DD143187A1 - Protection of a catode in electron beam instruments - Google Patents

Protection of a catode in electron beam instruments Download PDF

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Publication number
DD143187A1
DD143187A1 DD21316279A DD21316279A DD143187A1 DD 143187 A1 DD143187 A1 DD 143187A1 DD 21316279 A DD21316279 A DD 21316279A DD 21316279 A DD21316279 A DD 21316279A DD 143187 A1 DD143187 A1 DD 143187A1
Authority
DD
German Democratic Republic
Prior art keywords
cathode
electron
characterized
item
device according
Prior art date
Application number
DD21316279A
Other languages
German (de)
Inventor
Hans-Joachim Doering
Jens Jacob
Alfred Salwender
Karl-Heinz Schulz
Hans Zapfe
Original Assignee
Doering Hans Joachim
Jens Jacob
Alfred Salwender
Schulz Karl Heinz
Hans Zapfe
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 Doering Hans Joachim, Jens Jacob, Alfred Salwender, Schulz Karl Heinz, Hans Zapfe filed Critical Doering Hans Joachim
Priority to DD21316279A priority Critical patent/DD143187A1/en
Publication of DD143187A1 publication Critical patent/DD143187A1/en

Links

Classifications

    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/84Traps for removing or diverting unwanted particles, e.g. negative ions, fringing electrons; Arrangements for velocity or mass selection
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/46Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/48Electron guns
    • H01J29/484Eliminating deleterious effects due to thermal effects, electrical or magnetic fields; Preventing unwanted emission

Description

- "213 f

Title:

Protective device of a cathode in electron beam devices

Applicability of the invention:

The invention relates to a device for deflecting positive ions to electron beams, which serves to protect the cathode by reducing the ion bombardment.

This device can be used in electron beam devices in which stable precursor electron probes require a precise stationary position of the electron source, e.g. for electron beam and electron beam exposure apparatus.

Characteristic of the known technical solutions:

Are known asymmetric systems of ion traps in electron beams, using a bent by magnetic or electrical means electron beam is used (eg in E.Bas: Optics 12, (1955) 8, p.377-384 and Rint: manual for HP and electrical engineers) , On. such beam path deteriorates the focus and thus the image quality in electron probe devices because of asymmetric deflection and lens aberration.

213

Furthermore, axial ion trap systems are known which do not disrupt the nighttime rush of the unbalanced systems. These systems operate e.g. with axialsy-mmetrischer guidance of the electron beam by electrostatic means which are arranged around an attached in the optical axis ion trap (eg US-PS 3,452,241) The wax part of this system is that it is very expensive in terms of electrodes and the corresponding supply voltages Especially when the demands on the quality of the electron beam are high.

In electron emitters without Ionenablankung an ablation of the cathode tip u.a, by Katodenbeschuß specified by the manufacturer, the adverse effect - decrease the directional beam v / er tes - the user of the radiator by readjusting the cathode, korrigier s must. For this purpose, the electron beam device must be taken out of service and the spotlight to be dismantled. This technique is expensive, can lead to the destruction of embrittled Katodenteile and reduced depending on the stability requirement of the electron beam device whose availability more or less. The original directional beam value can not be reliably adjusted by readjusting the cathode.

Aim of the invention; '

The aim of the invention is to reduce the technical complexity of devices of the type mentioned and Nachjustieraufwand or .. to eliminate the Nachjustieraufwand, and to increase the availability of radiators and the life of cathodes in radiators with reduced effort.

3460

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.3. 2Γ3 162

Presentation of Article 3 of the Invention:

The invention has for its object to provide a way that the life of cathodes is increased by protecting the cathode tip from positive ions and thereby the orbits of the electrons are not interfered with.

In an apparatus for deflecting positive ions on an electron gun to protect the cathode from ion bombardment, the object according to the invention is therefor. solved by that the cathode is surrounded by a magnetic ring system and a * rotationally symmetrical PeId around the electron-optical axis, which diverges from the cathode to the anode of the electron gun. It is advantageous if the magnetic ring system consists of two permanent magnet rings, which are surrounded by a ring-shaped magnetic yoke and between which there is a variable air gap. Another favorable solution is to form the magnetic ring system as an axially magnetized permanent magnet ring, which is arranged in an annular pole shoe.

Furthermore, the rotationally symmetric field can be generated by the magnet system of an atomizer pump integrated in the electron gun. The effect of the device is based on the fact that the rotationally symmetric magnetic field line course diverging towards the anode causes a defocusing on the positive ions and reduces the ion current density on the cathode tip.

Embodiment ;

In the following the invention with reference to embodiments and the accompanying drawings, in the

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213 162

  - 4 -

1 shows a device with a magnetic ring containing two magnet rings and

FIG. 2 shows a device with a magnetic ring tag containing only one magnetic ring and pole ring rings.

on average, will be explained in more detail.

The apparatus shown in Fig. 1 consists of two magnetic rings 1 and 2, which are arranged axially parallel to a fixed in a holder 3 cathode 4 of an electron gun. In the air gap of the magnetic rings 1 and 2, which are surrounded by a magnetic yoke 5, the discharge system 6 of an integrated Zerstäuberionenpumpe is arranged.

For the purpose of adjusting the electron emitter to the electron-optical axis 7 of the electron beam device, two adjusting screws 8 are provided, with the aid of which the magnetic rings 1 and 2 of the magnetic ring system can be moved radially.

