Corrected mirror condenser for projectors - uses pair of mirrors with mutual correction of aberrations such as coma and astigmatism

摘要

A mirror condenser, is especially for slide transparency projectors. It has a main mirror which is placed adjacent to the object plane. It has its surface at an angle to the normal to the object plane at the intersect point of the objective axis. The optical system is illuminated by a lens or mirror with its optical axis at such an angle to the transmitted beam that the resulting aberrations, especially coma and astigmatism, approximately correct those of the main mirror.