WO2013018335A1

WO2013018335A1 - Plasma display panel and manufacturing method thereof

Info

Publication number: WO2013018335A1
Application number: PCT/JP2012/004793
Authority: WO
Inventors: 貴仁中山; 幸弘森田; 上野　巌; 卓司辻田; 章伸岩本; 秀司河原崎
Original assignee: パナソニック株式会社
Priority date: 2011-08-02
Filing date: 2012-07-27
Publication date: 2013-02-07
Also published as: JP2013033627A

Abstract

This plasma display panel is provided with a front surface plate (2) and a back surface plate (10) arranged opposite of the front surface plate (2). The front surface plate (2) has a dielectric layer (8) and a protective layer (9) covering said dielectric layer. The protective layer (9) contains a metal oxide layer comprising one or more types selected from a group consisting of magnesium oxide, calcium oxide, strontium oxide and barium oxide. The ratio of the secondary electron emission coefficient in the Ne gas of the protective layer to the secondary electron emission coefficient in the Kr gas of the protective layer is 0.02-0.12.

Description

Plasma display panel and manufacturing method thereof

The technology of the present disclosure relates to a plasma display panel used for a display device or the like and a manufacturing method thereof.

A plasma display panel (hereinafter referred to as PDP) which is one of display devices has a protective layer. In order to increase the number of initial electron emissions from the protective layer, for example, attempts have been made to add silicon (Si) or aluminum (Al) to MgO of the protective layer (for example, see Patent Document 1).

JP 2002-260535 A

The PDP according to the present disclosure includes a front plate and a back plate disposed to face the front plate. The front plate has a dielectric layer and a protective layer covering the dielectric layer. The protective layer includes one or more metal oxide layers selected from the group consisting of magnesium oxide, calcium oxide, strontium oxide, and barium oxide. The ratio of the secondary electron emission coefficient in the Ne gas of the protective layer to the secondary electron emission coefficient in the Kr gas of the protective layer is 0.02 or more and 0.12 or less.

The manufacturing method of the present disclosure is a manufacturing method of a PDP having a discharge space provided between a front plate and a back plate. The front plate has a dielectric layer and a protective layer covering the dielectric layer. The protective layer includes one or more metal oxide layers selected from the group consisting of magnesium oxide, calcium oxide, strontium oxide, and barium oxide. The ratio of the secondary electron emission coefficient in the Ne gas of the protective layer to the secondary electron emission coefficient in the Kr gas of the protective layer is 0.02 or more and 0.12 or less. In the manufacturing method, the protective layer is exposed to the reducing organic gas by introducing a gas containing the reducing organic gas into the discharge space, and then the reducing organic gas is discharged from the discharge space. Enclosing the gas in the discharge space.

FIG. 1 is a perspective view showing the structure of a PDP. FIG. 2 is a cross-sectional view showing the configuration of the front plate. FIG. 3 is a diagram illustrating a manufacturing flow of the PDP according to the embodiment. FIG. 4 is a diagram illustrating a first temperature profile example. FIG. 5 is a diagram illustrating a second temperature profile example. FIG. 6 is a diagram illustrating a third temperature profile example. FIG. 7 is a diagram illustrating a result of X-ray diffraction analysis of the surface of the underlayer according to the embodiment. FIG. 8 is a diagram illustrating a result of X-ray diffraction analysis of another underlayer surface according to the embodiment. FIG. 9 is an enlarged view of the aggregated particles according to the embodiment. FIG. 10 is a diagram illustrating the relationship between the gas pressure in the PDP and the Vf according to the embodiment.

The embodiment will be described in detail below. The drawings are referred to as appropriate for the description of the embodiments. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and overlapping descriptions of substantially the same configuration may be omitted. This is for avoiding redundant description and facilitating understanding by those skilled in the art.

In addition, the inventors provide the accompanying drawings and the following description for those skilled in the art to fully understand the present disclosure. The inventors do not intend the subject matter recited in the claims to be limited by the present disclosure.

[1. Structure of PDP1]
The basic structure of the PDP 1 is a general AC surface discharge type PDP. As shown in FIG. 1 and FIG. 2, the PDP 1 includes a front plate 2 made of a front glass substrate 3 and a back plate 10 made of a back glass substrate 11 and the like. The front plate 2 and the back plate 10 are hermetically sealed with a sealing material whose outer peripheral portion is made of glass frit or the like. The discharge space 16 inside the sealed PDP 1 is filled with discharge gas such as neon (Ne) and xenon (Xe) at a pressure of 53 kPa (400 Torr) to 80 kPa (600 Torr).

On the front glass substrate 3, a pair of strip-shaped display electrodes 6 each consisting of a scanning electrode 4 and a sustain electrode 5 and a plurality of black stripes 7 are arranged in parallel to each other. A dielectric layer 8 that functions as a capacitor is formed on the front glass substrate 3 so as to cover the display electrodes 6 and the black stripes 7. Further, a protective layer 9 made of magnesium oxide (MgO) or the like is formed on the surface of the dielectric layer 8. The protective layer 9 will be described later in detail.

Scan electrode 4 and sustain electrode 5 are made of Ag on

transparent electrodes

4a and 5a made of conductive metal oxide such as indium tin oxide (ITO), tin oxide (SnO ₂ ), and zinc oxide (ZnO), respectively.

Electrodes

4b and 5b are stacked.

