Light source device

Abstract

A light source device comprising at least a primary light source ( 1 ), a light guide ( 3 ) guiding light beamed from the primary light source and having a light incident surface ( 31 ) and a light outgoing surface ( 33 ), an optical deflector ( 4 ) disposed adjacent to the light guide's light outgoing surface and having a light incident surface ( 41 ) and a light outgoing surface ( 42 ), and a light diffuser ( 6 ) disposed adjacent to the optical deflector's light outgoing surface and having a light incident surface ( 61 ) and a light out going surface ( 62 ), wherein the optical deflector's light incident surface is formed with a plurality of rows of prisms arranged in parallel to each other, and the light diffuser has the full width half maximum of an outgoing light intensity of 1-13 degrees when parallel rays of light are incident, whereby providing a light source device excellent in light utilization efficiency of a primary light source, and also excellent in viewing angle characteristics and quality as an image forming illumination without sacrificing high brightness characteristics.

1 . A light source device comprising, at least, a primary light source, a light guide that guides light emitted from said primary light source and has a light incident surface on which the light emitted from said primary light source is incident, and a light outgoing surface from which the guided light exits, a light deflector having a light entrance surface disposed adjacent to the light outgoing surface of said light guide and located so as to face said light outgoing surface, and a light exit surface on an opposite side relative to said light entrance surface, and a light diffuser having an incident surface disposed adjacent to the light exit surface of said light deflector and located so as to face the light exit surface of said light deflector, and an outgoing surface on an opposite side relative to said incident surface, 
 wherein a plurality of elongated prisms arrayed side by side are formed at the light entrance surface of said light deflector, each of said elongated prisms has two prism surfaces and, at least one of said prism surfaces is formed into a convex curved surface shape, and the two prism surfaces intersect at a point facing the light guide, and said light diffuser is configured in such a manner that a full width half maximum of an outgoing light luminous intensity distribution is 1 to 13 degrees when parallel light is incident thereon.    
     
     
         2 . A light source device according to  claim 1 , wherein a haze value of said light diffuser is 8 to 82%.  
     
     
         3 . A light source device according to  claim 1  or  2 , wherein an average inclination angle of at least one of the incident surface and the outgoing surface of said light diffuser is 0.8 to 12 degrees.  
     
     
         4 - 6 . (canceled)  
     
     
         7 . A light source device comprising, at least, a primary light source, a light guide that guides light emitted from said primary light source and has a light incident surface on which the light emitted from said primary light source is incident, and a light outgoing surface from which the guided light exits, a light deflector having a light entrance surface disposed adjacent to the light outgoing surface of said light guide and located so as to face said light outgoing surface, and a light exit surface on an opposite side relative to said light entrance surface, and a light diffuser having an incident surface disposed adjacent to the light exit surface of said light deflector and located so as to face the light exit surface of said light deflector, and an outgoing surface on an opposite side relative to said incident surface, 
 wherein a plurality of elongated prisms arrayed side by side are formed at the light entrance surface of said light deflector, each of said elongated prisms has two prism surfaces and, at least one of said prism surfaces is formed into a convex curved surface shape, and the two prism surfaces intersect at a point facing the light guide, and an average inclination angle of at least one of the incident surface and the outgoing surface of said light diffuser is 0.8 to 12 degrees.    
     
     
         8 . A light source device according to  claim 7 , wherein said light diffuser is configured in such a manner that a full width half maximum of an outgoing light luminous intensity distribution is 1 to 13 degrees when parallel light is incident thereon.  
     
     
         9 . A light source device according to  claim 7  or  8 , wherein a haze value of said light diffuser is 8 to 82%.  
     
     
         10 . A light source device according to any one of claims  1  and  8 , wherein a developed length of said light guide is 8 cm or less, and said light diffuser is configured in such a manner that the full width half maximum of the outgoing light luminous intensity distribution is 1 to 6 degrees when the parallel light is incident thereon.  
     
     
         11 . A light source device according to  claim 2 , wherein a developed length of said light guide is 8 cm or less, and the haze value of said light diffuser is 8 to 60%.  
     
