JP5095540B2 - Electron gun and electron beam generator - Google Patents

Description

  The present invention relates to an electron gun and an electron beam generator that generate and emit an electron beam, and more particularly to an electron gun and an electron beam generator that can emit an electron beam in a direction that can be easily focused from a cathode near a filament.

  The electron gun is a device that emits thermoelectrons by heating a filament, and radiates the emitted thermoelectrons as an electron beam by accelerating the cathode and the anode (see Patent Document 1). FIG. 1 shows a schematic configuration diagram of an electron beam generator using this electron gun. FIG. 2 shows a schematic configuration of the electron emission portion of the electron gun 10 used in the electron beam generator 1. 2A is a plan view, and FIG. 2B is a side view as viewed from the direction of the arrow Y1 shown in FIG.

  The electron gun 10 is disposed between the upper cathode 12a and the lower cathode 12b, and the upper cathode 12a and the lower cathode 12b, which are vertically formed by forming a concave groove parallel to the bottom surface inside the cathode 12. The filament 14 is provided, and the upper cathode 12a and the anode 15 disposed at a predetermined interval from the upper cathode 12a to the electron beam e1 radiation direction.

  As shown in FIG. 1, a high voltage power supply 16 that applies a high voltage is connected between the cathode 12 and the anode 15, and a filament power supply 17 that supplies current to the filament 14 is connected to the filament 14. . Further, a magnetic field generating device that generates a magnetic field 18 described later is disposed on the side of the opening 19 where the electron beam e1 is emitted from the electron gun 10 to the outside. FIG. 1 shows a crucible 21 containing a vapor deposition material 20 disposed in a vapor deposition apparatus (not shown).

  In such a configuration, it is assumed that a high voltage is applied between the cathode 12 and the anode 15 by the high voltage power supply 16 and a predetermined current is passed through the filament 14 by the filament power supply 17. In this case, the filament 14 is heated to emit thermoelectrons, and the thermoelectrons are accelerated between the upper and lower cathodes 12a and 12b and the anode 15, and this is an opening 19 provided on the anode 15 side as an electron beam e1. To the outside of the electron gun 10.

  The emitted electron beam e1 is deflected so as to be focused and irradiated on the vapor deposition material 20 as a target by the magnetic field 18 generated by the magnetic field generator. When the vapor deposition material 20 is irradiated with the electron beam e1, the vapor deposition material 20 melts and evaporates, and a film is formed on the surface of the deposition object (not shown).

JP 2007-165160 A

  As described above, as shown in FIG. 2, the electron beam e1 from the filament 14 is emitted in the diffusion direction from the upper and lower cathodes 12a and 12b, and between the upper and lower cathodes 12a and 12b and the anode 15. It is accelerated and emitted from the opening 19 to the outside. As described above, since the electron beam e1 is spread and emitted, there is a problem that the focusing of the electron beam e1 is poor or adjustment for focusing is very difficult.

  Further, the electron beam e1 radiated and spread must be properly focused while being bent to the position of the vapor deposition material 20. In order to focus the electron beam e1 satisfactorily, a magnetic field generation device that generates a magnetic field 18 in which many components such as a magnetic material are appropriately adjusted and combined is necessary, which causes a problem that the device cost increases. .

  In order to solve the above-mentioned problems, the present invention improves the focusing of the electron beam emitted from the electron gun at the electrode section, obtains a beam with good focusing characteristics, and reduces the number of components of the focusing magnetic field generator. The purpose is to reduce the cost of the equipment.

  In order to achieve the above object, a cathode having an opening and a space having an arc-shaped side surface inside, and a groove formed in the arc-shaped side surface in the space along the circumferential direction, and the groove An electron gun having a filament that is disposed inside and emits electrons when heated, and an anode that accelerates electrons emitted from the filament between the cathode and the cathode. An upper cathode and a lower cathode formed in a circular arc shape with the upper and lower sides sandwiched, and the radius of curvature of the arc side of the upper cathode is different from the radius of curvature of the arc side of the lower cathode. A featured electron gun was used.

