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Method and arrangement for simulation of high-quality daylight spectra

  • US 20110062873A1
  • Filed: 09/08/2010
  • Published: 03/17/2011
  • Est. Priority Date: 09/10/2009
  • Status: Active Grant
First Claim
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1. Method for simulation of high-quality daylight or artificial light spectra at color temperatures in the range of 2,700 K to 10,000 K, particularly for the purpose of lighting matching surfaces in comparative color matching of prints, textiles, and similar products, having defined, predetermined color characteristics,comprising the following method steps:

  • a) producing light by means of a plurality of LEDs disposed in groups, wherebyeach group is formed from LEDs positioned in compact manner next to one another, andthe LEDs within each group emit light at different wavelengths, so thatlight of a specific spectrum to be simulated is emitted by each group,b) measuring the spectra of the light emitted by each individual LED at different predetermined working temperatures,c) calculating the tristimulus values XYZ (CIE1931 2°

    ) for each measured temperature range, preferably with linear interpolation of the intermediate values,d) storing the calculated tristimulus values in memory, with assignment to the working temperatures and the PWM values as color characteristics for each LED,e) actuating the LEDs at the working temperatures and PWM values selected from the memory content, as a function of the spectrum to be simulated,f) during a predetermined cycle frequency, constantly repeatedly measuring the working temperature of each individual LED chip and comparing it with the tristimulus values stored in memory with regard to working temperature,g) in case of agreement of the current measurement result with the stored value;

    continuing to actuate the LED in question at the previous values for the working temperature,h) in case of deviation of the current working temperature from the stored value;

    determining the tristimulus values that belong to the current working temperature and/or a suitable PWM value from the memory content assigned to this LED.

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