JP4846260B2 - Method for manufacturing double spiral arc tube, double spiral arc tube and double spiral fluorescent lamp - Google Patents

Description

  The present invention relates to a method for manufacturing a double spiral arc tube, a double spiral arc tube, and a double spiral fluorescent lamp.

In recent years, various compact fluorescent lamps have been developed as energy- and resource-saving light sources in the lighting field. Among them, a fluorescent lamp (hereinafter, referred to as “double spiral fluorescent lamp”) having an arc tube having a substantially disc shape in appearance and having a double spiral discharge path has attracted attention.
Such a double spiral fluorescent lamp is more compact than a conventional annular fluorescent lamp that emits the same luminous flux, and has a preferable light distribution in which the irradiated surface is circular. As an application, it can be applied to a downlight directly attached to a ceiling in a store / house lighting or the like.
JP-A-9-92154 German patent 860675 German patent 871927

  The arc tube of the double spiral fluorescent lamp is a double tube having a generally conical shape in appearance by first winding a softened glass tube in a double spiral shape along the conical surface of a substantially conical shape forming jig. It is manufactured by forming a spiral body and then deforming the double spiral body into a substantially disk shape by applying pressure or the like. It is desirable in terms of appearance that the gap between the tubes in the spiral portion of the arc tube is substantially constant.

  By the way, according to the study of the present inventor, the arc tube of the double spiral fluorescent lamp having a substantially disc-like appearance manufactured by the conventional manufacturing method surrounds the S-shaped part at the center of the spiral part. The gap between the innermost winding part and the winding part that faces this winding part and is one outside of the winding part is the gap between the other pipes, that is, outside the innermost winding part. It has been found that there is a problem that the gap between the tubes in the spiral portion is narrower than the gap between the tubes in the spiral portion, and the gap between the tubes in the spiral portion is not uniform as a whole.

According to the inventor's study, the problem is that when the central portion of the double spiral body having a substantially conical shape in appearance is bulged to form the bulging portion, It was found that the cause was that the boundary portion between the S-shaped part of the part and the innermost winding part swelled locally.
The present invention has been made in view of the above-described problems, and in the method of manufacturing a double spiral arc tube, the innermost winding portion surrounding the central S-shaped portion of the spiral portion, The gap between the winding portion facing the winding portion and the winding portion on the one outer side of the winding portion is larger than the gap between the tubes in the spiral portion located outside the innermost winding portion. An arc tube manufacturing method capable of preventing arc narrowing and obtaining an arc tube having substantially the same gap between the tubes in the spiral portion, an arc tube having substantially the same gap between the tubes in the spiral portion, and the arc tube An object of the present invention is to provide a double spiral fluorescent lamp having an excellent appearance and shape.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a method for producing a double spiral arc tube, wherein the central portion of a softened glass tube is placed on the top of a substantially conical shaped forming jig. In a locked state, the glass tube is wound along the conical surface of the forming jig to form a double helix having a substantially conical shape in appearance, and glass as the double helix And a second step of deforming the tube into a flat shape until the tube axis is aligned on a substantially flat surface, wherein the double spiral central portion is formed in the first step. A gap between the innermost first winding part that surrounds the S-shaped part and the second winding part that faces the first winding part and is located outside one of the first winding parts, The forming jig while keeping the gap wider than the gap between the winding portions located outside the first winding portion. And wherein the winding the glass tube.

  According to a second aspect of the present invention, there is provided a method of manufacturing a double spiral arc tube according to the present invention, wherein the top of the forming jig is S-shaped. And a double spiral guide path extending from both ends of the lock path is formed on the conical surface. The guide path is formed between a bottom wall and a bottom wall. A vertical wall rising from the innermost part, and in the first step, the glass tube is wound along the vertical wall of the taxiway, and the innermost first vertical wall of the taxiway And the distance between the first vertical wall and the second vertical wall of the guide path located nearest to the first vertical wall is wider than the distance between the vertical walls outside the first vertical wall.

In order to achieve the above object, a double spiral arc tube according to claim 3 is manufactured by the arc tube manufacturing method according to claim 1 or 2.
Furthermore, the double spiral arc tube according to claim 4 is the double spiral arc tube according to claim 3, wherein a gap between the tubes in the spiral portion of the double spiral arc tube is 1. 0.0 mm to 2.0 mm.

