Display hardware Ray Tube

• vector displays • Main applications – 1963 – modified oscilloscope – 1974 – Evans and Sutherland Picture System – Oscilloscope • 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 CRT Electrostatic Deflection

• 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 on the fluorescent screen. • Only one point is lighted.

Electron gun

Light beam

• Small deflections Deflection system • Used in Osciloscopes 3 4

2 Magnetic Deflection Deflection Signals

Hd

t

Vd

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. – 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

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5 Raster Scan Frame / Line Rate

Frame Rate:

1 Frames / sec. TH = Horizontal Scanning Period FR  Quadros / seg. Hz TV TV = Vertical Scanning Period Line Rate: H Hd sinc H 1 Lines / sec. LR   FR NL Linhas / seg. T Hz L H

H V V Nº de linhas de um quadro: d … sinc V d T 1 NL  V  TH t TH FR TH

Nº de linhas visíveis:

Vd NL NL'

t TV 11 12

6 Color CRT Shadow Masks

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7 Monitor Example

40VM9H 9” B&W Monitor

Screen Size 8.74” Diagonal Resolution >1000 TVL

Horizontal 15,750Hz / Vertical 60Hz (EIA) Scanning Horizontal 15,625Hz / Vertical 50Hz (CCIR)

Composite 1Vp-p 75 Ohm loop through BNC via Video Input impedance 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

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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. General 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 Black level control: Brightness control on front panel Horizontal Resolution 600TV Lines 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 Raster CRT Graphics Card

1 RD D0 R • Raster CRT pros: DAC D3 RAM

D4 G – Allows solids, not just frames A DAC 15 D A 7 – Low-cost technology (i.e., TVs) 8 D8 B DAC D11

– Bright! Display emits light A70 -A • Cons:

DotCLK – Requires screen-size memory array Counter Counter Osc

– Discrete sampling (pixels) Hsinc – Practical limit on size Vsinc

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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

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11 Color Table Page RAM

8192 x 1024 x 8 x 13 x 13

Address A0 - A12

x 10 bits/pixel Nr of simulataneous colors = 2 x 10 Exemple: 8 bits/pixel => 28 = 256 visible colores 23 24

12 VRAM IBM 4MB 3D-RAM

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13 Graphic Computer Dual Buffer + Z

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14 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)       M   1  G R  Y  1 B CMYK Model: K (black) is used       as a to save ink Green Yellow (minus blue) B deposited on paper => dry quicker

(minus red) - popularly used by printing press Cyan Black Red

Blue Magenta (minus green) 29 30

15 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 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 L – Lightness: 100%=white S 0%=black H

azul verde

preto • Perception of color is affected by surrounding colors and the sizes of colored areas

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17 Analogue 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 Video Video Hsync H Hd Source encoder Composite decoder sinc H L video L

Vsync V V sinc V d

http://en.wikipedia.org/wiki/Composite_video

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19 Composite Video Color TV

http://en.wikipedia.org/wiki/Pal

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20 Composite Video CVBS Color, Video, Blanking, Sync Source Monitor

Video Video Hsync Hsync encoder Composite decoder

Vsync video Vsync R Y Y R RGB YUV G U U G to to V B B YUV V RGB

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21 PAL PAL

http://en.wikipedia.org/wiki/DVB-T

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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

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23 Sync On Green Resolutions

http://en.wikipedia.org/wiki/Display_resolution 47 48

24 Flat Panel Displays Liquid Crystal Displays (LCDs) Volatile • Pixels are periodically refreshed to retain their state • LCDs: organic molecules, naturally in crystalline • Refresh many times a second state, that liquefy when excited by heat or E field • 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

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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.

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26 Passive Matrix LCD Problems

• Pixel is ON only during scan access. TFT (Thin film transistor): a special kind of FET

• More Rows => shorter on-voltage time • Reduced bright, • poor contrast ratio, Basic FET • narrow viewing angle, • fewer gray levels.

• Higher voltages => more crosstalk between neighbor pixels

• Scan frequency is limited by LC response delay. MISFET • Flicker

Solution • placing an active element at each pixel • switch and memory TFT • transistor and http://www.wikipedia.org 53 54

27 TFT TFT Active Matrix

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28 Display Technology: LCDs CCFL • LCDs act as light valves, not light emitters, and Cold-Cathode Fluorescent Lamp thus rely on an external light source. • Driving Voltage: 100 ~ 400Vac, 30 ~ 50KHz • Transmissive & reflective LCDs: – (DC/AC Inverter required) – Laptop screen: backlit, transmissive display • Brightness (Min): – Palm Pilot/Game Boy: reflective display – 1 000 cd/m2 (direct application) – 450 cd/m2 (side application) • Luminous Color: White • Life Time: 15 000 ~ 20 000 Hrs • Operating Temperature: 0 ° ~ +60° c • Storage Temperature: -20 ° ~ +70° c

