Color mixing optics for LED illumination device

• US 9,736,895 B1
• Filed: 10/03/2014
• Issued: 08/15/2017
• Est. Priority Date: 10/03/2013
• Status: Active Grant

• Current Assignee: Lutron Technology Company LLC
• Original Assignee: Ketra, Inc. (Lutron Electronics)
• Inventors: Dong, Fangxu, Ho, Horace C., Knapp, David J.
• Primary Examiner(s): Le, Don
• Application Number:
  US14/505,671
• Time in Patent Office: 1,047 Days
• Field of Search: 315185 R
• CPC Class Codes: F21K 9/233 specially adapted for generating a spot light distribution, e.g. for substitution of reflector lamps
• CPC Class Codes: F21V 23/0457 the sensor sensing the operating status of the lighting device, e.g. to detect failure of a light source or to provide feedback to the device
• CPC Class Codes: F21V 5/004 using microlenses
• CPC Class Codes: F21V 5/007 Array of lenses or refractors for a cluster of light sources, e.g. for arrangement of multiple light sources in one plane combination of two or more refractors F21V5/008
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: H05B 45/22 using optical feedback
• CPC Class Codes: H05B 45/46 having LEDs disposed in parallel lines

Abstract

Illumination devices with improved color mixing optics are disclosed herein for mixing the colors produced by a multi-colored LED emitter module to produce uniform color throughout the entire beam angle of the output light beam, along with smoother edges and improved center beam intensity. Embodiments disclosed herein include a unique arrangement of multi-color LEDs within an emitter module, a unique exit lens with different patterns of lenslets on opposing sides of the lens, and other associated optical features that thoroughly mix the different color components, and as such, provide uniform color across the output beam exiting the illumination device. Additional embodiments disclosed herein include a unique arrangement of photodetectors within the primary optics structure of the LED emitter module that ensure the optical feedback system properly measures the light produced by all similarly colored emission LEDs.

Claims

1. An illumination device, comprising an emitter module having an array of emission LEDs mounted onto a substrate and encapsulated within a primary optic, wherein the array of emission LEDs comprises four chains of serially connected LEDs with four LEDs in each chain, wherein each chain is configured to produce a different color of light, and wherein each row, column, and diagonal of the 4×

4 array comprises only one LED from each chain.

2. The illumination device as recited in claim 1, wherein the array of emission LEDs comprise a chain of four serially connected white LEDs, a chain of four serially connected red LEDs, a chain of four serially connected green LEDs, and a chain of four serially connected blue LEDs.

3. The illumination device as recited in claim 1, wherein the array of emission LEDs comprise a chain of four serially connected yellow LEDs, a chain of four serially connected red LEDs, a chain of four serially connected green LEDs, and a chain of four serially connected blue LEDs.

4. An illumination device comprising an emitter module having a plurality of emission LEDs mounted onto a substrate and encapsulated within a primary optic, wherein the plurality of emission LEDs are spatially divided into N blocks, wherein N is an integer value greater than or equal to 3, wherein each block consists of N LEDs each configured for producing a different color of light, wherein the N LEDs within each block are arranged to form a polygon having N sides, and wherein the N blocks of LEDs are arranged in a pattern on the substrate to form an outer polygon having N sides;

wherein the N blocks are arranged on the substrate, such that;

one LED within each block is located on a different vertex of an inner polygon having N sides, wherein the LEDs located on the vertices of the inner polygon are each configured to produce a different color of light; and

remaining LEDs within each block are located along the N sides of the outer polygon, wherein the LEDs located along each side of the outer polygon are each configured to produce a different color of light;

wherein if N=4, the four LEDs within each block are arranged to form a square, and

wherein the inner polygon is a square, and wherein the outer polygon is a square.

5. The illumination device as recited in claim 4, wherein the array of emission LEDs comprise a chain of four serially connected white LEDs, a chain of four serially connected red LEDs, a chain of four serially connected green LEDs, and a chain of four serially connected blue LEDs.

6. The illumination device as recited in claim 4, wherein the array of emission LEDs comprise a chain of four serially connected yellow LEDs, a chain of four serially connected red LEDs, a chain of four serially connected green LEDs, and a chain of four serially connected blue LEDs.

7. An illumination device, comprising:

a plurality of emission LEDs mounted onto a substrate and configured to produce illumination for the illumination device, wherein the plurality of emission LEDs are arranged in a pattern on the substrate to form an outer polygon having N sides, wherein N is an integer value greater than or equal to 3;

a primary optic encapsulating the plurality of emission LEDs and configured to transmit a majority of the illumination produced by the emission LEDs; and

N photodetectors mounted onto the substrate and encapsulated within the primary optic, wherein the N photodetectors are arranged around a periphery of the outer polygon, such that the N photodetectors are placed near a center of the N sides of the outer polygon, and wherein the N photodetectors are electrically connected in parallel to receiver circuitry of the illumination device for detecting a portion of the illumination that is emitted by the emission LEDs and/or reflected by the primary optic.

8. The illumination device as recited in claim 7, wherein the plurality of emission LEDs are spatially divided into N blocks, wherein each block consists of N LEDs each configured for producing a different color of light, wherein the N LEDs within each block are arranged to form an inner polygon having N sides, and wherein the N blocks of LEDs are arranged in the pattern on the substrate to form the outer polygon having N sides.

9. The illumination device as recited in claim 7, wherein the plurality of emission LEDs are electrically coupled as N chains of serially connected LEDs with N LEDs in each chain, and wherein each chain is configured to produce a different color of light.

10. The illumination device as recited in claim 9, further comprising:

driver circuitry coupled for driving the N chains of serially connected LEDs with respective drive currents substantially continuously to produce illumination, periodically turning the N chains of serially connected LEDs off for short durations of time to produce periodic intervals, and supplying a respective drive current to each LED chain, one chain at a time, during the periodic intervals to produce illumination from only one LED chain at a time; and

wherein the receiver circuitry coupled to the N photodetectors is configured for detecting a sum of photocurrents, which are induced in the N photodetectors upon receiving a portion of the illumination produced by each LED chain, one chain at a time, during the periodic intervals, and wherein the sum of photocurrents is representative of a total amount of illumination produced by each LED chain.