# US 8,541,795 B2 · Side-emitting optical coupling device

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- Number: US 8,541,795 B2
- Document ID: US8541795B2
- Status: Granted
- Kind: B2
- Application number: 11/247,563
- Filed: 2005-10-10
- Published: 2006-04-13
- Granted: 2013-09-24
- Earliest claimed: 2004-10-12
- Assignees: Cree, Inc.
- Applicants: Bernd Keller; Benjamin Jacobson; Robert Gengelbach
- Inventors: Bernd Keller; Benjamin Jacobson; Robert Gengelbach
- Web page: https://patentgrep.com/patent/US8541795B2

## CPC

- H10H 20/855: Optical field-shaping means, e.g. lenses
- F21K 9/60: Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
- F21K 9/61: using light guides
- G02B 6/4214: {the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device (G02B6/4246 takes precedence)}
- G02B 19/0028: {refractive and reflective surfaces, e.g. non-imaging catadioptric systems}
- G02B 19/0061: {the light source comprising a LED}
- G02B 19/0071: {adapted to illuminate a complete hemisphere or a plane extending 360 degrees around the source}
- H10H 20/8506: {Containers}
- H10H 20/852: Encapsulations
- F21Y 2115/10: Light-emitting diodes [LED]
- H10H 20/853: characterised by their shape
- H10H 20/856: Reflecting means
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- F21K: NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- F21Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED

## Abstract

An LED package includes a LED structure that outputs light in a pattern about an axis and an optical coupling device with a central axis. The coupling device is positioned relative to the LED structure and accepts light from the LED. The coupling device includes a first dielectric interface surface that is substantially cylindrical with respect to the central axis, and a reflecting surface. The first dielectric interface surface accepts a first portion of light from the LED structure and directs it toward the reflecting surface. The reflecting surface accepts the light from the first dielectric interface surface and directs it toward the first dielectric interface surface in a direction substantially perpendicular to the central axis.

## Claims

### Claim 1

A light emitting diode (LED) package comprising:
an LED structure outputting light in a pattern about an axis; and
an optical coupling device having a central axis and positioned relative to the LED structure to accept light from the LED, the device comprising a homogenous first dielectric interface surface that is substantially cylindrical with respect to the central axis, and a multi-faceted reflecting surface comprising a plurality of faces, each of the faces arranged to reflect light in a direction substantially perpendicular to the central axis, the first dielectric interface surface accepting a first portion of substantially unrefracted light from the LED structure and directing it toward the reflecting surface, the reflecting surface accepting the light from the first dielectric interface surface and directing it toward the first dielectric interface surface to exit the device in a direction substantially perpendicular to the central axis;
wherein said reflecting surface extends to cover the entire surface of revolution about the central axis;
wherein a first face is obliquely angled with respect to the central axis from a side closest to the LED structure that accepts the first portion of light from the first dielectric interface surface;
wherein a second face is obliquely angled with respect to the central axis from a side closest to the LED structure that accepts another portion of light from the LED structure and directs it toward the first dielectric interface surface in a direction substantially perpendicular to the central axis, wherein at least one of said first and second faces is straight; and
wherein a third face of the reflecting surface extends outward and beyond the first dielectric interface surface.

### Claim 2 (depends on 1)

The LED package of claim 1 wherein the optical coupling device further comprises a second dielectric interface surface accepting a second portion of light from the LED structure and refracting it from the device in a direction substantially perpendicular to the central axis.

### Claim 3 (depends on 2)

The LED package of claim 2 wherein the second dielectric interface surface is convex.

### Claim 4 (depends on 1)

The LED package of claim 1 wherein the reflecting surface extends into the cylinder defined by the first dielectric interface surface.

### Claim 5 (depends on 1)

The LED package of claim 1 wherein a plurality of the faces of the reflecting surface are concave.

### Claim 6 (depends on 1)

The LED package of claim 1 wherein the first face of the reflecting surface is substantially linear.

### Claim 7 (depends on 1)

The LED package of claim 1 wherein the second face of the reflecting surface is substantially linear.

### Claim 8 (depends on 1)

The LED package of claim 1 wherein the first face of the reflecting surface is convex.

### Claim 9 (depends on 1)

The LED package of claim 1 wherein the second face of the reflecting surface is convex.

### Claim 10 (depends on 1)

The LED package of claim 1 wherein the second face is obliquely angled with respect to the central axis at an angle different than the first face.

### Claim 11 (depends on 1)

The LED package of claim 1 wherein said third face accepts a portion of light refracted by the first dielectric interface surface and directs it away from the central axis and in a direction substantially perpendicular to the central axis.

### Claim 12 (depends on 11)

The LED package of claim 11 wherein the third face of the reflecting surface is substantially linear.

### Claim 13 (depends on 11)

The LED package of claim 11 wherein the third face is obliquely angled with respect to the central axis from a side closest to the LED structure at an angle different than either of the first face or the second face of the reflecting surface.

### Claim 14 (depends on 11)

The LED package of claim 11 wherein the third face is substantially perpendicular with respect to the central axis of the reflecting surface.

### Claim 15 (depends on 11)

The LED package of claim 11 wherein the third face of the reflecting surface is concave.

### Claim 16 (depends on 1)

The LED package of claim 1 wherein the LED structure includes a base structure and an LED on the base structure, and the optical coupling device is positioned over the LED and the base structure.

