JP2004087429A - Flat panel display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reliable flat panel type display device whose sealed portion deviation and sealed portion sealing performance deterioration are prevented. <P>SOLUTION: A vacuum envelope 10 of the flat type display device has a rear plate 11 and a front plate 12 opposing each other. The vacuum envelope 10 also has a sealed portion 13 which seals peripheries of the front plate and the rear plate put together. A reinforcing portion 20 having a core harder than the sealed portion is formed at least in a part outside the sealed portion. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flat display device having a flat shape, and more particularly to a flat display device having a front substrate and a rear substrate which are arranged to face each other and are sealed to each other via a sealing portion.
[0002]
[Prior art]
2. Description of the Related Art In recent years, various flat display devices have been developed as next-generation lightweight and thin display devices that replace cathode ray tubes (hereinafter, referred to as CRTs). Such a flat display device includes a liquid crystal display (hereinafter, referred to as LCD) that controls the intensity of light by using the orientation of liquid crystal, and a plasma display panel (hereinafter, PDP) that emits a fluorescent material by ultraviolet rays of plasma discharge. ), A field emission display (hereinafter, referred to as FED) that emits a phosphor by an electron beam of a field emission type electron-emitting device, and a surface conduction electron emission display that emits a phosphor by an electron beam of a surface conduction electron-emitting device. (Hereinafter, referred to as SED).
[0003]
For example, an FED or SED generally has a front substrate and a rear substrate that are opposed to each other with a predetermined gap therebetween, and these substrates are joined to each other via a rectangular frame-shaped side wall and are surrounded by a vacuum. Make up the vessel. A phosphor screen is formed on the inner surface of the front substrate, and a number of electron-emitting devices (hereinafter, referred to as emitters) are provided on the inner surface of the rear substrate as electron emission sources for exciting the phosphor to emit light. Further, in order to support the atmospheric pressure load applied to the rear substrate and the front substrate, a plurality of support members are disposed between these substrates. The potential on the back substrate side is almost the ground potential, and the anode voltage Va is applied to the phosphor screen. Then, an image is displayed by irradiating the red, green, and blue phosphors constituting the phosphor screen with an electron beam emitted from the emitter to cause the phosphors to emit light.
[0004]
In such FEDs and SEDs, the thickness of the display device can be reduced to about several millimeters, and the weight and thickness have been reduced compared to CRTs currently used as displays for televisions and computers. can do.
[0005]
The display device as described above is disclosed in, for example, the following document.
K. Sakai, et al. , Euro Display, 18.3 L, pp 569-572, 1996.
M. Yamaguchi, et al. , SID Intl. Symp. Digest Tech. Papers, P52-55, 1997.
[0006]
[Problems to be solved by the invention]
In the above-described FED and SED, it is necessary to maintain the inside of the envelope at a high vacuum. Also, in a PDP, it is necessary to fill the discharge gas after the inside of the envelope is once evacuated. In an LCD, it is necessary to fill the envelope with liquid crystal. Accordingly, such an envelope has a configuration in which the periphery of the front substrate and the periphery of the rear substrate are hermetically sealed.
[0007]
On the other hand, various external forces act on the envelope. For example, when the flat display device is transported, turned over, or dropped, or leans on the display device, torsional or bending stress is generated in the envelope. It is also conceivable that distortion due to heat when the display device is driven or a sudden thermal shock due to the heat of the stove acts on the envelope. Therefore, the envelope is required to be resistant to being destroyed by these external forces.
[0008]
With respect to the two substrates constituting the envelope, the resistance can be increased relatively easily by increasing the thickness of the substrates or adding a reinforcing film or a reinforcing frame. In addition, with respect to the sealing portion, the durability can be increased by using a hard frit glass material or increasing the sealing width.
[0009]
In recent years, proposals have been made to use an adhesive or a low-melting metal material instead of a high-melting frit glass as a sealing material for the purpose of improving the characteristics of the flat-panel display device, reducing the cost, and reducing lead. I have. However, in an envelope using such a sealing material, the sealing portion becomes softer than a frit glass, a glass substrate, or the like. For this reason, there is a high possibility that the sealing portion is displaced by the stress acting on the envelope or the sealing property is deteriorated. In particular, in a flat panel display device having a large substrate thickness and robustness, or a flat panel display device such as an FED or SED having a large gap between two substrates, the stress acting on the sealing portion due to the bending of the envelope is reduced. growing.
[0010]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to provide a flat display device with improved reliability by preventing a displacement of a sealing portion and a deterioration in a sealing property.
