JP2005353436A - Low-pressure mercury vapor discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-pressure mercury vapor discharge lamp with temperature rise at an end of a bulb restrained at end of life. <P>SOLUTION: A glass stem 2 each having a glass flare part 2b is sealed in at either end of a glass bulb 1 with a phosphor film inside, and a cap each with two pin terminals erected is firmly fixed to both end part of the glass bulb 1. The glass stem 2 is provided with a thick part 2a and a thin part 2b with one end communicated with the thick part 2b and the other end welded to the end of the glass bulb 1. The thick part 2a is a main body sealing part of the glass stem retaining lead wires 3a, 3b. The thin part 2b is the glass flare part, to which metal films 6a, 6b are attached. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a low pressure mercury vapor discharge lamp.

When a low-pressure mercury vapor discharge lamp, such as a fluorescent lamp, reaches the end of its life by depleting the emitter (electron emitting material) applied to the electrode, the temperature around the electrode rises due to various factors. Proposal to incorporate a thermal fuse in the lamp for the purpose of prevention (for example, Patent Document 1), proposal to stop discharge between electrodes by arc extinguishing gas discharge (for example, Patent Document 2), and a ceramic plate or glass bead in the vicinity of the electrode There are known proposals (for example, Patent Documents 3 and 4). In addition, a proposal is made to stop discharge by thinning a part of the thickness of the glass stem at the end of the lamp, thereby breaking the thin part formed in the glass flare part by heat due to excessive rise in filament temperature and leaking the discharge vessel (for example, patent) Document 5) is known.
Japanese Patent No. 3032504 Japanese Patent No. 2980548 JP 11-238458 A JP-A-6-338289 JP 2003-331787 A

  The progress of the end-of-life phenomenon of the fluorescent lamp due to the exhaustion of the emitter is strongly influenced by the electronic lighting circuit that is combined and lit, but as a whole the cathode fall voltage rises, the filament current increases, etc. As long as the electronic lighting circuit does not stop lighting, the lamp end will be considerably hot. All of the techniques described in Patent Documents 1 to 5 described above are countermeasure techniques provided in the lamp, and it can be said that the emphasis is placed on lowering the over-temperature rise transition probability at the lamp end. In addition, when examining each countermeasure technology, it was not a countermeasure technology that could handle all types of fluorescent lamps. Even if the thermal fuse application technique (Patent Document 1) is used, it cannot be adopted for all fluorescent lamps due to dimensional restrictions, temperature application range restrictions, and the like.

  In particular, in the proposal for breaking the discharge vessel by heat and stopping the discharge by leaking (Patent Document 5), a thinner glass flare portion of the glass stem is provided with a thinner thin portion. In addition, it is difficult to produce a thinner and thinner part in the glass flare part, and it is difficult to take measures to improve the quality reliability and product yield related to product strength because it has a thinner part than the normal thickness. There is a problem of being.

  The present invention is unnecessary at the end of the lamp when it is used in combination with a step-up winding type electronic lighting circuit having a high circuit voltage that can maintain lighting even after the emitter is depleted and the filament electrode is disconnected. An object of the present invention is to obtain a low-pressure mercury vapor discharge lamp capable of inducing a temperature rise due to a discharge at a specific location at the end of the discharge lamp when the discharge occurs, and stopping the discharge at an early stage.

  The low-pressure mercury vapor discharge lamp of the present invention is a fluorescent lamp in which a glass stem holding an electrode is sealed at both ends of a glass bulb, and the glass stem is sealed with two lead wires on which the electrode is laid. A thin part with a small thickness relative to the thick part, the thick part being held, and one end connected to the thick part and the other end welded to the end of the glass bulb It has the structure by which the metal body was provided in the said thin part.

  According to the present invention, the excessively raised heat is locally collected in a metal body provided in the thin part of the glass stem, and the thin part of the glass stem is melted by the heat concentrated on the metal body to open a hole. It is possible to stop the lamp end from being overheated. For this reason, even when the emitter is depleted from the electrode of the fluorescent lamp and it is lit with a lighting circuit of a type having a lighting maintaining ability even after the electrode is disconnected, an unnecessary discharge occurs at the end of the lamp at the end of its life. In this case, overheating of the lamp end can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The fluorescent lamp according to the first embodiment of the present invention (hereinafter referred to as product A of the present invention) is a type of FHF32 (fluorescent lamp enclosing mercury vapor not exceeding 1 Pa and argon buffer gas of approximately 300 Pa), Glass stems 2 having glass flare portions (thin portions 2b) are respectively sealed at both ends of a glass bulb 1 having a phosphor film (not shown) inside, as shown in FIG. The bases 9 (see FIG. 6) on which the terminals 9 a are erected are fixed to both ends of the glass bulb 1.

