KR20060097769A - Gas discharge panel production method and exhaust pipe sealing off apparatus - Google Patents

Abstract

A method is provided to steadily produce a gas discharge panel, such as a PDP, in which a panel and the top of the barrier ribs are in intimate contact in entirety. First a surrounding unit for the gas discharge panel is formed, then a process for sealing the surrounding unit with a sealing material inserted between two panels at the rim is performed while pressure is adjusted so that pressure inside the surrounding unit is lower than pressure outside. With this construction, the panels constituting the surrounding unit are bonded together while they are pressurized from outside. As a result, a panel and the top of the barrier ribs on the other panel are bonded together while they are in intimate contact in entirety. To fully acquire these effects, it is preferable that the adjustment of pressure starts before the sealing material hardens. During, before, or after the sealing step, an energy such as laser beams or ultrasonic waves may be radiated onto the top of the barrier ribs to bond a panel and the top of the barrier ribs in entirety almost without a gap between them.

Description

GAS DISCHARGE PANEL PRODUCTION METHOD AND EXHAUST PIPE SEALING OFF APPARATUS}

1 is a perspective view of an AC surface discharge PDP of the first embodiment

2 is a block diagram of a display device including a PDP and a circuit block attached to the PDP.

3 is a cross-sectional view of the sealing apparatus used in the sealing process of the first embodiment;

4 is a perspective view of the sealing device shown in FIG.

5A and 5B show a sealing process of the second embodiment

6A and 6B show a sealing process of the third embodiment

Fig. 7 shows the sealing process of the fourth embodiment.

Fig. 8 shows the sealing process of the fifth embodiment;

9A and 9B show a sealing process of a fifth embodiment

Fig. 10 is a perspective view showing the sealing step of the seventh embodiment.

11A and 11B illustrate a method of manufacturing an internal low pressure container used in the sealing process of the seventh embodiment.

12 is a view showing a belt conveyor type heating apparatus used in the sealing process of the seventh embodiment

13A, 13B, and 13C are views showing the state change of the sealing process of the seventh embodiment.

14 shows a belt conveyor heating apparatus used in the sealing process of the eighth embodiment

15 is a view showing a sealing process of the belt conveyor type heating apparatus used in FIG.

16A, 16B and 16C show a sealing process of the ninth embodiment

17 shows a belt conveyor heating apparatus used in the tenth embodiment.

18 is a view showing a sealing process of the belt conveyor type heating apparatus shown in FIG.

19 is a view showing a sealing process of the eleventh embodiment

20A, 20B and 20C show a sealing process of a twelfth embodiment

21A to 21F are front views partially showing specific shapes of the strain relief ribs used in the twelfth embodiment

22A, 22B, and 22C illustrate a process of attaching an upper portion of the barrier rib to the front panel by emitting a laser beam in the thirteenth embodiment.

Fig. 23 is a perspective view showing a specific laser processing apparatus used in the thirteenth embodiment

FIG. 24 shows an example of a laser processing apparatus used in a thirteenth embodiment

Fig. 25 is a perspective view showing an exhaust pipe sealing device used in the fourteenth embodiment.

FIG. 26 is a perspective view showing the exhaust pipe sealing device shown in FIG. 25. FIG.

Fig. 27 is a perspective view showing the exhaust pipe sealing device of the fourteenth embodiment.

28 is a view showing a change of the exhaust pipe sealing device of the fourteenth embodiment

29 is a view showing a change of the exhaust pipe sealing device of the fourteenth embodiment

30 is a view showing a change of the exhaust pipe sealing device of the fourteenth embodiment.

The present invention relates to a method for producing a gas discharge panel, in particular, to a method for producing a gas discharge panel and an exhaust pipe sealing device.

Recently, as the demand for high-definition large screens such as high-definition TVs increases, displays suitable for such TVs, such as cathode ray tube (CRT), liquid crystal display (LCD), and plasma display panel (PDP), have been developed.

CRT is widely used as a TV display and has excellent resolution and image quality. However, its depth and weight increase as the screen size increases. Therefore, CRTs are not suitable for large screens larger than 40 inches. LCDs consume less electricity and operate at lower voltages. However, the production technology of large LCD screens is difficult and the viewing angle of the LCD is limited.

PDPs, on the other hand, have large screens with low depth, and 50-inch PDP products are already being developed.

PDPs are classified into two types: direct current (DC) and alternating current (AC). Currently, AC type PDP is mainly used because it is suitable for large screen.

Typical AC type PDPs, which are AC surface emitting PDPs, consist of a front panel and a rear panel with electrodes attached respectively, so that the electrodes on both sides of the panel are in contact with each other. The space between the front panel and the rear panel is divided into multiple spaces per barrier rib. Multiple spaces between these barrier ribs are filled with discharge gas and any one of red, green and blue phosphors. The driving circuit applies a voltage to each electrode to cause discharge, and ultraviolet rays are emitted. Ultraviolet light excites the fluorescent material. The excited phosphors emit red, green and blue light. The emitted light of these colors forms an image on the screen.

Typically, the PDPs are manufactured in the following order. Barrier ribs are disposed on the surface of the rear panel, a phosphor layer is formed in the grooves between the barrier ribs, and the front panel is a surrounding unit (hereinafter referred to as a 'sealing unit') on the top of the barrier ribs (front panel). And the rear panel is adhered between the inner space), the edges of the sealing unit, that is, the front panel and the rear panel are sealed with a sealing material, and the gas is evacuated from the inner space for vacuum generation, and the inner space Is filled with discharge gas.

The sealing material usually becomes a low melting glass that is softened by heat. The mixture of low melting glass and pressure sensitive adhesive is applied to the dispenser or the edge of either the front substrate or the back substrate before the sealing glass is constructed by placing the panel. In the sealing process, the panel is heated by heating the panel to a temperature higher than the softening point of the low melting point glass, and the edge of the sealing glass covering the applied sealing material and the outermost region is fixed with a clip or the like.

However, PDPs produced by this method have a gap between the barrier glass and the front panel. The gaps are each different for each barrier rib. This reason is as follows. (1) The deviation of the barrier ribs in the height occurs in the process of forming the barrier ribs in which the material of the barrier ribs is disposed on the rear substrate. (2) The panel and barrier ribs are deformed in the heating step of the barrier ribs, the fluorescent material, the electrode and the dielectric layer, and the temporary firing step of the sealing glass layer performed before the sealing step.

Moreover, in the sealing process of the PDP, the edges of the front panel and the rear panel are aligned with the positions where the panels are in contact with each other and then fixed with a clip-like fastener to prevent displacement of the panel. However, such fixing causes a gap between the top of the barrier rib and the front panel at its center due to the lever acting as the point of the barrier rib. In addition, the pressure by the fixtures is different, so often a nonuniform gap occurs.

When manufacturing a PDP through the sealing process having the gap, noise is often generated between the barrier ribs and the panel due to vibration of the panel which is often caused by crosstalk when the PDP is activated or caused by discharge or the like.

Japanese Utility Model Publication No. 1-113948 discloses a technique in which a low melting point cage is applied on top of a barrier rib before the front panel and the rear panel are placed face to face and adhered to each other. Using this technique, if the front panel sticks to the front panel over the entirety of the barrier ribs, the sealing unit will not expand even if the discharge gas is charged into the inner space at high pressure. In addition, because the gap between the barrier ribs and the front panel is not filled with sealing material, this technique solves the problem of vibration.

In practice, however, it is difficult to stick the top of the barrier ribs. The top of the barrier rib often remains unattached. Therefore, this technique is insufficient to solve the problem of pressure. In particular, when there is a deviation of the barrier ribs in the size on the rear panel, many parts remain unattached. In this case, sufficient resistance to pressure cannot be obtained.

There is another conventional method in which the front and rear panel sets are heated for sealing and a weight such as stone is applied at the center thereof. However, according to this method, the weight on the panel is also heated so much energy is required for heating. The heating temperature of the sealing unit is not the same. It is difficult to use this technique for large screen PDPs.

 There is another condition in the manufacture of the panel. Typically, a vacuum pump or discharge gas cylinder is connected to the exhaust pipe attached to the sealing unit. The exhaust pipe is subsequently chiped off by a burner or heater. A reliable method of chipping off the exhaust pipe is desirable.

It is an object of the present invention to provide a method for stably manufacturing a gas discharge panel such as a PDP in which the upper part of the panel and the barrier ribs are in contact with each other in a safe state.

The gas discharge panel manufacturing method of the present invention for solving the above problems is a gas discharge panel manufacturing method comprising a sealing step of melting and sealing the exhaust pipe attached to the sealing unit is composed of a pair of panels facing each other, And a second step of disposing a heating element at a position away from the exhaust pipe and a second step of causing the heating element to heat the exhaust pipe.

Preferably, in the first step, the heating element is arranged at a position away from the exhaust pipe by a limiting member.

The exhaust pipe sealing device of the present invention is an exhaust pipe sealing device that melts and seals an exhaust pipe attached to a sealing unit in which a pair of panels are disposed to face each other, and is attached to the exhaust pipe and heated at a predetermined distance away from the exhaust pipe. And a heating element holding means for holding the element.

In addition, the exhaust pipe sealing device of the present invention is an exhaust pipe sealing device for melting and sealing the exhaust pipe attached to the sealing unit constituted by a pair of panels facing each other, comprising a cylindrical body in which a heating element is held therein, The cylindrical body is characterized in that it comprises a heating unit having an inner diameter larger than the outer diameter of the exhaust pipe, and a limiting member for limiting the position of the heating unit such that the heating unit is disposed around the exhaust pipe at a predetermined distance from the exhaust pipe.

