Sketch of some common display technologies' temporal behaviour

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Rear Projection TVs

This is a comparison of various properties of different display technologies. more...

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General characteristics

Temporal characteristics

Different display technologies have vastly different temporal characteristics, leading to claimed perceptual differences for motion, flicker etc.

The figure shows a sketch of how different technologies present a single white/gray frame. Time and intensity is not to scale. Notice that some have a fixed intensity, while the illuminated period is variable. This is a kind of pulse-width modulation. Others can vary the actual intensity in response to the input signal.

DLPs use a kind of "chromatic multiplex" in which each color is presented serially. The intensity is varied by modulating the "on" time of each pixel within the time-span of one color.

LCDs have a constant (backlit) image, where the intensity is varied by blocking the light shining through the panel.

CRTs use an electron beam, scanning the display, flashing a lit image. If interlacing is used, a single full-resolution image results in two "flashes".

Plasma displays modulate the "on" time of each sub-pixel, similar to DLP.

Movie theaters use a mechanical shutter to "flash" the same frame 2 or 3 times, increasing the flicker frequency to make it less perceptible to the human eye.