PENGUIN SCREENSAVER FOR LARGE SCREENS PASSWORD
They usually feature moving images or patterns and sometimes sound effects.Īs screensavers are generally expected to activate when users are away from their machines, many screensavers can be configured to ask users for a password before permitting the user to resume work. Primarily these are for decorative/entertainment purposes, or for password protection. While modern screens are not susceptible to the issues discussed above, screensavers are still used. Gnome-screensaver has an option for password protection LCD computer monitors, including the display panels used in laptop computers, are not susceptible to burn-in because the image is not directly produced by phosphors (although they can suffer from a less extreme and usually non-permanent form of image persistence). Later CRTs were much less susceptible to burn-in than older models due to improvements in phosphor coatings, and because modern computer images are generally lower contrast than the stark green- or white-on-black text and graphics of earlier machines. In these applications, burn-in can be prevented by shifting the position of the display contents every few seconds, or by having a number of different images that are changed regularly. Blanking the screen is out of the question as the machine would appear to be out of service. Older machines designed without burn-in problems taken into consideration often display evidence of screen damage, with images or text such as "Please insert your card" (in the case of ATMs) visible even when the display changes while the machine is in use. Screen-saver programs were designed to help avoid these effects by automatically changing the images on the screen during periods of user inactivity.įor CRTs used in public, such as ATMs and railway ticketing machines, the risk of burn-in is especially high because a stand-by display is shown whenever the machine is not in use. Cathode ray televisions, oscilloscopes and other devices that use CRTs are all susceptible to phosphor burn-in, as are plasma displays to some extent.
When the same image is displayed on a CRT screen for long periods, the properties of the exposed areas of the phosphor coating on the inside of the screen gradually and permanently change, eventually leading to a darkened shadow or "ghost" image on the screen, called a screen burn-in. Purpose Screen protection īefore the advent of LCD screens, most computer screens were based on cathode ray tubes (CRTs).
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