JP2788621B2 - Ring fluorescent lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an annular fluorescent lamp in which a plurality of annular arc tubes are arranged concentrically.

[0002]

2. Description of the Related Art Conventionally, ring-shaped fluorescent lamps have been widely used mainly for residential lighting. In particular, in order to obtain a high output, two or more individual ring-shaped fluorescent lamps are arranged in a stepped manner, and such ring-shaped fluorescent lamps are used by being attached to dedicated lighting equipment. . Therefore, since such a lighting fixture is thick and large , it is not economical and has a problem in that the degree of freedom is restricted also in terms of fixture design. In addition, 2
Even when a ring-shaped fluorescent lamp that can obtain high output equivalent to that of at least two ring-shaped fluorescent lamps is used alone , the ring-shaped fluorescent lamp itself becomes larger, and the lighting equipment also becomes larger.
The same problems as described above occur in terms of economy and design.

[0003]

In order to solve the problems of the conventional circular fluorescent lamps, such as above [0005], as shown in FIG. 12, two compact glass circular arc tube 2
The ring-shaped lamps 1 and 22 are arranged on the same plane and concentrically, and the respective ring-shaped arc tubes 21 and 22 are joined to each other by a bridge joint 23 made of a glass tube to form one discharge path inside. Fluorescent lamps have been proposed (Japanese Patent Application Laid-Open Nos. Hei 2-61956 and Hei 6-203798). In FIG. 12, 24 and 25 are electrodes. The present inventors have made various studies on these annular fluorescent lamps. As a result, in such a ring-shaped fluorescent lamp, the area of the non-light-emitting portion including the electrode attachment portion along the ring circumference, that is, the distance K shown in FIG. 12 is larger than that of the conventional ring-shaped fluorescent lamp. I understood. In addition, it was found that even when the base was provided, the light distribution characteristics along the ring circumference of the lamp deteriorated, and the base became larger, which also had a problem in terms of design. Further, since the lamp shape is compact and the lamp is operated with a relatively high load, the coolest point temperature in the arc tube which inevitably determines the mercury vapor pressure is in the optimum temperature range of 40 to 50 ° C. And the lamp luminous flux becomes lower than the maximum value that can be realized as a fluorescent lamp. Further, when the area of the non-light emitting portion is increased as described above, there is also a problem that the lamp light flux is reduced.

In order to solve the above-mentioned problems in the prior art, the present invention can reduce a non-light-emitting area, maintain a high lamp luminous flux, and have a light distribution characteristic along a ring circumference of the lamp. It is an object of the present invention to provide a compact, high-efficiency, high-output ring-shaped fluorescent lamp which is excellent in design and excellent in design.

[0005]

According to a first aspect of the present invention, there is provided a ring-shaped fluorescent lamp comprising a plurality of ring-shaped fluorescent lamps each having an electrode at one end and a closed portion at the other end. The tubes are arranged concentrically, and the other end portions of the plurality of annular light emitting tubes are joined by a bridge joint to form an inside.
An annular fluorescent lamp having one discharge path formed therein, wherein a distance from the bridge junction of the annular arc tube located outside of the plurality of annular arc tubes to the center of the end surface of the other end is L. ₁ (mm), where L ₂ (mm) is the distance from the bridge junction of the annular arc tube located inside to the center of the end face of the other end, the distance L ₁ is longer than the distance L _2. It is characterized by.

In the first configuration of the present invention, it is preferable that a plurality of annular arc tubes are arranged on the same plane. In the first configuration of the present invention, it is preferable that the relationship L ₁ ≧ 1.3L ₂ is satisfied.

In the first configuration of the present invention, it is preferable that one end of the ring-shaped arc tube located outside is longer than one end of the ring-shaped arc tube located inside. In the first configuration of the present invention, it is preferable that the shape of the tube tip on the bridge junction side is substantially axially symmetric with respect to the center axis of the annular arc tube.

Further, in the first configuration of the present invention, it is preferable that bending holding portions are provided on outer wall surfaces at both ends of the ring-shaped arc tube. In this case, it is preferable that a groove is provided on the inner wall surface of the ring-shaped arc tube at least on the tip side of the bending holding portion at the other end on the non-electrode side.

