JP2002093321A - Manufacturing method of plasma display panel, and fluorescent ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a PDP enabled to continuously apply the fluorescent ink during long time, and to form an uniform fluorescent layer with good accuracy with ease even when a cell structure is fine, and to provide a fluorescent ink, and a coating device of the ink suitable for the above. SOLUTION: When scanning a nozzle head 53 in X-direction while applying a fluorescent ink, the position of the nozzle head 53 in Y-direction is also controlled in order to make a nozzle 54 follow the scanning line. A mixture of the powder of fluorescent material having an oxide on the surface, which is positively or negatively chargeable in its nature, with average grain diameter of 0.5-5 μm, a mixed solvent, and a binder composed of ethylcellulose with the ethoxy group content of 49% or more in the cellulose molecule, or ethylene oxide group polymer to which, dispersant is added, is used as a fluorescent ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a plasma display panel, and more particularly to an improvement in a phosphor ink and a phosphor coating device used for forming a phosphor layer.

[0002]

2. Description of the Related Art In recent years, expectations for high-definition and large-screen televisions such as high-definition televisions have been increasing.
In the field of displays such as CRTs, liquid crystal displays (LCDs), and plasma display panels (PDPs), the development of displays suitable for them is underway.

Conventionally, CRTs, which have been widely used as television displays, are excellent in resolution and image quality, but have a large screen of 40 inches or more in that the depth and weight increase with the screen size. Is not suitable. In addition, LCDs have excellent performance of low power consumption and low driving voltage, but have technical difficulty in producing a large screen.

On the other hand, a PDP can realize a large screen with a small depth, and a 50-inch class product has already been developed. PDPs are roughly classified into a direct current type (DC type) and an alternating current type (AC type) according to a driving method. At present, an AC type suitable for forming a panel having a fine cell structure is mainly used. ing.

A typical AC surface discharge type PDP as an AC type
In general, a front cover plate on which display electrodes are arranged and a back plate on which address electrodes are arranged are arranged in parallel with a gap therebetween so as to form a matrix, and the gap between both plates is a stripe. It is partitioned by a partition wall. And in the groove between the partitions, red,
A green and blue phosphor layer is formed and a discharge gas is sealed therein. When a voltage is applied to each electrode by a driving circuit to discharge, ultraviolet rays are emitted and phosphor particles of the phosphor layer are emitted. (Red, green, and blue) receive the ultraviolet rays and emit light so that an image is displayed.

In such a PDP, usually, a partition is provided on the back plate side, and a phosphor layer is formed in a groove between the partitions.
It is manufactured by stacking a front cover plate on top of it and filling a discharge gas. By the way, as a method of forming a phosphor layer in a groove between partition walls, JP-A-6-520 discloses
No. 5, as disclosed in Japanese Patent Laid-Open Publication No. 5 (1999), a method in which a phosphor paste is filled in grooves between partition walls and fired (screen printing method).
However, it is difficult to apply the screen printing method to a PDP having a fine cell structure.

For example, at the pixel level of a full-spec high-definition television, the number of pixels is 1920 × 1125, and the pitch (cell pitch) of partition walls in the 42-inch class is used.
Is as small as about 0.1 to 0.15 mm, and the groove width between the partition walls is as narrow as about 0.08 to 0.1 mm. However, since the phosphor ink used for screen printing has a high viscosity, ( Usually, tens of thousands of centipoise), it is difficult to accurately and rapidly flow phosphor ink between such narrow partition walls. It is also difficult to create a screen plate in accordance with a PDP having such a fine structure.

As a method of forming the phosphor layer, a photoresist film method and an ink jet method have been developed in addition to the screen printing method. The photoresist film method, as disclosed in JP-A-6-273925, embeds a film of an ultraviolet-sensitive resin containing a phosphor of each color between barrier ribs to form a phosphor layer of a corresponding color. This is a method in which exposure and development are performed only on a portion to be formed, and a portion that is not exposed is washed away. According to this method, a film can be embedded between partition walls with some accuracy even when the cell pitch is small.

However, since it is necessary to sequentially embed the film, expose and develop and wash away the three colors, there is a problem that the manufacturing process is complicated and color mixing easily occurs, and the phosphor is relatively expensive. In addition, there is a problem that the cost is increased because it is difficult to collect the washed phosphor. On the other hand, the ink jet method
JP-A-53-79371 and JP-A-8-16201
As disclosed in Japanese Patent Application Publication No. 9-209, a method of adhering a phosphor ink in a desired pattern on an insulating substrate by scanning while applying pressure to an ink liquid composed of a phosphor and an organic binder and ejecting the ink from a nozzle. is there. In the ink jet method, ethyl cellulose, acrylic resin or polyvinyl alcohol is used as an organic binder, terpineol or butyl carbitol acetate is used as a solvent,
A phosphor ink manufactured by dispersing a phosphor in a mixture of an organic binder and a solvent using a disperser such as a paint shaker is generally used.

According to such an ink jet method, it is possible to apply the ink to the narrow grooves between the partition walls with high precision, but since the ejected ink adheres intermittently as droplets, It is difficult to apply smoothly along the groove between the partition walls arranged in a stripe shape. In this regard, Japanese Patent Application No. 8-245585 filed earlier by the present inventors etc.
As disclosed in Japanese Patent Application No. Hei 9-253747, the phosphor ink having a low viscosity and good fluidity can be smoothly applied by scanning while continuously jetting from a nozzle while applying pressure. It is.

[0011]

However, even when the phosphor ink is applied by this method, the finished P
When the DP is driven, there is a problem that streak-like unevenness is likely to occur along a partition wall or streak-like unevenness along a break of an address electrode. It is considered that the reason why such streak-like unevenness occurs is that slight variation or color mixture occurs in the phosphor layer formed in each groove. Factors that cause variation include the following.

(1) When the phosphor ink is applied, a charge is generated in the phosphor ink, and the amount of the generated charge is easily affected by the working environment and the working conditions. Is easy to change from place to place. (2) When the phosphor inks of three colors of RGB are applied one by one in order, when applying the phosphor inks of the second color and the third color, the phosphor ink previously applied is applied to the adjacent groove. And the rheological effect of the adjacent phosphor ink, it is difficult to make the adhesion state of the applied phosphor ink constant.

The rheological effect can be eliminated if the next color is applied after sufficiently drying each time one color is applied. However, in this case, the number of drying steps increases, and therefore, the number of drying steps increases. Equipment is required, and the production process becomes complicated. (3) When applying the phosphor ink to the groove between the partition walls, it is preferable to scan the nozzle so that the nozzle is always located at the center of the groove between the partition walls in order to apply the ink uniformly. Even if scanning is performed quickly, if the width of the groove between the partition walls is varied or the groove is curved, a portion where the nozzle is shifted from the center of the groove is generated, so that it is difficult to apply the nozzle uniformly. In particular, in the case of a fine cell structure, a problem easily occurs.

(4) When the phosphor ink having good fluidity is ejected from a fine nozzle, when the ejection from the nozzle is turned on and off, the ejection amount changes and the direction of the jet ejected changes. It is difficult for the phosphor ink to be accurately filled in the partition walls. Further, as another problem, generally, the phosphor ink applied to the groove between the partition walls hardly adheres to the side wall of the partition wall and tends to adhere to the bottom of the groove. It is difficult to form a phosphor layer with good balance. If the side wall of the phosphor layer and the bottom of the groove are not well-balanced, there is a problem that it is difficult to obtain high panel luminance.

Further, since the diameter of the nozzle used in the ink jet method needs to be set to be narrow in accordance with the interval between the partition walls, the nozzle tends to be clogged and it is difficult to apply the phosphor continuously for a long time. There is also. In particular,
When manufacturing a high-definition PDP having a partition wall pitch of 0.15 mm or less, the nozzle diameter needs to be set considerably smaller than this, so that the problem of clogging is likely to occur.

The present invention has been made in view of the above problems, and enables the phosphor ink to be continuously applied over a long period of time. Provided is a method of manufacturing a PDP capable of forming a color filter, and an ink application device and a phosphor ink suitable for the method, whereby the PDP is less likely to have streak unevenness with high image quality and is displayed with high brightness. The purpose is to be able to.

[0017]

Therefore, in the present invention,
In the step of applying the phosphor ink of the PDP, the partition wall is formed while the phosphor ink containing the phosphor particles having the oxide having the property of being positively or negatively charged is discharged from the nozzle in a continuous flow. The coating was performed by relatively scanning the nozzle along the groove between the partition wall.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] [Overall Configuration and Manufacturing Method of PDP] FIG. 1 is a perspective view showing an AC surface discharge type PDP according to an embodiment, and FIG. FIG. 2 is a configuration diagram of a display device on which circuit blocks are mounted.

This PDP has a front panel 10 in which discharge electrodes 12 (scanning electrodes 12a and sustain electrodes 12b), a dielectric layer 13, and a protective layer 14 are arranged on a front glass substrate 11.
And a rear panel 20 in which address electrodes 22 and a dielectric layer 23 are disposed on a rear glass substrate 21.
2b and the address electrodes 22 are arranged in parallel with each other at an interval in a state where they face each other. The gap between the front panel 10 and the rear panel 20 is partitioned by a stripe-shaped partition wall 30 to form a discharge space 40, and a discharge gas is sealed in the discharge space 40.

In the discharge space 40, a phosphor layer 31 is provided on the back panel 20 side. The phosphor layers 31 are repeatedly arranged in the order of red, green, and blue. The discharge electrode 12 and the address electrode 22 are both stripe-shaped. The discharge electrode 12 is arranged in a direction orthogonal to the partition 30, and the address electrode 22 is arranged in parallel with the partition 30.

As shown in FIG. 2, each discharge electrode 12
Are continuously traversed from one end of the panel to the other, but each address electrode 22 is divided at the center of the panel so that it can be driven by a dual scan method. The discharge electrode 12 and the address electrode 22 may be formed of a single metal such as silver, gold, copper, chromium, nickel, and platinum, but the discharge electrode 12 is formed of a conductive metal oxide such as ITO, SnO ₂ , and ZnO. It is preferable to use a combination electrode in which a narrow silver electrode is laminated on a wide transparent electrode made of a material in order to secure a wide discharge area in the cell.

The discharge electrode 12 and the address electrode 22
Have a panel configuration in which cells that emit red, green, and blue light are formed at the intersections. Dielectric layer 13
Is a layer made of a dielectric material disposed over the entire surface of the front glass substrate 11 on which the discharge electrodes 12 are disposed,
In general, lead-based low-melting glass is used, but it may be formed of bismuth-based low-melting glass or a laminate of lead-based low-melting glass and bismuth-based low-melting glass.

