Light-emitting device with total internal reflection (TIR) extractor

Patent metadata

Field	Value
Publication number	US-10151446-B2
Application number	US-201414285508-A
Country	US
Kind code	B2
Filing date	May 22, 2014
Priority date	Sep 13, 2012
Publication date	Dec 11, 2018
Grant date	Dec 11, 2018

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.

First claim

What is claimed is:

1. A light-emitting device comprising:
a plurality of light sources arranged along a path and configured to emit light during operation;
a plurality of extractor elements arranged along the path, each extractor element of the plurality of extractor elements comprising a transparent material, each of the extractor elements 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 one or more of the plurality of light sources are coupled with the light input surface of each of the extractor elements; and
a light guide coupled with the light exit surface of each extractor element of the plurality of extractor elements at a proximal end of the light guide, the light guide having (i) a light output surface at a distal end of the light guide opposite the proximal end and (ii) two side surfaces elongated along the path that extend between the proximal end and the distal end,
wherein, for each of one or more of the plurality of extractor elements,
the light input surface comprises a planar portion, and
the side surface has a first portion and a second portion, the first portion of the side surface being arranged between the planar portion of the light input surface and the second portion of the side surface, such that
the first portion of the side surface has a first shape, within at least one cross-section through the planar portion, according to R(t) being directly proportional to a product of x and Exp(t·Tan(g)),
R ( t )∝ x ·Exp( t ·Tan( g )),

where R(t) is a distance between a point P 1 of the first portion of the side surface and a point 0 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 a critical angle for total internal reflection (TIR) at the point P 1 , the first shape causing all light that is received directly from the corresponding light source on the first portion to be reflected within a first range of angles, and
the second portion of the side surface has a second shape, within the at least one cross-section, according to R(t) being directly proportional to a ratio of k to (1−cos(d−t)),

R
⁡

(
t
)

∝

k

1
-

cos
⁡

(

d
-
t

)

,

where R(t) is a distance between a point P 2 of the second portion of the side surface and the point 0 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 P 2 of a ray from the point 0 of furthest distance, wherein the first portion of the side surface terminates at an angle t c =d+2g−π and the second portion of the side surface continues for t>t c , where g is equal to or larger than the critical angle for TIR at the point P 2 , and k is a distance parameter equal to or larger than x·Exp(t c ·Tang(g))·(Cos(g)) 2 , the second shape causing all light that is received directly from the corresponding light source on the second portion to be 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 is arranged to receive and output light reflected by the side surface and light emitted by the corresponding light source into the light guide.

2. The light-emitting device of claim 1 , wherein the second portion of the side surface of each extractor element of the plurality of extractor elements extends to the light exit surface.

3. The light-emitting device of claim 1 , wherein the first portion of the side surface of each extractor element of the plurality of extractor elements extends to the light input surface.

4. The light-emitting device of claim 1 , further comprising a respective reflective layer on the first portion of the side surface of each extractor element of the plurality of extractor elements that transmits light from the light source.

5. The light-emitting device of claim 1 , further comprising a respective reflective element spaced apart from and extending along the first portion of the side surface of each extractor element of the plurality of extractor elements that transmits light from the corresponding 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.

6. The light-emitting device of claim 1 , wherein
the light exit surface of each extractor element of the plurality of extractor elements and the proximal end of the light guide forms 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.

7. The light-emitting device of claim 1 , wherein the plurality of extractor elements and the light guide are integrally formed.

8. The light-emitting device of claim 1 , wherein each light source of the plurality of light sources comprises a LED die.

9. The light-emitting device of claim 1 , wherein each light source of the plurality of light sources comprises a phosphor.

Assignees

• Quarkstar Llc

Inventors

• Speier Ingo
• Stormberg Hans Peter
• Gardner Robert C
• Magel Gregory A
• Schinagl Ferdinand
• Haitz Roland H

Classifications

• F21K9/64

  using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer · CPC title

• F21V7/0091 Primary

  using total internal reflection · CPC title

• F21V13/04

  the elements being reflectors and refractors {(for vehicle rear lights F21S43/40)} · CPC title

• F21Y2115/10

  Light-emitting diodes [LED] · CPC title

• F21V5/04

  of lens shape · CPC title