Transmission electron microscope and method for observing specimen image with the same

A transmission electron microscope comprising:

• a source for an electron beam;
• a condenser optical system that irradiates a specimen with an electron beam emitted from the source;
• a specimen holding unit that holds the specimen to be irradiated by the electron beam;
• an imaging lens system that focuses an image of the specimen;
• at least one detecting unit that obtains the image of the specimen formed by the imaging lens system;
• a first electron biprism disposed on the upstream side of the location where the specimen is placed in the electron beam traveling direction on the optical axis of an electron optical system of the transmission electron microscope;
• a third electron biprism disposed on the downstream side of the first electron biprism in the electron beam traveling direction on the optical axis of the electron optical system through one or plural lenses belonging to the condenser optical system and on the upstream side of the location where the specimen is placed in the electron beam traveling direction and set in a space at the shadow of the electron beam produced by the first electron biprism;
• and
• a second electron biprism disposed on the downstream side of the location where the specimen is placed in the electron beam traveling direction on the optical, axis of the electron optical system and set in a space at the shadow of the electron beam produced by the first electron biprism,
• wherein the first electron biprism and the third electron biprism deflect the electron beam emitted from the source and separate the electron beam into a first electron beam with a second electron beam so as to propagate in different directions for irradiating a prescribed region of the specimen from different angles,
• wherein the second electron biprism deflects the first electron beam and the second electron beam having transmitted the specimen and thereby separates a first image of the specimen produced with the first electron beam with a second image of the specimen produced with the second electron beam, and
• wherein the detecting unit obtains the first image and the second image.

A method for observing a specimen image by using a transmission electron microscope having a source for an electron beam, a condenser optical system that irradiates a specimen with an electron beam emitted from the source;

• a specimen holding unit that holds the specimen to be irradiated by the electron beam;
• an imaging lens system that focuses an image of the specimen;
• at least one detecting unit that obtains the image of the specimen formed by the imaging lens system;
• a processing device that computes the shape of the specimen from plural specimen images, and a display device,
• the method comprising:
• generating an electron beam from the source;
• deflecting the electron beam by a first electron biprism disposed in the condenser optical system, thereby separating the electron beam into two electron beams of different angles, and irradiating a prescribed region of the specimen simultaneously from the different angles;
• spatially separating the two electron beams of different irradiation angles having simultaneously transmitted the specimen by a second electron biprism disposed in the imaging lens system, focusing images individually, and obtaining two specimen images by the detecting unit;
• and
• displaying a image computed from the two specimen images on the display device.