illustrate:

Schematic diagram of pentagonal prism

Dawei prism is mainly used for image rotation. It can make the image rotate, stand upside down or reflect backward. After the light enters from one of the inclined planes, it will produce total reflection on the longest bottom surface, and then emitted from the opposite inclined plane. Light is reflected only once, so the imaged image is reversed.

When the prism rotates, the resulting image rotates at twice the angular rate. Dowell prism can easily and accurately rotate the beam, and its slender and square shape makes it easy to install. Another use is retroreflection. At this time, the prism is equivalent to a right angle prism.

The types and general data are as follows: