JP2012064423A - Manufacturing method of plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a plasma display panel having a high-definition and high-brightness display performance, but reduced in its power consumption.SOLUTION: The method of manufacturing a plasma display panel includes a sealing step for oppositely arranging a front plate 2 and a back plate 10 and sealing together peripheral parts thereof with a seal member. A protection layer of the front plate 2 is formed from a metal oxide including at least two or more oxides selected from the group consisting of magnesium oxide, calcium oxide, strontium oxide and barium oxide. The metal oxide is a material such that in X-ray diffraction analysis, a peak arises between minimum and maximum diffraction angles generated by a unit body of the oxide included by the metal oxide in a specific azimuth surface. The method further includes a step for baking the first substrate under an atmosphere of gas containing a reductive organic gas after forming the protection layer of the first substrate.

Description

  The present invention relates to a method for manufacturing a plasma display panel used for a display device or the like.

  A plasma display panel (hereinafter referred to as a PDP) can realize a high definition and a large screen, and thus a 100-inch class television or the like has been commercialized. In recent years, PDP has been applied to high-definition televisions that have more than twice the number of scanning lines compared to the conventional NTSC system. In response to energy problems, efforts to further reduce power consumption and environmental issues There is also a growing demand for PDPs that do not contain lead components in consideration of the above.

  A PDP basically includes a front plate and a back plate. The front plate is a glass substrate of sodium borosilicate glass produced by the float process, a display electrode composed of a striped transparent electrode and a bus electrode formed on one main surface of the glass substrate, A dielectric layer that covers the display electrode and functions as a capacitor, and a protective layer made of magnesium oxide (MgO) formed on the dielectric layer.

  On the other hand, the back plate is a glass substrate, stripe-shaped address electrodes formed on one main surface thereof, a base dielectric layer covering the address electrodes, a partition formed on the base dielectric layer, The phosphor layer is formed between the barrier ribs and emits red, green and blue light.

  The front plate and the back plate are hermetically sealed with their electrode forming surfaces facing each other, and a discharge gas of neon (Ne) -xenon (Xe) is sealed at a pressure of 53 kPa to 80 kPa in a discharge space partitioned by a partition wall. ing. PDP discharges by selectively applying a video signal voltage to the display electrodes, and the ultraviolet rays generated by the discharge excite each color phosphor layer to emit red, green, and blue light, thereby realizing color image display is doing.

  In addition, such a PDP driving method includes an initialization period in which wall charges are adjusted so that writing is easy, a writing period in which writing discharge is performed according to an input image signal, and a discharge space in which writing is performed. A driving method having a sustain period in which display is performed by generating a sustain discharge is generally used. A period (subfield) obtained by combining these periods is repeated a plurality of times within a period (one field) corresponding to one frame of an image, thereby performing PDP gradation display.

  In such a PDP, the role of the protective layer formed on the dielectric layer of the front plate is to protect the dielectric layer from ion bombardment due to discharge and to emit initial electrons for generating address discharge. Etc. Protecting the dielectric layer from ion bombardment plays an important role in preventing an increase in discharge voltage, and emitting initial electrons for generating an address discharge is an address discharge error that causes image flickering. It is an important role to prevent.

  In order to increase the number of initial electrons emitted from the protective layer and reduce image flickering, for example, examples of adding impurities to the MgO protective layer and examples of forming MgO particles on the MgO protective layer are disclosed. (For example, see Patent Documents 1, 2, 3, 4, 5, etc.).

JP 2002-260535 A JP 11-339665 A JP 2006-59779 A JP-A-8-236028 JP-A-10-334809

  In recent years, high definition has been advanced in televisions, and a low-cost, low-power-consumption, high-brightness full HD (high definition) (1920 × 1080 pixels: progressive display) PDP is required in the market. Since the electron emission characteristics from the protective layer determine the image quality of the PDP, it is very important to control the electron emission characteristics.

  That is, in order to display a high-definition image, the number of pixels to be written increases even though the time of one field is constant. Therefore, in the writing period in the subfield, the pulse applied to the address electrode It is necessary to reduce the width. However, there is a time lag called “discharge delay” from the rise of the voltage pulse to the occurrence of discharge in the discharge space, so if the pulse width is narrowed, the probability that the discharge can be completed within the writing period is low. End up. As a result, lighting failure occurs, and the problem of deterioration in image quality performance such as flickering occurs.

  As described above, in order to advance the high definition and low power consumption of the PDP, it is necessary to simultaneously realize that the discharge voltage is not increased and that the image quality is improved by reducing defective lighting. There was a problem.

  The present invention has been made in view of such a problem, and an object of the present invention is to realize a PDP having high luminance display performance and capable of being driven at a low voltage.

  In order to achieve the above object, a PDP manufacturing method of the present invention is a method of manufacturing a PDP having a step of forming an electrode, a dielectric layer, and a protective layer on a substrate. It is formed of a metal oxide composed of at least two oxides selected from magnesium, calcium oxide, strontium oxide, and barium oxide, and the metal oxide constitutes the metal oxide in a specific orientation plane in X-ray diffraction analysis. And having a peak between the minimum diffraction angle and the maximum diffraction angle generated from the single oxide, and firing the protective layer in a gas atmosphere containing a reducing organic gas.

  In the method for producing the PDP of the present invention, the protective layer is formed of a metal oxide composed of at least two oxides selected from magnesium oxide, calcium oxide, strontium oxide, and barium oxide. In X-ray diffraction analysis, there is a peak between the minimum diffraction angle and the maximum diffraction angle generated from the single oxide constituting the metal oxide in a specific orientation plane, and the discharge space It is characterized by having a step of flowing a reducing organic gas into the discharge space so that the inside becomes a positive pressure state.

