JP2004354830A - Display device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device with improved productivity and its manufacturing method that enable speedy and stable sealing operation by using a resin-based bonding material and low-fusion-point glass. <P>SOLUTION: An envelope 10 of the display device has a sealed part, sealed with the resin-based bonding material 13, at least partially and the resin-based bonding material has conductivity. In the sealing, the resin-based bonding material is electrified to heat up, and thus thermally cured for sealing. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display device having an envelope at least partially sealed, and a method for manufacturing the same.
[0002]
[Prior art]
As a display device for displaying an image table, a cathode ray tube (hereinafter, referred to as CRT), a liquid crystal display (hereinafter, referred to as LCD), a plasma display panel (hereinafter, referred to as PDP), a field emission display (hereinafter, referred to as FED) And surface conduction electron emission displays (hereinafter, referred to as SEDs). These display devices usually have an envelope for accommodating the display element, and at least a part of the envelope is sealed with a sealing material.
[0003]
For example, in an LCD, an envelope is formed by sealing peripheral portions of two substrates with a resin-based adhesive. In this case, generally, a substrate having an epoxy resin adhesive printed and applied to its periphery is attached to the substrate, and the entire substrate is heated to a temperature of 100 ° C. or more in a heating furnace and maintained for a predetermined time to thermally cure the adhesive. It is sealed.
[0004]
In PDPs, FEDs, SEDs, and CRTs, the envelope and the exhaust pipe are sealed with frit glass. In this case, after frit glass is printed or applied to the sealing portion of the substrate or the like, and the substrate or the like is heated to a temperature of about 350 to 450 ° C. in a heating furnace to soften and melt (and possibly crystallize) the frit glass. , Cooled and solidified.
[0005]
In the above sealing process, it was necessary to heat and maintain the entire envelope at a predetermined temperature. Therefore, there are problems such as the necessity of a large-scale heating device, the deterioration of the alignment accuracy due to the thermal expansion of the substrate, and the prolongation of the heating and cooling times. It has become.
[0006]
As a method of solving this problem, the sealing portion of the envelope is filled with a low-melting metal sealing material such as indium that melts at a relatively low temperature, the conductive sealing material is energized, and the conductive sealing is performed by Joule heat. A method (hereinafter referred to as energizing heating) of bonding and heating the substrate itself by heating and melting itself has been studied (for example, see Patent Document 1). According to this method, the envelope can be sealed by applying only necessary minimum heating to the sealing portion, and the above problem is reduced.
[0007]
[Patent Document 1]
JP-A-2002-319346
[Problems to be solved by the invention]
However, resin-based adhesives and low-melting-point glass, which are widely used as sealing materials, are insulators, so that the technology of energization heating and sealing cannot be applied.
[0009]
The present invention has been made in view of the above points, and an object of the present invention is to provide a display device capable of performing a sealing operation quickly and stably using a resin-based adhesive or a low-melting glass, and having improved productivity. And a method of manufacturing the same.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, the display device according to the embodiment of the present invention has a configuration in which the resin-based adhesive or the low-melting glass itself has conductivity.
That is, the display device according to an embodiment of the present invention includes an envelope having at least a part of a sealing portion sealed with a low-melting glass material, and the low-melting glass material has conductivity. It is characterized by:
Further, a display device according to another aspect of the present invention includes an envelope having at least a part of a sealing portion sealed with a resin-based adhesive, wherein the resin-based adhesive has conductivity. It is characterized by having.
[0011]
A method for manufacturing a display device according to an embodiment of the present invention is a method for manufacturing a display device including an envelope at least partially sealed with a low-melting glass material having conductivity,
A low-melting-point glass material is placed in the sealing portion of the envelope, and the low-melting-point glass material placed is heated by being energized to soften and melt the low-melting-point glass for sealing.
