JP2000340111A - Method and device for manufacturing fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower atmospheric temperature in a kiln, to shorten burning time and to miniaturize equipment by blowing gas with almost equal temperature to the objective temperature of a glass tube, into the glass tube when burning a phosphor formed on the inner surface of the glass tube. SOLUTION: A glass tube 11 with phosphor suspension applied to the inner surface is put in a furnace 10. At this time, air is put inside the glass tube 11 to decompose a binder. The temperature of the blown gas (air) is made almost equal to the objective glass tube temperature (burning temperature). Because of little change in the temperature of the glass tube 11 by blowing such a high temperature gas 12, the interior of the glass tube 11 can be raised to specified temperature in an instant, and the temperature can be maintained without overshooting. As a result, atmospheric temperature can be lowered, temperature rise time can be shortened, and the length of the furnace 10 can be shortened. In order to blow the high temperature gas 12 positively into the glass tube 11, it is referable to provide a blast tube 20 almost parallel with the glass tube 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for manufacturing a fluorescent lamp. In particular, the present invention relates to a method and an apparatus for manufacturing a fluorescent lamp in which a phosphor is fired while blowing a gas having a temperature substantially equal to a target glass tube temperature into the glass tube.

[0002]

2. Description of the Related Art A fluorescent lamp is manufactured through the steps of cleaning a glass tube, applying a protective film, applying a phosphor, baking, sealing, exhausting, basing and aging.

[0003] In the phosphor coating step, the phosphor suspension is poured from above with the glass tube being vertical, and thereafter,
The phosphor suspension is dried with hot air of 70 ° C. to adhere to the inner wall of the glass tube. The phosphor suspension contains a mixture of a phosphor, a binder, pure water, an organic binder, a surfactant, an antifoaming agent, and ammonia. Nothing other than a phosphor and a binder is required for a fluorescent lamp. The organic binder is used to attach the phosphor suspension to the inner wall of the glass tube during application, the surfactant is used to prevent the occurrence of unapplied parts, the defoamer is used to prevent poor foaming, and the ammonia is used to prevent precipitation of the phosphor. , Each is mixed. Therefore, these unnecessary organic binders after coating,
It is necessary to decompose and remove surfactants, defoamers and ammonia. For this purpose, the phosphor is fired in the next step.

[0004] A baking apparatus used in a conventional phosphor baking process of a fluorescent lamp will be described with reference to FIG. As shown, the glass tube 101 is moving in the direction of movement 105 while rotating inside the firing furnace 100. On the way, air 102 is blown into the glass tube to assist the combustion of the organic matter. Reference numeral 103 denotes a shielding plate (or blowing pipe) installed substantially parallel to the tube axis direction of the glass tube 101 to align the blowing direction of air in a predetermined direction. If air is not blown into the glass tube, it will be in an oxygen-deficient state, and the binder will not be decomposed and the carbon will remain in the glass tube and become colored. The furnace atmosphere temperature during firing is about 800 ° C., the glass tube holding temperature in the furnace is about 640 ° C., and the air to be blown is heated to about 300 ° C. by furnace heat and blown into the glass tube.
The time for raising the temperature of the glass tube to 640 ° C. is 70 minutes.
Seconds and the hold time is 90 seconds. The temperature of the glass tube when gradually cooled in the furnace and leaving the firing furnace is about 300 ° C. It is the first half of the furnace that blows air into the glass tube.

[0005]

In the above-described firing apparatus,
The air sent into the glass tube is only heated by the furnace heat, and is about 300 ° C., which is much lower than the glass tube temperature of 640 ° C. In order to blow air having a temperature lower than the glass tube temperature, the temperature of the glass tube decreases, and in order to raise the temperature of the glass tube to a predetermined temperature, a higher furnace atmosphere temperature and long-time heating are required. Therefore, the conventional method uses more energy than necessary and should be improved from the viewpoint of energy saving. In addition, the process speed cannot be increased due to the necessity of heating for a long time, and there is a problem in productivity. Alternatively, it is necessary to increase the moving distance of the glass tube, which increases the size of the equipment and hinders cost reduction.

