SELECTABLE CONTROL FOR HIGH INTENSITY LED ILLUMINATION SYSTEM TO MAINTAIN CONSTANT COLOR TEMPERATURE ON A LIT SURFACE

• US 20150173147A1
• Filed: 12/17/2014
• Published: 06/18/2015
• Est. Priority Date: 12/17/2013
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Ephesus Lighting, Inc. (Eaton Corporation PLC.)
• Inventors: Casper, Joseph R., Nolan, Christopher D., Witkowski, Joseph J., Shuster, Jeff R., Wilson, Brian M.
• Granted Patent: US 10,051,709 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: H05B 45/12 using optical feedback
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/22 using optical feedback
• CPC Class Codes: H05B 45/24 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/19 via wireless transmission
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

A lighting system includes a group of light emitting diode (LED) illumination devices, each of which includes a device driver. One or more sensors are configured to measure a characteristic of light received from the devices in an area of an environment that is illuminated by the devices. A controller detects when a value of the measured light characteristic received by a sensor deviates from a desired value. When this happens, the controller will cause the device drivers for each of the LED illumination devices to control LEDs in each illumination device so that the desired color temperature of light will be received at the location of the sensor while maintaining a substantially constant illuminance level at the location.

Claims

1. A lighting system, comprising:

a plurality of light emitting diode (LED) illumination devices, each of which comprises a first group of LEDs of a first color temperature and a second plurality of LEDs of a second color temperature;

a plurality of illumination device drivers, wherein each illumination device driver is configured to control a corresponding LED illumination device; and

a sensor that is configured to measure a characteristic of light received from the devices in an area of an environment that is illuminated by the devices;

a wireless transmitter that is connected to the sensor and configured to transmit measurements detected by the sensor; and

programming instructions that are configured to cause a processor to;

detect when a value of the measured light characteristic received by the sensor deviates from a desired value,

in response to detecting that the value of the measured light characteristic deviates from the desired value, generate commands to cause the device drivers for each of the LED illumination devices to control the first group of LEDs and the second group of LEDs in its corresponding illumination device so that the desired color temperature of light will be received at the location while maintaining a substantially constant illuminance level at the location.

2. The lighting system of claim 1, wherein the commands that cause the device drivers to control the first group of LEDs and the second group of LEDs in each illumination device so that the desired color temperature of light will be received at the location comprise instructions to increase the drive current delivered to the first group of LEDs and decrease the drive current delivered to the second group of LEDs in each illumination device.

3. The lighting system of claim 1, wherein the commands that cause the device drivers to control the first group of LEDs and the second group of LEDs so that the illuminance level remains substantially constant comprise at the location comprise commands to:

automatically reduce the brightness of one of the groups of LEDs by decreasing a width of voltage pulses applied to that group of LEDs or increasing spacing between voltage pulses applied to that group of LEDs; and

automatically increase the brightness of the other group of LEDs by increasing a width of voltage pulses applied to that group of LEDs or decreasing spacing between voltage pulses applied to that group of LEDs.

4. The lighting system of claim 1, wherein:

the sensor comprises a light intensity sensor; and

the programming instructions are configured so that;

when a value of measured light intensity exceeds a threshold, the device drivers will reduce the brightness of a group of the LEDs by decreasing a width of voltage pulses applied to the group of LEDs or increasing spacing between voltage pulses applied to the group of LEDs to maintain an illuminance level at the location within the threshold; and

when the value of measured light intensity is below the threshold, the device drivers will automatically increase the brightness of a group of the LEDs by increasing a width of voltage pulses applied to the group of LEDs or decreasing spacing between voltage pulses applied to the group of LEDs to maintain the illuminance level at the location within the threshold.

5. The lighting system of claim 1, wherein:

the sensor comprises a color temperature sensor; and

the programming instructions are configured so that when a value of color temperature detected by the sensor has moved above or below a threshold, the system will control drive currents delivered to the first group of LEDs and the second group of LEDs so that the light detected by the sensor at the location will exhibit a color temperature that is within the threshold.

6. The lighting system of claim 5, wherein the instructions to maintain the substantially constant illuminance level at the location comprise instructions to:

reduce the brightness of one of the groups of LEDs by decreasing a width of voltage pulses applied to that group of LEDs or increasing spacing between voltage pulses applied to that group of LEDs; and

increase the brightness of the other group of LEDs by increasing a width of voltage pulses applied to that group of LEDs or decreasing spacing between voltage pulses applied to that group of LEDs.

7. The lighting system of claim 1, wherein:

the sensor comprises a D_uv sensor; and

the programming instructions are configured so that when the value of D_uv detected by the sensor has moved above or below a threshold, the system will control drive currents delivered to the first group of LEDs and the second group of LEDs so that the light emitted by all of the LEDs will exhibit a D_uv that is within the threshold.

