Electron microscope
AssigneeHitachi, Ltd.
InventorsShoji Kamimura, Yasushi Saito
Life of this patent
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Abstract
A condenses lens system condenses an elctron beam onto a specimen. The electron beam thus transmitted through the specimen is magnified by a magnifying lens system. The magnified electron beam is projected onto a fluorescent screen, and the image of the specimen is visually observed. The quantity of electrons per unit area in the magnified electron beam is detected by an electron beam detector. In response to the detected signal, the condenser lens system is controlled so as to make constant the quantity of electrons per unit area in the magnified electron beam.
Claims12
An electron microscope comprising means to radiate an electron beam, means to condense said electron beam from the radiation means onto a specimen, means to magnify the electron beam having been transmitted through said specimen by condensing said electron beam onto said specimen, means to convert the magnified electron beam into a visual specimen image, means to detect said magnified electron beam and to convert it into an electric signal, and means to control the condensing means in response to said electric signal so that a quantity of electrons per unit area in said magnified electron beam is held substantially constant.
An electron microscope comprising means to radiate an electron beam, means to condense said electron beam from the radiation means onto a specimen, means to magnify the electron beam having been transmitted through said specimen by condensing said electron beam onto said specimen, means for observing the magnified electron beam as a visual specimen image, the observation means being arranged at a position on which said magnified electron beam is projected, means to detect said magnified electron beam as an electric signal which is proportional to a quantity of electrons per unit area in said electron beam, and means to controlthe condensing means in response to said electric signal so that said quantity of electrons per unit area in said magnified electron beam is held substantially constant.
An electron microscope comprising means to radiate an electron beam, condensing means to condense said electron beam from the radiation means onto a specimen, means to magnify the electron beam having been transmitted through said specimen by condensing said electron beam onto said specimen, means for observing the magnified electron beam as a visual specimen image, the observation means being arranged at a position on which said magnified electron beam is projected, means to detect said magnified electron beam as an electric signal which is proportional to a quantity of electrons per unit area in said electron beam, means to subject said electric signal to a logarithmic transformation and produce a corresponding output signal, means to generate a variable d.c. signal, means to subject said variable d.c. signal to a logarithmic transformation and produce a corresponding output signal, means to add output signals of both the logarithmic transformation means and produce a corresponding output signal, and means to control said condensing means in response to an output signal of the adding means so that said quantity of electrons per unit area in said magnified electron beam is held substantially constant.
Dependencies are inferred from the claim text.