JP3570711B2 - How to make a light bulb - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a light bulb, particularly a small and highly efficient light bulb.
[0002]
[Prior art]
Conventionally, as a general lighting bulb, an E26 base bulb with a glass bulb maximum outer diameter of about 55 mm to 75 mm, a length of about 98 mm to 155 mm, and a rating of 100 V or 110 V and a power of 10 W to 200 W has been widely known. In addition, a miniature bulb with an E17 base having a maximum outer diameter of about 35 mm to 45 mm, a length of about 67 mm to 81 mm, a rated voltage of 100 V or 110 V, and a power of 25 W to 100 W, which is further reduced in size while maintaining the luminous flux of the light bulb. Are also used as versatile and energy-saving light sources.
[0003]
The small light bulb has a disc-shaped heat shield plate at a position on the stem corresponding to the vicinity of the boundary between the light emitting portion and the neck portion of the glass bulb in order to reduce the thermal effect on the glass bulb neck portion during lighting. Is known.
[0004]
[Problems to be solved by the invention]
However, the light bulb provided with the heat shield plate has a problem that cracks are generated in a ring shape near the boundary between the light emitting part and the neck part of the glass bulb during the light bulb manufacturing process, during installation after the light bulb is completed, or during lighting. Was.
[0005]
FIG. 4 is a side view showing an example of a state in which a ring-shaped crack has occurred in a conventional light bulb. 4, reference numeral 20 denotes a light bulb, 21 denotes a glass bulb, 22 denotes a light emitting part of the glass bulb 21, 23 denotes a neck part of the glass bulb 21, 25 denotes a base, 27 denotes a heat shield plate, and 29 denotes a light emitting part 22 of the glass bulb 21. And ring-shaped cracks generated near the boundary between the ring and the neck portion 23.
[0006]
When such a crack 29 occurs, there has been a problem that the glass bulb 21 is damaged, or the neck portion 23 including the base 25 and the light emitting portion 22 are separated and one of them is dropped off.
[0007]
When the cause of the problem was investigated, the following causes were found.
[0008]
First, since the glass bulb 21 and the stem are too close to each other, the inner wall near the boundary between the light emitting part 22 and the neck part 23 of the glass bulb 21 when or after the stem is fitted into the glass bulb. The heat shield plate 27 is in contact with the peripheral edge and is damaged. Furthermore, the stress inside the glass bulb increases due to the residual strain after the sealing step and the repetitive thermal stress caused by repeating the turning on and off of the bulb. As a result, a crack is formed in a ring shape from the damaged portion in the glass bulb.
[0009]
Secondly, when the thickness near the boundary between the light emitting part 22 and the neck part 23 of the glass bulb 21 varies from one glass bulb to another due to a manufacturing error or the like, the annealing process after sealing is performed under the same conditions. In this case, the temperature of the glass bulb during the annealing process varies depending on the thickness. As a result, even if the annealing process is performed, the distortion during the sealing step is not sufficiently removed, and a crack is generated in a ring shape from a damaged portion of the inner wall of the glass bulb due to the contact with the heat shield plate.
[0010]
An object of the present invention is to solve the problems of the above-described conventional light bulbs and to provide a method of manufacturing a light bulb in which a ring-shaped crack does not occur in a glass bulb.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a method for manufacturing a light bulb according to the present invention includes a thickness measuring step of measuring a thickness of a boundary portion between a neck portion and a light emitting portion of a glass bulb, and a stem having an end portion of the neck portion. A method of manufacturing a light bulb having a sealing step of sealing and an annealing step of annealing the glass bulb after sealing in this order, based on the thickness value measured in the thickness measuring step. The annealing step in the annealing step is adjusted.
[0012]
The temperature of the glass bulb during the annealing process changes according to the thickness of the glass bulb. Therefore, by measuring the thickness of the boundary portion between the neck portion and the light emitting portion of the glass bulb where ring-shaped cracks are easily generated, and adjusting the annealing process conditions according to the measured value, the glass bulb during the annealing process is measured. Temperature can be properly controlled regardless of the wall thickness. Therefore, it is possible to prevent the occurrence of residual distortion and to prevent the occurrence of ring-shaped cracks near the boundary between the neck portion of the glass bulb and the light emitting portion.
[0013]
In the above, when the thickness measured in the thickness measuring step is larger than a predetermined reference value, it is preferable that the annealing process conditions in the annealing step be changed so as to increase the annealing temperature. When the wall thickness is large, the temperature of the glass bulb tends to be low in the annealing step. Therefore, with such a preferable configuration, it is possible to perform annealing at a desired temperature even on a thick glass bulb exceeding the standard, and it is possible to prevent the occurrence of ring-shaped cracks.
