JP2007280763A - Manufacturing method of image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an image display device in which gas contained in the inside or on the surface of a substrate can be degassed efficiently and superior display performance can be maintained over a long period. <P>SOLUTION: In the manufacturing method of the image display device equipped with an envelope consisting of a plurality of substrates, high temperature state electrons are irradiated against at least one of the substrates 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of manufacturing an image display device including a front substrate and a rear substrate that are arranged to face each other.

  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 by electron irradiation of a field emission electron-emitting device, and surface conduction electron that emits a phosphor by electron irradiation of a surface-conduction electron-emitting device. Emission displays (hereinafter referred to as SEDs) have been developed.

  For example, the FED generally has a front substrate and a rear substrate that are arranged to face each other with a predetermined gap, and these substrates are surrounded by a vacuum by surrounding peripheral portions to each other via a rectangular frame 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 10 kV, for example, is applied as an anode voltage to the phosphor screen. An image is displayed by irradiating red, green, and blue phosphors constituting the phosphor screen with electrons 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 vacuum envelope. That is, in the FED, electrons collide with the phosphor on the front substrate to cause the phosphor to emit light. At this time, a large amount of emitted gas is generated, and the degree of vacuum inside the vacuum envelope is greatly deteriorated. As a result, the electron emission characteristics of the electron-emitting device formed on the back substrate are deteriorated, resulting in a decrease in luminance, a deterioration in color reproducibility, and a shortened life. As a result, it is difficult to realize a long-life image display device with excellent display performance. As a countermeasure against this, it is necessary to reduce the amount of gas released inside the FED in a product state.

 Further, in order to maintain a high degree of vacuum in the vacuum envelope for a long period of time, a getter layer that adsorbs undesired gas molecules is usually provided inside the envelope. As such a getter layer, 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 1).

Moreover, before it becomes a product, the front substrate and the rear substrate are put into a vacuum chamber, and a high temperature treatment is performed at 300 to 450 ° C. to obtain a substrate degassing effect (see, for example, Patent Document 2).
JP-A-11-191378 JP 2001-229824 A

  As described above, when a gas is adsorbed by providing a getter layer in the envelope, the gas adsorption amount of the getter has an allowable amount, and the effectiveness is lost for a certain amount of gas. For this reason, it becomes difficult to maintain high vacuum characteristics in the vacuum envelope for a long time.

  In addition, when degassing is performed by heating the substrate, a sufficient effect until reaching the desired performance is not obtained only by the high temperature treatment. As a solution to this problem, it is conceivable to further increase the heating temperature. In this case, however, there arises a problem of manufacturing cost and a problem of deformation of the substrate.

  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 maintains high display performance over a long period of time.

  In order to achieve the above object, a method for manufacturing an image display device according to an aspect of the present invention is a method for manufacturing an image display device including an envelope constituted by a plurality of substrates, and includes at least one of the substrates. On the other hand, it is characterized by irradiating electrons in a high temperature state.

  An image display device manufacturing method according to another aspect of the present invention is a method for manufacturing an image display device including an envelope constituted by a plurality of substrates, wherein the substrate subjected to a degassing process by heating is provided. It is characterized by irradiating electrons in a high temperature state.

  According to the above configuration, it is possible to obtain a method for manufacturing an image display device capable of efficiently degassing the gas contained inside or on the surface of the substrate and maintaining high display performance over a long period of time.

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 this manufacturing method, an SED equipped with a surface conduction electron-emitting device will be described as an example.

  As shown in FIGS. 1 and 2, this SED includes a front substrate 11 and a rear substrate 12 each made of a rectangular glass plate as insulating substrates, and these substrates are arranged to face each other with a gap of 1 to 3 mm. Has been. The front substrate 11 and the back substrate 12 constitute a flat rectangular vacuum envelope 10 whose peripheral portions are joined to each other via 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 portion of the front substrate 11 and the peripheral edge portion of the rear substrate 12 by, for example, a sealing material 23 such as low melting glass or low melting metal, and these substrates are bonded to each other. is doing.

