JP2008084778A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an image display device capable of maintaining high display performance for a long time and realizing reduction in the manufacturing cost. <P>SOLUTION: This method is for manufacturing an image display device that has housing 10 that has a front substrate 11, provided with a display screen and a rear substrate 12 that is arranged opposed to the front substrate and has electron sources installed, and a getter of non-evaporation type installed in the housing. The housing is heated to a temperature higher than that of activation temperature of the non-evaporation type getter, and the interior of the housing is degassed; while being degassed, the interior of the housing is evacuated; and after the degassing, the housing is maintained at a temperature lower than that of degassing time, and the non-evaporation type getter is activated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image display device having a phosphor screen and an electron source and provided with a getter inside.

  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 large number of electron-emitting devices are provided on the inner surface of the rear substrate as electron emission sources for exciting 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 10 kV, for example, is applied as an anode voltage 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. In order to obtain good getter characteristics, getter material is deposited on the inner surface of the front substrate or the rear substrate or other structures in a vacuum processing apparatus, and both substrates are sealed in a vacuum. A manufacturing method and a manufacturing apparatus of an image display device that forms the image 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. Further, since a drive mechanism for getter vapor deposition must be provided in the vacuum processing apparatus, the reliability and maintainability of the apparatus are deteriorated. 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. For this reason, the gas pressure in the central portion of the vacuum envelope increases, and the electron source element in the central portion of the display device deteriorates, and good characteristics cannot be obtained. Furthermore, if the substrate is heated while a large panel is exhausted from an exhaust pipe or exhaust hole with a small conductance, the pressure inside the envelope is increased by the released gas, and sufficient getter characteristics are obtained. It becomes difficult to activate the getter until it is obtained.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a method for manufacturing an image display device that can maintain good display performance over a long period of time and can reduce manufacturing costs. It is in.

An image display device manufacturing method according to an aspect of the present invention includes an envelope having a front substrate provided with a display surface, a rear substrate disposed opposite to the front substrate and provided with an electron source, and the outer A non-evaporable getter provided in an envelope, and a manufacturing method of an image display device comprising:
Heating the envelope at a temperature higher than the activation temperature of the non-evaporable getter, degassing the envelope, evacuating the envelope while degassing, After the degassing, the non-evaporable getter is activated in a state where the envelope is maintained at a temperature lower than the temperature at the time of degassing.

  According to the aspect of the present invention, the non-evaporable getter disposed in the effective surface of the large panel can be sufficiently activated, high display performance can be maintained for a long time, and the manufacturing cost can be reduced. It is possible to provide a method for manufacturing an image display device that can be used.

Hereinafter, an embodiment in which an image display device of the present invention is applied to an SED will be described in detail with reference to the drawings.
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 whose 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 bonds these substrates together. 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, and the phosphor layers of the same color are in the second direction orthogonal to the first direction. Are arranged with a gap in between. 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.

  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 non-evaporable getter film 23 is formed so as to overlap the light shielding layer 20 of the phosphor screen 16 and, here, to the dividing layer 31. The getter film 23 is disposed on the phosphor screen 16 with a predetermined area. That is, the getter film 23 is formed so as to overlap 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 getter film 23 may be provided only in a region that overlaps the light shielding layer 20, but even in a region that overlaps the phosphor layers R, G, and B, a region that does not receive the electron beam from the corresponding electron-emitting device 18 If so, they may be stacked.

  As shown in FIGS. 3 to 5, the getter film 23 includes non-evaporable getter powder 41, non-evaporable getter powders, and adhesive particles 43 for bonding the non-evaporable getter powder to the front substrate. have. As the non-evaporable getter, various types that are generally used can be selected. However, when used for an SED, a type having a relatively low activation temperature is desirable.

