JPH08236075A - Ring-shaped fluorescent lamp - Google Patents

Abstract

PURPOSE: To provide a compact, highly efficient and high output ring-shaped fluorescent lamp whose lamp light flux can be maintained high. CONSTITUTION: Ring-shaped light emitting tubes 1 and 2 are arranged in a concentrically circular form on the same plane. Electrodes 3 and 4 are installed in respective one end parts of the ring-shaped light emitting tubes 1 and 2. The other end parts 11 and 12 of the ring-shaped light emitting tubes 1 and 2 are respectively blocked up. The vicinities of the other end parts 11 and 12 of the ring-shaped light emitting tubes 1 and 2 are joined together by a bridge joining part 5, and a single discharge passage is formed between the electrodes 3 and 4 inside of the light emitting tubes. A tube outside diameter of the ring-shaped light emitting tubes 1 and 2 is respectively set, for example, in 14mm, and a ring outside diameter of the ring-shaped light emitting tube 1 positioned outside is set in 150mm, and a ring inside diameter of the ring shaped light emitting tube 2 positioned inside is set in 90mm, and they are lighted in lamp input of 25W. The tube outside diameter of the ring-shaped light emitting tubes 1 and 2 is denoted by (d), a distance L up to an end surface central part of the other end parts 11 and 12 of the ring-shaped light emitting tubes 1 and 2 from an end part of the bridge joining part 5 is set in a range of (0.5d<=Lη1.3d).

Description

Detailed Description of the Invention

[0001]

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

[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 high output, one in which two or more individual ring-shaped fluorescent lamps are arranged in different stages is used, and such ring-shaped fluorescent lamps are used by being attached to a dedicated lighting fixture. . Therefore, since such a lighting fixture becomes thick and large, it is not economical and has a problem that the degree of freedom is restricted in terms of the design of the fixture. further,
Even if one ring-shaped fluorescent lamp, which can provide the same high output as two or more ring-shaped fluorescent lamps, is used, the ring-shaped fluorescent lamp itself becomes large and the lighting equipment also becomes large, which is economical and design. Then, the same problem as described above occurs.

[0003]

In order to solve the above-mentioned problems of the conventional annular fluorescent lamp, two compact glass annular arc tubes are arranged on the same plane and concentrically, A ring-shaped fluorescent lamp has been proposed in which each ring-shaped arc tube is bonded to each other by a bridge-bonded part made of a glass tube to form one discharge path therein (Japanese Patent Laid-Open Nos. 2-61956 and 6-6). -203798). The present inventors have made various studies on these ring-shaped fluorescent lamps. As a result, in such a ring-shaped fluorescent lamp, the lamp shape is compact, and since the lamp is lit at a relatively high load, the coldest spot temperature in the arc tube that determines the mercury vapor pressure is inevitable. There is a problem that the temperature rises above the optimum temperature range of 40 to 50 ° C. and the luminous flux of the lamp falls below the maximum value that can be originally realized as a fluorescent lamp.

In order to solve the above problems in the prior art, it is an object of the present invention to provide a ring-shaped fluorescent lamp which is capable of maintaining a high luminous flux of the lamp and which is compact and has high efficiency and high output.

[0005]

In order to achieve the above object, a first structure of a ring-shaped fluorescent lamp according to the present invention has a plurality of ring-shaped fluorescent lamps having an electrode at one end and a closed portion at the other end. The arc tubes are arranged concentrically, and the vicinity of the other ends of the plurality of ring-shaped arc tubes are joined by a bridge joint to form one discharge path inside and the other end is cooled at the lowest temperature. A ring-shaped fluorescent lamp having spots formed therein, wherein a distance from an end of the bridge joint to a center of an end face of the other end is L (mm), and an outer diameter of the ring-shaped arc tube is d (m).
m), the relationship of 0.5d ≦ L ≦ 1.3d is satisfied.

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

In the first structure of the present invention, it is preferable that the other end of the ring-shaped arc tube on the non-electrode side is sealed by a stem. A second configuration of the ring-shaped fluorescent lamp according to the present invention is such that a plurality of ring-shaped arc tubes, each having an electrode at one end and a closed part at the other end, are concentrically arranged, The vicinity of the other end of the arc tube is joined by a bridge joint to form a single discharge path inside, a coldest spot is formed at the other end, and the one end and the other A ring-shaped fluorescent lamp having a base that surrounds at least one of the ends, wherein the coldest spot is in contact with the outside air.