[0011]
[Means for Solving the Problems]
In order to solve the above problem, a flat display device according to an aspect of the present invention includes a front substrate and a rear substrate that are arranged to face each other, and is located between the peripheral portions of the front substrate and the rear substrate. A sealing portion sealed with a sealing material, and a reinforcing portion provided outside at least a part of the sealing portion and having a core material harder than the sealing material. And
[0012]
Further, according to the flat display device according to the aspect of the present invention, the reinforcing portion has a structure in which a core material is embedded between the front substrate and the rear substrate via an adhesive material, or a front substrate or a rear substrate. A core material is fixed to one side with an adhesive material, and the other end surface of the rear substrate or the front substrate is received by the core material.
[0013]
According to the flat-panel display device configured as described above, by providing the reinforcing portion on the peripheral portion of the front substrate and the rear substrate outside the sealing portion, an external force acting on the peripheral portion of the substrate is applied by the reinforcing portion. External forces acting on the receiving and sealing portions can be significantly reduced. Thereby, even when an external force is applied, it is possible to prevent the displacement of the sealing portion and the deterioration of the sealing property, and obtain a flat display device with improved reliability and display characteristics.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which the present invention is applied to an FED as a flat display device will be described in detail with reference to the drawings.
As shown in FIGS. 1 and 2, the FED includes a transparent rectangular insulating substrate, for example, a back substrate 11 and a front substrate 12 made of a glass plate, and these substrates are opposed to each other with a predetermined gap. Are located. The rear substrate 11 and the front substrate 12 are sealed at their peripheral portions by a sealing portion 13 to form a flat rectangular vacuum envelope 10. The sealing portion 13 is formed in a rectangular frame shape, is located between the peripheral portions of the rear substrate 11 and the front substrate 12, and extends over the entire periphery of these substrates.
[0015]
A phosphor screen 16 is formed on the inner surface of the front substrate 12. The phosphor screen 16 is configured by arranging red, blue, and green phosphor layers and a black light-shielding layer. These phosphor layers are formed in stripes or dots. A metal back 17 made of aluminum or the like and functioning as an anode electrode is formed on the phosphor screen 16. A large number of electron-emitting devices 18 are provided in a matrix on the inner surface of the back substrate 11 and face the phosphor screen 16.
[0016]
Between the rear substrate 11 and the front substrate 12, a number of spacers 14 each having a plate shape or a column shape are arranged in order to maintain an interval between the substrates. The spacer 14 supports the atmospheric pressure load acting on these substrates by contacting the rear substrate 11 and the front substrate 12 at both ends thereof, and maintains the distance between the substrates at a predetermined value.
[0017]
The back substrate 11 and the front substrate 12 are each formed of, for example, a glass plate having a size of 30 to 50 "and a thickness of less than about 3 mm, and are opposed to each other by a spacer 14 with a gap of about 1 mm. And a low melting point metal material, for example, indium having a width of about 2 mm.
[0018]
Further, as shown in FIGS. 2 and 3, reinforcing portions 20 for reinforcing the sealing portion are provided on four sides of the rear substrate 11 and the front substrate 12 outside the sealing portion 13, respectively. Each reinforcing portion 20 has an elongated plate-shaped core material 22 and an adhesive material 24. The core member 22 is sandwiched and fixed between the peripheral portions of the rear substrate 11 and the front substrate 12 via the adhesive material 24, and extends along the corresponding side near the sealing portion 13. Here, each reinforcing portion 20 is arranged over substantially the entire length excluding the corners on each side of the substrate.
[0019]
Each core member 22 is formed of, for example, a glass rib having a rectangular cross section of about 0.8 mm in thickness and 6 mm in width. As the bonding material 24, for example, an inorganic adhesive is used. The adhesive material 24 is filled in the gap between the outer surface of the core material 22 and the rear substrate, the front substrate, and the sealing portion 13, and has a layer thickness of about 0.1 mm.
[0020]
In the FED having the above configuration, the electron emission element emits electrons toward the phosphor screen 16 by applying a voltage to the electron emission element 18 via the wiring formed on the rear substrate 11. Thereby, the phosphor layer of the phosphor screen 16 is excited to emit light, and an image is displayed.
[0021]
Next, a method of manufacturing the FED configured as described above will be described.
For example, when manufacturing a 36-inch TV FED, a glass plate having a thickness of less than 3 mm is prepared as the back substrate 11 and the front substrate 12. Then, the electron-emitting devices 18 and various wirings are formed on the rear substrate 11. Further, the spacer 14 is fixed on the rear substrate 11 in advance using a low melting point metal sealing material such as frit glass or indium. On the front substrate 12, a phosphor screen 16 and a metal back 17 made of an aluminum film are formed.
