High-density illumination system

• US 7,210,806 B2
• Filed: 03/23/2005
• Issued: 05/01/2007
• Est. Priority Date: 01/24/2003
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Digital Optics International Corporation
• Inventors: Holman, Robert L., Cox, Arthur
• Primary Examiner(s): Husar; Stephen F
• Application Number:
  US11/089,314
• Publication Number:
  US 20050185419A1
• Time in Patent Office: 769 Days
• Field of Search: 362242-245, 362/328, 362/331, 362/545, 362/800, 362/19, 362/299, 362/302, 362/308
• US Class Current: 362/19
• CPC Class Codes: F21K 9/68 Details of reflectors forming part of the light source
• CPC Class Codes: G02B 17/002 Arrays of reflective systems
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02B 5/10 with curved faces
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/13 of an individual bump connector
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/12044 OLED
• CPC Class Codes: H01L 2933/0091 : Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/58 : Optical field-shaping elements
• CPC Class Codes: H01L 33/60 : Reflective elements
• 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
• CPC Class Codes: Y10S 362/80 : Light emitting diode

Abstract

A compact and efficient optical illumination system featuring planar multi-layered LED light source arrays concentrating their polarized or un-polarized output within a limited angular range. The optical system manipulates light emitted by a planar array of electrically-interconnected LED chips positioned within the input apertures of a corresponding array of shaped metallic reflecting bins using at least one of elevated prismatic films, polarization converting films, micro-lens arrays and external hemispherical or ellipsoidal reflecting elements. Practical applications of the LED array illumination systems include compact LCD or DMD video image projectors, as well as general lighting, automotive lighting, and LCD backlighting.

Claims

1. An illuminating system, comprising:

an electrical interconnection system for interconnecting at least one LED chip to a power source;

a plurality of LED chips spaced apart from one another a distance S less than or equal to a width W of said LED chip;

an array of reflecting bins with each of said bins comprising a clear output aperture and a clear input aperture;

a first light redirecting means disposed beyond said array of metallically reflecting bins that transmits light in a first angular range and reflects light in a second angular range back towards said array of bins;

a second light redirecting means disposed beyond said first light redirecting means that transmits light in a first angular range and reflects light in a second angular range back towards said first light redirecting means; and

said array of metallically reflecting bins disposed above said interconnection plate and each of said LED chips extends through a center of the input aperture.

2. An illuminating system, comprising:

an electrical interconnection system for interconnecting at least one LED light emitting element to a power source;

at least one LED light emitting element positioned on a common light-emitting plane;

a first light redirecting element disposed above the at least one LED light-emitting element on said common light emitting plane, each said first light redirecting element including at least one diffusing medium, a diffusing layer, and a component selected from the group of a metallically reflecting bin and a lens system;

a second light redirecting element disposed beyond said common light emitting plane substantially at a distance value F, said second light redirecting element comprised of at least one condensing element having an effective focal length of the value F, coaxial with a center of said common light emitting plane and a dichroic color mixing system designed to pass light of one color band, while redirecting light of another color band;

a third light redirecting element disposed above said common light emitting plane a distance being selected from the group of said effective focal length F and twice said effective focal length F, said third light redirecting element comprising a combination of at least one of a reflective polarizer and a quarter-wave phase retardation film, the combination transmitting light outwards in a first polarization state and reflecting light backwards in a second polarization state orthogonal to said first polarization state;

a fourth light redirecting element disposed beyond said second and third light redirecting element and reflecting light backwards towards a centroid area of said second light redirecting component; and

an output aperture disposed beyond said third light redirecting element, said output aperture containing at least one of a clear window and a spatial light modulator.

3. The illuminating system as defined in claim 2 wherein the first light redirecting element comprises metallically reflecting bins having a clear output aperture and a clear input aperture formed by at least one mathematically-tapered metallically reflecting sidewall extending therebetween, centers of each said metallically reflecting bin being centered on a center of a corresponding one of the LED light emitting element.

4. The illuminating system as defined in claim 2 wherein said first light redirecting element comprises at least one of lenses and systems of lenses centered on the center of a corresponding one of the LED light emitting element.

5. The illuminating system as defined in claim 2 wherein said first light redirecting element comprises at least one of a passive diffuser and active diffuser including a transparent phase holding secondary diffuser spherical particles that fluoresce and/or scatter the light passing through the particles, the center of each said passive and active diffuser centered on a center of the corresponding one of the LED light emitting element.

6. The illuminating system as defined in claim 2 wherein said second light redirecting element comprises at least one Fresnel lens of effective focal length F.

7. The illuminating system as defined in claim 2 wherein said third light redirecting element contains at least one of a reflective polarizer, a wire-grid reflective polarizer and a quarter-wave phase retardation film.

8. The illuminating system as defined in claim 7 wherein said third light redirecting element is disposed just below said second light redirecting element.

9. The illuminating system as defined in claim 7 wherein said third light redirecting element is disposed a distance above said second light redirecting element approximately equal to said effective focal length F of said second light redirecting element.

10. The illuminating system as defined in claim 2 wherein said fourth light redirecting element comprises a concave metallically-reflecting mirror element, said common light emitting plane fitting within an aperture cut into said concave metallically reflecting mirror at its vertex.

11. The illuminating system as defined in claim 10 wherein said concave metallically reflecting mirror has a radius of curvature approximately equal to twice the effective focal length F of said second light redirecting element.

12. The illuminating system as defined in claim 11 wherein said concave metallically reflecting mirror is positioned to receive polarized light redirected by said third light redirecting element, maintaining the polarization state of said polarized light and redirecting said light back through said third light redirecting element towards said centroid region of said common light emitting plane for reuse of said light.

13. The illuminating system as defined in claim 2 wherein said fourth light redirecting element comprises a metallically-reflecting cylindrical mirror element whose cylindrical axis is centered on said centroid region of said common light emitting plane, and whose reflecting surface is the interior surface of said metallically-reflecting cylindrical mirror.

14. The illuminating system as defined in claim 13 wherein the interior surface of said metallically-reflecting cylindrical mirror contains a physical reflecting structure, the physical reflecting structure redirecting collected light back towards said centroid region of said common light emitting plane.

15. The illuminating system as defined in claim 14 wherein said physical reflecting structure is composed of a series of concentric reflecting rings, one of the rings stacked upon the next, each of said reflecting rings being a zonal portion of convex hemispherical mirror whose radius of curvature is that which centers on the centroid region of said common light emitting plane.

16. The illuminating system as defined in claim 15 wherein light emitted by said common light emitting plane that is not received by said second light redirecting element is collected by said concentric reflecting rings and reflected backwards and recycled towards said centroid region of said common light emitting plane for the purpose of reuse.

17. The illuminating system as defined in claim 14 wherein said physical reflecting structure is composed of a series of corner cube retro reflectors, each designed to return collected light back in the general direction it came from, towards said centroid region of said common light emitting plane.

18. The illuminating system as defined in claim 2 wherein said output aperture is disposed a distance above said second light redirecting element greater than or equal to said effective focal length of said second light redirecting element.

19. The illuminating system as defined in claim 18 wherein said output aperture is a reflecting plate having a circular or rectangular cutout that allows for a substantial portion of the emitted light to pass outwards without change in brightness or angular direction.

20. The illuminating system as defined in claim 18 wherein said output aperture comprises a spatial light modulator that allows a substantial portion of the emitted light to pass through said output aperture with outgoing intensity, brightness or angular direction spatially varied by the deliberate pattern imparted by said spatial light modulator.