In the second structure of the present invention, it is preferable that a plurality of ring-shaped arc tubes are arranged on the same plane. In the second configuration of the present invention, the distance from the end of the bridge joint to the center of the end face of the other end is L (mm), and the outer diameter of the ring-shaped arc tube is d (mm).
Then, it is preferable to satisfy the relationship of 0.5d ≦ L ≦ 1.3d.

Further, in the above-mentioned second structure of the present invention, it is preferable that the base is provided so as to be separated from the coldest spot of the other end. Further, in the second configuration of the present invention, a mouthpiece is provided so as to surround one end portion and the coldest spot location of the other end, and the mouthpiece is exposed to the outside air. It is preferable that a ventilation hole is provided.

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

In the second structure of the present invention, it is preferable that the other end of the ring-shaped arc tube on the non-electrode side is sealed by a stem. The third configuration of the ring-shaped fluorescent lamp according to the present invention is such that a plurality of ring-shaped arc tubes having an electrode at one end and a closed part at the other end are concentrically arranged, The vicinity of the other end of the arc tube is joined by a bridge joint to form a single discharge path inside, a coldest spot is formed at the other end, and the one end and the other A ring-shaped fluorescent lamp having a base that surrounds at least one of the ends, wherein the base is provided with a heat-shielding member that thermally shields the one end and the other end of the ring-shaped arc tube. Is characterized by.

In the third structure of the present invention, it is preferable that a plurality of ring-shaped arc tubes are arranged on the same plane. In the third configuration of the present invention, the distance from the end of the bridge joint to the center of the end face of the other end is L (mm), and the outer diameter of the ring-shaped arc tube is d (mm).
Then, it is preferable to satisfy the relationship of 0.5d ≦ L ≦ 1.3d.

In the third structure of the present invention, the die is provided so as to surround one end portion and the coldest spot portion of the other end portion, and the coldest spot portion is provided on the die. It is preferable that a vent hole is provided to allow the air to come into contact with the outside air.

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

In the third structure of the present invention, it is preferable that the other end of the ring-shaped arc tube on the non-electrode side is sealed by a stem. In the fourth configuration of the ring-shaped fluorescent lamp according to the present invention, a plurality of ring-shaped arc tubes each having an electrode at one end and a closing part sealed by a stem at the other end are concentric on the same plane. Are arranged in a circular shape, the vicinity of the other ends of the plurality of ring-shaped arc tubes are joined by a bridge joint, and one discharge path is formed inside, and the coldest spot is formed at the other end. When the distance from the end of the bridge junction to the center of the end face of the other end is L (mm) and the outer diameter of the ring arc tube is d (mm), 0.5d ≦ L ≦ 1.3d is satisfied, and a mouthpiece surrounding the one end portion and the other end portion is provided, and the mouthpiece is ventilated to expose the coldest spot location to the outside air. A mouth is provided and heat shields the one end and the other end of the ring-shaped arc tube. Wherein the shield member is provided.

[0016]

According to the first aspect of the present invention, a plurality of ring-shaped arc tubes having an electrode at one end and a closing portion at the other end are arranged concentrically, and A ring-shaped fluorescent lamp in which the vicinity of the other end of the ring-shaped arc tube is joined by a bridge joint to form one discharge path inside and the coldest spot is formed at the other end. When the distance from the end of the bridge joint to the center of the end face of the other end is L (mm) and the outer diameter of the annular arc tube is d (mm), 0.5d ≦ L ≦ Since the characteristic of 1.3d is satisfied, the temperature of the coldest spot can be maintained in the region where the mercury vapor pressure in the arc tube is optimum, and the maximum value of the lamp luminous flux can be easily obtained. You can

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

Further, in the first configuration of the present invention,
According to the preferable example in which the curved holding portions are provided on the outer wall surfaces of both ends of the ring-shaped arc tube, the curved holding portions 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 preferable example in which the groove portion is provided on the inner wall surface of the annular arc tube at least on the other end portion on the non-electrode side on the tip side of the holding portion for bending, the coldest spot is formed on the groove portion. Therefore, the temperature can be maintained at the optimum value.

