JPH01102844A - Low pressure mercury vapor discharge lamp - Google Patents

Abstract

PURPOSE:To prevent electric discharge at the time of pyrolysis of an emitter substance attached to an electrode by supporting an aux. amalgam by a column cable insulated electrically from an internal lead, and setting the shortest distance of this aux. amalgam from the internal lead and electrode to a value over 2mm. CONSTITUTION:An aux. amalgam 13 is insulated electrically from an internal leads 9, and the shortest distance from the electrode 10 and internal lead 9 is set to a value over 2mm. Therefore, no electric discharge will occur between the aux. amalgam 13 and internal lead 9 even though a voltage drop arises between the ends of the electrode 10 when the emitter substance attached to the electrode 10 is pyrolyzed by electric heating. This causes flow of regular dissolution current in the electrode 10 to allow sure dissolution of the emitter substance on the electrode 10, which should relieve ill affection on the lamp characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a low-pressure mercury vapor discharge lamp in which the mercury vapor pressure within a glass tube is controlled by an amalgam.

BACKGROUND OF THE INVENTION It has been known in the past for low-pressure mercury vapor discharge lamps to use an amalgam to control the mercury vapor pressure within the tube within an appropriate range in order to prevent a decrease in luminous efficiency at high temperatures. However, this product uses the characteristic that the mercury vapor pressure of amalgam is lower than that of pure mercury to control the mercury vapor pressure. The disadvantage is that the optical output has a slow rise and takes time to reach a steady state. To solve this problem, in addition to the main amalgam that controls the mercury vapor pressure during lighting, we welded an auxiliary amalgam that temporarily releases mercury at the beginning of lighting to the internal lead wires near the electrodes at both ends of the glass tube. A device with improved optical output rise characteristics is known.

Problems to be Solved by the Invention However, in the initial stage of lighting, this auxiliary amalgam is placed near the electrodes so that mercury is quickly supplied into the glass tube based on heating by radiant heat from the electrodes. The free end of the side not welded to the wire becomes close to the internal lead wire of the non-welded side.

For this reason, when the emitter material deposited on the electrode is thermally decomposed by electrical heating in the evacuation process, an electric discharge occurs between the free end of the metal member of the auxiliary amalgam and the opposing internal lead wire. A portion of the current that should flow through the electrode ends up flowing into the bypass circuit due to discharge. Therefore, the decomposition of the emitter material is insufficient and the lamp characteristics are impaired. In addition, when starting and lighting the lamp, auxiliary amalgam is welded to the internal lead wire, and since the auxiliary amalgam is composed of a metal member coated with amalgam-forming metal, it is welded. It has the same potential as the side electrode, and the auxiliary amalgam also acts as part of the electrode. As a result, sputtering of the amalgam-forming metal deposited on the metal member occurs, causing blackening of the wall of the arc tube, which adversely affects the life of the lamp.

The present invention provides a low-pressure mercury vapor discharge lamp which can prevent undesired local discharge during decomposition of the emitter material and sputtering of the auxiliary amalgam-forming metal during startup and operation with a simple construction.

Means for Solving the Problems The low-pressure mercury vapor discharge lamp of the present invention has a lamp located at one end of the glass tube, closer to the tube end than an electrode, to control the mercury vapor pressure inside the tube during steady lighting. A main amalgam is provided, and an auxiliary amalgam is provided near the electrode at one end of the glass tube, and the auxiliary amalgam is supported by support wires that are electrically insulated from a pair of internal lead wires that conduct electricity to the electrodes. , and has a configuration in which the shortest distance between the auxiliary amalgam and the internal lead wires and electrodes is set to 2 mm+ or more.

According to the present invention, since the auxiliary amalgam is supported by the strut wire electrically insulated from the internal lead wire and is appropriately spaced from the electrode and the internal lead wire, the auxiliary amalgam and the auxiliary amalgam during decomposition of the emitter material are Discharge between the lamp and the internal lead wire and sputtering of the amalgam-forming metal during lamp startup and lighting can be reliably prevented.

Embodiment In FIG. 4, reference numeral 1 denotes an envelope, which is composed of, for example, a case 3 made of resin and equipped with an E-shaped cap 2, and a globe 4 made of transparent resin or glass. This envelope 1 is divided by a partition plate 5 into two spaces: a space 1a for three cases and a space 1b for four gloves.

