JP3432151B2 - Method and apparatus for forming ribs on back plate of plasma display panel - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to rib formation of a plasma display panel rear plate which can efficiently produce a plasma display panel rear plate which is a constituent unit of a plasma display panel as an image display device. A method and apparatus.

[0002]

2. Description of the Related Art Plasma display panels (PD
P) is a flat panel, because it is larger, thinner, lighter, and capable of displaying high-definition images than CRTs.
Among displays (FPD), it has been attracting attention as a display for the next generation.

The constituent units of the PDP can be roughly classified into a front plate and a rear plate . In the cell structure diagram of the AC type color PDP of FIG. 9 , 1 is a front plate and 10 is a back plate. The front plate 1 is provided with a dielectric layer 5 and a protective layer 6 behind a front glass plate 2 with a common electrode 3 and a scanning electrode 4 interposed therebetween. The rear plate 10 has address electrodes 12 and a dielectric layer 13 on the front side of a rear glass substrate 11, and ribs (partitions) 14 are formed on the front surface of the dielectric layer 13 so as to partition the address electrodes 12. . Fluorescent substance R between the ribs 14
(Red), phosphor G (green) and phosphor B (blue) are provided. The top of the rib 14 is in contact with the protective layer 6.

The manufacturing process includes a front plate used mainly in thin film technology and photolithography technology used in semiconductor manufacturing technology, and a back plate manufactured by combining thin film / photolithography technology with thick film technology. It can be classified as a face plate.

In the situation where the PDP is further increased in size and the pattern is made finer, various manufacturing methods for forming the ribs of the back plate have been proposed including the screen printing method described below. However, at present, it is becoming particularly difficult to meet the required pattern accuracy.

(1) Screen printing method A schematic view of a rib forming method by the screen printing method is shown in FIG.
Shown in. In the figure, 80 is a screen, 81 is a screen frame with a screen, and 82 is a squeegee, and a rib paste that solidifies to form the ribs 14 is applied to the rear glass substrate 11 as a material to be printed through the screen 80.

Rib formation by the screen printing method is a method of transferring the rib paste, which has passed through the screen 80 patterned in a rib shape, to the rear glass substrate 11 of the PDP rear plate, and film formation and patterning can be performed simultaneously. As a feature, the waste of paste is small and the manufacturing cost can be reduced relatively easily.

However, the screen printing method has the following problems.

In order to form the required rib height of 150 μm, it is necessary to carry out laminated printing 10 to 15 times, and it is necessary to repeatedly perform printing and drying, which leads to a long lead time.

It is necessary to repeat the alignment between the printing position and the rear glass substrate 11 for each layered printing, and the repetition error of this alignment greatly affects the deterioration of the rib pattern accuracy.

In screen printing, a clearance is required between the screen and the substrate in order to improve the plate separation during printing, the screen is stretched by a squeegee during printing, and the screen is distorted. As a result, the rib pattern accuracy is improved. Getting worse.

The screen is made by adhering a mesh made of stainless steel or polyester to the screen frame with high tension, and when stretched by a squeegee every time the screen is printed, the tension is lowered and the rib pattern is plastically deformed. This decrease in tension and plastic deformation are also major factors that reduce pattern accuracy and reproducibility. This is the fundamental problem of the screen printing method.

When the PDP becomes large and the pattern area becomes proportionally large, it is necessary in principle to increase the screen clearance, and further, the screen distortion becomes large and the pattern accuracy tends to deteriorate.
This is also a fundamental problem of the screen printing method.

In the screen printing method, it is customary to use a screen frame which is 4 to 6 times as large as the pattern effective area. When the PDP becomes larger, the screen frame size becomes larger, and the screen printing is inevitable. The device becomes large, which leads to an increase in manufacturing cost.

(2) Sandblast method FIG . 11 is a schematic diagram of a rib forming method by the sandblast method .
Shown in. In this sandblasting method, as shown in FIG. 7A, the screen printing lamination is repeated by solid printing up to the required rib height over the entire pattern effective area of the rear glass substrate 11 on the PDP back plate, or the rib height is set in advance. The formed rib sheet is attached to the rear glass substrate 11 to form the rib material 8
5 is formed on the substrate, a photoresist 86 is then attached to the surface of the rib material 85, a mask 87 having a required pattern is overlaid as shown in FIG. 6B, and the photoresist 86 is exposed to ultraviolet rays (UV exposure). After developing as shown in FIG.
As shown in FIG. 8D, the photoresist 86 remaining after development is used as a mask, and only unnecessary portions as ribs are removed by sandblasting with an abrasive spray, patterned, and resist stripping treatment is performed as shown in FIG. This is a method of forming the ribs 14 of a required pattern by performing.

