JP2013125714A - Fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent lamp including three or more conventional annular luminous tubes having different annular diameters and arranged substantially conically in a substantially same plane, in which the total luminous flux and luminous efficiency of the lamp are improved when the lamp is attached to a hermetically sealed fixture, by lowering the coldest point without changing the maximum outer diameter.SOLUTION: In the cross-sectional shape of a tube at a part of the bridge joint of an annular luminous tube on the side opposite from a discharge path, the length (a) perpendicular to the concentric surface of a ring is made longer than a length b parallel with the surface of the concentric circle of the ring. Since the coldest point can be located at the lowermost part of the tube end near the bridge joint, the temperature can be lowered below that at the outermost part of the tube end near the bridge joint. In such an atmosphere that the ambient temperature increases when the lamp is attached to a hermetically sealed fixture, the lamp can be brought close to a temperature where the total luminous flux is maximized, and can be lighted in such a state that the luminous efficiency is high in the fixture.

Description

  The present invention relates to a fluorescent lamp.

  There exists a thing shown in patent document 1 as a conventional multi-ring fluorescent lamp. For example, FIG. 1 of Patent Document 1 shows a fluorescent lamp provided with a double-ring shaped arc tube. In this fluorescent lamp, two arc tubes are connected by a bridge junction, and one discharge path is formed along the path from the tube end electrode of one arc tube to the tube end electrode of the other arc tube. .

  Since this fluorescent lamp arc tube has two ring arc tubes connected to form one discharge path, when a fluorescent lamp is created with the same maximum outer diameter, one ring arc tube has one discharge. The discharge path can be made longer than the fluorescent lamp forming the path. By making the discharge path of the arc tube longer and increasing the emission area, it is possible to create a lamp with a large total luminous flux and improved luminous efficiency.

Japanese Patent No. 2776840

  In the multi-ring fluorescent lamp as shown in Patent Document 1, the tube end near the bridge junction is the coldest point, and the metal mercury in the fluorescent lamp is gathered at this coldest point. Since the luminous efficiency of the fluorescent lamp depends on the temperature of the coldest spot, it is necessary to keep the temperature of the coldest spot low in order to increase the luminous efficiency. However, when the fluorescent lamp of Patent Document 1 is mounted in a sealed appliance, the coldest spot of the fluorescent lamp is heated under the influence of the atmosphere heated by the fluorescent lamp, resulting in a problem that the luminous efficiency is lowered.

  In view of the above, an object of the present invention is to provide a fluorescent lamp with high luminous efficiency without increasing the thickness and maximum outer diameter of the fluorescent lamp.

  The problems include a plurality of ring-shaped arc tubes having different ring diameters, a connecting portion connecting the plurality of ring-shaped arc tubes, an electrode provided at a tube end of the outermost ring-shaped arc tube through the connection portion, and an outermost portion. A fluorescent lamp having a discharge path connecting electrodes provided at the tube end of the inner ring-shaped arc tube, the tube end of the outermost ring-shaped arc tube without the electrode Is provided at a position away from the discharge path, and can be solved by a fluorescent lamp having an elliptical cross section at the tube end not provided with the electrode.

  According to the present invention, it is possible to light a fluorescent lamp with high luminous efficiency even in a sealed appliance.

The top view of the arc tube of the fluorescent lamp of one Example. 1 is a cross-sectional plan view of an arc tube according to an embodiment. The vertical sectional view of the arc tube of one example. The figure which shows the relationship between the coldest spot temperature of the fluorescent lamp of one Example, and a total luminous flux. The figure which shows the cross-sectional shape of the fluorescent lamp of one Example, and the relationship of the coldest point temperature.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an annular fluorescent lamp 40 of this embodiment. As shown here, the fluorescent lamp 40 includes an arc tube 41, a base 43, and an adhesive 44. The arc tube 41 includes three concentric ring-shaped arc tubes 41a, 41b and 41c, a bridge junction portion 42a coupling the ring-shaped arc tubes 41a and 41b, and a bridge junction portion 42b coupling the ring-shaped arc tubes 41b and 41c. It is composed of Furthermore, the tube ends of the annular arc tubes 41a, 41b, 41c are surrounded by a base 43, and a plurality of adhesives 44 are provided between the annular fluorescent tubes, so that a substantially constant gap is provided between the annular arc tubes. S ₁ and S ₂ are provided.

