In the future, the touch screen mobile phone should be a large screen with good slim figure, and the user only needs to operate it with one hand. IPhone shows people an unprecedented brand-new mobile phone operation experience, such as no stylus, no buttons and multi-touch. Almost at the same time, the industry has brought TouchFlo technology which is ahead of the industry, thus giving people a new understanding of WindowsMobile operating system-it adapts to the development of touch technology, constantly enhances the user experience and facilitates the operation of mobile phones. More interestingly, with the popularity of touch screen technology in the past two years, many so-called "cottage phones" have also incorporated touch functions into mobile phones within 1, yuan. The evolution of mobile phone screen is rapid. First, the color of mobile phone screen changes from black and white to color, from 256 colors to millions of colors, and finally to full-screen large-size multi-touch now. Mobile phone manufacturers are constantly updating the hardware characteristics of mobile phone screen. The reason for this is simple: the only human-computer interaction tool when people use mobile phones is the screen, which is indispensable for making phone calls, sending text messages, or conducting business and entertainment functions. Therefore, to simplify the user's operation process directly, it is natural to think of making the mobile phone screen operable at the same time, not just for display. The evolution of mobile phone screen is very rapid. Let's take Motorola, which was once a leader in handwriting input, as an example. In 1999, Motorola launched the world's first Chinese handwritten touch-screen mobile phone A6188, which subverted the traditional mobile phone numeric keyboard input method at that time, leaving the text input part of the mobile phone to the touch screen and stylus to solve. This alone was enough to attract consumers' attention and became the best choice for countless high-end users at that time. However, it seems that at that time, people simply equated the function of the touch-screen mobile phone with handwriting input, ignoring that the touch function can actually penetrate into the various functions of the mobile phone itself, and improve the overall operating efficiency and visual experience of the mobile phone. As a result, with the passage of time, touch-screen mobile phones that don't mainly use handwriting function have appeared in the market. For example, Motorola's E68 and E6 promote touch-screen phones with the theme of games and entertainment respectively, and Microsoft gradually downplays non-touch-screen phones, giving priority to improving the user experience of touch screens, and strengthening and highlighting the convenience brought by touch screens to users. But all this was interrupted by the shocking listing of the iPhone. IPhone completely subverts the experience of using the touch screen, making everyone understand that a mobile phone can complete complex operations that can only be completed through cumbersome menus simply through finger touch or multi-touch. IPhone also emphasizes the seamless combination of software and hardware. At the beginning of OS (operating system) design, it takes into account the influence of touch on program operation, and at the same time pays special attention to details such as UI (man-machine interface), program design and button style, all of which embody the purpose of fundamentally solving the basic experience of human-computer interaction. Its appearance has led to the rapid extension of the whole touch screen technology and the reform of related software industries. Handwriting is not equal to touch screen. What kind of high-tech product is a touch screen? Let's start with the hardware types of touch screens. At present, ordinary touch-screen mobile phones on the market (such as Motorola, Sony Ericsson, Samsung, dopod and other brands) usually use resistive touch screens. This kind of touch screen is controlled by pressure sensing, and its main component is a resistive multilayer composite film screen that matches the surface of the display screen very well. When a finger or stylus clicks on the touch screen, the two conductive layers produce a contact point at the touch point, and at this time, the resistance changes, generating signals in the X and Y axes, and then sending them to the touch screen controller. The controller detects this contact point and calculates the accurate position, and then operates according to the way of simulating a mouse, which translates into different specific operation effects. This is the most basic principle of resistive touch screen. Simply put, the touch screen is equivalent to an input sensing device, which can directly input or operate the device instead of a mouse or keyboard. Because the operation of the touch screen is completely what you see is what you get, it is an absolute positioning process. As long as you touch the menu or button of the function that the user wants to realize on the screen, the effect can be presented immediately, and it is not necessary to transform it through the operation of the hardware buttons (navigation keys, function keys, etc.) on the mobile phone, which not only saves the manufacturing and design costs of the hardware buttons of the mobile