KR20080038642A - Plasma display panel - Google Patents

Abstract

A plasma display panel is provided to improve bright room contract by forming a transparent electrode and a bus electrode as first and second electrodes, in which the bus electrode is composed of a white layer and plural black layers. A first substrate and a second substrate are opposite to each other, and barrier ribs(16) are interposed between the first and second substrates to define discharge cells(17) between the substrates. A phosphor layer is formed in the discharge cells, and address electrodes(11) are disposed in a first direction on the first substrate. A first electrode(31) and a second electrode(32) are opposite to each other in the discharge cell and are formed on the second substrate in a second direction crossing the address electrodes. A dielectric layer is formed on the second substrate to cover the first and second electrodes. Each of the first and second electrodes has transparent electrodes(31a,32a) formed on the second substrate and bus electrodes(31b,32b) formed on the transparent electrodes. The bus electrode has a black layer and a white layer.

Description

Plasma Display Panel {PLASMA DISPLAY PANEL}

1 is a perspective view schematically illustrating an exploded view of a plasma display panel according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.

3 is a plan view illustrating a disposition relationship between discharge cells and electrodes in an embodiment of the present invention.

Fig. 4 is a sectional view showing an operating state in which external light is absorbed by the bus electrode.

<Explanation of symbols for the main parts of the drawings>

10: first substrate (back substrate) 11: address electrode

13, 21: dielectric layer 16: partition wall

16a: first partition member 16b: second partition member

17 discharge cell 19 phosphor layer

20: second substrate (front substrate) 23: protective film

31: first electrode (holding electrode) 31a, 32a: transparent electrode

31b, 32b: bus electrode 32: second electrode (scanning electrode)

231c and 232c: first black layer 231d and 232d: second black layer

131, 132: white layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to a plasma display panel that improves bright room contrast by improving black fraction.

In general, a plasma display panel is a visible light of red (R), green (G) and blue (B) generated by exciting the phosphor using a vacuum ultra-violet (VUV) emitted from the plasma obtained through gas discharge It is a display device for implementing an image.

As an example, an AC plasma display panel forms address electrodes on a back substrate and covers the address electrodes with a dielectric layer. The partition walls are disposed between the address electrodes on the dielectric layer to form a stripe shape, and phosphor layers of red (R), green (G), and blue (B) layers are formed on the partition walls. On the front substrate facing the rear substrate, display electrodes composed of a pair of sustain electrodes and scan electrodes are formed along the direction crossing the address electrodes, and a dielectric layer and an MgO protective film cover the display electrodes. The discharge cell is formed at the point where the pair of address electrodes on the rear substrate and the pair of display electrodes on the front substrate cross each other. In the plasma display panel, millions of unit discharge cells are arranged in a matrix form.

The memory characteristic is used to drive the discharge cells of the plasma display panel. In more detail, in order to generate a discharge between the sustain electrode and the scan electrode constituting the pair of display electrodes, a potential difference of more than a specific voltage is required, and the voltage at this boundary is called a firing voltage (Vf). When the scan voltage and the address voltage are respectively applied to the scan electrode and the address electrode, the discharge is started to form a plasma in the discharge cell, and the electrons and ions of the plasma move toward the electrodes having opposite polarities.

On the other hand, a dielectric layer is applied to each electrode of the plasma display panel, so that most of the moved space charges are stacked on the dielectric layer having opposite polarity, so that the net space potential between the scan electrode and the address electrode is originally applied to the address. The voltage becomes lower than the voltage Va, the discharge is weakened, and the address discharge is extinguished. At this time, a relatively small amount of electrons are accumulated in the sustain electrode, and a relatively large amount of ions are accumulated in the scan electrode. The charges accumulated on the sustain electrode and the dielectric layer covering the scan electrode are wall charged (Qw). The space voltage formed between the sustain electrode and the scan electrode by these wall charges is referred to as wall voltage (Vw).

Subsequently, when the discharge sustain voltage Vs is applied to the sustain electrode and the scan electrode, the sum of the magnitudes of the discharge sustain voltage Vs and the wall voltage Vw (Vs + Vw) is the discharge start voltage Vf. If higher, sustain discharge occurs in the discharge cell. The vacuum ultraviolet (VUV) generated at this time excites the phosphor and emits visible light through the transparent front substrate.

However, when there is no address discharge between the scan electrode and the address electrode (that is, when the address voltage Va is not applied), wall charges do not accumulate between the sustain electrode and the scan electrode, and consequently, the sustain electrode and the scan electrode. There is no wall voltage in between. At this time, only the discharge sustain voltage Vs applied to the sustain electrode and the scan electrode is formed in the discharge cell. Since the discharge sustain voltage is lower than the discharge start voltage Vf, the gas space between the sustain electrode and the scan electrode cannot be discharged.