In this embodiment, the gaps S ₁ and S ₂ are in the range of 3.0 to 15.0 mm. The gap was set to 3.0 mm or more because each circular arc tube can be arranged in the same plane even if the circular accuracy is somewhat bad, so that high manufacturing accuracy is unnecessary and manufacturing cost can be suppressed. Since each annular arc tube serving as a heat source can be dispersedly arranged, it is possible to suppress an increase in the ambient temperature particularly when the fluorescent lamp 40 is attached to a sealed type appliance, and the temperature increase at the coldest spot of the arc tube 41, that is, the luminous efficiency. It is because the fall of can be suppressed. In addition, the gap is set to 15.0 mm or less by narrowing the gap that becomes a dark part and reducing bright and dark spots, and particularly when the fluorescent lamp 40 is mounted on a sealed type appliance, it is hermetically sealed to suppress bright and dark spots. This is because there is no need to increase the light reflectance and light diffusivity of the cover member of the mold tool, and the illuminance can be easily kept high.

  FIG. 2 is a plan sectional view of the arc tube 41. An electrode 65a having a tungsten filament and a pair of lead wires for power feeding is hermetically sealed at one end of the outer annular arc tube 41a, and the same is applied to one end of the inner annular arc tube 41c. The electrode 65b is hermetically sealed. The arc tube 41 emits light by discharging to one discharge path connecting the electrode 65a and the electrode 65b via the bridge joint portions 42a and 42b. In this embodiment, the bridge joint portions 42a and 42b are provided at a position of about 30 mm from the tube end portion of each annular arc tube. The tube end portion of each annular arc tube in the vicinity of the bridge junction is out of the discharge path, so that it becomes a cold spot, and the tube end portion of the annular arc tube 41a in the vicinity of the bridge junction 42a becomes the coldest point of the arc tube 41.

In the case of the 72 W fluorescent lamp shown in the present embodiment, the arc tube 41 has an annular arc tube 41a, 41b, 41c having an outer diameter of 20.0 mm, an annular arc tube 41a having an outer diameter of 354 mm, and an annular inner diameter. Is 318mm, the outer diameter of the annular arc tube 41b is 308mm, the inner diameter of the ring is 272mm, the outer diameter of the annular arc tube 41c is 262mm, the inner diameter of the ring is 226mm, the outer diameter of the bridge joints 42a and 42b is 9.0mm, the inner diameter Is 6.0 mm, the gaps S ₁ and S ₂ between the tube walls of the annular arc tubes 41a, 41b and 41c are 5.0 mm, and the distance between one discharge path formed by the electrodes 65a and 65b is 2570 mm. It is.

  FIG. 3 is a cross-sectional view of the arc tube 41 at the position indicated by AA in FIG. 1, and shows cross sections of the annular arc tubes 41a, 41b, 41c on the tube end side from the bridge joint portion 42a. As is apparent from the drawing, the tube end portion on the bridge joint portion 42a side of the outermost annular arc tube 41a is long in the vertical direction of the arc tube 41 (for example, 22.0 mm) and short in the radial direction (for example, 18.3 mm). ) It has an elliptical shape. This elliptical shape can be manufactured by, for example, molding. In the following, the major axis of the ellipse is 41al and the minor axis is 41as. And the lowest side of the pipe | tube end part by the side of the bridge | bridging part 42a of the annular arc_tube | light_emitting_tube 41a becomes the coldest point 51, and the metal mercury 52 has gathered at the coldest point 51.

  FIG. 4 is a diagram showing the relationship between the coldest spot temperature of the arc tube 41 and the total luminous flux (relative value). As can be seen, the total luminous flux (relative value) is maximized when the coldest spot temperature is about 50 ° C., so the luminous efficiency is good. When the coldest spot temperature exceeds about 60 ° C., the total luminous flux (relative Value) is deteriorated and luminous efficiency is deteriorated. For this reason, when the coldest spot temperature exceeds 50 ° C., it is understood that the luminous efficiency can be improved by lowering the coldest spot temperature.

  In a normal fluorescent lamp, when a lamp current of about 150 to 320 mA is supplied, since the lamp current is small with respect to the length of the discharge path of the arc tube, an increase in the tube wall temperature of the arc tube is suppressed, and the coldest spot An increase in temperature is also suppressed. For this reason, under the normal temperature environment, the coldest spot temperature of the fluorescent lamp does not exceed 55 ° C., and high luminous efficiency is maintained. On the other hand, when a normal fluorescent lamp is mounted on a sealed appliance, even if the same lamp current is used, the atmosphere in the sealed appliance rises due to the heat generated by the fluorescent lamp, and the coldest is caused by the high temperature atmosphere. As a result of heating the spots, the coldest spot temperature rises, causing a problem that the luminous efficiency is lowered.

  Next, with reference to FIG. 5, when the fluorescent lamp 40 of this embodiment is lit in a sealed appliance having an initial ambient temperature of 25 ° C., the sectional shape and the coldest spot temperature of the tube end portion of the annular arc tube 41a Explain the relationship. Here, an example in which the fluorescent lamp 40 is 72 W and three kinds of lamp currents (320 mA, 220 mA, and 150 mA) are supplied thereto will be introduced.

