Display hardware vector displays 1963 modified oscilloscope 1974 Evans and Sutherland Picture System raster displays 1975 Evans and Sutherland frame buffer 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 Main applications Oscilloscope TV Old monitors Cathode Ray Tube 1 2 1
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 beam Light Deflection system 3 Small deflections Used in Osciloscopes 4 2
Magnetic Deflection Deflection Signals H d t V d t Greater deflections Used in TVs 5 6 3
Vector Displays or random scan display Vector Displays 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
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
Raster Scan Frame / Line Rate T H = Horizontal Scanning Period T V = Vertical Scanning Period H sinc L H H d Frame Rate: Line Rate: 1 FR T V LR 1 FR NL T H Frames / sec. Quadros / seg. Hz Lines / sec. Linhas / seg. Hz H d T H t V sinc V V d Nº de linhas de um quadro: T NL T V H 1 FR T H Nº de linhas visíveis: V d NL NL' T V t 11 12 6
Color CRT Shadow Masks 13 14 7
Monitor Example 40VM9H Screen Size Resolution Scanning Frequency Video Input Video Output Power Source Power Consumption Environmental Operating Temperature Operating Humidity Mechanical Dimensions (H x W x D) Weight Safety Standards 9 B&W Monitor 8.74 Diagonal >1000 TVL Horizontal 15,750Hz / Vertical 60Hz (EIA) Horizontal 15,625Hz / Vertical 50Hz (CCIR) Composite 1Vp-p 75 Ohm loop through BNC via impedance switch Composite 1Vp-p CVBS 75 ohms 90V ~ 120VAC (60/50Hz) <25W (EIA/CCIR) 10 C ~ +40 C (14 F ~ 105 F) 30% ~ 80% (no condensation) 222.25mm x 215.9mm x 254mm (8.75 x 85 x 10 ) 6.8 kg (15 lbs) UL, LVD, CE, RoHS 15 16 8
Monitor example Monitor Example 5 CRT Monitor 01 Professional Large LCD Monitor SPECIFICATION Model SMT-3222 SMT4022 Standard: CCIR 625 Line 50Hz and RS 170 60Hz interlaced. Aspect ratio: Switchable between 4:3 and 4:1.77 Video impedance: 75 ohms ±2%. General Screen Size 32" 40" Resolution (HxV) 1366 x 768 1920 x 1080 Pixel Pitch (mm) 0.511 x 0.511 (HxV) 0.46125 x 0.46125 (HxV) Brightness(cd/m2) 450 Input type: Differential Grey levels: 16 at 100 cd/m2 Video bandwidth: >12MHz -3dB Gain control: Contrast control on front panel Contrast Ratio 4,000:1 (Dynamic Contrast Ratio 40,000:1) Response Time (ms) 8 (G-to-G) Viewing Angle (H/V) 178 / 178 Panel Lamp Life 50,000HR Display Colors 16.7M Horizontal Frequency Vertical Frequency 30 ~ 81KHz 56 ~ 85Hz Black level control: Brightness control on front panel Warm up time: 15 seconds after power Power requirements: 28V to MIL-STD-1275B Power consumption total: <20 watts (at 450cd/m2) June 2006 17 Horizontal Resolution Comb Filter Sync Format Feature 600TV Lines 3D Screen Aspect Ratio 4:3 / 16:9 Language NTSC : 3.5 / PAL : 4.43 / Secam English / French / German / Italian / Portuguese / Russian / Spanish / Swedish / Chinese / Japanese / Korean / Turkish / Taiwanese 18 9
Raster CRT Raster CRT pros: Allows solids, not just wire frames Low-cost technology (i.e., TVs) Bright! Display emits light Cons: Requires screen-size memory array Discrete sampling (pixels) Practical limit on size 1 Graphics Card RD A 15 A 8 RAM DAC DAC DAC DotCLK Counter Counter Osc D 0 D 3 D 4 D 7 D 8 D 11 A 7 -A 0 R G B Hsinc Vsinc 19 20 10
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
Color Table Page RAM 8192 x 1024 x 8 x 13 x 13 Address A0 - A12 Nr of simulataneous colors = 2 bits/pixel Exemple: 8 bits/pixel => 2 8 = 256 visible colores 23 x 10 x 10 24 12
VRAM IBM 4MB 3D-RAM 25 26 13
Graphic Computer Dual Buffer + Z 27 28 14
RGB CMY Models B G R Used in electrostatic and ink-jet plotters that deposit pigment on paper Cyan, magenta, and yellow are complements of red, green, and blue, respectively C 1 R White (0, 0, 0), black (1, 1, 1) CMYK Model: K (black) is used as a primary color to save ink deposited on paper => dry quicker M 1 G Y 1 B Green Yellow (minus blue) - popularly used by printing press (minus red) Cyan Black Red Blue Magenta (minus green) 29 30 15
YUV Y luma, brightness, luminance 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. Y UV Y gamma corrected Y Variations: Y UV, YCbCr, YPbPr 31 32 16
HSL Interactive Specification of Color HSL - Hue, Saturation, Lightness H Hue: Cor percebida por humanos S Saturation: 100%=cor pura 0%=level of gray vermelho L branco Many application programs allow the user to specify colors of areas, lines, text, and so on. Interactive selection: L Lightness: 100%=white 0%=black S H verde azul preto Perception of color is affected by surrounding colors and the sizes of colored areas 33 34 17
