JPS585499B2 - How to fill mercury for discharge tubes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a discharge tube, and more particularly to a method for reliably sealing a predetermined amount of mercury into a bulb.

As a conventional method for filling mercury into a discharge tube, for example, a fluorescent discharge tube, there is a method of filling mercury using an exhaust head shown in FIG.

This method will be explained using FIG.

First, the valve exhaust capillary 1 provided on the valve 4 is attached to the insertion port 2 of the exhaust head, and then, after exhausting and removing the impurity gas in the valve 4 through the valve exhaust capillary 1 and the exhaust pipe 3, the mercury The metered dropping device 5 is operated to seal mercury into the valve 4 via the valve exhaust capillary 1.

However, in this conventional method, the amount of mercury measured by the mercury metering/dropping device is not reliably sealed into the bulb, resulting in an increase in the operating voltage of the completed discharge tube,
There were drawbacks such as a decrease in luminous flux value, lifespan, etc.

In other words, the cause of this is that when mercury weighed to a predetermined amount falls into the valve along the valve exhaust capillary, when it comes into contact with the inner circumferential wall of the valve exhaust capillary, the fallen mercury is This was due to all or part of the remaining adhering to the inner circumferential wall of the valve exhaust capillary.

As a method for improving such conventional drawbacks, there is a method in which the inner peripheral wall of the valve exhaust capillary tube is corroded in advance to give it an uneven shape, and a predetermined amount of mercury is sealed in the valve.

This method is an improvement over the conventional method in terms of sealing the intended amount of mercury into the bulb, but it requires work to corrode the inner peripheral wall of the exhaust capillary into an uneven shape in advance, and it is difficult to fabricate a silica charge/discharge tube. There were disadvantages such as increased man-hours.

The present invention eliminates these conventional drawbacks and provides a method for reliably sealing the intended amount of mercury into a bulb.

That is, in the present invention, an oxide powder that does not deteriorate the lamp characteristics even if it is sealed in the discharge tube is attached to the surface of the mercury measured in the amount scheduled to be sealed, and then sealed in the bulb through the bulb exhaust tube. This is the way to do it.

According to the present invention, even if mercury comes into contact with the valve exhaust capillary, the mercury surface is coated with oxide powder, so the adhesion area between the inner circumferential wall of the valve exhaust capillary and the mercury does not sag, and the amount scheduled to be sealed is It is possible to reliably seal mercury inside the valve without adhering it to the inner circumferential wall of the exhaust capillary.

The oxide powder used in the present invention is sealed in a tube together with mercury, but these oxide powders are surface inert and oxygen (02
), carbon dioxide (CO2), water (H2O), etc., is thermally and chemically stable, does not change in any way against electron impact, and has a very high melting point. Therefore, even if these oxide powders are sealed together with mercury in a discharge tube, they will hardly have any adverse effect on the operating voltage, luminous flux value, lifespan, or other characteristics of the discharge tube.

For example, zirconium oxide (ZrO2) as an oxide powder
, aluminum oxide (A403), titanium oxide (Ti0
2) One or more powders of hafnium oxide (HfO2), yttrium oxide (Y2O2), and magnesium oxide (MgO) powder may be used.

Furthermore, these oxide powders are not toxic and therefore pose no problem in handling.

As a result of various studies on oxide powders, we found that beryllium oxide (Bed), silicic anhydride (SlO2), and lanthanum oxide (La2O3) powders contain a large amount of gas, which may affect the operating voltage, luminous flux, and lifespan of the discharge tube. It could not be used because it would deteriorate.

Furthermore, although sodium oxide (THO2) powder poses no problem in terms of the characteristics of the discharge tube, it is complicated to handle because it is a radioactive substance.

Furthermore, in the above-mentioned oxide powder used in the present invention,
In the case of powder that passes through a sieve with a mesh size of 0.053 mm, adhesion to the mercury surface is easy and sufficient, so the predetermined amount of mercury is reliably encapsulated in the bulb.
．． In the case of powder that did not pass through a 0.053 mm sieve, it was not possible to completely prevent mercury from adhering to the valve exhaust tube because the adhesion to the mercury surface was not sufficient, and once adhering, the powder came off.

A 40W fluorescent discharge tube will be described below as an example of the present invention.

