JP2008091089A - Manufacturing method of image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an image display device capable of maintaining high display performance over a long period of time and capable of reducing a manufacturing cost, and the image display device. <P>SOLUTION: This is the manufacturing method of the image display device equipped with an enclosure having a front face substrate 11 and a rear face substrate arranged opposite to this front face substrate, and non-evaporation type getters installed in the enclosure. Getter films are formed by applying a particulate getter material and a low viscosity solution having a viscosity of 1 to 1,000 mPa.S on the inner face of the constitution member constituting the enclosure by spraying. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of manufacturing an image display device including an envelope having substrates disposed opposite to each other and a getter disposed inside the envelope.

  In recent years, as a lightweight and thin image display device, a liquid crystal display (hereinafter referred to as LCD) that controls the intensity of light using the orientation of liquid crystal, a plasma display panel (hereinafter referred to as LCD) that emits phosphors by ultraviolet rays of plasma discharge. (Referred to as PDP), field emission display (hereinafter referred to as FED) that emits a phosphor with an electron beam of a field emission electron emitter, and surface conduction electron that emits a phosphor with an electron beam of a surface conduction electron emitter. Emission element displays (hereinafter referred to as SEDs) have been developed.

  For example, an FED generally has a front substrate and a rear substrate that are opposed to each other with a predetermined gap, and these substrates are surrounded by a vacuum by surrounding each other through a rectangular frame-shaped side wall. Make up the vessel. A phosphor screen is formed on the inner surface of the front substrate, and a number of electron-emitting devices are provided on the inner surface of the rear substrate as electron emission sources that excite the phosphor to emit light.

  In order to support an atmospheric pressure load applied to the back substrate and the front substrate, a plurality of support members are disposed between these substrates. The potential on the back substrate side is almost the ground potential, and an anode voltage is applied to the phosphor screen. An image is displayed by irradiating the phosphors of red, green, and blue constituting the phosphor screen with the electron beams emitted from the electron-emitting devices and causing the phosphors to emit light.

  In such an FED, it is important to maintain a high degree of vacuum inside the envelope. If the degree of vacuum is low, stable electron emission cannot be performed, and the life of the image display device is reduced. Further, in PDP, it is an important technique to keep the inert gas filling the inside of the envelope with high purity.

In order to maintain a high vacuum in the envelope for a long period of time, a getter material that adsorbs the released gas is provided in the envelope and plays an important role. Conventionally, in order to improve the gas adsorption characteristics of the getter material, the getter material is deposited on the inner surface of the front substrate or the rear substrate or other structure in a vacuum processing apparatus, and both the substrates are sealed in a vacuum. A manufacturing method and a manufacturing apparatus for an image display device forming an envelope have been proposed (see, for example, Patent Document 1). For example, a method of forming a non-evaporable getter layer in a region adjacent to the panel side of the PDP has been proposed (see, for example, Patent Document 2).
JP 2001-229824 A JP-A-11-191378

  In the method of forming a getter film and sealing an envelope in a vacuum processing apparatus, undesired gas molecules are efficiently adsorbed on the getter film. For this reason, the inside of the vacuum envelope of the FED is maintained at a high degree of vacuum over a long period of time.

  However, since this method uses a large vacuum processing apparatus, the manufacturing cost increases, and as a result, the cost of the image display apparatus also increases. When an evaporative getter film is deposited over the entire surface of the phosphor screen, there is a problem in performance that the luminance is lowered.

  In addition, in the method of forming a non-evaporable getter film in the area adjacent to the side of the panel, undesired gas molecules existing in the area away from the getter, that is, in the central part of the phosphor screen are efficiently adsorbed to the getter. Can not do it. Therefore, the gas pressure at the center of the vacuum envelope increases, and the brightness at the center of the display device decreases. Furthermore, if the substrate is heated with the exhaust pipe or exhaust hole having a small conductance being exhausted, the pressure inside the envelope rises due to the released gas, and the getter is removed until sufficient getter characteristics are obtained. It becomes difficult to activate.

  The present invention has been made in view of the above points. The object of the present invention is to easily form a getter, to maintain good display performance over a long period of time, and to reduce the manufacturing cost. An object of the present invention is to provide a method for manufacturing a possible image display device.

  An image display device manufacturing method according to an aspect of the present invention includes a front substrate, an envelope disposed opposite to the front substrate and having a rear substrate, a non-evaporable getter provided in the envelope, In the manufacturing method of the image display apparatus provided with the above, a fine particle getter material and a viscosity of 1 to 1000 mPa.s are formed on the inner surface of the constituent member constituting the envelope. A getter film is formed by applying a low-viscosity solution of S by spraying.