On the rear glass substrate 11, a plurality of data electrodes 12 made of a conductive material mainly composed of silver (Ag) are arranged in parallel to each other in a direction orthogonal to the display electrodes 6. The data electrode 12 is covered with a base dielectric layer 13. Further, a partition wall 14 having a predetermined height is formed on the underlying dielectric layer 13 between the data electrodes 12 to divide the discharge space 16. In the grooves between the barrier ribs 14, a phosphor layer 15 that emits red light by ultraviolet rays, a phosphor layer 15 that emits green light, and a phosphor layer 15 that emits blue light are sequentially applied and formed for each data electrode 12. Yes. A discharge cell is formed at a position where the display electrode 6 and the data electrode 12 intersect. Discharge cells having red, green, and blue phosphor layers 15 arranged in the direction of the display electrode 6 serve as pixels for color display.

[2. Manufacturing method of PDP1]
As shown in FIG. 3, the manufacturing method of the PDP 1 according to the present embodiment includes a front plate manufacturing step A1, a back plate manufacturing step B1, a frit coating step B2, a sealing step C1, a reducing gas introduction step C2, and an exhaust. It has process C3 and discharge gas supply process C4.

[2-1. Front plate manufacturing process A1]
In front plate manufacturing step A1, scan electrodes 4, sustain electrodes 5, and black stripes 7 are formed on front glass substrate 3 by photolithography. Scan electrode 4 and sustain electrode 5 have

metal bus electrodes

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

transparent electrodes

4a and 5a. The metal bus electrode 4b is laminated on the transparent electrode 4a. The metal bus electrode 5b is laminated on the transparent electrode 5a.

For the material of the

transparent electrodes

4a and 5a, indium tin oxide (ITO) or the like is used to ensure transparency and electric conductivity. First, an ITO thin film is formed on the front glass substrate 3 by sputtering or the like. Next,

transparent electrodes

4a and 5a having a predetermined pattern are formed by lithography.

As the material of the

metal bus electrodes

4b and 5b, an electrode paste containing silver (Ag), a glass frit for binding silver, a photosensitive resin, a solvent, and the like is used. First, an electrode paste is applied on the front glass substrate 3 by a screen printing method or the like. Next, the solvent in the electrode paste is removed by a drying furnace. Next, the electrode paste is exposed through a photomask having a predetermined pattern.

Next, the electrode paste is developed to form a metal bus electrode pattern. Finally, the metal bus electrode pattern is fired at a predetermined temperature in a firing furnace. That is, the photosensitive resin in the metal bus electrode pattern is removed. Further, the glass frit in the metal bus electrode pattern is melted. The molten glass frit is vitrified again after firing.

Metal bus electrodes

4b and 5b are formed by the above steps. The black stripe 7 is formed of a material containing a black pigment.

Next, the dielectric layer 8 is formed. As a material for the dielectric layer 8, a dielectric paste containing a dielectric glass frit, a resin, a solvent, and the like is used. First, a dielectric paste is applied on the front glass substrate 3 so as to cover the display electrode 6 with a predetermined thickness by a die coating method or the like. Next, the solvent in the dielectric paste is removed by a drying furnace. Finally, the dielectric paste is fired at a predetermined temperature in a firing furnace. That is, the resin in the dielectric paste is removed. In addition, the dielectric glass frit melts and resolidifies. Through the above steps, the dielectric layer 8 is formed. Here, besides the method of die coating the dielectric paste, a screen printing method, a spin coating method, or the like can be used.

Then, the protective layer 9 is formed. Details of the protective layer 9 will be described later.

Through the above steps, the front plate 2 having predetermined constituent members on the front glass substrate 3 is completed.

[2-2. Back plate manufacturing process B1]
Data electrodes 12 are formed on the rear glass substrate 11 by photolithography. As a material of the data electrode 12, a data electrode paste containing silver (Ag) for ensuring conductivity, a glass frit for binding silver, a photosensitive resin, a solvent, and the like is used. First, the data electrode paste is applied on the rear glass substrate 11 with a predetermined thickness by a screen printing method or the like. Next, the solvent in the data electrode paste is removed by a drying furnace. Next, the data electrode paste is exposed through a photomask having a predetermined pattern. Next, the data electrode paste is developed to form a data electrode pattern. Finally, the data electrode pattern is fired at a predetermined temperature in a firing furnace. That is, the photosensitive resin in the data electrode pattern is removed. Further, the glass frit in the data electrode pattern is melted. The molten glass frit is vitrified again after firing. The data electrode 12 is formed by the above process. Here, besides the method of screen printing the data electrode paste, a sputtering method, a vapor deposition method, or the like can be used.

Next, the base dielectric layer 13 is formed. As a material for the base dielectric layer 13, a base dielectric paste containing a dielectric glass frit, a resin, a solvent, and the like is used. First, a base dielectric paste is applied by a screen printing method or the like so as to cover the data electrode 12 on the rear glass substrate 11 on which the data electrode 12 is formed with a predetermined thickness. Next, the solvent in the base dielectric paste is removed by a drying furnace. Finally, the base dielectric paste is fired at a predetermined temperature in a firing furnace. That is, the resin in the base dielectric paste is removed. Further, the dielectric glass frit is melted. The molten dielectric glass frit is vitrified again after firing. Through the above steps, the base dielectric layer 13 is formed. Here, other than the method of screen printing the base dielectric paste, a die coating method, a spin coating method, or the like can be used. In addition, a film to be the base dielectric layer 13 can be formed by CVD (Chemical Vapor Deposition) method or the like without using the base dielectric paste.

Next, the barrier ribs 14 are formed by photolithography. As a material for the partition wall 14, a partition paste containing a filler, a glass frit for binding the filler, a photosensitive resin, a solvent, and the like is used. First, the barrier rib paste is applied on the underlying dielectric layer 13 with a predetermined thickness by a die coating method or the like. Next, the solvent in the partition wall paste is removed by a drying furnace. Next, the barrier rib paste is exposed through a photomask having a predetermined pattern. Next, the barrier rib paste is developed to form a barrier rib pattern. Finally, the partition pattern is fired at a predetermined temperature in a firing furnace. That is, the photosensitive resin in the partition pattern is removed. Further, the glass frit in the partition wall pattern is melted. The molten glass frit is vitrified again after firing. The partition wall 14 is formed by the above process. Here, in addition to the photolithography method, a sandblast method or the like can be used.