In the first configuration of the present invention, it is preferable that a base is provided to surround one end of each of the plurality of annular arc tubes. Further, in the first configuration of the present invention, the base is provided so as to surround both the one end and the other end of the plurality of ring-shaped arc tubes, and the other end of the ring-shaped arc tube located on the outside is provided. It is preferable to touch the outside air. In this case, it is preferable that the base is provided with a heat shielding member for thermally shielding one end and the other end of the ring-shaped arc tube.

In the first configuration of the present invention, it is preferable that the other end of the annular arc tube on the non-electrode side is sealed by a stem. In the second configuration of the ring-shaped fluorescent lamp according to the present invention, a plurality of ring-shaped arc tubes having an electrode at one end and a closed portion sealed at the other end with a stem are concentrically arranged on the same plane. And the other end portions of the plurality of ring-shaped arc tubes are joined by a bridge joint to form a single discharge path inside, and a coldest spot is formed at the other end portion. A ring-shaped fluorescent lamp, wherein a distance from the bridge junction of the ring-shaped arc tube located outside of the plurality of ring-shaped arc tubes to the center of the end face of the other end is L ₁ (mm) and located inside; Assuming that the distance from the bridge junction of the annular arc tube to the center of the end face of the other end is L ₂ (mm), the relationship of L ₁ ≧ 1.3L ₂ is satisfied, and A base surrounding the other end is provided, and the base is provided with the Point where
A vent is provided to allow the outer surface of the end of the ring-shaped arc tube to be exposed to the outside air, and a heat shielding member for heat-shielding the one end and the other end of the ring-shaped arc tube is provided. It is characterized by the following.

[0011]

According to the first configuration of the present invention, a plurality of ring-shaped arc tubes each having an electrode at one end and a closed portion at the other end are arranged concentrically. An annular fluorescent lamp in which one end of each of the plurality of annular arc tubes is joined by a bridge joint to form one discharge path therein, and which is located outside of the plurality of annular arc tubes. The distance from the bridge junction of the annular arc tube to the center of the end surface of the other end is L ₁ (mm), and the distance from the bridge junction of the annular arc tube located inside to the center of the end surface of the other end is L1 (mm). when the distance was L ₂ (mm), the distance L ₁ is characterized longer than the distance L _2, coldest portion is formed at the other end of the ring-shaped arc tube located outside its Conclusion
As a result, the temperature can be easily controlled to have an optimal mercury vapor pressure corresponding to the maximum value of the lamp luminous flux.

In the first configuration of the present invention,
According to a preferred example in which the plurality of ring-shaped arc tubes are arranged on the same plane, the lighting fixture can be made thin.

[0013] In the first configuration of the present invention,
According to a preferred example that satisfies the relationship of L ₁ ≧ 1.3L _{2, the} coldest spot at which the optimal mercury vapor pressure is given to the tip of the ring-shaped arc tube located outside on the bridge junction side is ensured. Can be formed.

In the first configuration of the present invention,
According to a preferred example in which one end of the ring-shaped arc tube located on the outside is longer than one end of the ring-shaped arc tube located on the inside, the effective light emission length of the ring-shaped fluorescent lamp is increased, thereby also increasing the lamp luminous flux. It is possible to do. Further, when the effective light emission length of the ring-shaped fluorescent lamp is increased, the non-light-emitting area of the ring-shaped fluorescent lamp is reduced, so that a light-distribution characteristic is improved and a compact ring-shaped fluorescent lamp excellent in design is realized.

[0015] In the first configuration of the present invention,
According to a preferred example in which the shape of the tube end on the bridge junction side is substantially axially symmetric with respect to the center axis of the annular arc tube, the strength of the tube end on the bridge junction side does not decrease.

In the first configuration of the present invention,
According to a preferred example in which the holding portion for bending is provided on the outer wall surface at both ends of the ring-shaped arc tube, the holding portion for bending of the ring-shaped arc tube can be firmly held in the lamp manufacturing process. The bending accuracy of the pipe can be improved. Further, in this case, according to a preferred example in which the groove is provided on the inner wall surface on the tip side of at least the bending holding portion at the other end on the non-electrode side of the annular arc tube, the coldest spot is formed in the groove. And the temperature can be kept at an optimum value.

