Surface acoustic wave (SAW) is a kind of ultrasonic wave, which is a kind of mechanical energy wave propagating on the surface of medium (such as rigid materials such as glass or metal). Through the wedge-shaped triangular base (designed strictly according to the wavelength of surface wave), directional and small-angle surface acoustic wave energy emission can be realized.
Surface acoustic wave (SAW) is stable and easy to analyze, and has very sharp frequency characteristics in the process of shear wave propagation. In recent years, its application in nondestructive testing, imaging, wave eliminator and other aspects has developed rapidly, and the related theoretical research, semiconductor materials, acoustic conductive materials, detection technology and other technologies have been quite mature.
The touch screen part of the surface acoustic wave touch screen can be a flat, spherical or cylindrical glass plate, which is installed in front of CRT, led, LCD or plasma display screen. This glass plate is just a pure tempered glass, which is different from other touch screen technologies in that there is no film and cover.
Vertical and horizontal ultrasonic transmitting transducers are fixed at the upper left corner and the lower right corner of the glass screen, and two corresponding ultrasonic receiving transducers are fixed at the upper right corner. The glass screen is surrounded by reflective stripes with an angle of 45 degrees from sparse to dense.
Infrared touch screen:
Infrared touch screen has many invention patents, such as the structure and method to improve the performance of infrared touch screen, integrated infrared touch display, infrared touch screen optical system and so on.
The working principle of infrared touch screen is that infrared receiving tubes and infrared emitting tubes are distributed around the touch screen, and these infrared tubes are arranged on the surface of the touch screen in a one-to-one relationship, forming an optical network composed of infrared rays. When an object (which can be a finger, a gloved hand or any touching object) enters the infrared network to block the infrared emission and reception somewhere, the infrared intensity received by the receiving infrared tube will change in the horizontal and vertical directions, and the equipment can know by knowing the change of infrared reception.
Through hardware design and software programming, the infrared touch screen can interpolate the data of each point, and the resolution can reach 4096×4096.
Because of the working principle of the infrared touch screen itself, it can be touched without pressure (referring to the pressure exerted by the touch body on the touch screen itself), so it can work without wearing glass.
At the same time when the infrared touch screen works, only a pair of infrared tubes (referring to the transmitting tube and the receiving tube corresponding to the physical position) are doing data work, and the circuit achieves the effect of rapid response by collecting the high-frequency data of the infrared tubes.
The light transmittance of resistance screen is not as good as that of surface acoustic wave and infrared, so it is afraid of scratching.