8. The lighting system of claim 7, wherein the instructions to maintain the substantially constant illuminance level at the location comprise instructions to:

reduce the brightness of one of the group of LEDs by decreasing a width of voltage pulses applied to that group of LEDs or increasing spacing between voltage pulses applied to that group of LEDs; and

increase the brightness of the other group of LEDs by increasing a width of voltage pulses applied to that group of LEDs or decreasing spacing between voltage pulses applied to that group of LEDs.

9. The lighting system of claim 1, wherein the illumination devices are positioned at various locations of an entertainment facility, and the sensors are located proximate to a playing surface or stage of the facility.

10. A method of controlling light directed to a surface, comprising:

operating a plurality of light emitting diode (LED) illumination devices to direct light to a surface of a facility, wherein each illumination device comprises;

a first group of LEDs of a first color temperature and a second plurality of LEDs of a second color temperature, and

a device driver configured to control the LED illumination device; and

by a controller;

receiving a value of a light characteristic detected by a sensor that is proximate the surface;

detecting when the value of the detected light characteristic deviates from a desired value,

in response to detecting that the received value deviates from the desired value, causing the device drivers for each of the LED illumination devices to control drive currents delivered to the first group of LEDs and the second group of LEDs of their illumination devices so that the desired color temperature of light will be directed to a location of the sensor while maintaining a substantially constant illuminance level at the location.

11. The method of claim 10, wherein causing the device drivers to control the first group of LEDs and the second group of LEDs in their illumination devices so that the desired color temperature of light will be received at the location comprises increasing the drive current delivered to the first group of LEDs and decreasing the drive current delivered to the second group of LEDs in each illumination device.

12. The method of claim 10, wherein causing the device drivers to control the first group of LEDs and the second group of LEDs so that the illuminance level remains substantially constant at the location comprises:

automatically reducing the brightness of one of the groups of LEDs by decreasing a width of voltage pulses applied to that group of LEDs or increasing spacing between voltage pulses applied to that group of LEDs; and

automatically increasing the brightness of the other group of LEDs by increasing a width of voltage pulses applied to that group of LEDs or decreasing spacing between voltage pulses applied to that group of LEDs.

13. The method system of claim 10, wherein:

the sensor comprises a light intensity sensor; and

detecting when the value of the detected light characteristic deviates from a desired value and causing the device drivers to control drive currents comprise;

when the value of measured light intensity exceeds a threshold, causing the device drivers to reduce the brightness of a group of the LEDs by decreasing a width of voltage pulses applied to the group of LEDs or increasing spacing between voltage pulses applied to the group of LEDs to maintain an illuminance level at the location within the desired range; and

when the value of measured light intensity is below the threshold, causing the device drivers to increase the brightness of a group of the LEDs by increasing a width of voltage pulses applied to the group of LEDs or decreasing spacing between voltage pulses applied to the group of LEDs to maintain the illuminance level at the location within the desired range.

14. The method of claim 10, wherein:

the sensor comprises a color temperature sensor; and

detecting when the value of the detected light characteristic deviates from a desired value and causing the device drivers to control drive currents comprise;

when a value of color temperature detected by the sensor has moved above or below a threshold, altering drive currents delivered to the first group of LEDs and the second group of LEDs so that the light detected by the sensor at the location will exhibit a color temperature that is within the threshold.

15. The method of claim 14, wherein maintaining the substantially constant illuminance level at the location comprises:

reducing the brightness of one of the groups of LEDs by decreasing a width of voltage pulses applied to that group of LEDs or increasing spacing between voltage pulses applied to that group of LEDs; and

increasing the brightness of the other group of LEDs by increasing a width of voltage pulses applied to that group of LEDs or decreasing spacing between voltage pulses applied to that group of LEDs.

16. The method of claim 10, wherein:

the sensor comprises a D_uv sensor; and

detecting when the value of the detected light characteristic deviates from a desired value and causing the device drivers to control drive currents comprises;

when the value of D_uv detected by the sensor has moved above or below a threshold, controlling drive currents delivered to the first group of LEDs and the second group of LEDs so that light received by the sensor exhibits a D_uv that is within the threshold.

17. The method of claim 16, wherein maintaining the substantially constant illuminance level at the location comprises:

reducing the brightness of one of the groups of LEDs by decreasing a width of voltage pulses applied to that group of LEDs or increasing spacing between voltage pulses applied to that group of LEDs; and

increasing the brightness of the other group of LEDs by increasing a width of voltage pulses applied to that group of LEDs or decreasing spacing between voltage pulses applied to that group of LEDs.

18. The method of claim 10, wherein the facility is an entertainment facility, and the sensors are located proximate to a playing surface or stage of the facility.