Basic Technologies

The touch screen is an absolute coordinate system. The current positioning coordinates have no relationship with the last positioning coordinates. The data of each touch is directly converted into coordinates on the screen through calibration. No matter what the situation is, the coordinate system of the touch screen is stable for the output data of the same point.

However, it does not guarantee that the sampling of the same touch point is the same every time. It cannot guarantee absolute coordinate positioning. This is the so-called drift problem.

All kinds of touch screens rely on sensors to work. Some touch screens themselves are even a set of sensors. Their respective positioning principles and the sensors used determine the response speed, reliability, stability and lifespan of the touch screen.

Performance

The resistive touch screen works in an environment that is completely isolated from the outside world. It is not afraid of dust, water vapor and oil, and can be touched with any object. It is suitable for use in industrial control. Is there any disadvantage? The outer layer of the composite film is made of plastic. Touching it too hard or using a sharp object may scratch it.

Capacitive touch screens have high resolution and good light transmittance. It well meets various requirements. This type of touch screen is commonly seen in public places. However, the capacitive touch screen uses the human body as an electrode of the capacitor.

When a conductor approaches and couples a large enough capacitance with the interlayer ITO working surface, the flowing current will cause the capacitive touch screen to malfunction. In addition, there will be no reaction when touched while wearing gloves or holding an insulating object. This is because the insulating medium is added.

Infrared touch screens determine the touch position by measuring the on-off of infrared rays, regardless of the material of the transparent baffle selected for the touch screen (some do not use any baffle at all). Therefore, choosing a baffle with good light transmittance and applying anti-reflective treatment can achieve good visual effects.

However, due to the limitation of the volume of the infrared emission tube, it is impossible to emit high-density infrared rays, so the resolution of this touch screen is not high. In addition, since the infrared touch screen relies on infrared sensing to work, changes in external light, such as sunlight or indoor lights, will affect its accuracy.

Surface acoustic wave technology is good, now. The controller calculates the touch position by measuring the position of the decay moment on the time axis, so its accuracy is very high. The surface acoustic wave touch screen also has a third axis (z-axis), which is the pressure axis-by calculating the attenuation of the received signal attenuation.

The force of the user's touch screen can be obtained. The greater the force, the wider and deeper the attenuation gap on the received signal waveform becomes. Among all touch screens, only this has the ability to sense touch pressure.

Development

Touch screen facilitates people's operation and use of computers. It's a promising interactive input technology. We invest a lot of manpower and material resources in research and development. Therefore, new types of touch screens are constantly emerging.

Touch pen

A touch screen operated by a touch pen is similar to the whiteboard. In addition to displaying interfaces, windows, and icons, the touch pen also has functions of signing and marking. The pen has greatly enhanced functions than the early light pen that only provided menu selection.

Touchpad

The touchpad uses pressure-sensitive capacitive touch technology. It has the largest screen area. It consists of three parts. The bottom layer is the center sensor, which is used to monitor whether the touch panel is touched and then process the information. The middle layer provides graphics and text for interaction. The outermost layer is the touch surface layer, which is made of very high intensity.

When a finger touches the outer surface, the information is sent to the sensor and logged in within a thousandth of a second. In addition to being compatible with PCs, it also has the characteristics of high brightness, clear images, and easy interaction. Therefore, it has been used in pointing information query systems (such as electronic bulletin boards).

In short, the development of touch screens shows trends such as specialization, multimedia, three-dimensionalization and large screen. People need to obtain a variety of public information. The public information transmission system with touch screen technology as the interactive window adopts advanced computer technology. It uses various forms such as text, images, music, explanations, animations and videos to introduce various information to people intuitively and vividly.