JPS6362862B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves sealing a metal or ceramic stem to the open end of a glass bulb using an inorganic adhesive (hereinafter referred to as frit) such as low-melting glass. , relates to a discharge lamp whose interior is an airtight space.

A representative example of this type of discharge lamp is a single-end fluorescent lamp, as shown in FIG. 1, which is provided with an inner tube for regulating a discharge path. That is, in the figure, 1 is a glass outer bulb whose one end 11 is open, and 3 is a stem fixed to the end 11 of the outer bulb 1 with a frit 4 so as to close the opening at the end. ,
Reference numeral 5 indicates two electrodes sealed to the stem 3, and reference numeral 6 indicates the stem 3, one end of which includes one of the electrodes 5.
Two U-shaped glass inner cylinders are fixed in an airtight manner to the inner cylinder 6 with the other end open, 2 is a phosphor layer coated on the inner surface of the inner cylinder 6, and the inner cylinder 6 is an electrode 5.
While regulating the discharge generated between them into two continuous U shapes via the respective open ends of the inner cylinder 6,
Visible light from the phosphor layer 2 passes through the outer tube 1 and radiates outward. Reference numeral 7 denotes a case body fixed to the end of the outer tube valve 1, which houses electric parts such as a ballast and a starter (none of which are shown), and has an electrical connection to the electric parts at the tip. It has a cap 8 which is connected to the lamp and can be directly screwed into an incandescent lamp socket.

In the fluorescent lamp configured as described above, the stem 3 is also required to have the function of supporting the electrode 5 and the inner tube 6, so it must necessarily be flat and have a fairly large diameter. This makes stem molding extremely difficult and also weakens the strength. Therefore, it was practically impossible to form the stem 3 from glass. Therefore,
Various proposals have been made to use a metal plate or a ceramic plate having a thermal expansion coefficient close to that of the outer bulb 1 as the stem material.

However, when the stem 3 is formed of such a material, the force stem 3 and the outer tube bulb 1 are fixed together with the frit 4, but if this fixing work is done in a short time, the glass outer bulb 1 In the case of the metal stem 3 and the metal stem 3, the outer bulb 1 may be damaged due to the difference in heat conduction and the fact that the coefficients of thermal expansion do not completely match over a wide temperature range. That is, Fig. 2 shows a stem 3 made of a metal plate and an outer bulb 1 fixed inside the outer bulb receiving part 31 of the stem 3, but in this case, the lamp is heated during manufacturing. As a result, the metal stem 3, which has good thermal conductivity, rises in temperature before the glass outer bulb 1, so that tensile stress is applied to the outer bulb 1 in the radial direction.
Conversely, during cooling, compressive stress is applied to the outer bulb 1 in the direction of the center of the diameter of the outer bulb 1. The outer bulb 1 is unable to withstand the tensile stress, compressive stress, particularly tensile stress generated by this heating and cooling, and is damaged. Therefore, it was difficult to shorten the working time and it was not industrially practical.

This invention was made in view of the above circumstances,
A metal plate or a ceramic plate that closes the opening of the outer bulb is fixed to the outer bulb with an inorganic adhesive, and the opening end of the outer bulb is reduced in diameter and buried in at least the frit of the reduced diameter part. The outer bulb part is formed in a cylindrical shape, and even if the frit fixation time is shortened, accidents such as damage to the outer bulb can be prevented, and workability is improved to provide a highly industrial discharge lamp. It is.

An embodiment of the present invention will be described below with reference to FIG.

In the figure, reference numeral 1 denotes an outer bulb made of soda lime glass with a wall thickness of about 1 mm, and an open end 11 of the outer bulb 1 is a cylindrical body that forms the main part of the outer bulb 1. A reduced diameter portion 13 is formed which is smaller in diameter than 12, and a cylindrical portion 14 is further formed on the tip side of this reduced diameter portion 13. 3 is
A stainless steel stem with a plate thickness of approximately 0.5 mm, containing approximately 13% chromium and the remainder iron, and a recessed outer tube receiving portion 31 that accommodates the cylindrical portion 14 of the outer tube valve 1 at its peripheral edge.
It is formed by integrally bending. The outer bulb 1 and the stem 3 are hermetically sealed within the outer tube receiver 31 through the frit 4 so that the cylindrical portion 14 of the outer bulb 1 is buried in the frit 4. . Note that everything other than what is shown is the same as in FIG. 1.

In the discharge lamp of the above embodiment, the outer bulb 1
The reduced diameter portion 13 disperses and absorbs tensile and compressive stress on the outer bulb 1 caused by heating and cooling of the lamp, thereby weakening these stresses applied to the outer bulb 1.

However, in the above embodiment, the reduced diameter portion 1
If at least the part of the stem 3 that is buried in the frit 4 is not cylindrical, it will be difficult to position the stem 3 with the outer tube receiving part 31, and the sealing work with the frit 4 will be complicated, and the frit 4 will not be fixed evenly. As a result, the strength is weakened and cracks are likely to occur, resulting in a disadvantage of lowering the reliability of hermetic sealing.

FIG. 4 shows another embodiment different from the above-mentioned embodiment, in which the inclined surface 15 of the reduced diameter portion 13 is formed directly from the upper surface of the frit 4, and it is less likely to be damaged than the above-mentioned embodiment. This has the effect of increasing the strength against.

In addition, in the case where the stem material is made of forsterite ceramic (2MgO・SiO ₂ ), which has a thermal expansion coefficient similar to that of the soda lime glass outer tube, instead of 13 chromium stainless steel, the same applies to each of the above embodiments. It was confirmed that the same effect could be obtained.

Furthermore, in this embodiment, the main part of the outer valve 1 except for the open end 11 is cylindrical, but as shown in FIG. Of course, it can also be applied to other shapes such as.

As described above, the present invention includes a glass outer bulb having an opening and a metal or ceramic stem that closes the opening of the bulb, and the stem and the bulb are sealed with a frit. In the above-mentioned valve, the opening end of the valve is reduced in diameter, and at least the part of the reduced diameter part buried in the frit is formed into a cylindrical shape. Breakage accidents can be prevented, workability can be improved, and a discharge lamp with high industrial performance can be provided.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway perspective view of a conventional single-cap fluorescent lamp, Fig. 2 is an enlarged cross-sectional view showing the open end of the outer bulb of Fig. 1, and Fig. 3 is an embodiment of the present invention. FIGS. 4 and 5 are enlarged sectional views showing essential parts of other embodiments of the present invention. In the figure, 1 is an outer tube valve, 3 is a stem, 4 is a frit, 11 is an end portion, 13 is a reduced diameter portion, and 14 is a cylindrical portion. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A bulb made of glass having an opening, and a stem made of metal or ceramic that closes the opening of the bulb, and the stem and the bulb are sealed with an inorganic adhesive. A discharge lamp characterized in that the end portion of the bulb having the opening is reduced in diameter, and the reduced diameter portion is formed into a cylindrical shape at least at a portion buried in the inorganic adhesive. 2. The discharge lamp according to claim 1, wherein the diameter-reduced portion of the bulb is exposed from the inorganic adhesive and has an inclined surface.