JP4029599B2 - Display device manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a display device such as a liquid crystal display or a plasma display panel.
[0002]
[Prior art]
In recent years, plasma display panels have attracted attention as thin display devices with excellent visibility, and higher definition and larger screens are being promoted.
[0003]
This plasma display panel is roughly classified into an AC type and a DC type in terms of driving, and there are two types of discharge types, a surface discharge type and a counter discharge type, but high definition, large screen, and simple manufacturing. Therefore, at present, AC-type and surface-discharge-type plasma display devices have become the mainstream in the industry.
[0004]
An example of the panel structure in this AC type plasma display device is shown in FIG. As shown in FIG. 4, a plurality of pairs of striped display electrodes 4 are formed on a transparent front substrate 1 such as a glass substrate, and a pair of scanning electrodes 2 and sustain electrodes 3 is formed on the substrate 1. A light shielding layer 5 is disposed between adjacent display electrodes 4. The scan electrode 2 and the sustain electrode 3 are respectively composed of transparent electrodes 2a and 3a and bus electrodes 2b and 3b made of silver or the like electrically connected to the transparent electrodes 2a and 3a. A dielectric layer 6 is formed on the front substrate 1 so as to cover the plurality of pairs of electrodes, and a protective film 7 is formed on the dielectric layer 6.
[0005]
A plurality of stripes covered with an insulator layer 9 are arranged on the rear substrate 8 opposed to the front substrate 1 in a direction perpendicular to the display electrodes 4 of the scan electrodes 2 and the sustain electrodes 3. A data electrode 10 is formed. On the insulator layer 9 between the data electrodes 10, a plurality of stripe-shaped partition walls 11 are arranged in parallel with the data electrode 10, and the phosphor layer 12 is formed on the side surface 11 a between the partition walls 11 and the surface of the insulator layer 9. Is provided.
[0006]
The substrate 1 and the substrate 8 are arranged to face each other with a minute discharge space so that the scan electrode 2 and the sustain electrode 3 and the data electrode 10 are orthogonal to each other, and the periphery is sealed, and the discharge One or a mixed gas of helium, neon, argon, and xenon is sealed in the space as a discharge gas. In addition, the discharge space is divided into a plurality of sections by partition walls 11 to provide a plurality of discharge cells 13 at which the intersections of the display electrodes 4 and the data electrodes 10 are located. The phosphor layers 12 are sequentially arranged one by one so as to be blue.
[0007]
The electrode arrangement of this panel body is a matrix configuration comprising M rows × N columns of discharge cells, M rows of scan electrodes and sustain electrodes are arranged in the row direction, and N columns of data electrodes are arranged in the column direction. Has been.
[0008]
Conventionally, electrodes composed of a metal film mainly using a photosensitive conductive paste have been used for bus electrodes and data electrodes of the plasma display panel. The conductive paste containing the photo-crosslinking / photo-polymerizable photosensitive resin includes photo-crosslinking / photo-polymerization initiators, polymerization accelerators, monomer resins that contribute to the cross-linking / polymerization reaction, acrylic as an aggregate, etc. A binder resin, metal particles for electrical conduction, glass particles for adhesion to a substrate, and a solvent component.
[0009]
FIGS. 5A to 5E show an electrode manufacturing method using a conductive paste containing a photosensitive resin having photocrosslinking and photopolymerization properties and metal particles.
[0010]
First, as shown in FIG. 5A, the conductive paste film 15 is formed by applying the conductive paste on a substrate 14 such as glass by screen printing and drying it. Thereafter, in order to obtain a desired electrode pattern as shown in FIG. 5 (b), exposure light 16 such as ultraviolet rays is irradiated through a mask 17 formed in a predetermined pattern shape using a photolithography method, and necessary electrodes are formed. Cross-linking / polymerization reaction of the pattern portion is promoted to form an exposed portion 18 of the conductive paste as shown in FIG.
[0011]
Next, as shown in FIG. 5 (d), the exposed substrate 14 is developed, so that the unexposed portion does not undergo crosslinking / polymerization reaction, so that it is decomposed when immersed in a developer, and only the exposed portion is developed. The remaining electrode film 19 remains on the substrate 14.
[0012]
Finally, the substrate 14 is put into a firing furnace and subjected to heat treatment, whereby organic components contained in the electrode film 19 after development are removed by evaporation and combustion, and at the same time, metal particles are sintered to reduce resistance. At the same time, the glass particles are melted to improve the adhesion to the substrate 14. That is, as shown in FIG. 5E, the baked electrode 20 is formed in which the organic matter is removed and somewhat contracted.
