JPH11329243A - Manufacture of image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an image display device for removing impurities such as water in an vacuum atmosphere in an activating process, and to heighten electron emission efficiency of elements, then reducing electric power consumption. SOLUTION: In this manufacturing method of an image display device, where plural electron emission elements are arranged in a vacuum container, an activating process is constituted by introducing activated gas in a vacuum container and by impressing pulse voltage on the electron emission elements for activating them. Here, a getter provided in the vacuum container is activated, prior to the activated gas is introduced in the vacuum container.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing an image display device using an electron beam.

[0002]

2. Description of the Related Art Conventionally, liquid crystal display devices, EL display devices, and plasma display panels (PDPs) have been put to practical use as flat panel image display devices. However, these image display devices are inferior in terms of viewing angle, contrast ratio, and brightness as compared with a generally used cathode ray tube (CRT).

For this reason, several electron beam acceleration type flat panel displays have been proposed as image display devices. Among them, devices that can obtain electron emission with a simple structure include, for example, MIElinso
n), etc. [Radio Engineering Electron Physics (Radio Eng. Electr
on. Phys.) Volume 10, pp. 1290-1296, 1965
Year] is known. This utilizes the phenomenon that electron emission occurs when a current flows in a small area thin film formed on a substrate in parallel with the film surface, and is generally called a surface conduction electron-emitting device. .

As the surface conduction type electron-emitting device, one using an SnO ₂ thin film developed by Elinson et al. Or one using a carbon thin film [Hisashi Araki et al .: “Vacuum”, Vol. 26, No. 1, 22 (1983)]. These surface conduction electron-emitting devices are (1) that high electron emission efficiency is obtained, (2) that their structure is simple and that they are easy to manufacture, and (3) that many devices are mounted on the same substrate. There are advantages such as being able to form an array.

Hereinafter, a conventional method for manufacturing a flat panel type image display device using a planar cold cathode as the surface conduction electron-emitting device will be described. Before showing a method of manufacturing the image display device, its structure will be described with reference to the drawings.

FIG. 2 is a schematic diagram showing a schematic configuration of an image display device using a surface conduction electron-emitting device. As shown in FIG. 2, the image display device includes a face plate 1 as an image display surface made of an insulating material such as glass, a rear plate 2 disposed opposite to the face plate 1, and an insulating material made of glass or the like. Outer frame 3 and face plate 1
And it joins with low melting glass in the peripheral part of the rear plate 2, and forms an airtight container. The pressure applied to the airtight container from the outside is supported by the outer frame 3 and the atmospheric pressure support column 7, and the distance between the face plate 1 and the rear plate is kept constant. The distance between the face plate 1 and the rear plate 2 was 10 mm in the case of the present embodiment.

A phosphor 4 and an aluminum thin film 5 are formed on the face plate 1, and a high voltage of 1 to 10 kV is applied to the aluminum thin film 5 by an external high voltage power supply (not shown).
Reference numeral 8 denotes a gas introduction pipe for introducing the gas during the activation process, and also exhausts the airtight container. The introduced activation gas activates the electron-emitting device 6. Reference numeral 9 denotes an exhaust pipe for exhausting the airtight container, which is connected to a vacuum pump via a valve. Reference numeral 10 denotes a getter provided to maintain the degree of vacuum in the container after sealing the airtight container. In this embodiment, Ba-Al-Ni is used.
(Barium, aluminum, nickel) evaporation type getter was used. Reference numeral 11 denotes a shielding plate for preventing the getter material from diffusing into the image display area when the getter material is flashed (activated).

FIG. 3 shows a surface conduction electron-emitting device which is an electron source of an image display device. The electron source has device electrodes 12 and 13 formed on a rear plate 2, and the electrodes are arranged at a constant distance (about 2 μm) between the electrodes. Device electrode 12
An organic palladium thin film 14 is formed on and 13, and a crack 15 is formed in the center of the organic palladium thin film, and the crack serves as an electron emitting portion 15.

A method for manufacturing the above-described image display device will be described. An element portion is formed on the rear plate 2 in advance.
The element portion is composed of wiring, element electrodes 12 and 13, and a PdO (palladium oxide) thin film 14. The low melting glass is fired on the rear plate 2 on which the element portion is formed, and the getter 10 and the atmospheric pressure support column 7 are fixed. A rear plate 2 on which an electron-emitting device 6, a getter 10, and an atmospheric pressure support column 7 are formed; a phosphor 4;
A low-melting glass is applied to the joint between the outer frame 3 and the peripheral portion of the face plate 1 on which is formed. Further, around the outer frame 3, there are provided portions where the gas introduction pipe 8 and the exhaust pipe 9 are arranged, and the installation portion is also coated with low melting point glass. These members are sealed by firing the low-melting glass to complete an airtight container. FIG. 6 is a flowchart showing a manufacturing process for completing the image display device through the getter flash process after sealing.

