Thin illumination system

• US 8,740,439 B2
• Filed: 12/21/2012
• Issued: 06/03/2014
• Est. Priority Date: 01/30/2008
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Holman, Robert L., Sampsell, Matthew B.
• Primary Examiner(s): Mai, Anh
• Assistant Examiner(s): Breval, Elmito
• Application Number:
  US13/725,864
• Publication Number:
  US 20130107572A1
• Time in Patent Office: 529 Days
• Field of Search: 362608-610, 362/621, 315/169.1, 315/169.3
• US Class Current: 362/609
• CPC Class Codes: F21K 9/23 Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
• CPC Class Codes: F21K 9/61 using light guides
• CPC Class Codes: F21S 8/04 intended only for mounting on a ceiling or the like overhead structures F21S8/02 takes precedence; details of ceiling bases F21V21/03
• CPC Class Codes: F21V 2200/20 of light guides of a generally planar shape
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 29/80 with pins or wires
• CPC Class Codes: F21W 2131/10 Outdoor lighting
• CPC Class Codes: F21Y 2105/00 Planar light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 6/0011 the light guides being planar or of plate-like form
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0035 provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0078 Side-by-side arrangements, e.g. for large area displays
• CPC Class Codes: G02B 6/0083 Details of electrical connections of light sources to drivers, circuit boards, or the like
• CPC Class Codes: G02B 6/0085 Means for removing heat created by the light source from the package heat extraction or cooling elements for semiconductor light sources in general H01L33/64

Abstract

The present invention introduces a new class of thin doubly collimating light distributing engines for use in a variety of general lighting applications. Output illumination from these slim-profile illumination systems whether square, rectangular or circular in physical aperture shape is directional, square, rectangular or circular in beam cross-section, and spatially uniform and sharply cutoff outside the system'"'"'s adjustable far-field angular cone. Some embodiments provided include thin light distributing engines which provide input light collimated in one meridian and a light distributing element that maintains input collimation while collimating output light in the un-collimated orthogonal meridian, in such a manner that the system'"'"'s far-field output light is collimated in both its orthogonal output meridians. The present invention can also include optical films that process the engine'"'"'s doubly collimated output illumination so as to increase its angular extent one or both output meridians without changing beam shape or uniformity.

Claims

1. An illuminating system, comprising:

a single LED emitter having a square or rectangular emitting aperture that is d1 by d2;

a four sided etendue preserving angle transforming reflector whose input aperture is disposed adjacent to the output emitting aperture of the single LED emitter receiving LED emission;

a light guiding pipe whose input aperture receives light from an output aperture of the etendue preserving angle transforming reflector element, the light guiding pipe comprising

a tapered light guide bar having rectangular cross-section and a light guiding pipe refraction index,

a first optical film having a first optical film refractive index different than the light guiding pipe refraction index, and

a first prismatic lens sheet having a first prismatic lens sheet refractive index and a specularly reflecting coating deposited upon facets of the first prismatic lens sheet, the first optical film provided between the tapered light guide bar and the first prismatic lens sheet; and

a light guiding plate one edge of which is disposed adjacent to a rectangular edge of the light guiding pipe.

2. The illuminating system of claim 1 wherein the four sided etendue preserving angle transforming reflector transforms the LED'"'"'s wide angle output emission to output light passing through its output aperture in both meridians of the light guiding pipe with an angular extent substantially equaling +/−

θ

, where +/−

θ

is determined by the applicable etendue preserving Sine Law, θ

=Sin<sup>−

1</sup>(d_i/D_i), where D_i and d_i refer to the input and output aperture dimensions in each meridian.

3. The illuminating system of claim 1, wherein the light guiding pipe provides evenly distributed output light along the rectangular edge, collimated in one meridan.

4. The illuminating system of claim 1, further comprising one or more lenticular lens sheets disposed beyond a rectangular output face of the light guiding plate, their lenticules facing towards the rectangular output face.

5. The illuminating system of claim 4 wherein the one or more lenticular lens sheets contain parabollically-shaped lenticules.

