Development of a real-time stereo TEM

We have developed a real-time stereo transmission electron microscope (TEM) with tilting illumination. This system allows us to observe three-dimensional (3-D) images directly with a video-rate of 1/30 s. The system comprises two electrostatic deflectors. The first, included in the illumination system, is able to illuminate a specimen at two oblique stereoscopic angles (left and right of the optical axis) up to ±2.3 °. The second deflector, in the imaging system, is used to correct the image separation caused by defocusing of the tilted illumination. These deflectors are operated in synchronization with an NTSC video signal output from a CCD camera to record left projections on odd fields and right projections on even fields. The time series of stereo pairs is transferred to a 3-D display that enables viewing of the 3-D images without special glasses. Real-time observation of ZnO particles demonstrated that 3-D images were clear even while moving the specimen. We applied this system to observing dislocations in an Al thin film.