  A plurality of spacers 14 are provided inside the vacuum envelope 10 in order to support an atmospheric pressure load applied to the front substrate 11 and the rear substrate 12. As the spacer 14, a plate-like or columnar spacer or the like can be used.

  A phosphor screen 15 is formed on the inner surface of the front substrate 11 as an image display surface. The phosphor screen 15 includes red, green, and blue phosphor layers 16 and a light shielding layer 17 formed in a matrix. The phosphor layer 16 is formed in a stripe shape or a dot shape. A metal back 20 made of an aluminum film or the like is formed on the phosphor screen 15, and a getter film 22 is formed on the metal back.

  On the inner surface of the back substrate 12, a number of surface conduction electron-emitting devices 18 that emit electrons are provided as electron sources that excite 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 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. Further, a large number of wirings 21 for supplying a potential to the electron-emitting device 18 are provided on the inner surface of the rear substrate 12 in a matrix shape, and end portions thereof are drawn out of the vacuum envelope 10.

  In such an SED, when an image is displayed, an anode voltage is applied to the phosphor screen 15 and the metal back 20 and electrons of a predetermined current amount are emitted from the electron emitter 18. Then, the electrons emitted from the electron emitter 18 are accelerated by the anode voltage and collide with the phosphor screen. As a result, the phosphor layer 16 of the phosphor screen 15 is excited to emit light and display a color image.

Next, a method for manufacturing the SED configured as described above will be described.
First, the front substrate 11 having the phosphor screen 15 and the metal back 20 formed on the inner surface and the rear substrate 12 having the electron-emitting device 18 are prepared. In addition, a side wall 13 and a plurality of spacers 14 are bonded on the back substrate 12 in advance. Further, for example, a sealing material is filled along the entire upper surface of the side wall 13. Here, indium was used as the sealing material. Subsequently, the front substrate 11 and the back substrate 12 are heat-treated in a processing chamber to perform a degassing process.

  As shown in FIG. 3, a plate-like heater 33 is provided in the processing chamber 30. For example, two electron emission sources 31 are provided in the processing chamber 30. These electron emission sources 31 irradiate electrons toward the substrate. An exhaust pump 36 is connected to the processing chamber 30 so that the inside of the chamber can be evacuated.

  In the degassing process, for example, the front substrate 11 is put into the processing chamber 30 and placed facing the heater 33. Thereafter, the inside of the processing chamber 30 is evacuated by the exhaust pump 36 to make a vacuum atmosphere. Subsequently, the front substrate 11 is heated to 200 to 550 ° C., preferably 250 to 350 ° C. by the heater 33, and the gas contained in the front substrate 11 and on the surface is released. In addition, a voltage of 10 kV or higher is applied from the power source 34 to the front substrate 11 while the substrate temperature of the front substrate 11 is at a high temperature of 200 ° C. or higher, and electrons are irradiated from the electron emission source 31 to the front substrate 11. Here, electrons are irradiated on the surface side of the front substrate 11 on which the phosphor screen 15 is formed. Gas emission from the front substrate 11 is promoted by irradiation with electrons. At this time, since the temperature of the front substrate 11 is maintained at 200 ° C. or higher, the gas degassed from the front substrate can be prevented from being adsorbed again on the front substrate.

The amount of current of electrons irradiating the front substrate 11 is higher than the amount of current of electrons emitted from the electron-emitting device 18 during normal image display of the SED, which is defined by the amount of charge that is the product of current density and time. For example, the electron irradiation treatment is performed under the condition that the current density is ² mA / cm ² for 3 hours. This value corresponds to a charge amount of 22 C / cm ² and corresponds to 1/10 of the panel life of the product.

