Tuning of emitter with multiple LEDs to a single color bin

摘要

The color of an LED-based lamp can be tuned to a desired color or color temperature. The lamp can include two or more independently addressable groups of LEDs associated with different colors or color temperatures and a total-internal-reflection (TIR) color-mixing lens to produce light of a uniform color by mixing the light from the different groups of LEDs. The color of the output light is tuned by controllably dividing an input current among the groups of LEDs. Tuning can be performed once, e.g., during manufacture, and the lamp does not require active feedback components for maintaining color temperature.

主权项

1. A method for tuning a color produced by a lamp having a plurality of light emitting diodes (LEDs) including a first cool-white group of LEDs that produce cool white light with a color above a blackbody curve in a CIE color space, a second cool-white group of LEDs that produce cool white light with a color below a blackbody curve in a CIE color space, and a warm-white group of LEDs that produce warm white light, wherein a current applied to each group of LEDs is independently variable, the method comprising:
defining a target color in the CIE color space; establishing a first and second testing distributions of a total current among the groups of LEDs, wherein in each of the first and second testing distributions an equal current is supplied to each of the cool-white groups and a different current is supplied to the warm-white group; for each of the first and second testing distributions, measuring a color of light produced by the lamp; identifying a first tuned color intermediate between the color produced by the first testing distribution and the color produced by the second testing distribution that is closest to the target color; identifying, based on the measured colors, a warm-cool current distribution that produces the first tuned color, wherein the warm-cool current distribution provides a total cool-white current to the cool-white groups and a total warm-white current to the warm-white group; and determining a target distribution of the total cool-white current between the first and second cool-white groups of LEDs such that applying a first target portion of the total cool-white current to the first cool-white group of LEDs and a second target portion of the total cool-white current to the second cool-white group of LEDs minimizes a difference between the color of light produced by the lamp and the target color.