JPH07262924A - Frit glass molding method and image display using the frit glass molding method - Google Patents

Abstract

PURPOSE:To improve the workability in sealing process and prevent thermal damage to electron emitting part and electrode parts by heating a slurry in which frit glass powder, solid-phase carbon dioxide powder, and an organic substance which is in liquid state at the solidifying temperature of carbon dioxide are mixed is heated to the melting point of the glass powder and molded. CONSTITUTION:Low melting point glass frit powder 101 and dry ice powder 102 are stirred in a heat insulating container 103. An organic solvent 104 is added to the mixture and the resulting mixture is stirred. In that case, any type of organic solvent may be used as long is it is in liquid-phase at the solidifying point of dry ice. Consequently, the glass frit powder 101 becomes a slurry 105 at a low temperature. The following process may differ depending on whether the slurry 105 is used for coating or the slurry 105 is used as a sintered body. In the former case, the slurry 105 is applied to a back plate 10 by a squeezing apparatus 106 or applied to a frame 108 to give a sealed product 109. On the other hand, in the latter case the slurry 105 is poured into dies 110, and after molded, the glass molded body is taken out and presintered to produce a glass sintered body 111. The sintered body 111 is sandwiched between a back plate 107 and a frame 108 and heated to give a sealed product 109.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding frit glass mainly for sealing glass containers, which is required to have airtightness and insulating properties, and an image display device using the method. The present invention relates to the above method in the manufacturing process of a flat image display device that needs to be held in vacuum.

[0002]

2. Description of the Related Art Conventionally, flat panel image display devices include plasma displays, EL display devices, and flat panel image display devices using electron beams, and the demand for larger screens and higher definition is increasing. There is an increasing need for self-luminous flat panel image display devices.

In a flat panel image display device using an electron beam,
For example, in a vacuum panel sandwiched between a face plate and a back plate, a surface conduction electron-emitting device is used as an electron source for generating an electron beam, and the electron beam is accelerated to irradiate a phosphor to cause an image to be emitted. A thin image display device for displaying is disclosed in JP-A-3-261024.

FIG. 2 is a sectional view showing an example of a flat image display device using the surface conduction electron-emitting device as described above.

In FIG. 2, 207 is a back plate which is made of an insulating material such as soda lime glass and is used as a substrate,
Reference numeral 214 is a surface conduction electron-emitting device portion. In the same electron-emitting device, 212 is a device electrode installed at a constant interval (about 2 μm), and 213 is an organic Pd (ccp).
4230: Okuno Seiyaku Co., Ltd.) is an element thin film formed by coating, and the electron-emitting device portion 214 is an element thin film 213.
Partially formed. The electron-emitting device section 214 is
It is formed by applying a voltage between the element electrodes 212 and conducting electric heating to emit electrons.

Besides, a thin film of a surface conduction electron-emitting device using a SnO ₂ film and a thin film of Au [G. Dit
tmer: "Thin solid films", 9, 317 (1972)], In _20
3 / SnO ₂ thin film [M.Hartwell and CG Fons
tad: "IEEE Trans ED conf.". 519 (1975)], by carbon thin film [Haraki Araki et al .: Vacuum, Vol. 26, No. 1,
22 (1983)] and the like are reported.

Further, in FIG. 2, 215 is an insulating layer formed on the back plate 207, and 216 is a substrate 20.
7 and the insulating layer 215, a grid 217 which is a modulation electrode having holes through which an electron beam passes.
Is a panel-shaped soda-lime glass, a face plate provided with a phosphor 218 covered with a metal back 219, which is an Al thin film, and 220 is a frit glass after sealing. Reference numeral 208 is an outer frame.

To form the image display device, a frit glass is sandwiched between the outer frame 208, the face plate 217 and the back plate 207, placed in an electric furnace and heated to a temperature higher than the melting point of the frit glass for sealing. Done by

The frit glass used in the above-mentioned formation is a powder before sealing, and it is difficult to use the powder alone as a work. Therefore, it is generally applied after adding a binder and a solvent to form a slurry. , Sealing is done.

