Back to results
US 4,514,629 AGranted
Scanning transmission electron microscopes
AssigneeNational Research Development Corporation
InventorsKenneth C. A. Smith, Stephen J. Erasmus
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeNational Research Development Corporation
InventorsKenneth C. A. Smith, Stephen J. Erasmus
Estimating the term…
In a scanning transmission electron microscope 1 the image of the diffraction pattern formed on a phosphor screen 6 as a result of electron beam impingement on a point on the specimen 4 is converted by a camera 7 into a video signal and digitized in an ADC convertor 9 and stored in a digital store 10. The stored signal is then modified by a weighting factor representing a notional pattern overlaying screen 6. The weighting factor may have one of two binary values, representing a notional opaque and transparent pattern, or may have a multiplicity of different values. The modified signals are then added together to provide a picture value for the point of impingement. By this means a complete picture is built up point-by-point. To speed up the picture taking operation diffraction images from different points may be displayed on different parts of screen 6 so that several images can be scanned together by camera 7.
A scanning transmission electron microscope including means for obtaining a video signal representing the image of a diffraction pattern derived from electron beam impingement on a point in a specimen, means for converting the video signal into digital form, a digital store for storing a plurality of digital values each representing a picture point in the said image modified by a weighting factor representing a notional pattern overlaying the screen, and means for integrating all the modified values to provide a picture value for the point of impingement of the electron beam.
Dependencies are inferred from the claim text.