After all the members are sealed, the residual gas in the hermetic container is exhausted from the gas introduction pipe 8 and the exhaust pipe 9. When the pressure in the hermetic container reaches about 1 × 10 ⁻⁵ Torr or less, forming processing (voltage application to element electrodes 12 and 13)
Is performed to form a crack 15 as an electron emission portion in the PdO thin film 14. Then, the pressure in the hermetic container is about 1 × 10 ^-7
When the pressure reaches Torr or less, the pressure in the airtight container is 5 × 10
Benzonitrile gas inlet pipe 8 so that ^-6 Torr
Then, the gas is exhausted from the exhaust pipe 9 and the element is activated.

The activation process is a process of introducing an activation gas into an airtight container and applying a pulse voltage between device electrodes. By performing this activation process, the efficiency of electron emission is increased, and the brightness of the image display device is improved. After the activation of the device, a vacuum high-temperature baking process is performed to perform a degassing process. The temperature of the airtight container is raised to 200 ° C. and maintained for 5 to 10 hours. Thereafter, the temperature is lowered to room temperature. Then, after sealing the gas introduction pipe 8 and the exhaust pipe 9, the getter 11 is flashed (activated) by induction heating. The getter 11 has an exhausting effect. By activating the getter 11, the residual gas in the hermetic container is captured, and the inside of the hermetic container is maintained at a high vacuum for a long time.

[0012]

In the above-mentioned image display device, it is important to reduce power consumption as much as possible. For that purpose, it is necessary to increase the electron emission efficiency of the device. In order to improve the electron emission characteristics of the device, it is necessary to optimize the type of the activating gas or the driving conditions applied to the device during activation.

There are optimum driving conditions applied to the element during activation depending on the type of the activating gas and the pressure of the activating gas. As for the activating gas, as described in JP-A-8-7749, the following carbonized compound which is liquid at normal temperature is suitable. For example, butadiene, n
-Hexane, 1-hexane, benzene, toluene, O-xylene, benzonitrile, chloroethylene, acetone and the like.

It has been found that when the partial pressure of water is high during the activation step, the emission efficiency of the device decreases. Moisture is dissolved in these carbonized compounds. Therefore, it is necessary to remove water in the activation gas as much as possible. Examples of a method for removing moisture in the activated gas include a method for removing the moisture in the solution in advance by a freeze-drying method in a liquid state and a method for removing the gas in a gas state by using a gas filter for removing moisture. Even if the water in the activation gas is removed by the method described above, the electron emission efficiency of the device is insufficient from the viewpoint of the power consumption of the image display device.

The present invention has been made to solve the above-mentioned problems, and removes impurities such as moisture in a vacuum atmosphere during an activation step to increase the electron emission efficiency of the device and reduce the power consumption of an image. It is an object of the present invention to provide a method for manufacturing a display device.

[0016]

The above objects and objects are solved and achieved by the present invention described below. That is, the present invention relates to a method for manufacturing an image display device comprising a plurality of electron-emitting devices arranged in a vacuum-tight container, wherein an activation gas is introduced into the vacuum-tight container to apply a pulse voltage to the electron-emitting devices. In the activation step of performing the activation process, the activation process of the getter provided in the vacuum hermetic container is performed before introducing the activation gas into the vacuum hermetic container. This discloses a manufacturing method.

According to the method of manufacturing an image display device of the present invention, the getter provided in the confidential container is partially activated before introducing the activating gas into the vacuum confidential container, so that the activation process can be performed during the activation step. This removes impurities other than the activation gas component and performs an element activation step.

(Function) According to the method of manufacturing an image display device of the present invention, if the getter is in an activated state during activation, impurities of the carbonized compound gas can be removed from the adsorption characteristics of the getter. The pumping speed of the carbonized compound getter is not more than 1/30 of that of a gas such as water or oxygen. Therefore, use of a getter is an optimal method for removing impurities from the carbonized compound.

This makes it possible to remove impurities such as water which degrade the electron emission characteristics of the device in the device activation step, and to provide an image display device with high electron emission efficiency of the device.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments based on the drawings, but the present invention is not limited thereto. [Embodiment 1] FIG. 1 shows a block flow diagram from the sealing to the getter flash step in the manufacturing process of the image display device according to the present invention.

