WO2012147250A1

WO2012147250A1 - Plasma display panel

Info

Publication number: WO2012147250A1
Application number: PCT/JP2012/001090
Authority: WO
Inventors: 覚河瀬; 由士行太田
Original assignee: パナソニック株式会社
Priority date: 2011-04-27
Filing date: 2012-02-20
Publication date: 2012-11-01

Abstract

This plasma display panel comprises a front surface plate, and a back surface plate disposed facing the front surface plate. The front surface plate has a display electrode and a dielectric layer covering the display electrode. The dielectric layer includes silica particles and a glass layer. The dielectric constant is 5.5 or less. The thermal expansion coefficient of the glass layer is from 79×10^-7/°C to 95×10^-7/°C. The silica particle content is from 5 vol% to 30 vol%.

Description

Plasma display panel

The technology disclosed herein relates to a plasma display panel used for a display device or the like.

Silver (Ag) is used for bus electrodes constituting display electrodes of a plasma display panel (hereinafter referred to as PDP) in order to obtain good conductivity. For the dielectric layer covering the bus electrodes, low melting point glass mainly composed of lead oxide is used. In recent years, a dielectric layer not containing a lead component has been used in consideration of the environment (for example, see Patent Document 1).

JP 2003-128430 A

The PDP includes a front plate and a back plate disposed to face the front plate. The front plate has a display electrode and a dielectric layer covering the display electrode. The dielectric layer includes silica particles and a glass layer. The thermal expansion coefficient of the glass layer is 79 × 10 ⁻⁷ / ° C. or higher and 95 × 10 ⁻⁷ / ° C. or lower. Content of the silica particle in a dielectric material layer is 5 volume% or more and 30 volume% or less. The relative dielectric constant of the dielectric layer is 5.5 or less.

FIG. 1 is a perspective view showing the structure of the PDP according to the embodiment. FIG. 2 is a schematic view showing a cross section of the front plate according to the embodiment. FIG. 3 is a diagram showing the relationship between the particle size of silica particles and the haze value.

[1. Configuration of PDP1]
The PDP 1 of the present embodiment is an AC surface discharge type PDP. As shown in FIG. 1, the PDP 1 is provided with a front plate 2 made of a front glass substrate 3 and a back plate 10 made of a back glass substrate 11 facing each other. The outer peripheral portions of the front plate 2 and the back plate 10 are hermetically sealed with a sealing material made of glass frit or the like. A discharge gas containing xenon (Xe) is sealed in the sealed discharge space inside the PDP 1 at a pressure of 55 kPa to 80 kPa.

On the front glass substrate 3, a pair of strip-shaped display electrodes 6 each composed of the scanning electrodes 4 and the sustaining electrodes 5 and a plurality of light shielding layers 7 are arranged in parallel to each other. The scanning electrode 4 is composed of a black electrode 4a and a white electrode 4b stacked on the black electrode 4a. The sustain electrode 5 includes a black electrode 5a and a white electrode 5b laminated on the black electrode 5a. Furthermore, a dielectric layer 8 that covers the display electrode 6 and the light shielding layer 7 is provided on the front glass substrate 3. The dielectric layer 8 will be described in detail later. Further, a protective layer 9 made of magnesium oxide (MgO) or the like is formed on the surface of the dielectric layer 8.

On the rear glass substrate 11, a plurality of strip-like address electrodes 12 are arranged in parallel to each other in a direction orthogonal to the display electrodes 6. Further, a base dielectric layer 13 that covers the address electrodes 12 is formed. Further, on the base dielectric layer 13 formed between the address electrodes 12, barrier ribs 14 having a predetermined height are formed to divide the discharge space 16. Between the barrier ribs 14, a phosphor layer 15 that emits red light by ultraviolet rays, a phosphor layer 15 that emits blue light, and a phosphor layer 15 that emits green light are sequentially formed.