  According to this configuration, the shape of the electron beam radiation surface formed by the arc sides of both the upper and lower cathodes is formed in the shape of a concave lens that collects light, so that the thermoelectrons emitted from the filament are It is accelerated toward the focusing direction by the lens effect of the radiation surface. The accelerated electrons are emitted as an electron beam from the electron gun in a focused state at the aperture. This emitted electron beam is focused at the aperture. Therefore, the focusing characteristics of the electron beam can be improved.

  It is desirable that the electron gun of the present invention further includes a columnar protrusion that is erected in the space of the cathode in a state where the tip is disposed in the vicinity of the opening of the cathode.

  According to this configuration, when an electron beam is emitted from the electron gun, positive ions are generated around the electron beam and attracted to the cathode side from the opening. Therefore, the positive ions collide with the tip and are absorbed by the protrusion. Therefore, it is possible to prevent the positive ions attracted to the cathode side from colliding with the filament and degrading the filament.

  In the electron gun of the present invention, it is preferable that the radius of curvature of the arc sides of both the upper cathode and the lower cathode is set to a dimension that allows the accelerated electrons to be focused at the opening.

  According to this configuration, the shape of the electron emission side of the upper and lower cathodes can be a concave lens that is optimal for bringing the electrons into a predetermined condensing state, so that the electron beam emitted from the electron gun The focusing characteristic can be further improved.

  In the electron gun of the present invention, it is desirable that a part of the upper cathode is interposed so as to intersect a virtual straight line connecting the anode and the filament.

  According to this configuration, when thermionic electrons are emitted from the filament, a part of the upper cathode is interposed in a virtual straight line connecting the filament and the anode, so that the electrons generated from the filament do not directly collide with the anode. .

  In the electron gun of the present invention, it is desirable that the filament is linear.

  According to this configuration, even if the filament is linear, the thermoelectrons emitted from the filament are accelerated toward the focusing direction by the lens effect described above and are emitted from the electron gun as an electron beam. The focusing characteristic does not decrease below a predetermined level. Accordingly, since the shape of the filament can be simplified, the filament can be manufactured at a low cost accordingly.

  More specifically, the electron beam generator includes any one of the above-described electron guns and a magnetic field generator that deflects and focuses an electron beam emitted from the electron gun.

  According to this configuration, since the electron beam emitted from the electron gun is focused at the opening, the magnetic field generator is focused while deflecting the electron beam with a simpler configuration and easier adjustment than in the past. The target can be irradiated. Accordingly, since the configuration of the magnetic field generation device can be simplified as compared with the conventional case, the manufacturing cost of the electron beam generation device can be reduced accordingly.

  According to the present invention, an electron gun and an electron beam generating apparatus capable of improving the focusing characteristics of an electron beam emitted from an electron gun and reducing the number of parts of a focusing magnetic field generating apparatus to reduce the apparatus cost. Can be provided.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In the present specification and drawings, the same reference numerals denote the same components.

  FIG. 3 shows a configuration of the electron gun 30 according to the embodiment of the present invention, and FIG. 3A is a cross-sectional perspective view in a state in which one of the two side plates 32a and 32b of the cathode 32 of the electron gun 30 is removed. , (B) is a plan view.

  The electron gun 30 includes a cathode 32 having a space inside, an arc-shaped solenoid-like filament 34 disposed in a concave groove 32 c described later provided inside the cathode 32, and a cathode 32. A substantially fan-shaped anode 36 disposed and a columnar protrusion 38 erected in contact with the fan-shaped essential position V1 of the cathode 32 are provided. In addition, although the cathode 32 and the anode 36 are formed with a metal, the metal excellent in workability and durability at high temperature is used suitably. When the electron beam e radiated from the electron gun 30 is deflected by a magnetic field, the magnetic material is affected by the magnetic field, so it is preferable to use a non-magnetic metal.

