JP2006294302A - Manufacturing method for arc tube, arc tube, and fluorescent lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double-spiral arc tube that is good in outer appearance. <P>SOLUTION: A manufacturing method for the arc tube comprises: a first step of molding a double-spiral body whose outer appearance is generally conical in shape by bending a center portion of a softened glass tube into the shape of S and by winding portions of the glass tube that are closer to the ends thereof than the center portion around a cone face of a generally-cone-shaped molding tool; and a second step of deforming the glass tube as the double-spiral body into a nearly flat shape. On the surface of the molding tool, there is formed a double-spiral-shaped induction path 322 that continues in the shape of S. The induction path at the top of the molding tool has an S-shaped center placing part 325 to place the center portion of the glass tube thereon. At least a region of a bottom wall of the induction path extending from the center O of the center placing part 325 to the vicinity of a point at which the radius of curvature of a vertical wall of the center placing part 325 becomes minimum as viewed from above, including that point, is located in the same plane. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an arc tube, and more particularly, to a technique for manufacturing a glass tube having a substantially disk shape with a double spiral shape.

  In the lighting field, various compact fluorescent lamps (hereinafter simply referred to as fluorescent lamps) have been developed as energy-saving and resource-saving light sources. As an example, there has been proposed a fluorescent lamp (hereinafter referred to as a spiral fluorescent lamp) including an arc tube having a substantially disc shape in appearance and having a double spiral discharge path. FIG. 11A is a plan view of a double spiral glass tube constituting the arc tube of the spiral fluorescent lamp. A spiral fluorescent lamp having a glass tube 400 as a discharge path as shown in FIG. 11A is more compact than a conventional ring fluorescent lamp, and a preferable light distribution in which the irradiated surface is circular in terms of characteristics. Have a distribution.

In the arc tube body manufacturing process in the conventional method of manufacturing a spiral fluorescent lamp, first, the central portion of the softened glass tube is curved in an S shape along the weight surface of a substantially conical shaped forming jig, A portion on the end side with respect to the central portion is wound in a double spiral shape to produce a double spiral body having a substantially conical shape in appearance (for example, according to the methods disclosed in Patent Documents 1 and 2). Next, the double spiral glass tube 400 is manufactured by pressing the double spiral body under a temperature condition equal to or lower than the softening point of the glass tube to deform the glass tube into a substantially disk shape in appearance.
German patent 860675 German patent 871927

However, when the glass tube as a double helix is pressed and deformed into a substantially disk shape in appearance, the tube axis of the central portion 410 of the glass tube is substantially flush with the tube axis of the glass tube in the other region. It is extremely difficult to mold so.
That is, since the center portion of the double helix has an inclination with the center as the apex, when the double helix is pressed, a particularly large twist occurs in a portion where the radius of curvature of the center portion is minimum.

Therefore, when the central part is pressed to be flat, the arrangement of the glass tubes on the outer peripheral side is broken due to the twisting of the central part, and it is extremely difficult to arrange the glass tube in a desired shape. Therefore, in order to prevent the outer peripheral glass tube from being deformed, pressure can be applied only to a height at which the central portion is not twisted by pressing.
As a result, as shown in the front view of FIG. 11B, the central portion 410 of the glass tube 400 is in a floating state, and there is a problem that the appearance is not good.

  The present invention has been made in view of the above points, and a method of manufacturing a light-emitting tube having a good appearance with the tube axis of a spiral glass tube being on the same plane, and a light-emitting manufactured by the manufacturing method. An object of the present invention is to provide a fluorescent lamp comprising a tube and the arc tube.

  Therefore, the arc tube manufacturing method according to the present invention is such that a softened glass tube is curved in a central portion in an S shape, and a portion of the end portion side of the central portion is formed into a substantially conical shape. A first step of forming a double helix having a substantially conical shape in appearance, and a second step of deforming the glass tube as the double helix into a substantially flat shape. A method of manufacturing an arc tube, comprising: at least a radius of curvature of the central portion from the center of the central portion when the central portion is curved in an S shape in the first step. A region including a region and its vicinity is formed on the same plane.

