Also called "refresh rate," it is the number of times an entire CRT screen is refreshed, or redrawn, per second. Measured in Hertz, display systems typically range from 56Hz to well over 100Hz. A minimum of 70Hz is recommended to help prevent eye strain, and many experts believe 80Hz and above is best.|
Earlier CRTs were unable to support the highest resolution and refresh rate together (the higher the resolution, the lower the refresh rate). Today, CRTs provide adequate refresh rates at all resolutions. Vertical scan frequency is not an issue with active matrix LCD displays because they do not use phosphors that have to be continuously energized. However, the data from the frame buffer is continuously sent to the LCD panel in order to display animation and video. Thus, the flat panel does have a maximum refresh rate to support motion, but not to refresh static images. Contrast with horizontal scan frequency. See interlace.