The present invention relates to an image display device, and more particularly to an image display device which is provided with a support body which is interposed between substrates and surrounds a sealed space.
As an image display device which exhibits excellent properties such as high brightness and high definition, a color cathode ray tube has been popularly used conventionally.
Further, along with the enhancement of the quality of an information processing equipment and television broadcasting in recent years, there has been a demand for a panel display which is a light-weighted and space-saving image display device while possessing excellent properties such as high brightness and high definition.
As a typical example, a panel display such as a liquid crystal display device, a plasma display device or the like has been commercialized.
With respect to this type of panel display, as a display device which is capable of exhibiting particularly high brightness, various types of panel displays such as a field (electron) emission display device and an organic EL display device which is characterized by low power consumption have been proposed.
Among these panel-type display devices, in a display device, which defines a sealed space between two substrates consisting of a face substrate and a back substrate and sets the pressure inside the sealed space lower than an external atmospheric pressure or evacuates the sealed space, a frame-like support body is arranged to hold a gap between two substrates at a given value and maintains the hermetic property by surrounding the sealed space.
The image display device includes field-emission-type electron sources 5, control electrodes and the like on an inner surface of the back substrate 1. The image display device also includes an anode and a phosphor layer 6 on an inner surface of the face substrate 2. Further, numeral 7 indicates spacers and these spacers 7 are provided for maintaining a distance between both substrates within the above-mentioned display region. These spacers 7 are indispensable these days along with the large-sizing or the increase of the display screen.
The back substrate 1 is formed of preferably a material such as glass or ceramic, while the face substrate 2 is formed of a light-transmitting material such as glass. Further, the support body 3 is formed of preferably a material such as glass or ceramics and is fixedly secured to the inner peripheries of the back substrate 1 and the face substrate 2 using the sealing material such as frit glass. The inner space defined by the back substrate 1, the face substrate 2 and the support body 3 is evacuated to create the degree of vacuum of, for example, 10−5 to 10−7 Torr.
Further, the above-mentioned electron sources 5 are constituted of, for example, carbon nanotubes (CNT), diamond-like carbon (DLC) or other field emission cathode.
In such a panel display, with respect to the support body which surrounds the display region while holding the distance between both substrates, there has been known the above-mentioned support body which is integrally formed and a support body which is shown in
In the display device shown in
In
On respective portions of the respective wall members 3X1, 3X2, 3Y1, 3Y2 and the 3C1 to 3C4 which are arranged close to each other and are also engaged with each other, oblique surfaces 3P are formed. Further, a crossing angle between a normal line which is erected from the oblique surface 3P and a normal line which is erected from the back substrate 1 or the face substrate 2 is set to an acute angle.
Further,
Numerals in the drawing indicate parts which are identical with the parts shown in
As shown in
Further, JP-A-2000-311630 describes a technique in which a support body includes a first frame member which encloses electron emission elements and a second frame member which encloses the first frame member, these first and second frame members are formed by arranging, positioning and fixing a plurality of plate-like members in a rectangular shape, melting respective contact portions by heating with a burner thus joining the contact portions by welding.
Still further, JP-A-11-317164 discloses a technique on an image forming device having an integral-structure-type support frame, wherein by providing the sealing between a face plate and spacers, between a back plate and the spacers and between the support frame and both of front plate and back plate using frit glasses which have different softening points, the number of sealing can be reduced and hence, the size change can be minimized whereby the occurrence of minute leaking of liquid crystal can be suppressed.
In the above-mentioned related art, with respect to the display device to which two glass plates are adhered and fixed to by way of the integrally formed frame type support body, when the display device becomes large sized (large sizing of the screen), the support body is liable to be easily broken at the time of handling thereof. Further, waste members are produced at the time of producing materials of constituting parts thus giving rise to a drawback that a manufacturing cost is pushed up.
To avoid such a drawback, there has been also proposed a technique as shown in
This assembling and adhering has an advantage that the assembling and adhering can also overcome the drawback on breaking compared to the integrally-formed-frame-type support body and, at the same time, can avoid the occurrence of waste members at the time of taking materials of members thus realizing the reduction of cost.
