JP2001351519A - Paste coating device - Google Patents

Abstract

(57) Abstract: Provided is an apparatus for applying paste between ribs by an electric field jet method, which provides a paste application apparatus having an application head having a horizontally long ejection hole. SOLUTION: In a paste coating apparatus using a coating head having a plurality of discharge holes, and filling the phosphor paste between ribs of the substrate while moving the coating head relatively to the substrate, Two members, one member 12 having a plurality of recesses 12a formed in the contact surface and the other member 13 having a flat contact surface, are provided at the tip of the manifold in the coating head, and these two members are combined. A nozzle portion having a plurality of horizontally elongated discharge holes h is formed. Even if it is necessary to form the nozzle portion of the coating head with an insulating material such as ceramic, since the concave portion 12a can be formed by cutting, a horizontally long shape which can be applied evenly while touching the ribs on both sides. And a coating head having the discharge holes h.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of forming a phosphor screen of a plasma display panel (hereinafter, referred to as a PDP) which is a self-luminous type flat panel display utilizing gas discharge.

[0002]

2. Description of the Related Art In general, a PDP has a structure in which a pair of electrodes arranged regularly on two opposing glass substrates are provided, and a gas mainly composed of Ne, Xe or the like is sealed between the electrodes. Then, a voltage is applied between these electrodes,
By generating a discharge in a minute cell around the electrode, each cell emits light to perform display. In order to display information, regularly arranged cells are selectively caused to emit light. There are two types of PDPs, a direct current type (DC type) in which the electrodes are exposed to the discharge space, and an alternating current type (AC type) in which the electrodes are covered with an insulating layer. And a refresh driving method and a memory driving method.

FIG. 1 shows a configuration example of an AC type PDP. This figure shows the front plate and the back plate separated from each other. As shown in the figure, two glass substrates 1 and 2 are arranged in parallel and opposed to each other, and both become the back plate. The stripe-shaped ribs 3 provided on the glass substrate 2 in parallel with each other are held at regular intervals. Sustain electrodes 4 are provided on the back side of glass substrate 1 serving as a front plate.
Are formed in parallel with each other, and a dielectric layer 6 is formed so as to cover the composite electrode, and a protective layer 7 is further formed thereon.
(MgO layer) is formed. On the front side of the glass substrate 2 serving as the back plate, address electrodes 8 are formed between the ribs 3 so as to be orthogonal to the composite electrodes and are formed in parallel with each other. 9 are formed, and a phosphor layer 10 is provided so as to cover the wall surface of the rib 3 and the cell bottom surface. The AC type PDP is of a surface discharge type, and has a structure in which an AC voltage is applied between composite electrodes on a front panel to discharge by an electric field leaking into a space. In this case, since the alternating current is applied, the direction of the electric field changes according to the frequency. Then, the phosphor layer 10 emits light by the ultraviolet light generated by the discharge, so that an observer can visually recognize the light transmitted through the front plate.

In the back plate of the above PDP, an address electrode 8 is formed on a glass substrate 2, a dielectric layer 9 is formed so as to cover the address electrode 8 if necessary, and then a rib 3 is formed. It is manufactured by providing the phosphor layer 10 between the ribs 3. As a method for forming the electrode 8, a method of forming a film of an electrode material on the glass substrate 2 by a vacuum evaporation method, a sputtering method, a plating method, a thick film method, and the like, and patterning the film by a photolithography method; There is known a method of patterning by a screen printing method using a method. The dielectric layer 9 is formed by screen printing or the like. The ribs 3 are patterned by screen printing or by sandblasting.

The phosphor layer 10 is selectively filled with phosphor paste for each color of red (R), green (G), and blue (B) between the ribs 3, and then dried and fired. Conventionally, screen printing is employed for filling the phosphor paste. That is, the process of selectively filling the phosphor paste between the ribs by screen printing and drying is repeated three times, and thereafter, firing is performed. However, it is necessary to use a screen plate corresponding to the high definition and large area of the PDP. However, such a screen plate is stretched or distorted. Difficult to match,
There was a problem that the phosphor paste could not be filled accurately.

Therefore, recently, a coating head having a plurality of discharge holes in a direction perpendicular to the coating direction has been used, and the phosphor paste is filled between the ribs while moving the coating head relatively to the substrate. A coating method has been proposed. FIG. 2 is a schematic view of a method for simultaneously applying three colors of the phosphor paste, which is performed using a coating apparatus incorporating the coating head.

