JP2001023568A - Circular fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent lamp expected for an improvement effect of brightness and luminous efficiency, and capable of providing fixed productivity, although the diameter of a circular glass tube is reduced. SOLUTION: This circular fluorescent lamp is made up of a circular glass tube 11 having electrodes 10, 10 disposed in both end parts thereof, and mercury and inert gas sealed therein. A recessed part 13 comprising a helical groove 13a partly recessed toward the inside of the glass tube is formed in a glass-tube outer circumferential surface including the middle part and distanced from both the end parts of the circular glass tube 11.

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, and more particularly to a ring-type fluorescent lamp for exclusive use in high-frequency applications in which the diameter of a ring-shaped glass tube in which mercury and an inert gas are sealed is reduced to about 16 mm. .

[0002]

2. Description of the Related Art In general, a ring-shaped fluorescent lamp is provided with electrodes on both ends of a straight glass tube having a light-emitting layer on the inner surface and having a diameter of about 29 mm, and the glass tube is heated and softened to form a ring. The ring-shaped glass tube is bent, and a predetermined amount of mercury and an inert gas are sealed in the inner space of the ring-shaped glass tube. The lighting operation is performed by applying a predetermined voltage between the electrodes.

For example, a 40 W type three-wavelength ring type fluorescent lamp can obtain a brightness (total luminous flux) of about 3070 (lm), and a 32 W type can obtain a brightness of about 2360 (lm). A luminous efficiency of about (lm / W) is obtained, and it is widely applied to household lighting equipment.

Recently, it has been required to further improve the brightness and luminous efficiency of these ring-shaped fluorescent lamps. A ring-shaped fluorescent lamp for exclusive use in high frequency use, in which the diameter of the ring-shaped glass tube is reduced to about 16 mm. Lamps have been proposed and put into practical use.

According to the ring-shaped fluorescent lamp exclusively used for high frequency, the current density can be set high and the efficiency can be increased by reducing the diameter of the ring-shaped glass tube. For example, a 34 W type (comparable to the conventional 40 W type) can be used. 3270 (l)
m), a brightness of 2510 (lm) is obtained with a 27 W type (corresponding to a conventional 32 W type), and the luminous efficiency is greatly improved to 92 to 96 (lm / W). .

In general, it is known that the brightness at the time of lighting of a ring-shaped fluorescent lamp depends on the mercury vapor pressure in a glass tube, and the mercury vapor pressure is regulated by the coldest point temperature, which is the lowest temperature in the glass tube. . In addition, it is also known that when the mercury vapor pressure is approximately 6 μmmHg, the light is lit most efficiently and brightly, and the lighting efficiency decreases even if the mercury vapor pressure becomes higher or lower than the optimum value. This type of ring-shaped fluorescent lamp is designed so that the mercury vapor pressure in the glass tube is about 6 μmmHg when turned on.
This optimum mercury vapor pressure is obtained when the coldest point temperature in the glass tube is approximately 40 ° C.

However, in the above-described ring-type fluorescent lamp dedicated to high-frequency operation, the current density is increased by reducing the diameter of the glass tube, so that the coldest point temperature in the glass tube at the time of operation can obtain the optimum mercury vapor pressure. Higher than the required 40 ° C., and the brightness and the luminous efficiency are impaired accordingly.

[0008] In particular, when this ring-shaped fluorescent lamp is applied to a closed-type lighting fixture or the like which is hermetically sealed by a cover or the like, the temperature inside the fixture becomes even higher, so that the cold spot temperature of the ring-shaped fluorescent lamp is also lowered. Higher, more bright,
The lighting efficiency is impaired.

[0009]

Accordingly, conventionally, in order to solve such a problem, a mercury amalgam is disposed inside a ring-shaped glass tube, or an optimum cold spot temperature for a part of the ring-shaped glass tube is set. Various solutions have been attempted, such as forming a deformed portion to secure the height, or increasing the height of the electrode from the end of the annular glass tube.

In the first method, for example, indium (Cd), cadmium (Cd), thallium (T
l), antimony (Sb), gold (Au), tin (Sn),
An amalgam-forming metal such as zinc (Zn) is fixed, and a mercury amalgam is formed by the amalgam-forming metal and mercury. In-Hg amalgam is recommended.

