1. Hardware Fundamentals Week 7 – Lesson 1 24/05/2015Hardware Fundamentals1

2. Learning Outcomes  Define Visual Display Unit (VDU) characteristics: Pixel, Resolution, Screen size and Refresh Rate  Describe briefly the purpose of video standards.  Discuss different video standards and high-definition television standards  Define Cathode Ray Tube (CRT) characteristics: Dot pitch, Black and White versus Colour monitors, Two types of pixel shapes, Interlaced, Non-interlaced and Radiation  Describe CRT operation, LCD operation, and Plasma operation  Define Liquid Crystal Display (LCD) characteristics: Matrix, Passive matrix and Active matrix  Define Plasma characteristics  Compare CRT, LCD and Plasma displays  Is CRT still the best for high-definition TV?  Surface-conduction Electron-emitter Display (SED) for the future 24/05/2015Hardware Fundamentals2

3. Visual Display Unit (VDU) characteristics 24/05/2015Hardware Fundamentals3

4. Pixel  Picture element  The smallest thing that can be turned on or off to produce an image  A dot  Anything you see on a computer screen is a combination of these dots or pixels 24/05/2015Hardware Fundamentals4

5. Resolution  Total number of pixels displayed  Resolution = # pixels across * # lines displayed 24/05/2015Hardware Fundamentals5

6. If there are 1024 pixels across and 768 lines displayed, what is the resolution? Resolution 1024 * 768 = 786,432 24/05/2015Hardware Fundamentals6

7. Screen size  Measured diagonally across the front face  Measured in inches  Viewable areas may be less  Typical sizes: (12.1”), 14”, (14.1”), 15”, (15.4”), 17”, 19”, 20”, 21”, 22”, 24”, 27” 24/05/2015Hardware Fundamentals7

8. Refresh rate  How often the screen is refreshed or redrawn  Screen needs to be refreshed regularly as the phosphors stop glowing and the image to be displayed changes  Measured in Hertz (i.e.. Hz) per second 24/05/2015Hardware Fundamentals8

9. Video standards 24/05/2015Hardware Fundamentals9

10. Video standards  Defines the resolution and colors for displays  The standard used, will be determined by the monitor and the video adapter card  For high-resolution displays:  Quad – is a mode with four times as many pixels (twice the width and twice the height)  Hex – is a mode with 16 times as many pixels (four times the width and four times the height) 24/05/2015Hardware Fundamentals10

11. Video standards NameResolutionTotal pixels Colour Graphics Adapter (CGA)320 x 20064,000 Enhanced Graphics Adapter (EGA) 640 x 350224,000 Video Graphics Array (VGA)640 x 480307,200 Super VGA (SVGA)800 x 600480,000 eXtended Graphics Array (XGA)1024 x 768786,432 Super XGA (SXGA)1280 x 10241,310,720 Ultra XGA (UXGA)1600 x 12001,920,000 Quad XGA (QXGA)2048 x 15363,145,728 Quad SXGA (QSXGA)2560 x 20485,242,880 Quad Ultra XGA (QUXGA)3200 x 24007,680,000 Hex Super XGA (HSXGA)5120 X 409620,971,520 Hex Ultra XGA (HUXGA)6400 X 480030,720,000 24/05/2015Hardware Fundamentals11

12. High Definition Television standards NameResolutionTotal pixels Wide Quarter VGA (WQVGA) 400 x 24096,000 Wide VGA (WVGA)852 x 480408,960 Wide XGA (WXGA)1366 x 7681,049,088 Wide Super XGA (WSXGA)1600 x 10241,638,400 Wide Ultra XGA (WUXGA)1920 x 12002,304,000 Wide Quad XGA (WQXGA)2560 x 16004,096,000 Wide Quad Super XGA (WQSXGA) 3200 X 20486,553,600 Wide Quad Ultra XGA (WQUXGA) 3840 X 24009,216,000 Wide Hex Super XGA (WHSXGA) 6400 X 409626,214,400 Wide Hex Ultra XGA (WHUXGA) 7680 X 480036,864,000 24/05/2015Hardware Fundamentals12