The protective layer 14 is made of magnesium oxide (Mg)
O) and covers the entire surface of the dielectric layer 13. The dielectric layer 23 is mixed with TiO ₂ particles so as to also function as a visible light reflecting layer. The partition 30 is made of a glass material, and protrudes from the surface of the dielectric layer 23 of the back panel 20.

(Method of Manufacturing PDP) A method of manufacturing this PDP will be described below. Production of front panel: The front panel is a front glass substrate 11
A discharge electrode 12 is formed thereon, and a lead-based dielectric layer 1 is formed thereon.
3 and then a protective layer 14 is formed on the surface of the dielectric layer 13. The discharge electrode 12 is an electrode made of silver, and is formed by applying a silver paste for an electrode by a screen printing method and firing it. Note that the discharge electrode 12 can be formed by an ink jet method or a photolithography method.

The dielectric layer 13 is made of, for example, 70% by weight of lead oxide [PbO], 15% by weight of boron oxide [B ₂ O ₃ ], 1
0% by weight of silicon oxide [SiO ₂ ] and 5% by weight of aluminum oxide and an organic binder [α-terpineol 1
A solution obtained by dissolving 0% of ethylcellulose], and then applying 520
By baking at 20 ° C. for 20 minutes, a film thickness of about 20 μm is formed.

The protective layer 14 is made of magnesium oxide (Mg).
O) and is generally formed by a sputtering method.
To a film thickness of The formation of the magnesium oxide protective layer by the CVD method is performed by setting a front glass substrate in a CVD apparatus, and feeding and reacting a magnesium compound and oxygen as a source into the front glass substrate. Examples of sources for use herein, magnesium acetylacetone _{[Mg (C 5 H 7 O} 2) 2], cyclopentadienyl magnesium _{[Mg (C 5 H 5)} 2] can be exemplified.

Fabrication of a rear panel: A screen printing method is used on a rear glass substrate
The address electrode 22 is formed. Next, a glass material mixed with TiO ₂ particles is applied by a screen printing method and baked to form the dielectric layer 23.

Next, after repeatedly applying a glass material by a screen printing method, the glass material is baked to form the partition wall 30. Then, the phosphor layer 31 is formed in the groove between the partition walls 30. The method of forming the phosphor layer 31 will be described in detail later. The phosphor ink is applied by a method of scanning along a groove while continuously ejecting the phosphor ink from a nozzle. It is formed by baking to remove the solvent and the binder contained in.

When the material of the partition 30 is selected, the contact angle of the phosphor ink with respect to the side of the partition 30 is selected so that a large amount of the phosphor adheres to the side of the partition when the phosphor ink dries. However, it is preferable to select one that is smaller than the contact angle with respect to the bottom surface of the groove. Also,
In the present embodiment, the height of the partition wall is 0.1 to 0.15 in accordance with a 40-inch class VGA or a high-definition television.
mm, and the pitch of the partition walls is 0.15 to 0.36 mm.

Preparation of PDP by Panel Bonding: Next, the front panel and the rear panel thus prepared are bonded to each other using sealing glass, and the inside of the discharge space 40 partitioned by the partition 30 is subjected to high vacuum ( For example, 8 × 10 ^-7 To
rr), then discharge gas (for example, He-Xe system,
A PDP is manufactured by sealing a Ne—Xe-based inert gas) at a predetermined pressure.

In the present embodiment, the content of Xe in the discharge gas is set to 5% by volume or more, and the filling pressure is 500 to 500%.
Set to the range of 800 Torr. When driving and displaying the PDP, the circuit block is mounted and driven as shown in FIG. [Description of Phosphor Ink, Ink Applicator and Application Method] In the phosphor ink, phosphor particles of each color are dispersed in a mixture of a binder, a solvent, a dispersant, and the like, and are adjusted to an appropriate viscosity.

As the phosphor particles, those generally used for a phosphor layer of a PDP can be used.
Specific examples thereof include a blue phosphor: BaMgAl ₁₀ O ₁₇ : Eu ^{2+ a} green phosphor: BaAl ₁₂ O ₁₉ : Mn or Zn ₂ S.
iO ₄ : Mn Red phosphor: (Y _x Gd _{1 -x} ) BO ₃ : Eu ³⁺ or Y
BO ₃ : Eu ³⁺ can be mentioned.

A detailed description of the composition of the phosphor ink will be described later. FIG. 3 is a schematic configuration diagram of an ink coating device 50 used when forming the phosphor layer 31. FIG.
As shown in the figure, in the ink application device 50, the ink server 51 storing the phosphor ink, the ink server 51
A pressurizing pump 52 that pressurizes and sends out the phosphor ink in the inside;
A nozzle head 53 for discharging the phosphor ink sent from the pressure pump 52, and a substrate mounting table 5 for mounting a substrate (the rear glass substrate 21 on which the stripe-shaped partition walls 30 are formed).
6. Back glass substrate 21 mounted on substrate mounting table 56
A groove position detecting head 55 for detecting the position of the groove 32 (between the partition walls 30) is provided.

In the ink coating apparatus 50, the rear glass substrate 21 is mounted on the substrate mounting table 56 by the partition wall 30 as shown in FIG.
They are arranged along the axial direction. In addition, the nozzle head 5
A drive mechanism (not shown) for driving the head 3 and the groove detection head 55 relative to the substrate mounting table 56 is provided. In accordance with an instruction from the controller 60, an X-axis is formed along the surface of the substrate mounting table 56. The scanning can be performed in the direction and the Y-axis direction. As the driving mechanism, the nozzle head 53 and the groove detecting head 55 or the substrate mounting table 56 are driven by using a feed screw mechanism, a linear motor, or an air cylinder mechanism used in a three-axis robot or the like. Just do
A specific example will be described in Embodiment 2.

The substrate mounting table 5 of each of the heads 53 and 55
A position detecting mechanism (not shown) for detecting the positions in the X-axis and Y-axis directions on the line 6, that is, (X, Y) coordinates is provided, and the controller 60 can detect these coordinate positions. A linear sensor may be provided as the position detection mechanism. For example, in an X-axis or Y-axis drive mechanism,
In the case of using a drive source such as a pulse motor that can accurately control the drive amount, if a reference position detection sensor capable of detecting the X-axis or Y-axis reference position when it passes is provided, the drive X-axis or Y-axis from source driving amount
Axial position can be measured.

The nozzle head 53 is formed integrally with the ink chamber 53a and the nozzle 54 by machining and electric discharge machining of a metal material.
The phosphor ink supplied from the pressure pump 52 is temporarily stored in the ink chamber 53a, and continuously ejects an ink jet from the nozzle 54. Here, it is assumed that the nozzle head 53 is provided with only one nozzle 54, but it is also possible to provide a plurality of nozzles 54 to eject a plurality of ink jets. At 53a, the phosphor ink is distributed and the pressure applied to each nozzle is made uniform. The diameter of the nozzle 54 is preferably set to be considerably smaller than the pitch of the partition walls in consideration of preventing the ink jet from protruding from the groove between the partition walls as described later with reference to FIG. It is also necessary to prevent clogging. Usually, it is set in the range of about several tens to several hundreds of micrometers,
This also changes depending on conditions such as the amount of phosphor ink discharged.

The ink server 51 is provided with a stirrer 51a for preventing particles (such as phosphor particles) in the stored phosphor ink from settling. The groove detecting head 55 is scanned along the surface of the rear glass substrate 21 placed on the substrate placing table 56, and the characteristics (for example, the amount of light reflected from the surface,
This measures the dielectric constant of the surface, etc., and based on the measurement result of the groove detecting head 55, the position information of each groove 32 in the rear glass substrate 21 can be obtained.

Here, as shown in FIG. 3, the groove detecting head 55 includes a CCD line sensor 57 extending in the Y-axis direction and a light reflected from the upper surface of the rear glass substrate 21 on the CCD line sensor 57. A lens 58 for imaging is provided, and image data of the upper surface of the rear glass substrate 21 corresponding to the width of the CCD line sensor 57 in the Y-axis direction is taken in and sent to the controller 60.

[Description of groove position detection and ink application operation by ink application device 50]
0, the position information of the grooves 32a, 32b, 32c between the partition walls 30 is obtained, and based on the position information, the positions of the grooves 32a, 32b, 32c passing through the nozzle head 53 are controlled, and the phosphor ink of each color is applied to the grooves 32a, 32b, 32c. In order. Hereinafter, specific examples will be described.

First, the operation of mounting the rear glass substrate 21 on the substrate mounting table 56 and imaging the groove detecting head 55 while scanning it in the X-axis direction is repeated while being shifted in the Y-axis direction. , The image data over the entire surface of the rear glass substrate 21 is sequentially sent to the controller 60. The controller 60 takes in the image data sent from the groove detecting head 55 and stores the image data in which the coordinates on the substrate mounting table 56 correspond to the brightness in the memory.

FIG. 4 schematically shows the image data obtained in this manner. In the figure, the hatched portions correspond to the back glass substrate 21, and the white portions therein represent the partition walls 30. This is a portion corresponding to the upper surface. Next, a scan line is set based on the obtained image data. In this image data, the grooves 32a, 32b, 32c between the partition walls 30 are distinguished from each other by hatching and white display in FIG.
And the portion corresponding to the upper surface of the partition 30 are considered to have different luminance levels (generally, the groove portion is darker because the amount of reflected light is smaller than that of the partition upper surface portion). If the location where the luminance level changes suddenly is regarded as the edge of each groove 32a, 32b, 32c (the boundary line between the groove and the partition), and the scanning line S is set at the middle of both edges in each groove 32a, 32b, 32c. Good.

Hereinafter, a method for setting the scanning line S will be described more specifically. In the image data of FIG. 4, a plurality of search lines L are drawn at an equal pitch in parallel with the Y axis so as to cross the partition 30. FIG. 5A is a partially enlarged view of FIG. 4, in which search lines L1, L2, L3,.
Has been drawn.

FIG. 5B is a graph schematically showing the luminance at each position on the search line L1.
At the position corresponding to the upper surface of the groove, the grooves 32a, 32b,
A state where the luminance is low at a position corresponding to 32c is shown. On the search line L1 in FIG. 5A, points (P11, P12, P13,...,
P18), that is, the rising and falling Y coordinates in the graph of FIG. 5B are obtained. Similarly, for the search lines L2, L3,... L6 in FIG. 5 (a), the luminance change points (P21, P22, P
23,..., P28), luminance change points (P31, P32, P33,.
P38), ... luminance change point (P61, P62, P63, ..., P68)
Is determined.

