JPH04249846A - flat fluorescent lamp - Google Patents

Abstract

PURPOSE:To provide the optimum luminous efficiency by preventing the lowering of the coldest part temperature than the optimum temperature wherein the optimum luminous efficiency or the optimum mercury vapor pressure is exhibited. CONSTITUTION:The coldest part is neared to a positive column 18 by shortening a length 1, from one end of flat bulbs 12a and 12b where the coldest part is formed to the center axis Ob of a communication part 13, than the short diameter (inner diameter) Ds of the flat cross section of the flat bulbs 12a and 12b.

Description

[Detailed description of the invention]

[Object of the invention]

0002

[Field of Industrial Application] The present invention relates to a flat fluorescent lamp in which one end of a plurality of flat bulbs are integrally connected in the lateral direction by a connecting part to bend a discharge path, and in particular, the present invention relates to a flat fluorescent lamp in which one end of a plurality of flat bulbs is integrally connected in the horizontal direction by a connecting part to bend a discharge path. Regarding flat fluorescent lamps.

0003

2. Description of the Related Art Conventionally, there is a fluorescent lamp of this type having a curved discharge path as shown in FIG. Body membranes are applied over almost the entire length and arranged in parallel, and a pair of electrodes 3a and 3b are sealed inside each end.

[0004] Also, the other ends of these valves 2a and 2b (
In Fig. 5, the upper ends) are integrally connected in the lateral direction by a connecting part 4 formed by blowing out the burner, etc., and both valves 2
The air in a, 2b and the connecting portion 4 is exhausted through an exhaust pipe 5, and after the exhaust, mercury and rare gas are sealed.

[0005] However, in such a fluorescent lamp, when the bulbs 2a and 2b have a small diameter, the inner volume of the tube is small.
There is a problem in that the temperature of the wall of the discharge tube during lighting increases to a temperature exceeding the optimum mercury vapor pressure at which the optimum luminous efficiency is exhibited, thereby reducing the luminous efficiency. Therefore, JP-A-55-13
In the low pressure mercury vapor discharge lamp described in Publication No. 3744,
The length A from one end of the valves 2a, 2b where the coldest part is formed to the central axis 4a of the connecting part 4 is set to 1 to 4 times the inner diameter of the valves 2a, 2b, and A relatively low-temperature coldest section is formed at the upper end in the figure, and the mercury vapor pressure inside the tube is controlled to an optimum value here.

[0006] Furthermore, mercury vapor pressure is controlled to an optimum value by sealing mercury amalgam 6 in the exhaust pipe 5 near the electrodes 3a, 3b.

[0007]

[Problems to be Solved by the Invention] However, such conventional fluorescent lamps do not achieve the above-mentioned optimal luminous efficiency when the bulbs 2a and 2b are circular tubes in which the cross-sectional shape is circular as shown in FIG. However, when the cross-sectional shape of the bulbs 2a, 2b is not circular but flat, there is a problem that the temperature of the coldest part becomes lower than the optimum temperature at which the optimum luminous efficiency or the optimum mercury vapor pressure is exhibited.

That is, as shown in FIG.
, 2b are circular tubes, a solar column 7 passing through the bulbs 2a, 2b is formed approximately concentrically around the central axis O of the bulbs 2a, 2b.

The coldest part is formed on the outer peripheral edge of the upper end of the bulbs 2a and 2b in FIG.
The distance from the positive column 7 to the outer circumferential edge of the upper end of bulbs 2a and 2b is the same at any position on the outer circumferential edge of bulbs 2a and 2b, so the coldest part is located somewhere on the outer circumferential edge of bulbs 2a and 2b. It is formed.

On the other hand, when the cross-sectional shape of both the bulbs 21a and 2b is an oblate circle, the positive column 7 is not an oblate circle but is almost a perfect circle, and the diameter of the perfect circle is equal to the minor axis of the oblate circle. (inner diameter).

Therefore, when the cross-sectional shape of both the bulbs 2a and 2b becomes flat, the ends in the longer diameter direction become the positive column 7.
Therefore, the coldest portion is formed at the outer end in the major diameter direction at the upper end of the valves 2a and 2b in FIG.

