Application of multi-layer antistatic/antireflective coating to video display screen by sputtering

Abstract

A multi-layer antistatic/antireflective coating having high electrical conductivity (10 3 ohms) and low reflectivity (0.7%) is applied to the outer surface of a video display screen by sputtering. The multi-layer coating includes an inner antistatic layer deposited directly on the video display screen and comprised of ITO, TiO 2 , etc., having a light refractive index in the range of 1.8-2.2 and a thickness in the range of 18-35 nm. The outer antireflective layer is comprised of SiO 2 , MgO, etc., having a light refractive index in the range of 1.3-1.47 and a thickness in the range of 110-140 nm. The multi-layer coating is applied using a sputtering apparatus having a dual vacuum chamber, a diffusion pump connected to one of the chambers, and plural vacuum pumps connected to the diffusion pump and to the dual vacuum chamber with various gauges and valves for monitoring and controlling the sputtering operation.

I claim:  
     
         1 . A multi-layer coating for a video display panel, said coating comprising: 
 an inner metallic antistatic layer disposed on an outer surface of the video display panel having a precisely controlled thickness within a range of 18-35 nm, wherein a light refractive index of said inner antistatic layer is determined by the thickness of said inner antistatic layer and said light refractive index is also precisely controlled within a range of 1.8-2.2; and    an outer antireflective layer disposed on said inner antistatic layer and having a precisely controlled thickness within a range of 110-140 nm, wherein a light refractive index of said outer antireflective layer is also precisely controlled within a range of 1.3-1.47.    
     
     
         2 . The coating of  claim 1  wherein said inner antistatic layer is comprised of a doped metallic oxide.  
     
     
         3 . The coating of  claim 2  wherein said doped metallic oxide is ITO, SnO 2 :F, ZnO:In, ZnO:F, ZnO:Al, ZnO:Sn, or mixtures thereof.  
     
     
         4 . The coating of  claim 1  wherein said outer antireflective layer is comprised of Al 2 O 3 , TiO 2 , ZnO, ZrO 2 , Cr 2 O 3 , MgO, SiO 2 , or mixtures thereof.  
     
     
         5 . The coating of  claim 2  wherein said multi-layer coating has an electrical conductivity on the order of 10 3  ohms.  
     
     
         6 . The coating of  claim 4  wherein said multi-layer coating has a reflectivity on the order of 0.7%.