JPH0471293B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a low-pressure mercury vapor discharge lamp in which mercury vapor pressure is controlled by an amalgam.

[Technical background of the invention and its problems]

In low-pressure mercury vapor discharge lamps, typically fluorescent lamps, the efficiency of converting supplied electricity into ultraviolet light is highest when the tube wall temperature is around 40°C and the mercury vapor pressure is approximately 6 × 10 ^-3 mmHg. For example, if this fluorescent lamp is housed in a bulb-shaped envelope and turned on, the mercury vapor pressure will exceed the above value as the ambient temperature rises, and the light output will decrease. Problems such as deterioration occur.

When a fluorescent lamp is used under such severe temperature conditions, the mercury vapor pressure inside the fluorescent lamp is controlled within an appropriate range by using amalgam, which has a lower vapor pressure than pure mercury. The method is considered effective.

By the way, conventionally, this type of amalgam is often installed on the stem wall surface at the end of the lamp via a wire mesh-like base, but this amalgam is placed in a coexistence state of solid and liquid depending on the temperature, and the above-mentioned Because the location is close to the electrodes, there was a problem that depending on the composition of the amalgam, it would melt and flow out during lighting.

Therefore, as a countermeasure to this problem, the present inventors have proposed installing amalgam in the form of granular masses within the thin tube of the stem extending on the opposite side from the electrodes, and have already filed an application for this proposal.

In this case, the amalgam is introduced through the opening at the tip of the capillary before the capillary is sealed, but in order to prevent the amalgam from falling into the bulb of the fluorescent lamp, a passage is pre-shaped in the middle of the capillary. A constriction section is provided.

However, in normal fluorescent lamp manufacturing technology, this narrow tube is used to exhaust the inside of the bulb, so if the narrow tube is narrowed in the middle as described above, the conductance of the exhaust air will become small. , problems such as the time required for evacuation occur.
Therefore, in consideration of this exhaustion, when providing a constriction part in a thin tube, it is necessary to take measures to ensure that it does not obstruct exhaustion.
The inventors of the present invention have devised the shape and size of the diaphragm to make the evacuation time almost the same as that of a general fluorescent lamp, making it practical.

However, in any case, the narrow tube that serves as the exhaust passage is still constricted in the middle, so if you try to shorten the exhaust time, this constricted part becomes an obstacle, and new improvements cannot be made. Measures are becoming necessary.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and provides a method for manufacturing a low-pressure mercury vapor discharge lamp that can shorten the evacuation time despite the presence of a constriction part in the thin tube to prevent the amalgam from falling. The purpose is to

[Summary of the invention]

That is, in order to achieve the above object, the method of the present invention forms a constricted portion by heating and pressing the middle of the thin tube connected to the exhaust device during or after the evacuation of the arc tube, and then Once the amalgam is introduced through the tip opening, the tip opening of the thin tube is hermetically sealed by melting.

[Embodiments of the invention]

The present invention will be explained below based on an embodiment shown in the drawings.

This example shows a case in which the low-pressure mercury vapor discharge lamp according to the present invention is housed together with a lighting device in a ball bulb-shaped envelope and is applied to a lighting device used in place of an existing incandescent light bulb. In the figure, reference numeral 1 denotes a cover made of synthetic resin, and a cap 2 is attached to the top of one end of the cover 1. A substantially spherical globe 3 is fitted into the opening at the other end of the cover 1.
The cover 1 and the globe 3 constitute an envelope 4 that approximates a ball-shaped incandescent light bulb.

Inside the envelope 4, a fluorescent lamp 5, which is a typical low-pressure mercury vapor discharge lamp, a lighting tube 6 as a starting element of the fluorescent lamp 5, and a chiyoke coil type ballast 7 as a discharge stabilizing element are integrated. is accommodated. The luminous tube 8 of the fluorescent lamp 5 is made by bending a straight glass bulb into a substantially U-shape at the center between the two ends 9, 9, and the curved part 10 and the two ends 9, 9. The space between the two ends is curved into a substantially U-shape in a direction substantially orthogonal to the plane containing the U-shape, and both end portions 9, 9 and the curved portion 10 are located adjacent to each other in the same direction. Flare portions 12 of a mount 11 are sealed to both ends 9, 9 of the arc tube 8, and a discharge space 13 is formed within the arc tube 8 by this sealing. Internal lead wires 15, 15 are sealed in the stem tube 14 connected to the flared portion 12, and a filament 16 as an electrode is connected between these internal lead wires 15, 15. Further, from the stem tube 14, a filament 16
A cylindrical thin tube 17 is led out toward the opposite side. The base end of this thin tube 17 is inserted into the discharge space 1 through an opening 18 provided at the tip of the stem tube 14.
This thin tube 17 is used to exhaust the interior of the arc tube 8 and to fill it with inert gas. Such a fluorescent lamp 5 has both ends 9, 9.
The filament 16 is housed in the envelope 4 with the bending portion 10 facing the mouthpiece 2 side.
However, not only the lighting tube 6 but also the cap 2 is connected via the ballast 7.
is connected to.