Next, the phosphor layer 15 is formed. As the material of the phosphor layer 15, a phosphor paste containing phosphor particles, a binder, a solvent, and the like is used. First, a phosphor paste is applied on the base dielectric layer 13 between adjacent barrier ribs 14 and on the side surfaces of the barrier ribs 14 by a dispensing method or the like. Next, the solvent in the phosphor paste is removed by a drying furnace. Finally, the phosphor paste is fired at a predetermined temperature in a firing furnace. That is, the resin in the phosphor paste is removed. The phosphor layer 15 is formed by the above steps. Here, in addition to the dispensing method, a screen printing method or the like can be used.

Through the above steps, the back plate 10 having predetermined constituent members on the back glass substrate 11 is completed.

[2-3. Frit application process B2]
A glass frit which is a sealing member is applied outside the image display area of the back plate 10 manufactured by the back plate manufacturing step B1. Thereafter, the glass frit is temporarily fired at a temperature of about 350 ° C. A solvent component etc. are removed by temporary baking.

As the sealing member, a frit containing bismuth oxide or vanadium oxide as a main component is desirable. Examples of the frit mainly composed of bismuth oxide include a Bi ₂ O ₃ —B ₂ O ₃ —RO—MO system (where R is any one of Ba, Sr, Ca, and Mg, and M is Any of Cu, Sb, and Fe)) and a filler made of an oxide such as Al ₂ O ₃ , SiO ₂ , and cordierite can be used. Further, as a frit containing vanadium oxide as a main component, for example, a filler made of an oxide such as Al ₂ O ₃ , SiO ₂ or cordierite is added to a V ₂ O ₅ —BaO—TeO—WO glass material. Things can be used.

The sealing process C1, the reducing gas introduction process C2, the exhaust process C3, and the discharge gas supply process C4 according to the present embodiment perform the processing of the temperature profile illustrated in FIGS. 4 to 6 in the same apparatus. .

The sealing temperature in FIGS. 4 to 6 is a temperature at which the front plate 2 and the back plate 10 are sealed by a frit that is a sealing member. The sealing temperature in the present embodiment is about 490 ° C., for example. The softening point in FIGS. 4 to 6 is the temperature at which the frit as the sealing member softens. The softening point in the present embodiment is about 430 ° C., for example. Furthermore, the exhaust temperature in FIGS. 4 to 6 is a temperature at which a gas containing a reducing organic gas is exhausted from the discharge space. The exhaust temperature in the present embodiment is about 400 ° C., for example.

[2-4. From sealing process C1 to discharge gas supply process C4]
The front plate 2 and the back plate 10 that has undergone the frit coating step B2 are arranged to face each other, and the peripheral portion is sealed by a sealing member. Thereafter, a discharge gas is sealed in the discharge space 16.

[2-4-1. First temperature profile]
As shown in FIG. 4, first, in the sealing step C1, the temperature rises from room temperature to the sealing temperature. The temperature is then maintained at the sealing temperature for the period ab. Thereafter, the temperature falls from the sealing temperature to the exhaust temperature during the period bc. In the period bc, the discharge space is exhausted. That is, the discharge space is in a reduced pressure state.

Next, in the reducing gas introduction step C2, the temperature is maintained at the exhaust temperature for the period cd. A gas containing a reducing organic gas is introduced into the discharge space during the period cd. During the period cd, the protective layer 9 is exposed to a gas containing a reducing organic gas.

Thereafter, in the exhaust process C3, the temperature is maintained at the exhaust temperature for a predetermined period. Thereafter, the temperature drops to about room temperature. During the period d-e, the discharge space is exhausted, so that a gas containing a reducing organic gas is exhausted.

Next, in the discharge gas supply step C4, a discharge gas is introduced into the discharge space. That is, the discharge gas is introduced in a period after e when the temperature drops to about room temperature.

[2-4-2. Second temperature profile]
As shown in FIG. 5, first, in the sealing step C1, the temperature rises from room temperature to the sealing temperature. The temperature is then maintained at the sealing temperature for the period ab. Thereafter, the temperature falls from the sealing temperature to the exhaust temperature during the period bc. The discharge space is exhausted during the period cd1 during which the temperature is maintained at the exhaust temperature. That is, the discharge space is in a reduced pressure state.

Next, in the reducing gas introduction step C2, the temperature is maintained at the exhaust temperature for the period d1-d2. A gas containing a reducing organic gas is introduced into the discharge space during the period d1-d2. The protective layer 9 is exposed to a gas containing a reducing organic gas during the period d1-d2.

Thereafter, in the exhaust process C3, the temperature is maintained at the exhaust temperature for a predetermined period. Thereafter, the temperature drops to about room temperature. During the period d2-e, the discharge space is exhausted, so that a gas containing a reducing organic gas is exhausted.

[2-4-3. Third temperature profile]
As shown in FIG. 6, first, in the sealing step C1, the temperature rises from room temperature to the sealing temperature. Next, the temperature is maintained at the sealing temperature for ab1-b2. The discharge space is exhausted during the period ab1. That is, the discharge space is in a reduced pressure state. Thereafter, the temperature falls from the sealing temperature to the exhaust temperature during the period b2-c.

The reducing gas introduction step C2 is performed within the period of the sealing step C1. The temperature is maintained at the sealing temperature for the period b1-b2. Thereafter, during the period b2-c, the temperature falls to the exhaust temperature. A gas containing a reducing organic gas is introduced into the discharge space during the period of b1-b2. During the period b1-b2, the protective layer 9 is exposed to a gas containing a reducing organic gas.

