JP4327417B2 - Melting and sealing method for exhaust pipe of display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of melting and sealing an exhaust pipe for exhausting the inside of a display device such as a plasma display panel (PDP), a field emission display (FED), and a cathode ray tube (CRT).
[0002]
[Prior art]
In a display device such as a PDP, FED, or CRT, it is necessary to exhaust the inside thereof. Therefore, the exhaust pipe provided in the main body of the display device is used to exhaust the inside of the main body. After exhausting, the exhaust pipe is sealed and cut. Therefore, the exhaust pipe is heated to be melted, the exhaust pipe is sealed, and then cut. During this heating, since the inside of the exhaust pipe is in a reduced pressure state, when a part of the exhaust pipe is first melted, the glass of that part is sucked into the inside of the exhaust pipe, and a spherical glass lump is formed in the exhaust pipe. It was easy to do inside. When this lump was formed, the exhaust pipe was partially thick and thin, stress was generated, and the exhaust pipe was liable to crack and leak. Therefore, it has been desired to uniformly heat the exhaust pipe.
[0003]
Conventionally, when a gas burner is used as a heating source, in order to heat the exhaust pipe uniformly, the burner itself has been mechanically swung over about 1 to several millimeters along the diameter direction of the exhaust pipe. .
[0004]
[Problems to be solved by the invention]
However, the operation of swinging the burner is difficult to perform in a narrow work space. In addition, the burner tends to come into direct contact with the exhaust pipe, and the exhaust pipe may be damaged. Moreover, in order to swing the burner mechanically, precise and expensive devices are required, and the mechanical parts of these devices are short-lived, so that the device is easily displaced and maintenance is troublesome. Met.
[0005]
An object of the present invention is to provide a melt sealing method that can easily melt and seal an exhaust pipe uniformly.
[0006]
[Means for Solving the Problems]
In the melt sealing method according to the present invention, the exhaust pipe is heated by two gas burners arranged with a glass exhaust pipe extending from the main body of the display device. The gas burner repeats a first heating state and a second heating state alternately. First heating state is a state in which flame of the gas burner reaches the opposite sides of the exhaust pipe. The second heating state is a state in which the flame of the gas burner has not reached both sides of the exhaust pipe. The repetition frequency is preferably, for example, a low frequency, specifically 1 to 50 Hz. Further, the ratio (duty ratio) of the first heating state to the total time of both heating states is desirably 5 to 80 percent.
[0007]
According to this method, for example, the heat transmitted to the exhaust pipe in the first heating state is transmitted to the other part of the exhaust pipe in the second heating state, and the entire exhaust pipe is uniformly heated. Since such heating and conduction are repeated, the entire exhaust pipe is further heated uniformly. In addition, since it becomes equivalent to continuous heating, even if the repetition frequency is too low or too high, it is desirable to set the frequency as described above. When the duty ratio is 5% or less or 80% or more, it is the same as continuous heating. Therefore, it is desirable to determine the duty ratio as described above.
[0008]
The gas burner is connected to a gas supply pipe, and a gas intermittent means is provided in the middle of the pipe, and the gas burner remains in the pipe between the gas burner and the intermittent means even in the interrupted state of the intermittent means. The interrupting means can be interrupted so that the flame continues with gas .
[0009]
Alternatively, the as flame gas burner is not reached on either side of the exhaust pipe, as well as constantly supplying the gas to the gas burner, as the flame of the gas burner reaches both sides of the exhaust pipe, wherein Increasing the gas in the gas burner can be repeated intermittently.
[0011]
The heating means may have a radiant heat source that generates radiant heat around the exhaust pipe. In this case, a radiant heat intermittent means is provided between the radiant heat source and the exhaust pipe. As heat insulation means for radiant heat, for example, at least one opening for passing radiant heat is provided on the peripheral surface of a cylindrical body arranged concentrically with the exhaust pipe, and the cylindrical body is rotated around the center of the exhaust pipe, It is conceivable to provide a plurality of openings at intervals on the peripheral surface of the body and open and close them intermittently.
[0013]
Heating means, for example, gas burners 4a and 4b are arranged on both sides of the exhaust pipe 2b. These gas burners 4a and 4b have a plurality of flame jets in the vertical direction, respectively, and the flames from these flame jets heat the exhaust pipe 2b.
