JP2004031276A - Manufacturing method of 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 period of time by preventing the deterioration of gas adsorption ability of a getter material. <P>SOLUTION: A getter material 42 is heated in a vacuum atmosphere, and the degassing of the getter material is carried out. By using the getter material after degassing, a getter film is formed on a constituent member of an outer case. Then, a front substrate and a rear substrate are sealed with each other, and the outer case is formed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing an image display device, and more particularly, to a method for manufacturing an image display device including a front substrate and a rear substrate that are arranged to face each other.
[0002]
[Prior art]
2. Description of the Related Art In recent years, various flat-panel image display devices have attracted attention as next-generation lightweight and thin display devices that replace cathode ray tubes (hereinafter, referred to as CRTs). For example, a plasma display (PDP) using light emission of a phosphor due to a discharge phenomenon, and a field emission display (hereinafter, referred to as FED) mainly using electron emission by an electric field are known.
[0003]
These image display devices have, as a basic configuration, a front substrate and a rear substrate that are arranged to face each other at a predetermined interval, and these substrates constitute an envelope by joining peripheral portions of each other. These image display devices enable good image display by maintaining the space between the front substrate, the counter substrate, and the rear substrate, that is, the inside of the envelope at a high degree of vacuum.
[0004]
In order to maintain the inside of the envelope at a high degree of vacuum for a long period of time, a getter material for adsorbing 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 vapor-deposited on the inner surface of the front substrate or the back substrate or other structures in a vacuum processing apparatus, and both substrates are sealed in a vacuum and surrounded. A process for forming a vessel has been proposed.
[0005]
[Problems to be solved by the invention]
When an evaporable getter material is used as such a getter material, the getter material is usually heated and vapor-deposited in a vacuum processing apparatus of about 10 ⁻⁴ Pa or less to form a getter film on the inner surface of the envelope. . At this time, if the pressure in the vacuum processing apparatus is high, the getter material immediately adsorbs the gas and becomes an oxide, a nitride, a carbonate or the like, and the gas adsorbing ability is greatly deteriorated.
[0006]
In the conventional manufacturing process, when the getter material is heated and vapor-deposited, the getter itself and the structural members of the envelope become instantaneously hot and a large amount of gas is released. Therefore, the degree of vacuum in the vacuum processing apparatus is temporarily deteriorated, and the getter material adsorbs a large amount of gas. As a result, the getter material is sealed in the envelope in a state where its gas adsorption ability has been significantly deteriorated.
[0007]
As described above, in the conventional manufacturing method, the gas release from the getter material itself due to the heating at the time of the getter formation is not taken into consideration, and sufficient gas adsorption characteristics by the getter cannot be obtained. Therefore, the degree of vacuum in the envelope constituting the image display device deteriorates in a short time, and it has been difficult to maintain high display performance over a long period of time.
[0008]
The present invention has been made in view of the above points, and an object of the present invention is to provide an image display device capable of preventing deterioration of the gas adsorption ability of a getter material and maintaining high display performance for a long period of time. It is to provide a manufacturing method.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a method of manufacturing an image display device according to an aspect of the present invention is directed to a method of manufacturing an image display device including an envelope having a front substrate and a rear substrate arranged opposite to each other.
Heating the getter material in a vacuum atmosphere to perform degassing of the getter material, and forming a getter film on the constituent members of the envelope using the degassed getter material in a vacuum atmosphere, The front substrate and the rear substrate are sealed with each other to form the envelope.
[0010]
In addition, a method of manufacturing an image display device according to another aspect of the present invention includes an envelope having a front substrate on which an image display surface is formed, and a rear substrate on which a plurality of electron-emitting devices are provided. In a method for manufacturing an image display device,
The getter material was degassed by heating the getter material in a vacuum atmosphere, and a getter film was formed on the front substrate or another component using the degassed getter material in a vacuum atmosphere. Thereafter, the front substrate and the rear substrate are sealed to each other to form the envelope, and the method for manufacturing an image display device is provided.
[0011]
According to the above configuration, by using the getter material subjected to the degassing process, the gas generated at the time of forming the getter film thereafter is reduced to 1/10 or less as compared with the case of using the untreated getter material. Therefore, deterioration of the degree of vacuum in a vacuum atmosphere can be significantly reduced.