By setting the input charge range to 1 C / cm ² or more, the effect of degassing the substrate can be obtained, and in order to prevent deterioration of the luminous efficiency of the phosphor, it is set to 50 C / cm ² or less. Further, the electron beam is scanned so that the entire surface of the front substrate 11 is irradiated, or electrons are irradiated while the front substrate 11 is moved relative to the electron emission source 31. During the degassing process, evacuation by the exhaust pump 36 is continued, and the gas component desorbed from the substrate is discharged from the processing chamber 30 to the outside, and the inside of the processing chamber is maintained in a clean vacuum state.

  During the degassing process, the atmosphere in the processing chamber 30 is preferably evacuated, but it is also possible to select air or another gas atmosphere depending on time and temperature.

  The back substrate 12 is also degassed in the processing chamber 30 as described above. After performing degassing for a predetermined time, a getter film is formed on the front substrate 11. Thereafter, the front substrate 11 and the rear substrate 12 are sealed with the side wall 13 in between, and the vacuum envelope 10 is formed.

  The present inventor uses the processing chamber 30 described above to irradiate electrons with the substrate temperature heated to 300 ° C. and degass the substrate in this embodiment, and the electrons at a substrate temperature of room temperature. Comparative substrates that were irradiated and degassed were prepared, and the SED envelope according to the present embodiment and the envelope as a comparative example were formed using these substrates. Then, these SEDs were driven, and the amounts of gas released when a certain time had elapsed were compared.

  The result is shown in FIG. From this figure, as in this embodiment, the substrate degassed by irradiating electrons with the substrate temperature heated to 300 ° C. has a residual gas release amount as compared with the case of using the substrate of the comparative example. I understand that there are few. Therefore, according to the present embodiment, the substrate can be efficiently degassed, the amount of gas released inside the SED during operation can be reduced, and the inside of the vacuum envelope can be maintained at a high degree of vacuum. Possible SEDs can be obtained. Thereby, an SED capable of maintaining high display performance over a long period of time can be obtained.

  In addition, this invention is not limited to the said embodiment, In the implementation stage, it can embody by modifying a component in the range which does not deviate from the summary. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  Furthermore, the present invention is not limited to SED, and may be applied to other image display devices such as FED and PDP.

FIG. 1 is a perspective view showing an 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 a sectional view schematically showing a processing chamber used in the manufacturing method according to the embodiment of the present invention. FIG. 4 is a diagram showing a comparison of residual released gas amounts between a substrate according to the present embodiment and a substrate according to a comparative example.

Explanation of symbols

10 ... Vacuum envelope, 11 ... Front substrate, 12 ... Back substrate, 13 ... Side wall,
14 ... spacer, 15 ... phosphor screen, 16 ... phosphor layer,
18 ... electron-emitting device, 20 ... metal back, 30 ... processing chamber,
31 ... Electron emission source, 33 ... Heater, 34 ... Power supply

Claims (7)

In a method for manufacturing an image display device including an envelope constituted by a plurality of substrates,
A method of manufacturing an image display device, wherein at least one of the substrates is irradiated with electrons at a high temperature.   The method for manufacturing an image display device according to claim 1, wherein at least one of the substrates is irradiated with electrons at a temperature of 200 ° C. to 550 ° C. 5.   The method for manufacturing an image display device according to claim 2, wherein the substrate is irradiated with electrons while the substrate is at a temperature of 250 ° C. to 350 ° C. 5.   The method for manufacturing an image display device according to claim 1, wherein the substrate is heated in the air, in a vacuum atmosphere, or in a gas atmosphere. ^{2. The} method of manufacturing an image display device according to claim 1, wherein a charge amount of the electron irradiation is 1 to 50 C / cm < ² >.   2. The method of manufacturing an image display device according to claim 1, wherein the substrate is irradiated with electrons when the substrate is heated at 200 ° C. to 550 ° C. when the temperature reaches a maximum temperature or when the temperature falls. In a method for manufacturing an image display device including an envelope constituted by a plurality of substrates,
A method of manufacturing an image display device, comprising: irradiating a substrate that has been degassed by heating with electrons at a high temperature.

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