According to the above manufacturing method, since the tube axis of the central portion of the double helix is formed on the same plane, the central portion having a small curvature radius is not twisted when pressed. Therefore, the tube axis of the glass tube can be arranged on the same plane without causing the glass tube on the outer peripheral side to lose its shape. Thereby, a spiral arc tube having a good appearance can be obtained.
In the above-described configuration, a guide path having a double spiral shape that is continuous with an S-shape is formed on the surface of the forming jig, and the guide path includes a bottom wall and an axis of the forming jig on the bottom wall. A vertical wall standing up from the side, and in the first step, the glass tube is wound along the vertical wall of the guide path, and the guide path at the top of the forming jig is the glass It has an S-shaped central mounting portion for mounting the central portion of the tube, and at least the radius of curvature of the vertical wall of the central mounting portion when viewed in plan from the center of the central mounting portion It is desirable that the bottom wall up to the vicinity including the portion where is minimum is on the same plane.

  By forming the double helix using the forming jig, the central portion including the portion having the minimum curvature radius from the center to the vicinity thereof is arranged on the same plane. Thereby, in the said 2nd process, even if it is a case where a double helix is pressed, since the center part with a small curvature radius does not twist, a glass tube of an outer peripheral side does not lose shape, but a tube axis Thus, a spiral arc tube having the same plane can be obtained.

  In addition, the guide path has a spiral wound mounting portion for mounting a portion closer to the end than the central portion of the glass tube, and the curved region of the central mounting portion For the first time, a curved region of the central mounting portion from the end of the central mounting portion is set so that the vertical wall of the winding mounting portion surrounding the first has a height at which at least the glass tube can be wound. It is desirable that the bottom wall of the wound mounting portion until it reaches the surrounding region has an inclination.

By giving a sufficient inclination to the bottom wall in the winding mounting portion, and by giving the vertical wall a sufficient height in the winding mounting portion surrounding the curved region of the central mounting portion for the first time, Since the glass tube can be wound around the vertical wall, the double helix can be easily formed.
Here, the said guide path has the spiral winding mounting part which mounts the part of the edge part side rather than the said center part of the said glass tube, and the said center mounting part is curving. In the region, it is desirable to form an auxiliary wall that rises from the side of the bottom wall opposite to the axis side of the forming jig.

By forming the auxiliary wall, it is possible to adjust the vertical wall to a height sufficient to wind the glass tube in the winding mounting portion that first surrounds the curved region of the central mounting portion. . Thereby, unwinding of the glass tube can be effectively prevented.
In addition, the guide path has a spiral wound mounting portion for mounting a portion closer to the end portion side than the central portion of the glass tube, and when the forming jig is viewed in plan view, It is desirable that the vertical wall of the central mounting portion where the vertical wall has the smallest radius of curvature draws an arc, and the vertical wall of the winding mounting portion draws a vortex.

A double helix having a good appearance can be formed by winding a glass tube around the vertical wall of the forming jig having such a configuration.
In order to achieve the above object, the arc tube according to the present invention is manufactured by any one of the above-described arc tube manufacturing methods. As a result, it is possible to provide a double spiral arc tube having a tube axis on the same plane and a good appearance.

  In order to achieve the above object, a fluorescent lamp according to the present invention includes the arc tube. As a result, it is possible to provide a double spiral fluorescent lamp having a good appearance with the tube axis of the arc tube being on the same plane.

Hereinafter, a fluorescent lamp manufacturing method and a fluorescent lamp according to an embodiment of the present invention will be described with reference to the drawings.
(Configuration of fluorescent lamp)
1A and 1B are diagrams showing a fluorescent lamp according to the present embodiment, in which FIG. 1A is a plan view and FIG. 1B is a front view.

  As shown in FIG. 1, the fluorescent lamp 1 according to the present embodiment is a spiral fluorescent lamp with a tube input 25W including an arc tube 10 and caps 20a and 20b attached to both ends of the arc tube 10. In addition, it is used for downlights directly attached to ceilings for store / house lighting, wall lights, and the like. The fluorescent lamp 1 is attached to a lamp (not shown) via the caps 20a and 20b, and is turned on by a high-frequency electronic ballast provided in the lamp.

2A and 2B are diagrams showing an arc tube of a fluorescent lamp, in which FIG. 2A is a partially broken plan view, and FIG. 2B is a front view. FIG. 3 is also a diagram showing an arc tube of a fluorescent lamp, in which FIG. 3 (a) is a plan view and FIG. 3 (b) is a front view.
As shown in FIG. 2, the arc tube 10 has a substantially disk shape in appearance and has a maximum outer diameter of 150 mm. The arc tube 10 includes an arc tube body 100 having a substantially disc shape in appearance, and electrodes 200a and 200b sealed at both ends 110a and 110b of the arc tube body 100. The outer diameter of the arc tube 10 is 9 mm, the inner diameter is 7.4 mm, the total length of the tube is 900 mm, the distance between the electrodes 200 is 800 mm, and the tube wall load is about 0.18 W / cm ² .