13. Three types of monitors  Cathode Ray Tube (CRT)  Liquid Crystal Display (LCD)  Plasma 24/05/2015Hardware Fundamentals13

14. Three types of monitors 24/05/2015Hardware Fundamentals14

15. CRT characteristics and operation 24/05/2015Hardware Fundamentals15

16. Dot pitch  Spacing between each pixel  Typically 0.24mm 24/05/2015Hardware Fundamentals16

17. Black and White versus Color monitors  Black and White monitor  Use white pixels  Made up of one phosphor  Colour monitor  Uses three primary colours: Red; Green; and Blue (RGB)  Made up of three phosphors, so close that the human eye sees the image as one single pixel 24/05/2015Hardware Fundamentals17

18. Two types of pixel shapes  Triad  Three electron guns arranged with overlapping circles in a triangle  Circular holes in shadow mask  Used in smaller screens (e.g. monitors)  Trinitron  Three electron guns arranged in one line  Three parallel slots  Oval slots in shadow mask  Used in large screens (e.g. televisions) 24/05/2015Hardware Fundamentals18

19. Interlaced  Image on screen is created in two halves  First the odd numbered lines then the even numbered lines  Cheaper  Produce a flickering image and jerky video motion  Mostly found on older PC monitors 24/05/2015Hardware Fundamentals19

20. Non-interlaced  Entire screen is created in one go  Less flicker  Smoother video motion  More commonly found 24/05/2015Hardware Fundamentals20

21. 24/05/2015Hardware Fundamentals21

22. CRT operation (1 of 2)  Electron gun generates an electron beam  The yoke is an electromagnet. Varying the magnetism in the yoke causes the electron beam to focus in particular areas of the screen  The shadow mask is a metal screen with holes in it. The metal blocks the electron beam but the holes will let the electron beam through when it will strike a pixel, and only one pixel. Makes sure the image is sharp  The phosphor screen is made up of the phosphors that glow when hit by the electron beam. An image is formed by turning on some phosphors but not others. 24/05/2015Hardware Fundamentals22

23. 24/05/2015Hardware Fundamentals23

24. CRT operation (2 of 2)  The electron beam sweeps over the phosphor screen, making some phosphors glow, so fast that the user sees a stable image on the screen.  Other components such as the panel glass, funnel glass and the inner magnetic shield provide the structure of the CRT 24/05/2015Hardware Fundamentals24

25. Radiation  Whenever an electric current passes through a conductor (such as a wire or a copper track on a circuit board) it gives off an electro magnetic field  The electron gun, electromagnet and coil inside a CRT monitor produce magnetic fields that radiate from the monitor  Most of this radiation is exposed from the rear of the monitor 24/05/2015Hardware Fundamentals25

26. LCD characteristics and operation 24/05/2015Hardware Fundamentals26

27. Matrix  A two dimensional array; that is, an array of rows and columns  The background area of colour display 24/05/2015Hardware Fundamentals27

28. Two methods are used to apply charges to liquid crystal cells  Passive Matrix  Active Matrix 24/05/2015Hardware Fundamentals28

29. Passive Matrix  Thin Film Transistor (TFT) for each row and column  Cheaper  Use relatively few electrodes arranged along the edges of the liquid crystal layer and rely on timing to be sure the correct cells are charged  The charges in the cells fade quickly, causing a faded look 24/05/2015Hardware Fundamentals29

30. Active Matrix  Individual TFT’s for each cell/sub pixel (i.e. RGB)  Brighter  Wider viewing angle  Expensive  70% failure rate at manufacturing stage  Provide a more precise and stronger charge, creating more vivid colours 24/05/2015Hardware Fundamentals30