[0022]
Subsequently, indium having a width of 2 mm and a thickness of 1.0 mm is applied along the peripheral edge of the surface of one substrate, for example, the back substrate 11, to form the sealing portion 13. Here, indium is an excellent sealing material having a low melting point of 156 ° C. and extremely low outgassing even when heated in a vacuum, and hardly deteriorating the characteristics of the FED. As a sealing material for forming the sealing portion 13, in addition to indium, an alloy containing indium, or an inorganic or resin adhesive can be used.
[0023]
Next, the rear substrate 11 and the front substrate 12 prepared as described above are sealed in a vacuum chamber to form a vacuum envelope 10. That is, the back substrate 11 and the front substrate 12 are heated to release the surface adsorbed gas of each member, and these members are further washed with an electron beam. Subsequently, after the rear substrate 11 and the front substrate 12 are arranged in a vacuum chamber in a state where they are opposed to each other, indium forming the sealing portion 13 is electrically heated and sufficiently melted. In this state, the rear substrate 11 and the front substrate 12 are pressed in a direction approaching each other, and the peripheral portions of the rear substrate 11 and the front substrate 12 are sealed with the sealing portion 13 made of indium.
[0024]
Thereafter, the rear substrate 11 and the front substrate 12 are cooled, and the sealing portion 13 is solidified, thereby forming the vacuum envelope 10 of the FED. Next, on each side of the back substrate 11 and the front substrate 12, a predetermined amount of the adhesive material 24 is filled between the peripheral portions of the substrate, and then the core material 22 is pushed in and sandwiched between the peripheral portions of the substrate. In this state, the reinforcing material 20 is formed by curing the adhesive material 24. Through the above steps, an FED having the reinforcing portion 20 is obtained.
[0025]
According to the FED configured as described above, by providing the reinforcing portion 20 on the outer peripheral portion of the vacuum envelope 10 outside the sealing portion 13, the sealing is performed even when an external force acts on the vacuum envelope 10. The displacement of the portion 13 and the deterioration of the sealing property can be prevented, and the reliability can be improved.
[0026]
More specifically, the inorganic adhesive as the adhesive material 24 in the reinforcing portion 20 is a relatively hard material among the adhesives, but the hardness against the shearing force is the same as that of the sealing material if the adhesive area is the same. It is about the same as some indium. For this reason, in the reinforcing structure without the core member 22 made of glass rib which is harder than the sealing material or the bonding material, only the reinforcing effect of increasing the sealing width of the sealing portion can be obtained, and the sealing material formed of indium is used. The stress acting on the attachment portion 13 is not particularly reduced.
[0027]
According to the present embodiment, the hardness of the core material 22 constituting the reinforcing portion 20 with respect to the shearing force is about 2 to 20 times higher than that of the adhesive material 24. For this reason, the hardness of the entire reinforcing portion 20 in which the layer thickness of the adhesive material 24 is about 0.1 mm is significantly higher than that of the sealing portion 13. Therefore, most of the shear stress acting on the peripheral portions of the back substrate 11 and the front substrate 12 is concentrated only on the hard reinforcing portion 20, and almost no shear stress is applied on the sealing portion 13 formed of soft indium with respect to the reinforcing portion 20. Will not work.
[0028]
As described above, most of the stress that has been acting on the sealing portion 13 acts on the hard reinforcing portion 20 in a concentrated manner. Therefore, it is desirable that the reinforcing portion 20 is made of a material that does not yield and has a certain amount of bonding area. According to the present embodiment, the reinforcing portion 20 has an adhesive width of about 5 to 6 mm over each side of the substrate, and as a result, it is possible to obtain practically sufficient flexural strength.
[0029]
From the above, according to the FED according to the present embodiment, the sealing portion 13 can be effectively reinforced by a simple configuration in which the reinforcing portion 20 is provided, and the external force acts on the vacuum envelope 10. However, it is possible to prevent the displacement of the sealing portion 13 and the deterioration of the sealing property. Thereby, the airtightness of the sealing portion 13 is high, the positional displacement between the rear substrate 11 and the front substrate 12 can be prevented, and an FED with improved reliability and display characteristics can be obtained.
[0030]
Note that the core material 22 of the reinforcing portion 20 can obtain a reinforcing effect as long as it is formed of a material that is at least harder than the sealing portion 13 and the adhesive material 24. A desired hardness can be obtained even with this configuration.
