JP4287330B2 - Manufacturing method of arc tube - Google Patents

Description

  The present invention relates to a method of manufacturing an arc tube made of bent glass having a phosphor layer coated and fired on an inner peripheral surface.

An annular fluorescent lamp using an annular arc tube is widely known as a low-pressure mercury discharge lamp used for general illumination. In recent years, there has been a strong demand for miniaturization of the annular fluorescent lamp. This is because by reducing the size of the annular fluorescent lamp, not only the annular fluorescent lamp but also the lighting device can be reduced in size, space and resource.
For example, the glass tube constituting the arc tube has a central axis within one plane and around a predetermined axis from one end of the glass tube. There is one formed in a shape that turns away from the predetermined axis as it moves to the end (this shape is referred to as “flat single helix shape”) (Patent Document 1).

Thus, by making the glass tube into a flat single spiral shape, the glass tube can be arranged in the space inside the conventional ring shape, and the maximum outside of the arc tube is compared with the conventional arc tube. The diameter can be reduced.
The flat single spiral arc tube is manufactured by forming a conical shape by winding a softened glass tube along the outer peripheral surface of a conical forming jig, and forming the conical shape. The glass is heated to a temperature higher than its softening temperature and deformed into a flat single helix using the weight of the glass tube, and the flat single helix glass tube is fluorescent. It is manufactured through a firing process in which a body suspension is applied and then fired into a phosphor layer. In addition, the process of attaching the electrode to the glass tube and the process of enclosing mercury / buffer gas inside the glass tube are performed after the firing process.
JP-A-9-92154

  In the conventional arc tube manufacturing method, the phosphor that has flowed into the flat single spiral glass tube on the mass production base does not flow out smoothly, and a local phosphor pool is formed in the tube. The problem is that efficiency and quality are poor, and it is necessary to heat the glass tube in each of the forming process, deformation process and firing process, and it takes time to raise and lower the temperature of the glass tube, resulting in poor production efficiency and heating. There is a problem of high cost.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of manufacturing an arc tube that can improve production efficiency, improve quality, and reduce costs.

In order to achieve the above object, a method of manufacturing an arc tube according to the present invention includes a cone shape in which a glass tube is heated to a temperature equal to or higher than a softening point and wound along a cone surface of a cone-shaped forming jig. And forming the cone-shaped glass tube at a temperature lower than the softening point temperature and higher than a temperature at which the glass tube can be deformed, so that at least a part of the axis of the glass tube has the cone shape. A deformation step of deforming into a flat shape included in a plane substantially orthogonal to the central axis of the glass tube, and an inner peripheral surface of the glass tube formed in the cone shape between the formation step and the deformation step coating process there for applying a fluorescent material is, and the firing treatment of the coated phosphor is characterized in that performed using the heat at the time of heating in the deformation process. According to this method, since the shape of the glass tube to which the phosphor is applied is a cone, the phosphor that has flowed into the glass tube flows out smoothly.

The “conical shape” here is not limited to the double spiral shape described later, and is a concept including a single spiral shape, for example. Furthermore, for example, a shape in which an intermediate portion of one glass tube has a double spiral shape and a portion near the end of the glass tube linearly extends in a predetermined direction is included.
Further, the "cone shape", Ru concept der including conical, polygonal shape, an elliptical cone shape or the like.

Also, it is characterized by performing the firing process of the coated phosphor using heat during heating in the deformation process.
As used herein, “using heat during heating” means that the phosphor is fired by using heat to heat the glass tube in order to change the shape of the glass tube from a cone shape to a flat shape. It does not matter whether there is a lot of heat used or less. That is, if the firing process of the phosphor is started while the heat heated in the deformation process remains in the glass tube, the heat at the time of heating in the deformation process is used.

  In the forming step, the central portion of the glass tube is hooked on the top of the cone-shaped forming jig, and the portion from the central portion of the hooked glass tube to the end is halfway on the cone. It is characterized in that it is formed in a double spiral cone shape wound along the cone surface of the body-shaped forming jig.

The manufacturing method of the arc tube according to the present invention includes an application step of applying a phosphor to the inner peripheral surface of the glass tube formed in the cone shape between the forming step and the deformation step. As a result, the phosphor that has flowed into the glass tube flows out smoothly, and a local phosphor reservoir is not formed in the glass tube, so that the time production efficiency and quality are improved.
Further, the heat of the deformation process is used for the baking treatment of the applied phosphor. As a result, it is possible to reduce costs such as utility costs when heating to the firing temperature of the phosphor, and further, heating equipment becomes unnecessary, and costs such as equipment introduction costs can be reduced. Furthermore, for example, the heating time can be shortened and the production efficiency can be improved as compared with the case where the glass tube is heated from room temperature.

  In particular, when the baking treatment is performed substantially simultaneously in the deformation step, the heat heated to deform the glass tube can be used effectively, and the above effect is enhanced.

Embodiments of a fluorescent lamp using an arc tube according to the present invention will be described below with reference to the drawings.
1. FIG. 1 is a perspective view of a fluorescent lamp according to an embodiment. 2 is a view of the fluorescent lamp as viewed from below in FIG. 1, and FIG. 3 is a view of the fluorescent lamp as viewed from the X direction in FIG. In FIGS. 2 and 3, a part of the arc tube and the holder are notched so that the inside of the arc tube and the holder can be seen. 1 is the irradiation side, and viewing from the lower side in FIG. 1 is also referred to as “viewing from the irradiation surface side”.