  Here, it is desirable that the reducing organic gas is a hydrocarbon-based gas not containing oxygen, and the reducing organic gas is selected from acetylene, ethylene, methylacetylene, propadiene, propylene, cyclopropane, propane, and butane. It is further desirable that the gas be selected.

  The protective layer is formed of a metal oxide composed of at least two oxides selected from magnesium oxide, calcium oxide, strontium oxide, and barium oxide, and the metal oxide has a specific orientation plane in X-ray diffraction analysis. Aggregates with a plurality of magnesium oxide crystal particles agglomerated on the undercoating film that has a peak between the minimum diffraction angle and the maximum diffraction angle generated from a single oxide constituting the metal oxide It is desirable that it is formed by adhering particles.

  According to the present invention, it is possible to reduce the discharge start voltage even when the Xe gas partial pressure of the discharge gas is increased in order to improve the secondary electron emission characteristics in the protective layer and increase the luminance. A PDP excellent in display performance capable of being driven with high brightness and low voltage can be realized.

The perspective view which shows the structure of PDP in embodiment of this invention Sectional drawing which shows the structure of the front plate of the PDP Flow chart showing the manufacturing method of the panel Flow chart showing the manufacturing method of the panel The figure which shows the X-ray-diffraction result in the base film of the PDP The figure which shows the X-ray-diffraction result in the base film of the other structure of the PDP Enlarged view for explaining the aggregated particles of the PDP The figure which shows the relationship between the discharge delay of the same PDP, and the calcium (Ca) density | concentration in a protective layer The figure which shows the result of having investigated about the electron emission performance and charge retention performance of the PDP Characteristic diagram showing the relationship between the particle size of crystal grains used in the PDP and the electron emission characteristics

  Hereinafter, a PDP according to an embodiment of the present invention will be described with reference to the drawings.

(1) Structure of PDP FIG. 1 is a perspective view showing the structure of the PDP in the embodiment of the present invention. The basic structure of the PDP is the same as that of a general AC surface discharge type PDP. As shown in FIG. 1, in the PDP 1, a front plate 2 as a first substrate made of a front glass substrate 3 and the like and a back plate 10 as a second substrate made of a back glass substrate 11 and the like are arranged to face each other. The peripheral part of the front plate 2 and the back plate 10 is hermetically sealed by a sealing member made of glass frit or the like. The discharge space 16 inside the sealed PDP 1 is filled with a discharge gas such as Xe and Ne at a pressure of 53 kPa to 80 kPa.

  On the front glass substrate 3 of the front plate 2, a pair of strip-shaped display electrodes 6 each composed of the scanning electrodes 4 and the sustain electrodes 5 and a plurality of black stripes (light shielding layers) 7 are arranged in parallel to each other. A dielectric layer 8 is formed on the front glass substrate 3 so as to cover the display electrodes 6 and the light-shielding layer 7 so as to hold charges and function as a capacitor. A protective layer 9 is further formed thereon. .

  On the back glass substrate 11 of the back plate 10, a plurality of strip-like address electrodes 12 are arranged in parallel to each other in a direction orthogonal to the scanning electrodes 4 and the sustain electrodes 5 of the front plate 2. Layer 13 is covering. Further, a partition wall 14 having a predetermined height is formed on the base dielectric layer 13 between the address electrodes 12 to divide the discharge space 16. In each groove between the barrier ribs 14, a phosphor layer 15 that emits red, green, and blue light by ultraviolet rays is sequentially applied. A discharge space is formed at a position where the scan electrode 4 and the sustain electrode 5 intersect with the address electrode 12, and a discharge space having red, green, and blue phosphor layers 15 arranged in the direction of the display electrode 6 is used for color display. Become a pixel.

FIG. 2 is a cross-sectional view showing a detailed configuration of the front plate 2 of the PDP 1 in the embodiment of the present invention, and FIG. 2 is shown upside down with respect to FIG. As shown in FIG. 2, a display electrode 6 and a light shielding layer 7 including scanning electrodes 4 and sustain electrodes 5 are formed in a pattern on a front glass substrate 3 manufactured by a float method or the like. Scan electrode 4 and sustain electrode 5 are made of transparent electrodes 4a and 5a made of indium tin oxide (ITO) or tin oxide (SnO ₂ ), respectively, and metal bus electrodes 4b and 5b formed on transparent electrodes 4a and 5a. It is comprised by. The metal bus electrodes 4b and 5b are used for the purpose of imparting conductivity in the longitudinal direction of the transparent electrodes 4a and 5a, and are formed of a conductive material whose main component is a silver (Ag) material.

  The dielectric layer 8 includes a first dielectric layer provided on the front glass substrate 3 so as to cover the transparent electrodes 4a and 5a, the metal bus electrodes 4b and 5b, and the light shielding layer 7, and a first dielectric layer. The second dielectric layer formed above has at least two layers, and a protective layer 9 is formed on the second dielectric layer.

  The protective layer 9 includes a base film 91 formed on the dielectric layer 8 and aggregated particles 92 in which a plurality of magnesium oxide (MgO) crystal particles 92 a are aggregated on the base film 91. In the protective layer 9, the base film 91 is formed of a metal oxide selected from magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO). The base film 91 of the protective layer 9 is made of a metal oxide composed of at least two oxides selected from magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO). It is desirable to form.

(2) PDP Manufacturing Method FIG. 3 is a flowchart showing the manufacturing process of the PDP in the embodiment of the present invention. Figures 3a and 3b show respective embodiments.

