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Presentation 40 – Displays and Resolution. Objectives. At the end of this presentation, you will be able to:. Define each of the following in terms of resolution: QXGA, UXGA, SXGA, XGA, SVGA, VGA, EGA, and CGA.
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Objectives At the end of this presentation, you will be able to:
Define each of the following in terms of resolution: QXGA, UXGA, SXGA, XGA, SVGA, VGA, EGA, and CGA. • Define the following display terms: Screen size, aspect ratio, resolution, interlace, refresh rate, dot pitch, and pixel. • Explain how the number of pixels affects the size of the letters displayed on a screen. • Explain the difference between the triad pattern and bar pattern of phosphor used on the face of a CRT.
Measuring Screen size Screen size is measured diagonally.
Vertical Size Horizontal Size Horizontal Size Vertical Size Aspect Ratio =
Super VGA (SVGA) • The standard for PCs and monitors. • Popular SVGA formats include: • 800 by 600 pixels • 1024 by 768 pixels • 1280 by 1024 pixels • The higher the resolution, the finer the detail displayed. • The higher the resolution; the more information displayed.
Video Graphics Array (VGA) • Resolution of 640 by 480 pixels. • Introduced in 1987 by IBM as the PS/2 • First to use analog video outputs. • First to use square pixels so vertical and horizontal lines have the same thickness. • Replaced by SVGA in most applications.
Enhanced Graphics Adapter (EGA) • Resolution of 640 by 350 pixels. • Introduced by IBM in 1984.
Color Graphics Adapter (CGA) • Resolution of 320 by 200 pixels. • Introduced with the original IBM PC in 1981. • The first of the IBM color adapters for the PC.
Evolution of Video Display Adapters • 1981 CGA 320 by 200 • 1984 EGA 640 by 350 • 1987 VGA 640 by 480 • 1992 SGA 800 by 600 • XGA 1024 by 768 • SXGA 1280 by 1024 • UXGA 1600 by 1200 • QXGA 2048 by 1536
SVGA VGA
Video Mode changes things... • Screen resolution • Screen refresh rate • Amount of video RAM needed
The Screen Resolution Resolution Colors 640 x 480 16, 256, 32K, 64K, 16 Million 800 x 600 256, 32K, 64K, 16 Million 1024 x 768 256, 32K, 64K, 16 Million 1280 x 1024 256, 32K, 64K, 16 Million 1600 x 1200 256, 32K, 64K, 16 Million 2048 x 1536 256, 32K, 64K, 16 Million
The Screen Refresh Rate 43 Hz 60 Hz 72 Hz 75 Hz
Interlaced Mode 60 Hz
Resolution vs. Monitor Size Monitor Size 13-inch 14-inch 15-inch 17-inch 21-inch Max Resolution 640 x 480 800 x 600 800 x 600 1024 x 768 1600 x 1200
The Video Palette 0000 0001 0010 Foreground Color code 0110 0011 0100 0101 Background Color code 0001 0110 0111 1110 1111
Amount of VRAM Needed Mode Rows x Columns Colors Memory Text 24 x 80 16 x 2 5888 bytes Graphics 640 x 480 16 256K bytes Graphics 640 x 480 256 512K bytes Graphics 640 x 480 65K 1024K bytes Graphics 640 x 480 16 Million 1024K bytes Graphics 800 x 600 16 256K bytes Graphics 800 x 600 256 512K bytes Graphics 800 x 600 65K 1024K bytes Graphics 800 x 600 16 Million 2048K bytes Graphics 1024 x 768 16 512K bytes Graphics 1024 x 768 256 1024K bytes Graphics 1024 x 768 65K 2048K bytes Graphics 1024 x 768 16 Million 4096K bytes continued...
Amount of VRAM Needed Mode Rows x Columns Colors Memory Graphics 1280 x 1024 16 1024K bytes Graphics 1280 x 1024 256 2048K bytes Graphics 1280 x 1024 65K 4096K bytes Graphics 1280 x 1024 16 Million 4096K bytes Graphics 1600 x 1200 16 1024K bytes Graphics 1600 x 1200 256 2048K bytes Graphics 1600 x 1200 65K 4096K bytes Graphics 1600 x 1200 16 Million 8192K bytes
Dot Pitch and Pixels Phosphor Color Triad Pixel Dot Pitch 0.26 mm, 0.28mm, 0.31 mm or 0.34 mm
Pixel Pixel
The Effect of Pixel Size 10 x 12 pixels 6 x 8 pixels
Level of Illumination Fully Half None
Superimposing Images
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The LCD Display • The LCD is rapidly becoming the most popular display technology. • LCDs offer several advantages: • Flat display area • Low power • Larger viewable area • Take up less space • LCD displays do not: • Emit electromagnetic radiation • Have high voltages present in the chassis.
Disadvantages • Generally more expensive than comparable CRT display. • Resolutions can be less than a comparable CRT.
Available for both desktop and notebook. • Two common LCD technologies: • Active-Matrix Analog is common on smaller low cost displays • Active-Matrix Digital is used in larger high-end displays.
LCDs use a unique material called liquid crystal. • Liquid Crystal has properties similar to water and crystal. • By applying a voltage, the amount of light can be controlled. • Color LCDs use color filters to create the color display.
Transparent GlassPlate Liquid Crystal Molecules Transparent Electrode
Components of the color LCD display include: • A liquid crystal panel • A backlight as a light source • A thin film transistor (TFT) array • Polarizing filers on both sides of the display.
Consider before selecting an LCD • More difficult to switch resolutions. • Analog LCD panels can use existing video card and connector. • LCD may not have sufficient color depth. • Many don’t react as quickly as CRTs.
Large screen LCD monitors are becoming a real display option. • LCD monitors offer several advantages: • Larger effective viewing area • Produce a higher precision image • Flexible mounting options • No electromagnetic emissions.
Is an LCD suitable? • Evaluate panel at native and other required resolutions. • Does existing video card support required features? • Support for analog and DVI inputs? • Contrast ratio high enough?