  According to the aspect of the present invention, it is possible to form a getter film uniformly in a short time, and the getter material can function effectively. In addition, it is possible to provide a method for manufacturing an image display device that can maintain high display performance over a long period of time without using an expensive vacuum device and can reduce the manufacturing cost.

Hereinafter, a method for manufacturing an image display device according to an embodiment of the present invention will be described in detail with reference to the drawings. First, as an example of an image display device manufactured by this manufacturing method, an SED including a surface-conduction electron-emitting device will be described.
As shown in FIGS. 1 and 2, the SED includes a front substrate 11 and a rear substrate 12 each made of a rectangular glass plate, and these substrates are arranged to face each other at a predetermined interval. The back substrate 12 is formed with a size larger than that of the front substrate 11. The front substrate 11 and the back substrate 12 constitute a flat envelope 10 whose peripheral portions are joined to each other through a rectangular frame-shaped side wall 13 and the inside is maintained in a vacuum state. The side wall 13 functioning as a bonding member is sealed to the peripheral edge of the front substrate 11 and the peripheral edge of the back substrate 12 by, for example, a sealing material 25 such as low melting glass or low melting metal, and these substrates are bonded to each other. is doing.

  A plurality of plate-like support members 14 are provided inside the envelope 10 in order to support an atmospheric pressure load applied to the front substrate 11 and the rear substrate 12. These support members 14 extend in a direction parallel to one side of the envelope 10 and are arranged at a predetermined interval along a direction orthogonal to the one side. Both ends in the longitudinal direction of each support member 14 are opposed to the side wall 13 with a gap.

  As shown in FIGS. 2 to 4, a phosphor screen 16 that functions as an image display surface is formed on the inner surface of the front substrate 11. The phosphor screen 16 is configured by arranging red, green, and blue phosphor layers R, G, and B, and a black light-shielding layer 20 positioned between the phosphor layers. The phosphor layers R, G, and B of three colors of red, green, and blue are formed alternately with a gap in the first direction parallel to the long side of the front substrate 11, and the phosphor layers of the same color are formed. They are arranged with a gap in a second direction orthogonal to the first direction. Each of the phosphor layers R, G, and B constitutes a subpixel with single colors of red, green, and blue, and constitutes one pixel by combining the subpixels of three colors. The phosphor layer is not limited to a dot shape, and may be formed in a stripe shape.

  A matrix-shaped dividing layer 31 is formed so as to overlap the light shielding layer 20 of the phosphor screen 16. A metal back layer 17 made of an aluminum film or the like is formed on the phosphor screen 16. According to this embodiment, the metal back layer 17 is divided in the vertical direction and the horizontal direction by the dividing layer 31 and has a plurality of divided regions that are electrically separated from each other. The metal back layers 17 that are electrically separated from each other by the dividing layer 31 are positioned so as to overlap the phosphor layers R, G, and B, respectively.

  A plurality of non-evaporable getter films 23 are formed on the light shielding layer 20 of the phosphor screen 16 and, here, on the dividing layer 31, and are arranged with a gap therebetween. The getter film 23 is formed on the dividing layer 31 so as to avoid the phosphor layers R, G, and B, and has a plurality of regions that are electrically separated from each other. The non-evaporable getter film 23 may be provided only in a region overlapping the light shielding layer 20, but even in a region overlapping the phosphor layers R, G, and B, an electron beam from the corresponding electron emitter 18 is used. If the region does not hit, it may be overlapped.

  The getter film 23 adsorbs unnecessary gas in the envelope 10 and maintains a high degree of vacuum in the envelope. As will be described later, each getter film 23 is formed by fixing a non-evaporable getter powder in a film shape on a dividing layer with a material having an adhesive effect.

  As shown in FIG. 2, on the inner surface of the back substrate 12, a number of surface conduction type electron emitters each emitting an electron beam as an electron source for exciting the phosphor layers R, G, B of the phosphor screen 16 are provided. An element 18 is provided. These electron-emitting devices 18 are arranged in a plurality of columns and a plurality of rows corresponding to each pixel. Each electron-emitting device 18 includes an electron emitting portion (not shown) and a pair of device electrodes for applying a voltage to the electron emitting portion. A large number of wirings 21 for supplying a potential to the electron-emitting devices 18 are provided in a matrix on the inner surface of the rear substrate 12, and end portions thereof are drawn out of the envelope 10.