In addition, in the first configuration of the present invention,
According to the preferable example in which the other end of the ring-shaped arc tube on the non-electrode side is sealed by the stem, the strength of the other end on the non-electrode side is improved as compared with the case of 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 portion on the non-electrode side becomes thin especially in the 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 bending of the arc tube and cracking of the end after completion of the lamp can be eliminated. . Further, in the case of sealing with the 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.

According to the second aspect of the present invention,
A plurality of ring-shaped arc tubes having an electrode at one end and a closed portion at the other end are arranged concentrically, and the other ends of the plurality of ring-shaped arc tubes are joined by a bridge joint portion, A ring-shaped fluorescent lamp having a discharge path formed therein, a coldest spot formed at the other end, and a base surrounding at least one of the one end and the other end. It is characterized in that the coldest spot is exposed to the outside air, so that the heat of the electrode is transferred to the end portion on the side of the bridge junction to raise the temperature of the coldest spot excessively from the optimum region. There is no. As a result, it is possible to prevent the luminous flux of the lamp from decreasing.

In the second structure of the present invention,
According to a preferable example in which the base is provided separately from the coldest spot of the other end, it is possible to create a state where the coldest spot is in contact with the outside air.

Further, in the above-mentioned second structure of the present invention,
According to a preferred example in which the mouthpiece is provided so as to surround one end portion and the coldest spot location of the other end portion, and the mouthpiece is provided with a vent hole for exposing the coldest spot location to the outside air. For example, it is possible to create a state where the coldest spot is in contact with the outside air while stably holding a plurality of ring-shaped arc tubes.

In the second structure of the present invention,
According to a preferred example in which the coldest spot is formed on the outer ring-shaped arc tube of the plurality of ring-shaped arc tubes, the non-luminous area at the end of the arc tube is reduced to obtain a high luminous flux value. be able to.

According to the third aspect of the present invention,
A plurality of ring-shaped arc tubes having an electrode at one end and a closed portion at the other end are arranged concentrically, and the other ends of the plurality of ring-shaped arc tubes are joined by a bridge joint portion, A ring-shaped fluorescent lamp having a discharge path formed therein, a coldest spot formed at the other end, and a base surrounding at least one of the one end and the other end. It is characterized in that the base is provided with a heat shielding member that thermally shields the one end and the other end of the ring-shaped arc tube, so that heat from the electrode to the coldest spot is Transmission can be suppressed. As a result, it is possible to prevent the temperature at the coldest spot from rising excessively from the optimum region, so that it is possible to prevent the luminous flux of the lamp from decreasing.

[0025]

EXAMPLES The present invention will be described in more detail below with reference to examples. <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 joint portion of the ring-shaped fluorescent lamp of FIG. It is a partially notched front view. As shown in FIG. 1 and FIG. 2, two glass ring-shaped arc tubes 1 and 2 are arranged on the same plane and concentrically, and an electrode is provided at one end of each of the ring-shaped arc tubes 1 and 2. 3 and 4 are attached. The other ends 11 and 12 of the ring-shaped arc tubes 1 and 2 are closed. The vicinity of the other ends 11 and 12 of the ring-shaped arc tubes 1 and 2 are joined by a bridge joint 5 made of a glass tube, whereby a discharge path is formed between the electrodes 3 and 4 inside the arc tube. Has been done. The inner surface of the arc tubes 1 and 2 is coated with a rare earth phosphor 6, and the ring-shaped arc tubes 1 and 2 contain mercury and a rare gas such as argon and neon as a starting gas and a buffer gas (200 to 200). 500 Pa) is enclosed. The mercury may be enclosed as an amalgam alloy such as zinc-mercury.

In the ring-shaped fluorescent lamp of this embodiment, the ring-shaped arc tubes 1 and 2 each have an outer diameter d of 14 mm, the outer ring-shaped arc tube 1 has an outer ring diameter of 150 mm, and the inner ring-shaped arc tube 2 has an outer ring diameter d of 150 mm. It has a compact ring inner diameter of 90 mm and is designed to be lit with a lamp input of 25 W.

