display modules

8/8/2019 Display Modules

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Perundurai-638052, Erode.

Paper presentation onDisplay Modules

Submitted by: NAME : R.Yazhini (08ITR069),

G.UmaMaheswari (08ITR082)YEAR : III YEAR DEPARTMENT : B.TECH (IT)COLLEGE : Kongu Engineering College,

Perundurai, Erode-638052.MOBILE : 94864 41417

E-mail: [email protected] ,[email protected]
mailto:[email protected]:[email protected]


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ABSTRACT:

A display device is an output device for presentation of information for visual, tactile or

auditive reception, acquired, stored, or transmitted in various forms. When the input

information is supplied as an electrical signal, the display is called electronic display .

Electronic displays are available for presentation of visual, tactile and auditive

information.

Common applications for electronic visual displays are television sets or computer

monitors.

The major element6s of display subsystem are,

Display device

Display adapter

Display subsystem software

In olden days, CRT monitors are in use. They are larger in size and weight and not

portable. Then the CRT displays are replaced by flat screen displays. These flat screen

displays are portable and consumes very less power when compared to CRT displays. Theflat screen displays include LCD, TFT, and plasma displays.

Many of latest displays are yet to come with more portable and less power consumption.

In this paper the present display modules and display modules on research are presented.


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CONTENTS:

Introduction

Display parameters

Types of flat panel displays

Volatile

Static

Most popular displays

CRT

LCD

Plasma Display

Latest Display Modules

TMOS display

OLED display

SED display

FED display

FLD display

iMOD display

Nanocrystal display

Conclusion


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INTRODUCTION:A monitor or display(sometimes called a visualdisplay unit ) is a piece of electrical equipment which

displays images generated by devices such ascomputers, without

producing a permanentrecord. The monitor comprises the displaydevice, circuitry, and anenclosure. The displaydevice in modern monitorsis typically a thin filmtransistor liquid crystaldisplay (TFT-LCD), whileolder monitors use acathode ray tube (CRT).Flat panel displaysencompass a growingnumber of technologiesenabling video displaysthat are lighter and muchthinner than traditionaltelevision and videodisplays that use cathoderay tubes, and are usuallyless than 100 mm (4inches) thick. They can bedivided into two generalcategories; volatile and

static .In many applications,specifically modern

portable devices such aslaptops, cellular phones,and digital cameras,whatever disadvantagesexist are overcome by the

portability requirements.DISPLAYPARAMETERS:

Luminance is measured incandelas per square meter.

Viewable image size ismeasured diagonally. For CRTs, the viewable size istypically one inch (25 mm)smaller than the tube itself.

Aspect ratios is the ratio of the horizontal length to thevertical length.

Display resolution is thenumber of distinct pixelsin each dimension that can

be displayed. (It does notmean currently displayed.)Maximum resolution islimited by dot pitch.

Dot pitch is the distance between pixels of the samecolor in millimeters. Ingeneral, the smaller the dot

pitch, the sharper the picture will appear.

Refresh rate is the number of times in a second that adisplay is illuminated.Maximum refresh rate islimited by response time.

Response time is the timea pixel in a monitor takesto go from active (black) toinactive (white) and back to active (black) again,measured in milliseconds.

Contrast ratio is the ratioof the luminosity of the

brightest color (white) tothat of the darkest color (black) that the monitor iscapable of producing.

Power consumption ismeasured in watts.


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Viewing angle is themaximum angle at whichimages on the monitor can

be viewed, without

excessive degradation tothe images. It is measuredin degrees horizontally andvertically.


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TYPES OF FLATPANEL DISPLAYS:1. VOLATILE:Volatile displays require

pixels be periodically

refreshed to retain their state, even for a staticimage. This refreshtypically occurs manytimes a second.Examples of volatile flatpanel displays

Plasma displays

Liquid crystal displays(LCDs)

Organic light-emittingdiode displays (OLEDs)

Light-emitting diodedisplays (LED)

Surface-conductionelectron-emitter displays(SEDs)

Field emission displays(FEDs)

2. STATIC:Static flat panel displaysrely on materials whosecolor states are bistable.This means that the imagethey hold requires noenergy to maintain, butinstead requires energy tochange.Examples of static flatpanel displays

Interferometric modulator displays (e.g., Qualcomm'siMod display.)

