US3087057A - Means for varying the picture brightness in an electron microscope - Google Patents

Means for varying the picture brightness in an electron microscope Download PDF

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Publication number
US3087057A
US3087057A US856218A US85621859A US3087057A US 3087057 A US3087057 A US 3087057A US 856218 A US856218 A US 856218A US 85621859 A US85621859 A US 85621859A US 3087057 A US3087057 A US 3087057A
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United States
Prior art keywords
varying
image
brightness
electron
electron microscope
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Expired - Lifetime
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US856218A
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English (en)
Inventor
Gutter Ernst
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Carl Zeiss AG
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Carl Zeiss AG
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    • 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
    • H01J37/26—Electron or ion microscopes; Electron or ion diffraction tubes
    • H01J37/261—Details
    • H01J37/265—Controlling the tube; circuit arrangements adapted to a particular application not otherwise provided, e.g. bright-field-dark-field illumination

Definitions

  • This invention relates to corpuscular ray apparatus and, more particularly, to corpuscular ray apparatus in which the image brightness is variable, and to an irnproved method of varying the image brightness.
  • the variation of brightness of the image in corpuscular ray apparatus was heretofore elected by varying the intensity of the corpuscular ray or beam emitted from the source of radiation.
  • the variation of beam intensity is effected by controllable adjustment of the potentials applied to one or more electrodes lying in the acceleration iield.
  • the controlled variation in electrode potential is eiected by an adjustable voltage superimposed upon the electrode bias potential.
  • the adjustable voltage source rides at the high bias potential (about 40-100 kv. in the electron microscope).
  • the adjusting dial or other meinber provided for operator control of the amplitude of the adjustable voltage must be insulated from the voltage source itself.
  • the user is always subject to the risk of a voltage -ashover at the insulator which, due to the high operating potentials, is always a possibility.
  • Another decisive disadvantage of the regulation of the image brightness by varying the intensity of the beam supplied by the beam generating system is that by a change in the potential of the control electrode, the optical conditions of the beam generating system are changed, resulting, for example, in the displacement of the position of the narrowest cross section of the beam from the object plane in which it should normally lie.
  • the corpuscular beam supplied by a beam generating system is adjusted to a iixed predetermined intensity.
  • the beam is periodically interrupted with the time of interruption variable in accordance with operator control. Since the intensity of the beam is maintained constant, any change in the electron-optic conditions is avoided.
  • the intermittent beam is used to produce the image with the average value determining the image brightness.
  • the corpuscular ray apparatus is provided with a diaphragm dening the illumination aperture.
  • Means are provided to cyclically deflect the beam across the aperture to provide an intermittent beam for image production.
  • the amplitude of the beam deflection is varied. For instance, in the case of electrostatic beam deection by increasing the applied deflection voltage, the deflection -in the plane of the diaphragm becomes greater, whereby the time of passage across the diaphragm aperture is reduced with respect to the period and thus the average value in time, which alone can be observed, of the brightness of the image is reduced.
  • deflection frequencies of more than 1,000 cycles are advantageously employed.
  • FIGURES 1 and 2 The invention will be described in further detail below with reference to the embodiments shown in FIGURES 1 and 2 in which:
  • FIGURE 1 is a cross sectioned view of corpuscular ray apparatus in accordance with the present invention.
  • FIGURE 2 is a cross sectioned view of a portion of another embodiment of a corpuscular ray apparatus in accordance with this invention.
  • FIGURE 1 there is shown an electron beam generating system comprising a cathode 1, a control or modulator electrode 2, and an anode 3.
  • the anode 3 is at ground potential, while all other electrodes are at high voltage.
  • the electron beam 4, produced by the beam generating system passes through a grounded diaphragm 5 which determines the maximum illumination aperture and impinges on the ⁇ object 6 which is to be observed.
  • a fluorescent screen 10 By means of an objective lens 7 another diaphragm 8 and a projection lens 9 an image of the object 6 is produced on a fluorescent screen 10. This fluorescent screen can be observed through a window 11.
  • an electrostatic dellection system 12 which is connected with a source o f alternating voltage 13.
  • the electron'beam is adjusted to a predetermined intensity by a suitable selection of the bias voltage of the control electrode.
  • This electron beam is periodically swept across the aperture in the diaphragm by the deection system 12. In this manner, an intermittent electron beam strikes the object 6'.
  • the average value in time of the electron beam acting on the object 6 and thus also the brightness of the image produced on the lluorescent screen llt)l is determined by varying the amplitude of the alternating voltage fed to the de ection system 12,. If, for intance, the deflection voltage is reduced, then the passage time is increased as compared with the length of the period and the image becomes brighter. Similarly, by an increase of the deilection amplitude the brightness of the image is decreased.
  • an electromagnetic deilection System 14 instead of the electrostatic deilection system 12 shown in FIGURE l, there can also be used, as shown in FIG- URE 2, an electromagnetic deilection System 14.
  • an electromagnetic deflection system consisting of two air coilsv located opposite each other which are connected in series and traversed by alternating current.
  • rIhis invention may be variously modified,and-Lem-v.v
  • An electron microscope having a beam generating ing a beam defining aperture therein, said diaphragm positioned between the anode and the object to bef" system including an anode, comprising a diaphragm havl imaged, and means for cyclically sweeping the electron beam across said aperture in a symmetrical deflection pattern, said last named means comprising means for generating an alternating deection eld and means for varying the amplitude of said eld.

