| 摘要 |
<p>PURPOSE:To enable a display device to accurately catch its display content, by enabling daytime and nighttime use brightnesses to be set to an optional value while storing each data in memory so as to turn on the display device selecting the daytime or nighttime use brightness being associated with turning on and off a head light. CONSTITUTION:If a power supply is closed to a navigation device 1, a CPU6 in a controller 5 discriminates whether it is daytime or nighttime being based on a head light driving detecting sensor 7 in its detection signal of turning on or off a head light. And when the CPU6 discriminates it is the daytime, a display device, reading a data of daytime use brightness from a memory region 9a and selectively actuating a register array 10 in accordance with that data, adjusts display brightness of a cathode-ray tube (CRT)2 to the predetermined daytime use brightness. On the contrary, when the CPU6 discriminates it as nighttime, the display device, reading a data of nighttime use brightness similarly from a memory region 9b, adjusts the display brightness of the CRT2 to the predetermined nighttime use brightness in accordance with the data of the nighttime use brightness. Each display brightness for the above described daytime and nighttime use is optionally set by controlling a brightness increasing switch 3 and a brightness decreasing switch 4.</p> |