[0012]
As a method of heating the getter material, high-frequency heating can be used for general ring-shaped getter materials, and resistance heating by energization can be used for other types of getter materials. In addition, it was confirmed that an effective degassing process can be performed in a shorter time by using these heating methods in combination.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
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 image display device manufactured by the present manufacturing method, an FED provided with a surface conduction electron-emitting device will be described as an example.
[0014]
As shown in FIGS. 1 and 2, the FED includes a front substrate 11 and a rear substrate 12 each made of a rectangular glass plate as an insulating substrate, and these substrates are opposed to each other with a gap of 1 to 2 mm. Have been. The front substrate 11 and the rear substrate 12 are joined to each other via a rectangular frame-shaped side wall 13 to form a flat rectangular vacuum envelope 10 whose inside is maintained in a vacuum state. .
[0015]
A plurality of spacers 14 are provided inside the vacuum envelope 10 to support an atmospheric pressure load applied to the front substrate 11 and the rear substrate 12. As the spacer 14, a plate-shaped or columnar spacer or the like can be used.
[0016]
On the inner surface of the front substrate 11, a phosphor screen 15 having a red, green, and blue phosphor layer 16 and a matrix black light shielding layer 17 is formed as an image display surface. These phosphor layers 16 may be formed in a stripe shape or a dot shape. On the phosphor screen 15, a metal back 20 made of an aluminum film or the like is formed, and further, a getter film 22 is formed on the metal back.
[0017]
On the inner surface of the rear substrate 12, a large number of surface conduction electron-emitting devices 18 each emitting an electron beam are provided as electron sources for exciting the phosphor layer 16 of the phosphor screen 15. These electron-emitting devices 18 are arranged in a plurality of columns and a plurality of rows corresponding to each pixel. Each of the electron-emitting devices 18 includes an electron-emitting portion (not shown), a pair of device electrodes for applying a voltage to the electron-emitting portion, and the like. In addition, on the inner surface of the back substrate 12, a number of wirings 21 for supplying a potential to the electron-emitting devices 18 are provided in a matrix shape, and the ends thereof are led out of the vacuum envelope 10.
[0018]
In such an FED, when displaying an image, an anode voltage is applied to the phosphor screen 15 and the metal back 20, and the electron beam emitted from the electron-emitting device 18 is accelerated by the anode voltage to collide with the phosphor screen. . Thereby, the phosphor layer 16 of the phosphor screen 15 is excited to emit light, and a color image is displayed.
[0019]
Next, a method of manufacturing the FED configured as described above will be described. First, a method of processing a getter material used for forming a getter film will be described.
As shown in FIGS. 2 and 3, the preheating device for degassing the getter material is configured as, for example, a device employing a high-frequency heating method. That is, the pre-heating device heats the vacuum chamber 30 functioning as a vacuum processing tank, the vacuum pump 32 for evacuating the vacuum chamber to a high vacuum of about 10 ⁻⁵ Pa, and the getter material provided in the vacuum chamber. The heating mechanism 34 is provided. Further, an ionization vacuum gauge 36 for measuring the degree of vacuum in the vacuum chamber is connected to the vacuum chamber 30.
[0020]
A stage 40 for holding a getter material is provided in the vacuum chamber 30, and a plurality of ring-shaped evaporable getter materials 42 are mounted on the stage. As the getter material 42, for example, a reactive getter that vacuum-deposits Ba by a thermal reaction between BaAl ₄ powder and Ni powder can be used. The stage 40 is formed of an insulator such as glass, and is designed so as not to apply a high frequency.
[0021]
The heating mechanism 34 includes a plurality of high-frequency coils 44 provided below the stage 40 in the vacuum chamber 30, a high-frequency generator 46 for applying a high frequency to these coils, and a cooling device 48 for cooling the high-frequency coils. ing. The high-frequency coil 44 is formed by winding a copper pipe in a coil shape, and both ends thereof are led out of the vacuum chamber through a vacuum seal portion 45 provided on the wall of the vacuum chamber 30. Each high-frequency coil 44 is connected to a high-frequency generator 46 provided outside the vacuum chamber 30 and a cooling device 48. The cooling device 48 circulates a cooling medium such as pure water, air, or high-pressure gas inside the high-frequency coil 44 to prevent abnormal heating of the coil.
