Silica layers and antireflection film using same

Abstract

A silica layer is provided which is usable as a low refractive index undergoing no change in its refractive index. Further, a silica layer is provided which is highly productive and usable as a medium or high refractive index layer undergoing neither reduction in transmittance nor change in spectral colors. Still further, an antireflection film using these silica layers is provided. These silica layers are: a silica layer composed of an organic silicon compound, which has a refractive index of not less than 1.40 and not more than 1.46 (λ=550 nm), and whose composition is represented by SiO x C y :H (x=1.6 to 1.9, y=0.2 to 1.0); a carbon-containing silica layer, which has a refractive index of not less than 1.55 and less than 1.80 (λ=550 nm), and whose composition is represented by Sio a C b (a=0.7 to 1.7, b=0.2 to 1.4); and a silica layer containing carbon, which has a refractive index of not less than 1.80 and not more than 2.50 (λ=550 nm), and whose composition is represented by SiO d C e (d=0.5 to 0.9, e=1.0 to 2.0). These silica layers are used to form the antireflection film.

What is claimed is:  
     
         1 . A silica layer comprising an organic silicon compound, which has a refractive index of not less than 1.40 and not more than 1.46 (λ=550 nm), and whose composition is represented by SiO x C y :H (x=1.6 to 1.9, y=0.2 to 1.0).  
     
     
         2 . A silica layer according to  claim 1 , wherein infrared absorption due to C—H stretching vibrations ranges from 0.1 to 1 cm −1 and infrared absorption due to O—H stretching vibrations ranges from 1 to 30 cm −1 .  
     
     
         3 . A silica layer according to  claim 1 , wherein the refractive index has a change by 0.01 or less after a humidity/heat resistance test.  
     
     
         4 . A silica layer according to  claim 1 , which is formed by a plasma CVD method using an organic silicone as a raw material.  
     
     
         5 . A carbon-containing silica layer, which comprising a refractive index of not less than 1.55 and less than 1.80 (λ=550 nm), and whose composition is represented by SiO a C b  (a=0.7 to 1.7, b=0.2 to 1.4).  
     
     
         6 . A silica layer according to  claim 5 , wherein a ratio of silicon-silicon (Si—Si) bonds to all Si atoms' bonds in the silica layer is 1% or less.  
     
     
         7 . A silica layer according to  claim 5 , which is formed by a plasma CVD method using an organic silicone as a raw material.  
     
     
         8 . A carbon-containing silica layer, which comprising a refractive index of not less than 1.80 and not more than 2.50 (λ=550 nm), and whose composition is represented by SiO d C e  (d=0.5 to 0.9, e=1.0 to 2.0).  
     
     
         9 . A silica layer according to  claim 8 , wherein a ratio of silicon-silicon (Si—Si) bonds to all Si atoms' bonds in the silica layer is 1% or less.  
     
     
         10 . A silica layer according to  claim 8 , which is formed by a plasma CVD method using an organic silicone as a raw material.  
     
     
         11 . An antireflection film comprising at least a substrate film and an antireflection multilayered article provided on the substrate film, wherein the antireflection multilayered article contains any of: 
 (A) a silica layer composed of an organic silicon compound, which has a refractive index of not less than 1.40 and not more than 1.46 (λ=550 nm), and whose composition is represented by SiO x C y :H (x=1.6 to 1.9, y=0.2 to 1.0);    (B) a carbon-containing silica layer, which has a refractive index of not less than 1.55 and less than 1.80 (λ550 nm), and whose composition is represented by SiO a C b  (a=0.7 to 1.7, b=0.2 to 1.4); and    (C) a carbon-containing silica layer, which has a refractive index of not less than 1.80 and not more than 2.50 (λ=550 nm), and whose composition is represented by SiO d C e  (d=0.5 to 0.9, e=1.0 to 2.0).    
     
     
         12 . An antireflection film according to  claim 11 , wherein an outermost layer of the antireflection multilayered article is the silica layer (A), and wherein at least one of the silica layer (B) and the silica layer (C) is formed internally from the outermost layer.  
     
     
         13 . An antireflection film according to  claim 11 , wherein the antireflection multilayered article comprises the silica layer (B), the silica layer (C), and the silica layer (A), in order from a side of the substrate film.  
     
     
         14 . An antireflection film according to  claim 11 , wherein the antireflection multilayered article comprises a silica layer (C), a silica layer (A), another silica layer (C), and another silica layer (A), in order from a side of the substrate film.