According to this method, the mercury vapor pressure in the amalgam state is lower than the mercury vapor pressure in the pure mercury state. Therefore, if the mercury amalgam, which is the coolest part of the annular glass tube, is installed at an appropriate temperature. Even if the temperature becomes higher than the coldest point temperature, it becomes possible to maintain an appropriate mercury vapor pressure. For this reason, it is possible to sufficiently improve the brightness and the luminous efficiency.

However, if strong vibration or impact is applied to the ring-shaped glass tube during production, transportation, or the like, the installation position of the mercury amalgam may shift. Especially when moving to a part close to the electrode, the temperature of the mercury amalgam at the time of lighting becomes higher than when it is installed at the stem end, so the mercury vapor pressure also increases, and This causes a problem that the brightness and the luminous efficiency are lower than the design values.

In the early stage of lighting, the temperature of the mercury amalgam is low, so that the mercury vapor pressure inside the annular glass tube is low.
Sufficient brightness cannot be obtained. For example, when about 5 to 10 minutes have elapsed after lighting, the temperature of the ring-shaped glass tube also rises due to discharge or the like, and the ring-shaped glass tube becomes saturated, the temperature of the mercury amalgam also reaches a predetermined value, and the mercury vapor pressure reaches an optimum. However, the fact that sufficient brightness cannot be obtained at the beginning of lighting causes a problem that the original lighting function cannot be satisfied.

The second method is, for example, as shown in FIG.
One in which a deformed portion (glass projection 2) for securing an optimum cold spot temperature is formed integrally at one central portion of the annular glass tube 1 (a portion farthest from the electrodes 3 and 3 at both ends). It is. Specifically, before or after the bending of the glass tube, the central portion of the annular glass tube 1 is heated and softened, and in this state, the internal pressure of the glass tube is made slightly higher than the atmospheric pressure to form the glass projection 2. Is done.

According to this method, the glass projection 2 is sufficiently separated from the electrodes 3 and 3 to reduce the thermal influence, and the current density in this portion is sufficiently lower than that in the other portions. In some cases, the coolest part is formed. Therefore, the mercury vapor pressure in the ring-shaped glass tube is controlled to a vapor pressure determined by the temperature of the glass projection 2, so that brightness and luminous efficiency are improved.

However, since the ring-shaped fluorescent lamp has the glass projection 2 formed at the center of the ring-shaped glass tube 1, it is easily damaged not only during manufacturing but also during handling due to external impact. There's a problem.

The third method is, for example, as shown in FIG.
The stem mount 7a is taller so that the height of one electrode 6a from the end of the annular glass tube 5 is higher. The other electrode 6b is mounted on a normal height stem mount 7b.

According to this method, the end 8 of the ring-shaped glass tube 5 on the stem mount 7a side becomes the coldest part in the ring-shaped glass tube 5 because the thermal influence from the electrode 6a is reduced. Therefore, the mercury vapor pressure in the ring-shaped glass tube is controlled to a vapor pressure determined by the temperature of the end portion 8, thereby improving brightness and luminous efficiency.

However, in this ring-shaped fluorescent lamp,
The length of the discharge path between the pair of electrodes 6a and 6b is shortened by the high mounting by the stem mount 7a as compared with the ring-shaped fluorescent lamp according to the first and second methods, and the brightness is substantially reduced. There's a problem.

In addition, the electrode 6a comes into contact with or abnormally approaches the inner surface of the bent annular glass tube 5 during the bending operation of the glass tube due to the high mounting by the stem mount 7a. . There is also a problem that the ring-shaped glass tube 5 may be damaged by the thermal influence from the electrode 6a during lighting. Such a problem can be theoretically solved by deforming the stem mount 7a in advance in accordance with the bending direction of the ring-shaped glass tube 5, but in reality, the production of such a stem mount 7a is possible. Is extremely difficult, and when bending a straight glass tube, it is extremely difficult to set the bending direction of the glass tube so that the deformation direction of the stem mount 7a matches the bending direction of the glass tube. There is a new problem that it is difficult to apply to a mass production process.

Therefore, an object of the present invention is to provide a ring-shaped fluorescent lamp which can be expected to improve brightness and luminous efficiency even if the diameter of the ring-shaped glass tube is reduced, and which can obtain predetermined productivity. is there.

[0022]

SUMMARY OF THE INVENTION Accordingly, in order to achieve the above-mentioned object, the present invention provides an annular fluorescent lamp having an annular glass tube in which electrodes are arranged at both ends and mercury and an inert gas are sealed. A concave portion which is partially recessed toward the inside of the glass tube is formed on an outer peripheral surface of the glass tube including a central portion away from both ends of the ring-shaped glass tube.