After all the members are sealed, the residual gas in the airtight container is exhausted from the gas introduction pipe 8 and the exhaust pipe 9. When the pressure in the hermetic container reaches about 1 × 10 ⁻⁵ Torr or less, forming processing (voltage application to element electrodes 12 and 13)
Is performed to form a crack 15 as an electron emission portion in the PdO thin film 14. Thereafter, the pressure in the airtight container is reduced to about 1 × 10 ^−7.
When the pressure reaches Torr or less, a part of the getter 10 in the confidential container is activated (flashed). Next, benzonitrile is introduced from the gas introduction pipe 8 and exhausted from the exhaust pipe 9 so that the pressure in the airtight container becomes 5 × 10 ⁻⁶ Torr, and the element is activated.

The activation process is a process of introducing an activation gas into an airtight container and applying a pulse voltage between device electrodes. By performing this activation process, the efficiency of electron emission is increased, and the brightness of the image display device is improved. After activation of the device, vacuum high-temperature baking is performed to perform degassing.
After the baking process, the exhaust pipe 9 and the gas introduction pipe 8 are sealed off. Thereafter, the getter 11 is flushed (activated) by induction heating. The getter 11 has an exhausting effect. By activating the getter 11, the residual gas in the hermetic container is captured, and the inside of the hermetic container is maintained at a high vacuum for a long time. Thus, the image display device is completed.

The operation of the image display device configured as described above will be described below. When a driving pulse voltage is applied to the element electrodes 12 and 13 of the electron-emitting device 2 by an external driving circuit (not shown) in the image display device maintained at a predetermined degree of vacuum, electrons are emitted from the electron-emitting portion 15. The emitted electrons are accelerated by the voltage (1 to 10 kV) applied to the phosphor 4 and the aluminum thin film 5 and collide with the aluminum thin film 5. The collision excites the phosphor 4 and an image is displayed on the image display surface.

Element characteristics were evaluated in order to evaluate the characteristics of the image display device manufactured by the manufacturing method of the present embodiment and the characteristics of the image display device manufactured by the conventional manufacturing method. Drive voltage between device electrodes is 15V, pulse width is 100μ
A, a rectangular wave having a period of 10 mS was applied. Further, an acceleration voltage of 4 kV was applied to the phosphor and the aluminum thin film. If the current flowing between the device electrodes 12 and 13 at this time is If, and the current flowing through the phosphor and the aluminum thin film is Ie, the electron emission efficiency η (%) is η (%) = (Ie / If) × 100 Becomes In this embodiment, η was 0.5 to 0.6%.
In the conventional manufacturing method, η was 0.3 to 0.4%.

From these results, it can be seen that the device characteristics of the image display device manufactured by the manufacturing method of this embodiment have higher electron emission efficiency than the conventional example. This is because, in the activation step, impurities other than the activation gas in the confidential container can be removed by activating the getter in the vacuum confidential container, and the impurities in the carbon film laminated in the activation step are removed. This is probably because the electron scattering efficiency has increased.
From this, the effect of the method for manufacturing an image display device according to the present embodiment is clear.

[Embodiment 2] FIG. 4 shows a block flow diagram from the sealing to the completion of getter flash in the manufacturing process of the image display device according to the present invention. FIG. 5 shows a schematic configuration of an image display apparatus according to the present embodiment.

After all the members are sealed, the residual gas in the airtight container is exhausted from the gas introduction pipe 8 and the exhaust pipe 9. When the pressure in the hermetic container reaches about 1 × 10 ⁻⁵ Torr or less, forming processing (voltage application to element electrodes 12 and 13)
Is performed to form a crack 15 as an electron emission portion in the PdO thin film 14. Thereafter, the pressure in the airtight container is reduced to about 1 × 10 ^−7.
When the pressure reaches Torr or lower, the non-evaporable getter 16 containing Zr-Ba-Fe as a main component in the confidential container is activated by electric heating. Next, when the pressure in the airtight container is 5 × 10 ⁻⁶ To
Benzonitrile is introduced from the gas introduction pipe 8 and exhausted from the exhaust pipe 9 so as to achieve rr, and the element is activated.

The activation process is a process of introducing an activation gas into an airtight container and applying a pulse voltage between device electrodes. By performing this activation process, the efficiency of electron emission is increased, and the brightness of the image display device is improved. After the activation of the device, a vacuum high-temperature baking process is performed to perform a degassing process. After the baking process, the non-evaporable getter 16 used in the activation step is subjected to a reactivation process by electric heating. The exhaust pipe 9 and the gas guide pipe 8 are cut off. Thereafter, the getter 10 is flashed (activated) by induction heating.
Let it. Thus, the image display device is completed.

