US3283120A - Apparatus for working materials with a beam of charged particles - Google Patents

Apparatus for working materials with a beam of charged particles Download PDF

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Publication number
US3283120A
US3283120A US353324A US35332464A US3283120A US 3283120 A US3283120 A US 3283120A US 353324 A US353324 A US 353324A US 35332464 A US35332464 A US 35332464A US 3283120 A US3283120 A US 3283120A
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United States
Prior art keywords
lens
focusing
workpiece
current
working
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 - Lifetime
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US353324A
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English (en)
Inventor
Spruck Helmut
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Raytheon Technologies Corp
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United Aircraft Corp
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Publication date
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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
    • H01J37/02—Details
    • H01J37/21—Means for adjusting the focus
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K15/00—Electron-beam welding or cutting
    • B23K15/0013—Positioning or observing workpieces, e.g. with respect to the impact; Aligning, aiming or focusing electronbeams
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B17/00—Details of cameras or camera bodies; Accessories therefor
    • G03B17/02—Bodies
    • G03B17/12—Bodies with means for supporting objectives, supplementary lenses, filters, masks, or turrets
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B7/00—Control of exposure by setting shutters, diaphragms or filters, separately or conjointly
    • G03B7/08—Control effected solely on the basis of the response, to the intensity of the light received by the camera, of a built-in light-sensitive device
    • G03B7/099—Arrangement of photoelectric elements in or on the camera
    • G03B7/0993—Arrangement of photoelectric elements in or on the camera in the camera

