Touch screen, from the market concept, is a computer input device that everyone can use, or a device that everyone can use to communicate with the computer. Everyone can use it. It’s the biggest magic of touch screen, which can’t be compared with keyboard or mouse. Everyone can use it, which marks the true arrival of the era of computer application popularization.
In terms of technical principle, touch screen is a transparent absolute positioning system. First of all, it must be transparent, so it must solve the problem of transparency through material technology. For example, digitizer, tablet and elevator switch are not touch screens; Second, it is the absolute coordinates, where the fingers touch, no second action, unlike the mouse, is a set of relative positioning system.
Touch screen has three basic features: 1. Transparency. It directly affects the visual effect of the touch screen. Transparency is only a general concept in the touch screen industry. Many touch screens are multi-layer composite films. It is not enough to summarize their visual effects only with transparency. It should at least include four characteristics: transparency, color distortion, reflectance and clarity. For example, reflectance includes specular reflectance and diffractive reflectance, However, the diffractive reflection on the surface of our touch screen has not reached the level of a CD. For users, these four features are basically enough.
2. Absolute coordinate system. Touch screen is an absolute coordinate system, which can be directly selected. The essential difference between touch screen and relative positioning system such as mouse is the intuitive one-time positioning. The characteristic of absolute coordinate system is that each positioning coordinate has nothing to do with the last positioning coordinate. The touch screen is a set of independent coordinate positioning system physically. The data of each touch is converted into the coordinates on the screen through calibration. In this way, the output data of the same point of the touch screen is required to be stable no matter what the situation is, So the touch screen can’t guarantee the absolute coordinate positioning, and the point is not accurate. This is the problem that the touch screen is most afraid of: drift. In technical principle, any touch screen that can’t guarantee the same touch point and the same sampling data can’t avoid the problem of drift.
3. Detect touch and locate. All kinds of touch screen technology rely on their own sensors to work, and even some touch screen itself is a set of sensors. The response speed, reliability, stability and service life of touch screen are determined by their respective positioning principles and sensors. The sensor mode of the touch screen also determines how the touch screen can recognize multi touch, that is, how to touch more than one point at the same time? When someone touches it, what if someone touches it next to it? This is a common problem in the use of touch screen, but there is no ideal solution at present.