JPH055634Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The present invention relates to a fluorescent lamp having a bulb bent into a desired shape, and in particular, to improve the light distribution characteristics in the axial direction of the bulb. The invention relates to fluorescent lamps.

(Prior Art) Conventionally, this type of fluorescent lamp has been developed as a backlight for illuminating the back side of display boards such as liquid crystal displays, advertising boards, and nameplates. It is bent into an inverted U shape.

That is, a conventional fluorescent lamp is constructed as shown in FIGS. 5A to 5C, and includes, for example, two straight pipe-like straight portions 1a and 1b of a bulb 1 whose cross section is formed into a flat shape such as an ellipse. are arranged side by side on the same plane,
The connecting ends (upper ends in FIG. 5) of these straight portions 1a and 1b are integrally connected to each other via a substantially flattened inverted U-shaped bent portion 1c.

A pair of electrodes 2a, 2b are sealed at each sealed end (lower end in FIG. 5) of each straight portion 1a, 1b, and a phosphor film made of phosphor is formed on the inner peripheral wall of the bulb 1. It is coated over almost the entire length of the valve 1,
The bulb 1 is filled with rare gases such as mercury and argon.

In this conventional fluorescent lamp, the cross section of the bulb 1 in the direction perpendicular to the axis, that is, the cross section, is formed in a flat shape such as an ellipse. In comparison, it is possible to obtain light distribution characteristics close to those of a surface light source.

(Problem that the invention attempts to solve) However, in such conventional fluorescent lamps, in order to obtain light distribution characteristics closer to those of a surface light source,
In addition to the necessity of providing a plurality of discharge paths 3, there is a problem in that the discharge path 3 shown by the broken line in FIG.

That is, the discharge path 3, which is the path of the positive column, tries to pass through the shortest path between the pair of electrodes 2a and 2b, and is deflected toward the inner circumferential side at the curved portion 1c of the bulb 1.

Therefore, in the curved portion 1c of the bulb 1, the phosphor film on the inner peripheral side close to the discharge path 3 is strongly excited and emits light with increased luminous intensity, while the outer peripheral portion of the curved portion 1c is exposed to the discharge path 3. There is a problem that light is emitted with reduced luminous intensity due to the distance between the two, resulting in a difference in brightness between the inner and outer peripheries.

That is, the light distribution characteristics in the axial upper part X, middle part Y, and lower part Z of the bulb 1 shown in FIG. 6A are different as shown in FIG. 6B, and the light distribution characteristics in the axial direction of the bulb 1 are different. However, there is a problem in that the brightness in the axial direction of the bulb 1 is uneven.

This phenomenon is a special phenomenon that occurs when the bulb has a flat cross section.

Therefore, an object of the present invention is to provide a fluorescent lamp that can improve the light distribution characteristics in the axial direction of the bulb with a simple configuration.

[Structure of the idea]

(Means for Solving the Problems) The present invention was developed by focusing on the fact that the beam of light generated between a pair of electrodes passes approximately through the axial center of the bulb, including the center of gravity of the cross section. It is configured as follows.

That is, in the present invention, a plurality of straight parts having flat cross sections are arranged side by side so that their diametrical directions are parallel to each other, and the connecting ends of these straight parts are bent at a predetermined angle. In addition to connecting through the
In a fluorescent lamp in which a bulb is constructed by providing one or more curved portions, the cross-sectional center of gravity of the portion connected to the straight portion of the curved portion is determined by the cross-sectional center of gravity of the portion connected to the straight portion of the curved portion. It is characterized by being eccentric toward the outer periphery from the center of gravity of the surface.

(Operation) When a required lamp current is applied between a pair of electrodes of a fluorescent lamp, a positive column is generated between a pair of electrodes in a bulb.

This positive column passes through the cross section of the bulb in the direction perpendicular to its axis, that is, the axial center that includes the center of gravity of the cross section.
In the curved portion of the bulb, the light beam passes eccentrically toward the outer circumference than the straight portion, and can prevent the positive column from approaching the inner circumference of the curved portion.

