Novel technique for spot position measurement
Patent 4025197 Issued on May 24, 1977. Estimated Expiration Date: 
May 24, 1994. 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 24, 1994. 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 2938126 3360660 3482107 3552861 3628870 InventorAssigneeApplicationNo. 05/603566 filed on 08/11/1975US Classes:356/499, Having wavefront division (e.g., by diffraction)356/401With registration indicia (e.g., scale)ExaminersPrimary: Corbin, John K.Assistant: Rosenberger, Richard A. Attorney, Agent or FirmAbstractAn optical device having a diffraction grating displaced from the focal point of a converging monochromatic beam of light for encoding the position of or measuring the displacement of an object or the light beam is disclosed. The diffraction grating, disposed a determinable distance in front of or behind the focal point of the converging light beam, generates a diffraction pattern comprising a plurality of amplitude modulated directional light beams which may be imaged with or without the aid of an intermediate lens. The angular change of the directional light beams comprising the diffraction pattern may be visually or electro-optically detected to encode or provide a measure of the relative displacement between the light beam and the grating. | |