Thereafter, in the exhaust process C3, the temperature is maintained at the exhaust temperature for a predetermined period. Thereafter, the temperature drops to about room temperature. During the period ce, the gas including the reducing organic gas is discharged by exhausting the discharge space.

In addition, it has almost the same action in any temperature profile.

[2-4-4. Details of reducing organic gas]
As shown in Table 1, the reducing organic gas is preferably a CH-based organic gas having a molecular weight of 58 or less and a large reducing power. When at least one selected from various reducing organic gases is mixed with a rare gas or nitrogen gas, a gas containing the reducing organic gas is produced.

In Table 1, column C means the number of carbon atoms contained in one molecule of organic gas. The column of H means the number of hydrogen atoms contained in one molecule of the organic gas.

In the vapor pressure column, “A” is attached to a gas having a vapor pressure of 100 kPa or higher at 0 ° C. Furthermore, “C” is given to the gas whose vapor pressure at 0 ° C. is smaller than 100 kPa. In the boiling point column, a gas having a boiling point of 0 ° C. or less at 1 atm is marked with “A”. Furthermore, “C” is attached to a gas having a boiling point of greater than 0 ° C. at 1 atmosphere. In the column for easy decomposition, “A” is given to the gas that is easily decomposed. “B” is attached to a gas that is easily decomposed. In the column of reducing power, “A” is given to the gas having sufficient reducing power.

In Table 1, “A” means good characteristics. “B” means normal characteristics. “C” means insufficient properties.

From the viewpoint of easy handling of organic gas in the PDP manufacturing process, a reducing organic gas that can be supplied in a gas cylinder is desirable. Also, considering the ease of handling in the manufacturing process of PDP, a reducing organic gas having a vapor pressure at 0 ° C. of 100 kPa or higher, a reducing organic gas having a boiling point of 0 ° C. or lower, or a reducing organic gas having a low molecular weight is desirable.

Furthermore, part of the gas containing the reducing organic gas may remain in the discharge space even after the exhaust process C3. Therefore, it is desirable that the reducing organic gas has a characteristic that it is easily decomposed.

Reducing organic gas is a carbon that does not contain oxygen selected from acetylene, ethylene, methylacetylene, propadiene, propylene and cyclopropane, taking into consideration the ease of handling in the manufacturing process and the property of being easily decomposed. Hydrogen gas is desirable. At least one selected from these reducing organic gases may be mixed with a rare gas or nitrogen gas.

The lower limit of the mixing ratio of the rare gas or nitrogen gas and the reducing organic gas is determined according to the combustion ratio of the reducing organic gas used. The upper limit is about several volume%. If the mixing ratio of the reducing organic gas is too high, the organic component is likely to be polymerized to become a polymer. In this case, the polymer remains in the discharge space and affects the characteristics of the PDP. Therefore, it is preferable to appropriately adjust the mixing ratio according to the component of the reducing organic gas to be used.

The inventors conducted the same examination using hydrogen gas as another example of the reducing gas, but did not obtain the same effect as the reducing organic gas.

In addition, MgO, CaO, SrO, BaO, etc. have high reactivity with impurity gas, such as water and a carbon dioxide. In particular, by reacting with water and carbon dioxide, the discharge characteristics are likely to deteriorate, and the discharge characteristics of each discharge cell are likely to vary.

Therefore, in the sealing step C1, it is preferable to flow an inert gas so that the inside of the discharge space 16 is in a positive pressure state through a through hole opened in the discharge space 16, and then perform sealing. This is because the reaction between the protective layer 9 and the impurity gas can be suppressed. Nitrogen, helium, neon, argon, xenon, etc. can be used as the inert gas.

Also, dry air may be flowed instead of the inert gas. This is because at least the reaction with water can be suppressed and the production cost can be reduced compared with the inert gas.

Specifically, in the sealing step C1 shown in FIGS. 4 to 6, for example, nitrogen gas may be flowed at a flow rate of about 2 L / min during the period up to x when the temperature reaches the softening point. The discharge space 16 is maintained at a positive pressure by nitrogen gas. When the temperature exceeds the softening point, the supply of nitrogen gas is stopped. The discharge space 16 is kept at a positive pressure by nitrogen gas. The temperature is maintained at the sealing temperature for the period ab (ab2). The discharge space 16 is filled with nitrogen gas. Thereafter, the temperature falls from the sealing temperature to the exhaust temperature during the period bc (b2-c). During the period bc (b2-c), the nitrogen gas that has filled the discharge space 16 is exhausted. That is, the discharge space is in a reduced pressure state. The description for the subsequent period is the same as the above description.

[3. Details of Protective Layer 9]
The protective layer 9 is required to have a function of holding electric charge for generating discharge and a function of emitting secondary electrons during sustain discharge. The applied voltage is reduced by improving the charge retention performance. As the number of secondary electron emission increases, the sustain discharge voltage is reduced.

[3-1. Underlayer 91]
The protective layer 9 according to the present embodiment includes a base layer 91 and aggregated particles 92. The underlayer 91 includes at least a first metal oxide and a second metal oxide. The first metal oxide is MgO, and the second metal oxide is one selected from the group consisting of CaO, SrO and BaO. Furthermore, the underlayer 91 has at least one peak in the X-ray diffraction analysis. This peak is between the first peak in the X-ray diffraction analysis of the first metal oxide and the second peak in the X-ray diffraction analysis of the second metal oxide. The first peak and the second peak have the same plane orientation as the plane orientation indicated by the peak of the underlayer 91.