6. The illuminating system of claim 4 wherein the one or more lenticular lens sheets are oriented with respect to each other such that their lenticular lens axes are substantially orthogonal to each other.

7. The illuminating system of claim 1 having one or more diffuser sheets disposed beyond a rectangular output face of the light guiding plate.

8. The illuminating system of claim 1 wherein an input aperture of the light guiding plate is covered completely or partially by a lenticular lens film whose plane surface is disposed towards the input aperture and whose lenticular lens axes are aligned either parallel to the edge of the input aperture, or perpendicularly to the edge of the input aperture.

9. The illuminating system of claim 1, wherein the light guiding plate provides an evenly distributed output beam across one rectangular output face, and wherein the system further comprises a tilted plane mirror disposed to receive said the output beam and redirect it in a different angular direction.

10. The illuminating system of claim 1, wherein the first prismatic lens sheet comprises a substantially continuous array of prism lenses each having left hand reflecting facets and right hand reflecting facets, the right hand facets receiving substantially all the incident light.

11. The illuminating system of claim 10 where the total included angle between the right hand facets and the left hand facets is in the range 95 to 105 degrees.

12. The illuminating system of claim 1, wherein the light guiding plate provides an evenly distributed output beam across one rectangular output face.

13. The illuminating system of claim 12, wherein the output beam is substantially square or rectangular in cross-section and well-collimated in both output meridians.

14. The illuminating system of claim 1, further comprising a prismatic lens sheet comprising a substantially continuous array of prism lenses each having left hand reflecting facets and right hand reflecting facets, the right hand facets receiving substantially all the incident light.

15. The illuminating system of claim 14 where the total included angle between right hand facets and left hand facets is in the range 75 to 120 degrees.

16. The illuminating system of claim 1, wherein the light guiding plate comprises one or more of a light guide plate having rectangular cross-section and a light guiding plate refractive index, a tapered light guide plate having rectangular cross-section and a light guiding plate refractive index, a second optical film having a second optical film refractive index, a second prismatic lens sheet having a second prismatic lens sheet refractive index and a specularly reflecting coating deposited upon facets of the second prismatic lens sheet, and a plane specularly-reflecting mirror.

17. An illuminating system, comprising:

a linear array of LED emitters whose center-to-center distance between emitters is W, and each having a square or rectangular output aperture that is d1 by d2;

a substrate circuit comprising means for electrically interconnecting the array of LED emitters;

a linear array of rectangular four sided etendue preserving angle transforming reflectors whose rectangular input apertures are d1 by d2 and have a center-to-center spacing W, each input aperture disposed adjacent to an output aperture of an LED emitter in the array; and

a light guiding plate one edge of which is disposed adjacent to output apertures of the linear array of etendue preserving reflectors, the light guiding plate comprising

a tapered light guide plate having rectangular cross-section and a light guiding plate refractive index,

an optical film having an optical film refractive index different than the light guiding plate refractive index, and

a prismatic lens sheet having a lens sheet refractive index and a specularly reflecting coating deposited upon facets of the prismatic lens sheet, the optical film provided between the tapered light guide plate and the prismatic lens sheet.

18. The illuminating system of claim 17 wherein each of the rectangular four sided etendue preserving angle transforming reflectors in the array of rectangular four sided etendue preserving angle transforming reflectors collimates its output light through its D1 sized output aperture in the meridian parallel to the long axis of a rectangular edge of the light guiding plate with an angular extent in the meridian substantially +/−

θ

1, where +/−

θ

1 is determined by the applicable etendue preserving Sine Law, with θ

1 substantially Sin<sup>−

1</sup>(d1/D1).

19. The illuminating system of claim 18 wherein each of the rectangular four sided etendue preserving angle transforming reflectors in the array of rectangular four sided etendue preserving angle transforming reflectors has its opposing sidewalls shaped mathematically according to the boundary condition of preserving etendue between input aperture and output aperture.

20. The illuminating system of claim 17, the light guiding plate providing an evenly distributed output beam across one rectangular output face, the output substantially square or rectangular in cross-section and well-collimated in both output meridians.