JPH0227652A - Low-pressure discharge lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to low pressure discharge lamps such as fluorescent lamps and germicidal lamps.
In particular, it relates to small, high-efficiency, low-pressure discharge lamps.

[Conventional technology]

As a low-pressure discharge lamp that utilizes discharge between the ends of substantially one hot cathode, the one described in Japanese Utility Model Publication No. 43-6315 is known.

[Problem to be solved by the invention]

In the conventional low-pressure discharge lamp described above, one end of one hot cathode functions as a cathode and the other end functions as an anode. In the case of AC lighting, one end serves as a cathode and an anode alternately. During the anode cycle, the problem arises that the hot cathode is overheated, the electron-emitting material evaporates, and the tube wall becomes black.

An object of the present invention is to provide a compact low-pressure discharge lamp with less blackening of the tube wall.

[Means to solve the problem]

In order to achieve the above object, the low pressure discharge lamp of the present invention is provided with an anode close to the hot cathode.

[Effect]

When the anode is placed close to the hot cathode, discharge occurs between the end of the hot cathode and the anode. Therefore, the thermionic emitting material is not overheated during the anode cycle, and blackening of the tube end is prevented.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure shows a germicidal lamp with a tungsten double coil inside a discharge vessel 4 made of ultraviolet-transparent glass.

A hot cathode 1 coated with a thermionic emission material 5 mainly composed of SrO and CaO is provided, and an anode 2.3 is provided on lead wires 22.23 supporting both ends of the hot cathode 1. . The discharge gases were argon and mercury at 5 Torr.

When an AC voltage is applied to the lead wires 22 and 23 through a discharge stabilizing capacitor or choke coil, the end 1 of the hot cathode 1 is
2 becomes a cathode and a discharge occurs between it and the anode 3. In a cycle in which the lead wire 22 is negative and the lead wire 23 is positive, the end 13 of the hot cathode 1
serves as a cathode, and discharge occurs between it and the anode 2. That is, the hot cathode 1 is not overheated during the anode cycle, thus eliminating blackening of the tube wall. Since the anode 23 simply functions to collect electrons, metals that do not evaporate easily, such as tungsten, tantalum, and nickel, can be used as the material, so that it does not evaporate even when heated, and blackening does not occur.

In conventional low-pressure discharge lamps that discharge between the ends of one hot cathode, it is necessary to fold the hot cathode to bring the distance between the ends closer, and a lead wire is required to support the folded part. , a stem with three leads was required.

In the present invention, since a separate anode is provided, a long linear hot cathode can be used, and therefore only two lead wires are required, resulting in the advantage that the stem structure is simplified.

〔Effect of the invention〕

According to the present invention, a small-sized low-pressure discharge lamp with less blackening of the tube wall can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention.

Claims (1)

[Claims] 1. A low-pressure discharge lamp having substantially one hot cathode, characterized in that an anode is provided in close proximity to the hot cathode.