As shown in FIGS. 1 to 3, the fluorescent lamp 10 includes an arc tube 100 having a single discharge path therein, and a holder 200 that holds the arc tube 100. As will be described later, a power supply base 250 is attached to the holder 200.
(1) Regarding the arc tube As shown in FIGS. 1 to 3, the arc tube 100 includes an arc tube body 110 formed by bending a single, for example, straight tubular glass tube into a double spiral shape, and an arc tube. And electrodes 140 sealed at both ends 114 and 116 of the main body 110.

The both end portions 114 and 116 of the arc tube main body 110 are portions corresponding to both end portions of the glass tube constituting the arc tube main body 110, and the ends of the internal discharge path when this portion is used as the arc tube 100. It corresponds to the part.
In FIG. 3, the description of the electrode at the end portion 116 of the arc tube main body 110 is omitted for convenience of drawing, but an electrode having the same structure as the electrode 140 is also sealed at the end portion 116.

Inside the arc tube main body 110, in addition to mercury (for example, 5 mg), an argon-neon mixed gas (for example, a ratio of argon gas to neon gas is 75:25 as a buffer gas, and a sealing pressure is 400 ( Pa).) Is enclosed.
The mixing ratio of argon gas and neon gas in the buffer gas is not limited to the above ratio, and the buffer gas may be composed of argon gas alone or neon gas alone.

  The form of mercury enclosed in the arc tube main body 110 may be a single form, or may be an amalgam form such as zinc mercury, tin mercury, or bismuth / indium mercury. In other words, the form of mercury is not particularly limited as long as the vapor pressure characteristic of mercury in the arc tube 100 exhibits substantially the same characteristic as that of mercury alone when the fluorescent lamp 10 is turned on. Not.

As shown in FIG. 2, for example, a phosphor layer 160 is formed on the inner peripheral surface of the arc tube main body 110. The phosphor layer 160 is obtained by firing a known rare earth phosphor. Here, this phosphor has three types of red, green, and blue light emission, and includes, for example, Y ₂ O ₃ : Eu, LaPO ₄ : Ce, Tb, and BaMg ₂ Al ₁₆ O ₂₇ : Eu, Mn phosphor. It is.
As shown in FIG. 2, the electrode 140 is of a so-called bead glass mount type, and includes a filament coil electrode 142 made of tungsten, a pair of lead wires 146 and 148 that support the filament coil electrode 142, It consists of a bead glass 144 that fixes and supports a pair of lead wires 146 and 148.

It is a part of the lead wires 146 and 148 that is sealed to the end portion 114 (, 116) of the arc tube body 110 in the electrode 140, and specifically, extends from the bead glass 144 to the side opposite to the coil electrode 142. It is the part that has been put out.
Note that the exhaust pipe 150 is sealed together with the electrode 140 at one end portion (here, the end portion 114) of the arc tube main body 110. The exhaust pipe 150 is used when the arc tube body 110 is exhausted or a buffer gas is sealed after the electrode 140 or the like is sealed.

As shown in FIGS. 1 to 3, the arc tube main body 110 includes two swiveling portions 122 and 124 that swivel around a predetermined axis A, which will be described later, and an intermediate portion that is connected between the swiveling portions 122 and 124. 120.
The axis of the glass tube 112 that constitutes the intermediate part 120 and the swivel parts 122 and 124 is substantially in one plane substantially orthogonal to the predetermined axis A, and the swivel parts 122 and 124 have both end parts 114 and 124 from the intermediate part 120 side. It turns so that it may leave | separate from the predetermined axis A as it moves to 116 side.

That is, the arc tube main body 110 has two swivel portions 122 and 124, and the axis of the glass tube 112 constituting the swivel portions 122 and 124 is in a substantially single plane. It is called a double helix shape.
As shown in FIGS. 2 and 3, at the position where the predetermined axis A in the arc tube body 110 passes, that is, at the approximate center of the intermediate portion 120 of the glass tube 112, A bulging portion 126 bulging on the opposite side is formed.

For example, barium strontium silicate glass (which is also lead-free glass and soft glass) is used for the glass tube 112, and the softening point of this glass material is 675 (° C.). The cross-sectional shape of the glass tube 112 is substantially circular, for example.
The cross-sectional shape of the glass tube 112 is not limited to a circular shape, and may be, for example, a substantially elliptical shape or a polygonal shape. However, the arc tube main body 110 is formed into a flat double spiral shape by curving the softened glass tube 112, and the cross-sectional shape of the glass tube after the formation is not a perfect circle but slightly deformed It becomes.

As shown in FIG. 2, when the arc tube main body 110 is viewed from the irradiation surface side, the swivel unit 122 and the swivel unit 124 adjacent to a direction orthogonal to the predetermined axis A (hereinafter, this direction is referred to as “radial direction”) There is a gap between them.
The gap between the adjacent swirling portions 122 and 124 connects the centers in the cross section of the swiveling portions 122 and 124 because the cross section of the glass tube 112 constituting the swirling portions 122 and 124 has a circular shape. The gap between the two on the line segment is minimized, and this smallest gap is represented as a gap Ga.

  The gap between the adjacent swiveling portions 122 and 124 is larger in the portion near the ends 114 and 116 of the arc tube main body 110 than the gap between the other swiveling portions 122 and 124. This is for attaching the arc tube 100 to the holder 200, and the “gap Ga” is a portion close to the end portions 114, 116 of the arc tube main body 110 (for example, from the end portions 114, 116 to the intermediate portion 120 side). It indicates a gap in a range excluding a portion up to about 45 degrees along each turning portion 122, 124).

