The development of optical lens and optical glass are inseparable. The new reform of optical system often puts forward new requirements to optical lens, which promotes the development of optical lens. Similarly, the successful trial production of new types of lenses often in turn promotes the development of optical glass.
Because there are more or less defects in the processing or use performance of various new varieties of optical lenses, while studying and expanding the field of optical lenses, a lot of work has been done to improve the physical and physicochemical properties and production technology of various new varieties of optical lenses.
In recent years, China has gradually become an important optical lens manufacturing and production base in the world. Foreign enterprises have accelerated their entry into China and established joint ventures with domestic enterprises. After the tempering of fierce market competition, foreign-funded enterprises have become the main body of competition in China's optical lens manufacturing industry, followed by private enterprises.
In general, the film preparation process determines that the films have columnar microstructure, which makes certain gaps in the films and causes the instability of optical and mechanical properties of thin film devices. Therefore, various environmental tests must be carried out for some films used in special environments.
1. Constant temperature and humidity test. It is a routine environmental test. Generally, it is stored for 6-24 hours in the environment with relative humidity of 95% and temperature of 55 ℃; Or store under 40 ℃ for 10 days; Or conduct multiple cycle tests at room temperature to 80 ℃, and then detect the changes of mechanical and optical properties of the film before and after the test. For example, for narrow-band filters with high requirements, constant temperature and humidity test shall be carried out, and then the position change and peak size change of transmittance peak shall be tested.
2. Liquid etching. Generally, the film sample is immersed in a solution containing 45g salt per liter at room temperature, or in a diluted acid or alkali solution for 6-24 hours according to the user's requirements. After the test, the optical and mechanical properties of the film are tested and compared with the values measured before the test.
3. Temperature test. The thermal expansion coefficient of the film is generally one order of magnitude larger than that of the substrate. In addition, the internal stress of the film may form dislocations between the film and the film at high temperature. Therefore, when the film is used at high temperature, it must undergo baking test.