System and Method for Uniform Light Generation

• US 20090262307A1
• Filed: 04/18/2008
• Published: 10/22/2009
• Est. Priority Date: 04/18/2008
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Bartlett, Terry Alan, Rancuret, Paul L.
• Granted Patent: US 7,972,004 B2
• Time in Patent Office: Days
• US Class Current: 353/31
• CPC Class Codes: G02B 26/12 using multifaceted mirrors
• CPC Class Codes: G02B 27/1033 having a single light modulator for all colour channels
• CPC Class Codes: G02B 27/104 for use with scanning systems scanning systems G02B26/10
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G02B 3/005 arranged along a single direction only, e.g. lenticular sheets G02B3/0043 takes precedence
• 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: G03B 33/08 Sequential recording or projection G03B33/02, G03B33/04, G03B33/06 take precedence
• CPC Class Codes: H04N 9/3117 by using a sequential colour filter producing two or more colours simultaneously, e.g. by creating scrolling colour bands
• 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

A system and method for uniform light generation in projection display systems. An illumination source comprises a light source to produce colored light, and a scrolling optics unit optically coupled to the light source, the scrolling optics unit configured to create lines of colored light from the colored light, and to scroll the lines of colored light along a direction orthogonal to a light path of the illumination source. The scrolling optics unit comprises a single light shaping diffuser to transform the colored light into the lines of colored light, an optical filter positioned in the light path after the light shaping diffuser, and a scrolling optics element positioned in the light path after the optical filter. The single light shaping diffuser is capable of simultaneously transforming colored light into lines of colored light having substantially uniform intensity to provide uniform illumination.

Claims

1. An illumination source comprising:

a light source to produce colored light; and

a scrolling optics unit optically coupled to the light source, the scrolling optics unit configured to create lines of colored light from the colored light, and to scroll the lines of colored light along a direction orthogonal to a light path of the illumination source, wherein the scrolling optics unit comprises,

a single light shaping diffuser to transform the colored light into the lines of colored light,

an optical filter positioned in the light path after the light shaping diffuser, the optical filter configured to shape the lines of colored light, and

a scrolling optics element positioned in the light path after the optical filter, the scrolling optics element configured to move the lines of colored light in the direction orthogonal to the light path.

2. The illumination source of claim 1, wherein the scrolling optics element is selected from the group consisting of:

a rotating reflective polygon, a rotating refractive polygon, a flower wheel, and combinations thereof.

3. The illumination source of claim 2 further comprising a motor coupled to the scrolling optics element, the motor configured to rotate the scrolling optics element.

4. The illumination source of claim 1, wherein the light source comprises:

a set of coherent light sources, each coherent light source configured to produce colored light in a specified wavelength range; and

a set of light collimators, each light collimator optically coupled to a coherent light source in the set of coherent light sources, the light collimator to substantially parallelize coherent light produced by a corresponding coherent light source.

5. The illumination source of claim 1, wherein the scrolling optics unit further comprises a speckle reduction optical element positioned in the light path, the speckle reduction optical element configured to reduce a visual impact of modulating spatial noise.

6. The illumination source of claim 1, wherein the light shaping diffuser is capable of substantially simultaneously transforming colored light from the light source into lines of colored light.

7. The illumination source of claim 6, wherein the light shaping diffuser comprises light diffusing structures oriented in a direction orthogonal to an orientation of the lines of colored light.

8. The illumination source of claim 7, wherein the light shaping diffuser comprises an array of lenticular elements, and wherein the array has a pitch substantially greater than a longest light wavelength produced by the light source.

9. The illumination source of claim 7, wherein the light shaping diffuser comprises randomly or pseudorandomly arranged structures having consistent orientation, and wherein each structure has a feature size substantially greater than a longest light wavelength produced by the light source.

10. The illumination source of claim 1, wherein the optical filter comprises an optically opaque body having multiple slit apertures, wherein the slit apertures shape a line of colored light passing through the slit aperture, wherein there is a slit aperture corresponding to each color of light produced by the light source.

11. The illumination source of claim 10, wherein the optical filter further comprises multiple color filters, wherein there is one color filter for each slit aperture, wherein each color filter blocks light wavelengths outside of an intended range of light wavelengths for a line of colored light passing through the slit aperture.

12. A method comprising:

generating spots of colored light;

focusing the spots of colored light on a single diffuser;

generating lines of colored light from the spots of colored light;

filtering the lines of colored light; and

scrolling the filtered lines of colored light.

13. The method of claim 12, wherein the generating lines of colored light comprises passing the spots of colored light through a single reflective or refractive diffuser having an array of lenticular elements or a random or pseudorandom arrangement of structures.

14. The method of claim 12, wherein the filtering the lines of colored light comprises:

shape filtering the lines of colored light to produce lines of desired shape; and

color filtering the lines of colored light to reduce light contamination.

15. The method of claim 14, wherein the shape filtering and the color filtering are applied to each line in the lines of colored light individually.

16. A method of manufacturing a display system, the method comprising:

installing a light source configured to generate coherent light, wherein the light source installing comprises

installing a coherent light source to produce colored light,

installing a light shaping diffuser in a light path of the coherent light source, the light shaping diffuser to substantially simultaneously transform the colored light into lines of colored light,

installing a filter in the light path of the coherent light source, the filter to shape the lines of colored light, and

installing a scrolling optics element in the light path of the coherent light source after the filter, the scrolling optics element to scroll the lines of colored light;

installing a microdisplay in a light path of the display system after the light source;

installing a controller configured to control the light source, the scrolling optics element, and the microdisplay; and

installing a display plane in the light path of the display system after the microdisplay.

17. The method of claim 16, wherein the light shaping diffuser is manufactured by machining or molding.

18. The method of claim 16, wherein the light shaping diffuser comprises light diffusing structures and a body, wherein the light diffusing structures and the body are manufactured in separate manufacturing steps, and wherein the light diffusing structures are attached to the body using an adhesive or a glue.

19. The method of claim 16, wherein the light shaping diffuser is manufactured from a material selected from the group consisting of:

glass, plastic, polymethylmethacrylate (PMMA), polycarbonate, polyester, mylar, acrylic, polymethyl-pentene, and combinations thereof.

20. The method of claim 16, wherein the filter comprises an optically opaque body having multiple slit apertures, and wherein the filter is manufactured by machining the multiple slit apertures in the optically opaque body.