JP3373416B2 - Method for forming dielectric layer of plasma display panel - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a dielectric layer of an AC type plasma display panel having a dielectric layer for accumulating charges on a discharge electrode.

Plasma display panel (PDP)
Has attracted attention as a display device capable of achieving a large screen, and there is a trend toward higher definition and higher brightness in order to improve display quality. The dielectric layer is a component that greatly affects the discharge characteristics in the AC type PDP, and it is necessary to accurately form the dielectric layer in order to improve the display quality.

[0003]

2. Description of the Related Art First, the basic structure of a PDP will be described. FIG. 3 shows an AC type PDP having a three-electrode structure for surface discharge.
It is a cross-sectional view showing the structure of.

The PDP is formed by laminating a pair of substrates (front side and back side) that have been subjected to various treatments so as to have a discharge space, and the front substrate 21 is a surface for display. A display electrode (also referred to as a sustain electrode) 22 for generating a discharge is provided, and a dielectric layer 23 is formed so as to cover the display electrode 22. A protective film 24 made of magnesium oxide or the like is deposited on the surface of the dielectric layer 23.

On the other hand, as shown in FIG. 3, the rear substrate 25 has a plurality of address electrodes 26 for generating address discharge for display, and a dielectric layer 27 is formed so as to cover the address electrodes 26. In addition, a plurality of barrier ribs 28 that define a discharge region and define a discharge gap are formed on the dielectric layer 27.
Are formed, and phosphors 29 for color display are applied between the partition walls 28.

In the following, a conventional PD is taken by taking the process of the front substrate as an example.
A method of forming P will be described. FIG. 4 is a process diagram of forming a dielectric layer according to the related art, and is a sectional view taken from a direction different from that of FIG.

First, a display electrode 32 for generating a surface discharge is formed on a glass substrate (front substrate) 31 using a photolithography technique, and then a dielectric paste 33 is screen-printed as shown in FIG. 4 (A). Apply by.

The dielectric paste 33 is composed of glass particles 34 made of a dielectric material and a liquid substance 35 for making a paste. The glass particles 34 are made by crushing the dielectric material by a ball mill. It is a thing. In addition, the liquid substance 35 contains a binder for binding the glass particles 34 and a solvent for adjusting the viscosity.

After the dielectric paste 33 is applied, a drying process is performed to evaporate the solvent to obtain the state shown in FIG. 4 (B). In this state, the glass particles 34 are bound by the binder 36.

[0010] Thereafter, performs predetermined time firing at about 500 ° C., was removed by burning binder 36, Gala
Scan particles 34 to obtain a dielectric layer 37 aligned in the stone wall structure form. The firing temperature at this time is set to a temperature at which the glass particles 34 are not melted in order to avoid affecting the display electrode 32.

The glass particles 34 that have been used conventionally are formed by crushing by a ball mill for a predetermined time, and the particle size is set to some extent depending on the crushing time, but there are inevitably variations. Therefore, the glass particles 34 include particles that are not sufficiently crushed and have a large particle size.

When the large-diameter glass particles 34 are contained as described above, as shown in FIG. 4 (C), the projections 38 are locally formed, and voids 39 and pinholes which become internal spaces are formed. 40 will be generated.

[0013]

The film thickness of the finally obtained dielectric layer 37 is determined by the amount of the glass particles 34 existing per unit area, and is larger than this film thickness. When the glass particles 34 having the particle diameter are present, the protrusions 38 are naturally formed on the portions, which deteriorates the flatness of the surface.

Further, the glass particles 34 are polyhedrons, and if the particle size is large, one surface of the glass particles 34 becomes large, so that they are adjacent to each other.
Voids 39 and pinholes 40 are easily generated between the glass particles, and the dielectric layer 37 lacks the denseness. In particular, the void 39 is likely to occur in the step portion between the display electrode 32 and the substrate.

When the protrusions 38, the voids 39, and the pinholes 40 as described above are generated, the electric field strength is locally reduced to induce abnormal discharge, and the characteristics for obtaining good display quality are obtained. I can't.

In particular, it has become difficult to satisfy the demands for display quality accompanying the recent trend toward higher definition and higher brightness. The present invention solves the above problems and provides a dielectric layer forming method of a PDP capable of forming a dielectric layer in a high-definition and high-luminance large-screen PDP with high accuracy, thereby improving display quality. It is an object.