The distance L from the end of the bridge joint portion 5 to the center of the end faces of the other ends 11 and 12 of the ring-shaped arc tubes 1 and 2 is 13 mm, and both ends of the ring-shaped arc tube 2 located inside. The center-to-center distance l'between the parts is 18 mm.
When this ring-shaped fluorescent lamp was lit with a lamp input of 25 W using an inverter circuit of 50 kHz, the color temperature was 3
A luminous flux value as high as 1490 lm was obtained with an emission color of 000 Kelvin. When the temperatures of the ring-shaped arc tubes 1 and 2 were measured, the coldest spots were formed at the other end portions 11 and 12, and the temperature of the coldest spots was 25 W at the time of lighting (room temperature 25
(° C) was 45 ° C, which is equivalent to the optimum mercury vapor pressure at which the maximum luminous flux value was obtained. Furthermore, as a result of various studies, the outer diameters of the ring-shaped arc tubes 1 and 2 are set to d, and the end portions of the bridge joint portion 5 are connected to the other ends 11 and 1 of the ring-shaped arc tubes 1 and 2.
2 the distance L to the center of the end face is 0.5d ≦ L ≦ 1.3
By setting in the range of d, the temperature of the coldest spot is
It was possible to keep the mercury vapor pressure in the arc tube in an optimum region, and it was possible to easily obtain the maximum value of the luminous flux of the lamp.

<Second Embodiment> In the present embodiment, the above-mentioned first embodiment is used.
The ring-shaped fluorescent lamp in which the base is attached to the ring-shaped fluorescent lamp of the embodiment will be described.

First, as shown in FIG. 3, the ring-shaped arc tube 1,
A ring-shaped fluorescent lamp was manufactured by surrounding both ends of No. 2 with a base 28 similar to the conventional one, and various characteristics of the lamp were measured. As a result, such a lamp has a luminous flux value of 1490 lm to 1 as compared with a bare lamp having no base.
It was found to be significantly reduced to 260 lm. The reason why the luminous flux value is remarkably lowered is that the temperature of the coldest spot, that is, the mercury vapor pressure in the tube rises excessively from the optimum region.

Based on the above results, the inventors of the present invention, based on the above results, use the base 29 to make one end (electrodes 3, 4) of the ring-shaped arc tubes 1, 2.
Side) and the other ends (the coldest spots) 11 and 12 are separated from the base 29 to expose the ring-shaped fluorescent lamp (FIG. 4) to the outside air, and one ends of the ring-shaped arc tubes 1 and 2 ( Electrodes 3, 4
(Side) and the other ends 11 and 12 have a vent 3 having a vent 10.
A ring-shaped fluorescent lamp (FIG. 5) which was surrounded by 0 and whose other ends 11 and 12 were in contact with the outside air by the vent hole 10 of the base 30 was manufactured. The luminous flux values of these ring-shaped fluorescent lamps were 1575 lm as shown in FIG. 4 and 1520 lm as shown in FIG. 5, which were very close to the luminous flux values of the bare lamp without the base. The reason why the decrease in the lamp luminous flux is suppressed is that the heat of the electrodes 3 and 4 is not transferred to the other ends 11 and 12 and the temperature of the coldest spot is not excessively increased from the optimum region. .

<Third Embodiment> In this embodiment, a ring type fluorescent lamp having a rated power of 60 W will be described. The ring-shaped fluorescent lamp of this embodiment basically has the same structure as that of the first embodiment (FIGS. 1 and 2). Then, in this ring-shaped fluorescent lamp, as in the case of FIG. 4, one end of the ring-shaped arc tubes 1 and 2 (on the side of the electrodes 3 and 4) is surrounded by the base 29,
The other ends (the coldest spots) 11 and 12 are separated from the mouthpiece 29 and are in a state of being in contact with the outside air.

The respective dimensions of the ring-shaped fluorescent lamp of this embodiment are as follows: the ring-shaped arc tubes 1 and 2 have an outer diameter of 20 mm, the outer ring-shaped arc tube 1 has an outer diameter of 240 mm and an inner ring-shaped arc tube. The ring inner diameter of 2 is 155 mm, and the distance L from the end of the bridge joint portion 5 to the center of the end faces of the other end portions 11 and 12 is 1
9 mm, center-to-center distance l of both ends of the ring-shaped arc tube 2 is 22 m
m. When this lamp was lit with a lamp input of 60 W using an inverter circuit of 50 kHz, 4390
A high luminous flux value of lm was obtained.