A discharge cell is formed at a position where the display electrode 6 and the address electrode 12 intersect. A discharge cell having a phosphor layer 15 that emits red light, a discharge cell that has a phosphor layer 15 that emits blue light, and a discharge cell that has a phosphor layer 15 that emits green light form a pixel for color display. The

[2. Manufacturing method of PDP1]
[2-1. Manufacturing method of front plate 2]
As shown in FIG. 2, scan electrode 4, sustain electrode 5, and light shielding layer 7 are formed on front glass substrate 3. The display electrode 6 has a scan electrode 4 and a sustain electrode 5. Scan electrode 4 and sustain electrode 5 have

white electrodes

4b and 5b containing silver (Ag) for ensuring conductivity. Scan electrode 4 and sustain electrode 5 have

black electrodes

4a and 5a containing a black pigment in order to improve the contrast of the image display surface. The white electrode 4b is laminated on the black electrode 4a. The white electrode 5b is laminated on the black electrode 5a.

Specifically, a black paste containing a black pigment is applied to the front glass substrate 3 by a screen printing method or the like. Next, the applied black paste is exposed through a predetermined mask. Next, a white paste containing Ag is applied onto the black paste by a screen printing method or the like. Next, the white paste and the black paste are exposed through a predetermined mask. Then, a predetermined pattern is formed by developing the white paste and the black paste. Then, the

black electrodes

4a and 5a, the light shielding layer 7, and the

white electrodes

4b and 5b are formed by baking.

Next, a dielectric layer 8 that covers the display electrode 6 and the light shielding layer 7 is provided. A dielectric paste is used as the material of the dielectric layer 8. The dielectric paste is applied on the front glass substrate 3. Further, the applied dielectric paste is baked. The dielectric layer 8 will be described in detail later.

Next, a protective layer 9 made of magnesium oxide (MgO) or the like is formed on the dielectric layer 8 by a vacuum deposition method.

The front plate 2 having the scan electrode 4, the sustain electrode 5, the light shielding layer 7, the dielectric layer 8, and the protective layer 9 on the front glass substrate 3 is completed through the above steps.

[2-2. Manufacturing method of back plate 10]
As shown in FIG. 1, the address electrode 12, the base dielectric layer 13, the barrier ribs 14, and the phosphor layer 15 are formed on the rear glass substrate 11.

First, address electrodes 12 are formed on the rear glass substrate 11. Specifically, a paste containing silver (Ag) is applied onto the rear glass substrate 11 by a screen printing method. Next, the address electrode paste is patterned by photolithography. Next, the address electrode 12 is formed by baking the patterned address electrode paste. Here, besides the method of screen printing the address electrode paste, a method of forming a metal film on the rear glass substrate 11 by a sputtering method, a vapor deposition method, or the like can be used.

Next, a base dielectric paste is applied on the rear glass substrate 11 on which the address electrodes 12 are formed so as to cover the address electrodes 12 by a die coating method or the like. Thereafter, the base dielectric layer 13 is formed by firing the base dielectric paste. The base dielectric paste is a paint containing a base dielectric material such as glass powder, a binder, and a solvent.

Next, barrier rib paste containing barrier rib material is applied on the underlying dielectric layer 13. The partition wall paste is patterned by photolithography. Next, the partition wall 14 is formed by baking the patterned partition wall paste. In addition to the photolithography method, a sand blast method or the like can be used.

Next, a phosphor paste containing a phosphor material is applied on the underlying dielectric layer 13 between the adjacent barrier ribs 14 and on the side surfaces of the barrier ribs 14. Next, the phosphor layer 15 is formed by firing the phosphor paste.

Through the above steps, the back plate 10 having the address electrodes 12, the base dielectric layer 13, the partition walls 14, and the phosphor layer 15 on the back glass substrate 11 is completed.

[2-3. Assembly method of front plate 2 and rear plate 10]
The front plate 2 and the back plate 10 are provided facing each other so that the display electrodes 6 and the address electrodes 12 are orthogonal to each other. Next, the periphery of the front plate 2 and the back plate 10 is sealed with glass frit. Next, a discharge gas containing Ne, Xe or the like is sealed in the discharge space 16 to complete the PDP 1.