[0013]
[Problems to be solved by the invention]
In order to obtain an electrode with a desired pattern shape, its shape is determined by exposure. Since exposure is performed from the upper part of the film coated and dried on the substrate, the upper cross-linking and polymerization are promoted, but the film thickness direction On the other hand, near the substrate, light is scattered by the metal particles contained in the paste, so that crosslinking / polymerization is hardly promoted. For this reason, when the development process is performed, the upper part is cross-linked and polymerized according to the electrode pattern, so the shape is maintained and remains, but the one near the substrate in the film thickness direction is not cross-linked and polymerized, so after development The electrode film 19 has a trapezoidal shape with a large upper area as shown in FIG. When this is fired, the organic matter gradually burns, shrinks, or the metal particles are sintered, so that the electrode 20 has a floating shape in which the end of the electrode warps as shown in FIG. turn into.
[0014]
Although the cause of such a shape is not clarified, when firing, removal of organic substances and sintering of metal particles proceed from the vicinity of the surface, so the surface area is first fixed, It is presumed that the organic matter is burned and removed, the volume shrinks, and as a result, a floating shape is generated in which the electrode end is warped.
[0015]
In order to control this, it is thought that the drying conditions, development conditions, baking conditions, the amount of organic matter in the paste, etc. must be controlled in detail, but within a large area substrate (42 inch or 50 inch size). Then, it was difficult to control them all uniformly.
[0016]
Further, in the plasma display, as shown in FIG. 7, a dielectric 21 is formed on the electrode 20 and a voltage is applied. However, in such a shape that the end of the electrode 20 is warped, the dielectric 21 is substantially effective. Since the actual film thickness of the dielectric 21 formed in this manner becomes small, the withstand voltage characteristic of the dielectric 21 deteriorates. When the film thickness of the dielectric 21 is increased to prevent this, the withstand voltage characteristic increases, but characteristic deterioration such as an increase in discharge voltage and a decrease in luminance due to a decrease in transmittance occurs.
[0017]
Further, bubbles 22 were mixed between the electrode 20 floating from the substrate 14 and the substrate 14 when the dielectric 21 was formed, and this also caused deterioration of characteristics such as breakdown voltage characteristics and light transmittance.
[0018]
This invention is made | formed in view of such a subject, and when forming an electrode pattern with an electrically conductive paste, it aims at preventing the curvature of an electrode edge part.
[0019]
[Means for Solving the Problems]
In order to achieve this object, the present invention provides an electrode in which a conductive paste composed of at least a photodegradable resin and metal particles is applied on a substrate, and then exposure and development are repeated a plurality of times so as to form a predetermined pattern shape. In the manufacturing method of the display device for forming the electrode, the region other than the portion where the electrode is formed is exposed, and the region of exposure performed after the first exposure is reduced .
[0020]
DETAILED DESCRIPTION OF THE INVENTION
That is, in the present invention, an electrode is formed from a conductive paste composed of at least a photodegradable resin and metal particles, and the shape of the electrode is configured such that the area of the contact surface with the lower layer is larger than the area of the upper surface. It is. In the present invention, a conductive paste containing glass particles is used, and silver or a silver alloy is used as the metal particles.
[0021]
In the manufacturing method of the present invention, after applying a conductive paste comprising at least a photodegradable resin and metal particles on a substrate, exposure and development are repeated a plurality of times so as to form an electrode so as to form a predetermined pattern shape. In the device manufacturing method, a region other than a portion where an electrode is to be formed is exposed, and a region of exposure performed after the first exposure is reduced .
[0022]
By adopting such a configuration, warping of the electrode is prevented. For example, in a plasma display, the withstand voltage characteristic after formation of the dielectric film formed on the electrode is improved, and a highly reliable electrode is obtained. There is an advantage that a display device using a high-quality electrode with high reliability can be stably obtained.
[0023]
Hereinafter, a display device according to an embodiment of the present invention will be described with reference to FIGS.
[0024]
FIG. 1 is a diagram showing an electrode manufacturing process using a conductive paste in a display device according to an embodiment of the present invention. The conductive paste is a photodegradable resin, a binder resin such as acrylic as an aggregate. It contains at least metal particles for ensuring electrical continuity and glass powder for adhering to the substrate. Specifically, O-quinonediazide is used as a photodegradable resin, an alkali-soluble novolac resin is used as a binder resin such as acrylic as an aggregate, and silver fine particles are used as metal particles for ensuring conduction. Barium-based glass powder is used for the glass particles to adhere to the substrate.
