Wavlength specific coating for mirrored optics and method for reducing reflection of white light

Abstract

An amorphous diamond coating applied onto mirrored optics in an infrared motion sensor to block specific wavelengths of energy from a “white light” source like a halogen lamp, without reducing the reflectivity of the mirror surface in the Mid-Infrared wavelengths. A specific thickness of diamond-like-coating is applied on top of the reflective metal surface of a mirrored part, thereby reducing the mirror's reflectivity at visible and near-Infrared wavelengths known to be problematic for IR motion sensors, such as those emitted from halogen lamps. The coating has no significant detrimental effect on mid-infrared reflectivity, so the IR motion sensor's performance is otherwise unaffected.

What is claimed is:  
     
         1 . A method of reducing the incidence of visible and near-infrared light impinging on a reflective surface of an optical reflector, comprising overlaying said reflective surface with a layer of non-crystalline carbon material.  
     
     
         2 . A method as recited in  claim 1 , wherein said non-crystalline carbon material comprises amorphous diamond.  
     
     
         3 . A method as recited in  claim 1 , wherein said non-crystalline carbon material comprises a diamond-like coating.  
     
     
         4 . A method of reducing the incidence of visible and near-infrared light impinging on a reflective surface of an optical reflector, comprising coating said reflective surface with a diamond-like coating.  
     
     
         5 . A method as recited in  claim 4 , wherein said diamond-like coating comprises a non-crystalline carbon material.  
     
     
         6 . A method as recited in  claim 4 , wherein said diamond-like coating comprises an amorphous diamond material.  
     
     
         7 . A mirror, comprising: 
 (a) a substrate base;    (b) a layer of reflective material adjacent to said substrate base; and    (c) a light absorbing layer adjacent to said layer of reflective material.    
     
     
         8 . A mirror as recited in  claim 7 , wherein said light absorbing layer comprises a non-crystalline carbon material.  
     
     
         9 . A mirror as recited in  claim 7 , wherein said light absorbing layer comprises an amorphous diamond material.  
     
     
         10 . A mirror as recited in  claim 7 , wherein said light absorbing layer comprises a diamond like coating.  
     
     
         11 . A mirror as recited in  claim 7 , wherein said light absorbing layer absorbs light in the visible and near-infrared regions.  
     
     
         12 . A mirror, comprising: 
 (a) a substrate base;    (b) a layer of reflective material adjacent to said substrate base; and    (c) a diamond-like coating over said layer of reflective material.    
     
     
         13 . A mirror as recited in  claim 12 , wherein said diamond-like coating absorbs light.  
     
     
         14 . A mirror as recited in  claim 12 , wherein said diamond-like coating absorbs light in the visible and near-infrared regions.  
     
     
         15 . A mirror as recited in  claim 12 , wherein said diamond-like coating comprises a non-crystalline carbon material.  
     
     
         16 . A mirror as recited in  claim 12 , wherein said diamond-like coating comprises an amorphous diamond material.  
     
     
         17 . A mirror, comprising: 
 (a) a substrate base;    (b) a layer of reflective material adjacent to said substrate base; and    (c) a layer of non-crystalline carbon material adjacent to said layer of reflective material, wherein said layer of reflective material is between said substrate base and said layer of non-crystalline carbon material.    
     
     
         18 . A mirror as recited in  claim 17 , wherein said non-crystalline carbon material absorbs light.  
     
     
         19 . A mirror as recited in  claim 17 , wherein said non-crystalline carbon material absorbs light in the visible and near-infrared regions.  
     
     
         20 . A mirror as recited in  claim 17 , wherein said non-crystalline carbon material comprises a diamond-like coating.  
     
     
         21 . A mirror as recited in claim  20 , wherein said non-crystalline carbon material comprises an amorphous diamond material.