display hardware cathode ray tube
play

Display hardware Cathode Ray Tube vector displays Main - PowerPoint PPT Presentation

Display hardware Cathode Ray Tube vector displays Main applications 1963 modified oscilloscope Oscilloscope 1974 Evans and Sutherland Picture System raster displays TV 1975 Evans and Sutherland frame


  1. Display hardware Cathode Ray Tube • vector displays • Main applications – 1963 – modified oscilloscope – Oscilloscope – 1974 – Evans and Sutherland Picture System • raster displays – TV – 1975 – Evans and Sutherland frame buffer – Old monitors – 1980s – cheap frame buffers  bit-mapped PCs – 1990s – liquid-crystal displays  laptops – 2000s – micro-mirror projectors  digital cinema – 2010s – high dynamic range displays? • other – stereo, head-mounted displays – autostereoscopic displays 1 2 1

  2. CRT Electrostatic Deflection • Electron Gun creates an electron beam with controllable intensity. • The deflection system moves the electron beam vertically and horizontally. • When the electron beam strikes the phosphor, it produces visible light on the fluorescent screen . • Only one point is lighted. Electron gun Light beam • Small deflections Deflection • Used in Osciloscopes system 3 4 2

  3. Deflection Signals Magnetic Deflection H d t V d t • Greater deflections • Used in TVs 5 6 3

  4. Vector Displays Vector Displays or random scan display – The electron beam is directed only to the parts of the screen where a picture is to be drawn. – Like plotters it draws a picture one line at a time – Used in line drawing and wireframe displays – Picture is stored as a set of line-drawing commands stored in a refresh display file. – Refresh rate depends on number of lines – Typicaly: • Refresh cycle is 30 to 60 times each second • 100 000 short lines at this refresh rate 7 8 4

  5. Vector Display Vector Displays Advantages  Generates higher resolution than other (Raster) systems  Produces smooth line drawings Disadvantage  Not usable for realistic shaded scenes 9 10 5

  6. Raster Scan Frame / Line Rate Frame Rate: T H = Horizontal Scanning Period 1 Frames / sec.  FR Quadros / seg. Hz T T V = Vertical Scanning Period V Line Rate: H d H sinc H  1 Lines / sec.    LR FR N L Linhas / seg. Hz T H L … H d V sinc V d Nº de linhas de um quadro: V T 1    V N L  T FR T T H t H H Nº de linhas visíveis: V d NL NL ' t T V 11 12 6

  7. Color CRT Shadow Masks 13 14 7

  8. Monitor Example 9” B&W Monitor 40VM9H Screen Size 8.74” Diagonal Resolution >1000 TVL Horizontal 15,750Hz / Vertical 60Hz (EIA) Scanning Frequency Horizontal 15,625Hz / Vertical 50Hz (CCIR) Composite 1Vp-p 75 Ohm loop through BNC via Video Input impedance switch Video Output Composite 1Vp-p CVBS 75 ohms Power Source 90V ~ 120VAC (60/50Hz) Power Consumption <25W (EIA/CCIR) Environmental Operating Temperature 10 ° C ~ +40 ° C (14 ° F ~ 105 ° F) Operating Humidity 30% ~ 80% (no condensation) Mechanical 222.25mm x 215.9mm x 254mm Dimensions (H x W x D) (8.75” x 85” x 10”) Weight 6.8 kg (15 lbs) Safety Standards UL, LVD, CE, RoHS 15 16 8

  9. Monitor example Monitor Example 5” CRT Monitor 01 Professional Large LCD Monitor SPECIFICATION Model SMT-3222 SMT4022 General Standard : CCIR 625 Line 50Hz and RS 170 60Hz interlaced. Screen Size 32" 40" Aspect ratio : Switchable between 4:3 and 4:1.77 Resolution (HxV) 1366 x 768 1920 x 1080 Pixel Pitch (mm) 0.511 x 0.511 (HxV) 0.46125 x 0.46125 (HxV) Video impedance : 75 ohms ± 2%. Brightness(cd/m2) 450 Contrast Ratio 4,000:1 (Dynamic Contrast Ratio 40,000:1) Input type : Differential Response Time (ms) 8 (G-to-G) Grey levels : 16 at 100 cd/m2 Viewing Angle (H/V) 178° / 178° Panel Lamp Life 50,000HR Video bandwidth : >12MHz -3dB Display Colors 16.7M Horizontal Frequency 30 ~ 81KHz Gain control : Contrast control on front panel Vertical Frequency 56 ~ 85Hz Horizontal Resolution 600TV Lines Black level control : Brightness control on front panel Comb Filter 3D Warm up time : 15 seconds after power Sync Format NTSC : 3.5 / PAL : 4.43 / Secam Feature Power requirements : 28V to MIL-STD-1275B Screen Aspect Ratio 4:3 / 16:9 English / French / German / Italian / Portuguese / Russian / Spanish / Power consumption total : <20 watts (at 450cd/m2) Language Swedish / Chinese / Japanese / Korean / Turkish / Taiwanese June 2006 17 18 9

  10. Graphics Card Raster CRT • Raster CRT pros: 1 D 0 RD R DAC D 3 RAM – Allows solids, not just wire frames D 4 G A DAC 15 D 7 A – Low-cost technology (i.e., TVs) 8 D 8 B DAC – Bright! Display emits light D 11 A -A 7 0 • Cons: – Requires screen-size memory array DotCLK Counter Counter Osc – Discrete sampling (pixels) Hsinc Vsinc – Practical limit on size 19 20 10