  First, the relationship between the cross-sectional shape of the annular arc tube 41a and the coldest spot temperature when the fluorescent lamp 40 is turned on using a lamp current of 320 mA will be described. As shown in FIG. 5, when the cross-sectional shape of the annular arc tube 41a is a perfect circle (minor axis 41as / major axis 41al = 1), the coldest spot temperature is about 58 ° C. The coldest spot temperature decreases as the minor axis 41as / major axis 41al is reduced. When the minor axis 41as / major axis 41al = 0.83, the coldest spot temperature decreases by approximately 0.6 ° C. and decreases to approximately 57.4 ° C. It becomes. As described in FIG. 4, when the coldest spot temperature exceeds about 50 ° C., the emission efficiency is improved by lowering the temperature. Therefore, the issue efficiency can be increased by reducing the minor axis 41as / major axis 41al. I understand. In FIG. 5, the reason why the lower limit of the minor axis 41as / major axis 41al is 0.83 is that when the arc tube 41 is deformed by molding, the minor axis 41as becomes shorter and the major axis 41al becomes longer. The value of the short diameter 41as / the long diameter 41al when the long long diameter 41al contacts the base is 0.83, and if it exceeds this, the arc tube 41 cannot be stored in the base 43. .

  Similarly, when the lamp current of 220 mA is used and the minor axis 41as / major axis 41al is changed from 1 to 0.83, the coldest spot temperature is lowered from about 56 ° C to about 55.3 ° C by about 0.7 ° C. Further, when the lamp current of 150 mA is used and the minor axis 41as / major axis 41al is changed from 1 to 0.83, the coldest spot temperature is also lowered from about 53.9 ° C. to about 53.1 ° C. by about 0.8 ° C.

  As described above, according to the configuration of the present embodiment, the coldest spot temperature can be lowered by reducing the minor axis 41as / major axis 41al at the tube end of the fluorescent lamp 40 in any lamp current. It is possible to approach the coldest spot temperature at which the total luminous flux (relative value) is maximized to about 50 ° C., and to increase the luminous efficiency.

  In the above embodiment, an example in which only the tube end portion of the ring-shaped arc tube 41a is deformed has been described. However, even if the entire ring-shaped arc tube 41a is deformed as shown in FIG. Can be obtained. In addition, although the embodiment has been described by taking the number of arc tubes as three, the present invention is not limited to three, but can be applied to a similar annular fluorescent lamp in which a plurality of arc tubes of three or more are connected.

40 fluorescent lamp 41 arc tube 41a, 41b, 41c annular arc tube 42 bridge joint 43 base 44 adhesive 51 coldest spot 52 metal mercury 65a, 65b electrode

Claims (4)

A plurality of ring-shaped arc tubes having different ring diameters, a connecting portion for connecting the plurality of ring-shaped arc tubes, an electrode provided at the tube end of the outermost ring-shaped arc tube via the connection portion, and an innermost ring shape A fluorescent lamp comprising a discharge path connecting electrodes provided at the tube end of the arc tube,
Of the tube ends of the outermost annular arc tube, the tube end not provided with the electrode is provided at a position off the discharge path, and the tube end without the electrode has an elliptical cross section. A fluorescent lamp characterized by being. The fluorescent lamp according to claim 1, wherein
The fluorescent lamp, wherein the long axis of the ellipse is provided so as to be perpendicular to a concentric surface of the fluorescent lamp.   Three or more annular arc tubes having different ring diameters are positioned substantially concentrically on substantially the same plane, and the tube ends of the annular arc tube are sequentially connected by a bridge joint, One discharge path is formed by the electrodes provided at the tube ends of the innermost ring-shaped arc tube, and the exhaust tube is provided at the electrode at the tube end of the ring-shaped arc tube, and the tube end of the ring-shaped arc tube A plurality of bridge joints are provided, and two or more uniform gaps S are provided between the tube walls of the annular arc tube. In the gap S, the tube walls are fixed to each other by an adhesive or the like in at least one place, the maximum outer diameter of the annular arc tube of the outermost ring does not exceed 408 mm, the discharge path is longer than 2500 mm, and Fluorescent lamp with lamp current in the range of 150-320mA In the outermost ring-shaped arc tube, the length a perpendicular to the concentric surface of the ring in the partial tube cross-sectional shape on the opposite side of the discharge path from the bridge junction portion is the surface of the concentric circle of the ring A fluorescent lamp having a length greater than the parallel length b. The fluorescent lamp according to claim 3, wherein
2. The fluorescent lamp according to claim 1, wherein the major axis and the minor axis of the arc tube diameter have a relationship of 0.83 <minor axis / major axis <1.