JPH0247080B2 - TENTOKAN - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lighting tube, and more particularly to an improvement in the structure of a lighting tube that reliably supplies a high kick voltage to a discharge lamp such as a high-pressure discharge lamp to facilitate lighting.

Lighting tubes generally have a bimetallic electrode of a thermally responsive element supported by welding or the like to an internal lead-in wire planted in the stem in an airtight container filled with an easily dischargeable electrical substance such as argon. When the electrodes come into contact with each other due to discharge, and when the discharge is cut off and the bimetal is separated because it is no longer heated by the discharge, a high kick voltage of about 2000V or even higher voltage is generated due to the inductance of the ballast.
For example, it starts the discharge of a high-pressure discharge lamp such as a metal halide lamp or a high-pressure sodium lamp. As shown in the partially cutaway front view of FIG. 1, a conventional lighting tube is supported by welding on internal lead-in wires 3, 3 planted in a stem 2 sealed to the end of an airtight container 1. There is a distance 7, 7 between the end portions 5, 5 of the bimetal 4, 4 that are close to the stem surface and the stem surface 6, and the internal lead-in wires 3, 3 are connected therebetween.
was exposed. 8, 8 are contacts fixed to the tips of bimetals 4, 4, 9, 9 are internal lead-in wires 3, 3
The outer conductor 10 is electrically conductively connected to the sealed end of the exhaust pipe. The internal lead-in wire exposed between the end of the bimetal and the stem surface is made of nickel, iron, nickel alloy, etc., and has a cylindrical shape. Since it is heated and there is oxide on the surface, if a high voltage of 2000V or more is generated, the voltage will be transferred to the internal lead-in wire 3,
Arc discharge between 3 and creeping discharge along the stem surface 6 are likely to occur.Furthermore, due to repeated operation of the lighting tube, the surface of the internal lead-in wire is scattered due to the sharp voltage, causing sharp angles on the surface. Since small protrusions are easily formed, arc discharge is likely to occur from the protrusions even at a kick voltage of 2000 V or less. When such arc discharge or creeping discharge occurs, the kick voltage for lighting the high-pressure discharge lamp is affected by the above discharge. As a result, the kick voltage absorbed within the lighting tube and supplied to, for example, a high-pressure discharge lamp is reduced, resulting in a drawback that the high-pressure discharge lamp no longer lights.

The present invention has been made in view of the above-mentioned drawbacks, and provides an improved structure that does not absorb the harsh voltage in the lighting tube and can therefore reliably supply the required high voltage to, for example, a high-pressure discharge lamp. The object of the present invention is to provide a lighting tube having the following characteristics.

The details of the present invention will be explained below with reference to an embodiment of the present invention shown in the second figure. FIG. 2 is a partially cutaway front view of an embodiment of the present invention, showing a stem 2 with internal lead-in wires 22, 22 planted at the end of an airtight container 21.
3 is sealed. The internal lead-in wires 22, 22 are electrically conductively connected to the outer conductive wires 24, 24, and the outer conductive wires 24, 24 are hermetically sealed to the stem 23. Electrodes 25, 25 made of bimetallic thermally responsive elements are fixed to the internal lead-in wires 22, 22 by welding their ends. Contact points 26, 26 made of round metal rods are adhesively fixed by welding to the tips of electrodes 25, 25 made of bimetallic thermally responsive elements so as to form a diagonal cross. The air in the airtight container 21 is exhausted via the exhaust pipe 27 connected to the stem 23, and the tip of the exhaust pipe 27 is sealed by filling the airtight container 21 with a readily dischargeable electric substance such as argon at a predetermined pressure. A sealed end 28 is formed. Note that metal barium or the like may be coated on the inner wall of the airtight container 21 as an electron radiation source if necessary, but this is omitted in FIG. 2. Electrode 25 consisting of a thermally responsive element
The discharge space of is 29. An electrode 25 made of a thermally responsive element is provided on the discharge space 29 side of the internal lead-in wire 22.
The thermally responsive element 30 has its end 32 on the stem surface 31.
The heat-responsive element 30 is tightly welded and fixed to the internal lead-in wire 22, so that the thermally responsive element 30 covers the discharge space 29 side of the internal lead-in wire 22.