Definitions

  • This invention relates to working a material with a beam of charged particles, and particularly to performing operations such as welding, cutting, melting, evaporating, or machining on any material with an electron beam.
  • the beam of charged particles is focused by means of an electromagnetic lens on the workpiece to be treated.
  • the current which flows through the focusing lens is adjusted manually while the area of the workpiece on which the electron beam impinges is being watched through an observation device.
  • the lens current which flows through the focusing coil is usually so adjusted that th impingement point of the electron beam has its narrowest cross-section on the surface of the workpiece.
  • the present invention relates to a process for treating a workpiece by means of a beam of charged particles focused on the workpiece by an electromagnetic lens and is characterized particularly in that the proper focusing of the electron beam is constantly maintained independently of changes in machine adjustments and working distance.
  • the present invention is based on the observation that during the Working of the materials by means of an electron beam first the accelerating voltage, the beam current and the working speed are set, and that during the course of the working operation in most instances only the working distance. will change. According to the new Patented Nov.
  • the device for generating the current flowing through the focusing lens is influenced in such a manner that it supplies a lens current set to the proper value, that is to say, when the operation begins the electron beam is focused on the surface of the workpiece. If during the working operation a change of the working distance occurs, this change is registered constantly and simultaneously the current flowing through the focusing lens is constantly re-adjusted in such a way that the proper focusing of the beam is maintained.
  • An optical measurement of the Working distance presupposes that the electron beam is in operation and that accordingly its impingement point is brightly illuminated with respect to the dark surrounding area.
  • the adjustment of the working distance before the start of the working operation is obtained by an adjustment to the approximate value, this value being obtained from the known distance between the workpiece support and the lower edge of the lens and the thickness of the workpiece.
  • the lens current supply device is automatically so influenced that the focusing of the beam is correctly adjusted.
  • tungsten strip at the level of the workpiece surface, to operate the beam and to measure the bright spot produced on the strip. In this manner the focusing of the electron beam which is correct for the measured working distance is assured. After disconnecting the beam the tungsten strip may be re placed by the workpiece and thus the beam is focused correctly on the workpiece surface at the beginning of the working operation.
  • the arrangement according to the invention consists of a known apparatus for working materials by means of an electron beam which is provided with an electromagnetic lens for focusing the electron beam.
  • a lens current supply device is provided for the purpose of supplying current to the focusing lens.
  • Means for determining the magnitude of the lens current are connected to means for adjusting the accelerating voltage and the beam current.
  • an optical distance meter for measuring the working distance is provided, this distance meter being also connected to the lens current determining device.
  • a control member is connected to the lens current supply device for the purpose of adjusting the axial position of the focusing point.
  • the axial position of the focusing point may be displaced as desired without influencing the remaining automatic adjustment of the focusing point in any manner.
  • the optical distance meter is preferably so designed that it measures the bright spot produced by the electron beam on the workpiece and generates in the plane of a photocell two pictures of this spot which coincide to form a double image upon reaching the balanced state.
  • tWo photocells are provided Whose separation line coincides with the center line of the double image.
  • FIGURE 1 shows diagrammatically an embodiment of the apparatus according to the invention.
  • FIGURE 2 shows diagrammatically an embodiment of the lens current supply device incorporated in FIGURE 1.
  • FIGURE 3 shows a partial section of another embodiment of the apparatus according to the invention.
  • FIGURE 1 The apparatus for working materials by means of an electron beam illustrated in FIGURE 1 shows the cathode 1, the control cylinder 2 and the grounded anode 3 of the beam generating system.
  • device 4 a high voltage of about 100 kv. is generated and supplied by means of a high voltage cable to device 5.
  • This device is adapted to produce the adjustable heating voltage and the adjustable control cylinder bias voltage. These voltages are conducted over a high voltage cable to the beam generator system 1, 2, 3.
  • a control member 6 is connected to device 4 and is adapted to adjust the value of the high voltage.
  • Another control member 7 is connected to device and is adapted to adjust the control cylinder bias voltage and thus the adjustment of the beam current.
  • a magnetic deflecting system 8 which is adapted to adjust the electron beam 10.
  • Deflection voltage generator 9 feeds current to the deflecting system 8.
  • a screen 11 is mounted which may be moved by means of knobs 12 and 13 in the plane of the drawing and also perpendicularly to the plane of the drawing. After the adjustment of the electron beam it passes through the screen 11 and is focused by means of the electromagnetic lens 14 on the workpiece 16 arranged in the work chamber 15.
  • An electromagnetic deflecting system 17 arranged be low the focusing lens 14 is supplied with current from lens current generator 18 and is adapted to deflect the electron beam 10 relative to the workpiece 16.
  • the workpiece 16 is placed in work chamber on a cross-table 19 which may be moved by means of hand wheels 20 and 21 in the plane of the drawing and perpendicularly to the plane of the drawing.
  • hand wheels 20 and 21 electric motors may be provided which carry out the movement of the workpiece 16.
  • an optical lens 22 is mounted which is movable in the direction of its optical axis. This lens is provided with a bore into which a tube 23 is placed. Electron beam 10 passes through this tube 23.
  • the lens 22 is moved in the axial direction by means of an electric motor 24 and a drive 25.
  • a mirror 26 is mounted which has an opening allowing the passing of the electron beam 10.
  • the electron beam 19 generates on the surface of the workpiece 16 a brightly illuminated spot. The light emitted from this spot passes through lens 22 and is projected over the mirror 26 to a pair of photocells 27 and 28.
  • an additional lens 29 is mounted which produces in the balanced state a coinciding double image of the illuminated spot on the workpiece 16 in the plane of the photocells 27, 28.
  • a filter element 30 is mounted in a beam portion of the light reflected by mirror 26 .
  • a bridge connection 31 is provided which is connected to the electric motor 24.
  • the electric motor 24 provides the axial displacement of the lens 22 and also the actuation of the control member 32.
  • control member 32 and the two control members 6 and 7 are connected to a lens current supply device 33.
  • This device furnishes the current flowing through the focusing lens 14.
  • Additional control member 34 is connected to the lens current supply device 33 and is adapted to adjust the axial position of the focusing point of the electron beam 10.
  • the lens current supply device 33 is illustrated diagrammatically in FIGURE 2. It consists essentially of the potentiometers 35, 36 and 37 and of the battery or power supply 38. To adjust the lens current the sliders 39, and 41 are moved. It is also possible .to rotate the potentiometer 37 relative to its slider 41 and this is irzme by means of the control knob 34 via driving gears.
  • the operation of the apparatus is as follows: Before starting the working operation and based on the properties of the workpiece the accelerating voltage is set by means of control 6 and the beam current by means of bias voltage control 7. By means of control 6 the slider 39 and by means of control 7 the slider 40 are moved in the lens current supply device 33. The work distance is thereafter set by means of control 32 whereby slider 41 is moved.
  • the controls 6, 7, 32 and 34 co-operate with dials not shown in the drawing. After controls 6, 7 and 32 are set such a resistance value is established across potentiometers 35, 36 and 37 that the lens current supplied from source 33 to focusing lens 14 produces a focusing of the electron beam 10 on the surface of the workpiece 16.
  • the optical arrangements 22, 26, 29 produces in the plane of the photocells 27, 28 no coinciding double image of the illuminated spot on the workpiece 16.
  • the two images deviate from the center by opposite equal amounts.
  • filter 30 it is obtained that one of the photocells 27, 28 receives less light than the other cell. Due to this, the bridge 31 becomes unbalanced and the electric motor 24 receives current.
  • This movement of the lens 22 is simultaneously transferred over control 32 into the lens current supply device 33.
  • the slider 41 on potentiometer 37 is thereby displaced and the current through focusing lens 14 is varied in a direction which refocuses the electron beam at the surface of the workpiece 16 in spite of the changed working distance.
  • an optical distance meter is arranged in the work chamber 15 below the focusing lens 14.
  • This distance meter consists of mirrors 50 and 52 and lenses 54 and 56. is designed to be semi-transparent.
  • the distance meter is so .set that it produces, in the balanced position, in the plane of two photocells 58, 60 a coinciding double image of the illuminated spot on the workpiece 16. If the working distance changes a coinciding double image is no longer created in the plane of the cells 58, 6t) and the two partial images deviate from each other. Due to this, one of the two photocells 58, 60 receives more current than the other cell and the associated bridge connection 62 starts to operate. Over this bridge connection the electric motor 64 receives current and this motor rotates over the flexible shaft 66 the mirror 52 until in the plane of the photocells 58, 60 again a coinciding double image is obtained.
  • the control 32 of the lens current supply device 33 is actuated.
  • the electron beam may impinge continuously on the workpiece 16.
  • the present invention is particularly suitable for application in apparatus for milling, cutting, soldering or welding by means of an electron beam. In all these cases the workpiece is moved continuously relative to the electron beam so that upon a change in the working distance a continuous readjustment of the focusing action is necessary.
  • the present invention finds also appropriate application in apparatus for drilling by means of an electron beam. If in such applications several holes are to be drilled in a workpiece at different locations it is not necessary to re-adjust manually the focusing action between the diiferent holes because also in this case an automatic re-adjustment takes place.
  • Apparatus for working material with an energized beam comprising:
  • said means for generating an energized beam comprises:
  • the mirror 52 means for accelerating the charged particles from said source toward a material to be worked, means for forming said accelerated particles into a beam, and means for controlling the beam current.
  • said focusing means comprises:
  • an adjustable lens current supply and means responsive to said signal indicative of a variation in working distance for varying the current flowing from said supply through said electromagnetic lens.
  • means coupling said particle accelerating and beam current controlling means to said lens current supply whereby adjustment of the beam current or particle acceleration varies the lens current.
  • said optical working distance measuring means comprises:
  • sensing means for sensing the illuminated spot produced on the material being worked by the beam and for producing two images thereof, and light sensitive means responsive to the images produced by said sensing means for generating an electrical signal indicative of a variation in working distance when said images do not coincide.
  • optical system having a variable focal length, means responsive to the signal generated by said light sensitive means for varying the focus of said optical system, and an optical filter positioned between said optical system and said sensing means for attenuating one of said images.
  • said light sensitive means comprises:

