OPTICAL SYSTEM FOR VARYING FOCAL POINT REFRACTIVE POWER ALONG ONE MAIN LINE WHILE MAINTAINING CONSTANT FOCAL POINT REFRACTIVE POWER ALONG ANOTHER MAIN LINE

摘要

An apparatus, including a pair of spaced-cylinder lenses having their cylinder axes in one plane with a third cylinder lens slideably mounted on a carriage therebetween and having its cylinder axis positioned normal to the plane, permits the focal power in one principal meridian to be continuously varied by moving the carriage with the third cylinder lens. The lenses are supported by a rotatable assembly and the slideable carriage is supported by a track running parallel to the optical axis.