[0012]
According to another aspect of the present invention, there is provided a method of manufacturing a display device including an envelope at least partially sealed with a conductive resin-based adhesive. It is characterized in that a resin-based adhesive is disposed in a sealing portion of a vessel, and the resin-based adhesive disposed above is heated by being energized, and the resin-based adhesive is thermally cured to be sealed.
[0013]
According to the display device having the above-described configuration and the method for manufacturing the same, the energization heating technique can be applied to sealing using a resin-based adhesive or a low-melting glass material, and the productivity of the display device can be increased. it can.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which a display device according to the present invention is applied to an LCD as a flat display device will be described in detail with reference to the drawings.
As shown in FIGS. 1 and 2, the LCD includes an envelope 10. The envelope 10 has a pair of substrates 11 and 12 which are opposed to each other with a predetermined gap therebetween, and the peripheral portions of these substrates are adhered to each other and sealed by a resin-based adhesive 13 having conductivity. It constitutes a wearing part. A liquid crystal layer 14 is sealed between the substrates 11 and 12. The adhesive 13 is formed in a frame shape along the peripheral edges of the substrates 11 and 12, and the pair of ends 13 a face each other with a gap therebetween and define a liquid crystal injection port 17. After injecting the liquid crystal, the liquid crystal injection port 17 is sealed with a sealing material 18 made of, for example, an ultraviolet curable resin adhesive. A pixel electrode (not shown), a switching element, and a plurality of wirings are provided on an inner surface of the substrate 11, and a counter electrode (not shown) is provided on an inner surface of the substrate 12.
[0015]
Next, a method of manufacturing the LCD having the above configuration will be described. First, substrates 11 and 12 on which electrodes, wirings, and the like are respectively formed are prepared, and an adhesive 13 is printed and applied in a frame shape along the periphery of one of the substrates. Subsequently, after the substrates 11 and 12 are aligned with each other, they are bonded to each other with the adhesive 13. At this time, as shown in FIG. 3, the substrates 11 and 12 are sandwiched by the pressing device 15 and pressurized at a predetermined pressure in a direction approaching each other. Further, on the outer surface of each of the substrates 11 and 12, a region facing the adhesive 13, that is, a region outside the sealing portion is covered with the annular heat insulating portion 16. The heat insulating part 16 is for preventing heat from escaping due to the atmosphere or heat transfer when the adhesive 13 is heated by energizing heating described later, and is formed of a material such as ceramics having low heat conductivity and low specific heat.
[0016]
In this state, as shown in FIG. 4, a power supply unit 19 is connected to two ends 13a of the resin-based adhesive 13 defining the liquid crystal injection port 17, and a current is supplied from these ends to the adhesive 13. To heat the adhesive.
[0017]
Here, the adhesive 13 is made of an epoxy resin as a base material, and a suitable amount of 70% by weight of silver and 20% by weight of carbon of resin solids, and a curing agent and a 5 μm spacer member (particles of silica, alumina, etc.) in advance. One-part adhesive composition was used. The reason for blending carbon is to achieve low low efficiency with as little conductive filler as possible. When only silver is added, the minimum amount required to form a conductive path increases, and the adhesive strength and airtightness of the adhesive deteriorate. However, by blending an appropriate amount of carbon having excellent dispersibility in the resin, it is possible to secure conductivity between silver powders with a small amount of added silver, and as a result, to improve the adhesive strength and airtightness of the sealing portion. ing. The resistivity of the adhesive 13 is about 1 × 10 ⁻² to 1 × 10 ⁻³ Ωcm.
[0018]
The cross section of the adhesive 13 in a state where the substrates 11 and 12 are pressed has a width of 10 mm and a thickness of 5 μm. The temperature of the adhesive 13 is increased from room temperature to 120 ° C. by applying electric current, and is maintained at 120 ° C. for 30 minutes. In the present embodiment, since the appropriate heat insulating treatment is performed by the heat insulating portion 16, the sealing including the adhesive 13 is performed by applying power of about 1 W (approximately 0.2 to 2 A in terms of a conduction current) per 1 cm of the sealing portion. The temperature of the part reaches 120 ° C. in 1-3 minutes.
