KR20080057984A - Plasma display device - Google Patents

Abstract

A plasma display apparatus is provided to improve the strength thereof by forming plural dielectrics whose thermal expansive coefficients are different from each other on an upper substrate. A pair of sustain electrodes(11,12) and a dielectric are formed on an upper substrate(10). A lower substrate(20) is arranged to be opposite to the upper substrate. An address electrode(22) is formed on the lower substrate. The dielectric is comprised of a first dielectric and a second dielectric. The second dielectric has a different thermal expansive coefficient from the first dielectric. The first dielectric has a thermal expansive coefficient lower than that of the second dielectric. The first dielectric and the second dielectric are sequentially laminated on the upper substrate. The thermal expansive coefficient of the first dielectric is 0.0000075 or 0.0000080.

Description

Plasma Display device

1 is a view showing an embodiment of the structure of a plasma display panel according to the present invention;

FIG. 2 is a diagram illustrating an upper dielectric layer in the structure of a plasma display panel of the present invention.

3 is a view for explaining the effect on the structure of the upper dielectric layer of the present invention shown in FIG.

4 illustrates an embodiment of an electrode arrangement of a plasma display panel;

FIG. 5 is a timing diagram illustrating an embodiment of a time division driving method by dividing a frame into a plurality of subfields. FIG.

The present invention relates to a plasma display device, and more particularly, to a structure of a dielectric layer formed on an upper substrate of a panel.

In general, a plasma display panel is a partition wall formed between an upper substrate and a lower substrate to form one unit cell, and each cell includes neon (Ne), helium (He), or a mixture of neon and helium (Ne + He) and An inert gas containing the same main discharge gas and a small amount of xenon is filled. When discharged by a high frequency voltage, the inert gas generates vacuum ultraviolet rays and emits phosphors formed between the partition walls to realize an image. Such a plasma display panel has a spotlight as a next generation display device because a thin and light configuration is possible.

As such, the plasma display panel is generally manufactured to have a small thickness, and thus has a problem of being easily broken from external impact. In order to improve this, a glass filter having excellent mechanical strength is installed on the front of the panel. However, the glass filter has a high price, which causes the manufacturing cost of the PDP to increase, thereby reducing the manufacturing cost of the PDP and improving the mechanical strength of the panel. There is a need for other ways to improve.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and by forming a dielectric layer formed on an upper substrate in a plasma display panel with a plurality of layers having different thermal expansion coefficients, it is possible to reduce manufacturing costs and improve panel strength. It is an object of the present invention to provide a plasma display device which can be ensured reliability.

Plasma display device of the present invention for solving the above technical problem is an upper substrate; A sustain electrode pair and a dielectric layer formed on the upper substrate; A lower substrate disposed to face the upper substrate; And an address electrode formed on the lower substrate, wherein the dielectric layer comprises: a first dielectric layer; And a second dielectric layer having a thermal expansion coefficient different from that of the first dielectric layer.

The first dielectric layer has a lower coefficient of thermal expansion than the second dielectric layer, and is preferably stacked on the upper substrate in the order of the first dielectric layer and the second dielectric layer.

In addition, the coefficient of thermal expansion of the first dielectric layer is 0.0000075 to 0.0000080, and the coefficient of thermal expansion of the second dielectric layer is preferably 0.0000085 to 0.0000090.

Hereinafter, a plasma display device according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view showing an embodiment of the structure of a plasma display panel of the present invention.

As shown in FIG. 1, the plasma display panel includes a scan electrode 11, a sustain electrode 12, a sustain electrode pair formed on the upper substrate 10, and an address electrode 22 formed on the lower substrate 20. It includes.

The sustain electrode pairs 11 and 12 generally include transparent electrodes 11a and 12a and bus electrodes 11b and 12b formed of indium tin oxide (Indi μm-Tin-Oxide; ITO), and the bus electrodes 11b. , 12b) may be formed of a metal such as silver (Ag) or chromium (Cr) or a stack of chromium / copper / chromium (Cr / Cu / Cr) or a stack of chromium / aluminum / chromium (Cr / Al / Cr). have. The bus electrodes 11b and 12b are formed on the transparent electrodes 11a and 12a to reduce the voltage drop caused by the transparent electrodes 11a and 12a having high resistance.

Meanwhile, according to the exemplary embodiment of the present invention, the sustain electrode pairs 11 and 12 may not only have a structure in which the transparent electrodes 11a 12a and the bus electrodes 11b and 12b are stacked, but also the buses without the transparent electrodes 11a and 12a. Only the electrodes 11b and 12b may be configured. This structure does not use the transparent electrodes (11a, 12a), there is an advantage that can lower the cost of manufacturing the panel. The bus electrodes 11b and 12b used in this structure may be various materials such as photosensitive materials in addition to the materials listed above.

