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:
Sep. 16, 1997
Filed:
Apr. 08, 1996
Roger A Boggs, Wayland, MA (US);
Jurgen M Grasshoff, Hudson, MA (US);
Mark R Mischke, Arlington, MA (US);
Anthony J Puttick, Arlington, MA (US);
Stephen J Telfer, Arlington, MA (US);
David P Waller, Lexington, MA (US);
Kenneth C Waterman, Arlington, MA (US);
Polaroid Corporation, Cambridge, MA (US);
Abstract
Certain squaric acid derivatives are useful for the thermochemical generation of acid. The squaric acid derivatives may be used in imaging media in conjunction with acid-sensitive materials which undergo a color change when contacted by the acid generated from the squaric acid derivatives. Preferably, the acid-sensitive materials undergo an irreversible color change, so that the image can be fixed by neutralizing all the acid generated with excess base, thereby preventing further color change in the image during long term storage.