How Does Multi-Touch Screen Work

Definition of Multi-touch Screen

Multi-touch refers to a touchscreen interaction technique that the simultaneous multi-point or multi-user interactive operation can be achieved on the same display, which gets rid of the limitation of single-point and single-user operation modes such as keyboard and mouse. Users can perform single-touch and multi-touch with two hands and all fingers, and can also touch the screen with different gestures such as single-click, double-click, drag, press, scroll, and rotate to achieve navigation or to control objects, so as to better and more comprehensively understand the relevant characteristics of the object (Text, video, picture, 3D simulation information, etc.). Compared with single-touch, the main advantage of a multi-touch screen is that it can enhance the flexibility of screen operation and performance of human-computer interaction, enabling collaborative operation by multi-users and increasing user operation effectiveness and pleasure based on different usage scenarios


Work Mechanism of Multi-touch Screen

Multi-touch technology can be understood as decomposing the work of the touch screen into two steps, one is to collect multi-point input signals at the same time, and the other is to identify the meaning of each signal, so as to realize click and touch operation by multiple fingers on the screen at the same time.

At present, the main types of touch screens on the market, including capacitive screens, resistive screens, infrared screens, and surface acoustic wave screens, all support multi-touch. The realization mechanisms of the multi-touch functions of different touch screens are somewhat different.


Work Mechanism of Different Types of Multi-touch Screens

The multi-touch function of the infrared screen is realized by using the projection method to project infrared rays onto the screen. When the screen is blocked, the infrared rays will be reflected, and the camera under the screen will capture the reflection. After system analysis, it can make a response. It will add LED light to the interlayer of the screen. When the user presses the screen, the interlayer light will cause different reflection effects, and the sensor will receive the light change to capture the user’s press point.

The multi-touch function of the capacitive screen is realized by adding electrodes of mutual capacitance. Simply put, the screen is divided into blocks, and a group of mutual capacitance modules are set in each area to work independently, so the capacitive screen can detect the touch signals of each area respectively. Multi-touch is realized after simple processing. Capacitive touch screens are more sensitive and multi-touch capable, but they can also be affected by moisture, dirt, or gloves.

In the past, resistive touchscreens did not support multi-touch operation. With the technology development, this has become achievable. Resistive touchscreens can now be made to support multi-touch operation. Resistive touchscreens work by sensing pressure on the screen to detect touch commands. A Touch on the display surface will make the device’s top layer down onto the bottom layer within the area of your touch command. The resistive touchscreen will then respond by registering this area as a touch command. Multi-touch resistive touchscreens follow this same way by utilizing touch pressure to determine the locations where each of the touches occurred.

Surface acoustic wave (SAW) touchscreens support multi-touch operation too. They work by emitting ultrasonic waves over the surface of the display. Corresponding sensors are placed on the edges of the display interface to read and analyze these ultrasonic waves. When users touch the display interface, it will disrupt the ultrasonic waves in that area. Like resistive touchscreens, most SAW touchscreens designed in the past didn’t support multi-touch operation. Manufacturers have made efforts to introduce new technologies that allow SAW touchscreens to detect multiple simultaneous points of contact.


Applications of Multi-touch Screen

At present, there are many application fields of multi-touch screens, mainly including touch screens of personal consumer electronics digital products, commercial touch screens, industrial touch screens and touch screens used in educational scenes.

Among them, personal consumer digital products are characterized by small-sized and small amounts of concurrent touches, mostly two to five points, but they have higher requirements for control accuracy and are required to satisfy handwriting function and support rich application categories at the backend. In the application process, the single-person multi-point operation is widely seen among personal consumer digital products. The multi-touch technology of small-sized personal consumer digital products is developing in the direction of exquisiteness, and this type of application is very mature at present.

Commercial multi-touch touchscreen devices often have higher concurrency, but lower control precision requirements. Most of them do not require handwriting input functions, and their backend applications are relatively monotonous, focusing on applications of a certain type of content.

Compared with the traditional industrial touch display, the multi-touch display screen used in industrial scenes features higher flexibility and can perform data input and operation more conveniently. Because multi-touch technology allows users to use multiple fingers or gestures to achieve touch control, this technology can greatly improve the user’s interactive experience and work efficiency, and facilitate frequent data input and browsing by users. Multi-touch industrial displays can support a variety of data visualization methods like charts. They can support several people to operate at the same time, making collaboration more convenient and efficient. Multi-touch industrial displays can enhance device security by password setting and fingerprint recognition to protect sensitive data from being stolen or leaked. Multi-touch industrial PCs usually have an open system, which can support the integration of various software and applications to meet the needs of different industrial fields. This type of multi-touch display can be used in industrial automation, logistics management, production monitoring, medical care and other industrial fields. These devices usually feature higher dustproof, waterproof, impact-resistant and other performances to meet the requirements of harsh industrial environments.

Compared with the three application scenarios above, the education market application of multi-touch products is not very common and mature, only a few products support two-touch, and mainstream applications and relevant content have not yet been formed.


Market Trends

The multi-touch technology market is expected to register a CAGR of 13% during the forecast period 2021-2026. Smart terminals with touch screen like smartphones, tablets, and laptops have accounted for a major share of the multi-touch technology market. Increasing focus on multi-user displays, such as vertical screens and multi-touch tablets, is driving the growth of the market.

The multi-touch technology is a fragmented market with the presence of various global and regional players such as 3M, AD Metro Inc., DMC, Dongguan Genting Electronic Technology, Fujitsu, GestureTek, Ideum, Panasonic Corporation, Samsung Electronics, TouchNetix, etc. Most of these players are involved in several strategic developments, including mergers, acquisitions, new product development and launches, and market expansion, to gain a competitive advantage in the market.

In February 2018, Panasonic launched “ShadowSense”, a high-end multi-touch interactive display technology, to enhance its product offerings in the multi-touch technology market.

In January 2018, Cypress Semiconductor Corporation introduced a new automotive capacitive touchscreen controller, enabling advanced next-generation systems for infotainment applications. The technology is capable of detecting finger movement up to 35mm above the screen and features force touch functionality to provide accurate measurements of independent finger movement.


Top One Tech is a professional manufacturer of both single-touch and multi-touch touchscreens, touch monitors and touch computers, specializing in the customization of touch displays.

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