However, at the time of sealing both substrates and the support body by way of the sealing material, a load is applied to both substrates respectively in the direction perpendicular to plate surfaces (Z direction) . At the time of performing this adhesion under pressure, the joining portions of respective divided members of the support body are displaced in the directions (X, Y directions) in which the joining portions are spaced apart from each other and hence, the maintenance of hermetic property or air tightness of the joining portions becomes insufficient leading to the occurrence of leaking of liquid crystal. Accordingly, the use of a jig for preventing the occurrence of leaking becomes indispensable.
Further, the high-temperature atmosphere is generated even in the evacuation step after sealing, and hence, there exists a possibility that an adhesive material of the joining portion melts thus giving rise to a drawback that it is necessary to reuse a jig which restricts the displacement of respective divided members of the support body. The solution of this drawback has been one of the tasks of this technical field.
Further, in the technique of the related art in which the plurality of plate-like members are arranged in a rectangular shape and are positioned and fixed, and the respective contact portions are heated and melt by burners thus forming the support body by welding, in view of the fact that the technique inevitably requires a shaping step to cope with the occurrence of the deformation attributed to welding, the drawback on an operational environment attributed to heating by burners and operational efficiency and the like, the adoption of the related art is avoided and the technique which fixes members of the support body using the adhesive material has been favorably used.
Accordingly, the present invention has been made to overcome the above-mentioned conventional drawbacks and can solve the above-mentioned drawbacks by providing an image display device which performs hermetic sealing of end surfaces of a support body and a face substrate and a back substrate using a sealing material, wherein the support body is constituted of a mass of a plurality of support body members and the support body members are hermetically bonded to each other using a bonding material which differs from the sealing material.
Accordingly, the leaking of liquid crystal is hardly generated and hence, it is possible to provide the image display device which can perform a desired high quality display and also can easily realize the large-sizing of the screen for display image.
According to the present invention, by separately using the sealing material and the bonding material for different purposes, it is possible to ensure the hermetic bonding between the support body members and hence, it is possible to obviate the possibility of the occurrence of leaking of liquid crystal thus realizing the acquisition of the large-sized (large-screen) display device with the high definition.
Further, since the support body is constituted of the mass of the plurality of support body members, a defect on rupture which has been the drawback of the integrally formed support body can be overcome. Further, it is also possible to obviate the waste material with respect to the preparation of materials for support body members and hence, the support body can be manufactured at a low cost thus realizing the acquisition of the large-sized (large-screen) display device with the high definition.
According to the present invention, the displacement between the support body members is hardly generated at the time of performing the sealing, the evacuation and the like and hence, the hermetic property can be ensured whereby the use of the above-mentioned jig is no more dispensable. Accordingly, it is possible to enhance the operability and, at the same time, it is possible to acquire the large-sized (large-screen) display device with the high definition.
According to the present invention, it is possible to ensure the maintenance of the hermetic property between the support body members as well as between the support body and both substrates whereby it is possible to acquire the large-sized (large-screen) display device with the high definition.
According to the present invention, the support body members are preliminarily hermetically bonded to each other using the bonding material thus forming the support body and, thereafter, the support body is hermetically sealed with both substrates using the sealing material. Accordingly, even when a temperature of the support body is elevated to the desired high temperature during steps after sealing, the hermetic bonding between the support body members can be ensured whereby it is possible to acquire the large-sized (large-screen) display device with the high definition.
According to the present invention, the displacement between the support body members is hardly generated at the time of performing the sealing, the evacuation and the like and hence, the hermetic property can be ensured whereby the use of the above-mentioned jig is no more dispensable. Accordingly, it is possible to enhance the operability and, at the same time, it is possible to acquire the large-sized (large-screen) display device with the high definition.
According to the present invention, it is possible to ensure the maintenance of hermetic property between the support body members as well as between the support body and both substrates and hence, it is possible to acquire the large-sized (large-screen) display device with the high definition.