As shown in FIG. 7, the (111) plane orientation of CaO alone is indicated by a peak at a diffraction angle of 32.2 degrees. The (111) plane orientation of MgO alone is indicated by a peak with a diffraction angle of 36.9 degrees. The (111) plane orientation of SrO alone is indicated by a peak with a diffraction angle of 30.0 degrees. The (111) plane orientation of BaO alone is indicated by a peak with a diffraction angle of 27.9 degrees.

The foundation layer 91 according to the present embodiment includes MgO and at least two or more metal oxides selected from the group consisting of CaO, SrO, and BaO.

As shown in FIG. 7, the point A is a peak in the (111) plane orientation of the base layer 91 formed of two of MgO and CaO. Point B is a peak in the (111) plane orientation of the underlying layer 91 formed of two of MgO and SrO. Point C is a peak in the (111) plane orientation of the underlying layer 91 formed of two of MgO and BaO.

As shown in FIG. 7, the diffraction angle at point A is 36.1 degrees. Point A exists between the peak of the (111) plane orientation in the MgO simple substance that is the first metal oxide and the peak of the (111) plane orientation in the CaO simple substance that is the second metal oxide.

The diffraction angle at point B is 35.7 degrees. Point B exists between the peak of the (111) plane orientation in the MgO simple substance that is the first metal oxide and the peak of the (111) plane orientation in the SrO simple substance that is the second metal oxide.

The diffraction angle at point C is 35.4 degrees. The point C exists between the peak of the (111) plane orientation in the MgO simple substance that is the first metal oxide and the peak of the (111) plane orientation in the BaO simple substance that is the second metal oxide.

As shown in FIG. 8, the point D is a peak in the (111) plane orientation of the base layer 91 formed of three of MgO, CaO, and SrO. Point E is a peak in the (111) plane orientation of the base layer 91 formed of three of MgO, CaO, and BaO. The point F is a peak in the (111) plane orientation of the base layer 91 formed of three of BaO, CaO, and SrO.

That is, the point D corresponds to the diffraction angle of 36.9 degrees of the (111) plane orientation of MgO alone, which is the maximum diffraction angle of a single oxide, and SrO which is the minimum diffraction angle in the (111) plane orientation as a specific orientation plane. A peak exists at a diffraction angle of 33.4 degrees, which is between the diffraction angle of 30.0 degrees of a single (111) plane orientation. Similarly, peaks at points E and F exist at 32.8 degrees and 30.2 degrees between the maximum diffraction angle and the minimum diffraction angle, respectively.

In the present embodiment, the plane orientation (111) is exemplified. However, the same applies to other plane orientations.

The depth from the vacuum level of CaO, SrO and BaO exists in a shallow region as compared with MgO. Therefore, when driving the PDP, when electrons existing in the energy levels of CaO, SrO, and BaO transition to the ground state of Xe ions, the number of electrons emitted by the Auger effect is less than the energy level of MgO. It is thought that it will increase compared to the case of transition.

In addition, as described above, the peak of the base layer 91 in the X-ray diffraction analysis is between the peak of the first metal oxide and the peak of the second metal oxide. That is, it is considered that the energy level of the base layer 91 exists between single metal oxides, and the number of electrons emitted by the Auger effect is larger than that in the case of transition from the energy level of MgO.

As a result, the base layer 91 according to the present embodiment can exhibit better secondary electron emission characteristics as compared with MgO alone. As a result, the sustain voltage can be reduced. In particular, the discharge voltage can be reduced when the Xe partial pressure as the discharge gas is increased in order to increase the luminance. That is, a low-voltage and high-luminance PDP 1 can be realized.

The underlayer 91 is formed by a thin film forming method such as a sputtering method or an EB vapor deposition method. In the present embodiment, the foundation layer 91 is formed by EB vapor deposition. A target vapor deposition source is disposed in the vacuum vapor deposition chamber. An electron beam is irradiated to the deposition source. The components of the evaporation source are evaporated by the energy of the electron beam. The evaporated component adheres on the carried substrate. The degree of vacuum in the vacuum deposition chamber, the atmospheric gas, the irradiation intensity of the electron beam, and the like are appropriately adjusted.

The foundation layer 91 in the present embodiment includes at least a first metal oxide and a second metal oxide. The first metal oxide is MgO, and the second metal oxide is one selected from the group consisting of CaO, SrO and BaO. The vapor deposition source is prepared with components having a desired concentration.

For example, when the base layer 91 made of MgO and CaO is formed, the following procedure is shown. MgO powder and CaO powder are mixed so that it may become a predetermined density | concentration. Next, the mixed powder of MgO powder and CaO powder is sintered. The mixed powder is processed into a pellet shape having a thickness of about 2 mm and a diameter of about 5 mm by sintering. A sintered body processed into a pellet shape is a deposition source. It forms into a film on a test piece by the vapor deposition source from which a composition differs. The composition (concentration) of each film is analyzed. In this way, the base layer 91 having a desired concentration is formed.

The same applies to the sputtering method. A base layer 91 is formed by a target having a desired concentration.

[3-2. Aggregated particles 92]
Aggregated particles 92 are formed by aggregating a plurality of MgO crystal particles 92a, which are metal oxides. The agglomerated particles 92 are preferably distributed uniformly over the entire surface of the base layer 91. This is because the variation of the discharge voltage in the PDP 1 is reduced.

The MgO crystal particles 92a can be manufactured by either a gas phase synthesis method or a precursor firing method. In the gas phase synthesis method, first, a metal magnesium material having a purity of 99.9% or more is heated in an atmosphere filled with an inert gas. Furthermore, metallic magnesium is directly oxidized by introducing a small amount of oxygen into the atmosphere. In this manner, MgO crystal particles 92a are produced.

