GB1426243A - Permanent magnet lens - Google Patents

Permanent magnet lens

Info

Publication number
GB1426243A
GB1426243A GB1133073A GB1133073A GB1426243A GB 1426243 A GB1426243 A GB 1426243A GB 1133073 A GB1133073 A GB 1133073A GB 1133073 A GB1133073 A GB 1133073A GB 1426243 A GB1426243 A GB 1426243A
Authority
GB
United Kingdom
Prior art keywords
disc
diameter
lens
plates
axially
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB1133073A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of GB1426243A publication Critical patent/GB1426243A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/02—Details
    • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
    • H01J37/10—Lenses
    • H01J37/14—Lenses magnetic
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/02—Details
    • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
    • H01J37/10—Lenses
    • H01J37/14—Lenses magnetic
    • H01J37/143—Permanent magnetic lenses

Landscapes

  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Electron Beam Exposure (AREA)
  • Magnetic Bearings And Hydrostatic Bearings (AREA)

Abstract

1426243 Magnetic focusing apparatus J B LE POOLE 8 March 1973 [10 March 1972] 11330/73 Heading H1D A magnetic fixed-focus lens includes a pair of disc-shaped permanent magnets 9 each with an electron beam aperture of diameter substantially equal to the disc thickness, the magnets being axially magnetized with opposite polarity, the spacing between magnets being between one and two times the aperture diameters and the lens having a focus substantially at the centre of one of the discs and acting to cause parallel beams to diverge. The bores of ferrous plates 7 and spacer plate 8 may be of smaller diameter than the disc apertures and the diameter of the apertures may be less than a quarter of the smallest radial cross-sectional dimension of the disc. The outer diameter of plates 7, 8 may be smaller than that of the discs to reduce stray fields and centring rings 10 are fitted within housing 6. Depending on the coercive power, plates 7, and possibly plate 8, may have axially extending polepieces (Fig. 6, not shown). The lens may be mounted in a tube 11 axially movable in the evacuated space of an electron microscope. One or more lens systems may be displaced axially to control the magnification. Materials of high coercive force (e.g. >1400 oersteds) may be compounds or alloys of cobalt with rare earths or platinum. The external disc diameter may be 20 mms. Reference is made to groups of lenses in a rotatable housing and the equivalents of optical "zoom" lenses. Chromatic aberration and image distortion correction is mentioned.
GB1133073A 1972-03-10 1973-03-08 Permanent magnet lens Expired GB1426243A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7203264A NL7203264A (en) 1972-03-10 1972-03-10

Publications (1)

Publication Number Publication Date
GB1426243A true GB1426243A (en) 1976-02-25

Family

ID=19815571

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1133073A Expired GB1426243A (en) 1972-03-10 1973-03-08 Permanent magnet lens

Country Status (5)

Country Link
US (1) US3812365A (en)
JP (1) JPS48103270A (en)
DE (1) DE2311578A1 (en)
GB (1) GB1426243A (en)
NL (1) NL7203264A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2192092A (en) * 1986-06-25 1987-12-31 Philips Electronic Associated Magnetic lens system
WO2011089439A3 (en) * 2010-01-21 2011-11-17 Nfab Limited A miniature low- energy electron beam generator

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3984687A (en) * 1975-03-17 1976-10-05 International Business Machines Corporation Shielded magnetic lens and deflection yoke structure for electron beam column
GB1594465A (en) * 1977-03-23 1981-07-30 Nat Res Dev Electron beam apparatus
JPS5953658B2 (en) * 1980-01-30 1984-12-26 株式会社日立製作所 electronic lens
US6201251B1 (en) * 1998-08-28 2001-03-13 Nikon Corporation Compensation of space charge in a particle beam system
CN101461026B (en) 2006-06-07 2012-01-18 Fei公司 Slider bearing for use with an apparatus comprising a vacuum chamber
JP6323943B2 (en) * 2013-02-27 2018-05-16 株式会社Ｐａｒａｍ Electron lens and electron beam device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2192092A (en) * 1986-06-25 1987-12-31 Philips Electronic Associated Magnetic lens system
WO2011089439A3 (en) * 2010-01-21 2011-11-17 Nfab Limited A miniature low- energy electron beam generator

Also Published As

Publication number Publication date
JPS48103270A (en) 1973-12-25
NL7203264A (en) 1973-09-12
US3812365A (en) 1974-05-21
DE2311578A1 (en) 1973-09-20

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Legal Events

Date Code Title Description
CSNS Application of which complete specification have been accepted and published, but patent is not sealed