However, the temperature of the coldest part of this flat bulb decreases as it is further away from the positive column 7 compared to a circular bulb, and the temperature of this coldest part does not reach the optimum luminous efficiency or the optimum mercury vapor pressure. There is a problem that the temperature is lower than the optimum temperature when exhibiting , and the luminous efficiency is reduced.

On the other hand, in recent years, flat bulbs have been increasingly used due to thinner lighting fixtures and improved design.
It is required to maintain the temperature of the coldest part of this flat bulb at an optimum temperature to achieve optimum luminous efficiency.

[0014] The present invention has been made in consideration of the above circumstances, and its purpose is to maintain the temperature of the coldest part at the optimum temperature at which the optimum luminous efficiency or optimum mercury vapor pressure is exhibited, and to achieve the optimum luminous efficiency. The objective is to provide a flat fluorescent lamp that provides the following.

[Configuration of the invention]

[0016]

[Means for Solving the Problems] In order to solve the above problems, the present invention is constructed as follows.

That is, the present invention provides a plurality of flat bulbs having a flat cross section and arranged in parallel in parallel, and a connection that integrally connects one ends of these flat bulbs so as to be perpendicular to their central axes. In the flat fluorescent lamp having a section, the length from one end of the flat bulb where the coldest part is formed to the central axis of the connecting part is shorter than the inner diameter in the short axis direction of the flat cross section of the flat bulb. It is characterized by what it did.

[0018]

[Operation] When the flat fluorescent lamp is turned on, a positive column is formed in succession at the plurality of flat bulbs and the connecting portions.

The positive column is formed in a concentric circle around the central axis of the flat bulb, and its diameter is defined by the inner diameter of the flat bulb in the minor axis direction.

For this purpose, the coldest part is formed at the outer end in the vertical direction at one end of the flat bulb far from the outer peripheral edge of the positive column.

However, since the length from one end of the flat bulb where this coldest part is formed to the central axis of the connecting part is shorter than the short axis (inner diameter) of the flat bulb, the coldest part is exposed to sunlight. approaching the pillar.

For this reason, the temperature of the coldest part increases as the coldest part approaches the positive column, and the temperature of the coldest part is prevented from decreasing below the optimum temperature at which the optimum luminous efficiency or the optimum mercury vapor pressure is exhibited. It is possible to maintain the temperature of the cold part at an optimum temperature and provide optimum luminous efficiency.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 is a plan view showing the overall configuration of an embodiment of the present invention. In the figure, a flat fluorescent lamp 11 is constructed by, for example, two straight flat bulbs 12a and 12b made of glass separated by a required distance. They are placed almost parallel to each other.

These flat valves 12a and 12b are made of flat tubes as shown in FIG. 2, and their left ends in FIG.
They are integrally connected via a communication portion 13 formed by blowing out a burner or the like, and the respective inner cavities are communicated with each other.

Flat valves 12a, 12b and communication portion 1
A phosphor film (not shown) is entirely coated on the inner circumferential surface of the bulb 3 over almost the entire length, and a pair of electrodes 14a, 14b are implanted in the right end portions of the flat bulbs 12a, 12b in FIG. The glass stems 15a and 15b are hermetically sealed.

A pair of glass stems 15a, 15b are integrally fixed to the opening inner ends of exhaust pipes 16a, 16b, and the air in the flat valve 12a and the communication portion 13 is exhausted through these exhaust pipes 16a, 16b. After evacuation, rare gas is filled in, and one exhaust pipe 16a is filled with mercury amalgam 17.

Then, as shown in FIG. 3, the flat valve 12
a, 12b have a cross-sectional shape formed into an oblong flat shape with a short axis (inner diameter) Ds and a long axis (inner diameter) Dl, and the positive column 18 in the flat bulbs 12, 12b is formed by each flat bulb 1.
It is formed concentrically around the central axis Oa of 2a, 12b,
The diameter of the positive column 18 is the short diameter D of the flat bulbs 12a and 12b.
Defined by s.

Therefore, in this embodiment, the length l from the central axis Ob of the communicating portion 13 to the left end of the flat valves 12a, 12b in FIG. 1 is shorter than the short diameter Ds of the flat valves 12a, 12b, that is, l< It is set to Ds.

