Patent ID: 8220937
Filing Date: 2012-07-17
Classification: G03B

Abstract:
1. A projection optical system for use in a projection display for enlargedly projecting an image drawn on a display device part according to a drive signal that controls the display device part onto a projection plane while minimizing offset position error, the projection optical system comprising: a zoom adjuster comprising a zoom adjustment ring that rotates circumferentially with a lens barrel for adjusting a size of the projected image on the projection plane; and a shift adjuster comprising a tiltable transparent flat plate operably connected to a transmitting mechanism for converting a rotation drive amount of the zoom adjustment ring into a tilt direction amount of the flat plate perpendicular to the optical axis of the projection optical system in accordance with a change in the size of the projected image by the zoom adjuster, wherein the transmitting mechanism is a mechanical structure operably connected to the zoom adjuster to allow simultaneous tilting of the transparent plate with driving rotation of the zoom adjuster ring.