Large space spans, capacitive touch technology from single point to true multi-point quality change

Beijing time on April 28th news, China touch screen network news, it is still at least 10 years ago, black and white resistance screen "Wen Qu Xing" electronic dictionary is synonymous with the era of the tall, and before and after 08, but a few years, With the birth of the first generation of Iphone, the touch device seemed to have entered the home of ordinary people from Wang Xietang overnight. The Iphone series of smart phones is the earliest successful application of the most advanced capacitive touch technology at that time, causing a global sensation of touch products.

The most mainstream capacitive touch technology is divided into two types, surface capacitance and projected capacitance.

The surface capacitance is applied to the four corners of the ITO layer (conductive glass) of the screen to form a uniform, homogeneous electric field sensing layer. When the finger touches the screen, the sensing layer senses all positions on the screen, and the strength is weak. All the different electrostatic signals converge into a unified strong signal to identify the touch points. This recognition principle is simple but effective, and the development cost and difficulty are relatively low. However, due to the unification of all the identification signals on the screen, The surface capacitance is completely insulated from multi-touch in the underlying design principle and can only be applied in a single-touch environment.

Projected capacitors, also known as the Iphone series of mobile phones, and other capacitive touch technologies used in the most common and widely used smart touch devices in life. Compared with the four-corner voltage single-layer ITO electric field induction of the surface capacitance, the projected capacitive screen adopts multiple layers of ITO layers, which are distributed by X-axis and Y-axis to form a matrix-type capacitance distribution. When the finger touches the screen, it can pass X and Y. The scan of the axis detects the change in the capacitance of the touch position, and then calculates the position of the touch point, and then gives the touch point an exact X, Y coordinate orientation, some like the principle of GPS positioning.

The most significant advantage of this type of multi-layer matrix sensing through X and Y axes is that it is possible to identify multiple points. However, multi-touch is actually an extremely complicated technical problem. The earliest projected capacitive technology is only It is based on the principle of the underlying design to leave a door for the realization of multi-touch, and the distance between them is still real. The most obvious problem is that for the early projected capacitive technology, when the two touch points exist at the same time, the calculation program of the screen will have cognitive difficulties, and one point has two X and Y coordinate parameters. The two points correspond to four. At this time, the program will mix the four parameters together and cannot be correctly assigned to two points to determine the exact coordinates of the two points. That is to say, each point is identified and assigned X, Y parameters, only one of them is correct, and it is still impossible to determine which one is. If you want to judge, the correct rate is basically a coin toss. This phenomenon is Call it a ghost point. Due to the ghost phenomenon, the earliest multi-point projected capacitive touch is actually a pseudo-multiple point.

The clever thing about Iphone and other early touch smartphone designers is that although the ghost phenomenon hinders the accurate recognition of multiple points, in the case where the two X and Y coordinate parameters are only correct, you are not Know the exact position of the two points, but can calculate the distance between the two points and the approximate direction of motion, so there is a classic Iphone picture zooming and shrinking application, many people have seen this feature of the artifact is also surprised by technology It has been developed to this point. In fact, Iphone is just a clever way to change the size of the image by calculating the distance between two fingers. Whether you are pulling horizontally, vertically or diagonally, the zooming action of the image itself is the same. of.

Nano-touch is an improved projected capacitive touch technology. The ProTouch ifoil series of nano-touch produced by the company is an example. The nano-wire sensing film is used to replace the ITO layer of the traditional capacitive screen. It has also made a completely different improvement. Its appearance is a thin, transparent film with a circuit board at the end. When used, the touch film is attached to the glass, connected to the host with a USB cable, and touched by a touch glass. This has brought three significant breakthroughs.

The first is the breakthrough in size. The nano-sensing film does not have the size limitation of the ITO layer on the material. It can easily break the "32" limit capacitor cage that has been developed for many years. The maximum size can be 180 inches. You have seen 180 inches. Iphone? In theory, it can really be done now.

Another major breakthrough is in the recognition of true multi-touch. The real application of large-size touch screens is mainly in the fields of media display, public service, entertainment, etc. The form of display is basically fixed touch screen, such as touch screens of shopping malls, touch advertising machines, and touches of fashionable restaurants. Control the table and so on. As a result, large-size fixed touch devices in many application environments need to meet the application requirements of multiple people simultaneously interacting, that is, it is necessary to recognize multiple points. Thanks to the significant improvement of the algorithm, nano-touch realizes the recognition of true multi-touch. The latest multi-touch nano-touch film Protouch iFoil V10 launched by Pan-Pu Nano can accurately identify up to 20 touch points. Each point can recognize independent and accurate X and Y coordinates, and there is no ghost point phenomenon. With a size range of 30 to 100 inches, it can meet the application requirements of most large-size, multi-person interactive environments.

The third breakthrough is in waterproof performance. It is also due to the replacement of the ITO layer by the nano-sensing film, which makes the sensing element have waterproof performance. In practical applications, it can be widely used in outdoor, catering, home, etc. An area that is beyond the reach of the problem.

The development of touch technology has been continually moving toward a wider range of sizes, a smoother touch experience, more accurate and large number of point recognition, more powerful environmental adaptability and a more aesthetically pleasing design. Panpu is willing to work with partners to make human life more beautiful and intelligent.

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