| 摘要 |
PURPOSE:To reduce the size and to improve the light convergence efficiency by using the parabolic mirror as a main mirror and providing an auxiliary reflecting mirror which reflects light from a light source toward the light source without any loss at the open end part of the parabolic mirror. CONSTITUTION:A spot light source is placed at a focus F, the depth of the main mirror 11 consisting of the parabolic mirror is represented as the angle X, centered on the focus F, from a vertex P that an optical path O passes to the open end Q, and this angle X is set to >=90 deg.. Further, an auxiliary spherical mirror (auxiliary reflecting means) 13 is provided at the open end part of the main mirror 11 and reflects the light from the light source to the light source and its projection aperture diameter D1 is set substantially equal to the open end part diameter phi3 of the main mirror 1. The light has loss or irradiates a nonillumination area more in the case of unsatisfying the above conditions. Consequently, the device which is high light utilization efficiency and reducible in size is obtained. |