  As shown in FIG. 3a, a front plate creation step A1 and a back plate creation step B1, a firing step A2 for firing the front plate 2 created by the front plate creation step A1 in a gas atmosphere containing a reducing organic gas, and a back plate creation A frit coating step B2 in which a glass frit as a sealing member is applied to the outside of the image display area of the back plate 10 created in the step B1, and then pre-baked at a temperature of about 350 ° C. in order to remove resin components and the like of the glass frit. And the front plate 2 that has undergone the baking step A2 in the reducing organic gas atmosphere and the back plate 10 that has completed the frit coating step are pasted, and then the front plate 2 and the back plate 10 are sealed with glass frit, and then discharged. A sealing exhaust process C1 for exhausting the gas in the space 16, and a discharge gas supply process for supplying a discharge gas mainly composed of Ne and Xe into the evacuated panel. PDP is completed through 2.

  Moreover, the manufacturing process shown in FIG. 3B is adopted as another embodiment of the present invention. As shown in FIG. 3b, a glass frit as a sealing member is applied to the outside of the image display area of the back plate 10 created by the front plate creating process A1 and the back plate creating process B1 and the back plate creating process B1, and then the glass frit is applied. After attaching the frit coating step B2 that is pre-baked at a temperature of about 350 ° C. to remove the resin component, etc., the front plate 2 created by the front plate creation step A1, and the back plate 10 that has finished the frit coating step A reducing organic gas introduction step C0 for flowing a reducing organic gas through a through-hole opened in the discharge space 16 provided in the back plate 10 so that the inside of the discharge space is in a positive pressure state, and the front plate 2 and the back plate 10 are A sealing and exhausting step C1 in which a step of sealing with glass frit and a step of exhausting the gas in the discharge space 16 are continued, and Ne and PDP is completed the discharge gas mainly composed of e via the discharge gas supplying step C2 supplies.

  First, the front plate creation process will be described. On the front glass substrate 3, the scan electrode 4, the sustain electrode 5, and the light shielding layer 7 are formed. Transparent electrodes 4a and 5a and metal bus electrodes 4b and 5b constituting scan electrode 4 and sustain electrode 5 are formed by patterning using a photolithography method or the like. The transparent electrodes 4a and 5a are formed using a thin film process or the like, and the metal bus electrodes 4b and 5b are solidified by baking a paste containing a silver (Ag) material at a predetermined temperature. Similarly, the light shielding layer 7 is also formed by screen printing a paste containing a black pigment or by forming a black pigment on the entire surface of the glass substrate and then patterning and baking using a photolithography method.

  Next, a dielectric paste is applied on the front glass substrate 3 by a die coating method or the like so as to cover the scan electrode 4, the sustain electrode 5, and the light shielding layer 7, thereby forming a dielectric paste (dielectric material) layer. After the dielectric paste is applied, the surface of the applied dielectric paste is leveled by leaving it to stand for a predetermined time, so that a flat surface is obtained. Thereafter, the dielectric paste layer is formed by baking and solidifying the dielectric paste layer to cover the scan electrode 4, the sustain electrode 5, and the light shielding layer 7. The dielectric paste is a paint containing a dielectric material such as glass powder, a binder and a solvent.

  Next, a base film 91 is formed on the dielectric layer 8. In the embodiment of the present invention, the base film 91 is made of at least two oxides selected from magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO). It is formed of a metal oxide.

  The base film 91 is formed into a thin film using a pellet made of a single material of magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO), or a pellet obtained by mixing these materials. Formed by the method. As a thin film forming method, a known method such as an electron beam evaporation method, a sputtering method, or an ion plating method can be applied. As an example, 1 Pa is considered as the upper limit of the pressure that can actually be taken in the sputtering method and 0.1 Pa in the electron beam evaporation method, which is an example of the evaporation method. In addition, as an atmosphere during film formation of the base film 91, a predetermined electron emission characteristic is obtained by adjusting the atmosphere during film formation in a sealed state that is shut off from the outside in order to prevent moisture adhesion and adsorption of impurities. A base film 91 made of a metal oxide having the above can be formed.

  Next, the agglomerated particles 92 of the magnesium oxide (MgO) crystal particles 92a deposited on the base film 91 will be described. These crystal particles 92a can be manufactured by any one of the following vapor phase synthesis method or precursor baking method. In the gas phase synthesis method, a magnesium metal material having a purity of 99.9% or more is heated in an atmosphere filled with an inert gas, and a small amount of oxygen is introduced into the atmosphere to directly oxidize magnesium, thereby oxidizing the material. Magnesium (MgO) crystal particles 92a can be produced.

On the other hand, in the precursor firing method, the crystal particles 92a can be produced by the following method. In the precursor firing method, a magnesium oxide (MgO) precursor is uniformly fired at a high temperature of 700 ° C. or higher, and this is gradually cooled to obtain magnesium oxide (MgO) crystal particles 92a. 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 ) can be selected. Depending on the selected compound, it may usually take the form of a hydrate, but such a hydrate may be used.

  These compounds are adjusted so that the purity of magnesium oxide (MgO) obtained after calcination is 99.95% or more, preferably 99.98% or more. If these compounds contain a certain amount or more of various impurity elements such as alkali metals, B, Si, Fe, and Al, unnecessary interparticle adhesion and sintering occur during heat treatment, and highly crystalline magnesium oxide ( This is because it is difficult to obtain MgO) crystal particles. For this reason, it is necessary to adjust the precursor in advance by removing the impurity element.

