US 12,242,057 B2
Optical layered composite having two groupings of coating layers and its application in augmented reality
Thorsten Damm, Eltville am Rhein (DE)
Assigned to Schott AG, (DE)
Filed by Schott AG, Mainz (DE)
Filed on Aug. 1, 2019, as Appl. No. 16/529,192.
Claims priority of application No. 18186914 (EP), filed on Aug. 1, 2018.
Prior Publication US 2020/0041794 A1, Feb. 6, 2020
Int. Cl. G02B 27/01 (2006.01); G02B 1/11 (2015.01)
CPC G02B 27/0172 (2013.01) [G02B 1/11 (2013.01); G02B 2027/0112 (2013.01)] 14 Claims
OG exemplary drawing
 
1. An optical layered composite, comprising:
a substrate having a front face, a back face, a thickness ds between the front face and the back face, and a refractive index ns; and
a coating applied to the front face, the coating having two regions, the two regions being a region A and a region B, the region A consisting of one or more coating layers made of a material selected from the group consisting of: Si3N4, ZrO2, Ta2O5, HfO2, TiO2, SnO2, indium tin oxide, ZnO2, AlN, a mixed nitride comprising at least one thereof, and a mixed oxynitride comprising at least one thereof, each of which satisfies at least one of the following criteria:
a thickness below 5 nm; or
a refractive index of 1.6 or more; and
the region B comprises one or more coating layers, each of which satisfies at least one of the following criteria:
a thickness below 5 nm; or
a refractive index below 1.6;
wherein the region A has a greater thickness than the region B, wherein a mean reflectance of the optical layered composite is no greater than 1.0% across a wavelength range of 450 nm to 650 nm and at least one of the following is satisfied:
the thickness ds is in the range from 10 to 1500 μm;
a radius of curvature is greater than 600 mm;
an in-plane optical loss measured perpendicular to the front face is at most 20%;
a surface roughness of the substrate is less than 5 nm;
a surface roughness of the coating is less than 5 nm;
a total thickness variation is less than 5 μm;
a maximum local thickness variation over 75% of the front face is less than 5 μm;
a warp is less than 350 μm; or
a bow is less than 300 μm.