Preferably, the limiting member may be divided into two parts by a plane passing through the central axis of the exhaust pipe.

Preferably, the limiting member is disposed at two or more places along the exhaust pipe between the heating unit and the exhaust pipe.

Preferably, the heating unit further comprises an insulator, and the heating element is wound in an insulator in a coil shape.

(Example)

<General structure and manufacturing method of PDP>

1 is a perspective view of an AC surface discharge type PDP in this embodiment. 2 illustrates a structure of a display device including a PDP and a circuit block attached to the PDP.

The PDP is a front panel composed of a front glass substrate 11 together with a discharge electrode 12 (classified as a scan electrode 12a and a sustain electrode 12b), a dielectric layer 13, and a protective layer 14. 10, and a back panel 20 composed of a back glass substrate 21 together with an address electrode 22 and a dielectric layer 23. The front panel 10 and the rear panel 20 are arranged to face each other with respect to the space between the discharge electrode 12 and the address electrode 22.

The central area of the PDP is used to display an image. In the central region, the space between the front panel 10 and the rear panel 20 is divided into a plurality of discharge spaces 30 by barrier ribs 24 formed in the strip. Each discharge space is filled with discharge gas. The phosphor layer 25 is formed on the rear panel 20 so that each discharge space 30 has a phosphor layer of any color among red, green, and blue. The phosphor layer is arranged repeatedly in the order of the colors.

In the panel, the discharge electrode 12 and the address electrode 22 are each formed in a strip, the discharge electrode 12 is orthogonal to the barrier rib 24, and the address electrode 22 is parallel to the barrier rib 24. .

A cell having any color among red, green, and blue is formed at each intersection of the discharge electrode 12 and the address electrode 22.

The dielectric layer 13 with the layer of dielectric material covers the entire surface of one side of the front glass substrate 11 including the discharge electrodes 12. The dielectric layer 13 is generally made of a low softening point glass containing lead (Pb) as the main component, but it is a stack of low softening point glass containing bismuth (Bi) as the main component or a low softening point glass containing lead as the main component and It may be made of low softening point glass containing bismuth as a main component.

The protective layer 14 composed of magnesium oxide (MgO) is a thin layer covering the entire surface of the dielectric layer 13. Dielectric layer 13 is also mixed with TiO ₂ particles for a layer that functions as a visible light reflecting layer. Barrier ribs 24 made of glass material are formed to protrude upward from the surface of the dielectric layer 23 of the rear panel 20.

The front panel 10 and the rear panel 20 are adhered by sealing a material on the edge of the PDP. The top of the barrier rib 24 and the front panel 10 are in contact with each other or almost completely stick together. Hereinafter, the PDP manufacturing method will be described.

How to manufacture the front panel

The discharge electrode 12 is formed on the front glass substrate 11. The dielectric layer 13 is formed to cover the discharge electrode 12. The front panel 10 is completed after the protective layer 14 made of magnesium oxide (MgO) is formed on the dielectric layer 13 by vacuum deposition, electron beam deposition, or chemical vapor deposition.

The discharge electrode 12 is formed by first applying a paste for the silver (Ag) electrode to the front glass substrate 11 by screen printing and then firing the paste. Optionally, the discharge electrode 12 first forms a transparent electrode composed of ITO (Indium Tin Oxide) or SnO ₂ , and then forms a silver electrode as described above or a photolithography method on the transparent electrode. It can be formed by forming Cr-Cu-Cr.

The dielectric layer 13 has a main component (for example, 70% of lead oxide (PbO), 15% of boron oxide (B ₂ O ₃ ), and silicon oxide (SiO ₂ ) together with screen printing. ) Is formed by applying a paste containing a glass material containing lead, and then firing the applied paste.

How to manufacture the rear panel

The address electrode 22 is formed on the rear glass substrate 21 in the same manner as the discharge electrode 12 by screen printing.

Dielectric layer 23 is formed by first applying a glass material mixed with TiO ₂ particles and then firing the applied material.

Barrier ribs 24 are formed by overlay coating a paste on barrier ribs together by screen printing and then firing the coated paste. Optionally, the barrier ribs 24 will be formed by applying a glass paste for barrier ribs to the entire surface of the rear glass substrate 21 and trimming the paste by sand blasting the part which does not form the barrier ribs.

Phosphor layer 25 is formed between barrier ribs 24. In general, the phosphor layer 25 is formed by applying a phosphor paste containing phosphor particles for three colors by screen printing and firing the applied paste. Optionally, the phosphor layer 25 is applied by injecting the phosphor ink into the grooves between the barrier ribs along the groove while continuously spraying the phosphor ink from the nozzle, and then firing the applied ink to remove the solvent or adhesive contained in the phosphor ink. Will be formed. Each color phosphor ink is a mixture of phosphor particles of any color, such as adhesives, solvents, and dispersants, adjusted to have a suitable viscosity.

The following is a specific example of the fluorescent material used in the present embodiment.

Blue phosphor BaMgAl ₁₀ O ₁₇ : Eu ^{2 +}

Green phosphor BaAl ₁₂ O ₁₉ : Mn, or Zn ₂ SiO ₄ : Mn

Blue fluorescent substance _{(Y X Gd 1 -X) BO} 3: Eu 3 +, or YBO ₃ : Eu ^{3 +}

In this embodiment, the height of the barrier rib matching the 40-inch VGA and the high-definition TV is set to 0.1-0.15 mm, and the pitch of the barrier rib is set to 0.15-0.36 mm.

How to fill with seal, exhaust gas and discharge gas

The front panel and the back panel are formed as described above and then adhered together.

In this sealing process, the front panel 10 and the rear panel 20 put the sealing material together between their edges to form a sealing unit. The panels are glued together by a sealing material. If necessary, the pressure-sensitive adhesive is applied to the upper portion of the barrier ribs 24 of the rear panel 20 in advance.

Materials that soften by a given energy, such as heating, are used as sealing materials. Generally low melting glass is used as the sealing material. With low melting glass the panels are heated at a temperature higher than the softening point of the glass and the panels are cooled to stick together by the cooled glass.

In the sealing process, the front panel 10 and the rear panel 20 are given the same pressure from the outside by the panels forming a pressure difference between the external pressure and the sealing unit. This allows the panels to stick together while the top and rear panels of the barrier ribs 24 are in contact or in perfect contact with each other.

After the sealing step, high vacuum (e.g., 8 x 10 ^-7 torr) is generated inside to exhaust the internal space, and the impurities retained by the adsorption action on the inner surface of the sealing unit are exhausted (vacuum exhausting step).

The inner space of the sealing unit is then filled with a discharge gas (that is, He-Ne or Ne-Xe inert gas) with a predetermined pressure (discharge gas filling process). PDP is completed by this process.

In this embodiment, Xe in the discharge gas constitutes 5% by volume, and the pressure for filling the discharge gas is in the range of 500-800 torr.

The PDP is activated for displaying an image by a circuit block attached to the PDP as shown in FIG.

The first to tenth embodiments of the present invention will be described in detail the sealing, exhaust and discharge gas filling process as follows.

First embodiment

In this embodiment, the sealing process is performed while the gas is exhausted from the inner space of the sealing unit by the vacuum pump.

3 is a cross-sectional view of the sealing device 50 of the present embodiment. 4 is a perspective view of the sealing device 50 shown in FIG.

The sealing device 50 includes a melting furnace 51 for housing and heating the sealing unit 40 in which the front panel 10 and the rear panel 20 are put together; And it consists of a vacuum pump 52 located outside the melting furnace 51.

The melting furnace 51 is heated by the heater 55. It is possible to set the internal temperature of the furnace 51 for the required degree of control.

The sealing process proceeds using the sealing device 50 as follows.

As shown in Figs. 3 and 4, the exhaust port 21a is formed in advance in the edge of the rear panel 20 and outward of the display area.

The paste mixed with the sealing material is applied to either or both edges on the surface where the front panel 10 and the back panel 20 contact each other. The applied paste is baked to form the sealing layer 41. In this example, low melting glass having a lower softening point than barrier ribs 24 and dielectric layer 23 is used as the sealing material.

For example, the low melting glass paste comprises 80% low melting glass raw material (softening point is 370 ° C.), 5% ethyl cellulose tackifier, and 15% isoamyl acetate. The sealing layer 41 may be formed by applying a paste by using a dispenser. The front panel 10 and the rear panel 20 are properly positioned in contact with each other and put together to form a sealing unit 40. The edge of the sealing unit 40 is fixed with a clip 42 to prevent the panels from being moved.

The sealing unit 40 is located inside the melting furnace 51. The pipe 26 is attached to the exhaust port 21a to adhere the sealing unit 40 and the vacuum pump 52. It is preferred that the pipe 26 is secured to the back panel 20 by a tool that secures it, such as a clip (not shown).

In this embodiment, the front panel 10 is positioned below the rear panel 20 to facilitate the attachment of the pipe 26. However, the positions of the panels can be reversed. In addition, the front panel 10 and the rear panel 20 will be disposed perpendicular to the melting furnace as long as it is firmly fixed such that it is not moved.

The pipe 26 is made of glass resistant to the sealing temperature. The pipe 26 widens upward from the exhaust port 21a of the sealing unit 40, bent at a central point, and projects outward from the melting furnace 51 through a hole 51a formed in the wall surface of the melting furnace 51. It becomes wider. The pipe 26 protrudes from the edge (shown as an adhesive edge) that adheres the exhaust port 21a, and the diameter of the adhesive edge is larger than the diameter of the exhaust port 21a.