Here, a partially formed concave portion is formed in the outer peripheral surface of the ring-shaped glass tube so as to be recessed toward the inside of the glass tube, and the cross-sectional area in the glass tube having the concave portion is the same as that of the concave portion. It becomes smaller than the cross-sectional area in the glass tube without the recess, and the coldest part is easily formed at the boundary between the inner surface of the glass tube with the recess and the inner surface of the glass tube without the recess. In particular, the coldest spot is actively formed at the boundary of the concave portion in the center away from the electrode of the annular glass tube, and the brightness and light emission are controlled by the mercury vapor pressure determined by the temperature of the coldest portion. Efficiency is improved. The shape and number of the concave portions formed in such an annular glass tube are not specified, but the following claim 2 is practically effective.

The invention according to claim 2 of the present invention is characterized in that the recess is a groove formed in a circumferential direction including a spiral direction of the outer periphery of the glass tube. The concave portion here is formed by a spiral groove, a peripheral groove surrounding the outer periphery of the glass tube, a plurality of the peripheral grooves, a combination of the peripheral groove and the spiral groove, and the like.

Further, according to the invention of claim 3 of the present invention, the annular glass tube has a tube diameter of 20 mm or less, preferably 1 mm or less.
It is characterized in that it is set to about 6 mm. When the above-described concave portion is formed in the ring-shaped glass tube of the ring-shaped fluorescent lamp of a high-frequency lighting type having a tube diameter of 20 mm or less, brightness and luminous efficiency can be improved by the cold spot forming effect of the concave portion.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, various embodiments of the present invention will be described in order with reference to FIGS. In the figure, the same or corresponding portions of the embodiment are denoted by the same reference numerals to avoid duplication of description.

The ring-shaped fluorescent lamp shown in FIGS. 1A and 1B has electrodes 10 at both ends and a ring-shaped glass tube 11 in which mercury and an inert gas are sealed in an internal space.
A concave portion 13 is partially formed on an outer peripheral surface of the ring-shaped glass tube 11, and bases 12 are attached to both ends of an annular glass tube 11. In particular, the concave portion 13 of the ring-shaped glass tube 11 has a spiral groove 13a formed over almost the entire length of the glass tube 11.
The annular glass tube 11 is formed so as to be recessed from the outer surface toward the inner surface.

The spiral groove 13a is formed, for example, as follows. First, a straight glass tube (not shown) is heated and softened while rotating. In this state, a rod-shaped mold is pressed against the straight tube glass tube from a certain direction, and the outer surface of the straight tube glass tube is depressed toward the inner surface by the mold. The mold is relatively moved in the axial direction of the rotating straight tube glass tube, and grooves are sequentially formed in a spiral shape on the outer peripheral surface of the straight tube glass tube. Hereinafter, a ring-shaped fluorescent lamp is manufactured by an ordinary method.

FIG. 1B shows a cross section of the spiral groove 13a formed as described above. The cross-sectional area in the annular glass tube 11 is larger at the portion Q without the spiral groove 13a than at the portion P with the spiral groove 13a. Therefore, the spiral groove 13
The current density of the portion Q without the a is the portion P with the spiral groove 13a.
Is formed at the boundary portion E between the inner peripheral surface of the glass tube 11 and the spiral groove 13a.
Also, the central portion of the ring-shaped glass tube 11 distant from the electrodes 10, 10 is less likely to be thermally affected by the electrodes 10, 10,
The coldest part is likely to be formed at the boundary E of the spiral groove 13a existing in the central part. Therefore, brightness and luminous efficiency can be improved even if the diameter of the annular glass tube 11 is reduced.

For example, when the diameter of the annular glass tube 11 is 16 mm
When the spiral groove 13a is formed at a depth of about 3 to 5 mm, the mercury vapor pressure in the glass tube is slightly higher than the optimum value, but is higher than that without the spiral groove 13a. The improvement of the luminous efficiency was confirmed. The effect of improving the brightness and the like by the spiral groove 13a is more effective as the diameter of the annular glass tube 11 is reduced to 20 mm or less.
Can be further reduced in diameter.

