MIRROR CONDENSER TYPE ILLUMINATING OPTICAL SYSTEM

摘要

PURPOSE:To improve the distribution of light quantity and to ensure the illumination of high efficiency by using a conical refractive member to invert the incident parallel luminous fluxes between the inside and the outside and at the same time correcting the inside vignetting of the parallel luminous fluxes. CONSTITUTION:A conical prism 3 having the 1st and 2nd faces 3a and 3b processed into conical convex surfaces is set at the back of a condenser lens 2. The luminous flux delivered from the lens 2 is refracted inside on the face 3a and delivered again as parallel luminous fluxes through the face 3b. The parallel luminous fluxes are shifted until the parallel beams which are most distant away from the optical axis are approximately coincident with the optical axis and that the most inside beam is delivered furthest. In other words, the incident luminous flux is inverted between the inside and the outside by the prism 3 and at the same time converted into a dense luminous flux having no vignetting at its center. This improves the distribution of light quantity and the efficiency of illumination.