JPS6110830A - Manufacture of low-pressure discharge lamp - Google Patents

Abstract

PURPOSE:To perform the formation of an end stem in an accurate manner in a simple method, by setting a lead bar and a glass material to a press forming device, while applying pressure to the glass material with heating. CONSTITUTION:Each of lead bars 61A and 61B is held between pressing parts, namely, between an upper pressing part 77 and a lower pressing part 71 of a press forming device 7, while a glass material 8 is set up therein, and both these pressing parts 77 and 71 are made to move forward so as to make them come closer with each other along a direction toward these lead bars 61A and 61B. Therefore, a glass plate part 62 moded in plate form and an end stem 6 having a lead bar to be extended as airthightly piercing this plate part 62 both are formed up. With this constitution, formation of the end stem is performable so accurately in a very simple method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a low-pressure discharge lamp such as a mercury lamp, particularly a low-pressure discharge lamp that is operated at a discharge current of IA or less.

[Prior art]

Discharge lamps, such as mercury lamps, generally emit ultraviolet i? It is widely used in fields such as the former chemical industry, semiconductor manufacturing, and other fields.

In an example of a conventional mercury lamp, as shown in FIG. 2, an end stem 2 airtightly connected to an end 11 of a quartz glass tube 1 includes glue rods 21A and 21B made of tungsten, for example.
A column-shaped arrival glass part 22 is airtightly welded so that the central parts of the leads #21A and 21B are buried and fixed, and a circular tubular glass part 22 is successively hermetically welded and stepped to this sealing glass part 22. The first glass part 23, the second glass part 24 in the shape of a cylinder, the third glass part 25 in the shape of a cylinder, and the fourth glass part 26 in which the outer end of the cylinder is expanded into a brim shape are machined. The end stem 2 is connected to the quartz glass tube 1 by welding the outer edge of the brim-shaped end of the fourth glass portion 26 to the end 11 of the all-silica glass tube 1. Internal leads 3A and 3B are welded to one end of the lead rods 21A and 21B, respectively, and a filament 4 for electron emission is fixed between the tips of the internal leads 3A and 3B. 5
A and 5B are external leads welded to the other ends of the lead rods 21A and 21B, respectively.

The arrival glass portion 22 includes a lead rod 21 A z 21
The first glass part 23, the second glass part 24, the third glass part 25, and the fourth glass part 26 are made of a glass material whose coefficient of thermal expansion almost matches the coefficient of thermal expansion of B. Each material is selected in order to have a coefficient of thermal expansion close to that of quartz glass.

Like this, there is 8 on the end stem 2 and the glass part? The purpose of connecting multiple stages is to avoid sudden changes in the coefficient of thermal expansion between the interconnected materials. By making the change in the coefficient of thermal expansion gradual in this way, it is possible to This prevents the occurrence of cranks caused by thermal stress.

However, in manufacturing the end stem 2 having such a configuration, the first glass part 23 to the fourth glass part 26
1, which requires several joints 8, and it is difficult to perform such step joints mechanically, so they are usually done manually. Therefore, it is quite ripe for the connection process! In addition, when using an end stem with a step-jointed structure, there is a problem that it requires a considerable amount of time and effort to manufacture the discharge lamp, and the manufacturing cost is high. Since the length of the part protruding from the end face of the quartz glass tube 1 into the quartz glass tube 1 inevitably becomes large, there is a problem that there is a limit to miniaturization by reducing the length of the entire discharge lamp. .

Especially for low-pressure discharge lamps that are lit with a discharge current of 1AJJ or less? However, when the end stem is manufactured by the method described above, the above-mentioned problems become extremely large, and the manufacturing cost becomes extremely high. Moreover, it is difficult to sufficiently reduce the size of the device despite its low power consumption.

[Purpose of the invention]

The present invention (a) has been made based on the above-mentioned considerations, and its purpose is to simplify manufacturing, reduce manufacturing costs, and downsize. The object of the present invention is to provide a new method for fabricating a low-pressure discharge lamp that can be achieved.

