KR100603378B1 - Plasma display panel - Google Patents

Abstract

The present invention has a purpose to provide a plasma display panel having a structure that prevents permanent afterimages due to breakage of the protective film during the sustain discharge, in order to achieve this object, the present invention, the front surface disposed to face each other Substrate and back substrate; A partition wall disposed between the front substrate and the rear substrate to partition the discharge cells together with the front substrate and the rear substrate; X electrodes and Y electrodes extending side by side in one direction for each discharge cell under the front substrate; A first dielectric layer covering the X and Y electrodes and having a thin thickness so as to be far from a gap between the X electrode and the Y electrode; A protective film covering the first dielectric layer; A plurality of address electrodes extending to intersect the X and Y electrodes for each discharge cell; A second dielectric layer covering the address electrode; A phosphor layer disposed in the discharge cell; And it provides a plasma display panel having a discharge gas filled in the discharge cell.

Description

Plasma display panel {Plasma display panel}

1 is a cross-sectional view showing one discharge cell of a conventional plasma display panel;

2 is an exploded perspective view of a plasma display panel according to an embodiment of the present invention;

3 is a cross-sectional view taken along line III-III of FIG. 2.

<Brief description of the major symbols in the drawings>

100: plasma display panel 112: front substrate

113: sustain electrode pair 114: X electrode

114 ': End of the X electrode gap opposite side 114 ": End of the X electrode gap opposite side

114a: transparent X electrode 114b: bus X electrode

115: Y electrode 115 ': Y electrode gap side end

115 ": Y electrode gap opposite end 115a: Transparent Y electrode

115b: bus Y electrode 118: first dielectric layer

119: protective film 122: rear substrate

125: address electrode 128: second dielectric layer

131: partition 135: phosphor layer

150: discharge cell G: gap between X electrode and Y electrode

D1: thickness of the first dielectric layer at the center of the discharge cell

D2: thickness of the first dielectric layer at the end of the discharge cell

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, each electrode is formed on one surface of substrates facing each other, and a predetermined power is applied while a discharge gas is injected into the spaces between the substrates. The present invention relates to a plasma display panel that realizes an image by using light emitted by ultraviolet rays generated by the ultraviolet rays.

The plasma display panel may be classified into a direct current type and an alternating current type according to a discharge type. In the DC plasma display panel, the electrodes are exposed to the discharge space, so that the movement of charged particles is made directly between the corresponding electrodes. In the AC plasma display panel, at least one electrode is covered with a dielectric layer, and the direct charge of the corresponding electrodes The discharge is performed by the electric field of the wall charge instead of the movement.

1 is a cross-sectional view showing a unit pixel inside a conventional AC plasma display panel. Referring to FIG. 1, a typical plasma display panel 10 includes an upper plate 11 for displaying an image to a user and a lower plate 21 disposed to face the upper plate.

The top plate 11 typically includes a front substrate 12 and sustain electrode pairs 13. The front substrate 12 is usually a glass plate, and on the bottom thereof, sustain electrode pairs 13 arranged in pairs per unit pixel are arranged. The sustain electrode pairs 13 are divided into an X electrode 14 and a Y electrode 15. The X electrode 14 is composed of a transparent X electrode 14a and a bus X electrode 14b formed side by side on one side of the transparent X electrode, and the Y electrode 15 is formed of the transparent Y electrode 15a and the transparent Y electrode. It consists of a bus Y electrode 15b formed side by side on one side.

The lower plate 21 includes a rear substrate 22 and a plurality of address electrodes 23. The rear substrate 22 is disposed to face the front substrate 12, and the address electrode 23 is disposed on the upper surface of the rear substrate so as to intersect the sustain electrode pairs 13 of the front substrate 12.

The front dielectric layer 18 and the rear dielectric layer 28 are formed on the bottom surface of the front substrate provided with the sustain electrode pairs 13 and the top surface of the back substrate provided with the address electrode 23, respectively. A protective film 19 made of MgO is generally formed on the front dielectric layer 18, and the discharge layer is maintained on the rear dielectric layer 28 to prevent electro-optic crosstalk between the discharge cells and to partition the discharge cells. A plurality of partitions 31 are formed.

Red, green, and blue phosphors 35 are coated on both side surfaces of the partition wall 31 and the upper surface of the rear dielectric layer 28 in which the partition wall 31 is not formed.

