Methods and apparatus for generating white light

Abstract

Methods and apparatus for generating essentially white light. In one example, a white light generating apparatus comprises at least one first white LED characterized by a first spectrum, and at least one second white LED characterized by a second spectrum, wherein the first spectrum is substantially different than the second spectrum.

1 . An apparatus for generating essentially white light, comprising: 
 at least one first white LED characterized by a first spectrum having a first color temperature, the at least one first white LED including a first phosphor, the at least one first white LED generating at least one first wavelength that is converted by the first phosphor to provide the first spectrum; and    at least one second white LED characterized by a second spectrum having a second color temperature, the at least one second white LED including a second phosphor, the at least one second white LED generating at least one second wavelength that is converted by the second phosphor to provide the second spectrum, wherein the first color temperature and the second color temperature are perceivably different to a human observer.    
   
   
       2 . The apparatus of  claim 1 , further comprising at least one optical filter configured to selectively transmit a portion of light emitted from at least one of the first and second white LEDs.  
   
   
       3 . The apparatus of  claim 2 , wherein the at least one optical filter is a high pass filter.  
   
   
       4 . The apparatus of  claim 2 , wherein the at least one optical filter comprises a plurality of optical filters, each of the plurality of optical filters being configured to selectively transmit a portion of the light emitted from at least one of the first and second white LEDs.  
   
   
       5 . The apparatus of  claim 4 , wherein the selectively transmitted portion of the light emitted from the at least one of the first and second LEDs includes at least a portion of the Planckian locus.  
   
   
       6 . The apparatus of  claim 4 , wherein at least one of the plurality of filters is a yellow filter.  
   
   
       7 . The apparatus of  claim 2 , wherein the first white LED has a color temperature of approximately 20,000 Kelvin, and the second white LED has a color temperature of approximately 5,750 Kelvin.  
   
   
       8 . The apparatus of  claim 2 , wherein: 
 the at least one optical filter comprises a plurality of optical filters;    wherein at least a first one of the plurality of optical filters is adapted to transmit a portion of the light corresponding to a color temperature of approximately 2,300 Kelvin; and    wherein at least a second one of the plurality of optical filters is adapted to transmit a portion of the light corresponding to a color temperature of approximately 4,500 Kelvin.    
   
   
       9 . The apparatus of  claim 1 , wherein the first color temperature differs from the second color temperature by an amount that exceeds a minimum color temperature discrimination of the human eye over a range of color temperatures from 700 Kelvin to 20,000 Kelvin.  
   
   
       10 . The apparatus of  claim 9 , wherein the first white LED has a color temperature of approximately 2,300 Kelvin, and the second white LED has a color temperature of approximately 4,500 Kelvin.  
   
   
       11 . The apparatus of  claim 1 , further comprising a mounting configured to approximate an appearance of a fluorescent tube.  
   
   
       12 . The apparatus of  claim 11 , wherein the at least one first white LED and the at least one second white LED are configured in a substantially linear arrangement.  
   
   
       13 . The apparatus of  claim 1 , further comprising at least one controller adapted to pulse width modulate at least one of the plurality of first and second white LEDs.  
   
   
       14 . The apparatus of  claim 1 , further comprising at least one third LED having a third spectrum different that the first spectrum and the second spectrum.  
   
   
       15 . The apparatus of  claim 14 , wherein the at least one third LED includes at least one third white LED.  
   
   
       16 . The apparatus of  claim 14 , wherein the at least one third LED includes at least one amber LED.  
   
   
       17 . The apparatus of  claim 14 , further comprising: 
 at least one fourth LED having a fourth spectrum; and    at least one fifth LED having a fifth spectrum,    wherein the first, second, third, fourth and fifth spectra are respectively different.    
   
   
       18 . The apparatus of  claim 17 , further comprising: 
 at least one sixth LED having a sixth spectrum; and    at least one seventh LED having a seventh spectrum,    wherein the first, second, third, fourth, fifth, sixth and seventh spectra are respectively different.    
   
   
       19 . The apparatus of  claim 1 , wherein a first quantity of the at least one first white LED is different than a second quantity of the at least one second white LED.  
   
   
       20 . The apparatus of  claim 1 , further comprising at least one controller adapted to independently control a first intensity of first radiation emitted from the at least one first white LED and a second intensity of second radiation emitted from the at least one second white LED.  
   
