KR100447645B1 - A Plasma Display Panel - Google Patents

Abstract

The present invention relates to a front substrate of a plasma display panel, wherein sustain electrodes of the front substrate are composed of a transparent electrode and a bus electrode disposed on the transparent electrode, and a black layer for improving contrast is provided between the transparent electrode and the bus electrode. Formed; The black layer extends through the non-discharge region between the discharge cell and the discharge cell and extends between the transparent electrode and the bus electrode of the adjacent discharge cell; The bus electrode is formed on the black layer on the transparent electrode and on the black layer on the non-discharge region.

Therefore, according to the present invention, the luminance can be improved by widening the discharge region.

Description

Plasma Display Panel {A Plasma Display Panel}

The present invention relates to a front substrate of a plasma display panel, and more particularly, to improve luminance by moving a bus electrode formed on a transparent electrode to a non-discharge area when forming a front substrate of a plasma display panel. .

1 and 2 illustrate an exploded perspective view and a cross-sectional view showing a combined state in which a typical plasma display panel is separated.

As illustrated, the plasma display panel is coupled in parallel with the front substrate 10 and the rear substrate 20, which are display surfaces on which images are displayed, with a predetermined distance therebetween.

The transparent electrode (or ITO electrode) 11a formed of ITO (Indium Tin Oxide) material on the front substrate 10 and the bus electrode 11b made of metal such as silver (Ag) on the transparent electrode 11a A plurality of sustain electrodes 11 are arranged in parallel.

In general, silver (Ag) constituting the bus electrode is not known to transmit light due to discharge and reflects to external light, and thus has a problem of poor contrast. To solve this problem, a black electrode layer 11c is formed between the transparent electrode 11a and the bus electrode 11b to improve contrast.

The sustain electrode 11 is covered by a dielectric layer 12 that limits the discharge current and insulates the electrode pairs, and a protective layer 13 having magnesium oxide (MgO) deposited thereon to facilitate discharge conditions. Is formed.

In addition, between each of the sustain electrodes 11, a function of blocking light to reduce reflection by absorbing external light generated from the outside of the front substrate 10, and to improve the purity and contrast of the front substrate 10. A functioning black matrix 14 is arranged as shown in FIG.

The rear substrate 20 has an address discharge at a portion where a plurality of discharge spaces, that is, stripe-type (or well-type) barrier ribs 21 for forming cells are arranged in parallel and intersect with the sustain electrode 11. A plurality of address electrodes 22 are generated in parallel with the partition wall 21 to generate vacuum ultraviolet rays.

In addition, an upper surface of the rear substrate is coated with an RGB fluorescent layer 23 that emits visible light for displaying an image in the partition 21, and a dielectric layer 24 is formed on the upper side of the address electrode 22 by firing. Is formed.

Looking at the process of manufacturing the front substrate 10 in the conventional plasma display panel configured as described above are as follows.

3 (a) to 3 (g) illustrate a process of manufacturing a front substrate of a conventional plasma display panel, wherein the transparent electrode 11a of indium tin oxide (ITO) material is formed on the front substrate 10 in black. The black paste for forming the electrode layer is printed and dried at about 120 ° C. (a), and then printed with silver (Ag) paste for forming the bus electrode 11b thereon and dried (b). Next, after ultraviolet (UV) exposure using a photomask 30 (P / M) (c), after development, the resultant is calcined for about 3 hours in a kiln (not shown) of about 550 ° C. or more (d). Thereafter, the dielectric paste was printed and dried (e), and after the pattern was printed with the black matrix (BM) in the non-discharge region between the discharge cell and the discharge cell (f), the dielectric layer and the black matrix were simultaneously dried at about 550 ° C. In the above kiln (not shown), it is further baked for about 3 hours (g).

When forming electrodes in the manufacturing of the front substrate of the conventional plasma display panel, the black electrode layer 11c, the bus electrode 11b, and the black matrix are all printed and dried once at a time and are all completed by two firing steps. There was a long and costly problem.

In general, in order to improve the luminance, it is advantageous to increase the discharge area by making the distance between the bus electrodes in the discharge cell as wide as possible. However, the distance between the bus electrodes in the discharge cells is such that the front substrate structure of the conventional plasma display panel has a bus electrode formed in the transparent electrode within about 30 μm from the edge of the non-discharge area of the transparent electrode.