In the first configuration of the present invention,
According to a preferred example in which the base is provided so as to surround one end of the plurality of annular arc tubes, the heat of the electrodes is transmitted to the other end of the annular arc tube, and the temperature at the coldest spot is excessively adjusted from the optimal region. Never rise. As a result, it is possible to prevent the lamp luminous flux from lowering.

Further, in the first configuration of the present invention,
Mouthpiece provided together surround the one end and the other end of the plurality of said ring-shaped light emitting tube, and, according to a preferable embodiment of the second end portion of the ring-shaped arc tube positioned outside is touching the external air, a plurality And the temperature of the coldest spot can be prevented from rising excessively from the optimal region, and as a result, the lamp luminous flux can be prevented from lowering. it can. Further, in this case, according to a preferred example in which the base is provided with a heat shielding member that thermally shields one end and the other end of the ring-shaped arc tube, the ring-shaped light emission in which the coldest spot is formed from the electrode. Transmission of heat to the other end of the tube can be suppressed. As a result, it is possible to more reliably prevent the temperature at the coldest spot from excessively rising from the optimum region, and it is possible to reliably prevent the luminous flux of the lamp from decreasing.

Further, in the first configuration of the present invention,
According to a preferred example in which the other end on the non-electrode side of the ring-shaped arc tube is sealed by the stem, the strength of the other end on the non-electrode side is improved as compared with the conventional structure. In the case of the conventional structure, since the end portion is formed by melting a part of the arc tube, the thickness of the other end on the non-electrode side becomes thin especially in an arc tube having a large tube diameter. On the other hand, in the case of sealing with the stem, the end can be firmly sealed, and inconveniences such as cracking of the end at the time of bending the arc tube or after completion of the lamp can be eliminated. . Further, in the case of sealing with a stem, the manufacturing is relatively easy as compared with the case of the conventional structure, and the manufacturing can be performed using the conventional manufacturing equipment.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
Will be explained. First Embodiment FIG. 1 is a partially cutaway front view showing a first embodiment of a ring-shaped fluorescent lamp according to the present invention, and FIG. 2 shows a structure around a bridge junction of the ring-shaped fluorescent lamp of FIG. It is a partially notched front view. As shown in FIGS. 1 and 2, two ring-shaped light emitting tubes 1 and 2 made of glass are arranged on the same plane and concentrically. 3, 4 are attached. In addition, ring-shaped arc tubes 1
The other ends 11 and 12 are closed. The vicinity of the other end portions 11 and 12 of the annular arc tubes 1 and 2 is joined by a bridge joint portion 5 made of a glass tube, thereby forming one discharge path between the electrodes 3 and 4 inside the arc tube. Have been. A rare earth phosphor 6 is applied to the inner surfaces of the ring-shaped light emitting tubes 1 and 2, and mercury and a rare gas such as argon and neon as a buffering gas and mercury (200) are provided in the ring-shaped light emitting tubes 1 and 2. ５００500 Pa).
Note that mercury may be enclosed as an amalgam alloy such as zinc-mercury.

In the ring-shaped fluorescent lamp of this embodiment, the outer diameters of the ring-shaped light emitting tubes 1 and 2 are 14 mm, the outer diameter of the ring-shaped light emitting tube 1 located on the outer side is 150 mm, and the diameter of the ring-shaped light emitting tube 2 located on the inner side is 150 mm. It has a compact shape with a ring inner diameter of 90 mm, and is designed to light up at a lamp input of 25 W.

The distance L from the end of the bridge joint 5 to the center of the end face of the other end 11 of the annular arc tube 1 located outside.
₁ is 11 mm, and the distance L ₂ from the end of the bridge joint 5 to the center of the end face of the other end 12 of the annular arc tube 2 located inside is 6 mm. The center-to-center distance l between both ends of the ring-shaped arc tube 1 located outside is 18 mm.
When this ring-shaped fluorescent lamp was turned on at a lamp input of 25 W using an inverter circuit of 50 kHz, a color temperature of 3 W
A high luminous flux value of 1620 lm was obtained with an emission color of 000 Kelvin. When the temperatures of the circular arc tubes 1 and 2 were measured, the coldest spot was formed at the other end portion 11 of the annular arc tube 1 located outside.
At the time of 5W lighting (room temperature of 25 ° C.), the temperature was 45 ° C. corresponding to the optimum mercury vapor pressure at which a maximum luminous flux value was obtained.