Note that reference numeral 19 in FIG. 1 is a phosphor coating coated on the inner surface of the arc tube 8.

By the way, the thin tube 17 of the one mount 11 mentioned above
An amalgam 20 is sealed inside the tube to control the mercury vapor pressure inside the tube during steady lighting. The amalgam 20 of this example is made by adding a predetermined amount of mercury (Hg) to an alloy made by mixing indium (In), bismuth (Bi), tin (Sn), lead (Pb), and these various metals in appropriate proportions. It is formed into one approximately spherical lump. In order to prevent the amalgam 20 from falling into the arc tube 8, a constriction part 21 is formed in the middle of the capillary tube 17, in which the opening area of the passage 24 in the capillary tube 17 is narrowed. is held between the constricted portion 21 and the sealing portion 17a at the tip of the thin tube 17.

Next, a method for manufacturing such a fluorescent lamp 20 will be explained.

That is, as shown in FIG. 5, the mount 11 is sealed to the arc tube 8 and the phosphor coating 1 is sealed.
When the deposition of the arc tube 9 is completed, the arc tube 8 is supplied to each head 25a on the rotatably driven spider 25. The arc tube 8 is held at one end 9 by the valve chucks 26, 26, and is sent to each position on the spider 25 with the tip opening of the thin tube 17 facing upward. Luminous tube 8
When the gas is sent to the exhaust position, the valve chucks 26, 26 are raised as shown in FIG. Exhaust is performed. At this time, the entire arc tube 8 is heated by a heating furnace (not shown), and the filament 1
6 is energized, and the arc tube 8 as well as
The removal of impurities contained in the mount 11 and filament 16 is facilitated.

Then, when the arc tube 8 is sent to the aperture position set just before the end of this exhaust process, a constriction part 21 is formed in the middle of the thin tube 17 by the heating and pressing mechanism 28 provided in the head 25a. Here, this heating and pressing mechanism 28 will be explained with reference to FIGS. 6 and 7. The head 25a has a thin tube 17.
A pair of pressing jigs 29, 29 that are located on both sides in the radial direction and are movable in directions toward and away from each other are attached. A receiving recess 30b into which the thin tube 17 enters is provided on the other side.
is formed. Then, each pressing jig 29, 2
Guide pins 31, 31 are protruded from the upper surface of the slider 32.
It is slidably engaged in elongated guide holes 33, 33 opened in the. This slider 32 is connected to a piston rod 35 of an air cylinder 34, and is reciprocated in a direction toward and away from the arc tube 8, that is, in a direction perpendicular to the moving direction of the pressing jigs 29, 29. When the slider 32 is pushed out toward the arc tube 8 against the biasing force of the return springs 36, 36, the guide pins 31, 31 are guided by the guide holes 33, 33 and drawn inward, and are pressed. The jigs 29, 29 abut against each other, and the thin tube 17 is held between the abutting surfaces.

Further, a pair of burners 37, 37 are installed above the pressing jigs 29, 29, and below the pressing jigs 29, 29, the sealed end of the arc tube 8 is connected to the burners 37, 37. A heat shield plate 38 is arranged to prevent exposure to the flame ejected from 37. Therefore, when the arc tube 8 is sent to the aperture position, the middle part of the thin tube 17 is first heated and softened by the burners 37, 37, and then the air cylinder 3
4 is activated, and the heated softened portion of the thin tube 17 is clamped by the pressing jigs 29, 29. At this time, thin tube 1
The clamping portion 7 is crushed from one side in the radial direction by the pressing protrusion 30a, and at this point, the inside of the arc tube 8 is being continuously exhausted through the thin tube 17, so the inside of the thin tube 17 is under negative pressure. Therefore, as shown in FIG. 3, the constricted portion 21 assumes a bulging shape as it enters the thin tube 17.