Light between the scan electrodes 11 and the sustain electrodes 12 between the transparent electrodes 11a and 12a and the bus electrodes 11b and 11c to absorb external light generated outside the upper substrate 10 to reduce reflection. A black matrix (BM, 15) is arranged that functions to block and to improve the purity and contrast of the upper substrate 10.

The black matrix 15 according to the exemplary embodiment of the present invention is formed on the upper substrate 10, the first black matrix 15 and the transparent electrodes 11a and 12a formed at positions overlapping the partition wall 21. And the second black matrices 11c and 12c formed between the bus electrodes 11b and 12b. Here, the first black matrix 15 and the second black matrices 11c and 12c, also referred to as black layers or black electrode layers, may be simultaneously formed and physically connected in the formation process, or may not be simultaneously formed and thus not physically connected. .

In addition, when physically connected and formed, the first black matrix 15 and the second black matrix 11c and 12c may be formed of the same material, but may be formed of different materials when they are formed separately.

The upper dielectric layer 13 and the passivation layer 14 are stacked on the upper substrate 10 having the scan electrode 11 and the sustain electrode 12 side by side. Charged particles generated by the discharge are accumulated in the upper dielectric layer 13, and the protective electrode pairs 11 and 12 may be protected. In addition, the upper dielectric layer 13 is formed of two layers having different thermal expansion coefficients, thereby increasing the strength of the panel so that it is not easily broken from external impact.

The protective film 14 protects the upper dielectric layer 13 from sputtering of charged particles generated during gas discharge, and increases emission efficiency of secondary electrons.

In addition, the address electrode 22 is formed in a direction crossing the scan electrode 11 and the sustain electrode 12. In addition, a lower dielectric layer 24 and a partition wall 21 are formed on the lower substrate 20 on which the address electrode 22 is formed.

In addition, the phosphor layer 23 is formed on the surfaces of the lower dielectric layer 24 and the partition wall 21. The partition wall 21 has a vertical partition wall 21a and a horizontal partition wall 21b formed in a closed shape, and physically distinguishes the discharge cells, and prevents ultraviolet rays and visible light generated by the discharge from leaking into adjacent discharge cells. have.

In an embodiment of the present invention, not only the structure of the partition wall 21 illustrated in FIG. 1, but also the structure of the partition wall 21 having various shapes may be possible. For example, a channel in which a channel usable as an exhaust passage is formed in at least one of the differential partition structure, the vertical partition 21a, or the horizontal partition 21b having different heights of the vertical partition 21a and the horizontal partition 21b. A grooved partition structure having a groove formed in at least one of the type partition wall structure, the vertical partition wall 21a, or the horizontal partition wall 21b may be possible.

Here, in the case of the differential partition wall structure, the height of the horizontal partition wall 21b is more preferable, and in the case of the channel partition wall structure or the groove partition wall structure, it is preferable that a channel is formed or the groove is formed in the horizontal partition wall 21b. something to do.

Meanwhile, in one embodiment of the present invention, although the R, G and B discharge cells are shown and described as being arranged on the same line, it may be arranged in other shapes. For example, a Delta type arrangement in which R, G, and B discharge cells are arranged in a triangular shape may be possible. In addition, the shape of the discharge cell may be not only rectangular, but also various polygonal shapes such as a pentagon and a hexagon.

In addition, the phosphor layer 23 emits light by ultraviolet rays generated during gas discharge to generate visible light of any one of red (R), green (G), and blue (B). Here, an inert mixed gas such as He + Xe, Ne + Xe and He + Ne + Xe for discharging is injected into the discharge space provided between the upper / lower substrates 10 and 20 and the partition wall 21.

2 is a diagram illustrating the upper dielectric layer in the structure of the plasma display panel of the present invention.

An embodiment of the structure of a panel according to the present invention will be described with reference to the diagram shown in FIG. 2, but duplicated contents described with reference to FIG. 1 will be omitted. The plasma display panel according to the present invention includes an upper substrate 100, a first dielectric layer 141 formed on the upper substrate 100, a second dielectric layer 142 having a different thermal expansion coefficient from the first dielectric layer, As described above, the upper dielectric layer includes a plurality of layers.

The upper dielectric layer of the present invention is formed of a plurality of layers having different coefficients of thermal expansion, for example, the first dielectric layer 141 and the second dielectric layer 142. As shown in FIG. 2, the first dielectric layer 141 directly formed on the upper substrate 100 preferably has a coefficient of thermal expansion smaller than that of the second dielectric layer 142 stacked on the first dielectric layer 141. .