The ZrO2 powder was calcined in air at a temperature of 1400±50°C for 4 hours (the reason for this will be explained later), and then crushed and passed through a sieve with a mesh size of 0.053 mm.
The powder is further dried at a temperature of 50±30°C for 2 hours 1, and the powder is spread as shown in the recess 9 of the powder base plate 3 attached to the cylinder 7 of the exhaust head in Fig. 2, and then the valve exhaust thin tube 1 is placed in the exhaust head cylinder 7. After attaching it to the insertion port 2 and exhausting and removing impurity gas in the 40W valve 4 through the valve exhaust thin tube 1 and exhaust pipe 3, the mercury metering/dropping device 5 is activated to add the dripped mercury to the scheduled amount of sealed mercury. The ZrO2 powder was deposited on the powder base plate 8, and then mercury was sealed into the 40W bulb through the valve exhaust capillary 1.

We made 100 40W fluorescent discharge tubes in this way,
- 100 40W fluorescent discharge tubes are manufactured using the conventional method shown in Figure 1.
As a result of actually measuring the average value and variation of the amount of mercury filled in each tube, the one made in this example had an average value of 19.5 mg, with a standard deviation of 0, compared to the planned amount of mercury filled in one tube of 20 mg.
．． It was 5 mg.

On the other hand, those produced by the conventional method had an average value of 17.0 mg and a standard deviation of 2.0 mg.

As is clear from these results, according to the method of the present invention, the amount of mercury scheduled to be sealed could be reliably sealed into the valve exhaust tube without causing it to adhere to the tube.

In the above example, Z r 02 was heated to 140 ml in air.
The reason for firing at a temperature of 0±50° C. for 4 hours was to inactivate trace amounts of impurities in ZrO2 and remove trace amounts of adsorbed water, mercury ions, etc.

Furthermore, the operating voltage, luminous flux value, and lifespan of the 40W quartz discharge tube made in this example are not only comparable to those of conventional tubes, but also because conventional tubes have large variations in the amount of mercury filled. Although there were large variations in operating voltage, luminous flux value, and lifespan, the tubes made in the examples did not have these variations and had average characteristics.

Other examples include Al2O3, TiO2, HfO2, Y
Even when powders of 2O3 and MgO, mixed powders of ZrO2 and Al2O3, and mixed powders of Al2O3 and TiO2 were used in the same manner as in the above example, the same effect could be obtained without deteriorating the characteristics of the tube. .

Furthermore, it is clear that the present invention can also be used in a case where a predetermined amount of mercury is sealed in a high-pressure mercury vapor discharge tube other than a silicon charge/discharge tube, such as a high-pressure mercury vapor discharge tube, through an exhaust tube.

As explained above, the present invention attaches oxide powder, which does not deteriorate the lamp characteristics even if it is sealed in the discharge tube together with mercury, to the surface of the mercury in the amount scheduled to be sealed, thereby eliminating the wettability of the surface of the mercury and discharging the bulb. Since mercury is sealed inside the tube while preventing mercury from remaining on the inner circumferential wall of the tube, a predetermined amount of mercury can be reliably sealed inside the tube.

In addition, since the oxide powder is attached only to the surface of mercury,
Unnecessary introduction of oxide powder into the bahab can be suppressed to the minimum necessary.

Therefore, it has become possible to prevent deterioration and variations in the characteristics of the discharge tube due to variations in the amount of mercury filled.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view of an exhaust head showing an example of a conventional mercury filling method, and FIG. 2 is a schematic vertical cross-sectional view of an exhaust head showing an embodiment of the mercury filling method of the present invention. Note that the same reference numerals in the figures indicate the same or equivalent parts, 1 is the valve exhaust capillary, 2 is the valve exhaust capillary insertion port 3 is the exhaust pipe,
4 is a 40W valve, 5 is a mercury measuring and dropping device, 6 is a mercury tank, 7 is a cylinder, 8 is a powder base plate, and 9 is a ZrO2 powder.

Claims (1)

[Scope of Claims] 1. In a method of sealing a predetermined amount of mercury through the exhaust tube of a bulb, the predetermined amount of mercury that is dropped onto the surface of the bulb does not deteriorate the lamp characteristics even if it is sealed inside the bulb. 1. A method of filling mercury for a discharge tube, characterized in that after adhering oxide powder, mercury is sealed into a bulb through an exhaust capillary. 2 Zirconium oxide (Zro2) as oxide powder
Aluminum oxide (A12O3), titanium oxide (Ti0
2) A method for encapsulating mercury for a discharge tube according to claim 1, characterized in that one or more of hafnium oxide (HfO2), yttrium oxide (Y2O2), and magnesium oxide (MgO) powder is used. . 3. The method for enclosing mercury for a discharge tube according to claim 1 or 2, characterized in that the oxide powder is sized to pass through a sieve with an opening of 0.053 mm. 4. A method for encapsulating mercury for a discharge tube according to any one of claims 1 to 3, characterized in that the oxide powder is a powder fired at a temperature of 1400±50°C.