JPH0535557Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to an electron gun device used in an electron beam irradiation device or the like.

(Prior art) The third electron beam irradiation device equipped with an electron gun device
The structure shown in the figure is already known.
In the figure, 1 is a container whose inside is evacuated, 2 is a cylindrical electrode, 3 is an electron gun device, 4 is a filament thereof, 5 is a grid, and 6 is a window for taking out an electron beam.

When the filament 4 is heated to a high temperature of, for example, about 2200 to 2300°K, electrons are emitted. The emitted electrons are extracted to the outside of the electrode 2 by the grid 5. Then, due to the voltage applied between the electrode 2 and the container 1, the light is radiated to the outside through the window 6.

By the way, as a conventional electron gun device used in such an electron beam irradiation device, one having a configuration as shown in FIG. 4 is known. This is done by inserting each end of the filament 4 through a pair of insulating stands 7 and 8, and attaching it to a fitting 9 that can slide freely along the length of the filament on the insulating stand, and to this using screws or the like. The tip of the filament 4 extracted from the insulating base is sandwiched between the filament 4 and the fixing fitting 10 and fixed thereto.

The metal fittings 9 are positioned, for example, in a staggered manner on the insulating stands 7 and 8, so that each filament 4 is connected in series. In this configuration, as described above, the filament 4 is heated to a high temperature by being energized, so that it expands and becomes longer. If the electricity is turned off, it will contract again. In response to such expansion and contraction, the metal fitting 9 slides to absorb the expansion and contraction.

However, the force due to the expansion and contraction of the filament 4 concentrates on the metal fittings that fix it, and in some cases, the fixing metal fittings may not slide smoothly. If this happens, the beam extraction portion at the center of the filament 4 will become curved or otherwise deformed.

In order to improve this problem, a configuration has been considered in which a compressed spring 11 is interposed between each insulating stand 7, 8 and a fixture 10, as shown in FIG. According to this, the filament 4 is constantly pulled by the elasticity of the spring 11 via the fixing fitting 10, so that the filament 4 is always in a stretched state.

However, according to this, when the filament 4 contracts, the tension necessary to pull the fixing fitting 10 against the elasticity of the spring 11 is applied to the filament 4.
join. Therefore, it is necessary to select the spring 11 according to the mechanical strength of the filament, and if the selection is incorrect, the filament may break. Moreover, since the spring 11 itself becomes plasticized by heating, it no longer functions as a spring. Therefore, selection of this spring 11 is extremely difficult.

(Problem that the invention attempts to solve) This invention proposes that the filament that makes up the electron gun
The purpose is to easily prevent thermal deformation due to expansion and contraction.

(Means for solving the problem) In this invention, the filament is made into a U-shape, and both ends of the filament are fixed to an insulating stand with fixing fittings, and the curved part of the tip is supported slidably on another insulating stand. It is characterized by what it did.

(Example) An example of this invention will be described with reference to FIGS. 1 and 2. Note that parts given the same reference numerals as in FIG. 4 indicate the same or corresponding parts. According to this idea, a filament 4 is formed into a U-shape, each end of which is formed into an insulating base 7, and inserted into a hole 12.
The tip protruding from is fixed with a metal fitting 9 and a fixing metal fitting 10. The metal fitting 9 is not slidable on the insulating stand 7. On the other hand, the curved part side of the filament 4 is
It is slidably inserted into a hole 13 formed in the insulating base 8, thereby mechanically supporting this curved portion side.

The illustrated example shows a case where a plurality of filaments 4 are used as shown in FIG. 2. Here, each filament 4 is arranged in parallel, and adjacent filaments 4
The leg portions 4A arranged side by side are fixed to the same metal fitting 9, thereby connecting the filaments in series.

In the above configuration, it is assumed that the filament 4 is expanded by being heated as described above. Since the end of the filament 4 is fixed to the metal fitting 9 of the insulating stand 7 by the fixing metal fitting 10,
The leg portions 4A begin to expand toward the insulating stand 8 side. At this time, the leg portion 4A slides within the hole 13, but if the frictional resistance with the hole 13 at that time is set to be sufficiently small, no particularly large restraining force will act on this expansion. This reliably prevents thermal deformation during expansion.

In the illustrated example, the filament is inserted into a hole formed in the insulating base, but instead of the hole, the filament may be inserted into a groove extending from the upper edge of the insulating base.

(Effects of the invention) As detailed above, according to this invention, thermal deformation due to expansion and contraction of the filament can be reliably prevented, and the structure for this purpose can be extremely simple.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing an embodiment of this invention;
3 is a sectional view showing an example of an electron beam irradiation device, FIG. 4 is a plan view of a conventional example, and FIG. 5 is a sectional view of the conventional example. 4...Filament, 7, 8...Insulation stand, 9...
...Metal fittings, 10...Fixing metal fittings.

Claims (1)

[Scope of utility model registration request] U is a filament that emits electrons when heated.
What is claimed is: 1. An electron gun device in which the filament has a letter-shaped shape, both ends of which are fixed to an insulating stand with fixing metal fittings, and a curved portion at the tip of the filament is slidably supported on another insulating stand.