  A double spiral fluorescent lamp according to claim 5 includes the double spiral luminous tube according to claim 3 or 4.

  According to the method for manufacturing a double spiral arc tube according to the present invention, in the first step of forming a double helix having a substantially conical shape in appearance by winding a softened glass tube around a forming jig, An innermost first winding part that surrounds the S-shaped part of the center of the double helix, and a second winding part that faces the first winding part and is located outside one of the first winding parts In order to wind the glass tube around the forming jig while keeping the gap between the winding parts positioned outside the first winding part, the tubes in the spiral part of the double helix It is possible to set substantially the same gap.

  In this way, the double helix formed in the first step and having a substantially conical shape in appearance has substantially the same gap between the tubes, so that it is obtained by deforming flatly in the second step. It is also possible to make the gaps between the tubes in the spiral portion of the heavy spiral arc tube substantially equal.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Since the double spiral fluorescent lamp and the arc tube have a symmetric shape around a predetermined axis or point, only a part of the symmetric part may be described. Moreover, the scale between drawings may not be unified.
After describing the configuration of the double spiral fluorescent lamp, a method for manufacturing the arc tube of the lamp will be described.
1. Configuration of Double Spiral Fluorescent Lamp FIG. 1A is a plan view of a double spiral fluorescent lamp 1 according to this embodiment, and FIG. 1B is a front view of the same.

  The double spiral fluorescent lamp 1 is a tube input 25 W type, and includes a double spiral arc tube 10 and caps 20 a and 20 b attached to both ends of the arc tube 10. The bases 20a and 20b are, for example, G-type and have power connection terminal pins 21a and 21b. The double spiral fluorescent lamp 1 is attached to a lamp (not shown) via a cap 20a, 20b, and is turned on by a high frequency electronic ballast provided in the lamp.

2A is a partially broken plan view of the arc tube 10, and FIG. 2B is a front view of the same.
The arc tube 10 has a substantially disk shape when viewed from the outside, and includes an arc tube main body 100 and a pair of electrodes 5a and 5b disposed at both ends 110a and 110b of the arc tube main body 100. The arc tube 10 has an outer diameter of 9 mm, an inner diameter of 7.4 mm, a total length of 900 mm, a distance between the electrodes 5a and 5b of 780 mm, and a tube wall load of about 0.18 W / cm ² .

A phosphor layer (not shown) is formed on the inner surface of the arc tube 10, and mercury and a rare gas (not shown) are sealed therein.
For example, the phosphor layer includes phosphors that emit red (Y ₂ O ₃ : Eu ³⁺ ), green (LaPO ₄ : Ce ³⁺ , Tb ³⁺ ) and blue (BaMg ₂ Al ₁₆ O ₂₇ : Eu ²⁺ ). It is formed by applying a mixed rare earth phosphor.

Mercury, which is a luminescent substance, is sealed in the arc tube main body 100 in the form of mercury alone in an amount of 5 mg. The mercury may be enclosed in the form of amalgam such as bismuth / indium mercury in addition to the form of mercury alone.
As the rare gas, argon (Ar) is sealed in the arc tube main body 100 so that the sealing pressure is about 400 Pa. The rare gas is not limited to argon, and may be neon (Ne) or krypton (Kr), or a mixed gas obtained by mixing argon, neon, and krypton at a predetermined ratio.

  The arc tube main body 100 is made of, for example, barium strontium silicate glass (soft glass having a softening point of 675 ° C.), has a substantially circular cross section, and has a central portion 120 having an S-shaped portion, and the central portion. The two end portions 110a and 110b are opposed to each other with 120 interposed therebetween, and the winding portion 130 has a spiral portion between the both end portions 110a and 110b and the central portion 120 and has a vortex approximately fourfold.

In the arc tube main body 100, the tube axis does not necessarily need to be included in the same plane over the entire length, and at least the tube axis of the winding portion 130 may be included in the substantially same plane.
Electrodes 5a and 5b are sealed at both ends 110a and 110b, respectively. The electrodes 5a and 5b have a pair of lead wires 7a and 7b, respectively. The lead wires 7a and 7b are described above after the portion extending from the arc tube main body 100 is cut to an appropriate length. It is electrically connected to the power supply connection terminal pins 21a and 21b of the caps 20a and 20b.

