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:
Feb. 16, 1993
Filed:
May. 18, 1990
Kark-Heinz Etzbach, Frankenthal, DE;
Gerhard Wagenblast, Frankenthal, DE;
Wolfgang Brox, Heidelberg, DE;
Axel Paul, Mannheim, DE;
Volker Bach, Neustadt, DE;
BASF Aktiengesellschaft, Ludwigshafen, DE;
Abstract
Novel laser-optical recording elements which can be repeatedly erased and recorded on contain recording layers (a) which exhibit enantiotropic, ferroelectric smectic liquid crystalline (S.sub.C*) behavior, so that they can be switched back and forth between two thermodynamically stable, optically distinguishable ferroelectric smectic liquid crystlaline S.sub.C* order states on exposure to a laser beam of sufficient luminous power, by applying an external electric field. The recording layers (a) themselves consist mainly or exclusively of novel polymers P having chiral mesogenic side groups. The novel polymers P are prepared using the novel monomers of the general formula I ##STR1## where R is hydrogen, chlorine or methyl, A is a flexible space-maintaining long-chain molecular moiety, and C is an optically active chiral molecular moiety and B is a mesogenic molecular moiety composed of at least three aromatic nuclei which are bonded linearly or virtually linearly to one another, or they are prepared using the novel monomers I which contain specially selected molecular moieties B in a novel combination with selected molecular moieties C.