18UE1A0401 technical seminar.pptx
- 2. Presented By T. Anusha Pin no: 18UE1A0401 Btech 4th year first sem Electronic communication & eng ineering • Trinity college of engineering & tec hnology
- 3. TALK FLOW INTRODUCTION HISTORY FUNCTIONS WORKING DIFFRENT TOUCH SCREEN TECHNOL OGIES APPLICATION CONCLUSION
- 4. INTRODUCTION A touch screen is a computer display screen that is sensitive to human touch, allowing a user to interact with the computer by touchi ng pictures or words on the screen. A touch screen is an input device that allows users to operate a PC by simply touching th e display screen which has a sensitive glass o verlay placed on it . A touch screen accepts direct onscreen inpu ts.
- 5. 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 Foundat ion named it as “Elograph”. The "Elograph" was not transparent like moder n touch screens. In 1974, the first true touch screen incorporatin g a transparent surface came.
- 6. FUNCTIONS OF TOUCH S CREEN Pressure sensitive activation-by finger or stylu s. Emulates mouse functions-click, double click, & drag. Touch screen & mouse can be used concurrent ly. Durable & scratch resistant coated surface. Compatible with Windows 95,98,NT,2000,XP, Macintosh,Linux.
- 7. HOW DOES A TOUCHSCREEN W ORKS? A basic touch screen has three main compo nents: touch sensor controller software driver
- 8. 1.TOUCH SENSOR A touch screen sensor is a clear glass panel wit h a touch responsive surface which is placed o ver a display screen. The sensor generally has an electrical current o r signal going through it and touching the scree n causes a voltage or signal change. This volta ge change is used to determine the location of t he touch to the screen.
- 10. 2.CONTROLLER The controller is a small PC card that connects b etween the touch senso r and the PC. It takes information fro m the touch sensor and translates it into inform ation that PC can under stand.
- 11. 3.SOFTWARE DRIVER The driver is a software that allows the touch s creen and computer to work together. It tells the operating system how to interpret th e touch event information that is sent from the controller. Most touch screen drivers today are mouse-e mulation type drivers. This makes touching the screen the same as clicking your mouse at the s ame location on the screen.
- 13. DIFFERENT TOUCH SCREEN TECHNOLOGIES RESISTIVE CAPACITIVE SURFACE WAVE INFRARED DISPERSIVE SIGNAL TECHNOLO GY
- 14. RESISTIVE TOUCH SCREEN TECHN OLOGY 1. Polyester Film . 2. Top Resistive Layer. 3. Conductive Transparent Metal Coating. 4. Bottom Resistive Layer . 5. Insulating Dots . 6. Glass Substrate
- 16. Contd. Pressing the flexible top sheet creates electrical contact with the coating on the glass. The touch screen controller gets the alternatin g voltages between the two layers and converts them into the digital X and Y coordinates of th e activated area.
- 17. Advantages of Resistive Technolo gy Can be activated with any device Low cost solution Low power consumption
- 18. Disadvantages of Resistive Techn ology Poorer durability compared to other techn ologies Very short life, especially considering co smetic wear
- 19. CAPACITIVE TOUCH SCREEN TECHN OLOGY In the capacitive system, a layer that stores el ectrical charge is placed on the glass panel. When a user touches, some of the charge is tran sferred to the user, so the charge on the capaciti ve layer decreases. This decrease is measured in electrodes located at each corner of the monitor. The computer then calculates the coordinates, fr om the relative differences in charge at each cor ner.
- 20. Contd. A finger touch draws current from each co rner. Then the controller measures the ratio o f the current flow fro m the corners and ca lculates the touch lo cation
- 21. Capacitive Technology ADVANTAGES More durable than resistive Higher transmittan ce than resistive DISADVANTAGES Accepts input from finger only. Accuracy is depen dent on capacitanc e of person
- 22. SURFACE WAVE TECHNOLO GY It has a transmitting and receiving transducers for bot h the X and Y axes. The touchscreen controller sends a five-megahertz ele ctrical signal to the transmitting transducer, which co nverts the signal into ultrasonic waves within the glas s. These waves are directed across the front surface of t he touchscreen by an array of reflectors.
- 24. Contd. Reflectors on the opposite side gather and dire ct the waves to the receiving transducer, which reconverts them into an electrical signal. When you touch the screen, you absorb a porti on of the wave travelling across it. The receivers can detect a drop in amplitude a nd thus coordinate is calculated.
- 25. ADVANTAGES Very high transmittan ce Very high durability DISADVANTAGES Requires “soft” input device Surface obstructions c an cause a false touc h
- 26. INFRARED TOUCH SCREEN TECH NOLOGY IR makes use of a “frame” around the perimete r 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 si gnal is read from the matching transistor. If no signal is read, then that indicates a blocked IR beam, meaning a touch.
- 28. ADVANTAGES Highest quality of unde rlying image Very high transmittanc e Very high durability and reliability DISADVANTAGES Lower resolution than o ther technologies Surface obstructions ca n cause a false touch
- 29. DISPERSIVE SIGNAL TECHNOL OGY This is the recent most techn ology, introduced in 2002. It uses sensors to detect the mechanical (vibrational)ener gy in the glass that occur du e to a touch. Complex algorithms then int erpret this information and provide the actual location o f the touch.
- 30. 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 syste ms, multimedia software, financial and scien tific applications, and more.
- 31. CONCLUSION Touchscreens, touch panels or touchscreen pan els are display overlays which have the ability to display and receive information on the same screen. Touchscreens also have assisted in recent cha nges in the PDAs, making these devices more usable.