Patent ID: 7760178

Claim:
A display driver for outputting a gray scale voltage corresponding to display data representing a gray scale level to a display panel on which a plurality of pixels are arranged, the display driver comprising: a generating circuit for generating a plurality of gray scale voltages corresponding to a plurality of gray scale levels from a reference voltage; a decoder circuit for selecting a gray scale voltage corresponding to said display data from said plurality of gray scale voltages; a first register for setting a first control value of said generating circuit for generating said plurality of gray scale voltages from said reference voltage in order to adjust an amplitude of a gamma characteristics curve, in a graph having a vertical axis representing a gray scale voltage and a horizontal axis representing a gray scale number, which determines a relation between said gray scale levels and said gray scale voltages or brightness levels on said display panel; a second register for setting a second control value of said generating circuit for generating said plurality of gray scale voltages from said reference voltage in order to adjust a gradient of intermediate portions of said gamma characteristics curve, which intermediate portions are located between end portions of said gamma characteristics curve, a third register for setting a third control value of said generating circuit for generating said plurality of gray scale voltages from said reference voltage in order to finely adjust the intermediate portions of said gamma characteristics curve for each gray scale level; a fourth register, different from said first, second and third registers, for setting a fourth control value of said generating circuit for generating said plurality of gray scale voltages from said reference voltage in order to adjust a gray scale level in a horizontal direction parallel to said horizontal axis, with respect to a gray scale voltage in the intermediate portions close to the end portions of said gamma characteristics curve without changing a voltage amplitude of the gamma characteristics curve, and a fifth register, different from said first, second and third registers for setting a fifth control value of said generating circuit for generating said plurality of gray scale voltages from said reference voltage in order to adjust a gray scale voltage ratio among a plurality of gray scale levels in said intermediate portions close to both end portions of the gamma characteristics curve without changing the gradient of the gamma characteristics curve in said intermediate portions.