[3. Details of Dielectric Layer 8]
In order to reduce the power consumption of the PDP, it is effective to reduce the amount of current at the start of discharge. When the capacity of the discharge cell is large, the amount of current flowing through the discharge cell in one light emission increases. Therefore, the power consumption of the PDP increases.

In order to reduce the capacity of the discharge cell, for example, the relative dielectric constant of the dielectric layer may be lowered. However, it has been difficult to lower the dielectric constant of a low-melting-point dielectric glass mainly composed of dibismuth trioxide (Bi ₂ O ₃ ) or zinc oxide (ZnO) that has been conventionally used.

On the other hand, dielectric glass mainly composed of silicon dioxide (SiO ₂ ) or diboron trioxide (B ₂ O ₃ ) has a relative dielectric constant of about 5 to 7. However, if the relative dielectric constant is made 5.5 or less, the melting point becomes high. As the melting point increases, it is required to increase the firing temperature. That is, sufficient heat treatment becomes difficult at the firing temperature of the firing step in a general PDP manufacturing method.

As an attempt to lower the dielectric constant of the dielectric layer, it is conceivable to mix a dielectric glass material and SiO ₂ filler particles (silica particles). The relative dielectric constant of the silica particles is about 4. Therefore, the relative dielectric constant can be reduced as compared with the conventional dielectric layer. However, simply mixing silica particles in the dielectric layer deteriorates the optical properties (particularly the haze value) of the dielectric layer. Furthermore, there is a problem that the dielectric strength of the dielectric layer is lowered. The haze value is an index indicating the degree of cloudiness of a substance. The smaller the haze value, the higher the transparency. The greater the haze value, the greater the degree of haze. The haze value is calculated by the ratio of transmitted light and scattered light.

The inventors examined the cause of the above-mentioned adverse effects. The cause was a gap formed at the interface between the agglomerated silica particles and the dielectric glass. That is, the silica particles are not uniformly dispersed in the dielectric paste during the production of the dielectric paste, and the silica particles aggregate during firing.

The dielectric layer is fired at around 600 ° C. At around 600 ° C., the dielectric glass material powder is very reactive. Therefore, the dielectric glass material shrinks while being bonded one after another. On the other hand, silica particles have low reactivity. Therefore, it is difficult to bond not only to the silica particles but also to the powder of the dielectric glass material. Therefore, it is considered that the voids between the powders of the dielectric glass material that already existed at the stage before firing expand after firing.

The optical characteristics deteriorate due to scattering of the transmitted light in the gaps described above. In addition, the withstand voltage decreases due to the presence of the air gap.

In contrast, in the present embodiment, as an example, the dielectric layer 8 includes silica particles 20 and a dielectric glass layer 21 that is a glass layer. The dielectric constant of the dielectric layer 8 is 5.5 or less. The particle size of the silica particles 20 is preferably 100 nm or more and 1000 nm or less.

Note that an LCR meter was used to measure the relative permittivity. The relative dielectric constant is a value when the frequency is 1 kHz.

By setting the particle size of the silica particles 20 to 100 nm or more, the silica particles 20 are uniformly dispersed in the dielectric paste during the production of the dielectric paste. Therefore, voids are unlikely to occur at the interface between the dielectric glass layer 21 and the silica particles 20 during firing. Therefore, deterioration of the optical characteristics is suppressed. In addition, a decrease in withstand voltage is suppressed.

In addition, by setting the particle size of the silica particles 20 to 1000 nm or less, the refractive index difference between the silica particles 20 and the dielectric glass layer 21 can be minimized. Therefore, deterioration of the haze value due to the refractive index difference is suppressed.

The particle size of the silica particles 20 is more preferably 400 nm or more and 700 nm or less. This is because the deterioration of the optical characteristics, the lowering of the withstand voltage, and the haze value are further suppressed.

Note that, as a modification of the present embodiment, another means for suppressing the above-described generation of voids is shown. Specifically, an additive having a composition different from that of the silica particles 20 is added to the dielectric glass layer 21.

