Light source device and optical filtering assembly thereof

Abstract

An optical filtering assembly comprises a first interference film and a second interference film. The first interference film comprises multiple first film layers and multiple second film layers. The first film layers and the second film layers are alternately stacked. The second interference film comprises multiple third film layers and multiple fourth film layers. The third film layers and the fourth film layers are alternately stacked. An optical constant of the first film layers is same as an optical constant of the third film layers, and an optical constant of the second film layers is same as an optical constant of the fourth film layers, and an Optical Path Difference (OPD) produced in the first interference film is different from an OPD produced in the second interference film.

What is claimed is: 
     
         1 . An optical filtering assembly, comprising:
 a first interference film comprising a plurality of first film layers and a plurality of second film layers, the plurality of first film layers and the plurality of second film layers being alternately stacked in the first interference film; and   a second interference film comprising a plurality of third film layers and a plurality of fourth film layers, the plurality of third film layers and the plurality of fourth film layers being alternately stacked in the second interference film, wherein an optical constant of the plurality of first film layers is same as an optical constant of the plurality of third film layers, and an optical constant of the plurality of second film layers is same as an optical constant of the plurality of fourth film layers, the first interference film and the second interference film are both disposed in a transmission path of a light beam, and an optical path difference (OPD) of the light beam generated by travelling in the first interference film is different from an OPD of the light beam generated by travelling in the second interference film.   
     
     
         2 . The optical filtering assembly as claimed in  claim 1 , further comprising a first transparent substrate, wherein the first interference film and the second interference film are respectively formed at two opposite sides of the first transparent substrate, and the first interference film, the first transparent substrate and the second interference film are all disposed in the transmission path of the light beam, a thickness of the first interference film is different from a thickness of the second interference film. 
     
     
         3 . The optical filtering assembly as claimed in  claim 1 , further comprising a first transparent substrate, wherein the first interference film and the second interference film are respectively formed at two opposite sides of the first transparent substrate, and the first interference film, the first transparent substrate and the second interference film are all disposed in the transmission path of the light beam, a thickness of the first interference film is different from a thickness of the second interference film. 
     
     
         4 . The optical filtering assembly as claimed in  claim 1 , further comprising a first transparent substrate, wherein the first interference film and the second interference film are respectively formed at two opposite sides of the first transparent substrate, and the first interference film, the first transparent substrate and the second interference film are all disposed in the transmission path of the light beam, a thickness of the first interference film is different from a thickness of the second interference film. 
     
     
         5 . The optical filtering assembly as claimed in  claim 1 , further comprising:
 a first transparent substrate disposed in the transmission path of the light beam, wherein the first interference film is formed on the first transparent substrate in order to form a first interference filter; and   a second transparent substrate disposed in the transmission path of the light beam, wherein the second interference film is formed on the second transparent substrate in order to form a second interference filter.   
     
     
         6 . The optical filtering assembly as claimed in  claim 5 , wherein the first interference filter is parallel to the second interference filter. 
     
     
         7 . The optical filtering assembly as claimed in  claim 5 , wherein the first interference filter is neither parallel to nor perpendicular to the second interference filter. 
     
     
         8 . The optical filtering assembly as claimed in  claim 7 , wherein a thickness of the first interference filter is equal to a thickness of the second interference filter. 
     
     
         9 . The optical filtering assembly as claimed in  claim 5 , further comprising:
 a third interference filter disposed in the transmission path of the light beam, comprising:
 a third transparent substrate; and 
 a third interference film formed on the third transparent substrate, and comprising a plurality of fifth film layers and a plurality of sixth film layers, the plurality of fifth film layers and the plurality of sixth film layers being alternately stacked in the third interference film, wherein an optical constant of the plurality of fifth film layers is same as the optical constant of the plurality of first film layers, and an optical constant of the plurality of sixth film layers is same as an optical constant of the plurality of second film layers, the third interference film is disposed in the transmission path of the light beam, and an optical path difference (OPD) of the light beam generated by travelling in the third interference film is different from the OPD of the light beam generated by travelling in the first interference film or the second interference film. 
   
     
     
         10 . The optical filtering assembly as claimed in  claim 1 , further comprising a first transparent substrate, wherein the first interference film and the second interference film are respectively formed at two opposite sides of the first transparent substrate, and the first interference film, the first transparent substrate and the second interference film are all disposed in the transmission path of the light beam, a thickness of the first interference film is different from a thickness of the second interference film. 
     
