Introduction Evolution Of Touch Screen Types Of Touch Screen IPOD Touch Screen
A Touchscreen is an electronic visual display that candetect the presence and location of a touch within thedisplay areaIt is an Input device that allows users to operate a PC bysimply touching the display screenA touch screen is based on CRT (Cathode Ray Tube)technology, SAW (Surface Acoustic Wave) technology,that accepts direct onscreen input.The ability for direct onscreen input is facilitated by anexternal (light pen) or an internal device (touch overlay andcontroller) .
How Does a Touchscreen Work?A basic touchscreen has three main components: Touch Sensor, Controller Software Driver.The touchscreen is an input device, so it needs to becombined with a display and a PC or other device toMake a complete touch input system.
A touch screen sensor is a clear glass panelwith a touch responsive surface.The sensor generally has an electrical currentor signal going through it and touching thescreen causes a voltage or signal change.This voltage change is used to determine thelocation of the touch to the screen.
The controller is a small PC card thatconnects between the touch sensorand the PC. It takes information fromthe touch sensor and translates it intoinformation that PC can understand.The controller determines what type ofinterface/connection you will need onthe PC.Controllers are available that canconnect to a Serial/COM port (PC) orto a USB port (PC or Macintosh).Specialized controllers are alsoavailable that work with DVD playersand other devices.
The driver is a software that allows the touchscreen and computer to work together. It tellsthe operating system how to interpret thetouch event information that is sent from thecontroller.Most touch screen drivers today are a mouse-emulation type driver. This makes touching thescreen the same as clicking your mouse at thesame location on the screen.This allows the touchscreen to work withexisting software and screen driver.
Resistive touch screen monitors are usuallymade up of a flexible top layer and a rigidbottom layer.The resistive touch screen monitors are verydurable and are not easily contaminated withitems that may interfere with the acousticwaves. Bottom Resistive Layer .Insulating Dots .Glass Substrate
A capacitive touchscreen panel is coatedwith a material, typicallyindium tin oxide thatconducts a continuouselectrical current acrossthe sensor. The sensor thereforeexhibits a preciselycontrolled field ofstored electrons in boththe horizontal andvertical axes - itachieves capacitance.
Surface acoustic wave(SAW) technology usesultrasonic waves that passover the touch screenpanel.When the panel is touched,a portion of the wave isabsorbed. This change inthe ultrasonic wavesregisters the position of thetouch event and sends thisinformation to the controllerfor processing.
An infrared (IR) touch screen panel employs one of two verydifferent methods. One method uses thermal induced changes of the surfaceresistance. This method is sometimes slow and requires warmhands.Another method is an array of vertical and horizontal IRsensors that detect the interruption of a modulated light beamnear the surface of the screen.IR touch screens have the most durable surfaces and are usedin many military applications that require a touch panel display.
iPod touch apart from other iPod models -- other than the latest nano -- is its touch-screen interface. When you touch the screen, the iPods circuitry detects the presenceof your finger. It keeps track of how many fingers you have on the screen and whereyou move them.
Top polyester coated with a transparentmetallic conductive coating on the bottomAdhesive layer on the backside of the glassfor mounting.Glass layer coated with a transparentmetallic conductive coating on the topAdhesive spacer