[Structure of the invention]

The above purpose is to provide a method for manufacturing a low-pressure discharge lamp that is lit with a discharge current of IA or higher. glass material placed in? By applying pressure with the press molding tool while heating, a glass plate portion that has been completely formed into a plate shape and an end stem having a lead rod that extends through the glass plate portion in an airtight manner are completely formed. The process of airtightly welding the two glass plates on the stem to the end of the quartz glass tube and connecting them to the end stem purple quartz glass tube. A method for manufacturing a low-pressure discharge lamp, wherein the glass plate portion of the end stem has a coefficient of thermal expansion that is intermediate between a coefficient of thermal expansion of quartz glass and a coefficient of thermal expansion of the lead rod. achieved by.

The non-inventive method will be explained in detail below with reference to the drawings.

In one embodiment of the present invention, as shown in FIG. It is held vertically in the holding holes 72A, 72H provided in the lower pressing part 71, and is held in such a state that the upper part thereof is almost exposed from the medium heat.

The thermal expansion coefficient of quartz glass (approximately 5
10'~6X10-7) and the lead rods 61A, 6
1B (about 40.times.10.sup.-7) and a glass material 8 having a thermal expansion coefficient intermediate to that of 1B (about 40.times.10@-7), for example, GE Glass 7, Flat 1 (thermal expansion coefficient: about 13.times.10@-7).

Then, the glass material 8 is melted by high-frequency heating using a high-frequency heating coil 75 wound around the outer periphery of the outer casing 74 of the press molding tool 7, and an inert gas is introduced into the outer casing from the gas introduction 076 below the outer casing 74. 74, the lead rods 61A and 61B are inserted into the receiving holes 78A and 78B of the upper suppressing portion 77, respectively. (support) part is moved downward so as to approach the lower pressing part 71, and between the upper pressing part 77 and the lower pressing part 71, 8 parts of the glass material in the molten state are pressed. After that, by cooling, as shown in FIG. 3, a glass plate portion 62 formed into a circular plate shape and lead rods 61A and 61B that extend through the glass plate portion 62 in an airtight manner are formed! 6 end stems are formed.

In forming the end stem 6, expanded portions 79 with slightly larger hole diameters 7L are provided at the lower ends of the receiving holes 78A, 78B of the upper pressing part 77 and at the upper ends of the holding holes 72A, 72B of the lower pressing part 71. 8), as shown in FIG. 3, the part of the glass plate part 62 that connects the two lead rods 61A and 61B has a slightly bulged shape, and the glass plate part 62 and the lead rods have a slightly bulged shape. The contact area with 61A and 61B increases and the welding strength increases.

The end stem 6 has 8'CH1 internal leads 53A, 63B'ft made of nickel, for example, each with a lead rod 61.
A, connect to one end side of 61B, and connect lead rod 61A
, 61B are connected to external leads 64A, 64Bk made of nickel, respectively. Internal +'63A
, 6313 are connected with a filament 65 (j).

The end stem 6 thus obtained? , as shown in FIG. 4, the filament 65 is positioned within the quartz glass tube 9 and is hermetically connected to the ten thousand ends 91A of the quartz glass tube 9. That is, the edge 621 of the glass plate portion 62 of the end stem 6 is hermetically welded to, for example, the opening edge 911A of the end 91A of the quartz glass tube 9 while heating. At the other end 91B of the quartz glass tube 9? The end stem 6' manufactured in the same manner as described above? The end stem 6' is connected to the end 91B in the same manner as described above, and the enclosure 10 is heated at 10°C.
Form.

For example, mercury, inert gas, etc. cost 1 k for 10 yen for N bottles. The amount of these enclosed is when lit (temperature approximately 40-60℃)
To? The pressure within the enclosure 10 is approximately 2° Torr or less.

[Function and effect of the invention]

As can be understood from the above description of the embodiments, the method of the present invention provides the following effects.

(1) A lead rod is held between the pressing parts of the punch forming tool, that is, between the upper pressing part and the lower pressing part, and a glass material is used. The device uses the white glass material while heating the upper pressing part and the lower pressing part? Moving the lead rods toward each other along the direction IC and applying pressure, 1. In order to form a glass plate portion formed into a plate shape, a reed rod that extends through the glass plate portion in an airtight manner, and a rounded end stem, in other words, the reed rod and the glass material. Although it is an extremely simple method of placing the glass material in a press molding tool and applying pressure while heating the glass material Rk, the end stem can be formed reliably.