As the base of the ring-shaped fluorescent lamp of this embodiment,
Using a conventional base 28 as shown in FIG.
Further studies were made on the structure in which both ends of the ring-shaped arc tubes 1 and 2 are surrounded by. As a result, even when the entire ends of the ring-shaped arc tubes 1 and 2 are surrounded by the bases, one end (electrodes 3 and 4 side) and the other end of the ring-shaped arc tubes 1 and 2 as shown in FIG. If the base 31 provided with the heat-shielding partition wall 16 that is a heat-shielding member that thermally shields the portions 11 and 12 is used, the coldest spot (from the one end (electrodes 3 and 4 side) of the ring-shaped arc tubes 1 and 2 ( It is possible to prevent the temperature of the coldest spot from rising excessively from the optimum region by suppressing the transfer of heat to the other end portions 11 and 12), so that the luminous flux of the lamp is prevented from decreasing. You can Given the specific numbers,
The light flux value when the base 28 of FIG. 3 was used was 1260 lm, but the light flux value when the base 31 provided with the heat shielding partition 16 was used was 1420 lm. Further, it has been found that the similar heat shielding effect can be obtained also for the base 30 provided with the vent hole 10 of FIG. Given the specific numbers,
The luminous flux value was 1520 lm as described above when the base 30 having only the vent holes 10 was used, but the luminous flux value was 1560 lm (40
lm improvement).

<Fourth Embodiment> FIG. 7 is a front view showing an example of a structure around a bridge joint portion of a fourth embodiment of a ring type fluorescent lamp according to the present invention, and FIG. 8 is a ring type fluorescent lamp according to the present invention. It is a front view which shows the other example of the structure of the bridge junction part periphery of the 4th Example of this.

In this embodiment, as shown in FIGS.
A ring-shaped fluorescent lamp is produced using the bases 32 and 33 that expose one of the other ends 11 and 12 of the ring-shaped arc tubes 1 and 2 to the outside, and the other end 11 (or 12) of the exposed one is The coldest spot was formed. Also in this case, the base 29 of FIG.
A luminous flux value similar to that obtained by using was obtained. In particular, since it is possible to obtain a high luminous flux value by reducing the non-luminous area at the end of the arc tube, as shown in FIG. 7, the coldest spot is provided at the other end 11 of the annular arc tube 1 located outside. Is preferably provided.

<Fifth Embodiment> FIG. 9 is a partially cutaway front view showing an example of a structure around a bridge joint portion of a fifth embodiment of a ring-shaped fluorescent lamp according to the present invention. As shown in FIG. 9, bending holding portions 20 are provided on the outer wall surfaces of both ends of the ring-shaped arc tubes 1 and 2. Further, at least the other end portions 11 and 12 on the non-electrode side of the ring-shaped arc tubes 1 and 2, a groove portion 19 is provided on the inner wall surface on the tip side of the bending holding portion 20. Also, one end of the circular arc tubes 1 and 2 (on the side of the electrodes 3 and 4)
Is surrounded by the base 34, and the other ends 11, 12
Is separated from the cap 34 and is in a state of being exposed to the outside air. According to this configuration, since the bending holding portion 20 of the ring-shaped arc tubes 1 and 2 can be firmly held in the lamp manufacturing process, the bending accuracy of the ring-shaped arc tubes 1 and 2 can be improved. Further, according to this configuration, the coldest spot is formed in the groove portion 19, and the temperature can be maintained at the optimum value.

As shown in FIG. 10, if the other end portions 11 and 12 on the non-electrode side are sealed with a stem similar to the end portion on the electrode side, compared to the case of the end portion structure as shown in FIG. As a result, the strength of the other end portions 11 and 12 on the non-electrode side is improved. In the case of the end portion structure shown in FIG. 9, since the end portion is formed by melting a part of the arc tube, the non-electrode side other end portions 11 and 12 have a thin wall thickness particularly in the arc tube having a large tube diameter. Will end up. On the other hand, in the case of sealing with the stem, the end can be firmly sealed, and inconveniences such as bending of the arc tube and cracking of the end after completion of the lamp can be eliminated. . Further, in the case of sealing with the stem, the manufacturing is relatively easy as compared with the case of the end structure shown in FIG. 9, and the manufacturing can be performed using the conventional manufacturing equipment.

Further, in the present embodiment, the base 34 which surrounds only one end of the ring-shaped arc tubes 1 and 2 is used as the base, but the base is not necessarily limited to the base having this structure, and at least non-base. It suffices that the base structure is such that the other end portions 11 and 12 on the electrode side are exposed to the outside air.