phone, but also saves valuable design space for the mobile phone screen. At present, resistive touch screen technology is very mature, and the production cost is reduced after mass production. It has been used as the basic configuration of mobile phones by most mobile phone manufacturers and even "cottage" manufacturers, and is widely used in their new products. However, the technology of resistive touch screen is limited to single touch in function, and because there is no hard material to protect the front of resistive touch screen, it is easy to cause screen damage in the daily use of users. Therefore, in order to make a new breakthrough in touch screen, innovation is still needed. As a result, new technologies came into being. Capacitive touch screen solves the biggest problem of resistive touch screen-the use of high-hardness touch screen, which makes capacitive touch screen have a gorgeous appearance and a hard shell, which greatly promotes the development of touch screen technology. At the same time, because of its unique design principle, the unique function of multi-touch has never been possible. From the structure of this kind of touch screen, it is mainly to coat a transparent thin film layer on the glass screen, then add a protective glass layer outside the conductor layer, and then lay long electrodes on the four sides of the touch screen, which form a low-voltage AC electric field in the conductor. After people touch the screen with their hands, the current from the four electrodes will accurately measure the position of the touch point in a way of crossing ten times. This design also guarantees the durability of the product itself. Generally speaking, capacitive touch screens can have enough space to add a piece of protective glass, which can completely avoid the water ripple phenomenon that is easy to occur on resistive touch screens during use, and better ensure the screen display effect of the touch screen. Based on the touch principle of capacitive touch screen, multi-touch operation has become the latest technological highlight. In principle, the resistive touch screen can only accept one touch point at a time. If the number of touch points increases, the system will not be able to correctly judge the position of this touch point, thus failing to respond correctly. However, the principle of capacitive touch is different. The display screen can accept the analysis and judgment of two or more contact points, so as to complete more complicated program operations, such as two fingers simultaneously enlarging or reducing the picture, browsing the webpage, and zooming in at any time. It is no longer difficult to access the Internet by using a mobile phone. Multi-touch is the development direction. The success of iPhone benefits from the perfect combination of software and hardware, and also benefits from the OS architecture tailored for touch technology. Based on this design, users can input text without using hardware keyboard at all, which reduces the wear of hardware keys, and manufacturers also save design space, leaving space for large-size display screen to improve the display effect. Good touch screen programming can make users abandon the stylus completely, which can not only save the stylus as an accessory, but also solve the headache of not being able to operate it with one hand in some special occasions. The author boldly believes that the future touch-screen mobile phones should be developed in the direction that the hardware is a large screen, with a good slim figure, and the user only needs to operate with one hand. The latest report published by IMSResearch, a market research company, predicts that although the global sales of touch-screen mobile phones were less than 3 million last year, the sales of touch-screen mobile phones will exceed 23 million by 212. Because the emergence of iPhone has brought all mobile phone manufacturers an unprecedented sense of crisis, which is the driving force for more touch-screen mobile phones to go on sale. Nokia has announced that it will shift its focus to the development of touch-screen mobile phones, which will be fully rolled out in the future product line. Microsoft will implement multi-touch in WindowsMobile7 next year, fully keeping up with the development trend of touch screen. In order to make up for the inherent shortcomings of their respective operating systems, manufacturers try their best to optimize the touch function and one-handed operation performance. For example, the mobile phone uses TouchFlo technology to optimize the system, completely getting rid of the original scroll bar to scroll items. As long as the finger presses the screen and slides up and down, the item can be located and selected, and it can simulate inertia sliding, and then slowly stop, completely simulating the current operating experience on the computer. These innovative experiences are called touch screen gesture recognition, and they are also widely used in the process of browsing pictures and web pages. I believe that in the future, due to the continuous development of touch screen technology, the corresponding software operation will be more humanized and bring users a better operating experience. Related links The technical principles of various touch screens are introduced. Resistive touch screens can only judge one touch point at a