JPH06203800A - Small sized fluorescent lamp - Google Patents

Abstract

PURPOSE:To provide a small sized fluorescent lamp wherein also the decay of brightness can be suppressed while suppressing a crack and a slow leak in an air-tight seal part. CONSTITUTION:Tungsten 21 is used as lead wires 2 for constituting an air-tight seal part, and a glass winding part 3 of borosilicate glass is provided in a nonoxidation condition in a predetermined section of a pair of these lead wires 2. An arc tube of 10mm or less internal diameter consisting of borosilicate glass is provided to seal between itself and this glass winding part 3.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a compact fluorescent lamp,
In particular, the present invention relates to a small fluorescent lamp used as a backlight of a laptop type or book type personal computer or a liquid crystal display device of a word processor.

[0002]

2. Description of the Related Art Laptop and book type personal computers,
Small fluorescent lamps for backlights used in display devices that use liquid crystal panels, such as word processors,
Unlike ordinary fluorescent lamps for general lighting, it is required to have small dimensions and low power consumption, high luminous efficiency, high brightness, and long service life. In particular, since these devices are for consumer use, it is a rule not to replace the lamp, and it is required to have a lighting life of 10,000 hours or more. Also, the brightness is required to be a value close to 20000 nt for a color display.

Therefore, in a small fluorescent lamp for a backlight, the current and voltage, the amount of rare gas for starting and the amount of mercury enclosed are determined so as to be compatible with low power consumption, and it is also optimal from the viewpoint of lighting life. Electrode design is made. Then, it is turned on by a high frequency power source to obtain required luminance and color rendering properties.

By the way, in such a small fluorescent lamp, as in the conventional general fluorescent lamp,
An arc tube mainly made of lead glass is used, and the lead wire of the seal portion is a Dumet wire in which an oxide film of copper is formed on the surface of an iron-nickel alloy. Then, the surface of the Dumet wire is oxidized while being heated with a burner in an oxidizing atmosphere to wind the glass, and the arc tube made of lead glass is sealed to the glass winding portion, which is a so-called oxide film sealing method. . (For example, see "Recent Advances in Lighting Glass", Journal of the Lighting Society, Vol. 69, No. 1 (1985), pages 6-7).

[0005]

There have been many studies and reports on the sealing structure of the lead wire of the lamp, but there have been many studies (for example, “Adhesion mechanism of glass and metal (1)”, Material No. 17, Volume 180). Issue (September 1968) P783 to 792, "Chemical bonding between glass and metal in hermetic sealing", Vol. 73, Industrial Chemistry.
No. 1 (1970) P35-40, `` Adhesion mechanism between ceramics and glass and metal '', Volume 18, No. 10 (1980) P562-572, etc.)
The oxide film sealing method is difficult to control the process, and if not properly controlled, it will cause cracks and slow leaks in the sealing portion and shorten the lamp life.

In the oxide film sealing method, the reason why cracks and slow leaks are likely to occur in the sealing portion will be explained.
First, if there are too many oxide films on the copper surface or if the welding temperature is too low, the copper oxide film layer becomes thick and the compatibility with glass becomes poor, and leakage from this part is likely to occur. In particular, since the glass winding part formed on the surface of the Dumet wire is heated strongly when the arc tube is sealed, the glass winding part will move slightly along the dumet wire if it is a little uncomfortable with the glass. , Slow leak becomes easy.

Even if the oxide film on the copper surface is moderate, if the welding temperature is too high or the welding time is too long, copper oxide or copper will enter the inside of the glass and the copper film will become thin. In this case, the compatibility between copper and glass is good, but when the copper film becomes thin, it becomes vulnerable to thermal shock, and when it is heated in the subsequent process
The nickel alloy and copper may peel off and cause a slow leak. Furthermore, when the Jimet wire is heated strongly in a later step, copper may boil to cause bubbles in the glass winding portion, or the iron-nickel alloy that is the core metal and copper may deviate to cause slow leak. .

Lead glass (soft glass) has a strain point temperature of 39.
Since the temperature is about 5 ° C., which is lower than that of hard glass (about 500 ° C.), strain remains unless slowly cooled while sufficiently controlling the temperature to a low temperature. For this reason, cracks may occur in heating processes such as exhausting and soldering in a later process. If the residual strain is extremely large, cracks may occur even if it is left to stand naturally.

Next, in such a small fluorescent lamp, the factors of attenuation of the brightness during the travel include deterioration of the phosphor, blackening of the tube wall due to sputtering of the electrode material, reduction of mercury vapor pressure due to oxidation of mercury, etc. Can be mentioned. Since these brightness attenuation factors are greatly affected by the residual impure gas during lamp manufacturing and the impure gas generated during lighting, the heating temperature should be as high as possible in the exhaust process during manufacturing to reduce residual impure gas. is doing.

However, when the arc tube is formed of lead glass,
Since the softening point is low, the heat treatment temperature can only be raised to about 400 ° C., and sodium and lead, which are the components of lead glass, react with the phosphor and mercury. Therefore, the above-described brightness attenuation factor is promoted, and the brightness is attenuated in a short time.
The required brightness may not be satisfied in a short lighting time.