  The central portion 120 corresponds to the vicinity of the midpoint of the tube axis of the arc tube main body 100 and is a portion that becomes the center of the spiral. In addition, a bulging portion 121 (maximum tube outer diameter: about 13 mm) that is thicker than the tube outer diameter (9 mm) of the winding portion 130 is formed in the central portion 120. The bulging portion 121 is formed with the coldest spot at the time of lighting, and the bulging portion particularly has a coldest spot temperature in a range of 50 ° C. to 60 ° C. at which the lamp efficiency is maximized. The shape of 121 is designed.

  Here, (1) the innermost winding portion 130a (hereinafter referred to as “first winding”) surrounding the S-shaped portion 122 of the central portion 120 in a direction parallel to the plane including the tube axis of the arc tube main body 100. And a winding portion 130b (hereinafter, referred to as "second winding portion 130b") that faces the first winding portion 130a and is positioned outside one of the first winding portions 130a. ) Is defined as a gap Ga.

More specifically, the gap Ga includes a boundary portion between the S-shaped portion 122 and the inside of the first winding portion 130a, and the first winding portion 130a and the second winding portion 130b located outside the portion. It is a gap with the boundary part.
(2) A gap between the winding portions located outside the first winding portion 130a in the direction parallel to the plane (the boundary portion between the first winding portion 130a and the second winding portion 130b, and the first winding portion 130a). The clearance between the second winding portion 130b and the third winding portion 130c, the boundary portion between the second winding portion 130b and the third winding portion 130c, the third winding portion 130c and the fourth winding portion 130c. The gap between the winding portion 130d and the boundary portion) is defined as a gap Gb. The gap Ga and the gap Gb are substantially equal.

That is, it has a desirable shape in terms of appearance such that the gaps between the tubes in the winding portion 130 which is a spiral portion are substantially equal. In addition, in order to obtain a compact outer shape and a preferable light-emitting surface with no noticeable luminance unevenness as a resource-saving surface light source, the substantially equivalent gaps Ga and Gb are narrower than 1.0 mm to 5 mm compared to a tube outer diameter of 9 mm. 0.0 mm is preferable.
In FIG. 2, different hatchings are applied to facilitate the distinction between the S-shaped portion 122 and the winding portions 130 a, 130 b, and 130 c.

Moreover, the winding part 130 has spread as it approaches the edge part 110b. That is, the gap Ge between the end portion 110b to which the electrode 5b is sealed and the tube adjacent to the end portion 110b is longer than Ga and Gb.
This is because when the gap Ge is made wider than the gap Gb to some extent (for example, the gap Ge is about 3 to 10 mm), the end 110b is heated by a burner or the like in the electrode sealing step. This is because the occurrence of defects such as cracks and leaks in the glass tube can be prevented. Moreover, it is for making it easy to attach the caps 20 a and 20 b to the arc tube 10.
2. 2. Manufacturing Method of Double Spiral Fluorescent Lamp 1 Next, a manufacturing method of the above-described double spiral fluorescent lamp 1 will be described, particularly focusing on a manufacturing method of the arc tube 10.

(1) Overall Flow First, the overall flow of the manufacturing method of the double spiral fluorescent lamp 1 will be briefly described.
(A) Double spiral body forming step: In the double spiral body forming step, the softened glass tube is wound around a forming jig to form a double spiral body having a substantially conical shape in appearance. FIGS. 3 and 4 are views for explaining a double helix forming process for forming a softened glass tube into a double helix, and FIG. 3 (a) shows that the glass tube 300 is heated in an electric furnace 298. FIG. 3B is a diagram showing a step of dropping the glass tube 300 softened by heating on the top of the forming jig 400, and FIG. 4C is a diagram showing the step of dropping the glass tube 300 on the forming jig 400. FIG. 4D is a diagram showing the winding step, and FIG. 4D is a diagram showing the step of removing the glass tube 300 from the forming jig 400.

