First surface mirror with chromium nitride layer

Abstract

A mirror (e.g., first surface mirror) is provided with a layer of or including chromium nitride (CrN x ). In certain example embodiments, the CrN x layer may be the primary reflective layer of the mirror. Surprisingly and unexpectedly, it has been found the addition of nitrogen to the chromium to form CrN x reduces pinhole formations in the resulting layer. In certain example embodiments, the more nitrogen which is introduced into the layer, the smaller the number and/or size of pinholes in the Cr inclusive layer. In certain example embodiments, it has also been found that the addition of nitrogen to Cr may improve durability.

1 . A mirror comprising: 
 a substrate supporting a coating,    wherein the coating includes at least a reflective layer comprising chromium nitride.    
   
   
       2 . The mirror of  claim 1 , wherein the mirror has a visible transmission of no greater than 5%.  
   
   
       3 . The mirror of  claim 1 , wherein the mirror has a visible transmission of no greater than 2.0%.  
   
   
       4 . The mirror of  claim 1 , wherein the substrate is composed of glass, and wherein the layer comprising chromium nitride is located on and in direct contact with the substrate.  
   
   
       5 . The mirror of  claim 1 , wherein a dielectric layer is provided between the substrate and the layer comprising chromium nitride.  
   
   
       6 . The mirror of  claim 1 , wherein the chromium nitride is represented by CrN x , where x is from 0.01 to 0.5.  
   
   
       7 . The mirror of  claim 1 , wherein the chromium nitride is represented by CrN x , where x is from 0.01 to 0.25.  
   
   
       8 . The mirror of  claim 1 , wherein the chromium nitride is represented by CrN x , where x is from 0.01 to 0.15.  
   
   
       9 . The mirror of  claim 1 , wherein the layer comprising chromium nitride is from 200 to 700 Å thick.  
   
   
       10 . The mirror of  claim 1 , wherein the layer comprising chromium nitride is from 250 to 600 Å thick.  
   
   
       11 . The mirror of  claim 1 , wherein the mirror is a first surface mirror.  
   
   
       12 . The mirror of  claim 1 , wherein the mirror has film side reflective a* color of from −2.0 to +2.0, and film side reflective b* color of from −3.0 to +1.5.  
   
   
       13 . The mirror of  claim 1 , wherein the mirror has film side reflective a* color of from −1.0 to +1.0, and film side reflective b* color of from −1.5 to +1.0.  
   
   
       14 . The mirror of  claim 1 , wherein the layer comprising chromium nitride is the only reflective layer of the mirror.  
   
   
       15 . The mirror of  claim 1 , wherein the layer comprising chromium nitride is nitrogen graded so that a first portion thereof contains more nitrogen than a second portion thereof.  
   
   
       16 . The mirror of  claim 1 , wherein a first portion of the layer comprising chromium nitride located closer to the substrate contains more nitrogen than does a second portion of the layer comprising chromium nitride that is located further from the substrate.  
   
   
       17 . The mirror of  claim 1 , further comprising a metallic Cr layer on the substrate, wherein the metallic Cr layer is located over the layer comprising chromium nitride.  
   
   
       18 . A mirror comprising: 
 a glass substrate supporting a layer comprising chromium nitride, and    wherein the mirror has a visible transmission of no greater than 5%.    
   
   
       19 . The mirror of  claim 18 , wherein the mirror has a visible transmission of no greater than 2.5%.  
   
   
       20 . The mirror of  claim 18 , wherein the mirror has a visible transmission of no greater than 2.0%.  
   
   
       21 . The mirror of  claim 18 , wherein the layer comprising chromium nitride is located on and in direct contact with the substrate.  
   
   
       22 . The mirror of  claim 18 , wherein a dielectric layer is provided between the glass substrate and the layer comprising chromium nitride.  
   
   
       23 . The mirror of  claim 18 , wherein the chromium nitride is represented by CrN x , where x is from 0.01 to 0.5.  
   
   
       24 . The mirror of  claim 18 , wherein the chromium nitride is represented by CrN x , where x is from 0.01 to 0.25.  
   
   
       25 . The mirror of  claim 18 , wherein the chromium nitride is represented by CrN x , where x is from 0.01 to 0.15.  
   
   
       26 . The mirror of  claim 18 , wherein the layer comprising chromium nitride is from 200 to 700 Å thick.  
   
   
       27 . The mirror of  claim 18 , wherein the mirror is a first surface mirror.  
   
   
       28 . The mirror of  claim 18 , wherein the mirror has film side reflective a* color of from −2.0 to +2.0, and film side reflective b* color of from −3.0 to +1.5.  
   
   
       29 . The mirror of  claim 18 , wherein the mirror has film side reflective a* color of from −1.0 to +1.0, and film side reflective b* color of from −1.5 to +1.0.  
   
   
       30 . The mirror of  claim 18 , wherein the layer comprising chromium nitride is the only reflective layer of the mirror.  
   
   
       31 . The mirror of  claim 18 , wherein a first portion of the layer comprising chromium nitride located closer to the substrate contains more nitrogen than does a second portion of the layer comprising chromium nitride located further from the substrate.  
   
   
       32 . The mirror of  claim 18 , further comprising a metallic Cr layer on the substrate, wherein the metallic Cr layer is located over the layer comprising chromium nitride.  
   
   
       33 . A method of making a mirror, the method comprising: 
 providing a glass substrate;    sputtering a target comprising Cr in an atmosphere comprising nitrogen gas in order to form a layer comprising chromium nitride on the glass substrate; and    wherein said sputtering comprises using a nitrogen gas flow in the atmosphere which represents from about 1-21% of total gas flow in the atmosphere.    
   
   
       34 . The method of  claim 33 , wherein said sputtering comprises using a nitrogen gas flow in the atmosphere which represents from about 3-19% of total gas flow in the atmosphere.  
   
   
       35 . The method of  claim 33 , wherein said sputtering comprises using a nitrogen gas flow in the atmosphere which represents from about 5-18% of total gas flow in the atmosphere.  
   
   
       36 . The method of  claim 33 , further comprising forming another layer on the substrate, so that said another layer is located between the substrate and the layer comprising chromium nitride.  
   
   
       37 . The method of  claim 33 , wherein the mirror has a visible transmission of no greater than 5%.  
   
   
       38 . The method of  claim 33 , wherein the mirror is a first surface mirror.  
   
   
       39 . The method of  claim 33 , wherein the sputtering is performed so as to cause the mirror to have a film side reflective a* color of from −2.0 to +2.0, and a film side reflective b* color of from −3.0 to +1.5.  
   
   
       40 . A mirror comprising: 
 a substrate supporting a coating,    wherein the coating includes at least a reflective layer comprising a metal nitride, wherein the metal is nitrided sufficiently so as to reduce pinholes and so that the mirror has a film side reflective a* color of from −2.0 to +2.0, and a film side reflective b* color of from −3.0 to +1.5.    
   
   
       41 . The mirror of  claim 40 , wherein the metal is one of chromium and aluminum.