JP2010037609A - Film forming material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film forming material (vapor deposition material) for forming a protective layer of an excellent plasma display panel, to achieve the plasma display panel for displaying an excellent image. <P>SOLUTION: Disclosed is the film forming material 202 which is fed to a film forming apparatus through a chute (material supply passage), wherein the shape is a columnar shape in which the ratio (t/ϕ) of the diameter (ϕ) to the thickness (t) is ≥0.5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a film forming material for forming a film by an electron beam evaporation method, and more particularly to a polycrystalline MgO film forming material for forming an MgO film of an AC type plasma display panel.

  Plasma display panels (hereinafter also referred to as PDPs) are roughly classified into AC types and DC types in terms of driving, and there are two types of discharge types: surface discharge type and counter discharge type. At present, the mainstream is the AC type surface discharge type because of the simplicity of manufacturing and manufacturing.

  In this AC type surface discharge PDP structure, at least a pair of substrates transparent at the front side are arranged opposite to each other so that a discharge space is formed between the substrates, and a partition for partitioning the discharge space into a plurality is arranged on the substrate. In addition, a plurality of discharge cells are configured by arranging an electrode group on the substrate so that a discharge is generated in the discharge space partitioned by the barrier ribs, and providing phosphors that emit red, green, and blue light emitted by the discharge. However, phosphors are excited by vacuum ultraviolet light having a short wavelength generated by discharge, and red, green, and blue visible light is emitted from red, green, and blue discharge cells, respectively, to perform color display.

  Such a PDP is capable of high-speed display compared to a liquid crystal panel, has a wide viewing angle, is easy to increase in size, and is self-luminous, so that the display quality is high. Recently, it has attracted particular attention among panel displays, and is used for various purposes as a display device at a place where many people gather or a display device for enjoying a large screen image at home.

  By the way, in PDP, in order to avoid that the side exposed to the discharge space of the substrate is exposed to the discharge and the surface state is changed due to sputtering by ion bombardment, a protective film made of, for example, MgO material is formed on the discharge space side of the substrate. In forming the protective film, a method of forming a film by an electron beam evaporation method using single crystal MgO as an evaporation material (film formation material) is employed.

  Here, as an electron beam evaporation apparatus used for the film formation, a film forming material is applied by irradiating an electron beam onto a sublimable film forming material (deposition material) housed in a hearth provided in a film forming chamber. It is performed by evaporating and evaporating the evaporated gas on a substrate moved by a carrier.

The supply of the film forming material to the hearth is performed by rolling the pellet of the film forming material on the shooter and feeding it into the hearth using a material supply path (shooter) (see Patent Document 1).
JP 2008-19473 A

  In the above-described configuration, the shooter serves as a “guide” for putting the pellets of the film forming material into the hearth.

  That is, the film forming material is thrown into the hearth by rolling on the shooter or sliding down.

  Here, in order to form a stable protective film, it is required that the film forming material is stably input to the hearth, that is, the film forming material can pass through the shooter without stagnation and reach the hearth. It becomes important.

  However, conventionally, the film forming material stays in the shooter without rolling and becomes clogged, and the “flow” becomes worse and the supply to the hearth becomes unstable, resulting in the formation of a good protective film. There was a case where the problem of becoming difficult occurred.

  The present invention has been made in view of such a current situation, and an object of the present invention is to provide a film forming material that enables the formation of a good protective layer and hence the realization of a PDP that performs good image display.

  In order to achieve the above object, the film forming material of the present invention is a film forming material that is supplied to the film forming apparatus through the shooter, and the shape thereof is a ratio of the diameter (φ) to the thickness (t) ( (t / φ) is a columnar shape of 0.5 or more.

  ADVANTAGE OF THE INVENTION According to this invention, the film-forming material which enables formation of a favorable protective layer and enables realization of PDP which performs a favorable image display can be provided.

  Hereinafter, although the film-forming material (vapor deposition material) by one Embodiment of this invention is demonstrated using figures, the embodiment of this invention is not limited to this.

