Illumination apparatus and projector

• US 6,089,730 A
• Filed: 10/23/1998
• Issued: 07/18/2000
• Est. Priority Date: 10/27/1997
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Machii, Ritsuo
• Primary Examiner(s): Spyrou, Cassandra
• Assistant Examiner(s): Sikder, Mohammad Y.
• Application Number:
  US09/178,565
• Time in Patent Office: 634 Days
• Field of Search: 362/293, 362/296, 362/302, 362/303, 362/304, 353/61, 353/52, 353/54
• US Class Current: 362/293
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor
• CPC Class Codes: H04N 5/7408 Direct viewing projectors, e.g. an image displayed on a video CRT or LCD display being projected on a screen
• 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 9/3141 Constructional details thereof details not peculiar to the presence of an electronic spatial light modulator G03B21/14
• CPC Class Codes: H04N 9/315 Modulator illumination systems general applications of lighting devices F21V; general optical systems G02B; lamp houses for projectors not peculiar to the presence of an electronic spatial light modulator G03B21/20

Abstract

An illumination apparatus includes a lamp, and a holding member for rotatably holding the lamp about its optical axis as a rotational axis. An projector includes the illumination apparatus, a first optical system for separating white light from the illumination apparatus into light of red, green and blue, a first panel for modulating the light of red per each pixel, a second panel for modulating the light of green per each pixel, a third panel for modulating the light of blue per each pixel, a projection lens, and a second optical system for superimposing the modulated light of red, green and blue on a display surface, such as a screen, in cooperation with the projection lens.

Claims

1. A method for reducing color unevenness in an image projected by a projector, said method comprising the steps of:

obtaining information of the color unevenness on a screen at each rotational position of a lamp when rotating the lamp about its optical axis as a rotational axis, wherein said optical axis passes through said lamp; and

seeking the rotational position at which the color unevenness is most reduced, based on the information of the color unevenness.

2. A method according to claim 1, the lamp being rotated being held by a rotatable holding member.

3. A method according to claim 2, the lamp including a light radiation tube and a concave mirror.

4. A method according to claim 3, the concave mirror including an ellipsoidal mirror or a parabolic mirror.

5. A method according to claim 1, wherein the projector includes a first optical system for separating white light from the lamp into light of red, green and blue, a first panel for modulating the light of red per each pixel, a second panel for modulating the light of green per each pixel, a third panel for modulating the light of blue per each pixel, a projection lens, and a second optical system for superimposing the modulated light of red, green and blue in projected image, such as that displayed on a screen, in cooperation with a projection lens.

6. A method according to claim 2, wherein the projector includes a first optical system for separating white light from the lamp into light of red, green and blue, a first panel for modulating the light of red per each pixel, a second panel for modulating the light of green per each pixel, a third panel for modulating the light of blue per each pixel, a projection lens, and a second optical system and a second optical system for superimposing the modulated light of red, green and blue in a projected image, such as that displayed on a screen, in cooperation with a projection lens.

7. A method according to claim 3, wherein the projector includes a first optical system for separating white light from the lamp into light of red, green and blue, a first panel for modulating the light of red per each pixel, a second panel for modulating the light of green per each pixel, a third panel for modulating the light of blue per each pixel, a projection lens, and a second optical system for superimposing the modulated light of red, green and blue in a projected image, such as that displayed on a screen, in cooperation with a projection lens.

8. A method according to claim 4, wherein the projector includes a first optical system for separating white light from the lamp into light of red, green and blue, a first panel for modulating the light of red per each pixel, a second panel for modulating the light of green per each pixel, a third panel for modulating the light of blue per each pixel, a projection lens, and a second optical system for superimposing the modulated light of red, green and blue in a projected image, such as that displayed on a screen, in cooperation with a projection lens.

9. A method according to claim 5, wherein the first, second and third panels include liquid crystal display elements, respectively.

10. A method according to claim 6, wherein the first, second and third panels include liquid crystal display elements, respectively.

11. A method according to claim 7, wherein the first, second and third panels include liquid crystal display elements, respectively.

12. A method according to claim 8, wherein the first, second and third panels include liquid crystal display elements, respectively.

13. A method for reducing color unevenness in an image projected by a projector, said method comprising the steps of:

obtaining information of the color unevenness on a plane on which said image is projected, at each rotational position of a lamp when rotating the lamp about its optical axis as a rotational axis, wherein said optical axis passes through said lamp; and

seeking the rotational position at which the color unevenness is most reduced, based on the information of the color unevenness.