Method and apparatus for verification of displayed characters
Patent 4224614 Issued on September 23, 1980. Estimated Expiration Date: 
January 9, 1998. 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.
January 9, 1998. 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 T915013 3509350 3569617 3768073 3868673 3911419 Apparatus for signalling the position of a point on a surface Patent #: 4022969 InventorAssigneeApplicationNo. 05/868109 filed on 01/09/1978US Classes:345/180, Light pen for CRT display345/156DISPLAY PERIPHERAL INTERFACE INPUT DEVICEExaminersPrimary: Curtis, Marshall M.Attorney, Agent or FirmInternational ClassG06F 3/033 (20060101)AbstractA light pen detection system used in a data display system utilizes a cathode ray tube (CRT) in which characters displayed on the screen of the cathode ray tube are detected by the light pen, the detection of the character by the light pen resulting in the background inversion of the character sensed thereby providing a visual indication to the operator the character sensed by the light pen. A locking circuit is provided which, upon the sensing of a displayed character by the light pen, conditions the sensing circuits connected to the light pen to continually output the character sensed until the light pen is moved completely away from the locked character. | |