Analogue Television Interlaced lines 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
Composite Video Composite Video Monitor Video Source H sync L Video encoder Composite video Video decoder H sinc L H H d V sync V sinc V V d http://en.wikipedia.org/wiki/composite_video 37 38 19
Composite Video Color TV http://en.wikipedia.org/wiki/pal 39 40 20
Composite Video CVBS Source Monitor Color, Video, Blanking, Sync H sync V sync Video encoder Composite video Video decoder H sync V sync R G B RGB to YUV Y U V Y U V YUV to RGB R G B 41 42 21
PAL PAL http://en.wikipedia.org/wiki/dvb-t 43 44 22
SECAM - Sequential Couleur Avec Memoire HSync On Green 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
Sync On Green Resolutions 47 http://en.wikipedia.org/wiki/display_resolution 48 24
Flat Panel Displays Volatile Pixels are periodically refreshed to retain their state Refresh many times a second Otherwise image will fade from the screen Plasma, LCD, OLED, LED, ELD, SED and FED-displays Liquid Crystal Displays (LCDs) LCDs: organic molecules, naturally in crystalline state, that liquefy when excited by heat or E field Crystalline state twists polarized light 90º. 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
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
Passive Matrix LCD Problems Pixel is ON only during scan access. More Rows => shorter on-voltage time Reduced bright, poor contrast ratio, narrow viewing angle, fewer gray levels. Thin Film Transistor TFT (Thin film transistor): a special kind of FET Basic FET Higher voltages => more crosstalk between neighbor pixels Scan frequency is limited by LC response delay. Flicker MISFET Solution placing an active element at each pixel switch and memory transistor and capacitor 53 http://www.wikipedia.org TFT 54 27
TFT Active Matrix TFT Active Matrix 55 56 28
Display Technology: LCDs LCDs act as light valves, not light emitters, and thus rely on an external light source. Transmissive & reflective LCDs: Laptop screen: backlit, transmissive display Palm Pilot/Game Boy: reflective display CCFL Backlight Cold-Cathode Fluorescent Lamp Driving Voltage: 100 ~ 400Vac, 30 ~ 50KHz (DC/AC Inverter required) Brightness (Min): 1 000 cd/m 2 (direct application) 450 cd/m 2 (side application) Luminous Color: White Life Time: 15 000 ~ 20 000 Hrs Operating Temperature: 0 ~ +60 c Storage Temperature: -20 ~ +70 c 57 58 29
CCFL Backlight Backlight Structure CCFL Backlight Cold-Cathode Fluorescent Lamp Direct Advantages Simple Design Good for Color LCD Good Uniformity High Brightness Disadvantages Narrow Drive Temperature High Frequency & AC Signal Operation Needs DC/AC inverter Side Lightguide Long Life Low Heat Generation 59 60 30
LED Backlight Driving Voltages: 2.1V ~ 8Vdc Brightness (Min): 70 cd/m 2 5 ~ 30 cd/m 2 Luminous Color: Yellow-Green, White, Green, Blue, Amber, Red Life Time: 100 000 Hrs Operating Temperature: -20 ~ +70 C Storage Temperature: -20 ~ +85 C LED Backlight LED Backlight structure Direct Side Lightguide 61 62 31
LED Backlight Plasma Panel Advantages Very Long Life Wide Temperature DC Single Operation Various Colors Disadvantages Low Uniformity Less brightness than CCFL Price Similar in principle to fluorescent light tubes. Each element is a small gas-filled capsule. When excited by electric field, emits UV light. UV excites phosphor. Phosphor relaxes, emits some other color. Lower thickness Low Power Comsumption 63 64 32
Plasma Panel Plasma Panel Plasma Display Panel Pros Large viewing angle Good for large-format displays Fairly bright Cons Expensive Large pixels (~1 mm versus ~0.2 mm) Phosphors gradually deplete Less bright than CRTs, using more power 65 66 33
Field Emission Display FED Developed by Motorola and others during the 1990s Very similar to a CRT matrix Utilizes an electron emitter which activates phosphors on a screen In CRT an electron gun scatters the charged particles Each FED pixel has its own corresponding electron source At first conical electron emitters (known as a "Spindt tip") nowdays carbon nanotubes Electrons in a FED are not produced by heat 67 68 34
FED FED Advantages More power efficient than LCD Less weight that same size LCD Fewer total components and processes involved Disadvantages Erosion of the emitters Extremely high vacuum required in order to operate Hard to manufacture for commercial use Production difficulties First models 2007 19.2-inches. 1 280 x 960 resolution brightness of 400cd/m 2 20 000:1 contrast ratio Sony s Field Emission Technologies, whose purpose was to develop the displays closed it doors in 2009. Reason mainly due to difficulty in raising funds for manufacturing. 69 70 35
