Screen burn-in

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Burn-in on a monitor, when severe as in this "please wait" message, is visible even when the monitor is switched off. Screen burn screen off.png
Burn-in on a monitor, when severe as in this "please wait" message, is visible even when the monitor is switched off.

Screen burn-in, image burn-in, ghost image, or shadow image, is a permanent discoloration of areas on an electronic visual display such as a cathode-ray tube (CRT) in an older computer monitor or television set. It is caused by cumulative non-uniform use of the screen.

Contents

Newer liquid-crystal displays (LCDs) may suffer from a phenomenon called image persistence instead, which is not permanent.

One way to combat screen burn-in was the use of screensavers, which would move an image around to ensure that no one area of the screen remained illuminated for too long.

Causes

With phosphor-based electronic visual displays (i.e. CRT-type computer monitors, oscilloscope screens, and plasma displays), non-uniform use of specific areas, such as prolonged display of non-moving images (text or graphics), repetitive contents in gaming graphics, or certain broadcasts with tickers and flags, can create a permanent ghost-like image of these objects or otherwise degrade image quality. This is because the phosphor compounds that emit light to produce images lose their luminance with use. This wear results in uneven light output over time, and in severe cases can create a ghost image of previous content. Even if ghost images are not recognizable, the effects of screen burn are an immediate and continual degradation of image quality.

The length of time required for noticeable screen burn to develop varies due to many factors, ranging from the quality of the phosphors employed, to the degree of non-uniformity of subpixel use. It can take as little as a few weeks for noticeable ghosting to set in, especially if the screen displays a certain image constantly and displays it continually over time, for example, a menu bar at the top or bottom of the screen. In the rare case when horizontal or vertical deflection circuits fail, all output energy is concentrated to a vertical or horizontal line on the display which causes almost instant screen burn.

CRT

Screen burn on an amber CRT computer monitor. There are two separate burned-in images: one of a spreadsheet program, and another of an ASCII-art welcome screen. ScreenBurn amber (cropped).JPG
Screen burn on an amber CRT computer monitor. There are two separate burned-in images: one of a spreadsheet program, and another of an ASCII-art welcome screen.

Phosphor burn-in is particularly prevalent with monochromatic CRT screens, such as the amber or green monochrome monitors common on older computer systems and dumb terminal stations. This is partly because those screens displayed mostly non-moving images, and at one intensity: fully on. Yellow screens are more susceptible than either green or white screens because the yellow phosphor is less efficient and thus requires a higher beam current. Color screens, by contrast, use three separate phosphors (red, green, and blue), mixed in varying intensities to achieve specific colors, and in typical usage patterns such as "traditional" TV viewing (non-gaming, non-converged TV usage, non-Internet browsing, broadcasts without tickers or flags, no prolonged or permanent letterboxing) are used for operations where colors and on-screen object placement approach uniformity.

Modern CRT displays are less susceptible than older CRTs prior to the 1960s because they have a layer of aluminum behind the phosphor which offers some protection. The aluminum layer was provided to reflect more light from the phosphor toward the viewer. As a bonus, the aluminum layer also prevented ion burn of the phosphor and the ion trap, common to older monochrome televisions, [1] was no longer required. [2] [3]

Plasma, LCD, and OLED displays

Burn-in on a plasma screen at Dallas Fort Worth International Airport (2007) Plasma burn-in at DFW airport.jpg
Burn-in on a plasma screen at Dallas Fort Worth International Airport (2007)
A nearly two-year-old LCD television showing extreme burn-in of CNN's logo circa 2008 digital on-screen graphic; this television is in a McDonald's restaurant where CNN is permanently turned on and displayed throughout the business day. Emerson-McDonalds CNN Burn-In.jpg
A nearly two-year-old LCD television showing extreme burn-in of CNN's logo circa 2008 digital on-screen graphic; this television is in a McDonald's restaurant where CNN is permanently turned on and displayed throughout the business day.

