Systems and methods for providing a self-adjusting light source

• US 9,345,098 B2
• Filed: 05/28/2014
• Issued: 05/17/2016
• Est. Priority Date: 05/31/2013
• Status: Active Grant

• Current Assignee: Signify North America Corporation (Signify N.V.)
• Original Assignee: Stack Labs, Inc.
• Inventors: Joseph, Neil, Gacusan, Jovi
• Primary Examiner(s): VU, JIMMY T
• Application Number:
  US14/288,911
• Publication Number:
  US 20140354150A1
• Time in Patent Office: 720 Days
• Field of Search: 315/209.R, 315224-225, 315/291, 315/307, 315/308
• US Class Current: 1/1
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/22 using optical feedback

Abstract

System, methods, and apparatus, including devices and software, for providing self-adjusting light sources. In one aspect, a lighting unit includes one or more LEDs and an ambient light sensor. The light sensor measures ambient light in synchronization with intermittent off periods of light generated by the LEDs. For example, the LEDs in the lighting unit can be driven by a pulse width modulated signal that turns on and off the LEDs in an alternating manner, and the ambient light can be measured when the LEDs are turned off. In some implementations, a compact lighting unit, such as a light bulb, is provided that can be easily attached to standard light fixtures and can efficiently control its own brightness based on ambient light conditions.

Claims

1. A lighting unit, comprising:

an LED component including one or more light emitting diodes (LEDs) configured to emit light from the lighting unit;

an LED driver connected to the LED component configured to provide current to the one or more light emitting diodes;

a light sensor configured to receive light from a surrounding of the lighting unit and to provide a light intensity signal based on the received light;

an LED controller configured to provide a drive control signal to the LED driver, wherein the drive control signal includes intermittent periods during which the intensity of the light emitted by the LED component is lowered, wherein the LED controller is configured to lower the intensity of the light emitted by the LED component multiple times per second; and

a measuring component configured to measure the light intensity signal from the light sensor in synch with two or more of the intermittent periods in the drive control signal and to provide the measured light intensity to the LED controller.

2. The lighting unit of claim 1, wherein the LED component and the light sensor are components of a single light bulb.

3. The lighting unit of claim 1, wherein the LED controller is configured to adjust the drive control signal based on the measured light intensity and a user setting.

4. The lighting unit of claim 1, further comprising a housing configured to attach the lighting unit to a light fixture and to couple external power to the LED driver.

5. The lighting unit of claim 4, wherein the housing has a bulged reflector (BR) design or a parabolic aluminized reflector (PAR) design.

6. The lighting unit of claim 4, wherein the housing includes the light sensor and the LED component.

7. The lighting unit of claim 1, wherein the LEDs comprise one or more organic light emitting diodes (OLEDs).

8. The lighting unit of claim 1, wherein the LED component includes LEDs emitting light with different colors, and wherein the LED component is configured to enable shifting a color of the light emitted by the LED component based on a signal from the LED driver.

9. The lighting unit of claim 8, wherein the LED component is configured to enable the shifting of the color by changing a wavelength of light emitted or by filtering light emitted.

10. The lighting unit of claim 1, wherein the light sensor includes a photopic sensor configured to provide a light intensity signal that approximates a response of the human eye.

11. The lighting unit of claim 1, wherein the light sensor includes a photodiode or a photoresistor.

12. The lighting unit of claim 1, wherein the LED component and the light sensor are positioned to limit an amount of light from the LED component that is directly received by the light sensor.

13. The lighting unit of claim 1, wherein the LED controller is configured to provide a pulse width modulated drive control signal to the LED driver to turn on and off the current to the one or more light emitting diodes in an alternating manner.

14. The lighting unit of claim 13, wherein the measuring component is configured to measure the light intensity signal when the pulse width modulated drive control signal turns off the current to the one or more light emitting diodes.

15. The lighting unit of claim 14, wherein the LED controller is further configured to modify the pulse width modulated drive control signal to turn off the current to the one or more light emitting diodes when the light intensity measurements are performed.

16. The lighting unit of claim 13, further comprising a synchronization mechanism configured to generate a measurement synch signal to synchronize the pulse width modulated drive control signal with the light intensity measurements in the measuring component.

17. The lighting unit of claim 16, wherein the measurement synch signal includes a periodic signal.

18. The lighting unit of claim 16, wherein the measurement synch signal includes a pseudo-random signal.

19. The lighting unit of claim 1, further comprising an occupancy sensor configured to provide an occupancy signal to the measuring component, wherein the measuring component is further configured to provide occupancy measurements for the LED controller based on the occupancy signal.

20. The lighting unit of claim 1, further comprising a non-light environment sensor, wherein the lighting unit is configured to adjust a color of the light emitted by the LEDs based on a signal from the non-light environment sensor.

21. A method for operating a lighting unit including an LED component having one or more light emitting diodes (LEDs) configured to emit light from the lighting unit and a light sensor configured to receive light from a surrounding of the lighting unit, the method comprising:

providing current to the one or more LEDs;

controlling the current to the one or more LEDs using a drive control signal that includes intermittent periods during which the intensity of the light emitted by the LED component is lowered, wherein the LED controller is configured to lower the intensity of the light emitted by the LED component multiple times per second;

providing a light intensity signal based on the light received by the light sensor; and

performing measurements of the light intensity signal from the light sensor in synch with two or more of the intermittent periods in the drive control signal.

22. The method of claim 21, further comprising using the measurements of the light intensity signal to adjust the drive control signal.

23. The method of claim 22, wherein using the measurements of the light intensity signal includes processing the measurements to determine whether the brightness of the LEDs should be changed.

24. The method of claim 21, wherein adjusting the drive control signal includes receiving a user setting and adjusting the drive control signal in accordance with the received user setting.

25. The method of claim 21, wherein the method further comprises:

providing an occupancy signal; and

adjusting the drive control signal includes adjusting the drive control signal based on the occupancy signal.

26. The method of claim 21, wherein the method further comprises:

adjusting the drive control signal to shift a color of the light emitted by the LEDs.

27. The method of claim 21, wherein performing measurements of the light intensity signal from the light sensor in synch with the intermittent periods in the drive control signal includes generating a measurement synch signal and performing the measurements in accordance with the measurement synch signal.

28. The method of claim 27, wherein performing the measurements in accordance with the measurement synch signal includes modifying one or more intermittent periods in the drive control signal.