<Sixth Embodiment> FIG. 11 is a partially cutaway front view showing a structure around a bridge joint portion of a sixth embodiment of a ring-shaped fluorescent lamp according to the present invention. As shown in FIG. 11, the base 35 includes one end portion of the ring-shaped arc tubes 1 and 2 (electrode 3,
4 side) and the coldest spots of the other end portions 11 and 12 on the non-electrode side. Further, the base 35 has a vent 10 for exposing the coldest spot to the outside air, and ring-shaped arc tubes 1, 2.
End portions (electrodes 3, 4 side) and non-electrode side other end portions 11, 12 of
There is provided a heat-shielding partition wall 16 that is a heat-shielding member that thermally shields and. According to this configuration, the effect of preventing the temperature rise of the vent hole 10 and the heat shielding partition wall 16 is combined, and it is possible to reliably prevent the temperature of the coldest spot from excessively rising from the optimum region. It is possible to reliably prevent the lamp luminous flux from decreasing.

<Seventh Embodiment> FIG. 12 is a partially cutaway front view showing an example of a structure around a bridge joint portion of a seventh embodiment of a ring-shaped fluorescent lamp according to the present invention. As shown in FIG. 12, bending holding portions 20 are provided on the outer wall surfaces of both ends of the ring-shaped arc tubes 1 and 2. In addition, the ring-shaped arc tube 1,
At least at the other end portions 11 and 12 on the non-electrode side of 2, a groove portion 19 is provided on the inner wall surface on the tip side of the bending holding portion 20. Since the other structure is the same as that of the sixth embodiment (FIG. 11), the same reference numerals are given to the same members and the description thereof will be omitted. According to this structure, the coldest spot is formed in the groove portion 19 and the temperature thereof is maintained at the optimum value. Therefore, the temperature rise of the coldest spot is more surely increased as compared with the case of the sixth embodiment. Can be prevented. Further, according to this configuration, since the bending holding portions 20 of the ring-shaped arc tubes 1 and 2 can be firmly held in the lamp manufacturing process,
The bending accuracy of the ring-shaped arc tubes 1 and 2 can be improved.

As shown in FIG. 13, if the other end portions 11 and 12 on the non-electrode side are sealed with a stem similar to the end portion on the electrode side, compared to the case of the end portion structure as shown in FIG. As a result, 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. 12, a part of the arc tube is melted to form the end part. Therefore, in the arc tube having a large tube diameter, the thicknesses of the other end portions 11 and 12 on the non-electrode side are thin. Will end up. On the other hand, in the case of sealing with the stem, the end can be firmly sealed, and inconveniences such as bending of the arc tube and cracking of the end after completion of the lamp can be eliminated. . Further, in the case of sealing with the stem, the manufacturing is relatively easy as compared with the case of the end structure shown in FIG.
It can be manufactured using conventional manufacturing equipment.

[0042]

As described above, the ring-shaped fluorescent lamp of the present invention is designed so that the coldest spot is in communication with the outside air. Therefore, the temperature of the coldest spot, that is, the mercury vapor pressure in the tube is It is kept in the optimum region and a high lamp luminous flux value is obtained. In addition, a compact, high-efficiency, high-output ring-shaped fluorescent lamp will be realized.

[Brief description of 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 joint portion of the annular fluorescent lamp of FIG.

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 second and third embodiments of the present invention.

FIG. 4 is a front view showing an example of the structure around the bridge joint portion of the second embodiment of the ring-shaped fluorescent lamp according to the present invention.

FIG. 5 is a front view showing another example of the structure around the bridge joint portion of the second embodiment of the ring-shaped fluorescent lamp according to the present invention.

FIG. 6 is a partially cutaway front view showing a structure around a bridge joint portion of a ring type fluorescent lamp according to a third embodiment of the present invention.

FIG. 7 is a front view showing an example of a structure around a bridge joint portion of a ring-shaped fluorescent lamp according to a fourth embodiment of the present invention.

FIG. 8 is a front view showing another example of the structure around the bridge joint portion of the fourth embodiment of the ring-shaped fluorescent lamp according to the present invention.

FIG. 9 is a partially cutaway front view showing an example of a structure around a bridge joint portion of a ring type fluorescent lamp according to a fifth embodiment of the present invention.

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

FIG. 11 is a partially cutaway front view showing a structure around a bridge joint portion of a ring type fluorescent lamp according to a sixth embodiment of the present invention.

FIG. 12 is a partially cutaway front view showing an example of a structure around a bridge joint portion of a ring type fluorescent lamp according to a seventh embodiment of the present invention.

FIG. 13 is a partially cutaway front view showing another example of the structure around the bridge joint portion of the seventh embodiment of the ring-shaped fluorescent lamp according to the present invention.

[Explanation of symbols]

1, 2 Ring-shaped arc tube 3, 4 Electrode 5 Bridge junction 6 Phosphor 28, 29, 30, 31, 32, 33, 34, 35 Base 10 Vent 11, 12 (non-electrode side) other end 16 Heat shield Partition wall 19 groove portion 20 bending holding portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masatsugu Sangen 1 1-1 Sachimachi Takatsuki, Osaka Prefecture Matsushita Electronics Industrial Co., Ltd.

Claims (12)

[Claims] 1. 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, and a bridge joint portion is provided in the vicinity of the other ends of the plurality of ring-shaped arc tubes. A ring-shaped fluorescent lamp having a discharge path formed inside and a coldest spot formed at the other end, the bridge being joined from the other end to the other end. Is L (mm) and the outer diameter of the ring-shaped arc tube is d (mm), 0.5d ≦ L ≦ 1.
A ring-shaped fluorescent lamp which satisfies the relationship of 3d. 2. 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, and a bridge joint portion is provided in the vicinity of the other ends of the plurality of ring-shaped arc tubes. Are joined together to form one discharge path inside, a coldest spot is formed at the other end, and a base surrounding at least one of the one end and the other end is formed. An annular fluorescent lamp provided, wherein the coldest spot is exposed to the outside air. 3. 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, and the vicinity of the other ends of the plurality of ring-shaped arc tubes is a bridge joint. Are joined together to form one discharge path inside, a coldest spot is formed at the other end, and a base surrounding at least one of the one end and the other end is formed. A ring-shaped fluorescent lamp provided with the base, wherein the base is provided with a heat shield member for heat-shielding the one end and the other end of the ring-shaped arc tube. 4. The ring-shaped fluorescent lamp according to claim 1, wherein a plurality of ring-shaped arc tubes are arranged on the same plane. 5. The ring-shaped fluorescent lamp according to claim 1, wherein the curved holding portions are provided on the outer wall surfaces of both ends of the ring-shaped arc tube. 6. The ring-shaped fluorescent lamp according to claim 5, wherein a groove is provided on an inner wall surface of the ring-shaped arc tube at least at the other end of the ring-shaped arc tube on the tip side of the holding portion for bending. 7. The ring-shaped fluorescent lamp according to claim 1, wherein the other end of the ring-shaped arc tube on the non-electrode side is sealed by a stem. 8. When the distance from the end of the bridge joint to the center of the end face of the other end is L (mm) and the outer diameter of the ring-shaped arc tube is d (mm), 0.5d ≦ L ≦ The ring fluorescent lamp according to claim 2, wherein the relationship of 1.3d is satisfied. 9. The ring-shaped fluorescent lamp according to claim 2, wherein the base is provided apart from the coldest spot of the other end. 10. A mouthpiece is provided so as to surround one end portion and the coldest spot portion of the other end portion, and the mouthpiece is provided with a vent hole for exposing the coldest spot portion to the outside air. Item 4. The ring-shaped fluorescent lamp according to Item 2 or 3. 11. The ring-shaped fluorescent lamp according to claim 2, wherein the coldest spot is formed on the ring-shaped arc tube located outside of the plurality of ring-shaped arc tubes. 12. A plurality of ring-shaped light emitting tubes, each having an electrode at one end and a closed portion sealed by a stem at the other end, are arranged concentrically on the same plane, and the plurality of ring-shaped light-emitting tubes are provided. A ring-shaped fluorescent lamp in which the vicinity of the other end of the tube is joined by a bridge joint, and a single discharge path is formed inside, and a coldest spot is formed at the other end.
The distance from the end of the bridge joint to the center of the end face of the other end is L (mm), and the outer diameter of the ring-shaped arc tube is d (m).
m), the relationship of 0.5d ≦ L ≦ 1.3d is satisfied, and a die surrounding the one end and the other end is provided, and the die has the coldest spot location. A ring-shaped fluorescent lamp, which is provided with a vent for allowing the air to come into contact with the outside air, and a heat-shielding member for thermally shielding the one end and the other end of the ring-shaped arc tube.