JP2010080311A - Plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a crack from being generated in a protective layer of a PDF (Plasma Display Panel) having a dielectric layer formed by a silica particle. <P>SOLUTION: The PDP includes paired line electrodes X, Y formed on a back face of a front face glass substrate 1, the dielectric layer 2 for covering the paired line electrodes X, Y, and the protective layer 3 for covering a backface of the dielectric layer 2, wherein the dielectric layer 2 is formed of the silica particle, and the protective layer 3 is formed by applying, on the dielectric layer 2, a metal crystalline particle of MgO, La<SB>2</SB>O<SB>3</SB>, SrO, CaO, (Sr, Ca)O or the like which is a secondary electron emitting material. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to the structure of a plasma display panel.

  In a plasma display panel (hereinafter referred to as PDP), generally, a plurality of row electrode pairs are formed on the back surface of a front glass substrate, and column electrodes are arranged on the back glass substrate facing the front glass substrate through a discharge space. Discharge cells formed in a matrix form are formed in discharge spaces at portions where the row electrode pairs and the column electrodes intersect with each other, and one row electrode of the row electrode pair is formed in the discharge cell. A discharge is generated between the column electrodes and between the row electrodes of the pair of row electrodes, and the phosphor layers of the three primary colors of red, green, and blue formed in each discharge cell emit light, thereby forming an image by matrix display. It is the composition which performs.

  The PDP row electrode pair having such a configuration is covered with a dielectric layer formed on the back surface of the front glass substrate, and this dielectric layer is further covered with a protective layer formed on the inner surface thereof. .

  This dielectric layer insulates and protects the pair of row electrodes and accumulates surface charges (wall charges) to provide a discharge generation function and a discharge limiting function. The protective layer is a protective function for the dielectric layer. And a function of emitting secondary electrons into the discharge cell.

  Generally, a dielectric glass having a low melting point is used for the dielectric layer of the PDP. However, in order to reduce the power consumption of the PDP and improve the light emission efficiency, this dielectric layer has conventionally had a low relative dielectric constant. A PDP formed by concentrating silica particles has been proposed (see, for example, Patent Document 1).

  However, in this conventional PDP, the protective layer is formed of magnesium oxide (MgO) by a vapor deposition method or a sputtering method on the dielectric layer formed of silica particles, so that the dielectric layer and the protective layer are in close contact with each other. The force is weakened, and in the manufacturing process, the protective layer is heated after it is formed, so that expansion and contraction may occur, so that a minute crack may occur in the entire protective layer.

When the heating process for the protective layer is repeated during the manufacturing process of the PDP, the number of cracks generated in the protective layer increases and the number of the cracks increases. There is a risk of causing problems such as a decrease in the withstand voltage performance of the dielectric layer and an occurrence of abnormal discharge when the PDP is driven.
FIG. 1 is an enlarged partial photograph of the front glass substrate after forming the protective layer of the conventional PDP taken from the back side, and it can be seen that a crack has occurred in the protective layer.

  In FIG. 1, bus electrodes extend in the vertical direction in the vertical direction, and transparent electrodes have a substantially T-shape connected to each bus electrode at equally spaced positions. The bus electrodes and the transparent electrodes constitute row electrodes.

JP 2007-287559 A

  An object of the present invention is to solve the problems of the conventional PDP as described above.

  In order to achieve the above object, the PDP according to the present invention has a discharge electrode formed on the back surface of the front substrate, a dielectric layer covering the discharge electrode, and a dielectric layer formed on the back surface of the dielectric layer. In the PDP having a protective layer covering the back surface of the substrate, the dielectric layer is formed of silica particles, and the protective layer is coated with crystal particles that are secondary electron emission materials on the dielectric layer. It is characterized by being formed by.

  In the present invention, a discharge electrode and a dielectric layer covering the discharge electrode are formed on the back surface of the front glass substrate, and a protective layer covering the back surface of the dielectric layer is formed on the back surface of the dielectric layer. A PDP in which the dielectric layer is formed of silica particles and the protective layer is formed by applying crystal particles as a secondary electron emission material on the dielectric layer is the best embodiment.

  In the PDP of the above embodiment, since the dielectric layer is formed of silica particles, the capacitance of the dielectric layer is reduced and the generation of reactive power is suppressed as compared with the conventional PDP. It is possible to improve luminous efficiency and reduce power consumption.

Furthermore, since both the dielectric layer and the protective layer are formed of an aggregate of particles, the resilience of the resilience to expansion and contraction when the protective layer is heated in the PDP manufacturing process is increased, and The crystal particles forming the protective layer and the silica particles forming the dielectric layer are fitted into the missing portions of both layers, thereby preventing the protective layer from being cracked.
This makes it possible to reduce power consumption and improve voltage resistance as compared with the conventional PDP, and to prevent occurrence of abnormal discharge.
In the PDP of the above embodiment, it is preferable that the silica particles have a particle size of 5 to 40 nm.