The present invention solves the above-mentioned conventional problems and can lower the furnace atmosphere temperature, thereby lowering the energy cost, and shortening the firing time and miniaturizing the equipment. An object of the present invention is to provide a method and an apparatus for manufacturing a fluorescent lamp.

[0007]

In order to achieve the above object, the present invention has the following arrangement.

[0008] The method of manufacturing a fluorescent lamp according to the present invention is characterized in that when firing the phosphor formed on the inner surface of the glass tube, a gas having a temperature substantially equal to the target glass tube temperature is blown into the glass tube. I do. Further, the apparatus for manufacturing a fluorescent lamp according to the present invention includes a baking furnace for baking the phosphor formed on the inner surface of the glass tube, and a blower for blowing a gas having a temperature substantially equal to a target glass tube temperature into the glass tube. And a device. According to this configuration, the temperature of the glass tube can be instantaneously increased to a predetermined temperature, and the temperature can be maintained without overshoot. Therefore, the furnace atmosphere temperature was set to 8
The temperature is reduced from 00 ° C to 750 ° C, and there is an energy saving effect of 50 ° C. In addition, since the heating rate is high, the heating time is reduced from 70 seconds to 5 seconds.
It can be shortened to 0 seconds, and the furnace length can be shortened.

In the above, it is preferable that the atmosphere gas at the time of firing and the gas blown into the glass tube include oxygen or sulfurous acid gas. Oxygen assists in the decomposition of the binder, and sulfur dioxide increases the strength of the glass tube and the adhesion of the phosphor to the glass tube. By including the sulfurous acid gas, the firing temperature of the glass tube can be reduced while maintaining the adhesive strength of the phosphor. Therefore, the following effects can be further obtained. When firing a glass tube with a Nesa film,
When the temperature of the glass tube is set to be equal to or lower than the film forming temperature of the nesa film at 600 ° C., an increase in resistance value due to gas adsorption of the nesa film at the time of sintering of the phosphor can be suppressed, and lighting start failure of the fluorescent lamp can be reduced. When the temperature of the glass tube is 550 ° C. or less,
In the case of a three-wavelength phosphor, it is possible to prevent a decrease in luminance of each color component. Further, the deformation of the glass tube, which occurs when firing at 550 ° C. or more, can be prevented, and the rotation mechanism of the glass tube necessary for suppressing the deformation of the glass tube becomes unnecessary.

In the above manufacturing method, it is preferable that the gas in the glass tube is exhausted from a side opposite to a side where the gas is blown into the glass tube. Further, in the above manufacturing apparatus, it is preferable that an exhaust pipe for exhausting gas in the glass tube is provided at an end of the glass tube on a side opposite to the blower. According to such a configuration, exhaust gas such as carbon dioxide generated during decomposition of the binder in the glass tube can be reliably exhausted outside the tube.

In the above-mentioned manufacturing method, it is preferable that a blowing section for blowing gas to be blown into the glass tube is introduced into the glass tube, and the gas is blown while moving the blowing section in the glass axis direction in the glass tube. Further, in the above-described manufacturing apparatus, it is preferable that the blower has a blowing unit for blowing the gas into the glass tube, and the blowing unit is movable in the tube axis direction in the glass tube. According to this configuration, the temperature of the glass tube can be efficiently and instantaneously increased by heating from inside the glass tube. In addition, by moving the blowing section in the tube axis direction, the temperature can be uniformly increased in the longitudinal direction.

In the above method, it is preferable that the gas blown into the glass tube is blown in a direction substantially perpendicular to the inner surface of the glass tube on which the phosphor is formed. Further, in the above manufacturing apparatus, it is preferable that the blower has a blowing section for blowing the gas in a direction substantially perpendicular to an inner surface of the glass tube on which the phosphor is formed. According to such a configuration, it is possible to efficiently bake by blowing the hot air directly onto the phosphor.

In the above-mentioned manufacturing method, it is preferable that a plurality of blow-off portions for blowing gas to be blown into the glass tube are provided in the glass tube in a tube axis direction. Further, in the above-mentioned manufacturing apparatus, it is preferable that the blower has a plurality of blow-off portions for blowing out the gas in the glass tube direction in the glass tube. According to such a configuration, the temperature of the glass tube can be efficiently raised by simultaneously blowing the gas from the plurality of outlets. Further, the temperature of the glass tube can be uniformly increased in the longitudinal direction.

In the above manufacturing method, it is preferable that the firing is performed while rotating the glass tube. Further, in the above-mentioned manufacturing apparatus, it is preferable to have a rotating device for rotating the glass tube during firing. According to such a configuration, the temperature in the circumferential direction of the glass tube can be made uniform. Further, the warpage of the glass tube can be reduced and the roundness can be increased.

In the above manufacturing method, it is preferable that the gas to be blown into the glass tube is blown out from a blowing portion formed long in the circumferential direction of the glass tube. Also,
In the above-described manufacturing apparatus, it is preferable that the blower has a blow-out portion formed to be long in a circumferential direction of the glass tube and to blow out the gas. According to this configuration, the gas can be sprayed substantially uniformly in the circumferential direction of the glass tube, so that the temperature in the circumferential direction of the glass tube can be made uniform.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) A first embodiment will be described with reference to FIG.

The glass tube 11 is placed in a phosphor firing furnace 10 in order to fire the glass tube 11 having the phosphor suspension coated on its inner surface. At this time, if air is not blown into the glass tube 11, oxygen deficiency occurs and the binder cannot be decomposed.

In the conventional method, the blown air is heated only at the ambient temperature of the furnace. Therefore, when the temperature of the glass tube is 640 ° C., the temperature of the air immediately before being blown into the glass tube is about 300 ° C., which is extremely lower than the temperature of the glass tube, and the glass tube is cooled.

Therefore, in the present invention, the temperature of the gas 12 to be blown is set substantially equal to the target glass tube temperature (firing temperature). In this method, since the temperature hardly changes due to the blowing of the gas 12, the temperature inside the glass tube 11 can be instantaneously raised to a predetermined temperature, and the temperature can be maintained without overshoot. Accordingly, the ambient temperature can be reduced from the current 800 ° C. to 750 ° C., and the heating time can also be reduced from the current 70 seconds to 50 seconds, which has an energy saving effect and can shorten the furnace length.

In FIG. 1, reference numeral 20 denotes a blower tube installed substantially parallel to the glass tube 12 so that the gas 12 can be reliably blown into the glass tube 11.

(Embodiment 2) A second embodiment will be described with reference to FIGS. 2, 3 and 4. FIG.

It is important that the bonding strength is high when the phosphor is bonded in the glass tube. The bonding strength can be increased by firing the phosphor at a high temperature. However, the firing temperature is preferably low from the viewpoint of energy saving and from the viewpoint of avoiding deterioration of the phosphor. Therefore, if a sulfurous acid gas is blown into the glass tube during the firing of the phosphor, the adhesive strength can be increased without increasing the firing temperature.

FIG. 2 shows the results of examining the occurrence of peeling of the phosphor film obtained by changing the concentration of sulfurous acid contained in the atmosphere gas during firing and the firing temperature, respectively. As shown in the figure, the higher the firing temperature and the higher the concentration of the sulfurous acid gas, the more difficult the peeling is to occur, and there is a “region without peeling” indicated by oblique lines. From FIG. 2, if a certain baking temperature is selected, it is possible to determine the concentration of the sulfur dioxide gas at which the phosphor film does not peel off at that temperature.

The sulfurous acid gas is preferably blown in a mixture with oxygen. Thereby, the adhesive strength can be increased together with the decomposition of the binder. Then, the firing temperature can be lowered.

When the firing temperature is lowered, there are the following advantages.