Various attempts have been made to improve the contrast of black room by improving the ratio of black, that is, the black portion of the plasma display panel. For example, there is a plasma display panel in which a display electrode is formed of a transparent electrode and a bus electrode, and a black part is formed from the bus electrode.

The bus electrode is formed of a white layer having excellent electrical conductivity and a black layer forming a black portion. In general, since the black layer is formed as one layer on the white layer, the black layer has an external light absorption performance depending on an area in a direction parallel to the front substrate.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma display panel which improves bright room contrast by improving black ratio while maintaining the area of the black layer in a direction parallel to the front substrate.

According to an embodiment of the present invention, a plasma display panel includes a first substrate and a second substrate facing each other, a partition wall disposed between the two substrates to partition discharge cells, a phosphor layer formed in the discharge cells, An address electrode formed along the first direction on the first substrate, a first electrode and a second electrode formed parallel to each other along a second direction crossing the first direction on the second substrate, and the first electrode A dielectric layer formed on the second substrate while covering an electrode and the second electrode, wherein each of the first electrode and the second electrode includes a transparent electrode formed on the second substrate and a transparent electrode formed on the transparent electrode; A bus electrode may be included. The bus electrode may include a black layer and a white layer, and the black layer may be formed of a plurality of layers.

The black layer may be formed with the white layer interposed therebetween. The black layer may include a first black layer formed on the transparent electrode and a second black layer formed on the white layer.

The first black layer and the second black layer may have the same width along the first direction.

The first black layer, the second black layer, and the white layer may have the same width along the first direction.

The partition wall is formed to extend in the first direction and is arranged in parallel with each other while maintaining a predetermined interval along the second direction, and the second direction between the first partition members. It may be formed along the length, and may include second partition wall members arranged in parallel with each other while maintaining a predetermined interval in the first direction.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like elements throughout the specification.

1 is a perspective view schematically illustrating an exploded view of a plasma display panel according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.

Referring to these drawings, the plasma display panel according to the exemplary embodiment is disposed on the first substrate (hereinafter referred to as a "back substrate") 10 and the second substrate which are disposed to face each other at predetermined intervals. (Hereinafter referred to as "front substrate") 20 and partition walls 16 provided between the substrates 10 and 20. The partition 16 is formed at a predetermined height between the rear substrate 10 and the front substrate 20 to partition the plurality of discharge cells 17. The discharge cells 17 are filled with a discharge gas (for example, a mixed gas including neon (Ne) and xenon (Xe)) so as to generate vacuum ultraviolet rays by gas discharge. The discharge cells 17 absorb the vacuum ultraviolet rays and display visible light. A phosphor layer 19 emitting light is provided.

The plasma display panel includes an address electrode 11 and a first electrode (hereinafter referred to as a “holding electrode”) corresponding to each discharge cell 17 between the rear substrate 10 and the front substrate 20 in order to realize an image by gas discharge. 31 and a second electrode 32 (hereinafter referred to as "scan electrode").

As an example, the address electrode 11 is formed along the first direction (y-axis direction in the drawing) on the inner surface of the back substrate 10 to form discharge cells 17 adjacent to the y-axis direction. Corresponds continuously. In addition, the plurality of address electrodes 11 are arranged side by side to correspond to the discharge cells 17 adjacent to each other in a second direction (the x-axis direction in the drawing) that crosses the y-axis direction.

The address electrodes 11 are covered with a dielectric layer 13 covering the inner surface of the back substrate 10 as described above. The dielectric layer 13 prevents cations or electrons from directly colliding with the address electrode 11 during discharge, thereby preventing damage to the address electrode 11, and also forms and accumulates wall charges. Since the address electrode 11 is disposed on the rear substrate 10 and does not prevent the visible light from being irradiated forward, the address electrode 11 may be formed as an opaque electrode. That is, the address electrode 11 may be formed of a metal electrode having excellent conductance.

The partition 16 is actually provided on the dielectric layer 13 to partition the discharge cells 17. The partition 16 includes first partition members 16a extending in the y-axis direction and second partition members 16b extending in the x-axis direction between the first partition members 16a. In addition, the discharge cells 17 are formed in a matrix structure.

In addition, the partition wall may be formed of first partition wall members extending in the y-axis direction to form discharge cells in a stripe structure (not shown). That is, the discharge cells form a structure that is open along the y-axis direction.