  Here, after the phosphor layer 160 is formed on the inner surface of the arc tube main body 110, the electrode 140 is sealed, and the arc tube body 110 is filled with a buffer gas or the like to complete the arc tube 100. In the following description, when using the “arc tube 100”, the end portions 114 and 116 of the arc tube main body 110 and the portions corresponding to the intermediate portion 120 and the reference numerals are used as they are. 114, 116, intermediate portion 120, and the like. The radial direction of the arc tube main body 110 and the predetermined axis A are used as they are in the radial direction and the predetermined axis A when the arc tube 100 is described.

(2) Holder As shown in FIGS. 1 to 3, the holder 200 includes a holding member 210 for holding the ends 114 and 116 of the arc tube 100 and a base 250 for supplying power to the arc tube 100. It consists of a base attachment member 230 attached. The arc tube 100 is attached to the holder 200 so that the bulging portion 126 side is the front side (irradiation surface).

As shown in FIGS. 1 and 3, the base 250 is a type including four power supply connection pins 250 a, 250 b, 250 c, and 250 d. Therefore, the fluorescent lamp 10 is attached to the lamp through the base 250 and is lit by an electronic ballast dedicated to high frequency provided on the lamp side.
The holding member 210 includes a base 212 that is long in the direction connecting the ends 114 and 116 of the arc tube 100, and raised portions 214 and 216 formed at both ends in the longitudinal direction of the base 212. In the raised portions 214 and 216, insertion holes for inserting the end portions 114 and 116 of the arc tube 100 are formed.

As a result, the end portions 114 and 116 of the arc tube 100 are supported by abutting against the wall surface constituting the insertion hole when inserted into the insertion hole, and the lead wires 146 and 146 led out from the end portions 114 and 116 are supported. As shown in FIG. 3, 148 is guided to the back side of the base 212 through the inside of the insertion hole.
As shown in FIG. 3, a space portion 222 is provided inside the holding member 210 so that a pair of lead wires 146 and 148 led out from the end portions 114 and 116 of the arc tube 100 can be connected to the base 250 side. The base attaching member 230 is attached to the holding member 210 so as to close the space 222 from above. The base attaching member 230 is fixed to the holding member 210 with an adhesive, for example.
2. Specific Configuration of Fluorescent Lamp The specific configuration of the fluorescent lamp according to the present invention will be described. The glass tube 112 used for the arc tube body 110 has an outer diameter D1 of 9.0 (mm) and an inner diameter D2 of 7.4 (mm) (see FIG. 2).

The arc tube main body 110 swivels around the predetermined axis A about 2 times to about 5 times, for example, about 4 times in total, including the two swivel portions 122 and 124. As shown in FIG. 2, the arc tube 100 has a length L1 in the direction connecting the end portions 114 and 116 of 120 (mm), and a length L2 in the direction orthogonal to the line segment connecting the end portions 114 and 116. 110 (mm).
The gap Ga between the glass tubes 112 adjacent to each other in the radial direction of the arc tube 100 is about 1.5 (mm), and the overall height including the bulging portion 126 in the fluorescent lamp 10 is 10 (mm) to 11 (mm). The total length of the glass tube 112 is 950 (mm), and the distance between the electrodes inside the arc tube 100 is 920 (mm). The gap Ga between the glass tubes 112 adjacent to each other in the radial direction of the arc tube 100 is 1.5 (mm) here, but about 1 (mm) to 10 (mm) is considered appropriate as a product. It is done.

In the fluorescent lamp 10 using the arc tube 100, the lamp input is set to 25 (W), and the tube wall load of the arc tube 100 at this time is 1.58 (W / cm ² ). During lighting, the bulging portion 126 of the arc tube 100 (the arc tube main body 110 constituting the arc tube 100) is the coldest spot, and the temperature is set to 47 (° C.) to 52 (° C.). Yes. In this temperature range, there is a peak value at which the lamp efficiency reaches the maximum value, and in this temperature range, there is not much difference from the maximum value of the lamp efficiency.
3. Manufacturing method of arc tube The manufacturing method of the arc tube 100 of the said structure is demonstrated using drawing.

FIG. 4 is a diagram for explaining a process of manufacturing the arc tube main body.
In the arc tube body manufacturing method described here, the arc tube body 110 described in the above specific configuration is manufactured. First, the flow of the manufacturing process will be briefly described, and then each process will be described.
First, as shown in FIG. 4A, a straight tubular glass tube 510 is prepared, the glass tube 510 is softened by heating, and the axis of the forming jig is formed along the conical surface of the forming jig described later. An intermediate body 540 is formed by winding a core (this axial center corresponds to a center axis A1 of an intermediate body described later and a predetermined axis A). As shown in FIG. 4 (b), the intermediate body 540 has an outer shape when the rolled glass tube 510 is viewed from the radial direction, which corresponds to a substantially conical shape (the “conical shape” of the present invention). )

  Next, unnecessary portions on the end side of the glass tube in the obtained intermediate body 540 are removed, and then a suspension containing phosphor is applied to the inner peripheral surface of the glass tube 554 constituting the intermediate body 540. Then, it is dried and the phosphor is applied to the inner peripheral surface of the glass tube 554. Finally, the glass tube 554 is heated to perform the firing process of the applied phosphor. In this case, the final coated phosphor may be baked by using the heating in the next deformation step, thereby improving the production efficiency and reducing the manufacturing cost.

Then, the intermediate 540 is heated again, and the intermediate 540 is compressed and deformed in the extending direction of the central axis A1 (hereinafter, also simply referred to as “central axial direction”). Thereby, the arc tube body 110 having a flat double spiral shape is manufactured.
Thereafter, an electrode sealing process for sealing the electrodes 140 and 140 to the ends 114 and 116 of the arc tube main body 110, a sealing process for sealing mercury and a buffer gas inside, and the like are performed. Since the same technique is used, the description here is omitted.