Therefore, an object of the present invention is to provide a compact fluorescent lamp capable of suppressing cracks and slow leaks in the hermetically sealed portion and also suppressing attenuation of brightness.

[0012]

In order to achieve the above object, the small fluorescent lamp of the present invention uses tungsten as a lead wire constituting an airtight seal portion, and a predetermined area of the pair of lead wires is in an unoxidized state. A glass winding part of borosilicate glass is provided, and the space between the glass winding parts is sealed with an arc tube made of borosilicate glass and having an inner diameter of 10 mm or less.

[0013]

[Function] Since the thermal expansion coefficients of borosilicate glass and tungsten are very close to each other, the borosilicate glass can be directly sealed without oxidation to the tungsten without using a buffer material such as the Dumet wire with a copper film. In this non-oxidizing sealing method, tungsten and borosilicate glass are physically and airtightly bonded, so compared with the above-mentioned oxide film sealing method in which the lead glass and Dumet wire are chemically bonded with the oxide film as an intermediate. The process management is extremely simple and there are few management items.
In other words, it can be reliably sealed without strict process control, and since borosilicate glass (hard glass) is resistant to thermal shock and has a high strain point temperature, there is little residual strain, and cracks and slow leaks in the seal part occur. Can be suppressed.

Borosilicate glass has a lower sodium content than lead glass and does not contain lead at all, so it rarely reacts with phosphors and mercury, and has a high softening point to increase the heat treatment temperature. Therefore, the amount of impure gas remaining can be reduced, and the attenuation of brightness can be suppressed.

[0015]

EXAMPLE FIG. 1 shows, for example, that power consumption is 2 W and rated voltage is 1.
It is a small fluorescent lamp of a semi-hot electrode type with a high brightness, which is 00V and a rated current of 20 mA, and is used as a backlight of a laptop type or a book type personal computer, a liquid crystal panel of a word processor, and is lit with a high frequency power of 50 kHz.
The arc tube 1 has an inner diameter of 10 mm or less, for example 3 mm, and an overall length of 1
It is made of 00 mm borosilicate glass and has a three-wavelength phosphor layer attached to its inner surface. Argon gas is enclosed in the arc tube 1 as a rare gas for starting, together with a small amount of mercury, but the rare gas enclosure gas pressure is 30 to 100 To.
It is rr. Lead wires 2 extend from both ends of the arc tube 1, respectively, and a pair of electrodes 4 connected to the lead wires 2 are arranged to face each other at both inner ends of the arc tube 1. And
The distance between the electrodes 4 and 4 is 80 mm.

2 and 3 are explanatory views of the manufacturing process of the electrode assembly, the lead wire 2 has an outer diameter of 0.3 to 0.
8mmφ tungsten wire 21 and outer diameter is 0.6 ~ 1.0mm
The φ nickel wire 22 is connected at the weld 23. Then, a glass winding portion 3 of borosilicate glass having a coefficient of thermal expansion extremely close to that of tungsten is formed on the outer circumference of the tungsten wire 21 by an oxidation-free sealing method.
First, the surface of the tungsten wire 21 is degreased and then heated in a non-oxidizing atmosphere with a heater to weld borosilicate glass. As a result, the glass winding part 3 and the tungsten wire 2
1 physically adheres airtightly.

That is, in the conventional oxidation sealing method using Dumet wire and lead glass, the surface of the Dumet wire is oxidized and then glass winding is performed by burner heating, followed by annealing to use the oxide film as an intermediate and lead. Although the glass and Dumet wire were chemically bonded, the non-oxidizing sealing method used in the present invention has a simpler process than the conventional oxidation sealing method and is a physical adhesive, so it is sure to be airtight. Can be glued in a state.

The glass winding portion 3 has a length L of 2 to 5 mm and an outer diameter of about 1.1 to 2.5 mmφ.
The relationship between the length L and the outer diameter d of the tungsten wire 21 is important, and is preferably about 0.2 ≦ L / d ≦ 20. L /
When d is smaller than 0.2, that is, when the length L of the glass winding portion 3 is too short as compared with the outer diameter d of the tungsten wire 21, the adhesive strength becomes weak and slow leak may occur. On the other hand, when L / d is greater than 20, the adhesive strength is strong and there is no problem of slow leak, but the effective light emission length is shortened by that much, so L / d ≦ 20 should be set.

Next, the mercury-containing alloy 5 and the electrode 4 are attached to the tungsten wire 21. The mercury-introduced alloy 5 is one in which a mercury compound, such as a Ti-Hg alloy, is attached to one surface of a nickel alloy plate, and a getter material made of, for example, a Zr-Al alloy is baked on the other surface, and after assembly, When heated, the mercury compound releases mercury into the arc tube 1 and the getter material also has a function of absorbing impure gas generated in the arc tube 1 during lighting.

The electrode 4 is of a semi-hot type. For example, the rear end portion 41a of a metal pipe 41 made of stainless steel having an inner diameter of 1.2 mmφ and a length of 5 mm is flatly crushed and the end portion of the tungsten wire 21 is The filament coil 42 and the coil lead portion 43 extending rearward are sandwiched and fixed. These fixing methods may be spot welding. The tip of the filament coil 42 is arranged at a position retracted by about 1 mm from the tip opening 41b of the metal pipe 41.