An image display device according to the present invention is characterized in that a support body which is interposed between both substrates and surrounds a display region is constituted of a mass of a plurality of support body members and, at the same time, a bonding material which hermetically bonds the support body members and a sealing material have properties different from each other.
To describe typical constitutions of the image display device according to the present invention, they are as follows.
In the image display device which includes a face substrate which forms an anode and a phosphor on an inner surface thereof, a back substrate which forms a plurality of electron sources on an inner surface thereof and faces the face substrate with a given distance therebetween, and a support body which is interposed in a state that the support body surrounds the display region between the face substrate and the back substrate and holds the given distance, and in which end surfaces of the support body and the face substrate and the back substrate are hermetically sealed respectively using a sealing material, the improvement is characterized in that the support body is constituted of a plurality of support body members, and the support body members are hermetically bonded to each other using a bonding material.
Further, in the image display device according to the present invention, the bonding material is configured to have a softening point higher than a softening point of the sealing material and the softening point difference is set to 30° C. or more.
Still further, the bonding material and the sealing material are made of frit glass.
Further, in a manufacturing method of an image display device according to the present invention which manufactures an image display device which includes a face substrate which forms an anode and a phosphor on an inner surface thereof, a back substrate which forms a plurality of electron sources on an inner surface thereof and faces the face substrate with a given distance therebetween, and a support body which is interposed in a state that the support body surrounds the display region between the face substrate and the back substrate and holds the given distance, and in which end surfaces of the support body and the face substrate and the back substrate are hermetically sealed respectively using a sealing material, the improvement is characterized in that the support body is constituted of a plurality of support body members, the support body members are hermetically bonded to each other using a bonding material and, thereafter, the face substrate and the back substrate are respectively hermetically sealed using a sealing material.
Further, in the manufacturing method of an image display device according to the present invention, the bonding material is configured to have a softening point higher than a softening point of the sealing material and the softening point difference is set to 30° C. or more.
Still further, the bonding material and the sealing material are made of frit glass.
Due to the above-mentioned constitution, it is possible to realize the image display device which can exhibit the excellent hermetic property holding function, can perform the high quality display, and still can make the screen large-sized.
Here, it is needless to say that the present invention is not limited to the above-mentioned constitution and the constitution of embodiments described later and various modifications can be made without departing from the technical concept of the present invention.
[Embodiment 1]
Hereinafter, the embodiments of the present invention are explained in detail in conjunction with drawings.
Here, although the explanation is made with respect to a case in which the present invention is applied to an FED (field emission type display device), the present invention is applicable to other similar display device and other similar equipment.
In this image display device, the back substrate 1 and the face substrate 2 are formed of a glass plate and the support body 13 is made of a glass material. Here, various constitutional components such as electron sources, phosphor layers and the like which are formed on respective inner surfaces of the back substrate land the face substrate 2 are omitted from the drawing.
In
The support body 13 includes two long-side support body members 13X1 and 13X2, two short-side support body members 13Y1 and 13Y2, and four corner support body members 13C1, 13C2, 13C3, 13C4, wherein these support body members are assembled into a shape and a size which allow them to surround the display region. Further, the support body members are hermetically bonded to each other at respective bonding surfaces 13P using a bonding material 14 such as frit glass. Further, in the above-mentioned constitution, the respective bonding surfaces 13P are formed in an oblique shape.
Here, with respect to the support body 13 which is an assembled body constituted of the support body members, it is desirable that a height of the support body 13 in the z direction is uniform over the whole surface of the whole circumference thereof. When the support body is configured to include a large stepped portion, the leaking of liquid crystal may arise.
Further, the bonding material 14 is made of frit glass which has properties different from properties of the sealing material 4.
That is, as an example of the bonding material 14,
amorphous frit glass having a softening point of 440° C., for example, and a bonding temperature of 480° C. is used, while as the sealing material 4, amorphous frit glass having a softening point of 390° C. which is 50° C. lower than the softening point of the bonding material 14 and a sealing temperature of 430° C. is used.