  More specifically, the cathode 32 is arranged in a fan shape with a fan-shaped bottom plate 32d having V1 as a required position and one side of the bottom plate 32d perpendicular to the bottom surface of the bottom plate 32d along both sides of the bottom plate 32d. In addition, two side plates 32a and 32b and an arc-shaped side plate (hereinafter referred to as an arc-shaped side plate) 32e that joins the separated vertical other sides of the side plates 32a and 32b are provided. However, in the present embodiment, the cathode 32 has a structure having the bottom plate 32d, but may have a structure without the bottom plate 32d.

  Further, a concave groove 32c is formed inside the arc-shaped side plate 32e in parallel with the bottom surface of the bottom plate 32d along the circumferential direction of the arc, and inside the two side plates 32a and 32b and the anode 36 disposed above. A region surrounded by the arc-shaped side (hereinafter referred to as the inner arc side) is an opening 40 that radiates the electron beam e to the outside.

  In the vicinity of the opening 40, a projecting portion 38 is disposed on the bottom surface where the tip end portion 38a is disposed. The protrusion 38 has a shape in which a cylinder is divided at a fan-shaped angle, and an inclined inclined portion 38b that gradually narrows upward is formed on the side surface facing the filament 34, and is formed at the upper end of the inclined portion 38b. It has a shape in which an elongated rod-like tip portion 38a is erected. The protrusion 38 prevents positive ions from being generated around the electron beam e when the electron beam e is radiated and attracted to the cathode 32, colliding with the filament 34, and being disconnected. However, the alternate long and short dash line H1 is a central axis that divides the electron gun 30 having a fan-shaped plane shape symmetrically through the fan-shaped essential position V1, and is a straight line parallel to the bottom surface of the bottom plate 32d. Further, as described above, in the case of the structure without the bottom plate 32d, the protrusion 38 is fixed only by the side plates 32a and 32b. Or you may fix by another support method. Further, the protrusion 38 may have a shape such as a cylinder or a rectangular parallelepiped, in addition to a shape in which a cylinder is divided by a fan-shaped angle. Further, although the electron gun 30 has a fan shape in this example, the electron gun 30 is not necessarily a fan shape, but may have another plane shape as long as the cathode 32 includes an arcuate side plate 32e having a groove 32c. Good.

  The first feature of the present embodiment is that, as shown in FIG. 4A, the curvature radius R1 of the inner arc side of the upper cathode 32f formed above and below the concave groove 32c of the cathode 32, and the lower This is that the size of the inner arc side of the side cathode 32g and the radius of curvature R2 is formed so as to satisfy the relationship of R1> R2. However, the relationship of R1 <R2 may be sufficient. Further, the radius of curvature R3 of the inner arc side of the anode 36 is preferably the same as or smaller than the radius of curvature R2. For example, it is formed in a size of R1 = 15 mm, R2 = 12 mm, and R3 = 12 mm. However, in the present embodiment, the center axes of the arc sides of the upper cathode 32f and the lower cathode 32g are aligned vertically, but they do not necessarily have to be aligned.

  The second feature is that when the filament 34 is disposed in the concave groove 32c, it passes through the central axis of the inner arc side of the upper cathode 32f as shown in the cross-sectional view of FIG. 4B or 4C. The filament 34 does not protrude from the vertical line V2 perpendicular to the bottom surface to the opening 40 side. However, the inner arc side of the lower cathode 32g has a shape in which the inner arc side of the upper cathode 32f and the central axis coincide vertically as shown in FIG. 4B, and as shown in FIG. 4C. Any of the shapes positioned on the deeper side of the groove 32c than the upper cathode 32f may be used. That is, in other words, it is only necessary that a part of the upper cathode 32 f intersects a virtual straight line connecting the anode 36 and the filament 34.

  FIG. 5 shows a configuration of an electron beam generator using the electron gun 30 having such a configuration. The electron beam generator 41 includes a high voltage power source 42 connected between the anode 36 and the cathode 32 of the electron gun 30, a filament power source 43 connected to the filament 34, and a magnetic field that generates a magnetic field 44 near the orbit of the electron beam e. A generation device is provided and configured. FIG. 5 shows a crucible 21 containing a vapor deposition material 20 arranged in a vapor deposition apparatus (not shown).

