Response time (flat screen)
The response time (also switching time or response time ) describes the time (in milliseconds ) that a pixel of a liquid crystal display (LCD) needs to change its state. There are two different methods with which the response time is specified: the BWT ( black-white-time or black-and-white time ) and the GTG ( gray-to-gray or gray-to-gray time).
- The shorter the response time of a display, the faster the picture can change without the picture becoming blurred (e.g. streaks when the mouse moves quickly in video games).
- This value is only important for TFT / LC displays. With tube monitors , the response time is not relevant for technical reasons, because it practically does not exist.
Black and white measurement
The time that a pixel needs to change from dark to light and back again is specified. The response time is the sum of the rise and fall times of the display.
- rise: a non-activated color point (black) changes to the fully activated state (white)
- case: a fully activated color point (white) reverts to the non-activated state
With each of these switching processes, the liquid crystals in the LCD must make the most necessary change.
- The fall time is always greater than the rise time, since each pixel still glows after switching off.
- The rise and fall values are usually given in brackets after the total time. It is customary to enter the rise value first, e.g. B. 16 (6/10).
- The measurement method for response time is defined in ISO 13406-2 .
- The manufacturer's specifications meanwhile show the far more practical gray-to-gray response time for the response time for flat screens. Black-white-black change (SWS) describes the movement of the liquid crystals in practice insufficiently, on the other hand, a change from light gray to white and back, depending on the LCD module, can take more than five times as long as SWS change. Today's fastest flat screens with a GTG (gray-to-gray) response time of 2 ms only achieve an actual response time of around 20 milliseconds despite overdrive technology.
Gray-gray measurement