In the precursor firing method, the MgO precursor is uniformly fired at a high temperature of 700 ° C. or higher. Next, by slowly cooling, MgO crystal particles 92a are produced. Examples of the precursor include magnesium alkoxide (Mg (OR) ₂ ), magnesium acetylacetone (Mg (acac) ₂ ), magnesium hydroxide (Mg (OH) ₂ ), magnesium carbonate (MgCO ₂ ), magnesium chloride (MgCl ₂ ). ), Magnesium sulfate (MgSO ₄ ), magnesium nitrate (Mg (NO ₃ ) ₂ ), or magnesium oxalate (MgC ₂ O ₄ ). Depending on the selected compound, it may usually take the form of a hydrate. Hydrate can also be used as a precursor. The compound as the precursor is adjusted so that the purity of magnesium oxide (MgO) obtained after firing is 99.95% or higher, desirably 99.98% or higher. If a certain amount of impurity elements such as various alkali metals, B, Si, Fe, and Al are mixed in the precursor compound, unnecessary interparticle adhesion and sintering occur during heat treatment. As a result, it becomes difficult to obtain highly crystalline MgO crystal particles. Therefore, it is preferable to prepare the precursor in advance, such as removing the impurity element from the compound.

[3-2-1. Details of Aggregated Particle 92]
The aggregated particles 92 are those in which crystal particles 92a having a predetermined primary particle size are aggregated or necked. In other words, it is not bonded as a solid with a large bonding force, but a plurality of primary particles form an aggregate body due to static electricity, van der Waals force, etc., and due to external stimuli such as ultrasound , Part or all of them are bonded to such a degree that they become primary particles. As shown in FIG. 9, the aggregated particles 92 have a particle size of about 1 μm, and the crystal particles 92a have a polyhedral shape having seven or more faces such as a tetrahedron and a dodecahedron. desirable.

A dispersion is prepared by dispersing the MgO crystal particles 92a obtained by any of the above methods in a solvent. Next, the dispersion is applied to the surface of the base layer 91 by a spray method, a screen printing method, an electrostatic coating method, or the like. Thereafter, the solvent is removed through a drying / firing process. Through the above steps, MgO crystal particles 92 a are fixed on the surface of the underlayer 91.

Further, the particle size of the primary particles of the crystal particles 92a can be controlled by the generation conditions of the crystal particles 92a. For example, when a precursor such as magnesium carbonate or magnesium hydroxide is produced by firing, the particle size can be controlled by controlling the firing temperature or firing atmosphere. Generally, the firing temperature can be selected in the range of 700 ° C to 1500 ° C. By setting the firing temperature to a relatively high temperature of 1000 ° C. or higher, the particle size can be controlled to about 0.3 to 2 μm. Further, by heating the precursor, a plurality of primary particles are aggregated or necked in the production process, and aggregated particles 92 can be obtained.

According to the experiments by the present inventors, the aggregated particles 92 in which a plurality of MgO crystal particles are agglomerated mainly confirms the effect of suppressing the “discharge delay” in the write discharge and the effect of improving the temperature dependency of the “discharge delay”. Has been. Aggregated particles 92 are excellent in initial electron emission characteristics as compared with underlayer 91. Therefore, in the present embodiment, the agglomerated particles 92 are arranged as an initial electron supply unit required at the time of discharge pulse rising.

The “discharge delay” is considered to be mainly caused by a shortage of the amount of initial electrons that are triggered from the surface of the underlayer 91 into the discharge space 16 at the start of discharge. Therefore, in order to contribute to the stable supply of initial electrons to the discharge space 16, the agglomerated particles 92 are dispersedly arranged on the surface of the base layer 91. As a result, abundant electrons are present in the discharge space 16 at the rise of the discharge pulse, and the discharge delay can be eliminated. Therefore, such initial electron emission characteristics enable high-speed driving with good discharge response even when the PDP 1 has a high definition. In the configuration in which the metal oxide aggregated particles 92 are disposed on the surface of the underlayer 91, in addition to the effect of mainly suppressing the “discharge delay” in the write discharge, the effect of improving the temperature dependency of the “discharge delay” is also achieved. can get.

[4. Change of Underlayer 91]
Next, changes in the underlayer 91 due to exposing the underlayer 91 to a reducing organic gas during sealing exhaust will be described. According to the study by the inventors, when the underlayer 91 is exposed to reducing organic gas during sealing exhaust, the ratio of the secondary electron emission coefficient γ to the krypton (Kr) and neon (Ne) of the underlayer 91 greatly changes. Turned out to be. Specifically, in PDP 1 in the present embodiment, the ratio of secondary electron emission coefficient γ to Kr and Ne: γ (Kr) / γ (Ne) is 0.02 or more and 0.12 or less.

When the ratio of the secondary electron emission coefficient γ is smaller than 0.02, the effect of exposure to the reducing organic gas described above cannot be obtained. On the other hand, when the ratio of the secondary electron emission coefficient γ is larger than 0.12, the underlayer 91 develops color. That is, a problem as a display device occurs. The color development of the underlayer 91 is due to the occurrence of oxygen defects. That is, the ratio of metal is increased by removing oxygen from the metal oxide included in the base layer 91. Therefore, the metal contained in the foundation layer 91 is colored.

So far, in the present embodiment, the case where the underlayer 91 is formed of two or more kinds of metal oxides selected from the group consisting of MgO, CaO, SrO, and BaO has been described. However, the phenomenon in which the ratio of the secondary electron emission coefficient γ is changed also occurs when the underlayer 91 is formed of only MgO. The presence or absence of the aggregated particles 92 does not affect the change in the ratio of the secondary electron emission coefficient γ.

When the underlayer 91 is formed of only MgO, the range of the ratio of the secondary electron emission coefficient γ to Kr and Ne is more preferably 0.02 or more and 0.50 or less.

