JPS63164142A - Manufacture of chipless fluorescent lamp and device therefor - Google Patents

Abstract

PURPOSE:To manufacture a chipless fluorescent lamp in a simple process very easily, and to improve the yield, by heating a holding member with an induction heating in a evacuated outer tube, and melting and sealing a luminous tube and a bead stem held by the holding member. CONSTITUTION:A bead stem 11 is loaded on the center of a recess 61 of a holding member 6 in the condition that two lead wires 12 extended outward from the bead stem 11 are inserted in small holes 62 respectively, and one end 10a of a luminous tube 10 of a small size fluorescent lamp is inserted to a recess 61. After that, an outer tube 2 made of quartz is inserted airtight to a holding table 1, and the inside of the outer tube 2 is evacuated by operated by operating a vacuum pump. Then a current is applied to a high-frequency oscillator to let the high-frequency current flow in a induction coil 7. As a result, an excessive current is induced at the surface of the holding member 6 to heat the holding member 6. When the current is continued to apply further, the temperature of the holding member 6 rises up to 1600 deg.C or higher, and one end 10a of the luminous tube 10 and the bead stem 11 are melted and sealed up. In such a way, a chipless fluorescent lamp can be manufactured in a simple process and in a very easy way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a chipless fluorescent lamp and an apparatus directly used in the manufacturing method.

[Prior art and its problems]

Recently, new products such as pocket televisions have been developed, and the screens of these televisions are formed using liquid crystal elements.

The use of small fluorescent lamps as this backlight has been proposed and put into practical use. In the current state of development of LCD TVs, 2- to 3-inch models are mainstream, and in order to use batteries, the total length of the lamp is less than 120ml, the inner diameter of the luminous tube is less than 51III11, and the power consumption is less than 4W. A small size is required.

In a fluorescent lamp, during discharge, a cathode dark area that does not contribute much to light emission in front of the cathode and a positive column area that effectively emits light are formed between the electrodes. As the total length of the lamp becomes shorter, the electrode spacing also becomes shorter, but the length of the cathode dark area, which does not contribute much to light emission, does not decrease in proportion to the electrode spacing, and therefore the ratio of the effective positive column to the electrode spacing decreases. This results in a decrease in luminous efficiency. For this reason, in small fluorescent lamps.

Minimize the dead space behind the electrode as much as possible.

The ratio of the electrode spacing to the total length of the lamp must be increased.

Incidentally, in a fluorescent lamp, the end of the arc tube is sealed after the inside of the arc tube is evacuated, and a glass plug called a pantum stem is often welded to the end opening of the arc tube to seal it. , an exhaust pipe extends backwards, and after being welded to the opening at the end of the arc tube, exhaust is exhausted from this exhaust pipe, and the exhaust pipe is cut off by melting (chip-off). At this time, the remaining part of the exhaust pipe, called a chip, remain. Therefore,
The problem is that the dead space behind the electrodes inevitably becomes large, and the ratio of the electrode spacing to the total length of the lamp becomes small, resulting in low luminous efficiency. Therefore, if a chipless fluorescent lamp is used, in which there is no remaining portion of the exhaust pipe, the dead space behind the electrodes will become smaller and the luminous efficiency will be improved. Therefore, various methods of manufacturing chipless fluorescent lamps have been attempted, but all of these methods involve complicated processes and low productivity, and also require cutting off the remaining portion of the arc tube outside the sealed portion after sealing. However, there are problems such as low material yield, and the reality is that it has not been put into practical use.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for manufacturing a chipless fluorescent lamp with simple steps and a high material yield, and an apparatus that can be directly used in the manufacturing method.

[Structure of the invention and its effects]

In the manufacturing method of the present invention, an induction coil is provided on the outer periphery of a quartz outer tube whose inside is depressurized, a graphite holding member having a concave portion on the upper surface is arranged inside the outer tube at a position corresponding to the induction coil, and an electrode The bead stem holding the bead stem and the arc tube end of the fluorescent lamp, the other end of which has already been sealed, are inserted into the recess, and while the inside of the outer tube is depressurized, high-frequency or low-frequency current is passed through the coil to close the holding member. It is characterized in that the inside of the arc tube is evacuated by induction heating, and the bead stem is welded and sealed to the end of the arc tube by the heat of the holding member.