[0022]
When degassing the getter material 42 by the preheating device, first, a plurality of getter materials 42 are placed on the stage 40. Thereafter, the inside of the vacuum chamber 30 is evacuated by the vacuum pump 32 to maintain a high vacuum of about 10 ⁻⁵ Pa. In this state, a high frequency is applied to the high frequency coil 44 from the high frequency generator 46, and a high frequency is applied to the getter material 42 from the high frequency coil via the stage 40. As a result, the getter material 42 is heated, and the adsorbed gas is released from the getter material. At this time, the heating temperature is set to a temperature lower than the evaporation temperature of the getter material 42, for example, 500 ° C., and the heating is performed for about 30 to 60 seconds. The heating temperature is desirably 200 ° C. or higher.
When the high-frequency coil 44 heats the getter member 42 at high frequency, a cooling medium is circulated inside the high-frequency coil 44 by the cooling device 48 to prevent abnormal heating of the coil.
[0023]
The present inventors conducted a degassing experiment on the getter material 42 while adjusting the high-frequency output. The getter material used here started to evaporate when the temperature exceeded 600 ° C. Therefore, in the degassing process, the output of the high-frequency generator 46 was adjusted, and the getter material 42 was heated to 550 ° C., which is lower than the evaporation temperature. At this time, when the gas released from the getter material 42 was measured, most of the gas conventionally measured at the time of getter vapor deposition was detected. From this, it was confirmed that by performing the degassing treatment on the getter material 42 with the pre-heating device, the impurities contained in the getter material could be degassed by about 90% or more.
For example, _{H 2} 0 is 200 ° C. or higher contained in the getter material, CO, CO ₂ by heating the getter material to above 300 ° C., can be degassed.
[0024]
After degassing the getter material 42 as described above, a getter film is formed using the getter material. In this case, a front substrate 11 on which the phosphor screen 15 and the metal back 20 are formed, and a rear substrate 12 on which the wires 21 and the electron-emitting devices 18 are provided are prepared separately. The side wall 13 is previously sealed to the rear substrate 12 with a sealing material such as frit glass.
[0025]
Then, as shown in FIG. 5, the front substrate 11, the rear substrate 12, the side walls 13, the spacers 14, and the one or more getter materials 42 subjected to the degassing process are arranged in a vacuum processing tank 50. At this time, the vacuum processing tank 50 communicates with the vacuum chamber 30 of the preheating device in a vacuum state, and is evacuated to a desired degree of vacuum by a vacuum pump 52 in advance. Then, after the degassing process, the getter material 42 is transferred from the vacuum chamber 30 of the preheating device to the vacuum processing tank 50 without being exposed to the atmosphere.
[0026]
Thereafter, the getter material 42 is heated to a temperature equal to or higher than the evaporation temperature to evaporate, and is vacuum-deposited on the metal back 20 of the front substrate 11. Thus, a getter film 22 is formed. Subsequently, while maintaining the vacuum state, the front substrate 11 and the side wall 13 are sealed using a desired sealing material to form a vacuum envelope. Thereby, an FED is obtained.
[0027]
The vacuum in the vacuum processing tank 50 during the deposition of the getter film is determined by using the getter material that has been degassed in advance as described above and the getter material that has not been degassed (no preheating). Deterioration was compared. As a result, as shown in FIG. 6, when the getter material subjected to the degassing treatment was used, the degree of vacuum in the vacuum processing tank 50 hardly changed during the vapor deposition, and could be maintained at a high value. In contrast, when a getter material that has not been degassed (no preheating) was used, it was confirmed that the degree of vacuum in the vacuum processing tank 50 was deteriorated immediately after the start of vapor deposition.
[0028]
From the above, according to the present embodiment, the getter material is heated in a vacuum atmosphere to perform degassing of the getter material, and the degassed getter material is used to surround the getter material in a vacuum atmosphere. After forming a getter film on the front substrate which is a component of the vessel, the front substrate and the rear substrate are sealed to each other to form a vacuum envelope, thereby preventing the gas adsorbing ability of the getter material from deteriorating. it can. Therefore, it is possible to obtain an FED capable of suppressing deterioration of the electron-emitting device and maintaining high display performance for a long period of time.
[0029]
As shown in FIG. 7, the performance retention of the formed FED is different between the case where the getter material which has been degassed in advance is used and the case where the getter material which has not been degassed (no preheating) is used. Compared. As a result, when the getter material which has been degassed in advance is used, high performance can be maintained for a long period of time without causing initial deterioration of the getter film. Here, the performance retention indicates the rate of change of the emission current value (emission charge amount) of the electron source from the initial characteristics. Although the display luminance of the FED decreases when the retention ratio decreases, it can be seen that according to the present embodiment, the luminance decrease is greatly reduced.
