Touch screen technology

1. TOUCH SCREEN TECHNOLOGY

2. definition What is touch screen

3. 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) .

4. COMPONENTS OF TOUCH SCREEN Three major components viz , Touch sensor Controller Software driver

5. TOUCH SENSORS Touch sensor Covering screen

6. 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.

7. CONTROLLER

8. CONTD… PC card --> T ouch 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.

9. 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

10. TYPES OF TOUCH SCREEN Resistive Touch screen Surface wave Touch screen Capacitive Touch screen Surface capacitive Projected capacitive Infrared Touch screen

11. RESISTIVE TOUCH SCREENS

12. RESISTIVE TOUCH SCREEN

13. CONTD… 1. Polyester Film. 2. Top Resistive Layer. 3. Conductive Transparent Metal Coating. 4. Bottom Resistive Layer . 5. Insulating Dots . 6. Glass Substrate

14. 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.

15. CONTROLLER NAME: VS20UA CONTROLLER Supply Voltage 5.0V  DC Maximum Current   20mA Resolution 12-bit

16. PROPERTIES 2 conductive layers that connects when touched. Capable of multi touch. Not affected by dirt or dust. Good for outdoor use.

17. SURFACE WAVE TOUCH SCREEN Introduction

18. SURFACE WAVE TOUCH SCREEN

19. 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 --> D irected across the front surface of screen. Reflectors - -> Reflects & directs towards receiving transducer. Receiving transducer --> reconverts --> An electrical signal & digitally maps the touch screen

20. CONTROLLER NAME: 2701RSU CONTROLLER Voltage +5 VDC Baud Rate 9600 Touch Resolution 12bit, size independent Conversion Time 10 ms per coordinate set

21. CAPACITIVE TOUCHSCREEN Introduction

22. CAPACITIVE TOUCHSCREEN Figure

23. 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.

24. LAYERS OF CAPACITIVE TOUCHSCREEN Contains 3layers , viz Front Protective glass Back protective glass - provides optical & strength enhancement options Middle layer laminated sensor grid micro-fine wires

25. 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

26. PROPERTIES Conductive coating that emits electric field. Very durable. Must be touched by some conductive materials. Capable of multi touch.

27. 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

28. 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.

29. EXCLUSIVE HIGH PERFORMANCE OF TOUCH SCREEN TECHNOLOGY High resolution enhanced infrared BENEFITS 1:Easier to pin point 2:Better drag and drop 3:Extra resolution 4:Better sensitivity to environment

30. RECENT PRODUCT S UNDER DEVELOPEMENT

31. 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.

32. 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

33. How is touch screen different from 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

34. 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.