JPS60107239A - Bulb exhausting apparatus - Google Patents

Abstract

PURPOSE:To efficiently exhaust the gas containing impurity which is emitted within a bulb by high frequency discharge by providings drift generating apparatus which applies electric field and magnetic field crossing each other to an exhaust bulb to the outside of said exhaust bulb. CONSTITUTION:The electromagnets 17a, 17b of a drift generating apparatus generate a magnetic field B within an exhaust bulb 2 in such a direction as orthogonally crossing the axis of exhaust bulb 2, while the electrode plates 18a, 18b generate an electric field E which orthogonally crosses the axis and magnetic field B. A valve 4 is opened and a valve 1 is vacuumed by a vacuum pump 5. Next, a valve 6 is opened in order to supply inactive gas within a gas bomb 7 to the valve 1 through the exhaust bulb 2. When a high frequency signal is applied to the valve 1 with a high frequency coil 14, discharges are generated within the valve 1 and thereby impurity absorbed by the valve 1 is emitted. Next, a valve 8 is opened and the gas in the valve 1 is attracted toward a vacuum tank 9. In this case, when the electric field E is generated simultaneously with magnetic field B, gas particles are given acceleration based on the drift movement and thereby it passes at a high speed throughout the exhaust bulb 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an apparatus for evacuating the inside of a valve during a tube manufacturing process.

[Technical background of the invention and its problems]

In bulbs made of quartz, glass, or ceramic bulbs sealed with tungsten H electrodes or filaments, there may be dirt on the inner walls of the bulb or electrodes, adhesion of impurities such as moisture, or residual gas or oxidized layers. Since the quality of the tube will deteriorate significantly if the tube is exposed to heat, degassing is performed during the tube manufacturing process.

Conventional degassing treatment involves heating the bulb with the reeds, electrodes, and filament sealed together using an electric furnace and heating it from the outside.At this time, the electrodes and filament are energized, and the inside of the bulb is pumped through the exhaust pipe with an exhaust pump. It was meant to be vacuumed. However, with this type of degassing treatment, since the valve is heated, it takes time for the valve to reach a predetermined temperature, and it also takes time to cool the valve to room temperature after degassing, which reduces work efficiency. There is a drawback that the price is low.

Instead of such heating degassing treatment, plasma exhaust treatment has been proposed.
After exhausting the air once, supply nitrogen gas or argon gas to this valve, and apply high frequency from outside the pulp using a high frequency coil etc. to generate a discharge within the pulp and generate plasma in the inert gas. It is something that makes you

This high-frequency discharge knocks out impurities attached to and occluded on the bulb walls, electrodes, etc., and removes them, thereby eliminating the gas inside the bulb.

This plasma exhaust method does not require heating the valve or energizing the electrodes, so it does not require a heating furnace or power supply device, and there is no need to wait for the pulp temperature to rise or fall. This has the advantage of improving work efficiency.

However, since the impurities knocked out into the pulp by the high frequency discharge are removed through the exhaust pipe, the problem remains that the removal efficiency is not good. In other words, the impurities knocked out by the high-frequency discharge are removed by the exhaust pump, and the removal time is determined by the inner diameter of the exhaust pipe and the gas flow rate flowing therethrough. Since the size of the exhaust pipe cannot be increased without limit, the exhaust time must be shortened by increasing the gas flow rate. Ultimately, the degree of vacuum inside the pulp is required to be as high as 1o-Llo-'Torr, and if you try to achieve this in a short time, you have no choice but to use a vacuum pump with a large exhaust capacity, which makes the equipment expensive. There was a problem.

[Purpose of the invention]

The present invention was made based on the above circumstances, and its purpose is to provide a tube exhaust device that can efficiently eliminate gas containing impurities ejected by high-frequency discharge. That is.

[Summary of the invention]

The present invention is characterized in that a drift generator is provided outside the exhaust pipe to apply mutually orthogonal electric and magnetic fields to the exhaust pipe, and plasma charges are generated by discharge within the pulp. The applied gas particles are accelerated by drift motion due to the action of the electric field and magnetic field, and are forcibly removed.

[Embodiments of the invention]

An embodiment of the present invention will be described below based on the drawings.

In the figure, 1 is an outer bulb of a discharge lamp, and a discharge tube (not shown) is mounted inside. Reference numeral 2 indicates an exhaust pipe led out from the valve l. The exhaust pipe 2 is connected to a branch connecting pipe 3. The branch connection pipe 3 is connected to a vacuum pump 5 via a first electromagnetic on-off valve 4, and
It is connected to a nitrogen gas or argon gas pump 7 via a second electromagnetic on-off valve 6, and further connected to a vacuum tank 9 via a third electromagnetic on-off valve 8. The vacuum tank 9 is connected to an exhaust pump 11 via an on-off valve 10, and a predetermined high vacuum is maintained by the exhaust pump 11. The first to third electromagnetic on-off valves 4.6.8 are opened and closed by instruction signals from the controller 12. The controller 12 is a computer (CPU) 1
Controlled by 3.

The pulp 1 is surrounded by a high frequency coil 14, and is caused to undergo plasma discharge by this high frequency coil 14. The high frequency coil 14 is connected to a high frequency power source 15, and this high frequency power source 15 is connected to the high frequency coil 1 by the computer 13.
On, off and frequency controls for 4 are adjusted.