A lighting device such as a ballast and a glow starter is provided in the space 1a, and a double U-shaped arc tube 6, for example, is provided in the space 1b. As shown in FIG. 1, the arc tube 6 includes, for example, a double U-shaped glass tube 7, a stem 8 sealed at both ends of the glass tube 7, and two internal lead wires 9 implanted in the stem 8. and electrodes 10 fixed to the tips of these
and the main amalgam 1 arranged in the exhaust pipe 11 of the stem 8.
2, the glass rod 14, the auxiliary amalgam 13, which is a porous rectangular metal member coated with an amalgam-forming metal, and has an adhered part 13a and a non-adhered part 13b, and the internal lead wire 9. The support wire 15 is electrically insulated and supports an auxiliary amalgam 13. The auxiliary amalgam 13 is mounted on the support wire 15 by welding the non-adhered portion 13b of the metal member. As shown in FIG. 2, when the auxiliary amalgam 13 is welded to the strut wire 15, the shortest distance L2 between the metal member and the internal lead wire 9 facing it and the shortest distance L1 between the electrode 10 are 2 m.
It is set above.

FIG. 3 shows a horizontal sectional view of a low-pressure mercury vapor discharge lamp according to an embodiment of the present invention.

In this way, the auxiliary amalgam 13 is electrically insulated from the internal lead wire 9, and the electrode 10 and the internal lead wire 9
Since the shortest distance from the auxiliary amalgam 13 is set to 2 or more, even if a voltage drop occurs between both ends of the electrode 10 when the emitter material deposited on the electrode 10 is thermally decomposed by heating with electricity, the auxiliary amalgam 13 and No discharge occurs between the inner lead wire 9 and the inner lead wire 9. For this reason, as a result of a regular decomposition current flowing through the electrode 10, the emitter material of the electrode 10 can be reliably decomposed, and the adverse effect on the lamp characteristics can be alleviated.

Moreover, even during startup and lighting, the above-mentioned Ll and L2 are set to 2- or more, and the auxiliary amalgam 13 is supported by the support wire 15 which is electrically insulated from the internal lead wire 9. , are electrically insulated from the electrode 10, and are not affected by electrons and various ions generated inside the glass tube 7 during startup and lighting, and can prevent sputtering of the amalgam-forming metal of the auxiliary amalgam 13. The effect on lamp characteristics can also be alleviated by

If the above-mentioned shortest distance, L2, is less than 2-, and a part of the auxiliary amalgam 13 comes into contact with either one of the internal lead wires 9, the contact between the auxiliary amalgam 13 and the internal lead wire 9 occurs during thermal decomposition of the emitter material. Electric discharge is likely to occur between the internal lead wire and the lead wire on the other side (and the emitter substance cannot be sufficiently decomposed. Moreover, if one of the internal lead wires 9 and the auxiliary amalgam 13 come into contact with each other, the auxiliary amalgam 13 will act as a part of the electrode 10, causing sputtering of the amalgam-forming substance of the auxiliary amalgam.Furthermore, even if the lead wire 9 and the auxiliary amalgam 13 do not contact, if Ll and L2 are less than 2-, the above-mentioned problem will occur. A similar phenomenon occurs.Therefore, the shortest distances L1 and L2 are each set to 21w or more, and the auxiliary amalgam 13 is supported by a support wire 15 that is electrically insulated from the internal lead wire 9. is necessary.

In addition, in the present invention, for example, the shape of the glass bulb is double U.
In addition to the shape, you can change it to U-shape, ring shape, etc. as appropriate. In addition, auxiliary amalgam can be placed at both ends of the glass tube,
In addition to applying an amalgam-forming metal to a metal member by plating or the like and then contacting it with mercury, it is also possible to apply amalgam from the beginning.

As described in detail, according to the present invention, the auxiliary amalgam is supported by support wires that are electrically insulated from the internal lead wires, and the shortest distance between the auxiliary amalgam and the internal lead wires and electrodes is Since it is set at 2 wm or more, it is possible to prevent discharge during thermal decomposition of the emitter material deposited on the electrode, and also to prevent sputtering of the auxiliary amalgam forming material during startup and lighting, which has an adverse effect on lamp characteristics. It is possible to provide a low-pressure mercury vapor discharge lamp that can alleviate the

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view showing the main parts of a low-pressure mercury vapor discharge lamp which is an embodiment of the present invention, Fig. 2 is the same (partially cutaway side view), and Fig. 3 is the same (horizontal sectional view, Fig. 4 is a partially cutaway front view showing an application example of the low-pressure mercury vapor discharge lamp of the present invention. 7...Glass tube, 9...Internal lead wire, 10... ...Electrode, 12...Main amalgam, 13...Auxiliary amalgam. Name of agent: Patent attorney Toshio Nakao 1 idiot Figure 2

Claims (1)

[Claims] A main amalgam is provided at one end of the glass tube to control the mercury vapor pressure inside the tube during steady lighting by being located closer to the tube end than the electrode, and near the electrode at at least one end of the glass tube. In a low-pressure mercury vapor discharge lamp provided with an auxiliary amalgam, the auxiliary amalgam is supported by a column wire that is electrically insulated from a pair of internal lead wires that conduct electricity to the electrodes, and the auxiliary amalgam is A low-pressure mercury vapor discharge lamp characterized in that the shortest distance between the lamp and the lamp is set to 2 mm or more.