The arc tube 10 is not limited to the above-described configuration, but in order to make the fluorescent lamp 1 compact, it is preferable that the inner diameter of the arc tube 10 is in the range of 3 to 20 mm. The tube input is preferably in the range of 6-80W. For example, in the case of a fluorescent lamp with a tube input of 8 to 40 W, the tube outer diameter of the arc tube 10 is 8 to 14 mm, the tube inner diameter is 6 to 12 mm, and the tube wall load is 0.14 to 0.22 W / cm ^2. preferable. In the case of an optical watt fluorescent lamp with a tube input of 40 to 100 W, the tube inner diameter is preferably 12 to 16 mm.

The arc tube main body 100 is formed by, for example, a double spiral of a glass tube having a substantially circular cross section formed of barium / strontium silicate glass (soft glass having a softening point of 675 ° C.), as shown in FIG. The tube axis 101 of the arc tube main body 100 is swirling around the straight line A in a double spiral shape.
The tube axis 101 of the arc tube main body 100 is included in the same plane orthogonal to the straight line A.

  The arc tube main body 100 is formed by an S-shaped central portion 120, opposite end portions 110a and 110b facing each other across the central portion 120, and a portion formed between the central portion 120 and the opposite end portions 110a and 110b. It consists of a turning part 130. Specifically, as shown in FIG. 3 (a), the central portion 120 is a portion constituting a hatched area of the arc tube main body 100, and the end portions 110a and 110b are lattice patterns. The winding part 130 is a part that constitutes an area other than the central part 120 and the end parts 110a and 110b, that is, an area without a pattern.

  A portion placed on the top of a substantially cone-shaped forming jig 320 to be described later is a central portion 120, and this central portion 120 corresponds to the vicinity of the midpoint of the tube axis 101 of the arc tube main body 100. The central portion 120 has a bulging portion 121 having a tube outer diameter larger than that of the winding portion 130, and the bulging portion 121 becomes the coldest point when the fluorescent lamp 1 is lit. In the case of the fluorescent lamp 1 having an inner diameter of the arc tube 10 of 3 to 16 mm, if the temperature of the bulging portion 121 is designed to be 40 to 50 ° C. during lighting, a suitable lamp efficiency can be obtained. .

The winding part 130 turns about four times. In addition, the winding part 130 does not necessarily need to turn about 4 times, but it is preferable to turn about 2-5 times.
In a gap between adjacent tubes in at least the central portion 120 side region of the winding portion 130, a distance in a direction parallel to a plane including the tube axis 101 of the arc tube main body 100, that is, a direction substantially orthogonal to the straight line A. Gb2 is substantially uniform and is 2 mm. In order to make the fluorescent lamp 1 compact and reduce the color unevenness of the light emitting surface, the distance Gb2 is preferably in the range of 0.5 to 2 mm.

On the other hand, in the gap between adjacent tubes in the region near the ends 110a and 110b of the winding part 130, the gap is parallel to a plane parallel to the plane including the tube axis 101 of the arc tube main body 100, that is, substantially orthogonal to the straight line A. The distance in the direction becomes longer as it approaches the ends 110a and 110b.
The electrodes 200a and 200b include tungsten filament coils 201a and 201b and a pair of lead wires 202a and 202b. The electrodes 200a and 200b are hermetically sealed to the end portions 110a and 110b of the arc tube main body 100 in a state where the filament coils 201a and 201b are accommodated inside the arc tube main body 100 by a bead glass mount method.

In addition, at one end 110a of the arc tube main body 100, an exhaust tube 140 used for exhausting air in the arc tube 10 or sealing rare gas into the arc tube 10 is sealed in the tip portion. It is airtight.
A phosphor layer (not shown) is formed on the inner surface of the arc tube 10, and mercury 150 and a rare gas (not shown) are sealed inside the arc tube 10.

