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:
May. 06, 1980
Filed:
Apr. 03, 1978
Giorgio B Trapani, Cambridge, MA (US);
Polaroid Corporation, Cambridge, MA (US);
Abstract
A rigidly bonded electro-optic phase retardation device comprising a transparent, electrically induced ferroelectric ceramic element bonded with a rigid adhesive in sandwich-like configuration between transparent sheet elements, such as glass, or polarizer elements is described. The electro-optic phase retardation device, provided with means for applying an electric field across at least a portion of the induced ferroelectric ceramic element, can be utilized as a birefringent optical device for controllable modulation of polarized light passing through the device. The device is bonded with an adhesive material, such as a cross-linked unsaturated polyester, effective to provide a rigid boundary between the ceramic material and the sheet elements thereof and exhibits rapid optical response speed in the switching from a field-induced birefringent mode to an isotropic zero-field condition. The device is thus suited to application in welding plates, glasses, goggles, helmets and similar devices for controlling the transmission of light radiations to the wearer's eyes, particularly in the prevention of flashblindness.