Correction of LCD drive voltage in dependence upon LCD switching element turn on time between polarity changes

• Main Authors: KIMURA; YASUHIRO, YOSHIDA; TOSHIHIKO, NISHI; SATORU
• Format: Patent
• Language: English
• Published: 06.04.1999
• Edition: 6
• Subjects: ADVERTISING; ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICESUSING STATIC MEANS TO PRESENT VARIABLE INFORMATION; CRYPTOGRAPHY; DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; DISPLAY; EDUCATION; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; SEALS; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF

In order to display an image on a liquid crystal display at a constant image quality independently of a change of the length of the period for applying voltages with the same polarity to the liquid crystal, the length of one cycle of a horizontal synchronizing signal inputted to an LCD unit from an information processor is counted and the amplitude of data voltage and the center of the amplitude are corrected so that the amplitude of the data voltage to be applied to the liquid crystal increases and a correction value for the center of the amplitude increases as the length of the period for applying data voltages with the same polarity to the liquid crystal decreases in accordance with the length of one cycle of the horizontal synchronizing signal and whether to perform gate overlap scan. Thereby, the absolute values (V) of inter-electrode voltages after the TFT is turned off are equalized independently of the polarity of data voltage to be applied to the liquid crystal both for a relatively long period and for a relatively short period.