JP2004349009A - Method of manufacturing image display device, apparatus for manufacture, and image display device manufactured by this method of manufacture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an image display device preventing drop in gas adsorbing capacity of a getter material and holding high display performance for a long time, and to provide an apparatus of manufacture and an image display device. <P>SOLUTION: The method of manufacturing the image display device contains a getter process forming a getter film on a display surface of a front substrate 11, and a sealing process constituting an envelope by sealing peripheral parts of the front substrate formed with the getter film and a rear substrate, the getter process is conducted in such a state that the temperature of the display surface is controlled at 200 °C or less, and after the getter process, the temperature of the display surface is kept at 200 °C or less. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for manufacturing an image display device, and more particularly to an image display device having a front substrate and a rear substrate that are arranged to face each other, and an image display device manufactured by the manufacturing method.
[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. In particular, the FED enables good image display by maintaining the space between the front substrate and the rear substrate, that is, the inside of the envelope at a high degree of vacuum. Also, in PDP, it is an important technique to keep the inert gas filling the inside of the envelope at high purity.
[0004]
In order to maintain a high vacuum inside the envelope for a long period of time, a getter material for adsorbing the released gas is provided in the envelope and plays an important role. Conventionally, after baking out the components of the envelope at a high temperature under a vacuum atmosphere (hereinafter, referred to as a baking step) and sufficiently degassing, a getter material is placed in a vacuum processing apparatus on the inner surface of a front substrate or a rear substrate, Alternatively, a method of manufacturing an image display device is performed in which vapor deposition is performed on another structure (hereinafter, referred to as a getter process), and both substrates are sealed in a vacuum to form an envelope (hereinafter, referred to as a sealing process). And a manufacturing apparatus have been proposed (for example, Patent Document 1).
[0005]
According to the above manufacturing method, the baking step is performed when the components of the envelope are heated to a temperature of at least 200 ° C., generally about 300 ° C. to 400 ° C., in order to obtain a sufficient degassing effect. There are many. After the baking process, both substrates and other components move to the getter process, and the getter film is formed while being kept at a high temperature. This is because the components need to be heated again in the next sealing step and the time required for cooling is shortened to increase the production efficiency, as described later.
[0006]
In the sealing step, the substrate is heated again to seal the peripheral portion. When general frit glass is used as the sealing material, the sealing portion is heated to a high temperature exceeding 350 ° C., which is the melting temperature of the frit glass. In such a sealing step, a method of heating the entire surface of the substrate substantially uniformly (hereinafter, uniform heating sealing) and a method of locally heating only the sealing portion (hereinafter, local heating method) have been proposed. . However, even in the case of the local heating method, it is technically difficult to keep the entire image display area of the substrate at a certain temperature or lower.
[0007]
[Patent Document 1]
JP 2001-229824 A
[Problems to be solved by the invention]
As described above, in the conventional manufacturing method, the getter step is located between the baking step and the sealing step that require heating at a high temperature, so that the substrate is kept at a high temperature. It has been implemented. However, when a getter is formed on a high-temperature member, the adsorption capability of the getter film is greatly impaired. In the case of barium, which is a general getter material, when a getter film is formed in a state where the substrate is heated to 200 ° C. or higher, the adsorption capacity is 1/5 of that when the film is formed at room temperature of 25 ° C. It falls to below.
[0009]
Further, even when the substrate is cooled once after the baking step and barium is formed at a temperature of 200 ° C. or less, the substrate on which the getter film is formed is heated to 200 ° C. or more in the subsequent sealing step. Similarly, the adsorption ability of the getter film is reduced. Therefore, the degree of vacuum and gas purity in the envelope constituting the image display device deteriorate in a short time, and it becomes difficult to maintain high display performance for a long period of time.
[0010]
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 a decrease in gas adsorption capacity of a getter material and maintaining a high display performance for a long period of time. An object of the present invention is to provide a method and an apparatus for manufacturing an image display device, and an image display device formed by the manufacturing method.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a method for manufacturing an image display device according to an aspect of the present invention is directed to an image display device including an envelope having a front substrate provided with a display surface and a rear substrate disposed opposite to the front substrate. In a method for manufacturing an apparatus,
A getter step of forming a getter film overlying the display surface, and a sealing step of forming an envelope by sealing a peripheral portion of the back substrate and the front substrate on which the getter film is formed, The getter step is performed in a state where the temperature of the display surface is adjusted to 200 ° C. or lower, and the temperature of the display surface is maintained at 200 ° C. or lower after the getter step.