time when working. If there are more than two touch points, they cannot make correct judgments, so resistive touch screens are only suitable for judging simple actions such as clicking and dragging. The multi-touch of capacitive touch screen can decompose the user's touch into two tasks: collecting multi-point signals and judging the meaning of signals, and complete the judgment of complex actions. The surface touched by the fingers of the resistive touch screen is a hard coating to protect the PET (Polyester Film) layer below. There are two transparent conductive layers ITO (Indium Oxide, weak conductor) between the surface protection hard coating and the glass bottom layer, which correspond to the X and Y axes respectively, and they are insulated by fine transparent insulating particles. The pressure generated by touch will make the two conductive layers connected. When different points are pressed, the resistance value from the point to the output end is different, so the output will be different from that point. This is the most basic principle of resistive touch screen. Capacitive single-point touch screen Single-point capacitive touch screen only uses a single layer of ITO. When the finger touches the surface of the touch screen, a certain amount of charge will be transferred to the human body. In order to recover these charge losses, charges are added from the four corners of the screen, and the amount of charges added in all directions is proportional to the distance of the touch point, from which we can calculate the position of the touch point. Capacitive touch screen can only judge one touch point at a time. If more than two points are touched at the same time, it will not be able to make a correct response, or the response will be confused. The task of multi-touch of multi-touch capacitive touch screen can be divided into two aspects: one is to collect multi-touch signals at the same time, and the other is to judge the meaning of each signal, which is called gesture recognition. Compared with touch technology, which can only accept single input, multi-touch technology allows users to touch the display screen in multiple places at the same time, so as to be able to expand and rotate web pages or pictures. Apple iPhone only allows two fingers to operate, so it can be called "double touch", while Microsoft's upcoming Surface computer can respond to 52 touch points at the same time. In order to realize multi-touch function, multi-touch screen and single-touch screen adopt completely different structures. From the outside of the screen, a single touch screen has only a few signal lines (generally 4Pin or 5Pin), while a multi-touch screen has many leads. From the inside, the conductive layer of a single-point touch screen is just a flat plate, while a multi-touch screen is divided into many relatively independent touch units on the flat plate, each touch unit is connected to an external circuit through an independent lead, and all touch units are arranged in a matrix on the board. In this way, when a user's finger touches a certain part on the screen, a signal will be output from the corresponding detection line. When the finger moves to another part, it will output signals from another detection line. Apple applied for two patents of multi-touch panel for iPhone-self capacitance and mutual capacitance. From the use point of view, there is no essential difference between the self-capacitive touch screen and the mutual-capacitive touch screen, but the difference is their internal structure-the mutual-capacitive touch screen has isolated drive lines and detection lines, while the self-capacitive touch screen has only one layer of transparent electrodes. There are 19 lines on the board of Go horizontally and vertically, which can hold up to 19×19=361 pieces. Similarly, the criss-crossing detection lines on the multi-touch screen have many intersections, and each intersection can be regarded as a touch point. From the perspective of touch screen, it can really support a lot of touch points. How many touch points can actually be supported is ultimately determined by DSP chips and software. The development trend of capacitive multi-touch screen Capacitive multi-touch screen has been applied to iPhone and other handheld devices. Positioning single-point trajectory/simulating mouse double-click is its basic function, and the recognition and application of multi-finger gesture operation has become a hot spot in the current market. In portable applications, users can only operate the device with one hand, so it is particularly important to recognize gestures such as grabbing/translating, stretching/compressing, rotating and turning pages with multiple fingers. In the past, due to factors such as cost and technology, resistive control panels were used far more than capacitive touch technology. However, in the recent stage, with the progress of technology and batch production, the price of capacitive touch screen is declining, and the price gap with resistive touch screen is getting smaller and smaller, and it gradually has the ability to compete with resistive touch screen in price. Multi-touch technology will gradually replace the traditional single-touch technology with the maturity of the market and the reduction of cost, as well as its unique selling point, comprehensive function and stability.