A light microscope is an optical instrument that uses light as a source to magnify and observe tiny structures that are invisible to the naked eye. *The first microscope was made by an optician in 1604.

Polarised light is broken up into mutually perpendicular beams of equal intensity by means of a special prism. The beams pass through the object being examined at two extremely close points (smaller than the resolution of the microscope), thus differing slightly in phase, giving the image a stereoscopic three-dimensional feel.

Can make the examined object produce three-dimensional three-dimensional feeling observation effect is more intuitive. No special objective lens is required, and it works better with fluorescence observation, which can adjust the colour change of the background and the object to achieve the ideal effect.

The principle of dark field of view is based on the Tyndall phenomenon in optics, whereby fine dust cannot be observed by the human eye in the presence of strong direct light passing through it, due to the strong light bypassing it. If light is directed at it obliquely, the particles seem to increase in size and become visible to the human eye due to the reflection of light. A special accessory required for dark-field observation is a dark-field spotting scope. It is characterised by not allowing the light beam to pass through the examined object from bottom to top, but by changing the path of light so that it is directed obliquely towards the examined object, so that the illuminating light does not enter directly into the objective lens, and a bright image is formed by using the reflected or diffracted light from the surface of the examined object. The resolution of dark-field observation is much higher than bright-field observation, reaching 0.02-0.004μm.