[0012]
According to another aspect of the present invention, there is provided an apparatus for manufacturing an image display device, comprising: a front substrate provided with a display surface; and an envelope having a back substrate disposed opposite to the front substrate. In the device,
A getter forming apparatus having a temperature adjustment mechanism for adjusting the temperature of the display surface, forming a getter film on the display surface in a state where the temperature of the display surface is adjusted to 200 ° C. or less, and a temperature of the display surface And a sealing device for sealing the peripheral portions of the rear substrate and the front substrate on which the getter film is formed, while maintaining the temperature at 200 ° C. or less.
[0013]
According to the manufacturing method and the manufacturing apparatus configured as described above, the gas adsorption capacity of the getter material is maintained by keeping the display surface of the front substrate as the getter formation region at 200 ° C. or less from the getter formation to the sealing. Deterioration can be prevented. As a result, it is possible to obtain an FED capable of maintaining a high degree of vacuum in the envelope and maintaining high display performance for a long period of time.
[0014]
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.
[0015]
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. .
[0016]
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.
[0017]
On the inner surface of the front substrate 11, a phosphor screen 15 having red, green, and blue phosphor layers 16 and a matrix-shaped 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.
[0018]
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.
[0019]
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.
[0020]
Next, a method of manufacturing the FED configured as described above will be described.
[0021]
First, as shown in FIG. 3, a front substrate 11 having an inner surface on which a phosphor screen 15 and a metal back 20 are formed, and a rear substrate 12 provided with an electron-emitting device 18 are prepared. In addition, the side wall 13 and the plurality of spacers 14 are bonded on the back substrate 12 in advance. Further, for example, a sealing material is filled along the entire periphery of the upper surface of the side wall 13. Here, indium was used as a sealing material. The front substrate 11, the rear substrate 12, and the above-described respective components constituting the outer vacuum container 10 are put into the baking chamber 30. The side walls 13 and the spacers 14 may be joined in a later step, or may be joined to the front substrate 11, as the case may be.
[0022]
The baking chamber 30 is maintained at a degree of vacuum of about 10 ⁻⁴ Pa by the exhaust pump 31. Inside the baking chamber 30, a heating mechanism 32 having hot plates 32a and 32b is provided. In the baking chamber 30, the front substrate 11 and the rear substrate 12 are arranged with their inner surfaces facing each other with a gap. The hot plates 32a and 32b are disposed so as to face the outer surfaces of the front substrate 11 and the rear substrate 12, respectively. As the heating mechanism 32, a heating mechanism such as a lamp system, a sheath heater system, or an electron beam irradiation (EB) heating system may be employed.
[0023]
Subsequently, the front substrate 11, the rear substrate 12, and other components of the envelope 10 are subjected to heat treatment by the hot plates 32a and 32b in the vacuum atmosphere of the baking chamber 30, and gas is released from each component. Baking process). Here, each component was uniformly heated to 350 ° C. over 30 minutes and held for 30 minutes. The released gas generated in the baking step is quickly exhausted by the exhaust pump 31 to maintain the baking chamber 30 at a degree of vacuum of 10 ⁻⁴ Pa.
[0024]
Next, the front substrate 11 is taken out of the baking chamber 30, and is put into the getter chamber 40 without breaking the vacuum state as shown in FIG. The getter chamber 40 is maintained at a degree of vacuum of about 10 ⁻⁵ Pa by an exhaust pump 44. In the getter chamber 40, a panel heater 41 functioning as a temperature adjusting mechanism, a getter material 42, and a high-frequency coil 43 for heating the getter material are provided. The getter chamber 40, the temperature adjusting mechanism, and the high-frequency coil 43 as a heating mechanism constitute a getter forming apparatus.
[0025]
The front substrate 11 placed in the getter chamber 40 is arranged such that the outer surface thereof faces the panel heater 41 and the metal back 20 faces the getter material 42. Then, the front substrate 11 is quickly cooled by the panel heater 41, and the temperature of the display surface including the metal back 20 and the phosphor screen 15 is adjusted to 200 ° C. or less. In the present embodiment, the surface temperature of the metal back 20 was measured 5 minutes after the front substrate 11 was put into the getter chamber 40, and it was found that the temperature dropped to 120 ° C. When the temperature when the panel heater 41 was not used was measured, the surface temperature of the metal back 20 was 250 ° C.
[0026]
Next, while the surface temperature of the metal back 20 was maintained at about 120 ° C., the getter material 42 was heated and evaporated by the high-frequency coil 43 to form the getter film 22 on the metal back 20. A barium getter was used as the getter material 42, and was vacuum-deposited by induction heating with a high-frequency coil 43. The time required for forming a film to a predetermined film thickness was within one minute, and during that time, the surface temperature of the metal back 20 hardly changed.