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Welding Or Cutting Using Electron Beams (AREA)
  • General Induction Heating (AREA)
US353324A 1963-03-23 1964-03-20 Apparatus for working materials with a beam of charged particles Expired - Lifetime US3283120A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEZ10000A DE1225775B (de) 1963-03-23 1963-03-23 Verfahren und Einrichtung zur Bearbeitung eines Werkstueckes mittels eines Ladungstraegerstrahles

Publications (1)

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US3283120A true US3283120A (en) 1966-11-01

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US353324A Expired - Lifetime US3283120A (en) 1963-03-23 1964-03-20 Apparatus for working materials with a beam of charged particles

Country Status (8)

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US (1) US3283120A (xx)
BE (1) BE645421A (xx)
CH (1) CH419370A (xx)
DE (1) DE1225775B (xx)
FR (1) FR1388356A (xx)
GB (1) GB1044056A (xx)
NL (1) NL6403042A (xx)
NO (1) NO119619B (xx)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3444351A (en) * 1965-06-11 1969-05-13 Siemens Ag Method and apparatus for welding and checking tubular workpieces
US3465119A (en) * 1967-06-21 1969-09-02 United Aircraft Corp Multiaxis optical viewing system of a movable electron beam in a vacuum chamber
US3471703A (en) * 1965-08-28 1969-10-07 Ferranti Ltd Photoelectric control means for the deflection of the electron beam in welding apparatus
US3535488A (en) * 1967-07-13 1970-10-20 Rohr Corp Tracer beam method of proofing electron beam weld path
US3575433A (en) * 1968-01-20 1971-04-20 Goetzewerke Piston ring for an internal-combustion engine and method for making same
US3601575A (en) * 1964-07-24 1971-08-24 Steigerwald Gmbh K H Method and apparatus for viewing the impact spot of a charge carrier beam
US3761676A (en) * 1971-05-20 1973-09-25 Farland G Mc Portable electron beam welding apparatus
US3895254A (en) * 1973-07-02 1975-07-15 Hitachi Ltd Charged particle accelerator with integral transformer and shielding means
US4074104A (en) * 1974-12-19 1978-02-14 General Electric Company Opto-electronic position sensing method
US4189641A (en) * 1976-09-03 1980-02-19 Hitachi, Ltd. Electron microscope
US4210806A (en) * 1979-01-18 1980-07-01 International Business Machines Corporation High brightness electron probe beam and method
US4310764A (en) * 1979-06-12 1982-01-12 Fujitsu Limited Electron beam irradiation apparatus
US4633611A (en) * 1984-12-31 1987-01-06 Bakish Materials Corporation Process and apparatus for disinfecting seeds
US5185530A (en) * 1990-11-05 1993-02-09 Jeol Ltd. Electron beam instrument
US6745717B2 (en) * 2000-06-22 2004-06-08 Arizona Board Of Regents Method and apparatus for preparing nitride semiconductor surfaces