Surface-conduction Electron-emitter Display SED Co-developed by Canon and Toshiba Corporation Very similar to a CRT matrix Utilizes an electron emitter which activates phosphors on a screen The electron emission element is made from few nanometers thick electron emission film No electron beam deflector required Separate emitter for each color phosphor, 3/pixel or 1/sub-pixel Source: http://www.oled-display.info/what-means-sed-tv 71 72 36
SED SED Advantages The overall power efficiency about ten times better than a LCD of the same size. Less complex than LCD. Fast response time and high contrast ratio. Wide viewing angle advantages over the FED in manufacturing state. Prototype 2006 1080p 55-inch models 450 nits of brightness 50 000:1 contrast ratio 1ms response time Disadvantages Potential screen burn-in. Mass production difficulties. 73 Mass production delayed due to lawsuits between Canon and Nano-Proprietary Inc concerning SED panel patent license agreement. In 2010 Canon announced project shut down. 74 37
Organic Light-emitting Diode Developed by Eastman-Kodak Two types: small molecule OLED and polymer OLED A Layer of organic material is sandwiched between two conductors (an anode and a cathode) which are between seal and subsrate Electro-luminescent bright light is produced from the organic material when current is applied to the conductors OLED color Only pure colors expressed when an electric current stimulates the relevant pixels Primary color matrix arranged in red, green, and blue pixels, mounted directly to a printed circuit board Ambient light interference reduced with "micro-cavity structure -> improves overall color contrast Organic layer adjusted for each color for strongest light Colors purified with color filter without the need for polarizer -> outstanding color purity. 75 76 38
OLED How OLED is built OLED production VS. LCD production 77 78 39
PLED Different OLED technologies AM OLED = Active Matrix OLED device FOLED = Flexible Organic Light Emitting Diode (UDC) OLED = Organic Light Emitting Diode/Device/Display PhOLED = Phosphorescent Oragnic Light Emitting Diode (UDC) PLED = Polymer Light Emitting Diode (CDT) PM OLED = Passive Matrix OLED device POLED = Polymer Oragnic Light Emitting Diode (CDT) RCOLED = Resonant Coloe Oragnic Light Emitting Diode SmOLED = Small Molecule Ogranic Light Emitting Diode (Kodak) SOLED = Stacked Oragnic Light Emitting Diode (UDC) TOLED = Transparent Oragnic Light Emitting Diode (UDC) Source: http://www.educypedia.be/electronics/pled.htm 79 80 40
OLED Advantages Can be printed onto any suitable substrate with inkjet (PLED) Flexible displays Great artificial contrast ratio and color potential No need for a backlight Great viewing angle Fast response times Disadvantages Lifespan (especially blue) Color balance issues (due to lifespan issues) Water damage Outdoor performance Power consumption Possible screen burn-in 81 OLED Samsung SDI exhibited a 40-inch OLED panel at the FPD International 2008 full HD resolution of 1920 x 1080 contrast ratio of 1,000,000:1 color gamut of 107% NTSC luminance of 200cd/m2 (peak luminance of 600cd/m2) At CES-2010 (Consumer Electronics Show): Samsung showed several OLED 3D Panels. Sony showed 24.5-inch prototype OLED 3D television. 82 41
OLED 3LCD Projectors Source: DisplaySearch Q2,09 Quarterly OLED Shipment and Forecast Report 83 84 42
DMD DMD: Digital Micromirror Devices Microelectromechanical (MEM) devices fabricated with VLSI techniques DLP - Digital Light Processing DMD implementation by Texas Instruments. Used in projectors and also back-projected displays. The image is created by a matrix of microscopic moving mirrors mounted in an integrated circuit (DMD). Each mirror creates one pixel in the projected image. http://www.dlp.com DMD Digital Mirror Device 85 86 43
Future Some of the technologies have faded after the prototype phase Projection W OLEDs are the most promising Flexible displays Printing technology Printed vs non printed Rigid vs flexible Inorganic vs organic, Cost of materials vs process New technologies still in development W=2 d tan( x /2) H=2 d tan( y /2) x d 87 88 44
Throw ratio Projector Example Throw = distance from projector to screen (d) Throw ratio (TR): 89 90 45