Plasma displays produced until around 2007 were highly susceptible to burn-in, while LCD-type displays are rarely affected. [4] The wide variation in luminance degradation with RGB-based organic light-emitting diode (OLED) [5] will cause noticeable color drift over time (where one of the red-green-blue colors becomes more prominent). OLEDs do not need a backlight to light up; each pixel is a self-illuminating LED. The pixels on OLEDs inevitably lose their brightness over time. The longer an OLED pixel is used (illuminated), the dimmer it will appear next to a lesser-used pixel. [6]

In the case of LCDs, the physics of burn-in are different than plasma and OLED, which develop burn-in from luminance degradation of the light-emitting pixels. For LCDs, burn-in develops in some cases because pixels permanently lose their ability to return to their relaxed state after a continued static use profile. In most typical usage profiles, this image persistence in LCD is only transient.

Both plasma-type and LCD-type displays exhibit a similar phenomenon called transient image persistence, which is similar to screen burn but is not permanent. In the case of plasma-type displays, transient image persistence is caused by charge build-up in the pixel cells (not cumulative luminance degradation as with burn-in), which can be seen sometimes when a bright image that was set against a dark background is replaced by a dark background only; this image retention is usually released once a typical-brightness image is displayed and does not inhibit the display's typical viewing image quality.

Mitigation

Screensavers derive their name from their original purpose, which was an active method of attempting to stave off screen burn. By ensuring that no pixel or group of pixels was left displaying a static image for extended periods of time, phosphor luminosity was preserved. Modern screensavers can turn off the screen when not in use.

In many cases, the use of a screensaver is impractical. Most plasma-type display manufacturers include methods for reducing the rate of burn-in by moving the image slightly, [7] which does not eliminate screen burn but can soften the edges of any ghost image that does develop. [8] Similar techniques exist for modern OLED displays. For example, manufacturers of Android Wear watches with OLED displays can request that Android Wear enable "burn protection techniques" that periodically shifts the contents of the screen by a few pixels.

Other examples: Apple's iPhone X and Samsung's Galaxy series both mitigate or delay the onset of burn-in by shifting the pixels every minute or so for the battery, Wi-Fi, location, and service bars. Also, parallax scrolling may be enabled for the home screen to give icons a 3D-like effect, a setting Apple refers to as "perspective zoom". AG Neovo patented Anti-burn-in technology is also using pixel shifting to activate the pixels to move by the designed time interval to prevent the burn-in effect on LCD monitors. [9]

Google requests that when these techniques are enabled, watch face developers do not use large blocks of pixels so that different pixels are burned in with each shift, reducing the overall wear of the pixels. [10]

Some screensavers move around, such as those on DVD players or those on some television sets that move around paused video after a long period of inactivity.

Depending on the type of screen, it is sometimes possible to remedy screen burn-in through the use of remedial software and remedial devices. In the case of OLED screens on Android phones, burn-in reduction apps can display an inverted image of the navigation and status bars (which are constantly displayed and therefore the most likely elements to be burned in) to burn in an opposite pattern, resulting in a screen whose subpixels have more even luminosity and therefore less visible burn-in artifacts. [11]

Historical notes

The most prevalent burn-in image on early televisions was said to be that of the RCA Indian-head test pattern, which would often follow the formal television station sign-off. This was due to the viewer leaving the television set on at the end of the day, which was not recommended by the television manufacturers.[ citation needed ]

Related Research Articles

<span class="mw-page-title-main">Cathode-ray tube</span> Vacuum tube often used to display images

A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms on an oscilloscope, a frame of video on an analog television set (TV), digital raster graphics on a computer monitor, or other phenomena like radar targets. A CRT in a TV is commonly called a picture tube. CRTs have also been used as memory devices, in which case the screen is not intended to be visible to an observer. The term cathode ray was used to describe electron beams when they were first discovered, before it was understood that what was emitted from the cathode was a beam of electrons.

<span class="mw-page-title-main">Computer monitor</span> Computer output device

A computer monitor is an output device that displays information in pictorial or textual form. A discrete monitor comprises a visual display, support electronics, power supply, housing, electrical connectors, and external user controls.