[0027]
Next, the front substrate 11 on which the getter film 22 is formed is carried into the sealing chamber 50 without being exposed to the outside air. As shown in FIG. 5, in the sealing chamber 50, a local heating mechanism 51 for locally heating the peripheral portion of the substrate and a sealing mechanism 52 for pressing the substrate are provided. The local heating mechanism 51 has annular heaters 51a and 51b. The inside of the sealing chamber 50 is maintained at a high vacuum of the order of 10 ⁻⁵ Pa by an exhaust pump 54. The rear substrate 12 and the other members constituting the outer vacuum container 10 are carried into the sealing chamber 50 after being subjected to a predetermined process without being exposed to the outside air. The sealing chamber 50, the local heating mechanism 51, and the sealing mechanism 52 constitute a sealing device.
[0028]
Subsequently, the positions of the front substrate 11 and the rear substrate 12 are adjusted so that the phosphor layer 16 and the electron-emitting devices 18 formed on the respective substrates correctly face each other. Until now, the substrate temperature has gradually decreased, and the temperature of the getter film 22 formed on the front substrate 11 has been 110 ° C. In this state, only the peripheral portions of the back substrate 12 and the front substrate 11 are heated to about 180 ° C. by the heaters 51 a and 51 b to melt indium as a sealing material. At this time, the temperature of the getter film 22 is maintained at a melting temperature of indium of 160 ° C. or less. Here, after confirming that the temperature of the getter film 22 is maintained at 110 ° C., the front substrate 11 is pressed toward the rear substrate 12 by the sealing mechanism 52, and the peripheral edge of the front substrate and the side wall are in contacted with indium. 13 was joined.
[0029]
Thereafter, the indium is cooled until solidified, and the vacuum envelope 10 is obtained. As described above, by locally heating and cooling only the sealing portion of the substrate, the sealing operation of the vacuum envelope could be performed in substantially the same required time as in the related art.
[0030]
In the above-described manufacturing process, the temperature of the display surface during the formation of the getter film and after the formation of the getter film, that is, the temperatures of the metal back and the phosphor screen are adjusted to 100 ° C., 140 ° C., 180 ° C., and 220 ° C., respectively. Was manufactured, and the display performance of each FED was evaluated. FIG. 6 shows the result. FIG. 6 shows a change in the luminance with the lapse of the use time, assuming that the luminance of the display image in the initial state of the FED is 100% as the display performance retention rate. As shown in FIG. 6, by performing the gettering step and the sealing step in a state where the temperature of the display surface is adjusted to 200 ° C. or lower, it is possible to obtain an FED that maintains stable display performance for a long time. In addition, when the getter films of the plurality of FEDs were subjected to a destructive test, as shown in FIG. 7, the getter process and the sealing process were performed in a state where the temperature of the display surface was adjusted to 200 ° C. or less, so that the adsorption capability was high. It was confirmed that a getter film could be obtained.
[0031]
In the above-described embodiment, barium is used as the getter material. However, the present invention is not limited to this, and another getter material such as titanium may be used. FIG. 8 and FIG. 9 show the display performance retention and the getter adsorption capability of the FED when titanium is used as the getter material, respectively. In this case as well, high display performance can be obtained by adjusting the display surface of the substrate to 200 ° C. or less during the gettering step and the sealing step.
[0032]
As described above, according to the present embodiment, the getter material has a gas adsorption capacity of 200 ° C. or lower, preferably 160 ° C. or lower at all times from the getter process to the sealing process. Deterioration can be prevented. 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.
[0033]
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements in an implementation stage without departing from the scope of the invention. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiments. Further, components of different embodiments may be appropriately combined.
[0034]
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 sealing material is not limited to indium, and its alloy, other metal materials, frit glass and the like can be selected. 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.
[0035]
The baking step may be performed individually for each member, or a baking chamber may be used individually. At that time, the heating temperature may be set individually. Further, the temperature adjusting mechanism may be installed in a baking chamber or a transfer mechanism between the baking chamber, instead of being installed in the getter chamber. It is also possible to integrate the baking chamber, getter chamber and sealing chamber into one chamber. The present invention is not limited to the FED, and may be applied to the manufacture of another image display device such as a PDP.
[0036]
【The invention's effect】
As described in detail above, according to the present invention, it is possible to prevent a deterioration in the gas adsorption ability of a getter material and to manufacture an image display device capable of maintaining high display performance for a long period of time, a manufacturing apparatus, and a manufacturing method. An image display device manufactured by the manufacturing method can be provided.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an FED as an example of an image display device manufactured by a manufacturing method according to an embodiment of the present invention.