Further, as another examples, the bonding material and the sealing material having following properties in Table 1 can be used.
Although these frit glasses may have various compositions, for example, amorphous frit glass essentially consisting of PbO: 70 wt %, B2O3:4 wt %, TiO2:9 wt % and the balance can be used. The control of the softening point of the frit glass can be performed by changing a quantity of oxide content. For example, when a quantity of oxide having a low melting point is large, the softening point becomes low, while when a quantity of oxide having a high melting point is large, the softening point becomes high.
Further, the technique to control the softening point by changing the composition ratio of the constituent contents of the frit glass is already disclosed in a handbook on glass or the like.
Due to the constitution of this embodiment, it is possible to easily form the support body members and the support body. Further, by forming the bonding surface defined between the support body members into an oblique shape, it is possible to ensure a large bonding area and, at the same time, the flowing out of the bonding material along the bonding surface can be prevented thus ensuring the reliability of the hermetic bonding.
Here, although the bonding material which exhibits the softening point difference of 50° C. with respect to the sealing material is used in this embodiment, even when the difference is small, the bonding material can be practically used so long as the softening point difference is at least 30° C. It is desirable that the softening point difference is 50° or more from a viewpoint of tolerance of bonding operation.
[Embodiment 2]
In
Each overlapped portion 23C includes a recessed portion 23H which is shown in
The recessed portion 23H shown in
The bonding material 14 is applied to an inner side wall 23H and a bottom surface 23H2 of the recessed portion 23H and the support body member 23X1 and another support body member are hermetically bonded to each other using this bonding material 14.
The reason why this constitution is adopted is as follows. The shape of the overlapped portion is formed of the recessed portion having the approximately square shape with the opening on a top surface. Accordingly, the shape of the overlapped portion is simple and hence can be easily formed. Further, since the two-dimensional bonding can be achieved, the hermetic adhesion and fixing between the support body members can be ensured.
Further, since the support body members are fixed to each other two-dimensionally on the overlapped surface, at the time of sealing the support body and both substrates, in a portion or the whole of the evacuating step and the like, it is possible to ensure the desired hermetic property holding function even when a jig for holding the support body is not used.
[Embodiment 3]
In
Each overlapped portion 33C includes a bonding portion 33H which is shown in
The bonding portion 33H shown in
By applying the bonding material 14 to the first thin wall portion 33X13, the second thin wall portion 33X14, the first wall portion 33X15 and the second wall portions 33X16, 33X17 of the bonding portion 33H and, thereafter, the support body member 33X1 and other support body member are hermetically bonded to each other using the bonding material 14.
Due to such a constitution, the overlapped portions per se can be easily formed and, at the same time, due to the provision of the stepped portions (wall portions), it is possible to ensure the wide bonding area whereby the hermetic property holding function can be enhanced.
Further, since the support body members are fixed to each other two-dimensionally on the overlapped surface, at the time of sealing the support body and both substrates, in a portion or the whole evacuating step and the like, it is possible to ensure the desired hermetic property holding function even when a jig for holding the support body is not used. [Embodiment 4]
Next, the manufacturing method of the display device of the present invention is explained.
In
Next, to the face substrate 2 on which the phosphor surface is formed, a sealing material 4 which is formed by mixing amorphous frit glass and a given binder and a fixing material 7a for fixing the spacers 7 which is formed by mixing frit glass and a given binder, for example, are applied in given patterns thus forming a face substrate preliminarily assembled body FTA.
Here, it is possible to form all sealing material 4 on the support body 13 side without forming the sealing material 4 on the substrate.
This face substrate preliminarily assembled body FTA is preliminarily baked (P-a) at a temperature of approximately 150° C. which dissipates the binder and, thereafter, the fixing material 7a and the spacers 7 are positioned using jigs (not shown in the drawing) or the like. Then, the face substrate preliminarily assembled body FTA is heated at a temperature of, for example, 450° C. in the atmosphere for 10 minutes so as to fix one end surfaces of the spacers 7 to the face substrate 2 using the fixing material 7a thus forming a face substrate assembled body FPA.