  The magnesium oxide (MgO) crystal particles 92a obtained by any of the above methods are dispersed in a solvent, and the dispersion is dispersed and dispersed on the surface of the base film 91 by spraying, screen printing, electrostatic coating, or the like. Let Thereafter, the solvent is removed through a drying / firing process, and the magnesium oxide (MgO) crystal particles 92 a can be fixed on the surface of the base film 91.

  Through such a series of steps, predetermined components (scanning electrode 4, sustaining electrode 5, light shielding layer 7, dielectric layer 8, and protective layer 9) are formed on front glass substrate 3, and front plate 2 is completed.

  On the other hand, in the back plate creating process, the back plate 10 is formed as follows. First, the structure for the address electrode 12 is formed by a method of screen printing a paste containing silver (Ag) material on the rear glass substrate 11 or a method of patterning using a photolithography method after forming a metal film on the entire surface. A material layer to be a material is formed. Thereafter, the address electrode 12 is formed by firing at a predetermined temperature. Next, a dielectric paste is applied on the rear glass substrate 11 on which the address electrodes 12 are formed by a die coating method or the like so as to cover the address electrodes 12 to form a dielectric paste layer. Thereafter, the base dielectric layer 13 is formed by firing the dielectric paste layer. The dielectric paste is a paint containing a dielectric material such as glass powder, a binder and a solvent.

  Next, a partition wall forming paste containing a partition wall material is applied on the base dielectric layer 13 and patterned into a predetermined shape to form a partition wall material layer. Then, the partition 14 is formed by baking at a predetermined temperature. Here, as a method of patterning the partition wall paste applied on the base dielectric layer 13, a photolithography method or a sand blast method can be used. Then, the phosphor layer 15 is formed by applying and baking a phosphor paste containing a phosphor material on the base dielectric layer 13 between the adjacent barrier ribs 14 and on the side surfaces of the barrier ribs 14. Through the above steps, the back plate 10 having predetermined components on the back glass substrate 11 is completed.

  Thereafter, a glass frit as a sealing member is applied to the outside of the image display area of the back plate 10 created by the back plate creating process, and then pre-baked at a temperature of about 350 ° C. in order to remove the resin component and the like of the glass frit. A frit coating process is performed.

Here, the sealing member is preferably a frit mainly composed of bismuth oxide or vanadium oxide. Examples of the frit containing bismuth oxide as a main component include, for example, 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. In addition, 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 , cordierite is added to a V ₂ O ₅ —BaO—TeO—WO glass material. Things can be used.

  Further, in the present invention, in the manufacturing process shown in FIG. 3, after the formation of the protective layer on the first substrate, a firing step A2 is performed in which the first substrate is fired in a gas atmosphere containing a reducing organic gas. A sealing and exhausting process C1 in which one substrate and a second substrate are sealed with the glass frit, and then the gas in the discharge space is exhausted. Then, a discharge gas mainly containing Ne and Xe is evacuated into the panel. By performing the discharge gas supply process C2 for supplying the PDP, the sustain discharge voltage of the PDP can be further reduced. This sealing / exhaust process will be described later.

(3) Protective layer Next, the detail of the protective layer 9 in embodiment of this invention is demonstrated. In the PDP according to the embodiment of the present invention, as shown in FIG. 2, the protective layer 9 includes a base film 91 formed on the dielectric layer 8, and a magnesium oxide (MgO) crystal deposited on the base film 91. It is constituted by aggregated particles 92 in which a plurality of particles 92a are aggregated. Further, the base film 91 is formed of a metal oxide made of at least two oxides selected from magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO), In the X-ray diffraction analysis of the surface of the base film 91, the metal oxide has a peak between the minimum diffraction angle and the maximum diffraction angle generated from a single oxide constituting the metal oxide of a specific orientation plane. Yes.

  FIG. 4 is a diagram showing an X-ray diffraction result on the surface of the base film 91 constituting the protective layer 9 of the PDP in the embodiment of the present invention. FIG. 4 also shows the results of X-ray diffraction analysis of magnesium oxide (MgO) alone, calcium oxide (CaO) alone, strontium oxide (SrO) alone, and barium oxide (BaO) alone.

  In FIG. 4, the horizontal axis represents the Bragg diffraction angle (2θ), and the vertical axis represents the intensity of the X-ray diffraction wave. The unit of the diffraction angle is shown in degrees when one round is 360 degrees, and the intensity is shown in an arbitrary unit. In the figure, the crystal orientation plane which is a specific orientation plane is shown in parentheses. As shown in FIG. 4, in the crystal orientation plane (111), the diffraction angle is 32.2 degrees for calcium oxide (CaO) alone, the diffraction angle is 36.9 degrees for magnesium oxide (MgO) alone, and strontium oxide (SrO) alone. Shows a peak at a diffraction angle of 30.0 degrees, and barium oxide (BaO) alone has a peak at a diffraction angle of 27.9 degrees.

  In the PDP in the embodiment of the present invention, at least two or more selected from magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO) are used as the base film 91 of the protective layer 9. It is formed of a metal oxide made of the oxide.

  FIG. 4 shows an X-ray diffraction result when the single component constituting the base film 91 is two components. That is, the X-ray diffraction result of the base film 91 formed using magnesium oxide (MgO) and calcium oxide (CaO) alone was formed using point A, magnesium oxide (MgO) and strontium oxide (SrO) alone. The X-ray diffraction result of the base film 91 is indicated by B point, and further, the X-ray diffraction result of the base film 91 formed using magnesium oxide (MgO) and barium oxide (BaO) alone is indicated by C point.

