Regardless of whether it is a resistive touch screen or a capacitive touch screen, it is necessary to use transparent ITO glass or 1-D0 film with current passing through. ITO uses the rare metal indium. Because indium is facing the problem of exhaustion, people are actively developing conductive polymers or particles as substitutes for ITO materials. Coupled with increasing the recycling of indium, the problem of metal indium depletion has been temporarily alleviated.
The general structure of a resistive touch screen using a transparent conductive film. The top electrode of the resistive touch screen mostly uses a flexible film. In order to prevent input damage, a hard film layer (wet coating) must be used. With the expansion of the use of resistive touch screens, there are more and more corresponding hard film layers. The hard coat layer is divided into a clean type (Clear Type) and an anti-glare (AG) type. Products using the hard coat layer have the properties of good hardness, resistance to damage, high durability, anti-fingerprint, anti-glare (high-definition liquid crystal display), antibacterial properties for medical purposes, and good pen feel during input.
In addition, whether at the bottom electrode or the top electrode with a hard film, a hard film layer that prevents damage to the process and matches the adhesive layer is required.
In the resistive touch screen, because there is an air layer between the top electrode and the bottom electrode, it is easy to produce interference fringes such as Newton's rings. Improved measures can be adopted on the ITO side to prevent the generation of Newton's rings. The Newton ring is caused by the distance between the top electrode and the bottom electrode becoming very small, and the reflected light from the top electrode interface interferes with the original light after being reflected at the bottom electrode interface. The solution to this problem is to change the surface of the ITO surface. Carry out roughening treatment (that is, anti-Newton ring layer) to reduce the occurrence of interference.
In recent years, the application of resistive touch screens in the display of mobile products has increased a lot. In order to meet the requirements of mobile products for high-performance photo and video functions, liquid crystal displays are developing towards high-definition. The roughening of the anti-Newton ring layer and the anti-glare hard coating layer contradicts the high definition of the liquid crystal display without reducing the quality of the display screen of the touch screen. Therefore, it is necessary to strengthen the design of the roughness layer.
As a resistive touch screen, the market for netbooks, notebooks, and personal computers is gradually rising. For large-size applications, especially in terms of dimensional stability and surface smoothness, the requirements for transparent conductive films are very high. In the manufacturing process and use of touch screens, the flatness of the touch screen is particularly important.
In actual production, the material of transparent conductive film should be selected according to the different requirements of the product. The sensitivity of the top electrode input is very high. If the transparent conductive film is too thick, it will increase the load of the input; if the transparent conductive film is too thin, the operation will be slack and there is no elasticity, so a film with a thickness of about 0.2mm is generally used. Considering the lamination process and input action load, it is better to choose a thinner ITO film with a certain hardness.
