Light source assemblies

Abstract

A light source assembly comprises: a light pipe and one or more tapered light collectors operative to reduce the angular distribution of light entering the light pipe from light sources at one or more ports. Dichroic filters and angle-dependent, wavelength selective pass filters control light flow into and through the light pipe. The tapered light collector is operative to reduce the angular distribution of light entering the light pipe. At least a first dichroic filter positioned in the light pipe optically between first and second light entrances is operative to pass first color light from the first light source toward the light port, and to reflect second color light from the second light source toward the light port.

1 . A light source assembly comprising, in combination: 
 a light pipe forming at least a light port and an elongate axial optical pathway from first and second light entrances to the light port, the second light entrance being axially spaced along the light pipe from the first light entrance; 
 a first tapered light collector at the first light entrance, operative to reduce the angular distribution of a first color light to be fed into the light pipe via the first tapered light collector;  
 a second tapered light collector at the second light entrance, operative to reduce the angular distribution of a second color light, different from the first color light, to be fed into the light pipe via the second tapered light collector; and  
 at least a first dichroic filter positioned in the light pipe optically between the first and second light entrances and operative as oriented in the light pipe to pass first color light from the first light source toward the light port, and to reflect second color light from the second light source toward the light port.  
   
   
   
       2 . The light source assembly of  claim 1  further comprising: 
 a first light source operative to generate first color light into the light pipe at the first light entrance via the first tapered light collector; and    a second light source operative to generate second color light, different from the first color light, into the light pipe via the second tapered light collector.    
   
   
       3 . The light source assembly of  claim 2  wherein at least one of the first and second tapered light collectors comprises a tapered hollow light pipe fixedly integrated with the light pipe.  
   
   
       4 . The light source assembly of  claim 2  further comprising a short wave pass filter positioned at the first or second light entrance.  
   
   
       5 . The light source assembly of  claim 2  wherein the first dichroic filter is positioned in the light pipe at a 30° to 60° angle to the axial optical pathway.  
   
   
       6 . The light source assembly of  claim 2  wherein the second light entrance is located axially along the light pipe between the first light entrance and the light port, and wherein the light source assembly further comprises a primary second light entrance filter positioned at the second light entrance in a plane generally parallel to the elongate axial optical pathway, the second light entrance filter being operative: 
 c. to pass at least second color light having an angle of incidence of from 0° to 30° upon the primary second light entrance filter, and    d. to reflect at least 
 i. second color light having an angle of incidence of from 60° to 90° upon the primary second light entrance filter, and  
 ii. first color light having an angle of incidence of from 0° to 30° upon the primary second light entrance filter.  
   
   
   
       7 . The light source assembly of  claim 6  wherein the primary second light entrance filter is a short wave pass filter.  
   
   
       8 . The light source assembly of  claim 6  further comprising reflective surface at the perimeter of at least one of the light entrances operative to provide recirculation of at least a portion of the light from the associated light source.  
   
   
       9 . The light source assembly of  claim 6  further comprising reflective surface at the perimeter of the second light entrance, and wherein 
 a. the second light collector increases in size toward an opening at the second light entrance into the light pipe,    b. the opening of the light collector is larger than the second light entrance, and    c. the reflective surface at the perimeter of the second light entrance is operative to reflect back at least a portion of the light from the second light source which does not pass through the primary second light entrance filter.    
   
   
       10 . The light source assembly of  claim 6  further comprising a secondary second light entrance filter positioned in the axial optical pathway optically between the second light entrance and the light port, the secondary second light entrance filter being operative: 
 a. to pass at least 
 i. first color light having an angle of 0° to 30° to the axial optical pathway to the light port, and  
 ii. second color light having an angle of 0° to 30° to the axial optical pathway to the light port; and  
   b. to reflect at least second color light having an angle of 60° to 90° to the axial optical pathway to the light port.    
   
   
       11 . The light source assembly of  claim 10  wherein the secondary second light entrance filter is oriented normal to the axial optical pathway.  
   
   
       12 . The light source assembly of  claim 10  wherein the secondary second light entrance filter is a short wave pass filter.  
   
   
       13 . The light source assembly of  claim 2  further comprising: 
 a. at least one light valve positioned to receive light passed from the light pipe via the light port, and    b. at least one focusing relay lens positioned between the light port and the light valve and operative to focus light passed from the light pipe via the light port to the light valve.    
   
   
       14 . The light source assembly of  claim 2  wherein the dichroic filter has an index of refraction n greater than 1.9.  
   
