1. Field of the Invention
The invention relates to an objective for endoscopes, in particular for endoscopes having a lateral objective lens, consisting essentially of at least a prism, a diaphragm and a negative lens forming the distal delimitation of the objective, the prism being provided with reflective surfaces and the negative lens as well as the diaphragm being joined together and being situate on the same axis. The invention furthermore relates to a process for the production of objectives for endoscopes of this type.
2. Description of the Prior Art
Known objectives for endoscopes generally comprise a rod-shaped prism installed in a metal mounting and a diaphragm with a negative lens positioned at the distal end beyond the prism. It is necessary in this connection, in order to obtain the desired optical qualities such as direction of view, angle of view, resolution and sharpness as far as the edge of the image field, to maintain extremely close tolerances and eccentricities of the mutually aligned axes during production and assembly. To accomplish this, the diameter of such objectives could not be smaller than about 2.7 mms, although even smaller diameters are required in practice.