   
       21 . The apparatus of  claim 20 , wherein the at least one first white LED comprises a plurality of first white LEDs and the at least one second white LED comprises a plurality of second white LEDs, and wherein the at least one controller is configured to generate a first control signal to control all of the first white LEDs substantially identically to one another, and a second control signal to control all of the second white LEDs substantially identically to one another.  
   
   
       22 . The apparatus of  claim 20 , further comprising at least one power connection coupled to the at least one controller, the at least one power connection configured to engage mechanically and electrically with a conventional light socket.  
   
   
       23 . The apparatus of  claim 22 , wherein the at least one power connection includes an Edison screw-type power connection.  
   
   
       24 . The apparatus of  claim 22 , wherein the at least one power connection includes a fluorescent-type power connection.  
   
   
       25 . The apparatus of  claim 22 , wherein the at least one power connection includes a halogen MR-16-type power connection.  
   
   
       26 . The apparatus of  claim 22 , further comprising at least one of a housing and a mounting for the at least one first white LED and the at least one second white LED, wherein the at least one of the housing and the mounting is configured to resemble at least one type of conventional light bulb.  
   
   
       27 . The apparatus of  claim 26 , wherein the at least one of the housing and the mounting is configured to resemble an Edison-mount light bulb housing.  
   
   
       28 . The apparatus of  claim 26 , wherein the at least one of the housing and the mounting is configured to resemble a fluorescent light bulb housing.  
   
   
       29 . The apparatus of  claim 26 , wherein the at least one of the housing and the mounting is configured to resemble a halogen MR-16-type light bulb housing.  
   
   
       30 . The apparatus of  claim 20 , wherein the at least one controller is configured to independently control the at least one first white LED and the at least one second white LED so as to controllably vary a color temperature of the essentially white light generated by the apparatus.  
   
   
       31 . The apparatus of  claim 30 , further comprising at least one user interface coupled to the at least one controller and configured to facilitate an adjustment of the color temperature of the essentially white light generated by the apparatus.  
   
   
       32 . The apparatus of  claim 30 , further comprising at least one sensor coupled to the at least one controller and configured to generate at least one control signal in response to at least one detectable condition, wherein the at least one controller is configured to control the color temperature of the essentially white light generated by the apparatus in response to the at least one control signal.  
   
   
       33 . The apparatus of  claim 30 , further comprising at least one of a receiver and a transmitter coupled to the at least one controller and configured to communicate at least one control signal to or from the apparatus.  
   
   
       34 . The apparatus of  claim 30 , wherein the at least one controller is configured to independently control the at least one first white LED and the at least one second white LED using a pulse width modulation (PWM) technique.  
   
   
       35 . The apparatus of  claim 30 , wherein the at least one controller is configured as an addressable controller capable of receiving at least one network signal including at least first lighting information relating to the color temperature of the essentially white light generated by the apparatus.  
   
   
       36 . The apparatus of  claim 35 , wherein the at least one network signal includes address information and lighting information for a plurality of apparatus, and wherein the at least one controller is configured to process the at least one network signal based on at least the address information in the at least one network signal to recover the first lighting information.  
   
   
       37 . The apparatus of  claim 35 , wherein the at least one network signal is formatted using a DMX protocol, and wherein the at least one controller is configured to independently control the first intensity of the first radiation emitted from the at least one first LED and the second intensity of the second radiation emitted from the at least one second white LED based at least in part on the DMX protocol.  
   
   
       38 . A method for generating essentially white light, comprising: 
 generating first radiation from at least one first white LED, the first radiation characterized by a first spectrum having a first color temperature, the at least one first white LED including a first phosphor, the at least one first white LED generating at least one first wavelength that is converted by the first phosphor to provide the first spectrum;    generating second radiation from at least one second white LED, the second radiation characterized by a second spectrum having a second color temperature, the at least one second white LED including a second phosphor, the at least one second white LED generating at least one second wavelength that is converted by the second phosphor to provide the second spectrum, wherein the first color temperature and the second color temperature are perceivably different to a human observer; and    combining the first radiation and the second radiation to form a light output.    
   
   
       39 . The method of  claim 38 , wherein the first color temperature differs from the second color temperature by an amount that exceeds a minimum color temperature discrimination of the human eye over a range of color temperatures from 700 degrees Kelvin to 20,000 degrees Kelvin.  
   
   
       40 . The method of  claim 39 , wherein the first color temperature differs from the second color temperature by up to 2200 degrees Kelvin.