| 摘要 |
PROBLEM TO BE SOLVED: To achieve a properly bright display at any time on map screens for both day- and nighttime uses, and to suppress producing a reversal phenomenon of a display especially on a map display used at night compared with conventional one. SOLUTION: A brightness voltage for nighttime set by operating brightness adjustment means 24 and a brightness voltage for daytime are stored in EEPROM16. The brightness voltage for nighttime is read from EEPROM 16 when changed over to a map screen for nighttime according to a day/night change-over signal, while the brightness voltage for daytime is read from EEPROM 16 when changed over to a map screen for daytime, CPU 18 controls the brightness so that the brightness of liquid crystal display(LCD) 10 becomes as bright as those brightness according to the read brightness voltages. |