In a rapid start type fluorescent lamp in which a Nesa film is formed on the surface of a glass tube, a change in the resistance value of the Nesa film is a problem. The Nesa film is used as a gas sensor, and has a property that a resistance value increases when a gas is adsorbed on a grain boundary and decreases when a gas is desorbed.

FIG. 3 shows how the total resistance value of the Nesa film changes. At the current firing temperature of 640 ° C., the Nesa film is oxidized and the resistance value increases. Thereafter, the resistance value of the Nesa film gradually decreases due to desorption of gas during the evacuation process, the aging process, and the lighting, and the initial resistance value when the Nesa film is formed several hundred hours after lighting. Return to the value of.

If the resistance value of the Nesa film is high, the starting voltage increases, and if the resistance value is low, the BSP (Black Spot Patc) increases.
h) occurs. If the resistance value of the Nesa film is reduced in order to prevent poor starting, the resistance value decreases during lighting and BSP occurs.

When the firing temperature of the glass tube is set to 600 ° C. or lower, oxidation of the nesa film does not occur, the increase in the resistance value can be suppressed, and defective starting of the fluorescent lamp can be prevented.

When the phosphor is fired in an oxygen atmosphere, the phosphor is deteriorated by oxidation, and the luminance is reduced. FIG. 4 is a diagram showing how the relative luminance of each of the red, green, and blue color components of the phosphor changes depending on the firing temperature. As is clear from FIG.
In the case of a three-wavelength phosphor, the blue phosphor deteriorates particularly at a firing temperature of 550 ° C. or higher. When the glass tube is fired at 550 ° C. or lower, deterioration of the blue phosphor can be prevented, and a fluorescent lamp having a high total luminous flux can be obtained. Thus, the amount of the phosphor applied can be reduced. Therefore, the quality of the fluorescent lamp can be improved.

Further, it is possible to prevent deformation of the glass tube generated when firing at a high temperature, to stabilize the quality, and to eliminate the need for a glass tube rotating device for suppressing the deformation of the glass tube. , And cost reduction becomes possible.

(Embodiment 3) A third embodiment will be described with reference to FIG.

At the time of burning the phosphor, a part of the binder burns, and if carbon dioxide remains in the glass tube 11, the subsequent burning is hindered. Therefore, in the present embodiment, an exhaust pipe 30 for exhausting the exhaust gas in the glass tube 11 is disposed at the end of the glass tube opposite to the side that blows the gas into the glass tube. Thereby, the exhaust gas 31 such as carbon dioxide generated in the glass tube can be reliably exhausted outside the tube.

It is preferable that the exhaust pipe 30 is connected to an exhaust pump (not shown) to forcibly exhaust the exhaust gas, whereby the exhaust gas can be reliably exhausted.

(Embodiment 4) A fourth embodiment will be described with reference to FIG.

In this embodiment, the blower tube 21 for the high-temperature gas 12 is introduced into the glass tube 11 and the high-temperature gas is supplied to the glass tube 1.
Blow out within 1. At the same time, the blower tube 21 is connected to the glass tube 1.
Within 1, it moves in the glass tube axis direction (the direction of the arrow 21 a).

According to the present embodiment, since the hot gas blow-off portion of the blower tube is provided in the glass tube and is moved (preferably reciprocated) in the glass tube, the glass tube is also heated from the inside. Can be. Therefore, the temperature of the glass tube can be efficiently and instantaneously increased. Also, by moving the blower tube in the tube axis direction,
The temperature distribution in the tube axis direction can be made uniform.

(Fifth Embodiment) A fifth embodiment will be described with reference to FIG.

In this embodiment, a blower tube 22 having a hot gas outlet on the outer peripheral surface of the blower tube is used instead of the blower tube 21 of the fourth embodiment.

When a high-temperature gas is blown from the end of the glass tube 11, the high-temperature gas flows parallel to the phosphor film, so that the effect of raising the temperature is small. As in the present embodiment, by disposing the outlet of the high-temperature gas inside the glass tube 11 at a position where the high-temperature gas hits the phosphor film substantially perpendicularly, the temperature-raising effect is further improved. I do.