  First, the structure of the PDP will be described with reference to FIG. As shown in FIG. 1, in the PDP 100, a front panel 102 made of a front glass substrate 103 and the like and a back panel 110 made of a back glass substrate 111 and the like are arranged to face each other, and the outer peripheral portion thereof is sealed with glass frit or the like. The member is hermetically sealed. A discharge gas such as neon (Ne) and xenon (Xe) is sealed in the discharge space 116 inside the sealed PDP 100.

  On one main surface of the front glass substrate 103 of the front panel 102, a plurality of rows of display electrodes 106 and light-shielding layers (black stripes) 107 made up of scanning electrodes 104 and sustain electrodes 105 are arranged in parallel with each other. ing. Further, a dielectric layer 108 is formed so as to cover the display electrode 106 and the light shielding layer 107, and a protective film 109 made of a metal oxide film such as magnesium oxide (MgO) is formed on the surface thereof.

  In addition, a plurality of stripe-shaped address electrodes 112 are arranged in parallel to each other on one main surface of the back glass substrate 111 of the back panel 110 in a direction intersecting with the scan electrodes 104 and the sustain electrodes 105. The body layer 113 is covered. Further, a partition wall 114 having a predetermined height is formed on the base dielectric layer 113 between the address electrodes 112 to divide the discharge space 116. A phosphor layer 115 that emits red, green, and blue light by ultraviolet rays is sequentially applied to the grooves between the barrier ribs 114 for each address electrode 112. A discharge cell is formed at a position where the scan electrode 104 and the sustain electrode 105 intersect with the address electrode 112, and the discharge cell having the red, green, and blue phosphor layers 115 arranged in the direction of the display electrode 106 is used for color display. It becomes the pixel of.

  Next, a film forming apparatus for forming the protective film 109 will be described. FIG. 2 is a cross-sectional view showing a schematic configuration of a protective film forming apparatus.

  The film forming apparatus 200 is an electron beam (EB) vapor deposition apparatus that heats, melts and deposits a film forming material 202, which is a kind of vacuum film forming method, with an electron beam. In the film forming apparatus 200, a metal hearth 203 filled with pellets such as MgO as a film forming material 202 is disposed inside a vacuum chamber 201 that is a vacuum tank. An electron beam source 204 is installed on the side wall of the vacuum chamber 201, and the film forming material 202 in the hearth 203 is irradiated with the electron beam 204 a from the electron beam source 204. The irradiation position of the electron beam 204 a can be controlled by controlling an electromagnet by a magnetic circuit (not shown) arranged on the side of the hearth 203.

  In addition, a front panel 102 in which a scan electrode 104, a sustain electrode 105, and a dielectric layer 108 are formed is installed substantially above the metal hearth 203 in the vacuum chamber 201, and further above the front panel 102. The heater 205 is installed, and before the film formation on the front panel 102 is performed, the heater 205 is energized to increase the temperature of the front panel 102.

  Here, a shutter plate 206 is provided between the front panel 102 and the hearth 203 to prevent the vapor deposition particles from inadvertently adhering to the front panel 102 at a timing other than the vapor deposition time. The film thickness of MgO deposited on the front panel 102 is managed by the film thickness monitor 207.

  Further, an exhaust pump 208 that performs evacuation, a vacuum gauge 209 that measures a degree of vacuum, and the like are connected to the vacuum chamber 201.

  In addition, since the pellet which is the film forming material 202 in the hearth 203 is consumed by heating and evaporation accompanying the film formation, the pellet is provided with a material supply system for supplying the film forming material 202. The material supply system includes, for example, a material supply chamber 210 that is a sealed container for managing the film forming material 202, a material container 211, and a material supply path (shooter) 212 that guides the film forming material 202 to the hearth 203.

  The material supply chamber 210 and the vacuum chamber 201 are connected via an opening / closing valve 213, and the opening / closing valve 213 is opened only when the film forming material 202 is supplied. Note that the shooter 212 is installed on the side facing the electron beam source 204 so as not to interfere with the electron beam 204 a, and the film forming material 202 is supplied onto the hearth 203.