[0025]
First, as shown in FIG. 1A, the above-described conductive paste is applied on a substrate 31 by a printing method or the like and dried to form a conductive paste film 32 having a thickness of about 10 μm. Next, as shown in FIG. 1B, exposure light 34 is irradiated through a mask 33 to a portion unnecessary as an electrode. As a result, O-quinonediazide, which is a photodegradable resin of the exposed portion 35 exposed to light from the conductive paste film 32, is decomposed and dissolved in a developer composed of an alkaline solution during development. However, the light does not reach the vicinity of the substrate 31 because the metal particles are included in the conductive paste. That is, it reaches only about 3 to 4 microns from the surface layer, and the conductive paste film 32 is only removed to the depth by development with an alkaline solution, so that the developed electrode film 36 as shown in FIG. 1C remains. . As shown in FIG. 1D, a mask 37 that can irradiate light in a region narrower than the region previously irradiated with the exposure light is used for the substrate 31 on which the developed electrode film 36 is formed. Then, exposure is performed to form an exposed portion 38. By developing the substrate 31, a stepped electrode film 39 is formed as shown in FIG. Further, as shown in FIG. 1 (f), the exposure is performed by irradiating light 34 through a mask 40 having an exposure area narrower than that in the step of FIG. 1 (d) to form an exposed portion 41 and developing. A stepped electrode film 42 as shown in FIG. 1 (g) is formed.
[0026]
FIG. 2A shows an enlarged stepped electrode film 42 after development. In this way, exposure is performed from the upper surface of the film, removal is performed by photolysis, and the exposure area is reduced at the time of exposure. Therefore, the contact area with the substrate 31 is larger than the area of the upper surface of the electrode, and the lower part is not removed. An electrode film 42 that is not etched) can be obtained. The electrode 43 obtained by baking this film has a large contact area with the substrate 31 as shown in FIG. 2B, and is not punched. Therefore, the electrode end is warped and does not become a floating electrode. Therefore, as shown in FIG. 3, the dielectric 44 formed on the electrode 43 can also be formed with a small coating thickness even if the actual distance L from the electrode to the dielectric surface is the same. In addition, since the end portion of the electrode is not lifted, a highly reliable electrode can be obtained without bubbles remaining on the electrode.
[0027]
In this embodiment, O-quinonediazide as a photodegradable resin, a novolac resin as a binder, and a conductive paste using silver particles to obtain electrical conductivity, but are not limited to these, Any conductive paste having photodegradability using other materials may be used. In this embodiment, the exposure and development are performed three times. However, if a thin electrode film thickness is acceptable, a thin conductive paste film is formed and the exposure / development is repeated twice, so that a thick electrode film thickness is required. If so, it is sufficient to apply a thick conductive paste, form a dried film, and repeat exposure and development three or more times.
[0028]
Further, in the above description, the example in which the cross-sectional shape of the electrode 43 decreases in a stepped manner from the contact surface with the lower substrate 31 to the upper surface is shown. In short, the shape may be such that the area of the contact surface with the lower layer of the electrode 43 is larger than the area of the upper surface.
[0029]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent warping or the like of the electrode and to form a good electrode. In particular, in the plasma display panel, the withstand voltage characteristic after the formation of the dielectric film formed on the electrode becomes good, and a highly reliable plasma display panel can be obtained stably.
[Brief description of the drawings]
FIGS. 1A to 1G are schematic cross-sectional views showing a manufacturing process of an electrode of a display device according to an embodiment of the present invention. FIGS. 2A and 2B are electrodes of the display device. FIG. 3 is a schematic cross-sectional view showing an enlarged main part of the plasma display panel. FIG. 3 is a schematic cross-sectional view showing an enlarged main part structure when the present invention is applied to an electrode of a plasma display panel. [Fig. 5] (a) to (e) are schematic cross-sectional views showing a conventional electrode manufacturing method in the panel. [Fig. 6] (a) and (b) are enlarged views of the main electrode of the panel. FIG. 7 is a schematic cross-sectional view for explaining a conventional problem.
31 Substrate 32 Conductive Paste Film 34 Exposure Light 33, 37, 40 Mask 35, 38, 41 Exposed Area 36, 39, 42 Electrode Film 43 Electrode

Claims (1)

In a method for manufacturing a display device, an electrode is formed by applying a conductive paste composed of at least a photodegradable resin and metal particles on a substrate, and then forming an electrode by repeating exposure and development multiple times so as to form a predetermined pattern shape. A method for manufacturing a display device, characterized in that a region other than a portion where the film is formed is exposed and a region of exposure performed after the first exposure is reduced.

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