JPH11238487A - Low-pressure mercury vapor discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend the like and enhance the efficiency by providing an electrode comprising two metal plates having mercury alloy mounted on one-surface sides which are opposed to each other so that the mercury alloy surfaces are situated outside. SOLUTION: This discharge lamp has an electrode having a mercury alloy Ti3Hg 15 and the like held on each of one-surface sides of metal plates 11, 12 consisting of iron-nickel alloy. The mercury alloy Ti3Hg15 and the like are provided on the outside of the metal-plates 11, 12 opposite to each other, and an alloy getter 13 and the like containing Zr and Al are provided on the opposed surfaces of the metal plates 11, 12. When a low-pressure discharge lamp having such an electrode is lighted by discharge current, a cathode glow gets into a clearance formed by the two metal plates 11, 12 by a so-called hollow cathode effect. Consequently, since the sputtering of the metal Ti forming an alloy with mercury which is provided on the outside of the metal plates 11, 12 is not caused, the metal Ti never reaches a tube wall. Thus, it never forms an alloy with mercury on the tube wall, and the life can be extended.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a low-pressure mercury vapor discharge lamp, and more particularly to a small-diameter low-pressure mercury vapor discharge lamp such as a fluorescent lamp for a backlight.

[0002]

2. Description of the Related Art A hot cathode discharge lamp and a cold cathode discharge lamp are described in the Illumination Handbook (edited by
Moon, Ohmsha) on pages 759 to 760. The hot cathode fluorescent lamp is described on page 160 of the same document. The structure of the hot cathode is described on page 121 of the Lighting Handbook (November 1987, Ohmsha) edited by the Illuminating Engineering Institute of Japan.

[0003]

The above-mentioned conventional diameter of 20 mm
As described above, in a hot cathode low-pressure discharge lamp using at least mercury vapor as a discharge gas, granular mercury is sealed from an exhaust pipe having an inner diameter of about 4 mm. However, the inner diameter of the discharge lamp is 8mm
When the temperature was below, the diameter of the exhaust pipe naturally became smaller, and it became difficult to fill in the particulate mercury. Therefore, a mercury alloy was attached to a part of the electrode, a rare gas or the like was sealed in the discharge lamp and hermetically sealed, and then the mercury was sealed by high-frequency heating of the mercury alloy to release mercury. .

In the above-mentioned conventional low-pressure discharge lamp, discharge occurs on the mercury alloy during operation, and the metal forming an alloy with mercury scatters and adheres to the tube wall to form an alloy again with mercury. Is no longer evaporated, and the life is shortened. In particular, when the discharge current was 6 mA or more, the amount of the metal that forms an alloy with mercury scattered, and the above-mentioned problems were greatly affected.

An object of the present invention is to provide a low-pressure mercury vapor discharge lamp having a long life and high efficiency.

[0006]

An object of the present invention is to provide a so-called hollow, wherein two metal plates having a mercury alloy mounted on at least one surface thereof are opposed to each other so that the mercury alloy is on the outside. This is achieved by providing a shaped cold cathode. Further, by installing the two metal plates in a substantially parallel flat plate shape and setting the distance d between the flat plates between 0.1 mm and 1.0 mm, higher efficiency and longer life can be obtained. Further, when the main component of the discharge gas is a rare gas and the atomic weight of the rare gas is M, the pressure of the rare gas expressed in Torr is set to 280 / M or more and 2000 / M or less, so that the above object is further achieved. Achieved.

When a pair of so-called hollow-type cold cathodes is provided, in which two metal plates each having a mercury alloy mounted on at least one surface thereof are opposed to each other so that the mercury alloy is on the outside, a so-called hollow cold cathode is provided. Due to the hollow cathode effect, the cathode glow enters the gap created by the two metal plates, and the discharge is mainly performed inside the hollow. Will not be scattered by. Therefore, the metal that forms an alloy with mercury does not form an alloy again with mercury on the tube wall, and as a result, a long life is obtained. Furthermore, by installing the two metal plates in a substantially parallel plate shape and setting the distance d between the metal plates to between 0.1 mm and 1.0 mm, the cathode glow surely enters the hollow, and As a result, the cathode drop voltage decreases due to the so-called hollow cathode effect, and the cathode loss decreases, so that a highly efficient low-pressure discharge lamp can be obtained. Further, the above-mentioned effect is obtained by setting the main component of the discharge gas to a rare gas and setting the rare gas pressure expressed in Torr to 280 / M or more and 2000 / M or less when the atomic weight of the rare gas is M. Achieved even more.

