Bildanzeigevorrichtung mit Tag- und Nachtinformationsbildanzeigen und Helligkeitssteuerungsverfahren für dieselbe

摘要

To constantly obtain a satisfactorily bright screen in both nighttime and daytime map screens and, particularly to suppress an occurrence of inversion of the screen in the nighttime map screen as compared with prior art. A nighttime bright and/or contrast voltage and a daytime bright and/or contrast voltage set by the operation of a brightness and/or contrast adjustment means 24 are stored in an EEPROM 16. When the screen is switched to the nighttime map screen in accordance with a daytime/nighttime switch signal, the nighttime bright and/or contrast voltage is read from the EEPROM 16. When the screen is switched to the daytime map screen, the daytime bright and/or contrast voltage is read from the EEPROM 16. A CPU 18 performs such a brightness and/or contrast control that the brightness and/or contrast of an LCD 10 is adjusted to a brightness and/or contrast corresponding to the read bright and/or contrast voltage.