LENS WITH CONTROLLED BACKLIGHT MANAGEMENT

• US 20100302786A1
• Filed: 05/29/2009
• Published: 12/02/2010
• Est. Priority Date: 05/23/2008
• Status: Active Grant

• Current Assignee: Ruud Lighting Incorporated (Wolfspeed, Inc.)
• Original Assignee: Ruud Lighting Incorporated (Wolfspeed, Inc.)
• Inventors: Strom, Christopher, Wilcox, Kurt S.
• Granted Patent: US 8,348,475 B2
• Time in Patent Office: Days
• US Class Current: 362/327
• CPC Class Codes: F21V 13/04 the elements being reflectors and refractors for vehicle rear lights F21S43/40
• CPC Class Codes: F21V 5/008 Combination of two or more successive refractors along an optical axis
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21V 5/08 producing an asymmetric light distribution
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0061 the light source comprising a LED semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00

Abstract

A lens for distribution of light predominantly toward a preferential side from a light emitter having an emitter axis and defining an emitter plane. The lens has an emitter-adjacent base end forming an emitter-receiving opening to an emitter-surrounding cavity defined by an inner surface which includes a front sector centered on the preferential side and a back sector centered on the non-preferential side radially opposite the preferential side. The front and back sectors differ in their respective configurations for refracting light from the emitter. The lens further includes an primary back surface positioned to receive light from at least a portion of the inner-surface back sector and configured for total internal reflection (TIR) thereof. The inner-surface back sector and the primary back surface extend along substantially elliptical cross-sections in planes substantially parallel to the emitter plane. The emitter-adjacent base end forms a back opening to a back cavity substantially centered on the non-preferential side and partially bounded by the primary back surface.

Claims

1. A lens for distribution of light predominantly toward a preferential side from a light emitter having an emitter axis and defining an emitter plane, comprising:

an emitter-adjacent base end forming an emitter-receiving opening to an emitter-surrounding cavity defined by an inner surface including (a) a front sector centered on the preferential side and having a first configuration for refracting light from the emitter and (b) a back sector centered on the non-preferential side radially opposite the preferential side and having a second configuration for refracting light from the emitter, the second configuration differing from the first configuration; and

an axially-offset primary back surface positioned to receive light from at least a portion of the inner-surface back sector and configured for total internal reflection (TIR) thereof.

2. The lens of claim 1 wherein light from the primary back surface is directed toward the preferential side.

3. The lens of claim 1 wherein the inner-surface back sector and the primary back surface having substantially elliptical cross-sections in planes substantially parallel to the emitter plane.

4. The lens of claim 3 wherein such substantially-elliptical cross-sections are elliptical wide sides.

5. The lens of claim 1 wherein the emitter-adjacent base end forms a back opening to a back cavity substantially centered on the non-preferential side and partially bounded by the primary back surface.

6. The lens of claim 5 wherein the primary back surface transitions from near the inner-surface back sector at the emitter plane away from the emitter axis to terminate at a position distal from the base end.

7. The lens of claim 6 wherein the back cavity is further bounded by an axially-remote secondary back surface and an end surface extending from the primary back surface to the secondary back surface, the secondary back surface extending from the end surface to the base end and having substantially elliptical cross-sections in planes parallel to the emitter plane.

8. The lens of claim 1 wherein the inner-surface back sector includes an intermediate back zone configured for refracting emitter light predominantly toward the primary back surface for TIR thereof toward the preferential side.

9. The lens of claim 8 wherein the inner-surface back sector further includes an axially-adjacent back zone which is configured for refracting emitter light away from the emitter plane and joins the intermediate back zone by transitioning from the emitter axis away from the emitter plane.

10. The lens of claim 9 wherein the axially-adjacent back zone is substantially cross-sectionally convex.

11. The lens of claim 9 wherein the intermediate back zone includes a first intermediate back section extending away from the emitter axis.