As described above, silica particles have low reactivity during firing. That is, it is considered that the activity of the surface of the silica particles is low, so that it is not compatible with other glass materials. Therefore, by adding an additive having a composition different from that of the silica particles around the silica particles, a part of the tetrahedral structure of the silica particles is destroyed. Therefore, the activity of the surface of the silica particles is increased. Therefore, generation | occurrence | production of a space | gap can be suppressed.

For this reason, in the modification, the dielectric glass layer 21 is made of B ₂ O ₃ , ZnO, MgO, CaO, potassium oxide (K ₂ O), lithium oxide (Li ₂ O), and sodium oxide (Na ₂ O). At least one selected from the above is added. The addition amount is preferably 0.1 mol% or more and less than 20 mol% with respect to the dielectric glass layer 21. If it is less than 0.1 mol%, the effect is extremely small. On the other hand, at 20 mol% or more, other adverse effects such as coloring of the dielectric layer occur.

As shown in FIG. 2, the dielectric layer 8 according to the present embodiment includes silica particles 20 and a dielectric glass layer 21 that is a glass layer. Silica particles 20 are dispersed in the dielectric layer 8. For convenience of explanation, the size and number of silica particles 20 shown in FIG. 2 are different from the actual product.

Conventionally, in order to enable firing at about 450 ° C. to about 600 ° C., the dielectric glass contains 20% by weight or more of lead oxide. However, in this embodiment, the dielectric glass does not contain lead oxide for environmental consideration. That is, the dielectric layer 8 does not contain lead oxide.

[3-1. Production of dielectric paste]
The dielectric paste includes a dielectric glass slurry in which dielectric glass particles are dispersed, a silica particle slurry in which silica particles 20 are dispersed, and a vehicle.

[3-1-1. Dielectric glass slurry]
As an example, the main component of the dielectric glass fine particles is Bi ₂ O ₃ . At least one or more of the group consisting of B ₂ O ₃ , ZnO, MgO, CaO, K ₂ O, Li ₂ O and Na ₂ O may be added to the dielectric glass fine particles. The addition amount is 0.1 mol% or more and 20 mol% or less with respect to the dielectric glass layer 21.

First, a dielectric glass material composed of the exemplified composition components is pulverized by a wet jet mill or a ball mill so as to have an average particle diameter of 0.5 μm to 3.0 μm to produce dielectric glass fine particles. The softening point of the dielectric glass fine particles is 600 ° C. or less.

The dielectric glass slurry contains 10% to 65% by weight of dielectric glass particles and 35% to 90% by weight of solvent. As the solvent, for example, an alcohol type, a glycol type, or an aqueous type is used.

A lubricant or a dispersant may be added to the dielectric glass slurry. The dielectric glass slurry having such a configuration improves dispersibility.

[3-1-2. Silica particle slurry]
In the silica particle slurry, 1 to 20% by weight of silica particles 20 are dispersed in a solvent of 80 to 99% by weight. The main component of the silica particles 20 is SiO ₂ . However, in addition to silica particles, aluminum oxide (Al ₂ O ₃ ), ZnO, gallium oxide (Ga ₂ O ₃ ), or a composite oxide thereof can also be used. The softening point of the silica particles 20 is 700 ° C. or higher. As the solvent, for example, an alcohol type, a glycol type, or an aqueous type is used.

The particle size of the silica particles is preferably 100 nm or more and 1000 nm or less. More preferably, it is 400 nm or more and 700 nm or less. In addition, a particle size means a volume accumulation average diameter (D50). For the measurement of the particle size, a laser diffraction particle size distribution analyzer MT-3300 (manufactured by Nikkiso Co., Ltd.) was used. A lubricant or a dispersant may be added to the silica particle slurry. Dispersibility of the silica particle slurry having such a configuration is improved.