  Exhaust holes 29 for exhausting the inside of the envelope 10 in the exhaust process are formed through the periphery of the back substrate 12, for example, corners. The exhaust hole 29 is provided at a position away from the phosphor screen 16, that is, at a position away from the effective display area. The exhaust hole 29 is hermetically sealed by the lid member 30. The number of exhaust holes 29 is not limited to one, and can be increased as necessary.

  In such an SED, when displaying an image, an anode voltage is applied to the phosphor screen 16 and the metal back layer 17, and the electron beam emitted from the electron-emitting device 18 is accelerated by the anode voltage to the phosphor screen. Collide. Thereby, the phosphor layers R, G, and B of the phosphor screen 16 are excited to emit light, and a color image is displayed.

Next, the configuration of the getter film 23 and the method for manufacturing the SED will be described.
The non-evaporable getter film 23 is formed by spraying and fixing a mixed solution obtained by mixing a non-evaporable getter powder with a low-viscosity solution having an adhesive effect on a phosphor screen. In this embodiment, as a non-evaporable getter material, a mixture containing Zr, V, and Fe is melted by arc melting to produce an ingot, and this ingot is averaged to 10 μm or less, preferably 10 nm by a pulverizer. A non-evaporable getter powder is manufactured by pulverizing to about 10 μm, for example, about 10 μm.

  The getter material is not limited to Zr, V, and Fe, and other metal materials, organic materials, inorganic materials, and the like can be selected. For example, as a non-evaporable getter material, one or more kinds of metals or two or more kinds of alloys among Ti, Zr, V, Fe, Al, Cr, Nb, Ta, W, Mo, Ni, Mn, and Y are used. It may be used. As the solution having low viscosity, colloidal silica, colloidal solution such as colloidal alumina using fine oxide particles, sodium-based water glass, potassium-based water glass, metal alkoxide, or a mixture thereof can be used.

  In the manufacturing process of the SED, first, the phosphor screen 16 is formed on the plate glass to be the front substrate 11. Subsequently, a matrix-shaped dividing layer 31 is formed on the light shielding layer 20 of the phosphor screen 16, and then a metal back layer 17 made of an aluminum film or the like is deposited on the phosphor screen 16 by vapor deposition. The metal back layer 17 is divided in the vertical direction and the horizontal direction by the dividing layer 31 to form a plurality of divided regions that are electrically separated from each other.

  Subsequently, a getter film 23 is formed on the phosphor screen 16. In this case, for example, a zirconium alloy powder having an average particle diameter of 10 μm is prepared as a getter material, and colloidal silica having a viscosity of about 100 mPa · s is prepared as a low viscosity solution. For example, a getter material and a low-viscosity solution are mixed at a ratio of 1: 1 to make a mixed solution. When the proportion of the getter material is large, the adhesive strength with the substrate is lowered, and when the proportion of colloidal silica is large, the formed getter film is cracked.

  Subsequently, as shown in FIG. 5, a plate-shaped metal mask 40 in which a large number of openings 41 are patterned is prepared. The front substrate 11 is placed on the heating plate 42 and the metal mask 40 is placed on the metal back layer 17 and the dividing layer 31. At this time, the metal mask is aligned with the front substrate 11 so that the opening 41 of the metal mask 40 is positioned on the dividing layer 31. If necessary, a magnet 44 is disposed outside the heating plate 42 to attract the metal mask 40 and bring it into intimate contact with the phosphor screen 16 and prevent displacement of the metal mask.

  The front substrate 11 is heated to 40 to 150 ° C., for example, about 80 ° C. by the heating plate 42. In this state, as shown in FIG. 6, the above-mentioned mixed solution is sprayed from the two-fluid spray nozzle 46 onto the front substrate 11 through the metal mask 40, and the entire formation area is scanned. As a result, the mixed solution is attached onto the dividing layer 31 through the opening 41 of the metal mask 40. Then, the adhering mixed solution is heated by the heated front substrate 11, and the low viscosity solution is evaporated and dried. As a result, the getter powder is fixed on the dividing layer 31 and the getter film 23 is patterned.

  By spraying the mixed solution while the front substrate 11 is heated, the low-viscosity solution adhering to the dividing layer 31 is immediately dried to fix the getter powder. Therefore, the patterning accuracy of the getter film 23 is improved. If the substrate temperature is too high, the low-viscosity solution dries immediately before the mixed solution adheres to the dividing layer 31, and the adhesive force with the substrate decreases, or unevenness occurs on the surface of the formed getter layer. When the substrate temperature is low, a low viscosity solution enters between the metal mask 40 and the front substrate when the getter film 23 is stacked, and bleeding occurs. For this reason, the heating temperature of the front substrate 11 is preferably 40 to 150 ° C.