On the other hand, on the back substrate 1 side, first of all, a plurality of cathode lines CL which extend in one direction, for example, in the x direction and are arranged in parallel in another direction which intersects one direction, for example, in the y direction, control electrodes GL and the like are formed. Thereafter, the above-mentioned fixing material 7a and the sealing material 4 in which given binders are respectively mixed are applied and formed on the back substrate 1 side thus forming a back substrate preliminarily assembled body BTA.
Here, the fixing material 7a may differ in properties between the fixing material 7a used on the back substrate 1 side and the face substrate 2 side.
This back substrate preliminarily assembled body BTA is preliminarily (P-b) baked at a temperature of approximately 150° C. which dissipates the binder and, thereafter, the electron sources 5 are formed on the cathode lines CL thus forming a back substrate assembled body BPA.
On the other hand, the support body 13 is formed in a separate step described hereinafter.
That is, the respective support body members 13X1, 13X2, 13Y1, 13Y2, 13C1 to 13C4 are set in the inside of the jig in a given arrangement in a state that the bonding material 14 which is formed of a paste produced by mixing amorphous frit glass having properties of, for example, a softening point of 440° C. and a bonding temperature of 480° C. and a given binder is interposed between each bonding surface 13P of the respective support body members thus forming the support body preliminarily assembled body STA. Then, the support body preliminarily assembled body STA is heated at the bonding temperature of 480° C. for 10 minutes under pressure thus forming the support body 13.
To both upper and lower end surfaces of the support body 13, that is, to the above-mentioned top surface TH and the lower end surface UH, the sealing material 4 which is formed of a paste produced by mixing amorphous frit glass having properties of, for example, a softening point of 390° C. and a sealing temperature of 430° C. and a given binder is applied thus forming the support body preliminarily assembled body STA. Then, the support body 13 is preliminarily heated at a temperature of approximately 150° C. which is a temperature sufficient to dissipate the binder thus forming the support body assembled body SPA.
Next, three assembled bodies constituted of the face substrate assembled body FPA which fixes one end surfaces of the spacers 7 to the face substrate 2, the back substrate assembled body BPA and the support body assembled body SPA are overlapped in the z direction thus forming a panel preliminarily assembled body PSA. In a state that the panel preliminarily assembled body PSA is pressurized in the z direction, the panel preliminarily assembled body PSA is heated (P-e) at a temperature lower than the softening point of the bonding material 14, for example, 430° C. for 10 minutes thus hermetically sealing (P-f) both substrates 1, 2 and the support body 13 using the sealing material 4. Another end surfaces of the spacers 7 are fixed to the back substrate 2 using the fixing material along with this hermetic sealing.
Next, the exhaust baking (P-g) is performed to evacuate the space which is surrounded by both substrates 1, 2 and the support body 13 and constitutes the display region using an exhaust pipe not shown in the drawing. This exhaust baking is a step in which the panel preliminarily assembled body PSA is arranged in a vacuum furnace and is baked at a maximum temperature lower than the softening point of the bonding material, for example, 380° C. for several hours.
Further, in a mode which has no exhaust pipe, the above-mentioned exhaust baking can be performed simultaneously with the hermetic sealing.
Thereafter, in the constitution having the exhaust pipe, the exhaust pipe is tipped off after completion of the evacuation and the panel assembled body PA is manufactured through given treatment such as aging (P-h).
According to the above-mentioned manufacturing method, the treatment is performed at the temperature lower than the softening point of the bonding material 14 in the hermetic sealing using the sealing material 4 and the succeeding heating step and hence, the melting and the softening of the bonding material 14 which hermetically bonds the support body members each other do not occur whereby the support body members are firmly hermetically bonded with each other thus obviating the occurrence of the displacement and the leaking. Accordingly, the support body can sufficiently exhibit its function as the support body.
Number | Date | Country | Kind |
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2004-032213 | Feb 2004 | JP | national |