Compact subjective refractive instrument
Patent 4179196 Issued on December 18, 1979. Estimated Expiration Date: 
September 30, 1997. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
September 30, 1997. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3669530 Shunt for providing a direct electrical connection Automatic refraction apparatus and method Patent #: 4105302 InventorsAssigneeApplicationNo. 05/838178 filed on 09/30/1977US Classes:351/237, Including target image projection351/241, Astigmatism type351/243IlluminatedExaminersPrimary: Corbin, John K.Assistant: Bovernick, Rodney B. Attorney, Agent or FirmInternational ClassA61B 3/13 (20060101)AbstractA compact ophthalmic instrument for refraction of patient's eyes is obtained by substantial folding of the optical system. The optical system is folded in one location using a reflection means that moves to vary the location of a target image being viewed by a patient for identifying the spherical power of a corrective lens, if any, required by the patient. A second folded portion of the optical system contains a cylinder means for cylindrically varying the target image. | |