However, the sandblast method has the following problems.

It is difficult to determine the patterning end point and the stability is poor.

The proportion of unnecessary rib material is large, and the utilization rate of the rib material is poor.

Since the abrasive is sprayed, the cleanliness is poor and the substrate needs to be cleaned.

(3) Lift-off method A schematic view of a rib forming method by the lift-off method is shown in FIG . This lift-off method is performed by the photoresist 90 until the rib height required for the PDP back plate is reached as shown in FIG.
Laminate it on the back glass substrate 11 by sticking it several times.
The photoresist 90 is laminated, and a mask 93 having a required pattern is overlaid as shown in FIG. 7B, and the photoresist 90 is collectively exposed with UV light (UV exposure), and developed as shown in FIG. Only the resist 90 part is left, and the same figure (D)
A rib paste 92 as a rib material is embedded in the groove 91 from which the photoresist has been removed as shown in the above, and after dry curing and surface polishing, the photoresist is peeled off using a stripping solution as shown in FIG. Is the way to do it.

However, the lift-off method has the following problems.

Photoresist 9 thickened by bonding
In principle, it is difficult to expose 0 at a time to perform high aspect (resist thickness / line width) patterning.

The adhesion of the rib material to the substrate 11 is poor.

It is difficult to improve the solvent resistance and alkali resistance of the rib material against the photoresist stripping solution.

(4) Photopaste method A schematic view of a rib forming method by the photopaste method is shown in FIG.
Shown in. The photo paste method is characterized in that the rib paste or the rib sheet itself is provided with photosensitivity. First, as shown in FIG. 7A, a rib paste is solidly printed or a rib sheet is attached to form a photosensitive rib material 95 on the rear glass substrate 11, and then a mask 96 having a required pattern is formed as shown in FIG. Are exposed to ultraviolet light (UV exposure) to form a rib pattern, a photosensitive rib material 95 is laminated thereon as shown in FIG. 6C, and a mask 96 is overlapped as shown in FIG. To expose. After that, the photosensitive rib material laminate shown in FIG. 6C and the ultraviolet exposure shown in FIG.
Unnecessary portions are removed by the development shown in FIG. 6E to obtain the ribs 14 having a required pattern.

However, unlike the general non-filler photoresist, the rib photo paste needs to have a high filler content, and the higher the filler content, the worse the light transmission. In principle, it is difficult to combine a paste containing a large amount of a filler with a highly photosensitive paste, and patterning with a film thickness of about 50 μm is the limit for one exposure.

Other problems of the photopaste method are as follows.

It is necessary to repeat the film forming / exposure / phenomenon of the photo paste several times, and the pattern accuracy deteriorates due to the alignment error.

Photo paste is more expensive than rib paste of other methods.

A large amount of rib material waste is generated by the development, and the material utilization rate is poor.

In order to maintain photosensitivity, there are many restrictions on the filler that can be used in the paste.

[0032]

The technical elements required for the rib forming method of the PDP back plate are as follows.

(1) Easy to realize high precision and high definition on a large screen The PDP has a large screen diagonal of 20, 40, and 50 inches, and the display resolution has been improved to SVGA, XGA, HDTV. Are requested at the same time. Under these circumstances, the rib forming method for the back plate also needs to be large-sized, high-precision, and narrow in pitch. However, under the present circumstances, it is difficult for the conventional methods to easily meet these demands. In addition, the rib cross-sectional shape has a high aspect ratio (height / width).
That also makes it difficult to respond.

(2) It is possible to process the optimum cross-sectional shape. The color PDP is ribbed R (red) G (green) B
The (blue) three-color phosphor is a display that utilizes the property of emitting light by ultraviolet rays, and various measures are being studied, including improvement of the phosphor itself, in order to improve the display contrast as a display. . As one of the measures, the cell shape for the phosphor to efficiently emit light is also an important factor, and the rib cross-sectional shape directly influences the shape of the phosphor emission surface. It is desirable to have a method capable of forming an optimum shape.

However, the conventional method can deal only with the rectangular rib cross-sectional shape, and the luminous efficiency of the phosphor cannot be optimized.