The materials constituting the first dielectric layer 141 and the second dielectric layer 142 are made of most materials that are commonly used to satisfy transmittance and permittivity suitable for a panel. For example, lead oxide, silicon dioxide, boron oxide and barium oxide are used as main elements of the material forming the dielectric layer, and at least one of the listed materials may be omitted. In the present invention, some materials are added to the first dielectric layer 141 and the second dielectric layer 142 so as to have different coefficients of thermal expansion and a suitable coefficient of thermal expansion as the dielectric layer of the panel. For example, the first and second dielectric layers may be formed by adding a small amount of materials having properties such as increasing or decreasing the coefficient of thermal expansion such as bismuth oxide (Bi 2 O 3) and alkali oxides.

As described above, the plasma display panel having the upper dielectric layer formed of a plurality of layers having different thermal expansion coefficients has excellent mechanical strength and is not easily broken from external impact.

3 is a view for explaining the effect on the upper dielectric layer structure of the present invention shown in FIG.

Referring to FIG. 3, by lowering the coefficient of thermal expansion of the first dielectric layer 141 directly formed on the upper substrate 100 than the second dielectric layer 142, it is possible to improve the mechanical strength of the panel. In more detail, the coefficient of thermal expansion of the upper substrate 100, which is typically made of glass, has a higher coefficient of thermal expansion than the first dielectric layer 141 directly formed on the upper substrate 100. For example, the thermal expansion coefficient of the upper substrate 100 is 0.0000085, and the first dielectric layer 141 has a thermal expansion coefficient of 0.000075 to 0.0000080. As such, when the upper substrate 100 and the first dielectric layer 141 having different thermal expansion coefficients are bonded to each other, a compressive stress is formed on the outer surface of the upper substrate 100 and the upper substrate (141) is stacked. Tensile stress is formed on the inner surface of 100). In addition, a compressive stress is formed on one surface of the first dielectric layer 141 that is directly bonded to the inner surface of the upper substrate 100 so that the inner surface of the upper substrate 100 corresponds to a tensile stress, and one surface of the first dielectric layer 141 is formed. Since compressive stress is formed on the other surface of the first dielectric layer 141, tensile stress is formed.

As described above, in the case of a panel structure in which an upper dielectric layer consisting of only the first dielectric layer 141 is formed, when an impact is applied from the outside of the panel in the direction of the arrow, the first dielectric layer ( Since the force 141 is applied to the partition wall 210, the force of the first dielectric layer 141 pressed toward the partition wall 210 and the sustaining force of the partition wall 210 act to damage the first dielectric layer 141. . In order to prevent this, in the present invention, the second dielectric layer 142 having a higher thermal expansion coefficient than the first dielectric layer 141 is stacked on the first dielectric layer 141 to form an upper dielectric layer. In such a case, since the second dielectric layer 142 has a higher coefficient of thermal expansion than the first dielectric layer 141, one surface of the second dielectric layer 142, which is not in contact with the other surface of the first dielectric layer 141, that is, the partition 210 and Adjacent faces form compressive stresses. Since compressive stress is formed on one surface of the second dielectric layer 142, tensile stress is formed on the other surface of the second dielectric layer 142. Accordingly, a tensile stress is formed in the middle of the first dielectric layer 141 so that the compressive stress is formed on the other surface of the first dielectric layer 141, that is, the surface in contact with the other surface of the second dielectric layer 142. As such, when the upper dielectric layer is formed by stacking a second dielectric layer having a higher thermal expansion coefficient than that of the first dielectric layer 141, since the compressive stress is simultaneously formed on the outer surface of the upper substrate and the one surface of the second dielectric layer, impact from the outside is increased. Even if applied, the mechanical strength of the panel is excellent because it is not easily bent by the compressive stress.

Accordingly, in order to simplify the manufacturing process and prevent manufacturing costs from increasing, the first dielectric layer 141 preferably uses substantially the same materials as those used to form the upper dielectric layer. The thermal expansion coefficient of the dielectric layer 141 may have a 0.0000075 to 0.0000080.

In addition, the thermal expansion coefficient of the second dielectric layer 142 is preferably formed to have a thermal expansion coefficient similar to that of the upper substrate 100. Accordingly, the thermal expansion coefficient of the second dielectric layer 142 is preferably 0.000085 to 0.0000090. In such a case, by having a higher coefficient of thermal expansion than the first dielectric layer 141, it is possible to increase the mechanical strength of the panel, it is possible to prevent the loss of strength of the panel due to the difference in thermal expansion coefficient with the upper substrate.

On the other hand, in the present invention has been described in the embodiment that the upper dielectric layer is composed of two layers having different coefficients of thermal expansion, it may be formed of more layers. However, considering the thickness of the panel, it is most preferable that the dielectric layer consist of two layers.