[3-1-3. Dielectric paste]
The dielectric glass slurry and the silica particle slurry are produced separately. The dielectric paste according to the present embodiment is obtained by mixing and dispersing a dielectric glass slurry and a silica particle slurry. Before applying the dielectric paste to the front glass substrate 3, the dielectric glass slurry and the silica particle slurry are mixed and dispersed. Furthermore, a binder component such as a vehicle is mixed and dispersed as necessary.

The binder component is terpineol or butyl carbitol acetate containing 1% to 20% by weight of ethyl cellulose or acrylic resin. In addition, dioctyl phthalate, dibutyl phthalate, triphenyl phosphate, and tributyl phosphate may be added to the dielectric paste as a plasticizer. Printability may be improved by adding glycerol monooleate, sorbitan sesquioleate, homogenol (product name of Kao Corporation), phosphate ester of alkylallyl group or the like as a dispersant. In addition, you may match | combine a binder component with the solvent used at the time of glass particle grinding | pulverization. The timing of mixing and dispersing the binder component is not limited to when the dielectric glass slurry and the silica particle slurry are mixed and dispersed. That is, the dielectric glass slurry or the silica particle slurry may be produced at the time.

According to the method of manufacturing a dielectric paste according to the present embodiment, the dielectric glass fine particles and the silica particles 20 are more uniformly dispersed in the dielectric paste.

The content of the silica particles 20 in the dielectric layer 8 is preferably 5% by volume or more and 30% by volume or less. When the content of the silica particles 20 is less than 5% by volume, it is difficult to reduce the relative dielectric constant of the dielectric layer 8. On the other hand, when the content of the silica particles 20 exceeds 30% by volume, the haze value of the dielectric layer 8 is deteriorated. Further, in the present embodiment, the content and particle size of the silica particles 20 are appropriately defined within the above ranges so that the dielectric constant of the dielectric layer 8 is 5.5 or less. Thereby, the reduction effect of the power consumption of PDP1 is acquired.

In order to keep the content of the silica particles 20 in the dielectric layer 8 within a predetermined range, it is preferable to keep the content of the silica particles 20 in the dielectric paste within a predetermined range. That is, the dielectric glass slurry and the silica particle slurry may be mixed and dispersed according to the specified ratio. Alternatively, the content of the silica particles 20 in the silica particle slurry may fall within a predetermined range at the production stage of the silica particle slurry.

[3-2. Regarding Thermal Expansion Coefficient of Dielectric Layer 8]
On the other hand, the inventors' investigations have revealed that in a PDP having a dielectric layer containing silica particles, the front glass substrate is greatly warped after the dielectric layer is baked. It is not easy to assemble a front plate and a back plate having a front glass substrate that is greatly warped. Even if assembled, the image quality of the PDP deteriorates. In addition, the impact strength of the PDP is greatly reduced.

Generally, a dielectric glass material having a thermal expansion coefficient close to that of the front glass substrate is selected so that the front glass substrate does not greatly warp after firing. Furthermore, in recent years, in order to reduce the weight of the PDP, a front glass substrate having a thickness of 2 mm or less is often selected. When the thickness of the front glass substrate is reduced, the impact strength of the PDP is significantly reduced. For this reason, a dielectric glass material having a thermal expansion coefficient smaller than that of the front glass substrate is selected. That is, the impact strength is increased by making the dielectric layer have a compressive stress.

When a low relative dielectric constant material such as silica particles is not mixed, a dielectric glass material having a thermal expansion coefficient smaller than that of the substrate may be appropriately selected as described above. That is, there is no big problem about ensuring sufficient impact strength. For example, when the dielectric layer is formed only from a low melting point dielectric glass material, an appropriate compressive stress is generated in the dielectric layer by adjusting the thermal expansion coefficient to about 75 × 10 ⁻⁷ / ° C. This is because the coefficient of thermal expansion of a general front glass substrate is smaller than 83 × 10 ⁻⁷ / ° C. Therefore, sufficient impact strength can be ensured.

