Published on May 6, 2012
LCD , LED AND PLASMA TV: LCD , LED AND PLASMA TV INTRODUCTION: INTRODUCTION Television ( TV ) is a telecommunication medium for transmitting and receiving moving images that can be monochrome (Black and White) or colored, with or without accompanying sound. The word Tele is a Greek word meaning “Distant” and Vision meaning “Sight”. The components used in old TV's are essentially very similar to the components used in modern TV's; that is, they perform the same function as their modern counterparts. Where they differ greatly however, is in their size. PowerPoint Presentation: There are different types of TV depending upon the display device used. Display Device A display device is an output device for presentation of information in visual form. When the input information is supplied as an electrical signal, the display is called an electronic display . Types of Display Devices Cathode Ray Tube Flat - Panel Display Flow chart: Flow chart CATHODE RAY TUBE: CATHODE RAY TUBE The cathode ray tube (CRT) is a vacuum tube containing an electron gun ( a source of electrons) and a fluorescent screen, with internal or external means to accelerate and deflect the electron beam, used to create images in the form of light emitted from the fluorescent screen. FLAT PANEL DISPLAY: FLAT PANEL DISPLAY Flat panel displays (sometimes referred to as flatscreens , which more technically mean screens with fully flat front surfaces) encompass a growing number of electronic visual display technologies. They are far lighter and thinner than traditional television sets and video displays that use cathode ray tubes (CRTs), and are usually less than 10 centimetres (3.9 in) thick. Types of Flat panel Displays : Types of Flat panel Displays Emissive display devices Plasma panels Electroluminescent displays Non emissive display devices LCD LIQUID CRYSTAL DISPLAY(LCD): LIQUID CRYSTAL DISPLAY(LCD) Liquid-crystal display televisions ( LCD TV ) are color television sets that use LCD technology to produce images Produces colored image by selecting filtering a white light Thinner and lighter than CRTs of similar display size The concept of LCD was 1st brought up by Philips LIQUID CRYSTAL DISPLAY: LIQUID CRYSTAL DISPLAY Liquid Crystal – a stable phase of matter characterized by anisotropic properties without the existence of a 3-dimensional crystal lattice – generally lying between the solid and isotropic (“liquid”) phase . ISOTROPIC ANISOTROPIC (Liquid Crystals have orientational order) (Liquids and gases) PowerPoint Presentation: LIQUID CRYSTAL MODEL Unique Properties of Liquid Crystals: Unique Properties of Liquid Crystals The orientation of Liquid Crystals can be affected by… Pressure Temperature Electrical Field LCD Preparation: LCD Preparation Checking the ITO Glass Rubbing the PVA to create an alignment layer Removing the PVA at one edge Placing the Saran Wrap Spacers Applying the Liquid Crystal Placing the Polarizers at 90 ° Cross-sectional view: Cross-sectional view LCD Technology: LCD Technology Electrical-field NOT Applied Light IS transmitted Electrical-field IS Applied Light NOT transmitted LCD PIXEL: LCD PIXEL PowerPoint Presentation: PROPERTIES OF LCD DISPLAY Light weight (typ. 1/5 of CRT) power consumption (typ. 1/4 of CRT) No electromagnetic emission Large screens (>20 inch) on desktops Completely flat screen - no geometrical errors Crisp pictures - digital and uniform colors Fully digital signal processing possible Low luminance (typ. 200 cd /m2) PowerPoint Presentation: Led- Tvs An LED-backlit LCD display is a flat panel display that uses LED backlighting instead of the cold cathode (CCFL) backlighting used in other LCD displays. While not an LED display , televisions using this display are called " LED TV " by some manufacturers and suppliers. The use of LED backlighting allows for a thinner panel, lower power consumption, better heat dissipation, a brighter display, and better contrast levels Three forms of LED may be used: White edge-LEDs around the rim of the screen, using a special diffusion panel to spread the light evenly behind the screen (the most usual form) A full array of LEDs arranged behind the screen whose brightness are not controlled individually PowerPoint Presentation: Techniques used Edge-LEDs- Th is method of back-lighting allows LED-backlit displays to be extremely thin. The light is diffused uniformly across the screen by a special panel... Full-array LEDs- Many brands use LED backlighting technology, which can offer benefits over CCFL LCD TVs of reduced energy consumption, better contrast and brightness, greater colour range, more rapid response to changes in scene and more accurate image rendering. Dynamic 'Local Dimming' LEDs- This method of backlighting allows local dimming of specific areas of darkness on the screen. This can show truer blacks, whites and PRs [ at much higher dynamic contrast ratios by dimming or brightening the backlight locally, at the cost of less detail in small, bright objects on a dark background, such as star fields as well as shadow detail. PowerPoint Presentation: Difference between LCD and LED P roduce images with greater dynamic contrast ; W ith edge-LED lighting can be extremely slim, some screens less than half an inch (0.92 cm) thick. O ffer a wider color gamut when RGB-LED backlighting is used. P roduce less environmental pollution on disposal; A re more expensive; H ave typically 20 to 30% lower power consumption; A re more reliable. C an allow a wider dimming range. PLASMA TV : PLASMA TV Plasma display screens are made from glass, which reflects more light than the material used to make an LCD screen. A plasma display panel (PDP) is a type of flat panel display common to large TV displays 30 inches (76 cm) or larger. They are called " plasma " displays because the technology utilizes small cells containing electrically charged ionized gases Capable of producing deeper blacks allowing for superior contrast ratio PLASMA: PLASMA Plasma is a state of matter similar to gas in which a certain portion of the particles are ionized . Heating a gas may ionize its molecules or atoms (reduce or increase the number of electrons in them), thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions. In the universe , plasma is the most common state of matter . Some common plasmas are stars and neon signs . PLASMA LAMP PLASMA DISPLAY PANELS: PLASMA DISPLAY PANELS Cross-sectional view: Cross-sectional view FUTURE TECHNOLOGY OF TV: FUTURE TECHNOLOGY OF TV OLED (Organic light emitting diode) Sony introduced this technology in 2008 It doesn’t required backlighting Allow less power consumption Screen are so thin and so flexible that one can roll them up like a carpet We will have OLED based TV in our living room around 2015 SURFACE CONDUCTION ELECTRON (SED): SURFACE CONDUCTION ELECTRON (SED) Better quality picture. Power efficient. Long lasting Canon the originator of SED LASER TV: LASER TV The laser technology claims that the technology will allow displays with a richer, more vibrant colour palette than the conventional plasma, LCD or CRT displays They also claim the displays will: be half the weight and cost of plasma displays require around 25% of the power required by Plasma displays be very thin like plasma and LCD displays are today 3DTV: 3DTV It creates an ability to present viewer with two slightly different images One for the left eye and one for the right eye Auto-stereoscopic display is being used HALOGRAPHIC TV: HALOGRAPHIC TV Image project outward from TV as they appear to float in mid-air. One could walk around a specific object and look it from behind or can put himself in middle of the action . References :-: References :- en.wikipedia.org/wiki/ Plasma _(physics) www.howstuffworks.com › ... › Television › TV Technology en.wikipedia.org/wiki/ LED - backlit_LCD_display www. slideshare .net/Firedemon13/ plasma -8164874 - United States PowerPoint Presentation: THANK YOU!