Analysis of the three major touch screen technologies

For electronic products, especially consumer products, how to transform users' complex control actions into intuitive, convenient and productive experiences is the ultimate challenge facing user interface design. Let's learn about the relevant content with the mobile phone portable editor.

User interface design must consider the needs of the user's five senses, namely vision, hearing, taste, smell and touch, on the one hand, and the impact of user needs on the device or system on the other hand. Most of the products currently on the market, although effective, mainly treat the user's vision and touch separately. From simple buttons or keys on computer keyboards, mobile phone keyboards, MP3 players, home appliances and even TV remote controls, to more advanced click and scroll features on volume sliders, scroll wheels and track pads [LU1], the output location (that is, the result of the user's input or manipulation action [LU2]) is completely different from the user's input location. How great it would be if the input and output, that is, vision and touch, could be completely consistent! And this consistency of vision and touch is the basic advantage of touch screens.

It is easy to say that making vision and touch completely consistent, but it is a far-reaching technological breakthrough that will completely change the way users interact with electronic products. Some people call it a revolution in user interfaces. The transparent nature of touch screens allows users to directly "touch" different contents on the display screen, which makes people sigh at such user interface design. Because users no longer have to find this or that button around the electronic device, such as a computer mouse or keyboard or even the dial button on a mobile phone, but directly interact with the application solidified in the device's "brain" (that is, its operating system). This is a revolutionary change. This control method allows users to directly control powerful operating systems and applications, all at the user's fingertips. Of course, we can use mice and tracking [LU3] pads on computer screens to access applications, but this control is not directly touching the display screen, and it cannot allow users to integrate with the screen and embedded applications. In fact, we can use touch screens through various actions or gestures that we can imagine, making the display screen vivid and vivid, as long as the eyes can see, we can simply interact with it through touch. At present, touch screens are mainly divided into three categories: single-point touch; multi-point touch to recognize finger direction; multi-point touch to recognize finger position.

Single touch screen

Touchscreens have evolved from simple to complex, with the earliest products supporting only the simplest control, which is to touch a point on the screen with a finger. For example, we do this every day at the POS terminal in the supermarket or the check-in terminal at the airport. Previously, we could only control it through mechanical buttons around the screen. Single-touch screens have made great progress in user interface. Of course, mechanical and new capacitive touch-sensing buttons are ubiquitous in our homes, offices and other places: mobile phones, landlines, remote controls, televisions, computers and their various peripherals, game consoles, refrigerators, microwave ovens, ovens, and in-car electronic control devices such as radios and air conditioners. Now, single-touch screens, such as the one shown in Figure 1 below, integrate the user control interface directly on the display, so the traditional mechanical buttons are no longer needed.

Figure 1 Single-point touch screen function

This screen brings two major benefits to the user interface. First, the device design space is optimized, which is particularly beneficial for small devices because the screen and buttons can be "installed" in the same area at the same time; second, because the buttons can be bound to any application in the operating system, the device can use an unlimited number of "buttons". The above functions are mainly based on resistive touch screen technology and have been widely promoted in various applications such as consumer electronics, airport newsstands, grocery store POS terminals and car GPS systems.

Multi-touch screen - identifying finger direction

Although single-touch and resistive touchscreen technology is surprising and revolutionary, it has two major drawbacks. First, resistive technology relies on the physical movement of the touchscreen [LU5], which, although not a big deal [LU6], will degrade after normal wear and tear. Second, this technology only supports single-touch, which means that only one finger can be used to perform a single action on a certain area of ​​the screen at a time. Why should users' interaction with devices be limited to one finger? Apple has made an immeasurable contribution to the user interface revolution with its iPhone, which uses an inductive capacitive touchscreen. Even in small devices such as smartphones, multiple fingers are required to achieve optimal usability in order to fully utilize the functions of applications and operating systems. Because of Apple, it is now difficult for users to imagine how they could have completed operations such as zooming in and out of photos and changing the orientation of albums and web page views in the past without supporting two-finger gestures.

Figure 2 Image zooming on a multi-point gesture touch screen

Other technology innovators are continuing to use multi-touch technology in a variety of device systems, including the Google G-1 and Blackberry Storm smartphones, MacBook Pro and HP touchsmart desktop and notebook computers, portable media players, and many other applications. Now, users have new expectations and hope to further improve the way users interact with their electronic products, and various electronic products are also scrambling to meet users' new demands.

Multi-touch screen - identifying finger positions

Like single-point touch screens, multi-point touch screens that recognize finger directions also have a limitation in that the technology can recognize a limited number of operating points on the screen at the same time. Why can only two operating points be recognized at a time? The user has ten fingers on both hands, and when users interact with each other, more fingers appear on the screen. This is where the concept of multi-point touch, which recognizes finger positions, comes in, and it can achieve control with more than two fingers.

Cypress calls this technology "Multi-Touch Full-Area Input," and it further improves the usability of touch screens to meet the needs of a variety of feature-rich applications. Reliability refers to our ability to accurately capture the raw data of all touch points on the screen with the highest granularity, minimizing the confusion caused by inaccurate positioning of screen touch points. Usability refers to the ability of many powerful applications to benefit from the ability to control the screen with two hands or more than two fingers on screens of different sizes. 3D interactive games, keyboard input, and map operation are some of the main targets that use this touch screen function.

Fundamentally, multi-touch full-area input technology provides device and system OEMs with all touch data at their fingertips, helping them to be creative in developing the next generation of new and useful technologies.

Multi-touch screen that can detect finger positions

The TrueTouch touch screen solution launched by Cypress Semiconductor is an application example of multi-touch full-area input. TrueTouch uses the Cypress PSoC programmable system-on-chip architecture, which integrates an 8-bit microcontroller with programmable analog and digital blocks. It can achieve unparalleled flexibility and configurability. The inductive capacitive touch screen controller of the TrueTouch solution can be expanded to support screens of various sizes, and can flexibly support single-point touch, multi-point touch that recognizes the direction of the finger, and multi-point touch technology that recognizes the position of the finger. TrueTouch can highly integrate external components and is particularly suitable for working with various touch screen sensors or LCD displays. The flexible PSoC architecture enables designers to easily make modifications in the final stage of product design, which is impossible for other touch screen products.

The above is an introduction to the analysis of the three major mainstream touch screen technologies in portable mobile phones. If you want to know more related information, please pay more attention to eeworld. eeworld Electronic Engineering will provide you with more complete, detailed and updated information.