For this reason, the left ends of the flat bulbs 12a and 12b, where the coldest portions are formed, approach the central axis Ob of the communication portion 13, and the coldest portions move slightly closer to the positive column 18. The temperature of the coldest part is increased to prevent the temperature of the coldest part from falling below the optimum temperature at which the optimum mercury vapor pressure is exhibited.

FIG. 4 shows the flat fluorescent lamp 11 of this embodiment.
It shows the correlation between the length l to the coldest part of the lamp and the relative luminescence amount (%), and the ambient temperature of the flat fluorescent lamp 11 is approximately 25°C (normal temperature) for curve A, and approximately 25°C (normal temperature) for curve B. respectively indicate approximately 40°C.

The data in FIG. 4 was obtained from experiments conducted under the following conditions.

That is, the total length of the flat fluorescent lamp 11 is 2
10 mm, the short axis (inner diameter) Ds of the two flat bulbs 12a, 12b is 6 mm, the long axis (inner diameter) Dl is 15 mm, and the circumference is about 36.8 mm, and a perfect circle with the same circumference. The diameter of the lamp is approximately 11.7 mm, and the lamp current is 200 mm.
It is mA.

As shown in FIG. 4, a flat fluorescent lamp 1
At room temperature, where the ambient temperature of No. 1 is approximately 25°C, the relative light emission peaks when the length l to the coldest part is 5 mm, that is, 100
%, which is 1 mm shorter than the short diameter Ds of 6 mm of the flat valves 12a and 12b. And this length l
If the length l is shorter than 5 mm, the temperature will be higher than the optimum temperature because the coldest part is closer to the positive column 18, but on the other hand, if the length l is 5 mm
If the length is longer, the temperature of the coldest part will be lower than the optimum temperature as the coldest part is further away from the positive column 18, and in either case, the relative light emission will decrease, but when the length l is about 11 mm or less, It has reached 80% or more of the minimum light emission amount. The temperature of the coldest part at this time was about 50°C.

That is, according to this embodiment, the communication section 1 is connected from the left end in FIG. 1 where the coldest section of the flat fluorescent lamp 11 is formed.
3 to the central axis Ob of the flat valves 12a, 12.
By making the minor axis Ds of b shorter than the short axis Ds, the coldest part is brought closer to the positive column 18, so the temperature of the coldest part is increased accordingly, and is lower than the optimum temperature when exhibiting the optimum luminous efficiency or the optimum mercury vapor pressure. can also be prevented from decreasing.

[0036] Therefore, the temperature of the coldest part can be maintained at the optimum temperature and optimum luminous efficiency can be achieved.

[0037]

Effects of the Invention As explained above, in the present invention, the length from one end of the flat valve where the coldest part is formed to the central axis of the connecting part is longer than the short axis (inner diameter) of the flat cross section of the flat valve. Since the length is also shortened, the coldest part can be brought closer to the positive column inside the flat bulb.

Therefore, the temperature of the coldest part can be prevented from lowering below the optimum temperature at which the optimum luminous efficiency or optimum mercury vapor pressure is exhibited, and the optimum temperature can be maintained. As a result, optimum luminous efficiency can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the overall configuration of a flat fluorescent lamp according to the present invention.

FIG. 2 is a diagram seen from the left side of FIG.

FIG. 3 is a cross-sectional view of the flat valve shown in FIGS. 1 and 2.

FIG. 4 is a graph showing the correlation between the length from the coldest part to the central axis of the communicating part and the relative light emission amount in the embodiment shown in FIG.

FIG. 5 is a front view of a conventional circular tubular fluorescent lamp.

6 is a schematic cross-sectional view of the fluorescent lamp shown in FIG. 5. FIG.

[Explanation of symbols]

11 Flat fluorescent lamp 12a, 12b flat valve 13 Communication part 18 Sunlight Pillar Ds Short diameter (inner diameter) Dl Long diameter (inner diameter)

Claims (1)

[Claims] Claim 1: A plurality of flat bulbs having a flat cross section and arranged in parallel in parallel, and a connecting part that integrally connects one ends of these flat bulbs so as to be perpendicular to their central axes. The flat fluorescent lamp is characterized in that the length from one end of the flat bulb where the coldest part is formed to the central axis of the connecting part is shorter than the inner diameter in the short axis direction of the flat cross section of the flat bulb. A flat fluorescent lamp.