Electrically conductive polymers and their use as orienting layer in liquid-crystal switching and display elements

US5118538A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Claus Escher · Mühltal, DE
• Hans-Rolf Dubal · Königstein, DE
• Michael Feldhues · Bad Soden am Taunus, DE
• Takamasa Harada · Oberursel, DE
• Gerhard Illian · Frankfurt am Main, DE
• Thomas Mecklenburg · Rockenberg, DE
• Mikio Murakami · Kakegawa, JP
• Dieter Ohlendorf · Liederbach, DE
• Karl Pampus · Kelkheim, DE

Key dates

• Filing date: Aug 3, 1990
• Grant date: Jun 2, 1992
• Expiry date: Aug 3, 2010

Classification

• Technology area (CPC G): Physics
• CPC primary: G02F1/141
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

Switching and display elements based on ferroelectric liquid-crystals often exhibit a pronounced optical hysteresis which results in the appearance of so-called ghost images. This phenomenon can be markedly reduced or even suppressed if at least one of the two orienting layers are in direct contact with the electrodes and is composed of an electrically conductive polymer of the formula (I): ##STR1## in which R.sup.1, R.sup.2 =independently of each other, H, or straight-chain or branched alkyl or alkoxy containing 1-16 carbon atoms, or halogen, PA1 X=S, NH, PA1 Y.sup.- =BF.sub.4.sup.-, PF.sub.6.sup.-, PO.sub.4.sup.3-, AsF.sub.6.sup.-, SbCl.sub.6.sup.-, SO.sub.4.sup.2-, HSO.sub.4.sup.-, alkyl--SO.sub.3.sup.-, perfluoroalkyl--SO.sub.3.sup.-, aryl--SO.sub.3, F.sup.- or Cl.sup.-, and PA1 n is an integer from 4 to 100 and PA1 m is an integer from 1 to 30.