Bistable nematic liquidcrystal displays (e.g.,ZBD)

MOST POPULAR

DISPLAYS:1. CATHODE RAYTUBE :The cathode ray tube(CRT) is a vacuum tubecontaining an electron gun(a source of electrons) anda fluorescent screen, withinternal or external meansto accelerate and deflectthe electron beam, used tocreate images in the formof light emitted from thefluorescent screen. Theimage may representelectrical waveforms(oscilloscope), pictures(television, computer monitor), radar targets andothers.Cutaway rendering of acolor CRT: 1. ThreeElectron guns (for red,green, and blue phosphor dots) 2. Electron beams 3.Focusing coils 4.Deflection coils 5. Anodeconnection 6. Mask for separating beams for red,green, and blue part of displayed image 7.Phosphor layer with red,green, and blue zones 8.Close-up of the phosphor-coated inner side of thescreenPros:

Very high dynamic range.Up to 15,000:1.


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Can display natively inalmost any resolution andrefresh rate.

Excellent viewing angle.

Cons:

Image contrast lower thanin LCDs

Large size and weight

Greater power consumption than similarlysized displays, such asLCD.

2. LIQUID CRYSTALDISPLAY:A liquid crystal display(LCD) is a thin, flat panelused for electronicallydisplaying informationsuch as text, images, andmoving pictures. Its usesinclude monitors for computers, televisions,instrument panels, andother devices ranging fromaircraft cockpit displays, toevery-day consumer devices such as video

players, gaming devices,clocks, watches,calculators, andtelephones. Among itsmajor features are itslightweight construction,its portability, and itsability to be produced inmuch larger screen sizesthan are practical for theconstruction of cathode raytube (CRT) displaytechnology. Its lowelectrical power

consumption enables it to be used in battery-poweredelectronic equipment.Pros:

Higher imagecontrast(static) inmodernLCDs.

Verycompactand light.

Low power consumption.

Little or noflicker dependingon back light.

Cons:

Manycheaper LCDs havelimitedviewingangle

Dead pixelsare possibleduring

manufacturing.


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3. PLASMA DISPLAY:A plasma display panel(PDP) is a type of flat

panel display common tolarge TV displays (80 cmor larger). Many tiny cells

between just two panels of glass hold a mixture of noble gases. The gas in thecells is electrically turnedinto a plasma which emitsultraviolet light which thenexcites phosphors to emitvisible light. The xenon,

neon, and helium gas in a plasma television iscontained in hundreds of thousands of tiny cells

positioned between two plates of glass.Pros:

Compactand light.

Highcontrastratios(10,000:1 or greater).

High speedresponse.

Cons:

Highoperating

temperature.

High power consumption.

Dead pixelsare possibleduringmanufacturi

ng.

LATEST DISPLAYMODULES:1. TMOS DISPLAY:Time multiplexed opticalshutter (TMOS ) is a flat

panel display technologydeveloped, patented andcommercialized by Uni-

Pixel Displays, Inc. TMOSis based on the principlesof total internal reflection(TIR), frustration of TIR (FTIR) and field sequentialcolour generation (FSC).The combination of thesethree technologies makes


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TMOS a revolution withinthe world of screens for itsfeatures and its largenumber of applications:mobile phones, televisions

and signaling systems.

3.8 cm TMOS displayOPERATINGPRINCIPLE:

The illumination systememits periodically red,green and blue light, eachcolor cycles for an equal

period of time in a veryhigh frequency.

The colored light entersinside de guide light, themirrored edges cause a

continual TIR reflections producing a highlyuniform of light energywithin the light guide.

The light is trapped in thelight guide until a voltagedifferential is created

between the twoconductive layers of thecapacitor at any pixel area.

When it happens the twoconductive planes attracteach other via Coulombattraction.

The Opcuity active layer isthe only moving part of TMOS and it is pulled

down until it touches thelight guide. Then, thespecific pixel is activatedand the light escapedthrough it due to the

phenomenon frustrationof total internal reflection(FTIR).

When the voltagedifferential disappears, theactive layer returns to itsinitial position and thelight is trapped again in thelight guide.

When the two conductivelayers are in contact is saidthat the pixel is open or active (ON) , when thelayers are separated thenthe pixel is closed or inactive (OFF) . Theduration of the chargedetermines the amount of time the shutter is open or closed. To generate imagesdisplays, the previous

process is specific for each pixel.GENERAL FEATURES:

Brightness :1400 cd/m2 in a 12,1display with 176 viewingangle at 13,2 watts. Even,it can achieve values of 3.430 cd/m2 at 30 watts.

Night vision : Because the red led iscontrolled independently,there is no necessity to addany infrared filter toachieve night visioncompatibility.


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Resolution : TMOS can achieve mmdot pitch due to itsunicellular pixel structure.

Viewing angle : Without additional steeringoptics angles as narrow as25x12 (12,5 left, 12,5right, 6 up, 6 down) can

be achieved.

Grey levels : 24 bits or 36 bits for special inherent systems.

