The
Touch Screen is not new. Long before the arrival of this wave of smart phones, you have seen touch screens on various handheld computers, mobile phones, and even black and white screen mobile phones. But in most people's impressions, the touch screen of that era always appeared with the touch pen—you have to press the hard object of the pen or nail to achieve the input command, which is essentially a “
Resistive Touch Screen”. . Until the emergence of the iPhone in 2007, another touch screen, "
Capacitive Touch Screen" began to appear in people's sight. However, after 4-5 years of development, the touch-type intelligent terminal market has already turned into a capacitive touch screen from a resistive touch screen.
Resistive touch screen
The conventional resistive touch screen has a total of five layers. The surface touched by the finger is a hard coating to protect the underlying PE T layer (a protective material with good transparency and gas barrier properties). The PET layer is a very thin, flexible PE T film that bends down when the surface is touched and causes the underlying two layers of IT O coating (a nano-indium tin metal oxide that has good electrical conductivity and Transparency) is in contact with each other and is connected to the circuit at this point.
Advantages: The technology is mature, the cost is relatively low, and the surface is not susceptible to dust, water and dirt.
Disadvantages: The IT O coating in the touch screen is thin and brittle. If it is too thick, it will reduce the light transmission and form internal reflection to reduce the sharpness. The life of such a touch screen is not long, and it is necessary to frequently perform position correction of touch points.
Capacitive touch screen
Capacitive touch screens are divided into "Surface CapaciTIve Technology" and "Projected CapaciTIve Technology".
The “surface capacitive touch screen” uses only a single layer of IT O. The electrodes are plated with narrow electrodes on all four sides of the touch screen to form a low voltage AC electric field in the conductor. Compared with the resistive type, the biggest feature of the capacitive type is that it does not need to be pressed, and only needs to be touched to input an instruction.
As for the "projected capacitive touch screen", it can penetrate a thicker cover layer and does not require correction. Projection capacitors can be used for the iPhone's iconic "multi-touch" operation.
Advantages: only touch, no pressure is required to generate the signal; only one or no correction is required after production; the life will be longer because the components in the capacitive touch screen do not require any movement.
Disadvantages: The cost is relatively high, but with the current mainstream smartphones choosing a capacitive screen, the scale is exploding and the cost is decreasing.