The above binder is used for the purpose of imparting plasticity to the frit glass powder for improving workability. Acrylic resins, fluororesins and polyvinyl butyral are disclosed in JP-A-4-321258 as binders, and water, alcohols, methyl ethyl ketone, toluene, xylene and the like are disclosed as solvents.
A dispersant and an antifoaming agent are used depending on the combination of the binder and the solvent.

As a means for omitting the frit glass coating step, there is a method of using a frit glass sintered body. A frit glass powder made into a slurry by adding a binder and a solvent is subjected to squeeze molding using a dispenser or the like, or press molding using a metal mold or the like to obtain a molded body.
This molded body is subjected to a process called calcination, which is performed at a temperature lower than the sealing temperature of the frit glass (generally about 30 ° C. lower than the sealing temperature). Pre-baking is a process in which frit glass powders are sintered and molded, and at the same time as sintering, the binder is decomposed and evaporated, and heating is performed to obtain a frit glass sintered body with less bubbles and residues. Is performed at a temperature lower than the melting temperature.

The frit sintered body formed as described above is sandwiched between the face plate 217, the outer frame 208 and the sealing portion of the back plate 207 and heated to seal.

[0013]

However, the above-described conventional frit glass molding method has the following problems.

In the case of a low-melting point frit glass having a sealing temperature of 400 ° C. or lower, the sintering temperature of the frit glass is generally lower than the decomposition temperature and the evaporation temperature of the binder, so that the binder is completely decomposed and evaporated. It is difficult to get it done.

A face plate of a flat image display device,
When the frame and the back plate are sealed, it is desirable that the sealing temperature of the frit glass is lower in order to reduce the damage due to heat at the time of sealing the electron source portion and the electrode portion. In particular, in order to obtain the above-mentioned frit glass sintered body, since the calcination temperature is lower than the sealing temperature, it is not possible to decompose and evaporate the binder having a higher decomposition temperature than the sealing temperature. It will be more difficult.

If the decomposition and evaporation of the binder are not complete, problems will occur in maintaining the airtightness and insulating property and the strength of the frit glass. Therefore, the flat image display device is sealed by using a low-melting-point frit glass powder which is not slurried, or a frit glass powder which is slurried and has a sealing temperature of 400 ° C. or higher is used. However, the former method is
In addition to poor workability, the low-melting frit glass powder may be scattered during molding, which is a problem for the health management of workers. The latter method has a problem that heat damage to the electron emitting portion and the electrode portion at the time of sealing is larger than that in the case of using the low melting point frit glass.

The present invention has been made in view of the problems of the above-described conventional technique, and when applied to the manufacture of an image display device, the workability of the sealing process can be improved. It is an object of the present invention to realize a frit glass molding method which does not give heat damage to the electron emission portion and the electrode portion.

[0018]

The frit glass molding method of the present invention comprises mixing a frit glass powder, a powdery solid-phase carbon dioxide powder, and an organic substance which is in a liquid phase at the freezing point of carbon dioxide and stirred to form a slurry. And the first step
And a second step of heating the slurry obtained by the above step to a temperature at which the frit glass powder is melted or above and molding the slurry.

In this case, between the first step and the second step, a third step of heating the slurry of the first step to a temperature below the temperature at which the frit glass powder melts and molding the slurry may be carried out.

The image display device of the present invention is an image display device in which a face plate having a phosphor and a back plate having an electron source for generating an electron beam are opposed to each other by frit glass and sealed. The face plate and the back plate are sealed by the frit glass molding method described above.

[0021]

The inventors of the present invention have conducted research to solve the above-mentioned problems in the method for forming a low melting point frit glass, and as a result, have found that powdery solid phase carbon dioxide (vaporization temperature -78.5 ° C,
The solution was achieved by utilizing the fact that a liquid phase organic substance is mixed and agitated to form a slurry in the temperature range of existence of dry ice.

In the low melting point frit glass molding method provided by the present invention, dry ice as a binder for molding and an organic substance in a liquid phase in the temperature range of existence of dry ice are mixed with frit glass powder and stirred. To form a slurry, which is then heated to a temperature at which the frit glass powder melts or above to be molded.