Dimming range : 34 dB

Video Capability : 60 frames/second

ADVANTAGES:TMOS technology offersmany advantages over other popular technologieslike LCD, plasma andOLED.

Simplicity

Energyefficiency

Low cost

Good

contrast and brightness

Variety of applications

DISADVANTAGES:

The main disadvantage isthe necessity of a veryhigh velocity , if it isinsufficient a rainboweffect could appear at

blink.TMOS FUTURE:TMOS technology is still

being developed, it isexpected that on 2010 thefirsts mobile devices withTMOS displays will belaunched.In the future, it aims toimprove efficiency andfeatures of that kind of screens. Some of theseimprovements are going to

be a new guide lightmaterial, polycarbonate or flexible polymer, and theenlargement of the ledsgamut. The followingfeatures are beinginvestigated for TMOSdisplays:

Flexibility , allowing radiusof curvature up to 20 timesthe displays thickness.This characteristic willenable the creation of

photo-realistic images, thedevelopment of hometheatres that surround theviewer like IMAX screens.

Readabilit y in bright sunlight so they could beused for road and highwaysigns, tradeshows...etc.

Transparency , displayscould have a transparentrear therefore, they could

be used as windows from


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the inside and as displaysfrom the outside.

2. OLED DISPLAY:An organic light emitting

diode (OLED), alsoorganic electroluminescent device(OELD), is a light-emittingdiode (LED) whoseemissiveelectroluminescent layer iscomposed of a film of organic compounds. Thislayer of organicsemiconductor material isformed between twoelectrodes, where at leastone of the electrodes istransparent.

Sony XEL-1, the world'sfirst OLED TV


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Such devices can be usedin television screens,computer monitors, small,

portable system screenssuch as cell phones and

PDAs, watches,advertising, informationand indicationWORKINGPRINCIPLE:OLED layers: 1. Cathode(), 2. Emissive Layer, 3.Emission of radiation, 4.Conductive Layer, 5.Anode (+)

A voltage is applied acrossthe OLED such that theanode is positive withrespect to the cathode.

This causes a current of electrons to flow throughthe device from cathode toanode.

Thus, the cathode giveselectrons to the emissivelayer and the anodewithdraws electrons fromthe conductive layer

Soon, the emissive layer becomes negativelycharged, while theconductive layer becomesrich in positively chargedholes.

Electrostatic forces bringthe electrons and the holestowards each other andthey recombine. Thishappens closer to theemissive layer, because inorganic semiconductorsholes are more mobile than

electrons. Therecombination causes adrop in the energy levels of electrons, accompanied byan emission of radiation

whose frequency is in thevisible region. That is whythis layer is calledemissive.

Indium tin oxide iscommonly used as theanode material.

3. SED DISPLAY:

A surface-conductionelectron-emitter display(SED) is a flat panel color television technologycurrently being developed

by a number of companies . SEDs use nanoscopic- scale electron emitters toenergize colored

phosphors and producean image. SEDs areclosely related to another developing displaytechnology, the FED.

4. FIELD EMISSIONDISPLAY:

A field emission display(FED) is a flat paneldisplay technology thatuses large-area field electron sources to

provide electrons that strike colored phosphor to produce a color image . Ina general sense, a FEDconsists of a matrix of cathode ray tubes, each


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tube producing a singlesub-pixel, grouped inthrees to form red-green-

blue (RGB) pixels.

5. FERRO LIQUIDDISPLAY:

Ferro Liquid Display or Ferro-electric LiquidDisplay (FLD) or FerroFluid Display (FFD) is

based on Ferro electric properties of certainliquids . Not all such fluidsare crystal but they aregenerically referred to asFerro Liquid CrystalDisplay (FLCD) also.These fluids have bistable

properties that can beswitched with a magneticfield.

6.INTERFEROMETRICMODULATOR DISPLAY:

The InterferometricModulator (iMoD) is anelectrically switched light modulator comprising amicro-machined cavity thatis switched on and off using driver ICs similar tothose used to addressLCDs. An iMoD basedreflective flat panel displaycan comprise hundreds of thousands of individuallyadressable iMoD elements

7. NANOCRYSTALDISPLAY:

Nanocrystal displays are anew type of experimentaldisplay that uses roboticmuscles to control small

prisms that have white

light shining throughthem. As the white light issplit by the prisms, color will be generated on ascreen. A specificfrequency of light can beobtained by rotating the

prism to the correspondingangle with respect to theincident light beam.

CONCLUSION:Thus number of displaystandards have beendeveloped in terms of resolution, color, displayadapters, screen sizes, etc.The future displays aremanufactured withconcentration of mainthree factors. They aresize, resolution and power consumption. HenceTMOS displays are goingto play a major role inmany applications.

display modules

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