Next, the functions and effects of the lighting tube of the present invention will be described. As is clear from FIG. 2, in the lighting tube of the present invention, the bimetallic thermally responsive element has its end in close contact with the stem surface on the discharge space side. The internal lead-in wire made of nickel, iron, nickel alloy, etc. is covered so that it is not exposed at all to the discharge space of the electrode made of the thermally responsive element. Therefore, the surface of the cylindrical internal lead-in wire and the oxidation of the internal lead-in wire during stem manufacturing or when welding an electrode made of a bimetallic thermally responsive element to the internal lead-in wire may cause arc discharge of oxides. Since the portion that is likely to become an electrode that generates arc discharge or creeping discharge is completely covered by the planar thermally responsive element, it is possible to prevent the occurrence of arc discharge or creeping discharge. Furthermore, according to experiments conducted by the present inventors, it was confirmed that the same effect was obtained when the easily discharged electric material sealed in an airtight container was used with helium, neon, or a mixture of two or more gases selected from these, in addition to argon. did. Among the above elements, helium and neon are effective for generating high kick voltage when used in lighting tubes of high-pressure discharge lamps. The effects are excellent and large. In addition, in the embodiment, an electrode made of a thermally responsive element was provided on both sides of the internal lead-in wire, but according to experiments by the present inventors, a configuration in which a thermally-responsive element covers the internal lead-in wire is only possible on one side. Even if the internal lead-in wire is only on the internal lead-in wire side, or even if one of the internal lead-in wires is configured such that the discharge space side is covered by a thermally responsive element and the other internal lead-in wire does not have a thermally responsive element, There is no difference in the effect, and this can be prevented by covering only one side of the internal lead-in wire with a thermally responsive element, that is, by making only one electrode in a shape that makes it difficult to discharge. It seems to be.

As detailed above, the present invention comprises an airtight container, a stem sealed to the end of the airtight container and having an internal lead-in wire planted therein, and a thermally responsive element supported by at least one of the internal lead-in wires. and an easily discharging electric body filled in the airtight container, wherein at least one of the thermally responsive elements has an end portion in close contact with the stem surface on the discharge space side of the internal lead-in wire, and It is a lighting tube characterized by covering the lead-in wire, and in the lighting tube of various discharge lamps, especially high-pressure discharge lamps such as metal halide lamps and high-pressure sodium lamps, between the internal lead-in wires in the lighting tube. Since no arc discharge or creeping discharge occurs on the stem surface, the high voltage that occurs will not be absorbed and lowered, and therefore the discharge lamp can be lit extremely reliably. This has the effect that it is possible to provide a lighting tube having characteristics that are similar to those described above.

[Brief explanation of drawings]

Figure 1 is a partially cutaway front view of a conventional lighting tube;
The figure is a partially cutaway front view of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 21... Airtight container, 22... Internal lead-in wire, 23... Stem, 25... Electrode consisting of a thermally responsive element, 29... Discharge space, 30... Thermally responsive element, 31... Stem surface, 3
2...End portion of the thermally responsive element.

Claims (1)

[Scope of Claims] 1. An airtight container, a stem sealed to an end of the airtight container and having an internal lead-in wire planted therein, and an electrode comprising a thermally responsive element supported by at least one of the internal lead-in wires. and an easily discharging electric body filled in the airtight container, wherein at least one of the thermally responsive elements has an end thereof in close contact with the stem surface on the discharge space side of the internal lead-in wire, and the internal lead-in wire is A lighting tube characterized by being covered. 2. The lighting tube according to claim 1, wherein the easily discharged electric body is made of one or more gases selected from neon, helium, and argon.