Most of the polarizers used for low-reflection touch screens are circular polarizers. A circular polarizer is attached to the surface of the touch screen through an adhesive layer. The polarizer is on the back side of the touch screen. It is called a film with a phase difference of 1/4 A, which can reduce the low reflection to less than 8 percent . The polarizer is mainly used in guides or cameras that need to shield external light.
In addition, the retardation film is also called a 1/4 A substrate, and is used for optically isotropic extension. The optical factor Re value is used as a basic characteristic, and it is mostly around 130 nm. Optical isotropy • The basic characteristics of 1/4 substrates are also Re. The difference between each company's products is whether the visible light is uniform throughout the range.
The role of Hardcoat Film is to prevent damage during operation. For example, it is often used in children's game consoles, because the surface of the game console screen is prone to wear, so it is necessary to increase the hardness of the surface film. Recently, a company introduced a touch screen with a surface hardness of 9H, which attracted much attention. Because the surface hardness of this touch screen reaches 9H, there is no need for lamination. Generally speaking, the hard film is rarely used alone in the touch screen, but is used together with the film with the following functions.
low reflection film can be divided into AR film and AG film. AR film is converted from the previous process of making lenses, and alternately laminating high refractive index layers and low refractive index layers to achieve low reflection. Generally, there are more two-layer (high refractive index layer/low refractive index layer) structures, and the four-layer structure low-reflection film can achieve a wider wavelength range than the two-layer structure low-reflection film. The main components of the low refractive index layer are SiO, SiO2 (refractive index around 1.45), etc.; the main components of the high refractive index layer are TiOx, ITO, ln203 (refractive index around 1.95), etc., and the film is made by sputtering process ,higher cost. The two-layer AR (low refractive index) film is mainly completed by a wet coating (Coating) process, and the cost is low. Recently, low refractive index films are more frequently used.
AG film is to roughen the surface of the electrode hard film on the top of the touch screen to scatter the reflected light to achieve the purpose of reducing reflection. The disadvantage is that it is not clear enough. It is said that most of the touch screens used in Japan are AG-treated touch screens, while those sold to other countries and regions are usually touch screens with a clear surface, which are very popular among consumers.
Some functions combined with tactile information prompts on the touch screen have also been introduced recently and put into practical use. Typical functions are to incorporate oscillators and error information feedback, etc. This is another application of optical film, which is realized by forming a concave-convex surface. In addition, some people propose to use a matte film in order to improve the feel.
The dirt on the display screen surface of the touch screen is clearly visible under the reflection of external light, which will directly affect the readability of the touch screen, so anti-fouling treatment is required. The basic principle of anti-fouling treatment is waterproof and oil-proof. Generally speaking, fluorine-based and silicon-based materials are coated on the surface of the material to reduce the surface energy and make it difficult for hydrophilic and lipophilic dirt to adhere to the surface. It is easy to wipe off stains using a fiber cloth with high surface tension to achieve the anti-fouling function.
