Optical element having a water repellant coating constructed from a composite material of CaF2 and TiO2
US6383629B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 5, 2001 |
| Grant date | May 7, 2002 |
| Priority date | — |
| Expiry date | Feb 5, 2021 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/265
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An optical element having a water repellant composite layer composed of CaF2 and TiO2. The optical element includes a substrate and a composite layer having a chemical formula (100-X)CaF2—(X)TiO2 formed over the substrate. The X in the chemical formula represents the molar percentage of TiO2 in the composite layer. Through the addition of TiO2 into a CaF2 layer to form the composite layer, surface roughness, adhesion strength and hardness of the layer in the optical element is improved without compromising water resistant capacity. For a composite layer having a percentage composition of TiO2 between 2% to 100%, contact angle of water droplets is always greater than 100° comparable with Teflon. The refractive index varies according to the composition, but in general, the refractive index falls between 1.23 (2%TiO2) to 2.3 (pure TiO2) for incoming light with a wavelength of 600 nm. Aside from having a good water repellant capacity, the composite layer can also be used as an anti-reflection layer or a layer with special optical properties in an optoelectronic/optical element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.