If the aperture part 21 is formed in this way,
The constricted portion 21 is once cooled, and then the spherical amalgam 2 is introduced into the thin tube 17 through the exhaust device 26.
Insert 0. Subsequently, an inert gas such as argon is filled into the arc tube 8 through the exhaust device 26 and the capillary 17, and finally the tip opening of the capillary tube 17 is sealed with a sealing burner (not shown) built into the exhaust device 26. The series of steps is completed by airtightly fusing and sealing.

According to such a manufacturing method, the narrow tube 17 is subjected to the drawing process immediately before the end of the exhaust process in the arc tube 8, so that the narrow tube 17 does not have the narrow part 21 during most of the exhaust process. First, this makes the exhaust conductor tank sufficiently large, making it possible to shorten the exhaust time.

In addition, in the case of this embodiment, after the thin tube 17 is inserted into the exhaust head 27, the thin tube 17 is drawn. Mutual positional displacement can be prevented.
That is, in the past, the thin tube 17 that had been drawn in advance was inserted into the exhaust head 27, so if the thin tube 17 was bent as shown by the imaginary line in FIG. Occasionally, this thin tube 17 may break, but if the process is carried out as in this embodiment, breakage of the thin tube 17 can be prevented. Therefore, there is no decrease in yield during the series of steps, and the above-mentioned evacuation time is shortened. Combined with this, it contributes to improving manufacturing efficiency.

In addition, in the above-mentioned embodiment, the thin tube was subjected to the drawing process immediately before the end of the exhaust process, but the present invention is not limited to this, and the thin tube may be subjected to the drawing process after the exhaust process is completed. .

Furthermore, the low-pressure mercury vapor discharge lamp according to the present invention is not limited to one that is housed in a bulb-shaped envelope and used for lighting, but can also be used externally, such as a high-output straight tube type or curved tube type fluorescent lamp. It can be similarly applied as a light source for a copying machine that is illuminated by exposing it to one side, or a light source for a copier that blinks many times.

Furthermore, the amalgam may also be housed not only in the tubules of one mount, but also in the tubules of both mounts.

〔Effect of the invention〕

According to the method of the present invention described in detail above, the constriction part for preventing amalgam from falling off does not obstruct the evacuation, and therefore the evacuation conductance becomes sufficiently large, making it possible to shorten the evacuation time and manufacture the product. It has the advantage of increasing efficiency.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a sectional view of the end of the arc tube, Fig. 2 is a partially sectional perspective view of the entire discharge lamp, and Fig. 3 is a sectional view showing an enlarged diaphragm portion. Figure 4 is a sectional view of the illumination device, Figure 5 is a side view of the manufacturing equipment, Figure 6 is a front view of the heating and pressing mechanism, Figure 7 is a plan view thereof, and Figure 8 is during the exhaust process. FIG. 3 is a side view showing the relationship between the arc tube and the exhaust device. 8... Arc tube, 11... Mount, 13... Discharge space, 16... Electrode (filament), 17...
...Thin tube, 17a... Sealing part, 20... Amalgam, 21... Squeezed part, 24... Passage.

Claims (1)

[Scope of Claims] 1. An arc tube that forms a discharge space inside, and thin tubes that are sealed to both ends of the arc tube and communicate with the electrode and the discharge space to exhaust the discharge space. and a mount having a mount, and housing an amalgam for controlling mercury vapor pressure in the arc tube in the capillary of at least one of the mounts,
A low-pressure mercury vapor discharge lamp is provided in which a constriction part is provided in the middle of the capillary tube to prevent the amalgam from falling into the discharge space, and the amalgam is held between the constriction part and the sealing part at the tip of the capillary tube. In the manufacturing method, the constricted portion is formed by heating and pressing the middle of the arc tube during or after exhausting the interior of the arc tube through the capillary, and then amalgam is introduced into the capillary through the tip opening. A method for producing a low-pressure mercury vapor discharge lamp, which comprises airtightly sealing the opening at the tip of the capillary once it has been introduced.