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MONITOR, DISPLAY OR SCREEN
MONITOR, DISPLAY OR SCREEN : is a computer peripheral device capable of showing characters and/or still or moving images generated by a computer and processed by a graphics card. Computer Monitor TechnologiesA several different hardware technologies exist for displaying computer-generated output:
A modern CRT display has considerable flexibility: it can often handle a range of resolutions from 320 by 200 pixels (320×200) up to 2048 by 1536 pixels (2048×1536) or 2304 by 1440 pixels (2304×1440), with unlimited colours and a variety of refresh rates. As of 2005, the highest known maximum native resolution for any type of monitor is 3840 by 2400 pixels (3840×2400) on an LCD screen. Dot pitch measures the sharpness of a display. In general, the lower the dot pitch, (e.g. .24), the sharper the picture will appear. Early CRT-based VDUs (Visual Display Units) without graphics capabilities gained the label "glass teletypes", because of the functional similarity to their electromechanical predecessors. Black-and-white displays can only display one colour: either as on or off. Monochrome displays can show only levels of a single colour. In both cases the display usually uses green, orange (amber) or gray (white). Colour monitors may show either digital colour (turning each of the red, green and blue signals either on or off, giving eight possible colours: black, white, red, green, blue, cyan, magenta and yellow - sometimes with an extra "brightness" signal producing a total of up to 16 colours) or analog colour (red, green and blue signals vary continuously, allowing the display of any combination). Early digital monitors are sometimes known as TTLs because the voltages on the red, green and blue inputs are compatible with TTL logic chips. Later digital monitors support LVDS, or TMDS protocols. Most modern computer displays can show thousands or millions of different colours in the RGB colour space by combining red, green, and blue dots in varying intensities. With exceptions of DLP, most display technologies (especially LCD) have an inherent misregistration of the colour planes, that is, the centers of the red, green, and blue dots do not line up perfectly. Subpixel rendering depends on this misalignment; technologies making use of this include the Apple II from 1976, and more recently Microsoft ( ClearType, 1998) and XFree86 (X Rendering Extension). Moving texts can appear in italics, even when the display resolution is too low to show static italics: a fractional time delay causes an apparent corresponding shift of a fraction of a pixel. Note the sometimes disputed issue of screen emissions. Most computer monitors have analog signal relay, but some (mostly LCD screens) start supporting digital input signals. It is a common misconception that all computer monitors are digital. For several years, Televisions, composite monitors and computer displays have had significant distinction, however it has blurred as newer TVs have become versatile to accomodate these purposes. Most desktop displays use liquid crystal display (LCD) or cathode ray tube (CRT) technology, while nearly all portable computing devices such as laptops incorporate LCD technology. Because of their slimmer design and lower energy consumption, monitors using LCD technology (also called flat panel or flat screen displays) are replacing the venerable CRT on most desktops. Major manufacturers of Computer Monitor
COMPUTER MONITOR CLASSIFICATIONThe most basic one is in terms of color capabilities, which separates monitors into three classes:
An other classification, which is the most important aspect of a monitor is its screen size. the way in which the screen size is measured for CRT and LCD monitors is different. For CRT monitors, screen size is measured diagonally from outside edges of the display casing. In other words, the exterior casing is included in the measurement as seen below.
 CRT screen size For LCD monitors, screen size is measured diagonally from the inside of the beveled edge. The measurement does not include the casing as indicated in the image below
 LCD screen size Because of the differences in how CRT and LCD monitors are measured, a 17-inch LCD display is comparable to a 19-inch CRT display. For a more accurate representation of a CRT's size, find out its viewable screen size. This is the measurement of a CRT display without its outside casing. Popular screen sizes are 15, 17, 19 and 21 inches. Notebook screen sizes are smaller, typically ranging from 12 to 17 inches. As technologies improve in both desktop and notebook displays, even larger screen sizes are becoming available. For professional applications, such as medical imaging or public information displays, some LCD monitors are 40 inches or larger! Obviously, the size of the display directly affects resolution. The same pixel resolution is sharper on a smaller monitor and fuzzier on a larger monitor because the same number of pixels is spread out over a larger number of inches. An image on a 21-inch monitor with an 800x600 resolution will not appear nearly as sharp as it would on a 15-inch display at 800x600
Nearly all modern monitors accept analog signals, which is required by the VGA, SVGA, 8514/A, and other high-resolution color standards.
A program that observes a computer. For example, some monitor programs report how often another program accesses a disk drive or how much CPU time it uses. Configuration and usageMulti-headSome users use more than one monitor. The displays can operate in multiple modes. One of the most common spreads the entire desktop over all of the monitors, which thus act as one big desktop. The X Window System refers to this as "Xinerama". A monitor may also clone another monitor. Terminology:
Virtual displaysThe X Window System provides configuration mechanisms for using a single hardware monitor for rendering multiple virtual displays, as controlled (for example) with the Unix DISPLAY global variable or with the -display command option. |
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