The adhesive 26a is previously injected between the adhesive edge of the pipe 26 and the back panel 20 so that they are tightly sealed. In this embodiment, such a material is used for both the adhesive 26a and the sealing layer 41.

The end of the pipe 26 is adhered to the vacuum pump 52.

The interior of the furnace 51 is heated at a temperature slightly higher than the softening point of the sealing material (ie 450 ° C.). The internal temperature of the furnace 51 is maintained for 10-30 minutes at the sealing temperature. The interior of the furnace 51 is then cooled until the temperature is below the softening point of the sealing material. The front panel 10 and the rear panel 20 are adhered by this process. During the sealing process, the gas is exhausted from the sealing unit 40 by the vacuum pump 52. The evacuation of the gas preferably begins after the interior of the furnace 51 has reached the softening point of the sealing material. This is because the sealing is not high at the edge between the front panel 10 and the rear panel 20 until the inside of the melting furnace 51 reaches the softening point of the sealing material, which is that once it reaches the softening point, the adhesive 26a softens to tightly seal the pipe 26 and the exhaust port 21a at the edges, like the front panel 10 and the rear panel 20. Therefore, when the gas is exhausted from the sealing unit 40 after these parts are tightly sealed, the reduced internal pressure and high vacuum (water torr) of the sealing unit 40 are generated.

The front panel 10 and the rear panel 20 maintain the pressure uniformly from the outside after the gas is exhausted from the inner space of the sealing unit 40. The exhaust of the gas by the vacuum pump 52 is adjusted so that the internal pressure of the sealing unit 40 is reduced at a rate of about 5 torr / minute. When the front panel 10 and the rear panel 20 are uniformly maintained in pressure from the outside, the upper portion of the barrier rib 24 and the front panel 10 on the rear panel 20 are shown in FIG. They stick together while they are correctly connected in perfect condition. When the interior of the furnace is cooled in this state, the sealing material will also cool down below its softening point, as a result of the sealing of the sealing unit 40. Therefore, in the sealing unit 40 after the sealing process, the upper portion of the barrier rib 24 and the front panel 10 are completely in contact with each other unconditionally.

The pipe 26 and the back panel 20 are also tightly sealed by the hardened furnace 26a.

The clip 42 is moved after the sealing of the sealing unit 40 is completed and a vacuum evacuation process is performed in the next step.

In the vacuum evacuation process, the sealing unit 40 is placed in a furnace for vacuum evacuation, the vacuum pump is adhered to the pipe 26, and the interior of the furnace is less than the softening point of the sealing material for a certain period (ie 1 hour). It is maintained at a slightly lower exhaust temperature (ie 350 ° C.).

In the discharge gas filling process of the next step, the discharge gas cylinder is adhered to the pipe 26, the discharge gas is stored in the interior space of the sealing unit 40 until the internal space becomes below the overpressure (i.e. 400 torr). Supplied. The exhaust port 21a is sealed when the base of the pipe 26 is melted by a burner or heater to be trimmed. The above procedure may be replaced with another that is susceptible to a sealing process, a vacuum evacuation process, and a discharge gas filling process in a device in which the sealing unit 40 is heated. For example, in the sealing device 50, a cylinder for supplying the discharge gas is provided so that it can stick to the pipe 26. Then, after the sealing process, the sealing unit 40 is placed in the melting furnace 51. The furnace 51 is cooled for the exhaust temperature, and then the gas is exhausted from the sealing unit by the vacuum pump 52. Moreover, the cylinder can stick to the pipe 26 for supplying the discharge gas. The procedure can also be replaced with another one in which a continuous heating device is used to continuously perform the sealing process, the vacuum evacuation process, and the discharge gas filling process. For example, like a sealing unit, a vacuum pump and a discharge gas cylinder are stacked on a cart that can be moved in a continuous furnace. It enables a vacuum pump to charge the discharge gas by the discharge gas cylinder and the gas exhausted from the seal unit by the seal unit while the seal unit is continuously heated in the furnace.

Effect of this method

In the prior art in which the edge of the sealing unit 40 is fixed by the clip without a pressure difference between the external pressure and the interior of the sealing unit 40, the central portion of the sealing unit 40 is not pressurized. As a result, the top of the front panel 10 and the barrier ribs on the back panel 20 stick together with them partially separated from each other. In contrast, in the present embodiment, the sealing layer 41 is cured while the front panel 10 and the rear panel 20 are uniformly maintained in pressure from the outside. This makes it possible to stick with little space between the front panel 10 and the top of the barrier ribs.

Therefore, the manufacturing method of the present embodiment facilitates the production of PDPs having excellent display characteristics that hardly generate vibration when they are activated.

To achieve this effect, the vacuum pump 52 will be activated to cause a difference between the external pressure and the interior of the sealing unit 40 before the softened sealing layer 41 begins to cure. However, it is not necessary to operate the vacuum pump 52 from the beginning to the completion of the sealing process. For example, it is possible to obtain the effect of generating a pressure difference even if the vacuum pump 52 is activated after the sealing layer 41 is softened.

Moreover, the front panel 10 and the rear panel 20 maintain pressures to each other because of the difference between the internal pressure and the external pressure when the panels are adhered while the sealing unit 40 is sealed at different pressures. As a result, the pressure exerted by the clip 42 required to prevent movement of the panels can be less than that of the conventional method.

It will be noted here that the clips 42 need not necessarily be used to prevent movement of the front panel 10 and the back panel 20. However, the use of clips ensures the prevention of movement. Moreover, the clips 42 also maintain a constant pressure of the sealing layer 41 inserted between the panels of their edges. Because of this pressure, the sealing material is sprayed evenly over the edges as it softens. This seals the edge tightly.

Other materials can be used for the adhesive 26a and the sealing layer 41. However, when the same low melting glass is used, as in this embodiment, the sealing layer 41 and the pressure-sensitive adhesive 26a are softened and cured at the same timing. This means that the sealing unit 40 sealing the pipe 26 and the exhaust port 26a of the rear panel 20 at the same time is sealed tightly.

Example of Variant

In this embodiment, the low melting glass is used as the adhesive 26a, and the pressure is used inside the sealing unit 26a while the adhesive 26a is softened. Here, the adhesive 26a flows into the exhaust port 21a, and the sealing between the pipe 26 and the air exhaust port 21a is broken.

In order to prevent the above problem, crystalline glass which is determined at a lower temperature than the sealing layer 41 may be used. The glass is typically PbO-ZnO-B ₂ O ₃ fritglass.

The crystallizes and hardens as soon as it is heated to fluidize the crystalline glass, but the glass does not soften even if it is heated again at the initial crystalline temperature.

Therefore, the above problem related to the sealing is solved by slowly heating the sealing unit 40 using the crystal glass as the adhesive 26a. In this way the crystal glass is solidified before the sealing layer 41 is softened.

The same effect as the pressure-sensitive adhesive 26a is obtained using glass having a softening point much higher than that of the sealing layer 41.

This problem can be solved by connecting the pipe 26 to the exhaust port 21a of the back panel 20 using a material that does not soften at the temperature of the adhesive panel in advance as the adhesive 26a (significantly than the sealing layer 41). Glass or ceramic adhesives with high softening points).

Second embodiment

This embodiment differs from the first embodiment in that the sealing units 40 are formed by positioning the panels 10 and 20 so as to face each other. As shown in FIGS. 5A and 5B, in the sealing process an outer sealing layer 43 is further formed between the panels 10, 20 at the edges.

In this way, if the sealing of the sealing layer 41 has a defect, the defect is covered by the outer sealing layer 43 so that the sealing process is much safer.

In addition, the outer sealing layer 43 reduces the gap between the top of the barrier ribs and the front panel 10.

Formation of the outer seal layer 43 provides another effect.

For example, before softening, the outer sealing layer 43 holds the panels 10 and 20 to prevent the panels from displacing. In addition, the sealing degree of the inner space is maintained even before the sealing layer 41 or the outer sealing layer 43 is softened. As a result, pressure may be applied to the panels 10 and 20 by dividing the vacuum pump 52 to exhaust the gas from the interior space.

The same material is preferably used for the sealing layer 41 and the outer sealing layer 43 in order to achieve this effect. For example, a paste including a sealing material (low melting glass) used as the material of the sealing layer 41 is applied to the outside of the sealing layer 41 of the sealing unit 43 to form the outer sealing layer 43. do.

In addition, the sealing layer 41 is formed by apply | coating a ceramic adhesive.

Third embodiment

As shown in FIG. 6A, the semi-sealing agent inlet rib 44 is formed in the region of the sealing layer 41 formed at one end on either the front panel 10 and the rear panel 20 or two. This embodiment is different from the first embodiment in that respect.

By forming the semi-sealing material inlet rib 44 in advance, the sealing layer 41 is prevented from entering the display area when the sealing layer 41 is melted during the sealing process, and the pressure of the sealing unit 40 is higher than the external pressure. low.

It is preferable that the semi-sealing material inlet rib 44 as the barrier rib 24 is about the same height. This occurs when the gap 44 is higher than the barrier rib 24 and a gap is created between the front panel 10 and the top of the barrier rib 24 and when the rib 44 is much lower than the barrier rib 24. This is because the inflow preventing effect of the layer 41 cannot be described.

As shown in FIG. 6B, an easy way to form the semi-sealing material inlet rib 44 is to form the barrier material 24 on the rear glass substrate 21 of the rear panel 20 simultaneously with the same material. .

Fourth embodiment

The present embodiment differs from the first embodiment in that the pressure is pressurized from the outside of the sealing unit 40 to generate a difference between the inside and the outside of the sealing unit 40 during the sealing process.

