| 摘要 |
PROBLEM TO BE SOLVED: To prevent the fluctuation in contrast at the time of subordinately changing the contrast of a display device, such as an LCD, between independent units. SOLUTION: The analog contrast control signal from a first unit 2 is subjected to A/D conversion at the start-up of a second unit 1 and the height of the contrast is judged by using a plurality of thresholds of a predetermined threshold table based on the level of the signal converted to a digital signal in order to control the contrast of the display device 1a of the second unit 1 to a plurality of stages based on the analog contrast signal from the first unit 2 between the first and second units 1 and 2 which are independent from each other. The contrast of the display device 1a is then controlled based on the height of the contrast. At this time, the two thresholds are slid in such a manner that the level of the digital signal exists in the middle of the two adjacent thresholds of the threshold table and the other thresholds are slid at the same width to provide the fresh threshold table. COPYRIGHT: (C)2005,JPO&NCIPI
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