Therefore, since the positive column passes through the center of gravity of the curved portion of the bulb, it almost eliminates the difference in brightness between the inner and outer circumferential sides of the curved portion of the bulb, and improves the light distribution characteristics in the bulb axis direction. can be improved.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

FIGS. 1A to 1C show the overall configuration of an embodiment of the present invention, in which a glass bulb 10 is formed into an approximately inverted U shape, and a phosphor film 11 made of phosphor is formed on the inner circumferential wall of the bulb 10. is coated over almost the entire circumference and entire length, and rare gases such as mercury and argon are sealed inside the bulb 10, and a pair of electrodes 12a and 12b are sealed at both ends of the bulb 10, respectively.

The valve 10 has, for example, two straight parts 1 in the shape of a straight pipe.
3 and 14 are arranged side by side on the same plane with a gap d ₁ ,
As shown in the bottom view of FIG. , the cross section along the direction perpendicular to the axis is also formed into an oval flat shape as shown in FIG. It is formed with an outer diameter D1 in the major axis direction over the entire length, and is formed with the same thickness.

The connecting ends 13a, 14a of the straight parts 13, 14 (upper ends in FIG. 1A) are bent parts 15 in the shape of a flat inverted U.
each straight part 1 is integrally connected to both ends of the straight part 1.
The inner cavities of the valves 3 and 14 communicate with each other through the inner cavity of the bent portion 15, and the valve 10 as a whole forms an inverted U-shaped inner cavity.

The inner circumferential surface 15a _side of the curved portion 15 is constricted into a concave arc shape as _shown in _{FIG .} The cross section of the curved portion 15 where the curve is set, that is, the cross section along the direction perpendicular to the axis, is the outer circumferential surface 1 as shown in FIG. 2B.
It is formed in a flat shape that gradually tapers from the 5b side toward the inner circumferential surface 15a side.

The outer diameter in the major axis direction of the flattened cross section of this curved portion 15
D ₂ is smaller than the outer diameter D ₁ in the major axis direction of the flat cross section of each straight portion 13 and 14 by the amount constricted on the inner circumferential surface 15a side, and the center of gravity OB of the flat cross section of the curved portion 15 is is the center of gravity (center) of each straight portion 13, 14
It is slightly eccentric, for example, α, toward the outer circumferential surface 15b from OA.

A positive column passes through the center of gravity OB of the flat longitudinal section of the curved portion 15 and its surroundings, forming a discharge path 16.

An example of a method for manufacturing the valve 10 of this embodiment configured as described above is shown in FIGS. 4A to 4F.

First, as shown in FIG. 4A, the upper end openings of straight sections 13, 14 made of glass and having a flat cross section are opened in the direction of the arrow, for example, in the flames of a plurality of fixed burners 20, 20. It is rotated, heated and melted, and sealed as shown in FIG. 4B.

Next, as shown in FIG. 4C, a flame is blown out in the left-right direction between two pairs of straight parts 13 and 14 that are arranged in parallel on the same plane and fixed by a required jig (not shown). Insert the two-pronged burner 21,
The inner upper end portions of the straight portions 13 and 14 are heated and softened almost simultaneously, and the two-pronged burner 2 is heated as shown in FIG. 4D.
After stopping the heating by 1, each straight part 13, 1
Air at a predetermined pressure is blown in the direction of the arrow from the opening at the lower end of No. 4 to blow out each heated and softened portion.

As a result, protrusions 13a and 14a that protrude inward are provided at the upper ends of each straight portion 13 and 14, and constricted portions 13b and 14b that are constricted in an arc shape are provided below each protrusion 13a and 14a. is formed.

After this, as shown in FIG. 4E, each protrusion 13
The open ends of the tips a and 14a are butted against each other and connected to form the curved portion 15.

The connection portion of this curved portion 15 is heated again by the burner 20 to anneal it, and the curved portion 15 is inserted into a mold (not shown) and molded, thereby making the shape uniform. Figure F
It is formed into an inverted U-shaped valve 10 as shown in FIG.