The phosphor layer is a rare earth phosphor composed of a red phosphor (Y ₂ O ₃ : Eu), a green phosphor (LaPO ₄ : Ce, Tb), and a blue phosphor (BaMg ₂ Al ₁₆ O ₂₇ : Eu, Mn). Is formed. The phosphor layer is not limited to the above configuration, and may be formed of a known rare earth phosphor.
5 mg of mercury 150 is sealed in the arc tube main body 100 in the form of mercury alone. The form of mercury 150 enclosed is not limited to the form of mercury alone, but may be, for example, zinc mercury or tin mercury or amalgam such as bismuth / indium mercury. That is, when the fluorescent lamp 1 is turned on, the vapor pressure characteristic of mercury in the arc tube 10 should be substantially the same as the vapor pressure characteristic when used alone.

The buffer gas is argon (Ar) and is sealed in the arc tube main body 100 so that the sealing pressure is about 400 Pa. The buffer 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 bases 20a and 20b include a pair of power supply terminal pins 21a and 21b connected to the lead wires 202a and 202b of the electrodes 200a and 200b. The bases 20a and 20b and the electrodes 200a and 200b are connected to the power supply terminal pins. They are electrically connected via 21a, 21b and lead wires 202a, 202b. The bases 20a and 20b are fixed to the end portions 110a and 110b of the arc tube 10 with an adhesive, for example.

(Fluorescent lamp manufacturing method)
Below, the manufacturing method of the fluorescent lamp 1 which concerns on embodiment of this invention is demonstrated. The manufacturing method of the fluorescent lamp 1 according to the embodiment of the present invention is characterized by the steps relating to the production of the arc tube main body 100, and the other steps are based on the prior art. Only the process according to the above will be described in detail, and the description of the other processes will be omitted or simplified.

1. Overall Flow First, the overall flow of the method for manufacturing the fluorescent lamp 1 will be briefly described.
4A and 4B are diagrams for explaining a manufacturing process of the arc tube main body. FIG. 4A is a diagram showing a glass tube used for manufacturing the arc tube main body, and FIG. 4B is a double spiral body. FIG. 4C is a view showing the arc tube main body.

5A and 5B are diagrams for explaining the forming process, in which FIG. 5A shows a step of attaching the forming jig to the driving device, and FIG. 5B is a step of winding the glass tube around the forming jig. FIG. 5C is a diagram showing a step of removing the glass tube from the forming jig.
6A and 6B are diagrams for explaining the deformation process, in which FIG. 6A shows a step of installing the double helix in the deformation device, and FIG. 6B shows a step of heating the double helix. FIG. 6C is a diagram showing a step of applying pressure to the double helix to deform it.

  In the production of the arc tube main body 100, first, the double helix 310 is produced from the glass tube 300 in the molding step as the first step. In the forming step, a straight tubular glass tube 300 as shown in FIG. 4A is prepared, the glass tube 300 is softened by heating, and wound around a conical surface of a forming jig 320 to be described later. A double helix 310 having a substantially conical shape in appearance and having a double helix tube axis as shown in FIG. In addition, the double helix 310 means the state which removed the removal parts 304a and 304b mentioned later from the glass tube after shaping | molding.

Next, a phosphor layer forming step is performed. In the phosphor layer forming step, the phosphor is applied to the inner surface of the double helix 310, and then the double helix 310 is heated to fire the phosphor.
Next, a deformation process as a second process is performed. In the deformation step, the double helix 310 is heated again, and is then deformed by applying pressure, so that the arc tube body 100 is deformed from a substantially conical shape in appearance to a generally disc shape in appearance as shown in FIG. Is molded. In addition, you may perform the baking of the fluorescent substance in a fluorescent substance layer formation process using the heat | fever of a deformation | transformation process. Thereby, improvement of production efficiency and reduction of manufacturing cost can be aimed at.

Next, an electrode sealing step is performed. In the electrode sealing step, the electrodes 200 a and 200 b are sealed to the end portions 110 a and 110 b of the arc tube main body 100.
The caps 20a and 20b are attached to the ends of the arc tube 10 thus manufactured, and the fluorescent lamp 1 is completed.
2. Molding process The molding process is described in detail below.

  The glass tube 300 used for producing the arc tube main body 100 has an outer diameter of 9 mm, an inner diameter of 7.4 mm, and a total length of 1500 mm. As shown in FIG. A central portion 301, winding portions 302 a and 302 b that become the winding portion 130 of the arc tube main body 100, end portions 303 a and 303 b that become the end portions 110 a and 110 b of the arc tube main body 100, and a double helix 310. It consists of removal sections 304a and 304b that are removed later.

