Generation and removal of maintenance fog in optical microscope
There are also many factors for the generation of fog. Fog can be divided into oily fog, water-based fog and oil-water mixed fog. Its formation is related to the structure of the instrument, sealing performance, chemical stability of the glass, temperature, humidity, stability of grease, and the fat content of auxiliary materials, especially in the assembly operation.
water mist formation
(1) The glass is not wiped clean or the auxiliary materials are not clean. After a long time, when there is humid air, the traces along the wiping direction will form a fog like wiping the table with a wet towel.
(2) The dust in the air enters the instrument and falls on the glass, forming crystal cores and forming mist beads.
(3) The tightness of the instrument is poor, or the shell of the instrument has air leakage sand holes, so that when the moist air enters the optical instrument and encounters the dew point temperature, the fog beads will appear on the glass surface. In addition, small insects crawl into the instrument and cause fogging.
(4) The chemical stability of the glass material is poor, and it is easy to precipitate inorganic salts after being damp, and then absorb moisture to form fog.
(5) Because the optical glass is moldy, the secretion of the mold will also form a water-based fog.
(6) Water-based fog is formed due to the humid environment where the instrument is placed.
oily mist formation
After the optical parts are contaminated with oil (gasoline, engine oil, grease, animal oil, vegetable oil, etc.), if they are degreased or not wiped clean, oily mist will appear over time, and even large fog beads will form. The specific formation factors are as follows:
(1) The shaft material has a high fat content, or the container is not cleaned after contamination. If this auxiliary material is used to wipe the optical parts, oily mist will be generated.
(2) Gasoline oil pollution from cleaning metalworking parts or grease splashes on the optical parts to form oily mist.
(3) When assembling roll-pressed metalworking parts, the oily mist caused by oily mist is not wiped and degreased after the optical parts are polluted by oil on tools or hands.
(4) Oily mist is formed due to the diffusion of various oil molecules to the surface of optical parts. The volatilization of various grease vapors will also condense into oily mist when it encounters the surface of optical parts. Sometimes, due to segregation and deterioration of oil, oil volatilization, diffusion, oil flow and other phenomena are caused, thus forming oil-to-oil ratio fog.
(5) Due to the poor sealing of the product structure, or excessive filling of grease, it will cause oil mist or oily mist due to improper use and storage.
Formation of the Mixed Realm
Intuitively, there are obvious differences between oily mist and watery mist, but when some are like oily mist and watery mist, they are called mixed fog. It is produced under the conditions of both oil mist and water mist formation.
How to prevent mold and fog:
From the analysis of the causes of the mold fog described above, it can be known that, on the one hand, it is due to the poor chemical stability of optical glass. On the other hand, it is caused by insufficient attention to civilized production in the assembly process, and on the other hand, it is caused by poor use and storage. In particular, about 70% of the production process or repair process did not pay attention to clean production, causing mildew and fogging. It can be seen that clean operation is an important link to prevent mold and fog. In addition, technical measures such as ultra-clean workbench, electrostatic dust removal equipment, ultrasonic cleaning, double anti-film coating, and application of anti-mold agents are all necessary to maintain the quality of optical parts. effective measures.
(1) Treating optical glass parts with ethyl hydrogen-containing dichlorosilane (monomer) can obtain a good water-increasing layer, which acts as an anti-fog effect. Using it to clean the glass will look particularly refreshing and bright, which can effectively Thoroughly remove the "slobber circle", finger prints and some oil spots on the glass surface. It can also reduce the consumption of working hours and auxiliary materials, and improve the quality of products.
(2) The new process of pickling-steaming optical parts is used instead of manual glass cleaning. After years of practice, good results have been achieved. Its characteristic is.
① After the optical parts are pickled, the oxides on the surface of the parts and the nutrients for the growth of mold can be removed, so as to prevent and reduce the generation of mold fog.
②The production efficiency is high, which is 2-3 times higher than that of manual work. Even if there are individual marks, just wipe it with a cotton ball to clean it.
③Good quality, the glass wool surface is the birthplace of mold growth, after pickling, the surface is fresh and clean.
In order to improve the chemical stability of the glass, various double anti-coatings can be dip-coated during the processing. For glass with better chemical stability, 49' glass anti-fog layer or anti-fog film layer of Xu ethyl hydrogen-containing dihydrogen silane can be dipped. For glass with poor chemical stability, it can be vacuum-coated with mgF: film and then coated with SF20972 anti-protective layer or vacuum-coated with F46 polyperfluoroethylene propylene optical three-proof film, which are all effective methods.
In order to improve the anti-fog ability of the glass surface, the lens of the first and second types of glass can be wiped with a mixture of 0.25% ethylhydrogen-containing dihydrosilane during assembly, which can not only remove the fogging core (watermark, saliva circle, etc.) Surface strength, the effect is better. For lenses with good chemical stability, 0.25% ethyl hydrodichlorosilane or appropriate amount of 49' glass anti-fog agent can also be infiltrated into the ultrasonic cleaning solution to make it have an anti-fog film layer.
Chemical treatment:
Chemical drugs are used to kill or inhibit bacteria. Commonly used antifungal agents are divided into two types: contact and volatile. The former is to add mercuric acetate or 8-methanolin copper or dimethyl saliva to the dustproof grease, moistening grease, and sealing wax, and it can also be soaked in organic solvents to soak pressure rings and other parts. The latter is p-nitrobenzaldehyde, which is harmless to humans, has a long effective time and is easy to process. When in use, press it into a tablet, wrap it with a plastic film, and tie a few air holes, and paste it in a place that does not affect the optical path in the instrument, which can prevent mildew, but requires good sealing of the instrument structure.
