| 摘要 |
<p>An endoscope relay optics design that reduces the number of air surfaces while maintaining high levels of correction. A lens assembly (20) for incorporation into an optical transfer system (where two such assemblies define an optical transfer module for transferring an image between successive image planes) is of unitary construction. The assembly comprises five elements including a central rod-like element (22) of high index material, a pair of negative elements (25) of relatively low index, high dispersion material cemented to opposite ends of the central element, and a pair of positive end elements (27) of high index, low dispersion material cemented to the negative elements. The powers of the elements are determined by requiring the Petzval sum to assume a desired low value, with index difference being the primary contributor to the correction. The two exposed surfaces are flat or mildly concave and include an aspheric component to correct spherical aberration.</p> |