If formed on the side of the non-discharge region within 30 μm, silver (Ag) particles of the bus electrode migrate and combine with the lead component of the substrate (glass) to cause discoloration of the bus electrode, thereby decreasing the color temperature of the panel. The brightness is lowered. In addition, silver (Ag) particles of the bus electrode may migrate to cause breakdown.

Therefore, for this reason, the bus electrode is formed to be 30 µm or more inward from the corner of the non-discharge area of the transparent electrode. As a result, the spacing of the bus electrode is reduced, so that the discharge intensity is also reduced, thereby reducing the luminance.

It is therefore an object of the present invention to provide a plasma display panel which can simplify the manufacturing process and also improve the luminance.

1 is an exploded perspective view for showing a typical plasma display panel.

2 is a cross-sectional view illustrating a front substrate in a typical plasma display panel.

3 (a) to 3 (e) illustrate a front substrate manufacturing process of a conventional plasma display panel.

4 illustrates a front substrate of a plasma display panel according to the present invention;

5 (a) to 5 (e) illustrate a front substrate manufacturing process of the plasma display panel according to the present invention;

6 is a view showing a method for measuring the contact resistance of the black layer according to the present invention.

7A and 7B are diagrams illustrating pinhole phenomenon and electrode bubble phenomenon of the black matrix, respectively.

8 (a) to 8 (e) show respective cases in which the bus electrode moves from the edge of the transparent electrode in contact with the non-discharge region to the inside of the discharge region or toward the non-discharge region;

*** Explanation of symbols for main parts of drawing ***

10,20; front and rear substrate 11; holding electrode

11a; transparent electrode 11b; bus electrode

11c; black (electrode) layer 14; black matrix

Technical solution of the present invention for achieving the above object, the front substrate and the rear substrate arranged at a predetermined interval, a plurality of sustain electrodes arranged in parallel to the front substrate, the back substrate crosses the sustain electrodes 10. A plasma display panel comprising a plurality of data electrodes arranged in a direction and partition walls disposed at predetermined intervals between the front substrate and the rear substrate to partition discharge cells, wherein the sustain electrodes of the front substrate are formed of a transparent electrode. A bus layer disposed on the transparent electrode, and a black layer for contrast enhancement is formed between the transparent electrode and the bus electrode; The black layer extends through the non-discharge region between the discharge cell and the discharge cell and extends between the transparent electrode and the bus electrode of the adjacent discharge cell; The bus electrode is formed on the black layer on the transparent electrode and on the black layer on the non-discharge region.

Further, when the width of the bus electrode is L, it is preferable that the width of the bus electrode in contact with the black layer on the non-discharge area is 1/8 L to 5/8 L.

The black layer formed between the transparent electrode and the bus electrode is formed to a thickness of 0.1 ~ 5㎛, preferably comprises a high softening point frit glass of 450 ℃ or more.

The black layer is a black powder and includes at least one of cobalt (Co) oxide, chromium (Cr) oxide, manganese (Mn) oxide, copper (Cu) oxide, iron (Fe) oxide, and carbon (C) oxide. It is preferable to include at least one of PbO-B ₂ O ₃ -Bi ₂ O _3, ZnO-SiO ₂ -Al ₂ O _3, and PbO-B ₂ O ₃ -CaO-SiO ₂ as a frit glass. .

In addition, the black paste for forming the black layer preferably contains 5 to 30% by weight of the frit glass.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention for achieving the above object will be described in detail.

For convenience of description, the same parts and members as in the prior art will be described with the same reference numerals as in the prior art.

In order to reduce the number of steps for fabricating the conventional front substrate shown in FIG. 3, the inventors of the adjacent discharge cells completely cover the non-discharge region between the discharge cells and the discharge cells as shown in FIG. A structure which extends between the transparent electrode 11a and the bus electrode 11b is proposed.

5 (a) to 5 (e) illustrate a process of manufacturing the front substrate of the plasma display panel according to the present invention shown in FIG. 4, wherein the transparent electrode of indium tin oxide (ITO) material on the front substrate 10 After printing the black paste for forming the black layer 11c in the state in which the 11a is formed, and drying it to about 120 ° C., the black layer is formed as shown in FIG. 4 using the first photomask 30 (P / M). The part is exposed (a), and a silver (Ag) paste for forming the bus electrode 11b is printed thereon and dried (b). Next, the bus electrode forming part was exposed to ultraviolet (UV) light using a second photomask 30 '(P / M) (c), and then developed for 3 hours in a firing furnace (not shown) of about 550 ° C. or more. Firing for a while (d). Thereafter, the dielectric paste is printed and dried and then fired (e).

