Tuning of emitter with multiple LEDs to a single color bin
First Claim
1. A method for tuning a color produced by a lamp having a plurality of light emitting diodes (LEDs) including a plurality of groups of LEDs wherein each group of LEDs produces light having a different color and wherein a current applied to each group of LEDs is independently variable, the method comprising:
- establishing at least two different testing distributions of a total current among the groups of LEDs;
for each of the different testing distributions of the total current, measuring a color of light produced by the lamp;
defining a target color; and
determining a desired distribution of the total current based at least in part on the measured colors and a proportionality constant that linearly relates a unit of change in the distribution of the total current to an amount of change in the color of light produced by the lamp, wherein the desired distribution of the total current produces light having the target color.
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Accused Products
Abstract
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.
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Citations
21 Claims
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1. A method for tuning a color produced by a lamp having a plurality of light emitting diodes (LEDs) including a plurality of groups of LEDs wherein each group of LEDs produces light having a different color and wherein a current applied to each group of LEDs is independently variable, the method comprising:
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establishing at least two different testing distributions of a total current among the groups of LEDs; for each of the different testing distributions of the total current, measuring a color of light produced by the lamp; defining a target color; and determining a desired distribution of the total current based at least in part on the measured colors and a proportionality constant that linearly relates a unit of change in the distribution of the total current to an amount of change in the color of light produced by the lamp, wherein the desired distribution of the total current produces light having the target color. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for controlling a color produced by an emitter having a plurality of light-emitting diodes (LEDs) including a plurality of warm white LEDs and a plurality of cool white LEDs, the method comprising:
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measuring a first value for a color property of the emitter under a first operating condition in which a maximum current is supplied to the warm white LEDs and a minimum current is supplied to the cool white LEDs; measuring a second value for the color property of the emitter under a second operating condition in which the maximum current is supplied to the cool white LEDs and the minimum current is supplied to the cool white LEDs; measuring a third value for the color property of the emitter under a third operating condition in which approximately half of a total current is delivered to the warm white LEDs and the rest of the total current is delivered to the cool white LEDs, wherein the total current is equal to a sum of the maximum current and the minimum current; calculating a first operating current to be supplied to the warm white LEDs and a second operating current to be supplied to the cool white LEDs, wherein the calculation is based on the measured first, second, and third values of the color property;
a target value of the color property; and
a proportionality constant that linearly relates a unit of change in a difference between a current delivered to the warm white LEDs and a current delivered to the cool white LEDs to an amount of change in the color property; andsetting a current controller coupled to the emitter such that when the first operating current is supplied to the warm white LEDs, the second operating current is supplied to the cool white LEDs. - View Dependent Claims (14)
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15. A method for controlling a color produced by a lamp having a plurality of light-emitting diodes (LEDs) including a plurality of warm white LEDs and a plurality of cool white LEDs, the method comprising:
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measuring a first value of a color property of the lamp while supplying a total current (ITOT) to the warm white LEDs and no current to the cool white LEDs; measuring a second value of the color property of the lamp while supplying the total current ITOT to the cool white LEDs and no current to the warm white LEDs; measuring a third value of the color property of the lamp while supplying half the total current ITOT to the warm white LEDs and half the total current ITOT to the cool white LEDs; calculating a first operating current to be supplied to the warm white LEDs and a second operating current to be supplied to the cool white LEDs to achieve a target value of the color property, wherein the total current ITOT is equal to a sum of the first operating current and the second operating current, and wherein the determination of the first and second operating current is based on the measured first, second and third values of the color property and a proportionality constant that linearly relates a unit of change in a difference between the first and second operating currents to an amount of change in the color property; and configuring a control circuit of the lamp such that when the first operating current is supplied to the warm white LEDs, the second operating current is supplied to the cool white LEDs. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification