JPH04167331A - Method of sealing chipless type fluorescent lamp - Google Patents

Abstract

PURPOSE:To keep rare gas high in purity by supplying a valve with mercury in an amalgam state or a mercury-containing state through a discharge hole, supplying the hole with a glass bond, and heating the bond to seal the hole CONSTITUTION:When rare gas at prescribed pressure is filled in a airtight vessel 30, the gas is infected through a discharge hole 20 so that it is also filled in a bulb 5 at the same pressure. In this state, a mercury throwing-in device 35 is shifted onto a hole 20 to throw amalgam 38 or a mercury-containing substance from the hole 20 into the bulb 5. After that, the device 35 is retreated and a closing glass supply device 36 is shifted onto the hole 20 to supply the hole 20 with a closing glass 21. The device 36 is next retreated for a concentration heating device 37 to irradiate concentratively the glass 21 mounted on the hole 20 and melt it to close the hole 20 and the bulb 5. Impurities exhausted into the bulb 5 is removed the hole 20 later. The impurities exhausted from an electrode 7, etc., cannot be left in space electric discharge.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Industrial Application Field) The present invention provides a chipless fluorescent lamp that is suitable for use in flat fluorescent lamps formed by bonding flat glass pieces together. This invention relates to a method for sealing a lamp.

(Prior art) In general, in various types of lamps, an exhaust pipe is provided protruding from the bulb for the exhaust process or sealing process, and the space inside the bulb is evacuated through this exhaust pipe, or rare gas is filled in. ing. However, this exhaust pipe is sealed off after the sealing process is completed, and a protrusion called a chip remains on the valve wall at the end of the sealing cut. Such protrusions can be a nuisance, and there is a desire to eliminate the tip, especially in small lamps.

However, lamps without exhaust pipes such as those mentioned above,
In other words, in the case of a chipless lamp, exhausting and sealing are difficult.

Recently, research has been conducted on the application of flat fluorescent lamps formed by bonding flat glass pieces to backlights of liquid crystal display devices and color view finders. Since the entire flat light emitting surface emits light relatively uniformly, it is effective for illuminating a predetermined spread area.

This type of flat fluorescent lamp has a pair of flat glasses joined together at their peripheries to form a discharge space between them, or a pair of shallow dish (bowl-shaped) glasses joined together at their peripheries. A discharge space is formed using a glass plate, or a glass plate and a shallow dish glass are bonded together at their peripheries.

A flat fluorescent lamp constructed by bonding a pair of flat glasses will be described with reference to FIGS. 8 and 9.

Reference numeral 1 denotes a flat glass on the front side serving as a light emitting surface, 2 a flat glass on the back side, and 3 a frame-shaped glass spacer provided between these flat glasses 1.2. These pair of flat glasses 1.2 are integrally joined at their peripheral edges with a glass adhesive 4.4 with the frame-shaped spacer 3 interposed therebetween. As a result, a bulb 5 is constructed by these members, and a discharge space 6 is formed within this bulb 5.

Cold cathodes 7.7 are arranged facing each other in such a discharge space 6, and these cold cathodes 7.7 are made of, for example, a nickel plate in the shape of a rectangular strip. These power supply terminal pieces 8.8 are hermetically sealed to the joint surface of the flat glass 1 and the spacer 3 and are led out.

Note that the inner surface of the flat glass 1.2 is coated with a phosphor coating 1a.
, 2a are formed.

Since such a flat fluorescent lamp does not have an exhaust pipe, it is sealed by a vacuum evacuation method. This evacuation method uses a vacuum evacuation apparatus shown in FIG. That is, 10 has an airtight container 10 used for the vacuum evacuation method, and a heating table 11 is installed inside this airtight container 10. This heating table 11
is heated by, for example, a carbon heater 12.

Further, the airtight container 10 is connected to a vacuum pump 15 and a rare gas supply cylinder 16 such as argon via on-off valves 13 and 14.

A method of sealing the flat fluorescent lamp using such a vacuum evacuation device will be described.

One flat glass 2 (or 1) is placed on the heating table 11, a frame-shaped solid glass adhesive 4 is placed on the peripheral edge of the flat glass 2, and the glass frame A spacer 3 is placed, and another frame-shaped solid glass adhesive 4 is placed on top of this, and the other flat glass 1 (or 2) is placed on top of this. At this time, the electrode 7.7 is placed at the predetermined position shown in the figure, and the mercury alloy 9 is previously attached to the electrode 7.7 by means such as spot welding.

In such a polymerized state, the on-off valve 13 is opened and the vacuum pump 1 is turned on.
5, the airtight container 10 is evacuated.

This exhaust air causes the unsealed flat glass l
The space between and 2 is evacuated at the same time.

