JPS6362061B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a compact discharge lamp. Although incandescent light bulbs have lower lamp efficiency than discharge lamps such as fluorescent lamps, they are widely used as one of the mainstream lamps for indoor lighting because they provide a natural and favorable color rendering for the illuminated object. however,
With the recent movement toward energy conservation, the low efficiency of light bulbs has become a problem, and compact discharge lamps are being developed to replace incandescent light bulbs. The present inventor has already proposed a novel discharge lamp that can replace incandescent light bulbs in Japanese Patent Publication No. 57-37105. Its structure is shown in Figures 1a and 1b. 1 is a glass container consisting of a glass envelope 2 and a glass inner container 3. Glass envelope 2 and glass inner envelope 3
are overlapped and joined along the opening 4 thereof. and at least the glass inner container 3
A meandering groove 5 is formed in the groove 5, and tungsten coil electrodes 6, 7 similar to those in a normal fluorescent lamp are held at both ends of the meandering groove 5. The tungsten coil electrodes 6, 7 are supported by a support wire 8,
It is connected to external lead wires 10 and 11 via 9. In the above structure, the discharge is formed along the meandering groove 5 between both electrodes. A feature of this device is that a discharge groove is provided between the two curved glass bodies. Compared to conventional fluorescent lamps that use straight glass tubes, this allows the discharge groove to be relatively long and allows for a compact bulb-shaped exterior. In addition, regarding the structure, a phosphor 12 is coated on the inner surface of the glass envelope 2 and the outer surface of the glass inner envelope 3 at least in the portion corresponding to the discharge groove, and furthermore, the inside of the meandering groove 5 is coated with a phosphor 12. Just like a normal fluorescent lamp, it is filled with several Torr of rare gas, mainly argon, and excess mercury droplets. As a next step, the present inventor conducted various studies regarding the manufacture of the above-mentioned lamp. As a result, the following unexpected problems were found. (1) The glass envelope 3 provided with the meandering groove 5 is easily damaged during the lamp evacuation process or even after completion. This is because the mechanical strength of the glass envelope 3 has been reduced by providing the meandering groove 5, and the difference between the atmospheric pressure and the rare gas filling pressure inside the glass envelope causes the inside of the glass to deteriorate. This is due to the fact that the envelope 2 is subjected to so-called tensile stress in the outward direction. The reason why the glass envelopes of the outer bulbs of ordinary vacuum light bulbs and high-pressure sodium lamps do not break is thought to be because they are subjected to so-called compressive stress inward. In fact, the glass envelope 2 that is subjected to compressive stress is the same as the glass envelope 2 even though the wall thickness is the same.
It could not have been damaged sooner. Of course, by increasing the wall thickness of the glass, it was possible to suppress the breakage to some extent, but it is clear that an increase in the wall thickness results in an increase in the weight of the lamp, which is not desirable as a product. (2) In addition to damage to the glass envelope 3, the opening 4 where the glass envelope 2 and glass inner envelope 3 were joined
However, it is easy to crack whether it is welded or sealed with glass frit. This is because, as shown in FIG. 1, when two closely stacked glass bodies are joined, stress strain tends to remain. (3) In the lamp shown in FIG. 1, since discharge is formed only in the meandering groove 5, uneven brightness naturally occurs on the surface of the glass envelope 2 when the lamp is lit. It was also confirmed that this brightness unevenness is improved as the depth db of the meandering groove 5 becomes longer. In other words, as the depth db of the meandering groove 5 increases, the brightness of the surface portion of the glass envelope 2 where no discharge is formed increases relative to the brightness of the surface portion corresponding to the meandering groove 5. . However, in order to improve the brightness unevenness, the meandering groove 5
When the depth db is increased, the damage to the glass envelope 2 as described in item 1 increases, so it has been found that it is difficult to sufficiently improve the brightness unevenness. From the above results, it has become clear that if the structure of the lamp shown in FIG. 1 is used as it is, manufacturing efficiency will be poor and problems with lamp quality such as uneven brightness and breakage will remain. An object of the present invention is to provide a discharge lamp having a structure that solves the above-mentioned quality problems of the lamp. The present inventor has conducted various studies on structures that satisfy the above objectives. As a result, instead of joining the openings of the glass envelope and the glass inner container as in the past, by joining the newly added glass stem and the glass envelope, The desired discharge lamp could be realized. The present invention will be explained below based on illustrated embodiments. FIG. 2 shows a discharge lamp according to an embodiment of the present invention. In the figure, a glass inner envelope 3 having an opening at one end is superimposed along the inside of a glass envelope 2 having an opening 4 at one end, as in the conventional case. A meandering groove 5 is formed in the glass envelope 3, and a phosphor 12 is coated on the inner surface of the glass envelope 2 and the outer surface of the glass envelope 3. Then, the opening 4 of the glass envelope 2 and the peripheral portion 14 of the disk-shaped glass stem 13 are joined. In this case, the joining method may be either welding or sealing using glass frit. Further, the shape of the glass stem 13 may be any shape as long as at least the peripheral portion 14 is formed into a circular shape. The glass stem 13 has an exhaust pipe 15 in the center.
are provided, and support lines 8 and 9 are further sealed. Tungsten coil electrodes 6 and 7 filled with an electron emitting material are held at the tips of the support wires 8 and 9, respectively. Further, the other ends of the support wires 8 and 9 are connected to external lead wires 10 and 11, respectively. The entire interior of the glass container 1' is evacuated through an exhaust pipe 15, and is then filled with several Torr of rare gas, mainly argon, and excess mercury. In addition, as another method of enclosing mercury, as shown in FIG.
The cylindrical getter ribbon 16 filled in advance may be held, and after the exhaust pipe 15 is closed, the getter ribbon 16 may be heated to enclose mercury. This method has the advantage of not only being able to easily adjust the amount of mercury to be sealed, but also providing a so-called getter effect by the getter ribbon 16, thereby improving the lamp life. In particular, in this lamp, as is clear from the figure, there is a narrow gap, so there is a tendency for more gas to remain after exhaust compared to conventional fluorescent lamps, so the attachment of the getter ribbon has a favorable result. Gave. According to the above configuration, atmospheric pressure is no longer applied to the glass envelope 3, so it will not be damaged.
Also, the opening 4 of the glass envelope 2 and the glass inner envelope 3
Since they are not joined together, there is no possibility of cracking. Furthermore, regarding the dimensions of the meandering groove 5 of the glass envelope 3, there is no longer any need to worry about breakage, so the depth db of the meandering groove 5 can be made long. As a result, a discharge lamp with less uneven brightness was realized. Next, Table 1 shows the specifications of the discharge lamp having the structure shown in FIG. 2, and Table 2 shows its characteristics.