Hereinafter, a forming process for forming a cone-shaped intermediate body, a coating process for applying the phosphor, a deformation process for deforming the intermediate body into a flat shape, and a deformation / firing process for combining the firing process for firing the phosphor Each will be described.
(1) One example of forming process for forming intermediate Regarding Glass Tube First, the glass tube 510 will be described. As shown in FIG. 4A, the glass tube 510 includes an intermediate portion 510a and two scheduled winding portions 510b and 510c sandwiching the intermediate portion 510a in the longitudinal direction. When the intermediate body 540 is formed from the glass tube 510, the range including at least the intermediate portion 510a and the two scheduled winding portions 510b and 510c is softened by heating. The glass tube 510 has a substantially circular cross-sectional shape. In this example, the outer diameter is 9.5 (mm), the inner diameter is 8.0 (mm), and the total length is 1500 (mm).

B. About the intermediate body The intermediate body 540 is formed by bending the intermediate portion 510a of the glass tube 510 and the planned winding portions 510b and 510c.
5A is a partially cutaway side view of the intermediate body of FIG. 4B, and FIG. 5B is a view when the intermediate body is viewed from the Y direction in FIG. 5A. is there.

As shown in FIGS. 5A and 5B, the intermediate body 540 is formed by winding the two scheduled winding portions 510 b and 510 c of the glass tube 510 around the axis B of the forming jig 590. It has two winding parts 548 and 550 and an intermediate part 542 that is sandwiched between the two winding parts 548 and 550 and connects them.
Specifically, the winding portions 548 and 550 are wound along the conical surface of the forming jig 590 (the “conical surface” of the present invention). Being done. As the winding portions 548 and 550 move from the intermediate portion 542 side to the end portion side of the glass tube 510, the winding portions 548 and 550 are separated from the intermediate portion 542 on the central axis A1 (downward in FIG. 5A) and the central axis. It also has a double spiral shape that revolves around the central axis A1 so as to be separated from A1 in the radial direction. For this reason, the external shape of the intermediate body 540 is substantially conical. The angle between the cone-shaped bus and the axis B of the cone-shaped main body 591 is approximately 53 degrees, and is indicated by “α” in FIG.

The positional relationship between the two winding portions 548 and 550 is when the intermediate body 540 is viewed from the central axis direction (this is when viewed from the Y direction in FIG. 5, and the figure at that time is FIG. The minimum gap L3 formed between the winding portions 548 and 550 adjacent in the radial direction is 1.0 (mm) to 1.5 (mm).
Further, when the intermediate body 540 is viewed from a direction orthogonal to the central axis A1 (that is, (a) in FIG. 5), a part of the winding parts 548 and 550 adjacent to the central axis direction is in that direction. This overlapping portion L4 is D1 / 2 or less.

C. Regarding the jig for forming the intermediate body The intermediate body 540 having the above-described shape is formed by locking the intermediate portion 510a of the softened glass tube 510 with the locking portions 593 and 594 of the forming jig 590, and then It is formed by winding the scheduled winding portions 510 b and 510 c around the conical surface of the forming jig 590.
FIG. 6 is a diagram illustrating a process of forming the intermediate body, and FIG. 6A is a diagram illustrating a state of the forming jig before winding the glass tube.

  First, as shown in FIG. 6A, the forming jig 590 includes a main body portion 591 having a conical surface (conical shape), and a columnar attachment portion 592 attached to a driving device (not shown). The softened glass tube 510 is wound around the conical surface of the main body 591. Note that the axis of the main body 591 and the axis of the mounting portion 592 coincide with each other, and in FIG. 6A, these are collectively indicated by the symbol “B” as the axis of the forming jig 590. . A direction perpendicular to the axis B of the forming jig 590 is referred to as a “radial direction”.

A pair of locking portions 593 and 594 for locking the intermediate portion 510 a of the glass tube 510 face each other at the top of the main body portion 591, and the main body portion 591 has a conical surface. Recessed portions 595 and 596 for receiving the scheduled winding portions 510b and 510c of the glass tube 510 wound around 591 are formed in a double spiral shape continuous from the top to the bottom.
The pair of locking portions 593 and 594 protrude from the top of the main body portion 591 in a direction parallel to the axis B of the forming jig 590 with a space in which the glass tube 510 is inserted therebetween. The locking portions 593 and 594 are constituted by, for example, pillars such as pins.

The cross section of the recessed portions 595 and 596 has a step shape along the outer peripheral edge of the main body portion 591, and the corner portions of the recessed portions 595 and 596 are arc surfaces having the same curvature as the outer periphery of the glass tube 510. ing.
Here, the outer peripheral surface of the main body portion 591 is a step shape and not a conical surface in terms of an accurate shape, but a surface formed by connecting the corners of the step (indicated by a bus B1 in FIG. 6). Since it becomes a conical surface and the appearance of the glass tube 510 wound around the forming jig 590 has a substantially conical shape, it is considered as a virtual conical surface.

  Next, a specific configuration of the forming jig 590 will be described. The forming jig 590 described here also has the above 3. (1) For intermediate 540 described in the section about B intermediate. The step H of the recesses 595 and 596 formed on the outer periphery of the main body 591 is about 0.85 times the outer diameter D1 of the glass tube 510 to be wound. In addition, the overhang W of the stepped depressions 595 and 596 is about 1.5 (mm) larger than the outer diameter D1 of the glass tube 510 to be wound. The angle β between the generatrix B1 and the axis B of the main body 591 is about 53 degrees.

