WO2015085062A4

WO2015085062A4 - Linear led illumination device with improved color mixing

Info

Publication number: WO2015085062A4
Application number: PCT/US2014/068556
Authority: WO
Inventors: Fangxu DONG; Craig T. PHILLIPS; David J. Knapp; Derek Edward LOGAN; Tomas J. MOLLNOW
Original assignee: Ketra, Inc.
Priority date: 2013-12-05
Filing date: 2014-12-04
Publication date: 2015-10-01
Also published as: WO2015085062A2; EP3077721B1; WO2015085062A3; EP3875851A1; EP3077721A2

Abstract

A linear multi-color LED illumination device that produces uniform color throughout the output light beam without using excessively large optics or optical losses is disclosed herein. Embodiments for improving color mixing in the linear illumination device include a shallow dome encapsulating a plurality of emission LEDs within an emitter module, a unique arrangement of a plurality of such emitter modules in a linear light form factor, and special reflectors designed to improve color mixing between the plurality of emitter modules. The illumination device further includes a light detector and optical feedback for maintaining precise and uniform color over time and/or with changes in temperature. The illumination device can include a rotational hinge allowing a power cable of the illumination device to enter and exit through a rotational axis of the hinge, but does not require special tools or an independent locking mechanism to secure in place.

Claims

AMENDED CLAIMS

received by the International Bureau on 12 August 2015 (12.08.2015)

1. An illumination device, comprising:

a plurality of emitter modules spaced apart from each other and arranged in a line,

wherein each emitter module comprises an array of at least two different colors of light emitting diode? (LEDs), which are mounted on a substrate and encapsulated within a shallow dome, and wherein a flattened shape of the shallow dome allows a greater portion of light emitted by the array of LEDs to emanate sideways from the emitter module than a hemispherical shaped dome; and

a reflector comprising a plurality of louvers, wherein each louver is centered upon and suspended a spaced distance above a different one of the emitter modules to focus a majority of light emitted by that emitter module into an output beam, and wherein by suspending the louvers a spaced distance above the emitter modules, each louver is configured to receive the portion of the light that emanates sideways from adjacent emitter modules and reflect the received light to improve color mixing in the output beam.

2. The illumination device as recited in claim 1 , wherein a radius of the shallow dome in a plane of the array of LEDs is 20-30% larger than a radius of a curvature of the hemispherical shaped dome, so that the portion of the light that emanates sideways from the emitter module exits the shallow dome at small angles relative to a plane of the LED array.

3. The illumination device as recited in claim 2, wherein approximately 40% of the light emitted by the array of LEDs exits the shallow dome at approximately 0 to 30 degrees relative to the plane of the LED array.

4. The illumination device as recited in claim 1 , wherein a top diameter of each louver is substantially larger than a bottom diameter of the louver,

5^. The illumination device as recited in claim 4, wherein the plurality of louvers each comprise a substantially circular shape with sloping sidewalls-

6. The illumination device as recited in claim 4, wherein the plurality of louvers each comprise sidewalls with a substantially parabolic shape.

7. The illumination device as recited in claim 4, wherein the louvers are configured to focus the majority of the light emitted by the emitter modules into the output beam by configuring the bottom diameter of the louvers to be substantially larger than a diameter of the emitter modules.

8. The illumination device as recited in claim 5, wherein the sloping sidewalls of the louvers include a plurality of planar facets, which are configured to randomize a direction of light reflected from the planar facets.

9. The illumination device as recited in claim 1, wherein the louvers are suspended approximately 5mm to approximately 10mm above the emitter modules to allow the portion of the light that emanates sideways from the emitter modules to mix underneath the louvers.

10. The illumination device as recited in claim 1, wherein the plurality of emitter modules comprise at least a first emitter module, a second emitter module, and a third emitter module, and wherein:

the second emitter module is spaced equally distant between the first and third emitter modules;

the second emitter module is rotated X degrees relative to the first emitter module;

the third emitter module is rotated 2X degrees relative to the first emitter module; and wherein X is a rotational angle equal to 360 degrees divided by an integer N, where N is greater than or equal to 3.

11. The illumination device as recited in claim 1 , wherein the array of LEDs comprises at least four LEDs, which are mounted on the substrate close together and arranged in a square pattern near a center of the shallow dome.

12. The illumination device as recited in claim 11 , wherein the array of LEDs comprises a red LED, a green LED, a blue LED and a white LED.

13. The illumination device as recited in claim 1 , further comprising:

an emitter housing, wherein the plurality of emitter modules and the reflector reside

within the emitter housing; and

an exit lens mounted above the reflector and attached to sidewalls of the emitter housing.

