Device and method for reducing speckle in projected images

• US 8,905,548 B2
• Filed: 08/23/2012
• Issued: 12/09/2014
• Est. Priority Date: 08/23/2012
• Status: Active Grant

• Current Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Original Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Inventors: Fan, Chun-Sheng
• Primary Examiner(s): Ko, Tony
• Assistant Examiner(s): Reilly-Diakun, Jori S
• Application Number:
  US13/593,316
• Publication Number:
  US 20140055755A1
• Time in Patent Office: 838 Days
• Field of Search: 353/20, 353 30- 31, 353/33, 353 37- 38, 353/85, 353/94, 359/245, 359/259, 359/279, 359/707, 349/5, 349 7- 9, 349/64
• US Class Current: 353/31
• CPC Class Codes: G02B 27/1033 having a single light modulator for all colour channels
• CPC Class Codes: G02B 27/149 using crossed beamsplitting surfaces, e.g. cross-dichroic cubes or X-cubes
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements
• CPC Class Codes: G03B 21/147 Optical correction of image distortions, e.g. keystone
• CPC Class Codes: G03B 21/20 Lamp housings
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: G03B 21/208 Homogenising, shaping of the illumination light
• CPC Class Codes: G03B 33/06 by additive-colour projection apparatus
• CPC Class Codes: H04N 9/3161 using laser light sources using laser beams scanning the display screen H04N9/3129

Abstract

An image projector includes a light source for displaying light and a diffusing screen coupled to an in-plane vibrator. The diffusing screen is positioned to receive the display light from the light source and generate phase-modulated display light. The image projector also includes a collimating element positioned to receive the phase-modulated display light. The image projector further includes a display panel positioned to receive the phase-modulated display light after being collimated by the collimating element. The display panel is configured to generate a projectable image using the phase-modulated display light.

Claims

1. An image projector comprising:

first, second, and third light modules, each of the light modules comprising;

a light source; and

a reflective diffusing screen coupled to an in-plane vibrator that includes at least one comb-drive actuator connected to move the reflective diffusing screen in-plane, the reflective diffusing screen including a homogeneous micro-lens array, wherein the reflective diffusing screen is positioned to receive light from the light source and generate phase-modulated light, and wherein the phase-modulated light from the light source of the first light module is a first color light, the phase-modulated light from the light source of the second light module is a second color light, and the phase-modulated light from the light source of the third light module is a third color light;

a dichroic combiner cube coupled to receive and combine the first color light, the second color light, and the third color light into display light;

a collimating element positioned between each of the light modules and the dichroic combiner cube to collimate the first color light, the second color light, and the third color light; and

a display panel positioned to receive the display light, wherein the display panel is configured to generate a projectable image using the display light.

2. The image projector of claim 1, wherein the display panel is a Liquid Crystal On Silicon (“

LCOS”

) panel and the image projector of claim 1 further comprises;

a polarizing beam splitter (“

PBS”

) positioned to direct the display light toward the LCOS panel.

3. The image projector of claim 1, wherein the light source is one of a laser diode, a gas laser, and a solid state laser.

4. The image projector of claim 1, wherein each of the light modules further comprises a lens positioned between the light source and the reflective diffusing screen of each light module.

5. The image projector of claim 1, wherein the reflective diffusing screen includes a transmissive diffusing element laminated to a reflective substrate.

6. An image projector comprising:

a light source for providing display light;

a reflective diffusing screen coupled to an in-plane vibrator that includes at least one-comb drive actuator connected to move the reflective diffusing screen in-plane, the reflective diffusing screen including a homogeneous micro-lens array, wherein the reflective diffusing screen is positioned to receive the display light from the light source and generate phase-modulated display light;

a collimating element positioned to receive the phase-modulated display light; and

a display panel positioned to receive the phase-modulated display light after being collimated by the collimating element, wherein the display panel is configured to generate a projectable image using the phase-modulated display light.

7. The image projector of claim 6, further comprising a lens positioned between the light source and the reflective diffusing screen.

8. The image projector of claim 6, wherein the reflective diffusing screen includes a transmissive diffusing element laminated to a reflective substrate.

9. The image projector of claim 6, wherein the light source comprises:

a first color, second color, and third color light source for providing, respectively, first color light, second color light, and third color light; and

a light combiner optically coupled to combine the first color light, the second color light, and the third color light into the display light.

10. The image projector of claim 9, wherein the light combiner includes a dichroic combiner cube.

11. The image projector of claim 6, wherein the light source is one of a laser diode, a gas laser, and a solid state laser.

12. A method of reducing speckles in a projected image comprising:

providing display light;

phase-modulating the display light, wherein phase-modulating the display light includes positioning a reflective diffusing screen to receive the display light from a light source, wherein the reflective diffusing screen is coupled to an in-plane vibrator that includes at least one-comb drive actuator connected to move the reflective diffusing screen in-plane, the diffusing screen including a homogeneous micro-lens array;

collimating the display light; and

generating a projectable image with the display light using a display panel that receives the display light after the display light has been collimated and phase-modulated.

13. The method of claim 12, wherein providing display light includes combining a first light source, a second light source, and a third light source into the display light, wherein the first light source emits a first color light, the second light source emits a second color light, and the third light source emits a third color light.

14. The method of claim 12, further comprising:

focusing the display light with a lens before phase-modulating the display light.

15. The method of claim 12, further comprising:

directing the display light to the display panel with a polarizing beam splitter (“

PBS”

), wherein the display panel is a Liquid Crystal On Silicon (“

LCOS”

) display.