  11. Graphics Card Color Map DACs’ resolution Exemple: 4 bits => Nr. of colors = 2 (3*4) = 4096 visible colors Memory M = NC * NL * PS Exemple: 256 columns * 256 lines * 12 bits/pixel = 768 kbits = 96 kBytes DotCLK DotCLK = FR * NL’ * NC = LR * NC Exemple: 60 frames/second* 256 lines/frame * 256 pixels/line = 4 MHz 21 22 11

  12. Color Table Page RAM 8192 x 1024 x 8 x 13 x 13 Address A0 - A12 x 10 Nr of simulataneous colors = 2 bits/pixel x 10 Exemple: 8 bits/pixel => 2 8 = 256 visible colores 23 24 12

  13. VRAM IBM 4MB 3D-RAM 25 26 13

  14. Graphic Computer Dual Buffer + Z 27 28 14

  15. RGB CMY Models • Used in electrostatic and ink-jet plotters that deposit pigment on paper G • Cyan, magenta, and yellow are complements of red, green, and blue, respectively       C 1 R • White (0, 0, 0), black (1, 1, 1)         1 M G             R  Y   1   B  CMYK Model: K (black) is used as a primary color to save ink Green Yellow (minus blue) deposited on paper => dry quicker B - popularly used by printing press (minus red) Cyan Black Red Blue Magenta (minus green) 29 30 15

  16. YUV Y’UV Y – luma , brightness , luminance Y’ – gamma corrected Y U, V – chrominance Ideia : Y = R + G + B -> monochromatic image U = Y-B V = Y-R R = Y-V B = Y-U G = Y-R-B Advantages: • A monochromatic receptor can use only the Y channel • Resolution for U and V channels can be reduced …. Variations: Y’UV, YCbCr, YPbPr 31 32 16

  17. HSL Interactive Specification of Color • Many application programs allow the user to specify colors of areas, lines, HSL - Hue, Saturation, Lightness L text, and so on. branco H – Hue: Cor percebida por humanos • Interactive selection: S – Saturation: 100%=cor pura 0%=level of gray vermelho S L – Lightness: 100%=white 0%=black H azul verde preto • Perception of color is affected by surrounding colors and the sizes of colored areas 33 34 17

  18. Interlaced lines Analogue Television • How much bandwidth would we need for uncompressed digital television? • European TV format has 625 scan lines, 25 interlaced frames per second, 4:3 aspect ratio • It uses interlacing to reduce the vertical resolution to 312.5 lines • Horizontal resolution is 312.5*(4/3) = 417 columns • Bandwidth required 625*417*25 = 6.5MHz • Analogue colour information was quite cleverly added without increasing bandwidth (NTSC, PAL and SECAM standards) http://www.answers.com/topic/interlace?cat=technology http://en.wikipedia.org/wiki/PAL 35 36 18

  19. Composite Video Composite Video Monitor Video Video Video H sync H d H sinc encoder Composite decoder Source H video L L V sync V sinc V d V http://en.wikipedia.org/wiki/Composite_video 37 38 19

  20. Composite Video Color TV http://en.wikipedia.org/wiki/Pal 39 40 20

  21. CVBS Composite Video Color, Video, Blanking, Sync Source Monitor Video Video H sync H sync encoder Composite decoder video V sync V sync R Y Y R RGB YUV G U U G to to V B B V YUV RGB 41 42 21

  22. PAL PAL http://en.wikipedia.org/wiki/DVB-T 43 44 22

  23. HSync On Green SECAM - Sequential Couleur Avec Memoire • France, 1 October 1967 • developed in France (predominantly a political decision). • used in France and territories, C.I.S., much of Eastern Europe, the Middle East and northern Africa. • Line Frequency - 15.625 kHz • Scanning Lines – 625 (same as PAL) • Field Frequency - 50 Hz • Color Signal Modulation System FM Conversion System • Color Signal Frequency - 4.40625 MHz/4.250 MHz • Burst Signal Phase settled • Video bandwidth - B,G,H: 5.0 MHz; D,K,K1,L: 6.0 MHz • Sound Carrier - B,G,H: 5.5 MHz; D,K,K1,L: 6.5 MHz 45 46 23

  24. Sync On Green Resolutions http://en.wikipedia.org/wiki/Display_resolution 47 48 24

  25. Flat Panel Displays Liquid Crystal Displays (LCDs) Volatile • LCDs: organic molecules, naturally in crystalline • Pixels are periodically refreshed to retain their state state, that liquefy when excited by heat or E field • Refresh many times a second • Otherwise image will fade from the screen • Crystalline state twists polarized light 90º. • Plasma, LCD, OLED, LED, ELD, SED and FED-displays Static • Material with bistable color states • No energy needed to maintain image, only to change it. • Slow refresh state • Deployment in limited applications • Cholesteric displays, outdoor advertising, e-book products 49 50 25

  26. Liquid Crystal Displays (LCDs) Color Filters (RGB) Conventional color displays use a specific sub-pixel arrangement. • at high pixel densities, RGB or RGB Delta arrangement is adequate. • when the number of pixels is limited, the GRGB arrangement can be used. 51 52 26

Recommend


More recommend