However, problems arise when mixing low dielectric constant materials such as silica particles. For example, the thermal expansion coefficient of silica particles is 24 × 10 ⁻⁷ / ° C. Therefore, a dielectric layer in which silica particles are added to a conventionally used dielectric glass layer has a low thermal expansion coefficient. For example, when the content of silica particles in the dielectric layer is 20% by volume and the content of the dielectric glass layer is 80% by volume, the thermal expansion coefficient of the entire dielectric layer is about 65 × 10 ⁻⁷ / ° C. Become. In this case, the thermal expansion coefficient of the entire dielectric layer is smaller than that of the front glass substrate. Therefore, compressive stress can be generated in the dielectric layer.

However, there is a large difference in the thermal expansion coefficient between the front glass substrate and the dielectric layer. Therefore, the front glass substrate after firing the dielectric layer is greatly warped. When the thermal expansion coefficient of the entire dielectric layer is 65 × 10 ⁻⁷ / ° C., warpage of about 2.0 mm occurs on the front glass substrate in the 42-inch diagonal PDP. When warpage of about 2.0 mm occurs on the front glass substrate, it becomes difficult to bond the front plate and the back plate with high accuracy. As a result, the image quality of the PDP deteriorates. In order to maintain the image quality of the PDP, the warp of the front glass substrate is preferably 1 mm or less.

In contrast, dielectric layer 8 in the present embodiment includes silica particles 20 and dielectric glass layer 21. The dielectric constant of the dielectric layer 8 is 5.5 or less. The dielectric glass layer 21 has a thermal expansion coefficient of 79 × 10 ⁻⁷ / ° C. or higher and 95 × 10 ⁻⁷ / ° C. or lower. Content of the silica particle 20 is 5 volume% or more and 30 volume% or less.

With this configuration, the dielectric layer 8 has a compressive stress. Moreover, the curvature of the front glass substrate 3 will be 1 mm or less. Therefore, the impact strength of the PDP 1 can be improved. Further, image quality deterioration of the PDP 1 is suppressed. More preferably, the dielectric glass layer 21 has a thermal expansion coefficient of 79 × 10 ⁻⁷ / ° C. or more and 90 × 10 ⁻⁷ / ° C. or less, and the content of the silica particles 20 is 5 volume% or more and 20 volume. % Or less.

When the content of the silica particles 20 is 5% by volume, the thermal expansion coefficient of the dielectric glass layer 21 should be 79 × 10 ⁻⁷ / ° C. or more in order to set the warpage of the front glass substrate 3 to 1 mm or less. preferable. On the other hand, when the thermal expansion coefficient of the dielectric glass layer 21 exceeds 95 × 10 ⁻⁷ / ° C., the front glass substrate 3 warps in the reverse direction.

[3-2. Method for Forming Dielectric Layer 8]
As a method for forming the dielectric layer 8, a screen printing method, a die coating method, or the like is used. First, a dielectric paste is applied on the front glass substrate 3. The applied dielectric paste constitutes a dielectric paste film. The coating thickness of the dielectric paste film is appropriately set in consideration of the rate of shrinkage due to firing. Next, the dielectric paste film is dried in a temperature range of 100 ° C. to 200 ° C. Next, the dielectric paste film is baked. The firing temperature is preferably in the range of 450 ° C to 600 ° C. A more preferable firing temperature range is 550 ° C to 590 ° C. The dielectric layer 8 having the silica particles 20 and the dielectric glass layer 21 is formed by firing.

That is, the firing temperature is higher than the softening point of the dielectric glass fine particles and lower than the softening point of the silica particles 20. Therefore, the dielectric glass fine particles are softened by firing and bonded to the surrounding fine particles. Furthermore, the dielectric glass layer 21 is formed by hardening after baking. The softening point of the dielectric glass layer 21 is equal to the softening point of the dielectric glass fine particles. That is, the softening point of the dielectric glass layer 21 is 600 ° C. or lower which is lower than the firing temperature. The softening point of the dielectric glass particles is preferably 300 ° C. or higher. This is because if it is less than 300 ° C., it lacks stability. Therefore, the softening point of the dielectric glass layer 21 is preferably 300 ° C. or higher.