In this embodiment, the partition wall 16 forming the discharge cells 17 in a matrix structure is illustrated. In this state, when the second partition wall members 16b are removed, the partition wall structure is formed by the first partition wall members 16a. Discharge cells are formed. Therefore, a separate illustration of the discharge cells of the stripe structure is omitted here.

The phosphor layer 19 formed in each of the discharge cells 17 is coated with a phosphor paste on the side surface of the barrier rib 16 and the surface of the dielectric layer 13 positioned between the barrier ribs 16 and dried and It is formed by baking.

The phosphor layer 19 is formed of phosphors of the same color in the discharge cells 17 formed along the y-axis direction. In addition, the phosphor layer 19 is repeatedly formed by the phosphors of red (R), green (G), and blue (B) in the discharge cells 17 repeatedly arranged along the x-axis direction.

On the other hand, the sustain electrode 31 and the scanning electrode 32 are provided on the inner surface of the front substrate 20, the surface discharge structure corresponding to each discharge cell 17 to cause gas discharge in the discharge cells 17 To form. Referring to FIG. 3, the sustain electrode 31 and the scan electrode 32 extend in the x-axis direction crossing the address electrode 11.

Each of the sustain electrode 31 and the scan electrode 32 includes transparent electrodes 31a and 32a for generating a discharge and bus electrodes 31b and 32b for applying a voltage signal to the transparent electrodes 31a and 32a, respectively. Is formed. The transparent electrodes 31 a and 32 a are portions which cause surface discharge inside the discharge cell 17 and are formed of a transparent material (for example, indium tin oxide (ITO)) to secure the aperture ratio of the discharge cell 17. The bus electrodes 31b and 32b are formed of a metal material having excellent electrical conductivity to compensate for the high electrical resistance of the transparent electrodes 31a and 32a.

The transparent electrodes 31a and 32a form surface discharge structures with each of the widths W31 and W32 from the outer edge of the discharge cell 17 along the y-axis direction, and form a center portion of each discharge cell 17. Discharge gap G is formed. The bus electrodes 31b and 32b are disposed on the transparent electrodes 31a and 32a, respectively, and extend in the x-axis direction at the outside of the discharge cell 17. Therefore, when the voltage signal is applied to the bus electrodes 31b and 32b, the voltage signal is applied to each of the transparent electrodes 31a and 32a connected to the bus electrodes 31b and 32b.

In addition, the transparent electrodes may be connected together in the x-axis direction to cause discharge in each of the discharge cells (not shown).

Referring back to FIGS. 1 and 2, the sustain electrode 31 and the scan electrode 32 correspond to the discharge cells 17 while crossing the address electrodes 11, and face each other to the dielectric layer 21. Covered. The dielectric layer 21 forms and accumulates wall charges during discharge while protecting the sustain electrode 31 and the scan electrode 32 from gas discharge.

This dielectric layer 21 is covered with a protective film 23. For example, the protective film 23 protects the dielectric layer 21 and increases the amount of secondary electrons emitted during discharge.

In the plasma display panel driving, a reset discharge is generated by a reset pulse applied to the scan electrode 31 in the reset period, and a scan pulse applied to the scan electrode 32 in the scan period (addressing period) following the reset period. The address discharge is caused by the address pulse applied to the address electrode 11, and then the sustain discharge is caused by the sustain pulse applied to the sustain electrode 31 and the scan electrode 32 in the sustain period.

The sustain electrode 31 and the scan electrode 32 serve as electrodes for applying sustain pulses required for sustain discharge, and the scan electrodes 32 serve as electrodes for applying reset pulses and scan pulses, and the address electrodes. Reference numeral 11 serves as an electrode for applying an address pulse. The sustain electrode 32, the scan electrode 32, and the address electrode 11 may differ in their roles according to voltage waveforms applied to the sustain electrodes 32, the scan electrodes 32, and the address electrodes 11, and are not necessarily limited to these roles.

The plasma display panel selects a discharge cell 17 to be turned on by the address discharge due to the interaction between the address electrode 11 and the scan electrode 32, and the interaction between the sustain electrode 31 and the scan electrode 32. The selected discharge cell 17 is driven by sustain discharge, thereby realizing an image.

On the other hand, the plasma display panel of this embodiment is formed so as to improve the black portion and improve the clear room contrast. To this end, the plasma display panel includes structures of the modified bus electrodes 31b and 32b.

Referring to FIG. 2 as an example, the bus electrode 31b of the sustain electrode 31 includes a white layer 131 and a black layer 231, and the bus electrode 32b of the scan electrode 32 is white. It is formed including the layer 132 and the black layer 232. The black layers 231 and 232 are each formed of a plurality of layers.

