Electrochromic display apparatus

In a method of operating an electrochemical electrochromic display apparatus comprising a display cell having an indication electrode, a counter-electrode and an electrochemical electrochromic substance filled between said counter-electrode and said indication electrode,

• the improvement comprising the steps of:
• (a) impressing a predetermined voltage across said indication electrode and a polarizable counter-electrode for a predetermined time period to allow a current to flow across the electrodes to form at least an electrochemical reaction product for electrochromic indication on the surface of said indication electrode, and
• (b) each time before applying said predetermined voltage shortcircuiting said indication electrode and said counter-electrode to each other for a predetermined time period making an inverse current to said current across the electrodes, dissolving said reaction product and thereby erasing said electrochromic indication.

An electrochromic display apparatus comprising:

• (a) a display cell having an indication electrode, a Pt or Au counter-electrode and an electrochemical electrochromic substance filled between said indication electrode and said counter-electrode,
• (b) a voltage-impressing means for impressing a predetermined voltage across said indication electrode and said counter-electrode for a predetermined time period to allow a current to flow across the electrodes to form an electrochromic reaction product for electrochromic indication on the surface of said indication electrode, and
• (c) a shortcircuiting means which, each time before applying said predetermined voltage, shortcircuits said indication electrode and said counter-electrode to each other for another predetermined time period to provide an inverse current to said current across the electrodes to dissolve said electrochemical reaction product and thereby erase said electrochromic indication.

A method of operating an electrochemical electrochromic display apparatus including a display cell having an indication electrode, a counter-electrode and an electrochemical electrochromic substance filled between said counter-electrode and said indication electrode, said method comprising the steps of:

• (a) impressing a predetermined voltage across said indication electrode and a Pt or Au counter-electrode for a predetermined time period to allow a current to flow across the electrodes to form at least an electrochemical reaction product for electrochromic indication on the surface of said indication electrode, and
• (b) each time before applying said predetermined voltage short-circuiting said indication electrode and said counter-electrode to each other for another predetermined time period making an inverse current to said current across the electrodes, dissolving said reaction product and thereby erasing said electrochromic indication.