The schematic illustration of JEM-2010F objective lens in Figure 4537 presents the typical objective lens in conventional TEMs. The specimen (for side-entry holder) is located at the center of the polepieces. Thee objective aperture (OA) is placed immediately below the specimen and the high contrast (HC) aperture goes through the lower polepiece.
Figure 4537. Typical objective lens in conventional TEMs.
The main advantage of the high contrast aperture is it permits high contrast imaging (similar function to that of objective aperture), and simultaneous EDS and high angle tilt of TEM specimen.