Article including a non-light-emitting variable transmission device and a coating
An article can include a non-light-emitting, variable transmission device and a coating disposed between the non-light-emitting, variable transmission device and an ambient outside the article. In an embodiment, the article has a ΔE of at most 6.5. In another embodiment, the coating includes a plurality of layers including a first layer having a refractive index of at least 2.2 and a thickness of at least 10 nm. The coating can be used to help reduce color differences seen when the non-light-transmitting, variable transmission device is taken to different transmission states. In a particular embodiment, the coating can provide a good balance between color difference and luminous transmission.
1 . An article comprising:
a non-light-emitting, variable transmission device on a substrate;
a coating disposed between the non-light-emitting, variable transmission device and an ambient outside the article, wherein the coating comprises a plurality of layers including a first layer having a refractive index of at least 2.2 and a thickness of between 17 nm and 40 nm wherein the coating comprises silicon-zirconium oxynitride; and
wherein the article has a color difference delta E(ΔE) in the range of 1.0 to 6.5, wherein:
Δ E =( L* 21 2 +a* 21 2 +b* 21 2 ) 0.5 ,
L* 21 is the difference in L* when the article is in its lowest transmission state minus L* when the article is in its highest transmission state,
a* 21 is the difference in a* when the article is in its lowest transmission state minus a* when the article is in its highest transmission state,
b* 21 is the difference in b* when the article is in its lowest transmission state minus b* when the article is in its highest transmission state,
measurements for L*, a*, and b* are taken along the same side of the article as the outer surface, wherein L* represents the lightness of color, a* represents a position between red/magenta and green, and b* represents a position between yellow and blue according to CIELab color space, wherein when the article is in its highest transmission state, the article comprises a luminous transmission in a range of 40% to 60%.
2 . The article of claim 1 , wherein the coating includes a second layer having a refractive index less than the first layer.
3 . The article of claim 2 , wherein the second layer is a barrier layer with respect to an alkali metal.
4 . The article of claim 2 , wherein the second layer comprises a nitride material.
5 . The article of claim 2 , wherein the second layer has a thickness of at least 11 nm and the second layer has a thickness of at most 50 nm.
6 . The article of claim 5 , wherein the substrate is composed of glass and is disposed between the coating and the non-light-transmission, variable transmission device, wherein the glass substrate has a refractive index in a range of 1.4 to 1.7.
7 . The article of claim 2 , wherein the second layer has a refractive index of at most 1.7.
8 . The article of claim 1 , further comprising a second layer is disposed between the first layer and the non-light-emitting variable transmission device.
9 . The article of claim 8 , further comprising a third layer, wherein the second layer is disposed between the first and third layer.
10 . The article of claim 9 , wherein the second layer has a refractive index less than the first and third layer.
11 . The article of claim 1 , wherein the coating is on the substrate.
12 . The article of claim 1 , wherein the ΔE is in the range of 1.0 to 5.0.
13 . The article of claim 1 , wherein the ΔE is in the range of 2.0 to 6.5.
14 . The article of claim 1 , wherein the ΔE is in the range of 1.0 to 6.0.