JPH04212239A - Manufacture of discharge lamp - Google Patents

Abstract

PURPOSE:To ensure sealing by inserting a wells having an electrode attached thereto into a glass bulb and temporarily sealing by pinching and then melting by heat the bulb on the opposite side to the electrode from the temporarily- sealed portion and then regularly sealing the wells to the bulb. CONSTITUTION:A wells 4 with an electrode 3 attached thereto is inserted into the end portion of a glass bulb 2 and its inner air is discharged and then a predetermined gas is enclosed therein. Nextly, the sealed portion of the bulb 2 is melted by heat with the wells 4 being held to form a temporarily-sealed portion 2b by pinching, so that the wells 4 is temporarily sealed. And then the pressure inside the bulb 2 on the opposite side to the electrode 3 from the temporarily-sealed portion 2b is reduced and the bulb 2 is melted by heat to regularly seal the wells 4 to the bulb 2. After that, the regularly-sealed portion 2a is pinched to regulate the shape thereof and the unnecessary part of the air-discharging side of the bulb 2 is out off by mold. Thus, the sealing process is performed by two steps, so that the sealing may be ensured and at the same time manufacture thereof may be facilitated.

Description

[Detailed description of the invention]

0001 [Purpose of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a discharge lamp in which a well with electrodes attached is attached to the end of a glass bulb.

0003

2. Description of the Related Art In recent years, discharge lamps such as fluorescent lamps have been used as backlights for liquid crystals. When a discharge lamp is used as the backlight, it is desired that the discharge lamp be thinner, shorter, and have high brightness and a long emission length.

However, conventional discharge lamps have an exhaust pipe at the end, and the sealed cut portion of this exhaust pipe protrudes from the glass bulb, creating a dead space when used as a backlight for a liquid crystal display. Put it away.

[0005] Therefore, a discharge lamp that does not require an exhaust pipe has been proposed.

First, there is a discharge lamp in which glass beads are attached to a well in advance and the ends of the glass bulb and the glass beads are welded and sealed.

However, if glass beads are used, they cannot be formed at low cost, and the size of the sealing portion of the glass bulb is determined by the glass beads.

There is also a discharge lamp in which a frit glass is attached to a metal member that closes the end of a glass bulb, and the frit glass is welded to the metal member for sealing.

However, in this case, since it is difficult to perform evacuation, the welding process must generally be performed in a vacuum, and the process of dealing with gases etc. generated during frit glass welding becomes very complicated.

0010

However, as described above, when glass beads are used, it is not possible to reduce the cost because glass beads are not cheap, and the size of the sealing portion is also restricted by the glass beads.

[0011] On the other hand, in the case of sealing with frit glass, there is a problem that manufacturing processes such as gas treatment are complicated.

Furthermore, it has been considered to attach the well directly to the glass bulb, but if the well is simply welded to the glass bulb using the conventional method, problems with sealing etc. will occur.

The present invention was made in view of the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a discharge lamp that can be made smaller and easier to manufacture.

[0014] [Structure of the invention]

[0015]

Means for Solving the Problems The method for manufacturing a discharge lamp according to claim 1 is a method for manufacturing a discharge lamp in which a well on which an electrode is attached is sealed to an end of a glass bulb. After the electrode is inserted into the end of the glass bulb and the glass bulb is evacuated and filled with a predetermined gas, the glass bulb is sealed while supporting the well. The well is temporarily sealed to the glass bulb by heating and melting the planned part and pinching it, and then the inside of the glass bulb on the opposite side from the electrode from the temporary sealing part where the glass bulb is temporarily sealed. Under reduced pressure, the glass bulb on the opposite side to the electrode is further heated and melted to permanently seal the glass bulb and the well.

The method for manufacturing a discharge lamp according to claim 2 comprises:
In the method for manufacturing a discharge lamp according to claim 1, the pressure ratio between the internal pressure of the glass bulb and the external pressure is 1/40 to less than 1.

[0017]

[Operation] The method of manufacturing a discharge lamp according to claim 1 includes inserting a well to which an electrode is attached into an end of a glass bulb, evacuating the inside of the glass bulb, and filling it with a predetermined gas.
While supporting the well, the portion of the glass bulb to be sealed is heated and melted and pinched to temporarily seal the well to the glass bulb. After that, while reducing the pressure inside the glass bulb on the side opposite to the electrode from the temporary sealing part where the glass bulb is temporarily sealed, the glass bulb on the opposite side to the electrode is heated and melted from this temporary sealing part to form a well. Seal it onto the glass bulb. That is, since the sealing process is performed in two stages, sealing is ensured and leaks are less likely to occur. In particular, since the permanently sealed part of the glass bulb is outside the temporary sealing part, impurity gas generated by melting and heating the glass bulb during the final sealing can cross the temporary sealing part and cause the glass bulb to melt. prevent intrusion into the interior.

The method for manufacturing a discharge lamp according to claim 2 comprises:
In the method for manufacturing a discharge lamp according to claim 1, since the ratio of the internal pressure to the external pressure is 1/40 to less than 1, the molten glass bulb is naturally sealed due to the pressure difference between the internal pressure and the external pressure. This prevents air bubbles from remaining in the sealed portion of the glass bulb.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a low-pressure discharge lamp;
In this discharge lamp 1, a nickel well 4 to which a Gemedes electrode 3 is welded is attached to one end of a glass bulb 2 whose inner surface is coated with a phosphor coating by a two-step sealing process. . Further, a well 4 is similarly attached to the other end (not shown) of the glass bulb 2.

Next, the manufacturing method of the above embodiment will be explained.

First, on the inner surface of a tubular glass bulb 2 that is open at both ends, a phosphor material is applied uniformly in a two-layer coating by turning the glass bulb 2 vertically and turning it upside down using a blow-up method or the like. The body material is dried while rotating the glass bulb 2. Then, it is completely melted and baked at 556° C. to form a phosphor film and prevent impurity gas from remaining.

Next, the Gemedes electrode 3 and the nickel well 4 are welded together. Note that the electrode 3 at one end and the electrode at the other end may have different sizes.

A method for sealing the well 4 to the glass bulb 2 will be described below. The well 4 at the other end of the glass bulb 2 on the side opposite to the exhaust side is sealed to the end of the glass bulb 2 by forming a sealing part by one-time pinch sealing or burning.

Next, the exhaust side of the glass bulb 2 will be explained.

First, the glass bulb 2 is attached to the sealing device 11 shown in FIG. In this sealing device 11, an exhaust pipe 12 is connected to an exhaust part (not shown), and a mounting part 13 for attaching the glass bulb 2 is formed in communication with the exhaust pipe 12. 14 is installed. At approximately the center above the mounting portion 13, a well 4 is provided.
A well holding portion 15 is formed to suspend and hold the.

Then, as shown in FIG. 2, after evacuating the glass bulb 2 and filling it with a predetermined gas, the electrode 3
The glass bulb 2 around the well 4 near the well 4 is heated and melted, and then pinched to form a temporarily sealed portion 2b. This places the well 4 at one end of the glass bulb 2.
is temporarily sealed. Next, the glass bulb 2 on the side opposite to the electrode 3 is successively heated and melted with the temporary sealing portion 2b as the center. The inside of this heated and melted glass bulb 2 is
Since it is connected to the exhaust pipe 12, the pressure is below atmospheric pressure, so that the glass bulb 2 is melted and fused to the well 4 as shown in FIG. As a result of this fusion, the length of the glass bulb 2 in the longitudinal direction as a sealed portion where the glass bulb 2 and the well 4 are reliably fused becomes a sufficient length of 3 mm or more.

After the molten glass of the glass bulb 2 is sufficiently adapted to the well 4, the main sealing part 2a is pinched again using the mold that regulates the sealing part to regulate the shape of the sealing part. An unnecessary part on the exhaust side of the glass bulb 2 is cut off using a mold.

After this, aging is performed to complete the discharge lamp 1.

According to the above embodiment, since the sealing process is carried out in two stages, sealing is ensured, and furthermore,
By setting the length of the sealed portion in the longitudinal direction of the glass bulb 2 to 3 mm or more, the occurrence of leakage is reduced. In particular, since the main sealing position is outside the temporary sealing position, impurity gas generated by melting and heating the glass bulb 2 during the main sealing to form the main sealing part 2a crosses the temporary sealing part 2b. Intrusion into the valve 2 can be prevented. Further, according to the above embodiment, when the outside pressure is atmospheric pressure (760 Torr), the air pressure of the glass bulb 2 is as shown in FIG.
It is about 6 Torr to 150 Torr. That is, if it is 76 Torr or less, leakage will easily occur due to the molten glass bulb 2 being sucked into the glass bulb 2 during temporary sealing.
If it exceeds this, air bubbles remain in the sealed portions such as the permanent sealed portion 2a or the temporary sealed portion 2b, and the well 4 tends to be insufficiently welded to the glass bulb 2. Therefore, if the pressure is about 76 Torr to 150 Torr, it is possible to manufacture the discharge lamp 1 that is less prone to leakage defects.

[0031] Furthermore, by changing the external pressure, if the ratio with the internal pressure is about 1/40 to less than 1, it is possible to prevent leakage defects from occurring.

Furthermore, during the actual sealing, it is not necessarily necessary to shape the shape of the sealed part by pinching using a mold, and unnecessary portions of the glass bulb 2 may also be cut by burning off, regardless of the mold. .

[0033]

According to the method for manufacturing a discharge lamp according to claim 1, a well with an electrode attached is inserted into the end of a glass bulb, the glass bulb is temporarily sealed by pinching from above the well, and then the glass bulb is temporarily sealed. With the pressure inside the glass bulb on the opposite side of the electrode reduced from the temporary sealing part where the bulb was temporarily sealed,
Subsequently, the glass bulb on the opposite side of the electrode is melted and heated from this temporary sealing part to permanently seal the well to the glass bulb.The sealing process is divided into two stages, so sealing can be ensured, and It can prevent impure gas from entering the glass bulb, it can be downsized, and it can be easily manufactured.

According to the method for manufacturing a discharge lamp according to claim 2, in addition to the method for manufacturing a discharge lamp according to claim 1, the ratio between the internal pressure and the external pressure of the glass bulb is from 1/40 to less than 1. As a result, leakage of the discharge lamp can be made less likely to occur.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a glass bulb after main sealing is performed, showing one step of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the glass bulb after temporary sealing, showing one step of the same as above.

FIG. 3 is a sectional view of a glass bulb after unnecessary glass bulbs are cut, showing one step of an embodiment of the present invention.

FIG. 4 is a cross-sectional view when a discharge lamp is connected to the above sealing device.

FIG. 5 is a graph showing the relationship between sealed gas pressure and leak failure.

[Explanation of symbols]

1 Discharge lamp 2 Glass bulb 2a　　　　　　　Sealing part 2b Temporary sealing part 3 Electrode 4 Wells

Claims (2)

[Claims] 1. A method for manufacturing a discharge lamp in which a well with an electrode attached is sealed to an end of a glass bulb, wherein the well with an electrode attached is inserted into the end of the glass bulb and the electrode is sealed to the end of the glass bulb. After evacuating the inside of the glass bulb and filling it with a predetermined gas, the well is heated and melted and pinched while supporting the well. Temporarily seal the glass bulb to a glass bulb, and then, with the pressure inside the glass bulb on the side opposite to the electrode being reduced from the temporary sealing part where the glass bulb is temporarily sealed, the glass bulb on the side opposite to the electrode is removed. A method for manufacturing a discharge lamp, which further comprises heating and melting to permanently seal the glass bulb and the well. 2. The method for manufacturing a discharge lamp according to claim 1, wherein the pressure ratio between the internal pressure and the external pressure of the glass bulb is 1/40 to less than 1.