The mode of operation of the device is based on the fact that a diverging magnetic field 11 existing in the space 9 between the cathode 4 and the anode 10, which is represented by its field line profile, is located on charge carriers close to the axis 12 due to the radial components of the magnetic field 11 compensating there On electrons of the carrier beams 12, which move relatively close to the axis 7, the magnetic field 11 thus has no negative influence. Near the anode 10, the electrons are accelerated so high that even the divergent negative parts of the carrier beams 12 by the transverse component of the there relatively weak magnetic field 11 are hardly affected. From the lying under the anode 10 space 13 of the radiator with higher pressure than in space 9 positive ions mch the known cosine distribution through the anode hole in the

3460

213 162

Spotlight space and are accelerated in the direction of the cathode 4. Due to their large mass, the relatively weak magnetic field hardly collects on ions close to the axis. Obliquely incident positive ions, which are represented as rays 14, are further scattered by the magnetic field 11 diverging outside Acsense 7, in particular just above the anode 10 in space 9, where the ions are not yet accelerated, so that at the location of the tip Katode 4 the total ion density is reduced. As a result, damage to the cathode are greatly reduced.

Figure 2 shows a device which consists of an arranged around the cathode 4, axially magnetized permanent magnet ring 15, which is surrounded by a Polschuhringsystem. The Polschuhringsystem consists of a fixed Polschuhring 16 and four adjustment screws 17, which serve for .Perschiebung of the magnetic ring 15 and for adjusting the electron beam to the axis of the electron beam device, and from an adjustable Polschuhring 18, with the help of the annular gap 19 and thus the stray field in Set area of the cathode 4. An axial adjustment of the magnetic ring 15 to the cathode 4 is possible by means of a collar 20. The mode of action of the device according to Pig. 2 is analogous to the standing Fig. 1; this is also due to the fact that due to the rotationally symmetric, diverging to the anode magnetic FeIdlinienverlaufs causes a defocusing on the positive ions and the ion current density is reduced on the cathode tip.

3460

_ _ 2 ί 3 1 6 2

'I.Erfindun & sanspruch

1. Device 2ium deflecting ν on positive ions at an electron gun to protect the cathode from ion bombardment, characterized in that the. Cathode is surrounded by a magnet system 'and a rotationally symmetrical Pond around the electron-optical axis, which diverges from the cathode to the anode of the electron beam.

2. Device according to item 1, characterized in that the magnetic system consists of two magnetic rings per manent, which are surrounded by a ring-shaped magnetic return and rule between which there is a variable air gap.

3. Device according to item 1, characterized gekennaeichnet,. the magnet ring system consists of an axially magnetized permanent magnet ring which is arranged in an annular pole shoe.

4. The device according to item 1, characterized in that the rotationally symmetrical PED is generated by the magnetic system of an integrated in the electron gun Zerstäuberionenpumpe.

5. The device according to item 1, characterized in that the magnetic ring system is adjustable to the electron-optical axis.

3460

Claims (5)

    ';., Erf indu'nÄsanspruch
  1. Anspruch [en] A device for deflecting positive ions on an electron gun to protect the cathode from ion bombardment, characterized in that. Cathode is surrounded by a magnet system and there is a rotationally symmetrical PeId to the electron-optical axis, which diverges from the cathode to the anode of the electron gun.
  2. 2 · Device according to item 1, characterized in that the magnet system consists of two permanent magnet rings, which are surrounded by a ring-shaped magnetic yoke and between which there is a variable air gap.
  3. Device according to item 1, characterized in that the magnetizing system consists of an axially magnetized permanent magnet ring arranged in an annular pole piece.
  4. 4 · Device according to item 1, characterized in that the rotationally symmetrical PED is generated by the magnet system of an atomizer pump integrated in the electron gun.
  5. 5. The device according to item 1, characterized in that the magnetic ring system is adjustable to the electron-optical axis. ,
    3460
DD21316279A 1979-05-28 1979-05-28 Protection of a catode in electron beam instruments DD143187A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DD21316279A DD143187A1 (en) 1979-05-28 1979-05-28 Protection of a catode in electron beam instruments

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DD21316279A DD143187A1 (en) 1979-05-28 1979-05-28 Protection of a catode in electron beam instruments
GB8017043A GB2052847B (en) 1979-05-28 1980-05-23 Protection of the cathode of an electron beam tube from ion bombardment
DE19803019684 DE3019684A1 (en) 1979-05-28 1980-05-23 Protective device of a catode in electron radiators
JP7023480A JPS6019620B2 (en) 1979-05-28 1980-05-28

Publications (1)

Publication Number Publication Date
DD143187A1 true DD143187A1 (en) 1980-08-06

Family

ID=5518347

Family Applications (1)

Application Number Title Priority Date Filing Date
DD21316279A DD143187A1 (en) 1979-05-28 1979-05-28 Protection of a catode in electron beam instruments

Country Status (4)

Country Link
JP (1) JPS6019620B2 (en)
DD (1) DD143187A1 (en)
DE (1) DE3019684A1 (en)
GB (1) GB2052847B (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8600098A (en) * 1986-01-20 1987-08-17 Philips Nv Cathode jet tube with ion trap.
DE4430534A1 (en) * 1994-08-27 1996-04-11 Hell Ag Linotype Electron beam generator
KR100447659B1 (en) * 2002-10-24 2004-09-07 엘지.필립스디스플레이(주) A Electron Gun for Color CRT
US8129910B2 (en) * 2009-06-23 2012-03-06 L-3 Communications Corporation Magnetically insulated cold-cathode electron gun

Also Published As

Publication number Publication date
GB2052847A (en) 1981-01-28
JPS55161327A (en) 1980-12-15
JPS6019620B2 (en) 1985-05-17
GB2052847B (en) 1983-01-12
DE3019684A1 (en) 1980-12-04

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