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Computer monitor

Computer monitor. Presentation for the instructor /Miss- Rasha A tala. Student/ Mahmoud omar shehada. 2-Monitors in the past. 1 - Over view. 3-Types of monitor. 5-Problems. 4- Performance measurements. 6- Additional features. Monitors in the past.

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Computer monitor

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  1. Computer monitor Presentation for the instructor /Miss- RashaAtala Student/ Mahmoudomarshehada

  2. 2-Monitors in the past 1 - Over view 3-Types of monitor 5-Problems 4- Performance measurements 6- Additional features

  3. Monitors in the past • The video display terminal, or VDT, marked the early days of computer monitors. These VDTs included a screen and attached keyboard linked to a larger computer by a serial connection. Because VDTs required a connection to a larger computer, they were often referred to as "dumb terminals." Dumb terminals displayed text only in two colors, usually black and green. The Apple II and first game machines began using a television CRT.

  4. Over view A monitor or display (sometimes called a visual display unit) is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure. The display device in modern monitors is typically a thin film transistor liquid crystal display (TFT-LCD) thin panel, while older monitors use a cathode ray tube about as deep as the screen size. Originally computer monitors were used for data processing and television receivers for entertainment; increasingly computers are being used both for data processing and entertainment. Displays exclusively for data use tend to have an aspect ratio of 4:3; those used also (or solely) for entertainment are usually 16:9 widescreen, Sometimes a compromise is used, e.g. 16:10[1].

  5. A 19-inch LG flat-panel LCD monitor.

  6. IBM PC with green monochrome display.

  7. Apple II – 1977

  8. Apple III – 1980

  9. Car monitor

  10. Screen size Main articles: Viewable image size and Computer display .standard

  11. Performance measurements • Viewable image size • Aspect ratios • Display resolution • Dot pitch • widescreen • Refresh rate • Response time • Quality of the colors • pixels • Power consumption • Viewing angle

  12. A CRT display device uses a glass tube • An LCD manipulates light within a layer of liquid crystal cells • Plasma screen technology illuminates lights arranged in a panel-like screen

  13. Problems Phosphor burn-in: Phosphor burn-in is localized aging of the phosphor layer of a CRT screen where it has displayed a static image for long periods of time. This results in a faint permanent image on the screen, even when turned off. In severe cases, it can even be possible to read some of the text, though this only occurs where the displayed text remained the same for years. Burn-in is most commonly seen in the following applications: Point-of-service applications Arcade games Security monitors Screen savers were developed as a means to avoid burn-in, which was a widespread problem on IBM Personal Computer monochrome monitors in the 1980s. Monochrome displays are generally more vulnerable to burn-in because the phosphor is directly exposed to the electron beam while in color displays, the shadow mask provides some protection. Although still found on newer computers, screen savers are not necessary on LCD monitors. Phosphor burn-in can be "fixed" by running a CRT with the brightness at 100% for several hours, but this merely hides the damage by burning all the phosphor evenly. CRT rebuilders can repair monochrome displays by cutting the front of the picture tube off, scraping out the damaged phosphor, replacing it, and resealing the tube. Color displays can theoretically be repaired, but it is a difficult, expensive process and is normally only done on professional broadcasting monitors (which can cost up to $10,000).

  14. Plasma burn-in • Burn-in re-emerged as an issue with early plasma displays, which are more vulnerable to this than CRTs. Screen savers with moving images may be used with these to minimize localized burn. Periodic change of the color scheme in use also helps. • Glare • Glare is a problem caused by the relationship between lighting and screen or by using monitors in bright sunlight. Matte finish LCDs and flat screen CRTs are less prone to reflected glare than conventional curved CRTs or glossy LCDs, and aperture grille CRTs, which are curved on one axis only and are less prone to it than other CRTs curved on both axes. • If the problem persists despite moving the monitor or adjusting lighting, a filter using a mesh of very fine black wires may be placed on the screen to reduce glare and improve contrast. These filters were popular in the late 1980s[citation needed]. They do also reduce light output. • A filter above will only work against reflective glare; direct glare (such as sunlight) will completely wash out most monitors' internal lighting, and can only be dealt with by use of a hood or transreflective LCD. • Color misregistration • With exceptions of correctly aligned video projectors and stacked LEDs, most display technologies, especially LCD, have an inherent misregistration of the color channels, that is, the centers of the red, green, and blue dots do not line up perfectly. Sub-pixel rendering depends on this misalignment; technologies making use of this include the Apple II from 1976[3], and more recently Microsoft (ClearType, 1998) and XFree86 (X Rendering Extension). • Incomplete spectrum • RGB displays produce most of the visible color spectrum, but not all. This can be a problem where good color matching to non-RGB images is needed. This issue is common to all monitor technologies that use the RGB model. Recently, Sharp introduced a four-color TV (red, green, blue, and yellow) to improve on this.

  15. Additional features • Power saving • Most modern monitors will switch to a power-saving mode if no video-input signal is received. This allows modern operating systems to turn off a monitor after a specified period of inactivity. This also extends the monitor's service life. • Some monitors will also switch themselves off after a time period on standby. • Most modern laptops provide a method of screen dimming after periods of inactivity or when the battery is in use. This extends battery life and reduces wear. • Integrated accessories Glossy screen Directional screen • Narrow viewing angle screens are used in some security conscious applications. • Autopolyscopic screen • A directional screen which generates 3D images without headgear. • Touch screen • These monitors use touching of the screen as an input method. Items can be selected or moved with a finger, and finger gestures may be used to convey commands. The screen will need frequent cleaning due to image degradation from fingerprints. • Tablet screens

  16. Thank you for attention

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