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2304814A (en) * 1941-03-20 1942-12-15 Charles J Glasser Optical testing device and method of testing
US2472951A (en) * 1946-09-10 1949-06-14 Air Reduction Method and apparatus for controlling torch spacing
US2945132A (en) * 1957-03-18 1960-07-12 Zeiss Jena Veb Carl Measuring apparatus having optical and photoelectric means
US3037423A (en) * 1957-12-30 1962-06-05 Polaroid Corp Automatic focusing system
US3158733A (en) * 1962-09-12 1964-11-24 Nat Res Corp Focus control for electron beam heating

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1100835B (de) * 1952-03-01 1961-03-02 Zeiss Carl Fa Einrichtung zum Fraesen von Profilen, zum Schneiden von Schablonen oder zum Bohren von Duesenkanaelen mittels eines Ladungstraegerstrahles
NL248568A (xx) * 1959-02-20

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2304814A (en) * 1941-03-20 1942-12-15 Charles J Glasser Optical testing device and method of testing
US2472951A (en) * 1946-09-10 1949-06-14 Air Reduction Method and apparatus for controlling torch spacing
US2945132A (en) * 1957-03-18 1960-07-12 Zeiss Jena Veb Carl Measuring apparatus having optical and photoelectric means
US3037423A (en) * 1957-12-30 1962-06-05 Polaroid Corp Automatic focusing system
US3158733A (en) * 1962-09-12 1964-11-24 Nat Res Corp Focus control for electron beam heating

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3601575A (en) * 1964-07-24 1971-08-24 Steigerwald Gmbh K H Method and apparatus for viewing the impact spot of a charge carrier beam
US3444351A (en) * 1965-06-11 1969-05-13 Siemens Ag Method and apparatus for welding and checking tubular workpieces
US3471703A (en) * 1965-08-28 1969-10-07 Ferranti Ltd Photoelectric control means for the deflection of the electron beam in welding apparatus
US3465119A (en) * 1967-06-21 1969-09-02 United Aircraft Corp Multiaxis optical viewing system of a movable electron beam in a vacuum chamber
US3535488A (en) * 1967-07-13 1970-10-20 Rohr Corp Tracer beam method of proofing electron beam weld path
US3575433A (en) * 1968-01-20 1971-04-20 Goetzewerke Piston ring for an internal-combustion engine and method for making same
US3761676A (en) * 1971-05-20 1973-09-25 Farland G Mc Portable electron beam welding apparatus
US3895254A (en) * 1973-07-02 1975-07-15 Hitachi Ltd Charged particle accelerator with integral transformer and shielding means
US4074104A (en) * 1974-12-19 1978-02-14 General Electric Company Opto-electronic position sensing method
US4189641A (en) * 1976-09-03 1980-02-19 Hitachi, Ltd. Electron microscope
US4210806A (en) * 1979-01-18 1980-07-01 International Business Machines Corporation High brightness electron probe beam and method
US4310764A (en) * 1979-06-12 1982-01-12 Fujitsu Limited Electron beam irradiation apparatus
US4633611A (en) * 1984-12-31 1987-01-06 Bakish Materials Corporation Process and apparatus for disinfecting seeds
US5185530A (en) * 1990-11-05 1993-02-09 Jeol Ltd. Electron beam instrument
US6745717B2 (en) * 2000-06-22 2004-06-08 Arizona Board Of Regents Method and apparatus for preparing nitride semiconductor surfaces

Also Published As

Publication number Publication date
BE645421A (xx) 1964-07-16
DE1225775B (de) 1966-09-29
GB1044056A (en) 1966-09-28
NL6403042A (xx) 1964-09-24
FR1388356A (fr) 1965-02-05
CH419370A (fr) 1966-08-31
NO119619B (xx) 1970-06-08

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