(B) Phosphor layer forming step: In the phosphor layer forming step, the phosphor layer is formed by applying the phosphor to the inner surface of the double helix and then baking the applied phosphor.
(C) Deformation step: In the deformation step, the double spiral body having a substantially conical shape in appearance is deformed into a disk shape in appearance. 5A and 5B are diagrams for explaining the deformation process, in which FIG. 5A shows a step of installing the double helix in the deformation device, and FIG. 5B shows a step of heating the double helix. FIG. 5C is a diagram showing a step of deforming the double helix by applying pressure.

(D) Electrode sealing step: In the electrode sealing step, the electrode is sealed to the end of the arc tube body.
(E) Base attachment step: In the base attachment step, the base is attached to the end of the arc tube created through the steps (A) to (D).
The double spiral fluorescent lamp 1 is completed through the steps (A) to (E).
(2) Double helix formation process A double helix formation process is demonstrated.

As shown in FIG. 3A, the electric furnace 298 has a large number of heaters 298a on its inner periphery. In the electric furnace 298, a straight tubular glass tube 300 having both ends held by holding members 296a and 296b is located.
A region planned to be formed in a double helix shape in this glass tube 300 (softening point 675 ° C.) (this region is hereinafter referred to as “double helix formation planned region” and is indicated as a reference symbol Fa in FIG. 3). Is heated to about 800 ° C. in an electric furnace 298.

In the electric furnace 298, the temperature at the center is the highest (this temperature distribution may vary depending on the shape of the electric furnace, the use environment, etc.). For this reason, also in the glass tube 300, the center part 301 of a longitudinal direction becomes high temperature compared with the other part.
As the heating of the glass tube 300 proceeds, the double helix formation planned area Fa begins to droop gradually.
Subsequently, as shown in FIG. 3B, the softened glass tube 300 taken out from the electric furnace 298 is transferred to above the forming jig 400.

The forming jig 400 has a substantially conical shape as viewed from the outside, and a pair of locking portions 401a and 401b and an S-shaped locking path 408 [see FIG. 6 (a)] are provided at the top. A double spiral guide path 402 is formed on the conical surface.
The hanging portion of the transferred glass tube 300 is placed in contact between the locking portions 401a and 401b.

4C, the forming jig 400 is attached to a driving device (not shown) that rotates about the rotation axis A, and the softened glass tube 300 is attached to the forming jig 400. In a state where it is installed at the top, this driving device is driven to raise the forming jig 400 while rotating it in the direction of arrow C. The rotation axis A coincides with the axis of the forming jig 400.
As a result, the central portion 301 of the glass tube 300 is locked at a position on the locking path 408 between the locking portions 401 a and 401 b, and the glass tube 300 is wound along the guide path 402 of the forming jig 400. The

At this time, in order to prevent the glass tube 300 from being crushed and deformed, a pressure-controlled gas (air), nitrogen, argon, or the like is blown into the glass tube 300.
As described above, since the temperature of the central portion 301 of the glass tube 300 is relatively high, the central portion 301 that has become particularly soft due to the high temperature is expanded by blowing the pressure gas, and the expanded portion 314 (see FIG. 5). ) Is formed.

After the winding around the forming jig 400 is completed and the temperature of the glass tube 300 is lowered and the glass is cured, the cured glass tube 300 is removed from the forming jig 400 as shown in FIG. And the part except the area | region formed in the double helix shape is cut | disconnected from the removed glass tube 300, and the double helix 310 is completed.
(3) Deformation process
The deformation process will be described in detail.

As shown in FIG. 5, the arc tube body 100 is manufactured by deforming the double helix 310 into a flat shape using a deforming device 340. The deformation device 340 includes a movable plate 341, a fixed plate 342, a plurality of guide bars 343, and a plurality of regulating members 344.
The movable plate 341 and the fixed plate 342 are made of, for example, stainless steel, and are opposed to each other up and down across the double spiral body 310. The movable plate 341 can move up and down while maintaining a state substantially parallel to the fixed plate 342. The movable plate 341 is formed with a through hole 345 in the approximate center of the movable plate 341 so that the bulging portion 314 of the double helix 310 can be accommodated.