  The particle size of the powder 41 is determined by the vacuum characteristics of the device used, such as the ultimate vacuum and the amount of gas released. In this embodiment, the 50% diameter is 1 to 10 μm, preferably 1 to 5 μm. If the particle size is larger than this, the specific surface area of the non-evaporable getter powder becomes small. Therefore, the gas adsorption speed of the getter is reduced, and it becomes difficult to maintain the inside of the SED envelope 10 at a high degree of vacuum. If the particle diameter is smaller than this, the getter powder 41 becomes very active even at room temperature, and handling becomes difficult.

  Various kinds of adhesive particles 43 that are generally used can be selected, but adhesive particles having a particle diameter smaller than that of the non-evaporable getter powder 41 are used. When the particle size of the adhesive particles 43 is equal to or larger than the particle size of the non-evaporable getter powder 41, most of the powder surface of the non-evaporable getter is shaded by the adhesive particles 43, and the gas Molecules are less likely to be adsorbed on the getter powder. As a result, the adsorption speed of the getter decreases, and the inside of the SED envelope cannot be maintained at a high degree of vacuum.

  Desirable adhesive particles 43 include silver powder having a 50% diameter of 0.1 to 1 μm. The silver powder 41 adheres the non-evaporable getter powder 41 to each other, and simultaneously bonds the non-evaporable getter powder and the front substrate to each other, thereby forming the getter film 23 on the phosphor screen 16. The getter film 23 can be formed by, for example, a screen printing method, a dispensing method, a spray coating method, vapor deposition, or the like.

  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 manufacturing method of SED comprised as mentioned above is demonstrated.
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 line, and forms a plurality of divided regions that are electrically separated from each other.

  A low-melting glass 25 is applied in a rectangular frame shape along the outer periphery of the inner surface of the front substrate 11 to form a sealing layer. Subsequently, the low-melting glass 25 is temporarily fired in the atmosphere to remove the organic solvent and the resin.

  Subsequently, the electron-emitting device 18 and the wiring 21 are formed on the plate glass for the back substrate 12. Next, the low-melting glass 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 made of the low-melting glass 25, the temperature is raised to the crystal precipitation temperature of the low-melting glass 25 in the atmosphere and the temperature is maintained, whereby the side wall 13 is attached to the back substrate 12. Seal. 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.

  The front substrate 11 and the rear substrate 12 formed as described above are aligned with each other and arranged to face each other, and an exhaust line is connected to the exhaust hole 29 of the rear substrate 12. In this state, the front substrate 11 and the back substrate 12 are put into a heating furnace and heated to about 450 ° C. By the heating, melting of the low melting point glass 25 starts. As shown in FIG. 6, for example, the temperature is maintained at about 450 ° C. in an argon atmosphere over 30 minutes, and the low melting point glass 25 is melted and crystal precipitation starts. Thereafter, crystal precipitation of the low melting point glass 25 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. Degassing is performed by releasing undesired gas components adsorbed on the front substrate, rear substrate, phosphor screen, and electron-emitting device. In order to prevent oxidation of the electron-emitting device, it is desirable to make the inside of the heating furnace a non-oxidizing atmosphere.

  During degassing by baking, the exhaust pump is operated to exhaust the inside of the envelope 10 from the exhaust hole 29. 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. In this state, the pressure in the envelope 10 is increased, and this is insufficient to sufficiently activate the non-evaporable getter film 23. If the substrate and the like are sufficiently degassed at 400 to 450 ° C., the pressure in the envelope is reduced by an order of magnitude compared to immediately after the temperature rise.

  Subsequently, the temperature of the heating furnace is lowered to a temperature of 250 ° C. or higher for activating the getter film 23, for example, 350 ° C. Thereby, the pressure in the envelope 10 can be lowered by one digit. Then, the envelope 10 is heated for a predetermined time, for example, 2 hours while being maintained at 350 ° C., and the non-evaporable getter film 23 is activated. As a result, the activated getter film 23 can obtain an adsorption capability capable of sufficiently adsorbing an undesirable gas in the panel.

  After the activation of the non-evaporable 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 configured as described above, the getter film 23 formed of a non-evaporable getter is formed over the entire surface of the phosphor screen 16 and avoids over the phosphor layers R, G, and B. It is formed on the light shielding layer 20. 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.