When the sustain discharge occurs between the X electrode 14 and the Y electrode 15 in the plasma display panel 10 having such a structure, the X electrode 14 is disposed at a portion disposed close to the Y electrode 15. The amount of discharge becomes larger than the portion disposed relatively far from the Y electrode 15. At the same time, the amount of discharge at the portion disposed close to the X electrode 14 also becomes larger than the portion disposed relatively far from the X electrode 14. When the amount of sustain discharge is excessively increased, ions causing sustain discharge and ion sputtering occur with the front dielectric layer 18.

Therefore, the excessive amount of the sustain discharge in the adjacent portions of the X electrode 14 and the Y electrode 15, that is, the gap portion, causes the protection film 19 corresponding to this portion to be relatively damaged.

However, in order to increase the luminance, the front substrate 12 has a transparent X electrode 14a and a transparent Y electrode 15a made of ITO in the center of the discharge cell. The protective film is visually seen through the transparent electrode. There is a problem that damage is observed.

On the other hand, the protective film 19 usually protects the front dielectric layer 18 from ion sputtering and has a characteristic of high secondary electron generation coefficient to serve to lower the holding voltage and driving voltage. And since the protective film is damaged in the adjacent portions of the Y electrode 15, in particular, the luminous efficiency is reduced in this portion, the permanent afterimage occurs in the plasma display panel 10 due to such a reduction in the luminous efficiency There is this.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a plasma display panel having a structure which prevents permanent afterimages from occurring due to breakage of a protective film during sustain discharge.

Plasma display panel according to a preferred embodiment of the present invention for achieving the above object is:

A front substrate and a rear substrate disposed to face each other;

A partition wall disposed between the front substrate and the rear substrate to partition discharge cells together with the front substrate and the rear substrate;

X electrodes and Y electrodes extending side by side in one direction for each of the discharge cells below the front substrate;

A first dielectric layer covering the X and Y electrodes and having a thin thickness so as to be far from a gap between the X and Y electrodes;

A protective film covering the first dielectric layer;

A plurality of address electrodes extending to intersect the X and Y electrodes for each discharge cell;

A second dielectric layer covering the address electrode; A phosphor layer disposed in the discharge cell; And

And a discharge gas filled in the discharge cell.

It is preferable that the thickness of the first dielectric layer gradually decreases from the center portion to the end portion of the discharge cell. In this case, the thickness of the first dielectric layer at the center portion of the discharge cell is greater than or equal to 40 µm and the first portion at the end portion of the discharge cell. More preferably, the dielectric layer thickness is at least 25 μm or more.

The address electrode may further include a second dielectric layer disposed on an upper surface of the rear substrate and formed on the rear substrate to cover the upper surface of the rear substrate together with the address electrode.

The X electrode may include: a transparent X electrode disposed in one direction on a lower surface of the front substrate for each discharge cell; A bus X electrode disposed on the bottom surface of the discharge cell of the transparent X electrode to compensate for electrode line resistance of the transparent X electrodes, and the Y electrode includes: the transparent X electrode on the bottom surface of the front substrate for each discharge cell; Transparent Y electrodes arranged side by side; A bus Y electrode may be provided on the bottom surface of the discharge cell of the transparent Y electrode to compensate the electrode line resistance of the transparent Y electrodes.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 2 and 3, the plasma display panel 100 according to an exemplary embodiment of the present invention includes a front substrate 112, a rear substrate 122, sustain electrode pairs 113, and a first dielectric layer 118. ), A phosphor layer 135, address electrodes 125, barrier ribs 131, and a discharge gas (not shown).

The transparent front substrate 112 is disposed in parallel with the rear substrate 122 so that the visible light in the discharge cell passes through to project the image. The front substrate 112 and the rear substrate 122 partition one discharge cell 150 together with the partition wall 135 to be described later.

The front substrate 112 is made of a material having good light transmittance, such as glass, through which visible light is emitted to the outside. The back substrate 122 is also usually made of a material mainly composed of glass.

Under the front substrate 112, the sustain electrode pairs 113 formed by pairing the X electrode 114 and the Y electrode 115 are formed.

Each of the discharge cells 150 is disposed such that the address electrode 123 extends in a direction crossing the sustain electrode pairs 113. In this case, the address electrodes 123 may be disposed on the upper side of the rear substrate 122 opposite to the surface on which the sustain electrode pair 113 of the front substrate 112 is disposed. The address electrode 123 functions to generate an address discharge together with the Y electrode 115.

In this case, the sustain electrode pairs 113 extend across the subpixels in one direction, and the address electrodes 123 extend across the discharge cells to intersect the sustain electrode pairs 113. .