  In such a configuration, when a high voltage is applied between the cathode 32 and the anode 36 by the high voltage power source 42 and a predetermined current flows through the filament 34 by the filament power source 43, the filament 34 is heated and thermoelectrons are emitted. The thermoelectrons are accelerated between the upper and lower cathodes 32 f and 32 g and the anode 36, and are emitted as an electron beam e from the opening 40 to the outside of the electron gun 30.

  At this time, the shape of the emission surface of the electron beam e (referred to as an electron beam emission surface) by the inner arc sides of both the upper and lower cathodes 32f and 32g is formed as a concave lens that collects light. For this reason, as shown in FIG. 6, the thermoelectrons emitted from the filament 34 are accelerated as an electron beam e toward the focusing direction by the lens effect of the electron beam radiation surface by the upper and lower cathodes 32f and 32g. The accelerated electron beam e is emitted from the opening 40 as shown in FIG. 5 in a focused state at the opening.

  Further, the electron beam e emitted from the aperture 40 in a focused state at the aperture is deflected so as to be focused and irradiated onto the vapor deposition material 20 as a target by a magnetic field generating device that generates a magnetic field 44. When the vapor deposition material 20 is irradiated with the electron beam e, the vapor deposition material 20 is melted and evaporated, and a film is formed on the surface of the deposition target (not shown).

  Further, when the electron beam e is radiated from the opening 40, positive ions are generated around the electron beam e and attracted to the cathode 32 side from the opening 40. The tip 40a of the protrusion 38 is disposed in the opening 40. Therefore, the positive ions collide with the tip portion 38 a and are absorbed by the projection 38. Accordingly, positive ions attracted to the cathode 32 do not collide with the filament 34. However, the electron gun 30 of the present embodiment may be configured without the protrusion 38.

  As described above, the electron gun 30 of the present embodiment has the space having the opening 40 and the arc-shaped side surface inside, and the groove 32c is formed along the circumferential direction on the arc-shaped side surface in the space. A box-like cathode 32, a filament 34 that is disposed in the concave groove 32c and emits electrons when heated by energization, and an anode 36 that accelerates electrons emitted from the filament 34 to and from the cathode 32. The configuration has the following characteristics.

  That is, the upper cathode 32f and the lower cathode 32g, which are formed in a circular arc shape with the concave groove 32c interposed therebetween, have a radius of curvature R1 of the arc side of the upper cathode 32f and a radius of curvature R2 of the arc side of the lower cathode 32g. Formed differently.

  With this configuration, the shape of the electron beam radiation side of the upper and lower cathodes 32g is formed in an arc shape, in other words, a concave lens shape for condensing light, so that the thermoelectrons emitted from the filament 34 are The lens is accelerated toward the focusing direction by the lens effect of the electron beam emitting surfaces of the upper and lower cathodes 32g. The accelerated electrons are emitted from the opening 40 in a focused state at the opening and are emitted from the electron gun 30 as an electron beam. This emitted electron beam is focused at the aperture. Therefore, it is easy to focus the electron beam in the entire system, and the focusing characteristics can be improved.

  It is desirable that the radii of curvature R1 and R2 of the arc sides of both the upper and lower cathodes 32f and 32g have dimensions that allow the accelerated electrons to converge at the aperture. With this configuration, the shape of the electron beam radiation surface formed by the upper and lower cathodes 32f and 32g can be a concave lens shape that is optimal for bringing electrons into a predetermined condensing state. Therefore, the electron beam emitted from the electron gun Can be further improved.

  In addition, a magnetic field generation device that generates a magnetic field 44 that combines with the electron gun 30 and performs a process of deflecting and converging the electron beam emitted from the electron gun 30 has a simpler configuration and easier adjustment than the conventional one. Can be focused while deflecting. Therefore, since the magnetic field generation device can be configured in a simplified manner as compared with the conventional case, the adjustment of components for obtaining good focusing can be reduced, and as a result, the manufacturing cost can be reduced. Therefore, the manufacturing cost of the electron beam generator 41 configured to include the electron gun 30 and the magnetic field generator can be reduced.

