Technical parameters, structure, and imaging principle of inverted fluorescence microscopy
Inverted fluorescence microscope is a new type of fluorescence microscope developed in modern times, characterized by the excitation light falling down from the objective lens onto the surface of the specimen, that is, using the same objective lens as the illumination condenser and the objective lens for collecting fluorescence. A dual color beam separator needs to be added to the optical path, which forms a 45 degree angle with the light uranium. The excitation light is reflected into the objective lens and gathers on the sample. The fluorescence generated by the sample and the excitation light reflected from the surface of the objective lens and cover glass simultaneously enter the objective lens and return to the dual color beam separator, separating the excitation light and fluorescence. The residual excitation light is then absorbed by the blocking filter. If different combinations of excitation filters, dual color beam separators, and blocking filters are used, they can meet the needs of different fluorescent reaction products. The advantages of this fluorescent microscope are uniform field of view illumination, clear imaging, and stronger fluorescence with higher magnification. Inverted fluorescence microscope is an organic combination of fluorescence accessories and inverted microscope, mainly used for fluorescence and phase contrast observation of living tissues such as cells. Inverted microscopes are designed to adapt to microscopic observations in fields such as biology and medicine, such as tissue culture, cell culture in vitro, plankton, environmental protection, and food inspection. Due to the fact that these live objects being tested are all placed in culture dishes (or culture bottles), it is required that the working distance of the inverted microscope's objective lens and condenser lens is very long, which can directly observe and study the objects being tested in culture dishes. Therefore, the positions of the objective lens, spotlight, and light source are all reversed, hence the name "inverted microscope". Inverted microscopy is commonly used for colorless and transparent observation of living organisms. On the basis of inverted microscopy, a set of fluorescent accessories are added: laser excitation block, fluorescent light source, fluorescent illuminator, excitation block switching device, and inverted fluorescence observation can be performed.
The four major imported brands of microscopes all have corresponding inverted fluorescence microscopes, such as Olympus's IX71 inverted fluorescence microscope and CKX41 inverted fluorescence microscope. In recent years, with the continuous improvement of phase contrast technology and fluorescence imaging technology, domestic brand microscope manufacturers have also launched multiple inverted fluorescence microscopes. Beijing Zhongxian DSY5000X is one of them, which has high fluorescence brightness and clear imaging, approaching the level of similar mid-range microscopes abroad
