Samsung SyncMaster 550DX User Manual page 119

You can change the Safety Screen Type.
• Bar
• Eraser
• Pixel
Period
Use this function to set the execution period for each mode set in the timer.
Time
Within the set period of time specify a time for execution.
• Mode - Bar, Eraser, Pixel : 10~50 sec
Bar
This function prevents after-images on the screen by moving long black and white vertical
lines.
Eraser
Adjusting the LCD Display