<span class="mw-page-title-main">Phosphor</span> Luminescent substance

A phosphor is a substance that exhibits the phenomenon of luminescence; it emits light when exposed to some type of radiant energy. The term is used both for fluorescent or phosphorescent substances which glow on exposure to ultraviolet or visible light, and cathodoluminescent substances which glow when struck by an electron beam in a cathode-ray tube.

<span class="mw-page-title-main">Screensaver</span> Computer program that blanks the screen or fills it with moving images

A screensaver is a computer program that blanks the display screen or fills it with moving images or patterns when the computer has been idle for a designated time. The original purpose of screensavers was to prevent phosphor burn-in on CRT or plasma computer monitors. Though most modern monitors are not susceptible to this issue, screensaver programs are still used for other purposes. Screensavers are often set up to offer a basic layer of security by requiring a password to re-access the device. Some screensaver programs also use otherwise-idle computer resources to do useful work, such as processing for volunteer computing projects.

<span class="mw-page-title-main">Plasma display</span> Type of flat-panel display

A plasma display panel is a type of flat-panel display that uses small cells containing plasma: ionized gas that responds to electric fields. Plasma televisions were the first large flat-panel displays to be released to the public.

<span class="mw-page-title-main">Flat-panel display</span> Electronic display technology

A flat-panel display (FPD) is an electronic display used to display visual content such as text or images. It is present in consumer, medical, transportation, and industrial equipment.

<span class="mw-page-title-main">Display device</span> Output device for presentation of information in visual form

A display device is an output device for presentation of information in visual or tactile form. When the input information that is supplied has an electrical signal the display is called an electronic display.

<span class="mw-page-title-main">Display resolution</span> Width and height of a display in pixels

The display resolution or display modes of a digital television, computer monitor, or other display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by different factors in cathode ray tube (CRT) displays, flat-panel displays and projection displays using fixed picture-element (pixel) arrays.

Flicker is a visible change in brightness between cycles displayed on video displays. It applies to the refresh interval on cathode ray tube (CRT) televisions and computer monitors, as well as plasma computer displays and televisions.

A television set or television receiver is an electronic device for the purpose of viewing and hearing television broadcasts, or as a computer monitor. It combines a tuner, display, and loudspeakers. Introduced in the late 1920s in mechanical form, television sets became a popular consumer product after World War II in electronic form, using cathode ray tube (CRT) technology. The addition of color to broadcast television after 1953 further increased the popularity of television sets in the 1960s, and an outdoor antenna became a common feature of suburban homes. The ubiquitous television set became the display device for the first recorded media for consumer use in the 1970s, such as Betamax, VHS; these were later succeeded by DVD. It has been used as a display device since the first generation of home computers and dedicated video game consoles in the 1980s. By the early 2010s, flat-panel television incorporating liquid-crystal display (LCD) technology, especially LED-backlit LCD technology, largely replaced CRT and other display technologies. Modern flat panel TVs are typically capable of high-definition display and can also play content from a USB device. Starting in the late 2010s, most flat panel TVs began to offer 4K and 8K resolutions.

<span class="mw-page-title-main">LCD television</span> Television set with liquid-crystal display

A liquid-crystal-display television is a television set that uses a liquid-crystal display to produce images. It is by far the most widely produced and sold type of television display. LCD TVs are thin and light, but have some disadvantages compared to other display types such as high power consumption, poorer contrast ratio, and inferior color gamut.

<span class="mw-page-title-main">Field-emission display</span>

A field-emission display (FED) is a flat panel display technology that uses large-area field electron emission sources to provide electrons that strike colored phosphor to produce a color image. In a general sense, an FED consists of a matrix of cathode ray tubes, each tube producing a single sub-pixel, grouped in threes to form red-green-blue (RGB) pixels. FEDs combine the advantages of CRTs, namely their high contrast levels and very fast response times, with the packaging advantages of LCD and other flat-panel technologies. They also offer the possibility of requiring less power, about half that of an LCD system. FEDs can also be made transparent.

