| 摘要 |
PURPOSE:To obtain efficient illumination suppressing the reduction of the intensity of illumination due to the positional shift of an optical source by combining two ellipsoidal surfaces of a reflector and allowing light from a light source to irradiate an original as about parallel light flux. CONSTITUTION:The center 21 of the light source 20 is shifted in the X and Y directions of respective 1st focuses F1a, F1b. Therefore, the light projected from the light source 20 and reflected on the ellipsoidal surface 12 of the ellipsoidal reflector 10 forms parallel light flux and is reflected by a plane mirror 14 to illuminate the original on the original placing glass 25 around the focus F2. The light reflected by an ellipsoidal surface 11 forms parallel light flux and illuminates the original directly around the focus F2. Since the ellipsoidal surfaces 11, 12 of the mirror 10 are combined, the light from the light source 20 is reflected by the mirrors 10, 14 and iluminates the focus F2 under the square state similar to the parallel light flux. Even if the center position of the light source 20 is slightly shifted from the point 21, the reduction of the intensity of illumination at the part of the focus F2 is extremely suppressed. |
