Infrared touch screen: infrared technology touch screen mounted on the screen frame of infrared transmission and reception sensing elements, forming an infrared detection network on the surface of the screen, any touching objects can change the infrared on the touch points and realize the touch screen operation. In the infrared touch screen, the screen on all four sides of the circuit board lined up devices with infrared transmitter tube and infrared receiver tube, corresponding to the formation of horizontal and vertical cross infrared matrix.
Infrared touch screen is not subject to current, voltage and static interference, suitable for a variety of harsh environments. Its main advantages are low price, easy to install, excellent stability, long service life, high transmittance (up to 95%), no drift, no drive, no calibration, plug and play, but also maintain a clear and transparent image, can be used in a variety of equipment, such as advertising machines, query machines and so on.
Electromagnetic touch screen: The basic principle of electromagnetic touch screen is to rely on the electromagnetic pen and inductor in the operation process of the magnetic field generated by the change to discriminate, electromagnetic pen for the signal transmitter (transceiver), antenna plate for the signal receiver (receiver), when close to the induction of magnetic flux changes, followed by the operation of the definition of the position point. The magnetic flux changes when close to the induction, and then the position point is defined by the operation.
The electromagnetic touch screen is more costly, has high light transmission and resolution, and has Z-axis sensing capability, which allows touch control without touching. The handwriting recognition feature, coupled with the high precision of the electromagnetic stylus, is perfect for underlining, annotating, and note-taking in text gaps, which is why it is used in the mid-to-high-end versions of the Davinci Board. The downside is that it relies on the stylus's electromagnetic emission to orient itself, and you must use an electromagnetic pen when operating it.
Capacitive touchscreens: Capacitive touchscreens have narrow electrodes plated on all four sides, creating a low-voltage AC field inside. The screen is covered with a layer of transparent film layer of metal conductive material, when the user touches the capacitive screen finger and the work surface will form a coupling capacitance, so the finger will suck a part of the electrodes from the four corners of the screen out of the current. Because the current flowing through the four electrodes is proportional to the distance from the finger to the four corners, the controller can calculate the position of the contact point through a precise calculation of the ratio of the four currents.
The capacitive touch screen utilizes the current generated when the biotech and the screen are in contact to locate, so it is operated with the finger, but non-biological organisms such as fingernails and pens cannot be operated. As capacitance varies with temperature, humidity and grounding, drift occurs. Capacitive touch panels have a low yield and a small size range, resulting in high prices and limited mass production. However, it is precise, responsive, and durable (scratch-resistant), so it is more suitable for high-precision devices, such as Apple's IPhone