Control system for an illumination device incorporating discrete light sources

• US 7,687,753 B2
• Filed: 10/13/2006
• Issued: 03/30/2010
• Est. Priority Date: 07/23/2003
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Ashdown, Ian
• Primary Examiner(s): Sohn; Seung C
• Application Number:
  US11/549,593
• Publication Number:
  US 20080224024A1
• Time in Patent Office: 1,264 Days
• Field of Search: 250/205, 362/276, 315/316
• US Class Current: 250/205
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/22 using optical feedback
• CPC Class Codes: H05B 45/28 using temperature feedback
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

The present invention provides an illumination system enabling dynamic color control of the illumination produced by the system. The illumination system comprises light-emitting elements for producing illumination, and at least one detecting device which collects information relating to the illumination, which is inherently non-linear. The illumination system also integrates a computing system which receives, the information from the at least one detecting device and linearises this information using a multivariate function having a solution defining a hyperplane representing constant chromaticity for a given luminous intensity, and then determines a number of control parameters based on the information. The illumination system also integrates a controller for receiving the control parameters from the computing system and determining the control signals to be sent to the light-emitting elements in order to dynamically alter the characteristics of the illumination based on the collected information and the desired illumination result.

Claims

1. An illumination system comprising:

a) a plurality of light-emitting diodes for providing illumination having a variety of wavelengths;

b) one or more detecting devices for providing information regarding the illumination being created by the light-emitting diodes;

c) a computing system for receiving the information from the one or more detecting devices and based on a predetermined set of parameters, determining a plurality of control parameters, said predetermined set of parameters defined by a multivariate function having a solution defining a hyperplane representing constant chromaticity for a given luminous intensity; and

d) a controller for receiving the plurality of control parameters and determining a set of control signals, wherein said control signals are sent to the light-emitting diodes in order to control the illumination being created,

wherein at least one of the one of the one or more detecting devices is configured to detect junction temperature of the light-emitting diodes.

2. The illumination system according to claim 1, wherein at least one detecting device is a colour sensor having tricolour sensing capabilities.

3. The illumination system according to claim 2, wherein the colour sensor is configured as a programmable gain light-to-frequency converter with filtered red, green and blue channels for colourmetric measurements.

4. The illumination system according to claim 1, wherein at least one detecting device is configured to detect correlated colour temperature of the illumination.

5. The illumination system according to claim 1, wherein at least one detecting device is configured to enable input of user requests.

6. The illumination system according to claim 5, wherein user requests provide an indication of desired chromaticity in a direction orthogonal to the blackbody locus to effect a desired change in tint of nominal white light illumination while maintaining a predetermined correlated colour temperature of the illumination.

7. The illumination system according to claim 1, wherein at least one detecting device is a colourimeter configured to monitor intensity and spectral distribution of ambient illumination.

8. The illumination system according to claim 7, wherein ambient illumination is a combination of daylight and luminous flux emitted by the illumination system.

9. The illumination system according to claim 1, wherein one or more of the plurality of light-emitting diodes is a semiconductor light-emitting diode which emits visible light.

10. The illumination system according to claim 1, wherein one or more of the plurality of light-emitting diodes is an organic light-emitting diode which emits visible light.

11. The illumination system according to claim 10, wherein one or more of the plurality of light-emitting diodes is a semiconductor light-emitting diode which emits visible light.

12. The illumination system according to claim 1, wherein the illumination system has an illumination colour gamut, the illumination colour gamut defined by individual illumination colour generated by each of the plurality of light-emitting diodes.

13. The illumination system according to claim 1, wherein individual illumination colour generated by each of the plurality of light-emitting diodes are centered around wavelengths of red, green or blue.

14. The illumination system according to claim 1, wherein the computing system is an architectural dimming control system.

15. The illumination system according to claim 1, wherein the computing system is configured to maintain constant chromaticity during intensity adjustment of the illumination generated by the illumination system.

19. The illumination system according to claim 1, further comprising a power source for providing power to the illumination system.

16. An illumination system comprising:

a plurality of light-emitting elements for providing illumination having a variety of wavelengths;

one or more detecting devices for providing information regarding the illumination being created by the light-emitting elements;

a computing system for receiving the information from the one or more detecting devices and based on a predetermined set of parameters, determining a plurality of control parameters, said predetermined set of parameters defined by a multivariate function having a solution defining a hyperplane representing constant chromaticity for a given luminous intensity, the computing system including a neural network trainable using a predetermined set of inputs and desired control parameters resulting therefrom; and

a controller for receiving the plurality of control parameters and determining a set of control signals, wherein said control signals are sent to the light-emitting elements in order to control the illumination being created.

17. The illumination system according to claim 16, wherein the neural network is configured to perform non-linear colour mapping from three different colour channels of a colour sensor to control parameters for four different colours of light-emitting elements.

18. The illumination system according to claim 16, wherein the neural network is configured to follow a user-defined correlation with daylight illumination, said daylight illumination having an intensity and correlated colour temperature.

20. The illumination system according to claim 16, further comprising a power source for providing power to the illumination system.