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    Computer graphics report Computer graphics report Document Transcript

    • Computer GraphicsTopic: - Flat - Panel displaysSubmitted to: Submitted by:As. Prof Aman Deep Kaur Alisha Korpal Nivia Jain Sharuti Jain 1|Page
    • IndexS no Topic Page no 1 Introduction 2 CRT 3 Advantages & disadvantages 4 Flat panel 5 Types 6 Emissive 7 LCD 8 Plasma Panel 2|Page
    • IntroductionVideo display devicesA display device is an output device for presentation of information in visual or tactileform (the later used for example in tactile electronic displays for blind people). When theinput information is supplied as an electrical signal, the display is called an electronicdisplay.How the interactive Graphics display worksThe modern graphics display is extremely simple in construction.Three components:  A digital memory or frame buffer in which the displayed image is stored as a matrix of intensity values  A monitor  Display controller, which is a simple interface that passes he content of frame buffer to the monitor. Inside the frame buffer the image is stored as pattern of binary digital numbers, which represents a rectangular array of picture elements or pixel. 3|Page
    • Types of video display devices:  Cathode Ray Tube  Flat - Panel Display 4|Page
    • Cathode Ray TubeThe cathode ray tube (CRT) is a vacuum tube containing an electron gun (a source ofelectrons) and a fluorescent screen, with internal or external means to accelerate anddeflect the electron beam, used to create images in the form of light emitted from thefluorescent screen. The image may represent electrical waveforms (oscilloscope),pictures (television, computer monitor), radar targets and others.The CRT uses an evacuated glass envelope which is large, deep, heavy, and relativelyfragile.Cathode rays (also called an electron beam or e-beam) are streamsof electrons observed in vacuum tubes. If an evacuated glass tube is equipped withtwo electrodes and a voltage is applied, the glass opposite of the negative electrode isobserved to glow, due to electrons emitted from and travelling perpendicular tothe cathode (the electrode connected to the negative terminal of the voltage supply).They were first observed in 1869 by German physicist Johann Hittorf, and were namedin 1876 by Eugen Goldstein kathodenstrahlen, or cathode rays.Electrons were first discovered as the constituents of cathode rays. In 1897 Britishphysicist J. J. Thomson showed the rays were composed of a previously unknownnegatively charged particle, which was later named the electron. Cathode raytubes (CRTs) using a focused beam of electrons deflected by electric or magnetic fields,create the image in a classic television set. 5|Page
    • Advantages and DisadvantagesAdvantages → High dynamic range (up to around 15,000:1), excellent color, wide gamut and low black level. The color range of CRTs is unmatched by any display type except OLED. → Can display in almost any resolution and refresh rate → No input lag → Sub-millisecond response times → Near zero color, saturation, contrast or brightness distortion. Excellent viewing angle. → Allows the use of light guns/pensDisadvantages → Large size and weight, especially for bigger screens (a 20-inch (51 cm) unit weighs about 50 lb (23 kg)) → High power consumption → Generates a considerable amount of heat when running → Geometric distortion caused by variable beam travel distances → Can suffer screen burn-in → Produces noticeable flicker at low refresh rates → Color displays (at PAL or NTSC resolution) cannot be made in sizes smaller than 7 inches without incurring quasi-exponential cost increases per centimeter decrease in size. → The maximum practical size for CRTs is around 24 inches for computer monitors; most direct view CRT televisions are 36 inches or smaller, with regular- production models limited to about 40 inches. 6|Page
    • Flat Panel DisplaysFlat panel displays (sometimes called Flat screen, however, strictly Flat screen is alsoused to describe CRT screens that have a completely flat front surface) encompass agrowing number of electronic visual display technologies enabling much lighter andthinner than traditional television set and video displays that use cathode raytubes (CRT), and are usually less than 100 mm (4 inches) thick. They can be dividedinto two general display technology categories; volatile and static.The first ever flat panel display was invented in 1964 at the University of Illinois.In many applications, specifically modern portable devices such as laptops, cellularphones, and digital cameras, camcorders, compact cameras, Pocket video camera,whatever disadvantages exist are made up for by the portability requirements.A very thin display screen used in portable computers. Nearly all modern flat-paneldisplays use LCD technologies. Most LCD screens are backlit to make them easier toread in bright environments. 7|Page
    • Types of Flat panel Displays  Emissive display devices o Plasma panels o Electroluminescent displays  Non emissive display devices o LCD 8|Page
    • Emissive display devicesA emission display (FED) is a display technology that incorporates flat paneldisplay technology that uses large-area field electron emission sources to provideelectrons that strike colored phosphor to produce a color image as a electronic visualdisplay. In a general sense, a FED consists of a matrix of cathode ray tubes, each tubeproducing a single sub-pixel, grouped in threes to form red-green-blue (RGB) pixels.FEDs combine the advantages of CRTs, namely their high contrast levels and very fastresponse times, with the packaging advantages of LCD and other flat paneltechnologies. They also offer the possibility of requiring less power, about half that of anLCD system.After considerable time and effort in the early and mid-2000s, Sonys FED efforts startedwinding down in 2009 as LCD became the dominant technology. In January 2010, AUOptronics announced that it acquired essential FED assets from Sony and intends tocontinue development of the technology.FEDs are closely related to another developing display technology, the surface-conduction electron-emitter display, or SED, differing primarily in details of the electronemission system. In August 2010, Canon announced they were shutting down their jointeffort to develop SEDs commercially, signaling the end of development efforts. 9|Page
