一篇英文关于触摸屏的综述性文章，总结了电阻触摸屏，电容式触摸屏，红外式触摸屏，表面声波式触摸屏的一些特点，没有太多特别的地方，但是如果你想总结这几种触摸屏的优点缺点的话，倒是具有一定的参考价值哦
Resistive
This paper will not attempt to discuss all the various flavors of resistive (4-wire, 5-wire, 7-wire, and 8-wire), as they all fundamentally have the same operation. The sensor consists of a piece of glass with a conductive coating on top, plus a polyester top sheet with a conductive coating on the bottom. The conductive surfaces are held apart by “spacer dots”, usually glass beads that are silk-screened onto the coated glass. On a 5-wire design (the most commonly used type of resistive in large screen POS applications); a voltage is applied to the 4 corners of the glass layer. When a person presses on the top sheet, it is deformed and its conductive side comes in contact with the conductive side of the glass, effectively closing a circuit. The voltage at the point of contact is read from a wire connected to the top sheet.
Capacitive
The capacitive sensor has a conductive coating on the front surface with wires connected to each corner. A small voltage is applied to each of these 4 corners. The operation relies on the capacitance of the human body. When a person touches the screen, a small current flows to the point of touch, causing a voltage drop which is sensed at the 4 corners.
Surface Acoustic Wave (SAW)
A SAW touch screen consists of a piece of glass with “sound wave reflectors” deposited along all 4 edges. Two emitting transducers are mounted in two corners and receivers are mounted in the opposing two corners. A sound wave travels parallel to the borders of the glass. As it encounters the sound wave reflectors, some of it is passed through to the next sound wave reflector, and some of it is reflected across the touch screen. On the opposite side, the wave is passed through the sound wave reflectors to the receivers. The receivers can detect a drop in amplitude of the sound wave when a sound absorbing material (such as a finger) is placed in contact with the glass.
Scanning Infra Red (IR)
IR uses of a Printed Circuit Board (PCB) “frame” around the perimeter 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 signal is read from the matching transistor. If no signal is read, then that indicates a blocked IR beam, meaning a touch. No actual touch “screen” is required for operation, however a plate of glass is generally used to protect the underlying display from damage and to provide anti-glare.
