Published on April 8, 2010

Author: balamadhu2007



TOUCH SCREEN TECHNOLOGY : TOUCH SCREEN TECHNOLOGY PRESENTED BY BALACHANDAR.K INTRODUCTION : INTRODUCTION Works with the principle of CRT (Cathode Ray Tube) technology. Input device --> Operates a PC by simply touching the display screen. Made of sensitive glass overlay & desired inputs can be given by touching it. Inputs --> External (light pen) or an internal device (touch overlay and controller) . COMPONENTS OF TOUCH SCREEN : COMPONENTS OF TOUCH SCREEN Three major components viz, Touch sensor Controller Software driver TOUCH SENSORS : TOUCH SENSORS Touch sensor Covering screen Contd.. : Contd.. Touch sensor --> In between clear glass panels. Responsive area --> Entire viewable area of the display screen. Sensors --> Detects electrical current or signal. Touching -->causes a voltage or signal change, thereby the location can be determined. CONTROLLER : CONTROLLER CONTD… : CONTD… PC card --> Touch sensor and the PC. Change in voltage --> Translated into the information that CPU understands. Translated bits --> Position where the touch occurs. Processor --> change the screen accordingly. SOFTWARE DRIVER : SOFTWARE DRIVER Acts as a bridge --> Screen and processor. Makes the operating system --> To interpret the touch event information. Touch screen drivers today --> Mouse-emulation type driver ( like touching the screen the same as clicking mouse) Recent research --> To make it as PNP TYPES OF TOUCH SCREEN : TYPES OF TOUCH SCREEN Resistive Touch screen Surface wave Touch screen Capacitive Touch screen Surface capacitive Projected capacitive Infrared Touch screen RESISTIVE TOUCH SCREENS : RESISTIVE TOUCH SCREENS RESISTIVE TOUCH SCREEN : RESISTIVE TOUCH SCREEN CONTD… : CONTD… 1. Polyester Film. 2. Top Resistive Layer. 3. Conductive Transparent Metal Coating. 4. Bottom Resistive Layer . 5. Insulating Dots . 6. Glass Substrate WORKING OF RESISTIVE SENSORS : WORKING OF RESISTIVE SENSORS Resistive touch screen monitor composed of : Flexible top layer Rigid bottom layer Insulating dots Along with touch screen controller. Top & Bottom layers --> transparent metal oxide coating. Pressure over the flexible top sheet --> Makes electrical contact between the resistive layers & the switch closing in the circuit. Controller --> Alternating voltages & converts them into the digital X and Y coordinates. CONTROLLER : CONTROLLER NAME: VS20UA CONTROLLER Supply Voltage 5.0V  DC Maximum Current  20mA Resolution 12-bit PROPERTIES : PROPERTIES 2 conductive layers that connects when touched. Capable of multi touch. Not affected by dirt or dust. Good for outdoor use. SURFACE WAVE TOUCH SCREEN : SURFACE WAVE TOUCH SCREEN SURFACE WAVE TOUCH SCREEN : SURFACE WAVE TOUCH SCREEN WORKING OF SURFACE WAVE SENSORS : WORKING OF SURFACE WAVE SENSORS Contains Transmitting and receiving transducers Touchscreen controller --> 5 MHz electrical signal to the transmitting transducer. Converts electrical signal --> ultrasonic waves within the glass. Waves --> Directed across the front surface of screen. Reflectors - -> Reflects & directs towards receiving transducer. Receiving transducer --> reconverts --> An electrical signal & digitally maps the touchscreen CONTROLLER : CONTROLLER NAME: 2701RSU CONTROLLER Voltage +5 VDC Baud Rate 9600 Touch Resolution 12bit, size independent Conversion Time 10 ms per coordinate set CAPACITIVE TOUCHSCREEN : CAPACITIVE TOUCHSCREEN CAPACITIVE TOUCHSCREEN : CAPACITIVE TOUCHSCREEN WORKING OF CAPACITIVE TOUCHSCREEN : WORKING OF CAPACITIVE TOUCHSCREEN Uniform conductive coating on a glass panel. Operation --> Electrodes around the panel's edge evenly distribute a low voltage across the conductive layer & creates an uniform electric field. Finger touch --> Draws current from each corner. Controller --> Measures ratio of the current flow from the corners & calculates the touch location. Capacitance --> Finger and the sensor grid. LAYERS OF CAPACITIVE TOUCHSCREEN : LAYERS OF CAPACITIVE TOUCHSCREEN Contains 3layers ,viz Front Protective glass Back protective glass - provides optical & strength enhancement options Middle layer - laminated sensor grid of micro-fine wires CONTROLLER : CONTROLLER Name: 5000 RSU SERIAL CONTROLLER Supply Voltage: +5 V DC or +12V Baud Rate 9600 (default) and 19200 Touch Resolution 12bit, size independent. Conversion Time Approximately 15 ms per coordinate set PROPERTIES : PROPERTIES Conductive coating that emits electric field. Very durable. Must be touched by some conductive materials. Capable of multi touch. PROS & CONS OF TOUCH SCREENS : PROS & CONS OF TOUCH SCREENS Direct pointing to the objects. Fast. Finger or pen is usable (No cable required) No keyboard necessary Suited to all interactive applications. Low precision when we use finger. Screen may be covered more by using hand No direct activation to the selected function PROS CONS applications : applications Public Information Displays::: Tourism displays Trade show display Awareness kiosks Customer Self-Services::: General departmental Stores Restaurants ATMs Airline ticket terminals, etc. Other uses::: Digital jukeboxes Computerized gaming Student Registration systems, etc. RECENT PRODUCT S UNDER DEVELOPEMENT : RECENT PRODUCT S UNDER DEVELOPEMENT Recent trends : Recent trends Introduction of i-PAN7: Flat Touchscreen computer - Panel PC Introduced by Keith & Koep of Japan. Small frame computer. Runs with Windows Embedded CE & built with low power ARM processor. Uses Capacitive touch panels. FEATURES OF i-PAN7 : FEATURES OF i-PAN7 WVGA (800 x 480) 7" Touchscreen. CPU 3.12MHz. 64 to 128MB RAM. Up to 2GByte embedded flash. 10/100 Ethernet. SD/MMC Card READER USB GPS, GPRS/GSM/SIM Camera 20 bit stereo out (headphone) Real Time Clock 8 inputs, 8 outputs (CPLD) 3 x 10Bit ADC UART (1-3 x) Fingerprint extension (SPI) Low Power consumption (typically 3-5W) Windows CE 5.0, Windows CE 6.0 R2 Dimension 169 mm x 108 mm x 17 mm IEEE 802.11bg WLAN. Bluetooth. conclusion : conclusion Though the Touch screen technology contains some limitations it’s user friendly. Fast. Accurate. easy to operate. It has been widely accepted and a little modification can replace the mouse and key board completely in near future. references : references Partridge, K., Chatterjee, S., Sazawal, V., Borriello, G. and Want, R. TiltType: Accelerometer-Supported Text Entry for Very Small Devices. Sazawal, V., Want, R. and Borriello, G. The Unigesture Approach One-Handed Text Entry for Small Devices. Wigdor, D., Balakrishnan, R. TiltText: Using Tilt for Text Input to Mobile Phones. Ward, D.J. Adaptive Computer Interafces. Ph.D. Thesis, University of Cambridge, 2001. Available at: Wobbrock, J.O., Myers, B.A., Kembel, J.A. EdgeWrite: A Stylus-Based Text Entry Method Designed for High Accuracy and Stability of Motion. THANK YOU : THANK YOU

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