| 摘要 |
PURPOSE:To obtain the compact illuminating system with an extremely high efficiency without having ghost images by disposing a light source to the focus of a half ellipsoidal mirror bisecting an ellipsoid, providing an aperture at the vertex and disposing a plane mirror at the bisecting plane. CONSTITUTION:The half ellipsoidal mirror 2 has the shape bisecting the ellipsoid and the inside surface thereof is formed as a reflecting surface. The light source 1 is disposed at the focus F1 thereof. The circular aperture 3 is formed around the vertex 12 and the plane mirror 4 is formed at the bisecting plane. The luminous flux emitted from the light source 1 of this constitution is reflected by the inside surface of the elliposidal mirror 2 and the plane mirror 4, is fo cused again to the focus F1 and passes the aperture 3 so as to illuminate the image to be projected formed of a liquid crystal, etc, via a condenser lens 13. The luminous flux from the light source 1 is finally emitted from the aper ture 3 even if the number of reflection times varies and, therefore, the efficiency of utilizing the luminous flux is extremely high and the system is compact. |
