Touch screen technology


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Touch screen technology

  1. 1. Touch screen technology Researcher: Eng. Tamer Sherif Mohamed ElMasry. Supervisor: Prof.D. Mohamed Besheer
  2. 2. What are Touch Screens? <ul><li>It is the most user friendly input device used to interface with a PC. </li></ul><ul><li>The user touches the screen </li></ul><ul><li>to select options presented </li></ul><ul><li>on it, where associated hardware and software locate that touch. </li></ul>
  3. 3. History and Development <ul><li>In 1971 Dr. Sam Hurst, founder of Elographics developed the first touch opaque sensor “Elograph” at the University of Kentucky. </li></ul><ul><li>In 1974 He developed the first real touch screen. </li></ul><ul><li>In 1977, Elographics developed the five-wire resistive technology then with the backing of Siemens Corporation, developed a curved glass sensor called the touch screen . </li></ul><ul><li>The new transparent technology, AccuTouch, was later developed by the founders of Elographics, Dr. Hurst and Bill Colwell. </li></ul>
  4. 4. Why use Touch Screens? <ul><li>Enable first-time users to interface with computers instantly, without any training. </li></ul><ul><li>Eliminate operator errors because users make selections from clearly defined menus. </li></ul><ul><li>Eliminate keyboards and mice, which many novice users find difficult to use. </li></ul><ul><li>Rugged enough to stand up to harsh conditions where keyboards and mice can be damaged. </li></ul><ul><li>Provide fast access to all types of digital content. </li></ul><ul><li>Ensure that no space is wasted since the input device is completely integrated into the monitor. </li></ul>
  5. 5. Elements of a touchscreen system <ul><li>The touchscreen itself. </li></ul><ul><li>A computer whose display is fitted with the touchscreen interefacing with. </li></ul><ul><li>A controller drives the touchscreen and converts each touch into X/Y coordinates. </li></ul><ul><li>A software driver, which communicates between the controller card and the computer's operating system. </li></ul><ul><li>Application-development software, which enables developers of touch programs to build their own applications and/or customize existing touch applications. </li></ul>
  6. 6. How do Touchscreens Work?
  7. 7. TOUCH TECHNOLOGIES <ul><li>Here are some technologies that are used in making touch screens: </li></ul><ul><ul><li>Resistive </li></ul></ul><ul><ul><li>Capacitive </li></ul></ul><ul><ul><li>Surface Acoustic Wave (SAW) </li></ul></ul><ul><ul><li>Scanning Infrared </li></ul></ul><ul><ul><li>Near Field Imaging </li></ul></ul>
  8. 8. Resistive touch screen <ul><li>Made of a glass panel with a coating of uniform resistivity on which a voltage is applied. A polyester cover sheet is tightly suspended over the top of the glass, separated from it by small, transparent insulating dots. </li></ul><ul><li>The cover sheet has a hard, durable coating on the outer side and a conductive coating on the inner side. </li></ul>
  9. 9. <ul><li>With a light touch, the conductive coating makes electrical contact with the coating on the glass. </li></ul><ul><li>  The voltages at the point ofcontact are the analog representation of the position touched. The controller digitizes these voltages and transmits them to the computer for processing. </li></ul>
  10. 10. <ul><li>Advantages of Resistive </li></ul><ul><li>High Resolution and Accuracy </li></ul><ul><li>Fast Response </li></ul><ul><li>Pressure-activated by finger or gloved hand with a very light touch </li></ul><ul><li>Durable hard-coat front surface can be nonglare treated for     reflection control or polished for maximum clarity </li></ul><ul><li>Touchscreens and controllers are safety agency-approved components,so certification of your system is easier </li></ul><ul><li>Disadvantages of Resistive </li></ul><ul><li>80 % Clarity </li></ul><ul><li>Resistive layers can be damaged by a sharp object </li></ul>