  That is, the point A is a diffraction angle of 36.9 degrees of the magnesium oxide (MgO) alone, which is the maximum diffraction angle of the single oxide, in the crystal orientation plane (111) as the specific orientation plane, and the oxidation which is the minimum diffraction angle. A peak exists at a diffraction angle of 36.1 degrees, which is between the diffraction angle of 32.2 degrees of calcium (CaO) alone. Similarly, peaks at points B and C exist at 35.7 degrees and 35.4 degrees between the maximum diffraction angle and the minimum diffraction angle, respectively.

  Further, FIG. 5 shows the X-ray diffraction result when the single component constituting the base film 91 is three or more components, as in FIG. That is, FIG. 5 shows the results when magnesium oxide (MgO), calcium oxide (CaO), and strontium oxide (SrO) are used as the single component, point D, magnesium oxide (MgO), calcium oxide (CaO), and oxidation. The results when barium (BaO) is used are indicated by point E, and the results when calcium oxide (CaO), strontium oxide (SrO) and barium oxide (BaO) are used are indicated by point F.

  That is, the point D is a crystal orientation plane (111) as a specific orientation plane, and a diffraction angle of 36.9 degrees of magnesium oxide (MgO) as a maximum diffraction angle of a single oxide and an oxidation level as a minimum diffraction angle. A peak exists at a diffraction angle of 33.4 degrees, which is between the diffraction angle of 30.0 degrees of strontium (SrO) alone. 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.

  Therefore, in the X-ray diffraction analysis of the surface of the base film 91 of the metal oxide constituting the base film 91, the base film 91 of the PDP in the embodiment of the present invention has two components or three components as a single component. A peak exists between the minimum diffraction angle and the maximum diffraction angle of a peak generated from a single oxide constituting a metal oxide having a specific orientation plane.

  In the above description, (111) has been described as the crystal orientation plane as the specific orientation plane, but the peak position of the metal oxide is the same as that described above when other crystal orientation planes are also targeted.

  The depth from the vacuum level of calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO) exists in a shallow region as compared with magnesium oxide (MgO). Therefore, when the PDP 1 is driven, when electrons existing in the energy levels of calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO) transition to the ground state of the xenon (Xe) ion, Auger It is considered that the number of electrons emitted due to the effect increases as compared with the case of transition from the energy level of magnesium oxide (MgO).

  Further, as described above, the base film 91 according to the embodiment of the present invention has a peak between the minimum diffraction angle and the maximum diffraction angle of the peak generated from the single oxide constituting the metal oxide. I have to. As a result of the X-ray diffraction analysis, the metal oxide having the characteristics shown in FIGS. 4 and 5 has its energy level between the single oxides constituting them. Accordingly, the energy level of the base film 91 is also present between the single oxides, and the amount of energy acquired by other electrons due to the Auger effect can be set to an amount sufficient to be released beyond the vacuum level. .

  As a result, the base film 91 can exhibit better secondary electron emission characteristics as compared with magnesium oxide (MgO) alone, and as a result, the discharge sustaining voltage can be reduced. Therefore, particularly when the partial pressure of xenon (Xe) as the discharge gas is increased in order to increase the luminance, it is possible to reduce the discharge voltage and realize a low-voltage and high-luminance PDP.

  Here, in the PDP according to the embodiment of the present invention, the discharge sustaining voltage of the PDP when the configuration of the base film 91 is changed will be described. First, as a sample according to the present invention, sample A (underlying film 91 is a metal oxide of magnesium oxide (MgO) and calcium oxide (CaO)), and sample B (underlying film 91 is magnesium oxide (MgO) and strontium oxide (SrO). ), Sample C (the base film 91 is a metal oxide of magnesium oxide (MgO) and barium oxide (BaO)), sample D (the base film 91 is magnesium oxide (MgO), calcium oxide (CaO)) And metal oxide by strontium oxide (SrO)), sample E (underlying film 91 is a metal oxide by magnesium oxide (MgO), calcium oxide (CaO) and barium oxide (BaO)), and as a comparative example, Prepared the base film 91 composed of magnesium oxide (MgO) alone It was.

  When the sustaining voltage is measured for these samples A to E, when the comparative example is 100, sample A is 90, sample B is 87, sample C is 85, sample D is 81, and sample E is 82. The value is shown.

  When the partial pressure of the discharge gas xenon (Xe) is increased from 10% to 15%, the luminance increases by about 30%. However, in the comparative example in which the base film 91 is made of magnesium oxide (MgO) alone, the discharge is maintained. The voltage increases about 10%. On the other hand, in the PDP according to the embodiment of the present invention, the discharge sustaining voltage can be reduced by about 10% to 20% in all of the samples A, B, C, D, and E as compared with the comparative example. Therefore, the discharge start voltage can be set within the normal operation range, and a high-luminance and low-voltage drive PDP can be realized.

  Calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO) are highly reactive as a single substance, and thus easily react with impurities, and as a result, the electron emission performance tends to decrease. By forming the structure, the reactivity is reduced, and the crystal structure is formed with less impurity contamination and less oxygen vacancies, so that excessive emission of electrons during driving of the PDP is suppressed, and low voltage driving In addition to the coexistence effect of secondary electron emission performance, the effect of moderate charge retention characteristics is also exhibited. This charge retention characteristic is particularly effective for retaining wall charges stored in the initialization period and preventing a write failure in the write period and performing a reliable write discharge.

  Next, the agglomerated particles 92 in which a plurality of magnesium oxide (MgO) crystal particles 92a are aggregated provided on the base film 91 in the embodiment of the present invention will be described in detail. Aggregated particles 92 of magnesium oxide (MgO) have been confirmed by experiments of the present inventors mainly to suppress the “discharge delay” in the write discharge and to improve the temperature dependence of the “discharge delay”. Therefore, in the embodiment of the present invention, the aggregated particles 92 are arranged as an initial electron supply unit required at the time of rising of the discharge pulse by utilizing the property that the advanced initial electron emission characteristics are superior to the base film 91.

