Peripheral optical element for redirecting light from an LED

• US 5,592,578 A
• Filed: 11/01/1995
• Issued: 01/07/1997
• Est. Priority Date: 11/01/1995
• Status: Expired due to Term

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Ruh, Richard A.
• Primary Examiner(s): Ullah, Akm E.
• Application Number:
  US08/548,309
• Time in Patent Office: 433 Days
• Field of Search: 385/31, 385/39, 385/53, 385/147
• US Class Current: 385/31
• CPC Class Codes: F21K 9/68 Details of reflectors forming part of the light source
• CPC Class Codes: F21S 43/14 Light emitting diodes [LED]
• CPC Class Codes: F21V 7/0083 Array of reflectors for a cluster of light sources, e.g. arrangement of multiple light sources in one plane combination of two or more reflectors F21V7/0025
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• 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 6/4298 coupling with non-coherent light sources and/or radiation detectors, e.g. lamps, incandescent bulbs, scintillation chambers
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

A peripheral optical element efficiently collects light emitted by a light emitting diode (LED) to produce a high luminous intensity of emitted light within a limited viewing angle relative to an optical axis. An LED is positioned in the center of the peripheral optical element, the element comprising a base, a refractive and reflective surface, and an exiting surface. In one preferred embodiment of the present invention, the peripheral optical element is radially symmetric to form a ring element. In an alternative embodiment of the present invention an array of multiple peripheral optical elements is mounted in a frame to accommodate multiple LEDs, forming a light panel for power signaling applications.

Claims

1. A peripheral optical element for redirecting dispersed light into a predetermined viewing angle relative to an optical axis, the peripheral optical element comprising:

a pair of coplanar base surfaces each having an inside and an outside edge, perpendicular to the optical axis, offset from the optical axis;

a pair of refracting surfaces, each refracting surface adjacent to the inside edge of each base surface and at a first acute angle to the optical axis;

a pair of reflecting surfaces, each reflecting surface adjacent to the outside edge of each base surface, and at a second acute angle to the optical axis wherein the second acute angle is greater than the first acute angle; and

a pair of exiting surfaces adjacent to the reflecting and refracting surfaces.

2. The peripheral optical element of claim 1 wherein the pair of exiting surfaces is coplanar and parallel to the pair of coplanar base surfaces.

3. The peripheral optical element of claim 2 wherein the base surfaces, the refracting surfaces, and the exiting surfaces are optically transmissive.

4. The peripheral optical element of claim 3 wherein the reflecting surfaces are optically transmissive.

5. The peripheral optical element of claim 3 wherein the refracting surfaces, the reflecting surfaces, the base surfaces and the exiting surfaces are rotationally symmetric about the optical axis.

6. A light source producing a cone of luminous intensity centered about an optical axis, comprising:

a radially symmetric peripheral optical element defined by;

a pair of conic surfaces disposed about the optical axis, the first conic surface of the pair at a first acute angle to the optical axis, the second conic surface of the pair at a second acute angle to the optical axis greater than the first acute angle,

an annular base surface formed by truncating the cones in a first plane perpendicular to the optical axis; and

an annular exit surface formed by truncating the cones in a second plane perpendicular to the optical axis; and

a light emitting diode centered within the annular base surface.

7. The light source of claim 6 wherein the first conic surface, the annular base surface and the annular exit surface are optically transmissive to light produced by the light emitting diode.

8. The light source of claim 7 wherein the second conic surface is optically transmissive to light produced by the light emitting diode.

9. The light source of claim 8 wherein the peripheral optical element is fabricated from polymethyl methacrylate.

10. The light source of claim 8 wherein the peripheral optical element is fabricated from polycarbonate.

11. An array of peripheral optical elements for directing light within a predetermined viewing angle relative to an optical axis, comprising:

multiple peripheral optical elements, in cross-section each peripheral optical element including;

a pair of coplanar base surfaces each having an inside and an outside edge, perpendicular to the optical axis, offset from the optical axis,

a pair of refracting surfaces, each refracting surface adjacent to the inside edge of each base surface and at a first acute angle to the optical axis,

a pair of reflecting surfaces, each reflecting surface adjacent to the outside edge of each base surface, and at a second acute angle to the optical axis wherein the second acute angle is greater than the first acute angle,

a pair of coplanar exiting surfaces, each exiting surface perpendicular to the optical axis, adjacent to the reflecting and refracting surfaces; and

a frame, continuous with the multiple peripheral optical elements.

12. The array of claim 11 further comprising multiple light emitting diodes, each light emitting diode positioned coplanar to the base surface of a corresponding peripheral optical element of the array.