JPH04341749A - Gaseous discharge tube - Google Patents

Abstract

PURPOSE:To improve the brightness of a gaseous discharge tube as a spot light source by setting a depth of an aperture conical hole part in an electron convergence part to be almost the same depth as that of a high density electron zone so as to generate the high density electron zone along an optical axis. CONSTITUTION:An electron convergence part 5 comprises an aperture 6 of metal such as molybdenum where a conical hole part 12 and a small diameter hole part 11 communicate with each other. For the hole part 12, an angle thetais set to be 30-120 deg., or preferably 60 deg. and a depth L1 is set to be 2mm or more, or preferably 4mm, which is the same degree as that of a high density electron zone 16. For the hole part 11, a depth L2 is set at about 1mm, and a diameter (d) is set at 0.4-2.0mm, or preferably at 0.6mm. An electron way 9 from a cathode to an anode gets closer to an optical axis 2 at a convergence part 5 for an electron current to get in almost linearly, and light outgoing from the zone 16 toward a side is also reflected at the inner surface of the hole part 12 to be refracted in the direction of the optical axis 2 to reduce loss, thereby the brightness can be improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas discharge tube such as a deuterium lamp used for analysis, quantitative measurement, etc.

0002

2. Description of the Related Art As shown in FIGS. 5 and 6, a conventional gas discharge tube, for example, a deuterium lamp, has an anode 3 disposed on an optical axis 2 within a sealed container 1 made of transparent glass. 3
The outer periphery of the electrode is surrounded by a shielding electrode 4. Further, an electron converging section 5 is provided in front of the anode 3, and an aperture 6 narrowed into a conical cylinder shape is provided on the anode side of the electron converging section 5. A light transmission hole 7 is provided in front of this electron convergence section 5.
is open, and a cathode 8 is provided on the side. This cathode 8 is surrounded by shielding electrodes 4 on three sides, but a barrier plate 10 is provided so as to open only the part of the electron path 9 through which electrons to the anode 3 pass.

[0003] In such a deuterium lamp, several Torr of deuterium gas is sealed in a transparent glass sealed container 1, and after preheating the cathode 8, a trigger voltage is applied between the anode 3 and the cathode 8 to generate an arc. Discharging is started, and after discharging, the main power supply voltage is applied to continue discharging. Here, the electron converging section 5 is made of metal such as molybdenum, and the aperture 6 is composed of a small diameter hole section 11 and a conical hole section 12. As shown in FIG. 4, in the conventional aperture 6, the angle θ of the conical hole 12 is generally 60°, and the depth L1 of the conical hole 12 is 1.3 m.
m, and the hole diameter d of the small diameter hole portion 11 is 0.4 to 2.0 mm.
The depth L2 of the small diameter hole portion 11 was 0.5 mm.

0004

It has been found that the depth L1 and angle θ of the conical hole 12 of the aperture 6, particularly the depth L1, have a significant effect on whether or not the brightness increases. That is, in the gas discharge tube, electrons are concentrated into the electron convergence section 5 by discharge, so that the electron density becomes high, and as a result, a high-density electron region 16 is generated at the position of the aperture 6. However, since the electron path 9 from the cathode 8 to the anode 3 takes the shortest possible distance, it passes near the upper surface 15 of the aperture 6 of the electron focusing section 5.

As a result, in the conventional gas discharge tube, the high-density electron region 16 generated by electron convergence is
As shown by the intersecting diagonal lines, in the upper part of the electron convergence section 5, the electrons are biased considerably toward the cathode 8 side than the optical axis 2, and the high-density electron region 16 appears to expand. This has been an obstacle to increasing the brightness of the gas discharge tube, which should be a point light source. Furthermore, more light is emitted from the high-density electron region 16 in a direction far away from the optical axis 2, and this loss increases.

An object of the present invention is to obtain a gas discharge tube with improved brightness by appropriately setting the aperture shape of the electron focusing section.

[0007]

[Means for Solving the Problems] The present invention provides a gas discharge tube comprising an electron convergence section on the front surface of an anode in a closed container filled with gas, in which an aperture is provided in the electron convergence section. The aperture is a gas discharge tube characterized in that its depth is at least substantially the same as or greater than the high-density electron region.

[0008]

[Operation] The electron flow emitted from the cathode is narrowed down by the electron convergence section and reaches the anode. At this time, the depth of the aperture of the electron convergence section was set to be at least approximately the same as the height of the high-density electron region. Then, a high-density electron region generated in the electron convergence section is generated along the optical axis and is prevented from spreading toward the cathode, so that the brightness of the point light source increases.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. The first embodiment of the present invention will be described with reference to FIG. 1. Since the shape other than the electron focusing section 5 is the same as that of FIGS. 5 and 6 showing the conventional example, the same parts are given the same reference numerals.

Electron focusing section 5 in the first embodiment of the present invention
The aperture 6 is formed using a metal such as molybdenum. This aperture 6 is formed so that the conical hole portion 12 and the small diameter hole portion 11 communicate with each other.
2, the angle θ is 30 to 120°, preferably 6
0°, and its depth L1 is approximately the same depth as the high-density electron region 16, specifically, 2 mm or more, preferably 4 mm. The small diameter hole 11 has a depth L2 of about 1 mm and a diameter d.
is 0.4 to 2.0 mm, preferably 0.6 mm.