When the underlayer 91 is made of two or more metal oxides selected from the group consisting of MgO, CaO, SrO, and BaO, the range of the ratio of the secondary electron emission coefficient γ to Kr and Ne is 0. It is more desirable that it is 0.02 or more and 0.12 or less.

Table 2 shows secondary electron emission coefficients for the rare gases Xe, Kr, Ar, Ne, and He of the underlayer 91. Note that the secondary electron emission coefficient is shown for both the conditions under which the reducing organic gas treatment for exposing the underlayer 91 to the reducing organic gas was performed and the conditions under which the reducing organic gas treatment was not performed. The underlayer 91 is composed only of MgO.

As shown in Table 2, the ionization energy of Xe is 12.1 eV. The ionization energy of Kr is 14 eV. The ionization energy of Ar is 15.8 eV. The ionization energy of Ne is 21.6 eV. The ionization energy of He is 24.6 eV. The greater the ionization energy, the more secondary electrons are emitted from the vacuum level to the deep level.

According to the experimental results, it has been found that the secondary electron emission coefficient for Xe, Kr, and Ar is greatly increased by performing the reducing organic gas treatment. This is considered to be because oxygen deficiency was formed in the underlayer 91 by exposing the underlayer 91 to the reducing organic gas during sealing exhaust. When oxygen vacancies are formed, a defect level is generated near the upper end of the valence band. The presence of electrons at the defect level increases the secondary electron emission coefficient for Xe, Kr, Ar, Ne, and He. However, the secondary electron emission coefficient for Ne and He is also affected by electrons in deeper levels. Therefore, the increase rate of the secondary electron emission coefficient becomes small. Therefore, it is considered that the secondary electron emission coefficient for Xe, Kr, and Ar mainly increased.

Next, a method for measuring the secondary electron emission coefficient for each rare gas of Xe, Kr, Ar, Ne, and He will be described.

The PDP 1 manufactured by the manufacturing method according to the present embodiment was used. Specifically, the discharge start voltage Vf between the scan electrode and the sustain electrode when the gas pressure is changed for each rare gas of Xe, Kr, Ar, Ne, and He by a device capable of replacing the gas in the PDP 1. (V) was measured. The measurement results are shown in FIG.

The inventors measured the results shown in FIG. 10, the formula shown by Penning et al., Η = α / E = (α / p) / (E / p), where η is the ionization number per 1V. And Paschen's law for each noble gas, α / p = Aexp [−B / (E / p)], where α is the ionization coefficient, E is the electric field strength, p Is a gas pressure.) The coefficients A and B were calculated.

Existing data is in the literature M. J. et al. Druyvesteyn and F.M. M.M. Penning, Revs. Mod. Phys. The data described in 12, 87 (1940) was used.

From the calculated Paschen's law formula using A and B and the Townsend spark discharge formula, γ [exp (αd) −1] = 1 (where d is the distance between electrodes), the discharge start voltage and gas The pressure relation was derived. Next, the value of γ was obtained by fitting so as to match the result of FIG.

The fitting was performed for Kr and Ne within a total pressure in the PDP of 200 Torr to 500 Torr.

[5. Evaluation]
A plurality of PDPs having different underlayer configurations were produced. The PDP was filled with 60 kPa Xe and Ne mixed gas (Xe 15%). Sample A is composed of MgO and CaO. Sample B is composed of MgO and SrO. Sample C is composed of MgO and BaO. Sample D is composed of MgO, CaO and SrO. Sample E is composed of MgO, CaO, and BaO. The comparative example is composed of MgO alone.

The maintenance voltage was measured for samples A to E. When the comparative example was 100, sample A was 90, sample B was 87, sample C was 85, sample D was 81, and sample E was 82. Samples A to E are PDPs manufactured by a normal manufacturing method. That is, samples A to E are PDPs manufactured by a manufacturing method that does not have a reducing organic gas introduction step.

When the Xe partial pressure of the discharge gas is increased from 10% to 15%, the luminance increases by about 30%, but in the comparative example, the sustain voltage increases by about 10%.

On the other hand, the sustain voltages of Sample A, Sample B, Sample C, Sample D, and Sample E were all reduced by about 10% to 20% compared to the comparative example.

Next, PDP 1 having base layer 91 having the same configuration as samples A to E was manufactured by the manufacturing method according to the present embodiment. The first temperature profile was used from the sealing step C1 to the discharge gas supply step C4.

As the reducing organic gas, propylene, cyclopropane, acetylene, and ethylene were used as an example. The sustain voltage of the PDP 1 according to the present embodiment was about 5% lower than those of the samples A to E.

Furthermore, before introducing the reducing organic gas, in the sealing step C1, nitrogen gas is allowed to flow as an inert gas so that the inside of the discharge space 16 is in a positive pressure state through the through-hole opened in the discharge space 16, and then When sealing was performed, it was about 5% to 7% lower than the sustain voltage of samples A to E.

[6. Effect]
The PDP 1 according to the present disclosure includes a front plate 2 and a back plate 10 disposed to face the front plate 2. The front plate 2 has a dielectric layer 8 and a protective layer 9 that covers the dielectric layer 8. The protective layer 9 includes one or more metal oxide layers selected from the group consisting of magnesium oxide, calcium oxide, strontium oxide, and barium oxide. The ratio of the secondary electron emission coefficient in the Ne gas of the protective layer 9 and the secondary electron emission coefficient in the Kr gas of the protective layer 9 is 0.02 or more and 0.12 or less.

According to the configuration of the present disclosure, the PDP 1 that can be driven at a low voltage can be provided.