On the other hand, in the first embodiment, the gas is exhausted from the inner space of the sealing unit to reduce the internal pressure.

In order to implement the above, the vacuum pump 52 is excluded from the sealing device 50 of the present embodiment, but as shown in FIG. 7, the compression pump 53 is hermetically sealed 51 which can be sealed by sealing in the present embodiment. ) Is attached.

In the sealing process of this embodiment, the sealing unit 40 of one end of the pipe 26 which opens air to the outside while the inside of the melting furnace 51 is pressurized by the compression pump 53 is the melting furnace 51 Heated and sealed at

As described above, the method of sealing the sealing unit 40 can provide the same effect as the first embodiment because the sealing unit 40 is sealed while receiving a high pressure from the outside. Even more particularly, the sealing process is carried out while the inner space of the sealing unit 40 is actually maintained at atmospheric pressure and the outside of the sealing unit 40 is a high pressure.

Fifth Embodiment

In this embodiment, the sealing unit 40 is sealed using the same sealing device 50 as the fourth embodiment.

However, as shown in Fig. 8, the pipe 26 of the present embodiment is linear, and one end of the pipe 26 does not penetrate the melting furnace 51 while being sealed.

9A shows the state of the sealing unit 40 in which the sealing unit 40 is sealed by the sealing layer 41 before the sealing layer 41 is softened during the sealing process and FIG. 9B shows that the sealing layer 41 is softened. It shows the state after being. The sealing process of this embodiment will be described in detail with reference to FIGS. 9A and 9B.

First, the sealing layer 41 is softened by heating the sealing unit 40 in the melting furnace 51 without operating the pump pressure 53 while the inside of the melting furnace 51 is maintained at atmospheric pressure.

As shown in FIG. 9A, the gas flows in or out of the sealing unit 40 before the sealing layer 41 is softened. Therefore, when the sealing layer 41 is softened, the pressure in the inner space is almost equal to atmospheric pressure.

After the sealing layer 41 and the adhesive 26a are softened, the compression pump 53 operates to pressurize the inside of the melting furnace 51.

As shown in FIG. 9B, after the sealing layer 41 and the adhesive 26a are softened, gas flow is blocked between the inside and the outside of the sealing unit 40. When the inside of the melting furnace 51 is pressurized under the above state, the inner space of the sealing unit 40 becomes almost atmospheric pressure, while the outside of the sealing unit 40 is at a much higher pressure than the inside.

When the inside of the furnace 51 is cooled at such a high pressure, the sealing layer 41 is cured and the sealing unit is sealed while being pressurized from the outside.

As can be understood from the above, the method of this embodiment provides the same effects as in the first embodiment.

The sealing process follows a vacuum evacuation process in which one end of the pipe 26 is blocked and opened, the vacuum pump is connected to one end, and the gas is evacuated from the internal space by the vacuum pump to generate a vacuum.

Sixth embodiment

This embodiment is basically the same as the fifth embodiment except that the internal pressure of the sealing unit 40 is reduced so that the external pressure of the sealing unit 40 is adjusted to atmospheric pressure, and in the fifth embodiment, the sealing unit The external pressure of the 40 is increased, and the internal pressure of the sealing unit 40 is maintained at atmospheric pressure to generate a difference between the inside and the outside of the sealing unit 40.

 Except that the compression pump 53 is replaced by a vacuum pump, the sealing device 50 of the present embodiment has a configuration as shown in FIG.

In the sealing process of this embodiment, the first vacuum pump is operated to reduce the pressure in the melting furnace 51, and the sealing unit 40 softens the sealing layer 41 while the inside of the melting furnace 51 is kept at a low temperature. Heated to

Before the sealing layer softens, the gas flows in and out of the sealing unit 40. As a result, the inner space of the sealing unit 40 is also at a reduced pressure when the sealing layer 41 is softened.

After the sealing layer 41 and the pressure-sensitive adhesive 26a are softened, the vacuum pump is stopped so that the internal pressure of the melting furnace 51 increases to atmospheric pressure. In this step, the gas flow between the inside and outside of the perimeter 40 is blocked by the softening material.

As a result, the external pressure of the sealing unit 40 is higher than the internal.

When the internal pressure of the melting furnace 51 is cooled under the above conditions, the sealing layer 41 is cured and the sealing unit is sealed while the melting furnace is pressurized from the outside.

As can be understood from the above description, the method of the present embodiment also provides the same effects as the fifth embodiment.

Seventh embodiment

In the present embodiment, the inner container which is below the low pressure is connected to the sealing unit so that the sealing unit is sealed while gas is exhausted from the sealing unit of the container which lowered the internal pressure of the sealing unit.

10 is a perspective view showing how the sealing unit 40 is sealed by the method of this embodiment.

In the first embodiment, the exhaust port 21a is previously opened at the edge of the rear panel 20 outside the display area. In this embodiment, not only the exhaust port 21a but also the exhaust port 21b is opened at the edge.

As a first embodiment, the sealing layer 41 is formed at the edge of the front panel 10 and the rear panel 20 or any one of the surfaces facing each other. The front panel 10 and the rear panel 20 are placed in suitable positions to face each other and are joined to form the sealing unit 40. The edge of the sealing unit 40 is fixed by the clip 42 so that the panel is not displaced.

The low internal pressure container 70 is attached to the exhaust port 21a of the sealing unit 40. The pipe of the fifth embodiment is attached to a sealed end of the exhaust port 21b.

As the pipe 26, the low internal pressure container 70 is made of glass resistant to the sealing temperature, and is connected to the connector 72 protruding from the container body 71 to connect the container body 71 and the exhaust port 21a. It is composed. The container body 71 is hermetically sealed by a gas flow blocking layer 73 (FIG. 13A) formed inside the connector 72 that blocks the flow of gas, and the inside of the container 71 is maintained at a reduced pressure. do.

The adhesive 74 is previously applied to the joint of the connector 72 and the exhaust port 21a of the rear panel 20.

The adhesive 26a is previously applied to the joint of the pipe 26a and the air hole 21b of the rear panel 20. The bond is hermetically sealed by an adhesive. In this embodiment, the material used for the sealing layer 41 is also used for the adhesives 26a and 74.

The material used for the softening point of the sealing layer 41 or the low melting glass is somewhat higher than the sealing layer 41 used for the gas flow barrier layer 73 and the sealing layer 41 and the adhesives 26a and 74 soften. Layer 73 then softens almost simultaneously.

Now, the method of generating the low internal pressure container 70 is described in detail with reference to Figs. 11A and 11B.

Container body 71 and connector 72 are manufactured using techniques used to process glassware, such as flasks. Note that the container body 71 has an exhaust pipe 72a that is used to exhaust the gas to generate a vacuum except for the condenser 72.

As shown in FIG. 11A, the connector 72 is filled with a paste comprising low melt glass as the material of the gas flow blocking layer 73. The gas flow barrier layer 73 is formed by softening a paste using a heater such as a gas burner and then curing again.

As shown in Fig. 11B, the vacuum pump is connected to the exhaust pipe 72a so that the gas is exhausted from the container body 71 at the degree of vacuum using the vacuum pump.

As shown in Fig. 11C, the exhaust pipe 72a is chipped off using a gas burner with a vacuum pump connected to the exhaust pipe 72a while maintaining the degree of vacuum in the container body 71.

In this process, the container of the low internal pressure in which the container body 71 has a predetermined degree of vacuum is completed.

12 shows a belt conveyor type heating apparatus used to seal the sealing unit 40 in this embodiment.

The belt conveyor type heating device 60 includes a melting furnace 61 for heating a panel; A conveyor belt 62 for conveyor of the sealing unit 40; A plurality of heaters 63 are displaced in the furnace 61 along the direction of the conveyor.

The temperature at the multiple points between the inlet 64 and the outlet 65 is controlled by the multiple heaters 63. With the above configuration, the sealing unit 40 is heated or cooled to the desired temperature pile.

13A to 13C show a state change of the sealing unit 40.

The low internal pressure container 70 and the sealing unit 40 of the pipe 26 are sealed using the following heating device 60.

The sealing unit 40 is located at the conveyor belt 62 of the heating device 60 and is transferred from the melting furnace 61. The sealing unit 40 is heated to a sealing temperature set at a temperature slightly higher than the softening point of the gas flow barrier layer 73 while being conveyed in the melting furnace 61. For example, the speed of temperature increase in heating is 10 ° C./min.

When the temperature of the sealing unit 40 is lower than the softening point of the sealing layer 41, the gas flows in or out of the sealing unit 40 via the sealing layer 41. On the other hand, as shown in Fig. 13A, the degree of vacuum in the container body 71 is maintained since the gas flow from the inside to the outside is blocked by the gas flow blocking layer 73.

When the temperature of the sealing unit 40 reaches the softening point of the sealing layer 41 by heating, the sealing layer 41 is softened. The softened sealing layer 41 hermetically seals the edges of the panels 10, 20. At the same time, the adhesives 26a and 74 are softened. As a result, the joint between the low internal pressure container 70 and the back panel 20 and the joint between the pipe 26 and the back panel 20 are hermetically sealed.

The process blocks the gas flow between the interior of the sealing unit 40 and the outer space.

In particular, gas flow is disturbed between the inner and the complex outer container consisting of the sealing unit 40 and in the low inner pressure container 70.

After the sealing layer 41 is softened, the gas flow barrier layer 73 softens almost simultaneously. When this occurs, since the degree of vacuum is maintained in the container 71, the gas flow blocking layer 73 is destroyed by the difference between the pressures on the opposite side, and the gas is released from the inner space of the sealing unit 40 in the container 71. Flows).

