Lighting device with inner and outer heat sinks having different thermal conductivities
A lighting device (e.g., a controllable light-emitting diode illumination device) may have a light-generation module that may be assembled and calibrated prior to the light-generation module being installed in a finished good. The light-generation module may include an emitter module having at least one emitter mounted to a substrate and configured to emit light. The light-generation module may include a first printed circuit board on which the emitter module may be mounted and a second printed circuit board on which those circuits that are essential for powering the emitter module may be mounted. The light-generation module may include a heat sink located between the first printed circuit board and the second printed circuit board. The emitter module may be thermally-coupled to the heat sink through the substrate and the first printed circuit board.
1 . A lighting device comprising:
a light-generation module comprising:
an emitter configured to emit light; and
a first heat sink defining a planar front surface having a circular periphery, the first heat sink further comprising a sidewall extending from the periphery of the front surface, the emitter thermally coupled to the front surface of the first heat sink;
a second heat sink defining a cavity in which the first heat sink is located, the second heat sink thermally coupled to the sidewall of the first heat sink;
a first printed circuit board attached to the front surface of the first heat sink; and
a second printed circuit board attached to a rear surface of the first heat sink, the second printed circuit board having a drive circuit for the emitter mounted thereto, a control circuit for controlling the drive circuit, and a wireless communication circuit configured to communicate wireless signals;
wherein the first heat sink is smaller in volume than the second heat sink, and the first heat sink is made from a first material that is more thermally conductive than a second material of the second heat sink.
2 . The lighting device of claim 1 , wherein the light-generation module further comprises an antenna electrically coupled to the wireless communication circuit on the second printed circuit board, the antenna extending through a bore defined through the first heat sink and an opening in the first printed circuit board.
3 . The lighting device of claim 2 , further comprising:
a lens through which the light from the emitter is emitted; and
a reflector configured to reflect light emitted by the emitter towards the lens,
wherein the lens, the reflector, and the first printed circuit board define an optical cavity, and wherein the antenna extends through the bore defined through the first heat sink and the opening in the first printed circuit board, such that the antenna extends into the optical cavity.
4 . The lighting device of claim 3 , further comprising:
a shield located over a top surface of the first printed circuit board in the optical cavity, the shield configured to be electrically coupled to the first heat sink to reduce noise from the second printed circuit board from coupling to the reflector of the lighting device.
5 . The lighting device of claim 4 , wherein a top side of the shield is electrically coupled to the first heat sink, and a bottom side of the shield is not electrically conductive such that the first printed circuit board is electrically isolated from the shield.
6 . The lighting device of claim 3 , wherein the antenna is straight and a distal portion of the antenna is configured to abut an inner surface of the lens.
7 . The lighting device of claim 3 , wherein the antenna is bent, so as to avoid having the antenna contact an inner surface of the lens.
8 . The lighting device of claim 1 , wherein the light-generation module further comprises an insulator configured to be received in a first recess in the rear surface of the first heat sink, the insulator configured to electrically isolate the drive circuit, the control circuit, and the wireless communication circuit from the first heat sink.
9 . The lighting device of claim 1 , wherein the first heat sink is configured to radiate heat generated by the emitter out the sidewall to the second heat sink.
10 . The lighting device of claim 9 , wherein the second heat sink is a portion of an enclosure of the lighting device.
11 . The lighting device of claim 1 , wherein the light-generation module is configured to be press fit into the second heat sink.
12 . The lighting device of claim 11 , wherein the light-generation module is capable of removal from the second heat sink such that it is replaceable.
13 . The lighting device of claim 1 , wherein the first heat sink is configured to radiate heat generated by the emitter radially out through the sidewall to the second heat sink.
14 . The lighting device of claim 1 , wherein the emitter is mounted to a substrate which is attached to the front surface of the first heat sink.
15 . A lighting device comprising:
a light-generation module comprising:
an emitter configured to emit light; and
a first heat sink defining a front surface, the emitter thermally coupled to the front surface of the first heat sink;
a second heat sink defining a cavity in which the first heat sink is located, the second heat sink thermally coupled to the first heat sink;
a first printed circuit board attached to the front surface of the first heat sink; and
a second printed circuit board attached to a rear surface of the first heat sink, the second printed circuit board comprising a drive circuit for the emitter and a control circuit for controlling the drive circuit,
wherein the first heat sink is smaller in volume than the second heat sink, and the first heat sink is made from a first material that is more thermally conductive than a second material of the second heat sink.
16 . The lighting device of claim 15 , wherein the front surface of the first heat sink is planar and has a circular periphery.
17 . The lighting device of claim 16 , wherein the first heat sink further comprises a flange extending about the periphery of the first heat sink.
18 . The lighting device of claim 16 , wherein the first heat sink further comprising a sidewall extending from the periphery of the front surface, the second heat sink thermally coupled to the sidewall of the first heat sink.
19 . The lighting device of claim 15 , wherein the second printed circuit board comprises a wireless communication circuit configured to communicate wireless signals.
20 . The lighting device of claim 15 , wherein the emitter is mounted to a substrate which is attached to the front surface of the first heat sink.
21 . The lighting device of claim 20 , wherein a bottom surface of the substrate comprises:
a plurality of electrical pads grouped together in sets of multiple pads, the electrical pads coupled to corresponding electrical pads on a top side of the first printed circuit board; and
one or more heat sink pads, the heat sink pads comprising a central pad and four corner pads located in respective corners of the substrate.
22 . The lighting device of claim 21 , wherein at least one of the sets of electrical pads on the bottom surface of the substrate is surrounded by an electrostatic discharge trace that is connected to a ground plane of the first printed circuit board.