  11. 11. Capacitive Touch screen <ul><li>There are 2 types of capacitive touch screens: </li></ul><ul><li>Surface capacitive </li></ul><ul><li>-consists of a uniform conductive coating on a glass panel on which a low voltage is evenly applied fromthe corners. </li></ul><ul><li>-The touch location is measured from the ratio of the current flow from the corners </li></ul>
  12. 13. <ul><li>Projected Capacitive </li></ul><ul><li>-Made of a front and back protective glass providing optical and strength enhancement options. </li></ul><ul><li>-Its middle layer consists of a laminated sensor grid of micro-fine wires and optical enhancement options. </li></ul>
  13. 14. <ul><li>Advantages of Capacitive </li></ul><ul><li>High Touch Resolution </li></ul><ul><li>High Clarity </li></ul><ul><li>Completely Sealable </li></ul><ul><li>Disadvantages of Capacitive   </li></ul><ul><li>Must be touched by finger- will not work with any non- conductive input </li></ul><ul><li>Can be affected by electricity </li></ul><ul><li>May need re-calibration often </li></ul>
  14. 15. Surface Acoustic Wave Touch screen <ul><li>Made of a glass overlay with transmitting and receiving piezoelectric transducers for both the X and Y axes. </li></ul><ul><li>When a touch occurs, the wave is absorbed shortening the echo time it takes to reach the receivers. </li></ul>
  15. 16. <ul><li>Advantages of Surface Acoustic Wave </li></ul><ul><ul><li>Excellent Image Clarity -Very High LightTransmission </li></ul></ul><ul><ul><li>Excellent Durability -Stable &quot;No-Drift&quot; Operation </li></ul></ul><ul><ul><li>High Resolution - Very Light Touch </li></ul></ul><ul><ul><li>Fast Touch Response -X,Y and Z-axis Response </li></ul></ul><ul><ul><li>Finger or Gloved-Hand Operation </li></ul></ul><ul><li>Disadvantages of Surface Acoustic Wave </li></ul><ul><ul><li>Must be touched by finger, gloved hand, or soft-tip stylus.  Something hard like a pen won't work </li></ul></ul><ul><ul><li>Not completely sealable, can be affected by large  amounts of grease, water,  or dirt on the touchscreen </li></ul></ul>
  16. 17. Scanning Infrared touch screen <ul><li>Made of a grid of LEDs and detectors framed to the front of the display that projects horizontal and vertical beams of infrared light. </li></ul><ul><li>The press location is determined since it obstructs the IR beam </li></ul>
  17. 18. <ul><li>Advantages </li></ul><ul><li>Mostly used in manufacturing and medical applications since it can be completely sealed. </li></ul><ul><li>operated using a stylus or a gloved finger. </li></ul><ul><li>mechanically stronger </li></ul><ul><li>Clearer </li></ul><ul><li>more wear resistant </li></ul><ul><li>Disadvantages </li></ul><ul><li>it is very sensitive and can be activated by stray touches. </li></ul><ul><li>Low resolution </li></ul><ul><li>Parallax problems </li></ul>
  18. 19. Near Field Imaging touch screen <ul><li>Made of two laminated glass sheets having a transparent metal oxide coating in between. </li></ul><ul><li>An AC signal is applied to the patterned conductive coating creating an electrostatic field on the surface of the screen. </li></ul><ul><li>It is used only in the toughest environments and applications due to its high cost. </li></ul>
  19. 20. Applications of Touch Screens   <ul><ul><ul><li>Informational kiosks </li></ul></ul></ul><ul><ul><ul><li>Trade show displays </li></ul></ul></ul><ul><ul><ul><li>Museum / tourism displays </li></ul></ul></ul><ul><ul><ul><li>Point-of-sale terminals </li></ul></ul></ul><ul><ul><ul><li>Restaurant systems </li></ul></ul></ul><ul><ul><ul><li>Employee time clocks </li></ul></ul></ul><ul><ul><ul><li>Industrial process controls </li></ul></ul></ul><ul><ul><ul><li>World Wide Web access kiosks </li></ul></ul></ul><ul><ul><ul><li>Home automation systems </li></ul></ul></ul><ul><ul><ul><li>Casino and other gaming systems </li></ul></ul></ul><ul><ul><ul><li>Computer access for the physically disabled </li></ul></ul></ul>
  20. 21. Thank you
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