Uniform luminance and color mixing lens for LED device

• US 20060262539A1
• Filed: 05/23/2005
• Published: 11/23/2006
• Est. Priority Date: 05/23/2005
• Status: Active Grant

• Current Assignee: Ascom (Sweden) AB (Ascom Holding AG)
• Original Assignee: GE Security Incorporated (Carrier Global Corporation)
• Inventors: Drouin, Guy, Beaumont, Martin, Goulet, Rene
• Granted Patent: US 7,270,447 B2
• Time in Patent Office: Days
• US Class Current: 362/335
• CPC Class Codes: F21V 13/04 the elements being reflectors and refractors for vehicle rear lights F21S43/40
• CPC Class Codes: F21V 5/04 of lens shape
• 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 19/0066 in the form of an LED array
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A lens for an LED having a lens body providing total internal reflection of light emitted by the LED from a first emission point disposed proximate a first junction of the lens body and centerplane. The lens includes an arcuate light-diffusing edge for diffusing light emitted by the LED and reflected by the angular base and sidewall assembly, the light being diffused by the lens at substantially uniform luminance across a sector of at least 150 degrees centered and measured about the first junction. The light diffused by the lens provides for substantially uniform mixing of at least two different colors of light emitted by a multi-color LED apparatus disposed at the first emission point.

Claims

1. A lens for an LED, comprising:

a lens body having a centerplane dividing the lens body into symmetric halves, each half having an angular base having

a first reflection surface extending substantially perpendicular from the centerplane at a first junction of the lens body and centerplane, the first junction being substantially proximate a first emission point of the LED, and

a second reflection surface extending from a distal end of said first reflection surface at an angle having a range of 130 to 150 degrees measured from a line connecting the distal end and first junction, wherein a plane extending along the second reflection surface intersects a distal edge of the half at an intersection point, the intersection point being at an angle having a range of 64 to 74 degrees from the centerplane, measured about the first junction.

2. The lens of claim 1, wherein each half of the lens body further comprises:

an arcuate light-diffusing surface having proximal and distal portions and extending from the intersection point to a second junction of the centerplane and lens body, the lens body having a height defined by the distance between the first and second junctions, the proximal portion having a radius of curvature having a range of 1.75 to 2.15 times the height, the distal portion having a radius of curvature having a range of 0.25 to 0.32 times the height.

3. The lens of claim 2, wherein the proximal portion of the light-diffusing surface traces an angle having a range of 20 to 24 degrees about a center of curvature for the proximal portion, and the distal portion of the light-diffusing surface traces an angle in having a range of 50 to 54 degrees about a center of curvature for the distal portion.

4. The lens of claim 3, wherein the arcuate light-diffusing surface has a surface texture of VDI-42.

5. The lens of claim 2, wherein each half of the lens body further comprises:

first and second light-opaque sidewalls substantially parallel to each other, the sidewalls extending substantially perpendicular from opposite edges of the centerplane between the first and second junctions and extending to the angular base and arcuate light-diffusing surface.

6. The lens of claim 5, wherein the first reflection surface defines a first plane extending from the first junction perpendicular to the centerplane and defines a frustum of a skewed pyramid extending from a distal end of the first plane, the frustum extending outwards with respect to the lens body and having

congruent side planes extending from the first and second sidewalls to an apical plane of the frustum,

a proximal side plane extending from the distal end of the first plane between the congruent side planes to a proximal end of the apical plane, and

a distal side plane extending from a distal end of the apical plane to a proximal end of the second reflection surface.

7. The lens of claim 6, wherein the proximal side plane of the frustum defines an angle having a range of 90 to 100 degrees measured from the first plane about the distal end of the first plane.

8. The lens of claim 7, wherein the distal side plane of the frustum defines an angle having a range of 47 to 58 degrees measured from a line extending distally from the apical plane about the distal end of the apical plane.

9. The lens of claim 5, wherein the apical plane is adapted to be disposed against a second emission point for an LED.

10. The lens of claim 5, wherein the sidewalls are spaced apart at a distance having a range of 0.17 to 0.21 times the height.

11. The lens of claim 5, wherein the first and second sidewalls and angular base have a surface texture of SPI-A2.

12. A lens for an LED having a lens body having a centerplane, comprising:

an angular base and sidewall assembly for total internal reflection of light emitted by the LED from a first emission point disposed proximate a first junction of the lens body and centerplane, and

an arcuate light-diffusing surface for diffusing light emitted by the LED and reflected by the angular base and sidewall assembly, the light being diffused by the lens at substantially uniform luminance across a sector of at least 150 degrees centered and measured about the first junction.

13. The lens of claim 12, wherein the light diffused by the lens provides for substantially uniform mixing of at least two different colors of light emitted by a multi-color LED apparatus disposed at the first emission point.

14. The lens of claim 12, wherein the angular base and sidewall assembly further comprises:

a reflection surface for total internal reflection of light from at least two LED elements disposed at opposite sides of the first emission point and offset from the centerplane, defining a second and third emission point for the lens.

15. The lens of claim 14, wherein the at least two LED elements are monochromatic LED elements.

16. The lens of claim 12, wherein the angular base and sidewall assembly has a surface texture of SPI-A2.

17. The lens of claim 12, wherein the arcuate light-diffusing surface has a surface texture of VDI-42.

18. A method of focusing and directing light emitted by an LED, comprising:

reflecting and refracting light emitted from a first emission point of the LED through a lens body having a centerplane dividing the lens body into symmetric halves, each half having an angular base having

a first reflection surface extending substantially perpendicular from the centerplane at a first junction of the lens body and centerplane, the first junction being substantially proximate the first emission point of the LED, and

a second reflection surface extending from a distal end of said first reflection surface at an angle having a range of 130 to 150 degrees measured from a line connecting the distal end and first junction, wherein a plane extending along the second reflection surface intersects a distal edge of the half at an intersection point, the intersection point being at an angle having a range of 64 to 74 degrees from the centerplane, measured about the first junction.

19. The method of claim 18, further comprising:

applying a texture of SPI-A2 to the angular base.

20. The method of claim 18, wherein each half of the lens body further comprises an arcuate light-diffusing surface having proximal and distal portions and extending from the intersection point to a second junction of the centerplane and lens body, the lens body having a height defined by the distance between the first and second junctions, the proximal portion having a radius of curvature having a range of 1.75 to 2.15 times the height, the distal portion having a radius of curvature having a range of 0.25 to 0.32 times the height, and further comprising:

applying a texture of VDI-42 to the light-diffusing arcuate edge.