Then, the formation process of an intermediate body is demonstrated.
First, the mounting portion 592 of the forming jig 590 is attached to a driving device (not shown). As shown in FIG. 6B, this driving device has a function of moving the forming jig 590 on the axis B in the G direction while rotating the axis B around the axis B in the F direction. ing.
Next, the intermediate portion (including at least the intermediate portion 510a and the scheduled winding portions 510b and 510c) of the glass tube 510 is heated and softened in a heating furnace or the like so as to be, for example, 800 ± 20 (° C.).

The substantial center of the intermediate portion 510a of the softened glass tube 510 is inserted between the engaging portions 593 and 594 of the forming jig 590, and both ends of the glass tube 510 are moved as shown in FIG. In a state where it is held as possible, the forming jig 590 is rotated around the axis B in the F direction and moved in the G direction.
As a result, the intermediate portion 510a of the glass tube 510 is locked to the locking portions 593, 594, and the two scheduled winding portions 510b, 510c are wound along the recessed portions 595, 596 (conical surfaces) of the main body portion 591. .

The amount of movement of the forming jig 590 that moves in the G direction during one rotation is the level difference H of each of the recesses 595 and 596 formed on the main body 591, that is, twice the level difference H. At this time, a pressure-controlled gas such as nitrogen or argon is blown into the glass tube 510 so that the wound glass tube 510 has a circular cross section.
Then, when the winding of the glass tube 510 around the forming jig 590 is completed and the temperature of the glass tube 510 is lowered and the glass tube 510 is cured, the cured glass tube 515 is removed as shown in FIG. Remove from the forming jig 590.

In addition, the code | symbol of the glass tube in the state in which the external shape was formed in the cone shape is used as “515” in order to distinguish from the glass tube 510 before and around the forming jig 590.
The unnecessary portion of the glass tube 515 removed from the forming jig 590 is cut, whereby the formation of the intermediate 540 is completed.

  A protrusion 552 (see FIG. 7A) for the bulging portion 126 of the arc tube 100 is formed on the top of the intermediate body 540. The protrusion 552 is formed by locally softening the top of the intermediate 540 and increasing the pressure in the intermediate 540. The protruding portion 552 may be formed immediately after being wound along the conical surface of the forming jig 590 or may be formed after being removed from the forming jig 590.

(2) Phosphor application process Application Step A step of applying a phosphor to the inner peripheral surface of the glass tube 515 constituting the intermediate 540 manufactured as described above will be described with reference to FIG. In addition, FIG. 7 is a figure explaining the process of apply | coating fluorescent substance.

  First, the phosphor to be used is for a three-wavelength region, and a suspension containing the above-described three types of red, green, and blue light emission is manufactured. In addition to the phosphors described above, the suspension to be produced includes a thickener (for example, polyethylene oxide (PEO) 2 (wt%)), a binder (for example, lanthanum oxide aluminum (LAF) 2 (wt %)), A surfactant (for example, Neugen), and a pH adjusting liquid (for example, ammonia), respectively.

Next, as shown in FIG. 7A, the intermediate 540 is arranged so that the intermediate part 542 is on the top. At this time, the intermediate body 540 is arranged such that its central axis A1 is substantially vertical.
In this state, the suspension is injected from one end, for example, the end 546. This suspension is injected by, for example, an injection nozzle (not shown), and the injected suspension goes up inside the winding part 548. The injection amount of the suspension per unit time is 1 (l / min) to 3 (l / min).

  Then, when the tip of the suspension that moves up the winding portion 548 of the intermediate body 540 toward the intermediate portion 542 exceeds the intermediate portion 542, the suspension injection is stopped. Then, as shown in FIG. 7B, the suspension in the intermediate 540 is discharged, and the intermediate 540 is arranged in a posture in which the central axis A1 of the intermediate 540 is substantially vertical. The intermediate body 540 is rotated around its central axis A1 as the center of rotation, and the suspension remaining in the intermediate body 540 is discharged.

The direction in which the intermediate body 540 rotates is opposite to the direction from the intermediate portion 542 toward the end portions 544 and 546 of the glass tube (δ direction in FIG. 7B).
When the discharge of the suspension is completed, the suspension is injected into the winding unit 550 from the other end 544. Also at this time, the suspension is injected until the tip of the suspension exceeds the intermediate portion 542, and then the intermediate body 540 is rotated in the δ direction with the central axis A1 as the center of rotation so that the suspension remaining in the winding portion 548 is obtained. Discharge.

As a result, the suspension is applied to the inner peripheral surfaces of the intermediate portion 542 and the two winding portions 548 and 550. In addition, the rotation of the intermediate body 540 at this time is performed at a speed of 1 rotation / 25 seconds.
B. About the drying process When the discharge of the suspension in the intermediate 540 is completed, as shown in FIG. 7C, hot air is blown to the outer periphery of the intermediate 540 to remove the suspension in the intermediate 540. dry. At this time, the intermediate body 540 also rotates around the central axis A1 as the rotation center, as in the case of discharging the suspension in the coating step. The rotation of the intermediate 540 at this time is 1 rotation / 25 seconds.

In addition, warm air is alternately flowed into the inside from both ends 544 and 546 of the intermediate 540 so that the drying is completed earlier. The temperature of the warm air blowing on the intermediate 540 is set to about 45 ° C., and is performed for about 13 to 15 minutes including the discharge of the suspension.
The warm air is poured into the intermediate 540 using, for example, a warm air nozzle. The amount of warm air flowing out from the warm air nozzle is about 7 (l / min). The temperature is about 45 ° C. Thus, when the drying of the suspension applied to the inner peripheral surface of the glass tube constituting the intermediate 540 is completed, the application to the inner peripheral surface of the phosphor is completed.

