Why is an inverted microscope an "inverted" microscope?
The composition of an inverted microscope is the same as that of an ordinary microscope, except that the objective lens and the illumination system are reversed. The object is located in front of the objective lens, and the distance from the objective lens is greater than the focal length of the objective lens, but less than twice the focal length of the objective lens. After passing through the objective lens, an inverted magnified real image is formed. What our eyes see through the eyepiece is not the object itself, but the image of the object that has been magnified once by the objective lens.
Since the materials observed by inverted microscopes are generally cultured cells, which are highly transparent and have no obvious structural contrast, inverted microscopes are often equipped with phase contrast objectives, which actually constitutes an inverted phase contrast microscope.
On inverted microscopes, various types of consumables such as petri dishes and multi-well plates are often used, and the bottoms are of different thicknesses, which will cause certain changes in the passage of light. At this time, an objective lens with a correction ring function must be used. An adjustment ring is installed in the middle. When the adjustment ring is turned, the distance between the lens groups in the objective lens can be adjusted to correct the movement caused by the cover glass (Petri dish). ) Aberration caused by non-standard thickness (conventional petri dish is 1.2mm, cover glass is 0.17mm). The correct method of use is: adjust the correction ring to the standard value of 1.2mm and focus on the sample. Move the correction ring half a step to the right and focus on the sample. If the image effect becomes better, move the correction ring to the right and focus again. Otherwise, move it to the left.
The inverted biological microscope realizes dual-channel function. The new infinity light path of the product allows you to introduce additional light sources to implement technologies such as FRAP, photoactivation, laser ablation, laser tweezers or optogenetics.
The inverted microscope was born to adapt to microscopic observation of tissue culture, cell culture in vitro, plankton, environmental protection, food inspection and other fields in biology, medicine and other fields. Due to the special limitations of these samples, the objects to be inspected are placed in petri dishes (or culture bottles), which requires the objective lens and condenser of the inverted microscope to have a long working distance to directly microscopy the objects in the petri dish. Observe and study. Therefore, the positions of the objective lens, condenser and light source are all reversed, hence the name "inversion".