In addition, in the bus electrode 31b of the sustain electrode 31, the black layer 231 is formed with the white layer 131 interposed therebetween. In the bus electrode 32b of the scan electrode 32, the black layer 232 is formed with the white layer 132 interposed therebetween.

Each of the black layers 231 and 232 may be formed of two layers, three layers, or more. In this embodiment, black layers 231 and 232 formed of two layers are illustrated.

Referring to this, in the bus electrode 31b of the sustain electrode 31, the black layer 231 is formed of the first black layer 231c formed on the transparent electrode 31a and the first layer formed on the white layer 131. Two black layers 231d.

In this case, the second black layer 231d is formed with the same area as the first black layer 231c in the area parallel to the plane of the front substrate 20 (xy direction). That is, the bus electrode 31b improves the black portion by the second black layer 231d while forming the area of the first black layer 231c in the same area as before (see FIG. 4).

Since the second black layer 231d is formed on the white layer 131, the area where the white layer 131 is in contact with the dielectric layer 21 is reduced. Therefore, a phenomenon in which the white layer 131 is caused by an ion exchange reaction with the dielectric layer 21, that is, a yellowing phenomenon may be reduced.

In addition, in the bus electrode 32b of the scan electrode 32, the black layer 232 includes a first black layer 232c formed on the transparent electrode 32a and a second black layer formed on the white layer 132. (232d).

In this case, the second black layer 232d is formed in the same area as the first black layer 232c in the area parallel to the plane of the front substrate 20 (xy direction). That is, the bus electrode 32b improves the black portion by the second black layer 232d while forming the area of the first black layer 232c in the same area as the conventional one (see FIG. 4).

Since the second black layer 232d is formed on the white layer 132, the area where the white layer 132 contacts the dielectric layer 21 is reduced. Therefore, a phenomenon in which the white layer 132 is caused by an ion exchange reaction with the dielectric layer 21, that is, a yellowing phenomenon may be reduced.

That is, in the bus electrode 31b of the sustain electrode 31, the first black layer 231c and the second black layer 231d have the same width (the size in the y-axis direction) along the y-axis direction. The first black layer 231c, the second black layer 231d, and the white layer 131 have the same width along the y-axis direction.

In addition, in the bus electrode 32b of the scan electrode 32, the first black layer 232c and the second black layer 232d have the same width along the y-axis direction. The first black layer 232c, the second black layer 232d, and the white layer 132 have the same width along the y-axis direction.

Referring to FIG. 4, the bus electrode 32b of the scan electrode 32 absorbs front external light BR1 irradiated toward the front substrate 20 in front of the bus electrode 32b. Since the sustain electrode 31 has the same effect, the description of the bus electrode 32b of the sustain electrode 31 is omitted.

In addition, the second black layer 232d having the same width as the first black layer 232c further absorbs the external light LR2 irradiated toward the front substrate 20 from the front side of the bus electrode 32b.

That is, the second black layer 232d maintains the area of the black layer (corresponding to the area of the first black layer 132c) with respect to the front substrate 20 of the bus electrode 32b while maintaining the area of the black layer 232d. Raises black rate.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

As described above, according to the plasma display panel according to the present invention, each of the first and second electrodes is formed of a transparent electrode and a bus electrode, and the bus electrode is formed of a white layer and a plurality of black layers. It has the effect of improving the black portion rate while maintaining the clear room contrast.

Claims (6)

A first substrate and a second substrate spaced apart from each other; Barrier ribs disposed between the substrates to partition discharge cells; A phosphor layer formed in the discharge cell; An address electrode formed in the first substrate along the first direction; First and second electrodes formed parallel to each other along a second direction crossing the first direction on the second substrate; And A dielectric layer formed on the second substrate while covering the first electrode and the second electrode, Each of the first electrode and the second electrode, A transparent electrode formed on the second substrate; A bus electrode formed on the transparent electrode, The bus electrode, Including black and white layers, And the black layer is formed of a plurality of layers. According to claim 1, And the black layer is formed with the white layer interposed therebetween. The method of claim 2, The black layer, A first black layer formed on the transparent electrode; And a second black layer formed on the white layer. The method of claim 3, wherein And the first black layer and the second black layer have the same width along the first direction. The method of claim 4, wherein And the first black layer, the second black layer, and the white layer have the same width along the first direction. According to claim 1, The partition wall, First barrier members formed to extend in the first direction and disposed in parallel with each other while maintaining a predetermined interval in the second direction; And And second partition walls formed between the first partition members in the second direction, the second partition members being disposed parallel to each other while maintaining a predetermined distance along the first direction.

Images