LIuminating optical device in image display device and image display device

• US 20040257664A1
• Filed: 03/10/2004
• Published: 12/23/2004
• Est. Priority Date: 07/11/2002
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kikuchi, Hiroki, Hashimoto, Shigeki, Oka, Michio
• Granted Patent: US 7,433,126 B2
• Time in Patent Office: Days
• US Class Current: 359/636
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0057 in the form of a laser diode array, e.g. laser diode bar semiconductor laser arrays with beam combining arrangement H01S5/4012
• CPC Class Codes: G02B 2207/117 Adjustment of the optical path length
• CPC Class Codes: G02B 27/1033 having a single light modulator for all colour channels
• 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 27/143 using macroscopically faceted or segmented reflective surfaces
• CPC Class Codes: G02B 27/144 using partially transparent surfaces without spectral selectivity G02B27/147 takes precedence
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: H04N 9/3129 scanning a light beam on the display screen scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161

Abstract

Speckle noise is reduced to increase image quality in an image display apparatus such as a projection display or the like.

An illuminating optical device in an image display apparatus (1) applies a laser beam L to a GLV (spatial modulator) (6) and modulates the laser beam based on an image signal input to the GLV to display an image. A plurality of laser beams (1, 1, . . . ) each having an optical path difference greater than the coherence length of the laser beam are applied to the GLV.

Claims

1. An illuminating optical device in an image display apparatus for applying a laser beam to a spatial modulator and modulating the laser beam based on an image signal input to the spatial modulator to display an image, characterized in that

a plurality of laser beams, each laser beam having an optical path difference greater than a coherence length, are applied to said spatial modulator.

2. The illuminating optical device in an image display apparatus according to claim 1, characterized by a multiple reflection plate including a parallel flat plate which has confronting parallel surfaces with a total reflection surface formed on one of the confronting parallel surfaces and a semi-transmissive reflection surface having a predetermined transmittance formed on the other of the confronting parallel surfaces, the arrangement being such that a laser beam is introduced into the multiple reflection plate at a predetermined incident angle from an entrance window which is formed by removing a portion of the total reflection surface, wherein the laser beam undergoes multiple reflections in the multiple reflection plate, and is partly emitted from the semi-transmissive reflection surface, so that a single laser beam is separated into said plurality of laser beams.

3. The illuminating optical device in an image display apparatus according to claim 1, characterized in that the laser beams are applied to said spatial modulator at different optical axis angles.

4. The illuminating optical device in an image display apparatus according to claim 2, characterized in that the laser beams are applied to said spatial modulator at different optical axis angles.

5. The illuminating optical device in an image display apparatus according to claim 1, characterized in that said spatial modulator is a grating light valve.

6. The illuminating optical device in an image display apparatus according to claim 2, characterized in that said spatial modulator is a grating light valve.

7. The illuminating optical device in an image display apparatus according to claim 3, characterized in that said spatial modulator is a grating light valve.

8. The illuminating optical device in an image display apparatus according to claim 4, characterized in that said spatial modulator is a grating light valve.

9. An image display apparatus for applying a laser beam to a spatial modulator and modulating the laser beam based on an image signal input to the spatial modulator to display an image, characterized in that

an illuminating optical device for applying a laser beam to the spatial modulator applies a plurality of laser beams, each laser beam having an optical path difference greater than a coherence length, to said spatial modulator.

10. The image display apparatus according to claim 9, characterized by a multiple reflection plate including a parallel flat plate which has confronting parallel surfaces with a total reflection surface formed on one of the confronting parallel surfaces and a semi-transmissive reflection surface having a predetermined transmittance formed on the other of the confronting parallel surfaces, the arrangement being such that a laser beam is introduced into the multiple reflection plate at a predetermined incident angle from an entrance window which is formed by removing a portion of the total reflection surface, wherein the laser beam undergoes multiple reflections in the multiple reflection plate, and is partly emitted from the semi-transmissive reflection surface, so that a single laser beam is separated into said plurality of laser beams.

11. The illuminating optical device in an image display apparatus according to claim 9, characterized in that the laser beams are applied to said spatial modulator at different optical axis angles.

12. The illuminating optical device in an image display apparatus according to claim 10, characterized in that the laser beams are applied to said spatial modulator at different optical axis angles.

13. The illuminating optical device in an image display apparatus according to claim 9, characterized in that said light modulator is a grating spatial valve.

14. The illuminating optical device in an image display apparatus according to claim 10, characterized in that said light modulator is a grating spatial valve.

15. The illuminating optical device in an image display apparatus according to claim 11, characterized in that said light modulator is a grating spatial valve.

16. The illuminating optical device in an image display apparatus according to claim 12, characterized in that said light modulator is a grating spatial valve.