Variable light transmission filter and optical analog position sensor
Patent 4928008 Issued on May 22, 1990. Estimated Expiration Date: 
December 11, 2007. 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.
December 11, 2007. 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 2244507 2960015 3171034 3193686 3193687 3305692 3343446 3755681 3892961 Black-and-white diffractive subtractive light filter InventorsAssigneeApplicationNo. 131664 filed on 12/11/1987US Classes:250/231.1, Actuated by dynamic external physical quantity250/214PR, Photosensitive rheostat type250/237G, Gratings (moire fringes)356/617, Coded scale359/888Neutral or graded densityExaminersPrimary: Nelms, David C.Attorney, Agent or FirmInternational ClassG01D 005/34AbstractA light transmission filter for transmitting a beam of light of any wave length. The filter is made up of a pattern of opaque figures positioned along a transparent substrate. The spacing between figures is varied along the substrate so that the beam of light intercepted by the filter is variably transmitted as a selected function of the longitudinal position of the filter relative to the beam of light. The spacing of the figures along the substrate is selected to achieve a light transmission characteristic for the film in accordance with a desired mathematical function. An optical analog position sensor for sensing the position of a movable member along a prescribed path including the optical transmission filter attached to the movable member with the substrate having a longitudinal configuration corresponding to the prescribed path. The intensity of a fixed beam of light transmitted through the filter indicates the position of the member. | |
