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:
May. 10, 1983
Filed:
Jan. 29, 1981
Akira Yonezawa, Fussa, JP;
Kohei Shirota, Akikawa, JP;
International Precision Incorporated, Tokyo, JP;
Abstract
A symmetrical magnetic field type objective lens for an electron microscope comprises an upper magnetic pole piece and a lower magnetic pole piece disposed below the upper pole piece with a predetermined inter-pole distance S. Bores of a same diameter b are formed in the upper and the lower pole pieces, respectively. The distance S and the diameter are selected so that 1.ltoreq.S/b.ltoreq.5. Additionally, excitation J of the objective lens is so selected with respect to a predetermined magnetomotive force Jc.o. of a Riecke-Ruska's condenser objective lens that the condition that 1.4 Jc.o..ltoreq.J.ltoreq.1.7 Jc.o. is fulfilled. The objective lens assures a wide field of view without being accompanied with blurs or distortion of image.