Dielectric mirror
View Patent ↗A dielectric mirror includes a coating having alternating high and low index layers. The mirror coating has no metallic reflective layer of Al or Ag in certain example embodiments, and may have film side and/or glass side visible reflection of from about 50-90% (more preferably from about 60-80% and most preferably from about 65-75%) and visible transmission of from about 10-50% (more preferably from about 10-40% or 20-40%) in certain example embodiments.
1. A dielectric mirror including a substrate supporting a coating, the coating comprising moving away from the substrate:
a first dielectric layer having a thickness of from about 70-140 nm and a refractive index (n) of from about 2.15 to 2.5;
a second dielectric layer comprising silicon oxide;
a third dielectric layer having a refractive index of from about 2.15 to 2.5;
a fourth dielectric layer comprising silicon oxide;
a fifth dielectric layer having a refractive index of from about 2.15 to 2.5;
wherein the first dielectric layer is at least 10 nm thicker than one or both of the third dielectric layer and/or the fifth dielectric layer;
wherein the coating does not contain any metallic reflective layer;
wherein the mirror has a visible film side reflectance and/or a visible glass side reflectance of from about 50-90%, and visible transmission of from about 10-50%; and
wherein the glass side visible reflectance of the mirror is at least about 30% higher or at least about 30% lower than is the film side visible reflectance of the mirror.
2. The mirror of claim 1 , wherein at least one of the first, third and fifth dielectric layers comprises niobium oxide.
3. The mirror of claim 1 , wherein at least one of the first, third and fifth dielectric layers comprises titanium oxide.
4. The mirror of claim 1 , wherein the first dielectric layer is at least 10 nm thicker than both of the third and fifth dielectric layers.
5. The mirror of claim 1 , wherein the second and fourth dielectric layers comprising silicon oxide are each: (i) thinner than the first dielectric layer, and (ii) thicker than both the third and fifth dielectric layers.
6. The mirror of claim 1 , wherein the mirror has neutral glass side reflective and film side reflective color values a* and b*, each of the glass side and film side reflective a* and b* values being from about −2 to +2.
7. The mirror of claim 1 , wherein the mirror further comprises a layer comprising silicon nitride located between the substrate and the first dielectric layer.
8. A dielectric mirror including a substrate supporting a coating, the coating comprising moving away from the substrate:
a first dielectric layer having a refractive index (n) of from about 2.15 to 2.5;
a second dielectric layer comprising silicon oxide;
a third dielectric layer having a refractive index of from about 2.15 to 2.5;
a fourth dielectric layer comprising silicon oxide;
a fifth dielectric layer having a refractive index of from about 2.15 to 2.5;
wherein the first dielectric layer is at least 20 nm thinner than one or both of the third dielectric layer and/or the fifth dielectric layer;
wherein the coating does not contain any metallic reflective layer %; and
wherein the glass side visible reflectance of the mirror is at least about 30% higher or at least about 30% lower than is the film side visible reflectance of the mirror.
9. The mirror of claim 8 , wherein the mirror has a visible film side reflectance and/or a visible glass side reflectance of from about 40-90%, and visible transmission of from about 20-60%.
10. The mirror of claim 8 , wherein at least one of the first, third and fifth dielectric layers comprises niobium oxide.
11. The mirror of claim 8 , wherein at least one of the first, third and fifth dielectric layers comprises titanium oxide.
12. The mirror of claim 8 , wherein the first dielectric layer is at least 20 nm thinner than both of the third and fifth dielectric layers.
13. The mirror of claim 8 , wherein the second dielectric layer comprising silicon oxide is: (i) thicker than the first dielectric layer, and (ii) thinner than each of the third and fifth dielectric layers.
14. The mirror of claim 8 , wherein the glass side and film side visible reflectance of the mirror are substantially the same.
15. The mirror of claim 8 , wherein the mirror has neutral glass side and/or film side reflective color values a* and b*, each of the glass side and/or film side reflective a* and b* values being from about −2 to +2.
16. The mirror of claim 8 , wherein the mirror further comprises a layer comprising silicon nitride located between the substrate and the first dielectric layer.
17. The mirror of claim 8 , wherein the first dielectric layer is at least 40 nm thinner than both of the third dielectric layer and the fifth dielectric layer.
18. A dielectric mirror including a substrate supporting a coating, the coating comprising moving away from the substrate:
a first dielectric layer having a thickness of from about 70-140 nm and a refractive index (n) of from about 2.15 to 2.5;
a second dielectric layer comprising silicon oxide;
a third dielectric layer having a refractive index of from about 2.15 to 2.5;
a fourth dielectric layer comprising silicon oxide;
a fifth dielectric layer having a refractive index of from about 2.15 to 2.5;
wherein the first dielectric layer is at least 10 nm thicker than one or both of the third dielectric layer and/or the fifth dielectric layer;
wherein the coating does not contain any metallic reflective layer;
wherein the mirror has a visible film side reflectance and/or a visible glass side reflectance of from about 50-90%, and visible transmission of from about 10-50%; and
wherein the coating consists essentially of the first, second, third, fourth and fifth layers.