Patent ID: 7724269

Claim:
A display driver for use with a first screen and a second screen, the display driver comprising: a data line drive circuit which supplies gray scale voltages to the first and second screens in accordance with display data, via data lines used in common by the first and second screens; and a scan line drive circuit which supplies scan signals to the first and second screens via respective first and second scan lines; wherein the first scan lines are disposed from the scan line drive circuit to the first screen, and are different from the second scan lines disposed from the scan line drive circuit to the second screen; wherein in a case where the first screen is in a display mode and the second screen is in a non-display mode, the scan line drive circuit supplies scan signals to at least one of the second scan lines but less than all the second scan lines, in one of a one-line-at-a-time operation and a plural-line-at-a-time operation, by supplying scan signals to the second screen every time the scan line drive circuit supplies scan signals to at least one frame of the first screen in a one-line-at-a-time operation; and wherein in a case where the first screen is in a non-display mode and the second screen is in a display mode, the scan line drive circuit supplies scan signals to at least one of the first scan lines but less than all the first scan lines, in one of a one-line-at-a-time operation and a plural-line-at-a-time operation, by supplying scan signals to the first screen every time the scan line drive circuit supplies scan signals to at least one frame of the second screen in a one-line-at-a-time operation.