An output device is any piece of computer hardware that converts information or data into a human-perceptible form or, historically, into a physical machine-readable form for use with other non-computerized equipment. It can be text, graphics, tactile, audio, or video. Examples include monitors, printers, speakers, headphones, projectors, GPS devices, optical mark readers, and braille readers.

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

<span class="mw-page-title-main">Image persistence</span> Temporary effect on LCD and plasma screens

Image persistence, or image retention, is the LCD and plasma display equivalent of screen burn-in. Unlike screen burn, the effects are usually temporary and often not visible without close inspection. Plasma displays experiencing severe image persistence can result in screen burn-in instead.

<span class="mw-page-title-main">Large-screen television technology</span> Technology rapidly developed in the late 1990s and 2000s

Large-screen television technology developed rapidly in the late 1990s and 2000s. Prior to the development of thin-screen technologies, rear-projection television was standard for larger displays, and jumbotron, a non-projection video display technology, was used at stadiums and concerts. Various thin-screen technologies are being developed, but only liquid crystal display (LCD), plasma display (PDP) and Digital Light Processing (DLP) have been publicly released. Recent technologies like organic light-emitting diode (OLED) as well as not-yet-released technologies like surface-conduction electron-emitter display (SED) or field-emission display (FED) are in development to supersede earlier flat-screen technologies in picture quality.

Display motion blur, also called HDTV blur and LCD motion blur, refers to several visual artifacts that are frequently found on modern consumer high-definition television sets and flat panel displays for computers.

<span class="mw-page-title-main">Monochrome monitor</span> Type of CRT computer monitor

A monochrome monitor is a type of computer monitor in which computer text and images are displayed in varying tones of only one color, as opposed to a color monitor that can display text and images in multiple colors. They were very common in the early days of computing, from the 1960s through the 1980s, before color monitors became widely commercially available. They are still widely used in applications such as computerized cash register systems, owing to the age of many registers. Green screen was the common name for a monochrome monitor using a green "P1" phosphor screen; the term is often misused to refer to any block mode display terminal, regardless of color, e.g., IBM 3279, 3290.

Electrically operated display devices have developed from electromechanical systems for display of text, up to all-electronic devices capable of full-motion 3D color graphic displays. Electromagnetic devices, using a solenoid coil to control a visible flag or flap, were the earliest type, and were used for text displays such as stock market prices and arrival/departure display times. The cathode ray tube was the workhorse of text and video display technology for several decades until being displaced by plasma, liquid crystal (LCD), and solid-state devices such as thin-film transistors (TFTs), LEDs and OLEDs. With the advent of metal–oxide–semiconductor field-effect transistors (MOSFETs), integrated circuit (IC) chips, microprocessors, and microelectronic devices, many more individual picture elements ("pixels") could be incorporated into one display device, allowing graphic displays and video.

The following table compares cathode-ray tube (CRT), liquid-crystal display (LCD), plasma and organic light-emitting diode (OLED) display device technologies. These are the most often used technologies for television and computer displays. A less detailed comparison of a wider variety of display technologies is available at Comparison of display technology.

References

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  3. Dudding, R.W. (1951). "Aluminium backed screens for cathode ray tubes". Journal of the British Institution of Radio Engineers. 11 (10): 455–462. doi:10.1049/jbire.1951.0057.
  4. Gordon, Whitson. "Is "Burn-In" Still an Issue on TVs and Monitors?". Lifehacker. Retrieved 20 September 2018.
  5. "DuPont claims OLED record fit for TV apps". EE Times. 12 May 2010. Retrieved 4 June 2021.
  6. "Image Burn-In". Newhaven Display. Retrieved 9 August 2022.
  7. "Plasma TV Screen Burn-In: Is It Still a Problem?". Plasma TV Buying Guide. Retrieved 26 July 2012.
  8. Plasma TV Features - at the Wayback Machine (archived 21 June 2015)
  9. "Fix LCD Monitor Burn In Effect – Anti-Burn-in™ Technology". AG Neovo.
  10. "Watch Faces for Android Wear". Android Developers. Retrieved 15 March 2016.
  11. AMOLED Burn-in Fixer - Android Apps on Google Play at the Wayback Machine (archived 31 December 2016)