In addition, the manufacturing equipment used directly in the manufacturing method of the present invention includes a quartz outer tube that is connected to a pressure reducing machine and hermetically sealed, and a quartz outer tube that is arranged around the outer circumference of this outer tube and connected to a high frequency or low frequency oscillator. It has an induction coil placed inside the outer tube at a position corresponding to the induction coil, and has a bead stem holding an electrode and a recessed part on the top surface into which the end of the fluorescent lamp's arc tube is inserted, and generates heat by induction heating. It is characterized by consisting of a graphite holding member.

In other words, the arc tube is placed inside a quartz outer tube that is connected to a pressure reducer and airtightly sealed, so the inside of the arc tube is also exhausted, but the end of the arc tube, along with the bead stem that does not have an exhaust tube, is The evacuated end of the arc tube is inserted into the four parts formed on the top surface of the graphite holding member, so when the graphite holding member is heated by induction, the bead stem is welded to the end of the arc tube and sealed. Ru. Therefore, a chipless fluorescent lamp without any remaining part of the exhaust pipe can be manufactured very easily through simple steps, and since there is no need to cut the remaining part of the arc tube after sealing, the material yield is also extremely high.

〔Example〕

The present invention will be specifically described below based on embodiments shown in the drawings.

FIG. 1 is a sectional view showing an embodiment of the manufacturing apparatus of the present invention.
An outer tube 2 made of quartz is removably fitted into the tube. This outer tube 2
has a bottomed cylindrical shape with one end closed, and is airtightly fitted with a seal 3, so that when the pressure reducer operates, the pressure inside the outer tube 2 is reduced to about 10<-4> torr. A support bar 4 is erected in the center hole of the holder 1, and a cylindrical holder 5 is fixed to the tip of the support rod 4 and is disposed on the upper part of the holder 1. A plurality of exhaust windows 51 are provided on the peripheral wall of this holder 5.
is formed, and a holding member 6 made of graphite is fitted and held in the upper end hole, but this holding member 6 is
As shown in the figure, a recess 6I is formed on the upper surface, and two pores 62 are bored in the four parts 61. An induction coil 7 connected to a high frequency oscillator (not shown) with an output of 4KW is placed on the outer periphery of the outer tube 2 at a position corresponding to the holding member 6. The holding member 6 is heated by induction and generates heat. Note that a low frequency oscillator may be used instead of the high frequency oscillator, and heat may be generated by low frequency induction heating.

Therefore, as shown in FIG. 2, first, the bead stem 1
The bead stem 11 is placed in the center of the recess 61 of the holding member 6 with the two lead wires 12 extending outward from the holder 6 inserted into the pores 62, and the light emitting tube 10 of the small fluorescent lamp is assembled.
Insert one end 10a into the recess 61. At this time, a slight gap 15 exists between one end 10a of one arc tube 10 and the bead stem 11. Then, the other end 1 of the arc tube 10
0. Place the weight 8 on b to firmly hold the arc tube lO. Here, the other end 10b of the arc tube 10 made of quartz glass is already sealed with a bead stem and a filament electrode is attached, but the total length is 120+
It is a small device with an inner diameter of 511 mm or less and an inner diameter of 511 mm or less, and a fluorescent film is coated on the inner wall surface.

The bead stem 11 is made of spherical quartz glass without an exhaust pipe, etc., and the filament electrode 13 is held by two lead wires 12 made of nickel wire or Kovar wire planted in it. lead a iz
A getter 14 made of mercury alloy is attached to.

The filament constituting the electrode 13 is made of a high melting point metal such as tungsten or molybdenum, and is arranged in the axial direction of the arc tube 10 because the inner diameter of the arc tube 10 is small. The filament can be single or double coiled, but either way it is lightweight.

For example, the weight of the part to which the electron emitter is attached is 0.1
~3.1 mg. This is because the heat capacity decreases due to weight reduction, and even if power consumption is reduced, the temperature rises easily and lighting performance improves.

