JP2000011857A - Fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent lamp that can prevent the thermal damage to its base from occurring due to an abnormal overheat of an electrode part caused by abnormal discharge at a life terminal stage. SOLUTION: In this fluorescent lamp, a flare stem 2 at an end of an arc tube 1 is pierced with a pair of internal lead wires 3, a filament 4 is formed at the inner ends of the internal lead wires 3 inside the arc tube 1, and external introduction wires 5 are locked by a base pin 6 and fixed to a base 7. In this case, the base 7 is formed from ceramics for the purpose of thermal damage prevention.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp for preventing thermal damage to a base caused by abnormal overheating near the electrode, which occurs very rarely at the end of life of high frequency lighting.

[0002]

2. Description of the Related Art Generally, a ring-shaped fluorescent lamp and a compact fluorescent lamp use a resin base. However, when such a fluorescent lamp is turned on at a high frequency, the lamp maintains discharge even when the electron emitting material applied to the filament at the end of its life is exhausted, and discharges the filament or the internal lead wire which has lost the electron emitting material as an electrode. Sometimes. In this case, particularly when the internal lead wire discharges, the lead wire is melted by the discharge current and the heat melts the stem, and in the worst case, the resin base is partially melted, which may result in thermal damage.

[0003] Another end-of-life phenomenon in high-frequency lighting is a filament material (W), an electron-emitting material (BaO or the like) applied to the filament, and an internal lead wire (Ni, Fe, etc.) holding the filament. ) Splatters,
It adheres and accumulates on the glass near the base of the lead wire near the filament. In particular, scattering becomes severe at the end of the lamp life, and these adhere to the glass near the base of the lead wire.
Easy to deposit.

[0004] Since the above-mentioned deposits are conductive substances, they may conduct electricity when deposited. Therefore, a conductive path may be formed between a pair of internal leads insulated by the scattered substance adhered and deposited on the glass portion near the base of the lead, and thereby conduction between the internal leads may occur.

[0005] In such a case, after the filament is broken, a current flows through a conductive path formed by the attachment and deposition of the scattered substance between the pair of internal leads, generating heat, and thermally destroying the glass near the root of the lead. In the worst case, as described above, the resin base provided at the end of the arc tube may be partially damaged and may be damaged by heat.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is an object of the present invention to prevent a heat damage to a resin base which occurs very rarely at the end of life in high frequency lighting. It is an object of the present invention to provide a fluorescent lamp that can be used.

[0007]

In order to achieve the above-mentioned object, in order to achieve the above object, a sealing member made of glass and a pair of metal lead wires is hermetically sealed, and the pair of internal lead wires inside the arc tube is used. In a fluorescent lamp provided with a filament at the inner end, this is achieved by providing a base made of ceramics at the end of the arc tube.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described based on an embodiment shown in FIG. FIG. 1 is a partial sectional view of an end of a compact fluorescent lamp. In the figure, reference numeral 1 denotes an arc tube made of a glass tube having a phosphor coating on the inner surface. The end of the arc tube 1 is closed by a flare stem 2.
The flare stem 2 is made of nickel-coated iron wire φ
A pair of 0.6 mm internal lead wires 3 are air-tightly penetrated, and a filament 4 made of tungsten is provided at the end of each of these internal lead wires 3. Filament 4
Is coated with an electron emitting material such as barium oxide. Further, the internal lead wire 3 is connected to the external lead-in wire 5, locked by a base pin 6, and fixed to a base 7 made of ceramics.

The effect of the lamp thus configured was confirmed using a compact fluorescent lamp.

The lamp of the present invention and the conventional lamp were operated in combination with a ballast for high-frequency operation, and an experiment was conducted on thermal damage of a base at the end of life. In this case, one of the electrodes of the test lamp was coated with an electron-emitting substance in a coating amount as designed, and the other electrode was coated with a very small amount of the electron-emitting substance to promote consumption. Further, only the portion near the electrode was not coated with the fluorescent film, and the inside was observed.

As a result of the experiment, the filament 4 and the electron emitting material applied to the filament 4 or the scattered material generated by evaporation of the internal lead wire 3 adhere to and accumulate on the tip of the flare stem 2, thereby causing the internal lead wire. Electric current flowed between the front surfaces of the flare stems 2 between 6, and the surface of the front surface of the flare stem 2 near the lead wire and the flare stem 2 were thermally damaged. As a result of this experiment, in the conventional lamp, four lamps with a part of the base melted were generated in 100 experiments. However, in the lamp with the base 7 made of ceramic of the present invention, thermal damage such as melting was observed in 150 experiments. Not at all. Due to this result, it rarely occurs at the end of life at the time of high frequency lighting,
It has been found that the present invention can prevent thermal damage of the die due to abnormal overheating of the electrode portion.

In this embodiment, a base 7 made of ceramics is used.
The material used is steatite, which is an insulating ceramic, but any other insulating ceramic such as forsterite, alumina, or zircon may be used.

FIG. 2 and FIG. 3 (a) show a base 7 made of ceramics provided with radiating fins 8 for radiating heat according to the present invention. FIG. 3 (b) shows a cross section of the lamp base of FIG. 3 (a). In the case where thermal damage to the base occurs due to abnormal overheating of the electrode part occurring at the end of the lamp life at the time of high frequency lighting, the temperature of the base reaches approximately 250 ° C. At this time, the base made of ceramics will not be damaged,
Due to the high temperature, accidents such as thermal damage or burns to the equipment are expected and very dangerous. Therefore, the present invention provides the heat dissipation fins 8 on the ceramic base 7 so as to minimize the temperature rise of the base due to abnormal discharge at the end of life in such high-frequency lighting, and to further reduce the base part after the discharge ends. Temperature can be accelerated.

As a result of the experiment, it was confirmed that the maximum temperature was lowered by 10 to 20 ° C., and the rate of temperature decrease in the die after the discharge was terminated was increased.

[0015]

As described above, according to the present invention, the conventional resin base is replaced with a ceramic base to prevent heat damage to the base caused by abnormal overheating of the electrode part at the end of life at the time of high-frequency lighting. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing an end portion of a fluorescent lamp according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing an end of a fluorescent lamp according to one embodiment of the present invention.

FIG. 3 is a partial sectional view showing an end of a fluorescent lamp according to one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Arc tube, 2 ... Flare stem, 3 ... Internal lead wire, 4
... filament, 5 ... introduction wire, 6 ... base pin, 7 ... ceramic base, 8 ... radiation fin.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Soichiro Ogawa 6-chome, Shinmachi, Ome-shi, Tokyo 2 F-term in the Heater Lighting Division, Hitachi, Ltd. (Reference) 5C035 HH01 HH11 HH14

Claims (3)

[Claims] 1. A sealing member made of glass and a pair of metal leads is hermetically sealed to a sealing end of an arc tube, and a filament is attached to ends of the pair of internal metal leads inside the arc tube. A fluorescent lamp provided with a base made of ceramics. 2. The fluorescent lamp according to claim 1, wherein said base made of ceramics is made of insulating ceramics such as steatite, alumina, forsterite, and zircon. 3. The fluorescent lamp according to claim 1, wherein the base made of ceramic is a base provided with fins for heat radiation.