The guide bar 343 is erected on the upper surface of the fixed plate 342 and passes through a hole (not shown) of the movable plate 341. The restricting members 344 are disposed at the four corners of the upper surface of the fixed plate 342 and restrict the movable plate 341 from being too close to the fixed plate 342.
In the deformation step, first, as shown in FIG. 5A, the double helix 310 is disposed between the movable plate 341 and the fixed plate 342. The double helix 310 is arranged at the approximate center of the upper surface of the fixed plate 342 and at a position where the bulging portion 314 of the double helix 310 is directly below the through hole 345 of the movable plate 341. At this time, the periphery of the through hole 345 in the movable plate 341 is in contact with the upper surface side of the winding part 313 of the double helix 310.

Next, in a state where the movable plate 341 is in contact with the winding part 313 of the double helix 310, the temperature of the outer peripheral surface of the double helix 310 becomes, for example, about 620, as shown in FIG. Heat like so. Reference numeral 620 denotes a temperature at which the phosphor applied to the inner surface of the double helix 310 can be baked, whereby the phosphor layer is baked on the inner surface of the double helix 310.
The heating temperature is not limited to 620, but is preferably set lower than the softening point (675) of glass (soft glass). When the temperature of the double helix 310 is equal to or higher than the softening point, the glass is deformed by its own weight, so that it is difficult to maintain the shape of the double helix 310. Further, when the temperature is raised to the vicinity of the softening point of the glass, there is a problem that the phosphor layer formed on the inner surface of the double helix 310 starts to peel off.

When the temperature of the outer peripheral surface of the double helix 310 reaches about 620, the double helix 310 can be plastically deformed, and the movable plate 341 starts to descend due to its own weight. That is, the double helix 310 is compressed in the vertical direction and starts to deform. The lowering of the movable plate 341 stops when the movable plate 341 comes into contact with the regulating member 344.
As shown in FIG. 5C, when the movable plate 341 comes into contact with the regulating member 344, the deformation of the double helix 310 into the arc tube body 100 is completed. The tube axes of the arc tube main body 100 are arranged on a substantially single plane.
3. Shape of Molding Jig 400 and Double Helical Body 300 The shape of the molding jig 400 and the double helix 310 formed using this molding jig will be described.

FIG. 6A is a plan view of the forming jig 400, and FIG. 6B is a front view of the same.
In FIG. 6A, a straight line connecting the ends of both end portions 404a and 404b passing through the top portion 405 of the forming jig 400 is denoted by reference numeral L4, and a straight line orthogonal to the straight line L4 is denoted by reference numeral L3.
The straight line L4 is substantially orthogonal to the axis A of the forming jig 400, and is substantially parallel to a plane including the tube axis of the wound portion 130 (see FIG. 2) after deformation.

The forming jig 400 has a substantially conical shape [mountain shape (a shape resembling a mountain)], and the top portion 405 (the top portion of the mountain) has a pair of locking portions 401a and 401b and an S-shaped engagement. And a stop path 408.
Guidance paths 402 extending from both ends of the locking path 408 are formed on the conical surface. The guide path 402 has a double spiral shape that turns from the locking path 408 to the end portions 404a and 404b (located at the ridge of the mountain).

  Here, the innermost guideway that surrounds the top portion 405 of the guideway 402 is defined as a first guideway 402a, and the guideway located outside the first guideway 402a is positioned further outside the second guideway 402b. The taxi paths to be performed are sequentially designated as a third taxiway 402c and a fourth taxiway 402d. In FIG. 6A, different hatching is applied to facilitate the distinction of the locking path 408, the first guide path 402a, the second guide path 402b, and the third guide path 402c.

FIG. 7 is an enlarged view of the cross section along the straight line L4 in FIG. 6A in the region E of FIG. 6B. In addition, in FIG. 7, a glass tube is shown with a virtual line.
As shown in FIG. 7, the first guide path 402a includes a bottom wall 407a and a vertical wall 403a that rises from the deepest of the bottom wall 407a (hereinafter, in order to distinguish the vertical walls, for example, (The vertical wall 403a included in the first guide path 402a may be referred to as a “first vertical wall 403a”.) The same applies to the other guide paths 402b to 402d. The shape of the vertical walls 403a to 403d may be an arc shape corresponding to the cross-sectional shape of the glass tube.