[0019]
While measuring the temperature of the sealing portion with a thermocouple installed in the heat insulating portion 16, the power is supplied as much as necessary to maintain the adhesive 13 at 120 ° C., and the adhesive is thermally cured, and then the energization is stopped. I do. At the same time as the power supply is stopped, the heat insulating portion 16 is separated from the substrates 11 and 12. Next, the surfaces of the substrates 11 and 12 are air blow cooled. Thus, the peripheral portions of the substrates 11 and 12 are sealed with each other, and the substrates 11 and 12 are sufficiently cooled in about 1 to 2 minutes after the power is stopped, so that the substrates can be discharged to the next step.
[0020]
As described above, according to the present LCD and the method of manufacturing the same, a resin-based adhesive having conductivity is used, and the adhesive is heated by energizing to seal the substrates 11 and 12. This eliminates the need for a conventional large heating furnace for heating the entire substrate, and can reduce the time required for heating and cooling to several minutes. At the same time, the deterioration of the alignment of the substrate due to thermal expansion is reduced.
[0021]
In the above-described embodiment, an epoxy resin-based adhesive has been described, but other adhesives such as a polyimide or polyamide resin-based adhesive, an acrylic resin-based or inorganic adhesive can be similarly applied. Although silver and carbon are used as additives for imparting conductivity to the adhesive, fine particles of metal such as nickel, copper, gold, and stainless steel may be used, and the shape may be arbitrarily selected, such as granular or flake. Can be.
[0022]
In the present embodiment, a pair of ends of the adhesive 13 defining the liquid crystal injection port 17 is used as a current-carrying electrode. However, the liquid crystal injection port is formed by an appropriate hole formed in the substrate, and the sealing portion is formed. May be a frame-like structure without any break. In this case, for example, outwardly projecting portions may be formed at two opposing corners of an adhesive applied and formed in a rectangular frame shape, and these projecting portions may be used as electrodes for energization.
[0023]
Next, a PDP according to a second embodiment of the present invention will be described.
As shown in FIGS. 5 and 6, the PDP includes an envelope 20. The envelope 20 has a pair of substrates 21 and 22 opposed to each other with a predetermined gap therebetween, and the peripheral portions of these substrates are separated from each other by a frit glass material 23 having conductivity as a low melting glass material. They are bonded together to form a sealing part. The frit glass material 23 is applied in a frame shape along the peripheral edges of the substrates 21 and 22, and has a pair of protrusions 24 protruding outward from two opposing corners. On the inner surface of one substrate 21, a number of partitions, phosphors, wirings, etc., not shown, are provided. On the inner surface of the other substrate 22, cathodes, display electrodes, etc., not shown, are provided.
[0024]
Next, a method of manufacturing the PDP having the above configuration will be described. First, substrates 21 and 22 on which partitions, phosphors, wirings, and the like are formed are prepared, and frit glass material 23 is printed and applied in a frame shape along the periphery of one of the substrates. Subsequently, after the substrates 21 and 22 are aligned with each other, they are bonded to each other with the frit glass material 23. At this time, as shown in FIG. 6, the peripheral portions of the substrates 11 and 12 are clamped by the clamper 25 and pressurized at a predetermined pressure in a direction approaching each other. In this state, as shown in FIG. 7, a power supply unit 29 is connected to the pair of protrusions 24 of the frit glass material 23, and a current is applied to the frit glass material 23 from these protrusions to soften the frit glass material. Let melt. Thus, the peripheral portions of the substrates 21 and 22 are sealed with the frit glass material 23 to form a sealed portion.