[0031]
Further, the adhesive material 24 of the reinforcing portion 20 is not limited to the above-mentioned inorganic adhesive, and a resin-based material such as epoxy, a material obtained by adding a filler such as silica or alumina to the material, or the like can generally obtain desired hardness and reinforcing effect. be able to.
[0032]
The formation region of the reinforcing portion 20 is not limited to the above-described embodiment, and may be provided over the entire periphery of the substrate outside the sealing portion 13. Further, the reinforcing portion 20 is not limited to the four sides of the rear substrate and the front substrate, but can be provided with a reinforcing effect if provided along at least one side.
[0033]
Further, as in the second embodiment shown in FIG. 4, a configuration may be employed in which a plurality of reinforcing portions 20 are intermittently provided on each side of the rear substrate 11 and the front substrate 12. Also in this case, the operation and effect can be obtained in the same manner as in the above-described first embodiment.
[0034]
According to the third embodiment shown in FIGS. 5 and 6, the core material 22 constituting each reinforcing portion 20 includes the filling portion 26 for filling the adhesive surface with the adhesive material 24. A plurality of filling portions 26 are provided for each core material 22 and are arranged at intervals in the longitudinal direction of the core material. Here, each filling portion 26 has a pair of through holes 28a and 28b extending in a direction orthogonal to the longitudinal direction of the core material 22 and orthogonal to each other. The core 22 is sandwiched and fixed between the peripheral portions of the rear substrate 11 and the front substrate 12 via the adhesive material 24, and extends along the side of the substrate near the sealing portion 13.
[0035]
When forming the reinforcing portion 20 having the above-described configuration, first, on each side of the rear substrate 11 and the front substrate 12, a core material 22 is loaded between the peripheral portions of the substrate. After that, the adhesive material 24 is injected from the through holes 28a and 28b of each filling portion 26 and guided to the adhesive surface. That is, the gap between the outer surface of the core member 22 and the rear substrate, the front substrate, and the sealing portion 13 is filled with the adhesive material 24 through the filling portion 26. Thereafter, the reinforcing material 20 is formed by curing the adhesive material 24.
[0036]
According to the FED having the above-described structure, since the core material 22 of the reinforcing portion 20 includes the filling portion 26, the core material is loaded between the peripheral portions of the rear substrate 11 and the front substrate 12 and then the adhesive material 24 is passed through the filling portion. Can be filled in the adhesive surface. In this case, the thickness of the adhesive material 24 located in the gap between the outer surface of the core member 22 and the rear substrate, the front substrate, and the sealing portion 13 is formed to be thinner than that of the first embodiment. It is possible to do. And the core material 22 can be enlarged by an amount corresponding to the thinning of the adhesive material layer, and the reinforcing effect by the reinforcing portion 20 can be further improved.
[0037]
In the third embodiment, other configurations are the same as those of the first embodiment, and the same portions are denoted by the same reference characters and will not be described in detail. Further, in the third embodiment, the same operation and effect as those of the first embodiment can be obtained.
[0038]
When the length of the reinforcing portion 20 is short, at least one filling portion 26 may be provided. Each filling portion 26 has at least one outlet opening in a gap between the outer surface of the core member 22, the back substrate, the front substrate, and the sealing portion 13, and an opening outside the vacuum envelope 10. And at least one inlet. Further, the filling portion 26 is not limited to the above-described through hole, and may be configured by a groove formed on the surface of the core member 22.
[0039]
Next, an FED according to a fourth embodiment of the present invention will be described. In the above-described embodiment, the core material of each reinforcing portion is fixed by being sandwiched between the peripheral portions of the back substrate 11 and the front substrate 12 via the adhesive material 24, and along the side of the substrate near the sealing portion 13. Extending. On the other hand, according to the present embodiment, the reinforcing portion 20 is provided at each corner of the vacuum envelope 10. Each reinforcing portion 20 has a core material 22 bent substantially in an L shape. The core material 22 is disposed outside the sealing portion 13 so as to face the surface of the rear substrate 11 and the corner of the front substrate 12, and is located in a gap between the substrate and the sealing portion and the core material. Is fixed by the adhesive material 24. The other configuration is the same as that of the above-described first embodiment, and the same portions are denoted by the same reference numerals and detailed description thereof will be omitted.
[0040]
According to the fourth embodiment, the relationship between the front substrate 12 and the reinforcing portion 20 is not a shear but a compression (tensile) relationship. A sufficient yield strength can be ensured even with a small area. In addition, the strength of the back substrate 11 and the reinforcing portion, which is to be sheared, is enhanced by utilizing the large area of the corner on the rear substrate 11 where no drive wiring or the like is present, so that the reinforcing portion 20 reinforces only the substrate corner. However, a sufficient reinforcing effect can be obtained. Therefore, also in the fourth embodiment, it is possible to obtain substantially the same operation and effect as in the first embodiment.