The X electrode 114 is usually composed of a transparent X electrode 114a and a bus X electrode 114b, and the Y electrode 115 is usually composed of a transparent Y electrode 115a and a bus Y electrode 115b. The transparent X electrode 114a and the transparent Y electrode 115a are transparent electrodes made of indium tin oxide (ITO), and the bus X electrode 114b and the bus Y electrode 115b are the transparent X electrode 114a and the transparent Y. Is formed on the lower surface of the electrode 115a to reduce the electrode line resistance of the transparent X electrode 114a and the transparent Y electrode 115a, for example, made of a metal material. The present invention is not limited thereto, and the X electrode 114 and the Y electrode 115 may be formed of only the transparent X electrode 114a and the transparent Y electrode 115a. Alternatively, the X electrode 114 may be formed. And the Y electrode 115 may include only the bus X electrode 114b and the bus Y electrode 115b.

The first dielectric layer 118 is disposed below the front substrate 112 provided with the sustain electrode pairs 113 to fill the X electrode 114, the Y electrode 115, and the front substrate 112. In addition, the address electrode 123 and the back substrate 122 are preferably covered by the second dielectric layer 128.

Each of the first dielectric layer 118 and the second dielectric layer 128 may induce charge while preventing cations or electrons from colliding with the sustain electrode pair 113 and the address electrode 123 during discharge, thereby damaging the electrodes. Formed from a dielectric. The first dielectric layer 118 has a thin thickness so as to be far from the gap between the X electrode and the Y electrode.

A protective film 119 is preferably formed on the bottom surface of the first dielectric layer 118. The protective film 119 serves to prevent damage to the dielectric layer due to the sputtering of plasma particles and to lower the discharge voltage and the sustain voltage due to secondary electron emission. In general, an MgO film by vapor deposition is used.

A partition wall 131 is disposed between the front substrate 112 and the rear substrate 122. The barrier rib partitions the discharge cell 150 together with the front substrate 112 and the rear substrate 122, and prevents an erroneous discharge between the discharge cells 150.

The phosphor layer 135 is coated in the discharge cell 150. The phosphor layer 135 functions to excite visible light and emit it to the outside as it collides with the ultraviolet light generated by the sustain discharge.

The phosphor layer 135 may be roughly divided into a red phosphor layer, a green phosphor layer, and a blue phosphor layer according to the color of visible light emitted. The red phosphor layer is formed to include phosphors such as Y (V, P) O 4: Eu, and the like, and the green phosphor layer is formed to include phosphors such as Zn 2 SiO 4: Mn, YBO 3: Tb, and the blue phosphor layer is BAM: Eu. It may be formed including a phosphor such as.

The discharge gas charged in the discharge cell 150 uses a penning mixture such as Xe-Ne, Xe-He, and Xe-Ne-He. The reason why Xe is used as the main discharge gas is that because Xe is a chemically stable inert gas, it is not dissociated due to discharge, but because the atomic number is large, the excitation voltage is lowered and the wavelength of light emitted is increased. to be. The reason for using He or Ne as a buffer gas is because the voltage reduction effect due to the panning effect due to Xe and the sputtering effect due to the high pressure are reduced. The main discharge gas may be a rare gas such as Kr in addition to Xe.

The operation of the plasma display panel having such a structure is as follows. When a predetermined voltage is applied to the address electrode 123 and the Y electrode 115, a discharge cell for emitting light is selected, and an address discharge occurs between the two electrodes 115 and 123, so that wall charges are formed on the first dielectric layer 118. Is charged. Thereafter, when a predetermined voltage is alternately applied between the X electrode 114 and the Y electrode 115, wall charges move between the two electrodes 114 and 115, causing the discharge gas to cause a sustain discharge. The discharge gas generates ultraviolet rays, and the generated ultraviolet rays excite the phosphor 135 to form an image.

Referring to the operation of the plasma display panel in more detail, first, when the discharge start voltage of 150V to 300V is supplied to the sustain electrode pair 113 and the address electrode 123, wall charges are formed on the inner surface of the corresponding discharge space.

Thereafter, when the address discharge voltage is supplied to the Y electrode 115 and the address electrode 123 in the discharge cell in which light emission is selected, an address discharge occurs between the Y electrode 115 and the address electrode 123. Thereafter, when the sustain discharge voltage of 150 V or more is supplied to the Y electrode 115 and the X electrode 114 alternately, sustain discharge occurs and light emission of any discharge cell is maintained for a predetermined time. That is, an electric field is generated inside the discharge cell to accelerate the trace electrons in the discharge gas, and the accelerated electrons and the neutral particles in the gas collide with each other to be ionized into electrons and ions, and another collision between the ionized electrons and the neutral particles. Neutral particles are ionized into electrons and ions at a rapid rate, and the discharge gas becomes plasma, and vacuum ultraviolet (UV) is generated.