[0025]
The frit glass material 23 had a composition containing 50 to 90% by weight of frit glass and stainless steel powder. The amount of the conductive filler to be added needs to be an optimum configuration in accordance with the frit composition. When the amount of the conductive filler is small, the formation of the conductive path is insufficient, and when the amount is too large, the airtightness of the sealing portion is deteriorated. At the same time, the coefficient of thermal expansion of the frit glass material 23 and the substrates 21 and 22 are adjusted by adjusting the stainless steel powder diameter and the frit composition. The resistivity of the frit glass material 23 is about 1 × 10 to 1 × 10 ² Ωcm.
[0026]
The cross section of the frit glass material 23 when the substrates 21 and 22 are pressed is 8 mm in width and 0.2 mm in thickness. When the substrates 21 and 22 are heated to 350 ° C. in a heating furnace and a current of 0.3 to 1 A is applied from the protruding portion 24 of the frit glass material 23, the frit glass material reaches 400 ° C. in about 3 to 5 minutes. Saturated. After that, the power is stopped for 15 minutes. Thereby, the peripheral portions of the substrates 21 and 22 are sealed.
[0027]
As described above, according to the present PDP and the method for manufacturing the same, the frit glass material having conductivity is used, and the frit glass material is electrically heated to seal the substrates 21 and 22. This eliminates the need for a conventional large heating furnace for heating the entire substrate, and can reduce the time required for heating and cooling to several minutes. At the same time, the deterioration of the alignment of the substrate due to thermal expansion is reduced.
[0028]
In the second embodiment, stainless steel powder is used as an additive for imparting conductivity to the frit glass. However, other metal powders may be used. It may be your body. In the case of a metal powder or a powder having a metallized surface, the conductivity depends on the network of the metal. However, the conductive mechanism is not limited to this, and another conductive mechanism may be used.
[0029]
For example, the resistivity of a glass material has a temperature dependence in which the resistivity decreases as the temperature rises. Below the glass transition temperature, the index of the resistivity is substantially proportional to the index, and at a temperature of 100 ° C., the resistivity is approximately 1%. / 100. Generally, the softening and melting temperature of the low melting point glass material is as high as 350 to 450 ° C., and the base temperature of the electric heating is set to a high temperature close to the softening and melting temperature so as not to generate stress due to a difference in thermal expansion. As described above, the electric resistance of the glass material itself may be reduced by increasing the base temperature at the time of sealing. Alternatively, by additionally using the temperature dependence of the glass material, the amount of the conductive filler to be added can be reduced.
[0030]
Regarding the resistivity of the glass material, by adding a large amount of an oxide of an alkali metal having a small element number, such as Li, Na, and K, which easily ionizes and diffuses in the glass, the resistance of the low melting glass material at a high temperature of about 400 ° C. The rate can be reduced to 1 × 10 ³ to 1 × 10 ⁵ Ωcm. Further, by adding an oxide such as Sn, Sb, In, or Ru, the resistivity of the low-melting glass material can be reduced to 1 × 10 Ωcm or less.
[0031]
However, these conductive mechanisms are the movement of alkali metal ions and the movement of holes in crystal defects, and thus the conductive carrier is basically localized in the sealing material. For this reason, if a direct current is continuously supplied to the low melting point glass material having the above-described conductive mechanism, current depletion and stress increase due to carrier movement are caused. Therefore, in the case where the low-melting-point glass material is used as a sealing material and heated by energization, it is preferable to use alternating current to prevent the carrier from being biased. On the other hand, if the resistance of the sealing material is too high, the voltage required for energization becomes high, which causes a discharge breakdown of an adjacent wiring array and an increase in a device withstand voltage design burden. Practically, the upper limit of the sealing material resistivity at the time of sealing is 1 × 10 ⁴ Ωcm.
[0032]
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements in an implementation stage without departing from the scope of the invention. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Further, components of different embodiments may be appropriately combined.
[0033]
For example, in the above-described embodiments, LCDs and PDPs have been described. However, the present invention can be applied to other flat display devices such as FEDs and SEDs, or display devices such as CRTs. Further, the sealing portion of the envelope is not limited to the peripheral portion of the substrate, and may have a configuration in which the sealing portion joins between the substrate and the frame or between the envelope and the exhaust pipe. .
