The touch screen can be mass-produced with less investment. The materials used in touch screens are mostly the same as those of liquid crystal display panels, but the manufacturing method is different. In the cost of touch screens, material costs account for the highest proportion. The main materials of the resistive touch screen are the upper film substrate with ITO, the lower glass substrate with ITO, FPC for connecting circuit signals, silver glue, spacers and so on.
The thickness of ITO glass is generally 1.lmni or 0.7mn^ The touch screen ITO is the same as the IT0 used in the liquid crystal display panel, but the manufacturing method of the IT0 is different. To make IT0 of the LCD panel, the resistance value should be as low as possible. The sheet resistance is generally about 10~200/□ (corresponding film thickness is about 1000~1500A).
In contrast, IT0 for touch screens requires a high resistance value, the sheet resistance is generally 50011/□, and the corresponding film thickness is 200 to 400A. The uniformity of touch screen products is very important. There can be no too much fluctuation in a substrate, which is mainly determined by the IT0 film. In addition, when the touch screen realizes the touch function, it is necessary to contact the upper and lower substrates to make them conductive, and then separate them to return to the non-conductive state. Therefore, the surface of the IT0 should preferably be uneven. Because of this performance requirement, the technology used to make touch screens is more difficult than LCD panels. Although the manufacturing method of the ITO film is the same, in order to prevent or reduce the generation of Newton’s rings, an anti-Newton’s ring layer is provided between the film substrate and the ITO film. In addition, in the ITO coating process, a low-temperature coating process that is lower than the melting temperature of the substrate must be used.
Due to the above-mentioned technical barriers, there are not many IT0 substrate manufacturers that produce touch screens. In the touch screen, the material cost, especially the IT0 substrate cost is higher. The cost of the two substrates accounts for about half of the total price of touch screen products. Coupled with the cost of FPC and other materials, it exceeds more than half of the total product price.
As mentioned above, as the main manufacturers of touch screens move from Japan to China, South Korea, etc., the suppliers of main raw materials and parts are gradually increasing in the same area. Coupled with the continuous improvement of the production technology level, the cost of making touch screens It is also declining continuously.
