Apparatus for washing glass substrates and process for producing a liquid crystal device

Abstract

Dirt, particularly of inorganic matter, attached to a substrate, such as a glass substrate for liquid crystal devices, is effectively removed by irradiating the substrate with ultraviolet rays including 184.9 nm and 253.7 nm in an oxygen-containing atmosphere in advance of wet cleaning with pure water. As a result, the wet cleaning time and the amount of pure water can be reduced.

What is claimed is:  
     
         1 . A method of cleaning a substrate for removing dirt on the substrate, comprising: irradiating a substrate surface with ultraviolet rays including wavelengths of 184.9 nm and 253.7 nm in an oxygen-containing atmosphere, and then subjecting the substrate to wet cleaning with pure water.  
     
     
         2 . A method according to  claim 1 , wherein said oxygen-containing atmosphere comprises atmospheric air.  
     
     
         3 . A method according to  claim 1 , wherein said ultraviolet rays are generated from a discharge lamp.  
     
     
         4 . A method according to  claim 1 , wherein said ultraviolet rays are generated from an excimer laser.  
     
     
         5 . A method according to  claim 1 , wherein said ultraviolet rays are generated from a plurality of sources.  
     
     
         6 . A method according to  claim 5 , wherein at least one of the sources issues a wavelength selected from 184.9 nm and 253.7 nm.  
     
     
         7 . A method according to  claim 1 , wherein at least one of the wavelengths of 184.9 nm and 253.7 nm is a peak wavelength.  
     
     
         8 . A method according to  claim 1 , wherein the substrate is irradiated with ultraviolet rays at an intensity of at least 0.2 J/cm 2 .  
     
     
         9 . A method according to  claim 1 , wherein the substrate is subjected to the wet cleaning with pure water within 30 min. after the irradiation with ultraviolet rays.  
     
     
         10 . A method according to  claim 1 , wherein said substrate comprises a glass substrate.  
     
     
         11 . A method according to  claim 1 , wherein the substrate is subjected to the wet cleaning when the substrate surface shows a contact angle with water of at most 10 degrees after the irradiation with ultraviolet rays.  
     
     
         12 . A method according to  claim 1 , wherein the substrate comprises a substrate for a liquid crystal device.  
     
     
         13 . A method according to  claim 1 , wherein the substrate comprises a glass substrate provided with a transparent electrode.  
     
     
         14 . A method according to  claim 13 , wherein said transparent electrode comprises indium tin oxide.  
     
     
         15 . A method according to  claim 1 , wherein the substrate after the wet cleaning is further irradiated with ultraviolet rays.  
     
     
         16 . A method according to  claim 15 , wherein the ultraviolet rays include wavelengths at 184.9 nm and 253.7 nm.