Optical filter and optical device utilizing same

Abstract

Provided is an optical filter including first and second reflection layers separated from each other, a dielectric region interposed between the first and second reflection layers and in which two materials of which refractive indexes are different are alternately disposed, and a buffer layer disposed between the dielectric region and at least one of the first and second reflection layers, wherein there are at least two filter regions in which relative volume ratios of the two materials alternately disposed are different.

1 . An optical filter comprising:
 first and second reflection layers separated from each other;   a dielectric region interposed between the first and second reflection layers and in which two materials of which refractive indexes are different are alternately disposed; and   a buffer layer disposed between the dielectric region and at least one of the first and second reflection layers, wherein there are at least two filter regions in which relative volume ratios of the two materials alternately disposed are different.   
     
     
         2 . The optical filter of  claim 1 , wherein the two materials are alternately disposed, and there are at least two filter regions in which relative width ratios of the two materials are different. 
     
     
         3 . The optical filter of  claim 2 , wherein a pair of the two adjacent materials are allowed to respectively have same widths as a pair of two adjacent other materials in one direction. 
     
     
         4 . The optical filter of  claim 1 , wherein the two materials are composed of a first material comprising in plurality and disposed at a pre-determined interval, and a second material surrounding the first material. 
     
     
         5 . The optical filter of  claim 2 , wherein a width of a pair of the two materials is smaller than a wavelength of a light passing through the filter. 
     
     
         6 . The optical filter of  claim 1 , wherein the filter regions, in which relative volume ratios of the two materials are different from each other, are in two or more directions in a plane. 
     
     
         7 . The optical filter of  claim 1 , wherein the first and second reflection layers are a metal layer or a dispersion Bragg reflector (DBR). 
     
     
         8 . The optical filter of  claim 1 , wherein the dielectric region comprises three or more materials. 
     
     
         9 . The optical filter of  claim 1 , wherein the buffer layer is formed of the first or second material. 
     
     
         10 . The optical filter of  claim 1 , wherein an upper part of the second reflection layer comprises a wideband transmission filter and/or anti-reflection coating. 
     
     
         11 . The optical filter of  claim 1 , wherein the filter regions respectively comprise different buffer layers. 
     
     
         12 . An optical filter comprising:
 first and second reflection layers separated from each other;   a dielectric region interposed between the first and second reflection layers and at least two materials, of which refractive indexes are different from each other, are alternately disposed; and   at least two filter regions in which relative volume ratios of the two materials alternately disposed are different from each other,   wherein an intermediate reflection layer parallel to the reflection layers is added to a central region of the dielectric region.   
     
     
         13 . The optical filter of  claim 12 , further comprising:
 buffer layers of which optical thicknesses are identical between the intermediate reflection layer and the first and second reflection layers.   
     
     
         14 . An optical device comprising:
 filter regions in which relative volume ratios of the two materials of  claim 1  are different from each other and through which different wavelengths are passed; and   photodetectors respectively corresponding to the filter regions.   
     
     
         15 . The optical device of  claim 14 , wherein the optical device is a spectroscope, a CMOS image sensor, or a hyper-spectra imaging device. 
     
     
         16 . An optical device comprising:
 a transmissive substrate; and   the optical filter of  claim 1  provided on an upper part of the transmission substrate and integrated in a separate module type.