[0041]
In addition, the reinforcement part 20 should just be provided facing at least two across one board | substrate. Moreover, it is not limited to a corner | angular part, Even if it is provided adjacent to the edge | side of a board | substrate, a reinforcement effect is exhibited. be able to. Also in the fourth embodiment, the above-described filling portion for filling the bonding surface with the bonding material is provided in each core material 22, and after the core material is arranged at a predetermined position with respect to the substrate, the bonding material is removed. It is good also as a structure filled.
[0042]
Further, in the above-described first to fourth embodiments, the sealing portion 13 that seals the peripheral portions of the back substrate 11 and the front substrate 12 is not limited to the sealing material, and as shown in FIG. For example, a frame-shaped side wall 30 made of glass and a sealing material 32 may be combined.
[0043]
In addition, the present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention. For example, the present invention is not limited to FEDs, but can be applied to other flat display devices such as SEDs and PDPs. Further, the size, shape, and the like of each component can be variously modified as needed. In particular, the shape of the core material constituting the reinforcing portion is not limited to a plate having a rectangular cross section, but may be any shape.
[0044]
【The invention's effect】
As described above in detail, according to the present invention, the sealing portion can be effectively reinforced with a simple configuration, and the displacement of the sealing portion and the deterioration of the sealing property can be prevented, and the reliability is improved. A display device can be provided.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an FED according to a first embodiment of the present invention.
FIG. 2 is a sectional view of the FED taken along line AA in FIG. 1;
FIG. 3 is a plan view of the FED.
FIG. 4 is a plan view schematically showing a part of an FED according to a second embodiment of the present invention.
FIG. 5 is a plan view schematically showing a part of an FED according to a third embodiment of the present invention.
FIG. 6 is a sectional view of the FED taken along line BB in FIG. 5;
FIG. 7 is a plan view showing an FED according to a fourth embodiment of the present invention.
FIG. 8 is a sectional view taken along line CC of FIG. 7;
FIG. 9 is a sectional view showing an FED according to still another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Vacuum envelope 11 ... Back board 12 ... Front board 13 ... Sealing part 14 ... Spacer 16 ... Phosphor screen 17 ... Metal back layer 18 ... Electron emission element 20 ... Reinforcement part 22 ... Core material 24 ... Adhesive material 26 ... filling section

Claims (13)

A front substrate and a rear substrate which are arranged to face each other,
A sealing portion which is located between the peripheral portions of the front substrate and the rear substrate and seals these peripheral portions with a sealing material,
A reinforcing portion having a core material that is provided outside at least a part of the sealing portion and is harder than the sealing material,
A flat-panel display device comprising: The flat display device according to claim 1, wherein a core material of the reinforcing portion is fixed between peripheral portions of the front substrate and the rear substrate via an adhesive material. The flat panel display according to claim 2, wherein the reinforcing portion is provided over substantially the entire length of at least one side of the front substrate and the rear substrate. The flat display device according to claim 2, wherein a plurality of the reinforcing portions are provided intermittently along at least one side of the front substrate and the rear substrate. A core material of the reinforcing portion is opposed to a surface of one of the front substrate and the rear substrate and a side edge of the other substrate, and is fixed to the surface and the edge via an adhesive material. The flat display device according to claim 1. 6. The flat panel display according to claim 5, wherein a plurality of core members of the reinforcing portion are provided so as to face each other at a plurality of positions on a side edge of the other substrate. The core material has a filling portion for guiding an adhesive material supplied from outside the front substrate and the rear substrate to an adhesive surface between the front substrate and the rear substrate and the core material. The flat display device according to any one of claims 2 to 6, wherein The flat display device according to claim 1, wherein the core is formed of one of glass, ceramics, and metal. 9. The flat display device according to claim 1, wherein the adhesive material is one of an inorganic adhesive and a resin adhesive. The flat display device according to any one of claims 1 to 9, wherein the sealing material is one of an adhesive and a low melting point metal. The flat display device according to claim 1, wherein the sealing material is a low-melting metal material containing indium or an indium alloy. The flat display device according to any one of claims 1 to 11, wherein a gap between the front substrate and the rear substrate is 1 mm or more. A phosphor screen formed on the inner surface of the front substrate, a plurality of electron emission sources provided on the back substrate to excite the phosphor screen, and a plurality of spacers provided between the front substrate and the back substrate; The flat display device according to claim 1, further comprising:

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