Different technical principles between touch screen

Touch screen Kiosk needs little storage space, few mobile parts, and can be packaged. Touch screen is more intuitive to use than keyboard and mouse, and the training cost is very low.

All touch screen have three main components. A sensor unit for processing user’s selection; And a controller for sensing touch and positioning, and a software drive for transmitting a touch signal to a operating system. There are five kinds of sensor technology in touch screen kiosk: resistance technology, capacitance technology, infrared technology, acoustic technology or near-field imaging technology.

Resistive touch screen usually include a flexible top layer film and a layer of glass as the base layer, which is isolated by insulation points. The inner surface coating of each layer is transparent metal oxide. There is a difference in voltage at each diaphragm. Pressing the top film will form an electrical contact signal between the resistance layers.

The capacitive touch screen is also coated with transparent metal oxide and bonded to a single glass surface. Unlike the resistive touch screen, any touch will form a signal, and the capacitive touch screen needs to be directly touched by fingers or conductive iron pen. The capacitance of the finger, or the ability to store charge, can absorb the current of each corner of the touch screen, and the current flowing through the four electrodes is proportional to the distance from the finger to the four corners, so as to get the touch point.

Infrared touch screen based on light interruption technology. Instead of placing a thin film layer in front of the display surface, it sets an outer frame around the display. The outer frame has light source, or light emitting diode (LED), which is located on one side of the outer frame, while the light detector or photoelectric sensor is on the other side, forming a vertical and horizontal cross infrared grid. When an object touches the display screen, the invisible light is interrupted, and the photoelectric sensor cannot receive the signal, so as to determine the touch signal.

In the acoustic sensor, the sensor is installed on the edge of the glass screen to send ultrasonic signals. The ultrasonic wave is reflected through the screen and received by the sensor, and the received signal is weakened. In surface acoustic wave (SAW), light wave passes through the surface of glass; Guided acoustic wave (GAW) technology, the sound wave through the glass.

Near field imaging (NFI) touch screen is composed of two thin glass layers with transparent metal oxide coating in the middle. An AC signal is applied to the coating at the guide point to generate an electric field on the surface of the screen. When a finger, with or without gloves, or other conductive pen contacts the sensor, the electric field is disturbed and the signal is obtained.

As the current mainstream touch technology, capacitive touch screen kiosk(all-in-one PC) not only has beautiful appearance and structure, but also has flow arc design. It has smooth picture in use, and ten fingers operate at the same time. LAYSON’s touch screen kisok is more competitive.

 

 


Post time: May-26-2021