An outstanding feature of optical prisms is that they can be imitated as a flat mirror system to simulate light reflection in the prism medium. Replacing mirror assemblies is probably the most useful optical prism application because they all refract or fold light and change image alignment. To achieve an effect similar to a single optical prism, multiple mirrors are usually used. Therefore, replacing several mirrors with one prism can reduce potential calibration errors, improve accuracy, and reduce the scale and complexity of the system.
Before delving into the theory of optical prisms, you should first think about its manufacturing process. In order for optical prisms to be successfully used in most applications, very strict tolerances and precision must be met when manufacturing optical prisms. Due to the variations in shape, size, and the number of most important reflecting surfaces, large-scale automated processes are completely infeasible for optical prism manufacturing. In addition, most high-precision optical prisms tend to be manufactured in small quantities, meaning that automated processes are unnecessary.
The custom optical prism first obtains a piece of glass (called "glass blank") that meets a specific grade and glass type. Then abraise the glass or pass it through a metal diamond grinding wheel to produce a nearly finished product. Most glass will form a flat but still rough surface from this stage. At this time, the size of the optical prism is very close to the required specifications. Next is the fine grinding process to remove cracks under the surface, and this stage is called fine grinding. Finally, the prisms should be polished to the specified accuracy according to the specifications.