Browse Prior Art Database

Scanning Electron Microscope

IP.com Disclosure Number: IPCOM000094266D
Original Publication Date: 1966-Aug-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Zeheb, D: AUTHOR

Abstract

The resolution power of a scanning electron microscope SEM is improved by the use of delay line 10. The latter is located between secondary emission pickup SEP 22 and display 24 to correlate successive picture frames and reduce random noise fluctuations.

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Scanning Electron Microscope

The resolution power of a scanning electron microscope SEM is improved by the use of delay line 10. The latter is located between secondary emission pickup SEP 22 and display 24 to correlate successive picture frames and reduce random noise fluctuations.

Electron beam 14 passes by deflection coils 16 and impinges on object 18. Coils 16 are responsive to scan generator 20. This provides a rate of scan consistent with the delay in 10. Thus identical image frames are correlated on successive scans, and random noise fluctuations are canceled. Electrons of secondary emission are sensed by SEP 22, the resultant signal passing through delay line 10 to be shown on display 24.

Delay line 10 can be replaced with circulating registers on a magnetic drum. The length of the loop of the magnetic drum would provide a delay, comparable to delay 10, and the scan rate of generator 20 would be adjusted accordingly. Another alternative is to place an A-D converter between SEP 22 and delay line
10. Delay line 10 then has to be a digital delay line. A D-A converter between delay line 10 and display 24 would convert the signal to analog form for display.

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