Quote:
Originally Posted by HarryT
The "refresh rate" of an LCD is a measure of how rapidly a given pixel can be updated. ...
|
With static display (e.g. text in an ereader) on an LCD screen the flicker issue is not with the LCD component but, instead, with the backlight.
Early backlit LCD displays used fluorescent illumination which flickered, but at a rather high frequency. This didn't produce any flicker that would normally be perceptible, but could become perceptible if the display was moved quickly (e.g. reading in a bouncy car, ...). The only issue I ever encountered with this type of display was when there was some loose component that vibrated at the oscillation frequency and produced an audible very high frequency squeal. My old Clie UX50 never did this though there were many posts on the boards back in the day discussing the annoyance. My travel alarm clock is quite audible when the backlight is turned on.
The more modern LCD displays use LED backlight. This, like pure LED displays can flicker. Dimming an LED display is often done by turning it on and off quickly and changing the percentage of on vs off. This results in a very high frequency flicker. You can sometimes see when this is being done by moving the LED array very very quickly and noting whether you see a smooth smear or a series of discrete images. This cycling is often done to limit the heat build up in higher power LEDs. You can often see this in LED automobile tail lights when following another car on a rough road or if you jerk your head sideways very quickly. The taillights don't smear; they are seen as a series of discrete dots.