In FIG. 2, G is a substrate on which ribs 3 are formed, and a coating apparatus having a plurality of coating heads H is moved relative to the substrate G to transfer the phosphor paste between the ribs. It is configured to be filled once. That is, the four coating heads Hr intended to eject the fluorescent paste of red, two for the front and rear extending over the first sub-frames F ₁ in the main frame Fm is attached alternately, each coating head Hr Discharge holes in the substrate G
In the width direction. Similarly, four coating heads Hg intended to discharge the phosphor paste for green, two on the front and rear straddles the second sub-frame F ₂ in the main frame Fm is attached alternately, each coating head H
The plurality of ejection holes at g are continuous in the width direction of the substrate. Similarly, the four coating heads Hb discharge the blue phosphor paste, and the main frame F
two on the front and rear extending over the third sub-frame F ₃ to m are mounted alternately, a plurality of discharge holes in each coating head Hb is adapted to continuously in the width direction of the substrate. Accordingly, the respective coating heads H are integrally moved relative to the substrate while discharging the phosphor paste from the plurality of discharge holes, so that the phosphor paste of three colors can be interposed between predetermined ribs in a single coating process. Is filled.

FIG. 3 is an explanatory diagram of a method of applying a phosphor paste using a coating head. As shown in the figure, the phosphor paste P is put into a paste tank T in advance. The phosphor paste P is supplied to the coating head H by applying pressure to the paste tank T by air, and the coating head H also applies a constant pressure to the inside of the manifold by air so that the paste is discharged from the discharge hole at the tip. The phosphor paste P is discharged. Therefore, the phosphor paste P is discharged from the discharge holes of the coating head H while the substrate G and the coating head H are relatively moved at a predetermined interval, so that the predetermined gap can be filled between the ribs 3.

As described above, the phosphor paste can be filled between the ribs by using the coating head. In this method, as shown in FIG.
When a high-voltage pulse from the high-voltage pulse generator A is applied between the substrate and the substrate G to generate an electric field, and the phosphor paste P is discharged in this state, the phosphor paste P
Has been empirically found to be able to be filled smoothly. In order to apply a high-voltage pulse, it is necessary to attach an electrode to the coating head H. FIG. 4 shows an example of attaching an electrode to the coating head. In this example, a pair of electrodes E is attached to the outside of the tip of the nozzle portion N. As another example, it may be attached inside the coating head H. The high-voltage pulse output from the high-voltage pulse generator A is as shown in FIG.
The pulse width b is set to about 3 to 10 kV.

According to the method of filling the phosphor paste between the ribs with the application head in the state where the electric field is applied (hereinafter referred to as the electric field jet method), as shown in FIG. The body paste P can be smoothly filled. The figure shows the state of filling as viewed from the front in the traveling direction. After the simultaneous application of the three colors, as shown in FIG. 7A, the phosphor paste Pr for red and the phosphor paste P for green are respectively provided between predetermined ribs 3.
g, a state where the phosphor paste Pb for blue color is filled. After the drying step, the phosphor paste is depressed as shown in FIG. After this drying step, a phosphor screen is formed through a baking step.

[0011]

In the case of applying the line by the electric field jet method as described above, if the phosphor paste is applied while touching only one rib, unevenness occurs due to a difference between right and left. In order to suppress this unevenness, it is necessary to apply the paste while touching the ribs on both sides. However, as shown in FIG. 8, when the paste P is discharged from the circular discharge hole h on the nozzle bottom surface B, Since the discharge cross-section is considered to be substantially circular, if the diameter of this circle is smaller than the interval between the ribs 3, the paste P cannot contact the ribs 3 on both sides. In order to make this possible while keeping the discharge amount constant, the shape of the paste P to be discharged needs to be horizontally long as shown in FIG. That is,
It is necessary to make the shape of the ejection hole h of the coating head horizontally long. However, since the coating head used in the electric field jet method is made of an insulating material such as glass ceramic, it is very difficult to form a horizontally long hole in the coating head by electric discharge machining or the like.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an apparatus for applying a phosphor paste between ribs by an electric field jet method. An object of the present invention is to provide a paste application device having a head.

[0013]

In order to achieve the above object, the present invention uses a coating head having a plurality of discharge holes in a direction perpendicular to the coating direction, and the coating head is opposed to a substrate so as to face the substrate. In a paste application apparatus for forming a phosphor screen of a PDP in which a phosphor paste is filled between ribs of a substrate while being moved, one member having a plurality of recesses formed in a contact surface and a contact surface Is provided at the tip of the manifold in the coating head, the other member being flat, and by combining these two members, a nozzle portion having a plurality of horizontally elongated discharge holes is formed. I do.

[0014]

Preferred embodiments of the present invention will be described below with reference to the drawings.

FIGS. 10 and 11 show an example of the coating head in the coating apparatus according to the present invention. FIG. 10 is a front view of the coating head viewed from the front end side, and FIG. 11 is a side view of the coating head.