[0014]
Preferably, in the annealing step, the temperature of the glass bulb during the annealing process is measured, and the annealing process conditions in the annealing process are adjusted based on the measured temperature. According to such a preferable configuration, the annealing process can be always performed at a desired temperature regardless of a manufacturing error of the glass bulb and the like, and generation of a ring-shaped crack can be prevented.
[0015]
In the above, it is preferable that the adjustment of the annealing treatment condition is an adjustment of the thermal power of a gas burner for heating the glass bulb. This makes it possible to easily adjust the annealing conditions.
[0016]
When the measured thickness is smaller than a predetermined reference value in the thickness measuring step, it is preferable to exclude the glass bulb. Thin glass bulbs have low strength and ring cracks are likely to occur. Therefore, by selecting and excluding such glass bulbs, it is not only unnecessary to perform the subsequent steps wastefully, but also it is possible to reduce the rate of occurrence of ring-shaped cracks.
[0017]
Preferably, before the sealing step, the method further includes a selection step of measuring the diameter of the neck portion of the glass bulb and selecting the glass bulb. By excluding glass bulbs whose neck diameter is outside the standard, a bulb of stable quality can be manufactured.
[0018]
In the screening step, when the measured diameter of the neck portion is smaller than a predetermined reference value, it is preferable to exclude the glass bulb. When the diameter of the neck portion is small, the inside diameter is also small, and the neck portion is likely to be damaged by contact with the heat shield plate of the stem. Therefore, by selecting and excluding such glass bulbs, it is not only unnecessary to perform the subsequent steps in vain, but also the rate of occurrence of ring-shaped cracks can be suppressed.
[0019]
Preferably, after the annealing step, the method further includes a finishing step of exhausting the inside of the glass bulb, filling a rare gas, turning off an exhaust pipe tip, and attaching a base. Thereby, a bulb with a base can be obtained.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
1 to 3 are views showing an example of a method for manufacturing a light bulb according to the present invention in the order of steps. The method for manufacturing a light bulb according to the present invention will be described with reference to these drawings.
[0021]
First, as shown in FIG. 1A, the outer diameter of the neck portion 3 of the glass bulb 1 made of soda glass is measured using an outer diameter measuring device 13 such as a laser outer diameter measuring device. Then, it is preferable that the glass bulb 1 out of the predetermined tolerance range is selectively excluded. More specifically, it is preferable not to perform a subsequent process except for a glass bulb whose measured value of the outer diameter exceeds the lower limit of the predetermined reference range (that is, the outer diameter is small). This is because a glass bulb having a small outside diameter has a small inside diameter and is likely to be damaged by the heat shield plate of the stem coming into contact with the inner wall surface.
[0022]
Next, as shown in FIG. 1B, the light emitting unit 2 of the glass bulb 1 is applied to the glass bulb having a predetermined neck outer diameter by using, for example, a thickness measuring device 14 using a laser displacement meter. The thickness near the boundary 4 with the neck 3 is measured.
[0023]
As a result of the wall thickness measurement, a glass bulb whose measured value exceeds the lower limit of the predetermined reference range (that is, the wall thickness is thin) is preferably excluded as a product having insufficient strength, and the subsequent process is preferably not performed. This is because it is not suitable for products in the end.
[0024]
In parallel with this, as shown in FIG. 2, a stem 5 provided with a filament coil 6 and a heat shield plate 7 is prepared.
[0025]
Then, as shown in FIG. 3A, the open end of the neck portion 3 of the glass bulb 1 having undergone the step of FIG. 1B is sealed with the stem 5 of FIG. To form
[0026]
Next, as shown in FIG. 3B, the sealed glass bulb 8 is annealed using an annealing apparatus (for example, a gas burner) 9. By this annealing treatment, the distortion remaining in the glass bulb of the bulb finally obtained can be reduced, and the occurrence of cracks can be suppressed. In the annealing process, it is extremely important to appropriately manage the temperature of the glass bulb during the process in order to reduce the residual strain after the process. In the present invention, focusing on this point, the annealing process conditions are optimally set by the following method.