Moreover, since the work can be carried out automatically using a mechanical means called a Punsu forming tool, no particularly skilled skills are required from the operator, and in addition, the standardized end stem with high dimensional accuracy Can this box be formed to reduce production costs and speed up the production line? can be easily achieved.

(2) And, ■ As the material of the glass plate in the end stem, use a glass material whose coefficient of thermal expansion is intermediate between that of the quartz glass tube and the rod, and ■ The radiation flow is IA. Since it is a low-pressure discharge lamp that is lit with the following, the outer diameter of the lead rod? Can it be made very small and yet when lit? In this case, the temperature rise of the lead rod, glass plate, and quartz glass tube is small, so when turning on the low-pressure discharge lamp,
In this case, the thermal stress generated between the lead rod and the glass plate part and between the glass plate part and the quartz glass tube is extremely small. Although there is a large step in the coefficient of thermal expansion at the shank leading to the tube, it does not cause cracks and ultimately does not reduce its temperature durability. be able to.

(3) (-, the end stem has a shape in which the lead rod passes through the half-phase glass plate part airtightly, and the glass plate part 7
Since the connection is made to close the opening at the end of the quartz glass tube, the length of the end stem protruding into the quartz glass tube is the length from the glass plate to the filament, which is the same as in the case of a conventional stepped joint structure. As a result, the length of the discharge lamp is significantly shorter than that of the conventional step-jointed structure. As a result, it becomes possible to achieve a complete miniaturization of the discharge lamp.

To this invention? However, the present invention is not limited to the above embodiments, and various modifications can be made. That is, (a) The specific shape of the press molding tool may be determined as appropriate based on the size of the end stem to be manufactured.

(b) As the heating means in the press molding tool, other means than high-frequency heating may be used.

(c) The coefficient of thermal expansion of the glass plate of the end stem should be an intermediate value between the coefficient of thermal expansion of the quartz glass tube and the coefficient of thermal expansion of the lead rod. :IiI redundancy should be selected.

(d) The present invention can also be applied to the production of fireworks lamps; in this case, a firefly film may be formed on the inner surface of the quartz glass tube.

As explained in detail above, according to the present invention, manufacturing is simple and manufacturing costs can be completely reduced.
Furthermore, it is possible to provide a novel method for manufacturing a low-pressure discharge lamp that can achieve downsizing.

[Brief explanation of the drawing]

Is Fig. 1 the main part of the laughing embodiment of the present invention? An explanatory drawing for explanation, Fig. 2 is an example of a mercury phantom end stem formed by a conventional method? The explanatory diagram shown in FIG. 3 is an example of an end stem formed using method 2 of the present invention. FIG. 4 is an explanatory diagram schematically showing an example of a low-pressure discharge lamp manufactured using the method of the present invention using sound. 1. Quartz glass tube 11. End portion 2. End stem 21A, 21B... Lead rod 22...
- Arrival glass part 23.24.25.26...Glass part 3A, 3B...Internal lead 4...Filament 5
A, 5B... External lead 61A, 61B... Lead rod 7... Press forming tool 71... Lower pressing part 72A, 72B... Holding hole 9... Quartz glass tube 73... Ukeya Part 8...Glass material 74.
... Outer box 75 ... High frequency heating coil 7
6...Gas inlet 77...Upper pressing part 78
A, 78B...Reception hole 62...Glass plate portion 6...End stem 63A, 63B...Inner lead 64A, 64B...Outer lead 65...Filament 91A...End 621 ...
Edge 911A...Opening edge 91B...End 6
'... End stem lO... Enclosure Figure 1 Figure 3

Claims (1)

[Claims] 1) A method for manufacturing a low-pressure discharge lamp that is lit with a discharge current of 1A or less, which comprises holding a lead rod and pressing press molding tools that approach each other along the direction of the lead rod. An end stem having a glass plate portion formed into a plate shape by applying pressure with the press molding tool while heating a glass material disposed between the portions, and a lead rod extending through the glass plate portion in an airtight manner. and connecting the end stem to the quartz glass tube by airtightly welding the glass plate portion of the end stem to the end of the quartz glass tube, the glass plate portion of the end stem being A method for manufacturing a low-pressure discharge lamp, characterized in that the coefficient of thermal expansion is an intermediate value between the coefficient of thermal expansion of quartz glass and the coefficient of thermal expansion of the lead rod.