The filament coil 42 is coated with, for example, (Ba.Sr.Ca) O as an emitter. The filament coil 42 is, for example, a tungsten wire having a wire diameter of about 30 μm wound around a double coil having an outer diameter of 1.0 mm, and the weight thereof is about 3 mg and the length is 2.5 to 3.0 mm. Is. As described above, since the filament diameter is small, the coil lead portion 43 cannot support the filament coil 42, and the filament coil 42 is supported so as to lean against the inner wall of the metal pipe 41. The electrode 4 is not limited to the semi-hot type and may be, for example, a cold cathode type.

When such an electrode assembly is completed, as shown in FIG. 4, the end portion of the arc tube 1 is welded to the glass winding portion 3 and sealed, and then an annealing treatment is performed. Then, a small fluorescent lamp is completed through a step of exhausting the inside of the arc tube, a step of heating a mercury-introduced alloy, and a step of soldering lead wires. At this time, since both the glass winding portion 3 and the arc tube 1 are made of borosilicate glass (hard glass), it is sufficient to sufficiently melt the glass winding portion 3 and the arc tube 1 to improve the familiarity. Incidentally, when sealing lead glass (soft glass) and dumet wire as in the prior art, it is necessary to strictly control the baking temperature and time, and also control the copper oxide film. Therefore, the glass winding portion 3 and the arc tube 1 can be reliably welded, and
Since the tungsten wire 21 and the glass winding portion 3 are securely bonded, the airtight seal portion can be completely sealed and slow leak can be suppressed. Further, since the residual strain in the hermetically sealed portion becomes much smaller and the borosilicate glass is resistant to thermal shock, it is possible to suppress the occurrence of cracks in a heating process such as exhausting or soldering in a subsequent process.

Next, a lighting test of the small fluorescent lamp of the present invention was conducted. The main specifications of the actually manufactured fluorescent lamp are as follows. Arc tube inner diameter 3.0 mm φ Arc tube total length 100 mm Electrode distance 80 mm Noble gas filling pressure 50 Torr Power consumption 2.0 W Discharge current 20 mA Also, as a conventional example, the specifications are the same as the above, using Dumet wire for the lead wire, The same lighting test was performed on a small fluorescent lamp of the oxidation seal type whose arc tube was made of lead glass.

FIG. 5 shows the result of the lighting test. With the lamp of this embodiment, the brightness at the center of the arc tube was about 1 after 15,000 hours of lighting.
It was attenuated by 0%. On the other hand, the lamp of the conventional example is attenuated by about 20% in the same lighting time. Incidentally, the lamp life of a small fluorescent lamp used as a backlight of a liquid crystal display device such as a word processor is said to be a lighting time when the light quantity is reduced to 80% of the initial light quantity, and according to the present invention, the lamp life is remarkably long. It turns out that it is over 15000 hours.

This is because the small fluorescent lamp of the present invention uses borosilicate glass for the arc tube and seals it in a non-oxidized state, so that the processing temperature can be raised in the step of exhausting the arc tube. This is because the residual impure gas is reduced, but the borosilicate glass has a sodium content of 4.4% and a lead content of 0% (the lead glass has a sodium content of 4%). 6.8%, lead content 2
This is because these metal elements are extremely less likely to react with the phosphor and mercury, and it is difficult to promote the factor of brightness attenuation during the travel.

[0026]

As described above, in the compact fluorescent lamp of the present invention, tungsten is used as the lead wire forming the hermetically sealed portion, and the borosilicate glass glass in a non-oxidized state is provided in a predetermined area of the pair of lead wires. Since the winding parts are provided and the space between the glass winding parts is sealed by the arc tube made of borosilicate glass and having an inner diameter of 10 mm or less, it is possible to suppress cracks and slow leaks of the airtight seal part and also suppress the attenuation of brightness. Small fluorescent lamp.

[Brief description of drawings]

FIG. 1 is a front view of a small fluorescent lamp.

FIG. 2 is an explanatory diagram of a manufacturing process.

FIG. 3 is a perspective view of an electrode assembly.

FIG. 4 is a sectional view of an essential part of an embodiment of the present invention.

FIG. 5 is an explanatory diagram of data.

[Explanation of symbols]

 1 Arc tube 2 Lead wire 21 Tungsten wire 22 Nickel wire 3 Glass winding part 4 Electrode 5 Mercury introduction alloy

 ─────────────────────────────────────────────────── (72) Inventor Hirohisa Ishikawa 1194 Sado, Bessho-cho, Himeji-shi, Hyogo Ushio Denki Co., Ltd. Within

Claims (1)

[Claims] 1. A tungsten wire is used as a lead wire constituting an airtight seal portion, and a glass winding portion of borosilicate glass is provided in a predetermined area of the pair of lead wires in a non-oxidized state, and a borosilicate glass portion is provided between the glass winding portions. A compact fluorescent lamp characterized by being sealed by a light emitting tube having an inner diameter of 10 mm or less.