This is because if the particle size of the silica particles is smaller than 5 nm, the dielectric layer may crack, and as a result, the voltage resistance may not be sufficiently obtained. This is because the transmittance of the dielectric layer deteriorates as the value increases.
In the PDP of the above embodiment, the dielectric layer is preferably formed to a thickness of 5 to 20 μm.

This is because if the thickness of the dielectric layer is less than 5 μm, the voltage resistance may not be sufficiently obtained, and if the thickness is greater than 20 μm, the transmittance of the dielectric layer may deteriorate, This is because cracks may occur in the layer.
In the PDP of the above embodiment, it is preferable that the crystal particles have a particle diameter of 5 to 100 nm with respect to silica particles having a particle diameter of 5 to 40 nm.

This is because, when the particle size of the crystal particles forming the protective layer is too small relative to the particle size of the silica particles forming the dielectric layer, the protective layer becomes too dense and the protective layer formed by vapor deposition The protective layer may crack when heated in the PDP manufacturing process, and when the particle size is larger than 100 nm, the silica particles forming the dielectric layer are protected. This is because the transmittance is deteriorated by the influence of optical scattering caused by the influence of both of the metal crystal particles forming the layer.
In the PDP of the above embodiment, it is preferable that the protective layer has a thickness of 0.5 to 10 μm.

  This is because when the thickness of the protective layer is less than 0.5 μm, the sputtering resistance against discharge generated in the discharge space during PDP driving is deteriorated, the product life of the PDP is shortened, and when it is greater than 10 μm, This is because the transmittance of the protective layer is lowered.

In the PDP of the above embodiment, the protective layer is formed of crystal particles of metal oxide including at least one type of crystal particles of MgO, La ₂ O ₃ , SrO, CaO, (Sr, Ca) O. Is preferable.

  FIG. 2 is a cross-sectional view showing an example of the embodiment of the PDP according to the present invention.

  In FIG. 2, a plurality of row electrode pairs (X, Y) extend in the row direction (perpendicular to the plane of FIG. 2) on the back surface of the front glass substrate 1 constituting the panel surface and in the column direction (see FIG. 2). 2 in the left-right direction).

The row electrodes X and Y constituting the row electrode pair (X, Y) are respectively directed to the metal bus electrodes Xa, Ya and the counterpart row electrode side paired with the bus electrodes Xa, Ya. And transparent electrodes Xb and Yb that are opposed to each other via a discharge gap g.
A dielectric layer 2 is further formed on the back surface of the front glass substrate 1, and the row electrode pair (X, Y) is covered with the dielectric layer 2.
A protective layer (metal oxide film) 3 is formed on the back surface of the dielectric layer 2, and the entire back surface of the dielectric layer 2 is covered with the protective layer 3.
The configurations of the dielectric layer 2 and the protective layer 3 will be described in detail later.

On the surface (inner surface) of the rear glass substrate 4 facing the front glass substrate 1 through the discharge space S, the row electrode pair (X, Y) is disposed in the discharge space S. A plurality of column electrodes D, each forming a discharge cell, extend in the column direction and are arranged in parallel in the row direction.
A column electrode protective layer 5 is further formed on the rear glass substrate 4 to cover the column electrode D.
On the column electrode protective layer 5, phosphor layers 6 are formed that are color-coded red, green, and blue for each discharge cell.
In the discharge space S, a discharge gas containing xenon is sealed at a required pressure.
Next, the configuration of the dielectric layer 2 will be described in detail.
The dielectric layer 2 is composed of a nanosilica film formed of silica particles having a particle size of 5 to 40 nm.

This nanosilica film is formed by a colloidal silica aqueous solution (a colloidal solution in which nano-level silica particles are dispersed) containing about 10 percent solids (silica particles) in polyvinyl alcohol and having a viscosity of about 100 cP. The nanosilica film is formed by firing to form a porous silica dielectric layer having a relative dielectric constant of 2.6 (@ 100 kHz), a density of 60 percent, and a light transmittance of 99 percent or more.
The reason why the colloidal silica solution as described above is used to form the dielectric layer 2 is as follows.
That is, the non-dielectric constant of the dielectric glass material used as the dielectric material of the conventional PDP is about 7 to 11, while the non-dielectric constant of silica is about 4.

  When the dielectric layer is formed using the colloidal silica solution, the filling rate of the silica particles into the dielectric layer is lowered, so that the dielectric layer becomes porous, and the relative dielectric constant of the dielectric layer is 3 The following ultra-low dielectric constant is obtained.