Thereby, the wall thickness of the bulb 10 can be made almost uniform, distortion can be reduced, and mechanical strength can be increased.

Next, the operation of this embodiment will be described.

When a required lamp current is applied between the pair of electrodes 12a, 12b of the bulb 10, a positive column is generated between the pair of electrodes 12a, 12b inside the bulb 10.

This positive column is the cross section of the bulb 10, that is,
Since the discharge path 16, which is the path of the positive column, is formed as shown by the broken line in FIG. 1A, it passes through the axis including the center of gravity of the cross section in the direction perpendicular to the axis.

Therefore, the discharge path 16 has both straight parts 13 and 14.
The curved portion 15 is formed along the axial direction at the center of gravity OA portion and the center of gravity OB portion of these flat cross sections, respectively, and the center of gravity OB of the curved portion 15 is separated from the center of gravity OA of both straight portions 13 and 14. Since the discharge path 16 is eccentric toward the outer circumferential surface 15b, the discharge path 16 is formed eccentrically toward the outer circumferential surface 15b in the curved portion 15.

This prevents the discharge path 16 from being deviated toward the inner circumferential surface 15a of the curved portion 15, and can almost eliminate the difference in brightness between the inner circumferential side and the outer circumferential side.

Therefore, according to this embodiment, the light distribution characteristics of the upper part X, middle part Y, and lower part Z in the axial direction of the bulb 10 are almost the same as shown in FIG. 3B, as shown in FIG. 3A. , almost uniform light distribution characteristics can be obtained in the axial direction of the bulb 10.

Although the above embodiment describes the case where the valve 10 is formed into an inverted U-shape, the present invention is not limited to this. For example, the valve 10 may be bent into an approximately S-shape, approximately an M-shape, etc. and make the curve part 2.
It can also be applied when more than one location is provided.

[Effect of idea]

As explained above, the present invention makes the cross-sectional center of gravity of the portion of the curved portion of the valve connected to the straight portion eccentric to the outer circumferential side than the cross-sectional center of gravity of the straight portion connected to the curved portion. Therefore, it is possible to prevent the positive column passing through the curved portion from being deviated toward the inner peripheral side of the curved portion.

This makes it possible to equalize the light distribution characteristics in the curved portion and the light distribution characteristics in the straight portion,
The light distribution characteristics in the bulb axis direction can be made almost equal.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the fluorescent lamp according to the present invention, where A is a longitudinal cross-sectional view, B is a right side view, C is a bottom view, and FIG. 2A is a line A-A in FIG. 2B is an end view taken along the line B--B of FIG. 1A, and FIGS. 3A and 3B are schematic diagrams showing the light distribution characteristics of the embodiment shown in FIG. Figure 4 A to F are the first
A process diagram showing an example of a method for manufacturing the valve shown in the figure,
Figure 5 shows a conventional fluorescent lamp, where A is a front view, B is a right side view, C is a bottom view, and Figures 6A and B.
5 is a schematic diagram showing the light distribution characteristics of the conventional example shown in FIG. 5. FIG. 10...bulb, 11...phosphor film, 12a,
12b... Electrode, 13, 14... Straight portion, 15...
...Curved part, 16...Discharge path, OA...Centroid of cross section of both straight parts, OB...Centroid of cross section of bent part.

Claims (1)

[Claims for Utility Model Registration] 1. A plurality of straight parts having flat cross sections are arranged in parallel so that their diametrical directions are parallel, and the connecting ends of these straight parts are bent at a required angle. In a fluorescent lamp in which a bulb is constructed by connecting via a curved portion and having one or more curved portions, the center of gravity of the cross section of the portion connected to the straight portion of the curved portion is defined as It is characterized by being eccentric toward the outer periphery of the cross-sectional center of gravity of the straight portion connected to the curved portion. 2. The fluorescent lamp according to claim 1, wherein the curved portion has a cross-sectional shape that gradually tapers from the outer circumferential side toward the inner circumferential side.