[0030]
The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention. For example, the dimensions, materials, and the like of each component are not limited to the numerical values and materials shown in the above-described embodiment, but can be variously selected as needed. The method of heating the getter material in the degassing process is not limited to the high-frequency heating described above, and resistance heating in which electric current is applied to the getter material to heat it may be used.
[0031]
Further, in the above-described embodiment, the degassing process of the getter material and the film forming process of the getter film are performed in separate vacuum processing tanks. However, the configuration is such that these processes are performed in the same vacuum processing tank. It may be. In this case, immediately after performing the degassing process, the degree of vacuum in the vacuum processing tank temporarily deteriorates. Therefore, it is necessary to sufficiently exhaust the generated gas by a vacuum pump. Therefore, a certain period of time is allowed until the degree of vacuum is restored, and then the above-described film forming process is performed. Although the time varies depending on the configuration of the vacuum processing tank and the performance of the exhaust pump, the apparatus used in the experiment was able to shift to the film forming processing within 5 minutes after the degassing processing.
[0032]
In addition, the getter film may be deposited not only on the front substrate but also on other constituent members located in the vacuum envelope. Further, the present invention is not limited to the FED, but may be applied to the manufacture of other image display devices such as a PDP.
[0033]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide a manufacturing method capable of manufacturing an image display device that can prevent deterioration of the gas adsorption ability of a getter material and maintain high display performance for a long period of time. .
[Brief description of the drawings]
FIG. 1 is a perspective view showing an FED as an example of an image display device.
FIG. 2 is a sectional view of the FED taken along line AA in FIG. 1;
FIG. 3 is a cross-sectional view showing a preheating device used for manufacturing the FED.
FIG. 4 is an enlarged sectional view showing a heating mechanism of the preliminary heating device.
FIG. 5 is a sectional view showing a getter film forming step and a sealing step in the FED.
FIG. 6 is a graph showing a change in the degree of vacuum in a vacuum processing tank in a case where a getter material subjected to degassing is used and a case where a getter material not subjected to degassing is used.
FIG. 7 is a graph showing the performance retention of the manufactured FED in comparison between a case where a degassed getter material is used and a case where a degassed getter material is used.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Vacuum envelope 11 ... Front substrate 12 ... Back substrate 13 ... Side wall 15 ... Phosphor screen 18 ... Electron emission element 20 ... Metal back 22 ... Getter film 30 ... Vacuum chamber 34 ... Heating mechanism 42 ... Getter material 44 ... High frequency Coil 50: vacuum processing tank

Claims (8)

In a method of manufacturing an image display device including an envelope having a front substrate and a rear substrate disposed to face each other,
The getter material is heated in a vacuum atmosphere to degas the getter material,
After forming a getter film on the constituent members of the envelope using the degassed getter material in a vacuum atmosphere, the front substrate and the rear substrate are sealed together to form the envelope. A method for manufacturing an image display device, comprising: In a method for manufacturing an image display device including an envelope having a front substrate on which an image display surface is formed, and a rear substrate on which a plurality of electron-emitting devices are provided,
The getter material is heated in a vacuum atmosphere to degas the getter material,
In a vacuum atmosphere, using the degassed getter material, after forming a getter film on the front substrate or other constituent members, sealing the front substrate and the rear substrate together to form the envelope. A method for manufacturing an image display device, comprising: 3. The method according to claim 1, wherein the getter material is kept in a vacuum atmosphere from the degassing process to the formation of the getter film. 4. The method according to claim 1, wherein a reactive getter is used as at least one of the getter materials. 5. The method according to claim 1, wherein the getter film is formed by vacuum-depositing the getter material in the vacuum atmosphere. The method of manufacturing an image display device according to claim 1, wherein the getter material is heated by high-frequency heating in the degassing process of the getter material. The method according to claim 1, wherein the getter material is heated by resistance heating in the degassing process of the getter material. After the getter material is heated to a temperature lower than the evaporating temperature of the getter material in a vacuum processing tank and degassed, the getter material is heated in the other vacuum processing tank without breaking the vacuum state. The method according to claim 1, wherein the getter film is formed by heating as described above.

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