The mobile device industry is growing at an unprecedented pace. Not everyone managed to get used to the terms “candy bar, slider and clamshell”, as new ones appeared. For example, regardless of the wishes of users, manufacturers forcibly transfer everyone to touch screens, abandoning the hardware buttons. Now the choice of button devices, in comparison with sensors, is negligible. Good or bad - time will tell, but, most definitely, everyone should know what a touchscreen is.
This unusual term is a combination of two English words - “Touch” and “Screen”, which in literal translation can be read as “touch-sensitive screen”. Anyone who asks the question "touchscreen: what is it", simply does not always represent the scope of this technology. Residents of cities see touch-screen devices daily several times a day: bank boxes for receiving payments, information terminals, mobile phones, etc. When you click on certain sections of the screen, the fact of touching is recorded and processed according to the algorithms of the running program. Now on the Internet there is a lot of information about what a touchscreen is. In fact, the general principle of operation of such screens is quite simple and even a person who is far from electrical engineering can understand it. However, although the term is the same, the technology used for manufacturing determines the type of touch screen.
Surely, everyone who happened to choose a modern phone drew attention to the description of the variety of the touch screen - resistive or capacitive. Anyone who understands the question “what is a touchscreen” will easily choose the best model, because he understands the difference between them.
The basis of any touchscreen is a matrix on liquid crystals (in fact, a small copy located in the monitor). On the reverse side there are light-emitting diodes for illumination, and on the front surface there are layers that hold down pressure (resistive technology) and touch (capacitive type).
A person who has studied what a touchscreen is, no doubt knows that more than half of devices use resistive touch screens. This is due to the relative simplicity of their design and low cost. Most of the Chinese "smartphones" that flooded the market are made using resistive technology. In addition, importantly, this kind of screens appeared first.
The resistive type sensor is two transparent plastic plates with a thin mesh of conductive material, located on top of the liquid crystal screen. Between them is a dielectric layer (also transparent). Since the image on the matrix is clearly visible, the programs display a graphical interactive interface. The user, in response to a program request, clicks on a specific interface point (for example, the pictured button). As a result, the plastic dielectric diverges, and the plastic plates touch. The current supplied to the electrode of one of them enters the grid of the other. The recording controller picks up the appearance of current and determines the pressure point in accordance with the coordinate grid. Its coordinates are transferred to a working program and, in accordance with the laid down algorithms, are processed.
The consequences:
- a simple touch is not enough, you just need to press;
- due to the redistribution of the mass of the insulating layer over time, screen calibration is necessary;
- the number of clicks on each part of the screen is limited (from 3 to 35 million).
Otherwise, capacitive screens are arranged . In them, a transparent current-conducting coating is applied to the upper surface of the screen, with electrodes connected at the corners. When a person touches (large capacity) to such a layer, a leakage of current into the body occurs. The coordinates of the touch point are calculated and processed. Touch screens created using this technology can withstand over 200 million touches.