  Further, when thermionic electrons are emitted from the filament 34, a part of the upper cathode 32f intersects with an imaginary straight line connecting the filament 34 and the anode 36. With this configuration, when thermionic electrons are emitted from the filament 34, the upper cathode 32f intersects the imaginary straight line connecting the filament 34 and the anode 36, so that the electrons from the filament 34 directly collide with the anode 36. Things will disappear.

  Further, as shown in FIG. 7, even if the filament 34-1 is linearly disposed in the concave groove 32c, the thermoelectrons emitted from the filament 34-1 are directed toward the focusing direction by the lens effect described above. It is accelerated and emitted as an electron beam e. In this way, when the filament 34-1 is linear, the shape of the filament 34-1 can be simplified, and accordingly, the filament 34-1 can be manufactured at low cost.

  The electron gun and electron beam generator of the present invention are widely used as evaporation sources for vacuum deposition apparatuses for coating such as digital cameras, glasses, projector lenses, DVDs, CD detection lenses, plasma displays, digital video tapes, etc. It can also be applied to optical communication, solar energy application fields, copying machines, and the like.

It is a schematic block diagram of the electron beam generator using the conventional electron gun. The schematic structure of the electron emission part of the conventional electron gun is shown, (a) is a top view, (b) is the side view seen from the arrow Y1 direction shown to (a). The structure of the electron gun by embodiment of this invention is shown, (a) is a cross-sectional perspective view in the state which removed one side plate among the two side plates of the cathode of an electron gun, (b) is a top view. (A) is a top view which shows the curvature radius of each inner side arc side of the upper cathode of the electron gun of this embodiment, a lower cathode, and an anode, (b) is an inner side arc side of the upper side and lower cathode of (a). (C) is a cross-sectional view when the inner arc side of the lower cathode of (a) is arranged deeper than the inner arc side of the upper cathode. It is a schematic block diagram of the electron beam generator using the electron gun of this embodiment. It is a top view for demonstrating the lens effect of the electron gun of this embodiment. It is a top view which shows the filament of the other structure in the electron gun of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,41: Electron beam generator 10, 30: Electron gun 12, 32: Cathode 12a, 32f: Upper cathode 12b, 32g: Lower cathode 14, 34, 34-1: Filament 15, 36: Anode 16, 42: High-voltage power supply 17, 43: Filament power supply 19, 40: Opening 20: Vapor deposition material 21: Crucible 32a, 32b: Side plate 32c of cathode: Groove 32d: Bottom plate 34: Filament 32e: Arc-shaped side plate 38 of cathode: Projection 38a : Tip portion 38b: inclined portion 18, 44: generated magnetic field e, e1: electron beam R1: radius of curvature of inner arc side of upper cathode R2: radius of curvature of inner arc side of lower cathode R3: radius of curvature R3 of anode Curvature radius of inner arc side

Claims (6)

A cathode having an opening and having an arc-shaped side surface in the interior, the arc-shaped side surface in which the groove is formed along the circumferential direction, and a cathode disposed in the groove and heated. In an electron gun having a filament that emits electrons and an anode that accelerates electrons emitted from the filament to the cathode,
The cathode includes an upper cathode and a lower cathode that are formed in an arc shape up and down across the concave groove, and the radius of curvature of the arc side of the upper cathode is different from the radius of curvature of the arc side of the lower cathode. An electron gun characterized by being formed as follows. The electron gun of claim 1 wherein said upper cathode and the curvature radius of the arc sides of both the lower cathodes, said accelerated the electrons are sized to a focusing state at the opening. 3. The electron gun according to claim 1, wherein a part of the upper cathode crosses an imaginary straight line connecting the anode and the filament. The electron gun according to any one of claims 1 to 3, characterized in further comprise a columnar projection provided upright on the space of the cathode in a state where the tip portion is disposed in the vicinity of the cathode of the opening .   The electron gun according to claim 1, wherein the filament is linear.   6. An electron beam generator comprising: the electron gun according to claim 1; and a magnetic field generator for deflecting and focusing an electron beam emitted from the electron gun.

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