[0014]
As shown in FIG. 1B, a gas source 8 is connected to the gas burners 4a and 4b via an opening / closing means, for example, an opening / closing valve, specifically, a piezo valve 6. The gas source 8 supplies a mixed gas of a combustion gas, for example, city gas, propane gas, or methane gas, and a combustion support gas, for example, oxygen, air, and support gases such as argon and nitrogen.
[0015]
The piezo valve 6 is repeatedly opened and closed by control means (not shown). Therefore, the gas is introduced into the gas burners 4a and 4b in a pulsed manner. The opening / closing cycle of the piezo valve 6 is, for example, 1 second to 0.02 seconds (1 Hz to 50 Hz). Further, the ratio (duty ratio) of the period during which the gas is supplied for one cycle is selected, for example, from 5 to 80%. Therefore, when the piezo valve 6 is opened, the flame reaches the exhaust pipe 2b, but when the piezo valve 6 is closed, the gas remaining in the pipe between the piezo valve 6 and the burners 4a and 4b The flame will be short enough not to extinguish. These states are alternately repeated according to the opening and closing of the piezo valve 6. That is, the period and the duty ratio are determined so that the gas can be substantially intermittently supplied to the gas burners 4a and 4b. Further, the flow rate of the gas and the mixing ratio of the combustion gas, the support gas, and the support gas are selected so that the tip of the flame reaches the exhaust pipe 2b in the gas supply state.
[0016]
By introducing the gas in a pulse manner in this way, first, as shown in FIG. 2 (a), the tip of each flame 8 reaches the exhaust pipe 2b and heats the reaching portion, and heats these portions. Is reported. That is, it will be in the 1st heating state. Following this, as shown in FIG. 5B, each flame 8 is shortened to such an extent that the flame does not extinguish due to a decrease in the gas flow rate. At this time, the heat previously transmitted to the portion heated by the tip portion of the flame 8 is conducted to the surroundings, and the entire periphery of the exhaust pipe 2b is heated evenly. That is, it will be in the 2nd heating state. Hereinafter, by alternately repeating the first and second heating states, the temperature of the entire periphery of the exhaust pipe 2b gradually increases, and the entire periphery of the exhaust pipe 2b is similarly melted.
[0017]
In the method shown in FIG. 1, the cooling of the exhaust pipe 2b may proceed relatively quickly when the flame 8 is completely intermittent and is short enough that the flame 8 does not extinguish. Therefore, in the second embodiment shown in FIG. 3, the flame is always generated, but the state where the tip reaches the exhaust pipe 2b and the state where it does not reach are alternately taken. Even in a state where the flame tip does not reach the exhaust pipe 2b, the exhaust pipe 2b is heated by the radiant heat, so that rapid temperature cooling does not occur.
[0018]
Therefore, in the method of the second embodiment, gas is constantly supplied from the gas source 8b to the gas burners 4a and 4b. As shown in FIG. 4B, the supply amount and the mixing ratio of the combustion gas and the combustion-supporting gas are determined so that the tip of the flame 8 does not reach the exhaust pipe 2b. Further, the gas burners 4a and 4b are connected to the gas source 8a via the piezo valve 6, and when the piezo valve 6 is opened, as shown in FIG. The supply amount and the mixing ratio of the combustion gas, the combustion support gas, and the support gas are determined so as to heat the portion. Then, even when the piezo valve 6 is closed, the pulse and duty ratio of the piezo valve 6 are controlled so that the state shown in FIG. That is, the state shown in FIG. 4A and the state shown in FIG.
[0019]
The opening / closing period and duty ratio of the piezo valve 6 are set in the same manner as in the first embodiment. The gas source 8b supplies a mixed gas of the combustion gas, the combustion support gas, and the support gas, and the gas source 8a supplies the combustion gas, the support gas, the support gas, or a mixture of two or more of these. The gas source 8b supplies combustion gas, combustion support gas, support gas, or a mixed gas of two or more of these, and the combustion gas, support gas, support gas, or a mixture of two or more of these is supplied. It is also possible to supply the gas source 8a.
[0020]
For example, the gas burners 4a and 4b have five gas outlets each having a diameter of 0.5 mm, the gas supply source 8b is a combustion gas, and a mixed gas of 85% methane and 15% propane is 440 ml per minute. As a support gas, oxygen is regularly supplied at 240 milliliters per minute, the gas source 8a supplies nitrogen as a support gas at a rate of 40 milliliters per minute, and the piezo valve 6 has a cycle of 400 milliseconds ( FIG. 5 (a) shows an exhaust pipe 2b that has been melted, sealed, and cut so that it is opened at 2.5 Hz for 40 milliseconds (duty ratio 10%). As is clear from the figure, since the entire exhaust pipe 2b is heated uniformly, molten glass is not sucked into the exhaust pipe 2b. Accordingly, since there is no great difference in the thickness of the melted, sealed, and cut portions of the exhaust pipe 2b, cracks and leaks are unlikely to occur.
[0021]
FIG. 2B shows an exhaust pipe 2b that has been melted, sealed, and cut by a conventional stationary flame. In the exhaust pipe 2b, the melted, sealed, and cut parts are locally melted and the exhaust pipe 2b is decompressed, so that the melted part is sucked into the exhaust pipe 2b. A spherical lump 3 is generated. As a result, the exhaust pipe 2b has a thick portion and a thin portion, so that cracks and leaks are likely to occur.
[0022]
In FIGS. 4A and 4B, the melted, sealed, and cut portions are thinner than the other portions when the exhaust pipe 2b is It is because it is pulled to the tip side.
[0023]
In the first embodiment, the piezo valve 6 is used as an on-off valve. However, since it can actually be used as a flow control valve, in the first embodiment, the piezo valve 6 supplies the gas burners 4a and 4b. The gas flow rate may be changed in pulses. In the above two embodiments, two gas burners 4a and 4b are used, but the number thereof can be arbitrarily changed.
[0024]
In the above two embodiments, the burners 4a and 4b are used as the heating means. However, other heating means can be used. For example , in the first reference example shown in FIG. 6, a heating means, for example, a resistance heating means, specifically, a resistance heater 10 is used. The resistance heater 10 has a highly resistive coil 10a that generates heat when current is supplied, and the coil 10a is disposed around the entire exhaust pipe 2b as shown in FIG. A pulse power source 12 is provided so as to supply a pulse voltage to the coil 10a. The period of the pulse voltage from the pulse power source 12 is desirably a period corresponding to 0.1 to 50 Hz, and the duty ratio is preferably 5 to 80%.
[0025]
Alternatively, as in the second reference example shown in FIG. 7, for example, an infrared irradiator 14 can be used as the heating means. The infrared irradiator 14 irradiates infrared rays over a wide range, and is disposed close to the exhaust pipe 2b so as to emit infrared rays toward the exhaust pipe 2b. In this state, reflecting means, for example, a reflecting mirror 16 is disposed on the opposite side of the exhaust pipe 2b. This is because the infrared ray from the infrared irradiator 14 passes through the vicinity of the exhaust pipe 2b without being irradiated to the exhaust pipe 2b, and reflects the infrared ray directed to the opposite side of the infrared irradiator 14 to the exhaust pipe 2b side. To overheat. The power source for irradiating the infrared irradiator 14 with infrared rays is the pulse power source 12 as in the first reference example.
[0026]
The resistance heater and infrared irradiator used in the first and second reference examples are sometimes used in the past. However, the method of use is to uniformly heat the whole by heating at a relatively low temperature for a long period of time, and a long time is required for melting and sealing. However, when the resistance heater 10 and the infrared irradiator 14 are heated by the pulse power source 12, the pulse voltage supply is stopped after heating at a relatively high temperature by increasing the value of the supplied pulse voltage. During that time, the heat penetrates. By repeating this, the whole can be heated uniformly in a relatively short time.
[0027]
In the first and second reference examples , in order to heat the entire periphery of the exhaust pipe 2b, in the first reference example , the coil 10a is provided around the entire periphery of the exhaust pipe 2b. In the fourth embodiment, an infrared ray is provided. Although the reflecting mirror 16 is provided in addition to the irradiator 14, when it is necessary to heat locally, the coil 10a is provided only in the portion that needs to be heated, or the portion to be heated by removing the reflecting mirror 16 is desired. Infrared rays may be irradiated only by the infrared irradiator 14.
[0028]
In the first and second reference examples , the pulse power source 12 was used to heat in the form of pulses. However, in the third reference example shown in FIGS. 8A and 8B, radiant heat is constantly generated. The exhaust pipe 2b is heated in pulses while using radiant heat from a radiant heat source. Therefore, a radiation heat source (not shown) is disposed around the exhaust pipe 2b.
[0029]
As the radiant heat source, any radiant heat may be used as long as it supplies radiant heat to the entire circumference of the exhaust pipe 2b. For example, the resistance heater used in the first reference example and the infrared irradiator used in the second reference example and the reflection are used. Can be used with a mirror. Alternatively, a plurality of infrared irradiators may be arranged around the exhaust pipe 2b. However, this radiant heat source radiates radiant heat constantly, as indicated by the dashed arrows in FIG.