When the inside of the container 10 reaches a predetermined degree of vacuum, the on-off valve 13 is closed, the other exhaust valve 14 is opened, and a rare gas such as argon is supplied into the container 10 from the rare gas supply cylinder 16.

When the rare gas in the container 10 reaches a predetermined pressure, the space between the flat glasses 1 and 2, which is not yet sealed at this stage, is also filled with the rare gas at a predetermined pressure.

In this state, the unfinished lamp in the polymerized state is heated through the heating table 11.

This heat is transferred to the solid glass adhesives 4.4 superimposed on the glass frame-shaped spacer 3, and these glass adhesives 4.4 are heated. For this reason, solid glass adhesive 4.
4 is melted, and the molten glass adhesive 4.4 wets the glass frame-shaped spacer 3 and the flat glasses 1 and 2 stacked one above the other, and the spacer 3 and the flat glasses 1 are bonded together.
and 2 are hermetically joined together.

In this case, the power supply terminal piece 8 joined to the cold cathode 7.7
．． 8 is hermetically sealed to the joint surface of the flat glass 2 and the spacer 3.

The discharge space 6 is hermetically sealed by such bonding.

(Problem to be Solved by the Invention) However, in the above sealing method, exhaust gas and rare gas supply are performed through the gaps between the stacked glass members and the adhesive, so these are not sealed. These gaps in koji are also small, making it difficult for air and rare gases to flow.
Exhaust and rare gas supply efficiency is poor.

In addition, after evacuation, the glass adhesive 4.4 is sealed by heating and melting the glass adhesive 4.4 while filling the space between the flat glasses 1 and 2 with rare gas at a predetermined pressure. During the heating process, the impurities that were attached to and occluded in the glass adhesive 4.4 are released, and the impurities that were attached to and occluded on the flat glass 1.2, the spacer 3, and the cold cathode 7.7 are also released by heating. It is released and mixed into the rare gas in the discharge space 6. The release of such impurities increases as the bonding progresses, that is, as the sealing progresses, the release of impurities increases and it becomes impossible for the impurities to escape.

Therefore, the purity of the rare gas in the discharge space 6 is significantly reduced,
The lamp's starting characteristics and luminous efficiency will deteriorate, and its life will be shortened.

In addition, after the above-mentioned sealing, such a lamp heats the mercury alloy 9 from the outside of the lamp to evaporate it, and the discharge space 6 is heated.
A method of supplying this material is adopted. In order to heat the mercury alloy 9, a method has been considered in which, for example, a high frequency magnetic field is generated using a high frequency induction heating coil, and the mercury alloy 9 is heated by the lines of magnetic force.

However, in such heating, the mercury alloy 9
The heat that heats the glass is transmitted through the power supply terminal piece 8 connected to the electrode 7 and is conducted to the glass adhesive 4 that joins the flat glass 1 and the spacer 3, causing thermal stress in the glass adhesive and causing cracks. This may cause such problems to occur.

The present invention was developed based on these circumstances, and its purpose is to maintain high purity of rare gas without leaving any impurities in the discharge space, and to eliminate the need to heat the electrodes to release mercury. Therefore, it is an object of the present invention to provide a method for sealing a chipless fluorescent lamp that can prevent problems such as heat damage to the sealed portion through the power supply terminal member.

[Structure of the Invention] (Means for Solving the Problems) The present invention is characterized in that an electrode is sealed in advance in a bulb having an exhaust hole formed in the side wall avoiding the effective light emitting surface, and the bulb is housed in an airtight container. , evacuating the inside of the valve through the exhaust hole by evacuating the airtight container, then supplying rare gas to the airtight container and supplying the rare gas into the valve through the exhaust hole; mercury is supplied through the exhaust hole, glass adhesive is supplied to the exhaust hole, and the glass adhesive is heated and melted to seal the exhaust hole with the glass adhesive. shall be.

(Function) According to the present invention, the valve is manufactured and the electrodes are sealed in advance in the air or an inert gas atmosphere, and the exhaust and rare gas are supplied through the exhaust hole formed in the valve in an airtight container. Then, add mercury, supply glass adhesive to the exhaust hole in this airtight container, melt this glass adhesive by heating intensively, and seal the exhaust hole with this glass adhesive. Therefore, impurities released from the glass, adhesive, electrodes, etc. due to heating during bulb manufacturing do not remain in the discharge space.

In addition, since mercury is supplied into the bulb in the form of an amalgam or inclusion, no special heating process is required after sealing, and the electrode is heated and the heat is transmitted to the sealed part via the power supply terminal member. This prevents the occurrence of cracks.

(Example) The present invention will be described below based on a first example shown in FIGS. 1 to 5.

