BRIGHTNESS CONTROL SYSTEM OF MULTIWINDOW DISPLAY DEVICE

PURPOSE:To make the contents of an active window easy to see on a screen where plural windows are displayed by decreasing the brightness of a part other than the active window displayed on the screen automatically. CONSTITUTION:Contents to be displayed in the windows 101 - 103 are stored in a VRAM are read out thereafter at a constant period to generate a display signal 8, which is displayed on the screen 100 by the screen scanning of the display device 10. At this time, a current scanning position storage part 1 holds the current scanning position on the screen 100 and outputs its position information 5 to a position comparison part 3, and an active window display position storage part 2 holds the display position of the active window 101 among the displayed windows and outputs its position information 6 to the comparison part 3, which compares the pieces of information 5 and 6 to generate a brightness control signal 7. Then a brightness control part 4 processes the signal 8 according to the signal 7 and lowers the brightness of the area other than the active window on the screen 100.