  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 base film 91 being discharged 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 aggregated particles 92 of magnesium oxide (MgO) are dispersedly arranged on the surface of the base film 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 base film 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 obtained. It is done.

  As described above, the PDP 1 according to the embodiment of the present invention includes the base film 91 that achieves both low-voltage driving and charge retention, and the magnesium oxide (MgO) aggregated particles 92 that have the effect of preventing discharge delay. Thus, as a whole PDP 1, high-definition PDP can be driven at high speed with a low voltage, and high-quality image display performance with suppressed lighting failure can be realized.

  In the embodiment of the present invention, the aggregated particles 92 in which a plurality of crystal particles 92 a are aggregated are discretely dispersed on the base film 91, and a plurality of particles are adhered so as to be distributed almost uniformly over the entire surface. is doing. FIG. 6 is an enlarged view for explaining the agglomerated particles 92.

  Aggregated particles 92 are those in which crystal particles 92a having a predetermined primary particle size are aggregated or necked, as shown in FIG. 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. The particle size of the agglomerated particles 92 is about 1 μm, and the crystal particles 92a preferably have a polyhedral shape having seven or more surfaces such as a tetrahedron and a dodecahedron.

  Moreover, 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 an MgO precursor such as magnesium carbonate or magnesium hydroxide is calcined and produced, the particle size can be controlled by controlling the calcining temperature and the calcining atmosphere. Generally, the firing temperature can be selected in the range of 700 ° C. to 1500 ° C., but by setting the firing temperature to a relatively high 1000 ° C. or higher, the particle size can be controlled to about 0.3 to 2 μm. is there. Furthermore, by obtaining the crystal particles 92a by heating the MgO precursor, a plurality of primary particles are bonded to each other by a phenomenon called agglomeration or necking in the production process, whereby the agglomerated particles 92 can be obtained.

  FIG. 7 shows the discharge delay in the protective layer 9 in the case of using the base film 91 made of a metal oxide of magnesium oxide (MgO) and calcium oxide (CaO) in the PDP in the embodiment of the present invention. It is a figure which shows the relationship with a calcium (Ca) density | concentration. The base film 91 is composed of a metal oxide composed of magnesium oxide (MgO) and calcium oxide (CaO), and the metal oxide has a magnesium oxide (MgO) peak in the X-ray diffraction analysis on the surface of the base film 91. A peak exists between the diffraction angle at which the peak is generated and the diffraction angle at which the peak of calcium oxide (CaO) is generated. FIG. 7 shows the case where only the base film 91 is used as the protective layer 9 and the case where the aggregated particles 92 are arranged on the base film 91, and the discharge delay is caused by calcium (Ca) contained in the base film 91. The case where it is not done is shown as a standard.

  Further, the electron emission performance is a numerical value indicating that the larger the electron emission performance, the greater the amount of electron emission, and is expressed by the initial electron emission amount determined by the surface state, the gas type, and the state. The initial electron emission amount can be measured by a method of measuring the amount of electron current emitted from the surface by irradiating the surface with ions or an electron beam. However, the evaluation of the surface of the front plate 2 of the PDP 1 can be performed nondestructively. With difficulty. Therefore, the method described in JP 2007-48733 A was used. That is, among the delay times at the time of discharge, a numerical value called a statistical delay time, which is a measure of the likelihood of occurrence of discharge, is measured, and when the reciprocal is integrated, a numerical value corresponding to the initial electron emission amount is obtained.

  Therefore, this numerical value is used for evaluation. The delay time at the time of discharge means the time of discharge delay when the discharge is delayed from the rising edge of the pulse, and the discharge delay is the time when the initial electrons that trigger when the discharge is started are discharged from the surface of the protective layer 9 to the discharge space. It is considered as a main factor that it is difficult to be released into the inside.

  As is apparent from FIG. 7, in the case of only the base film 91 and in the case where the aggregated particles 92 are arranged on the base film 91, the discharge delay increases as the calcium (Ca) concentration increases in the case of the base film 91 alone. On the other hand, it can be seen that by disposing the agglomerated particles 92 on the base film 91, the discharge delay can be significantly reduced, and the discharge delay hardly increases even when the calcium (Ca) concentration is increased.

  Next, the results of experiments conducted to confirm the effect of the protective layer 9 having the aggregated particles 92 in the embodiment of the present invention will be described. First, a PDP having a base film 91 having a different structure and agglomerated particles 92 provided on the base film 91 was made as a prototype. Prototype 1 is a PDP in which a protective layer 9 made only of a magnesium oxide (MgO) base film 91 is formed. Prototype 2 is a protective layer 9 made only of a base film 91 in which magnesium oxide (MgO) is doped with impurities such as Al and Si. Prototype 3 is a PDP in which a protective layer 9 is formed by spraying and adhering only primary particles of magnesium oxide (MgO) crystal particles 92a on a base film 91 made of magnesium oxide (MgO).

  On the other hand, the prototype 4 is the PDP in the embodiment of the present invention, and the above-described sample A is used as the protective layer 9. That is, the protective layer 9 includes a base film 91 made of a metal oxide of magnesium oxide (MgO) and calcium oxide (CaO), and aggregated particles 92 obtained by aggregating crystal particles 92a on the base film 91 over the entire surface. So that it is distributed almost uniformly. In the X-ray diffraction analysis of the surface of the base film 91, the base film 91 is set so that a peak exists between the minimum diffraction angle and the maximum diffraction angle of a peak generated from a single oxide constituting the base film 91. ing. That is, the minimum diffraction angle in this case is 32.2 degrees for calcium oxide (CaO), the maximum diffraction angle is 36.9 degrees for magnesium oxide (MgO), and the peak of the diffraction angle of the base film 91 is 36.1 degrees. To exist.

