JPH0381259B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a hollow cathode used in neon sign discharge tubes, gas laser tubes, and the like.

[Prior art and its problems]

The cathode used in conventional neon sign discharge tubes, gas laser tubes, etc. has a main body 1 formed into a horn shape or a cylindrical shape, with the opening P facing the opposite electrode, as shown in FIGS. 1a and b. It is common for the inner surface to be operated by an action called hollow cathode discharge.

However, these cathodes emit discharge light on the side of the opening P, but the discharge light cannot be seen on the side. Therefore, when using this cathode in a discharge tube for a neon sign, a display light source is configured as shown in Figure 2. Since the ratio of the electrode parts B, B, which do not contribute to discharge light emission, to the tubular part A is large, it is necessary to take measures such as placing the electrode parts B, B, which do not emit light, on the back side of the display light source during use. .

One possible solution to this problem is to use a flat plate electrode, but since a flat plate electrode cannot supply a sufficient discharge current, a large cathode area is required.
Cannot be used for neon signs. Therefore, it has been desired to develop a hollow discharge cathode that can supply a discharge current without such drawbacks as a cathode for cold cathode discharge tubes.

Note that the neon sign discharge tube is operated in an alternating current discharge state, and the anode is operated by the action of the tip portion on the opposing electrode side when the conical or cylindrical electrode is in a positive voltage state.

[Means for solving problems]

The present invention has been made in order to solve the above-mentioned problems, and the main body is formed in a U-shaped or V-shaped cross section, and hollow cathode discharge is performed on the opposite electrode side and the side facing the tube wall of the discharge lamp. It has an opening.

[Effect]

In the cathode according to the present invention, light emission from a discharge portion called a negative glow formed on the inner surface during operation can be seen through an opening provided toward the tube wall. Therefore, for example, when the cathode of the present invention is introduced into a discharge tube for a neon sign, light emission due to negative glow is seen at the cathode section, and light emission from a positive column is seen at the tube section leading to the anode, and the whole tube is illuminated. It is possible to realize a display light source with a large occupancy rate of the light emitting portion.

[Embodiment] FIG. 3 shows an embodiment of the present invention, which is a conventional horn-shaped cathode divided into two.
That is, the main body 1 has a U-shaped cross section, and openings P and Q for hollow cathode discharge are provided on the opposite electrode side and the side facing the discharge lamp tube wall.

Figures 4 to 7 show other different embodiments; Figure 4 shows a cylindrical shape divided into two;
Figure 5 shows the shape of a rhombic pyramid divided into two parts,
The figure shows the shape of a rectangular cylinder divided into two, and FIG. 7 shows the shape of a deformed rhombic cylinder divided into two.

Figures 8 to 10 show still other different embodiments, with Figure 8 having a double conical shape divided into two, and Figure 9 having a double prismatic cylinder divided into two. The shape shown in FIG. 10 is the shape shown in FIG. 6 in which a partition plate 2 is arranged, and the light emitting surface area is increased in both cases.

These cathodes have openings P and Q on the opposite electrode side and on the tube wall side, respectively, and a hollow cathode discharge occurs at each opening to emit light.

FIG. 11 shows a partially cutaway side view of the Neowa discharge tube equipped with the cathode shown in FIG. 10, and almost the entire length C can be used as a display light source.

〔Effect of the invention〕

According to the present invention, it is possible to increase the effective light emitting area of a discharge lamp that performs hollow cathode discharge, and there is an effect that it is not necessary to take conventional measures such as bending the electrode portion of the discharge lamp. This will greatly contribute to the field of technology that uses .

[Brief explanation of drawings]

FIG. 1 is a perspective view of a conventionally used cathode, FIG. 2 is a partially cutaway perspective view of a conventional neon sign discharge tube, and FIGS. 3 to 10 are perspective views of embodiments of the present invention. 11 is a partially cutaway perspective view of the discharge tube for a neon sign using the cathode according to the present invention shown in FIG. 10. 1...Main body, P, Q...Opening.

Claims (1)

[Claims] 1. A cathode for a discharge lamp, characterized in that the main body has a U-shaped or V-shaped cross section, and an opening that functions as a hollow cathode is provided on the opposing electrode side and on the side facing the tube wall of the discharge lamp.