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29 CCFL Backlight CCFL Backlight Backlight Structure Cold-Cathode Fluorescent Lamp

Direct Advantages Disadvantages Simple Design Narrow Drive Temperature

Good for Color LCD High Frequency & AC Signal Operation

Good Uniformity Needs DC/AC inverter

High Brightness

Long Life

Side Lightguide Low Heat Generation

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30 LED Backlight LED Backlight

LED Backlight structure • Driving Voltages: 2.1V ~ 8Vdc • Brightness (Min): 70 cd/m2 5 ~ 30 cd/m2 Direct • Luminous Color: Yellow-Green, White, Green, Blue, Amber, Red • Life Time: 100 000 Hrs • Operating Temperature: -20° ~ +70° C • Storage Temperature: -20° ~ +85° C Side Lightguide 61 62

31 LED Backlight Plasma Panel • Similar in principle to fluorescent light tubes. Advantages Disadvantages • Each element is a small gas-filled capsule. Very Long Life Low Uniformity • When excited by electric field, emits UV light. Wide Temperature Less brightness than CCFL • UV excites phosphor. DC Single Operation Price • Phosphor relaxes, emits some other color. Various Colors

Lower thickness

Low Power Comsumption

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32 Plasma Panel Plasma Panel

• 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

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33 Field Emission Display FED

• Developed by 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

• in a FED are not produced by heat

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34 FED FED

First models 2007 •19.2-inches. Advantages Disadvantages •1 280 x 960 resolution •brightness of 400cd/m2 • More power efficient than LCD • Erosion of the emitters •20 000:1 contrast ratio • Less weight that same size LCD • Extremely high vacuum • Fewer total components required in order to operate •’s Field Emission and processes involved • Hard to manufacture for Technologies, whose commercial use purpose was to develop the displays closed it • Production difficulties doors in 2009. •Reason mainly due to difficulty in raising funds for manufacturing.

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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. Prototype 2006 •Less complex than LCD. • 1080p 55-inch models •Fast response time and high contrast ratio. • 450 nits of brightness •Wide viewing angle advantages over the FED in manufacturing state. • 50 000:1 contrast ratio • 1ms response time

Disadvantages •Potential screen burn-in. •Mass production difficulties. 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. 73 74

37 Organic Light-emitting OLED color

• Developed by Eastman- • Only pure colors expressed when an electric current stimulates the relevant pixels • Two types: small molecule OLED and OLED • Primary color matrix arranged in red, green, and blue • A Layer of organic material is sandwiched between pixels, mounted directly to a two conductors (an and a cathode) which are between seal and subsrate • Ambient light interference reduced with "micro-cavity” structure -> improves overall color contrast • Electro-luminescent bright light is produced from the organic material when current is applied to the conductors • Organic layer adjusted for each color for strongest light

• Colors purified with color filter without the need for -> outstanding color purity.

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38 OLED How OLED is built

OLED production

VS.

LCD production

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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 OLED

Advantages • SDI exhibited a 40-inch OLED • Can be printed onto any suitable substrate with inkjet (PLED) panel at the FPD International 2008 • Flexible displays Great artificial contrast ratio and color potential • full HD resolution of 1920 x 1080 • No need for a backlight • contrast ratio of 1,000,000:1 • Great viewing angle • color of 107% NTSC • Fast response times • luminance of 200cd/m2 (peak luminance of 600cd/m2) Disadvantages • At CES-2010 (Consumer Electronics Show): • Lifespan (especially blue) • Samsung showed several OLED 3D • Color balance issues (due to lifespan issues) Panels. • Water damage • Sony showed 24.5-inch prototype • Outdoor performance OLED 3D television. • Power consumption • Possible screen burn-in 81 82

41 OLED 3LCD Projectors

Source: DisplaySearch Q2,09 Quarterly OLED Shipment and Forecast Report 83 84

42 DMD DLP -

DMD: Digital Micromirror Devices • DMD implementation by Texas Instruments. • Microelectromechanical (MEM) devices • Used in projectors and also back-projected displays. • fabricated with VLSI techniques • The image is created by a matrix of microscopic moving mirrors mounted in an (DMD). • Each mirror creates one pixel in the projected image.

http://www.dlp.com

DMD – Digital Mirror Device

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43 Future Projection • Some of the technologies have faded after the W prototype phase

• are the most promising • Flexible displays • Printing technology x d

• Printed vs non printed • Rigid vs flexible W=2  d  tan(x/2) • Inorganic vs organic, • Cost of materials vs process

• New technologies still in development H=2d tan(y/2)

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44 Throw ratio Projector Example

Throw = distance from projector to screen (d)

Throw ratio (TR):

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