Since the temperature at which the frit glass powder melts is the temperature at which both the dry ice and the organic substance present in the slurry evaporate, the temperature at the time of heat molding may be higher than the temperature at which the frit glass powder melts. It is possible to lower the temperature at that time than before. In addition, this makes it possible to seal with frit glass that has been made into a slurry, which was difficult in the past when manufacturing an image display device.

When a step of heating the slurry below the temperature at which the frit glass powder melts and molding is added, dry ice and organic substances evaporate at this stage of calcination, so that the coating step is omitted and the final step is completed. It is possible to further improve the properties of the frit glass that is molded as desired.

In the image display device of the present invention manufactured by using the above-described frit glass molding method of the present invention, the temperature at the time of heat molding can be made lower than before, so that the electron emission part and the electrode part of the image display device can be obtained. The heat damage of the frit glass is reduced and the frit glass powder can be sealed without scattering.

[0026]

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

FIG. 1 is a diagram for explaining a process of sealing a back plate and a frame of an image display device according to the manufacturing method of the present invention.

In this embodiment, first, the low melting point frit glass powder 101 and the dry ice powder 102 are stirred in the heat insulation container 103 (step 1). Then, the organic solvent 104 is further added and stirred (step 2). The organic solvent at this time is not particularly limited in kind as long as it is in a liquid phase at the temperature of the presence of dry ice, but a desirable substance is one which evaporates and decomposes at a temperature below the calcination temperature of the low melting point frit glass. Specific examples thereof include acetone and ethyl acetate described later.

In the above stirring operation, the mixture of the organic solvent 104 and the dry ice powder 102 becomes the dry ice powder 1
02 is diffused in the solvent to become a low temperature viscous substance, and as a result, the low melting point frit glass powder 101 becomes a low temperature slurry 105 (step 3). By using dry ice powder in this way, a binderless process can be realized.

After this, the process performed is the slurry 105.
Is used for coating or the slurry 105 is used as a sintered body.

When the slurry 105 is applied and used for sealing, the low temperature slurry 105 obtained in the step 3 is applied to the back plate 10 by a squeezer 106 or other means.
7 (step 4) or the frame 108 (step 5), and the slurry 108 is sandwiched between the frame 108 and the back plate 107 to be integrated. After that, the back plate 107, the frame 108, and the sealed portion thereof are naturally left for a predetermined time so as not to be cracked due to a difference in coefficient of thermal expansion due to rapid heating, and then heat sealed to obtain a sealed product 106 (step 6). .

Carbon dioxide and the organic solvent 104 contained in the low temperature slurry 105 evaporate during heating, so that no bubbles or residues remain in the low melting point frit glass after sealing.

When the slurry 105 is used as a sintered body, the low temperature slurry 105 in step 3 is poured into a mold 110 for producing a sintered body, and the mold 110 is molded by applying an appropriate pressure. After this, mold 110 or mold 1
The low melting point frit glass molded body produced as a result of the pressure treatment in Steps 10 to 7 is taken out, and the low melting point frit is subjected to temporary sintering by heating at a temperature lower than the sealing temperature to evaporate carbon dioxide and the organic solvent 104. A glass sintered body 111 is produced (step 7). Then, the low-melting-point frit glass sintered body 111 produced in step 7 is attached to the back plate 107 and the frame 1.
It is sandwiched between 08 (step 8), heated and sealed to obtain a sealed product 109 (step 9). As described above, when sealing is performed after the slurry is made into a sintered body, the dry ice and the organic solvent are evaporated during the pre-sintering in step 7, so that the degassing is sufficiently performed, and after the sealing, The low melting point frit glass can be made in a good state.

As described above, the face plate, the outer frame and the back plate of the image display device are sealed and the image display device is manufactured.

Although the embodiments of the present invention have been described above, the present invention is not limited to image display devices, and has a low melting point in sealing parts such as IC packages where airtightness and insulation are required. Effective for using frit glass.

The present invention will be described in more detail with reference to specific examples.

Example 1 The face plate, frame and back plate of the image display device were sealed according to the present invention described above. Specific examples will be described below according to the steps shown in FIG.

As the low melting point frit glass powder used for sealing, one having a sealing temperature of 350 ° C. and a powder average particle size of 4.9 μm was used.