A drift generator 16 is provided around the exhaust pipe 2. As shown in FIG. 2, the drift generator 16 includes a pair of electromagnets 17 a e 17 b sandwiching the exhaust pipe 2, and an electrode plate 18a perpendicular to these electromagnets 17a and 17b.
, 18b are arranged. A pair of electromagnets 17
h, 17b generates a magnetic field B in the exhaust pipe 2 in a direction perpendicular to the axis of the exhaust pipe 2, and a pair of electrode plates 18m
, 18b generate an electric field E that is perpendicular to the axis and perpendicular to the magnetic field B.

The electromagnets 17h and 17b are connected to an electromagnet power source 19, and the electrode plates 18m and 18b are connected to an electrode plate power source 2o. The on/off of these power supplies 19 and 20 and the strength of the magnetic field B and electric field E are controlled by the computer 13.

A procedure for degassing using such an apparatus will be explained.

After connecting the exhaust pipe 2 of the valve 1 to the branch connection pipe 3, the vacuum pump 5 is activated and the first electromagnetic on-off valve 4 is opened. For this reason, the air inside the valve 1 is drawn out to an angle of 7°5. This evacuation is performed until the inside of the valve l reaches several Torr.

Next, close the first electromagnetic on-off valve 4, and close the second electromagnetic on-off valve 6.
open. Then, nitrogen gas or argon gas in the gas chamber 7 is supplied into the valve l through the exhaust pipe 2. When the gas pressure within the valve l reaches approximately 200 to 600 Torr, the second electromagnetic on-off valve 6 is closed.

The high frequency power source 15 is activated and the high frequency coil 14 applies high frequency to the valve l. This causes a discharge within the valve 1. This high-frequency discharge knocks out impurities attached to or occluded on the bulb 1 and the mounting member inside the bulb 1, and also generates plasma in the gas.

Next, the third electromagnetic on-off valve 8 is opened to suck the gas inside the valve 1 into the vacuum tank 9 side. At this time, electromagnets 17a, 1
While generating a magnetic field B between electrode plates 18a and 1
An electric field E is generated between 8b. Due to the action of the magnetic field B and the electric field E, acceleration based on drift motion is applied to the gas particles charged by the high-frequency discharge, so that the gas passes through the exhaust pipe 2 at high speed.

The drift motion will be explained with reference to FIG. Generally, when a magnetic field B is present, electrons and ions undergo cyclotron motion in which they are wrapped around magnetic lines of force. Electrons and ions have different rotation directions, rotation diameters, and angular frequencies, but
Centrifugal force and electromagnetic force acting on particles on a circular orbit maintain mechanical equilibrium. However, when an electric field E perpendicular to the magnetic field vector B is further applied to the charged particles in the magnetic field B, the particles do not move in the E direction, and due to a mechanism called ``l'-E'xn drift,'' E and B are causes a "drift motion" in a direction perpendicular to .

This drift motion is constant regardless of the sign of the charge or the size of the mass.

Therefore, when a uniform external magnetic field is applied to the plasma, when the electrostatic field E perpendicular to the magnetic field B overlaps, the particles cross the magnetic lines of force and move in the direction perpendicular to both B and E. Subjected to acceleration in the direction of the tube axis.

Therefore, if the drift generator 16 of this embodiment is used, the gas inside the valve 1 can be removed extremely quickly.
A high degree of vacuum can be obtained with a short evacuation time, and the exhaust pump 11
There is no need to use a pump with a particularly large exhaust capacity.

Valve 1 by using such a drift generator 16
When the pressure inside the pump 1 reaches several Torr due to the exhaust gas inside, the third electromagnetic on-off valve 8 is closed and the power supply 19, 20 is turned off. Then, open the second electromagnetic on-off valve 6 again and open the valve 1.
Nitrogen gas or argon gas is introduced into the chamber, high-frequency discharge is caused, and exhaust is repeated by the drift generator 16. This is repeated about 30 times, and the time required for one cycle is about 5 seconds. .

As a result, the inside of the valve 1 can be made into a high vacuum and degassed with high purity.

Note that when electric discharge is generated within the outer bulb 1, light emission is accompanied by plasma. This light emission also differs depending on the state of use. Therefore, the progress of degassing can be confirmed by observing the state of plasma light emission.

The present invention is applicable not only to outer bulbs of discharge lamps, but also to arc tubes of discharge lamps, bulbs of fluorescent lamps, bulbs of incandescent lamps, and the like.

〔Effect of the invention〕

According to the present invention as described above, the gas after plasma generation can be removed at high speed by the drift generator installed in the exhaust pipe, so the gas removal time can be significantly reduced without using a large-capacity exhaust pump. Therefore, gas removal work can be performed with high efficiency. Therefore, in combination with knocking out impurities by high-frequency discharge, the degassing process of the tube can be carried out efficiently, making mass production possible.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is an explanatory diagram showing the configuration of an exhaust device, FIG. 2 is an explanatory diagram of a drift generator,
FIG. 3 is a diagram explaining the principle of drift motion. 1... Valve, 2... Exhaust pipe, 5... Vacuum pump, 7... Gas cylinder, 9... Vacuum tank, 14...
- High frequency coil, 16... drift generator. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2-m-] Figure 2 0 Figure 3

Claims (1)

[Claims] A vacuum system connected to the exhaust pipe of the valve and evacuating the inside of the valve, a gas source connected to the exhaust pipe and supplying inert gas into the evacuated valve, and a high-frequency power supply provided around the valve. a high frequency generator that generates plasma in the inert gas by causing discharge in the bulb by applied high frequency; a means for expelling the inert gas in the bulb through an exhaust pipe after the plasma is generated; A tube exhaust device comprising a drift generator that applies an electric field and a magnetic field orthogonal to each other to the exhaust pipe during gas exhaust.