(3) The manufacturing method is simple, and molding can be performed quickly and inexpensively. In the rib forming method according to the conventional technique, it is necessary to repeat the same treatment a plurality of times, and it goes without saying that the lead time until completion is long, and the cost is increased. Also leads to Further, repeating the alignment for each process is a major factor that deteriorates the rib pattern accuracy due to the alignment error.

Further, in the lift-off method and the photo paste method, a large amount of expensive materials such as photoresist and photo paste are used, and at the same time, a large amount of waste is also generated, so that it is difficult to effectively use the materials and the cost is increased. Connect In addition, a large number of expensive devices such as a large-scale exposure / development / etching device are required, which also increases the cost.

In view of the above points, the present invention provides a method and an apparatus for forming ribs on a rear panel of a plasma display panel, which can collectively form ribs on the rear panel of the plasma display panel with high mass productivity. The purpose is to

Other objects and novel features of the present invention will be clarified in the embodiments described later.

[0040]

In order to achieve the above object, the invention of claim 1 of the present application provides a rib forming method for a back plate of a plasma display panel, wherein a plurality of ribs are formed on a back substrate. Transfer roll having grooves corresponding to the ribs and rotating and moving on the back substrate
And the rib material is forcedly pushed into the groove and injected.
A rib material supply nozzle having a mouth and a margin on the transfer roll.
Removing the partial rib material using the scraper facing integer, the
While pouring the rib material into the groove from the rib material supply nozzle ,
Excessive rib material is removed by a scraper and the transfer roll is rotationally moved while the surface is adjusted to transfer the rib material injected into the groove onto the rear substrate to remove the plurality of ribs. The feature is that they are formed simultaneously.

[0041]

The invention of claim 2 is, in the rib formation method of a plasma display panel back plate of claim 1, is characterized by applying an organic binder on the rear substrate before transfer of the rib material.

According to a third aspect of the present invention, in a rib forming apparatus for a rear plate of a plasma display panel, which forms a plurality of ribs on a back substrate, a transfer roll having grooves corresponding to the plurality of ribs, and the groove A rib material supply nozzle having a discharge port for forcibly pushing out and injecting the rib material, a scraper for removing and aligning excess rib material on the transfer roll, and the transfer roll rotationally moving on the back substrate. It is characterized in that it is provided with a roll driving means that is driven as described above.

[0044]

[0045]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a rib forming method and apparatus for a back plate of a plasma display panel according to the present invention will be described below with reference to the drawings.

1 to 7, the first embodiment of the present invention (rib formation by the upper surface roll transfer method) is an AC type PDP.
A case where a stripe rib pattern is formed on the back plate will be described. First, as shown in FIGS. 1 (A), 2 (A) and 3, in order to improve the transferability and adhesion of the rear glass substrate 11 and the rib material 20 to the rear glass substrate 11 of the PDP rear plate. Then, the organic binder 21 is applied to almost the entire rear glass substrate 11 in advance.

Next, as shown in FIGS. 1 (B), 2 (B) and 4, a cross section equal to the PDP rib pattern effective area width, parallel to the outer circumference of the cylindrical roll surface, and in conformity with the rib cross-sectional shape. Rib transfer roll 3 having grooves 31 at desired equal intervals
0, a rib material supply nozzle 40 as a rib material supply means for injecting the rib material 20 into the groove 31, and a rib material supply unit 5
0 and 0, while the transfer roll 30 is rotated in contact with the rear glass substrate 11, the transfer roll 3 is rotated as shown in FIG.
The rib material 20 is forcibly injected from the rib material supply nozzle 40 into the groove 31 of 0, the excess rib material on the roll is removed by the scraper 45, and the surface is smoothed. Then, the transfer roll 30 and the rear glass substrate 11 are brought into contact with each other. Then, the rib material 20 in the transfer roll groove is transferred onto the rear glass substrate.

Then, on the upper surface of the rear glass substrate 11, the rib transfer roll 30 is rotationally moved in the required direction in a straight-ahead direction (in other words, is moved in parallel while rotating the roll shaft). As shown in FIG. 5, the ribs 14 are collectively molded (simultaneously molded) on the rear glass substrate 11. After molding, the rear glass substrate 11 is dried and fired to complete the ribs 14, and a required stripe rib pattern of the AC-type PDP back plate in which a large number of ribs 14 are arranged in parallel is obtained.

