Mobile phone protective film | mobile phone protective film thin thickness
There are two types of film thickness measurement: online testing and off-line testing. The first one used for film thickness measurement is the off-line thickness measurement technology. After that, with the continuous development of ray technology, an online thickness measurement equipment installed with the film production line was gradually developed. Online thickness measurement technology has been widely used in the 1960s, and now it is more able to detect the thickness of a certain coating on a thin film. On-line thickness measurement technology and off-line thickness measurement technology are completely different in the testing principle. On-line thickness measurement technology generally uses non-contact measurement methods such as ray technology, while non-online thickness measurement technology generally uses mechanical measurement methods or is based on eddy current technology or electromagnetic induction. Principle measurement methods also use optical thickness measurement technology and ultrasonic thickness measurement technology. The thickness measurement of the protective film for thin mobile phones is one of the basic testing items in the film manufacturing industry. Some other performance indicators of the film are related to the thickness. Obviously, if the thickness of a batch of single-layer films is uneven, it will not only affect the tensile strength and barrier properties of the film, but also affect the subsequent processing of the film. For composite films, the uniformity of thickness is more important. Only when the overall thickness is uniform can the thickness of each layer of resin be uniform. Therefore, whether the film thickness is uniform, whether it is consistent with the preset value, whether the thickness deviation is within the specified range, these all become the premise of whether the film can have certain characteristics. The more common online thickness measurement technologies include β-ray technology, X-ray technology and near-infrared technology. 1 β-ray technology β-ray technology is the first ray technology applied to online thickness measurement technology, and has been widely used in online thickness measurement of ultra-thin films in the 1960s. It has no requirements for the measured object, but the beta sensor is sensitive to changes in temperature and atmospheric pressure, and the fluctuation of the film. The equipment has high requirements for radiation protection devices, and the signal source is expensive to replace. The Pm147 source can be used for 5-6 years, and the Kr85 source can be used. In 10 years, the replacement cost is about 6000 US dollars.