Here, the phosphor contained in the suspension has an average particle diameter of about 5 (μm), and the film thickness of the phosphor applied to the inner peripheral surface of the glass tube constituting the intermediate 540 is as follows. The viscosity of the suspension is adjusted so as to be 18 ± 3 (μm).
(3) Intermediate Deformation / Baking Process Next, a process of deforming the substantially cone-shaped intermediate body into a flat shape and firing the phosphor to complete the arc tube body will be described. FIG. 8 is a diagram for explaining the deformation / firing process.

A. About a deformation | transformation apparatus Deformation of the intermediate body 540 is performed using the deformation | transformation apparatus 580 as shown in FIG.
As shown in FIG. 8A, the deforming device 580 has a structure in which the intermediate body 540 is sandwiched from the central axis direction (vertical direction in FIG. 8), and the pair of flat plates are opposed to each other. For example, it is composed of a plurality of guide bars that guide the upper flat plate downward so that the surfaces can move in a substantially parallel state. Specifically, one of the pair of flat plates is a fixed plate 582 having a mounting surface 582a on which the intermediate body 540 is mounted, and the other is arranged above the fixed plate 582 and a guide bar. The movable plate 584 is movable in a direction (vertical direction in FIG. 8) perpendicular to the placement surface 582a of the fixed plate 582.

For example, six guide bars 586 are erected on the fixed plate 582. The guide rods 586 are provided at intervals in the circumferential direction along the glass tube that rotates around the outermost periphery of the intermediate body 540. It should be noted that restricting members 589 for restricting the proximity of the movable plate 584 to the fixed plate 582 are provided at the four corners of the mounting surface 582a of the fixed plate 582, respectively.
The movable plate 584 is provided with a through hole 587 in the approximate center so that the protruding portion 552 of the intermediate body 540 can be accommodated, and six guide holes 585 corresponding to the positions of the guide rods 586.

B. Deformation / Baking Step Next, the step of deforming the intermediate 540 into a flat shape and baking the phosphor will be described.
First, the deformation device 580 is prepared, and an intermediate body 540 is set between the movable plate 584 and the fixed plate 582 as shown in FIG.

The setting position is a predetermined position on the mounting surface 582a of the fixed plate 582, for example, approximately the center, and is a position where the protruding portion 552 of the intermediate body 540 just enters the through hole 587 of the movable plate 584. At this time, the peripheral edge of the through hole 587 of the movable plate 584 comes into contact with the intermediate portion 542 of the intermediate body 540.
Next, with the movable plate 584 in contact with the intermediate portion 542 of the intermediate body 540, the temperature of the outer peripheral surface of the glass tube in the intermediate body 540 is about 600 (° C.) as shown in FIG. ) To heat.

  In addition, this temperature is set about 75 (degreeC) low with respect to the softening point (675 degreeC) of glass (soft glass). This is because when the temperature of the intermediate body 540 is equal to or higher than the softening point, the glass tube starts to deform due to its own weight and the shape of the glass tube cannot be maintained, and the cross-sectional shape becomes irregular. Further, when the temperature is raised to the vicinity of the softening point of the glass tube, there arises a problem such that the phosphor is peeled off from the glass tube.

When the temperature of the outer peripheral surface of the glass tube of the intermediate body 540 becomes around 600 (° C.), the intermediate body 540 can be plastically deformed, and the movable plate 584 starts to descend (approach the fixed plate 582) by its own weight. That is, the intermediate body 540 starts to be compressed and deformed in the central axis direction. This deformation continues until the movable plate 584 comes into contact with the regulating member 589 of the fixed plate 582.
As shown in FIG. 8C, the state in which the movable plate 584 is in contact with the regulating member 589 is flat except for the protruding portion 552 entering the through hole 587 of the movable plate 584. It has become. Thereby, the flat arc tube main body 110 is obtained.

Further, the heating temperature for deforming the intermediate 540 is 600 (° C.) as described above, and this temperature is a phosphor applied to the inner peripheral surface of the glass tube 554 constituting the intermediate 540. The phosphor layer 160 is formed on the inner peripheral surface of the glass tube 112.
The deformation / firing process is performed using, for example, a heating furnace shown in FIG.

  In the heating furnace 600, the temperature in the furnace is set to 680 (° C.), and the deformation device 580 in which the intermediate 540 is set is conveyed into the furnace by a conveying device, for example, a conveyor 610. . Then, the intermediate body 540 is heated to approximately 600 (° C.) while being conveyed through the inside of the heating furnace 600, and the glass tube 112 on which the phosphor layer 160 is formed is deformed by the deforming device 580. The arc tube body 110 is completed by being compressed from the central axis direction and deformed into a flat shape and firing the phosphor.

<Modification>
Although the present invention has been described based on the embodiments, the content of the present invention is not limited to the specific examples shown in the above embodiments. For example, the following modifications are possible. Can be implemented.
1. Phosphor Application Step (1) Regarding the posture of the intermediate body In the embodiment, when the suspension injected into the intermediate body 540 is discharged, the intermediate body 540 is rotated so that the central axis A1 thereof is vertical. However, for example, the suspension may be discharged while the intermediate body is rotated while the intermediate body is rotated.

