Calibration method for LED lighting systems

摘要

A method of operating a lighting fixture comprising a plurality of discrete illumination sources of distinguishably different color coordinates comprises determining target color coordinates and luminous flux at which to operate the lighting fixture, determining input electrical power values for each of the plurality of discrete illumination sources that substantially produce the target color coordinates and luminous flux by referencing a calibration data lookup table having calibration data based on measurements of the plurality of discrete illumination sources, determining a color mixing zone defined by three distinguishably different color coordinates of the plurality of discrete illumination sources within which the target color coordinates lie according to the calibration data, determining luminous flux ratios for each of the plurality of discrete illumination sources having one of the three distinguishably different color coordinates defining the color mixing zone that substantially produces the target color coordinates, and determining input electrical power levels for each of the plurality of discrete illumination sources that generate the determined luminous flux ratios.

主权项

1. A method of calibrating a lighting fixture comprising a plurality of discrete illumination sources of distinguishably different color coordinates, the method comprising:
measuring and recording a color coordinate (Cmr,g,b) for each of the plurality of discrete illumination sources separately while each of the illumination sources is operated at a specific drive level; measuring and recording an operating temperature (T0) along with the recorded color coordinates; inputting a desired target color set point (CT) and luminous flux (φT); obtaining operating color coordinates (C1) and luminous flux (φ1) of each LED at the drive level duty cycle (d1) using at least one of an iterative method, a color shift measurement method, and a direct measurement method; operating the lighting fixture at the obtained operating color coordinates (C1) and luminous flux (φ1) of each LED at the drive level duty cycle d1, and measuring the overall measured color coordinates (CmT) and luminous flux (φmT) along with the temperature (T0); determining if the distance between the measured color coordinates (CmT) and the operating color coordinates (C1) are less than a predefined value;
if not, then computing a computed flux (φc) based on the measured color coordinates (CmT) and the measured luminous flux (φmT), and adjusting the operating luminous flux (φ1) and returning to the operating of the light fixture at the adjusted operating luminous flux (φ1);if so, then measuring the operating temperature T0) and recording the operating temperature with the operating color coordinates (C1) and the adjusted operating luminous flux (φ1); estimating an operating luminous flux (φn) for color points with a same color coordinate (Cn) but different flux level; and performing a validation that ensures the lighting fixture produces desired color set points when the fixture is controlled using compensation methods that use calibration data derived from the above procedure.