1 and 2 show the structure of a planar fluorescent lamp, and in this embodiment, the structure may be similar to the lamp shown in FIGS. 8 and 9, so the members are the same as those shown in FIG. The members will be explained using the same numbers.

This embodiment is different from the lamps shown in FIGS. 8 and 9 in that an exhaust hole 20 is formed on one side of a frame-shaped spacer 3 made of glass, for example, avoiding the area that becomes the effective light emitting surface. This exhaust hole 20 is finally sealed with a closing glass 21, as shown by the imaginary line in FIG.

This sealing method will be explained based on the drawings shown in the order of steps shown in FIGS. 3 to 5.

First, the valve 5 is assembled in advance in the air or in an inert gas atmosphere.

This may be done in the same manner as in the past using the heating table 11 shown in FIG. 10 or the like.

In this case, an exhaust hole 20 is provided on one side of the glass frame-shaped spacer 3.
Therefore, even if impurities are released from the flat glasses 1 and 2, the glass frame spacer 3, the electrode 7, etc., which are bonded by the molten glass adhesive 4.4, these impurities will be removed from the exhaust hole later. It can be discharged through 20.

The bulb 5 that has been joined in this way is housed in the sealing device shown in FIGS. 3 and below.

The sealing device includes an airtight container 30, which is connected via on-off valves 31, 32 to a vacuum pump 33 and a rare gas supply cylinder 34 such as argon.

The airtight device 30 includes a mercury dropping device 35, a closing glass supply device 36, and a central heating device 37 for closing glass.

The valve 5, which has been preassembled externally as described above, is housed in the airtight container 30, and is placed in a position where the exhaust hole 20 faces the central heating device 37, as shown in FIG.

The on-off valve 31 is opened and the airtight container 30 is evacuated by the vacuum pump 33. Due to this exhaust, the air inside the airtight container 30 is exhausted, and at the same time, the air inside the valve 5 is also exhausted through the exhaust hole 20.
Exhausted through. At this time, impurities remaining in the valve 5 are also removed.

When the airtight container 30 and the valve 5 reach a predetermined degree of vacuum, the on-off valve 31 is closed, the other exhaust valve 32 is opened, and a rare gas such as argon is supplied from the rare gas supply cylinder 34 into the container 30.

When the airtight container 30 is filled with rare gas at a predetermined pressure, this rare gas enters through the exhaust hole 20, so that the valve 5 is also filled with rare gas at the same pressure.

In this state, as shown in FIG.
5 in the direction of the arrow, and the amalgam 38 or mercury-containing material is introduced from the mercury dispensing device W35.

The amalgam is B1-Pb-In-Hg, and the mercury-containing body is a porous ceramic containing a predetermined amount of mercury.

Note that instead of amalgam or a mercury-containing material, a form of mercury that turns into mercury vapor when the lamp is lit for the first time without being heated again may be used.

Such amalgam 38 and mercury-containing material are dropped into the valve 5 from the exhaust hole 20.

Next, as shown in FIG. 4, the mercury dropping device 35 retreats, and the closing glass supplying device 36 moves forward in its place as shown by the arrow, and this closing glass supplying device 36 supplies the closing glass 21 to the exhaust hole 20. do. This closes the exhaust hole 20.

The closing glass 21 is made of a solid glass adhesive, and the glass adhesive 4.0 used for joining the flat glasses 1 and 2 and the glass frame-shaped spacer 3.
It is desirable that the melting point is lower than that of 4.

For example, the melting point of the glass adhesive 4.4 is about 600°C, while the melting point of the closing glass 21 is about 450°C.

When the supply of the closing glass 21 is finished in this way, the fifth
As shown in the figure, the closing glass supply device 36 is retracted and the central heating device 37 is activated.

Although not shown in detail, the concentrated heating device 37 directs heat generated from a heat generating source to the exhaust hole 2 using a condensing device such as a reflecting mirror or a lens.
The occluding glass 21 placed on the holder is irradiated intensively, thereby melting the occluding glass 21.

Therefore, due to the melting of this blocking glass 21, the exhaust hole 2
0 is hermetically closed, and the valve 5 is sealed.

According to such a sealing method, since the lamp does not have a special exhaust tip, there is no protrusion that gets in the way, and there is no problem in downsizing the lamp.

In the above method, the assembly, bonding, and electrode sealing of the bulb 5 are performed in advance in the atmosphere or an inert gas, so this work is easy to perform. can be excluded from.

Then, such a valve 5 is housed in an airtight container 30 to perform exhaust and supply of rare gas, and in this case, the exhaust hole 20
Since gas can enter and exit through the tank, good exhaust and rare gas filling can be performed.

Since the exhaust hole 20 is closed with a closing glass 21 made of glass adhesive, the bulb 5 is sealed with this closing glass 21.

