US 11,967,295 B2
Display driver and display device using independent test polarity inversion signal
Hiroaki Ishii, Yokohama (JP)
Assigned to LAPIS Technology Co., Ltd., Yokohama (JP)
Filed by LAPIS Technology Co., Ltd., Yokohama (JP)
Filed on Sep. 5, 2022, as Appl. No. 17/902,914.
Claims priority of application No. 2021-148391 (JP), filed on Sep. 13, 2021.
Prior Publication US 2023/0077595 A1, Mar. 16, 2023
Int. Cl. G09G 3/36 (2006.01)
CPC G09G 3/3614 (2013.01) [G09G 2300/0823 (2013.01); G09G 2310/0291 (2013.01); G09G 2320/046 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A display driver comprising:
a conversion part which converts first to n-th display data pieces representing a brightness level of each pixel based on an image signal into first to n-th gradation voltages each having a voltage value corresponding to the brightness level, and outputs the first to n-th gradation voltages, where n is an integer of 2 or more;
a polarity inversion signal generation circuit which generates a polarity inversion signal for prompting polarity inversion for a frame display period according to the image signal;
a first external terminal which receives an operation mode signal representing a test mode or a normal mode; and
a first selector which receives the operation mode signal from the first external terminal, a test polarity inversion signal for prompting polarity inversion and the polarity inversion signal, wherein the first selector selects and outputs the polarity inversion signal when the operation mode signal represents the normal mode, and the first selector selects and outputs the test polarity inversion signal when the operation mode signal represents the test mode,
wherein the test polarity inversion signal is independent from the polarity inversion signal,
wherein the conversion part inverts a polarity of the voltage value of each of the output first to n-th gradation voltages according to a signal output by the first selector from among the test polarity inversion signal and the polarity inversion signal.