The inventor of the present invention has proposed a ring-shaped arc tube 2 located outside the end of the bridge joint 23 as shown in FIG.
1, the distance L ₁ ′ to the center of the end face of the other end 26 and the annular arc tube 2 located inside from the end of the bridge joint 23.
A conventional ring-shaped fluorescent lamp having the same distance L ₂ ′ to the center of the end face of the other end 27 of the _second was manufactured, and various characteristics of the lamp were measured. In this lamp, the distances L ₁ ′, L ₁ ′ and L ₂ ′ for keeping the temperature of the coldest spot at the tip of the arc tube in the optimal region
₂ 'was 13 mm. This lamp was connected to a lamp input 25 W using a 50 kHz inverter circuit in the same manner as described above.
When turned on, the lamp luminous flux showed a value of 1490 lm. That is, it was found that the ring-shaped fluorescent lamp of the present embodiment shown in FIGS. 1 and 2 has a luminous flux value that is 130 lm (about 9%) higher than that of the conventional ring-shaped fluorescent lamp shown in FIG. The reason why such a high luminous flux value was obtained is that the distance L ₁ from the end of the bridge junction 5 to the center of the end face of the other end 11 of the annular arc tube 1 located outside is determined by the distance L ₁ of the bridge junction 5. The other end 12 of the ring-shaped arc tube 2 located inside from the end
By made longer than the distance L ₂ to the end surface central portion of the, coldest point portion is formed at the other end 11 of the ring-shaped light-emitting tube 1 which is located outside, so that its temperature, the maximum value of the lamp luminous flux This is because it was possible to easily control such that the optimum mercury vapor pressure was obtained. Further, the ring-shaped fluorescent lamp of the present embodiment has a non-light-emitting area including the electrode end portions as shown in FIG.
2 is smaller than the conventional one shown in FIG. 2, and the light distribution characteristics along the circumference of the ring are improved accordingly, which is preferable in terms of lamp design.

As shown in FIGS. 1 and 2, the electrode end of the ring-shaped arc tube 1 located on the outside is deviated by a distance S from the electrode end of the ring-shaped arc tube 2 located on the inside. In order to investigate the effect when the ring-shaped fluorescent tube 1 located on the outside is longer than the ring-shaped light-emitting tube 2 located on the inside, FIG.
As shown in the figure, a lamp was prepared in which the electrode 3 of the ring-shaped arc tube 1 and the electrode 4 of the ring-shaped arc tube 2 were arranged in parallel, and various characteristics of the lamp were measured. Connect this lamp to 5
When the lamp was turned on with a lamp input of 25 W using an inverter circuit of 0 kHz, the lamp luminous flux showed a value of 1580 lm. Thus, the ring-shaped fluorescent lamp of the present embodiment shown in FIGS. 1 and 2 has a longer effective light emission length and a luminous flux value of 40 lm as an effect of displacing the electrode end of the ring-shaped arc tube 1 located on the outside. (About 3%). Further, also in this case, it is clear that the non-light-emitting area is reduced and the light distribution characteristics are improved, which is preferable in terms of lamp design.

The bridge joint 5 of the annular arc tubes 1 and 2
As shown in FIG. 4, the other end portions 11 and 12 on the side may have a shape in which a tube center portion protrudes. However, as shown in FIG. 5, when the shapes of the other end portions 11 and 12 of the ring-shaped arc tubes 1 and 2 are asymmetric with respect to the tube center axis, the strength of the glass tip portion is extremely reduced, which is not preferable. In any case, it is necessary to process the tube tip into a shape that is substantially symmetrical with respect to the tube center axis.