  The electron emission performance and charge retention performance of these PDPs were examined, and the results are shown in FIG. The electron emission performance is evaluated by the above-described method, and the charge retention performance is measured by using a voltage (hereinafter referred to as Vscn lighting voltage) applied to the scan electrode necessary for suppressing the charge emission phenomenon when the PDP is manufactured. ) Voltage value was used. That is, a lower Vscn lighting voltage indicates a higher charge retention capability. This makes it possible to use components having a low withstand voltage and a small capacity as the power source and each electrical component in designing the PDP. In the current product, an element having a withstand voltage of about 150 V is used as a semiconductor switching element such as a MOSFET for sequentially applying a scanning voltage to the panel, and the Vscn lighting voltage is 120 V or less in consideration of variation due to temperature. It is desirable to keep it at a minimum.

  FIG. 8 is a diagram showing the results of examining the electron emission performance and the charge retention performance of the PDP in the embodiment of the present invention. As is apparent from FIG. 8, a prototype in which aggregated particles 92 obtained by agglomerating magnesium oxide (MgO) crystal particles 92a are dispersed on base film 91 in the embodiment of the present invention and uniformly distributed over the entire surface. 4 is a characteristic that in the evaluation of the charge retention performance, the Vscn lighting voltage can be reduced to 120 V or less, and the electron emission performance is much better than that of the prototype 1 in the case of a protective layer made only of magnesium oxide (MgO). Can be obtained.

  In general, the electron emission capability and the charge retention capability of the protective layer of the PDP are contradictory. For example, it is possible to improve the electron emission performance by changing the film forming conditions of the protective layer, or by forming a film by doping impurities such as Al, Si, and Ba in the protective layer. The Vscn lighting voltage also increases.

  In the PDP of the prototype 4 in which the protective layer 9 is formed in the embodiment of the present invention, the electron emission capability is 8 times or more compared to the prototype 1 using the protective layer only of magnesium oxide (MgO). The charge holding ability can be obtained with a Vscn lighting voltage of 120 V or less. Therefore, it is useful for PDPs with a large number of scanning lines and a small cell size due to high definition, satisfying both electron emission capability and charge retention capability, and reducing discharge delay and good image display Can be realized.

  Next, the particle size of the crystal particles used in the protective layer 9 of the PDP according to the present invention will be described in detail. In the following description, the particle diameter means an average particle diameter, and the average particle diameter means a volume cumulative average diameter (D50).

  FIG. 9 shows the experimental results of examining the electron emission performance of the prototype 4 of the present invention described with reference to FIG. 8 by changing the particle size of the crystal particles 92a. In FIG. 9, the particle diameter of the crystal particle 92 a was measured by observing the crystal particle 92 a with an SEM. As shown in FIG. 9, it can be seen that when the particle size is reduced to about 0.3 μm, the electron emission performance is lowered, and when it is approximately 0.9 μm or more, high electron emission performance is obtained.

  Incidentally, in order to increase the number of electrons emitted in the discharge cell, it is desirable that the number of crystal particles 92a per unit area on the base film 91 is large. The crystal particles 92a are present in the portion corresponding to the top of the partition wall 14 of the back plate 10 that is in intimate contact with the protective layer 9 of the back surface 10, thereby damaging the top of the partition wall 14 and the material is deposited on the phosphor layer 15. It has been found that the phenomenon that the corresponding cell does not normally turn on and off by getting on. The phenomenon of the partition wall breakage is unlikely to occur unless the crystal particle 92a is present at the portion corresponding to the top of the partition wall 14. Therefore, the probability of the breakage of the partition wall 14 increases as the number of crystal particles 92a attached increases. From this point of view, when the crystal particle diameter is increased to about 2.5 μm, the probability of partition wall breakage increases rapidly, and when the crystal particle diameter is smaller than 2.5 μm, the probability of partition wall breakage is kept relatively small. be able to.

  From the above results, in the PDP according to the embodiment of the present invention, if the aggregated particles 92 having a particle size in the range of 0.9 μm to 2 μm are used as the aggregated particles 92, the above-described effects of the present invention can be stably achieved. It turned out to be obtained. In addition, although it demonstrated using the magnesium oxide (MgO) particle | grains as a crystal particle, metal oxides, such as Sr, Ca, Ba, Al, etc. which have high electron emission performance similarly to magnesium oxide (MgO) also in this other single crystal particle. Since the same effect can be obtained even if crystal grains made of a material are used, the particle type is not limited to magnesium oxide (MgO).

(4) Sealing / Exhausting Step Next, the sealing / exhausting step in the embodiment of the present invention will be described. In the manufacturing process shown in FIG. 3a, after the protective layer is formed on the first substrate, a firing step A2 is performed in which the first substrate is baked in a gas atmosphere containing a reducing organic gas, and the first substrate and the second substrate are separated. A sealing exhaust process C1 for sealing with the glass frit and then exhausting the gas in the discharge space, and a discharge gas supplying process for supplying a discharge gas mainly composed of Ne and Xe into the evacuated panel. By performing C2, the sustain discharge voltage of the PDP can be further reduced.

  Here, as shown in FIG. 3b as another embodiment of the present invention, the discharge is provided on the second substrate after the A2 step is not performed and the first substrate and the second substrate are arranged to face each other. There is a manufacturing method in which a reducing organic gas introduction step C0 is provided in which a reducing organic gas flows so that the inside of the discharge space is in a positive pressure state through a through hole that opens to the space. Even in this case, the sustain discharge voltage of the PDP can be further reduced.