[0008]

FIG. 1 shows a first embodiment of the present invention. Cathodes 1 and 2 are sealed at both ends of a straight tubular discharge vessel 4, and each of the cathodes 1 and 2 has one lead wire 5,
6 is connected. Since there is only one lead wire, the structure of the tube end of the discharge tube is simplified, and there is an advantage that the manufacture is simple. The advantage of the simple structure of the tube end is greater when the inner diameter of the discharge tube is 8 mm or less.

FIG. 2 is a perspective view of the electrode used in the embodiment of FIG. Metal plate 1 made of 3mm wide iron-nickel alloy
Mercury alloy Ti ₃ Hg 15, 16 on one side
(Not shown) is held. Mercury alloy Ti ₃
Hg 15 and 16 (not shown) are provided outside the metal plates provided opposite to each other. Metal plate 11, 1
The two opposing surfaces are provided with alloy getters 13 and 14 (not shown) containing Zr and Al.

A fluorescent substance 3 is applied to at least a part of the inner surface of the discharge tube 1. When the phosphor coating film 3 is present, when the electrodes 1 and 2 are inserted, the electrodes 1 and 2 come into contact with the phosphor film 3 to cause the phosphor to fall off or the blackening of the tube end to be more noticeable. One electrode is provided with one lead wire,
This is particularly advantageous.

In FIG. 1, the discharge tube 4 has an inner diameter of 5.7 mm,
A soda glass tube having a length of 270 mm and a rare earth phosphor Y ₂ O ₃ : Eu, MgAl ₁₁ O ₁₉ : Ce, T
b, and applying a mixture of _{3Sr 3 (PO 4) 2 ·} CaCl 2. The discharge gas is 10 Torr of argon and mercury vapor. Mercury heats the metal plates 11 and 12 to about 900 ° C by high-frequency heating.
Generated by

The low-pressure discharge lamp of the present invention is 30 kHz,
When the lamp was turned on with a discharge current of 10 mA, a cathode glow was generated by the so-called hollow cathode effect.
12 into the gap created by the metal plate 1
Sputtering of metal Ti which forms an alloy with mercury provided outside of 1, 12 did not occur. Therefore, the metal Ti did not reach the tube wall, and did not form an alloy again with mercury on the tube wall, so that a long life was obtained.

FIG. 3 is a perspective view of the electrode of the second embodiment. In the electrode of this embodiment, two metal plates 11 and 12 are installed in a substantially parallel plate shape, and the distance d between the metal plates is 0.3 m.
m, mercury alloy Ti ₃ Hg18 (not shown).
15 is provided on the outside. A getter 1 made of an alloy of Zr and Al is provided on opposing surfaces of the metal plates 11 and 12.
3, 14 (not shown) are provided. When the above electrode was used, the cathode drop voltage was reduced by 20% as compared with the case where d exceeded 1 mm, and a high efficiency fluorescent lamp was obtained. Also,
The metal which forms an alloy with mercury was not scattered by sputtering, so that mercury was less likely to be alloyed, and a high efficiency and long life fluorescent lamp was obtained.

According to the embodiment of the present invention, a low-pressure discharge lamp having a long life and high efficiency can be obtained. Further, a low-pressure discharge lamp having a simple tube end structure can be obtained, and there is an advantage that the manufacturing method is simplified.

[0015]

According to the present invention, it is possible to obtain a low-pressure mercury vapor discharge lamp having a longer life than before.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIGS. 2 and 3 are perspective views of an electrode of the embodiment of the present invention.

[Explanation of symbols]

1, 2, ... electrode, 11, 12, ... metal plate, 13 ... getter,
15 ... Mercury alloy.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Soichiro Ogawa 888 Fujibashi, Ome-shi, Tokyo Inside the Ome Plant of Hitachi, Ltd.

Claims (6)

[Claims] 1. A low-pressure mercury vapor discharge lamp comprising two metal plates each having a mercury alloy mounted on one surface thereof and opposed to each other such that a surface of the mercury alloy faces outward. . 2. The low pressure apparatus according to claim 1, wherein the two metal plates are installed in a substantially parallel flat plate shape, and a distance d between the flat plates is between 0.1 mm and 1.0 mm. Mercury vapor discharge lamp. 3. When the main component of the discharge gas is a rare gas and the atomic weight of the rare gas is M, the pressure of the rare gas expressed in Torr is 2
3. The low-pressure mercury vapor discharge lamp according to claim 2, wherein the lamp pressure is 80 / M or more and 2000 / M or less. 4. The low-pressure mercury vapor discharge lamp according to claim 2, wherein said electrode is connected to one lead wire. 5. The low-pressure mercury vapor discharge lamp according to claim 2, wherein the inner diameter of the discharge tube of the discharge lamp is 8 mm or less. 6. An alloy getter is provided on opposing surfaces of said two metal plates.
A low-pressure mercury vapor discharge lamp as described.