Touch screens can be mass-produced with less investment. Most of the materials used in the touch screen are the same as the LCD panel materials, but the production methods are different. In the cost of touch screens, the proportion of material costs is the highest. The main materials of resistive touch screens are upper film substrate with ITO, lower glass substrate with ITO, FPC connecting circuit signals, silver glue, septum cushions, etc.
The thickness of ITO glass is generally 1. lmni or 0. 7mn^ touch screen ITO is the same as IT0 for LCD display panels, but the production method of IT0 is different. To make the IT0 of the LCD display panel, the resistance value should be as low as possible, and the square resistance is generally about 10?200/□ (the corresponding film thickness is about 1000?1500A).
In contrast, IT0 for touch screens requires high resistance values, and the block resistance is generally 50011/□, corresponding to a film thickness of 200?400A. The uniformity of touch screen products is very important, and there should not be too much fluctuation within 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 conduct, and then separate them to return to the non-conductive state, so the surface of IT0 is best to have some bumps. Because of this performance requirement, the technology used to make the touch screen is more difficult than the liquid crystal display panel. Although the IT0 film production method is the same, in order to prevent or reduce the generation of Newton rings, an anti-Newton ring layer is provided between the film substrate and the IT0 film. In addition, a low-temperature coating process with a lower melting temperature than the substrate must be used in the IT0 coating process.
Due to the above technical barriers, there are not many IT0 substrate manufacturers that produce touch screens. In the touch screen, the cost of materials, especially IT0 substrates, is high. The cost of two substrates accounts for about half of the total price of the touch screen product. Combined with FPC and other material costs, it accounts for more than half of the total price of the product.
As mentioned earlier, as the main manufacturers of touch screens shift from Japan to China, South Korea, etc., the number of manufacturers supplying major raw materials and parts in the same region is gradually increasing, coupled with the continuous improvement of production technology, the cost of making touch screens is also declining.