LED device for wide beam generation

• US 7,993,036 B2
• Filed: 01/20/2010
• Issued: 08/09/2011
• Est. Priority Date: 02/27/2006
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Illumination Management Solutions Incorporated (Eaton Corporation PLC.)
• Inventors: Holder, Ronald G., Rhoads, Greg
• Primary Examiner(s): Lee; Jong-Suk (James)
• Assistant Examiner(s): Crowe; David R
• Application Number:
  US12/690,821
• Publication Number:
  US 20100165625A1
• Time in Patent Office: 566 Days
• Field of Search: 362/311.01, 362/311.02, 362/311.06, 362/311.15, 362/326, 362/335, 362/336, 362/338
• US Class Current: 362/311.02
• 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 apparatus for illuminating a selected surface comprising:

a light source comprising a one centerline; and

a lens optically coupled to the light source, wherein the lens is operable to primarily refract light collected from the light source into an azimuthally asymmetric illumination pattern having more than one director of principal candela off the centerline so that the maximum candela is off the centerline,

wherein the lens comprises a lens base, and

wherein a surface shape of the lens that is proximate to the lens base and that is between the lens base and the director of principal candela is at least partially undercut.

2. The apparatus of claim 1 where the more than one director of principal candela are each oriented 150°

or more off the centerline.

3. The apparatus of claim 1 where the lens is shaped to refract light onto the illumined selected surface to provide a 50 percent of maximum foot-candle measurement at an angle greater than 15 degrees from the centerline of the azimuthally asymmetric illumination pattern.

4. The apparatus of claim 1 where the surface shape is shaped to reduce or eliminate light in angular directions toward the horizon or above.

5. An apparatus for illuminating a selected surface comprising:

a light source comprising a centerline; and

a lens optically coupled to the light source, wherein the lens is operable to primarily refract light collected from the light source to form an azimuthally asymmetric illumination pattern having more than one director of principal candela off the centerline so that the maximum candela is off the centerline,

where the light source has a centerline plane in which the centerline is located and has a near field,

where the lens has a shape to refract light from the light source into a first portion of a beam across the centerline plane of the light source to shift light from one side of the light source to an opposing side of the light source, and

where the lens is operable to refract light from the near field of the light source into a second portion of the beam that is directed into a direction different from the first portion of the beam.

6. An apparatus for illuminating a selected surface comprising:

a light source providing a centerline; and

a lens optically coupled to the light source, wherein the lens is operable to primarily refract light collected from the light source into an azimuthally asymmetric illumination pattern having more than one director of principal candela off the centerline to provide maximum candela off the centerline,

wherein the light source is an LED,

wherein the lens comprises an LED package providing both protective passivation for the LED and optical processing of light from the LED, and

wherein the apparatus further comprises a plurality of light bars with a plurality of LED packages combined into or onto each of the light bars.

7. The apparatus of claim 6 further comprising a fixture as a luminaire into which the plurality of light bars are mounted.

8. The apparatus of claim 6 where each light bar comprises a planar carrier.

9. An apparatus comprising:

a light source with a radiation pattern having a centerline; and

an azimuthally asymmetric lens optically coupled to the light source, the lens comprising;

more than one azimuthally asymmetric refracting lobe contiguous with an outer surface of the lens; and

a concave outer surface shape on the centerline,

wherein the lens comprises a lens base, and

wherein a surface shape of the lens proximate to the lens base and between the lens base and the refracting lobe is at least partially undercut.

10. The apparatus of claim 9 wherein each of the more than one azimuthally asymmetric lobes is oriented 15°

or more off the centerline.

11. The apparatus of claim 9 where the lens is shaped to direct light onto an illumined surface to provide a 50 percent of maximum foot-candle measurement at an angle greater than 15 degrees from the centerline of the radiation pattern.

12. The apparatus of claim 9, where the light source has a near field,

where the lens has a centerline plane, and

where the surface shape is operable to direct light from the light source into a beam across the centerline plane by a surface portion of the lens disposed in the near field of the light source.

13. The apparatus of claim 9 where the surface shape is shaped to reduce or totally eliminate light in angular directions toward the horizon or above.

14. The apparatus of claim 9 wherein the more than one azimuthally asymmetric refracting lobes are different in shape from each other.

15. The apparatus of claim 9 wherein the more than one azimuthally asymmetric refracting lobes are substantially similar in shape.

16. The apparatus of claim 9 wherein the more than one azimuthally asymmetric refracting lobes produce a beam that is bisymmetric across a plane including the centerline.

17. The apparatus of claim 9 wherein the more than one azimuthally asymmetric refracting lobes have free form shapes.

18. The apparatus of claim 9 wherein all asymmetric refracting lobes extending from the outer surface of the lens are contiguous with the outer surface of the lens.

19. An apparatus comprising:

a light source with a radiation pattern having a centerline; and

an azimuthally asymmetric lens optically coupled to the light source, the lens comprising;

more than one azimuthally asymmetric refracting lobe contiguous with an outer surface of the lens; and

a concave outer surface shape on the centerline,

wherein the light source is an LED,

wherein the lens comprises an LED package providing both protective passivation for the LED and optical processing of light from the LED, and

wherein the apparatus further comprises a plurality of light bars and a plurality of LED packages combined into or onto each of the light bars.

20. The apparatus of claim 19 further comprising a fixture as a luminaire into which the plurality of light bars are mounted.

21. The apparatus of claim 19 where each light bar comprises a planar carrier.