A color controlled light source and a method for controlling color generation in a light source

Abstract

This invention relates to a color controlled light source comprising a plurality of colored light elements; a detector for detecting the light output of the light source and generating a detection signal; and a color control unit for generating driving signals to said light elements on the basis of said detection signal and a predetermined target color point of the light output of the light source. In order to enable detection of contributions from individual light elements to the light output of the light source, the light source further comprises a modulator for individual signature modulation of the driving signal to each one of said light elements; and a corresponding demodulator for demodulation of said detection signal and generation of actual, i.e. measured, values of the output of the individual light elements. The color control unit determines nominal values of the light output of each light element for obtaining said target color point, and compares the actual values with the nominal values. If there is a difference, it adjusts the driving signals in order to minimize the difference.

Description

technical field [0001] The invention relates to solid state lighting and more particularly to a color controlled light source according to the preamble of claim 1 and a method of controlling color generation in a light source according to the preamble of claim 5 . Background technique [0002] In order to realize multicolor (eg different color temperature) light sources in solid state lighting, light emitting diodes emitting light of different colors are used in one device. These LEDs define subregions in the color space to indicate the gamut that can be achieved by all possible linear combinations. The desired intensity of colored light in the color spectrum of the color space can thus be controlled via the signal input of the individual LEDs. It should be noted that white light is also included in the term colored light. [0003] Unlike conventional light sources, colored LEDs will "color shift" as the light output changes from a predefined color point (color point) beg...

AI Technical Summary

Problems solved by technology

[0006] However, when the light detector detects the light output from the light source, it may be interfered by other light sources such as ambient sunlight and / or other colored LEDs

Therefore, the measured color intensity is often flawed and cannot alone represent the light output from the LEDs in the light source itself

Therefore, the feedback signal to the control device of the control loop is not suitable

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