FIG. 10 is a diagram illustrating a case where the suspension is discharged while the intermediate body is inclined.
First, as shown in FIG. 10A, the intermediate body 540 is arranged in a state where the intermediate portion 542 is on the top and the central axis A1 of the intermediate body 540 is vertical, and in this state, Inject the suspension from one end. This suspension is performed until the injected suspension goes up inside the winding part and exceeds the intermediate part 542.

  Thereafter, the suspension in the intermediate body 540 is discharged as shown in FIG. 10B, and the posture of the intermediate body 540 is set at a predetermined angle (the center axis A1 with respect to the horizontal axis S in FIG. 10). In (b), it corresponds to γ, and the specific angle is about 45 degrees.) It is tilted, and the intermediate body 540 is rotated about its central axis A1 as the rotation axis, so that it enters the intermediate body 540. Drain remaining suspension. The direction in which the intermediate 540 rotates is the same as in the embodiment.

When the suspension is discharged, the intermediate body 540 is returned to the (tilt) posture (see FIG. 10A), and the suspension is injected into the winding portion of the intermediate body 540 from the other end. After that, the posture of the intermediate body 540 is tilted and the intermediate body 540 is rotated to discharge the suspension remaining in the winding portion.
When the outflow of the suspension in the intermediate 540 is completed, as shown in FIG. 10C, warm air is blown to the outer periphery of the intermediate 540 to dry the suspension in the intermediate 540. At this time, the intermediate body 540 rotates with the central axis A1 of the intermediate body 540 as the center of rotation in an inclined posture as in the case of discharging the suspension in the discharging step.

When the intermediate body 540 is inclined in this manner, the suspension can be reliably discharged and the suspension can be uniformly applied to the inner peripheral surface of the glass tube.
When the intermediate body is inclined, the inclination angle γ of the central axis A1 of the intermediate body with respect to the horizontal axis S shown in FIG. 10B is preferably about 40 to 45 degrees. This angle is considered to change depending on the inclination angle with respect to the central axis of the glass tube constituting the intermediate, or the viscosity of the suspension, the type of solvent contained in the suspension, the temperature of the hot air during drying, etc. It is necessary to determine appropriately by experiment.

In the description of the embodiment and the modification example here, when the suspension is injected into the glass tube constituting the intermediate 540, the posture of the intermediate 540 is not inclined (the center axis A1 is in a vertical state). However, for example, the suspension may be injected while the intermediate 540 is inclined.
Further, when the suspension is discharged, the intermediate body 540 rotates with the central axis A1 as the rotation axis in a state where the central axis A1 is inclined at a certain angle with respect to the vertical axis. The body 540 may be rotated while changing the tilt state within a range of a predetermined angle.

(2) About rotation of intermediate body In the embodiment, when discharging the suspension, the intermediate body 540 is rotated about its central axis A1 as a rotation axis. However, the rotation axis is located inside the intermediate body 540. What is necessary is just to be able to discharge the injected suspension, and not the central axis A1 of the intermediate 540 but the vertical axis or the horizontal axis S, for example.

In addition, in the embodiment, the rotation speed was 1 rotation / 25 seconds, but this speed is naturally the viscosity of the suspension, the size of the intermediate, the thickness of the glass tube, and the shape of the intermediate. (For example, the angle with respect to the central axis of the glass tube in the swivel portion) and the like, and it is preferable to appropriately determine by experiment.
Furthermore, although the speed at which the intermediate 540 rotates is set to be constant in the embodiment, for example, the speed at which the suspension is discharged and the speed at which the suspension is dried may be changed to rotate. good. In this case, the speed at the time of discharging and drying may be constant, and for example, the speed may be set to change halfway between the start and end of rotation.

(3) Method of applying suspension In the embodiment, when the suspension is injected from the end portions 544 and 546 of the intermediate body 540 and the tip of the suspension in the glass tube exceeds the intermediate portion 542, the injection is performed. However, for example, the injection of the suspension may be continued, and the injection may be performed until the suspension is poured out from the other end.

That is, the application of the suspension to the inner peripheral surface of the glass tube is not limited to the embodiment and the method described above as long as the suspension is applied.
2. Regarding the shape of the cone-shaped intermediate body The intermediate body 540 in the above description has a substantially conical shape, and the angle α (see FIG. 5A) between the generatrix and the central axis A is 53. The angle α may be in the range of 45 degrees or more and 70 degrees or less.

  When the angle α is larger than 70 degrees, the step H of the recessed portions 595 and 596 of the forming jig 590 is smaller than 0.5 times the outer diameter of the glass tube, and the cone shape is formed from the straight tubular glass tube. If the angle α is smaller than 45 degrees, the yield of non-defective products when deformed from a cone-shaped intermediate body to a flat arc tube body is significantly reduced. Because it gets worse.

When the angle α is 53 degrees, the production yield of the arc tube main body 110 having a flat double helix shape from a straight glass tube is 90 (%) or more. Was good.
The reason why the step H of the recessed portions 595 and 596 formed on the outer peripheral surface of the main body portion 591 of the forming jig 590 is 0.56 times the outer diameter of the glass tube 510 is that the arc tube described above. The gap Ga between the adjacent glass tubes 112 in the main body 110 is set to 1.5 (mm) to 6 (mm) so as not to cause luminance unevenness, and as shown in FIG. 6, the bus bar of the conical surface of the forming jig 590 This is because the angle β between B1 and the axis B is set to about 60 degrees for the reason described above.
3. Regarding the temperature of the intermediate in the deformation step In the above description, the temperature of the intermediate 540 in the deformation step (this temperature is hereinafter referred to as “temperature during compression”) is set to 600 (° C.). The temperature should be higher than the temperature at which the glass tube 112 can be plastically deformed without cracking (it was 550 (° C.) in the experiment) and lower than the softening point (675 (° C.)) of the glass tube 112.