As the material of the electron emitter, oxides or carbonates of alkali metals or alkaline earth metals, and various other materials are used.

Next, the outer tube 2 made of quartz is airtightly fitted onto the holding table 1, and the pressure reducing machine is operated to reduce the pressure inside the outer tube 2.

At this time, the pressure inside the arc tube 10 is also reduced through the gap 15, the pore 62, and the exhaust window 51. Then, a high-frequency oscillator is energized to send a high-frequency current through the induction coil 7. This induces an eddy current on the surface of the holding member 6 and generates heat, but when the temperature rises to 1000-1200°C, it adheres to the filament electrode 13. The triple carbonate electron emitter thermally decomposes and becomes activated. Since the quartz glass is not yet melted at this temperature, the gas generated by thermal decomposition of the triple carbonate is exhausted through the gap 15.

Therefore, conventionally, the filament electrode 1 is
Although the triple carbonate was activated by applying electricity to and heating the triple carbonate, according to the present invention, this activation step is no longer necessary. When the current is continued, the temperature of the holding member 6 increases to 160℃.
When the temperature is raised to 0° C. or higher, one end 10a of one arc tube 10 and the bead stem 11 are melted and sealed.

In this way, when one end 10a of the arc tube 10 is sealed, a chipless compact fluorescent lamp is completed, and since there is no remaining exhaust pipe behind the bead stem 11, f! ! Although the ratio of the distance between electrodes is increased and the total lamp length is short, the result is a compact fluorescent lamp with high luminous efficiency.The first manufacturing process is greatly simplified, and since induction heating is used, it can be heated in a short time without contact. It can be heated in a short amount of time, significantly improving productivity. Conventionally, the bead stem 11 is placed inside the end of the arc tube 10, and the end of the arc tube 10 is directly connected to a pressure reducing machine to weld the bead stem 11 while reducing the pressure. However, in the present invention, since it is sealed inside the depressurized outer tube 2,
The bead stem 11 can be welded to the extreme end of the arc tube 10.

Therefore, there is no need to cut the remaining part of one arc tube lO, and the material yield is also improved. The apparatus used in the manufacturing method of the present invention can also be made into a very simple 41-piece structure. In addition.

Although this embodiment shows an example in which one arc tube 10 is arranged inside the outer tube 2, productivity can be further improved by arranging a large number of arc tubes IO at the same time. .

〔Effect of the invention〕

As explained above, in the present invention, the holding member is made to generate heat by induction heating within the depressurized outer tube, and the arc tube and bead stem held by the holding member are melted and sealed. To provide a manufacturing method and a manufacturing device that can extremely easily manufacture a light-less fluorescent lamp through a simple process, and can also extremely increase the material yield since there is no need to cut the remainder of one arc tube after sealing. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of section Δ in FIG.

Claims (1)

[Scope of Claims] 1. An induction coil is provided on the outer periphery of a quartz outer tube whose interior is depressurized, and a graphite holding member having a recessed portion on the upper surface is arranged within the outer tube at a position corresponding to the induction coil. The bead stem holding the electrode and the end of the arc tube of the fluorescent lamp, the other end of which is already sealed, are inserted into the recess, and while the inside of the outer tube is depressurized, a high-frequency or low-frequency current is passed through the coil to remove the holding member. 1. A method for manufacturing a chipless fluorescent lamp, comprising the steps of heating the arc tube by induction, evacuating the inside of the arc tube, and welding and sealing the bead stem to the end of the arc tube using the heat of the holding member. 2. A quartz outer tube connected to the pressure reducer and hermetically sealed, an induction coil arranged around the outer circumference of this outer tube and connected to a high-frequency or low-frequency oscillator, and a position corresponding to the induction coil. A chip that is arranged in an outer tube and consists of a bead stem holding an electrode and a graphite holding member that has a concave portion on the top surface into which the end of the arc tube of a fluorescent lamp is inserted, and that generates heat by induction heating. Manufacturing equipment for fluorescent lamps.