  Then, the front panel 102 is irradiated with an electron beam 204a on a film forming material 202 which is a film forming material accommodated in the hearth 203 to evaporate the film forming material 202, and the evaporated gas is used as a dielectric of the front panel 102. A protective film 109 is formed by vapor deposition on the layer 108.

  Here, the shape of the shooter 212 is, for example, as shown in FIG. FIG. 3 is a perspective view schematically showing the shooter 212 and the hearth 203.

  FIG. 4 is a perspective view schematically showing a film forming material according to an embodiment of the present invention. As shown in FIG. 4, a film forming material 202 according to an embodiment of the present invention is a film forming material that is supplied to the film forming apparatus 200 (FIG. 2) through a shooter 212 (FIGS. 2 and 3). The shape is a cylindrical shape having a ratio (t / φ) of diameter (φ) to thickness (t) of 0.5 or more.

  That is, conventionally, as schematically shown in a plan view in FIG. 5, columnar / disk-shaped pellets such as MgO as the film forming material 202 form a so-called “bridge” in the shooter 212, and as a result, There is a case in which the clogging causes the supply of the film forming material to the hearth to stagnate and the protective film cannot be stably formed.

  Here, an experiment conducted by the present inventors will be described with reference to FIG. FIG. 6 is a diagram schematically showing the state of the experiment. The inclination angle θ of the shooter 212 is changed in increments of 10 degrees between 20 degrees and 60 degrees, and the film forming material 202 is changed at each inclination angle. The supply amount of the same level as the normal film formation condition was charged into the hearth 203 through the shooter 212, and the occurrence of clogging at that time was confirmed. As the film forming material 202, a material in which the ratio (t / φ) between the diameter (φ) and the thickness (t) of the pellet of the cylindrical film forming material was changed.

  The results are shown in FIG. In FIG. 7, the notation “x” indicates that clogging has occurred, and the notation “◯” indicates that clogging has not occurred. Since the film-forming material supplied to the shooter has a cylindrical shape, (1) rolls on the shooter and falls to the hearth (rolls down), (2) touches the shooter on the bottom or top surface, and slides on the shooter. Things that fall down to Hearth (slides down), and (3) Touch the bottom or top surface of the shooter, slide on the shooter, stop halfway, and don't fall down to Hearth (throw up on the shooter) )), Three forms existed. And when the thing of the said (3) state is piled up, it turned out that a "bridge" generate | occur | produces with a certain signature, As a result, the situation where the film-forming material will be blocked in a shooter will generate | occur | produce.

  In addition, as shown in FIG. 7, the ratio of the film forming material diameter (φ) to the thickness (t) (t / If “φ” is 0.5 or more, “clogging” does not occur. Therefore, it is possible to stably feed the film-forming material into the hearth, so that a good protective film can be formed. I understand.

  This is because the ratio (t / φ) of the diameter (φ) to the thickness (t) of the cylindrical film-forming material is 0.5 or more, and the majority of the film-forming material is a shooter on the cylindrical surface. This is because the above-described form (1) is obtained in which the shooter rolls on the shooter and falls into the hearth while in contact.

  As described above, the present invention is useful for providing a large-screen, high-definition PDP.

Cross-sectional perspective view showing the main part of the plasma display panel Sectional drawing which shows schematic structure of the film-forming apparatus of the protective film of a plasma display panel The perspective view which shows roughly the shape of the shooter in the film-forming apparatus of a protective film The perspective view which shows roughly the film forming material by one embodiment of this invention Plan view schematically showing the clogged state of film forming material in the shooter The figure which shows roughly the state of the experiment which the present inventors conducted The figure which shows the result of the experiment which the present inventors conducted

Explanation of symbols

201 Vacuum chamber 202 Pellet (film forming material)
203 Metal Hearth 204 Electron Beam Source 212 Shooter (Material Supply Path)

Claims (2)

The film forming material is supplied to the film forming apparatus through a shooter, and the shape thereof is a cylindrical shape having a ratio (t / φ) of a diameter (φ) to a thickness (t) of 0.5 or more. Film forming material. The film forming material according to claim 1, wherein the film forming material is a sintered pellet of polycrystalline MgO.

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