LIGHT-EMITTING DEVICE WITH TOTAL INTERNAL REFLECTION (TIR) EXTRACTOR

• US 20140334126A1
• Filed: 05/22/2014
• Published: 11/13/2014
• Est. Priority Date: 09/13/2012
• Status: Active Grant

• Current Assignee: Quarkstar LLC
• Original Assignee: Quarkstar LLC
• Inventors: Speier, Ingo, Stormberg, Hans Peter, Gardner, Robert C., Magel, Gregory A., Schinagl, Ferdinand, Haitz, Roland H.
• Granted Patent: US 10,151,446 B2
• Time in Patent Office: Days
• US Class Current: 362/84
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21V 13/04 the elements being reflectors and refractors for vehicle rear lights F21S43/40
• CPC Class Codes: F21V 13/14 the elements being filters or photoluminescent elements, reflectors and refractors
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

A variety of light-emitting devices are disclosed that are configured to output light provided by a light source. In general, embodiments of the light-emitting devices feature a light source and an extractor element coupled to the light source, where the extractor element includes, at least in part, a total internal reflection (TIR) surface. Luminaires incorporating light-emitting devices of this type are also disclosed.

Claims

1. A light-emitting device comprising:

a light source configured to emit light during operation;

an extractor element comprising a transparent material, the extractor having a light input surface, a light exit surface opposite the light input surface, and a side surface arranged between the light input surface and the light exit surface, wherein the light source is coupled with the light input surface of the extractor element; and

a light guide coupled with the light exit surface of the extractor element at a proximal end of the light guide, the light guide having a light output surface at a distal end of the light guide opposite the proximal end, wherein

at least a portion of the side surface of the extractor element is positioned and shaped such that an angle of incidence of light received from the light source that directly impinges on the at least a portion of the side surface is incident on the at least a portion of the side surface at an angle of incidence that is equal to or larger than a critical angle for total internal reflection, and

the light exit surface of the extractor element is arranged to receive and output light reflected by the side surface and light emitted by the light source into the light guide.

2. The light-emitting device of claim 1, wherein the at least a portion of the side surface of the extractor element extends to the light exit surface.

3. The light-emitting device of claim 1, wherein the at least a portion of the side surface of the extractor element extends to the light input surface.

4. The light-emitting device of claim 1, wherein the at least a portion of the side surface of the extractor element extends from the light input surface to the light exit surface.

5. The light-emitting device of claim 1, further comprising a reflective layer on a portion of the side surface of the extractor element that transmits light from the light source.

6. The light-emitting device of claim 1, further comprising a reflective element spaced apart from and extending along a portion of the side surface of the extractor element that transmits light from the light source, wherein the reflective element is configured to redirect at least a portion of light escaping through the side surface back into the extractor element.

7. The light-emitting device of claim 1, wherein

the light exit surface of the extractor element and the proximal end of the light guide form one or more optical interfaces that are positioned and shaped such that an angle of incidence of light that impinges on the one or more optical interfaces is less than respective critical angles for total internal reflection.

8. The light-emitting device of claim 1, wherein the extractor element and the light guide are integrally formed.

9. The light-emitting device of claim 1, wherein the side surface of the extractor element is shaped according to R(t)=x*Exp(t*Tan(g)), wherein

R(t) is a distance from a point of adjacency of the light input surface and the side surface to a point P on the side surface within the same sectional plane at an angle t between the input surface and a trajectory of the point of adjacency and the point P of less than 90 degrees, x is a width of the light input surface of the extractor element, and g is a critical angle for TIR, such that g=Arcsin(refractive index of an ambient environment/refractive index of the extractor element).

10. The light-emitting device of claim 1, wherein the light source comprises a LED die.

11. The light-emitting device of claim 1, wherein the light source comprises a phosphor.

12. A light-emitting device comprising:

a light source configured to emit light during operation; and

an extractor element comprising a transparent material, the extractor having a light input surface, a light exit surface opposite the light input surface, a first side surface and a second side surface opposite the first side surface, the first and second side surfaces being arranged between the light input surface and the light exit surface, wherein the light source is coupled with the light input surface, and wherein

at least a portion of the first side surface of the extractor element is positioned and shaped such that an angle of incidence of all light that is received directly from the light source on the at least a portion of the first side surface is incident at an angle of incidence that is equal to or larger than a critical angle for total internal reflection (TIR) and reflected within a first range of angles,

at least a portion of the second side surface of the extractor element is positioned and shaped such that an angle of incidence of all light that is received directly from the light source on the at least a portion of the second side surface is incident at an angle of incidence that is equal to or larger than the critical angle for TIR and reflected within a second range of angles, the second range of angles being equal to or smaller than the first range of angles, and

the light exit surface of the extractor element is arranged to receive and output light reflected by the first and second side surface, and light emitted by the light source.

13. The light-emitting device of claim 12, wherein the light exit surface is non-planar.

14. The light-emitting device of claim 13, wherein the light exit surface comprises multiple differently shaped portions.

15. The light-emitting device of claim 12, further comprising a light guide coupled with the light exit surface of the extractor element at a proximal end of the light guide, the light guide having a light output surface at a distal end of the light guide opposite the proximal end.

16. The light-emitting device of claim 12, further comprising a reflective layer on a portion of at least one of the first side surface or the second side surface.

17. The light-emitting device of claim 12, further comprising a reflective element spaced apart from and extending along a portion of at least one of the first side surface or the second side surface, wherein the reflective element is configured to redirect at least a portion of light escaping through the at least one of the first side surface or the second side surface back into the extractor element.

18. The light-emitting device of claim 12, wherein the light exit surface of the extractor element is positioned and shaped such that an angle of incidence of light that impinges on the light exit surface is less than a critical angle for total internal reflection.

19. The light-emitting device of claim 12, wherein the light input surface comprises a planar portion and the first side surface is shaped according to R(t)=x*Exp(t*Tan(g)) within at least one cross-section through the planar portion, wherein:

R(t) is a distance between a point P1 of the first side surface and a point O of furthest distance of an intersection between the planar portion and the at least one cross-section, at an angle t>

0 relative to the intersection, where x is a length of the intersection, and g is equal to or larger than the critical angle for TIR at the point P1.

20. The light-emitting device of claim 19, wherein the second side surface is shaped within the at least one cross-section according to R(t)=k/(1−

cos(d−

t)), wherein;

R(t) is a distance between a point P2 of the second side surface and the point O of furthest distance at the angle t relative to the intersection, and d is a predetermined angle defining an inclination of a ray that results from a reflection at the point P2 of a ray from the point O of furthest distance, wherein the first side surface terminates at an angle tc=d+2g−

Pi and the second side surface continues for t>

tc, where g is equal to or larger than the critical angle for TIR at the point P2, and k is equal to or larger than x*Exp(tc*Tang(g))*(Cos(g))̂

2.

21. The light-emitting device of claim 12, wherein the light source comprises a LED die.

22. The light-emitting device of claim 12, wherein the light source comprises a phosphor.