The organic binder 21 is thermally decomposed by drying and baking the rear glass substrate 11 after transfer, and the rib 14 is completed. As a method for applying the organic binder 21, a general method such as a roll coating method used for resist coating or a direct coating method can be used.

Further, the rib material 20 contains glass powder as a main component, contains an organic binder and an organic solvent, is viscous like viscosity and can retain its shape after transfer,
It is a material that becomes an insulating sintered body after firing in a later step.

Further, as shown in FIG. 2B, the rib material supply nozzle 40 and the rib material supply unit 50 are connected by a pipe 51, and the rib material supply unit 50 has a built-in screw 52 for pressurization to supply the rib material. The rib material 20 is pressurized from the unit 50 to the rib material supply nozzle 40 and forcedly delivered. As a result, the rib material 20 is forcibly pushed out and injected into the groove 31 on the transfer roll 30 side from the slit-shaped ejection port 41 of the rib material supply nozzle 40.

As shown in FIG. 6, the rib transfer roll 30 is
An integrally machined transfer roll composed of a die in which a groove 31 having a rib-shaped cross section is collectively machined on the outer peripheral portion of a cylindrical roll, or a shape corresponding to one pitch of the rib in FIG. It is also possible to use a split processing transfer roll composed of a die in which the above-mentioned products 32 are combined, or a roll in which only the outer peripheral portion of the roll is made of a fluororesin and a rib groove is processed in the resin portion. If the roll surface material is metallic,
It is also possible to apply a surface treatment such as plating or fluorine to impart releasability when the rib material is separated from the transfer roll 30.

According to the first embodiment, the following effects can be obtained.

(1) High-definition P, such as the cross-sectional shape of the rib 14, the pitch of the rib, the linearity of the rib, the accuracy of the entire pattern, etc.
The accuracy of the groove 31 of the transfer roll 30, which is required to manufacture the DP with high accuracy, is directly determined by the machining accuracy, and can be processed with high accuracy.
Can be formed with high precision. In addition, the rib forming method of the present embodiment can realize rib formation with extremely high reproducibility.

(2) In the conventional method, ribs are completed by repeatedly forming rib constituent elements patterned in the same shape a plurality of times. Therefore, the completed rib cross-sectional shape is always rectangular. The rectangular shape of the rib is a disadvantageous shape in order to allow the fluorescent substance between the ribs to emit light efficiently.

However, in the rib formation of the present embodiment, the rib shape for efficiently emitting light from the phosphor can be easily developed as the groove processing shape of the transfer roll, and the degree of freedom of the rib cross-sectional shape is increased. A PDP with high luminous efficiency can be realized.

(3) In this embodiment, unlike the method of completing the rib by repeating the same process of the conventional technique, the rib material 20 is transferred to the rear glass substrate to collectively form the simultaneous rib pattern (simultaneous forming). ) Is possible, and significant productivity improvement and cost reduction can be realized.

FIG. 8 shows a second embodiment of the present invention (rib formation by a lower surface roll transfer method). In this case, after applying the organic binder 21 to the lower surface of the rear glass substrate 11, the rib material 20 is transferred to the lower surface of the rear glass substrate 11 by the rib transfer roll 30 to form the ribs 14. The first described above except that the lower surface of the rear glass substrate 11 is transferred.
This is the same as the embodiment.

In the case of the second embodiment, the rib material 20 is used.
Depending on the physical properties (viscosity, etc.) of the rib material, the shape stability of the rib material after transfer can be improved.

In any of the first and second embodiments, the rib material 20 can be directly transferred to the rear glass substrate 11, but the transferability of the rear glass substrate 11 and the rib material 20 and In order to improve the adhesion, it is effective to apply the organic binder 21 to the rear glass substrate 11 in advance as shown in each embodiment.

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

In the first and second embodiments, the roll driving means for bringing the rib transfer roll 30 into contact with the rear glass substrate and linearly moving it while rotating it, for example, presses the transfer roll against the glass substrate. This can be realized by a spring member and a mechanism such as an air cylinder for axially supporting the transfer roll and rotating it linearly on the substrate.

[0077]

[0078]

Further, the rib material supply unit 50 which pressurizes and supplies the rib material 20 to the nozzle 40 has a structure of mechanically pressurizing with a screw, a pump or the like, and also pressurizes and supplies with gas or the like in the closed container. The configuration etc. are possible.

