Simultaneous color and bleach of ECD

In an electrochromic display device having an indicator with an arrangement of a plurality of electrochromic display segments with common electrode means and a plurality of display segment electrodes respectively, adapted to be selectively driven to bleach and color display states with applied bleach and color drive signals respectively of opposite polarity relative to the common electrode means, and an indicator operating circuit having input means for receiving successive applied display select signals for selecting successive bleach and color display segment arrangements, and segment operating circuit means for selectively applying said bleach and color drive signals to the display segment electrodes in accordance with the selected arrangement of each display select signal applied to the input means, the improvement wherein the segment operating circuit means comprises a color balancing circuit for selectively electrically connecting the segment electrodes driven to the color state to establish a common segment electrode potential relative to the common electrode means for balancing the respective color displays.

In a method of successively operating an electrochromic display device having an arrangement of a plurality of electrochromic display segments with common electrode means and a plurality of display segment electrodes respecitvely, adapted to be selectively driven to bleach and color display states with applied bleach and color drive signals respectively of opposite polarity relative to the common electrode means, with successive display select signals establishing successive bleach and color display segment arrangements, comprising the step, for each successive display select signal, of selectively applying said bleach and color drive signals to the display segment electrodes in accordance with the arrangement established by the respective display select signal, the improvement wherein the step of selectively applying the bleach and color drive signals comprises applying a color drive signal only to the segment electrodes of the bleach segments of the preceding display select signal arrangement.

In a method of successively operating an electrochromic display device having an arrangement of a plurality of electrochromic display segments with common electrode means and a plurality of display segment electrodes respectively, adapted to be selectively driven to bleach and color display states with applied bleach and color drive signals respectively of opposite polarity relative to the common electrode means, with successive display select signals establishing successive bleach and color display segment arrangements, comprising the step, for each successive display select signal, of selectively applying said bleach and color drive signals to the display segment electrodes in accordance with the arrangement established by the respective display select signal, the improvement wherein the method further comprises the step, for each successive display select signal, of interconnecting the segment electrodes of the color segments of the respective display select signal arrangment to provide a common color segment electrode potential relative to the common electrode means for balancing the respective color displays.