     
         12 . A light source device according to  claim 3 , wherein a developed length of said light guide is 8 cm or less, and the average inclination angle of at least one of the incident surface and the outgoing surface of said light diffuser is 0.8 to 5 degrees.  
     
     
         13 . A light source device according to any one of claims  1  and  8 , wherein a developed length of said light guide is greater than 8 cm and equal to or less than 23 cm, and said light diffuser is configured in such a manner that the full width half maximum of the outgoing light luminous intensity distribution is 3 to 11 degrees when the parallel light is incident thereon.  
     
     
         14 . A light source device according to  claim 2 , wherein a developed length of said light guide is greater than 8 cm and equal to or less than 23 cm, and the haze value of said light diffuser is 30 to 80%.  
     
     
         15 . A light source device according to  claim 3 , wherein a developed length of said light guide is greater than 8 cm and equal to or less than 23 cm, and the average inclination angle of at least one of the incident surface and the outgoing surface of said light diffuser is 3 to 9.5 degrees.  
     
     
         16 . A light source device comprising, at least, a primary light source, a light guide that guides light emitted from said primary light source and has a light incident surface on which the light emitted from said primary light source is incident, and a light outgoing surface from which the guided light exits, a light deflector having a light entrance surface disposed adjacent to the light outgoing surface of said light guide and located so as to face said light outgoing surface, and a light exit surface on an opposite side relative to said light entrance surface, and a light diffuser having an incident surface disposed adjacent to the light exit surface of said light deflector and located so as to face the light exit surface of said light deflector, and an outgoing surface on an opposite side relative to said incident surface, 
 wherein a plurality of elongated prisms arrayed side by side are formed at the light entrance surface of said light deflector, each of said elongated prisms has two prism surfaces and, at least one of said prism surfaces is formed into a convex curved surface shape, and the two prism surfaces intersect at a point facing the light guide, and a full width half maximum of a luminance distribution of outgoing light from the light exit surface of said light deflector is 19 to 26 degrees, and said light diffuser is configured in such a manner that a full width half maximum of an outgoing light luminous intensity distribution is 1 to 8 degrees when parallel light is incident thereon.    
     
     
         17 . A light source device according to  claim 16 , wherein a haze value of said light diffuser is 8 to 70%.  
     
     
         18 . A light source device according to  claim 16  or  17 , wherein an average inclination angle of at least one of the incident surface and the outgoing surface of said light diffuser is 0.8 to 7 degrees.  
     
     
         19 . A light source device comprising, at least, two primary light sources, a light guide that guides lights emitted from said primary light sources and has two light incident surfaces on which the lights emitted from said two primary light sources are respectively incident and which are disposed on opposite sides to each other, and a light outgoing surface from which the guided lights exit, said light guide having a developed length greater than 8 cm and equal to or less than 28 cm, a light deflector having a light entrance surface disposed adjacent to the light outgoing surface of said light guide and located so as to face said light outgoing surface, and a light exit surface on an opposite side relative to said light entrance surface, and a light diffuser having an incident surface disposed adjacent to the light exit surface of said light deflector and located so as to face the light exit surface of said light deflector, and an outgoing surface on an opposite side relative to said incident surface, 
 wherein a plurality of elongated prisms arrayed side by side are formed at the light entrance surface of said light deflector, each of said elongated prisms has two prism surfaces and, at least one of said prism surfaces is formed into a convex curved surface shape, and the two prism surfaces intersect at a point facing the light guide, and said light diffuser is configured in such a manner that a full width half maximum of an outgoing light luminous intensity distribution is 0.7 to 13 degrees when parallel light is incident thereon.    
     
     
         20 . A light source device according to any one of claims  1 ,  2 ,  7 ,  8 ,  16 ,  17 , and  19 , wherein an average inclination angle of the incident surface of said light diffuser is greater than an average inclination angle of the outgoing surface thereof.  
     
     
         21 . A light source device according to any one of claims  1 ,  2 ,  7 ,  8 ,  16 ,  17 , and  19 , wherein the incident surface and the outgoing surface of said light diffuser have a convex-concave structure.  
     
