MULTIPLEX DRIVING CIRCUIT

• US 3,786,486 A
• Filed: 08/11/1971
• Issued: 01/15/1974
• Est. Priority Date: 08/11/1971
• Status: Expired due to Term

• Current Assignee: Vincenzo N. Torresi
• Original Assignee: Vincenzo N. Torresi
• Inventors: Torresi, Vincenzo N.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Curtis, Marshall M.
• Application Number:
  US05/170,803
• Time in Patent Office: 888 Days
• Field of Search: 340/324R,336,324M 350/16R,16LC 315/169TV
• US Class Current: 345/52
• CPC Class Codes: G02F 1/13392 spacers dispersed on the cell substrate, e.g. spherical particles, microfibres
• CPC Class Codes: G09G 3/18 using liquid crystals

Abstract

A multiplex circuit for driving a multicharacter liquid crystal display, each character having a segmented and a common electrode, which selectively applies an actuating voltage to selected segmented electrodes of all the characters in parallel while applying an AC erasing voltage to the common electrodes of all the nonselected characters. The common electrode of the selected character is set to a reference potential.

Claims

1. A multiplex driving circuit for a multicharacter liquid crystal display, each of said characters including a plurality of individually actuable electrodes and a common electrode comprising:

sequential means for sequentially connecting a reference potential to the common electrode of successive ones of said characters and means blockable by said connecting means for applying an AC erasing signal to the common electrodes of said characters, and means synchronized with said sequential means for selectively applying an actuating potential to corresponding ones of said individually energizable electrodes of said characters in parallel.

2. The multiplex circuit of claim 1 wherein said means synchronized with said sequential means further includes means for biasing said individually actuable electrodes of said characters to a potential below the threshold actuation potential of the liquid crystal material.

3. The multiplex circuit of claim 1 wherein said means for selectively applying an actuation potential includes means for storing an encoded indication of a character to be displayed and means for decoding said indication for applying an actuation potential to selected ones of said individually actuable electrodes for displaying the character corresponding to said encoded indication.

4. The multiplex circuit of claim 3 further including means for synchronizing the reading by said storage means of the next character to be displayed and the connection by said sequential means of said reference potential to the common electroDe of the next character to be actuated.

5. A multiplex driving circuit for a multicharacter liquid crystal display, each of said characters including a plurality of individually energizable electrodes and a common electrode, comprising:

sequential means connected to the common electrodes of all of said characters including means for connecting a reference potential to the common electrode of successive ones of said characters and means blockable by said connecting means for continuously applying an AC erasing signal to the common electrodes of said characters, and means connected in parallel to the corresponding ones of said plurality of individually energizable electrodes and synchronized with said sequential means for selectively applying an actuating potential to said corresponding ones of said individually energizable electrodes of said characters in parallel for impressing an actuating potential difference between the selected individually energizable electrodes of the character whose common electrode is held at said reference potential by said sequential means and the common electrode thereof.