FIG. 4 illustrates an embodiment of an electrode arrangement of a plasma display panel, and a plurality of discharge cells constituting the plasma display panel is preferably arranged in a matrix form as shown in FIG. 4. The plurality of discharge cells are provided at the intersections of the scan electrode lines Y1 to Ym, the sustain electrode lines Z1 to Zm, and the address electrode lines X1 to Xn, respectively. The scan electrode lines Y1 to Ym may be driven sequentially or simultaneously, and the sustain electrode lines Z1 to Zm may be driven simultaneously. The address electrode lines X1 to Xn may be driven by being divided into odd-numbered lines and even-numbered lines, or sequentially driven.

Since the electrode arrangement shown in FIG. 4 is only an embodiment of the electrode arrangement of the plasma panel according to the present invention, the present invention is not limited to the electrode arrangement and driving method of the plasma display panel shown in FIG. 4. For example, a dual scan method in which two scan electrode lines among the scan electrode lines Y1 to Ym are simultaneously scanned may be possible. In addition, the address electrode lines X1 to Xn may be driven by being divided up and down in the center portion of the panel.

FIG. 5 is a timing diagram illustrating an embodiment of a time division driving method by dividing a frame into a plurality of subfields. The unit frame may be divided into a predetermined number, for example, eight subfields SF1, ..., SF8 in order to realize time division gray scale display. Each subfield SF1, ... SF8 is divided into a reset section (not shown), an address section A1, ..., A8 and a sustain section S1, ..., S8.

Here, according to an embodiment of the present invention, the reset period may be omitted in at least one of the plurality of subfields. For example, the reset period may exist only in the first subfield or may exist only in a subfield about halfway between the first subfield and all the subfields.

In each address section A1, ..., A8, a display data signal is applied to the address electrode X, and scan pulses corresponding to each scan electrode Y are sequentially applied.

In each of the sustain periods S1, ..., S8, a sustain pulse is alternately applied to the scan electrode Y and the sustain electrode Z to form wall charges in the address periods A1, ..., A8. Sustain discharge occurs in the discharge cells.

The luminance of the plasma display panel is proportional to the number of sustain discharge pulses in the sustain discharge periods S1, ..., S8 occupied in the unit frame. When one frame forming one image is represented by eight subfields and 256 gradations, each subfield in turn has different sustains at a ratio of 1, 2, 4, 8, 16, 32, 64, and 128. The number of pulses can be assigned. In order to obtain luminance of 133 gradations, cells may be sustained by addressing the cells during the subfield 1 section, the subfield 3 section, and the subfield 8 section.

The number of sustain discharges allocated to each subfield may be variably determined according to weights of the subfields according to the APC (Automatic Power Control) step. That is, in FIG. 5, a case in which one frame is divided into eight subfields has been described as an example. However, the present invention is not limited thereto, and the number of subfields forming one frame may be variously modified according to design specifications. . For example, the plasma display panel may be driven by dividing one frame into eight or more subfields, such as 12 or 16 subfields.

The number of sustain discharges allocated to each subfield can be variously modified in consideration of gamma characteristics and panel characteristics. For example, the gray level assigned to subfield 4 may be lowered from 8 to 6, and the gray level assigned to subfield 6 may be increased from 32 to 34.

Although a preferred embodiment of the present invention has been described in detail above, those skilled in the art to which the present invention pertains can make various changes without departing from the spirit and scope of the invention as defined in the appended claims. It will be appreciated that modifications or variations may be made. Accordingly, modifications to future embodiments of the present invention will not depart from the technology of the present invention.

According to the present invention configured as described above, by forming the upper dielectric layer formed on the upper substrate of the panel of two layers having different coefficients of thermal expansion, the strength of the panel can be improved, thereby increasing the reliability of the panel. Will be.

In addition, by securing the mechanical strength of the panel, there is no need to separately install a panel protection device such as an expensive glass filter, there is an effect that can reduce the manufacturing cost of the plasma display device.

Claims (5)

Upper substrate; A sustain electrode pair and a dielectric layer formed on the upper substrate; A lower substrate disposed to face the upper substrate; And an address electrode formed on the lower substrate, The dielectric layer comprises a first dielectric layer; And And a second dielectric layer having a different thermal expansion coefficient from the first dielectric layer. The method according to claim 1, And the first dielectric layer has a lower coefficient of thermal expansion than the second dielectric layer. The method according to claim 2, And a first dielectric layer and a second dielectric layer on the upper substrate in this order. The method according to claim 1, And a thermal expansion coefficient of the first dielectric layer is 0.0000075 to 0.0000080. The method according to claim 1, And a thermal expansion coefficient of the second dielectric layer is 0.0000085 to 0.0000090.

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