  As shown in Table 1, the reducing organic gas used in the present invention is preferably a CH-based organic gas having a molecular weight of 58 or less and having a large reducing power, and the reducing organic gas selected from these reducing organic gases. Is mixed with a rare gas or nitrogen gas to produce a gas containing a reducing organic gas, and the reducing step is performed so that the firing step A2 in a gas atmosphere containing the reducing gas or the discharge space is in a positive pressure state. A reducing organic gas introduction step C0 in which an organic gas is supplied is performed. The firing temperature is preferably about 300 ° C. or higher.

  In Table 1, in the item of the vapor pressure of each reducing organic gas, “◯” mark is given to a gas of 100 kPa (0 ° C.) or higher, and “X” mark is given to a gas lower than 100 kPa (0 ° C.). It is attached. Further, in the item of boiling point, a gas “0 ° C. or lower” is marked with “◯”, and a gas higher than 0 ° C. is marked with “x”. From the viewpoint of easy handling of organic gas in the manufacturing process of PDP, a reducing organic gas that can be supplied in a gas cylinder is desirable. From the viewpoint of easy handling in the manufacturing process, the vapor pressure is 100 kPa (0 ° C. ) The above reducing organic gas, the reducing organic gas having a boiling point of 0 ° C. or less, or the reducing organic gas having a small molecular weight is desirable.

  Furthermore, in the present invention, considering the above steps, a reducing organic gas that is easily decomposed is desirable, and in Table 1, “◯” marks are given to easily decomposed gases as items that are easily decomposed.

  Considering the ease of handling in the above manufacturing process and the case of partial remaining, the reducing organic gas is oxygen selected from acetylene, ethylene, methylacetylene, propadiene, propylene, and cyclopropane. A hydrocarbon-based gas containing no hydrogen is desirable, and a reducing organic gas selected from these reducing organic gases may be mixed with a rare gas or nitrogen gas.

As a result of experiments conducted by the present inventors, for example, when C ₃ H ₆ propylene gas or cyclopropane gas is used in the chemical formula, C ₂ H ₂ acetylene gas is used in the chemical formula, and C ₂ H _{4 in the} chemical formula. It was found that the sustaining voltage can be further reduced by about 3 to 5% for the above-mentioned samples A to E when the ethylene gas is used.

  The mixing ratio of the reducing organic gas to be mixed with the rare gas or nitrogen gas may be determined as the lower limit ratio according to the combustion range of the reducing organic gas to be used. Used by mixing with nitrogen gas. In addition, if the concentration of these reducing organic gases is too high, the organic components are polymerized to form a polymer that remains in the panel and affects the panel characteristics. It is necessary to appropriately adjust the mixing ratio according to the gas component.

  As described above, according to the present invention, the protective layer 9 is formed of a metal oxide composed of at least two oxides selected from magnesium oxide, calcium oxide, strontium oxide, and barium oxide, and The sustain discharge voltage of the PDP can be greatly reduced by performing a firing step of firing the first substrate in a gas atmosphere containing the reducing organic gas after forming the protective layer on the substrate.

  As described above, the present invention is useful in realizing a PDP having high image quality display performance and low power consumption.

1 PDP
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 7 Black stripe (light shielding layer)
DESCRIPTION OF SYMBOLS 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 91 Base film 92 Aggregated particle 92a Crystal particle

Claims (5)

A method for manufacturing a plasma display panel comprising a step of forming an electrode, a dielectric layer, and a protective layer on a substrate,
The protective layer is formed of a metal oxide composed of at least two oxides selected from magnesium oxide, calcium oxide, strontium oxide, and barium oxide,
In the X-ray diffraction analysis, the metal oxide has a peak between the minimum diffraction angle and the maximum diffraction angle generated from the single oxide constituting the metal oxide in a specific orientation plane,
And the manufacturing method of the plasma display panel characterized by having the process of baking the said protective layer in the gas atmosphere containing a reducing organic gas. A method for manufacturing a plasma display panel, comprising: forming an electrode, a dielectric layer, and a protective layer on a substrate; and placing and sealing the substrate and the other substrate so as to have a discharge space. There,
The protective layer is formed of a metal oxide composed of at least two oxides selected from magnesium oxide, calcium oxide, strontium oxide, and barium oxide,
In the X-ray diffraction analysis, the metal oxide has a peak between the minimum diffraction angle and the maximum diffraction angle generated from the single oxide constituting the metal oxide in a specific orientation plane,
A method of manufacturing a plasma display panel, comprising: a step of flowing a reducing organic gas into the discharge space so that the inside of the discharge space is in a positive pressure state after the opposing arrangement. The method of manufacturing a plasma display panel according to claim 1, wherein the reducing organic gas is a hydrocarbon gas that does not contain oxygen. 3. The plasma display panel according to claim 1, wherein the reducing organic gas is a gas selected from acetylene, ethylene, methylacetylene, propadiene, propylene, cyclopropane, propane, and butane. Manufacturing method. The protective layer is formed of a metal oxide composed of at least two oxides selected from magnesium oxide, calcium oxide, strontium oxide, and barium oxide, and the metal oxide has a specific orientation plane in X-ray diffraction analysis. The base film is a film having a peak between the minimum diffraction angle and the maximum diffraction angle generated from the single oxide constituting the metal oxide, and a plurality of magnesium oxide crystal particles are formed on the base film. 3. The method for manufacturing a plasma display panel according to claim 1, wherein the aggregated particles are formed by adhering them.

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