Control system for an illumination device incorporating discrete light sources

• US 20050062446A1
• Filed: 07/22/2004
• Published: 03/24/2005
• Est. Priority Date: 07/23/2003
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: TIR Systems Limited (Koninklijke Philips N.V.)
• Inventors: Ashdown, Ian
• Granted Patent: US 7,140,752 B2
• Time in Patent Office: Days
• US Class Current: 315/324
• 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 colour control of the illumination produced by the system. The illumination system comprises a plurality of light-emitting elements which create illumination at a number of different wavelengths wherein the colour that can be produced by the illumination system is based on the colour gamut defined by the colours of the individual light-emitting elements being blended. The system further includes at least one detecting device in order to collect information relating to the illumination being created by the plurality of light-emitting elements, wherein this information can relate to the luminous flux being produced at the various wavelengths. A computing system is integrated into the illumination system, wherein this computing system provides a means for receiving the information from the at least one detecting device and determines control parameters based on a multivariate function having a solution defining the hyperplane representing constant luminous intensity and chroma. Under these conditions the computing system can essentially linearise the information from the detecting device, thereby determining a number of control parameters from the input information, for transmission to a controller. The controller integrated into the system subsequently determines the control signals to be sent to the light-emitting elements in order to control the illumination produced thereby. In this manner, the illumination system according to the present invention can detect the produced illumination and dynamically alter the produced colour or intensity, for example, based on the collected information and the desired illumination result.

Claims

1. An illumination system comprising:

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

b) at least one detecting device for providing information regarding the illumination being created by the light-emitting elements;

c) a computing system for receiving the information from the at least one detecting device and based on a predetermined set of parameters, determining a plurality of control parameters;

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 elements in order to control the illumination being created; and

e) a power source for providing power to the illumination system.

2. The illumination system according to claim 1, wherein the predetermined set of parameters is defined by a multivariate function having a solution defining a hyperplane representing constant chromaticity.

3. The illumination system according to claim 1, wherein the at least one detecting device is capable of collecting information representing characteristics selected from the group comprising luminous and spectral radiant flux of the illumination, junction temperature of at least one of the plurality of light-emitting elements, desired luminous intensity, correlated colour temperature and ambient light.

4. The illumination system according to claim 1, wherein the at least one detecting device is a photometric sensor or a colourmetric sensor.

5. The illumination system according to claim 1, wherein the computing device is a microcontroller.

6. The illumination system according to claim 1, wherein a neural network is integrated into the computing system.

7. The illumination system according to claim 6, wherein the neural network is a radial basis function.

8. The illumination system according to claim 6, wherein the neural network is a generalised radial basis function.

9. The illumination system according to claim 1, wherein the controller is a proportional integral-derivative controller.

10. The illumination system according to claim 1, wherein controller functionality is integrated into the computing system.

11. The illumination system according to claim 1, wherein the plurality of light-emitting elements are arranged in one or more arrays.

12. The illumination system according to claim 11, wherein each of the one or more arrays are individually controlled by the controller.

13. The illumination system according to claim 1, wherein the plurality of light emitting elements are individually controlled by the controller.