Then, the midpoint Q1 between the luminance change points P11 and P12
1. The coordinates of the midpoint Q21 of the luminance change points P21 and P22,..., The midpoint Q61 of the change P61 and the midpoint Q61 of P62 are determined, and the midpoint Q11, the midpoint Q21,.
By connecting the midpoint Q61, a scan line S1 for the left end groove 32a in FIG. 5A is set. FIG.
Similarly, for the second, third, and fourth grooves from the left in (a), the scanning lines S2, S3, and S4 are set by connecting the coordinates of the middle point of the luminance change point.

After the scanning line S is set in this manner, the phosphor ink is ejected from the nozzle 54 while scanning the nozzle 54 along each scanning line, so that the grooves 32a, 32b, and 32c are filled with the phosphor ink. Is applied. Specifically, this is performed as follows. First, the ink server 51
, A phosphor ink of the first color (for example, blue) among blue, green, and red is added.

The controller 60 moves the nozzle head 53 to the end of the scanning line S of the groove 32a to be coated first, and drives the pressure pump 52 to pump the phosphor ink. Thus, the phosphor ink is discharged from the nozzle 54 as a continuous flow. The distance between the lower end of the nozzle 54 and the upper surface of the partition wall is usually set to 0.5 to 3 mm, depending on conditions such as the amount of ink discharged.

In this state, the controller 60 scans the nozzle head 53 in the X direction.
The scanning is performed while also adjusting the position of the nozzle head 53 in the Y direction so as to follow. The controller 60 then controls the nozzle head 5
3 is shifted in the y-axis direction, and the groove 32 to be applied next is shifted.
By moving the nozzle head 53 to the end of the scan line S in FIG. a and scanning the rear glass substrate 21 at a high speed in the opposite direction while discharging the phosphor ink from the nozzle, the nozzle 54 is moved along the scan line S. The phosphor ink is applied while scanning the nozzle head 53. Then, by repeating such an operation, the first color phosphor ink is applied to all the grooves 32a in the rear glass substrate.

Next, similarly, in the adjacent groove 32b,
The second color (for example, green) phosphor ink is applied, and the third color (for example, red) phosphor ink is applied to the adjacent groove 32c. Thereby, the phosphor inks of three colors are applied to the grooves 32a, 32b, 32c. According to the method for applying the phosphor ink as described above, even if the grooves 32a, 32b, and 32c are inclined with respect to the X axis as shown in FIG. 6A, or as shown in FIG. As groove 32
Even if a, 32b, and 32c are curved, the scanning line S is set so as to always pass through the center of each groove, and the nozzle 54 is scanned along the scanning line S. The phosphor ink is applied to the sides of the partition walls on both sides of the groove, and the phosphor ink is uniformly applied along the groove.

That is, when the grooves 32a, 32b, 32c are inclined or curved with respect to the X axis as shown in FIGS. 6A and 6B, the nozzle 54 is temporarily moved in the Y axis direction. 7A, the nozzle 54 is displaced from the center of the groove 32 and approaches one of the partition walls 30 (the left side in FIG. 7), as shown in FIG. 7A. There is a portion, and in such a portion, a large amount of the phosphor ink easily adheres to the side wall of the closer partition wall, and the formed phosphor layer is also formed on the side wall of one partition wall as shown in FIG. It is easily formed thick. And in extreme cases nozzle 5
There is also a possibility that the color of 4 may be out of the groove and mixed. On the other hand, if the coating method of the present embodiment is used, the phosphor ink is uniformly applied to both sides at any location.

It is to be noted that such an effect can be obtained even if the nozzle does not necessarily scan directly above the set scanning line, but scans without leaving much from each scanning line. (Regarding the control of the discharge amount of the phosphor ink) By the way, if the pitch of the partition 30 is constant and the groove width of each of the grooves 32a, 32b, 32c is uniform, the scanning speed of the nozzle and the discharge amount of the ink (per unit time) (The discharge amount from the nozzle) may be set to a constant value, but if the groove width varies or the width fluctuates in the groove, the nozzle scanning speed and the ink discharge amount may be fixed. Then, the adhesion state of the phosphor ink (the adhesion balance to the bottom and side surfaces of the groove) becomes uneven. This is because the phosphor ink to be applied is dispersed over a wider area in a place where the groove width is wide than in a place where the groove width is narrow, so that the phosphor ink is less applied to the side wall of the partition wall.

Further, where the groove width is small, the amount of the phosphor ink applied becomes excessive, and there is a possibility that the adjacent grooves overflow and cause color mixing. On the other hand, the problem can be solved by controlling the discharge amount by adjusting the pressure for pressing the phosphor ink or controlling the scanning speed in accordance with the fluctuation of the groove width as described below. In the image data of FIG. 4, each groove 32a, 3
The groove width of each of the grooves 2b and 32c is measured, and based on the measured ink width when the nozzle 54 is scanned, the amount of ink applied per unit length in the X-axis direction is proportional to the groove width. The pressure of the pressurizing pump 52 or the driving speed by the X-axis driving mechanism is controlled.

For example, for the scanning line S1 in FIG. 5A, the groove width at point Q11 (distance between points P11 and P12), the groove width at points Q21,.
Then, when scanning the scanning line S1 with the nozzle 54,
When the nozzle 54 passes over the points Q11, Q21,..., Q6, the pressing force of the pressurizing pump 52 is made proportional to the measured groove width.

By controlling in this manner, the amount of the phosphor ink applied per unit length in the X-axis direction is substantially proportional to the groove width. The adhesion state of the phosphor ink becomes uniform, and color mixing does not occur even in a place where the groove width is small. In this embodiment, an image of the entire upper surface of the rear glass substrate 21 is taken by the groove detecting head 55, and the groove position information is obtained from the image data. Although the example in which the scan line is set by using the scan line is described, the method of setting the scan line is not limited to this, and there are various methods.

For example, a luminance change point can be obtained by scanning a head provided with a CCD line sensor extending in the X-axis direction in the Y-axis direction so as to cross the partition wall 30. That is, if the luminance on the lines corresponding to the search lines L1, L2,... In FIG. 5A is detected, the luminance change point can be similarly obtained, and the scanning line can be set.

In the above embodiment, a point at which the luminance changes abruptly is detected and determined to be the edge of the groove. Similarly, it is also possible to scan the upper surface of the rear glass substrate 21, detect a point at which the distance from the distance sensor suddenly changes, and determine the point as the edge of the groove. Alternatively, a dielectric measurement sensor for measuring a dielectric constant is arranged on the groove detection head 55, and the upper surface of the rear glass substrate 21 is similarly scanned,
It is also possible to detect a point at which the dielectric material suddenly changes and determine it as the edge of the groove.

Further, in the ink applying device 50, the nozzle head 53 and the groove detecting head 55 can be driven independently of each other. However, even if these are driven integrally, the same operation as described above is performed. Can be done. In the ink coating device 50, the groove detecting head 55 is formed over the entire upper surface of the rear glass substrate 21 in advance.
Although the example in which the position of the groove is detected to set the scanning line and then the application of the phosphor ink is started has been described, it is also possible to perform the application in parallel. That is, while applying the phosphor ink by scanning the nozzle head 53, image data is obtained for a groove to which ink is to be applied later, and a scan line is set. When applying ink to the groove, the scan line is used. It is also possible to perform scanning while controlling the nozzle head 53 in accordance with.

That is, if a scanning line is set before scanning the nozzle head 53, the nozzle head 53 can be controlled in accordance with the setting, and it is considered that the same effect as in the above-described embodiment can be obtained. . Therefore, for example, a groove detector (CCD line sensor) for detecting the center position of a groove ahead of the nozzle head 53 in the scanning direction is provided, and when the nozzle head 53 is scanned, the nozzle detector It is also possible to detect the center position of the groove prior to the head 53 and scan while controlling the nozzle head 53 so as to pass through the detected center position. However, in this case, it is necessary to quickly detect the center position of the groove and drive the groove in the y-axis direction.

In addition to the above, a groove detector is attached to the nozzle head 53, and the nozzle head 53 calculates the positional deviation between the nozzle and the center position of the groove detected by the groove detector so as to eliminate the positional deviation. Can be performed in the y-axis direction to perform feedback correction. Further, in the above embodiment, the case where one nozzle 54 is provided in the nozzle head 53 has been described. However, the same can be applied to a case where a plurality of nozzles 54 are provided in the nozzle head 53.

In this case, scanning is performed while adjusting the nozzle head 53 in the Y-axis direction so that each nozzle 54 is along each scanning line. For example, the nozzle pitch is set to three times the partition pitch, and the position adjustment of the nozzle head 53 is performed by averaging each scanning line set at the center of each groove 32a as the scanning line of the nozzle head 53, Scanning is performed while adjusting the nozzle head 53 in the Y-axis direction so as to coincide with the scanning line.

Thus, the phosphor ink can be applied to a plurality of grooves in parallel. If the number of the nozzles 54 provided in the nozzle head 53 is one, the groove 3
Although the number of times of tact is required by the number of 2a, 32b, and 32c, the number of times of tact can be reduced by increasing the number of nozzles 54 provided in the nozzle head 53 as described above. For example, if three nozzles 54 are provided in the nozzle head 53, it is possible to apply three grooves in one scan, so that the number of tacts can be reduced to １ ／.

In a high-definition PDP, the rear glass substrate 21
The number of grooves 32a, 32b, and 32c provided in each is very large, from several hundreds to several thousands (for example, 16 in a 42-inch class:
In a 9-type VGA level PDP display device, there are about 850 grooves for each color, and in the HD type, there are 1920 grooves for each color.) Therefore, the working efficiency can be considerably improved by increasing the number of nozzles 54.

In this embodiment, the method of applying the next color after completing the application of the first color phosphor ink has been described. However, the ink application device 50 is provided with a nozzle head for three colors. Here, it is also possible to apply three color phosphor inks in parallel. [Composition of Phosphor Ink] (1) Phosphor Particles In order to suppress nozzle clogging and precipitation of the phosphor particles, the average particle diameter of the phosphor particles used in the phosphor ink is 5%.
It is good to be below μm. In order for the phosphor to obtain good luminous efficiency, the average particle diameter of the phosphor is preferably 0.5 μm or more. Therefore, it is preferable to use the phosphor particles having an average particle size of 0.5 to 5 μm, and particularly preferably 2 to 3 μm.
It is preferable to use those in the range of m.