7A and 7B are diagrams showing a forming jig, FIG. 7A is a plan view, and FIG. 7B is a front view. The glass tube 300 is formed into a double helix 310 having a substantially conical shape in appearance using a forming jig 320 as shown in FIG.
The forming jig 320 has a substantially conical shape in appearance, and a pair of locking portions 321a and 321b are provided at the top, and a guide path 322 is formed by recessing the weight surface on the weight surface. Yes. Needless to say, the forming jig 320 does not need to have a strict conical shape.

A straight line V shown in FIG. 7B is a line connecting the apex of the virtual cone and the center of the bottom surface when the forming jig 320 is assumed to be a complete cone, and the straight line V is the forming jig 320. Becomes the axis. The straight line W is a generatrix of the conical surface of the virtual cone. The angle α formed by the straight line V and the straight line W is, for example, about 53 °, but the angle α is not limited to about 53 °.
The conical surface of the forming jig in the present invention is the virtual cone when the weight surface does not actually exist because the guide path 322 is formed on the weight surface like the forming jig 320 according to the present embodiment. It means the cone surface of the body. When the guide path 322 or the like is not formed and a weight surface actually exists, it means the existing weight surface.

The locking portions 321a and 321b are for deforming and fixing the central portion 301 of the glass tube 300 in an S shape when the glass tube 300 is wound around the forming jig 320. The locking portions 321a and 321b The central portion 301 of the glass tube 300 is placed between 321b, and is deformed into an S shape by being wound along the locking portions 321a and 321b. The guide path 322 is formed on the weight surface of the forming jig 320 on the weight surface. It is formed along 300 winding paths. Specifically, it is formed in a double spiral shape with the straight line V as the rotation axis from the top to the bottom of the forming jig 320, with the locking portions 321a and 321b as a turning point.

  As shown in the enlarged view of FIG. 7B, the guide path 322 has a substantially L-shaped cross section, and the vertical rises from the bottom wall 324 and the straight wall V (axis of the forming jig) side of the bottom wall 324. Wall 323. The glass tube 300 is wound so that the glass tube 300 is brought into contact with the vertical wall 323. Note that the cross-sectional shape of the guide path 322 is not limited to a substantially L shape, and may be, for example, an arc shape having a curvature matched to the shape of the glass tube 300.

The guide path 322 may be formed by providing a convex portion on a part of the weight surface, in addition to forming a part of the weight surface by recessing. In addition, the guide path 322 does not necessarily have to be continuous over the whole, and there may be a discontinuous part in part, for example, intermittently with a certain interval.
The guide path 322 has a central placement portion 325 for placing the central portion of the glass tube 300 and a winding placement portion 326 for placing the winding portions 302 a and 302 b of the glass tube 300. The forming jig 320 is characterized in that the bottom wall of the central mounting portion 325 is on the same plane.

FIG. 8 is an enlarged view of the vicinity of the center placement portion 325 of the forming jig 320. In FIG. 8, a region delimited between the solid lines PP in the guide path 322 corresponds to the center placement portion 325. Further, a part of the guide path 322 other than the area delimited between the solid lines PP is used as the winding placement unit 326.
When viewed in plan, the vertical wall 330 of the central mounting portion 325 is linear, and the vertical wall 331 draws an arc having a radius r with the point R as the center. The radius r is about 2 mm, for example. Thereby, the center part 301 of the glass tube 300 wound around the vertical walls 330 and 331 of the center mounting part 325 is deformed into an S shape.

Further, the vertical wall 332 of the winding mounting portion 326 draws a vortex whose diameter gradually increases as the rotation angle increases around the point O that is the center of the central mounting portion 325. The arc drawn by the vertical wall 331 and the vortex drawn by the vertical wall 332 have a common tangent at the point S. A broken line Q is a common normal line between the arc and the vortex at the point S.
Further, an auxiliary wall 327 that rises from the bottom wall on the side opposite to the axial center side of the forming jig 320 is formed in the curved region of the central mounting portion 325. Thereby, the vertical wall of the winding mounting part 326 surrounding the curved area of the central mounting part 325 for the first time can be made high enough to wind the glass tube. Thereby, the unwinding of the glass tube at the time of shaping | molding a double helix can be prevented effectively.

