Focusable optical instrument with a sealed optical system having no internal optical moving parts

摘要

An endoscope having an autoclavable replaceable sealed optical assembly without moveable parts. The sealed optical assembly is placed into an insertion tube of the endoscope. A focusing device is attached to the proximal end of the sealed optical assembly. The opposite end of the focusing device may be connected to an appropriate image-receiving device such as a CCD camera. The endoscope differs from conventional optical devices of this type in that its focusing is performed by shifting the image-receiving plane of the CCD camera with respect to an immobile plane of a image produced by optical elements of the sealed optical assembly.