In 1976, Olympus launched the CH Series, a modular biological microscope for practical laboratory teaching applications, in place of the KHS, KHC, HSB, and HSC.
The CH Series could meet diverse needs because of its excellent performance and modular design. The Series comprised three models: the CHA (6V 10W halogen light source), CHB (20W tungsten light source), and CHC (the mirror CH-MM or the CH-LSK 20W with a simple illumination device). The Series was painted in a warm gray color.
By switching modules, the microscope could be used for simple polarization, drawing, or incident light (metallurgical) microscopy. The CH Series used the same modules as the BH Series.