The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 22, 1994
Filed:
Apr. 23, 1991
David Trost, San Francisco, CA (US);
Philip Baumeister, Newcastle, CA (US);
Dennis Fischer, Auburn, CA (US);
Coherent, Inc., Santa Clara, CA (US);
Abstract
A dichroic optical filter including a substrate that is substantially transparent to visible radiation, and an oxide semiconductor layer on the substrate for reflecting an infrared wavelength (such as an infrared treatment beam wavelength). An example of a suitable oxide semiconductor for reflecting a treatment beam from a CO.sub.2 layer is indium tin oxide. Preferably, the filter includes a specially designed multilayer coating on the oxide semiconductor layer to enhance the reflection of infrared and longer wavelength radiation. This multilayer coating includes alternating quarter-wave layers of high and low refractive index materials, each having an optical thickness substantially equal to a quarter-wavelength of infrared radiation to be reflected. Preferably also, the multilayer coating includes a thin multilayer coating between each pair of adjacent quarter-wave layers, with these thin multilayer coatings being designed to enhance the filter's transmission of visible radiation, while not significantly affecting the filter's reflection of infrared wavelengths. Also preferably, the multilayer coating includes a second multilayer coating which reflects a narrow band of visible radiation (such as visible radiation from a HeNe laser aiming beam), while transmitting most visible wavelengths.