On the other hand, the silica particles 20 are not softened. That is, the initial shape of the silica particles 20 is maintained.

Further, as a method of forming the dielectric layer 8, the following method is also used. First, a sheet obtained by applying and drying a dielectric paste on a film is used. Next, the dielectric paste formed on the sheet is transferred to the front glass substrate 3. Next, the dielectric layer 8 composed of the silica particles 20 and the dielectric glass layer 21 is formed by firing in a temperature range of 450 ° C. to 600 ° C., more preferably 550 ° C. to 590 ° C.

Note that the luminance of the PDP 1 is improved as the thickness of the dielectric layer 8 is reduced. Further, the discharge voltage of the PDP 1 decreases as the thickness of the dielectric layer 8 decreases. Therefore, it is preferable that the thickness of the dielectric layer 8 is as small as possible within a range where the withstand voltage does not decrease. In the present embodiment, as an example, the film thickness of the dielectric layer 8 is not less than 10 μm and not more than 30 μm from both the viewpoint of dielectric strength and the viewpoint of visible light transmittance.

[4. Example]
A PDP 1 according to the present embodiment was prototyped. It is suitable for 42-inch diagonal high-definition televisions. The height of the partition walls is 0.15 mm, the distance between the partition walls is 0.15 mm, and the distance between the display electrodes 6 is 0.06 mm. A Ne—Xe-based mixed gas having a Xe content of 10% by volume was sealed to a pressure of 60 kPa. The thickness of the glass substrate is 1.8 mm. The film thickness of the dielectric layer 8 is 30 μm.

Table 1 shows the characteristics of the dielectric glass layer 21. The dielectric glass layer 21 is a SiO ₂ —B ₂ O ₃ —R ₂ O system (R is Na, K). The silica particles 20 have a softening point of 820 ° C., a thermal expansion coefficient of 24 × 10 ⁻⁷ / ° C., and a relative dielectric constant of 4.1.

Samples 1 to 6 have a softening point of 650 ° C. or lower. Samples 1 to 3 have a thermal expansion coefficient of less than 79 × 10 ⁻⁷ / ° C. Samples 4 to 6 have a thermal expansion coefficient of 79 × 10 ⁻⁷ / ° C. or higher. For the PDP 1 having the dielectric glass layer 21 of Samples 1 to 6, the warpage of the front glass substrate 3 and the stress of the dielectric layer 8 were measured. Regarding the warp of the front glass substrate 3, a positive value is a warp in which the dielectric layer 8 side is convex. About the stress of the dielectric layer 8, what is shown by the negative value is a compressive stress.

The dielectric layer 8 composed only of the dielectric glass layers 21 of Samples 1 to 3 and not including the silica particles 20 had a stress of −0.5 MPa to −1.8 MPa. The amount of warpage of the front glass substrate 3 was 0.5 mm to 1.4 mm. The relative dielectric constant of the dielectric layer 8 was 5.7 to 6.0. Therefore, the power consumption reduction of the PDP 1 is not sufficient.

On the other hand, the dielectric layer 8 containing 5 to 30% by volume of silica particles 20 in the dielectric glass layers 21 of Samples 1 to 3 had a stress of −1.6 MPa to −4.8 MPa. The stress showed a good value. However, the amount of warpage of the front glass substrate 3 was 1.3 mm to 3.5 mm. Therefore, PDP1 did not satisfy the standards for non-defective products.

However, the dielectric layer 8 containing 5 to 30% by volume of silica particles 20 in the dielectric glass layers 21 of Samples 4 to 6 had a stress of −0.4 MPa to −3.3 MPa. The amount of warpage of the front glass substrate 3 was -0.9 mm to 1.0 mm. The relative dielectric constant of the dielectric layer 8 was 5.2 to 5.5. Therefore, PDP1 satisfied the standard for non-defective products. Moreover, the power consumption of PDP1 was able to be reduced.