As shown in the drawing, the coating head has a nozzle portion formed of two members 12 and 13 at the tip of a manifold 11. These two members 12, 13 are shown in FIG.
The one member 12 has a plurality of recesses 12a formed in the contact surface, and the other member 13 has a flat contact surface. Then, by combining the two members 12, 13, a plurality of horizontally long ejection holes h are formed as shown in FIG. One member 12
In this case, a groove-shaped concave portion 12a is formed. However, such a cutting process can be performed relatively easily even with an insulator such as a ceramic.

Here, as shown in FIG. 14, the height of the rib to which the phosphor paste is to be applied is H, the opening width of the rib top is L, the width of one discharge hole h is α, and the length is α. To β
Then, it is desirable that L / H ≧ β / α. Specifically, the length α is preferably set to about 1.5 to 4 times the opening width L of the top of the rib on which the phosphor paste is to be applied, and the width β is preferably set to about 0.7 times.

When the two members 12 and 13 are integrated, as shown in FIGS. 10 and 11, they are clamped by a pair of clamp jigs 14 whose center is expanded.
That is, the two members 12 and 13 are sandwiched between the clamp jigs 14 and both ends are fastened with the screws 15 and then attached to the manifold 11. At this time, manifolds 11 and 2
The surface accuracy of the mating surface with the two members 12 and 13 is improved, and a gap is eliminated by inserting an O-ring therebetween.

The clamp jig 14 has a shape in which the center is bulged, but a shape bulged in a curved shape as shown in FIG. In this case, it is important not to open all the discharge holes h over the entire length, and for that purpose, it is preferable to adopt a catenary line shape rather than an arc.

[0020]

As described above, in the paste coating apparatus of the present invention, the nozzle portion of the coating head is constituted by two members, that is, a plurality of recesses are formed on the contact surface of one member. Then, a plurality of horizontally long discharge holes are formed by matching with the smooth contact surface of the other member, so that the nozzle portion of the coating head is applied as in the case where the phosphor paste is line-coated by the electric field jet method. Even if it is necessary to form the recesses with an insulator such as ceramic, since the recesses can be formed by cutting, coating with a horizontally long discharge hole that can be applied evenly while touching the ribs on both sides A head can be provided.

[Brief description of the drawings]

FIG. 1 is a structural diagram showing an example of a configuration of an AC type plasma display panel in a state where a front plate and a back plate are separated from each other.

FIG. 2 is a schematic view of a method for simultaneously applying three colors of a phosphor paste, which is performed using a coating apparatus incorporating a coating head.

FIG. 3 is an explanatory diagram of a method of applying a phosphor paste using an application head.

FIG. 4 is a cross-sectional view showing an example of attaching electrodes to a coating head.

FIG. 5 is a waveform diagram of a high-voltage pulse applied between a coating head and a substrate.

FIG. 6 is an explanatory view showing a state in which a phosphor paste is filled between ribs.

FIG. 7 is an explanatory diagram showing a state in which phosphor pastes of three colors are filled and a state after a drying step.

FIG. 8 is an explanatory diagram for explaining a shape of a discharge hole in a coating head and a state of coating between ribs.

FIG. 9 is an explanatory diagram for explaining a shape of a discharge hole in a coating head and a state of coating between ribs.

FIG. 10 is a front view of an example of a coating head in the coating apparatus according to the present invention, as viewed from the tip side.

FIG. 11 is a side view of the coating head.

12 (A) is a front view showing two members constituting the coating head in a separated state, and FIG. 12 (B) is FIG.
It is AA sectional drawing of (A).

FIG. 13 is a partially enlarged view showing a discharge hole formed by two members.

FIG. 14 is an explanatory diagram showing the size of a discharge hole.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front plate 2 Back plate 3 Rib 4 Sustain electrode 5 Bus electrode 6 Dielectric layer 7 Protective layer (MgO layer) 8 Address electrode 9 Dielectric layer 10 Phosphor layer 11 Manifold 12 One member 12a Depression 13 The other member 14 Clamp Jig 15 Screw h Discharge hole P Phosphor paste

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tatsuru Tashiro 1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd. F-term (reference) 4F033 AA14 DA05 4F034 AA04 BA04 4F041 AA02 AA05 AB02 BA05 BA13 BA17 5C028 FF16 5C040 FA01 GG09 JA13 MA23 MA24

Claims (2)

[Claims] 1. A plasma display panel comprising: a coating head having a plurality of discharge holes; and filling the phosphor paste between ribs of the substrate while moving the coating head relatively to the substrate. In a paste application device for forming a phosphor screen, one member having a plurality of recesses formed on a contact surface and the other member having a flat contact surface are used.
A paste coating apparatus, wherein two members are provided at a tip of a manifold in the coating head, and a nozzle portion having a plurality of horizontally elongated discharge holes is formed by combining these two members. 2. The paste application device according to claim 1, wherein one member forming the nozzle portion and the other member are fastened by a clamp jig.