A biconvex rod lens for the optics assembly of a medical or technical endoscope comprises of a light transmitting rod and a correcting lens cemented to one end of the rod. The rod is provided with at least one cylindrical collar which is of greater diameter than the adjacent lengths of the rod, for supporting the rod lens on the inner surface of an internal tube in the shaft of the optics assembly. In order to avoid shear forces arising in the cemented joint between the rod and the correcting lens when the shaft and thus the tube are bent when the endoscope is in use, the correcting lens and the rod have, in the region of the cemented joint, a smaller diameter than the cylindrical collar or collars. Fracture of the rod lens is there by avoided.

This invention relates to an apparatus which is used in conjunction with an endotracheal tube to provide visual information during intubation. The visual information is used by a medical practitioner in order to successfully insert and position the endotracheal tube into the trachea of a patient who is being intubated.

A ring lens assembly for an optical viewing device is presented. The ring lens assembly includes a ring shaped lens adapted for mounting at the end of an optical viewing device for viewing a remote location. The optical viewing device comprises an objective lens section, a relay lens section and an eye piece section. Further, the optical viewing device has an inner tube wherein the optics is housed and an outer tube. A plurality of optical fibers are disposed between the inner and outer tubes to provide illumination of the field of view. The ring shaped lens is a negative curvature lens or a prism-like lens for increasing the field of illumination. Alternatively, the lens is a flat lens and the optical fibers twisted to increase the field of illumination. Also, a cleaning tube is disposed between the inner and outer tubes. The cleaning tube terminates short of the end of the inner tube. An opening or channel is formed at the end of the inner tube adjacent to the cleaning tube. Accordingly, cleaning fluid travels down the cleaning tube and impacts the inner surface of the ring shaped lens. The cleaning fluid is deflected off of the inner surface of the ring lens, flows through the opening in the inner tube and impacts the outer surface of the first lens in the objective lens section thereby providing cleaning action.

A low cost optical viewing device includes an objective lens section, a relay lens section and an eye piece section. The relay lens section is devoid of glass rods and includes a minimal number of lenses each preferably fabricated from plastic material. The illumination system includes a plurality of optical fibers also preferably fabricated from plastic material.

A low cost optical viewing device for viewing a remote location comprises three sections of an objective lens, relay lens and eye piece. However, in contrast to prior art optical viewing devices, all three sections of the present invention are free of conventional and relatively expensive glass rods. The preclusion of the glass rods leads to an overall lower cost (e.g., disposable) optical viewing device (e.g, borescope and endoscope). In addition, the optical viewing device of the present invention achieves lower cost by the use of a combination of molded plastic lenses and glass lenses. In accordance with still another important feature of this invention, the method of illuminating the remote location to be viewed is accomplished by using low cost plastic optical fibers which are twisted so that the field of illumination is increased and may be tailored to match (or be no less than) the size of the field of view of the optical viewing device. Still another significant feature of the present invention is its low weight as compared to prior art devices. This low weight is obtained both through the use of the combination of lightweight plastic lenses and glass lenses as well as by the fact that the lenses are separated by an air space (as opposed to heavy glass rods). This light weight feature of the present invention leads to ease of manipulation by the end user.