  FIG. 7 shows an enlarged view of the getter film 23 formed of the non-evaporable getter particles 23a and the low-viscosity solution 23b. The film thickness of the non-evaporable getter film 23 was set to about 15 μm. After the getter film 23 is formed, the non-evaporable getter particles 23a are firmly bonded to each other by the colloidal silica that is the low-viscosity solution 23b, and the surface of the non-evaporable getter particles 23a is exposed in a relatively large area. Can do. Therefore, after the non-evaporable getter particles 23a are activated in the subsequent activation step, the gas adsorption function of the non-evaporable getter can be sufficiently exhibited.

The film thickness of the getter film 23 is preferably 5 μm to 50 μm. If it is less than 5 μm, the gas adsorption ability of the getter film tends to be insufficient, and if it exceeds 50 μm, there is a tendency to cause discharge with the back substrate side. The film thickness of the getter film 23 can be adjusted by spraying the mixed solution a plurality of times and applying it repeatedly.
Thereafter, as shown in FIG. 7, the metal mask 40 is removed from the front substrate 11. As a result, a getter film 23 having a predetermined pattern is formed as shown in FIGS.

  On the other hand, the electron-emitting device 18 and the wiring 21 are formed on the plate glass for the back substrate 12. Next, low melting point glass as the sealing material 25 is applied in a rectangular frame shape along the inner periphery of the back substrate 12 to form a sealing layer. The back substrate 12 is temporarily fired in the atmosphere. Then, after aligning the side wall 13 on the sealing layer, the temperature is raised to the crystal precipitation temperature of the low-melting glass in the atmosphere, and the side wall 13 is sealed to the back substrate 12 by maintaining the temperature. Thereafter, the electron-emitting device 18 is activated. Next, the plurality of support members 14 are aligned with respect to the back substrate 12, and the end portions thereof are fixed to the back substrate.

  Subsequently, the peripheral portions of the front substrate 11 and the back substrate 12 formed as described above are sealed. In the present embodiment, the front substrate 11 and the rear substrate 12 are aligned with each other, and placed in a heating furnace (not shown) in a state of being opposed to each other with a certain gap. Then, the front substrate 11 and the back substrate 12 are heated to about 450 ° C. By heating, melting of the low melting point glass previously applied starts. For example, the temperature is maintained at about 450 ° C. in an argon atmosphere over 30 minutes, and the low melting glass melts and crystal precipitation begins. Thereafter, crystal precipitation of the low melting point glass is almost completed, and the back substrate 12 and the front substrate 11 are sealed to each other through the side wall 13 by the low melting point glass.

  Subsequently, the temperature in the heating furnace is maintained at a high temperature higher than the activation temperature of the getter film, for example, 400 to 450 ° C., and the front substrate 11 and the back substrate 12 are baked for about 1 hour. As a result, undesired gas components adsorbed on the front substrate, the rear substrate, the phosphor screen, and the electron-emitting device are released to perform degassing. In order to prevent oxidation of the electron-emitting device, it is desirable to seal and bake the inside of the heating furnace in an inert atmosphere and a reducing atmosphere. The atmosphere can be selected according to time and temperature.

  During the degassing by baking, the inside of the envelope 10 is exhausted from the exhaust hole 29 by the exhaust pump. As a result, gas components desorbed from the substrate, the phosphor screen, and the like are discharged from the envelope 10 to the outside, and the inside of the envelope 10 is in a clean vacuum state.

  The getter film 23 is activated by heating the front substrate 11 and the back substrate 12 at about 350 to 500 ° C. for a predetermined time, for example, 2 hours. As a result, the getter film 23 is in an operating state without substantially deteriorating the adsorption capability.

  After the activation of the getter film 23 is completed, the envelope 10 is cooled to a desired temperature, and the exhaust hole 29 of the envelope 10 is hermetically sealed by the lid member 30. The lid member 30 can be sealed using a known technique such as sealing with a low melting point metal such as indium or welding by local heating. Next, the envelope 10 is removed from the heating furnace. The SED envelope 10 is completed through the above steps.

  According to the SED and the manufacturing method configured as described above, the getter film is formed on the entire surface of the phosphor screen 16 and is formed on the light shielding layer 20 so as to avoid the phosphor layers R, G, and B. Has been. For this reason, the entire interior of the envelope 10 can be maintained at a high degree of vacuum without lowering the luminance by the getter film 23.