    • LCDA liquid crystal display (LCD) is a flat panel display, electronic visual display, videodisplay that uses the light modulating properties of liquid crystals (LCs). LCs do not emitlight directly.They are used in a wide range of applications, including computer monitors, television,instrument panels, aircraft cockpit displays, signage, etc. They are common inconsumer devices such as video players, gaming devices, clocks, watches, calculators,and telephones. LCDs have displaced cathode ray tube (CRT) displays in mostapplications. They are usually more compact, lightweight, portable, less expensive,more reliable, and easier on the eyes. They are available in a wider range of screensizes than CRT and plasma displays, and since they do not use phosphors, they cannotsuffer image burn-in.LCDs are more energy efficient and offer safer disposal than CRTs. Its low electricalpower consumption enables it to be used in battery-powered electronic equipment. It isan electronically modulated optical device made up of any number of segments filledwith liquid crystals and arrayed in front of a light source (backlight) or reflector toproduce images in color or monochrome. The most flexible ones use an array ofsmall pixels. The earliest discovery leading to the development of LCD technology, thediscovery of liquid crystals, dates from 1888. By 2008, worldwide sales of televisionswith LCD screens had surpassed the sale of CRT units. 10 | P a g e
    • Plasma displayA plasma display panel (PDP) is a type of flat panel display common to large TVdisplays 30 inches (76 cm) or larger. They are called "plasma" displays because thetechnology utilizes small cells containing electrically charged ionized gases, or what arein essence chambers more commonly known as fluorescent lamps.Plasma displays are bright. They have a very low-luminance "dark-room" black levelcompared to the lighter grey of the un illuminated parts of an LCD screen (i.e. the blacksare blacker on plasmas and greyer on LCDs). LED-backlit LCD televisions have beendeveloped to reduce this distinction. The display panel itself is about 6 cm (2.5 inches)thick, generally allowing the devices total thickness (including electronics) to be lessthan 10 cm (4 inches). Plasma displays use as much power per square meter asa CRT or an AMLCD television. Power consumption varies greatly with picture content,with bright scenes drawing significantly more power than darker ones – this is also trueof CRTs. Typical power consumption is 400 watts for a 50-inch (127 cm) screen. 200 to310 watts for a 50-inch (127 cm) display when set to cinema mode. Most screens areset to shop mode by default, which draws at least twice the power (around 500–700watts) of a home setting of less extreme brightness. Panasonic has greatly reducedpower consumption ("1/3 of 2007 models") Panasonic states that PDPs will consumeonly half the power of their previous series of plasma sets to achieve the same overallbrightness for a given display size. The lifetime of the latest generation of plasmadisplays is estimated at 100,000 hours of actual display time, or 27 years at 10 hoursper day. This is the estimated time over which maximum picture brightness degrades tohalf the original value. 11 | P a g e
    • Plasma display screens are made from glass, which reflects more light than the materialused to make an LCD screen. This causes glare from reflected objects in the viewingarea. Companies such as Panasonic coat their newer plasma screens with an anti-glarefilter material. Currently, plasma panels cannot be economically manufactured in screensizes smaller than 32 inches. Although a few companies have been able to makeplasma Enhanced-definition televisions (EDTV) this small, even fewer have made 32inplasma HDTVs. With the trend toward large-screen television technology, the 32inscreen size is rapidly disappearing. Though considered bulky and thick compared totheir LCD counterparts, some sets such as Panasonics Z1 and Samsungs B860 seriesare as slim as one inch thick making them comparable to LCDs in this respect.Competing display technologies include Cathode ray tube (CRT), Organic light-emittingdiode (OLED), AMLCD, Digital Light Processing DLP, SED-tv, LED display, fieldemission display(FED), and Quantum dot display (QLED). 12 | P a g e
    • Advantages  Picture quality  Capable of producing deeper blacks allowing for superior contrast ratio  Wider viewing angles than those of LCD; images do not suffer from degradation at high angles like LCDs  Less visible motion blur, thanks in large part to very high refresh rates and a faster response time, contributing to superior performance when displaying content with significant amounts of rapid motion  Slim profile  Can be wall mounted  Less bulky than rear-projection televisions 13 | P a g e
    • Disadvantages  Earlier generation displays were more susceptible to screen burn-in and image retention, although most recent models have a pixel orbiter that moves the entire picture faster than is noticeable to the human eye, which reduces the effect of burn-in but does not prevent it.  Earlier generation displays (2006 and prior) had phosphors that lost luminosity over time, resulting in gradual decline of absolute image brightness (newer models are less susceptible to this, having life spans exceeding 100,000 hours, far longer than older CRT technology) Earlier generation (circa 2001 and earlier) models were susceptible to "large area flicker"  Heavier screen-door effect when compared to LCD or OLED based TVs  Generally do not come in smaller sizes than 37 inches  Heavier than LCD due to the requirement of a glass screen to hold the gases  Use more electricity, on average, than an LCD TV  Do not work as well at high altitudes due to pressure differential between the gases inside the screen and the air pressure at altitude. It may cause a buzzing noise. Manufacturers rate their screens to indicate the altitude parameters.  For those who wish to listen to AM radio, or are Amateur Radio operators (Hams) or Shortwave Listeners (SWL), the Radio Frequency Interference (RFI) from these devices can be irritating or disabling.  Due to the strong infrared emissions inherent with the technology, standard IR repeater systems can not be used in the viewing room. A more expensive "plasma compatible" sensor must be used. 14 | P a g e