In order to improve the dispersibility of the phosphor particles, it is effective to attach or coat an oxide or a fluoride on the surface of the phosphor particles as follows. Examples of metal oxides to be attached or coated on the surface of the phosphor particles include magnesium oxide (M
gO), aluminum oxide (Al ₂ O ₃ ), silicon oxide (SiO ₂ ), indium oxide (InO ₃ ), zinc oxide (ZnO), and yttrium oxide (Y ₂ O ₃ ). Among them, SiO ₂ is known as a negatively charged oxide, while ZnO, Al ₂ O ₃ , and Y ₂ O ₃ are known as positively charged oxides. Alternatively, coating is effective.

The particle size of the oxide to be attached is considerably smaller than the particle size of the phosphor particles, and the amount of these oxides attached to the surface of the phosphor particles is 0.05 to 0.05 to the phosphor particles.
Suitably, it is in the range of 2.0% by weight. This is because if the amount is less than this range, the effect is small, and if it is too large, vacuum ultraviolet rays generated in the plasma may be absorbed, and the panel luminance may be reduced.

Examples of the fluoride to be adhered or coated on the surface of the phosphor particles include magnesium fluoride (MgF ₂ ) and aluminum fluoride (AlF ₃ ). (2) Binder Ethyl cellulose or polyethylene oxide (a polymer of ethylene oxide) may be mentioned as a binder suitable for dispersing the phosphor particles well, and in particular,
Content of ethoxy group (-OC ₂ H ₅₎ is preferably used from 49 to 54% of ethylcellulose.

Further, a photosensitive resin may be used as the binder. (3) Solvent It is preferable to use a mixture of an organic solvent having a hydroxyl group (OH group) as a solvent. Specific examples of the organic solvent include terpineol (C ₁₀ H ₁₈ O), butyl carbitol acetate, Pentanediol (2,2,4
-Trimethylpentanediol monoisobutyrate),
Dipentene (also known as Limonen), butyl carbitol and the like.

A mixed solvent obtained by mixing these organic solvents is:
It is excellent in solubility for dissolving the above binder, and excellent in dispersibility of the phosphor ink. The phosphor content in the phosphor ink is 35 to 60% by weight,
The content of the binder is suitably in the range of 0.15% to 10% by weight. In order to adjust the shape of the phosphor ink applied to the grooves as described later, the content of the binder is preferably set to a large value within a range where the ink viscosity does not become too high.

(4) Dispersant By adding a dispersant to the phosphor ink having the above composition, the dispersibility of the phosphor particles in the ink can be improved. Examples of the dispersant include the following surfactants. * Anionic surfactants: fatty acid salts, alkyl sulfates, ester salts, alkyl benzene sulfonates, alkyl sulfosuccinates, naphthalene sulfonate polycarboxylic acid polymers.

* Nonionic surfactant: polyoxyethylene alkyl ether, polyoxyethylene derivative, sorbitan fatty acid ester, glycerin fatty acid ester,
Polyoxyethylene alkylamine. * Cationic surfactants: for example, alkylamine salts,
Quaternary ammonium salts, alkyl betaines, amine oxides.

(5) Static elimination substance It is also preferable to add a static elimination substance to the phosphor ink. The surfactants mentioned as the dispersants in the above (4) generally also have a charge eliminating action for preventing the charging of the phosphor ink, and many of them correspond to charge eliminating substances. However, phosphor,
Since the static elimination action differs depending on the type of the binder and the solvent, it is preferable to conduct a test on various types of surfactants and select a surfactant having a good result.

The addition amount of the surfactant is from 0.05 to
The amount is preferably 0.3% by weight. If the amount is less than this range, the effect of improving the dispersion or the effect of eliminating static electricity cannot be expected much. Examples of the charge removing substance include fine particles made of a conductive material in addition to the surfactant.

Examples of the conductive fine particles include fine powders of carbon such as carbon black, fine powders of graphite, fine powders of metals such as Al, Fe, Mg, Si, Cu, Sn and Ag, and metal oxides thereof. Fine powder. The amount of such conductive fine particles to be added to the phosphor ink is preferably in the range of 0.05 to 1.0% by weight.

The addition of a charge eliminating substance to the phosphor ink prevents the phosphor ink from being charged.
The following effects are produced in PDP production. If the discharge substance is not added to the phosphor ink, there is a problem that stripes are apt to be generated when the manufactured panel is driven. However, the stripe unevenness is caused by adding the discharge substance to the phosphor ink. Is suppressed.

If the charge eliminating substance is not added to the phosphor ink, a problem that the phosphor layer swells at the break of the address electrode 22 at the center of the panel (see FIG. 2) due to the charging of the phosphor ink is likely to occur. But,
This can also be suppressed by adding a charge eliminating substance to the phosphor ink. In these, when the phosphor ink (especially one using an organic solvent) is charged at the time of application, a slight variation occurs in the amount of the phosphor ink applied to each groove and the state of adhesion to the groove. This is presumably because the charge is prevented by adding a charge removing substance to the ink.

Further, by suppressing the charge, it is possible to prevent color mixing due to scattering of a suitable liquid. Further, when a surfactant or carbon fine powder is used as the charge removing substance as described above, the charge removing substance is also evaporated or burned off in the phosphor baking step for removing the solvent and the binder contained in the phosphor ink. Therefore, no charge removing substance remains in the phosphor layer after firing. Therefore, there is no possibility that driving (light emitting operation) of the PDP will be affected by the residual charge removing substance remaining in the phosphor layer.

[Production Method of Phosphor Ink] The phosphor ink is prepared by adding the above binder to a solvent in an amount of 0.2%.
To 10% by weight, phosphor particles of each color are prepared, and the phosphor particles are dispersed using a disperser. As a disperser for producing phosphor ink,
In addition to vibration mills and stirring tank mills (ball mills, bead mills, sand mills, etc.) that disperse using balls, flow tube mills, jet mills that disperse without using balls,
A nanomizer and the like can be given.

As a dispersion medium (media) for a vibration mill or a stirred tank type mill, zirconia or alumina balls are used, and in particular, zirconia (ZrO ₂ ) having a diameter of 0.2 to ₂ mm.
Preferably, a ball is used. This is to suppress damage to the phosphor powder and to suppress contamination (contamination) of impurities. When using a jet mill, 10
The dispersion is preferably performed in a pressure range of 100 kgf / cm ² . This pressure range is preferably 10 kgf / cm
^If it is less than ² , sufficient dispersion cannot be obtained, and 100 kgf / cm ²
This is because, if it exceeds, the phosphor particles tend to be crushed.

The viscosity of the phosphor ink (viscosity at 25 ° C. and a shear rate of 100 sec ⁻¹ ) is adjusted to 2,000 centipoise or less, preferably in the range of 10 to 500 centipoise. As a method of attaching an oxide or a fluoride to the surface of the phosphor particles, for example, magnesium oxide (MgO), aluminum oxide (Al ₂
O ₃ ), silicon oxide (SiO ₂ ), indium oxide (InO
A suspension of a metal oxide such as ₃ ) or a suspension of a metal fluoride such as magnesium fluoride (MgF ₂ ) or aluminum fluoride (AlF ₃ ) is added, and the mixture is mixed and stirred. It can be carried out by drying at a temperature of at least ℃ and firing at 350 ℃. Here, in order to improve the adhesion between the phosphor particles and the oxide or fluoride, a small amount of resin, silane coupler or water glass is added to the suspension. Is also good.

For example, in order to coat the surface of the phosphor particles with a film of aluminum oxide (Al ₂ O ₃ ), aluminum alkoxide Al (OC)
To ₂ H _{5) 3} in alcoholic solution can be carried out by stirring by adding phosphor particles. [Function and Effect of Phosphor Ink of the Present Embodiment] As described above, the phosphor ink of the present embodiment has excellent dispersibility, so that when applied to the groove between the partition walls, it has good adhesion to the side wall of the partition wall. is there. The principle will be described below.

FIG. 8 is a diagram schematically showing a state in which a phosphor layer is formed after the phosphor ink is applied to the groove between the partition walls. When the phosphor ink having good fluidity is filled between the partition walls 30, the phosphor particles in the filled phosphor ink include:
Gravity F1 works and tries to settle it to the bottom. on the other hand,
A force F2 for moving the phosphor particles in the phosphor ink toward the partition wall side surface also acts. The force F2 is a force that tends to pull the phosphor particles mutually bound by the binder in the direction of the partition wall as the solvent in the phosphor ink diffuses into the partition wall 30.

The shape of the phosphor layer finally formed in the groove between the partition walls is determined by the balance between these forces F1 and F2. The better the dispersibility of the phosphor ink, the more the force F2 Therefore, it is considered that the adhesion of the phosphor ink to the side wall of the partition wall is improved. Also,
As described above, according to the same principle, it is preferable to set the content of the binder in the phosphor ink to a large value. Since the force F2 is improved by setting the content of the binder to a large value, The adhesion of the phosphor ink to the side wall of the partition is improved.

When the adhesion of the phosphor to the side wall of the partition is improved, the ratio of the phosphor layer formed on the side wall of the partition is increased, which contributes to the improvement of the panel brightness of the PDP. This is because ultraviolet light generated near the display electrode can be efficiently converted into visible light. FIG. 9 schematically shows how the shape of the formed phosphor layer changes when the concentration of the resin binder in the phosphor ink is changed.

As shown in this figure, when the resin concentration is low, the phosphor particles settle almost at the bottom, and the phosphor layer is formed only at the bottom.
Since the bonding force between the phosphor particles increases, the amount of the phosphor adhered to the side wall of the partition wall increases, and when the resin concentration component becomes higher than a certain level, the phosphor layer is formed only on the side wall of the partition wall.

In the case where the phosphor inks of a plurality of colors are sequentially applied to the grooves, when the phosphor inks of the second and third colors are to be applied, the phosphors are already in the adjacent grooves. Since the ink is applied, the solvent has already penetrated the partition walls. For this reason, the solvent in the phosphor ink newly applied to the groove hardly penetrates into the partition walls. Therefore, when the phosphor ink having poor dispersibility is used, the force F2 hardly works.

However, if the phosphor ink having good dispersibility is used as in the present embodiment, even if the phosphor ink is applied to the adjacent groove, a certain force F2 acts, so The adhesion of the phosphor ink to the phosphor is relatively good. Usually, the diameter of the nozzle 54 is set to be considerably smaller than the partition wall pitch, and it is necessary to set the ink viscosity to be considerably low in order to stably discharge the phosphor ink from the thin nozzle. As shown in FIG. 10, it is necessary to lower the viscosity by about two orders of magnitude compared to the viscosity of ink used in conventional screen printing and the like.