Transfer to the rear glass substrate 11
Movement of the roll 30 may be any relative movement, transfer
It is obvious that the present invention also includes a configuration in which the rear glass substrate 11 is moved without changing the position of the roll 30 .

Although the embodiment of the present invention has been described above, it is obvious to those skilled in the art that the present invention is not limited to this and various modifications and changes can be made within the scope of the claims. Ah

[0082]

As described above, according to the present invention,
The following effects can be achieved.

(1) High precision, high precision, high reproducibility The present invention produces a high precision PDP with high precision such as rib cross-sectional shape, rib arrangement pitch, rib linearity, and overall pattern precision. required for the accuracy of the groove of the transfer roller is determined to thus directly machining accuracy, can be processed with high accuracy, it is possible to form eventually the ribs with high accuracy, further Rib formation can be realized with extremely high reproducibility.

(2) Improvement of luminous efficiency In the conventional method, ribs are completed by repeatedly forming rib constituent elements patterned in the same shape a plurality of times. Therefore, the completed rib cross-sectional shape is always rectangular. The rectangular shape of the rib is a disadvantageous shape in order to allow the fluorescent substance between the ribs to emit light efficiently.
However, according to the present invention, the rib shape for efficiently emitting light from the phosphor can be easily developed as the groove processing shape of the transfer roll, the degree of freedom of the rib cross-sectional shape is increased, and as a result, a PDP having high light emission efficiency is obtained. realizable.

(3) Improving productivity by collective processing Unlike the method of completing ribs by repeating the same process of the prior art, the present invention collectively molds the entire rib pattern when a rib material having appropriate physical properties is selected. It is possible to realize significant productivity improvement and cost reduction.

[Brief description of drawings]

FIG. 1 is a schematic front view illustrating a first embodiment of the present invention.

FIG. 2 is a schematic side cross-sectional view illustrating the first embodiment.

FIG. 3 is a perspective view showing an organic binder coating step in the first embodiment.

FIG. 4 is a perspective view showing an upper surface roll transfer step in the first embodiment.

FIG. 5 is a perspective view showing a rib completed state according to the first embodiment.

FIG. 6 is a perspective view of an integrally processed transfer roll that can be used in the first embodiment.

FIG. 7 is a perspective view of a divided work transfer roll that can be used in the first embodiment.

FIG. 8 is a schematic side sectional view illustrating a second embodiment of the present invention.

FIG. 9 is a perspective view showing an AC type color PDP cell structure.
It

FIG. 10 illustrates rib formation by a conventional screen printing method.
It is a schematic diagram which shows.

FIG. 11 illustrates rib formation by a conventional sandblast method .
It is a schematic diagram which shows.

FIG. 12 illustrates rib formation by a conventional lift-off method.
FIG.

FIG. 13: Rib formation by conventional photo paste printing method
It is a schematic diagram explaining.

[Explanation of symbols]

1 Front plate 10 Back plate 11 Rear glass substrate 12 ribs 20 rib material 21 Organic Binder 30 Rib transfer roll 31 groove 40 Rib material supply nozzle 50 rib material supply unit

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Claims (3)

(57) [Claims] 1. A method for forming ribs on a rear plate of a plasma display panel, comprising a plurality of ribs formed on a rear substrate, the transfer roll having grooves corresponding to the plurality of ribs and rotating and moving on the rear substrate. Using a rib material supply nozzle having a discharge port for forcibly extruding and injecting a rib material into the groove, and a scraper for removing and aligning excess rib material on the transfer roll, from the rib material supply nozzle While pouring the rib material into the groove, removing excess rib material with the scraper and rotating the transfer roll while aligning the surface, the rib material injected into the groove is transferred onto the back substrate. Forming a plurality of ribs at the same time by a method for forming ribs on a rear plate of a plasma display panel. 2. The method of forming ribs on a back plate of a plasma display panel according to claim 1 , wherein an organic binder is applied to the back substrate before transferring the rib material. 3. A rib forming apparatus for forming a plurality of ribs on a rear substrate for a plasma display panel back plate, comprising: a transfer roll having grooves corresponding to the plurality of ribs; and a rib material forced into the grooves. A rib material supply nozzle having a discharge port for extruding and injecting, a scraper for removing and aligning excess rib material on the transfer roll, and a roll for driving the transfer roll to rotate on the back substrate. A rib forming device for a back plate of a plasma display panel, comprising: a driving means.