For this reason, by forming the dielectric layer so as to reduce its thickness, generation of reactive power during PDP driving can be suppressed and power consumption can be reduced.
The reason why silica particles having a particle size of 5 to 40 nm are used for forming the dielectric layer 2 is as follows.

That is, if the particle size of the silica particles is smaller than 5 nm, the dielectric layer may be cracked. As a result, the voltage resistance may not be sufficiently obtained, and the particle size is larger than 40 nm. This is because the transmittance of the dielectric layer is deteriorated.
The silica particles forming the dielectric layer 2 do not have to have a uniform particle size, and the particle size of the silica particles may vary within the above range.
The thickness of the dielectric layer 2 is set to 5 to 20 μm, preferably 7 to 12 μm.

This is because if the thickness of the dielectric layer is less than 5 μm, the voltage resistance may not be sufficiently obtained, and if the thickness is greater than 20 μm, the transmittance of the dielectric layer may deteriorate, This is because cracks may occur in the layer.
The protective layer 3 is formed of metal crystal particles such as MgO, La2O3, SrO, CaO, (Sr, Ca) O.
The protective layer 3 is formed by using the above metal crystal particles alone or a mixture of a plurality of types of metal crystal particles.

  Then, a solvent containing metal crystal particles such as MgO crystal particles is applied on the back surface of the dielectric layer by a spray method or a printing method, and then baked to remove organic components in the solvent, A protective layer 3 made of metal crystal particles is formed.

  The metal crystal particles forming the protective layer 3 are selected to have a particle diameter of 5 to 100 nm, and the thickness of the protective layer 3 is set to 0.5 to 10 μm (preferably 1 to 5 μm).

  The metal crystal particles forming the protective layer 3 have a function as a secondary electron emission material. The reason why the particle size is set to 5 to 100 nm as described above is as follows.

  That is, when the particle size of the metal crystal particles forming the protective layer 3 is too small with respect to the particle size of the silica particles forming the dielectric layer 2, the protective layer becomes too dense and will be described in detail later. In the same manner, the protective layer formed by vapor deposition of the conventional PDP has the same structure, and there is a possibility that the protective layer may crack when heated in the PDP manufacturing process, and the particle size is larger than 100 nm. In this case, the transmittance is deteriorated due to the influence of optical scattering caused by both the silica particles forming the dielectric layer 2 and the metal crystal particles forming the protective layer 3.

  As described above, the protective layer 3 is formed of metal crystal particles having a particle size of 5 to 100 nm, thereby preventing the protective layer from cracking during heating in the manufacturing process of the PDP and forming the protective layer 3. As the protective layer 3 is made porous, the relative dielectric constant is lowered.

  Moreover, the thickness of the protective layer 3 is set to 0.5 to 10 μm because when the thickness is less than 0.5 μm, the sputtering resistance against the discharge generated in the discharge space S during PDP driving deteriorates. This is because when the product life of the PDP is shortened and becomes larger than 10 μm, the transmittance of the protective layer 3 is lowered.

  In the PDP, after a reset discharge that initializes each discharge cell, an address discharge is selectively generated between each row electrode Y and the column electrode D, and a light emitting cell (dielectric material of an opposing portion) is formed on the panel surface. Corresponding to the image data of the video signal, the discharge cell in which the wall charge is formed in the layer 2 and the non-light emitting cell (the discharge cell in which the wall charge of the opposing dielectric layer 2 is erased) correspond After the distribution, a sustain discharge is generated through the discharge gap g between the transparent electrodes Xb and Yb of the pair of row electrodes (X, Y) in each light emitting cell, and the red light in each light emitting cell. , Green and blue phosphor layers 6 emit light to form an image by matrix display.

  According to the PDP, the dielectric layer 2 is composed of a nanosilica film formed of silica particles having a particle diameter of 5 to 40 nm, so that the capacitance of the dielectric layer 2 is reduced compared to the conventional PDP. By suppressing the generation of reactive power, it is possible to improve the light emission efficiency of the PDP and reduce the power consumption.

  Further, according to the above PDP, since both the dielectric layer 2 and the protective layer 3 are formed of aggregates of fine particles (silica particles and metal crystal particles), the protective layer 3 is protected from expansion and contraction during heating. After the formation, the flexibility of the resuscitation force is increased and the metal crystal particles forming the protective layer 3 and the silica particles of the fine particles forming the dielectric layer 2 are fitted into the missing portions of both layers. The generation of cracks in the protective layer 3 is prevented.

  As a result, the PDP can reduce power consumption and voltage resistance as compared to the conventional PDP, and can prevent the occurrence of abnormal discharge.