<Second Embodiment> In this embodiment, a structure similar to that of the first embodiment (FIGS. 1 and 2) is employed, and a compact ring-shaped fluorescent lamp having a lamp input of 60 W is manufactured. did. Each of the dimensions of the annular fluorescent lamp is such that the outer diameter of the annular arc tubes 1 and 2 is 20 mm, the outer diameter of the annular arc tube 1 located on the outside is 240 mm, and the inner diameter of the annular arc tube 2 located on the inside is 155 mm. The distance L1 from the end of the bridge joint 5 to the center of the end face of the other end 11 of the ring-shaped arc tube ₁ is 17 mm, and the distance from the end of the bridge joint 5 to the center of the end face of the other end 12 of the ring-shaped arc tube 2. distance L ₂ to the section is 10 mm, center-to-center distance l of the both end portions of the ring-shaped arc tube 1 is 22 mm. When this lamp was turned on with a lamp input of 60 W using an inverter circuit of 50 kHz, a high luminous flux value of 4530 lm was obtained.

With respect to the lamps of the first and second embodiments, in particular, the distance L from the end of the bridge joint 5 of the annular arc tube 1 located outside to the center of the end face of the other end 11 is shown.
_When the luminous flux value was measured while changing ₁ variously, the distance L ₁ at which the maximum luminous flux value was obtained was in the range of 0.5 d ≦ L ₁ ≦ 1.3 d, where d was the outer diameter of the annular arc tubes 1 and 2. I found it. Also, the other end 1 of the ring-shaped arc tube 1 located on the outside
To reliably form a coldest point which gives the optimum mercury vapor pressure to 1, the distance L ₁ and the distance L ₂ has been found that should satisfy L ₁ ≧ 1.3 L ₂ the relationship.

Third Embodiment In the present embodiment, a ring-shaped fluorescent lamp in which a base is attached to the ring-shaped fluorescent lamp of the first and second embodiments will be described.

FIG. 6 shows a third embodiment of the annular fluorescent lamp according to the present invention.
FIG. 7 is a front view showing another example of the structure around the bridge joint of the third embodiment of the ring-shaped fluorescent lamp according to the present invention. . In the ring-shaped fluorescent lamp shown in FIG. 6, one end (the electrodes 3 and 4 side) of the ring-shaped light emitting tubes 1 and 2 are surrounded by the base 7, and the other ends 11 and 12 are separated from the base 7 and exposed to the outside air. It has been touched. On the other hand, in the annular fluorescent lamp shown in FIG. 7, one end (electrodes 3 and 4 side) and the other ends 11 and 12 of the annular arc tubes 1 and 2 are surrounded by a base 8. In this case, the base 8 is provided with a vent 10 for allowing the outer surface of the other end 11 of the ring-shaped arc tube 1 where the coldest spot is located to come into contact with the outside air. In this manner, in a state where the other end 11 of the ring-shaped arc tube 1 located outside is exposed to the outside air,
By attaching the bases 7 and 8, the heat of the electrodes 3 and 4 is not transmitted to the other end 11 of the ring-shaped light emitting tube 1 and does not excessively raise the temperature of the coldest spot. Can be prevented. In particular, as shown in FIG. 7, if the base 8 is attached so as to surround both ends (the electrodes 3 and 4) and the other ends 11 and 12 of the ring-shaped arc tubes 1 and 2, the ring-shaped arc tubes 1 and 2 can be assembled. It can be kept stable.

By the way, as shown in FIG. 8, the ring-shaped light emitting tube 1 is provided by using a base 9 having no vent hole for allowing the other end 11 of the ring-shaped light emitting tube 1 located outside to come into contact with the outside air.
In the case of surrounding both end portions of the first and second embodiments, the distance L ₁ from the end of the bridge joint portion 5 of the ring-shaped arc tube 1 located outside to the center of the end face of the other end 11 is set to the first and second embodiments. By making the lamp longer than in the case of the example, it is necessary to correct the temperature of the coldest spot at the tip portion when assembled as a completed lamp so that the temperature does not excessively rise from the optimum region. Therefore, when the base 9 in FIG. 8 is used, the bases 7 and 8 in FIGS.
The effective emission length of the lamp is shorter than when using
The lamp luminous flux decreases.