[0017]

The present invention for solving the above problems provides a method for forming a dielectric layer of a plasma display panel, which comprises coating a display electrode provided on a substrate with a dielectric layer. On the substrate provided with electrodes for use , a plurality of substantially spherical and uniform dielectrics having a diameter smaller than the film thickness of the dielectric layer concerned.
The dielectric paste formed of the body of glass particles and liquid substances, the steps of applying to cover the display electrode, with to burn a liquid substance contained in the prior SL dielectric paste, the
Depending on the temperature that melts only the surface of each glass particle,
By the step of firing the dielectric paste ,
Glass grains is of Turkey to form a dielectric layer secured in alignment with hierarchical. Thus, according to the present invention,
Since only the small diameter glass particles are contained in the dielectric paste, the surface of the dielectric layer after firing becomes flat and one surface of each glass particle becomes smaller, so that the occurrence of voids and pinholes can be suppressed. You can Therefore, abnormal discharge due to a local decrease in electric field strength can be prevented, and good display characteristics can be obtained.

[0018]

[0019]

Further, in the method for forming a dielectric layer of a PDP according to the present invention, the dielectric paste contains a light-reflecting white filler having a diameter smaller than the thickness of the dielectric layer, if necessary. According to the present invention as described above, it is possible to apply the present invention to a back-side substrate that requires prevention of reflected light.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment of the Present Invention) A first embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a process diagram of forming a dielectric layer according to the first embodiment, which is an example of a front side substrate of an AC type PDP having a three-electrode structure.

First, the display electrode 2 is formed on the front glass substrate 1 by the photolithography technique. The display electrode 2 forms a narrow bus electrode on a part of a wide transparent electrode, and generates a surface discharge by applying a voltage to a pair of (X, Y) electrodes. .

After that, the dielectric paste 3 is applied by screen printing on the glass substrate 1 so as to cover the display electrodes 2. As shown in FIG. 1A, the dielectric paste 3
Is composed of glass particles 4 as a dielectric material and a liquid substance 5.

As the glass particles 4, only those having a diameter smaller than the film pressure of the dielectric layer to be formed are obtained by crushing the dielectric glass by a ball mill for a predetermined time and separating the crushed glass by centrifuging. It was selected.

The liquid substance 5 contains a binder for binding the glass particles 4 and a solvent for adjusting the viscosity of the paste. By kneading the paste with a general kneader, the glass particles 4 can be made uniform. It exists in the state.

After applying such a dielectric paste 3, the dielectric paste 3 is dried.
The solvent contained in is evaporated to obtain the state shown in FIG. 1 (B) in which the glass particles 4 are bound by the binder 6.

Then, the binder 6 is removed by burning it by a firing treatment to obtain a dielectric layer 7 as shown in FIG. 1 (C). In this embodiment, since it is necessary to transmit visible light (light emission of the phosphor), the dielectric layer 7 is the glass substrate 1
It is as transparent as.

In the firing process, the binder 6 is burned 3
The first heat treatment is performed at about 50 ° C., and the second heat treatment is performed at about 500 ° C. for fixing the glass particles to each other by melting only the surface portions of the glass particles 4. The firing temperature is set to a temperature at which the dielectric material does not melt and fuse with the display electrode 2.

The glass particles 4 having a small diameter are polyhedrons having corners when viewed microscopically, but each surface is small and macroscopically almost spherical. In addition, since the particle size is selected by the centrifuge, the surface on which the glass particles are arranged hierarchically is flat (surface roughness is 1 μm, as shown in FIG. 1C).
The following) can form a dense dielectric layer having a stone wall structure . Therefore, it is possible to suppress the generation of local protrusions, voids, and pinholes, and it is possible to form the dielectric layer 7 with high accuracy.

The amount of the glass particles 4 per unit area is set so that the dielectric layer 7 has a thickness of about 10 μm.
The particle size of the glass particles 4 contained in the dielectric paste 3 is
It is 4 to 6 μm.

Thereafter, although not shown, a protective film made of magnesium oxide is formed on the dielectric layer 7 by vapor deposition to complete the front substrate. This front substrate is bonded to a separately formed rear substrate through the discharge space to complete a PDP as shown in FIG.

(Second Embodiment of the Present Invention) In the first embodiment, the formation of the dielectric layer on the front substrate was described, but the rear substrate also has the same structure having the dielectric layer on the electrodes. Therefore, the present invention can be applied.

As shown in FIG. 3, the rear glass substrate 25
Address electrodes 2 for generating an address discharge are formed on the upper side.
6, a dielectric layer 27 is formed so as to cover the address electrode 26, a partition 28 for defining a discharge region, and a phosphor 29 are sequentially formed. The phosphor 29 generates visible light due to the ultraviolet rays generated by the discharge, and this becomes an image when it is seen from the front side substrate.

It is necessary to secure the brightness of the display by making the dielectric layer 27 on the back side have a structure that reflects the light transmitted through the phosphor layer 29. Therefore, the dielectric layer 27 on the back side contains a light-reflecting white filler. This example will be described below.

FIG. 2 is a process diagram of forming a dielectric layer according to the second embodiment. First, the address electrodes 12 are formed on the glass substrate 11 on the back side by a photolithography technique. The address electrode 12 generates an address discharge between itself and the display electrode by applying a voltage.