This reduces the pressure in the inner space of the sealing unit 40 and puts the panels 10 and 20 from the outside into a state of pressurization.

As shown in FIG. 13C, the pressure reduces the gap between the front panel 10 and the top of the barrier rib 24.

The sealing unit 40 indicates the sealing temperature (30 minutes), at which time it is cooled in the melting furnace 61 and moves.

When the sealing units 40 are cooled at the same or lower point than the softening point of the sealing layer 41, when the panels 10 and 20 are pressed from the outside, that is, the front panel 10 and the barrier ribs ( When the top of 24 is small, the sealing layer 41 is cured.

After the sealing process is completed by the heating device 60, the connector 72 is chipped off by the burner to block the exhaust port 21b.

At this time, one end of the pipe 26 is cut off, and the vacuum pipe is connected to the pipe 26. Gas is exhausted from the inner space of the sealing unit 40 to generate a vacuum in the inner space.

Example of  Sealing Process Effect

In this embodiment, as in the first embodiment, the panels 10 and 20 are adhered to each other while being equally pressed from the outside. That is, it means that both panels 10 and 20 are adhered while the front panel 10 and the upper portion of the barrier rib 24 are completely in contact with each other.

In the first embodiment, the vacuum pump is connected to the sealing unit 40. In the third to fifth embodiments, the internal pressure of the furnace is reduced or increased. This embodiment does not have this condition. With this configuration, it is easy to carry out a continuous sealing process using the continuous heating device as the heating device 60.

In the process of generating the low internal pressure container 70, if the capacity of the container body 71 is determined after the gas flow blocking layer 73 is broken, the pressure of the sealing unit 40 is in the range of 10 to 600torr.

This is because when the pressure of the sealing unit 40 is 10torr or less, the sealing layer 41 is broken by the difference between the pressures on the opposite side, and when the pressure of the sealing unit 40 is 600torr or more, the pressure provides a small amount of effect. Weak as much as we do

Modification of this embodiment

In the present embodiment, the gas flow barrier layer 73 is made of low melting glass and melted by heating during the sealing process. However, the gas flow blocking layer 73 is composed of a material that melts or decomposes by application of all energy such as light or ultrasonic waves. In this case, energy such as light or ultrasound is applied to the gas flow barrier layer 73 during the sealing process.

For example, the gas flow barrier layer 73 consists of a novolak resin, and light shines onto the novolak resin during the sealing process. This process operates in the same way as in the present embodiment, and provides the same effect.

Eighth embodiment

In this embodiment, the sealing process is performed as follows. The sealing unit 40 is heated at a high temperature and sealed so that the gas blocks gas flow between the inner space and the outer space, thereby cooling the sealing unit 40 to reduce the pressure in the inner space, thereby closing the sealing unit 40. Creates a difference between the external pressure and the internal pressure.

Figure 14 shows a belt conveyor type heating apparatus used to seal the sealing unit 40 in this embodiment. 15 shows a sealing unit 40 located in a belt conveyor type heating device in a sealing process.

In the sealing process of this embodiment, one end of the opened linear pipe 26 is connected to the exhaust port 21a of the sealing unit 40 (FIG. 15). The sealing unit 40 is sealed using the belt conveyor type heating device 80 shown in FIG.

The heating device 80 has the same structure as the heating device 60 used in the seventh embodiment except for the burner 81 displaced in the melting furnace 61. Burner 81 is used to heat and heat and seal one end of pipe 26. The position of the burner 81 in the melting furnace 61 is set in an area where the sealing unit 40 delivered by the conveyor belt 62 in the melting furnace 61 reaches the highest temperature (peak temperature).

The sealing unit 40 of the pipe 26 is sealed by the heating device 80 as follows.

The sealing unit 40 is located on the conveyor belt 62 of the heating device 80, and is delivered from the melting furnace 61. The sealing unit 40 is heated at the sealing temperature (500 ° C.), which is higher than the softening point of the sealing layer 41 (380 ° C.) while being delivered from the furnace 61. For example, the temperature increase rate in the overheat is 10 ℃ / min.

If the sealing unit 40 indicates a peak temperature (10 minutes), then one end of the pipe 26 is heated and melted to be sealed by the burner 81. In this step, since the sealing layer 41 and the adhesive 26a are softened as in the fifth embodiment shown in FIG. 9, the gas flow between the inner and outer spaces of the sealing unit 40 is disturbed. In other words, the inner space is hermetically sealed.

 After passing through the burner during delivery in the furnace 61, the periphery 40 is cooled, where it moves in the furnace 61. In a hermetically sealed space, the pressure is proportional to absolute pressure (Boyle Charles' law).

As a result, the pressure in the interior space of the sealing unit 40 is reduced by reducing the temperature there. This causes a difference in pressure between the outside and the inside of the inner space, causing the panels 10 and 20 to be pressed from the outside. Further, when the peripheral portion 40 moved in the melting furnace 61 is cooled at the softening point of the sealing layer 41, the sealing layer 41 and the pressure-sensitive adhesive 26a are cured. This means that the panels 10 and 20 adhere to a small gap between the front panel 10 and the top 24 of the barrier ribs. The pipe 26 is also adhered to the rear panel 20.

The sealing process follows a vacuum evacuation process in which one end of the pipe 26 is blocked and opened, the vacuum pump is connected to one end, and the gas is evacuated from the internal space by the vacuum pump to generate a vacuum.

Example of  Sealing process effect

As in the seventh embodiment, in this embodiment, the panels 10 and 20 are adhered to each other while receiving the same pressure from the outside. This means that the panels 10 and 20 adhere to each other while the front panel 10 and the upper portion of the barrier rib 24 are completely in contact with each other. With this configuration, it is easy to carry out a continuous sealing step using a continuous heating device such as the heating device 80.

Note that a sufficient gap between the external pressure and the internal pressure of the sealing unit 40 is required when the sealing layer 41 is cured to produce a sufficient effect here. Therefore, one end of the pipe is blocked at a temperature (peak temperature) 10 ° C. higher than the softening point of the sealing layer 41, and several 10 ° C. are preferred.

Modification of this embodiment

In this embodiment, one end of the pipe 26 is heated and sealed by the burner 81 to block gas flow between the inside and the outside of the sealing unit 40.

However, the following method also applies.

One end of the pipe 26 is first filled with low melting glass of softening point slightly below the peak temperature. Thereby, the low melting glass softens and seals one end of the pipe before the sealing unit 40 reaches the peak temperature, eliminating the need to heat one end of the pipe with the burner 81.

As the temperature of the sealing unit 40 begins to decrease from the peak temperature, the low melting glass at one end of the pipe hardens. When the temperature of the sealing unit 40 further decreases and reaches the softening point of the sealing layer 41, a difference between the external and internal pressure of the sealing unit 40 occurs. As a result, the effect of this embodiment is also generated by the above modification.

Alternatively, as in the sixth embodiment, the exhaust port 21b is opened in the rear panel 20, and one end of the sealed linear pipe is connected to the exhaust port 21b. Here, nothing is attached to the exhaust port 21a while the exhaust port 21a is opened.

When the sealing unit 40 reaches the peak temperature, the softening point of the low melting glass is somewhat lower than the peak temperature falling to the exhaust port 21a to seal the exhaust port 21a. In this case, the low melting glass is cured soon after the temperature of the sealing unit 40 begins to decelerate from the peak temperature in the above change. When the temperature of the sealing unit 40 further decreases and reaches the softening point of the sealing layer 41, a difference between the internal and external pressure of the sealing unit 41 is generated. As a result, the effect of this embodiment is also generated by the above modification.

9th embodiment

In this embodiment, a container complex consisting of a sealing unit and a container is used. In the sealing process, the container complex is heated to a high temperature, while the gas flow between the inside and the outside of the container complex is interrupted, the sealing unit is cooled, and the sealing is performed at a low internal pressure of the sealing unit.

16A to 16C show the sealing process of the sealing unit 41 in this embodiment.

As shown in FIG. 16A, the sealing unit 40 including the front panel 10 and the rear panel 20 is combined into a sealing layer 41 located between the melting furnace 51 as the first embodiment. The setting of this embodiment differs from the first embodiment in that instead of the pipe 26a, one end of the opened container 90 is attached to the exhaust port 21a of the rear panel 20.

The container 90 includes a container 91 with one end opened; A connector 92 protruding from the container body 91 and connecting the container body 91 and the exhaust port 21a; and an extension 93 from the container body 91 in a direction opposite to the connector 92.

In the initial setting for the sealing process, the container 90 is attached to the exhaust port 21a of the container body 91 exposed outside the melting furnace 51. The adhesive 94 is previously applied between the connector 92 and the rear panel 20 so that the coupling between the container 90 and the rear panel 20 is hermetically sealed. In this embodiment, the same material used for the sealing layer 41 is used as the adhesive 94.

An electronic heater 95 for heating the container body 91 is attached to the container body 91.

After the initial setting is completed, the sealing unit 40 is melted at a temperature (480 ° C.) higher than the softening point of the sealing layer 41 (eg, the temperature increase rate is 10 ° C./min at the heating). 51). At the same time, the container body 91 is heated by the electron heater 95 at the selected temperature (200 ° C.). At this time, one end of the expansion 93 is sealed by a burner.

Here, as shown in Fig. 16A, one end of the expansion 93 is sealed, and the sealing layer 41 and the pressure-sensitive adhesive 94 are softened. As a result, the gas flow between the inside and the outside of the sealing unit 40 and the gas flow between the inside and the outside of the container body 91 are disturbed.

