Driver circuit for electrochromic display device

Claim 1

In an electronic device having an electrochromic display device having a common electrode connected to a power supply and a plurality of segment electrodes associated therewith to provide a display of information, the combination comprising: a logic circuit including means for generating display information signals in a parallel form, a timing pulse generator for generating clock pulses, and a parallel/serial converter connected to said display information signal generating means for generating serial output data in response to said display information signals and said clock pulses; and a driver circuit including a serial/parallel converter having its input connected to an output of said parallel/serial converter and producing parallel output data in response to said serial output data and said clock pulses, said serial/parallel converter also producing a serial data as a previous display data in response to said serial output data and said clock pulses, a detection circuit receiving said serial output data as a new display data and said serial data as a previous display data and comparing these data for producing a non-coincidence signal when said new display data and said previous display data are out of coincidence, a segment selection circuit responsive to said non-coincidence signal for generating a segment selection signal to select only a segment whose display state is to be changed, and a plurality of driver means one of which is selected in response to said selection signal to produce bleaching and coloring signals in response to said parallel output data for thereby driving only said segment whose display state is to be changed.