Flexible LED lighting element
View Patent ↗A flexible LED lighting module includes a flexible housing and flexible PCB to which LED units are mounted. An encapsulant fills a channel of the flexible housing and has a same or similar optical refractive index value as is used in the LED unit to hold phosphorous particles used for coloring of the LED. Use of the encapsulant changes the color of the light ultimately emitted from the flexible LED lighting module, and this factor is corrected for in calibration processes associated with the flexible LED lighting module.
1. A method for calibrating a flexible LED lighting element comprising at least first, second, and third-color LEDs, and white LEDs, as well as an LED unit encapsulant that covers the LEDs and contains embedded phosphor particles of different colors, comprising:
providing a flexible LED lighting element comprising at least first, second, and third-color LEDs, and white LEDs, as well as an LED unit encapsulant that covers the LEDs and contains embedded phosphor particles of different colors;
a) defining a target color on a color map to calibrate;
b) selecting initial calibration coefficients associated with the target color, wherein one of the initial calibration coefficients is based on predetermined properties of the LED unit encapsulent and attributes of the white LEDs;
c) storing: 1) the initial, or 2) updated calibration coefficients in a non-volatile memory of the light unit;
d) controlling the light unit with a controller to drive the LEDs to attempt to emit the target color, producing an attempted color, utilizing one of the initial and updated calibration coefficients;
e) measuring the attempted color to determine if it matches the target color within a predefined tolerance;
f) if the attempted color matches the target color, then terminating the method;
g) if the attempted color does not match the target color, then performing the following;
h. 1) selecting a first color component;
i. 1) adapting at least one calibration coefficient associated with the selected first color component by a first color component first amount;
j. 1) performing (c)-(g) again;
h. 2) selecting a second color component that is different from the first color component;
i. 2) adapting at least one calibration coefficient associated with the selected second color component by a second color component first amount;
j.2) performing (c)-(g) again;
h. 3) selecting the first color component;
i. 3) adapting the at least one calibration coefficient associated with the selected first color component by a first color component second amount that is smaller than the first color component first amount and avoids an overshoot of the target color;
j. 3) performing (c)-(g) again;
h. 4) selecting the second color component;
i. 4) adapting the at least one calibration coefficient associated with the selected second color component by a second color component second amount that is smaller than the second color component first amount and avoids an overshoot of the target color;
j. 4) performing (c)-(g) again.
2. The method of claim 1 , wherein the attributes of the white LEDs include x and y chromaticity values, flux values, and spectral content values.
3. The method of claim 1 , wherein the white LEDs are warm white LEDs and the one of the initial calibration coefficient incorporates a color shift of 900° K.
4. The method of claim 1 , wherein the white LEDs are cool white LEDs and the one of the initial calibration coefficient incorporates a color shift of 1200° K.