### Claim 17 (depends on 16)

The LED package of claim 16 wherein the optical coupling device is in direct contact with the LED.

### Claim 18 (depends on 16)

The LED package of claim 16 wherein a volume exists between the LED and the optical coupling device.

### Claim 19 (depends on 18)

The LED package of claim 18 wherein the volume is filled with a material having an index of refraction substantially the same as the optical coupling device.

### Claim 20 (depends on 18)

The LED package of claim 18 wherein the volume is filled with air.

### Claim 21

A lens for use with a light emitting device that outputs light in a pattern about an axis, said lens comprising:
a first dielectric interface surface that is substantially cylindrical with respect to a central axis; and
a reflecting surface comprising an inward-extending portion that extends into the cylinder defined by the first dielectric interface surface, wherein said reflecting surface extends to cover the entire surface of revolution about the central axis, wherein the first dielectric interface surface directs light toward the reflecting surface;
wherein the reflecting surface contains at least first and second faces, each of said faces arranged to reflect light toward the first dielectric interface surface, that are obliquely angled with respect to the central axis; and
wherein the reflecting surface comprises a third concave face arranged to reflect light away from the first dielectric interface surface, and an outward-extending portion coupled to said inward-extending portion to form a continuous reflective body, wherein said outward-extending portion extends outward with respect to the first dielectric interface surface.

### Claim 22 (depends on 21)

The lens of claim 21 further comprising a second dielectric interface surface beneath the first dielectric interface surface that extends outward from the first dielectric interface surface.

### Claim 23 (depends on 22)

The lens of claim 22 wherein the second dielectric interface surface is convex.

### Claim 24 (depends on 21)

The lens of claim 21 wherein the inward-extending portion of the reflecting surface is formed as part of a structure that includes the first dielectric interface surface.

### Claim 25 (depends on 21)

The lens of claim 21 wherein the inward-extending portion of the reflecting surface is affixed to a structure that includes the first dielectric interface surface.

### Claim 26 (depends on 21)

The lens of claim 21 wherein the outward-extending portion of the reflecting surface is affixed to the inward-extending portion of the reflecting surface.

### Claim 27 (depends on 21)

The lens of claim 21 wherein the inward-extending and outward-extending portions of the reflecting surface are affixed to a structure that includes the first dielectric interface surface.

### Claim 28 (depends on 27)

The lens of claim 27 wherein the reflecting surface comprises a cup structure comprising a reflective lower surface.

### Claim 29 (depends on 21)

The lens of claim 21 wherein the inward-extending and outward-extending portions of the reflecting surface and a structure that includes the first dielectric interface surface comprise one piece.

### Claim 30 (depends on 21)

The lens of claim 21 wherein said outward-extending portion extends past the remaining structure.

### Claim 31

A lens for use with a light emitting device that outputs light in a pattern about an axis, said lens comprising:
a first dielectric interface surface that is substantially cylindrical with respect to a central axis; and
a reflecting surface comprising an inward-extending portion that extends into and is received by a recess of the cylinder defined by the first dielectric interface surface, wherein said inward-extending portion contains at least first and second faces that are obliquely angled with respect to the central axis, each of said faces arranged to reflect light toward the first dielectric interface surface;
wherein the reflecting surface further comprises an outward-extending portion that extends outward with respect to the first dielectric interface surface;
wherein the outward-extending portion extends past the remaining structure;
wherein the outward-extending portion of the reflecting surface is formed separate from the inward-extending portion of the reflecting surface and configured to expose said recess;
wherein the outward-extending portion is a ring structure comprising a reflective lower surface.

### Claim 32 (depends on 31)

The lens of claim 31, wherein said ring structure is placed over said inward-extending portion.

### Claim 33

A method of directing light from a light emitting device, said method comprising:
generating light output from the light emitting device in a pattern about an axis; and
redirecting the light output using an optical coupling device having a central axis and positioned relative to the LED structure to accept light from the LED, the device comprising a homogenous first dielectric interface surface that is substantially cylindrical with respect to the central axis, and a reflecting surface comprising at least first, second and third faces configured to form a continuous reflective body, each of the first and second faces arranged to reflect light toward said first dielectric interface surface in a direction substantially perpendicular to the central axis, wherein the third face extends outward with respect to said first dielectric interface surface and is arranged to reflect light away from said first dielectric interface surface in a direction substantially perpendicular to the central axis, said first and second faces are obliquely angled with respect to the central axis from a side closest to the LED, at least one of said faces is linear, and said third face is concave, wherein redirecting light comprises:
accepting a first portion of substantially unrefracted light from the LED structure at the first dielectric interface surface and directing it toward the reflecting surface;
accepting the light from the first dielectric interface surface at the reflecting surface and directing it toward the first dielectric interface surface in a direction substantially perpendicular to the central axis; and
accepting a second portion light directly from the LED structure at the reflecting surface and directing it toward the first dielectric interface surface in a direction substantially perpendicular to the central axis.

### Claim 34 (depends on 33)

The method of claim 33 wherein the method further comprises:
accepting a portion of light redirected by either the first dielectric interface surface or the reflecting surface; and
directing it away from the central axis and in a direction substantially perpendicular to the central axis.