Uniform light source with variable beam divergence

• US 10,352,532 B2
• Filed: 12/17/2015
• Issued: 07/16/2019
• Est. Priority Date: 12/17/2014
• Status: Active Grant

• Current Assignee: LEDVANCE LLC (MLS Co. Ltd.)
• Original Assignee: LEDVANCE LLC (MLS Co. Ltd.)
• Inventors: Catalano, Anthony W.
• Primary Examiner(s): Coughlin, Andrew J
• Application Number:
  US14/973,532
• Publication Number:
  US 20160178142A1
• Time in Patent Office: 1,307 Days
• Field of Search: 36229605
• CPC Class Codes: F21V 14/02 by movement of light sources in vehicle head lamps F21S41/657
• CPC Class Codes: F21V 14/04 by movement of reflectors in vehicle head lamps F21S41/675
• CPC Class Codes: F21V 7/06 with parabolic curvature
• CPC Class Codes: F21V 7/08 with elliptical curvature
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

A light source producing a beam of variable divergence, comprising one or more light-emitting devices arranged on a planar substrate, with each of the light-emitting devices having a Lambertian emission distribution. The light source may further comprise a chamber for mixing light emitted from the one or more light-emitting devices, the chamber itself comprising a base defined by the planar substrate, one or more side walls having a reflective interior surface, and a planar diffusive emission surface defining a ceiling of the chamber. The chamber may have an adjustable height. A reflector extends from the chamber for redirecting light exiting from the chamber to form a light beam, the reflector surrounding and having a focal plane coincident with the ceiling of the chamber. Finally, the light source may comprise a mechanism to control a height of the chamber to thereby variably control a divergence of the light beam.

Claims

1. A light source producing a beam of variable divergence, the light source comprising:

one or more light-emitting devices arranged on a planar substrate, each of the light-emitting devices having a Lambertian emission distribution;

a chamber for mixing light emitted from the one or more light-emitting devices, the chamber comprising a base defined by the planar substrate, one or more side walls having a reflective interior surface, and a planar diffusive emission surface defining a ceiling of the chamber, the chamber having an adjustable height;

a reflector extending from the chamber for redirecting light exiting from the chamber to form a light beam, the reflector surrounding and having a focal plane coincident with the ceiling of the chamber, wherein the one or more side walls are flexible; and

a mechanism to control a height of the chamber to thereby variably control a divergence of the light beam.

2. The light source of claim 1, wherein the one or more light-emitting devices are arranged in a pattern having a diameter, a ratio of the height of the chamber to the diameter of the pattern being no greater than five-to-one.

3. The light source of claim 1, wherein the one or more light-emitting devices are arranged in a pattern having a diameter and the base has a diameter, a ratio of the diameter of the base to the diameter of the pattern being at least five-to-one.

4. The light source of claim 1, wherein a ratio of the height of the chamber to a radius of the planar diffusive emission surface is no greater than two-to-one.

5. The light source of claim 1, wherein the reflector is parabolic or elliptic.

6. The light source of claim 1, wherein the reflector comprises a series of concentric, identically shaped sections having a collimated output at an exit aperture of the reflector and an off-axis aiming angle at the focal plane.

7. The light source of claim 6, wherein the off-axis aiming angle is approximately 25°

.

8. The light source of claim 1, wherein the interior surface of the one or more side walls is diffusely reflective.

9. The light source of claim 1, wherein the interior surface of the one or more side walls is specularly reflective.

10. The light source of claim 1, wherein the one or more side walls comprises one or more pleats forming a bellows.

11. The light source of claim 1, wherein the mixing chamber has a frusto-conical profile when the mixing chamber is at a maximum height.

12. The light source of claim 1, wherein the mechanism to control the height of the chamber is mechanical.

13. The light source of claim 1, wherein the apparatus configured to control the height of the chamber is electromechanical.

14. The light source of claim 1, wherein the apparatus configured to control the height of the chamber comprises a memory for storing a quantitative relationship between beam divergence and chamber height, a user interface for receiving a user-supplied beam divergence value, and circuitry for adjusting the chamber height to produce the user-supplied beam divergence value.

15. The light source of claim 1, wherein the apparatus configured to control the height of the chamber comprises a memory for storing a quantitative relationship between center beam intensity and chamber height, a user interface for receiving a user-supplied center beam intensity value, and circuitry for adjusting the chamber height to produce the user-supplied center beam intensity value.

16. A light source, comprising:

one or more light-emitting devices arranged on a planar substrate;

a chamber for mixing light emitted from the one or more light-emitting devices, the chamber comprising a base defined by the planar substrate, one or more side walls having a reflective interior surface, and a planar diffusive emission surface defining a ceiling of the chamber, wherein the base is movable in relation to the ceiling, wherein the one or more side walls are flexible;

a reflector extending from the chamber for redirecting light exiting from the chamber to form a light beam, the reflector surrounding and having a focal plane coincident with the ceiling of the chamber.

17. An adjustable light source for producing a light beam of variable divergence, the light source comprising:

one or more light-emitting devices arranged on a reflective substrate,

a chamber for mixing light emitted from the one or more light-emitting devices, the chamber comprising a base defined by the reflective substrate, one or more side walls having a reflective and flexible interior surface, and a diffusive emission surface defining a ceiling of the chamber, wherein the distance between the base and the ceiling is adjustable,

a reflector extending from the chamber for redirecting light exiting from the chamber to form a light beam, the reflector surrounding and having a focus coincident with the ceiling of the chamber; and

a mechanism for adjusting the distance between the base and the ceiling, wherein adjusting the distance changes the divergence of the light beam.