Then, the silica particles forming the dielectric layer 2 and the metal crystal particles forming the protective layer 3 are attracted by the mutual intermolecular force at the layer interface, so that necessary adhesion between the dielectric layer 2 and the protective layer 3 is achieved. In addition, the metal crystal particles forming the protective layer 3 and the silica particles of the fine particles forming the dielectric layer 2 fit into each other in the missing portions of the particles of both layers, so that the dielectric layer 2 Repair of the mutual layer defects of the protective layer 3 is performed.
FIG. 3 is an enlarged partial photograph of the front glass substrate 1 after the formation of the protective layer 3 of the PDP according to the above embodiment taken from the back side.
It can be seen from FIG. 3 that the protective layer 3 is not cracked.

In FIG. 3, the bus electrodes Xa and Ya extend in a strip shape in the vertical direction. The bus electrodes Xa and Ya have a substantially T-shape connected to the equally spaced positions of the bus electrodes Xa and Ya. Are the transparent electrodes Xb and Yb, and the bus electrodes Xa and Ya and the transparent electrodes Xb and Yb constitute row electrodes X and Y, respectively.
FIG. 4 is a graph showing the results of the pressure resistance test performed on the PDP of the above-described embodiment in comparison with the pressure resistance test results of the conventional PDP.

  In FIG. 4, samples 1 and 2 are the above-described conventional PDPs in which the dielectric layer is formed of silica particles having a small relative dielectric constant, and the protective layer is formed of MgO by vapor deposition or sputtering, and sample 3 is The PDP is not provided with a protective layer, and Samples 4 and 5 are the PDPs of the above examples.

  The dielectric layers of Samples 1 to 5 are formed to have the same thickness by the same colloidal silica material, and the protective layers of Samples 1, 2, 4, and 5 are the same thickness of MgO. (10 μm).

From the results shown in FIG. 4, the conventional PDPs of Samples 1 and 2 have lower withstand voltage than the PDP having no protective layer of Sample 3, but the PDPs of the above examples of Samples 4 and 5 are It can be seen that the withstand voltage is higher than any of the PDPs 1 to 3.

  The PDP of the above embodiment includes a discharge electrode formed on the back surface of the front substrate, a dielectric layer covering the discharge electrode, and a protective layer formed on the back surface of the dielectric layer and covering the back surface of the dielectric layer. The dielectric layer is formed of silica particles, and the protective layer is formed by applying crystal particles as a secondary electron emission material on the dielectric layer. The PDP is a PDP of the superordinate concept.

  According to the PDP of this embodiment, since the dielectric layer is formed of silica particles, the capacitance of the dielectric layer is reduced and the generation of reactive power is suppressed compared to the conventional PDP, It is possible to improve the light emission efficiency of the PDP and reduce the power consumption.

Furthermore, since both the dielectric layer and the protective layer are formed of an aggregate of particles, the flexibility of resuscitation for expansion and contraction when the protective layer is heated in the manufacturing process of the PDP is increased. The crystal particles forming the protective layer and the silica particles forming the dielectric layer are fitted into the missing portions of both layers, thereby preventing the protective layer from being cracked.
As a result, it is possible to reduce power consumption and improve voltage resistance as compared with conventional PDPs, and to prevent occurrence of abnormal discharge.

It is the elements on larger scale which show the formation state of the protective layer of the conventional PDP. It is sectional drawing which shows the Example of PDP by this invention. It is the elements on larger scale which show the formation state of the protective layer of PDP by the Example. It is a graph which shows the result of the pressure | voltage resistant test with respect to PDP of the Example compared with the pressure | voltage resistant test result of the conventional PDP.

Explanation of symbols

1 ... Front glass substrate (front substrate)
2 ... Dielectric layer 3 ... Protective layer X, Y ... Row electrode (discharge electrode)
Xa, Ya ... bus electrode Xb, Yb ... transparent electrode

Claims (7)

A plasma display panel comprising a discharge electrode formed on the back surface of a front substrate, a dielectric layer covering the discharge electrode, and a protective layer formed on the back surface of the dielectric layer and covering the back surface of the dielectric layer In
The dielectric layer is formed of silica particles;
The protective layer is formed by applying crystal particles as a secondary electron emission material on the dielectric layer,
A plasma display panel characterized by that.   The plasma display panel according to claim 1, wherein the silica particles have a particle size of 5 to 40 nm.   The plasma display panel according to claim 1, wherein the dielectric layer is formed to a thickness of 5 to 20 μm.   The plasma display panel according to claim 2, wherein the crystal particles have a particle size of 5 to 100 nm.   The plasma display panel according to claim 1, wherein the protective layer has a thickness of 0.5 to 10 μm.   The plasma display panel according to claim 1, wherein the crystal particles are metal oxide crystal particles. The plasma display panel according to claim 6, wherein the crystal particles of the metal oxide include at least one type of crystal particles of MgO, La ₂ O ₃ , SrO, CaO, (Sr, Ca) O.