  When the temperature at the time of deformation becomes equal to or higher than the softening point of the glass tube 112, the glass tube 112 becomes softened and cannot maintain its own shape, and the cross-sectional shape of the glass tube 112 changes from a substantially circular shape to other distorted shapes. Or the adjacent glass tube 112 is deformed too much and comes into contact, and further, the diameter of the end portion of the glass tube becomes thin and the glass tube extends in the axial direction accordingly.

In the actual process, considering the variation of the material of the glass tube itself, the variation of the temperature of the apparatus at the time of heating, etc., the temperature at the time of deformation may be in the range of 580 (° C.) or more and 635 (° C.) or less. It ’s fine. This is the temperature at which the cross-sectional shape of the glass tube can be maintained in a substantially circular shape and can be processed into a flat shape.
Note that the firing temperature of the phosphor may be not less than 550 (° C.) and not more than 650 (° C.), which is almost the same as the heating temperature for deforming the glass tube.
4). Regarding the shape of the arc tube body In the embodiment, the arc tube 100 has a flat double spiral shape, but the shape of the arc tube 100 according to the present invention is not limited to a flat double spiral shape. For example, the arc tube body may be formed by flatly deforming a part of the cone-shaped intermediate body. Furthermore, the single spiral shape which has one turning part may be sufficient.

Further, in the embodiment, the swiveling portions 122 and 124 have a shape that turns around the predetermined axis A in an arc shape. For example, the swiveling portion has a polygonal shape when viewed from a predetermined direction, for example, It may be a shape that turns into a quadrangular shape.
Furthermore, in the embodiment, the arc tube main body 110 is swung around the predetermined axis A in the entire range from the intermediate portion 120 to the end portions 114 and 116. A portion up to a predetermined position may turn.
5. About the cone shape (the outer shape of the intermediate body) The outer shape of the intermediate body 540 in the embodiment is a cone shape, but the cone shape in the present invention is not limited to the cone shape. The external shape of the intermediate body may be a polygonal pyramid shape such as a quadrangular pyramid shape.

Further, the intermediate body 540 has a single glass tube 510 that has its central portion (510a) hooked on the top of the forming jig 590, and forms a portion on each end side from the central portion of the glass tube 510. It is formed in a double spiral shape by winding along the conical surface of the tool 590. For example, one end of the glass tube is hooked on the top of the forming jig, and the other end from this end A single spiral shape in which the portion up to is wound along the conical surface of the forming jig may be used. Also in this case, the shape of the forming jig (main body portion) is not limited to the conical shape.
6). Flat shape (outer shape of arc tube body) The outer shape of the arc tube body 110 in the embodiment is flat (the axis of the glass tube is substantially in the same plane). All may be in a shape located in the same plane, or a shape in which a part of the axis of the glass tube is located in the same plane.

  In addition, the arc tube body 110 in the embodiment has a shape in which the turning part turns around the predetermined axis A in an arc shape when viewed from the extending direction of the predetermined axis. It may be shaped so as to turn around a predetermined axis in a straight line so as to constitute one side of a polygonal shape such as a triangular shape. In addition, in order to turn the glass tube linearly around a predetermined axis, it is necessary that the above-mentioned cone shape has a polygonal cone shape.

  INDUSTRIAL APPLICABILITY The present invention can be made smaller than the outer diameter of a conventional ring fluorescent lamp and can be used to efficiently manufacture an arc tube.

The perspective view of the fluorescent lamp which is embodiment of this invention It is the figure which looked at the fluorescent lamp from the lower part in FIG. It is the figure which looked at the fluorescent lamp from the X direction in FIG. 2, and the figure which notched the part so that the mode inside the holder could be understood The figure for demonstrating the process of manufacturing an arc tube main body 4A is a partially cutaway side view of the intermediate body in FIG. 4B, and FIG. 5B is a view when the intermediate body is viewed from the Y direction in FIG. The figure explaining the process of forming an intermediate The figure explaining the process of apply | coating fluorescent substance Diagram explaining deformation / firing process Schematic of the heating furnace used in the deformation / firing process The figure explaining the process of apply | coating the fluorescent substance in a modification

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fluorescent lamp 100 Light emission tube 110 Light emission tube main body 112 Glass tube 114,116 End part 120 Intermediate part 122,124 Turning part 200 Holder 510 Glass tube 540 Intermediate body 542 Intermediate part 548,550 Winding part 580 Deformation device A Predetermined axis A1 Central axis

Claims (2)

Forming the glass tube into a cone shape formed by heating the glass tube to a temperature equal to or higher than the softening point temperature and winding it along the cone surface of the cone-shaped forming jig; and the softening point of the cone-shaped glass tube. Deformation in which at least part of the axis of the glass tube is heated to a temperature that is lower than the temperature and at which the glass tube can be deformed, and is deformed into a flat shape that is included in a plane substantially perpendicular to the central axis of the cone shape. the method for manufacturing a light emitting tube and a step, between said deforming step and said forming step, coating step there for applying a fluorescent material on the inner peripheral surface of the glass tube that is formed in the cone-shaped Ri A method for manufacturing an arc tube , wherein the applied phosphor is baked using heat at the time of heating in the deformation step . In the forming step, the central portion of the glass tube is hooked on the top of a cone-shaped forming jig, and the portion from the central portion of the hooked glass tube to the end is halfway in the conical shape. 2. The method of manufacturing an arc tube according to claim 1, wherein the arc tube is formed in a double spiral cone shape wound along a conical surface of the forming jig.

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