  The glass stem 2 has a thick portion 2a, and one end thereof is connected to the thick portion 2a, and the other end is welded to the end of the glass bulb 1, with respect to the thickness of the thick portion 2a. And a thin thin portion 2b. In the thick portion 2a, two lead wires 3a and 3b provided with a tungsten filament electrode 5a coated with a small amount of the emitter 4 are erected and sealed, and the lead wires 3a and 3b are held. It is a main body sealing part of the glass stem 2 which is. The thick portion of the glass stem 2 usually refers to a portion where the lead wires 3a and 3b are crushed and sealed, that is, the thick portion 2a, and is formed thicker than the thickness of the glass flare portion described later.

  The thin part 2b is a so-called glass flare part formed integrally with the thick part 2a. On the surface of the glass avoiding the thick part of the glass stem 2, that is, the glass flare part which is the thin part 2b, a partial metal body in two places, in this embodiment, a metal film (substantially circular and its diameter) Is about 3 mm, the thickness is 1 μm, and the material is silver powder coating) 6a, 6b.

  In this embodiment, the height of the glass stem 2 (symbol A), that is, the distance between the welded portion of the glass bulb 1 and the glass flare portion and the electrode side end surface of the thick portion 2a is 25 mm, the end surface of the base 9 and the thick portion. The distance (symbol B) from the electrode-side end surface of 2a was 30 mm, the thickness of the thick portion 2a that was crush-sealed and flattened was 3 mm, and the thickness (symbol C) of the thick portion 2a was 5 mm. Moreover, the thickness of the glass flare part was 0.7-1.0 mm. The metal films 6a and 6b may be provided at one place, but are preferably provided at two places. Moreover, it is preferable to provide in at least one place of the glass stem 2 of both ends. The two metal films 6a and 6b are preferably installed at positions separated from each other on the side surfaces of the glass stem 2. This is because when an unnecessary discharge occurs at the end of the life, the discharge easily jumps to the metal bodies that are the metal films 6a and 6b.

  As shown in FIG. 2, the fluorescent lamp according to the second embodiment of the present invention (hereinafter referred to as the present product B) has the metal films 6a and 6b and the bases of the lead wires 3a and 3b in the present product A as shown in FIG. The conductive wires 7 a and 7 b are electrically connected by silver powder, and the conductive wires 7 a and 7 b are provided along the surface of the glass stem 2. The conducting wires 7a and 7b may be in contact with the surface of the glass stem 2 or may not be in contact with each other. However, in the present invention, at least a part of the metal bodies that are the metal films 6 a and 6 b needs to be in contact with the glass stem 2.

  As shown in FIG. 3, the fluorescent lamp according to the third embodiment of the present invention (hereinafter referred to as “the product C of the present invention”) is a surface of the glass stem that avoids a thick portion of the glass stem 2, ie, the present invention. Similarly to the product A, metal cones (cones) 8a and 8b made of nickel are attached as metal bodies having protrusions at two locations of the glass flare portion.

  As shown in FIG. 4, a fluorescent lamp according to a fourth embodiment of the present invention (hereinafter referred to as the product D of the present invention) is based on the product C of the present invention and has metal cones (cones) 8a and 8b made of nickel and leads. The wires 3a and 3b are electrically connected to the conductive wires 7a and 7b in the same manner as the product B of the present invention.

  On the other hand, as a comparative product, a conventional fluorescent lamp (hereinafter referred to as a comparative product) using a glass stem 2 having nothing provided on the surface of the glass stem was prepared.

  These products A to D of the present invention and comparative products are turned on by a winding step-up transformer / preheat lighting type inverter (see FIG. 5), and after the emitter electrode 4 is depleted from the one-side filament electrode 5a, the filament electrode is disconnected. Overheating history that each lamp end receives under such conditions (the time from when the emitter 4 is depleted until the glass stem 2 is broken and the discharge stops, and the maximum temperature reached at the bottom of each lamp base; 10 samples each (Average and fluctuation range). The results are shown in Table 1. Note that the inverter used for the evaluation of the present invention has a small internal impedance of the filament current circuit, and because of its low constant current property, the glass stem 2 is simply melted by breaking the shape between the two lead wires 3a and 3b. There is no ability. However, this inverter has sufficient ability to partially soften the glass stem by local discharge heating on the surface of the glass stem 2 on which the tungsten metal of the filament electrode 5a is sputter deposited after the emitter 4 is depleted. .

  As is apparent from Table 1, in the fluorescent lamps of the present invention products A to D, the time from when the emitter is depleted until the lamp is stopped can be shortened compared to the comparative product, and the maximum temperature reached at the end face of the base 9 Could be greatly reduced.

  Next, the results of Table 1 will be considered.