At this time, while the sealing unit 41 is maintained at a temperature higher than the softening point of the sealing layer 41 in the melting furnace 51 as shown in FIG. 16C, the electronic heater 95 cools the container body 91. The power is turned off.

The reduction in the temperature of the container body 91 leads to a decrease in the pressure of the container body 91 and to a decrease in the pressure of the closure unit 40. Therefore, as in the eighth embodiment, a difference between the external and the internal pressure of the sealing unit 40 is generated. This causes the panels 10 and 20 to be pressed from the outside.

At this time, the internal temperature of the melting furnace 51 is reduced. The sealing layer 41 and the pressure-sensitive adhesive 94 are cured when the sealing unit 40 is cooled at the softening point of the sealing layer 41. This means that the panels 10 and 20 adhere to the small gap between the front panel 10 and the upper rib 24. In addition, the container 90 is adhered to the rear panel 20.

The sealing process follows a vacuum evacuation process in which one end of the expansion 93 is blocked and opened, and the vacuum pump is connected to one end so that the gas is evacuated from the internal space of the vacuum pump to generate a vacuum.

Example of  Sealing Process Effect

As in the eighth embodiment of the present embodiment, the panels 10 and 20 are adhered to each other while the front panel 10 and the top of the barrier rib 24 are completely in contact with each other.

In the eighth embodiment, the sealing unit 40 itself is cooled to reduce the pressure, while in this embodiment the pressure of the internal pressure of the sealing unit 40 reduces the temperature of the arranged container 90 In other words, the temperature is controlled separately. As a result, unlike the eighth embodiment, the sealing unit 40 need not be heated much higher than the softening point of the sealing layer 41. In this embodiment, it is sufficient that the sealing unit 40 is heated to the same temperature or higher than the softening point of the sealing layer 41.

10th embodiment

In this embodiment, the continuous heating device is used to heat the container complex described above in the ninth embodiment. In the sealing process, the container complex is heated to a high temperature and in a state where gas flow between the inside and the outside of the container complex is blocked, the sealing unit is cooled to seal the sealing unit in a state where the internal pressure of the sealing unit is low.

17 shows a belt conveyor type heating apparatus used to seal the sealing unit 40 in this embodiment. 18 shows a sealing unit 40 located in a belt conveyor type heating device in a sealing process.

In the sealing process of this embodiment as in the eighth embodiment, the sealing unit 40 of the container 90 attached through the exhaust port 21a by the pressure-sensitive adhesive 94 is heated while being delivered from the heating device 100, The sealing unit 40 is sealed as shown in FIG.

The heating device 100 is the same as the heating device 80 used in the eighth embodiment except that the burner 90 for sealing one end of the expansion 93 of the container 90 is displaced in the furnace 61. It has a structure. The position of the burner 101 in the melting furnace 61 reaches the sealing unit 40 delivered by the conveyor belt 62 in the melting furnace 61 at the same or higher temperature than the sealing temperature (softening point of the sealing layer 41). It is set in the area.

In the heating device 100, the ceiling panel 61a is lowered in height between the burner and the outlet. The ceiling plate 61a has a slot 61b, so that the sealing unit 40 is delivered to the belt so that the connector 92 of the container 90 can pass therethrough. The ceiling plate 61a also has a window 61c so that the container body 91 can pass through the sealing unit 40 because it is delivered to the belt.

The sealing unit 40 of the container 90 is located on the conveyor belt 62 of the heating device 100, and is delivered from the melting furnace 61. The sealing unit 40 is heated to the sealing temperature, and indicates the sealing temperature for a while. At the same time, one end of the expansion 93 is heated to be sealed by the burner 101.

In this step, the sealing unit 40 is in the same state as in the ninth embodiment of FIG. 16B. In other words, one end of the expansion 93 is sealed, and the sealing layer 41 and the pressure-sensitive adhesive 94 are softened. As a result, the gas flow between the inside and the outside of the sealing unit 40 and the flow between the inside and the outside of the container 91 are obstructed.

After passing through the burner 101, the sealing unit 40 moves inside the melting furnace 61, so that it is maintained at the same or higher temperature than the softening point of the sealing layer 41, while the container body 91 Since the container is in the melting furnace 61 (the ceiling 61a), the container body 91 is cooled after passing through the window 61c.

 The decrease in temperature of the container body 91 decreases in the pressure of the container body 91 and decreases in the seal unit 40 pressure as in the state of the ninth embodiment shown in FIG. 16C. This creates a difference between the outside of the sealing unit 40 and the internal pressure, causing the panels 10 and 20 to be pressed from the outside.

The sealing layer 41 and the adhesive 94 are cured when the sealing unit 40 is cooled at the softening point of the sealing layer 41. This means that the panels 10 and 20 adhere to a small gap between the front panel 10 and the barrier ribs 24. In addition, the container 90 is adhered to the rear panel 20. At this time, the sealing unit 40 moves in the melting furnace 61.

As described above, the sealing process follows a vacuum evacuation process in which one end of the expansion 93 is blocked and opened, the vacuum pump is connected to one end, and the gas is evacuated from the internal space by the vacuum pump to generate a vacuum.

It is preferable that the shutter only opens when the window 61c is provided with the shutter and the container body 91 passes through the window 61c while maintaining the temperature in the melting furnace 61.

Modification of the method for reducing the pressure in the interior

In the ninth and tenth embodiments, one end of the expansion 93 is initially opened and the container body 91 is heated to allow gas flow between the interior and exterior of the sealing unit 40 and The internal and external gas flow is interrupted and then sealed by the burner. However, if one end of the expansion 93 is initially sealed, it also heats the container body 91 before the sealing layer 41 softens and cools the container body 91 after the sealing layer 41 softens. Is implemented.

In this way, the pressure in the inner space is also reduced.

In the eighth embodiment up to 10, the sealing unit 40 is cooled, and the container 90 connected to the sealing unit 40 is cooled to reduce the pressure in the inner space of the sealing unit 40. However, this can be realized by reducing the number of gas molecules in the inner space.

For example, the oxygen gas is previously in the form of a capsule in the sealing unit 40, the container 90 is connected to the sealing unit 40. When the sealing layer 41 is softened, the laser beam is illuminated in oxygen gas. At this time, the oxygen gas is changed to ozone, and the number of gas molecules contained in the inner space is reduced. This also reduces the pressure in the interior space of the sealing unit 40.

Alternatively, the gas absorber (getter) and gas are initially sealed at the periphery 40, or when providing a catalyst such as heat or light, the container 90 is connected to the periphery 40 where the gas absorber is activated. When activated, the gas is inhibited by absorption at the surface of the gas absorbent material. This is possible in a configuration that reduces the pressure by the number of gas molecules contained in the interior space of the sealing unit 40 and the arrangement therein so that the gas absorbing material is activated when the sealing layer 41 is softened.

To achieve this, the gas absorbing material is active at a temperature higher than the temperature at which the softening point of the sealing layer 41 can be used. Alternatively, the laser beam shines on the gas absorbent material to activate the material when the sealing layer 41 is softened.

 Eleventh embodiment

This embodiment is essentially the same as in the first embodiment except that the bonding layer 45 is formed on top of the barrier ribs on the rear panel 20 before the sealing unit 40 is formed. The bonding layer 45 bonds the barrier ribs 24 with the front panel 10.

The material for the bonding layer 45 will not affect the operation of the PDP and is required to have the ability to bond the barrier ribs 24 and the front panel 10. In this embodiment, the low melting glass used for the sealing layer is used.

The bonding layer 45 is formed by applying a paste containing a bonding material (low melting point glass) on top of the barrier ribs 24 by screen printing, and then firing the applied paste.

Initially, the bonding layer 45 is formed as described above. A pressure difference is generated between the external pressure and the interior of the sealing unit 40 so that the internal pressure is lower than the external pressure as in the first embodiment. This allows the front panel 10 and the rear panel 20 to maintain a uniform pressure from the outside. In this step, the front panel 10 and the top of the barrier ribs 24 are brought into full contact. When the sealing layer 42 and the bonding layer 45 are cured in this state, the upper portion of the front panel 10 and the barrier ribs 24 are tightly bonded.

The PDP manufactured by the method of the present embodiment, in which the upper portion of the front panel 10 and the barrier ribs 24 are completely bonded, has the effect of limiting vibration in the activation of the PDP and improving the display characteristics of the PDP than those of the first embodiment. Even better.

In this embodiment, the technique of forming the bonding layer 45 in advance on the barrier ribs 24 is explained based on the first embodiment. However, the above technique is also provided in the second to tenth embodiments. When the bonding layer 45 is formed on top of the barrier ribs 24 in the second to tenth embodiments, the PDP manufactured in such a manner is that the front panel 10 and the top of the barrier ribs 24 are completely formed. The effect of limiting vibration in the activation of the PDP and improving the display characteristics of the PDP is even better than those of the second to tenth embodiments due to the possibility of internal space to be bonded and filled with discharge gas at high pressure.

Twelfth embodiment

In this embodiment, before the sealing process, the deformation preventing ribs 46 are formed in the sealing layer 41 to be formed at both or one edges of the front panel 10 and the rear panel 20 as shown in Figs. 20A and 20B. It is essentially the same as in the first embodiment except that it is formed near the region.

In the example shown in FIG. 20A, the strain relief ribs 46 are formed along the outside of the sealing layer 41. In the example shown in Fig. 20B, the deformation preventing ribs 46a and 46b are formed along the outside and the inside of the sealing layer 41, respectively.