For this reason, clogging is likely to occur in the nozzles. However, since the phosphor ink of the present embodiment has good dispersion of the phosphor particles, clogging of the nozzles does not easily occur. It is possible to apply for a period of time, and it is also possible to apply continuously for 100 hours or more.
The reason why the diameter of the nozzle 54 is set to be considerably smaller than the partition wall pitch is as follows.

FIG. 11 is a diagram showing the state of discharge of the phosphor ink from the nozzles. As shown in FIG. 11A, the phosphor ink tends to expand after the phosphor ink is discharged from the nozzle. This is the so-called ballast effect. Considering this point, the nozzle diameter d
Needs to be considerably smaller than the partition wall pitch.
For example, in the case of a VGA class partition having a pitch of 360 μm,
It is necessary to set the nozzle diameter d to around 100 μm.
In the D class, it is necessary to set the nozzle diameter d to a very small value of about 50 μm.

(Modification of Method for Applying Phosphor Ink)
When the discharge is stopped after the low-viscosity phosphor ink is discharged from the nozzle, as shown in FIG. 11B, the flow after the stop is shifted in the axis of the jet flow, and the flow tends to be unstable. . The reason for this is that when the discharge of the ink is stopped, the phosphor ink adheres to the periphery of the nozzle at the tip of the nozzle (the lower surface of the nozzle), and the wettability changes slightly. It becomes remarkable when the viscosity of the ink is small.

As a countermeasure against this, the phosphor ink may be continuously ejected from the nozzle 54 while the phosphor ink is continuously ejected to the plurality of grooves. In other words, even when the nozzle 54 is located at a position out of the groove, the application of the coating method in which the discharge of the phosphor ink is continued without stopping can be used to prevent the phosphor ink from adhering to the lower surface of the nozzle tip. The displacement of the axis of the ink jet jet as shown in b) can be prevented.

For example, if the phosphor ink is continuously ejected until the application of one color to the entire rear glass substrate 21, the axis deviation of the ink jet jet can be prevented during that time, so that the ink jet jet can be stabilized. Can be applied. [Embodiment 2] FIG. 12 is a perspective view showing an ink applying apparatus according to the present embodiment, and FIG. 13 is a front view (partial cross section) of the ink applying apparatus.

This ink application device has basically the same configuration as the above-described ink application device 50, except that a nozzle mechanism having a plurality of nozzles or a circulating mechanism for collecting and using the phosphor ink is rotated to reduce the nozzle pitch. The device is provided with a nozzle rotating mechanism for adjustment. (Structure of Ink Applying Apparatus) The ink applying apparatus includes an apparatus main body 100 and a controller 200.

The apparatus main body 100 includes a main body base 101,
The substrate mounting table 103 moves in the X-axis direction (the arrow X direction in the figure) along the rail 102 laid on the upper surface of the main body base 101, and the rail 105 of the arm 104 provided so as to straddle the main body base 101. Nozzle unit 110 that moves in the Y-axis direction (the arrow Y direction in the figure) along the same direction, similarly moves arm 104 in the Y-axis direction and
An imaging unit 120 for detecting the position of the partition wall of the rear glass substrate 21 mounted thereon is provided.

An X drive mechanism 1 for reciprocatingly driving the substrate mounting table 103 in the X-axis direction is provided inside the main body base 101.
30 are provided. The X drive mechanism 130 includes a drive motor 131 (for example, a servo motor or a stepping motor), a feed screw 132 extending in the X-axis direction along the rail 102, and a nut 133 fixed to a lower portion of the substrate mounting table 103. By rotating the feed screw 132 with the drive motor 131, the substrate mounting table 103 can be slid in the X-axis direction at a high speed together with the nut 133.

FIG. 14 is an enlarged view of the nozzle head unit 110 shown in FIG. Nozzle head unit 11
To 0, the height of the drive base 111 having a built-in Y-axis drive mechanism for reciprocating the same in the Y-axis direction, the nozzle head 112 having a plurality of nozzles 113 arranged in parallel, and the height of the nozzle head 112 are adjusted The lifting mechanism 114 for raising and lowering this, and the nozzle head 112
A rotation drive mechanism 115 is provided for rotating and driving in a plane parallel to.

As the Y-axis drive mechanism and the elevating mechanism 114, for example, a linear motor or a slide mechanism combining a drive motor with a pinion gear and a rack gear can be applied. Further, as the rotation drive mechanism 115, for example, a servomotor is used, and the nozzle head 112 is rotated around the rotation shaft 112 a. The imaging unit 120 can be driven on the arm 104 in the Y-axis direction by a Y-axis driving mechanism (not shown), similarly to the drive base 111. The imaging unit 120 includes the groove detecting head 5 described in the first embodiment.
Similarly to 5, a CCD line sensor extending in the Y-axis direction and the like are built in, and upper surface image data of the rear glass substrate 21 mounted on the substrate mounting table 103 can be obtained.

Although not shown, the ink application apparatus includes an X-position detecting mechanism for detecting the position of the substrate mounting table 103 in the X-axis direction, and the positions of the nozzle head unit 110 and the imaging unit 120 in the Y-axis direction. A linear sensor (for example, an optical linear encoder) is provided in each of the X-axis direction, the Y-axis direction, and the up-and-down direction as a Y position detection mechanism for detecting and a height detection mechanism for detecting the height position of the lifting mechanism 114 Accordingly, the controller 200 controls the positions of the nozzle head unit 110 and the imaging unit 120 (the X coordinate and the Y axis coordinate on the substrate mounting table 103) and the position of the nozzle head 112 based on signals from the respective linear sensors. The height can be detected at any time.
Further, the angle θ of the nozzle head 112 with respect to the X axis can be detected at any time by an angle detection mechanism (for example, a rotary encoder).

The nozzle head 112 and the imaging unit 120 are provided by the above-described driving mechanisms and detecting mechanisms.
Can scan in the X-axis direction and the Y-axis direction along the substrate mounting table 103. Further, the nozzle head 112
The height from the substrate mounting table 103 and the angle with respect to the X axis can be adjusted. Further, as shown in FIGS. 12 and 13, a suction pump 141 and the suction pump 141 and the substrate mounting table are provided inside the main body base 101 in order to constitute a substrate suction mechanism 140 for sucking the substrate on the substrate mounting table 103. Flexible hose 14 connecting to 103
2 are provided. Further, a cavity 103a (see FIG. 13) is formed inside the substrate mounting table 103, and a large number of fine holes communicating with the cavity 103a are provided on the upper surface of the substrate mounting table 103. And the suction pump 1
By exhausting the air from the cavity 103a at 41, the substrate on the substrate mounting table 103 can be sucked.

As shown in FIGS.
0, a circulating mechanism 1 for collecting, circulating, and using the phosphor ink discharged from the nozzle head unit 110.
50 are provided. The circulation mechanism 150 includes a collection container 151 for collecting the phosphor ink (ink jet) discharged from the nozzle head unit 110 and a pressure pump 15 for pressurizing and sending the phosphor ink in the collection container 151.
2 and so on.

The collection container 151 extends in the Y-axis direction so that the ink jet can be collected over the entire scanning range of the nozzle head unit 110. The collected phosphor ink is supplied from the pressure pump 152 via the pipe 153. Thus, the ink is supplied to the nozzle head 112 in the nozzle head unit 110 and circulated for use. Further, the circulation mechanism 150 is provided with an ink replenisher 154 for keeping the amount of the circulating phosphor ink constant.
The ink replenisher 154 monitors whether or not the amount of ink in the collection container 151 is equal to or more than a specified amount, and automatically replenishes the phosphor ink when the amount becomes equal to or less than the specified amount.

Further, in order to prevent the ink jet discharged from the nozzle head 112 from adhering to the end of the rear glass substrate 21, a jet shielding mechanism 116 is provided in the nozzle head unit 110. The jet shielding mechanism 116 includes a shielding tray 117 that slides in the X-axis direction and a solenoid (not shown) that slides the shielding tray 117. The shielding tray 117 is normally retracted from the ink jet passage line. Can be slid to a position where the ink jet is shut off by driving the.

The phosphor ink shielded by the shielding tray 117 is transferred to the second collection container 118 by a suction pump (not shown). The controller 200
It controls the driving of each part of the apparatus main body 100. The controller 200 includes the drive motor 131, the nozzle head unit 110, the imaging unit 120, the suction pump 141, the pressure pump 152, and the cables 201 to 20.
These components are driven by power and drive control signals supplied from the controller 200 through the respective cables.

The image data obtained by the imaging unit 120 is sent to the controller 200 through the cable 203. (Operation and Operation Control of Ink Applying Apparatus) A procedure for applying the phosphor ink using such an apparatus configuration will be described. First, the rear glass substrate 21 is placed on the substrate mounting table 103.
It is placed on the top, and is suction-fixed by operating the suction pump 141.

Next, the ink coating device 50 of the first embodiment
In the same manner as described above, the imaging unit 120 is scanned to capture an image over the entire surface of the rear glass substrate 21, and the controller 200 uses the image data from the imaging unit 120 to scan the substrate mounting table 103. Image data in which the coordinates and the brightness correspond to each other is obtained, and a scanning line is set in a groove between the partition walls.

Next, the elevation mechanism 114 is driven to adjust the height of the nozzle head 112 so that the nozzle 11
The distance between the lower end of 3 and the upper surface of the partition 30 is adjusted. And
By driving the pressure pump 152, the nozzle head unit 1
10 discharges the phosphor ink. Then, while keeping the state where the ink is ejected, the nozzle head unit 110 is scanned as described below to apply the phosphor ink.

FIG. 15 is a diagram showing a state in which the nozzle head 112 is scanned over the rear glass substrate 21. Here, a case where one color (blue) phosphor ink is applied to every third groove 32a will be described. In the nozzle head 112, three nozzles 113a, 113b and 113c are arranged in a straight line at a distance A, and the nozzle interval A is 2
It is set slightly larger than the pitch of every other groove 32a,
It is assumed that the position of the center nozzle 113b matches the rotation center of the nozzle head 112.

In this figure, a thick arrow (R1 → R2 → R3
(→ R4 →) indicates a line where the center of the nozzle head 112 is scanned. As shown in FIG.
Scanning is performed in the X-axis direction while the nozzle head 112 is tilted with respect to the Y-axis so that 113b and 113c are positioned on every third groove 32a (R1 → R2). Next, the nozzle head 112 is shifted in the Y-axis direction by nine partition pitches (R2 → R3), and scanning is performed in the X-axis direction while the nozzle head 112 is similarly tilted with respect to the Y-axis ( R3 → R
Four).

