phosphor fatigue ==>
<tool> A program which displays either a completely black image or a
constantly changing image on a computer monitor to prevent a stationary image
from "burning" into the phosphor of the screen. Screen savers usually start
automatically after the computer has had no user input for a preset time. Some
screen savers come with many different modules, each giving a different effect.
Approximately pre-1990, many cathode ray tubes, in TVs, computer monitors or
elsewhere, were prone to "burn-in"; that is, if the same pattern (e.g., the
WordPerfect status line; the Pong score readout; or a TV channel-number display)
were shown at the same position on the screen for very long periods of time, the
phosphor on the screen would "fatigue" and that part of the screen would seem
greyed out, even when the CRT was off.
Eventually CRTs were developed which were resistant to burn-in (and which
sometimes went into sleep mode after a period of inactivity); but in the
meantime, solutions were developed: home video game systems of the era (e.g.,
Atari 2600s) would, when not being played, change the screen every few seconds,
to avoid burn-in; and computer screen saver programs were developed.
The first screen savers were simple screen blankers - they just set the screen
to all black, but, in the best case of creeping featurism ever recorded, these
tiny (often under 1K long) programs grew without regard to efficiency or even
basic usefulness. At first, small, innocuous display hacks (generally on an
almost-black screen) were added. Later, more complex effects appeared, including
animations (often with sound effects!) of arbitrary length and complexity.
Along the way, avoiding repetitive patterns and burn-in was completely forgotten
and "screen savers" such as Pointcast were developed, which make no claim to
save your monitor, but are simply bloated browsers for push media which
self-start after the machine has been inactive for a few minutes.
screen popping « screen reader « screen refresh «
screen saver » screen scraper » screen server »