JPS59103245A - Manufacturing process for discharge lamp - Google Patents

Abstract

PURPOSE:To enable a glass tube with the strength increased due to its configuration into U-shape to be produced irrespective of its curvature, by heating and softening two glass tubes each of which has its one end closed, thereafter pressurizing the insides of the tubes, forming opening parts in order to connect them to each other, putting them into a molding tool, and molding them into the predetermined shape. CONSTITUTION:The facing parts (parts to be connected) in the vicinity of the closed parts of two glass tubes 1 are locally heated with a gas burner 6, after that, when they are softened, air is fed into respective glass tubes 1 through air- feeding inlets 33. When the parts to be connected to each other project outward and the tips of the projecting parts are perforated by the pressure of air, a holder 22 is moved in order to connect the glass tubes 1 to each other. The vicinity of the connected part 1a is heated with the gas burner 6, the softened part is covered with a molding split die 55, and air is fed thereinto from the air- feeding inlets 33 in order to pressure-mold the inside of the glass tubes. By doing this, the wall-thickness of the curved part of glass can be controlled without difficulty, and consequently, a U-shaped fluorescent lamp having the sufficient strength can be easily produced.

Description

[Detailed description of the invention] The present invention relates to a method of manufacturing a discharge lamp.

Normally, a discharge lamp such as a fluorescent lamp has a structure in which electrodes are arranged at both ends of a straight glass tube, and the discharge between the electrodes excites the gas sealed in the glass tube to emit light.

Generally, the longer the distance between the electrodes, that is, the length of the discharge path, the better the luminous efficiency will be. Therefore, if emphasis is placed on luminous efficiency, a longer shape is more advantageous, but since these discharge lamps are used in various places as a light source,
From the user's point of view.

A small, easy-to-use one is preferable. For this reason9
Various discharge lamps using bent glass tubes as pulp have been proposed with the aim of reducing the size while maintaining a certain level of luminous efficiency.

Figure 1 shows a U-shaped fluorescent lamp, which is a typical example of these discharge lamps. , electrode (2
) is sealed with a stem (3) implanted therein.

Fluorescent lamps with this structure are about half the length of ordinary straight glass tubes that are used as pulp, but have almost the same luminous characteristics.

It is used in fields where miniaturization of light sources is required.

However, compared to lamps using straight glass tubes as pulp, the above-mentioned lamps have a disadvantage in that the manufacturing method, especially the method of manufacturing U-shaped glass tubes, is difficult. Generally, to make a U-shaped glass tube for a lamp like this, the center of a straight glass tube is heated to soften it, and then wrapped around a mold that matches the required U-shaped curvature. It is being said.

However, with this method, if the 1st curvature is small to some extent, it can be bent relatively easily, but the 9th curvature is thick (if this happens, the outside of the 9th bent part will be extremely stretched, resulting in a thinner wall. 9. It has the disadvantage of reduced strength and easy breakage.

The present invention has been made in view of the above points, and it is easy to manufacture and maintains strength regardless of curvature without impairing the functions of conventional discharge lamps that use U-shaped glass tubes as pulp. The object of the present invention is to provide an improved method for manufacturing a discharge lamp.

Two embodiments of the present invention will be described below with reference to FIGS. 2 to 10.

The method of the present invention is characterized by having a step of manufacturing a bent glass tube according to the following procedure.

(1) As shown in Figure 2, hold two straight glass tubes (1) with one end (11) open and the other end (1z) closed with a holder, and open each opening. Air inlet (
2) with a stopper (44).

(2) As shown in FIG. 3, the opposing portions (planned connection locations) near the closed ends of the two glass tubes (1+) held together are locally heated with a gas burner (6).

(3) Once the planned connection points are softened by heating, stop heating and feed air into each glass tube (1) through the air feed schedule. As a result of this operation, as shown in FIG. 4, the planned connection portion protrudes outward, and the air pressure creates a hole (5) at the tip of the protrusion.

(4) While the protrusion remains in a softened state, quickly move the holder (2) and bring the two glass tubes (1) close to each other. By this operation, the periphery of the hole (5) of each protrusion is crimped, and the two glass tubes (
1) are connected.

(5) Next, as shown in Figure 6, two glass tubes (1
The vicinity of the connecting part (1a) of 1 is heated with a gas burner (61) to soften it (6). Cover the softened part with a molding mold 6 with a grooved ring, and pressurize the inside of the glass tube by sending air through the air inlet □□□.This operation removes the softened part of the glass. It swells and fits tightly to the inner surface of the groove (A) of the mold.

(7) After that, turn off the air, return the pressure inside the glass tube (11) to atmospheric pressure, and remove the mold. is completed.

A piezophosphor layer (4) is formed on the inner surface of the U-shaped glass tube (1) manufactured by the above process, and electrode stems (3) are formed on both ends of the U-shaped glass tube (1).
A U-shaped fluorescent lamp is completed by sealing the tube, evacuating the inside, and filling it with a specified amount of mercury and rare gas.

According to the method of the present invention as described above, parts of two straight glass tubes are connected, the connected portion is heated, and then the tube is put into a mold and molded.

Compared to the conventional method of manufacturing by bending a single straight glass tube, it is easier to control the thickness of the glass in one curved section.
Therefore, it is possible to easily manufacture a U-shaped fluorescent lamp with sufficient intensity.

Although the above embodiment describes a U-shaped fluorescent lamp, H-shaped, rectangular, or V-shaped fluorescent lamps as shown in FIGS. 11 to 13 can also be used to produce glass pulp. It can be easily manufactured in a similar manner by appropriately setting the position at which the glass tube is heated, the shape of the mold, and the angle at which the glass tube is gripped.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a U-shaped fluorescent lamp; FIGS. 2 to 9 are views showing one manufacturing method of the present invention in the order of work steps;
FIG. 10 is a perspective view of the same molding die. 11 to 13 are partial cross-sectional views of fluorescent lamps according to other embodiments of the present invention, in which FIG. 11 shows a fluorescent lamp in which the connection molding part is approximately H-shaped, and FIG. 12 shows a fluorescent lamp in which the connecting molding part is also approximately rectangular. The fluorescent lamp shown in FIG. 13 is a fluorescent lamp that is also approximately square-shaped. In the figure, (1) is a glass tube, (1a) is a connecting part,
(G) is a mold for molding. In each figure, the same reference numerals indicate the same or corresponding parts. Agent Makoto Kuzuno - Figure 1 Figure 2 Figure 4 Figure 3 Figure 5 Figure 17 Figure 12

Claims (1)

[Claims] After softening the two glass tubes with one end open and the other end closed by heating, the interior of the glass tubes is pressurized, and this pressurizing force allows the two glass tubes to be connected externally. While protruding in the opposite direction, the tip of the protrusion is blown open to form an opening.Then, the opening of each glass tube is heated and softened, and the glass tubes are connected in a state in which they communicate with each other. Subsequently, the connecting portion is heated and softened, and then the connecting portion is placed in a mold, and in this state, the inside of the glass tube is pressurized to form the connecting portion into a predetermined shape. .