9 is a cross-sectional view of the forming jig 320. FIG. 9A is a cross-sectional view taken along line AA in FIG. 7A, and FIG. 9B is FIG. FIG. 9C is a cross-sectional view taken along the line BB in FIG. 7A, and FIG. 9C is a cross-sectional view taken along the line CC in FIG.
As shown in FIG. 9A, the bottom wall of the central mounting portion 325 is on the same plane L. In addition, an auxiliary wall 327 is formed in the curved region of the central mounting portion 325.

As shown in FIG. 9B, the bottom wall of the central mounting portion 325 is on the same plane L up to a position around the locking portions 321a and 321b. As shown in FIG. 9C, the bottom wall of the central mounting portion 325 is on the plane L, and the bottom wall of the winding mounting portion 326 is on a plane M different from the plane L.
Returning to FIG. 9A, the vertical wall 332 a of the portion 326 a that first surrounds the curved region of the central mounting portion 325 in the winding mounting portion 326 is at least capable of winding the glass tube 300. Have It should be noted that the height at which the glass tube 300 can be wound is sufficient if it has a height corresponding to about 70% of the outer diameter of the glass tube 300. For that purpose, the bottom wall is sufficiently inclined in the portion of the wound mounting portion 326 from the end of the central mounting portion 325 to the portion that first surrounds the curved region of the central mounting portion 325. It is necessary to have Thereby, since it becomes possible to wind the glass tube 300 around the vertical wall 332a, the double helix 310 can be easily formed.

Next, a process of winding the glass tube 300 around the forming jig 320 will be described.
As shown in FIG. 5A, the forming jig 320 is attached to a rotating shaft 340 of a driving device (not shown). The axis (straight line V) of the forming jig 320 and the axis of the rotating shaft 340 coincide with each other, and these are collectively shown as a straight line V in FIG.
In producing the double helix 310, first, the glass tube 300 is heated and softened to, for example, about 780 ° C. in a heating furnace or the like. Then, the central portion 301 of the straight tubular glass tube 300 is disposed in a linear region of the central mounting portion 325. As shown in FIG. 5B, the driving device is driven in a state where both ends of the glass tube 300 are movably held, and the forming jig 320 is moved in the direction of the arrow C shown in FIG. Raise while rotating.

  As a result, the central portion 301 of the glass tube 300 is deformed into an S shape along the vertical wall 331 and is locked to the locking portions 321a and 321b. Then, the winding portions 302 a and 302 b of the glass tube 300 are wound up along the vertical wall 332 of the winding placement portion 326. In addition, when winding up, gas, such as air, nitrogen, and argon whose pressure is controlled, is blown into the glass tube 300 so that the glass tube 300 is not crushed and deformed.

After the winding around the forming jig 320 is completed and the temperature of the glass tube 300 is lowered and the glass is hardened, the hardened glass tube 300 is removed from the forming jig 320 as shown in FIG. And the removal parts 304a and 304b are removed from the removed glass tube 300, and the double helix 310 is completed.
FIG. 10 is a diagram showing a double helix, in which FIG. 10 (a) is a plan view and FIG. 10 (b) is a partially broken front view.

As shown in FIG. 10, the double helix 310 includes a central portion 312, both end portions 311 a and 311 b, and a winding portion 313 formed at a portion between the central portion 312 and both end portions 311 a and 311 b. .
The central portion 312 has a protruding portion 314 having a tube outer diameter larger than that of the winding portion 313, and the protruding portion 314 becomes the bulging portion 121 of the arc tube 10. The protrusion 314 is formed by locally softening the top of the double helix 310 and increasing the pressure in the double helix 310. The protrusion 314 may be formed immediately after the glass tube 300 is wound along the conical surface of the forming jig 320 or may be formed after being removed from the forming jig 320.

As shown in FIG. 10B, the tube axis of the central portion 312 of the double helix 310 is on the same plane N.
3. Deformation Step The deformation step will be described in detail below.
As shown in FIG. 6, the arc tube body 100 is produced from the double helix 310 using the deformation 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. Further, the movable plate 341 is formed with a through hole 345 in the approximate center of the movable plate 341 so that the protruding portion 314 of the double spiral body 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. 6A, the double spiral body 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 protruding 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 central portion 312 of the double helix 310.