  The result of the products A and C of the present invention was better than that of the comparative product (the time until the lamp was turned off was short and the rise in the base temperature was low) because the glass avoiding the thick part of the glass stem 2 The partial metal films 6a and 6b and the metal cones 8a and 8b deposited at two locations on the surface of the metal plate are electrically coupled to a tungsten sputtered film to be described later, and the glass stem 2 portion provided with the metal body is formed. This is because it contributed to the breakage caused by overheating. In the invention product A and the invention product C, the time to stop the ramp is faster in the invention product C because the protrusions are present in the metal films 6a and 6b of the product C. This is thought to be because the electric field strength was increased and it was easy to receive discharge heating.

  On the other hand, the result of the product B of the present invention is better than the result of the product A of the present invention, or the result of the product D of the present invention is better than the result of the product C of the present invention. This is probably because the conductive wires 7a and 7b made of silver powder are electrically coupled to the lead wires 3a and 3b and the metal films 6a and 6b from the beginning of the emitter depletion) and thus are easily subjected to discharge heating. . That is, particularly in the products A and C of the present invention, tungsten, which is the material of the filament electrode, is scattered by sputtering after the cathode 4 is depleted and then the cathode fall voltage rises, and the surface of the glass stem 2 is sputtered with tungsten. The lead wires 3a, 3b and the metal films 6a, 6b are electrically connected to facilitate discharge heating. In the products C and D of the present invention, the lead wires 3a and 3b and the metal films 6a and 6b are electrically connected in advance, so that the lead wires 3a and 3b and the metal films 6a and 6b are accidentally connected. It is considered that the lamp is stopped earlier than the products A and B of the present invention using the tungsten sputtered film formed in a typical manner.

  The reason why the result of the product D of the present invention was the best is that both the effect of the product B of the present invention and the effect of the product C of the present invention were combined. Incidentally, the cross section of FIG. 1 is shown in FIG. 6. If the glass stem 2 is to be broken by local melting on the glass surface avoiding the thick portion of the glass stem 2, the metal films 6 a and 6 b are installed. There is no need to inquire about the location and the glass thickness, and conventional glass component materials (glass thickness is 0.7 to 1.0 mm) can be used as they are.

  From the above results, the present invention can promote the breaking of the glass stem 2 after the end of the lamp life (emitter depletion), and can prevent abnormal overheating of the lamp end.

  In the second or fourth embodiment of the present invention, the conductive wires 7a and 7b made of silver powder drawn from the base of the lead wires 3a and 3b along the surface of the glass stem 2 are connected to the lead wires 3a and 3b and the metal. Although used for electrical coupling of the films 6a and 6b, other metal materials may be used. Further, as the metal body, a member obtained by extending a connector that is electrically coupled to the lead wires 3a and 3b from the metal body is used. The connector is locked to the lead wires 3a and 3b, and the metal body is made of glass. A glass surface that avoids a thick portion of the stem 2 such as a glass flare portion may be provided. In this embodiment, the fluorescent lamp of FHF32 has been described as an example. However, the present invention can be widely applied to other types of fluorescent lamps and low-pressure discharge tubes.

  The present invention adds a means to promptly stop the lighting on the lamp side against a problem that starts from exhaustion of the emitter and eventually leads to an excessive rise of the lamp end temperature. The present invention can be effectively applied to a fluorescent lamp whose reliability can be increased more than ever.

1 is a partially cutaway perspective view of an end of a fluorescent lamp according to a first embodiment of the present invention. The partially cutaway perspective view of the fluorescent lamp end portion according to the second embodiment of the present invention The partially cutaway perspective view of the fluorescent lamp end portion according to the third embodiment of the present invention Partially cutaway perspective view of an end of a fluorescent lamp according to a fourth embodiment of the present invention Circuit diagram for lighting test of low-pressure mercury vapor discharge lamp of the present invention The partially cutaway front view of the fluorescent lamp end part which is the first embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass bulb 2 Glass stem 3a, 3b Lead wire 4 Emitter 5a Electrode 6a, 6b Metal film 7a, 7b Conduction wire 8a, 8b Metal cone 9 Base

Claims (3)

In a fluorescent lamp in which a glass stem holding an electrode is sealed at both ends of a glass bulb, the glass stem has a thick portion where two lead wires on which the electrode is installed are sealed and held, One end portion is connected to the thick portion, and the other end portion is welded to the end portion of the glass bulb, and has a thin portion that is thin relative to the thick portion, and the thin portion A low-pressure mercury vapor discharge lamp characterized by comprising a metal body. 2. The low-pressure mercury vapor discharge lamp according to claim 1, wherein the metal body is electrically coupled to at least one of the lead wires. The low-pressure mercury vapor discharge lamp according to claim 1 or 2, wherein the metal body has a protrusion.

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