【table】

[Table] As shown in Table 2, the luminous flux with 30W input is
The value of 1450 lm indicates that the discharge lamp of the present invention is an energy-saving light source that can replace traditional incandescent lamps. Furthermore, it was confirmed that the above-mentioned problems did not occur in the discharge lamp of this example. As described above, the present invention can provide a discharge lamp that solves the conventional lamp quality problems.

[Brief explanation of drawings]

Figures 1a and b are a partially cutaway longitudinal cross-sectional view and a cross-sectional view taken along the line - of a conventional discharge lamp, Figure 2 is a partially cutaway longitudinal cross-sectional view of a discharge lamp according to an embodiment of the present invention, and Figure 3 is a partially cutaway vertical cross-sectional view showing an example of a glass stem of the same discharge lamp. 1'...Glass container, 2...Glass envelope,
3... Glass inner container, 4... Opening, 5... Meandering groove, 6, 7... Tungsten coil electrode, 8, 9
... Support wire, 10, 11 ... External lead wire, 12
...Fluorescent body, 13...Glass stem, 15...
Exhaust pipe.

Claims (1)

[Claims] 1. A glass envelope having an opening at one end is stacked along the inside of the glass envelope having an opening at one end, and at least a meandering groove for forming a discharge path is provided in the glass envelope. , holding electrodes at both ends of the groove, further applying a phosphor to at least a portion of the inner surface of the glass envelope or the outer surface of the glass inner vessel corresponding to the discharge path, and applying a phosphor to the inside of the groove. 1. A discharge lamp filled with rare gas and mercury, characterized in that a glass stem is joined to an opening of the glass envelope.