The Function Of The Microscope Cover Glass

The main function of a coverslip is to keep the solid sample flat and the liquid sample formed into a flat layer of uniform thickness. This is necessary because the focus of high-resolution microscopy is very narrow.

Coverslips often have several other functions as well. It keeps the sample in place (by the weight of the coverslip or, in the case of a wet installation, by surface tension) and protects the sample from dust and accidental contact. It protects the microscope objective from contacting the sample and vice versa; In an oil-immersion microscope or water immersion microscope, lid sliding prevents contact between the immersion solution and the sample. The coverslip can be applied to the slide to seal the sample, delaying dehydration and oxidation of the specimen. Microorganisms and cell cultures can be grown directly on a coverslip before being placed on a slide, and samples can be permanently mounted on a slide instead of a slide.