1, bright field lighting
Bright-field illumination is a commonly used illumination method for metallographic microscope. It relies on a vertical illuminator to emit light from a light source to an objective lens, and then the objective lens irradiates vertical or nearly vertical light on the grinding surface of a metallographic sample. Then the light reflected from the grinding surface of the sample is amplified vertically through the objective lens, and finally amplified again by the eyepiece. In general metallographic microscope, 45-degree inclined plane glass and total reflection prism are often used as vertical illuminators. Most of the bright field illumination systems of large horizontal metallographic microscope have these two kinds of illumination devices, and its change is realized by moving the handle back and forth or left and right. As vertical illuminators, plane glass and total reflection prism can both reflect and transmit light.

2, dark field lighting