In the double helix formation step, the double helix 310 is formed by winding the glass tube along the vertical walls 403a to 403d of the guide paths 402a to 402d of the forming jig 400.
The distance Dpa in FIG. 7 is the distance between the first vertical wall 403a and the second vertical wall 403b located on the outer side and closest to the first vertical wall 403a. The interval Dpb is the interval between the vertical walls outside the first vertical wall 403a (the interval between the second vertical wall 403b and the third vertical wall 403c and the interval between the third vertical wall 403c and the fourth vertical wall 403d). .

The interval Dpa is wider than the interval Dpb (Dpa> Dpb). The reason for the difference in the distance dimension will be described in detail later.
Fig.8 (a) is a top view of the double helix 310, FIG.8 (b) is a partially broken front view in the straight line L5 of (a).
As shown in FIG. 8 (a), the double helix 310 has a spiral winding formed by a central portion 312, both end portions 311a and 311b, and a portion between the central portion 312 and both end portions 311a and 311b. It consists of a turning part 313. The double helix 310 has a substantially conical shape in appearance, and the tube axis thereof is a double helix.

The straight line L5 is a straight line passing through the ends of the end 311a and the end 311b. The straight line L5 is substantially parallel to the straight line L4 (see FIG. 6).
The central portion 312 is a portion corresponding to the central portion 120 of the arc tube main body 100 and is a portion that becomes the center of the double helix, and has an S-shaped portion 312a. Further, the central portion 120 has a bulging portion 314 having a tube outer diameter larger than that of the winding portion 313 and the end portions 311 a and 311 b, and this bulging portion 314 is connected to the bulging portion 121 of the arc tube 10. Become.

The winding portion 313 is located on the innermost first winding portion 313a surrounding the S-shaped portion 312a of the central portion 312 and facing the first winding portion 313a and outside the first winding portion 313a. The second winding part 313b and the third winding part 313c located outside the second winding part 313b.
In FIG. 8B, the gap Ga1 is a gap between the first winding part 313a and the second winding part 313b in the direction orthogonal to the axis A of the double helix 310. The gap Gb1 is a gap between the tubes further outside the first winding portion 313a in the direction orthogonal to the axis A (a gap between the second winding portion 313b and the third winding portion 313c, a third winding portion 313c. And a gap between the fourth winding portion 313d on the outside and the fourth winding portion 313d.

Since the gap Ga1 is substantially equal to the gap Gb1 (Ga1 = Gb1), it can be said that the gaps between the tubes in the winding portion 313 are substantially equal.
When the double helix 310 is deformed into a disk shape by the above-described deformation process, the gap between the tubes is deformed in a substantially maintained state, so that the arc tube body 100 (see FIG. 2) is wound. The gaps between the tubes in the turning portion 130 are also substantially equal (Ga = Gb), and the arc tube 10 that is preferable in appearance can be obtained.

The gap Ge1 is a gap between the end 311b of the double helix 310 and the winding part 313. The reason why the gap Ge1 is wider than the gap between the tubes in the winding part 313 is as described above.
4). The process of reaching the distance Dpa> the distance Dpb The present inventor has come to use a forming jig in which the interval in the winding part is set as a result of careful analysis of the conventional forming jig. Is due to.

Then, the shape of a conventionally used molding jig, the situation where a problem has occurred, etc. will be described.
(1) Shape of Conventional Molding Jig FIG. 9 is a plan view showing a conventional molding jig.
The last two digits of the numbers in the 500 series of each member of the forming jig 500 are denoted by the same reference numerals as those of the members of the forming jig 400, and description thereof is omitted. A conventional arc tube manufacturing method is manufactured in the same manner as the steps (A) to (D) described in this embodiment.

The straight line L6 is a straight line passing through the ends of the end portion 504a and the end portion 504b.
On the straight line L6, the distance between the guide paths 502 (the distance between the vertical walls) DpO is substantially equal.
In order to make the gaps between the tubes in the winding portion of the double helix to be formed using the forming jig substantially equal, it is normal to make the intervals between the guide paths of the forming jig generally equal. It was because of it.

