Reflector with a resistant surface
View Patent ↗A reflector with high total reflection which is resistant to mechanical stresses. The reflector comprises a reflector body and superimposed thereon (a) a functional coating such as a varnish, (b) a reflecting layer structure composed of a reflecting metallic layer and optionally arranged thereon one or several transparent ceramic layers, for example, layers having an optical depth of λ/2. The reflecting layer structure contains, as its surface layer, a protective layer. The protective layer is a silicon oxide of general formula SiO x , wherein x is a number from 1.1 to 2.0, or it is aluminum oxide of formula Al 2 O 3 , in a thickness of 3 nm or more. The protective layer protects the underlying layers from mechanical damages. In the DIN 58196 abrasion test the protected surface does not show any damages after 50 test cycles with 100 abrasion strokes.
1. A reflector which is resistant to mechanical attack and has high total reflectance, comprising a reflector body and arranged thereon in the following sequence:
(a) a functional coating,
(b) a sequence of layers containing (b)(1) one reflective layer and (b)(2) several transparent layers, and
(c) a protective layer as surface layer, the functional coating (a) is (a)(i), a gel film applied by sol-gel process and the gel film is a coating of at least organofunctional silane of a metal compound, or (a)(ii), in the case of the reflector body being aluminum, the gel film (a)(I) and an aluminum oxide layer formed by anodic oxidation of the aluminum reflector body, the aluminum oxide layer being between the gel film (a)(I) and the aluminum reflector body, and
the protective layer is a silicon oxide having the general formula SiO x , where x is a number from 1.1 to 2.0, or an aluminum oxide having the formula Al 2 O 3 , and has a thickness of 3 nm to 20 nm, the protective layer as the surface layer protects subjacent layers against mechanical damage, and the protective layer shows no surface damage in a wiping test according to DIN 58196 after 50 test cycles of 100 wiping strokes each.
2. The reflector according to claim 1 , wherein the protective layer is the silicon oxide having the general formula SiO x , in which x is a number from 1.1 to 2.0.
3. The reflector according to claim 2 , wherein x is 1.8.
4. A process comprising utilizing as a reflector or a light-guide element for artificial light and daylight the reflector according to claim 1 .
5. A process comprising utilizing, in light and lighting technology, the reflector according to claim 1 in a screen workstation light, a primary light, a secondary light, a grid light or an illuminated ceiling, or as a light defector plate.