  By mixing and spraying a getter material and a low-viscosity solution, it becomes possible to form a getter film uniformly in a short time, making the getter material function effectively, and providing good display performance over a long period of time. Can be maintained. Without using an expensive vacuum device, it is possible to provide a method for manufacturing an image display device that can maintain high display performance over a long period of time and can reduce the manufacturing cost.

  The present invention is not limited to the above-described embodiment, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. Some constituent elements may be deleted from all the constituent elements shown in the embodiments, or constituent elements over different embodiments may be appropriately combined.

  In the above-described embodiment, the SED provided with the front substrate having the phosphor screen on the inner surface has been described as an example. However, the present invention is not limited to this and is applied to other display devices such as an FED and a PDP. You can also. The dimensions, materials, and the like of each component are not limited to the numerical values and materials exemplified in the above-described embodiment, and can be variously selected as necessary.

  The material of the getter material and the low-viscosity solution is not limited to the above-described embodiment, and various materials can be selected according to the vacuum characteristics, emission gas characteristics, heat resistance, and the like of the device to be used. For example, as the getter material, metal materials other than those described above, organic materials, inorganic materials, and the like can be selected. The spray method is not limited to the two-fluid method, and any one-fluid method, electrostatic spray, or any other device that can spray liquid can be used.

  In the above-described embodiment, the getter film is provided on the phosphor screen. However, the present invention is not limited to this, and the getter film may be formed on another constituent member constituting the envelope. For example, a getter film may be provided on the structure on the back substrate 12 side, and in this case, the wiring 21 may be formed at a position where the wiring 21 is not short-circuited at a position away from the electron-emitting device 18.

FIG. 1 is a perspective view showing a partially broken SED according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the SED along line AA in FIG. FIG. 3 is an enlarged plan view showing a part of the front substrate and phosphor screen of the SED. 4 is a cross-sectional view of the front substrate along the line BB in FIG. 3. FIG. 5 is a cross-sectional view showing a state where a front substrate is placed on a heating plate and a metal mask is placed on a phosphor screen in the SED manufacturing process. FIG. 6 is a cross-sectional view showing a state in which a non-evaporable getter powder and a low-viscosity solution are sprayed on a phosphor screen through a metal mask in the SED manufacturing process. FIG. 7 is an enlarged cross-sectional view of a non-evaporable getter film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Envelope, 11 ... Front substrate, 12 ... Back substrate, 13 ... Side wall,
14 ... support member, 16 ... phosphor screen, 17 ... metal back layer,
18 ... electron-emitting device, R, G, B ... phosphor layer, 20 ... light shielding layer,
23 ... Getter film, 23a ... Getter powder, 23b ... Low viscosity solution,
40 ... Metal mask 46 ... Spray nozzle

Claims (8)

In a manufacturing method of an image display device comprising: a front substrate, an envelope having a rear substrate disposed opposite to the front substrate, and a non-evaporable getter provided in the envelope.
Fine particles of getter material and a viscosity of 1-1000 mPa. A method for manufacturing an image display device, wherein a getter film is formed by applying a low viscosity solution of S by spraying.   The method for manufacturing an image display device according to claim 1, wherein the getter material and a low viscosity solution are mixed and the mixed solution is sprayed.   The manufacturing method of the image display apparatus of Claim 1 or 2 which sprays the said fine particle getter material and a low-viscosity solution in the state which heated the said structural member at 40-150 degreeC.   The method for manufacturing an image display device according to claim 1, wherein a mask having a predetermined aperture pattern is disposed on the component member, and the getter material and the low-viscosity solution are sprayed through the mask.   2. The method for manufacturing an image display device according to claim 1, wherein a getter material having a particle diameter of 10 nm to 10 [mu] m is used.   The said getter material uses Ti, Zr, V, Fe, Al, Cr, Nb, Ta, W, Mo, Ni, Mn, Y, or one or more types of metals or two or more types of alloys. Manufacturing method of the image display apparatus.   A phosphor screen having a plurality of phosphor layers and a light shielding layer located between the phosphor layers is formed on the inner surface of the front substrate, and the getter material and a low viscosity solution are sprayed on the light shielding layer to form a getter film. The manufacturing method of the image display apparatus of Claim 1. After forming the getter layer, sealing the peripheral portions of the front substrate and the back substrate,
Heating the envelope at a temperature higher than the activation temperature of the getter film to degas the envelope;
While degassing, the inside of the envelope is evacuated,
The method for manufacturing an image display device according to claim 7, wherein the non-evaporable getter is activated after the degassing.

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