Patent ID: 6940479
Filing Date: 2005-09-06
Classification: G09G

Abstract:
1. An erasing device for a liquid crystal display image, provided in a liquid crystal display device having a liquid crystal display panel whose pixels are driven by active elements, for erasing a display image on said liquid crystal display panel when a power source of a main body of said liquid crystal display device is turned OFF, comprising: power source OFF detecting circuit detecting that said power source of the main body of said liquid crystal display device is turned OFF; a power source control circuit maintaining, for a certain period after said power source is turned OFF, power to said liquid crystal display panel; and an erasing circuit applying to all pixels in said liquid crystal display panel an OFF-level voltage during the certain period; said liquid crystal display panel including a pixel electrode in each pixel and an opposing electrode that opposes to said pixel electrode, said erasing circuit comprising: a source driver for outputting a video signal to source lines of said liquid crystal display panel; a source driver control circuit controlling said source driver; and an opposing electrode control circuit outputting an opposing electrode signal to said opposing electrode, wherein said power source control circuit outputs to said source driver control circuit a source enable signal which is at a selecting level solely during the certain period and wherein the source enable signal is inputted into said source driver control circuit which, in response to the source enable signal, causes said source driver to apply an OFF voltage as said video signal to said pixel electrode to turn OFF a liquid crystal during the certain period.