The operation of the image display device configured as described above will be described below. When a driving pulse voltage is applied to the element electrodes 12 and 13 of the electron-emitting device 2 by an external driving circuit (not shown) in the image display device maintained at a predetermined degree of vacuum, electrons are emitted from the electron-emitting portion 15. The emitted electrons are accelerated by the voltage (1 to 10 kV) applied to the phosphor 4 and the aluminum thin film 5 and collide with the aluminum thin film 5. The collision excites the phosphor 4 and an image is displayed on the image display surface.

The device characteristics were evaluated in order to evaluate the characteristics of the image display device manufactured by the manufacturing method of this embodiment and the image display device manufactured by the conventional manufacturing method. Drive voltage between device electrodes is 15V, pulse width is 100μ
A, a rectangular wave having a period of 10 mS was applied. Further, an acceleration voltage of 4 kV was applied to the phosphor and the aluminum thin film. If the current flowing between the device electrodes 12 and 13 at this time is If and the current flowing through the phosphor and the aluminum thin film is Ie, the electron emission efficiency η (%) is η (%) = (Ie / If) × 100 Becomes In this embodiment, η was 0.5 to 0.6%.
In the conventional manufacturing method, η was 0.3 to 0.4%.

From these results, it can be seen that the device characteristics of the image display device manufactured by the manufacturing method of the present embodiment have higher electron emission efficiency than the conventional example. This is because, in the activation step, impurities other than the activation gas in the confidential container can be removed by activating the getter in the vacuum confidential container, and the impurities in the carbon film laminated in the activation step are removed. This is probably because the electron scattering efficiency has increased.
From this, the effect of the method for manufacturing an image display device according to the present embodiment is clear.

In this embodiment, the getter used for removing impurities in the activation step is a non-evaporable getter, so that it can be used again as a getter if it is reactivated after the activation step. . Therefore, the vacuum state in the confidential container after the sealing is completed can be favorably maintained, and the element can be operated stably for a long time.

In the present embodiment, the step of reactivating the non-evaporable getter is performed after the completion of the baking process, but may be performed after the completion of the activation step and is not limited to this.

Furthermore, if the activation temperature of the non-evaporable getter is relatively low, the baking processing temperature is set to be higher than the activation processing temperature of the non-evaporable getter, so that the activation processing of the non-evaporable getter is simultaneously performed. It is also possible. As described above, there is no problem if the non-evaporable getter can be reactivated without independently performing the non-evaporable getter reactivation process.

In this embodiment, Ba-A is used as the getter material.
Although the l-Ni evaporation type was used, for example, a getter containing Ti (titanium), Zr (zirconium), Fe (iron), Ni (nickel), V (vanadium) as a main component, or the like may be used. It is not limited to the evaporating type and the non-evaporating type.

In this embodiment, benzonitrile is used as the activating gas for the electron-emitting device. However, the present invention is not particularly limited as long as it is a gas for activating the electron-emitting device. As the activating gas species, a carbonized compound is effective.

[0037]

As described above, according to the present invention, by activating the getter provided in the confidential container before the activation processing of the element, impurities other than the activated gas component during the activation step can be obtained. Can be efficiently removed, the electron emission efficiency of the element can be improved, and a method of manufacturing an image display device with low power consumption can be provided.

[Brief description of the drawings]

FIG. 1 is a process for manufacturing an image display device of the present invention (Example 1).
FIG.

FIG. 2 is a schematic diagram showing a schematic configuration of an image display device.

FIG. 3 is a schematic diagram showing an outline of a surface conduction electron-emitting device of the image display device.

FIG. 4 is a view showing a manufacturing process of an image display device according to the present invention (Example 2).
FIG.

FIG. 5 is a schematic diagram showing a schematic configuration of an image display device of the present invention.

FIG. 6 is a block flow diagram showing a manufacturing process of a conventional image display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Face plate 2 Rear plate 3 Outer frame 4 Phosphor 5 Aluminum thin film 6 Electron emission element 7 Atmospheric pressure support column 8 Gas introduction pipe 9 Exhaust pipe 10 Getter 11 Shielding plate 12, 13 Element electrode 14 Palladium thin film 15 Electron emission part 16 Non Evaporable getter

Claims (3)

[Claims] 1. A method for manufacturing an image display device comprising a plurality of electron-emitting devices arranged in a vacuum-tight container, wherein an activation gas is introduced into the vacuum-tight container and a pulse voltage is applied to the electron-emitting devices. In the activation step of performing the activation process,
A method for manufacturing an image display device, comprising performing an activation process of a getter provided in a vacuum-tight container before introducing the activation gas into the vacuum-tight container. 2. The method according to claim 1, wherein the getter provided in the vacuum-tight container is a non-evaporable getter. 3. The screen according to claim 1, wherein after activating the non-evaporable getter provided in the vacuum-tight container, the non-evaporable getter is reactivated. A method for manufacturing a display device.