First surface mirror with chromium nitride layer
View Patent ↗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,
wherein the chromium nitride is represented by CrN x , where x is from 0.01 to 0.25;
wherein the mirror has a visible transmission of no greater than 5%, and wherein the mirror has a film side reflectance of at least 60%;
a metallic Cr layer located over the layer comprising chromium nitride; and
wherein the layer comprising chromium nitride is nitrogen graded so that a first portion thereof contains more nitrogen than a second portion thereof.
2. The mirror of claim 1 , wherein the mirror has a visible transmission of no greater than 2.0%.
3. 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.
4. The mirror of claim 1 , wherein a dielectric layer is provided between the substrate and the layer comprising chromium nitride.
5. The mirror of claim 1 , wherein the chromium nitride is represented by CrN x , where x is from 0.01 to 0.15.
6. The mirror of claim 1 , wherein the layer comprising chromium nitride is from 200 to 700 Å thick.
7. The mirror of claim 1 , wherein the layer comprising chromium nitride is from 250 to 600 Å thick.
8. The mirror of claim 1 , wherein the mirror is a first surface mirror.
9. 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.
10. 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.
11. The mirror of claim 1 , wherein the metallic Cr layer located over the layer comprising chromium nitride is the uppermost layer of the coating and exposed to atmosphere in the final mirror product.
12. A mirror comprising:
a substrate supporting a coating,
wherein the coating includes at least a reflective layer comprising chromium nitride, wherein the chromium nitride is represented by CrN x , where x is from 0.01 to 0.25;
wherein the mirror has a visible transmission of no greater than 5%, and wherein the mirror has a film side reflectance of at least 60%;
a metallic Cr layer located over the layer comprising chromium nitride; and
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.