Autofocus device for microreader or the like

Abstract

Abstract PURPOSE:To eliminate the eclipsing of an optical path and a deficiency in the quantity of light at the time of projection by providing a focus detection part for automatic focusing at a surface position which is off the optical path of projection and equivalent to projection plane, and switching the optical path of projection. CONSTITUTION:A focus detecting element 8 is arranged on the screen equivalent plane P slantingly above the projection optical path 9 to a screen 7. When focusing operation is performed, a 1st mirror 4 is displaced to form a focus detectable projection optical path 31 through which the negative image of a microfilm 2 is projected on the screen equivalent plane P where the focus detecting element 8 is arranged, and an image in the same focusing state with the projection image on the screen 7 and a photosensitive body is projected on the focus detecting element 8. For the purpose, automatic focusing operation is carried out by the focus detecting element 8 so that the focus detection result indicates a focusing state, and thus a normal reader projection state or print projection state is entered, thereby viewing or copying an in-focus image plane.

Inventors

• 👤 Keijirou Sakamoto
• 👤 坂本　圭治朗
• 👤 Shinichi Mori
• 👤 森　真一
• 👤 Hiroaki Nakauchi
• 👤 中内　宏彰
• 👤 Akiyoshi Hamada
• 👤 濱田　明佳
• 👤 Kazuyuki Yoshida
• 👤 和行 吉田

Bibliographic Details