# US 8,465,180 B2 · Optical element for asymmetric light distribution

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- Number: US 8,465,180 B2
- Document ID: US8465180B2
- Status: Granted
- Kind: B2
- Application number: 12/992,102
- Filed: 2009-05-13
- Published: 2011-04-07
- Granted: 2013-06-18
- Earliest claimed: 2008-05-20
- Assignees: Koninklijke Philips N.V.
- Applicants: Denis Joseph Carel Van Oers; Rob Franciscus Maria Van Elmpt
- Inventors: Denis Joseph Carel Van Oers; Rob Franciscus Maria Van Elmpt
- Web page: https://patentgrep.com/patent/US8465180B2

## CPC

- F21V 5/04: of lens shape
- A01G 9/249: {Lighting means (with special arrangements for promoting growth A01G7/045)}
- F21V 5/08: producing an asymmetric light distribution
- F21V 7/0091: {using total internal reflection}
- G02B 19/0028: {refractive and reflective surfaces, e.g. non-imaging catadioptric systems}
- G02B 19/0061: {the light source comprising a LED}
- G02B 27/095: {Refractive optical elements}
- G02B 27/0983: {being curved}
- F21Y 2115/10: Light-emitting diodes [LED]
- Y02A 40/25: Greenhouse technology, e.g. cooling systems therefor
- F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- A01G: HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING (picking of fruits, vegetables, hops or the like A01D46/00; propagating unicellular algae C12N1/12)
- 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
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE

## Abstract

The present invention relates to an optical element (2) for collimating light from a light source (3), said optical element (2) having an in-coupling side (5) arranged to receive said light, an out-coupling side (6) arranged to allow for emission of collimated light, and an element body extending from said in-coupling side (5) to said out-coupling side (6), the element body having a cross-section perpendicular to an optical axis (z) defined by an x-5 axis and a y-axis being perpendicular to each other, wherein said optical element (2) has an x-curvature along said x-axis and a y-curvature along said y-axis, said y-curvature being greater than said x-curvature, thereby enabling for a light distribution of said collimated light emitted from said out-coupling side (6) to have a cross-section of an asymmetric shape (CE) perpendicular to said optical axis (z). The present invention also relates to a lighting system (1) comprising such an optical element (2). An advantage with the present invention is that it may provide asymmetric light distribution with an increased beam-width difference in two perpendicular viewing directions.

## Claims

### Claim 1

Optical element for collimating light from a light source, said optical element having an in-coupling side arranged to receive said light and an out-coupling side arranged to allow for emission of collimated light, said optical element comprising
a substantially transparent or translucent element body extending from said in-coupling side to said out-coupling side, the element body having a cross-section perpendicular to an optical axis (z) defined by an x-axis and a y-axis being perpendicular to each other,
wherein said element body has an x-curvature along said x-axis and a y-curvature along said y-axis, said y-curvature being greater than said x-curvature, thereby enabling for a light distribution of said collimated light emitted from said out-coupling side to have a cross-section of an asymmetric shape (CE) perpendicular to said optical axis (z),
wherein a refractive index of the element body is higher than a medium surrounding it and the x- and y-curvatures are selected to achieve a total internal reflection (TIR).

### Claim 2 (depends on 1)

Optical element according to claim 1, wherein a light distribution of said collimated light emitted from said out-coupling side has a cross-section of an elliptic shape (CE) perpendicular to said optical axis (z).

### Claim 3 (depends on 1)

Optical element according to claim 1, wherein said elliptic shape (CE) has a greater width along said x-axis than along said y-axis.

### Claim 4 (depends on 1)

Optical element according to claim 1, wherein said x- and y-curvatures in relation to each other are defined such that a maximum diverging angle (θx) of said light beams along said x-axis, is at least 15 degrees greater than a corresponding maximum diverging angle (θy) along said y-axis.

### Claim 5 (depends on 1)

Optical element according to claim 1, wherein said optical element comprises poly carbonate and/or polymethylmetacrylate.

### Claim 6 (depends on 1)

Optical element according to claim 1, wherein said out-coupling side is substantially flat.

### Claim 7 (depends on 1)

Optical element according to claim 1, wherein said out-coupling side comprises a lens structure.

### Claim 8 (depends on 1)

A lighting system comprising an optical element according to claim 1 and a light source, wherein said in-coupling side of the optical element is adapted to receive light emitted by the light source.

### Claim 9 (depends on 8)

The lighting system according to claim 8, wherein said light source comprises at least one light emitting diode (LED).