We call screen (or monitor) the display device from the computer. There are usually two families screens:
The screens in cathode-ray tube (CRT noted for Cathode Ray Tube) fitted most desktop computers. These monitors bulky and heavy, with a high power consumption. Flat screens fitted to all laptops, personal digital assistants (PDAs), digital cameras, and that more and more computers. It is slim screens in depth (hence the name), with a lightweight and low power consumption.
LCD Screen
The monitors are often characterized by the following:
The definition: the number of dots (pixels) screen that can display the number of points is usually between 640×480 (640 points in length, 480 points in width) and 2048×1536, but higher resolutions are technically possible . The table below provides definitions recommended by the diagonal size:
Diagonal Definition
- 15 “800×600
- 17 “1024×768
- 19 “1280×1024
- 21 “1600×1200
The size: It is calculated by measuring the diagonal of the screen and is expressed in inches (one inch equals 2.54 cm). It is important not to confuse the definition of the screen and its size. Indeed a screen of a given size can display different definitions, however, generally large screens have a better definition. The standard size screens are (non-exhaustive list):
- 14 inches, a diagonal of 36 cm;
- 15 inches, a diagonal of 38 cm;
- 17 inches, a diagonal of 43 cm;
- 19 inches, a diagonal of 48 cm;
- 21 inches. is a diagonal of 53 cm;
Dot pitch: This is the distance between two phosphors; more it is small the image is more accurate. Not a mask less than or equal to 0.25 mm will provide a good comfort of use, while the screens with no mask greater than or equal to 0.28 mm will be banned.
Resolution: It determines the number of pixels per unit area (pixels per linear inch (DPI in English: Dots Per Inch, translate dots per inch). A resolution of 300 dpi means 300 columns and 300 rows of pixels on a square inch which would thus 90,000 pixels on a square inch. The reference resolution of 72 dpi gives us a pixel 1 / 72 (one inch divided by 72) is 0.353mm, corresponding to a pica (unit typographical Anglo-Saxon) .
LCD Monitor
The graphical modes
We call the graphical display of information on the screen in terms of definition and number of colors. It represents the ability of a graphics card to handle details or a screen display.
MDA : Fashion MDA (Monochrome Display Adapter), published in 1981, is the display screens providing a monochrome display text mode of 80 columns by 25 rows. Displays only ASCII characters.
CGA : The CGA mode (color graphic adapter) is published in 1981 shortly after the MDA mode with the arrival of the PC (personal computer). This graphical mode enabled:
display mode improved text that displays characters with 4 colors
display mode to display graphics pixels in 4 colors with a resolution of 320 pixels by 200 (rated 320×200)
EGA : EGA mode (Enhanced Graphics Adapter) emerged in early 1985. It displays 16 colors with a resolution of 640 by 350 pixels (640×350 noted) or more for graphics mode CGA.
XGA : In 1990, IBM introduced the XGA (Extended Graphics Array). Version 2 of this display, called XGA-2 offered a resolution of 800 x 600 in 16 million colors and 1024 x 768 with 65,536 colors.
SVGA : The mode SVGA (Super Video Graphics Array) is a graphics mode to display 256 colors at resolutions of 640×200, 640×350 and 640×480. The SVGA display also allows higher definitions such as 800×600 or 1024×768 displaying fewer colors.
VESA : To overcome the lack of standardization of graphical modes a consortium of major manufacturers of graphics cards has created (the VESA, Video Electronics Standards Association) to develop standards graphics.
SXGA : The standard SXGA (Super Extended Graphics Array) defined by the VESA consortium refers to a resolution of 1280 x 1024 in 16 million colors. This method has the characteristic of having a ration of 5:4 unlike other modes (VGA, SVGA, XGA, UXGA).
UXGA : The mode UXGA (Ultra Extended Graphics Array) defines a resolution of 1600 x 1200 with 16 million colors.
WXGA : The method WXGA (Wide eXtended Graphics Array) defines a resolution of 1280 x 800 with 16 million colors.
WSXGA : The method WSXGA (Wide Super Extended Graphics Array) defines a resolution of 1600 x 1024 with 16 million colors.
WSXGA + : The method WSXGA + (Wide Super Extended Graphics Array +) defines a resolution of 1680 x 1050 with 16 million colors.
WUXGA : The mode WUXGA (Wide Ultra Extended Graphics Array) defines a resolution of 1920 x 1200 with 16 million colors.
QXGA : The method QXGA (QXGA) defines a resolution of 2048 x 1536 with 16 million colors.
QSXGA : The method QSXGA (Quad Super Extended Graphics Array) defines a resolution of 2560 x 2048 with 16 million colors.
QUXGA : The method QUXGA (Quad Ultra eXtended Graphics Array) defines a resolution of 32000 x 2400 with 16 million colors.
Laptop Screen
