Frame rate control

Frame rate control (FRC) is a method for achieving greater color depth in TFT LCD displays.

Older TN panels represented colors using only 6 bits per RGB color, or 18 bit in total, and were unable to display the 16.7 million color shades (24-bit truecolor) that display devices like graphics cards, game consoles, tablet computers and set-top boxes can output. Instead, they could use a dithering method that combines adjacent pixels to simulate the desired shade. As of 2021, most TN panels are capable of displaying 24-bit color without any form of dithering.

FRC is a form of temporal dithering which cycles between different color shades with each new frame to simulate an intermediate shade. This can create a potentially noticeable 30 Hz flicker. FRC tends to be most noticeable in darker tones, while dithering appears to make the individual pixels of the LCD visible.[1] Modern TFT panels (as of 2020) often use FRC to display 30-bit deep color or HDR10 with 24-bit color panels.[2][3]

This method is similar in principle to field-sequential color system by CBS and other sequential color methods such as used in Digital Light Processing (DLP).

The demonstration on the right mixes cyan and green-cyan statically (top) and by rapidly alternating the colors (bottom). The size of the thumbnail has been reduced to reduce the flicker people may experience in their peripheral vision while reading the article. In a monitor that uses FRC the alternating colors would be more similar, reducing the flicker effect.