DIGITAL GAMMA CORRECTING METHOD AND LIQUID CRYSTAL DEVICE USING THE SAME

• Main Author: KABURAGI CHIHARU
• Format: Patent
• Language: English
• Published: 29.10.1999
• 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; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; PICTORIAL COMMUNICATION, e.g. TELEVISION; SEALS; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF

PROBLEM TO BE SOLVED: To provide a high-accuracy, high-speed and low-cost digital gamma correcting method by providing simplified and detailed modes for converting the gradation of a digital video signal according to gamma correction data generated while using simplified and detailed characteristics approximate to the driving voltage/transmission factor characteristics of a liquid crystal panel. SOLUTION: In the simplified mode, first of all, the parameter of simplified V-T characteristics is read from a ROM 6, the simplified V-T characteristics are reproduced in a RAM for work inside a CPU 5, and the gamma correction data are calculated and stored in an LUT 1 corresponding to a driving voltage range. In the detailed mode, on the other hand, the parameter of detailed V-T characteristics is read from the ROM 6, the detailed V-T characteristics are reproduced in the RAM for work inside the CPU 5, and the gamma correction data are calculated and stored in the LUT 1 corresponding to the driving voltage range. Then, prescribed gamma correction is performed for digital video data 100 by the LUT 1, digital/analog conversion is performed for corrected digital video data 101 by a DAC 2 and an analog video signal 102 is outputted.