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Touch screen technology-bharadwaj
 

Touch screen technology-bharadwaj

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    Touch screen technology-bharadwaj Touch screen technology-bharadwaj Presentation Transcript

    • TOUCH SCREEN TECHNOLOGY
    • Presented By SUBHAJIT BHARADWAJ 0301223250,8th sem Computer Sc.& Engg.
    • TALK FLOW
      • INTRODUCTION
      • HISTORY
      • FUNCTIONS
      • WORKING
      • DIFFRENT TOUCH SCREEN TECHNOLOGIES
      • APPLICATION
      • CONCLUSION
    • INTRODUCTION
      • A touch screen is a computer display screen that is sensitive to human touch , allowing a user to interact with the computer by touching pictures or words on the screen.
      • A touch screen is an input device that allows users to operate a PC by simply touching the display screen which has a sensitive glass overlay placed on it .
      • A touch screen accepts direct onscreen inputs.
    • HISTORY
      • In 1971, the first "touch sensor" was developed by Doctor Sam Hurst (founder of Elographics) while he was an instructor at the University of Kentucky.
      • The University of Kentucky Research Foundation named it as “Elograph”.
      • The "Elograph" was not transparent like modern touch screens.
      • In 1974, the first true touch screen incorporating a transparent surface came.
    • FUNCTIONS OF TOUCH SCREEN
      • Pressure sensitive activation-by finger or stylus.
      • Emulates mouse functions-click, double click, & drag.
      • Touch screen & mouse can be used concurrently.
      • Durable & scratch resistant coated surface.
      • Compatible with Windows 95,98,NT,2000,XP,Macintosh,Linux.
    • HOW DOES A TOUCHSCREEN WORKS?
      • A basic touch screen has three main components:
      • touch sensor
      • controller
      • software driver
    • 1.TOUCH SENSOR
      • A touch screen sensor is a clear glass panel with a touch responsive surface which is placed over a display screen.
      • The sensor generally has an electrical current or signal going through it and touching the screen causes a voltage or signal change. This voltage change is used to determine the location of the touch to the screen.
    •  
    • 2.CONTROLLER
      • The controller is a small PC card that connects between the touch sensor and the PC.
      • It takes information from the touch sensor and translates it into information that PC can understand.
    • 3.SOFTWARE DRIVER
      • The driver is a software that allows the touch screen and computer to work together.
      • It tells the operating system how to interpret the touch event information that is sent from the controller.
      • Most touch screen drivers today are mouse-emulation type drivers . This makes touching the screen the same as clicking your mouse at the same location on the screen.
    •  
    • DIFFERENT TOUCH SCREEN TECHNOLOGIES
      • RESISTIVE
      • CAPACITIVE
      • SURFACE WAVE
      • INFRARED
      • DISPERSIVE SIGNAL TECHNOLOGY
    • RESISTIVE TOUCH SCREEN TECHNOLOGY
      • Polyester Film .
      • Top Resistive Layer.
      • Conductive Transparent Metal Coating.
      • Bottom Resistive Layer .
      • Insulating Dots .
      • Glass Substrate
    •  
    • Contd.
      • Pressing the flexible top sheet creates electrical contact with the coating on the glass.
      • The touch screen controller gets the alternating voltages between the two layers and converts them into the digital X and Y coordinates of the activated area.
    • Advantages of Resistive Technology
      • Can be activated with any device
      • Low cost solution
      • Low power consumption
    • Disadvantages of Resistive Technology
      • Poorer durability compared to other technologies
      • Very short life, especially considering cosmetic wear
    • CAPACITIVE TOUCH SCREEN TECHNOLOGY
      • In the capacitive system , a layer that stores electrical charge is placed on the glass panel.
      • When a user touches, some of the charge is transferred to the user, so the charge on the capacitive layer decreases.
      • This decrease is measured in electrodes located at each corner of the monitor.
      • The computer then calculates the coordinates, from the relative differences in charge at each corner.
    • Contd.
      • A finger touch draws current from each corner.
      • Then the controller measures the ratio of the current flow from the corners and calculates the touch location
    • Capacitive Technology
      • ADVANTAGES
      •   More durable than resistive
      • Higher transmittance than resistive
      • DISADVANTAGES
      •      Accepts input from finger only.
      •                        
      •     Accuracy is dependent on capacitance of person
    • SURFACE WAVE TECHNOLOGY
      • It has a transmitting and receiving transducers for both the X and Y axes.
      • The touchscreen controller sends a five-megahertz electrical signal to the transmitting transducer, which converts the signal into ultrasonic waves within the glass.
      • These waves are directed across the front surface of the touchscreen by an array of reflectors.
    •  
    • Contd.
      • Reflectors on the opposite side gather and direct the waves to the receiving transducer, which reconverts them into an electrical signal.
      • When you touch the screen, you absorb a portion of the wave travelling across it.
      • The receivers can detect a drop in amplitude and thus coordinate is calculated.
      • ADVANTAGES
      •     Very high transmittance
      •    Very high durability  
      • DISADVANTAGES
      •   Requires “soft” input device
      • Surface obstructions can cause a false touch
    • INFRARED TOUCH SCREEN TECHNOLOGY
      • IR makes use of a “frame” around the perimeter of the display. On two sides there are closely spaced IR LEDs and on the opposing two sides there are matching photo transistors.
      • The LEDs are turned on in sequence and the signal is read from the matching transistor. If no signal is read, then that indicates a blocked IR beam, meaning a touch.
    •  
      • ADVANTAGES
      • Highest quality of underlying image
      • Very high transmittance  
      •    
      • Very high durability and reliability
      • DISADVANTAGES
      • Lower resolution than other technologies
      •     Surface obstructions can cause a false touch
    • DISPERSIVE SIGNAL TECHNOLOGY
      • This is the recent most technology, introduced in 2002.
      • It uses sensors to detect the mechanical ( vibrational )energy in the glass that occur due to a touch .
      • Complex algorithms then interpret this information and provide the actual location of the touch.
    • APPLICATIONS
      • Public Information Displays
      • tourism displays, trade show displays
      • Customer Self-Service stores, restaurants, transportation hubs, ATM and airline e-ticket terminals.
      • And many more uses... computerized gaming, student registration systems, multimedia software, financial and scientific applications, and more.
    • CONCLUSION
      • Touchscreens, touch panels or touchscreen panels are display overlays which have the ability to display and receive information on the same screen.
      • Touchscreens also have assisted in recent changes in the PDAs, making these devices more usable.
    •