Light guide illumination device for direct-indirect illumination

• US 10,495,807 B2
• Filed: 02/12/2018
• Issued: 12/03/2019
• Est. Priority Date: 09/17/2013
• Status: Active Grant

• Current Assignee: Quarkstar LLC
• Original Assignee: Quarkstar LLC
• Inventors: York, Allan Brent, Schinagl, Ferdinand, Dau, Wilson, Lerman, Louis, Stormberg, Hans Peter
• Primary Examiner(s): Carter, William J
• Application Number:
  US15/894,713
• Publication Number:
  US 20190018182A1
• Time in Patent Office: 659 Days
• Field of Search: 362600-634
• CPC Class Codes: F21K 9/61 using light guides
• CPC Class Codes: F21S 8/026 intended to be recessed in a ceiling or like overhead structure, e.g. suspended ceiling
• 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 7/0016 on lighting devices that also provide for direct lighting, e.g. by means of independent light sources, by splitting of the light beam, by switching between both lighting modes
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21Y 2101/00 Point-like light sources
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 19/00 Condensers, e.g. light collectors or similar non-imaging opticsfor microscopes G02B21/08
• 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 6/0031 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 6/0045 by shaping at least a portion of the light guide
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• 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
• CPC Class Codes: G02B 6/0096 the lights guides being of the hollow type

Abstract

An illumination device includes light-emitting elements (LEEs); a light guide extending in a forward direction from a first end to a second end, the light guide being positioned to receive at the first end light emitted by the LEEs and to guide the received light to the second end; and an optical extractor coupled to the second end to receive the guided light. The optical extractor is formed from a transparent, solid material and includes a first output surface including a transmissive portion arranged and shaped to transmit a first portion of the guided light to the ambient in a forward angular range and a reflective portion arranged and shaped to reflect via TIR all the guided light incident on the reflective portion; and a second output surface arranged to transmit, to the ambient in a backward angular range, light reflected by the reflective portion of the first output surface.

Claims

1. An illumination device comprising:

a plurality of light-emitting elements (LEEs);

a light guide extending in a forward direction from a first end of the light guide along an optical axis of the light guide to a second end of the light guide, the light guide being positioned to receive at the first end light emitted by the LEEs and configured to guide the received light to the second end; and

an optical extractor optically coupled to the light guide at the second end to receive the guided light, the optical extractor being formed from a transparent, solid material and comprising;

a first output surface including a transmissive portion arranged and shaped to transmit a first portion of the guided light to the ambient environment in a forward angular range and a reflective portion arranged and shaped to reflect via total internal reflection (TIR) all the guided light incident on the reflective portion, and

a second output surface that is disposed distal from the optical axis, at least a portion of the second output surface being between the first output surface and the plurality of LEEs along the optical axis, the second output surface having a curvilinear profile in a cross-section that includes the forward direction, the second output surface arranged to transmit, to the ambient environment in a backward angular range, light reflected by the reflective portion of the first output surface.

2. The illumination device of claim 1, wherein the reflective portion of the first output surface has a first end and a second end and is arranged to intersect the transmissive portion of the first output surface at the first end and the second output surface at the second end.

3. The illumination device of claim 2, wherein at least one of the transmissive portion or the reflective portion is flat.

4. The illumination device of claim 2, wherein at least one of the transmissive portion or the reflective portion is curved.

5. The illumination device of claim 2, wherein at least one of the transmissive portion or the reflective portion includes a step.

6. The illumination device of claim 2, wherein the transmissive portion intersects the reflective portion at the first end with common surface slope.

7. The illumination device of claim 1, wherein the transmissive portion of the first output surface has a first end and a second end and is arranged to intersect the reflective portion of the first output surface at the first end and the second output surface at the second end.

8. The illumination device of claim 7, wherein at least one of the transmissive portion or the reflective portion is flat.

9. The illumination device of claim 7, wherein at least one of the transmissive portion or the reflective portion is curved.

10. The illumination device of claim 7, wherein at least one of the transmissive portion or the reflective portion includes a step.

11. The illumination device of claim 7, wherein an intersection of the transmissive portion and the reflective portion at the first end forms a kink.

12. The illumination device of claim 1, wherein a relative arrangement of the first and second output surfaces causes light that propagates within the optical extractor to undergo multiple reflections between the first and second output surfaces such that light output into the ambient environment in the forward angular range and/or in the backward angular range has a more uniform intensity distribution or a more uniform color distribution than the guided light at the second end of the light guide.

13. The illumination device of claim 1, wherein the reflective portion of the first output surface is arranged and shaped to reflect via TIR all the guided light incident thereon in a first angular range having a direction with a component antiparallel to the forward direction and a first component orthogonal to the forward direction.

14. The illumination device of claim 13, wherein

the first output surface further includes a second transmissive portion arranged and shaped to transmit a second portion of the guided light to the ambient environment in another forward angular range and a second reflective portion arranged and shaped to reflect via TIR all the guided light incident on the second reflective portion,

the optical extractor further comprises a third output surface having a curvilinear profile in the cross-section that includes the forward direction, the third output surface arranged to transmit, to the ambient environment in another backward angular range, light reflected by the second reflective portion of the first output surface, and

the second reflective portion of the first output surface is arranged and shaped to reflect via TIR all the guided light incident thereof in a second angular range having a direction with a component antiparallel to the forward direction and antiparallel to the first component of the first direction.

15. The illumination device of claim 1, wherein the light guide and the optical extractor are bonded together or integrally formed.

16. The illumination device of claim 1 further comprising one or more optical couplers, wherein

the light provided by the LEEs is in an emission angular range,

the optical couplers are arranged to receive the light provided by the LEEs and redirect it to the first end of the light guide a collimated angular range, and

a numerical aperture of the light guide is such that the light received from the optical couplers in the collimated angular range can be guided by the light guide through TIR.

17. The illumination device of claim 1, wherein the light guide has two parallel side surfaces.

18. The illumination device of claim 1 extends orthogonally to the forward direction.

19. The illumination device of claim 18, wherein the LEEs are arranged orthogonally to the forward direction.

20. The illumination device of claim 1, wherein the LEEs are LEDs that emit white light.