Frit glass powder: 10 g and dry ice powder 3 g are stirred in a heat-retaining container for keeping a low temperature. The frit glass powder was dried as much as possible in advance and cooled to -80 ° C or lower using liquid nitrogen to prevent vaporization of dry ice as much as possible. To this mixed powder of frit glass powder and dry ice, 2 g of acetone cooled to the vaporization temperature of dry ice was mixed. Acetone has a melting point of -94 ° C and a boiling point of 5
It was 6 ° C. and was selected as an organic material suitable for the conditions of the present invention. Since dry ice powder diffuses in acetone,
The frit glass powder, which was previously stirred with the dry ice powder, was uniformly dispersed in acetone. When dry ice is mixed in acetone, it becomes a low temperature viscous substance, and therefore the mixture of frit glass powder, acetone and dry ice powder becomes a low temperature slurry. This low-temperature slurry is applied to a face plate and a frame that have been cooled to about the same temperature, placed in a sealing furnace with the sealing surfaces aligned, and left for 2 hours, then heated at a temperature increase rate of 5 ° C / minute. Sealing was performed at 350 ° C. for 10 minutes.

The frit glass after sealing had a glossy surface and no bubbles or residues were observed. Further, neither bubbles nor residue was observed between the glass surface and the surface.

As described above, good sealing could be performed at the sealing temperature of 350 ° C.

[Embodiment 2] As Embodiment 2, a method of manufacturing an image display device manufactured by using a low melting point frit glass sintered body will be described.

Under the conditions of Example 1, frit glass powder,
Acetone and dry ice powder were mixed to make a slurry, and then the cooled syringe was filled with the slurry and squeezed out (not shown). The diameter of the injection part of the syringe is 3 mm. The squeezed slurry was left for 2 hours, then heated at a temperature increase rate of 5 ° C./minute, and baked at 320 ° C. for 10 minutes.

No cracks, bubbles or residues were observed in the low melting point frit glass after sintering. The face plate and the frame were sealed using this low melting point frit sintered body. The sealing conditions are temperature rising rate of 5 ° C / min, 350 ° C, 10
Minutes.

The frit glass after sealing had no gloss or bubbles on the glossy surface. No bubbles or residues were observed between the glass surface and the surface.

As described above, a good low melting point frit glass sintered body was obtained at the calcination temperature of 320 ° C., and good sealing could be performed at a sealing temperature of 350 ° C. using the sintered body.

[Example 3] As Example 3, a case where a low melting point frit glass is molded by using ethyl acetate as another kind of organic solvent will be described. Ethyl acetate has a melting point of -83.6 ° C and a boiling point of 77 ° C, and is an organic substance that satisfies the conditions of the present invention.

Frit glass powder: 10 g, ethyl acetate 2 g, and dry ice powder 3 g were mixed and stirred in the same manner as in Example 2, and then the face plate and the frame were sealed.
After standing for 2 hours, heat at a temperature rise rate of 5 ° C / min to 350
As a result of sealing at 10 ° C. for 10 minutes, no bubbles or residues were observed on the frit glass on the glossy surface, and no bubbles or residues were observed between the frit glass and the glass surface.

Even when the organic solvent was changed to ethyl acetate as described above, good sealing could be performed at the sealing temperature of 350 ° C.

[Embodiment 4] As Embodiment 4, a case of producing a low-melting point frit glass sintered body using ethyl acetate will be described.

Frit glass powder, ethyl acetate and dry ice powder were mixed under the conditions of Example 3 to form a slurry, and then a sheet-shaped frit was produced using a cooled mold. The weight of the mold was 1800 g, and pressure molding was performed using only the weight of this mold. The produced sheet frit has a length of 120 mm, a width of 3 mm, and a heat of 0.5 mm. After leaving this sheet frit for 2 hours, the temperature rise rate is 5 ° C /
It was heated for 10 minutes and baked at 320 ° C. for 10 minutes. No cracks, bubbles, or residues were observed in the low melting point frit sintered body after firing.