[0027]
As a first technique, the annealing conditions are adjusted based on the measured value of the thickness near the boundary 4 between the light emitting portion 2 and the neck portion 3 of the glass bulb 1 shown in FIG. If the thickness of the glass bulb 1 is different, the heat capacity is different. Therefore, even if the glass bulb 1 is heated and cooled under the same conditions, the temperature of the glass bulb during annealing will be different. Therefore, an appropriate temperature can be maintained and managed by adjusting the setting conditions (for example, the thermal power of the gas burner) of the annealing device 9 according to the thickness. Adjustment of the setting conditions of the annealing apparatus 9 may be performed manually by displaying or recording the thickness measured by the thickness measuring machine 14, or by converting the measured thickness into a signal and applying the signal to the signal. It may be automatically performed based on this.
[0028]
As a second method, the temperature of the glass bulb 8 to be annealed is measured using the annealing temperature measuring device 15, and the annealing conditions are adjusted based on the measured value. Specifically, when the measured temperature of the glass bulb 8 is out of the set temperature range, the set conditions (for example, the thermal power of the gas burner) of the annealing device 9 are adjusted and maintained so as to be an appropriate temperature. Adjustment of the setting conditions of the annealing device 9 may be performed manually by displaying or recording the glass bulb temperature measured by the annealing temperature measuring device 15, or by converting the measured glass bulb temperature into a signal, It may be performed automatically based on a signal.
[0029]
In the present invention, not only when the measured value of the thickness near the boundary 4 between the light emitting part 2 and the neck part 3 of the glass bulb 1 is within a predetermined reference range, but also when the measured value is out of the predetermined reference range, By using the first or second method, the temperature of the glass bulb during the annealing process can be appropriately managed. For example, when a thick glass bulb whose thickness near the boundary 4 exceeds the upper limit of the reference range is treated under normal annealing conditions (gas burner thermal power), the annealing temperature becomes slightly lower than a desired temperature, and the annealing temperature becomes lower. Slow cooling may be inappropriate in the early stages of the process. Therefore, as a first technique, the annealing treatment conditions are adjusted according to the thickness measured in FIG. 1B (for example, the thicker the thickness, the stronger the thermal power of the gas burner), or As a second method, the temperature of the glass bulb is actually measured by the annealing temperature measuring device 15 during the annealing process, and the annealing process conditions are adjusted (for example, the thermal power of the gas burner is increased) according to the measured value, or The first and second techniques are used together. As a result, it is possible to appropriately control the temperature of the glass bulb during the annealing process even for a thick-walled glass bulb in which distortion is likely to remain, thereby suppressing the occurrence of residual distortion and, as a result, the generation of cracks. be able to.
[0030]
The above method can be used to appropriately control the temperature of the glass bulb during the annealing process even for a glass bulb whose measured thickness exceeds the lower limit of the predetermined reference range (that is, the thickness is small). However, thin glass bulbs are liable to crack due to insufficient strength, so it is preferable to exclude them at the stage of measuring the thickness as described above.
[0031]
Next, the gas in the sealed glass bulb 8 after the annealing step is exhausted, a predetermined amount of an inert gas such as krypton, argon, nitrogen or the like is filled, and then the exhaust pipe is chipped off to form the completed glass bulb 10. .
[0032]
Finally, the base 12 is attached, and the light bulb 11 is completed.
[0033]
According to such a method for manufacturing a light bulb of the present invention, particularly in a light bulb provided with a heat shield plate in a glass bulb, when left after completion of the bulb or when the bulb is repeatedly used to turn on and off, the light emitted from the neck of the glass bulb is reduced. It is possible to suppress the occurrence of a ring-shaped rack due to residual strain and temperature stress accumulation at the boundary with the part.
[0034]
Hereinafter, examples of the present invention will be described.
[0035]
In the experiment, a bulb having a total length of 67 mm, a rated voltage of 100 V and 57 W, in which a rare gas such as krypton was sealed in a glass bulb having a maximum diameter of 35 mm using soda glass and an E17 base was provided, was manufactured as shown in FIGS. The steps of D) were sequentially performed, and continuous automatic production was performed using a mechanical device that manufactured at a speed of about 1 second or more per piece.
[0036]
In the glass bulb for a light bulb, the reference range is such that the outer diameter of the neck portion is in the range of 19 ± 0.5 mm, and the thickness near the boundary between the light emitting portion and the neck portion is in the range of 0.60 ± 0.20 mm. . The disc-shaped heat shield plate is made of aluminum, has an outer diameter of 15 mm, and is used for normal production.
[0037]
The sealing temperature between the neck of the glass bulb and the stem was about 900 to 950 ° C. The annealing condition of the sealed glass bulb is changed according to the machine speed. In this embodiment, the temperature is set at about 450 ° C. for about 5 seconds. Both sealing and annealing were performed under the same conditions as in normal production, and both were performed using thermal power generated by a gas burner.
[0038]
First, as shown in FIG. 1 (A), the entire outer diameter of the neck portion 3 of the glass bulb 1 is measured by a laser measuring machine 13, and a glass bulb smaller than the lower limit of the reference range of 18.5 mm (this glass bulb). Is referred to as Group A) and glass bulbs having the lower limit of the reference range or more (this glass bulb is referred to as Group B). Then, for the glass bulbs of groups A and B, the sealing step, the annealing step, and the finishing of FIGS. 3A to 3D are performed without performing the next thickness measurement step (FIG. 1B). The process was performed sequentially to produce a light bulb. With respect to the obtained bulb, the presence or absence of a scratch on the inner surface at the boundary between the light emitting portion and the neck portion of the glass bulb, and the presence or absence of occurrence of a ring-shaped crack at that portion were confirmed.
[0039]
As a result, in the bulb using the glass bulb of the group A, a ring-shaped crack caused by the contact damage due to the heat shield was confirmed in the glass bulb at a rate of about 2.0%, whereas the glass bulb of the group B was confirmed. In the bulb using the bulb, almost no large scratches caused by strong contact of the heat shield plate were observed, slight contact traces with low visibility due to weak contact were slightly scattered, and the rate of occurrence of ring-shaped cracks was zero. It was about 0.02%.
[0040]
Next, in order to further improve the yield of the group B, as shown in FIG. 1 (B), the light emitting unit 2 of the glass bulb of the group B was measured by a thickness measuring device 14 using a laser beam. The thickness near the boundary 4 with the neck 3 is measured, the measured value is displayed and signalized, and the measured value is used to set the glass bulb within the reference range (this glass bulb is referred to as a group C) and the thickness to the reference range. (This glass bulb is referred to as Group D) and a glass bulb whose thickness is smaller than the lower limit of the reference range (this glass bulb is referred to as Group E). Then, for the glass bulbs of Groups CE, the sealing step, the annealing step, and the finishing step of FIGS. 3A to 3D were performed in order to produce a light bulb.
[0041]
As a result, the glass bulbs of Group E, whose wall thickness is thinner than the reference range, are damaged due to lack of strength when transferring the glass bulbs to the equipment that performs each process, during each process, or after completing the bulb. Was found to occur frequently and could not be put to practical use.
[0042]
On the other hand, for the glass bulbs of the group C whose wall thickness is within the reference range, the annealing is performed by the annealing temperature measuring device 15 when the annealing conditions such as the thermal power of the gas burner are set as usual. The temperature of the glass bulb 8 was maintained at 450 ° C. to 480 ° C., and no ring-shaped crack was generated at the boundary between the light emitting part and the neck part of the glass bulb.
[0043]
Next, with respect to the glass bulbs of Group D whose wall thickness is larger than the reference range, the annealing treatment was performed under the same processing conditions as the above-mentioned Group C such as gas burner thermal power. The temperature of the valve 8 was lower by about 30 ° C. than in the case of Group C, and the difference between the sealing temperature of the stem and the temperature at the start of annealing was slightly increased. The rate of occurrence of ring-shaped cracks in the finally obtained bulb was about 0.01%.
[0044]
Therefore, the annealing treatment of the glass bulb of the group D is performed by increasing the gas burner thermal power so that the temperature of the glass bulb 8 measured by the annealing temperature measuring device 15 is in a normal temperature range of 450 ° C. to 480 ° C. As a result, as in the case of group C, no ring-shaped crack was generated at the boundary between the light emitting portion and the neck portion of the glass bulb.
[0045]
Therefore, when the thickness near the boundary 4 between the neck portion and the light emitting portion of the glass bulb falls below the lower limit of the reference range, such a glass bulb is not used, and when the thickness exceeds the upper limit of the reference range. By adjusting the thermal power (increasing the thermal power) in the annealing step to maintain the temperature of the glass bulb within a predetermined range, it is possible to obtain a bulb free of ring-shaped cracks.