31. LCD operation (1 of 2)  Light emanating from a fluorescent panel behind a computers display panel spreads out in waves that vibrate in all directions  A polarising filter in front of the light panel lets through only the light waves that are vibrating more or less horizontally  In a layer of liquid crystal cells – there is one for each colour (RGB)  The light emerging from each liquid crystal cell passes through one of the three colour filters – RGB – that are arranged close to each other 24/05/2015Hardware Fundamentals31

32. LCD operation (2 of 2)  The coloured beams of light pass through a second polarising filter that is aligned to let pass only those light waves that are vibrating more or less vertically  The light that passed through a liquid crystal to which a full electrical charge was applied is now oriented perfectly to pass through the second filter.  Any light that was not twisted at all when passed through the liquid crystals is now blocked completely 24/05/2015Hardware Fundamentals32

33. Plasma characteristics and operation 24/05/2015Hardware Fundamentals33

34. Plasma characteristics  Thin display, less than 2 inches thick  Flat display  Can be hang on the wall like a painting  Plasma display is brighter than LCD  Wider viewing angle than LCD (160 degrees)  Larger sizes than LCD  More expensive than LCD 24/05/2015Hardware Fundamentals34

35. Plasma operation (1 of 3)  Two sets of electrodes  Address Electrodes are positioned vertically in the rear of the display  Display Electrodes are positioned horizontally in the front of the pixels  These electrodes run through layers of glass and magnesium oxide, which protect and insulate the electrodes from each other  Pixels are called cells, these are depressed in ridges called ribs  The ribs separate the cells  Trapped inside each cell is a mixture of xenon and neon gases 24/05/2015Hardware Fundamentals35

36. Plasma operation (2 of 3)  Illuminate tiny coloured fluorescent lights to form an image  Each pixel is made up of three fluorescent lights: a red light; a green light; and a blue light  Display varies the intensities of the different lights to produce a full range of colours  The central element in a fluorescent light is a plasma, a gas make up of free-flowing ions (electrically charge atoms) and electrons (negatively charged particles) 24/05/2015Hardware Fundamentals36

37. Plasma operation (3 of 3)  When an electrical current runs through a plasma, negatively charged particles are rushing toward the positively charged areas of the plasma, and the positively charged particles are rushing toward the negatively charged areas  In this mad rush, particles are constantly bumping into each other  These collisions excite the gas atoms in the plasma, causing the plasma screens to release light photons of energy 24/05/2015Hardware Fundamentals37

38. CRT versus LCD versus Plasma 24/05/2015Hardware Fundamentals38

39. 24/05/2015Hardware Fundamentals39 Calculated longer lifeHigher refresh rate Not affected by magnetic fieldsWider viewing angle No radiationMore contrast LighterBrighter colours Flat more compact screenMore robust Uses less powerCheaper LCDCRT

40. LCDPlasma CheaperMore expensive Positioned on deskHang on the wall Best image front-onWider viewing angle Smaller sizesLarger sizes Brighter display 24/05/2015Hardware Fundamentals40

41. Is CRT still the best for high- definition TV? 24/05/2015Hardware Fundamentals41

42. CRT monitor  Despite the popularity of LCD and Plasma screens, the best display of high-definition TV is still the CRT monitor 24/05/2015Hardware Fundamentals42

43. SED for the future 24/05/2015Hardware Fundamentals43

44. Surface-conduction Electron- emitter Display (SED)  Developers are Canon and Toshiba  Combines the best of CRT’s, LCD’s and plasma displays  Will have the visual quality of a CRT monitor and the slimness of LCD and plasma flat panels  Requires less materials than LCD and less expensive circuitry than plasma  Screen is made up of phosphors (CRT) painted on the inside of a plate of glass, each phosphor dot has its own emitter which shoots electrons at only its matching phosphor (no electron beam) 24/05/2015Hardware Fundamentals44

45. References  Required textbook  http://www.howstuffworks.com  http://www.webopedia.com  http://www.fourmilab.ch/documents/howmanydots/ 24/05/2015Hardware Fundamentals45