Next, with the movable plate 341 in contact with the central portion 312 of the double helix 310, as shown in FIG. 6B, the temperature of the outer peripheral surface of the double helix 310 becomes about 620 ° C., for example. Heat like so. Note that 620 ° C. is a temperature at which the phosphor applied to the inner surface of the double helix 310 can be fired, and thereby the phosphor layer is fired on the inner surface of the double helix 310.
In addition, although heating temperature is not limited to 620 degreeC, it is preferable that it is set lower than the softening point (675 degreeC) 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 ° C., 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. At this time, the double spiral body 310 descends in order from the outer peripheral portion.
Here, conventionally, since the tube axis of the central part of the double helix is not arranged on the same plane and has an inclination with the center of the center as the apex, the curvature is reduced when pressing the double helix. A particularly large twist occurred in a portion having the smallest radius.

Therefore, when the movable plate 341 is lowered to a certain height, the movable plate 341 is supported by the twisting force acting on the central portion, and the movable plate 341 reaches the regulating member 344 having a height substantially equal to the outer diameter of the glass tube. There were many cases that did not descend.
Here, even if pressure is further applied to the movable plate 341 to flatten the central portion, the arrangement of the glass tubes on the outer peripheral side collapses due to the central portion being twisted, and the arc tube body is desired. It was almost impossible to adjust the shape.

On the other hand, in the present embodiment, since the tube axis of the central portion 312 is on the same plane in the double helix 310, when the double helix 310 is pressed by the movable plate 341, the twist is not generated in the central portion 312. Almost does not occur.
Therefore, as shown in FIG. 6C, the movable plate 341 is lowered by its own weight until it comes into contact with the regulating member 344. Thereby, the arc tube main body 100 of the spiral shape with the tube axis being on the same plane and having a good appearance can be formed.

Here, a description will be given of at least in which region of the central portion 312 of the double helix 310 it is sufficient that the tube axes are in the same plane.
Conventionally, when a double helix is pressed, a particularly large twist is presumed to be a portion having a minimum radius of curvature in a central portion curved in an S shape.
Therefore, when pressing the double helix 310, in order not to cause a large twist in the central portion 312, at least from the center of the central portion 312 to the vicinity including the portion of the central portion 312 where the curvature is minimum. It is considered that the tube axis needs to be on the same plane in the above areas.

Therefore, when the central portion 301 of the glass tube 300 is curved in an S shape, at least the center from the S shape to the vicinity including the portion having the minimum curvature is formed on the same plane. is required.
When the central portion 301 of the glass tube 300 is bent into an S shape using the forming jig 320, the portion having the smallest radius of curvature is a portion wound around the vertical wall 331 as shown in FIG. Therefore, the forming jig 320 for winding the glass tube 300 includes at least a portion where the radius of curvature of the vertical wall of the central mounting portion 325 is minimum when viewed in plan from the center O of the central mounting portion 325. That is, in the region including the vertical wall 331 up to the vicinity thereof (the region wider than the region indicated by the broken line Q-Q in the drawing), the bottom wall may be on the same plane.

When the central portion 301 of the glass tube 300 is curved in an S shape, all the portions that are S-shaped should be formed on the same plane in order to bend so that the radius of curvature is equal at any portion. Thus, the tube axes may be arranged on the same plane.
<Modification>
As described above, the present invention has been described based on the embodiments. However, the content of the present invention is not limited to the specific examples shown in the above-described embodiments. For example, the following modifications are possible. Can think.

  In the above description, the case where the central portion 301 of the glass tube 300 is bent in an S shape has been described, but the shape to be bent is not limited to this, and for example, the central portion 301 of the glass tube 300 is bent in an inverted S shape. You may let them. Even in this case, when the central portion 301 of the glass tube 300 is curved in an inverted S shape, at least from the center of the central portion 301, including the portion having the smallest radius of curvature in the central portion 301. By forming the region up to the vicinity on the same plane, it is possible to obtain a spiral-shaped arc tube main body in which the tube axis is arranged on the same plane and the appearance is good.

  The present invention can be widely applied when manufacturing a luminous tube having a good appearance with the tube axis of a spiral glass tube being on the same plane. In addition, the present invention can provide a light emitting tube having a good appearance and a tube using a spiral glass tube on the same plane, and a lamp using this light emitting tube. Extremely expensive.