Further, since the spiral groove 13a is formed so as to be recessed from the outer peripheral surface of the annular glass tube 11 toward the inner surface, the spiral groove 13a is damaged even when subjected to vibration, impact, or the like during manufacture or use. For example, it is possible to suppress a decrease in the manufacturing yield of the ring-shaped fluorescent lamp, and it is possible to perform handling operations such as packaging of the ring-shaped fluorescent lamp at the same level as a normal ring-shaped fluorescent lamp.

The spiral groove 13a may be formed only at the center of the ring-shaped glass tube 11. In particular, as shown in FIG. 1A, the spiral groove 1 extends over almost the entire length of the annular glass tube 11.
By forming the spiral groove 13a, the spiral groove 13a can be used as an aesthetic point on the appearance of the ring-shaped fluorescent lamp, and the merchantability of the ring-shaped fluorescent lamp can be improved.

The ring-shaped fluorescent lamps shown in FIGS.
The concave portion 13 is formed only in the center portion of the annular glass tube 11 in the circumferential direction.
Is formed. The concave portion 13 is a peripheral groove 13b that goes around the outer periphery of the central portion of the annular glass tube 11. The circumferential groove 13b is one or several, and two grooves are formed at two places separated from each other in FIG. Such a circumferential groove 1
The formation of 3b is performed in the state of the straight tube glass tube in the manner of forming the spiral groove shown in FIG. 1 or by a bending mold when the straight tube glass tube is bent into an annular shape. It is done by doing.

By forming the peripheral groove 13b at the center of the annular glass tube 11, the coldest portion is formed at the boundary E between the inner surface of the central portion of the annular glass tube 11 and the peripheral groove 13b. The same effect as the example can be obtained. Further, the circumferential groove 13b can also be a beauty point on the appearance of the ring-shaped glass tube 11.

It should be noted that the present invention is not limited to the above-described embodiment, and the concave portion can be applied to a normal ring-shaped fluorescent lamp. The diameter of the ring-shaped glass tube is 20 mm
If it is below, a size other than 16 mm can be selected.

[0036]

As described above, according to the present invention, the concave portion formed on the outer peripheral surface of the ring-shaped glass tube is recessed toward the inner surface of the ring-shaped glass tube, and the boundary with the bulging portion on the inner surface. Since the coldest part is easily formed in the portion, the brightness and the luminous efficiency can be improved even if the diameter of the annular glass tube is reduced. In particular, a characteristic effect can be expected when applied to a ring-shaped fluorescent lamp of a lighting type dedicated to high frequency in which the diameter of the ring-shaped glass tube is set to 20 mm or less.

If the shape and number of the concave portions formed on the outer peripheral surface of the ring-shaped glass tube are designed aesthetically, the appearance characteristics of the ring-shaped fluorescent lamp can be improved, and the commercialization can be expected to be improved.

[Brief description of the drawings]

FIG. 1A is a front view of a ring-shaped fluorescent lamp according to a first embodiment, and FIG. 1B is a partially enlarged cross-sectional view of the ring-shaped glass tube of FIG.

FIG. 2A is a front view of a ring-shaped fluorescent lamp showing a second embodiment, and FIG. 2B is a partially enlarged cross-sectional view of the ring-shaped glass tube of FIG.

FIG. 3 is a lamp configuration diagram showing an outline of a conventional ring-shaped fluorescent lamp.

FIG. 4 is a lamp configuration diagram showing an outline of another conventional ring-shaped fluorescent lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Electrode 11 Ring-shaped glass tube 13 Recess 13a Spiral groove 13b Peripheral groove

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Ken Maejima 1-44 Shiromi, Chuo-ku, Osaka-shi, Japan NEC Home Electronics Co., Ltd. F-term (reference) 5C043 AA02 AA12 CC09 CD10 DD01 EA05 EA06

Claims (3)

[Claims] 1. An annular fluorescent lamp having an annular glass tube filled with mercury and an inert gas by disposing electrodes at both ends, wherein the outer peripheral surface of the glass tube includes a central portion separated from both ends of the annular glass tube. A ring-shaped fluorescent lamp, wherein a concave portion which is partially recessed toward the inside of the glass tube is formed. 2. The ring-shaped fluorescent lamp according to claim 1, wherein the recess is a groove formed in a circumferential direction including a spiral direction of the outer periphery of the glass tube. 3. The ring-shaped fluorescent lamp according to claim 1, wherein the diameter of the ring-shaped glass tube is set to 20 mm or less, preferably about 16 mm.