By configuring the conical hole portion 12 deeply as described above, the electron path 9 from the cathode 8 to the anode 3 is formed as shown in FIG.
As shown by the dotted line, the electron flow approaches the optical axis 2 at the electron convergence section 5 and enters the electron flow approximately linearly. Therefore, the high-density electron region 16 does not spread toward the cathode 8 side.
Even if there is light generated within the conical hole 12 of the electron convergence section 5 facing the optical axis 2 and emitted laterally from the high-density electron region 16, the light is reflected by the inner surface of the conical hole 12. The light is refracted in the direction of axis 2, and the loss becomes extremely small, resulting in improved brightness.

Next, FIGS. 2 and 3 show other embodiments of the present invention, and in this example, the conical hole portion 12
In order to increase the depth L1, a cylindrical body 14 is integrally connected to the upper surface 15 of a conventional electron focusing section 5 as shown in FIG. The cylindrical body 14 may have a conical shape continuous to the conical hole 12, as shown in FIG. 2, or may have a cylindrical shape with a larger diameter than the conical hole 12, as shown in FIG. good.

In FIGS. 2 and 3, a taper 17 is provided so that the incident point of the electron path 9 from the cathode 8 is low and the opposite side is high, so that the electron flow is smoothly guided to the anode 3. I'm trying to get away from it.

As described above, with the configurations shown in FIGS. 2 and 3, the high-density electron region 16 is aligned with the optical axis 2 as in FIG.
The brightness is improved.

In the embodiments shown in FIGS. 1 and 2, the cathode 8
Although an example has been shown in which the cathode 8 is disposed on the side of the electron converging section 5, the cathode 8 may be disposed below (or above) the electron converging section 5 (not shown).

The shape of the conical hole 12 of the electron converging section 5 is appropriately determined depending on the purpose of use. For example, when condensing the light to one point on the optical axis 2, it is shaped like an ellipse, when it is made into parallel light, it is shaped like a parabola, and when obtaining diffused light, the surface of the conical hole 12 is shaped with a non-uniform diffusion surface. Make it. With the above configuration, more effective use can be achieved.

[0017]

[Effects of the Invention] As described above, in the present invention, the depth of the conical hole of the aperture in the electron convergence section is approximately the same depth as the high-density electron region, so that the electron flow from the cathode to the anode is directed to the electron convergence section. incident substantially linearly along the optical axis, and a high-density electron region is generated along the optical axis. Therefore, the brightness of the gas discharge tube as a point light source is improved.

Incidentally, FIG. 7 shows a characteristic curve comparing the optical outputs of the conventional electron converging section and the electron converging section of the present invention. In this case, the conventional product has L1=1.3mm, θ=60°,
d=0.6mm, the first invention product has L1=4.0mm,
θ=60°, d=0.6mm, discharge current 0.3A
, the tube voltage was set to 75±5V, and the electrical electron convergence shape was measured under the same conditions. As a result, the characteristic line (B) shows the case of the conventional gas discharge tube shown in FIG.
The characteristic line (A1) shows the characteristic line according to the first product of the present invention. In addition, the characteristic line (A2) is θ
= 30° (Other L1 = 4.0mm, d = 0.6mm
, discharge current 0.3A, and tube voltage 75±5V are the same). From these characteristic diagrams, characteristic line (A1) (A
In case 2), an increase in the amount of light of 70% or more was obtained, and the luminance was about 2.5 times higher than that of the conventional characteristic line (B). In addition, L
Experiments were conducted by varying the value of 1 and the value of θ, and it was found that the effect of increasing brightness has almost no relation to the value of θ, but is related to the value of L1.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of an electron focusing section of a gas discharge tube according to the present invention.

FIG. 2 is a cross-sectional view showing a second embodiment of the invention.

FIG. 3 is a sectional view showing a third embodiment of the present invention.

FIG. 4 is a cross-sectional view of a conventional electron focusing section.

FIG. 5 is a cross-sectional view of a conventional gas discharge tube.

FIG. 6 is a longitudinal cross-sectional view of FIG. 5;

FIG. 7 is a characteristic curve diagram.

[Explanation of symbols]

1... Airtight container, 2... Optical axis, 3... Anode, 4... Shielding electrode, 5
...Electron convergence part, 6...Aperture, 7...Light transmission hole, 8...Cathode, 9...Electron path, 10...Barrier plate, 11...Small diameter hole part, 12
... Conical hole portion, 14 ... Cylindrical body, 16 ... High-density electron region.

Claims (2)

[Claims] Claim 1: On the front surface of an anode in a closed container filled with gas,
In a gas discharge tube equipped with an electron convergence section, an aperture is formed in the electron convergence section, and the aperture has a depth that is at least approximately the same as or greater than the high-density electron region. gas discharge tube. 2. The gas discharge tube according to claim 1, wherein the aperture communicates with the conical hole and the small diameter hole, the conical hole has a depth of 2 mm or more, and a conical angle of 30° to 120°.