With this arrangement, the front panel 10 and the rear panel 20 are protected from being deformed even if they are pressurized at their edges by the clip 42. If such a strain relief rib is not formed close to the sealing layer 41, the pressure exerted by the clip 42, such as when the sealing layer 41 is softened during the sealing process, causes the front panel 10 and the back panel 20 to be reduced. Acts on the phase. As shown in Fig. 20D, at the edge of the sealing unit 40, the front panel 10 and the rear panel 20 are close to each other (in the direction indicated by the arrow A in the drawing) and are easily deformed. When this occurs, the front panel 10 and the rear panel 20 are easily deformed from the center apart from each other (in the direction indicated by the arrow B in the figure) by the movement of the lever. Such movement is undesirable as they widen the gap between the front panel and the top of the barrier ribs 24.

On the contrary, if the deformation preventing ribs 46 are formed as described above, deformation of the front panel 10 and the rear panel 20 due to the pressure of the clip 42 may occur even though the sealing layer 41 is closed during the sealing process. It does not occur even if it is softened.

Thus, it is possible to increase the effect of narrowing the gap between the front panel 10 and the top of the barrier ribs 24.

Optionally, deformation of the front panel 10 and the back panel 20 by the pressure of the clips 42 can be prevented by aligning the clips 42 so that the pressing point of each clip is located inside the edges of the panels and More specifically, the clips 42 press the image display area as shown in FIG. 20C. As in the example shown in Fig. 20B, the strain relief ribs are formed not only outside but also inside the sealing layer 41, and the softened sealing layer 41 flows into the display area when the external pressure becomes higher than the internal pressure. It has the effect of preventing that. In other words, the deformation preventing rib 46b serves as the sealing material inflow preventing rib 44 described in the third embodiment.

The strain relief ribs 46 preferably have the same height as the barrier ribs 24 when the front panel 10 and the rear panel 20 are disposed together to be in contact with each other.

This is because when the strain relief rib 46 is higher than the barrier rib 24, gas is generated between the front panel 10 and the top of the barrier rib 24, and the strain relief rib 46 is formed by the barrier rib 24. If lower than), the effect of preventing the deformation of the front panel 10 and the rear panel 20 can not be expected.

An easy way to form the deformation preventing ribs 46 is to use the same material as the barrier ribs 24 on the rear glass substrate 21 of the rear panel 20, as the sealing material inflow preventing ribs 44 are formed. To form.

21A to 21F are partial front views illustrating the shape of the deformation preventing ribs 46 formed on the rear panel 20. In the figure, the diagonally shaded area C represents the area where the sealing layer 41 is to be formed.

In Fig. 21A, the strain relief ribs 46a and 46b are formed like linear lines along the outside and inside of the diagonally shaded area C.

In FIG. 21B, a plurality of anti-deformation ribs 46 are formed at regular intervals crossing over the diagonally shaded area C. In FIG.

In FIG. 21C, a plurality of anti-deformation ribs 46 are randomly formed in the diagonally shaded area C. In FIG.

In FIG. 21D, a plurality of short strain relief ribs 46a are formed diagonally at regular intervals in the diagonally shaded area C, and the strain relief ribs 46b are formed like linear lines along the inside of the region C. In FIG.

In Fig. 21E, the strain relief rib 46a is formed like a short dashed line along the outside of the diagonally shaded area C, and the strain relief rib 46b is a linear line along the inside of the area C in parallel. It is formed as follows.

In FIG. 21F, a plurality of anti-deformation ribs 46a are formed at regular intervals crossing diagonally over the shaded area C, and the anti-deformation ribs 46b are formed like linear lines along the inside of the area C in parallel.

Modification of this embodiment

The technique disclosed in the above embodiment, such as the technique of forming the strain relief rib 46 or the pressing of the image display area by the clips 42, can be applied for the general sealing process of manufacturing PDP, and the internal pressure In order to make it lower than this external pressure, it is not limited to the sealing process in which the pressure difference generate | occur | produces between an external pressure and the inside of the sealing unit 40. FIG.

Thirteenth embodiment

In this embodiment, energy is intensively radiated onto the top of the barrier rib to adhere the top of the barrier rib to the front panel after the sealing process is performed in the manner described in any of the first to tenth embodiments.

22A to 22C illustrate a process of attaching an upper portion of the barrier rib to the front panel by emitting a laser beam.

Firstly, the front panel 10 and the rear panel 20 are arranged together to form a sealing unit 40, the panels soften and stick together and then among them described in the first to tenth embodiments. One method is used to cure the sealing layer 41 (FIG. 22A).

Secondly, as shown in Fig. 22B, the laser beam is emitted from the laser processing apparatus 200 on the top of the barrier rib through the front panel 10 of the formed sealing unit 40.

As will be described in detail later, the laser processing apparatus 200 includes a plurality of components operative to emit a laser beam as follows. The YAG laser oscillator 201 emits pulses of the laser beam to the laser head 203, while the laser head 203 is vertical and horizontal (in the X and Y axis directions shown in Fig. 22B) to the work table (sealed). Inject unit 40). A converging lens 204 disposed on the laser head 203 focuses the laser beam on the surface of the work surface, such as an elliptical spot.

When the laser beam is emitted over the top of the barrier rib, the top is heated intensively at a higher temperature than the softening point of the barrier rib material (ie 500-600 ° C.). When so occurring, the material softens (dissolves) and then cures. This allows the top of the front panel and barrier ribs to stick together after they have been in contact for this time.

Therefore, the upper portion of the front panel and the barrier ribs is scanned in the direction as indicated by the arrow in Fig. 22B (the diagonally shaded areas indicate the adhered areas), and the barrier ribs along the longitudinal direction of the sealing unit 40 are scanned. The spots of the laser beam emitted over the top of the are adhered together completely.

Fig. 22C shows a sequence of dot adhesive regions (diagonally shaded regions in the drawing) formed by intermittently emitting a laser beam. However, the adhered area may be formed like a straight line by emitting the laser beam with very short dashes or continuously.

The upper portion of the front panel and the barrier ribs may be adhered together by radiating a laser beam as described above, although there is no pressure difference between the external pressure and the interior of the sealing unit 40. However, it is preferable to carry out such a process in which the pressure in the inner space of the sealing unit 40 is kept lower than the external pressure as described in the sealing process of Examples 1-5 and 7-10. Do. This is because the top of the front panel and the barrier ribs stick together while they are in contact.

23 is a perspective view of a special laser processing apparatus 200.

The laser processing apparatus 200 shown in FIG. 23 is classified into a gantry-type. In this laser processing apparatus 200, the table 202 is held to be movable in the X-axis direction as shown in FIG. The arch 210 is formed over the table 202. The laser torch 211 is held on the arch 210 to be able to move in the Y axis direction. The laser torch 211 and the table 202 are accurately driven by a stepping motor (not shown).

The sealing unit 40 is fixed on the table 202 by a vacuum chuck mechanism.

The laser head 203 is fixed on the laser torch 211. The laser beam emitted from the laser oscillator 201 is guided to the laser head 203 through an optical fiber cable 212 made of quartz glass. Rather, the laser oscillator 201 is achieved by a YAG laser oscillator or CO ₂ laser oscillator capable of emitting a powerful beam in a short time. For example, the output of the laser oscillator 201 is 10 Hz.

Initially, the sealing unit 40 stacked on the table 202 for each barrier rib extends along the X-axis direction shown in FIG. The first barrier ribs adhere to the front panel by moving the spot of the laser beam radiated onto the top of the barrier ribs in the X-axis direction. The spot is moved by the pitch of the barrier ribs in the Y-axis direction. This process is repeated for the remainder of the barrier rib until the top of the barrier rib is fully adhered.

Effect of this embodiment

In a preferred embodiment, the top of the front panel and the barrier ribs are securely adhered. As a result, the effect of preventing vibration and the effect of improving PDP quality in PDP activation are excellent as in the eleventh embodiment.

Experimental results by PDP driving produced by the method of this embodiment indicate that the resonance of the barrier ribs and the front panel occurs while in the conventional product, but not. This result also shows that the melt noise level of the PDP of this embodiment is the same as that of the eleventh ordinary product, and there is no cross talk between cells.

Unlike the eleventh embodiment, the front panel and the upper portion of the barrier rib are adhered to the upper portion of the barrier rib without applying an adhesive, thereby simplifying the manufacturing process.

According to the method of the present embodiment, the front panel and the upper portion of the barrier ribs have the advantage of being adhered to the material of the upper portion of the barrier ribs, not the adhesive. When the image display area of the PDP contains an adhesive, the adhesive can release impurities to the discharge gas. However, this is not possible in the PDP manufactured by the method of this embodiment.

However, the bonding layer 45 is formed in advance on the barrier ribs 24 as in the eleventh embodiment, and after the sealing device 40 is formed, on the front panel and the barrier ribs as in this embodiment. The laser beam may be irradiated onto the bonding layer 45 to adhere. This method ensures no sticking through this advantage.

When a material such as a black filler that improves absorption of the laser beam is mixed with the material of the bonding layer 45, adhesion is made more firm.

Modification of this embodiment

In general, the laser processing apparatus 200 of the above-described embodiment may be performed by precise two-dimensional laser processing for the work by the micro size. Adhesion can be done more precisely by placing an apparatus that observes the working surface described below.

24 shows a laser processing apparatus 200 having an observation head 205 and a laser head 203. Observation head 205 includes a probe beam emitter 206 that irradiates the probe beam on the working surface and a detector 207 that detects the probe beam reflected from the working surface. The observation head 205 scans the work table (sealing unit 40) vertically and horizontally (directions X and Y in Fig. 22B) as the laser head 203 does.

The controller 208 receives the signal from the observation head 205 and scans the detector 206 (ie, the controller 206 stores the X-Y coordinate values on the table 202 as in the information display position of the barrier ribs). The shape of the barrier ribs 24 is monitored.

The controller 208 also uses the position information stored on the barrier ribs to Y to direct the laser beam to the center of each barrier rib when the laser head 203 scans the barrier ribs in the X direction. Fine-tune in the direction.

This configuration ensures that the barrier ribs 24 are irradiated to the middle of each barrier rib even if the barrier ribs 24 are curved (snake) or partially flawed, so that the precision of the front and rear barrier ribs is large.

Optionally, the intensity of the laser beam can be adjusted by monitoring the width of the barrier ribs or the reflectance of the laser beam using the laser processing apparatus 200 shown in FIG. 24.

When the top of the barrier rib is softened by the irradiation of the laser beam, as the width of the barrier rib increases or the reflectance increases, the temperature caused by the laser irradiation decreases and the adhesion area decreases. In other words, when the bonding layer is formed on top of the barrier ribs, the size of the bonding material also increases, so that the adhesion area can be increased when the width of the barrier rib increases. Thus, when the radiation intensity of the laser beam is fixed, the adhesive state (region of barrier ribs that dissolves) changes each position on top of the barrier ribs as the width or reflectivity of the ribs changes.

The above problem can be solved by controlling the radiation intensity or the radiation angle of the laser beam in accordance with the monitored width and the monitored reflection width at each position above the barrier rib.

In this embodiment, after the sealing process in which the pressure inside the sealing unit 40 is lower than the external pressure, an adhesive process is performed in which the front panel 10 and the upper portion of the barrier ribs 24 are adhered by irradiation of a laser beam. However, the adhesion process can be carried out after the usual sealing process. In this case, the adhesion is lower than that of the present embodiment because the adhesion is adhered while the gap between the front panel 10 and the top of the barrier ribs 24 increases.

In the present embodiment, after the sealing process, an adhesive process is performed in which the upper portion of the front panel 10 and the barrier ribs 24 are adhered by irradiation of a laser beam. However, the adhesion process can be carried out before or in parallel with the usual sealing process.

When the adhesion process is performed before the sealing process, the edge of the sealing unit 40 is secured to the panel by the outer sealing layer as in the second embodiment and from the inner surface of the sealing unit 40 to reduce the internal pressure. It is desirable for the panel to stick while the gas is exhausted.

In this embodiment, the top or the adhesive of the barrier rib is softened (melted) by irradiation of a laser beam. However, the top of the barrier ribs or the pressure-sensitive adhesive may be softened by irradiating energy such as ultraviolet rays on the top of the barrier ribs or by heating the front panel 10 greatly by a heater.

Optionally, the sealing unit 40 includes a front panel and a rear panel while the front panel is heated and the top or adhesive of the barrier rib contacting the front panel 10 near the softening point of the barrier rib 24 is softened to the front panel and the barrier rib. It can be formed by placing the panel.

My 14 Example

In the present embodiment, an exhaust pipe sealing device that can easily chip off the exhaust pipe (for example, the pipe 26 of the first embodiment) will be described.

25 is a perspective view showing an exhaust pipe sealing device 310 attached to the exhaust pipe 300. 26 is a cross-sectional view of the exhaust pipe sealing device 310 attached to the exhaust pipe 300.

Although the sealing device is not shown in FIGS. 25 and 26, the base of the exhaust pipe 300, which is the lower part of the drawing, is connected to the air hole in the rear panel (see FIG. 5).

The exhaust pipe sealing device 310 includes a heating unit 311 for heating the exhaust pipe 310, and a limiting member 315 for restricting the position of the heating unit 311 in relation to the exhaust pipe 300.

The heating unit 311 includes a cylindrical support member 312 having a diameter larger than the outer diameter of the exhaust pipe 310 and an electric heater 313 in which a coil is wound completely inside the support member 312.

The restricting member 315 becomes a cylindrical member at the center where a hole for inserting the exhaust pipe 300 is formed around the central axis. The end of the limiting member (lower end in the drawing) is formed of a fixing member 316 having a diameter smaller than the diameter of the limiting member 315 so that the fastening member 316 is connected to the end of the heating unit 316 (upper part of the drawing). It is fixed.

The limiting member 315 is formed to be divided into two parts (referred to as limiting member parts 315a and 315b) by a plane passing through the central axis.

The preferred material 315 of the restricting member 315 is a ceramic having a higher insulator and softening point than the exhaust pipe 33.

The hole of the restricting member 315 preferably has a diameter larger than the outer diameter of the exhaust pipe 310. This is because if the diameter of the member 316 is larger than the outer diameter of the tube 300, the member 315 vibrates incapable of positional restriction.

In addition, the outer diameter of the fixing member 316 is preferably smaller than the inner diameter of the heating unit 311. This is because the heating unit 311 vibrates so that the electric unit 311 is in contact with the electric heater 313 when the former is larger than the latter, and the heating heater 313 cannot perform positional limitation when the former is smaller than the latter. .

The configured exhaust pipe sealing device 310 seals the exhaust pipe 300 as follows.

First, the heating unit 311 is located at a position where the exhaust pipe 300 is chipped off. Thereafter, the fixing member 316 of the limiting member 315 is fixed to the heating unit 311. Finally, the current passes through the electric heater 313 to heat and chip off the exhaust pipe 300.

Example of  effect

In this embodiment, the limiting member 315 is formed to be divided into the limiting member portions 315a and 315b. However, the limiting member 315 need not be formed to be divided into parts.

The exhaust pipe sealing device 310 shown in FIG. 26 is configured such that an end of the heating unit 311 can be fixed to the outside of the fixing member 315 of the limiting member 315. However, the exhaust pipe sealing device 310 may be configured such that the end of the heating unit 311 can be fixed inside the fixing member 315 of the limiting member 315 as shown in FIG. 26.

The exhaust pipe sealing device 310 shown in FIG. 26 is configured such that an end of the heating unit 311 is fixed to the outside of the fixing member 315 of the limiting member 315. However, the exhaust pipe sealing device 310 may be configured such that both ends of the heating unit 311 can be fixed to the limiting member 315 as shown in FIG. 28. That is, the limiting member 315 limits the position of the heating unit 311 to two parts. This allows the limiting member 315 to more firmly remove the position of the electric heater 313 and the exhaust pipe 300 and prevents contact with each other.

The exhaust pipe sealing device 310 shown in FIG. 26 is configured to form a unit in which the heating unit 311 and the restricting member 315 are separated. However, the heating unit 311 and the limiting member 315 may be formed as one unit of the exhaust pipe sealing device 320 as shown in FIG. 29.

The exhaust pipe sealing device 320 shown in FIG. 29 is formed such that the electric heater is wound inside the cylindrical limiting unit 321 on the end where the lid 321a is formed. A hole for inserting the exhaust pipe 300 is formed in the center of the lead 321a.

30 may be formed as a unit such that the electric heater is wound inside the cylindrical limiting unit 321 on both ends where the leads 321a and 321b are formed.

 The exhaust pipe sealing device 310 may be divided into two parts by a plane passing through the central axis. 30 shows one of the divided parts.

Exhaust duct 300 may be chipped off by securing device 320 or 330 to exhaust duct 300 and passing current through an electric heater, such as exhaust duct sealer 310, by means of exhaust duct sealer 320 or 330. Can be.

Modifications of the first to fourteenth embodiments

In the PDP of the above embodiment, the barrier ribs 24 are formed on the rear substrate 20. However, barrier ribs may be formed on the front substrate. In the PDP of the above embodiment, the present invention is applied to an AC type PDP. However, the present invention is generally applicable to the manufacture of gas discharge panels as long as they can be formed by adhering the panel to another panel on which barrier ribs are formed.

Gas discharge panels, in particular PDPs, made with the method and apparatus of the present invention can be used as displays in computers or TVs and are particularly suitable for large screen displays.

Claims (7)

A gas discharge panel manufacturing method comprising a sealing step of melting and sealing an exhaust pipe attached to a sealing unit configured by a pair of panels facing each other, A first step of disposing a heating element at a position away from the exhaust pipe by a predetermined distance; A gas discharge panel manufacturing method comprising a second step of causing the heating element to heat the exhaust pipe. The method of claim 1, In the first step, the heating element is a gas discharge panel manufacturing method, characterized in that arranged in a position away from the exhaust pipe by a predetermined member. An exhaust pipe sealing device for melting and sealing an exhaust pipe attached to a sealing unit configured by a pair of panels facing each other, And a heating element holding means attached to the exhaust pipe and holding the heating element at a predetermined distance away from the exhaust pipe. An exhaust pipe sealing device for melting and sealing an exhaust pipe attached to a sealing unit configured by a pair of panels facing each other, A cylindrical body having a heating element maintained therein, the cylindrical body having a heating unit having an inner diameter larger than the outer diameter of the exhaust pipe; And a restricting member for limiting the position of the heating unit such that the heating unit is disposed around the exhaust pipe at a predetermined distance away from the exhaust pipe. The method of claim 4, wherein The restrictive member may be divided into two parts by a plane passing through a central axis of the exhaust pipe. The method according to claim 4 or 5, And the restricting member is disposed at two or more places along the exhaust pipe between the heating unit and the exhaust pipe. The method of claim 4, wherein The heating unit further comprises an insulator, And said heating element is wound in an insulator in a coil shape.

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