At this time, the blower tube 22 is connected to the glass tube 1.
It is preferable to move in the glass tube axis direction (direction of arrow 22a) within 1.

(Embodiment 6) A sixth embodiment will be described with reference to FIG.

In the present embodiment, instead of the blower tube 22 of the fifth embodiment, a blower tube 23 provided with a plurality of hot gas outlets in the longitudinal direction on the outer peripheral surface of the blower tube is used.

When there are a plurality of high-temperature gas outlets, high-temperature gas can be simultaneously blown from the plurality of outlets, and the temperature of the glass tube 11 can be increased more efficiently and substantially uniformly.

As in the fifth embodiment, the blower tube 23
May be moved in the glass tube axial direction in the glass tube 11. Thereby, the temperature distribution in the longitudinal direction of the glass tube can be made more uniform.

(Seventh Embodiment) A seventh embodiment will be described with reference to FIG.

In this embodiment, the high-temperature gas 12 is blown while rotating the glass tube 11. Reference numeral 24 denotes a high-temperature gas blower tube, and the method of blowing the high-temperature gas may be any of the first to third embodiments.

When the glass tube 11 is rotating, the temperature distribution in the circumferential direction can be made uniform, and the warpage of the glass tube 11 can be reduced.

(Eighth Embodiment) An eighth embodiment will be described with reference to FIG. FIG. 10A is a perspective view of a blower tube according to the present embodiment, and FIG.
FIG. 3 is a cross-sectional view when viewed in a direction of an arrow along a line -I.

The blower tube 25 of the present embodiment has a hot gas outlet 25a on the outer peripheral surface. Outlet 25a
Is formed in a long hole shape in which the major axis direction of the opening substantially coincides with the circumferential direction. Further, a plurality of such elongated holes 25a (four in the example of FIG. 10) are provided in the circumferential direction. By using such a blower tube 25,
Since the high-temperature gas can be blown substantially uniformly in the circumferential direction, the temperature distribution in the circumferential direction of the glass tube can be made uniform.

It is preferable that the blower tube 25 is inserted into the glass tube and moved in the glass tube axial direction as described in the fifth embodiment. Thereby, the temperature distribution in the longitudinal direction of the glass tube can be made uniform.

As described in the sixth embodiment, a plurality of outlets may be arranged in the longitudinal direction.

According to the methods of Embodiments 3 to 8, the combustion efficiency is improved and the firing time can be shortened. The current firing time is 90 seconds, but can be reduced to 60 seconds. A total reduction of 50 seconds is possible in addition to the reduction of the heating time of 20 seconds described in the first embodiment. With this shortening, the furnace length can also be reduced to 3/4 of the current furnace.

[0055]

As described above, by blowing a gas having substantially the same temperature as the ambient temperature of the phosphor firing furnace into the glass tube, the temperature of the glass tube can be instantaneously raised to a predetermined temperature, and the overshoot can be achieved. Without the temperature can be maintained. Therefore, it is possible to lower the ambient temperature and shorten the furnace length, which is effective for energy saving, improvement of productivity and miniaturization of the apparatus. Further, the quality of the fluorescent lamp can be improved depending on the selection of the blowing gas component.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing a firing apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a state of occurrence of peeling of a phosphor film depending on a sulfurous acid gas concentration and a firing temperature.

FIG. 3 is a diagram showing a change in a total resistance value of a Nesa film.

FIG. 4 is a diagram showing a relationship between a firing temperature and a change in luminance of a phosphor.

FIG. 5 is a front view schematically showing a firing apparatus according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a method for blowing a high-temperature gas according to a fourth embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a method for blowing a high-temperature gas according to a fifth embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a method for blowing a high-temperature gas according to a sixth embodiment of the present invention.

FIG. 9 is a sectional view showing a firing method according to a seventh embodiment of the present invention.

