claim 18, wherein said beam supplying means includes:

a lamp;

an optical system for dividing radiation energy from said lamp into said first, second and third radiation beams to direct them toward said first, second and third light valves, respectively; and

means for defining polarization directions of said first, second and third radiation beams.

20. A projector including:

means for supplying first, second and third polarized radiation beams differing in color from one another;

a halfwave plate for causing the polarization direction of said first radiation beam and the polarization direction of said second and third radiation beams to be orthogonal each other;

directing means having a first light valve for modulating the polarization of said first radiation beam from said halfwave plate to thereby generate a polarized beam indicative of a first image, for directing said polarized beam indicative of the first image toward a first path;

a second light valve for modulating the polarization of said second radiation beam to thereby generate a polarized beam indicative of a second image and polarized in a direction orthogonal to that of said polarized beam indicative of the first image;

a third light valve for modulating the polarization of said third radiation beam to thereby generate a polarized beam indicative of a third image and polarized in a direction orthogonal to that of said polarized beam indicative of the first image;

a dichroic mirror, disposed where beam paths of said polarized beams from said second and third light valves intersect each other, for directing said polarized beams from said first and second light valves toward a second common path;

a beam splitter, disposed where said first path and said second path intersect each other, for directing said polarized beams from said first, second and third light valves toward a third common path; and

a projection optical system for receiving said polarized beams generated from said first, second and third light valves and travelling along said third path from said second polarizing beam splitter to project said first, second and third images.

21. A projector including:

means for supplying first, second and third polarized radiation beams differing in color from one another;

a halfwave plate for causing the polarization direction of said first radiation beam and the polarization direction of said second and third radiation beams to be orthogonal to each other;

a first light valve for modulating the polarization of said first radiation beam to thereby generate a polarized beam indicative of a first image;

a second light valve for modulating the polarization of said second radiation beam to thereby generate a polarized beam indicative of a second image and polarized in a direction orthogonal to that of said polarized beam indicative of the first image;

a third light valve for modulating the polarization of said third radiation beam to thereby generate a polarized beam indicative of a third image and polarized in a direction orthogonal to that of said polarized beam indicative of the first image, and for directing said polarized beam indicative of the third image toward a first path;

a first polarizing beam splitter, disposed where beam paths of said polarized beams from said first and second light valves intersect each other, for directing said polarized beams from said first and second light valves toward a second common path;

a second polarizing beam splitter, disposed where said first path and said second path intersect each other, having a dichroic characteristic such that filtering of said polarized beam from said third light valve is effected and said polarized beams from said first, second and third light valves are directed toward a third common path; and

a projection optical system for receiving said polarized beams generated from said first, second and third light valves and travelling along said third path from said second polarizing beam splitter to project said first, second and third images.

22. A projector including:

means for supplying first, second and third polarized radiation beams differing in color from one another;

a halfwave plate for causing the polarization direction of said first radiation beam and the polarization direction of said second and third radiation beams to be orthogonal to each other;

a first light valve for modulating the polarization of said first radiation beam to thereby generate a polarized beam indicative of a first image;

a second light valve for modulating the polarization of said second radiation beam to thereby generate a polarized beam indicative of a second image and polarized in a direction orthogonal to that of said polarized beam indicative of the first image;

a third light valve for modulating the polarization of said third radiation beam to thereby generate a polarized beam indicative of a third image and polarized in a direction orthogonal to that of said polarized beam indicative of the first image, and for directing said polarized beam indicative of the third image toward a first path;

a first polarizing beam splitter, disposed where beam paths of said polarized beams from said first and second light valves, for directing said polarized beams from said first and second light valves toward a second common path;

a dichroic mirror, disposed where said first path and said second path intersect each other, for directing said polarized beams from first, second and third light valves toward a third common path; and

a projection optical system for receiving said polarized beams generated from said first, second and third light valves and travelling along said third path from said dichroic mirror to project said first, second and third images.