The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 02, 1986
Filed:
Jun. 10, 1985
Takeshi Tomita, Tokyo, JP;
Yu Ishibashi, Tokyo, JP;
JEOL Ltd., Tokyo, JP;
Abstract
When a transmission-type electron microscope is used to make an observation of a diffraction image produced by a focused electron beam, it is desired that the divergence angle of the electron beam be varied at will while maintaining the spot diameter of the beam on a specimen constant. The present invention provides three stages of focusing lenses and a means for controlling these lenses in interrelated manner in a space between an objective lens and an electron gun in which the specimen is placed. The three stages of lenses are designed to be controlled independently. When an operation is performed to increase the divergence angle of the electron beam, the excitations of the first and second stages of focusing lenses are reduced while the excitation of the third stage of focusing lens is increased, thus maintaining the spot diameter of the beam on the specimen constant.