Further, as shown in FIG. 3, when the particle size of the silica particles 20 is 100 nm or more and 1000 nm or less, the haze value is greatly reduced. Furthermore, when the particle size of the silica particles 20 is 400 nm or more and 700 nm or less, the haze value is stably low, which is more preferable. Moreover, the effect that a haze value falls by the content rate of the silica particle 20 in the dielectric material layer 8 being 20 volume% or less appears. The haze value of each sample is a relative value when the haze value in the dielectric layer 8 containing 50% by volume of the silica particles 20 having a particle size of 5000 nm is 1.

For the measurement of the haze value, a haze / transmittance meter “HM-150” (manufactured by Murakami Color Research Laboratory Co., Ltd.) was used. In the embodiment, the light transmittance (visible light transmittance) when light having a single wavelength of 550 nm is incident on the front glass substrate 3 on which the dielectric layer 8 is formed from a direction orthogonal to the front glass substrate 3. ) And haze values were measured.

In the present embodiment, the thermal expansion coefficient is an average value from 100 ° C. to 300 ° C. The thermal expansion coefficient is measured by, for example, a differential thermal dilatometer.

[5. Summary]
The PDP 1 according to the present embodiment includes a front plate 2 and a back plate 10 provided to face the front plate 2. The front plate 2 includes a display electrode 6 and a dielectric layer 8 that covers the display electrode 6. The dielectric layer 8 includes silica particles 20 and a dielectric glass layer 21. The thermal expansion coefficient of the dielectric glass layer 21 is 79 × 10 ⁻⁷ / ° C. or higher and 95 × 10 ⁻⁷ / ° C. or lower. Content of the silica particle 20 in the dielectric material layer 8 is 5 volume% or more and 30 volume% or less. The dielectric constant of the dielectric layer 8 is 5.5 or less.

The PDP 1 according to the present embodiment can suppress impact strength deterioration and image quality deterioration, and can realize low power consumption.

The thermal expansion coefficient of the dielectric glass layer 21 is 79 × 10 ⁻⁷ / ° C. or more and 90 × 10 ⁻⁷ / ° C. or less, and the content of the silica particles 20 in the dielectric layer 8 is 5% by volume or more and 20% or less. It is preferable that it is below volume%.

Further, the particle diameter of the silica particles 20 is preferably 100 nm or more and 1000 nm or less. This is because good optical characteristics can be obtained.

Furthermore, the particle size of the silica particles 20 is more preferably 400 nm or more and 700 nm or less. Further, good optical characteristics can be obtained.

As described above, the technology disclosed in the present embodiment realizes a low power consumption PDP and is useful for a large screen display device.

1 PDP
2 Front plate 3 Front glass substrate 4

Scan electrode

4a,

5a Black electrode

4b, 5b White electrode 5 Maintenance electrode 6 Display electrode 7 Black stripe (light shielding layer)
8 Dielectric layer 9 Protective layer 10 Back plate 11 Back glass substrate 12 Address electrode 13 Base dielectric layer 14 Partition 15 Phosphor layer 16 Discharge space 20 Silica particles 21 Dielectric glass layer

Claims

A front plate and a back plate provided to face the front plate;
The front plate has a display electrode and a dielectric layer covering the display electrode,
The dielectric layer includes silica particles and a glass layer,
The thermal expansion coefficient of the glass layer is 79 × 10 −7 / ° C. or more and 95 × 10 −7 / ° C. or less.
The content of the silica particles in the dielectric layer is 5 vol% or more and 30 vol% or less,
The dielectric constant of the dielectric layer is 5.5 or less.
Plasma display panel.
The thermal expansion coefficient of the glass layer is 79 × 10 −7 / ° C. or higher and 90 × 10 −7 / ° C. or lower.
The content of the silica particles in the dielectric layer is 5% by volume or more and 20% by volume or less.
The plasma display panel according to claim 1.
The silica particles have a particle size of 100 nm to 1000 nm.
The plasma display panel according to claim 1.
The silica particles have a particle size of 400 nm to 700 nm.
The plasma display panel according to claim 1.
The dielectric layer has a compressive stress;
The plasma display panel according to claim 1.