     
         11 . The optical filtering assembly as claimed in  claim 1 , further comprising a first transparent substrate, wherein the first interference film and the second interference film are respectively formed at two opposite sides of the first transparent substrate, and the first interference film, the first transparent substrate and the second interference film are all disposed in the transmission path of the light beam, a thickness of the first interference film is different from a thickness of the second interference film. 
     
     
         12 . The optical filtering assembly as claimed in  claim 1 , further comprising a first transparent substrate, wherein the first interference film and the second interference film are respectively formed at two opposite sides of the first transparent substrate, and the first interference film, the first transparent substrate and the second interference film are all disposed in the transmission path of the light beam, a thickness of the first interference film is different from a thickness of the second interference film. 
     
     
         13 . The optical filtering assembly as claimed in  claim 1 , further comprising a first transparent substrate, wherein the first interference film and the second interference film are respectively formed at two opposite sides of the first transparent substrate, and the first interference film, the first transparent substrate and the second interference film are all disposed in the transmission path of the light beam, a thickness of the first interference film is different from a thickness of the second interference film. 
     
     
         14 . The optical filtering assembly as claimed in  claim 1 , further comprising a first transparent substrate, wherein the first interference film and the second interference film are respectively formed at two opposite sides of the first transparent substrate, and the first interference film, the first transparent substrate and the second interference film are all disposed in the transmission path of the light beam, a thickness of the first interference film is different from a thickness of the second interference film. 
     
     
         15 . A light source device, comprising:
 a light source emitting a light beam;   an optical filtering assembly as claimed in  claim 1 , disposed in disposed in   a transmission path of the light beam   
     
     
         16 . The light source device as claimed in  claim 15 , further comprising a first transparent substrate, wherein the first interference film and the second interference film are respectively formed at two opposite sides of the first transparent substrate, and the first interference film, the first transparent substrate and the second interference film are all disposed in the transmission path of the light beam, a thickness of the first interference film is different from a thickness of the second interference film. 
     
     
         17 . The light source device as claimed in  claim 15 , further comprising a first transparent substrate, wherein the first interference film and the second interference film are respectively formed at two opposite sides of the first transparent substrate, and the first interference film, the first transparent substrate and the second interference film are all disposed in the transmission path of the light beam, a thickness of the first interference film is different from a thickness of the second interference film. 
     
     
         18 . The light source device as claimed in  claim 15 , further comprising a first transparent substrate, wherein the first interference film and the second interference film are respectively formed at two opposite sides of the first transparent substrate, and the first interference film, the first transparent substrate and the second interference film are all disposed in the transmission path of the light beam, a thickness of the first interference film is different from a thickness of the second interference film. 
     
     
         19 . The light source device as claimed in  claim 15 , further comprising a first transparent substrate, wherein the first interference film and the second interference film are respectively formed at two opposite sides of the first transparent substrate, and the first interference film, the first transparent substrate and the second interference film are all disposed in the transmission path of the light beam, a thickness of the first interference film is different from a thickness of the second interference film. 
     
     
         20 . An optical filtering assembly, comprising:
 a first interference film comprising a plurality of film layers having a first thickness distribution; and   a second interference film comprising a plurality of film layers each of which has a second thickness, wherein an optical constant of the plurality of first film layers is same as an optical constant of the plurality of third film layers, and an optical constant of the plurality of second film layers is same as an optical constant of the plurality of fourth film layers, the first interference film and the second interference film  120  are both disposed in a transmission path of a light beam, and an optical path difference (OPD) of the light beam generated by travelling in the first interference film is different from an OPD of the light beam generated by travelling in the second interference film.   
     
     
         21 . The optical filtering assembly as claimed in  claim 20 , further comprising a first transparent substrate, wherein the first interference film and the second interference film are respectively formed at two opposite sides of the first transparent substrate, and the first interference film, the first transparent substrate and the second interference film are all disposed in the transmission path of the light beam, a thickness of the first interference film is different from a thickness of the second interference film. 
     
     
         22 . The optical filtering assembly as claimed in  claim 20 , further comprising a first transparent substrate, wherein the first interference film and the second interference film are respectively formed at two opposite sides of the first transparent substrate, and the first interference film, the first transparent substrate and the second interference film are all disposed in the transmission path of the light beam, a thickness of the first interference film is different from a thickness of the second interference film.