     
         22 . A light source device comprising, at least, a primary light source, a light guide that guides light emitted from said primary light source and has a light incident surface on which the light emitted from said primary light source is incident, and a light outgoing surface from which the guided light exits, a light deflector having a light entrance surface disposed adjacent to the light outgoing surface of said light guide and located so as to face said light outgoing surface, and a light exit surface on an opposite side relative to said light entrance surface, and a light diffuser having an incident surface disposed adjacent to the light exit surface of said light deflector and located so as to face the light exit surface of said light deflector, and an outgoing surface on an opposite side relative to said incident surface, 
 wherein said light diffuser is configured in such a manner that a full width half maximum of an outgoing light luminous intensity distribution has an anisotropy when parallel light is incident thereon, and includes a plurality of elongated prisms arrayed side by side are formed at the light entrance surface of said light deflector, at least one of said elongated prisms includes a convex curved shape, and each of said elongated prisms has two curved prism surfaces that intersect at a point facing the light guide.    
     
     
         23 . A light source device according to  claim 22 , wherein said light diffuser is configured in such a manner that a maximum full width half maximum of the outgoing light luminous intensity distribution is 1 to 13 degrees when the parallel light is incident thereon.  
     
     
         24 . A light source device according to  claim 22  or  23 , wherein said light diffuser is configured in such a manner that a maximum full width half maximum of the outgoing light luminous intensity distribution is 1.1 times a minimum full width half maximum thereof or greater when the parallel light is incident thereon.  
     
     
         25 . A light source device according to any one of claims  22  or  23 , wherein a haze value of said light diffuser is 8 to 82%.  
     
     
         26 . A light source device according to any one of claims  22  or  23 , wherein an average inclination angle of at least one of the incident surface and the outgoing surface of said light diffuser has an anisotropy.  
     
     
         27 . A light source device according to  claim 25 , wherein a maximum average inclination angle of at least one of the incident surface and the outgoing surface of said light diffuser is 0.8 to 15 degrees.  
     
     
         28 . A light source device according to  claim 23 , wherein a developed length of said light guide is 8 cm or less, and said light diffuser is configured in such a manner that the maximum full width half maximum of the outgoing light luminous intensity distribution is 1 to 6 degrees when the parallel light is incident thereon.  
     
     
         29 . A light source device according to any one of claims  22 ,  23 , and  28 , wherein a developed length of said light guide is 8 cm or less, and a haze value of said light diffuser is 8 to 60%.  
     
     
         30 . A light source device according to any one of claims  22 ,  23 , and  28 , wherein a developed length of said light guide is 8 cm or less, and a maximum average inclination angle of at least one of the incident surface and the outgoing surface of said light diffuser is 0.8 to 5 degrees.  
     
     
         31 . A light source device according to  claim 23 , wherein a developed length of said light guide is greater than 8 cm and equal to or less than 23 cm, and said light diffuser is configured in such a manner that the maximum full width half maximum of the outgoing light luminous intensity distribution is 3 to 13 degrees when the parallel light is incident thereon.  
     
     
         32 . A light source device according to any one of claims  22 ,  23 , and  31 , wherein a developed length of said light guide is greater than 8 cm and equal to or less than 23 cm, and a haze value of said light diffuser is 30 to 80%.  
     
     
         33 . A light source device according to any one of claims  22 ,  23 , and  31 , wherein a developed length of said light guide is greater than 8 cm and equal to or less than 23 cm, and a maximum average inclination angle of at least one of the incident surface and the outgoing surface of said light diffuser is 3 to 15 degrees.  
     
     
         34 . A light source device according to any one of claims  22 ,  23 ,  28 , and  31 , wherein a maximum average inclination angle of the incident surface of said light diffuser is greater than a maximum average inclination angle of the outgoing surface thereof.  
     
     
         35 . A light source device according to  claim 34 , wherein the maximum average inclination angle of the incident surface of said light diffuser is 1.1 times a minimum average inclination angle thereof or greater.  
     
     
         36 . (canceled)