Door wicket or viewing port with polarizing lens
Patent 4719720 Issued on January 19, 1988. Estimated Expiration Date: 
July 3, 2006. 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.
July 3, 2006. 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 1737291 2229594 2262203 2304995 2491758 2638810 3281965 3521940 3880496 Training aid for use with night vision apparatus InventorApplicationNo. 06/881916 filed on 07/03/1986US Classes:49/171Viewing, ventilating, or packet passageExaminersPrimary: Kannan, Philip C.Attorney, Agent or FirmInternational ClassesE06B 7/00 (20060101)E06B 7/30 (20060101) AbstractA viewing port for doors such as residences including a light polarizing assembly including at least two linear polarized optical elements, one mounted for rotation with respect to the other element(s) to change the viewing port from light passing to light blocking or reduced transmission condition. The light polarizing assembly is located at the inner side of the door and is surrounded by a tapered portion of its mounting toward the outer face to provide undistorted wide angle viewing of the area surrounding the door. In another embodiment of this invention, my viewing port is designed to be integrated into a stained glass window. | |
