After the optical lens is finely ground by the abrasive liquid, there is still a crack layer about 2–3m thick on the surface. The method to eliminate this crack layer is polishing. The mechanism of polishing and grinding is the same, except that the tool material used is different from the slurry. The materials used for polishing include cloth, polyurethane and pitch, which usually require high precision. For the polished surface, the most commonly used material is high-grade polished asphalt.
The movement mechanism used for polishing and grinding is the same. In addition to the different polishing tools and working fluids, the environmental conditions required for polishing are also stricter than those used for grinding. The general things to pay attention to when polishing are as follows: There should be no impurities in the surface of the polishing asphalt and the polishing liquid, otherwise it will cause scratches on the mirror. The polished asphalt surface must be consistent with the laser focusing mirror surface of the lens table, otherwise it will be bounced during polishing, which will bite the polishing powder and scratch the surface of the lens.
Using asphalt to polish, the fine surface of asphalt drives the polishing liquid to grind the surface of the lens to generate heat, which makes the glass melt and flow, melt away rough vertices and fill up cracks At the bottom of the valley, the crack layer is gradually removed.
Currently, the polishing powder used for polishing glass lenses is mainly cerium oxide (CeO2). The proportion of the polishing liquid varies according to the polishing period of the lens. Generally, the initial stage of polishing Use a high-concentration polishing liquid when combining with the polishing mold. After the lens surface is bright, use a thinner polishing liquid to avoid orange peel on the mirror surface (fogging of the lens surface).
Before polishing, it must be determined whether there are scratches or punctures on the surface of the lens after polishing. Whether the size and material of the polishing tool are appropriate for the laser protective lens. Whether the hardness and thickness of the asphalt are appropriate. During the polishing process, attention must be paid to the condition and accuracy of the lens surface at all times. In the inspection of lens surface defects, because the inspection process is judged by personal vision and methods, the inspector should have a deep understanding of the specifications of scratches and sand holes, and often compare the standard samples of scratches and sand holes. To ensure the correctness of the inspection.
According to the '2015-2020 China Optical Glass Manufacturing Industry Production and Sales Demand and Investment Forecast Analysis Report' released by the Foresight Industry Research Institute, my country’s mobile phone production reached 14.57 in 2013. 100 million units, an increase of 23.27%, an increase of 18.95 percentage points over the previous year. According to IDC’s 2013 global shipments of 1.8 billion mobile phones, my country’s output accounted for 81.1% of global shipments of laser collimators, an increase of more than 10% from 2012. my country’s global mobile phone manufacturing base has The position is further stabilized.
Optical glass is mainly used for high-performance mobile phone displays, as well as the optical lens and glass parts of mobile phones with camera functions.
At present, the mainstream resolution of camera and video phone is 5 million pixels, and it is gradually increasing to 8 million pixels, 10 million pixels and other higher resolutions. Higher resolution requires more complex optical systems and more precise optical glass parts.
The introduction of autofocus and zoom functions in mobile phones will increase the number of lenses required. The general 2, 3 and 4x zoom lenses require 4 to 6, 6 to 6 respectively. 8 and 7 to 9 lenses, so the demand for optical glass components is increasing. Based on the above analysis of optical lenses, it is expected that the global demand for optical glass components for mobile phone camera functions will exceed 33.2% in the next few years.
The forecast of the demand for optical glass in the mobile phone industry
To a certain extent, the demand for mobile phones with camera functions has increased. The development of the optical lens industry has become an important driving force for the development of the optical glass industry.
Therefore, forward-looking forecasts, the demand for optical glass in the mobile phone manufacturing industry in 2014 will be 6.011 billion yuan, and by 2020 the demand will be 16.559 billion yuan. The analysis believes that with the increasing penetration rate of mobile phones and the increasing penetration rate of camera functions in mobile phones, the demand for optical glass is directly increased. Therefore, the mobile phone manufacturing industry will take into account all factors in the next few years. The demand for optical glass products and optical components industry will grow rapidly.