   
       15 . The light source assembly of  claim 2  further comprising: 
 a third tapered light collector at a third light entrance to the light pipe, the third light entrance being axially spaced from the first and second light entrances and located between the second light entrance and the optical port;    a third light source operative to generate a third color light, different from the first and second color lights, into the light pipe via the third tapered light collector, the third tapered light collector being operative to reduce the angular distribution of the third color light entering the light pipe from the third light source; and    at least a second dichroic filter positioned in the axial optical pathway optically between the second light entrance and the third light entrance, 30° to 60° angle to the axial optical pathway, the second dichroic filter being operative to pass first and second color light from the first and second light sources, respectively, toward the light port and to reflect third color light from the third light source toward the light port;    wherein the light pipe is operative to homogenize the first, second and third color lights passed simultaneously to the light port from the first, second and third light sources, respectively.    
   
   
       16 . The light source assembly of  claim 15  further comprising: 
 a. a primary second light entrance filter positioned at the second light entrance in a plane generally parallel to the axial optical pathway, the second light entrance filter being operative: 
 i. to pass at least second color light having an angle of incidence of from 0° to 30° upon the primary second light entrance filter, and  
 ii. to reflect at least 
 second color light having an angle of incidence of from 60° to 90° upon the primary second light entrance filter, and  
 first color light having an angle of incidence of from 0° to 30° upon the primary second light entrance filter; and  
 
   b. a primary third light entrance filter positioned at the third light entrance in a plane generally parallel to the axial optical pathway, the second light entrance filter being operative: 
 iii. to pass at least second color light having an angle of incidence of from 0° to 30° upon the primary second light entrance filter, and  
 iv. to reflect at least 
 second color light having an angle of incidence of from 60° to 90° upon the primary second light entrance filter, and  
 first color light having an angle of incidence of from 0° to 30° upon the primary second light entrance filter.  
 
   
   
   
       17 . The light source assembly of  claim 15  further comprising: 
 a. a secondary second light entrance filter positioned in the axial optical pathway optically between the second light entrance and the light port, the secondary second light entrance filter being operative: 
 i. to pass at least 
 first color light having an angle of 0° to 30° to the axial optical pathway to the light port, and  
 second color light having an angle of 0° to 30° to the axial optical pathway to the light port; and  
 
 ii. to reflect at least second color light having an angle of 60° to 90° to the axial optical pathway to the light port; and  
   b. a secondary third light entrance filter positioned in the axial optical pathway optically between the third light entrance and the light port, the secondary third light entrance filter being operative: 
 i. to pass at least first, second and third color light having an angle of 0° to 30° to the axial optical pathway, and  
 ii. to reflect at least third color light having an angle of 60° to 90° to the axial optical pathway.  
   
   
   
       18 . The light source assembly of  claim 15  wherein: 
 a. the light pipe comprises a hollow elongate rectangular pipe segment extending from a first axial end of the rectangular pipe segment to the light port at a second axial end of the rectangular pipe segment;    b. the first light entrance is an axial entrance at the first axial end of the rectangular pipe segment;    c. the second light entrance is a lateral entrance through a side wall of the rectangular pipe segment; and    d. the third light entrance is a lateral entrance through a side wall of the rectangular pipe segment.    
   
   
       19 . The light source assembly of  claim 15  wherein the first light source comprises a green LED, the second light source comprises a blue LED and the third light source comprises a red LED.  
   
   
       20 . The light source assembly of  claim 15  wherein the third light source comprises a green LED.  
   
   
       21 . The light source assembly of  claim 15  wherein the first light source is a red LED, the second light source is a green LED, and the third light source is a blue LED.  
   
   
       22 . The light source assembly of  claim 1  wherein at least one of the first and second tapered light collectors is an anamorphic collector.  
   
   
       23 . The light source assembly of  claim 2  wherein at least one of the first and second tapered light collectors is a focusing light collector operative to focus light from the associated light source into the light pipe.  
   
   
       24 . The light source assembly of  claim 2  wherein at least one of the first and second tapered light collectors is a non-focusing light collector.  
   
   
       25 . A light source assembly comprising, in combination: 
 an light pipe forming at least a light port and an elongate axial optical pathway to the light port;    a first tapered light collector;    a first light source operative to generate a first color light into the light pipe at a first light entrance via the first tapered light collector, the first tapered light collector being operative to reduce the angular distribution of the first color light entering the light pipe from the first light source;    a second tapered light collector;    a second light source operative to generate a second color light, different from the first color light, into the light pipe via the second tapered light collector at a second light entrance axially spaced from the first light entrance, the second tapered light collector being operative to reduce the angular distribution of the second color light entering the light pipe from the second light source; and    at least a first dichroic filter comprising a thin film filter and positioned in the light pipe optically between the first and second light entrances and operative as oriented in the light pipe—   to pass first color light from the first light source toward the light port, and    to reflect second color light from the second light source toward the light port.