[0030]
Between the radiant heat source and the exhaust pipe 2b, a heat insulating means, for example, a cylindrical body 18 made of a heat insulating material is provided. The cylindrical body 18 is disposed concentrically with the exhaust pipe 2b, and radiant heat is radiated to the peripheral surface thereof to block it. The cylindrical body 18 is provided around the center of the exhaust pipe 2b so as to be rotatable in the direction indicated by the solid line arrow in FIGS. A single opening 20 is formed in the peripheral surface of the cylindrical body 18 as shown in FIG.
[0031]
Radiant heat reaches the exhaust pipe 2b through the opening 20. That is, only the portion of the exhaust pipe 2b facing the opening 20 is heated by radiant heat, as shown in FIG. Is transmitted. That is, it is heated in pulses. Such pulsed heating is performed on each part of the exhaust pipe 2b in the entire circumferential direction by rotating the cylindrical body 18. When heating by radiant heat is performed using the opening 20 in this way, the heated exhaust pipe 2b portion is narrowed down, and it is possible to prevent heating even unnecessary portions.
[0032]
Instead of rotating the cylindrical body 18, a plurality of openings are provided at predetermined angles along the circumferential direction of the exhaust pipe 2 b, and a shutter made of a heat insulating material is provided in each opening to open and close it. Alternatively, if the entire periphery of the exhaust pipe 2b is heated, the cylindrical body 18 is not provided with an opening, and is divided into two along the length of the exhaust pipe 2b, and one of the divided members is divided into the other One of the divided members may be driven to reciprocate so that the contact state and the state moved in the length direction of the exhaust pipe 2b by a predetermined distance are alternately repeated.
[0033]
In the above embodiment, the exhaust pipe 2b of the plasma display panel 2 is melt-sealed. However, the present invention is not limited to this. For example, the present invention is used for melt-sealing the exhaust pipe of an FED or CRT. You can also.
[0034]
【The invention's effect】
As described above, according to the present invention, by heating the exhaust pipe in a pulse shape, the exhaust pipe can be made uniform without using expensive and precise equipment for precisely controlling the position of the heating means. It can be easily melt-sealed. In addition, since such equipment is unnecessary, maintenance of equipment used for such a fusion sealing method can be easily performed.
[Brief description of the drawings]
FIG. 1 is a perspective view and a block diagram of an apparatus used for a melt sealing method according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a change state of a flame of a gas burner in the method of FIG.
FIG. 3 is a block diagram of equipment used in a fusion sealing method according to a second embodiment of the present invention.
FIG. 4 is a diagram showing a change state of a flame of a gas burner in the method of FIG.
FIG. 5 is a diagram showing an exhaust pipe that has been melt sealed and cut in the method of FIG. 3 and the conventional method.
FIG. 6 is a block diagram of equipment used in the melt sealing method according to the first reference example of the present invention.
FIG. 7 is a block diagram of an apparatus used in a melt sealing method according to a second reference example of the present invention.
FIGS. 8A and 8B are a partially omitted side view and perspective view of an apparatus used in a fusion sealing method according to a third reference example of the present invention. FIGS.
[Explanation of symbols]
2 Plasma display panel (display device)
2a body 2b exhaust pipe 4a, 4b gas burner

Claims (3)

The first heating in which the flame of the gas burner reaches both sides of the exhaust pipe when the exhaust pipe is heated by the two gas burners arranged across the glass exhaust pipe extending from the main body of the display device. A method for melting and sealing an exhaust pipe of a display device, in which a state and a second heating state in which the flame of the gas burner has not reached both sides of the exhaust pipe are alternately repeated. 2. The method for melting and sealing an exhaust pipe of a display device according to claim 1, wherein the gas burner is connected to a pipe for supplying a gas, and a gas intermittent means is provided in the middle of the pipe. A method for melting and sealing an exhaust pipe of a display device, wherein the intermittent means is intermittently connected so that the flame is continued by the gas remaining in the pipe between the gas burner and the intermittent means.   2. The method for melting and sealing an exhaust pipe of a display device according to claim 1, wherein the gas is constantly supplied to the gas burner so that the flame of the gas burner does not reach both sides of the exhaust pipe, and the gas burner. A method for melting and sealing an exhaust pipe of a display device, wherein the gas burner is intermittently repeated to increase the gas so that the flame reaches both sides of the exhaust pipe.

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