Optical device and adhesive composition used therefor

Abstract

An optical device having at least two optically transparent optical parts which are bonded together with an optically transparent adhesive layer. The adhesive layer is formed from a matrix containing silicon, titanium, zirconium, aluminum or germanium, and oxygen atoms. At least part of the atoms is bonded to other atom(s) through a polyvalent hydrocarbon group and directly bonded a monovalent hydrocarbon group. The refractive index value of the adhesive layer approximates to the refractive index values of the at least two optically transparent optical parts. An adhesive composition for bonding optical parts and a method of bonding optical parts are also proposed.

What is claimed is:  
     
         1 . An optical device comprising at least two optically transparent optical parts which are bonded together with an optically transparent adhesive layer, wherein the adhesive layer is formed from a matrix containing at least one type of specific atoms selected from the group consisting of silicon, titanium, zirconium, aluminum and germanium, and oxygen atoms, at least part of the specific atoms is bonded to other specific atom(s) through a polyvalent hydrocarbon group having 2 to 8 carbon atoms and directly bonded to at least one monovalent hydrocarbon group selected from the group consisting of an alkyl group, phenyl group, monovalent fluorine-containing hydrocarbon group and monovalent sulfur-containing hydrocarbon group, and the contents of the above specific atom, the polyvalent hydrocarbon group and the monovalent hydrocarbon group are adjusted such that the refractive index value of the adhesive layer approximates to the refractive index values of the at least two optically transparent optical parts.  
     
     
         2 . The optical device of  claim 1 , wherein when the refractive index values of the two adjacent optical parts are represented by n 1  and n 2  (n 1 ≧n 2 ), the adhesive layer between the adjacent optical parts has a refractive index n 3  represented by the following expression (1):  
       {square root}{square root over (( n   1   ·n   2 ))}−(({square root}{square root over (( n   1   ·n   2 ))}− n   2 )/3)−0.05 ≦n   3 ≦{square root}{square root over (( n   1   ·n   2 ))}+(( n   1 −{square root}{square root over (( n   1   n   2 ))})/3)+0.05  (1)  
     
     
         3 . The optical device of  claim 1 , wherein when the refractive index values of the two adjacent optical parts are represented by n 1  and n 2  (n 1 ≧n 2 ), the adhesive layer between the adjacent optical parts has a refractive index n 3  represented by the following expression (2):  
       {square root}{square root over (( n   1   ·n   2 ))}−(({square root}{square root over (( n   1   ·n   2 ))}− n   2 )/4)−0.03 ≦n   3 ≦{square root}{square root over (( n   1   ·n   2 ))}+(( n   1 −{square root}{square root over (( n   1   n   2 ))})/4)+0.03  (2)  
     
     
         4 . The optical device of any one of  claims 1  to  3 , wherein the adhesive layer contains the polyvalent hydrocarbon group and the monovalent hydrocarbon group in amounts of 0.01 to 30 wt % and 30 to 80 wt %, respectively.  
     
     
         5 . The optical device of any one of  claims 1  to  4 , wherein the optical parts are optical fibers, lenses, filters, optical waveguides, diffraction gratings or optical active elements.  
     
     
         6 . The optical device of any one of  claims 1  to  5 , wherein one of the at least two optical parts is an optical fiber and the other optical part is a lens, filter or optical waveguide.  
     
     
         7 . The optical device of any one of  claims 1  to  5 , wherein the at least two optical parts are both optical fibers.  
     
     
         8 . The optical device of any one of  claims 1  to  7 , wherein the at least two optical parts are made from glass, plastic or organic-inorganic composite material.  
     
     
         9 . The optical device of any one of  claims 1  to  7 , wherein the at least two optical parts are made from glass.  
     
     
         10 . An adhesive composition for bonding optical parts comprising the following components (A), (B) and (C): 
 (A) organopolysiloxane having at least two alkenyl groups having 4 or less carbon atoms bonded to silicon atoms in the molecule;    (B) organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in the molecule; and    (C) a platinum-based catalyst.    
     
     
         11 . The adhesive composition of  claim 10 , wherein the component (A) has a viscosity of 100 to 250,000 cS at 25° C.  
     
     
         12 . The adhesive composition of  claim 10  or  11 , wherein the number of hydrogen atoms contained in the component (B) is 0.4 to 6.0 times the total number of alkenyl groups contained in the component (A), and the component (C) is contained in an amount of 10 to 1,000 ppm based on the total weight of the component (A) and the component (B).  
     
     
         13 . A method of bonding optical parts comprising the steps of placing an adhesive composition comprising the following components (A), (B) and (C) between at least two optical parts to be bonded together and curing the adhesive composition: 
 (A) organopolysiloxane having at least two alkenyl groups having 4 or less carbon atoms bonded to silicon atoms in the molecule;    (B) organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in the molecule; and    (C) a platinum-based catalyst.    
     
     
         14 . The method of bonding optical parts of  claim 13 , wherein the component (A) has a viscosity of 100 to 250,000 cS at 25° C.  
     
     
         15 . The method of bonding optical parts of  claim 13  or  14 , wherein the number of hydrogen atoms contained in the component (B) is 0.4 to 6.0 times the total number of alkenyl groups contained in the component (A), and the component (C) is contained in an amount of 10 to 1,000 ppm based on the total weight of the component (A) and the component (B).