FIG. 10A is a plan view of a double helix 610 having a substantially conical shape in appearance and formed using a conventional forming jig 500, and FIG. 10B is a partially broken front view of the straight line L7 in FIG. It is. Also in the double helix 610, the same members as those of the double helix 310 according to the embodiment are given the last two digits as in the corresponding members of the double helix 310, and the description thereof is omitted.
As shown in FIG. 10, the gap Ga1 between the first winding part 613a and the second winding part 613b outside the first winding part 613a is narrower than the gap Gb1 between the outer pipes.

As described above, when the gap between the innermost tubes of the winding part 613 is narrow, the gap between the innermost tubes can be obtained even in a light emitting tube having a substantially disc shape in appearance, which is obtained by deforming the double helix 610 into a flat shape. Only narrows and the aesthetics of the appearance are impaired. In an extreme case, a problem that the glass tube breaks due to the proximity of the adjacent portions contacting each other.
In order to meet the demand for a compact double spiral fluorescent lamp, it is required to further narrow the gap between the tubes of the winding part. It is thought that this problem has become apparent due to this compactness.

(2) Study by the Inventor According to the study by the present inventor, the gap Ga1 is narrower than the gap Gb1 because the central portion 612 of the double helix 610 bulges to form the bulge 614. It was found that there is a cause that the boundary portion between the S-shaped portion 612a and the first winding portion 613a locally bulges outside in the vicinity of the center portion 612.

In fact, when measuring the dimensions of a 9 mm tube outer diameter arc tube manufactured using the conventional forming jig 500, the S-shape is linked to the increase in the maximum outer diameter of the tube at the center to about 13 mm. The maximum heel outer diameter at the boundary portion between the shape portion 612a and the first winding portion 613a was expanded to about 11.5 mm.
Since the forming jig 400 in the present embodiment satisfies the interval Dpa> the interval Dpb (see FIG. 7), the S-shaped portion 312a and the first winding of the double helix 310 formed using the forming jig 400 are used. The boundary part with the turning part 313a is located on the inner side than in the prior art. Therefore, even when this portion bulges outward when the bulging portion 314 is formed, the gaps (Ga1 and Gb1) between the tubes of the double helix 310 can be made substantially equal.

It should be noted that how long the interval Dpa should be compared to the interval Dpb may be determined in consideration of the gap between the arc tubes to be set, the result of a manufacturing experiment, and the like.
Note that the forming jig used to form the double helix is not limited to the forming jig 400 according to the present embodiment. In short, the glass tube can be wound while keeping the gap between the first winding part and the second winding part wider than the gap between the winding parts located outside the first winding part. If it is, you may use the shaping | molding jig of another shape.
5). Others (1) Examples In the forming jig 400 described in the embodiment, the interval Dpa (see FIG. 7) is set to 12.5 mm, the interval Dpb is set to 14.5 mm, and the above (A) to (D). When the double spiral arc tube is manufactured through the above process, the innermost gap Ga (see FIG. 2) of the winding portion 130 is not narrower than the gap Gb, and both are approximately equal to about 3 mm. It was possible to be interval.

Further, the lamp provided with the double spiral arc tube has excellent characteristics such as a luminous flux 2310 (lm) and luminous efficiency 92.4 (lm / W) at a tube input 25W.
(2) Gap between Tubes The present invention is preferably applied to a method for manufacturing an arc tube in which the gap between the tubes in the winding portion 130 is particularly narrow (for example, 1.0 mm to 2.0 mm).

(3) Formation method of bulging part 314 (bulging part 121) The bulging part 314 is not restricted to the method described in embodiment. For example, after bending a glass tube, there is also a method in which the center portion is heated and applied to a mold, and high-pressure air is sent to partially inflate the center portion.
If this method is used, the boundary portion between the S-shaped portion in the vicinity of the center portion and the first winding portion will not swell to the outside in conjunction with it. It is difficult to adopt because it is thin and easy to break and it adds one process.

  According to the present invention, a method of manufacturing a double spiral arc tube in which the gap between the tubes in the winding portion is substantially constant, an arc tube having substantially the same gap between the tubes in the spiral portion manufactured by this manufacturing method, It becomes possible to provide a double spiral fluorescent lamp having an excellent external shape using this arc tube.