  According to the SED manufacturing method described above, the degree of vacuum during activation can be improved, and the non-evaporable getter is efficiently activated even when a large display device is evacuated from the exhaust pipe or the exhaust hole. be able to. In addition, it is not necessary to use an expensive vacuum processing apparatus when forming the getter film, an increase in manufacturing cost can be suppressed, and the reliability and maintainability of the apparatus are also improved. As described above, it is possible to obtain an image display device manufacturing method capable of maintaining good display performance over a long period of time and reducing 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 of the member to be the getter film. However, the present invention is not limited to this, and the FED and PDP are not limited thereto. The present invention can also be applied to other devices such as other vacuum apparatuses, fluorescent display tubes, and semiconductor sensors. The material of the non-evaporable getter powder and the adhesive particles is not limited to the above embodiment, and various materials can be used in accordance with the vacuum characteristics, emission gas characteristics, heat resistance, etc. of the device used.

  As the getter, a metal material, an organic material, an inorganic material, or the like can be selected. For example, a metal such as Ti, Zr, V, Fe, Al, Cr, Nb, Ta, W, Mo, Ni, Mn, Y, or an alloy thereof may be used as the non-evaporable getter. The getter is not limited to the front substrate, and may be formed on another constituent member located in the envelope.

  As the material for the adhesive particles, phosphoric acid-based frit glass may be used. Various organic materials can be used for pasting non-evaporable getter powders, such as ethyl acetate, butyl acetate, nitrocellulose, elbasite, and polyethylene carbonate, according to the characteristics of the device used and non-evaporable getter materials. Various types may be selected and used as appropriate. In addition, the mixing ratio of pasting, the forming method of the paste, the firing conditions for forming the getter film, and the like can be variously changed as long as the activated non-evaporable getter can exhibit sufficient gas adsorption performance.

  Needless to say, it is possible to select a suitable shape, size, arrangement, or material of the structure constituting the SED. Various formation dimensions, shapes, arrangements, and film thicknesses of the getter film can be used in accordance with the vacuum characteristics, emission gas characteristics, heat resistance, etc. of the device to be used.

  Regarding the sealing of the front substrate and the rear substrate, an in-line continuous furnace or a batch-type atmospheric firing furnace may be used, or the sealing may be performed in a vacuum. As the electron-emitting device, a pn-type cold cathode device or a field-emission type electron-emitting device may be used.

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 sectional view showing a non-evaporable getter film of the SED. FIG. 6 is a diagram showing a change in heating temperature in the manufacturing process of the SED.

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 ... Non-evaporable getter film, 41 ... Getter powder, 43 ... Adhesive particles

Claims (5)

An envelope having a front substrate provided with a display surface and a rear substrate disposed opposite to the front substrate and provided with an electron source; a non-evaporable getter provided in the envelope; In a method for manufacturing an image display device comprising:
Heating the envelope at a temperature higher than the activation temperature of the non-evaporable getter to degas the envelope;
While degassing, the inside of the envelope is evacuated,
After the degassing, an image display device manufacturing method for activating the non-evaporable getter in a state where the envelope is maintained at a temperature lower than the temperature at the time of degassing.   The method for manufacturing an image display device according to claim 1, wherein the non-evaporable getter is activated at 250 ° C. or higher.   The phosphor screen having a plurality of phosphor layers and a light shielding layer positioned between the phosphor layers is formed on the front substrate, and the non-evaporable getter is formed on the light shielding layer. Manufacturing method of the image display apparatus.   The one or more kinds of metals or alloys of Ti, Zr, V, Fe, Al, Cr, Nb, Ta, W, Mo, Ni, Mn, and Y are used as the non-evaporable getter. Manufacturing method of image display apparatus.   The method for manufacturing an image display device according to claim 1, wherein the inside of the envelope is evacuated through an exhaust hole formed in the envelope.

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