Patent number: 6245403
Abstract: The invention relates to an optical storage medium comprising a substrate and a storage layer, wherein the storage layer comprises a compound of the formula (I) or (II)
in which A and A′, independently of one another, are unsubstituted or mono- or di-halo-, -hydroxy-, —C1-C6alkyl-, —C1-C6alkoxy-, -cyano- or -nitro-substituted phenyl, pyridyl, pyrrolyl, imidazolyl, furyl or thienyl, which can, if desired, be fused to a benzene ring, are halide, tetrafluoroborate or unsubstituted or with one or more halogen substituted C1-C6alkane-sulfonate, benzenesulfonate, C1-C6alkylbenzenesulfonate, C1-C6alkylsulfate or di-C1-C6alkyl-phosphonate of N—C1-C6alkyl-pyridiniumyl, or are unsubstituted or mono- or di-hydroxy-substituted C2-C6alkyl or C2-C6alkenyl, whose chain may be uninterrupted or interrupted by one or two oxygen atoms, B and B′, independently of one another, are 2 H, S, S2 or SO2, and n and n′, independently of one another, are each a number from 1 to 4.
Type:
Grant
Filed:
April 29, 1998
Date of Patent:
June 12, 2001
Assignee:
Ciba Specialty Chemicals Corporation
Inventors:
Heinz Spahni, Jin Mizuguchi, Beat Schmidhalter, Annemarie Wolleb, Jean-Luc Budry, GĂ©rald Giller