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 Three major components viz, Touch sensor Controller Software driver
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.
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 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
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 NAME: VS20UA CONTROLLER Supply Voltage 5.0V DC Maximum Current 20mA Resolution 12-bit
PROPERTIES2 conductive layers that connects when touched. Capable of multi touch. Not affected by dirt or dust. Good for outdoor use.
WORKING OF SURFACE WAVE SENSORS Contains Transmitting and receiving transducers Touch screen 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 touch screen
CONTROLLER NAME: 2701RSU CONTROLLER Voltage +5 VDC Baud Rate 9600 Touch Resolution 12bit, size independent Conversion Time 10 ms per coordinate set
WORKING OF CAPACITIVE TOUCHSCREEN Uniform conductive coating on a glass panel. Operation --> Electrodes around the panels 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.
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 Conductive coating that emits electric field. Very durable. Must be touched by some conductive materials. Capable of multi touch.
PROS & CONS OF TOUCH SCREENSPROS CONS Direct pointing to the Low precision when we use objects. finger. Fast. Screen may be covered Finger or pen is usable (No more by using hand cable required) No direct activation to the No keyboard necessary selected function Suited to all interactive 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.
EXCLUSIVE HIGH PERFORMANCEOF TOUCH SCREEN TECHNOLOGY High resolution enhanced infraredBENEFITS1:Easier to pin point2:Better drag and drop3:Extra resolution4:Better sensitivity to environment
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.
DISADVANTAGES User hand’s may obscure the screen Screens need to be installed at lower position and tilted to reduce arm fatigue Some reduction in image brightness may occur They cost more than alternative devices
HOW IS TOUCH SCREEN DIFFERENTFROM OTHER DEVICES No special commands to learn No use of keyboards Entering wrong information is impossible No fear of damage or lost of loose hardware pieces
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.