Light source for uniform illumination of a surface

• US 10,072,819 B2
• Filed: 10/02/2015
• Issued: 09/11/2018
• Est. Priority Date: 10/02/2014
• Status: Active Grant

• Current Assignee: LEDVANCE LLC (MLS Co. Ltd.)
• Original Assignee: LEDVANCE LLC (MLS Co. Ltd.)
• Inventors: Catalano, Anthony W.
• Primary Examiner(s): Dzierzynski, Evan
• Assistant Examiner(s): Delahoussaye, Keith G
• Application Number:
  US14/874,128
• Publication Number:
  US 20160097511A1
• Time in Patent Office: 1,075 Days
• Field of Search: 36221705-21707, 362233, 362297, 362307, 362346, 362347
• CPC Class Codes: F21S 8/04 intended only for mounting on a ceiling or the like overhead structures F21S8/02 takes precedence; details of ceiling bases F21V21/03
• CPC Class Codes: F21V 7/0016 on lighting devices that also provide for direct lighting, e.g. by means of independent light sources, by splitting of the light beam, by switching between both lighting modes
• CPC Class Codes: F21V 7/005 with an elongated shape to cooperate with linear light sources
• CPC Class Codes: F21V 7/048 with facets structure
• CPC Class Codes: F21V 7/08 with elliptical curvature
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

Devices and methods for uniform illumination of a target surface are disclosed. A device assembly has a light source configured to be coupled to a mounting surface, and at least one reflector. The reflector is configured to be coupled to at least one of the light source or the mounting surface, and interposed between the light source and the mounting surface, the reflector having a reflective surface area and a plurality of curved reflective segments. The reflector is shaped and arranged relative to the light source such that the reflector directly intercepts and reflects a portion of light emitted by the light source to the target surface to thereby cause substantially uniform illumination of the target surface. The target surface has a surface area that is greater than the reflective surface area of the at least one reflector.

Claims

1. A device configured for uniform illumination of a target surface, the device comprising:

an elongated light emitting diode (LED) light source extending along or substantially along an x axis and having an irregular light distribution; and

two or more reflectors having a length relative to the x axis and a reflective surface area, the two or more reflectors meeting nontangentially, wherein the elongated LED light source is arranged between the two or more reflectors, the reflective surface area comprising a profile having a plurality of curved reflective segments meeting nontangentially;

wherein

the target surface has a target surface area that is greater than the reflective surface area;

the target surface has a first region and a second region, the first region comprising an intersection between the target surface and a normal of the elongated LED light source, the second region being further from the intersection than the first region is;

a first of the curved reflective segments is configured to reflect light primarily to the second region of the target surface;

a second of the curved reflective segments is configured to reflect light primarily to the first region of the target surface;

the elongated LED light source and the at least one reflector are arranged such that the at least one reflector is configured to directly intercept and reflect a portion of light emitted by the elongated LED light source to thereby cause substantially uniform illumination of the target surface;

at least some of the light reflected by the first curved reflective segment, and the light reflected by the second curved reflective segment cross paths; and

wherein the elongated LED light source is non-linear in a direction that is perpendicular to a plane that is parallel to a radial axis of the elongated light source.

2. The device of claim 1, wherein the plurality of curved reflective segments are elliptical, and therefore have two foci, one of each of these foci having a common focus coincident with the elongated LED light source, and a second of each of these foci being non-coincident with each other and distributed over the target surface.

3. The device of claim 2, wherein the second foci of the plurality of elliptical segments are substantially evenly distributed over the target surface.

4. The device of claim 1, wherein:

the first curved reflective segment is configured to receive light having a first intensity from the elongated LED light source, and reflect the light having the first intensity to a first spatial region, the first spatial region has a first distance from the elongated LED light source;

and wherein the second elliptical segment is configured to receive light having a second intensity from the elongated LED light source and reflect the light having the second intensity to a second spatial region, the second spatial region has a second distance from the elongated LED light source, the second distance less than the first distance, and the second intensity being lower than the first intensity.

5. The device of claim 1, wherein:

the first curved reflective segment has a first reflective area; and

the second curved reflective segment has a second reflective area, the first reflective area is less than the second reflective area, and wherein the first curved reflective segment is closer to the elongated LED light source than the second curved reflective segment.