[0046]
Further, in the above embodiment, in order to maintain the temperature of the glass bulb during the annealing process in a predetermined range, the temperature of the glass bulb during the processing is actually measured using the annealing temperature measuring device 15 and based on the measured value. The heat power of the gas burner 9 was adjusted. However, as is clear from the above embodiment, the temperature of the glass bulb at the time of annealing has a correlation with the wall thickness near the boundary 4 between the neck portion and the light emitting portion. Even if the thermal power of the gas burner 9 is adjusted on the basis of the measured value of the thickness by the thickness measuring device 14 shown in (1), the temperature of the glass bulb at the time of the annealing process can be similarly maintained within a predetermined range. Of course, the thermal power of the gas burner 9 can be adjusted by using the temperature measurement result obtained by the annealing temperature measurement device 15 and the thickness measurement result obtained by the thickness measurement device 14 in combination, thereby enabling more accurate temperature management. . The heating power of the gas burner can be automatically or manually adjusted based on the temperature measurement result by the annealing temperature measurement device 15 and / or the wall thickness measurement result by the wall thickness measurement device 14.
[0047]
Note that the present invention is not limited to the ratings, dimensions, materials, measuring devices, various conditions, and the like shown in the examples, and can be applied with appropriate changes depending on the bulb to be manufactured.
[0048]
Further, the present invention can be applied without affecting the production speed of a continuous automatic production apparatus widely used in the manufacture of electric bulbs, and is suitable for high-speed production.
[0049]
In the above description, a light bulb with a heat shield is taken as an example, but the present invention can also be applied to a light bulb without a heat shield, thereby producing a bulb with less residual distortion. it can.
[0050]
【The invention's effect】
As described above, according to the method for manufacturing a light bulb of the present invention, the thickness of the boundary between the neck portion and the light-emitting portion of the glass bulb, where ring-shaped cracks are easily generated, is measured, and annealing is performed according to the measured value. Since the processing conditions are adjusted, the temperature of the glass bulb during the annealing process can be appropriately controlled regardless of the thickness of the glass bulb. Therefore, it is possible to prevent the occurrence of residual distortion and to prevent the occurrence of ring-shaped cracks near the boundary between the neck portion of the glass bulb and the light emitting portion.
[Brief description of the drawings]
FIG. 1 is a side view showing a part of a manufacturing process of a light bulb according to the present invention.
FIG. 2 is a side view showing a part of the manufacturing process of the light bulb of the present invention.
FIG. 3 is a side view showing a part of the manufacturing process of the electric bulb of the present invention.
FIG. 4 is a side view showing an example of a conventional light bulb in which a ring-shaped crack has occurred.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Glass bulb 2 Light emission part 3 Neck part 4 Boundary of light emission part and neck part 5 Stem 6 Filament coil 7 Heat shield plate 8 Sealed glass bulb 9 Annealing device (gas burner)
REFERENCE SIGNS LIST 10 Exhausted glass bulb 11 Completed bulb 12 Cap 13 Outer diameter measuring instrument 14 Wall thickness measuring instrument 15 Automatic annealing temperature measuring apparatus 20 Light bulb 21 Glass bulb 22 Light emitting part 23 Neck 25 Cap 27 Heat shield plate 29 Ring crack

Claims (8)

A thickness measuring step of measuring the thickness of the boundary between the neck portion and the light emitting portion of the glass bulb,
A sealing step of sealing the end of the neck with a stem,
An annealing step of annealing the glass bulb after the sealing, and a method for manufacturing a light bulb having this order,
A method for manufacturing a light bulb, comprising: adjusting annealing conditions in the annealing step based on a thickness value measured in the thickness measuring step. 2. The manufacturing method according to claim 1, wherein when the thickness measured in the thickness measuring step is larger than a predetermined reference value, an annealing process condition in the annealing step is changed to increase an annealing temperature. Method. The method for manufacturing a light bulb according to claim 1, wherein in the annealing step, a temperature of the glass bulb during the annealing process is measured, and an annealing process condition in the annealing process is adjusted based on the measured temperature. 4. The method of manufacturing a light bulb according to claim 1, wherein the adjustment of the annealing condition is a thermal power adjustment of a gas burner that heats the glass bulb. 5. The method according to claim 1, wherein in the thickness measuring step, when the measured thickness is smaller than a predetermined reference value, the glass bulb is excluded. The method for manufacturing a light bulb according to claim 1, further comprising, before the sealing step, selecting a glass bulb by measuring a diameter of the neck portion of the glass bulb. The method according to claim 6, wherein in the sorting step, when the measured diameter of the neck portion is smaller than a predetermined reference value, the glass bulb is excluded. The method of manufacturing a light bulb according to claim 1, further comprising a finishing step of exhausting the inside of the glass bulb, filling a rare gas, turning off an exhaust pipe tip, and attaching a base after the annealing step.

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