Antireflection coating for ultraviolet light at large angles of incidence

US6697194B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Ralf Kuschnereit · Oberkochen, DE
• Hans-Jochen Paul · Aalen, DE

Key dates

• Filing date: Dec 12, 2001
• Grant date: Feb 24, 2004
• Expiry date: Mar 13, 2022

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B1/11
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

Antireflection multilayer coatings with only three or four layers are proposed for the production of laser resistant optical components with minimal residual reflection and high transparency for UV light in a wavelength range approx. 150 nm to approx. 250 nm at large angles of incidence in the range of approx. 70° to approx. 80°, particularly in the range between approx. 72° and approx. 76°. For incident p-polarized UV light three-layer systems can be used, in which a layer of low refractive material, in particular magnesium fluoride is arranged between two layers of high refractive material and, in the case of the specified wavelength, of minimally absorbent material, in particular of hafnium oxide or aluminum oxide. For example, this allows a residual reflection of perceptibly less than 1% to be achieved in the case of a wavelength of 248 nm at angles of incidence in the range between approx. 72° and approx. 76°.