14. The illumination device as recited in claim 13 , wherein an internal surface of the exit lens comprises a flat roughened surface that scatters light rays passing through the exit lens, and wherein an external surface of the exit lens comprises an array of lenslets that randomizes the scattered light rays-

15. An illumination device, comprising a plurality of emitter modules spaced apart from each other and arranged in a line, wherein each emitter module comprises:

a plurality of light emitting diodes (LEDs), which are arranged in a two-dimensional array, mounted on a substrate and encapsulated within a dome, wherein one or more of the plurality of LEDs is con figured to emit light at a shorter wavelength than the other LEDs; and

a detector configured to detect light emitted from, the plurality of LEDs, wherein the detector is also mounted on the substrate and encapsulated within the dome, and wherein the detector is positioned on a side or near a corner of the array that is furthest from the one or more LEDs configured to emit light at the shorter wavelength.

16. The illumination device as recited in claim 15, wherein the plurality of LEDs comprises at least four LEDs, which are mounted on the substrate close together and arranged in a square array near a center of the dome.

17. The illumination device as recited in claim 15, wherein the plurality of LEDs comprises a red LED, a green LED, a blue LED and a white LED.

18. The illumination device as recited in claim 17, wherein the detector comprises a red LED. an orange LED or a yellow LED, and wherein the detector is positioned on the side or near the comer of the array that is furthest from the blue LED.

19. The illumination device as recited in claim 15, wherein the dome is formed from an optically transmissive material, and wherein the dome comprises a textured sutface that is configured to reflect a small portion of the emitted light back toward the detector.

20. The illumination device as recited in claim 15, further comprising:

a plurality of driver circuits coupled to the plurality of LEDs for supplying drive currents thereto, wherein during a compensation period, the plurality of driver circuits are configured to supply drive currents to the plurality of LEDs, one LED at a time, so that the detector can detect the light emitted by each individual LED;

a receiver coupled to the detector for monitoring the light emitted by each individual LED and detected by the detector during the compensation period; and control logic coupled between the receiver and the driver circuits, wherein the control logic is configured to control the drive currents produced by driver circuits, so as to adjust an intensity of the light emitted by each individual LED.

21. An illumination device, comprising:

an emitter housing comprising a plurality of LED emitter modules;

a power supply housing coupled to the emitter housing and comprising an orifice through which a power cable is routed;

a mounting bracket for mounting the illumination device to a surface; and

a hinge mechanism coupled between the emitter housing and the mounting bracket,

wherein the hinge mechanism allows the emitter housing to rotate approximately 180 degrees relative to the mounting bracket around a rotational axis of the hinge mechanism, and wherein the hinge mechanism enables the power cable to be routed through the orifice of the power supply housing along the rotational axis of the hinge mechanism by positioning rotational components of the hinge mechanism away from the rotational axis of the hinge mechanism.

22. The illumination device as recited in claim 21 , wherein the hinge mechanism comprises: a swing arm, wherein one end of the swing arm is attached to the mounting bracket; an end cap having a flat upper surface for attachment to the emitter housing and a semicircular inner surface comprising a plurality of teeth; and

a hinge element that extends outward from within the swing arm, wherein the hinge element comprises a position holding gear configured to interface with the teeth on the semi-circular inner surface of the end cap to secure the illumination device in substantially any rotational position.

23. The illumination device as recited in claim 22, wherein the position holding gear of the hinge element is configured to travel around the semi-circular inner surface of the end cap in an arc, whose radius is a fixed distance away from the rotational axis of the hinge mechanism,

24. The illumination device as recited in claim 22, wherein, an opposite end of the swing arm is coupled near the flat upper surface of the end cap and centered about the rotational axis of the hinge mechanism.

25. The illumination device as recited in claim 24, wherein the opposite end of the swing arm comprises a cabl e exit gland, which is aligned with the orifice of the power supply housi ng for routing the power cable into the power supply housing at the rotational axis of the hinge mechanism.

26. The illumination device as recited in claim 22, wherein the hinge element further comprises a constant torque element that provides a substantially consistent amount of torque to the position holding gear, regardless of whether the position holding gear is stationary or in motion.

27. The illumination device as recited in claim 22, wherein the hinge element further comprises a variable torque element that requires a larger amount of torque to move the position holding gear from a stationary position, and a smaller amount of torque once the position holding gear is in motion.

28. The illumination device as recited in claim 22, wherein the hinge mechanism enables the illumination device to be adjusted about the rotational axis and secured in a rotational position without tools.

29. The illumination device as recited in claim 22, wherein the hinge mechanism enables the illumination device to be secured in a rotational position without an additional locking mechanism.

STATEMENT UNDER ARTICLE 19 (1 )

This paper is submitted in response to the International Search Report and Written Opinion mailed 22 June 2015 to explain the relevance of at least some of the claim amendments.

As noted in the accompanying Section 205(b) Letter for Amendments under Article 19, claims 1, 2, 8, and 9 are replaced by amended claims bearing the same numbers. Specifically, independent claim 1 is amended to clarify that, by suspending the louvers a spaced distance above the emitter modules, each louver is configured to receive the portion of the light that emanates sideways from adjacent emitter modules and reflect the received light to improve color mixing in the output beam; claim 2 is amended to correct an error; and claims 8-9 are amended to correct dependency.