As shown in Figs. 4 and 5 (a) to 5 (e), according to the present invention, the black layer 11c interposed under the bus electrode 11b is formed to cover the non-discharge region without forming a separate black matrix. By forming, the manufacturing process can be simplified and the manufacturing cost can be reduced.

As described above, when the black layer 11c is formed using conductive ruthenium oxide (RuO ₂ ) as the black powder, a short circuit phenomenon occurs between adjacent cells.

Accordingly, the inventors have found that the black powder is a non-conductive cobalt (Co) oxide, chromium (Cr) oxide, manganese (Mn) oxide, copper (Cu) oxide, iron (Fe) instead of conductive ruthenium oxide (RuO ₂ ). Cobalt-based oxide (CoO ₂ ) of the (C) -based oxide and carbon (C) -based oxide was selected and included in the black layer, and the number of experiments were performed while varying the thickness, and the results are shown in Table 1 below. This experiment applied the same process conditions and the same frit glass.

Frit glass content (% by weight) Film thickness (㎛) Contact resistance (ITO / BUS electrode) Initial discharge voltage (V) Adhesion 5 0.1 4 181 △ 10 0.3 6 180 ○ 15 1.2 6 182 ◎ 20 2.5 8 182 ◎ 25 4.1 9 182 ◎ 30 5.0 10 185 ◎ 35 5.8 20 261 ◎ 40 6.1 27 267 ◎ 45 6.1 28 267 ◎ 50 3.6 28 268 ◎

In Table 1, the frit glass content refers to the amount contained in the black layer paste, and the thickness of the black layer is adjusted according to the frit glass content in the paste.

In the method for measuring contact resistance of Table 1, as shown in FIG. 6, the black layer 40 is formed into a 5 cm long square, and then a rectangular silver (Ag) electrode 41 having a width of about 3 cm is formed thereon. Next, the transparent electrode 42 ITO is drawn out from the silver electrode to extend beyond the black layer. At this time, the resistance between the point 1 on the silver electrode 41 and the point 2 of the black layer 40 is measured.

As shown in Table 1, when the amount of frit glass contained in the black paste was adjusted to 5 to 30% by weight, the black layer had a thickness of 0.1 to 5 µm, at which time the contact resistance was 4 to 10 kPa. The discharge voltage was also 181 to 185V. On the other hand, when the amount of frit glass contained in the black paste was adjusted to 35% by weight or more, the thickness of the black layer was 5.8 µm or more, and the contact resistance was very high at 20 kV and the initial discharge voltage was 261V.

As a result, the black layer including the cobalt oxide black powder exhibits good conductivity with a contact resistance of 10 kΩ or less when the thickness is 5.0 μm or less, and thus the bus electrode 11b is interposed between the bus electrode 11b and the transparent electrode. In the case of more than 5 μm, the contact resistance rapidly increases, and thus the bus electrode 11b may not play a sufficient role.

Moreover, inexpensive cobalt (Co) oxide, chromium (Cr) oxide, manganese (Mn) oxide, copper (Cu) oxide, iron (Fe) oxide, carbon (C) without using expensive ruthenium oxide By using at least one of the oxides, the manufacturing cost can be reduced.

As a component contained in the conventional black electrode layer 11c, in addition to ruthenium oxide, which is a conductive black powder, PbO-B ₂ O ₃ -SiO ₂ three-phase frit glass having a softening point of about 425 ° C. to provide adhesion of the black electrode layer. Is contained. The present inventors applied a PbO-B ₂ O ₃ -SiO ₂ three-phase frit glass having a softening point of about 425 ° C. while reducing the thickness of the black layer to 5 μm or less. In 14), a plurality of pin holes are generated, and bubbles are generated in the black layer between the bus electrode and the transparent electrode as shown in FIG. 7B.

Therefore, in order to solve this problem, the present inventors have performed experiments to determine adhesion strength, pin hole generation, and electrode bubble generation according to the softening point of the frit glass to be contained, as shown in Table 2 below. As frit glass having a softening point of about 450 ° C. or more, mainly fructose glass of PbO-B ₂ O ₃ -Bi ₂ O ₃ or ZnO-SiO ₂ -Al ₂ O ₃ three-phase, PbO-B ₂ O ₃ -CaO-SiO ₂ four-phase frit glass One or two or more of them were mixed and used.

In Table 2, adhesive strength was indicated as ◎ (strong), ○ (usually), △ (weak), and pinhole and electrode bubble generation degree was indicated as ◎ (high), ○ (normal), and × △ (low).

