What Is Cover Glass

A cover glass is a thin, flat glass sheet of transparent material, usually square or rectangular, about 20 mm (4/5 inch) wide and a fraction of a millimeter thick, and placed on an object observed with a microscope. The object is usually placed between a cover glass and a slightly thicker microscope slide. The microscope slide is placed on the microscope platform or slide frame and provides physical support for the object and sliding.

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

Cover slips usually have several other functions. It keeps the sample in place (by the weight of the cover glass, 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 lens from contacting the sample, and vice versa; in an oil immersion microscope or a water immersion microscope, the cover slides to prevent contact between the immersion liquid and the sample. The cover glass can be attached to the slider to seal the sample and delay the dehydration and oxidation of the sample. Microorganisms and cell cultures can be grown directly on the cover glass before being placed on the glass slide, and the sample can be permanently mounted on the slide instead of the glass slide.

The cover glass is covered on the material on the glass slide. It can avoid the contact between the liquid and the objective lens to avoid contaminating the lens, and it can make the top of the observed cell on the same plane, that is, the distance from the objective lens is the same, so that the observed The image is clearer.