<Fourth Embodiment> FIG. 9 is a partially cutaway front view showing a structure around a bridge junction of a fourth embodiment of a ring-shaped fluorescent lamp according to the present invention. As shown in FIG. 9, the base 13 includes the ring-shaped arc tubes 1, 2
Is mounted so as to surround one end (electrodes 3 and 4 side) and the other ends 11 and 12. The base 13 has the coldest point.
A vent 10 that allows the other end 11 of the ring-shaped light emitting tube 1 where the portion is located to come into contact with the outside air, and one end (the electrodes 3 and 4 side) and the other ends 11 and 12 of the ring-shaped light emitting tubes 1 and 2 are heat shielded. And a heat shielding partition 16 which is a heat shielding member. According to this configuration, heat transfer from the electrodes 3 and 4 to the other end portion 11 of the ring-shaped arc tube 1 where the coldest spot is formed can be suppressed by the heat shielding partition 16, so that the coldest spot is formed. Excessive rise in the temperature of the portion from the optimum region can be more reliably prevented than in the case of the third embodiment.
As a result, it is possible to reliably prevent the lamp luminous flux from lowering.

Fifth Embodiment FIG. 10 is a partially cutaway front view showing an example of a structure around a bridge junction of a fifth embodiment of the annular fluorescent lamp according to the present invention. As shown in FIG. 10, bending holding portions 20 are provided on outer wall surfaces of both ends of the ring-shaped arc tubes 1 and 2. In addition, at least the other end portions 11 and 12 on the non-electrode side of the ring-shaped arc tubes 1 and 2 are provided with a groove portion 19 on the inner wall surface on the tip side with respect to the bending holding portion 20. The other configuration is the fourth
Since this embodiment is the same as the embodiment (FIG. 9), the same members are denoted by the same reference numerals and description thereof will be omitted. According to this configuration, the bending holding portions 20 of the ring-shaped light emitting tubes 1 and 2 can be firmly held in the lamp manufacturing process, so that the bending accuracy of the ring-shaped light emitting tubes 1 and 2 can be improved. Further, according to this configuration, the coldest spot is formed in the groove 19, and the temperature thereof can be maintained at the optimum value.

As shown in FIG. 11, when the other end portions 11 and 12 on the non-electrode side are sealed by the same stem as the end portion on the electrode side, the end structure as shown in FIG. Thus, the strength of the other end portions 11 and 12 on the non-electrode side is improved. In the case of the end structure shown in FIG. 10, since the end portion is formed by melting a part of the arc tube, the thickness of the other end portions 11 and 12 on the non-electrode side becomes thin especially in an arc tube having a large tube diameter. Would. On the other hand, in the case of sealing with the stem, the end can be firmly sealed, and inconveniences such as cracking of the end at the time of bending the arc tube or after completion of the lamp can be eliminated. . Further, in the case of sealing with a stem, manufacture is relatively easy as compared with the case of the end structure shown in FIG.
It can be manufactured using conventional manufacturing equipment.

[0034]

As described above, according to the present invention,
A compact, high-efficiency, high-output ring-shaped lamp having a high luminous flux value, good light distribution characteristics, and excellent design is realized.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing a first embodiment of a ring-shaped fluorescent lamp according to the present invention.

FIG. 2 is a partially cutaway front view showing a structure around a bridge junction of the annular fluorescent lamp of FIG. 1;

FIG. 3 is a front view showing a structure around a bridge junction of a ring-shaped fluorescent lamp manufactured as a comparative example in the first embodiment of the present invention.

FIG. 4 is a front view showing another example of the structure around the bridge junction of the first embodiment of the ring-shaped fluorescent lamp according to the present invention.

FIG. 5 is a front view showing a structure around a bridge junction of a ring-shaped fluorescent lamp manufactured as a comparative example with respect to FIG. 4 in the first embodiment of the present invention.

FIG. 6 is a front view showing an example of a structure around a bridge junction of a third embodiment of the ring-shaped fluorescent lamp according to the present invention.

FIG. 7 is a front view showing another example of the structure around the bridge junction of the third embodiment of the annular fluorescent lamp according to the present invention.

FIG. 8 is a front view showing a structure around a bridge junction of a ring-shaped fluorescent lamp manufactured as a comparative example with respect to FIGS. 6 and 7 in the third embodiment of the present invention.

FIG. 9 is a partially cutaway front view showing a structure around a bridge junction of a fourth embodiment of the ring-shaped fluorescent lamp according to the present invention.

FIG. 10 is a partially cutaway front view showing an example of a structure around a bridge joint of a fifth embodiment of the ring-shaped fluorescent lamp according to the present invention.

