The advent of liquid-crystal display (LCD) technology has eliminated the risk for screen burn. In other, older display technologies, including cathode-ray tube (CRT), devices were susceptible to a phenomenon in which an image becomes permanently burned into the display. Known as screen burn, it was a serious problem that often led TVs, computer monitors and other display devices to an early grave.
While LCDs don’t suffer from screen burn, they are susceptible to a less-severe problem known as image persistence. But what exactly is image persistence? And how does it differ from screen burn?
Image Persistence Explained
Also known as image retention, image persistence is a phenomenon similar to that of screen burn. The main difference, however, is that image persistence is temporary, whereas screen burn is permanent. When a display device suffers from screen burn, the image becomes permanently burned into the display. You can change the channel or even turn off the display device, but the image will remain visible.
In comparison, image persistence is only temporary. After a while, the image will fade, reverting the display device back to its original, default state.
What Causes Image Persistence?
Image persistence occurs when an LCD device displays the same static image for a prolonged period. During operation, an LCD device will apply electricity to its liquid crystals, resulting in the controlled blockage of light waves. If the voltage applied to the liquid crystals doesn’t change for a prolonged period — such as 30 minutes to an hour — the liquid crystals will become fixed in that position, resulting in image persistence.
How to Prevent Image Persistence
There are two main precautions you can take to protect your LCDs from image persistence, one of which is to turn off the devices when you aren’t using them. Allowing an LCD to display the same image for a long period of time, even if it’s just a background wallpaper, increases the risk of image persistence. It keeps a fixed voltage applied to the device’s liquid crystals, thereby preventing the liquid crystals from reverting back to their default state.
In addition to turning off your LCDs when you aren’t using them, you can also prevent image persistence by changing their displayed images. If an LCD device has been displaying the same image for longer than 20 minutes, it’s probably a good idea to change it. By changing the image, the voltage applied to the device’s liquid crystals will also change. As a result, image persistence is less likely to occur.