It is a figure which shows the fluorescent lamp which concerns on one Embodiment of this invention, Comprising: (a) is a top view, (b) is a front view. It is a figure which shows an arc tube, Comprising: (a) is a partially broken plan view, (b) is a front view It is a figure which shows an arc tube, Comprising: (a) is a top view, (b) is a front view FIGS. 4A and 4B are diagrams for explaining the arc tube body manufacturing process, in which FIG. 4A shows a glass tube used for manufacturing the arc tube body, and FIG. 4B shows a double helix. 4 (c) is a diagram showing the arc tube body. FIG. 5A is a diagram for explaining a molding process, FIG. 5A is a diagram illustrating a step of attaching a molding jig to a driving device, and FIG. 5B is a diagram illustrating a step of winding a glass tube around the molding jig; FIG.5 (c) is a figure which shows the step which removes a glass tube from a shaping | molding jig. 6A and 6B are diagrams for explaining the deformation process, in which FIG. 6A shows a step of installing the intermediate body in the deformation device, FIG. 6B shows a step of heating the intermediate body, and FIG. c) is a diagram showing a step of applying pressure to the intermediate body to deform it. It is a figure which shows a shaping | molding jig, Comprising: Fig.7 (a) is a top view, FIG.7 (b) is a front view. Enlarged view showing the top of the forming jig It is sectional drawing of a shaping | molding jig, Comprising: Fig.10 (a) is AA arrow sectional drawing of Fig.7 (a), FIG.10 (b) is BB arrow sectional drawing of FIG. 10 (b) is a cross-sectional view taken along the line CC of 7 (a). It is a figure which shows a double helix, Comprising: Fig.10 (a) is a top view, FIG.10 (b) is a partially broken front view It is a figure of the spiral glass tube which comprises the arc tube of the conventional spiral fluorescent lamp, Comprising: Fig.11 (a) is a top view, FIG.11 (b) is a front view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fluorescent lamp 10 Arc tube 100 Arc tube main body 300 Glass tube 310 Double helix 320 Molding jig 322 Guide path 323 Vertical wall 324 Bottom wall 325 Central mounting part 326 winding mounting part

Claims (7)

The softened glass tube is curved in an S-shape at the center, and the portion closer to the end than the center is wound along the weight surface of a substantially cone-shaped forming jig. A method for manufacturing an arc tube comprising: a first step of forming a double helix having a conical shape; and a second step of deforming the glass tube as the double helix into a substantially flat shape,
In the first step, when the central portion is curved in an S shape, at least a region from the center of the central portion to the vicinity thereof including a portion having a minimum curvature radius in the central portion is included. A method of manufacturing an arc tube, wherein the arc tube is formed on the same plane. On the surface of the forming jig, a double spiral spiral guide path is formed,
The guide path includes a bottom wall and a vertical wall that rises from the axial center side of the forming jig of the bottom wall, and the glass tube is wound along the vertical wall of the guide path in the first step. And
The guide path at the top of the forming jig has an S-shaped central mounting portion for mounting the central portion of the glass tube,
At least the bottom wall up to and including the portion where the radius of curvature of the vertical wall of the central mounting portion is minimized when viewed in plan from the center of the central mounting portion is on the same plane. 2. A method of manufacturing an arc tube according to claim 1, wherein The guide path has a spiral wound mounting portion for mounting a portion closer to the end side than the central portion of the glass tube,
The vertical wall of the winding mounting part that surrounds the curved region of the central mounting part for the first time has a height at which the glass tube can be wound at least from the end of the central mounting part to the center. The method of manufacturing an arc tube according to claim 2, wherein the bottom wall of the wound mounting portion until it reaches a region surrounding the curved region of the mounting portion for the first time has an inclination. The guide path has a spiral winding placement part for placing a part closer to the end side than the central part of the glass tube,
The arc tube according to claim 2, wherein an auxiliary wall that rises from a side of the bottom wall opposite to the axis side of the forming jig is formed in the curved region of the central mounting portion. Manufacturing method. The guide path has a spiral winding placement part for placing a part closer to the end side than the central part of the glass tube,
When the forming jig is viewed in plan, the vertical wall of the central mounting portion where the vertical wall has the smallest radius of curvature draws an arc, and the vertical wall of the winding mounting portion draws a vortex. The method for manufacturing an arc tube according to any one of claims 2 to 4, wherein:   An arc tube manufactured by the method for manufacturing an arc tube according to any one of claims 1 to 5.   A fluorescent lamp comprising the arc tube according to claim 6.

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