Thereafter, by repeating the same scanning, the phosphor ink is applied to each groove 32a over the entire rear glass substrate 21, but during this time, the phosphor ink is continuously applied without stopping the pressure pump 152. Let it be discharged. Thereby, the nozzles 113a, 113b, 1
This prevents the jet flow from becoming unstable due to the phosphor ink adhering to the lower surface of 13c.

During the scanning of the nozzle head 112 in the X direction, the area between the end of the partition wall 30 and the edge of the substrate mounting table 103 (the area indicated by W1 and W2 in the figure) is defined as the nozzle head. At the time when 112 passes, the ink blocking mechanism 116 is operated to block the ink jet at the blocking tray 117. Thereby, it is possible to prevent the phosphor ink from adhering to the vicinity of the end of the partition 30 on the rear glass substrate 21 (regions indicated by W3 and W4 in the drawing).

When the viscosity of the phosphor ink is low, the groove 3
2a is applied near the end of the partition 30 (W
3, W4 area), the adhering ink will be in the next groove 3
There is a possibility that the mixture flows into the groove 2b or the groove 32c and causes color mixing. However, by preventing adhesion as described above, the color mixing can be prevented. In addition, this jet shielding mechanism 1
In 16, the shielding tray 117 needs to enter between the lower end of the nozzle 113 and the upper surface of the partition 30. Therefore, it is conceivable that the shielding tray 117 is designed to be thin. However, the thickness of the shielding tray 117 is secured so that phosphor ink can be stored to some extent, and the lifting mechanism 114 is moved in accordance with the timing at which the jet shielding mechanism 116 is operated. It is preferable that the nozzle head 112 be driven to move upward.

Further, when the ink is applied while circulating the ink continuously, not only the amount of the ink in the container is reduced, but also the physical property value is liable to change due to evaporation of the solvent. Therefore, it is preferable to take measures to prevent the physical properties of the phosphor ink from exceeding an allowable range. For example, the viscosity of the ink can be kept constant by detecting a viscosity in the collection container 151 and automatically providing a solvent replenishing mechanism for replenishing the fluorescent ink with a solvent or the like. Thereby, stable application can be performed for a long time.

The ink received by the jet shielding mechanism often has different physical property values from the ink received by the simple collecting container. Therefore, the ink received by the jet shielding mechanism is different from the circulating ink. It is preferable to store it in the second collection container 118 and reuse it separately. [Position Control of Nozzle Head 112] In this embodiment, as in Embodiment 1, when scanning the nozzle head 112 in the X-axis direction, the scanning is performed while adjusting in the Y-axis direction. Then, the nozzle head 112 is rotated by the rotation drive mechanism 115, so that scanning is performed while adjusting the nozzle pitch of the nozzle head 112 in the Y-axis direction.

That is, the three nozzles 113a, 113b,
Nozzles 113a and 113 at both ends in 113c
Scanning in the X-axis direction is performed while adjusting the position and rotation angle of the nozzle head 112 in the Y-axis direction so that c is along the line set at the center of the corresponding groove 32a. By performing scanning while controlling in this manner, even if the grooves 32a, 32b, and 32c are curved or the pitch between the partition walls is changed, the plurality of nozzles 113a, 113b, and 11 in the nozzle head 112 are controlled.
3c can be scanned along a scanning line set at the center of each corresponding groove 32a. Hereinafter, this control will be described more specifically.

FIG. 16 is a partially enlarged view of image data in which the coordinates on the substrate mounting table 103 correspond to the luminance, and shows a case where the grooves 32a, 32b, 32c are curved in the X-axis. . On this image data, as described with reference to FIG. 5 of the first embodiment, the nozzle scan lines S1, S2, S3
Set…. Then, as shown in the figure, the length is 2A.
And the line segments K1, K2, K3... Having both ends on the nozzle scanning line S1 and the nozzle scanning line S7 are set at substantially equal pitches.

For each of the line segments K1, K2, K3,..., The position (X, Y coordinate) of the midpoint M1, M2, M3.
The angles θ1, θ2, θ3,... With respect to the axis are calculated. The line connecting the midpoints M1, M2, M3,.
Scan line of nozzle head 112 (head scan line)
And As can be seen from FIG. 16, the head scan line almost coincides with the nozzle scan line S4, although there is a slight shift.

When scanning the nozzle head 112, while rotating the nozzle head 112 in the X-axis direction, the center of rotation (nozzle 113b) of the nozzle head 112 is aligned with the head scan line (middle point M1, M2, M3). ) Of the nozzle head unit 110 so that
Drive control of the shaft drive mechanism. At the same time, the rotation center of the nozzle head 112 is set at the calculated midpoints M1, M2, M3.
..., the driving of the rotary drive mechanism 115 is controlled so that the angle θ of the nozzle head 112 with respect to the x-axis matches the calculated angles θ1, θ2, θ3,.

By controlling the Y-axis direction and the rotation angle θ during the scanning of the nozzle head 112, the nozzles 113a and 113c at both ends are moved to the scanning line S.
1, S7 is scanned, and the central nozzle 113 is scanned.
a is scanned on the head scanning line (that is, in the vicinity of the nozzle scanning line S4). Therefore, each nozzle 11
3a, 113b, and 113c are always scanned near the center of each groove 32a.

[Effect of Provision of Mechanism for Recovering Phosphor Ink] When the nozzle is off the groove of the substrate, that is, when the substrate is in the standby state as shown in FIG. Since the ink jet is collected in the collection container 151, there is almost no loss even if the phosphor ink is continuously discharged.

Therefore, for example, if the ink is continuously ejected even when the rear glass substrate 21 on the substrate mounting table 103 is exchanged, the ink can be stably applied to a plurality of substrates 21 and the fluorescent light can be applied. Less body ink loss. Furthermore, the discharge of the phosphor ink from the nozzles may be basically stopped only at the time of maintenance, and thereafter, the discharge may be performed continuously. Therefore, in a production factory that operates all day, the discharge is continuously performed for 24 hours or more. And may be operated continuously on a weekly or monthly basis.

As described above, the coating method of the present embodiment is an excellent method suitable for mass production because the loss of the phosphor ink is small and the coating between the partition walls can be uniformly and stably performed. The manufacturing method according to the embodiment can also reduce the manufacturing cost. [Regarding Modification According to the Present Embodiment] Considering the adaptability when changing the operation procedure, the nozzle head unit 110 and the imaging unit 120 are independent on the arm 104 as shown in FIG. Although it is desirable that the nozzle head unit 110 and the imaging unit 120 be integrated, the same operation as described above is possible.

Further, in the present embodiment, as a method of preventing color mixture of the phosphor ink at the end of the partition wall of the rear glass substrate 21, a method of shutting off the ink jet has been described. For example, as shown in FIG. , Back glass substrate 2
1, if the auxiliary partition wall 33 is formed along the end of the partition wall 30, the grooves 32a, 32b, 3
Since 2c is closed, even if the phosphor ink applied to the groove 32a adheres to the vicinity of the end of the partition on the rear glass substrate 21, it does not flow into the adjacent grooves 32b and 32c, so that color mixing can be prevented.

[Embodiment 3] The ink applying apparatus of the present embodiment is the same as the ink applying apparatus of Embodiment 2 described above, but further devise a circulation mechanism for circulating the phosphor ink. FIG. 18 is a diagram illustrating a configuration of a phosphor ink circulation mechanism in the ink application device of the present embodiment.

The circulating mechanism 160 is similar to the circulating mechanism 150 of the second embodiment, and is similar to the circulating mechanism 150 of the second embodiment.
The phosphor ink ejected from the nozzle 13 is collected in a collection container 151, and the collected phosphor ink is re-used in the nozzle head 1 again.
12 for circulation.
A disperser 161 for redispersing the phosphor ink is interposed in a piping route from the nozzle head 112 to the nozzle head 112.

The disperser 161 is a flow tube type sand mill filled with zirconia beads having a particle size of 2 mm or less. The rotating disk 163 rotates in a fixed direction at a rotation speed of 500 rpm or less. Is dispersed together with the beads by stirring. The circulation mechanism 160 also includes a collection container 151
A circulating pump 164 that feeds the disperser 161 that sends the phosphor ink therein, a server 165 that stores the phosphor ink that has passed through the disperser 161,
2. A pressurizing pump 166 that pressurizes and supplies the phosphor ink to 2
Is provided.

As a result, the phosphor ink collected in the collection container 151 is re-dispersed by the disperser 161 and then discharged from the nozzle head 112 again. The disperser 1
In addition to this, an attritor, a jet mill, or the like can be used as 61. If the phosphor ink is manufactured and left for a long time, the dispersion state of the phosphor ink may be reduced. Further, when the phosphor ink is circulated by the circulation mechanism as in the second embodiment, the dispersion state of the phosphor ink may be reduced or secondary aggregates may be generated. Therefore, the nozzle may be clogged or the applied state of the applied phosphor ink to the groove 32 may be reduced. Problems are resolved.

The effect of such re-dispersion of the phosphor ink is not only obtained when the phosphor ink is re-dispersed in the ink circulation mechanism, but also in general, from the production of the phosphor ink to the application of the phosphor ink. It can also be applied when setting conditions.
Here, preferable conditions from the production of the phosphor ink to the application thereof will be described. FIG. 19 is a diagram showing a process from the production of the phosphor ink to the application thereof.

In producing the phosphor ink, the phosphor powder of each color, which is a raw material of the phosphor ink, a resin and a solvent are mixed and dispersed (primary dispersion). In this primary dispersion step, when dispersing with a disperser using a dispersing medium (media) such as a sand mill, a ball mill, or a bead mill, zirconia beads having a particle size of 1.0 mm or less are used as a medium, and a bead mill is used in a short time within 3 hours. It is preferable to carry out dispersion. This is to suppress damage to the phosphor powder and to suppress contamination (contamination) of impurities.

The viscosity of the phosphor ink is 15 to 20.
It is desirable to adjust to about 0 cp so that there is no large aggregate of about 以上 or more of the nozzle diameter. If the phosphor ink produced in this way is set and applied to the ink applicator immediately after production, the good dispersion obtained by the primary dispersion is maintained even during the application, so that the ink is not redispersed. Can be uniformly applied to each groove, and a good application state is relatively good. Then, in order to set the phosphor ink dispersing apparatus and the ink applicator in the same workplace immediately after production, the phosphor ink produced is set in the ink applicator as it is. It is considered good to apply.