12. The lens of claim 11 wherein the intermediate back zone further includes:

a second intermediate back section which extends from the first intermediate back section to the axially-adjacent back zone; and

a third intermediate back section transitioning from the first intermediate back section toward the emitter plane and configured for refracting emitter light toward the emitter plane with progressively lesser refraction at positions progressively closer to the emitter plane.

13. The lens of claim 12 wherein the second and third intermediate back sections extend substantially orthogonally to the emitter plane and having substantially elliptical cross-sections in planes parallel to the emitter plane.

14. The lens of claim 1 further including an outer surface configured for refracting emitter light in predominantly off-axis directions toward the preferential side.

15. The lens of claim 14 wherein the outer surface has front and back output regions, the back output region being configured for refracting a preponderance of light received from the inner-surface back sector and the primary back surface toward the preferential side.

16. The lens of claim 15 wherein the inner-surface front sector includes:

a first front region adjacent to the emitter axis and configured for refracting emitter light toward the emitter plane;

a second front region spaced from the first front region and configured for refracting emitter light away from the emitter plane; and

a middle front region joining and substantially cross-sectionally asymptotical to the first and second front regions, the middle front region being positioned with respect to the emitter to refract light toward the emitter plane by progressively lesser amounts at positions progressively closer to the second front region.

17. The lens of claim 16 wherein the front output region of the outer surface is configured for refracting light from the inner-surface front sector such that at the outer surface light from each front region is refracted substantially without overlapping light from other front regions.

18. The lens of claim 17 wherein:

the second front region terminates before reaching the emitter plane; and

the inner-surface front sector further includes a base-adjacent front region extending from the second front region and configured such that the light emitted between the second front region and the emitter plane passes through the base-adjacent front region substantially free of refraction.

19. The lens of claim 18 further includes a peripheral front surface positioned to receive light from the base-adjacent front region and configured for total internal reflection (TIR) thereof toward the outer surface.

20. The lens of claim 19 wherein the emitter-adjacent base end forms a front opening to a front cavity centered on the preferential side and partially bounded by the peripheral front surface.

21. The lens of claim 1 wherein the front sector extends about the emitter axis along an arc that is greater than the arc along which the back sector extends.

22. The lens of claim 21 wherein the back-sector arc is about half the front-sector arc.

23. The lens of claim 1 being substantially bilaterally symmetrical about a plane including the emitter axis.

24. A lens for distribution of light predominantly toward a preferential side from a light emitter having an emitter axis and defining an emitter plane, comprising an emitter-adjacent base end forming:

an emitter-receiving opening to an emitter-surrounding cavity defined by an inner surface which is configured for refracting light from the emitter and includes (a) a front sector centered on the preferential side and (b) a back sector centered on the non-preferential side radially opposite the preferential side; and

a back opening to a back cavity partially bounded by a primary back surface positioned to receive light from at least a portion of the inner-surface back sector and configured for total internal reflection (TIR) thereof.

25. The lens of claim 24 wherein the emitter-adjacent base end forms a front opening to a front cavity partially bound by a peripheral front surface positioned to receive light from a base-adjacent region of the inner-surface front sector and configured for total internal reflection (TIR) thereof toward the lens outer-surface.

26. A lens for distribution of light predominantly toward a preferential side from a light emitter having an emitter axis and defining an emitter plane, comprising:

an emitter-adjacent base end forming an emitter-receiving opening to an emitter-surrounding cavity defined by an inner surface which is configured for refracting light from the emitter and includes (a) a front sector centered on the preferential side and (b) a back sector centered on the non-preferential side radially opposite the preferential side and having substantially elliptical cross-sections in planes substantially parallel to the emitter plane; and

a primary back surface positioned to receive light from at least a portion of the inner-surface back sector and configured for total internal reflection (TIR) thereof, the primary back surface having substantially elliptical cross-sections in planes substantially parallel to the emitter plane.