Introduction to capacitance and full fitting

-- TP process:

TP process generally refers to the composition process of capacitive touch sensor and protective cover plate. G+G, G+F, G+F+F structures are common. The "G" here means glass; F means foil. The manufacturing process of capacitive touch sensor includes: nano silver, ITO, Metalmesh, and printed copper wire.

1. G+G is to stick the glass cover G and the capacitive touch sensor made of glass together with glue. The capacitive sensor made of glass is generally ITO process, focusing on small size 55 inches and below, which has the advantage of high light transmittance, but also has the disadvantage of heavy glass; It is commonly used in tablet computers, learning machines, class cards and other scenes;

2. G+F/G+F+F is generally the glass cover plate G and the capacitive touch sensor made of the diaphragm state, which is a little light and low cost.

The single-layer process (printing TX/RX channels on both sides respectively) is G+F, and the double-layer process (printing TX and RX channels on two independent diaphragms respectively) is G+F+F.

--Manufacturing process of capacitive touch sensor:

Capacitive touch sensors are usually pasted on the back of the surface glass cover plate, between the glass and the LCD screen. The common ones are ITO process, nano silver process, Metalmesh process, and printing copper wire process

1. ITOsensor, vacuum sputtering process on glass, G+G process is used most. Its advantages are high light transmittance, but its disadvantages are relatively heavy. It is suitable for small size, generally between 10-55. It is used for plane computers and digital signs;

2. The wire diameter of nano silver process is generally 27 nm. It refers to the process of coating the PET film with silver paste and then laser etching the channel. The advantages are low cost, while the disadvantages are easy migration of silver ions, poor stability and low light transmittance. Honghe uses more nano silver on the market;

3. Metalmesh refers to the method of embossing grooves on the membrane material and filling silver paste. The wire diameter is 5-10um, which has the advantages of stable process performance, small square resistance, high signal-to-noise ratio, and high cost; It is widely used in the market by Seavo, Haikang and Skyworth;

4. The process of printing copper wire refers to printing micron sized S-shaped enameled wire on the film, with wire diameter of 15-19um. The advantages are the lowest cost, simple manufacturing process and the strongest signal; The disadvantage is that the line can be seen and is easily disturbed. At present, it is mainly used in outdoor advertising machines, object recognition and other fields with high requirements for signal strength;

--Fitting process:

The fitting here is different from the TP fitting, which belongs to the display process, and generally refers to the distance and combination mode between the surface protection glass and the LCD screen. It is irrelevant to touch technology, whether it is infrared or capacitance. Full fitting, zero fitting and frame pasting are common in the market.

1. Frame pasting: Frame pasting is the most common process in the market. The distance between the LCD screen and the surface cover plate glass is generally 5-10mm. The advantages are simple production and assembly, low threshold, and low cost; Disadvantages: poor clarity, poor visual angle, poor touch effect, easy to get dust and moisture; This is the practice for most digital signs on the market and low-end ordinary infrared touch control all-in-one machines;

2. 0 pasting: 0 pasting can be understood as a frame pasting technology with a closer distance between the LCD and the glass cover plate. Generally, there is a 1-2mm distance between the LCD screen and the surface cover plate glass. Compared with the frame pasting, the display is clearer and the visual angle is larger, but the electromagnetic interference is larger and the touch effect is not good;, The air and dust will still enter, which requires a large production environment and is difficult to produce; For example, most big brands in the market adopt this approach, such as Haikang, Dahua, etc;

3. Full fit: Full fit is the highest technology in the display field. Currently, all mobile phones on the market use full fit technology, which means that water glue or OCA glue is filled between the LCD screen and the glass cover. Advantages: no air refraction, clearer display, larger viewing angle, no air dust, consistent touch signal, better touch effect, but the disadvantages are long production cycle, complex manufacturing, and high cost. Large scale business display products are only used by some high-end products in the market, such as maxhub's V6 technology model, Honghe's high-end capacitive smart blackboard, H3C's all-in-one conference machine;