Phase shift method for a TEM
US9006652B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 7, 2014 |
| Grant date | Apr 14, 2015 |
| Priority date | — |
| Expiry date | May 7, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/2802
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method of electron microcopy passes an electron beam through a phase plate, specifically a Zernike type phase plate, comprising a central hole, and a thin film causing a phase shift of the electrons passing through said film. This phase shift causes the Contrast Transfer Function (CTF) to change from a sine-like function to a cosine-like function. The phase plate is equipped with a film in the form of an annulus, carried by a much thinner film. As a result only in a small spatial frequency range (for low frequencies) the phase is changed (and thus the CTF), and for other spatial frequencies the phase shift is negligible, and thus the CTF remains unchanged. Due to the much smaller thickness of the carrier film the scattering of electrons is negligible as well.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.