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:
Jun. 05, 1990
Filed:
Jun. 02, 1989
Donald W Roy, Golden, CO (US);
James L Hastert, Lakewood, CO (US);
Coors Porcelain Company, Golden, CO (US);
Abstract
A dome and window for missiles and launch tubes is provided having high ultraviolet transmittance and high strength properties. The domes and windows have, in their uncoated state, and with a thickness of about 1.88 mm, a transmittance greater than about 80%, preferably greater than about 82%, and more preferably greater than about 85%, at a wavelength of 0.4 microns to 0.5 microns. The domes and windows preferably have a transmittance per 1.88 mm thickness at all wavelengths in the wavelength range between 3.0 microns and 4.0 microns of at least about 81%. The domes and windows have a flexural strength of at least about 20,000 psi and a knoop hardness of at least about 1350 kg mm.sup.-2. The domes and windows are formed of a transparent, sintered polycrystalline magnesia-alumina spinel. The polycrystalline sintered spinel is formed in a two-step process comprising forming a closed porosity body such as by hot-pressing or pressureless sintering followed by a hot isostatic pressure treatment step to reduce residual porosity to less than about 0.001 percent.