In everyone’s daily life, there are a lot of touch-enabled electronic devices. For example, many cash machines in banks have touch functions, and many hospitals, libraries, etc. have computers with touch technology installed in the lobby. There are also many mobile phones, MP4, and digital cameras that support touch screens. However, these touch screens are all single-point touches, which can only recognize and support one finger touch and click at a time. If more than two points are touched at the same time, the touch screen cannot respond.

The multi-touch technology (Multi-Touch) can decompose the task into two aspects of work, one is to collect multi-point signals at the same time, and the other is to judge the meaning of each signal, which is the so-called gesture recognition, so as to realize the function that the screen recognizes the click and touch actions made by the five fingers of a person at the same time. It belongs to the field of human-computer interaction, and its appearance is to satisfy people's desire for more and more convenient and simple operation of electronic devices.

What is multi-touch technology?

As the name suggests, it recognizes the touch of two or more fingers. There are currently two multi-touch technologies: Multi-Touch Gesture and Multi-Touch All-Point.

Multi-Touch Gesture

What we see most now is Multi-Touch Gesture, that is, when two fingers touch, the direction of movement of the two fingers can be recognized, but the specific position cannot be located yet, and operations such as zooming, translation, and rotation can be performed. This kind of multi-touch implementation is relatively simple, and it can be implemented by means of axis coordinates.

Dividing ITO into X and Y axes, two touch operations can be sensed, but sensing the touch and detecting the specific position of the touch are two concepts. The Y-axis touch screen can detect the second touch, but cannot know the exact location of the second touch. A single touch produces a single maximum value on each axis to determine the location of the touch. If a second finger touches the screen, there will be two maximum values on each axis. These two maximum values can be generated by two different sets of touches, so the system cannot accurately judge. Some systems introduce timing to make judgments. It is assumed that two fingers are not put on at the same time, but there are always situations where they are touched at the same time. At this time, the system cannot guess either.

Multi-Touch All-Point

Multi-Touch All-Point can identify the specific location of the touchpoint. Multi-touch recognition position can be applied to the detection of any touch gesture. It can detect the simultaneous touch of ten fingers of both hands. It also allows other non-finger touch forms, such as palms, faces, fists, etc., even wearing gloves. It is the most user-friendly man-machine interface and is very suitable for applications with multiple simultaneous operations, such as game control. The scanning method of Multi-Touch All-Point is that the intersection of each row and each column needs to be scanned separately, and the number of scans is the product of the number of rows and the number of columns. For example, touch screen composed of 10-row lines and 15 column lines, using the axis coordinate method of Multi-Touch Gesture, needs to scan 25 times, while the multi-touch recognition position method requires 150 times.

How is multi-touch achieved?

Multi-touch technology can be realized, this is because the human body itself has a high induced voltage, which will bring clutter interference or capacitive effect.

The multi-touch technology uses this to integrate the touch chip into the electronic device (touch display, touch all-in-one computer), and uses the human body’s capacitive effect, that is, the human body’s approach will increase the capacitance, thereby changing the original oscillation frequency or changing the charging and discharging time of the RC circuit.

The working principle of the touch chip is similar to that of the AD chip. It mainly converts the collected analog signal into a digital signal and runs it in the device. The core component of multi-touch technology is the touch IC. Most touch chips are designed based on LLP technology, FTIR technology, ToughtLight technology, and Optical Touch technology.

Multi-touch technology not only drives the development of the entire smartphone industry today but also drives the development of a new generation of tablet computers, portable notebook computers, and various electronic devices. The electronic market is so hot now that it is inseparable from the emergence and application of this technology. It can even be said that this technology is the main driving force behind the hot market. Under the application of this technology, Top One Tech will continue to develop more interactive methods that conform to user habits based on it, and human-computer interaction will become more and more natural and seamless.