Touch Screen Technology Review 16 February 2014 UNIVERISTY OF TURKISH AERONAUTICAL ASSOCIATION Department of Electrical and Electronics Engineering EEE 512 : Sensors & Signal Conditioning Touch Screen Technology Review Presented by : Hamza Emhemed Hebrisha ID: 1606030005 Email: hamzaheb@yahoo.com Supervisor: Dr. Hassan SHARABATY hsharabaty@thk.edu.tr Ankara - December 2016

Touch Screen Technology 16 February 2014 Contents Introduction. History and Development. Components of Touch Screen. Types of Touch Screen Technologies. Advantages & Disadvantage. Applications. Future Scope. Conclusion. Eng : Hamza Hebrisha Touch Screen Technology

Touch Screen Technology 16 February 2014 Introduction A touch screen is a computer display screen that is sensitive to human touch, allowing a user to interact with the computer by touching pictures or words on the screen. A touch screen is an input device that allows users to operate a PC by simply touching the display screen which has a sensitive glass overlay placed on it. A touch screen accepts direct onscreen inputs. Eng : Hamza Hebrisha Touch Screen Technology

History and Development 16 February 2014 History and Development In 1971 Dr. Sam Hurst, founder of Elographics developed the first touch opaque sensor “Elograph” at the University of Kentucky. In 1974 He developed the first real touch screen. 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. Eng : Hamza Hebrisha Touch Screen Technology

Components of Touch Screen 16 February 2014 Components of Touch Screen A basic touch screen has three main components: 1. Touch Sensor 2. Controller 3. Software Driver Eng : Hamza Hebrisha Touch Screen Technology

Touch Screen Technology 16 February 2014 1. Touch Sensor The sensor generally has an electrical current or signal going through it and touching the screen causes a voltage or signal change. A touch screen sensor is a clear glass panel with a touch responsive surface which is placed over a display screen. Eng : Hamza Hebrisha Touch Screen Technology

Touch Screen Technology 16 February 2014 2. Controller The controller is a small PC card that connects between the touch sensor and the computer. It takes information from the touch sensor and translates it into information that computer can understand. Eng : Hamza Hebrisha Touch Screen Technology

Touch Screen Technology 16 February 2014 3. Software Driver The driver is a software that allows the touch screen and computer to work together. It tells the operating system how to interpret the touch event information that is sent from the controller. Most touch screen drivers today are mouse-emulation type drivers. This makes touching the screen the same as clicking your mouse at the same location on the screen. Eng : Hamza Hebrisha Touch Screen Technology

Diagram showing How it Works Touch Screen Technology 16 February 2014 Diagram showing How it Works Eng : Hamza Hebrisha Touch Screen Technology

Types of Touch Screen Technologies: A- Resistive Touch Screen. B- Capacitive Touch Screen. C- Surface Acoustic Wave Touch screen (SAW). D- Infrared Touch Screen. Eng : Hamza Hebrisha Touch Screen Technology

A- Resistive Touch Screen A resistive touch screen panel is composed of several layers, the most important of which are two thin metallic electrically conductive layers separated by a narrow gap. When an object, such as a finger, presses down on a point, causes a change in the electrical current, which is registered as a touch event and sent to the controller for processing. Eng : Hamza Hebrisha Touch Screen Technology

Advantages And Disadvantages of Resistive Cost-effective . Activated by any stylus. Very accurate. Low power requirements. Liquids won’t affect touch screen performance. Polyester surface can be damaged . Poorer durability compared to other technologies . Eng : Hamza Hebrisha Touch Screen Technology

B- Capacitive Touch Screen A capacitive touch screen panel consist of an insulator such as glass, coated with a transparent conductor such as indium tin oxide(ITO). As the human body is also a conductor, touching the surface of the screen results in a distortion of the body’s electrostatic field , measurable as a change in capacitance Eng : Hamza Hebrisha Touch Screen Technology

Touch Screen Technology Capacitive Touch Screen: 1. Surface Capacitive Touch Screen. 2. projected Capacitive Touch Screen. 1. Surface Capacitive Touch Screen. Surface capacitive technology consists of a uniform conductive coating on a glass panel. Eng : Hamza Hebrisha Touch Screen Technology

2. projected Capacitive Touch Screen The design of projected capacitive touch screen is somewhat similar to that of resistive touch screens. An XY array is formed either by etching a single layer to form a grid pattern of electrodes, or by etching two separate, perpendicular layers of conductive material with parallel lines or tracks to form the grid. Eng : Hamza Hebrisha Touch Screen Technology

Advantages and Disadvantages Of Capacitive Projected - capacitive panels have multiple sensors Scratch resistance, Durable surface. Very accurate. Good optical clarity. Liquid won’t affect touch screen performance . Does not work with gloved fingers Accepts input from finger only. Eng : Hamza Hebrisha Touch Screen Technology

C- Surface Acoustic Wave Touch screen (SAW) Surface Acoustic Wave (SAW) technology uses ultrasonic waves that pass over the touch screen panel. When the panel is touched, a portion of the wave is absorbed. The change in the ultrasonic waves registers the position of the touch event and sends this information to the controller for processing. Eng : Hamza Hebrisha Touch Screen Technology

Advantages and Disadvantages of SAW Better clarity than Resistive and Capacitive Work almost with any stylus Very high scratch immunity can be deployed to a curved surface provides superior resolution Must use soft object to enable touch Low weather immunity (water and dust) Cannot be completely sealed require periodic cleaning of sensor can be activated inadvertently by dirt Eng : Hamza Hebrisha Touch Screen Technology

D- Infrared Touch Screen An infrared touch screen uses an array of X-Y infrared LED and photo detector pairs around the edges of the pattern of LED beams. Infra-red bezels have proven to be a very reliable technology for use in ATMs, Medical Instrumentation and Transportation Tracking applications. Eng : Hamza Hebrisha Touch Screen Technology

Advantages and Disadvantages of Infrared Touch Screen It is very sensitive & can be activated by stray touches. Low resolution. Highest quality of underlying image. Very high transmittance. Can be activated with almost any device. Higher accuracy than other technologies. Very high durability and reliability. Eng : Hamza Hebrisha Touch Screen Technology

Advantages for Touch screen Touch Screen Technology 16 February 2014 Advantages for Touch screen High touch resolution. High image clarity. Not affected by contaminant. User friendly. Fast response. Error free input. No keyboard necessary. Eng : Hamza Hebrisha Touch Screen Technology

Disadvantages for Touch Screen Touch Screen Technology 16 February 2014 Disadvantages for Touch Screen Finger stress. Fingerprints. Accepts input from finger only.                      big screen leads to low battery life. Eng : Hamza Hebrisha Touch Screen Technology

Touch Screen Technology 16 February 2014 Applications ATMs. Phones. Computers. Gaming machines. Point of Sale Industrial controls. Hand held electronics. Eng : Hamza Hebrisha Touch Screen Technology

Touch Screen Technology Future Scope Wood touch Touch screen Video Projectors. Eng : Hamza Hebrisha Touch Screen Technology

Touch Screen Technology 16 February 2014 Conclusion Touch systems represent a rapidly growing subset of the display market. The majority of touch systems include touch sensors relying on vacuum-deposited coatings, so touch coatings present opportunity for suppliers of vacuum coatings and coating equipments. Touch sensor manufactures currently require thin films in the areas of transparent conductors, optical interference coating and mechanical protective coatings. Eng : Hamza Hebrisha Touch Screen Technology

Touch Screen Technology 16 February 2014 Thank You Eng : Hamza Hebrisha Touch Screen Technology