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  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
US856218A 1958-11-29 1959-11-30 Means for varying the picture brightness in an electron microscope Expired - Lifetime US3087057A (en)

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Application Number Priority Date Filing Date Title
DE860557X 1958-11-29

Publications (1)

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US3087057A true US3087057A (en) 1963-04-23

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US (1) US3087057A (enrdf_load_html_response)
DE (1) DE1073655B (enrdf_load_html_response)
GB (1) GB860557A (enrdf_load_html_response)
NL (1) NL245866A (enrdf_load_html_response)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3178578A (en) * 1961-03-03 1965-04-13 High Voltage Engineering Corp Electron pulser for an x-ray tube to produce a pulsed beam of x-rays
US3795808A (en) * 1971-05-18 1974-03-05 P Knights Electron microscopes
FR2322452A1 (fr) * 1975-09-01 1977-03-25 Philips Nv Microscope electronique
US4031390A (en) * 1972-09-07 1977-06-21 Siemens Aktiengesellschaft Method of operating a particle-beam apparatus

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3008404C2 (de) * 1980-03-05 1984-07-19 Helmut 8046 Garching Formanek Verfahren und Einrichtung zum Erzeugen von Elektronenstrahl-Beugungsbildern
DE3430984A1 (de) * 1984-08-23 1986-03-06 Leybold-Heraeus GmbH, 5000 Köln Verfahren und vorrichtung zur registrierung von teilchen oder quanten mit hilfe eines detektors

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2050628A (en) * 1931-03-02 1936-08-11 Telefunken Gmbh Cathode ray television system
US2217197A (en) * 1936-12-30 1940-10-08 Bell Telephone Labor Inc Cathode ray device
US2294659A (en) * 1941-05-17 1942-09-01 Rca Corp Electron discharge device and circuit
US2330888A (en) * 1942-05-29 1943-10-05 Rca Corp Scanning microscope
US2457092A (en) * 1945-04-17 1948-12-21 American Cyanamid Co Method and apparatus for producing electron diffraction spectra
US2602751A (en) * 1950-08-17 1952-07-08 High Voltage Engineering Corp Method for sterilizing substances or materials such as food and drugs
US2820139A (en) * 1954-11-08 1958-01-14 Zenith Radio Corp Electron beam wave signal frequency converter utilizing beam deflection and beam defocusing

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2050628A (en) * 1931-03-02 1936-08-11 Telefunken Gmbh Cathode ray television system
US2217197A (en) * 1936-12-30 1940-10-08 Bell Telephone Labor Inc Cathode ray device
US2294659A (en) * 1941-05-17 1942-09-01 Rca Corp Electron discharge device and circuit
US2330888A (en) * 1942-05-29 1943-10-05 Rca Corp Scanning microscope
US2457092A (en) * 1945-04-17 1948-12-21 American Cyanamid Co Method and apparatus for producing electron diffraction spectra
US2602751A (en) * 1950-08-17 1952-07-08 High Voltage Engineering Corp Method for sterilizing substances or materials such as food and drugs
US2820139A (en) * 1954-11-08 1958-01-14 Zenith Radio Corp Electron beam wave signal frequency converter utilizing beam deflection and beam defocusing

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3178578A (en) * 1961-03-03 1965-04-13 High Voltage Engineering Corp Electron pulser for an x-ray tube to produce a pulsed beam of x-rays
US3795808A (en) * 1971-05-18 1974-03-05 P Knights Electron microscopes
US4031390A (en) * 1972-09-07 1977-06-21 Siemens Aktiengesellschaft Method of operating a particle-beam apparatus
FR2322452A1 (fr) * 1975-09-01 1977-03-25 Philips Nv Microscope electronique

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NL245866A (enrdf_load_html_response)
GB860557A (en) 1961-02-08
DE1073655B (de) 1960-01-21

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