Touch Screen And Graphical Tablet Basit Ali Bukhari (Group Leader) Ahsan Iqbal Muhammad Ahmed Yousuf Shah Group members Touch ScreenGraphical TabletQuestions n Answers Menu Graphical tablet A graphics tablet is a computer input device that enables a user to hand- draw images, animations and graphics, similar to the way a person draws images with a pencil and paper. Whats a graphical tablet? How does it work? The tablet works when a user draws a line with the stylus, the drawing does not show up on the tablet. Instead the action generates a signal that goes to a vertical grid of wires running across the tablet. By using electromagnetic signals, the tablet is able to transfer the lines to the computer screen or display being used. Graphics tablets are very commonly found in the artistic world. Using a pen on a graphics tablet combined with a graphics-editing program, such as Adobe Photoshop, gives artists a lot of precision while creating digital drawings. Photographers can also find working with a graphics tablet during their post processing. Educators make use of tablets in classrooms to project handwritten notes or lessons and to allow students to do the same, as well as providing feedback on student work submitted electronically. Online teachers may also use a tablet for marking student work or for solving mathematical equations. Where is it used? Benefits A benefit for graphics artists. More effective than mouse input. Natural to use for anyone familiar with a pen. Can record levels of pressure unlike other point and click devices. Can come in different sizes. Drawbacks Slower then paper drawing. Can be awkward to access menus and make selections. Larger designs (A4 for example) are expensive. Mouse feels cheap, tricky to get the hang of. Menu Touch screen A touch screen is an electronic visual display that the user can control through simple or multi-touch gestures by touching the screen with a special stylus/pen and-or one or more fingers. Whats a touch screen? Touch screens are used almost everywhere, like in restaurants, many phones consist of touchscreens as well as tablets and laptops & ATM machines also have touch screens. Where is it used? One of the main uses of touchscreen technology is in mobile phones. There are three major types of touchscreen technologies: CapacitiveInfra-redResistive Types of Touchscreens This is made up of many layers of glass that act like a capacitor, creating electric fields between the glass plates in layer. When the top glass layer is touched, the electric current changes and the coordinates where the screen was touched is determined by an on-board microprocessor. Capacitive This is a medium cost technology. Scree visibility is good even in strong sunlight. It permits multi-touch compatibility. The screen is very durable; it takes a major impact to break the glass. Benefits Allows only the use of bare fingers as the form of input; although the latest screens permit stylus to be used. Drawback Heat-sensitive Uses glass as the screen material. Needs a warm object (e.g. fingers) to carry out an input operation. Optical Uses glass as a screen material. Uses an array of sensors (in the form of grid); the point of contact is based on which grid coordinate is touched. Infra-red (heat and optical) Both systems allow multi-touch capabilities. The optical system allows the use of bare fingers, glove fingers or stylus for input. Both systems have good screen durability; it takes a major impact to break the glass. Benefits It is relatively expensive technology. Heat-sensitive system only allows bare fingers to be used for input. Both systems have fairly good screen visibility in strong sunlight. Drawbacks This makes use of an upper layer of polyester and a bottom layer of glass. When the top polyester layer id touched, the top layer and the bottom layer complete a circuit. Signals are then sent out which are interpreted by a microprocessor, the calculations determine the coordinates of where the screen was touched. Resistive It is relatively inexpensive technology. It is possible to use bare fingers, gloved fingers or a stylus to carry out an input operation. Benefits Screen visibility is poor in strong sunlight. It doesnt permit multi-touch capability. The screen durability is only fair; it is vulnerable to scratches and the screen wears out tough time. Drawbacks Menu Questions n answers