JPH0565969B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an electron beam irradiation device.

(Prior Art) In an electron beam irradiation device, when an object to be irradiated is irradiated with an electron beam to be emitted, there are cases where it is desired to arbitrarily change the width of the electron beam. Conventionally, this has been done by adjusting the electric field within the electron gun, but if the electron beam is band-shaped, adjustment using the electric field is extremely difficult.

(Problems to be Solved by the Invention) An object of the present invention is to easily control the width of the electron beam even when the electron beam is band-shaped.

(Means for Solving the Problems) This invention utilizes the magnetic field used when performing vertical magnetic field alignment treatment on an object to be irradiated. The side surface of the magnetic pole for magnetic field orientation is arranged so as to face the passage of the electron beam toward the irradiated object, and a yoke of arbitrary relative magnetic permeability is installed on the side surface of the magnetic pole. .

(Function) Since the tips of the magnetic pole and yoke face the surface of the object to be irradiated, the magnetic flux from the magnetic pole and yoke passes perpendicularly to the object to be irradiated, so that the object to be irradiated is vertically aligned by the magnetic field. be done. At this time, part of the magnetic flux leaks from the side surface of the yoke installed on the side surface of the magnetic pole and enters the path of the electron beam.

Therefore, this leakage magnetic flux crosses the above-mentioned leakage magnetic flux along the width direction of the electron beam. The electron beam is focused or diverged by this intersection. The degree of convergence or divergence at this time is changed depending on the amount of the leakage magnetic flux.

On the other hand, this leakage magnetic flux changes depending on the relative magnetic permeability of the yoke. Therefore, by using a yoke with a relative magnetic permeability selected according to the width of the electron beam to be adjusted, it becomes possible to irradiate the object with an electron beam having the desired width. .

Note that instead of using yokes with different relative magnetic permeabilities, it is also possible to adjust the magnetic flux from the magnetic poles by changing the current flowing through the coil. However, in order to orient the irradiated object with a vertical magnetic field, the amount of magnetic flux is determined depending on the irradiated object. It is practically impossible to adjust the current flowing.

(Example) This invention will be explained with reference to the drawings. Reference numeral 1 denotes an electron beam generation source, which is mainly composed of a vacuum container 2, and has an irradiation window 2A provided in a part of its peripheral wall, from which an electron beam is emitted toward the outside. An electron gun 3 is installed inside. This is mainly composed of an electrode 4 made of, for example, a pipe, a filament 5 inside which generates an electron beam, and a grid 6.

A magnet device 7 is composed of a pair of electromagnets 8 and 9 placed across a path P of an irradiated object A such as a magnetic medium such as a magnetic tape. Each electromagnet is composed of a core 11 having a magnetic pole 10 and a coil 12 wound around the core 11. A window 13 is formed in the center of this core 11. The irradiation window 2A is inserted into the window 13 of the upper electromagnet 8.

Further, a yoke 14 is installed on the side surface of the magnetic pole 10 so as to face the window 13 of the upper electromagnet 8. This yoke 14 is selectively provided with a relative magnetic permeability necessary to make the electron beam a desired width. In this way, the magnetic pole 10, the yoke 1
The tip of the yoke 14 faces the surface of the object A passing through the passage P, and the side surface of the yoke 14 faces the side surface of the electron beam traveling toward the object A. Note that the arrow shown by a solid line in the figure indicates the direction in which the object A to be irradiated is transported.

In the above configuration, the electron beam from the electron beam source 1 is irradiated onto the irradiated object A through the irradiation window 2A, and the magnetic pole 1 of the magnet device 7 is applied to the irradiated object A.
0, the magnetic flux from the yoke 14 passes vertically. As a result, the magnetic paint applied to the surface of the irradiated object A is cured by electron beam irradiation with the magnetic particles oriented in a vertical magnetic field. Such an operation is not particularly different from the manufacturing process of ordinary magnetic tapes.

At this time, a part of the magnetic flux directed toward the yoke 14 becomes leakage magnetic flux L passing through the window 13. The amount of this leakage magnetic flux L changes depending on the relative magnetic permeability of the yoke 14. That is, the smaller the relative magnetic permeability, the greater the amount of leakage magnetic flux L.

On the other hand, an electron beam (indicated by B in FIG. 3) directed toward the irradiated object A exists in this window 13. Therefore, the leakage magnetic flux L intersects with the electron beam, and the width of the electron beam is focused or diverged by this intersection. Therefore, by selecting a material with an arbitrary relative magnetic permeability as the yoke 14 and changing the leakage magnetic flux L, the width of the electron beam can be adjusted arbitrarily.

In the above explanation, it is assumed that the yoke 14 is installed on the side surface of the magnetic pole 10, but this yoke 14
Place the vacuum container 2 so that it is located on the side of the irradiation window 2A.
It may also be attached to. Furthermore, it is convenient if the yoke 14 is made removable, since it can be replaced depending on the adjustment width.

(Effects of the Invention) As described in detail above, according to the present invention, a part of the magnetic flux for vertical magnetic field alignment processing is made into a leakage magnetic flux that intersects with the electron beam directed toward the irradiated object, and furthermore, this leakage magnetic flux is Since it is changed by the relative magnetic permeability of the yoke located on the side of the magnetic pole, the width of the electron beam can be easily and freely adjusted by appropriately setting the material of this yoke and adjusting the leakage magnetic flux as desired. When it becomes possible, it produces great effects.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, in which the front is a perspective view in section, FIG. 2 is a partially enlarged sectional view, and FIG. 3 is a partially plan view. 1... Electron beam source, 2A... Irradiation window, 7...
Magnet device, 8, 9... Electromagnet, 10... Magnetic pole, 1
4... Yoke, P... Passage, A... Irradiated object.

Claims (1)

[Claims] 1. The tip of the magnetic pole of a magnet device that generates magnetic flux for subjecting the irradiated object to vertical magnetic field alignment processing is made to face the surface of the irradiated object that is transported along the path, and the side surface of the magnetic pole is placed so as to face the surface of the irradiated object that is transported along the path. An electron beam irradiation device in which a yoke with a desired relative magnetic permeability is installed facing the passage of the electron beam toward the irradiation object and on the side surface of the magnetic pole so that leakage magnetic flux from the yoke intersects with the electron beam. .