6. The device of claim 1, wherein the at least one reflector subtends an angle of approximately 45°

, measured from a center of the elongated LED light source.

7. The device of claim 1, wherein the at least one reflector subtends an angle of approximately 90°

, measured from a center of the elongated LED light source.

8. The device of claim 1, wherein the device further comprises an optical element placed between the two reflectors.

9. The device of claim 1, wherein the plurality of curved reflective segments have a common focus coincident with the elongated LED light source.

10. The device of claim 9, wherein directing angles of the parabolic segments or elliptical segments are evenly distributed over the target surface.

11. The device of claim 1, wherein a first and second of the two or more reflectors are not identical to each other.

12. The device of claim 1, further comprising an actuator to adjust a position of at least one curved reflective segment.

13. A device assembly configured for uniform illumination of a target surface, the device assembly comprising:

a light emitting diode (LED) light source configured to be coupled to a mounting surface; and

two or more reflectors meeting nontangentially and configured to be coupled to at least one of the LED light source or the mounting surface, and interposed between the LED light source and the mounting surface, the two or more reflectors each having a reflective surface area, the two or more reflectors comprising a plurality of curved reflective segments meeting nontangentially, wherein the LED light source is arranged between the two or more reflectors;

wherein the two or more reflectors are shaped and arranged relative to the LED light source such that the two or more reflectors intercept and reflect a portion of light emitted by the LED light source to the target surface to thereby cause substantially uniform illumination of the target surface;

wherein the target surface has a surface area that is greater than the reflective surface area of the two or more reflectors; and

wherein the elongated LED light source is non-linear in a direction that is perpendicular to a plane that is parallel to a radial axis of the elongated light source.

14. The device assembly of claim 13, wherein the two or more reflectors comprise a first elliptical segment and a second elliptical segment;

wherein the first elliptical segment is configured to receive light having a first intensity from the LED light source and reflect the light having the first intensity to a first spatial region of the target surface, the first spatial region a first distance from the LED light source;

and wherein the second elliptical segment is configured to receive light having a second intensity from the LED light source and reflect the light having the second intensity to a second spatial region of the target surface, the second spatial region a second distance from the LED light source, the second distance less than the first distance, and the second intensity being lower than the first intensity.

15. The device assembly of claim 13;

wherein

the surface area of the target surface is at least ten times greater than the reflective surface area.

16. The device assembly of claim 13;

wherein

a first one of the plurality of reflective segments is configured to receive light having a first intensity from the LED light source;

a second one of the plurality of reflective segments is configured to receive light having a second intensity from the LED light source, the second intensity less than the first intensity;

the first one of the plurality of reflective segments is configured to transform the light having the first intensity into a reflected light having a third intensity; and

the second one of the plurality of reflective segments is configured to transform the light having the second intensity into a reflected light having the third intensity.

17. A method for uniform illumination of a target surface, comprising:

emitting light by an elongated light emitting diode (LED) light source, the elongated light source extending along an x axis and having an irregular light distribution; and

causing two or more reflectors extending parallel to at least a portion of the elongated LED light source, and meeting nontangentially, and having a plurality of curved reflective segments meeting nontangentially to directly intercept and reflect a portion of light emitted by the elongated LED light source, wherein the elongated LED light source is arranged between the two or more reflectors, the two or more reflectors having a reflective surface area;

causing a first curved reflective segment to reflect light to a second region of the target surface;

causing a second curved reflective segment to reflect light to a first region of the target surface;

causing the light reflected by the first curved reflective segment and the light reflected by the second curved reflective segment to cross paths;

effecting substantially uniform illumination of the target surface, the target surface having an area greater than the reflective surface area of the at least one reflector; and

wherein the elongated LED light source is non-linear in a direction that is perpendicular to a plane that is parallel to a radial axis of the elongated light source.

18. The method of claim 17, wherein the at least one reflector comprises a plurality of elliptical segments having a common focus coincident with the elongated LED light source and different second foci distributed over the target surface.

19. The method of claim 17, wherein the target surface is irregular, and the two or more reflectors and the plurality of curved reflective segments are shaped to substantially uniformly illuminate the irregular target surface.