In terms of time, it is preferable that the phosphor ink is applied within several hours, preferably within one hour, after the production of the phosphor ink. On the other hand, when the phosphor ink is applied and set in the ink applicator after a long period of time after the production of the phosphor ink, the dispersing state is reduced during the time since the coating is applied after a long time has passed since the primary dispersion. Secondary aggregates are easily formed. Therefore, if this is to be applied from the nozzle as it is, it is difficult to apply it uniformly to each groove, and clogging of the nozzle tends to occur.

However, even if the phosphor ink has been used for a long time since its manufacture (primary dispersion), if the phosphor ink is redispersed in the secondary dispersion step and then set and applied to an ink coating device, a good dispersion state is obtained. Therefore, it can be uniformly applied to each groove and clogging of the nozzle can be avoided. The secondary dispersion does not require a large shear force because the primary purpose is to disperse the secondary aggregates. Rather, stirring with a weak force causes less damage to the phosphor.

For this reason, it is effective to use zirconia beads having a particle diameter of 2 mm or less and to give a rotation speed of 500 rpm or less within 6 hours to perform redispersion. The reason for using zirconia beads is to avoid contamination as in the case of primary dispersion. As for the phosphor ink adjusted by the secondary dispersion in this way, the viscosity is set to about 15 to 200 cps in order to obtain stable ejection from the nozzle, and a large aggregate of about 1/2 or more of the nozzle diameter is formed. It is desirable not to do so.

[Modifications of First to Third Embodiments] In the above embodiment, an example was described in which the phosphor ink was directly applied to the groove between the partition walls. However, the reflection material ink was applied to the groove between the partition walls. Then, the present invention can be applied to a case where a phosphor layer is formed thereon. That is, the reflection layer and the phosphor layer 31 are formed by applying the reflection material ink and the phosphor ink using the above-described ink application device.

The reflecting material ink is a mixture of a reflecting material, a binder and a solvent component. As the reflecting material, a white powder having a high reflectance such as titanium oxide or alumina can be used. Titanium oxide having an average particle size of 5 μm or less is good. In the above embodiment, an AC-type PDP has been described as an example. However, the present invention is not limited to the AC-type PDP, but a PDP in which partitions are arranged in stripes and a phosphor layer is arranged between the partitions. Can be widely applied.

[0133]

[Example 1] A phosphor ink was prepared based on Embodiment 1 by changing the types and amounts of the phosphor particles, resin, and solvent, and the produced phosphor ink was applied to the PDP.
Was prepared.

[0134]

[Table 1]

[0135]

[Table 2]

[0136]

[Table 3]

[0137]

[Table 4]

Nos. In Tables 1, 2, and 3 Nos. 1 to 9 relate to Examples, and phosphor inks were prepared by dispersing with a sand mill using zirconia balls of 0.2 mm to 2 mm. Particle size of phosphor, kind and amount of resin, kind and amount of solvent, kind and amount of surfactant and dispersant, viscosity at the time of applying phosphor ink (shear rate at 25 ° C is 100 s
The viscosity at ec ^-1 ) and the like are as shown in Tables 1 to 3.

In manufacturing the PDP of the embodiment, the pitch of the partition walls 30 on the rear glass substrate 21 is 0.15 mm.
The height was set to 0.15 mm. The phosphor layer was formed by applying the phosphor ink of each color so as to fill up the top of each groove, and then baking at 500 ° C. for 10 minutes. The discharge gas to be charged is a neon (Ne) gas containing 10% xenon (Xe) gas, and the charging pressure is 500T.
orr.

On the other hand, the sample No. Sample Nos. 10 to 12 relate to comparative examples. In preparing the phosphor ink, in Sample No. 10, an acrylic resin and a dispersant (glyceryl triolate) were combined and blended.
In No. 11, ethyl cellulose having an ethoxy group content of 50% and terpineol were combined, but no dispersant was added. Further, the sample No. In No. 12, polyvinyl alcohol and water are combined, but no dispersant is contained. Other than that, the sample Nos. A PDP of a comparative example was manufactured in the same manner as in Examples 1 to 9.

Comparative test: For each of the produced PDPs, the state of adhesion of the phosphor to the side wall of the partition, the presence or absence of color mixing,
The panel brightness was measured. For the presence of color mixing, refer to PDP
Was emitted for each color, and the emission color was measured.

As a result, any of the PDs of the example and the comparative example
Also in P, the phosphor adhered to the upper part of the side wall of the partition wall, and no color mixing was observed. As for the panel luminance, the PDP was discharged at a sustaining voltage of 150 V and a frequency of 30 KHz.
, And measured with a panel luminance meter. The results are shown in Table 1.
As shown in FIGS. When the wavelength of ultraviolet light generated when these PDPs were driven was also examined, an excitation wavelength mainly by a molecular beam of Xe centered at 173 nm was observed.

Further, for each of the prepared phosphor inks,
An experiment was also performed in which nozzles were continuously discharged for a long time. As a result, all of the phosphor inks of the examples could be continuously ejected for 100 hours, but the phosphor ink of the comparative example clogged the nozzles within 8 hours. Consideration: As shown in Tables 1 to 4, regarding the luminance, the panel luminance of the example (No. 1 to 9) is 530 cd / m ² or more, and the panel luminance of the comparative example (No. 10 to 12). 460 to 480 cd / m ² ). This is because the PDP of the example is compared with the PDP of the comparative example,
It is considered that the ratio of the phosphor layer adhering to the side wall of the partition was larger than the bottom surface of the groove. [Example 2] In this example (sample Nos. 21 and 22),
Red (Y, Gd) BO ₃ : Eu, blue BaMgAl ₁₀ O ₁₇ :
A phosphor ink is used in which negatively charged oxide (SiO ₂ ) particles are adhered (coated) on the surfaces of phosphor particles of Eu and green ZnSiO ₄ : Mn.

[0144]

[Table 5]

The method of attaching SiO ₂ particles to the surface of the phosphor particles is as follows. First, a suspension of each color phosphor and a suspension of SiO ₂ particles (particle diameter is 1/10 or less of the phosphor particles) The two suspensions were mixed and stirred, suction-filtered, dried at 125 ° C. or higher, and fired at 350 ° C. Phosphor particles to which SiO ₂ particles are attached in this way, a resin component composed of ethyl cellulose,
A mixed solvent of terpineol and pentanediol (1/1)
1) was mixed at a ratio shown in Table 5 and mixed and dispersed by a jet mill to prepare a phosphor ink. When mixing and dispersing,
The pressure applied to the mixed solution is 10 kgf / cm ^{2 to} 200 K
It was adjusted to the range of gf / cm ² .

[0146] The phosphor ink thus produced was used in Table 5
And the other conditions were the same as in Example 1 to produce a PDP. In the same manner as in Example 1 above, the state of the phosphor adhered to the side wall of the partition, the presence or absence of color mixture, and the panel luminance of the produced PDP were measured. As a result, in each case, the phosphor adhered to the upper portion of the partition wall, and no color mixing occurred.

The panel luminance was good as shown in Table 5. Further, the sample No. In any of the phosphor inks 21 and 22, nozzle clogging did not occur even after continuous application for 100 hours or more.

[0148]

Embodiment 3 In this embodiment, various surfactants are added to the phosphor ink as a dispersant and a charge removing substance (Sample Nos. 31 to 37), and conductive fine particles are added as a charge removing substance. Examples (Sample Nos. 38 to 42) are shown. Further, among them, the sample No. 31 to 34 are also examples in which oxides such as ZnO and MgO are attached to the surface of the phosphor.

The sample No. Reference numeral 43 denotes an example in which a charge removing substance is not added.

[0150]

[Table 6]

[0151]

[Table 7]

[0152]

[Table 8]

[0153]

[Table 9]

The type, particle size and amount of the phosphor of the phosphor ink used in each embodiment, the type and amount of the oxidizing agent attached to the phosphor, the type and amount of the resin, the type and amount of the solvent, etc. It is as shown in Tables 6 and 7. In addition, the types and amounts of the surfactant and the charge removing substance, and the viscosity (25
Shear rate at ℃ is for viscosity) at 100 sec ^-1, it is shown in Table 8,9. Then, using a nozzle having a nozzle diameter of 50 μm, the phosphor ink was applied by discharging the phosphor ink while scanning while keeping the distance between the nozzle tip and the rear glass substrate at 1 mm, and the other conditions were the same as those in Example 1. PDP was produced.

In this embodiment, in order to improve the wetting of the surface to which the phosphor ink is applied, the surface of the rear glass substrate with the partition walls is coated with an excimer lamp (center wavelength: 172 nm) before applying the phosphor ink. Irradiate for seconds to 1 minute,
In order to remove the binder and the residue remaining in the phosphor layer even after the phosphor layer is fired, the surface of the rear glass substrate on which the phosphor layer is formed is coated with an excimer lamp (center wavelength 172n).
m) for 10 seconds to 1 minute.

With respect to each of the produced PDPs, the panel luminance when the PDPs were driven and the occurrence of streaking were also measured. As for the panel brightness, the PDP was maintained at a discharge maintaining voltage of 15
It was driven at a frequency of 0 V and 30 KHz and measured with a panel luminance meter. Regarding streak irregularities, the entire PDP screen was displayed in white, and the presence or absence of streak irregularities was visually observed.

When the wavelength of ultraviolet rays generated when these PDPs were driven was also examined, an excitation wavelength mainly by a molecular beam of Xe centered at 173 nm was observed. These results are shown in Tables 8 and 9. As shown in Tables 8 and 9, sample no. 31 to 42
Sample No. As compared with the luminance of 43, a higher luminance is obtained. Further, the sample No. In Sample No. 43, although line unevenness occurred, Sample No. In Nos. 31 to 42, there was no occurrence of uneven muscle.

When the phosphor layers of each of the produced PDPs were observed, no color mixing of the phosphors was observed in any of the PDPs. 43
Sample No. than 31 to 42 showed better adhesion of the phosphor to the side surface of the partition wall. Consideration: The test results for such luminance and uneven stripes are shown in Sample No. 1 in which a neutralizing substance was added to the phosphor ink. 31
Sample Nos. To 42 in which no charge removing substance was added to the phosphor ink were used. Rather than 43, it is considered that the phosphor ink was generated because the phosphor ink was uniformly applied on the partition wall side surface and the groove bottom surface in a well-balanced manner.

[0159]

[Embodiment 4] [Example relating to primary dispersion] Embodiment 3
As shown in Table 10, the dispersion method (type of beads, particle size, and dispersion time) during ink production (primary dispersion) was varied in various ways to produce phosphor inks of each color.