The manufacturing method of the present disclosure is a manufacturing method of the PDP 1 having the discharge space 16 provided between the front plate 2 and the back plate 10. The front plate 2 has a dielectric layer 8 and a protective layer 9 that covers the dielectric layer 8. The front plate 2 has a dielectric layer 8 and a protective layer 9 that covers the dielectric layer 8. The protective layer 9 includes one or more metal oxide layers selected from the group consisting of magnesium oxide, calcium oxide, strontium oxide, and barium oxide. The ratio of the secondary electron emission coefficient in the Ne gas of the protective layer 9 and the secondary electron emission coefficient in the Kr gas of the protective layer 9 is 0.02 or more and 0.12 or less. In the manufacturing method, the protective layer 9 is exposed to the reducing organic gas by introducing a gas containing the reducing organic gas into the discharge space 16, and then the reducing organic gas is discharged from the discharge space 16. And enclosing the discharge gas in the discharge space 16.

Oxygen deficiency occurs in the protective layer 9 exposed to the reducing organic gas. Oxygen deficiency is considered to improve the secondary electron emission ability of the protective layer. Therefore, the PDP 1 manufactured by the manufacturing method of the present disclosure can reduce the sustain voltage.

Furthermore, the reducing organic gas is preferably a hydrocarbon-based gas that does not contain oxygen. This is because the reduction ability is enhanced by not containing oxygen.

Furthermore, the reducing organic gas is preferably at least one selected from the group consisting of acetylene, ethylene, methylacetylene, propadiene, propylene, cyclopropane, propane and butane. This is because the reducing organic gas is easy to handle in the manufacturing process. Furthermore, it is because said reducing organic gas is easy to decompose | disassemble.

In the present embodiment, a manufacturing method in which a gas containing a reducing organic gas is introduced into the discharge space 16 after the discharge space 16 is exhausted is exemplified. However, the gas containing the reducing organic gas can be introduced into the discharge space 16 by continuously supplying the gas containing the reducing organic gas to the discharge space 16 without exhausting the discharge space 16.

In the case where the protective layer 9 includes the metal oxide crystal particles 92a or the aggregated particles 92 in which a plurality of metal oxide crystal particles 92a are aggregated on the base layer 91, the protective layer 9 has a high charge holding capability and a high electron emission capability. Therefore, as a whole PDP 1, high-speed driving can be realized with a low voltage even with a high-definition PDP. In addition, high-quality image display performance with reduced lighting failure can be realized.

In the present embodiment, MgO is exemplified as the metal oxide crystal particle 92a. However, even with other single crystal particles, similar effects can be obtained by using crystal particles made of metal oxides such as Sr, Ca, Ba, Al, etc., which have high electron emission performance like MgO. Therefore, the metal oxide crystal particles 92a are not limited to MgO.

As described above, the embodiment has been described as an example of the technique in the present disclosure. To that end, the accompanying drawings and detailed description have been provided.

Therefore, the constituent elements described in the accompanying drawings and the detailed description may include constituent elements that are not essential for solving the problem. This is to illustrate the above technique. The non-essential components are described in the accompanying drawings and the detailed description, so that the non-essential components should not be recognized as essential.

Further, the above-described embodiment is for illustrating the technique in the present disclosure. Therefore, various modifications, replacements, additions, omissions, and the like can be made within the scope of the claims and the equivalents thereof.

The technology of the present disclosure is useful for a large screen display device.

1 PDP
DESCRIPTION OF SYMBOLS 2 Front plate 3 Front glass substrate 4

Scan electrode

4a, 5a

Transparent electrode

4b, 5b Metal bus electrode 5 Sustain electrode 6 Display electrode 8 Dielectric layer 9 Protection layer 10 Back plate 11 Back glass substrate 12 Data electrode 13 Base dielectric layer 14 Partition 15 Phosphor layer 16 Discharge space 91 Underlayer 92 Aggregated particle 92a Crystal particle

Claims

A front plate, and a back plate disposed opposite to the front plate,
The front plate has a dielectric layer and a protective layer covering the dielectric layer,
The protective layer includes one or more metal oxide layers selected from the group consisting of magnesium oxide, calcium oxide, strontium oxide, and barium oxide, a secondary electron emission coefficient in Ne gas of the protective layer, and The ratio of secondary electron emission coefficient in the Kr gas of the protective layer is 0.02 or more and 0.12 or less.
Plasma display panel.
The metal oxide layer is magnesium oxide, and a ratio of a secondary electron emission coefficient in the Ne gas of the protective layer to a secondary electron emission coefficient in the Kr gas of the protective layer is 0.02 or more and 0.05 or less. Is,
The plasma display panel according to claim 1.
A method of manufacturing a plasma display panel having a discharge space provided between a front plate and a back plate,
The front plate has a dielectric layer and a protective layer covering the dielectric layer,
The protective layer includes one or more metal oxide layers selected from the group consisting of magnesium oxide, calcium oxide, strontium oxide, and barium oxide, a secondary electron emission coefficient in Ne gas of the protective layer, and The ratio of secondary electron emission coefficient in the Kr gas of the protective layer is 0.02 or more and 0.12 or less,
Exposing the protective layer to the reducing organic gas by introducing a gas containing a reducing organic gas into the discharge space;
Next, discharging the reducing organic gas from the discharge space;
Next, enclosing a discharge gas in the discharge space,
A method for manufacturing a plasma display panel.
Sealing the periphery of the front plate and the back plate while keeping the discharge space at a positive pressure before introducing a gas containing a reducing organic gas into the discharge space;
The manufacturing method of the plasma display panel of Claim 3.
The reducing organic gas is a hydrocarbon gas that does not contain oxygen.
The manufacturing method of the plasma display panel of Claim 3.
The reducing organic gas is at least one selected from the group consisting of acetylene, ethylene, methylacetylene, propadiene, propylene, cyclopropane, propane and butane.
The manufacturing method of the plasma display panel of Claim 5.