FIG. 11 is a partially cutaway front view showing another example of the structure around the bridge junction of the fifth embodiment of the annular fluorescent lamp according to the present invention.

FIG. 12 is a partially cutaway front view showing a conventional annular fluorescent lamp.

[Explanation of symbols]

 1, 2 annular arc tube 3, 4 electrode 5 bridge joint 6 phosphor 7, 8, 9, 13 base 10 vent 11, 12 (non-electrode side) other end 16 heat shielding member 19 groove 20 bending holding unit

Continuation of the front page (72) Inventor Masatsugu Sangen 1-1, Sachimachi, Takatsuki City, Osaka Prefecture Inside Matsushita Electronics Corporation (56) References JP-A-6-203798 (JP, A) JP-A-2- 61956 (JP, A) JP-A-55-133744 (JP, A) JP-A-59-86656 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01J 61/32 H01J 5 / 50

Claims (12)

(57) [Claims] 1. A has an electrode at one end, a plurality of annular arc tube having a closed portion at the other end is arranged concentrically, the double
And the other end near the number of ring-shaped arc tube is joined by a bridge junction, a circular fluorescent lamp in which one discharge path formed therein, the ring-shaped located outside of the plurality of ring-shaped arc tube The distance from the bridge junction of the arc tube to the center of the end face of the other end is L ₁ (mm), and the distance from the bridge junction of the annular arc tube located inside to the center of the end face of the other end. Is L ₂ (mm), the distance L
The circular fluorescent lamp _1, wherein longer than the distance L _2. 2. The ring-shaped fluorescent lamp according to claim 1, wherein a plurality of ring-shaped arc tubes are arranged on the same plane. 3. The ring-shaped fluorescent lamp according to claim 1, wherein the relationship L ₁ ≧ 1.3L ₂ is satisfied. 4. One end of an annular arc tube located outside is:
2. A lamp according to claim 1, wherein the length is longer than one end of the annular arc tube located inside.
The ring-shaped fluorescent lamp according to any one of claims 1 to 3. 5. The shape of the tube tip on the bridge joint side is:
2. The ring-shaped arc tube is substantially axially symmetric with respect to a central axis.
5. The ring-shaped fluorescent lamp according to any one of items 1 to 4. 6. The ring-shaped fluorescent lamp according to claim 1, wherein bending holding portions are provided on outer wall surfaces of both ends of the ring-shaped arc tube. 7. The ring-shaped fluorescent lamp according to claim 6, wherein a groove is provided on the inner wall surface of the ring-shaped arc tube at least on the tip side of the bending holding portion at the other end on the non-electrode side. 8. The ring-shaped fluorescent lamp according to claim 1, further comprising a base surrounding one end of the plurality of ring-shaped arc tubes. 9. A plurality of ring-shaped light emitting tubes, wherein one end and the other end of the ring-shaped light emitting tube are surrounded by a base, and the other end of the ring-shaped light emitting tube located outside is exposed to the outside air. ~
8. The ring-shaped fluorescent lamp according to any one of 7. 10. The ring-shaped fluorescent lamp according to claim 9, wherein the base is provided with a heat-shielding member for heat-shielding one end and the other end of the ring-shaped arc tube. 11. The annular fluorescent lamp according to claim 1, wherein the other end on the non-electrode side of the annular arc tube is sealed with a stem. 12. an electrode at one end, a plurality of annular arc tube is arranged concentrically on the same plane with the closed portion sealed by a stem at the other end, the plurality of annular arc tube Near the other end is joined by a bridge joint,
An annular fluorescent lamp in which one discharge path is formed inside and a coldest spot is formed at the other end.
A distance from the bridge junction of the outer ring-shaped arc tube of the plurality of ring-shaped arc tubes to the center of the end face of the other end is L ₁ (mm), and the bridge junction of the ring-shaped arc tube located inside is L ₁ (mm). When the distance from the end to the center of the end face of the other end is represented by L ₂ (mm), a relationship of L ₁ ≧ 1.3L ₂ is satisfied, and a base surrounding the one end and the other end is provided. The base is provided with the coldest spot .
A vent that allows the outer surface of the end of the annular arc tube to come into contact with the outside air, and a heat shielding member that thermally shields the one end and the other end of the annular arc tube are provided. Characteristic ring-shaped fluorescent lamp.