In this case, since the closing glass 21 made of glass adhesive is melted by local concentrated heating, there is no need to cause unnecessary thermal distortion to the bulb 5, and there is no need to worry about the heat for melting heating and evaporating the mercury put in. There isn't.

Therefore, the amount of mercury enclosed can be regulated with high precision.
It is also easy to control the amount of inclusion.

Since mercury is supplied into the bulb 5 in the form of an amalgam 38 or an inclusion, no special heating process is required after sealing, and the electrode 7 is heated and the heat is transferred to the power supply terminal member 8.
The cracks will not be transmitted to the sealed portion through the cracks, thereby preventing the occurrence of cracks.

Note that the present invention is not limited to the above embodiments.

That is, in the above embodiment, a case has been described in which the flat fluorescent lamp is composed of a pair of flat glasses 1 and 2 and a frame-shaped spacer 3 inserted between them. As shown in the second embodiment shown in FIG.
You may use the bulb of the structure which consists of 0 and 0, and these are joined with the glass adhesive 4. In this case, the exhaust hole 20 may be formed in the rising wall 41 of the shallow dish-shaped glass 40.

Further, the present invention has a structure in which a flat fluorescent lamp is constructed with a pair of shallow glass glasses 40 and 40, and these are bonded together using a glass adhesive 4, as shown in a third embodiment shown in FIG. A valve may also be used. In this case as well, the exhaust hole 20 may be formed in the rising wall 41 of the shallow dish-shaped glass 40, extending over one or both sides.

The present invention is not limited to flat fluorescent lamps, but can be applied to lamps without exhaust pipes.

Therefore, the electrode is not limited to a cold cathode, but may also be a hot cathode.

Furthermore, during the evacuation step, the glass member or the electrode member may be heated and evacuation may be performed in order to actively remove impurities occluded in the glass member or electrode member.

[Effects of the Invention] As explained above, according to the method of the present invention, a bulb is manufactured and an electrode is sealed in advance in the air or an inert gas atmosphere, and the bulb is formed in an airtight container. The glass adhesive is supplied to the exhaust hole in this airtight container, and the glass adhesive is melted by intensive heating. Since the exhaust hole is sealed with this glass adhesive, impurities released from the glass, adhesive, electrodes, etc. due to heating during bulb manufacturing will not remain in the discharge space. Therefore, the purity of the rare gas sealed in the discharge space is maintained high, and the starting characteristics, luminous efficiency, and life characteristics are improved. In addition, since mercury is supplied into the bulb in the form of an amalgam or inclusion, no special heating process is required after sealing, and the electrode is heated and the heat is transmitted to the sealed part via the power supply terminal member. This prevents the occurrence of cracks.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a flat fluorescent lamp showing a first embodiment of the present invention, FIG. 2 is a sectional view of the main parts of the assembled state, and FIGS. 3 to 5 are sealed FIG. 6 is an exploded perspective view of a flat fluorescent lamp showing a second embodiment of the present invention, and FIG. 7 is a diagram showing a third embodiment of the present invention. FIG. 8 is an exploded perspective view of a conventional flat fluorescent lamp, FIG. 9 is a sectional view of the main parts of the assembled state, and FIG. The figure is a configuration diagram of a sealing device for explaining a conventional sealing process. 1.2...Flat glass, 3...Frame spacer,
4...Glass adhesive, 5...Bulb, 6...Discharge space, 7...Cold cathode, 8...Power supply terminal piece, 20...
・Exhaust hole, 21...Closing glass, 30...Airtight container, 31.32...Opening/closing valve, 33.
...Vacuum pump, 34...Rare gas cylinder, 35...
Mercury dropping device, 36...Closing glass supply device, 37.
...central heating device, 38...amalgam. Applicant's Representative Patent Attorney Takehiko Suzue Figure 5 Figure 6 Figure 7 Figure 10 Procedural Amendment Statement March 10, 1998, Order 5

Claims (2)

[Claims] (1) An electrode is sealed in advance in a bulb with an exhaust hole formed in the side wall that avoids the effective light emitting surface, this bulb is housed in an airtight container, and the inside of the bulb is evacuated through the exhaust hole by evacuating the airtight container. and then supplying a rare gas to the airtight container and supplying the rare gas into the valve through the exhaust hole,
In addition, mercury is supplied in the form of an amalgam or an inclusion into the bulb through the exhaust hole, and a glass adhesive is supplied to the exhaust hole, and the glass adhesive is heated and melted. A method for sealing a chipless fluorescent lamp, comprising closing the exhaust hole. (2) The above-mentioned chipless fluorescent lamp is a flat fluorescent lamp formed by joining a pair of flat glasses, or joining a flat glass and a dish-shaped glass, or joining dish-shaped glasses together. A method for sealing a chipless fluorescent lamp according to claim 1.