FIG. 10 is a diagram showing a blower tube according to an eighth embodiment of the present invention, where (A) is a perspective view and (B) is a II of (A).
Sectional view when viewed in the direction of the arrow in the line

FIG. 11 is a perspective view schematically showing a conventional phosphor firing apparatus.

[Description of Signs] 10 Firing furnace 11 Glass tube 12 High-temperature gas 20, 21, 22, 23, 24, 25 Blast tube 30 Exhaust tube 31 Exhaust gas 100 Firing furnace 101 Glass tube 102 Air 103 Shield plate

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hideo Nagai 1-1, Sachimachi, Takatsuki-shi, Osaka Matsushita Electronics Co., Ltd. (72) Yoshio Yamaguchi 1-1, Sachimachi, Takatsuki-shi, Osaka Matsushita Electronics Inside (72) Inventor Koji Honda 1-1, Yukicho, Takatsuki-shi, Osaka Matsushita Electronics Co., Ltd.

Claims (16)

[Claims] 1. A method for manufacturing a fluorescent lamp, comprising: when baking a phosphor formed on an inner surface of a glass tube, blowing a gas having a temperature substantially equal to a target glass tube temperature into the glass tube. 2. The method for manufacturing a fluorescent lamp according to claim 1, wherein the atmosphere gas at the time of firing and the gas blown into the glass tube include oxygen or sulfurous acid gas. 3. The method for manufacturing a fluorescent lamp according to claim 1, wherein the gas in the glass tube is exhausted from a side opposite to a side where the gas is blown into the glass tube. 4. A gas blow-out unit for blowing out gas to be blown into the glass tube is introduced into the glass tube, and the gas is blown out while moving the blow-out unit in the glass tube direction in a tube axis direction. 3. The method for producing a fluorescent lamp according to item 1. 5. The method of manufacturing a fluorescent lamp according to claim 1, wherein a gas blown into the glass tube is blown in a direction substantially perpendicular to an inner surface of the glass tube on which the phosphor is formed. 6. The method for manufacturing a fluorescent lamp according to claim 1, wherein a plurality of blow-off portions for blowing gas to be blown into the glass tube are provided in the glass tube in a tube axis direction. 7. The method according to claim 1, wherein the firing is performed while rotating the glass tube. 8. The method for manufacturing a fluorescent lamp according to claim 1, wherein a gas blown into the glass tube is blown out from a blowing portion formed long in a circumferential direction of the glass tube. 9. A sintering furnace for sintering a phosphor formed on an inner surface of a glass tube, and a blowing device for blowing a gas having a temperature substantially equal to a target temperature of the glass tube into the glass tube. Fluorescent lamp manufacturing apparatus. 10. The fluorescent lamp manufacturing apparatus according to claim 9, wherein the atmosphere gas at the time of firing and the gas blown into the glass tube include oxygen or sulfurous acid gas. 11. The fluorescent lamp manufacturing apparatus according to claim 9, wherein an exhaust pipe for exhausting gas in the glass tube is provided at an end of the glass tube opposite to the blower. 12. The blower according to claim 9, further comprising a blower for blowing the gas into the glass tube, wherein the blower is movable in the tube axis direction in the glass tube.
12. The apparatus for manufacturing a fluorescent lamp according to any one of items 11 to 11. 13. The manufacture of the fluorescent lamp according to claim 9, wherein the blower has a blowing section for blowing the gas in a direction substantially perpendicular to an inner surface of the glass tube on which the phosphor is formed. apparatus. 14. The apparatus for manufacturing a fluorescent lamp according to claim 9, wherein the blower has a plurality of blow-off portions for blowing the gas in the glass tube in a tube axis direction. 15. The fluorescent lamp manufacturing apparatus according to claim 9, further comprising a rotating device for rotating said glass tube during firing. 16. The apparatus for manufacturing a fluorescent lamp according to claim 9, wherein the blower has a blow-off portion formed in the circumferential direction of the glass tube to blow out the gas.