Patent ID: 8748819
Filing Date: 2014-06-10
Classification: H01J

Abstract:
1. A transmission electron microscopy system having an optical axis, wherein the transmission electron microscopy system comprises: an illumination system configured to direct electrons onto a location within a sample plane such that the electrons are incident at this location only from directions having an angle relative to the optical axis which is smaller than an outer cone angle; an objective lens system having an object plane located in the sample plane and a diffraction plane corresponding to the object plane; a first projection system imaging the diffraction plane into a first intermediate diffraction plane; a second projection system imaging the first intermediate diffraction plane into a second intermediate diffraction plane; a first aperture having a central opening, wherein the central opening is defined by an outer edge extending along a circle having a first radius about the optical axis, wherein the first aperture is located in the first intermediate diffraction plane; and either a bright field detector located in the second intermediate diffraction plane and having a detection surface defined by an inner edge extending along a circle having a second radius about the optical axis, or a bright field detector and a second aperture located in the second intermediate diffraction plane and having an opening defined by an outer edge extending along a circle having a second radius about the optical axis and wherein the bright field detector is disposed in the beam path downstream of the second aperture; wherein the first radius defines a maximum angle relative to the optical axis of directions of bright field electrons traversing the sample plane and detectable by the bright field detector; and wherein the second radius defines a minimum angle relative to the optical axis of directions of bright field electrons traversing the sample plane and detectable by the bright field detector.