[0034]
【The invention's effect】
As described above, according to the present invention, it is possible to perform a sealing operation quickly and stably using a resin-based adhesive or a low-melting glass, and to provide a display device with improved productivity and a method of manufacturing the same. can do.
[Brief description of the drawings]
FIG. 1 is a plan view showing an LCD according to a first embodiment of the present invention.
FIG. 2 is a sectional view of the LCD.
FIG. 3 is a cross-sectional view showing a step of bonding and pressing a pair of substrates in the manufacturing process of the LCD.
FIG. 4 is a plan view schematically showing a step of energizing and heating a resin adhesive applied and printed on a sealing portion of a substrate in the LCD manufacturing process.
FIG. 5 is a plan view showing a PDP according to a second embodiment of the present invention.
FIG. 6 is a sectional view of the PDP.
FIG. 7 is a plan view schematically showing a step of conducting and heating a resin-based adhesive applied and printed on a sealing portion of a substrate in the PDP manufacturing process.
[Explanation of symbols]
10 ... envelope, 11, 12, 21, 22 ... board,
13 resin adhesive, 23 frit glass,

Claims (18)

A display device comprising: an envelope having at least a part of a sealing portion sealed with a low-melting glass material, wherein the low-melting glass material has conductivity. 2. The display device according to claim 1, wherein the resistivity of the low-melting glass material at the time of sealing is smaller than 1 × 10 ⁴ Ωcm. The display device according to claim 1, wherein the low-melting glass material contains fine particles of carbon or metal. The display device according to claim 1, wherein the low-melting glass material contains at least one of Sn, Sb, In, and Ru. 4. The display device according to claim 1, wherein the low-melting glass material contains at least one of Li, Na, and K. 5. The display according to any one of claims 1 to 5, wherein the envelope includes a pair of substrates arranged to face each other, and a peripheral portion of the substrate is sealed by the sealing portion. apparatus. A display device, comprising: an envelope having at least a part of a sealing portion sealed with a resin-based adhesive, wherein the resin-based adhesive has conductivity. The display device according to claim 7, wherein the resin-based adhesive contains carbon or metal fine particles. The display according to any one of claims 1 to 5, wherein the envelope includes a pair of substrates arranged to face each other, and a peripheral portion of the substrate is sealed by the sealing portion. apparatus. In a method for manufacturing a display device including an envelope at least partially sealed by a low-melting glass material having conductivity,
Placing a low-melting glass material in the sealing part of the envelope,
A method for manufacturing a display device, characterized in that the low-melting glass material arranged is heated by energizing, and the low-melting glass is softened and melted and sealed. The method of manufacturing a display device according to claim 10, wherein the direction of a current supplied to the low-melting glass is changed with time. 13. The display device according to claim 10, wherein the envelope is heated to a temperature close to the softening and melting temperature of the low-melting glass material, and the low-melting glass material is heated and softened by energizing the low-melting glass material. Method. The method of manufacturing a display device according to claim 10, wherein the resistivity of the low-melting glass material at the time of sealing is smaller than 1 × 10 ⁴ Ωcm. 14. The method for manufacturing a display device according to claim 10, wherein the low melting point glass material contains fine particles of carbon or metal. 14. The method according to claim 10, wherein the low-melting-point glass material contains at least one of Sn, Sb, In, and Ru. The method according to any one of claims 10 to 13, wherein the low-melting glass material contains at least one of Li, Na, and K. In a method of manufacturing a display device having an envelope at least partially sealed by a resin-based adhesive having conductivity,
Placing a resin adhesive in the sealing part of the envelope,
A method for manufacturing a display device, characterized in that a current is applied to the resin-based adhesive disposed above to heat the resin-based adhesive, and the resin-based adhesive is thermally cured and sealed. 18. The method according to claim 17, wherein the resin-based adhesive contains fine particles of carbon or metal.

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