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 baking apparatus used for manufacturing the FED.
FIG. 4 is a cross-sectional view showing a getter forming apparatus used for manufacturing the FED. FIG. 5 is a cross-sectional view showing a sealing apparatus used for manufacturing the FED.
FIG. 6 is a diagram showing the display performance retention of the FED in comparison between the case where the getter is formed at a low temperature and the case where the getter is formed at a high temperature.
FIG. 7 is a graph showing the getter ability of the FED in comparison between the case where the getter is formed at a low temperature and the case where the getter is formed at a high temperature.
FIG. 8 is a diagram showing the display performance retention of the FED when titanium is used as a getter material, when the getter is formed at a low temperature and when it is formed at a high temperature.
FIG. 9 is a graph showing the getter adsorption capacity of the FED when titanium is used as a getter material, when the getter is formed at a low temperature and when the getter is formed at a high temperature.
[Explanation of symbols]
10: vacuum envelope, 11: front substrate, 12: rear substrate,
13 ... side wall, 15 ... phosphor screen, 18 ... electron-emitting device,
20: metal back 20: getter film 30: baking chamber
31 ... exhaust pump, 32 ... heating mechanism, 40 ... getter chamber,
41: temperature adjustment mechanism, 42: getter material, 43: high-frequency coil,
50: sealing chamber 51: sealing mechanism 52: local heating mechanism

Claims (12)

In a method for manufacturing an image display device including an envelope having a front substrate provided with a display surface and a rear substrate disposed opposite to the front substrate,
A getter step of forming a getter film on the display surface, and a sealing step of forming an envelope by sealing a peripheral portion of the back substrate and the front substrate on which the getter film is formed,
A method for manufacturing an image display device, comprising: performing the getter step in a state where the temperature of the display surface is adjusted to 200 ° C. or lower, and maintaining the temperature of the display surface at 200 ° C. or lower after the getter step. 2. The method according to claim 1, wherein the gettering step is performed after baking the front substrate and the rear substrate at a temperature of 300 [deg.] C. or more. A sealing material is provided along a peripheral portion of at least one of the front substrate and the rear substrate, and the getter step and the sealing step are performed in a state where the temperature of the display surface is adjusted to a melting temperature of the sealing material or lower. The method according to claim 1, wherein the method is performed. 4. The method according to claim 3, wherein the gettering step and the sealing step are performed in a state where indium is used as the sealing material and the temperature of the display surface is adjusted to 160 ° C. or lower. 5. 4. The method according to claim 3, wherein, in the sealing step, a peripheral portion of the at least one substrate provided with the sealing material is locally heated to a melting temperature of the sealing material or higher and sealed. 5. 5. The method for manufacturing an image display device according to item 4. 6. The method according to claim 1, wherein the getter film is formed of barium. The method according to any one of claims 1 to 6, wherein the gettering step and the sealing step are performed in a vacuum atmosphere. In an apparatus for manufacturing an image display device including an envelope having a front substrate provided with a display surface and a rear substrate disposed opposite to the front substrate,
A getter forming apparatus having a temperature adjustment mechanism for adjusting the temperature of the display surface, and forming a getter film on the display surface in a state where the temperature of the display surface is adjusted to 200 ° C. or less;
An image display device comprising: a sealing device for sealing peripheral portions of the back substrate and the front substrate on which the getter film is formed, while maintaining the temperature of the display surface at 200 ° C. or lower. Manufacturing equipment. The getter forming apparatus includes a getter chamber that houses the front substrate, an exhaust pump that exhausts the inside of the getter chamber to a vacuum, and a heating device that heats a getter material provided to face the display surface. 9. The apparatus according to claim 8, wherein the temperature adjustment mechanism includes a heater disposed in the getter chamber so as to face the front substrate. The sealing device includes a sealing chamber that houses the front substrate and the rear substrate in a state of facing each other, an exhaust pump that evacuates the sealing chamber to a vacuum, and a peripheral edge of at least one of the front substrate and the rear substrate. A heater for locally heating the portion, a heating device for heating a getter material provided to face the display surface, and a sealing mechanism for pressing the front substrate and the rear substrate in directions approaching each other. The apparatus for manufacturing an image display device according to claim 8, wherein: The apparatus according to any one of claims 8 to 10, further comprising a baking device for baking the front substrate and the rear substrate at a temperature of 300 ° C or higher. An image display device according to any one of claims 1 to 7, further comprising an envelope having a front substrate provided with a display surface and a rear substrate opposed to the front substrate. Image display device.

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