Optical mark sense detector
Patent 4162408 Issued on July 24, 1979. Estimated Expiration Date: 
October 17, 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.
October 17, 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 3675201 3692982 3692983 Adaptive and programmed threshold level detection arrangement Apparatus utilizing analog-to-digital conversion in the photoelectric reading of documents Patent #: 3983364 InventorAssigneeApplicationNo. 05/842656 filed on 10/17/1977US Classes:250/555, Including coded record382/270, Variable threshold, gain, or slice level434/358Light detector sensing responseExaminersPrimary: Tokar, M.Attorney, Agent or FirmInternational ClassesH03K 5/153 (20060101)G06K 7/10 (20060101) AbstractApparatus for detecting marks or other objects by comparing a decrease in reflected light while the mark or object is moving across optics, to the light reflected before the mark or object was encountered by the optics. A threshold reference voltage level is derived directly from the conductance level of a phototransistor prior to the introduction of the mark or object to be detected. This reference level is developed in such a manner as to cause it to be a dynamic voltage, varying percentage-wise as the conductance of the photo-transistor. The dynamic reference level so determined is thus always directly a portion of the level present before the mark or object to be sensed was introduced.Field of SearchIncluding coded record | |