After that, a dielectric paste 13 is applied by screen printing on the glass substrate 11 so as to cover the address electrodes 12. As shown in FIG. 2A, the dielectric paste 13 is composed of glass particles 14 as a dielectric material, a white filler 15 and a liquid substance 16.

The glass particles 14 are obtained by crushing the dielectric glass in a ball mill for a predetermined time, separating the crushed glass by centrifuging, and selecting only those having a small diameter. Further, as the white filler 15, the white colored insulating material is also crushed by a ball mill and separated by applying a centrifugal separator, and only a small diameter is selected.

Further, the liquid substance 16 contains a binder for binding the glass particles 14 and the white filler 15 and a solvent for adjusting the viscosity of the paste, and by kneading with a general kneader, the liquid substance 16 The particles 14 and the white filler 15 are evenly present.

After applying the dielectric paste 13 as described above, the dielectric paste 1 is dried.
The solvent contained in 3 is evaporated to obtain the state of FIG. 2B in which the glass particles 14 and the white filler 15 are bound by the binder 17. Then, the binder 17 is removed by burning it by a firing treatment to obtain a dielectric layer 18 as shown in FIG. In the present embodiment, since the white filler 15 is included, the dielectric layer 18 becomes cloudy as a whole and is in a state of reflecting light.

As in the case of the first embodiment, the firing treatment is the first heat treatment of burning the binder 17 at about 350 ° C., and only the surface portions of the glass particles 14 and the white filler 15 are melted to obtain the glass particles and the white particles. The second heat treatment is performed at about 500 degrees to fix the filler. The firing temperature is set to a temperature at which the dielectric material does not melt and fuse with the address electrode 12.

Small diameter glass particles 14 and white filler 1
Microscopically, 5 is an angled polyhedron, but each surface is small and macroscopically almost spherical. In addition, since the particle size is selected by the centrifuge,
As shown in (C), it is possible to form an evenly aligned stone wall structure.

According to this embodiment, it is possible to obtain a opaque dielectric layer which has no local projections, voids, or pinholes, has excellent display characteristics, and reflects visible light to enhance display brightness. it can. Such a back side substrate is bonded to the front side substrate via the discharge space to complete the PDP as shown in FIG.

As described above, by combining the front side substrate according to the first embodiment and the back side substrate according to the second embodiment, it is possible to obtain a PDP with better display quality. The method for applying the dielectric paste is not limited to screen printing, and a thick film applying method using a roller coater may be used.

[0044]

According to the method for forming a dielectric layer of a plasma display panel of the present invention, since only the selected small-diameter glass particles are contained in the dielectric paste, the dielectric material after firing is Since the surface of the dried film becomes flat and one side of each glass particle becomes short, generation of voids and pinholes can be suppressed.

Therefore, it is possible to prevent abnormal discharge due to local reduction of the electric field strength, and it is possible to obtain good display characteristics.

[Brief description of drawings]

FIG. 1 is a process diagram of forming a dielectric layer according to the first embodiment of the present invention.

FIG. 2 is a process diagram of forming a dielectric layer according to the second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a structure of a plasma display panel.

FIG. 4 is a process diagram of forming a dielectric layer according to a conventional technique.

[Explanation of symbols]

1 Front glass substrate 11 Rear glass substrate 2 Display electrodes 12 address electrodes 3,13 Dielectric paste 4,14 glass particles 15 White filler 5,16 Liquid substance 6,17 binder 7,18 Dielectric layer

Continuation of the front page (56) Reference JP-A-9-50769 (JP, A) JP-A-6-310037 (JP, A) JP-A-8-109015 (JP, A) JP-A-63-49252 (JP , A) JP-A-9-231910 (JP, A) JP-A-6-310036 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01J 9/02

Claims (2)

(57) [Claims] 1. A dielectric layer forming method of the plasma display panel formed by coating the display electrode provided on a substrate with a dielectric layer, on a substrate provided with the display electrode, those
Equal plurality of induction substantially spherical diameter smaller than the thickness of said dielectric layer
Dielectric paste consisting of electric glass particles and liquid substance,
A step of applying to cover the display electrode, with to burn a liquid substance contained in the prior SL dielectric paste, the temperature for dissolving only the surface portions of the respective glass particles
The by a step of firing the dielectric paste, and Turkey to form a dielectric layer secured between the plurality of glass particles are aligned in a hierarchy, a plasma display panel dielectric layer forming method, characterized . 2. The method for forming a dielectric layer of a plasma display panel according to claim 1 , wherein the dielectric paste further contains a light-reflecting white filler having a diameter smaller than a film thickness of the dielectric layer. A method for forming a dielectric layer of a plasma display panel, comprising: