Method and System for Managing Light from a Light Emitting Diode

• US 20120300488A1
• Filed: 02/28/2012
• Published: 11/29/2012
• Est. Priority Date: 02/28/2011
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Cooper Technologies Company (Eaton Corporation PLC.)
• Inventors: Broughton, Kevin Charles
• Granted Patent: US 9,052,086 B2
• Time in Patent Office: Days
• US Class Current: 362/555
• CPC Class Codes: F21S 8/032 the surface being a floor or like ground surface, e.g. pavement
• CPC Class Codes: F21V 13/04 the elements being reflectors and refractors for vehicle rear lights F21S43/40
• CPC Class Codes: F21V 15/01 Housings, e.g. material or assembling of housing parts F21V15/02 takes precedence housings forming signs or letters G09F13/04
• CPC Class Codes: F21V 3/02 characterised by the shape
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21V 5/08 producing an asymmetric light distribution
• CPC Class Codes: F21V 7/0066 specially adapted to cooperate with point like light sources; specially adapted to cooperate with light sources the shape of which is unspecified F21V7/16 - F21V7/30 take precedence
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21V 7/28 characterised by coatings
• CPC Class Codes: F21W 2131/103 of streets or roads
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 17/086 wherein the system is made of a single block of optical material, e.g. solid catadioptric systems
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0061 the light source comprising a LED semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02B 5/124 plural reflecting elements forming part of a unitary plate or sheet
• CPC Class Codes: G02B 5/13 plural curved refracting elements forming part of a unitary body

Abstract

A light source, for example a light emitting diode, can emit light and have an associated optical axis. The source can be deployed in applications where it is desirable to have illumination biased laterally relative to the optical axis, such as in a street luminaire where directing light towards a street is beneficial. The source can be coupled to an optic that comprises an inner surface facing the source and an outer surface that is opposite the inner surface. The inner surface can comprise a refractive surface that receives light headed away from the optical axis of the light source, for example opposite the street. The refractive surface can form the received light into a beam. The outer surface of the optic can reflect the beam back across the optical axis, for example so that light headed away from the street is redirected towards the street.

Claims

1. A method comprising:

emitting light from a light source having a first optical axis, a section of the emitted light headed towards a first feature on a first side of a unitary optical element, the first side facing the light source;

responsive to incidence on the first feature, refracting the section of the emitted light to form a beam having a second optical axis, the beam headed towards a second feature on a second side of the unitary optical element, wherein the second side is opposite the first side, and wherein the second optical axis is angled relative to the first optical axis;

responsive to incidence of the beam on the second feature, totally internally reflecting the beam; and

transmitting the totally internally reflected beam out of the unitary optical element.

2. The method of claim 1,

wherein the light source comprises a light emitting diode,

wherein the second optical axis is disposed at an acute angle relative to the first optical axis,

wherein the first side of the unitary optical element forms a cavity in which at least a dome of the light emitting diode is disposed,

wherein the first feature comprises a convex surface bulging into the cavity,

wherein transmitting the totally internally reflected beam out of the unitary optical element comprises the totally internally reflected beam exiting the unitary optical element through a concave surface that diverges the beam.

3. The method of claim 1, wherein the unitary optical element is formed from a plurality of transparent plastic elements bonded together.

4. The method of claim 1, wherein the unitary optical element comprises molded plastic that is transparent, and

wherein the first feature is concave.

5. An illumination system comprising:

an optic comprising a first surface that defines a cavity and a second surface opposite the first surface; and

a light emitting diode disposed at least partially in the cavity, the light emitting diode having a first optical axis,

wherein the first surface comprises a refractive contour having a second optical axis,

wherein the first optical axis and the second optical axis form an acute angle, and

wherein the second surface comprises a totally internally reflective feature.

6. The illumination system of claim 5, wherein the refractive contour bulges towards the light emitting diode and away from the second surface.

7. The illumination system of claim 5, wherein the totally internally reflective feature juts out from the second surface and away from the light emitting diode.

8. The illumination system of claim 5, wherein the second surface further comprises a refractive feature oriented to receive and refract light from the totally internally reflective feature.

9. The illumination system of claim 5, wherein the refractive contour comprises a collimating lens,

wherein the collimating lens is oriented to project a beam onto the totally internally reflective feature by way of the second optical axis, and

wherein the totally internally reflective feature is operative to reflect the beam through a concave surface of the optic.

10. The illumination system of claim 5, wherein the optic is seamless, and

wherein a light emitting dome of the light emitting diode protrudes into the cavity.

11. The illumination system of claim 5, wherein a gas is disposed between the light emitting diode and the first surface.

12. The illumination system of claim 5, wherein the optic is a unitary piece of molded optical material, and

wherein the refractive contour is concave.

13. An illumination system comprising:

a light emitting diode comprising;

a substrate; and

a dome protruding relative to the substrate, wherein a reference plane that projects away from the substrate sections the dome into a first section disposed on a first side of the reference plane and a second section disposed on a second side of the reference plane; and

an optic comprising a first surface forming a cavity that faces towards the light emitting diode and a second surface, opposite the cavity, that faces away from the light emitting diode,

wherein the second surface comprises a first surface region disposed on the first side of the reference plane and a second surface region disposed on the second side of the reference plane, and

wherein the second surface region is patterned with retroreflectors operative to reflect light across the reference plane and through the first surface region.

14. The illumination system of claim 13, wherein each retroreflector comprises a first face meeting a second face to form a cube edge.

15. The illumination system of claim 13, wherein each retroreflector comprises a first facet meeting a second facet at a substantially perpendicular angle.

16. The illumination system of claim 13, wherein each retroreflector comprises a pair of totally internally reflective surfaces.

17. The illumination system of claim 13, wherein each retroreflector arches relative to the dome.

18. The illumination system of claim 13, wherein the dome is disposed in the cavity, and

wherein one or more of the retroreflectors is elongate and arches.

19. The illumination system of claim 13, wherein each retroreflector comprises a two-bounce retroreflector.

20. The illumination system of claim 13, wherein each retroreflector is adapted to retroreflect first incident rays emitted from the dome via two bounces and to transmit second incident rays emitted from the dome.