Fritted glass softening store Adhesion Pinhole Electrode bubble 400 ℃ △ ◎ ◎ 415 ℃ ○ ◎ ◎ 430 ℃ ○ ◎ ◎ 450 ℃ ◎ ○ ○ 480 ℃ ◎ × × 510 ℃ ◎ × × 550 ℃ ◎ × × 580 ℃ △ × ×

As shown in Table 2, the use of a high softening point frit glass of 450 ° C. or higher provided good adhesion, and as a result, the occurrence of pinholes and electrode bubbles was also significantly reduced.

As described above, the inventors proposed a new structure in which the bus electrode 11b is moved over the black layer of the non-discharge region to improve the luminance based on the structure in which the black layer extends to completely cover the non-discharge region. That is, as shown in Figs. 8A to 8F, experiments were conducted to confirm changes in efficiency (lm / W), power consumption (W), and brightness (cd / m 2) when the bus electrodes were moved. The results are shown in Table 3 below.

8A is a conventional structure, 8B is an ideal case structure that cannot be actually applied in the prior art, and FIGS. 8C to 8F show a bus electrode structure according to the present invention.

Bus electrode position Efficiency (lm / W) Power Consumption (W) Luminance (cd / ㎡) Conventional 0.91 2.30 128 0 1.02 2.30 149 1 / 8ℓ 1.02 2.50 155 2 / 8ℓ 1.05 2.50 160 3 / 8ℓ 1.07 2.60 170 4 / 8ℓ 1.05 2.80 180 5 / 8ℓ 1.03 2.40 185 6 / 8ℓ 0.80 3.80 200 7 / 8ℓ 0.40 10.0 230

As shown in Table 3, as the distance between the bus electrodes in the discharge cell increases, the power consumption increases, but the luminance is improved. However, in the case of 1/8 L or less, the effect of improving the brightness is somewhat less. If the deviation is more than 6/8 L of the bus electrode toward the non-discharge area, the luminance increases, but the power consumption (holding voltage x discharge current) becomes excessively high. 5/8 L is preferred.

As described above, it is difficult to apply the structure in which the bus electrode 11b is moved toward the non-discharge area, in the same structure as the conventional black layer, and as shown in FIG. Is formed by extending between the transparent electrode 11a and the bus electrode 11b of the adjacent discharge cell so as to completely cover the gap, so that the black layer is formed at the same height even in the non-discharge area.

As described in detail above, according to the present invention, the manufacturing process can be simplified by improving the structure of the black layer, thereby reducing the manufacturing cost and improving the structure of the bus electrode, thereby improving the luminance.

Although the preferred embodiments have been described so far, the present invention is not limited thereto, and various modifications can be used by those skilled in the art. However, it is apparent that such modifications fall within the scope of the present invention.

Claims (5)

A front substrate and a rear substrate arranged at regular intervals, a plurality of sustain electrodes arranged in parallel to the front substrate, a plurality of data electrodes arranged in a direction crossing the sustain electrodes on the back substrate, and the front surface A plasma display panel comprising barrier ribs disposed at a predetermined distance between a substrate and a rear substrate to partition discharge cells. Sustain electrodes of the front substrate are composed of a transparent electrode and a bus electrode disposed on the transparent electrode, and a black layer for contrast enhancement is formed between the transparent electrode and the bus electrode; The black layer extends through the non-discharge region between the discharge cell and the discharge cell and extends between the transparent electrode and the bus electrode of the adjacent discharge cell; The bus electrode formed on the black layer is formed to be positioned on the interface between the transparent electrode and the non-discharge area. When the width of the bus electrode is 1, the width of the bus electrode in contact with the black layer on the non-discharge area is 1/8 L to 5/8 L, The black layer is composed of a non-conductive oxide as a black powder, PbO-B ₂ O ₃ -Bi ₂ O _3, ZnO-SiO ₂ -Al ₂ O ₃ and PbO-B ₂ O ₃ -CaO-SiO ₂ as frit glass And at least one of the plasma display panel. (delete) The method of claim 1, The black layer is a black powder and includes at least one of cobalt (Co) oxide, chromium (Cr) oxide, manganese (Mn) oxide, copper (Cu) oxide, iron (Fe) oxide, and carbon (C) oxide. Plasma display panel comprising one. (delete) The method of claim 1, And a black paste for forming the black layer comprises 5 to 30% by weight of frit glass.