System and Method for Display Illumination

• US 20090059336A1
• Filed: 08/30/2007
• Published: 03/05/2009
• Est. Priority Date: 08/30/2007
• Status: Abandoned Application

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Farris, Jeffrey Scott, Grasser, Regis, Dunphy, James Christopher, Shi, Hongqin
• Application Number:
  US11/848,022
• Publication Number:
  US 20090059336A1
• Time in Patent Office: Days
• US Class Current: 359/199.100
• CPC Class Codes: G02B 26/008 in the form of devices for effecting sequential colour changes, e.g. colour wheels
• CPC Class Codes: G02B 26/0875 by means of one or more refracting elements

Abstract

System and method for increasing display brightness in laser illuminated display systems. An illumination source includes a light source to produce light, a disk having a set of lens elements arranged in a circular ring around a center of the disk, a motor coupled to the disk, and an external lens positioned in a light path of the coherent light source. As the disk rotates, the lens elements are moved sequentially through the light, angularly deflecting the light, which may be corrected by the external lens into a spatial deflection. The spatially deflected light may be used to simultaneously illuminate a surface with more than one color of light, thereby increasing the brightness of the light source.

Claims

1. An illumination source comprising:

a light source to produce light;

a disk having a first set of lens elements arranged in a first circular ring around a center of the disk, each lens element periodically optically coupled to the light source, the disk to move the lens elements in the first set of lens elements sequentially through the light;

a motor coupled to the disk, the motor to rotate the disk; and

an external optical element positioned in a light path of the light source after the disk, the external optical element to convert an angular refraction of the light into a spatial deflection.

2. The illumination source of claim 1, wherein the light source produces multiple beams of different colored light, and wherein the light source is arranged so that the beams of different colored light are incident on the lens elements in the first set of lens elements at distinct locations.

3. The illumination source of claim 2, wherein the distinct locations are all substantially equidistant from the center of the disk.

4. The illumination source of claim 1, wherein the disk further comprises a set of second lens elements, the second lens elements arranged in a second circular ring around the center of the disk.

5. The illumination source of claim 4, wherein the lens elements in the first set of lens elements are a first distance from the center of the disk and the second lens elements in the set of second lens elements are a second distance from the center of the disk, and wherein the first distance is different from the second distance.

6. The illumination source of claim 5, wherein the light source produces multiple beams of different colored light, and wherein the light source is arranged so that at least one beam of colored light is incident on the first set of lens elements and at least another beam of colored light is incident on the set of second lens elements.

7. The illumination source of claim 1, wherein each of the lens elements in the first set of lens elements has a surface that is acylindrical, parabolic, and combinations thereof.

8. The illumination source of claim 7, wherein the lens elements have a cross-section along a radial coordinate may be expressed as:

Z=A+B*Y²+C*X*Y²,

where Y is a Cartesian coordinate tangential to a circumference of the disk, X is a radial coordinate, and A, B, and C are coefficients, and wherein C is set to be substantially equal to

−

B/Rcenter,

where Rcenter is a radius of a center beam.

9. The illumination source of claim 7, wherein the lens elements have a cross-section along a radial coordinate may be expressed as:

Z=A+B*Y²+C*X*Y²,

where Y is a Cartesian coordinate tangential to a circumference of the disk, X is a radial coordinate, and A, B, and C are coefficients, and wherein C is set to be substantially equal to

−

2*B/Rcenter,

where Rcenter is a radius of a center beam.

10. The illumination source of claim 1, wherein the disk and the first set of lens elements are created from a material selected from the group consisting of:

polymethylmethacrylate, polycarbonate, glass, polystyrene, cyclic olefin copolymer, cyclic olefin polymer, and combinations thereof.

11. The illumination source of claim 1, wherein the lens elements in the first set of lens elements are coated with a coating selected from the group consisting of:

an antireflective coating, a neutral density filter coating, and combinations thereof.

12. The illumination source of claim 11, wherein the neutral density filter coating is applied to only a subset of lens elements in the first set of lens elements.

13. The illumination source of claim 1, wherein the lens elements in the first set of lens elements have a reflective coating on a curved side of the lens elements.

14. The illumination source of claim 1, wherein the lens elements in the first set of lens elements have a greater refractive power along a first optical axis than along a second optical axis, with the first optical axis and the second optical axis being orthogonal to the light path.

15. A display system comprising:

an illumination source, the illumination source comprising,

a light source to produce light,

a rotatable disk having a set of lens elements arranged in a circumference around a center of the disk with each lens element equidistant from a center of the disk, the circumference in a light path of the light source, the disk to move the lens elements in the set of lens elements through the light,

an optical element positioned in a light path of the light source after the light source, the optical element to expand the light along an axis perpendicular to the light path, and

an external lens positioned in a light path of the light source after the disk, the external lens to convert an angular refraction of the coherent light by the lens elements into a spatial deflection;

a microdisplay optically coupled to the illumination source and positioned in a light path of the illumination source after the illumination source, the microdisplay configured to produce images by modulating light from the illumination source based on image data; and

a controller electronically coupled to the microdisplay and to the illumination source, the controller configured to load image data into the microdisplay.

16. The display system of claim 15, wherein the disk has multiple sets of lens elements, with lens elements of each set of lens elements arranged in a circular ring with a distinct radius from the center of the disk.

17. The display system of claim 15, wherein the optical element is positioned in the light path of the light source and either before the disk or after the disk.

18. The display system of claim 15, wherein the light source further comprises a synchronization unit to synchronize the disk and the controller, the synchronization unit comprising:

an index mark located on the disk; and

a sensor coupled to the disk and to the controller, the sensor to detect the index mark and provide information related to the index mark to the controller.

19. 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,

installing a rotatable disk having a set of lens elements arranged along a circumference around a center of the disk, a light path of the coherent light source intersecting the circumference,

installing a motor to rotate the disk, and

installing an external lens in the light path after the disk;

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

installing a controller configured to control the light source and the microdisplay; and

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

20. The method of claim 19, wherein the disk with the set of lens elements is manufactured by injection molding.