An endoscopic telescope has a system tube in which spacer tubes are alternatingly stacked with rod lenses each having an external diameter smaller than the inside diameter of the system tube and which have convex end faces supported against the axial ends of the spacer tubes. An end of at least one of the spacer tubes protrudes axially at an angle and at a rotational position so that it abuts the adjacent convex surface of a rod lens, thereby tilting the rod lens relative to the system tube axis. The spacer tubes and the rod lenses are mounted spring loaded between end holding devices in the system tube.

An endoscope optics is fitted with a rigid stem and an objective lens is received in a distal end of the stem. The stem also receives an image transmission device for transmitting images away from the objective lens toward a proximal end of the stem. The image transmission device consists of a plurality of spaced apart optical lenses. At least one ofthe plurality of spaced apart lenses is made of sapphire.

A relay lens for an endoscope or optical instrument is shown. The relay lens includes a first rod-type lens element having a first end and a second end. The first end defines a substantially spherical surface and the second end defines a convex surface. An optical element is positioned in axial alignment with and adjacent the first rod-type lens element. The optical element has a concave surface and a convex surface. The concave surface of the optical element is bonded to the convex surface of the second end of the first rod-type lens element forming a single bonded gap between the concave and convex surfaces. A second rod-type lens element having a first end and a second end, wherein each of the first end and second end defines a substantially spherical surface, is positioned in an axially aligned relationship with the first rod-type lens element and spaced from at least one of the first end of the first rod-type element and the concave surface of the optical element. A method of manufacturing a relay lens is also shown.

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 molded plastic lenses rather than the more expensive glass lenses used in prior art devices. 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 lightweight plastic 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.

An endoscope has an endoscope tube and a lens system arranged in the endoscope tube. The lens system has endoscope lens components and air gaps between the lens components. An illumination system is arranged within the endoscope tube. The endoscope lens components each have an axial lens length; the endoscope lens components include first lens components and second lens components, wherein the axial lens length of the first lens components is the shortest axial lens length, respectively, and wherein the axial lens length of the second lens components is longer than the shortest axial lens length. The first lens components with the shortest axial lens length are arranged in an area of an axial center of the endoscope tube. The second lens components having the longer axial lens length have a first half and a second half and an air gap arranged between the first and second halves.