The generated ultraviolet rays excite the phosphor 135 to generate visible light, and when the generated visible light is emitted to the outside through the front substrate 112, the external light may emit light of an arbitrary discharge cell, that is, image display. Will be.

 As described above, the protective film 119 is formed at the center of the discharge cell due to a large amount of sustain discharge occurring in the gap G between the transparent X electrode 114a and the transparent Y electrode 115a which are formed side by side in one discharge cell 150. ) (F; see FIG. 1) is generated, and as a result, it is necessary to prevent the occurrence of permanent afterimages due to a decrease in luminous efficiency at the center of the discharge cell.

Therefore, in the present invention, the first dielectric layer 118 has a thin thickness so as to move away from the gap G between the X electrode 114 and the Y electrode 115. As a result, no strong sustain discharge occurs in this gap, and damage to the protective film due to ion sputtering can be reduced.

That is, the capacity 150 between the electrodes is proportional to the area A and the dielectric constant epsilon of the electrode and is inversely proportional to the separation distance d between the electrodes, as in the formula C = ε · A / d. Therefore, as the thickness of the dielectric in the gap G between the X electrode and the Y electrode increases, the separation distance between the gap side end 114 'of the X electrode 114 and the gap side end 115' of the Y electrode 115 is increased. Has an effect of lengthening, and as a result, the sustain discharge of the gap G portion between the X electrode 114 and the Y electrode 115 occurs small.

On the other hand, in the gap opposite end 114 "of the X electrode 114 and the gap opposite end 115" of the Y electrode 115, the dielectric is thin and thereby the discharge distance is shortened, thereby increasing the capacity and increasing the wall charge. Is accumulated a lot, thereby increasing the ratio involved in the discharge. Therefore, even if the discharge distance is long, the effect of participating in the discharge is increased at the gap opposite end 114 "of the X electrode 114 and the gap opposite end 115" of the Y electrode 115, so that the efficiency of the entire plasma display panel is increased. Increases.

On the other hand, since the gap G between the X electrode and the Y electrode is generally located at the center of the discharge cell, the first dielectric layer 118 has a thickness from the center of the discharge cell 118 'to the end 118 ". It is desirable to become thinner and thinner.

In this case, the thickness D1 of the first dielectric layer 118 at the center of the discharge cell may be large in order to generate excessive wall charges in the front dielectric layer while preventing excessive increase of the discharge current to increase the efficiency of the panel. The thickness of the first dielectric layer 118 ″ at the end of the discharge cell is preferably at least 25 μm.

According to the plasma display panel of the present invention having the structure as described above, since the discharge is not strong at the center of the discharge cell, which is the gap portion between the transparent electrodes, it is possible to prevent the protective film from being damaged by the sputtering of ions, thereby preventing the occurrence of permanent afterimages. Can be prevented or minimized.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Could be. Accordingly, the true scope of protection of the invention should be defined only by the appended claims.

Claims (5)

A front substrate and a rear substrate disposed to face each other; A partition wall disposed between the front substrate and the rear substrate to partition discharge cells together with the front substrate and the rear substrate; X electrodes and Y electrodes extending side by side in one direction with a gap for each of the discharge cells below the front substrate; A first dielectric layer covering the X and Y electrodes and having a thin thickness so as to move away from a gap between the X and Y electrodes; A protective film covering the first dielectric layer; A plurality of address electrodes extending to intersect the X and Y electrodes for each discharge cell; A second dielectric layer covering the address electrode; A phosphor layer disposed in the discharge cell; And And a discharge gas filled in the discharge cells. The method of claim 1, And the thickness of the first dielectric layer becomes thinner from the center portion to the end portion of the discharge cell. The method of claim 1, And the thickness of the first dielectric layer at the center of the discharge cell is at most 40 μm or less, and the thickness of the first dielectric layer at the end of the discharge cell is at least 25 μm or more. The method of claim 1, The address electrode is disposed on the top surface of the back substrate, And a second dielectric layer formed on the rear substrate to cover the upper surface of the rear substrate together with the address electrode. The method of claim 1, The X electrode includes: a transparent X electrode disposed in one direction on a lower surface of the front substrate for each discharge cell; A bus X electrode disposed on the bottom surface of the discharge cell of the transparent X electrode to compensate the electrode line resistance of the transparent X electrodes, The Y electrode includes: a transparent Y electrode disposed parallel to the transparent X electrode on the lower surface of the front substrate for each discharge cell; And a bus Y electrode disposed under the discharge cell end of the transparent Y electrode to compensate for electrode line resistance of the transparent Y electrodes.

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