[0160]

[Table 10]

In each phosphor ink, 60 wt% of each color phosphor powder having an average particle size of 3 μm and 1 wt% of ethyl cellulose were used.
%, And a mixed solvent of terpineol and limonene was used as a solvent. Then, for the produced phosphor ink, the luminance was evaluated, the particle size of the phosphor powder was measured (the particle size of the phosphor after primary dispersion), and the presence or absence of aggregates was evaluated.

In the evaluation of the luminance, the phosphor ink after dispersion was fired in air at 500 ° C. to form a phosphor layer, which was placed in a vacuum chamber and irradiated with vacuum ultraviolet light by an excimer lamp. The excitation light emitted at that time was measured with a luminance meter. Each evaluation result is as shown in Table 10. From the evaluation results in Table 10, it can be seen that, for each of the red, green, and blue colors, the brightness is lower when glass beads are used as the dispersion medium than when zirconia beads are used. In the case of using glass beads as a dispersion medium, a large amount of sodium (Na), calcium (Ca), and silicon (Si) components are detected.

As described above, the reason that the brightness is lower when glass beads are used as the dispersion medium is that a strong impact is applied to the glass beads when a shear force is applied at the time of dispersion, so that the glass component is contaminated. ) Is considered to be mixed into the ink as a light emission killer. Also, from the evaluation results in Table 10, it can be seen that even when the type of dispersion medium used is the same, the luminance changes if the particle size or the dispersion time changes. This is presumably because, even when the same shearing force is applied, the collision coefficient is different when the particle size of the dispersion medium is different, and the number of collisions with the phosphor powder is different when the dispersion time is different.

Further, from the results shown in Table 10, the phosphor particle size after dispersion is smaller than that before dispersion. This indicates that the phosphor powder is pulverized by dispersion or the interface state is deteriorated. [Examples Regarding Secondary Dispersion] Next, each of the prepared phosphor inks was allowed to stand for 72 hours after temporary dispersion, and then subjected to secondary dispersion. As shown in Table 11, the secondary dispersion was carried out by changing the particle size and dispersion time of zirconia beads as a dispersion medium.

[0165]

[Table 11]

Then, for each phosphor ink after the secondary dispersion, the luminance was evaluated, the particle size of the phosphor powder was measured (the particle size of the phosphor was measured after the primary dispersion), and the presence or absence of aggregates was evaluated. Each evaluation result is as shown in Table 11. As is clear from Table 11, when the dispersion time in the secondary dispersion is less than 1 hour, aggregates remain in the phosphor ink for each of the red, green, and blue colors. Is no longer seen. Further, even when the dispersion time is lengthened, no change is observed in the particle size of the phosphor particles.

From the results, it can be seen that the secondary dispersion using zirconia as a dispersion medium can disperse aggregates without crushing the phosphor particles themselves. Also, from Table 11, it can be seen that even if the dispersion time is lengthened, no decrease in luminance is observed. This shows that the secondary dispersion using zirconia as the dispersion medium can perform dispersion with little damage to the phosphor surface.

[0168]

As described above, according to the present invention,
When the phosphor ink is applied by continuously scanning along the grooves between the partitions arranged on the plate while continuously discharging the phosphor ink from the nozzles, based on the positional information on each groove, By adjusting the position in the groove through which the nozzle passes, even when the groove is curved, it is possible to scan so that the nozzle always passes through the center of the groove, so that each groove can be scanned. The phosphor ink can be uniformly applied, and can be adhered to the bottom of each groove and the side wall of the partition wall in a well-balanced manner.

Further, while the phosphor ink is applied by continuously scanning along the grooves between the partition walls provided on the plate while continuously discharging the phosphor ink from the nozzles, when the phosphor ink is applied, The width was measured in the longitudinal direction of the groove, and the phosphor ink was ejected from the nozzle while adjusting the amount of the phosphor ink applied per partition length according to the measured groove width. Thus, the phosphor ink can be uniformly applied even when the groove width varies or the width varies in the groove.

Further, when the phosphor ink is sequentially applied to the plurality of grooves, the phosphor ink is applied while maintaining the state of continuously discharging the phosphor ink from the nozzles even when the nozzle is at a position off the groove. By doing so, it is possible to prevent the phosphor ink from adhering near the nozzle outlet, so that a stable ink jet flow can be obtained.
The phosphor ink can be uniformly applied to the plurality of grooves.

Further, by dispersing the phosphor ink with a disperser before the phosphor ink is continuously discharged from the nozzle, the dispersibility of the phosphor ink to be applied is improved. It can be adhered to the bottom in each groove and the side wall of the partition wall in good balance. Further, in the phosphor ink used in the production of PDP, the average particle size is 0.5 to 5%.
μm phosphor powder, a mixed solvent of OH-terminated terpineol, butyl carbitol acetate, butyl carbitol, pentanediol, limonene, etc. as a solvent, and an ethoxy group (—OC) in a cellulose molecule as a binder. _The phosphor ink filled in the grooves between the partition walls can also be applied to the side walls of the partition walls by using ethyl cellulose or ethylene oxide polymer having a content of ₂ H ₅ ) of 49% or more and further adding a dispersant. The phosphor ink can adhere to the bottom in each groove and the side wall of the partition wall in a well-balanced manner.

In such a phosphor ink,
By adding a static elimination substance, PDP with a fine structure
In this case, the phosphor ink can be evenly applied to the grooves between the partition walls, and there is almost no occurrence of stripe unevenness when the completed PDP is driven.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an AC surface discharge type PDP according to an embodiment.

FIG. 2 is a configuration diagram of a display device in which a circuit block is mounted on the PDP.

FIG. 3 is a schematic configuration diagram of an ink application device according to the first embodiment.

FIG. 4 is a diagram schematically illustrating image data obtained by groove position detection of the ink application device according to the first exemplary embodiment;

5 is a partially enlarged view of FIG. 4 and a graph schematically showing luminance at each position on a search line L1.

FIG. 6 is an example of a partially enlarged view of FIG. 4;

FIG. 7 is a diagram showing a coating state when a nozzle is displaced from a center portion of a groove, and a state of a formed phosphor layer.

FIG. 8 is a view schematically showing a state in which a phosphor layer is formed after a phosphor ink is applied to a groove.

FIG. 9 is a diagram schematically showing the relationship between the concentration of a resin binder in a phosphor ink and the shape of a phosphor layer to be formed.

FIG. 10 is a graph comparing the viscosities of the phosphor ink according to the present invention and inks used in conventional screen printing and the like.

FIG. 11 is a diagram showing a state of discharge of phosphor ink from a nozzle.

FIG. 12 is a perspective view showing an ink application device according to a second embodiment.

FIG. 13 is a front view (partial cross section) of the ink application device.

FIG. 14 is an enlarged view of the nozzle head unit shown in FIG.

FIG. 15 is a view showing a state where a nozzle head is scanned on a rear glass substrate in the ink application device.

FIG. 16 is an example of a partially enlarged view of image data obtained by groove position detection of the ink application device.

FIG. 17 is a diagram showing a modification of the second embodiment.

FIG. 18 is a diagram illustrating a configuration of a phosphor ink circulation mechanism in the ink application device according to the third embodiment.

FIG. 19 is a diagram showing a process from the production of the phosphor ink to the application thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Front panel 20 Back panel 21 Back glass substrate 30 Partition wall 31 Phosphor layer 32 Groove 33 Auxiliary partition wall 50 Ink coating device 51 Ink server 52 Pressure pump 53 Nozzle head 54 Nozzle 55 Groove detection head 56 Substrate mounting table 100 Main body 101 Main body base 103 Substrate mounting table 110 Nozzle head unit 112 Nozzle head 112a Rotating shaft 113 Nozzle 115 Rotation drive mechanism 116 Jet shielding mechanism 120 Imaging unit 150 Circulation mechanism 151 Collection container 152 Pressure pump 154 Ink replenisher 160 Circulation mechanism 161 Disperser 164 Circulation pump

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B41M 5/00 B41M 5/00 E 5C040 C09D 11/00 C09D 11/00 C09K 11/02 C09K 11/02 Z 11/08 11/08 G H01J 11/02 H01J 11/02 B (31) Priority claim number Japanese Patent Application No. 10-287645 (32) Priority date October 9, 1998 (Oct. 1998) (33) ) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 11-17855 (32) Priority date January 27, 1999 (Jan. 27,1999) (33) Priority claiming country Japan ( JP) (31) Priority claim number Japanese Patent Application No. 11-88717 (32) Priority date March 30, 1999 (1999.3.30) (33) Priority claiming country Japan (JP) (72) Inventor Masaki Aoki 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Ka Miyashita 1006 Kadoma Kadoma, Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Keisuke Sumita 1006 Kadoma, Kadoma, Kadoma, Osaka Pref. Address F-term (reference) in Matsushita Electric Industrial Co., Ltd. AE07 BA03 BA04 BA06 BA13 BC07 BC12 BC20 BC27 BC33 BE01 BE12 BE22 BE23 CA06 DA03 EA28 EA41 EA44 EA46 GA10 GA24 5C028 FF06 FF16 5C040 FA01 GG09 JA12 JA13 MA02 MA03 MA23 MA24

Claims (4)

[Claims] 1. A phosphor ink applying step of applying phosphor ink to a groove between a partition and a partition on a first plate on which the partition is arranged in a stripe shape; A sealing step of overlaying and sealing the second plate on the arranged side and enclosing a gas medium, and in the phosphor ink applying step, an oxide having a positive or negative charge property is disposed on the surface. The plasma ink is applied by relatively scanning the nozzle along the groove between the partition walls while discharging the phosphor ink containing the phosphor particles from the nozzle in a continuous flow. Display panel manufacturing method. 2. The phosphor ink used in the phosphor layer forming step is produced by dispersing a mixture of phosphor particles, a binder, a solvent, and a charge removing substance with a disperser, and at 25 ° C. 2. The method according to claim ^1, wherein the viscosity at a shear rate of 100 sec ^-1 is 10 to 1000 centipoise. 3. A phosphor ink which is used for forming a phosphor layer of a plasma display panel and is discharged from a nozzle which scans along a partition of a plate in which the partitions are arranged in a stripe pattern. A phosphor ink comprising a mixture of a phosphor particle having a surface on which an oxide having a charging property is arranged, a binder, and a solvent. 4. A phosphor ink which is used for forming a phosphor layer of a plasma display panel and is discharged from a nozzle which scans along a partition of a plate having a partition arranged in a stripe shape. A phosphor ink comprising a mixture of a phosphor particle having a surface on which an oxide having a charging property is arranged, a binder, and a solvent.