The face plate and the frame were sealed using the frit sintered body formed as described above. The frit after sealing had no bubbles or residue on the glossy surface. No bubbles or residues were observed between the glass surface and the surface.

As described above, even when acetic acid chill is used, a good frit glass sintered body can be obtained at a calcination temperature of 320 ° C., and good sealing can be performed at a sealing temperature of 350 ° C. using this. did it.

As a result of performing the sealing by using the low melting point frit glass in the above-mentioned examples, the above image display device was able to homogenize the electron source by reducing the thermal damage at the time of sealing. .

In each of the embodiments described above, acetone and ethyl acetate have been described as the organic substances to be mixed and stirred with frit glass and dry ice, but the organic substances are not limited thereto. As the ketones, isobutyl methyl ketone having a melting point of −85 ° C.,
Ethyl methyl ketone having a melting point of −86 ° C. can be used. Examples of ethers include diisopropyl ether having a melting point of -87.8 ° C., ethylene glycol monomethyl ether having a melting point of −85.1 ° C., ethylene glycol monoethyl ether having a melting point similar to that of ethylene glycol monomethyl ether, and t− having a melting point of −88 ° C. Butyl isopropyl ether can be used. As the esters, melting point-93.2.
℃ vinyl acetate, melting point-92 ℃ propyl acetate, melting point-
100 ° C. Pentyl acetate, melting point-93.3 ° C. ethyl butyrate, melting point −95 ° C. methyl butyrate and the like can be used. As alcohols, methanol having a melting point of -96 ° C, melting point of -1
14.5 ° C. ethanol, melting point −89.5 ° C. isopropyl alcohol, melting point −108 ° C. isobutyl alcohol, melting point −78.4 ° C. 1-pentanol (n-amyl alcohol) and the like can be used.

Since none of the above substances contain halogens or sulfides, they do not adversely affect the components forming the panel when the image display device is sealed. .

Of the above substances, ethyl acetate is more suitable for slurrying, so that the working conditions are good. For handling, methanol, ethanol and ethyl acetate are preferable, and acetone, ethyl acetate and methanol are preferable from the viewpoint of material cost.

In any case, what is important in the present invention is that it is an organic substance in a liquid phase in the temperature range where dry ice exists.

[0059]

Since the present invention is constructed as described above, it has the following effects.

In the method according to the first aspect, there is an effect that the sealing temperature at the time of heat molding of the frit glass made into a slurry can be made lower than the conventional temperature.

With the above effect, it becomes possible to perform the sealing of the image display device, which was conventionally unusable due to the problem of the temperature at the time of sealing, by using the frit glass made into slurry, The workability of the sealing process can be improved and the work can be performed without any problem in health management.

In the method according to the second aspect, since the step of applying the frit glass in the form of slurry is omitted and the properties of the finally formed frit glass are improved, the manufacturing cost of the sealed product is reduced. Claim 3 which has the effect of being able to do and can improve quality.
In the case of (1), the electron emission part and the electrode part of the image display device are less damaged by heat, and the frit glass powder is sealed so as not to scatter, so that the reliability can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a process of one embodiment according to the present invention.

FIG. 2 is a diagram showing a configuration of an image display device.

[Explanation of symbols]

 101 Low-melting frit glass powder 102 Dry ice powder 103 Insulation container 105 Slurry 106 Squeezer 107 Back plate 108 Frame 109 Sealed product 110 Mold 111 Low-melting frit glass sintered body

Claims (3)

[Claims] 1. A first step of mixing frit glass powder, powdered solid-phase carbon dioxide powder, and an organic substance that is in a liquid phase at the freezing point of carbon dioxide and stirring to form a slurry, and the first step And a second step of heating the slurry to a temperature at which the frit glass powder melts or higher and molding the slurry. 2. The frit glass molding method according to claim 1, wherein between the first step and the second step, the slurry obtained by the first step is heated to a temperature at which the frit glass powder is melted or below and molded. A frit glass molding method comprising performing a third step. 3. A face plate comprising a phosphor,
An image display device in which a back plate having an electron source for generating an electron beam is opposed to and sealed by frit glass, and the face plate and the back plate are sealed together. An image display device, which is produced by the frit glass molding method described in 1.