LED device for wide beam generation

• US 7,942,559 B2
• Filed: 01/20/2010
• Issued: 05/17/2011
• Est. Priority Date: 02/27/2006
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Cooper Technologies Company (Eaton Corporation PLC.)
• Inventors: Holder, Ronald G., Rhoads, Greg
• Primary Examiner(s): Truong; Bao Q
• Application Number:
  US12/690,794
• Publication Number:
  US 20100128489A1
• Time in Patent Office: 482 Days
• Field of Search: 362/311.06, 362/308, 362/309, 362/311.02, 362335-340, 362326-334
• US Class Current: 362/311.06
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: F21K 9/69 Details of refractors forming part of the light source
• CPC Class Codes: F21S 8/085 of high-built type, e.g. street light
• CPC Class Codes: F21S 8/086 with lighting device attached sideways of the standard, e.g. for roads and highways
• CPC Class Codes: F21V 13/04 the elements being reflectors and refractors for vehicle rear lights F21S43/40
• CPC Class Codes: F21V 19/02 with provision for adjustment, e.g. for focusing
• CPC Class Codes: F21V 23/005 the substrate is supporting also the light source
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 31/005 Sealing arrangements therefor
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21W 2131/103 of streets or roads
• CPC Class Codes: F21Y 2105/16 square or rectangular, e.g. for light panels
• 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 19/0071 adapted to illuminate a complete hemisphere or a plane extending 360 degrees around the source
• CPC Class Codes: G02B 27/0012 Optical design, e.g. procedures, algorithms, optimisation routines
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

An apparatus and method is characterized by providing an optical transfer function between a predetermined illuminated surface pattern, such as a street light pattern, and a predetermined energy distribution pattern of a light source, such as that from an LED. A lens is formed having a shape defined by the optical transfer function. The optical transfer function is derived by generating an energy distribution pattern using the predetermined energy distribution pattern of the light source. Then the projection of the energy distribution pattern onto the illuminated surface is generated. The projection is then compared to the predetermined illuminated surface pattern to determine if it acceptably matches. The process continues reiteratively until an acceptable match is achieved. Alternatively, the lens shape is numerically or analytically determined by a functional relationship between the shape and the predetermined illuminated surface pattern and predetermined energy distribution pattern of a light source as inputs.

Claims

1. An improvement in a lens for use in an apparatus for providing a predetermined illuminated surface pattern on an illuminated surface from a predetermined energy distribution pattern of a light source, the light source having a near field and at least a portion of light from the light source being transmitted into a peripheral forward solid angle, the improvement comprising an undercut surface defined on the lens, the lens having a base adjacent to the light source, having a lens axis and having a surface between the base and lens axis including the undercut surface'"'"' and a blob zone, the undercut surface extending from the base of the lens at least partially along the surface of the lens toward the lens axis, the undercut surface positioned to intercept light in the near field of the light source in the peripheral forward solid angle of light from the light source, and the undercut surface being characterized by a smaller outer diameter defined from the lens axis at the base of the lens than the outer diameter of the lens in the blob zone, so that the undercut surface of the lens falls away or narrows at some point as the base of the lens is approached.

2. The improvement of claim 1, further comprising the undercut surface defining an energy distribution pattern using the predetermined energy distribution pattern of a light source and projecting the energy distribution pattern onto the illuminated surface.

3. The improvement of claim 2, wherein the projection of the energy distribution pattern matches the predetermined illuminated surface pattern.

4. The improvement of claim 1, wherein the undercut surface comprises portions which refract light from the light source into the energy distribution pattern.

5. The improvement of claim 1, wherein the undercut surface comprises portions which totally internally reflect light from the light source into the energy distribution pattern.

6. The improvement of claim 1, wherein the undercut surface comprises portions which direct light from the light source into a broad spread beam.

7. The improvement of claim 1, wherein the lens has a shape defined by an optical transfer function between the predetermined illuminated surface pattern and the predetermined energy distribution pattern of the light source.

8. The improvement of claim 7, wherein the shape of the lens is derived by generating an energy distribution pattern using the predetermined energy distribution pattern of the light source and then generating a projection of the energy distribution pattern onto the illuminated surface from the energy distribution pattern, which projection acceptably matches the predetermined illuminated surface pattern.

9. The improvement of claim 1, wherein the lens is azimuthally symmetric.