Method of combining dispersed light sources for projection display

• US 7,537,347 B2
• Filed: 11/29/2005
• Issued: 05/26/2009
• Est. Priority Date: 11/29/2005
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Dewald, Duane Scott
• Primary Examiner(s): Dowling; William C
• Application Number:
  US11/288,679
• Publication Number:
  US 20070121085A1
• Time in Patent Office: 1,274 Days
• Field of Search: 353/102, 353/97, 353/94, 353 85- 87, 353/119, 353/20, 353/122, 349/69, 349/62, 348798-803, 362559-561, 362/555
• US Class Current: 353/38
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 27/0961 Lens arrays lens arrays per se G02B3/0006
• 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 3/0062 Stacked lens arrays, i.e. refractive surfaces arranged in at least two planes, without structurally separate optical elements in-between
• CPC Class Codes: G03B 21/16 Cooling; Preventing overheating
• CPC Class Codes: G03B 21/208 Homogenising, shaping of the illumination light
• CPC Class Codes: H04N 9/3111 for displaying the colours sequentially, e.g. by using sequentially activated light sources sequential projection in colour photography G03B33/08
• CPC Class Codes: H04N 9/3152 for shaping the light beam beam shaping per se G02B27/09

Abstract

A method and system for combining light emitted by dispersed light sources for use in a projection display or similar system. A plurality of elongated and tapered light integrators are placed side by side forming an array, each having at their small input end a light source, such as an LED. Light collimated by each light integrator is further collimated by a convex lens disposed immediately at the output end of the light integrator. From the convex lenses, the light falls upon an array integrator, preferably a fly-eye type integrator, and passes through it to a second array integrator. Light emerging from the second array integrator is then passed through one or more relay lenses and falls upon a light modulator, such as a digital mircomirror device (DMD). The modulated light beam then passes through a projection lens and onto a visual image display screen. The display screen may, for example, be the screen of a high definition television (HDTV).

Claims

1. A method for combining light from a plurality of dispersed sources, said method comprising the steps of:

integrating the light emitted by each light source in the plurality of light sources in an elongated light source integrator having an input end and an output end;

providing a convex lens at the output end of each light source integrator for collimating an emergent light beam;

receiving the light collimated by the convex lenses at a first array integrator, wherein the light collimated by the convex lenses is always directed towards the first array integrator; and

receiving the light passing through the first array integrator at a second array integrator.

2. The method according to claim 1, further comprising the steps of:

modulating the light passing through the second array integrator to form a visual image; and

displaying the visual image on a display screen.

3. The method according to claim 2, wherein the modulating step is performed by a digital mirromirror device (DMD).

4. The method according to claim 2, wherein the modulated light passes through a projection lens prior to the displaying step.

5. The method according to claim 2, wherein the light passing through the second array integrator passes through at least one relay lens prior to the modulating step.

6. The method according to claim 1, wherein the first array integrator and the second array integrator are both fly-eye integrators.

7. The method according to claim 6, wherein the first array integrator and the second array integrator are effectively identical.

8. The method according to claim 7, wherein each of the fly-eye integrators comprise a plurality of rectangular facets.

9. The method according to claim 8, wherein each of the light source integrators is tapered, with the output being at the larger end.

10. The method according to claim 9, wherein the light source integrators are rectangular.

11. A display system comprising:

a plurality of light sources aligned in a same plane;

an array of light-source integrators, each light-source integrator of the array for receiving light emitted from one light source of the plurality of light sources;

a plurality of convex lenses, each convex lens being positioned to receive light emitted by a light source after it has passed through the light-source integrator associated with the light source;

a first array integrator positioned to receive light passing through the plurality of convex lenses;

a plurality of light paths between the convex lenses and the first array integrator, each of the plurality of light paths being substantially the same length;

a second array integrator positioned to receive light passing through the first array integrator;

a relay lens positioned to receive light passing through the second array integrator;

a light modulation device to modulate light passing through the relay lens;

a projection lens for receiving light modulated by the light modulation device; and

a visual image display screen for receiving light projected by the projection lens in order to create a visual image.

12. The display system of claim 11, wherein the light sources are arc lamps.

13. The display system of claim 11 wherein the light sources are LEDs.

14. The display system of claim 13, wherein the LED'"'"'s are mounted on a substrate.

15. The display system of claim 11, wherein the light source integrators comprise a small end and a large end, and are adjacent to each other at the large end.