(A) Plan view of double spiral fluorescent lamp 1 according to the present embodiment (b) Front view (A) Partially broken plan view of arc tube 10 (b) Front view (A) The figure which shows the step which heats the glass tube 300 of the double helix formation process in which the softened glass tube is formed in a cone shape (double helix) in external appearance in the electric furnace 298. The figure which shows the step which hangs down the softened glass tube 300 on the top part of the shaping | molding jig 400. FIG. (C) The figure which similarly shows the step which winds the glass tube 300 around the shaping | molding jig 400. (d) The figure which shows the step which removes the glass tube 300 from the shaping | molding jig 400 similarly. (A) The figure which shows the step which installs a double helix in a deformation | transformation apparatus (b) The figure which shows the step which heats a double helix (c) The figure which shows the step which applies a pressure to a double helix and deform | transforms it (A) Plan view of forming jig 400 (b) Front view 6B is an enlarged view of the cross section along the straight line L4 in FIG. 6A in the region E of FIG. 6B. (A) Plan view of double spiral body 310 (b) Front view partially broken along line L5 in FIG. 8 (a) Plan view showing a conventional forming jig (A) Plan view of double helix 610 formed using conventional molding jig 500 (b) Front view partially broken along line L7 in FIG. 10 (a)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Double spiral fluorescent lamp 10 Arc tube 100 Arc tube main body 120 Center part 121 of arc tube body Swelling part 122 of arc tube S-shaped part 130 Winding part (spiral part) of arc tube
130a 1st winding part 130b 2nd winding part 300 Glass tube 301 Center part 310 of a glass tube Double spiral body 313 Winding part (vortex part) of a double spiral body
314 Double spiral bulge 400 Molding jigs 401a, 401b Locking portion 402 Guide path 403a First vertical wall 403b Second vertical walls 407a-407d Bottom wall 408 Locking path Dpa First vertical wall 403a and first Distance Dpb between the second vertical wall 403b located on the outer side and the nearest side of the vertical wall 403a Ga between the vertical walls on the outer side of the first vertical wall 403a The innermost first surrounding the S-shaped part 122 of the central portion 120 A gap Gb between the winding portion 130a and the second winding portion 130b that faces the first winding portion 130a and is positioned on the outer side of the first winding portion 130a. The winding is positioned on the outer side of the first winding portion 130a. Gap Ga1 between the winding portions Ga1 between the first winding portion 313a and the gap Gb1 between the second winding portion 313b Gap between the tubes further outside the first winding portion 313a

Claims (5)

In the state where the central portion of the softened glass tube is locked to the top of a substantially conical shaped forming jig, the glass tube is wound along the conical surface of the forming jig, and the outer shape is substantially conical. A double spiral light emission including a first step of forming a double helix having the shape and a second step of deforming the glass tube as the double helix into a flat shape until the tube axis is aligned on a substantially flat surface. A method of manufacturing a tube,
In the first step, an innermost first winding part that surrounds the S-shaped part of the central part of the double helix, and one outer side of the first winding part that faces the first winding part Wrapping the glass tube around the forming jig while keeping the gap with the second winding part located at a position wider than the gap between the winding parts located outside the first winding part ,
At the same time as the first step and / or after the first step, a bulging portion is formed in the central portion of the glass tube, and the gaps between the winding portions inside the end portion of the double helix are made substantially equal. A method of manufacturing a double spiral arc tube, characterized in that: An S-shaped locking path is formed at the top of the forming jig, and a double spiral guide path extending from both ends of the locking path is formed on the conical surface. The guide path is composed of a bottom wall and a vertical wall rising from the innermost part of the bottom wall, and in the first step, the glass tube is wound along the vertical wall of the guide path,
The distance between the innermost first vertical wall of the taxiway and the second vertical wall of the taxiway located outside and closest to the first vertical wall is the distance between the vertical walls outside the first vertical wall. The method of manufacturing a double spiral arc tube according to claim 1, characterized in that it is wider.   A double spiral arc tube manufactured by the arc tube manufacturing method according to claim 1 or 2.   The double spiral arc tube according to claim 3, wherein a gap between the tubes in the spiral portion of the double spiral arc tube is 1.0 mm to 2.0 mm.   A double spiral fluorescent lamp comprising the double spiral arc tube according to claim 3 or 4.

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