Ambient light monitoring in a lighting fixture

• US 10,161,612 B2
• Filed: 03/15/2013
• Issued: 12/25/2018
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: IDEAL Industries Lighting, LLC (Ideal Industries Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Chobot, Joseph P., Pope, Daniel J.
• Primary Examiner(s): Song, Zheng
• Application Number:
  US13/838,398
• Publication Number:
  US 20140268790A1
• Time in Patent Office: 2,111 Days
• Field of Search: 3622171-21713, 362276, 36231101, 36231102, 362511, 315154
• CPC Class Codes: F21S 2/00 Systems of lighting devices, not provided for in main groups F21S4/00 - F21S10/00 or F21S19/00, e.g. of modular construction
• CPC Class Codes: F21S 8/026 intended to be recessed in a ceiling or like overhead structure, e.g. suspended ceiling
• CPC Class Codes: F21V 23/0464 the sensor sensing the level of ambient illumination, e.g. dawn or dusk sensors
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/175 by remote control
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

A lighting fixture employing a solid-state light source and an ambient light sensor is disclosed. The solid-state light source is placed within a light source housing and configured to emit light through a lens assembly that covers an opening into a mixing chamber provided within the light source housing. In one embodiment, the ambient light sensor is located within mixing chamber with the solid-state light source. In another embodiment, the ambient light sensor is located outside of the mixing chamber. In either embodiment, the ambient light sensor may be recessed within a waveguide, which aides in controlling the sensor distribution beam for the ambient light sensor. The sensor distribution beam essentially defines an area from which light reflected off of a task surface is accurately monitored via the ambient light sensor. The direction of the sensor distribution beam and the light emitted from the ambient light sensor may generally coincide.

Claims

1. A lighting fixture comprising:

a frame;

a lens assembly;

a light source housing mounted on the frame, the light source housing having an opening covered by the lens assembly and providing a mixing chamber;

a solid-state light source mounted within the mixing chamber;

an ambient light sensor mounted outside of the mixing chamber and coupled to the frame;

a waveguide mounted outside of the mixing chamber where the ambient light sensor is recessed in the waveguide,

wherein a sensor distribution beam that defines a sensor coverage area on a task surface is provided by the ambient light sensor via the waveguide and is directed in a first direction and a light distribution beam that defines a light coverage area on the task surface is provided by the solid-state light source via the lens assembly and is directed in the first direction such that the sensor coverage area is completely within the light coverage area; and

a driver module coupled to the ambient light sensor and the solid-state light source, the driver module adapted to;

drive the solid-state light source;

read a first output from the ambient light sensor with the solid-state light source driven at a first output level;

read a second output from the ambient light sensor with the solid-state light source driven at a second output level;

determine a setpoint based on a difference between the first output and the second output relative to a difference between the first output level and the second output level;

periodically adjust the setpoint to effectively raise or lower a light level of the lighting fixture; and

receive an output of the ambient light sensor and drive the solid-state light source such that the output of the ambient light sensor corresponds to the setpoint.

2. The lighting fixture of claim 1 wherein the light distribution beam is broader than the sensor distribution beam.

3. The lighting fixture of claim 1 wherein the first output level corresponds to the solid-state light source being driven to a fully on state.

4. The lighting fixture of claim 3 wherein the second output level corresponds to the solid-state light source being off.

5. The lighting fixture of claim 1 wherein the first output level corresponds to the solid-state light source being off.

6. The lighting fixture of claim 1 wherein the first output level corresponds to the solid-state light source being driven to a fully on state and the second output level corresponds to the solid-state light source being off.

7. The lighting fixture of claim 1 wherein the first output level corresponds to the solid-state light source being driven at a first dimming level and the second output level corresponds to the solid-state light source being driven at a second dimming level, which is different from the first dimming level.

8. The lighting fixture of claim 1 wherein as the driver module monitors the output of the ambient light sensor, the driver module continues to drive the solid-state light source, such that the lighting fixture is outputting light as the ambient light sensor is being monitored.

9. The lighting fixture of claim 1 wherein the driver module is further adapted to drive the solid-state light source such that the output of the ambient light sensor corresponds to the setpoint, which corresponds to a reference light level being reflected off of the task surface, the task surface being partially illuminated by the lighting fixture.

10. The lighting fixture of claim 1 wherein the driver module is further adapted to read the output of the ambient light sensor and effect delivery of the output to at least one other lighting fixture.

11. The lighting fixture of claim 1 wherein the solid-state light source comprises a plurality of LEDs.

12. The lighting fixture of claim 11 wherein the plurality of LEDs comprises at least one LED that emits light at a first color and at least one other LED that emits light at a second color that is different than the first color.

13. The lighting fixture of claim 1 wherein the first output level corresponds to a first dimming level and the second output level corresponds to a second dimming level.

14. A lighting fixture comprising:

a frame;

a lens assembly;

a light source housing mounted on the frame and having an opening covered by the lens assembly;

a solid-state light source mounted to the light source housing;

an ambient light sensor mounted outside of the light source housing, wherein a sensor distribution beam that defines a sensor coverage area on a task surface is provided by the ambient light sensor via a waveguide and is directed in a first direction and a light distribution beam that defines a light coverage area on the task surface is provided by the solid-state light source via the lens assembly and is directed in the first direction such that the sensor coverage area is completely within the light coverage area; and

a driver module coupled to the ambient light sensor and the solid-state light source, the driver module adapted to;

drive the solid-state light source;

read a first output from the ambient light sensor with the solid-state light source driven at a first output level;

read a second output from the ambient light sensor with the solid-state light source driven at a second output level;

determine a setpoint based on a difference between the first output and the second output relative to a difference between the first output level and the second output level;

periodically adjust the setpoint to effectively raise or lower a reference light level of the lighting fixture; and

receive an output of the ambient light sensor and drive the solid-state light source such that the output of the ambient light sensor corresponds to the setpoint.

15. The lighting fixture of claim 14 wherein the light distribution beam is broader than the sensor distribution beam.

16. The lighting fixture of claim 14 wherein the first output level corresponds to a first dimming level and the second output level corresponds to a second dimming level.