METHOD AND APPARATUS FOR PROVIDING A PASSIVE COLOR CONTROL SCHEME USING BLUE AND RED EMITTERS
First Claim
1. A light-emitting device, comprising:
- a string of first light-emitting diodes (“
LEDs”
) having multiple junctions able to convert electrical energy to optical light having a range of wavelengths from 400 to 500 nanometer (“
nm”
), wherein the first LEDs are connected in series; and
a string of second LEDs having multiple junctions configured to convert electrical energy to optical light having a range of wavelengths from 580 to 700 nm, wherein the second LEDs are connected in series, wherein the string of first LEDs and the string of second LEDs are coupled in parallel allowing current redistribution in response to temperature fluctuations.
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Accused Products
Abstract
A lighting device capable of generating warm or neutral white light using blue light-emitting diodes (“LEDs”), red LEDs, and/or luminescent material that responds to blue LED emission is disclosed. The lighting device includes multiple first solid-state light-emitting structures (“SLSs”), second SLSs, and balancing resistor element. The first SLS such as a string of blue LED dies connected in series is able to convert electrical energy to blue optical light, which is partially turned into longer wavelength emission by the luminescent material. The second SLS such as a red LED die is configured to convert electrical energy to red optical light, wherein the second SLSs are connected in series. While the first SLSs and second SLSs are coupled in parallel, the balancing resistor element provides load balance for current redistribution between the first and second SLSs in response to fluctuation of operating temperature.
10 Citations
20 Claims
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1. A light-emitting device, comprising:
-
a string of first light-emitting diodes (“
LEDs”
) having multiple junctions able to convert electrical energy to optical light having a range of wavelengths from 400 to 500 nanometer (“
nm”
), wherein the first LEDs are connected in series; anda string of second LEDs having multiple junctions configured to convert electrical energy to optical light having a range of wavelengths from 580 to 700 nm, wherein the second LEDs are connected in series, wherein the string of first LEDs and the string of second LEDs are coupled in parallel allowing current redistribution in response to temperature fluctuations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A solid-state lighting device, comprising:
-
a string of first light-emitting diodes (“
LEDs”
) having multiple junctions able to convert electrical energy to bluish optical light;a string of second LEDs having multiple junctions configured to convert electrical energy to reddish light; and a red light flux balancing element coupled to the string of second LEDs in series and capable of redistributing current passing through the string of second LEDs to compensate differential voltage across the string of second LEDs due to fluctuation of junction temperature of the string of second LEDs. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A lighting device, comprising:
-
a string of blue light-emitting diodes (“
LEDs”
) having multiple junctions able to convert electrical energy to blue light, wherein the blue LEDs are connected in series; anda string of red LEDs having multiple junctions configured to convert electrical energy to red light, wherein the red LEDs are connected in series, wherein the string of blue LEDs and the string of red LEDs are coupled in series; and a shunt controller coupled to the string of red LEDs and able to activate at least one shunt red LED to compensate loss of red flux in response to temperature fluctuation affecting differential voltage drops across the string of blue LEDs and the string of red LEDs. - View Dependent Claims (17, 18, 19, 20)
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Specification