Phase-compensating vibration cancellation system for scanning electron microscopes
Patent 5049745 Issued on September 17, 1991. Estimated Expiration Date: 
August 13, 2010. 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.
August 13, 2010. 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 ReferencesVibration cancellation system for scanning electron microscopes Patent #: 4948971 InventorsAssigneeApplicationNo. 566591 filed on 08/13/1990US Classes:250/310, Electron probe type250/306, INSPECTION OF SOLIDS OR LIQUIDS BY CHARGED PARTICLES250/307, Methods250/311Electron microscope typeExaminersPrimary: Berman, Jack I.Attorney, Agent or FirmInternational ClassH01J 037/28AbstractA system for adjusting the scanning pattern of an electron beam in a scanning electron microscope to decrease image sensitivity to vibrations. In the system, a seismometer is connected to sense displacement velocity caused by vibrations, an integrator is provided for integrating signals from the seisometer, and a phase compensation system is provided for operating upon the integrated signals to provide phase compensated signals that are substantialy 180 degrees out of phase with the sensed vibrations. The phase-compensated signals are used for adjusting the normal scanning pattern of the electron beam microscope to reduce the effects of the sensed vibrations on images provided by the microscope. | |
