Zoom lens
Patent 5151820 Issued on September 29, 1992. Estimated Expiration Date: 
May 2, 2011. 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.
May 2, 2011. 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 3890036 Temperature compensating focusing in infrared zoom lenses Telescope objective system for the infrared range Patent #: 4494819 InventorsAssigneeApplicationNo. 694298 filed on 05/02/1991US Classes:359/354, Including continuously variable magnification or focal length (zoom lens, adjustable lens)359/356, Infrared lens359/357, Having four or more components359/676, With variable magnification (e.g., zoom type)359/679With fixed conjugatesExaminersPrimary: Arnold, Bruce Y.Assistant: Ryan, J. P. Attorney, Agent or FirmForeign Patent References
International ClassG02B 015/00Foreign Application Priority Data1990-05-18 GBAbstractA zoom lens, for use in a telescope at infra-red wavelengths or single wavelength visible light, provides a magnification which may be adjusted to either of two predetermined values. The lens comprises a pair (14) of similar elements (15, 16) fixed relative to one another and each having an aspheric convex surface with the aspheric surfaces of the pair of elements outermost. The pair of elements (14) is located between the two image planes formed in the telescope and is movable between two conjugate positions.Field of SearchIncluding alternative optical path or optical element (e.g., day-night, hi-low magnification)Including continuously variable magnification or focal length (zoom lens, adjustable lens) Lens, lens system or component Infrared lens Having four or more components With variable magnification (e.g., zoom type) With fixed conjugates Other than first group moves for focusing (internal focus type) Two groups | |
