System Having Independent Control of Circadian Response and Color Temperature

Abstract

Methods and systems as described herein may be used for independently controlling the color temperature, intensity, and/or circadian response (CR) of one or more light sources (e.g., discrete-spectrum light sources) to adjust one or more color temperature, intensity, and circadian metrics in a space. For example, a light fixture may have four controllable light sources, a warm CR boost, cool CR boost, warm non-boost CR and a cool non-boost CR to independently control intensity, color temperature, and CR outputs.

What is claimed: 
     
         1 . A lighting fixture configured to produce a cumulative light output comprising a color temperature, an intensity, and a circadian response, the light fixture comprising:
 a first light source configured to emit light having a first color temperature;   a second light source configured to emit lighting having a second color temperature;   wherein the first and second color temperatures comprise a substantially same color temperature;   wherein the light emitted by the first light source is configured to produce a higher spectral power distribution over a range of wavelengths in a first region of the visible light spectrum than the light emitted by the second light source;   a communication circuit configured to receive commands; and   a control circuit coupled to the communication circuit, the control circuit configured to:
 receive, via the communication circuit, a command to adjust a circadian response of the cumulative light output, wherein the circadian response comprises a value that indicates a sum of intensities of light sources that are configured to produce a higher spectral power distribution over the range of wavelengths with respect to a cumulative light intensity of the fixture; 
 based on the command, determine a respective intensity of the first light source and the second light source; and 
 control the first and second light sources to the determined respective intensities to produce the adjusted circadian response of the cumulative light output. 
   
     
     
         2 . The lighting fixture of  claim 1 , further comprising:
 a third light source configured to emit light having a third color temperature; and   a fourth light source configured to emit light having a fourth color temperature;   wherein the third and fourth color temperatures comprise a second substantially same color temperature different from the substantially same color temperature of the first and second light sources;   wherein the third light source is configured to produce a higher spectral power distribution over the range of wavelengths in the first region of the visible light spectrum than the light emitted by the fourth light source; and   wherein the control circuit is further configured to, based on the command to adjust the circadian response, determine a respective intensity of the third light source and the fourth light source; and
 control the intensity of the third and fourth light sources to produce the circadian response of the cumulative light output according to the received command. 
   
     
     
         3 . The lighting fixture of  claim 2 , wherein the substantially same color temperature of the first and second light sources comprises a warm color temperature in the range of 1800K-3000K. 
     
     
         4 . The lighting fixture of  claim 3 , wherein the second substantially same color temperature comprises a cool color temperature in the range of 3500K-8000K. 
     
     
         5 . The lighting fixture of  claim 4 , wherein the first region of the visible light spectrum comprises a blue region of the visible light spectrum. 
     
     
         6 . The lighting fixture of  claim 5 , wherein the range of wavelengths is approximately 425 nanometers to 525 nanometers. 
     
     
         7 . The lighting fixture of  claim 1 , wherein the first light source comprises a blue LED and the second light source comprises a purple LED. 
     
     
         8 . The lighting fixture of  claim 7 , wherein the blue LED has a primary emission peak between approximately 425 nanometers to 525 nanometers, further wherein the purple LED has a primary emission peak less than 425 nanometers. 
     
     
         9 . The lighting fixture of  claim 2 , wherein the third light source comprises a blue LED and the fourth light source comprises a purple LED. 
     
     
         10 . The lighting fixture of  claim 9 , wherein the blue LED has a primary emission peak between approximately 425 nanometers to 525 nanometers, further wherein the purple LED has a primary emission peak less than 425 nanometers. 
     
     
         11 . The lighting fixture of  claim 10 , wherein the blue LED has a primary emission peak between approximately 440 nanometers to 490 nanometers, further wherein the purple LED has a primary emission peak less than 425 nanometers. 
     
     
         12 . The lighting fixture of  claim 1 , wherein the first color temperature and the second color temperature have corresponding chromaticities within a one-step MacAdam ellipse of each other. 
     
     
         13 . The lighting fixture of  claim 2 , wherein the second color temperature and the third color temperature have corresponding chromaticities within a one-step MacAdam ellipse of each other. 
     
     
         14 . The lighting fixture of  claim 1 , wherein the control circuit is further configured to maintain the intensity and the color temperature of the cumulative light output when the circadian response is adjusted in response to the received command. 
     
     
         15 . The lighting fixture of  claim 2 , wherein the control circuit is further configured to maintain the intensity and the color temperature of the cumulative light output when the circadian response is adjusted. 
     
     
         16 . The lighting fixture of  claim 2 , wherein the control circuit is further configured to:
 receive a second command comprising an intensity, a CCT, and a circadian response;   determine the intensities of the first, second, third and fourth light sources based on the received intensity, CCT, and circadian response of the second command; and   control the intensities of the first, second, third and fourth light sources to produce the intensity, CCT, and circadian of the cumulative light output according to the received command; and   wherein the intensity of the first light source as a percentage of the first and second light sources is equal to the intensity of the third light source as a percentage of the third and fourth light sources.   
     
     
         17 . A system for controlling a cumulative light output, the system comprising:
 a first light emitting diode (LED) having a primary emission peak between approximately 425 nanometers to 525 nanometers and configured to emit light having a first color temperature;   a second LED having a primary emission peak less than 425 nanometers and configured to emit lighting having a second color temperature;   wherein the first and second color temperatures comprise a first substantially same color temperature in the range of 1800K-3000K;   a third LED having a primary emission peak between approximately 425 nanometers to 525 nanometers and configured to emit light having a third color temperature; and   a fourth LED having a primary emission peak less than 425 nanometers and configured to emit light having a fourth color temperature;   wherein the third and fourth color temperatures comprise a second substantially same color temperature in the range of 3500K-8000K; and   wherein the light emitted by the first and third LEDs is configured to produce a higher spectral power distribution over a range of wavelengths in a first region of the visible light spectrum than the light emitted by the second and fourth LEDs.   
     
     
         18 . The system of  claim 17 , wherein the first, second, third, and fourth light sources are housed within a lighting fixture. 
     
     
         19 . The lighting fixture of  claim 18 , wherein the first color temperature and the second color temperature have corresponding chromaticities within a one-step MacAdam ellipse of each other; and
 wherein the second color temperature and the third color temperature have corresponding chromaticities within a one-step MacAdam ellipse of each other.   
     
     
         20 . The system of  claim 19 , further comprising:
 an input device; and   a system controller comprising a communication circuit for transmitting and receiving commands, wherein the system controller is configured to:
 receive, via the communication circuit, a command from the input device, to adjust circadian response, wherein the circadian response comprises a value that indicates a sum of respective intensities of the first and second LEDs with respect to a sum of respective intensities of the first, second, third, and fourth LEDs representing the cumulative light intensity of the fixture; and 
 based on the received command, transmit, via the communication circuit, a second command to adjust circadian response to the lighting fixture. 
   
     
     
         21 . The system of  claim 20 , wherein the lighting fixture further comprises:
 a first communication circuit configured to receive commands from the system controller; and   a control circuit coupled to the communication circuit and operably coupled to the first, second, third and fourth light sources, wherein the control circuit is configured to:
 receive, via the first communication circuit, the second command to adjust circadian response of the cumulative light output, 
 based on the command, determine a respective intensity of the first, second, third, and fourth light sources; and 
 control the first, second, third and fourth light sources to the determined respective intensities to produce the adjusted circadian response of the cumulative light output.