JP2000251717A - Manufacture of image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a stable image display device with a long life and a high quality capable of preventing reduction of a suction characteristic of a non-evaporation getter by flowing a sufficient inert gas to the inside of an envelope to avoid an influence to the non-evaporation getter without injecting a gas to the outside of the envelope in an image indication device. SOLUTION: An envelope is constituted by arranging a front substrate 2 provided with an electrode and a phosphor to indicate an image and a back substrate 1 provided with an element electrode to emit an electron at a predetermined space. A non-evaporation getter is arranged in an image display area of the envelope, preferably on a wiring connected to the element electrode 8. When an image display device in which a plurality of members constituting the envelope are sealed is manufactured, the envelope is installed in a vacuum container and is heated and sealed while independently controlling their internal pressures.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a flat type image display device for forming an image by exciting a phosphor, and more particularly to a method of sealing an envelope.

[0002]

2. Description of the Related Art In an image display device, an electron beam emitted from an electron source is applied to a phosphor as an image display member to cause the phosphor to emit light, thereby displaying an image. The interior of the envelope containing the electron source and the image forming member must be kept at a high vacuum.

When a gas is generated inside the vacuum envelope and the pressure increases, the effect depends on the type of the gas and the degree of the pressure increase. However, the emission due to deterioration and damage of the electron source is reduced, and furthermore, The discharge can cause destruction of the device.

[0004] Usually, the envelope of the image display device is combined with glass members, and the joint is heated and sealed using an adhesive such as low melting point glass. Then, in order to maintain a high vacuum after the sealing is completed, the adsorbing ability is used by activating the getter installed in the envelope. In particular, as means for suppressing a pressure increase due to local gas release, a method of distributing a non-evaporable getter on wiring or an image display region connected to an electron-emitting device in an envelope has been proposed. (See JP-A-09-082245).

In order to seal the envelope of the image display device with low-melting glass, the temperature of the envelope to be sealed must be 400 ° C.-500 ° C.
It is necessary to raise to about ° C. However, the temperature of the non-evaporable getter installed inside the envelope was 400 ° C-5
Since the temperature rises to about 00 ° C., activation of the non-evaporable getter itself proceeds. Therefore, when sealing is performed in the atmosphere,
The adsorption capacity of the enclosed non-evaporable getter deteriorates rapidly, and after the sealing, the adsorption property is much worse than the original adsorption characteristics of the non-evaporable getter, which is intended to adsorb the residual gas inside. Only the function can be exhibited, and it is not sufficiently useful for maintaining a high vacuum in the envelope after sealing.

Therefore, as a countermeasure, it has been proposed to seal the envelope of the image display device in a vacuum or in an inert gas (see Japanese Patent Application Laid-Open No. 7-94102). However, when sealing in a vacuum, if only the inside of the envelope where the non-evaporable getter is placed is evacuated and sealed, the frit glass that has fluidized near the sealing temperature will be inside and outside the envelope. Because it is drawn inside due to the pressure difference,
It is difficult to seal the vacuum envelope with frit glass, and it is necessary to put the entire envelope in a vacuum container. If so, the frit glass fluidized near the sealing temperature foams and remains as bubbles even after solidification. For this reason, it is also difficult to make the envelope airtight by sealing with frit glass.

In addition, when sealing is performed in an inert gas, the deterioration of the non-evaporable getter is smaller than in the case of sealing in the air, but the temperature becomes high at the time of sealing, and the outer periphery of the image display device is surrounded. The non-evaporable getter is also deteriorated by the gas released from the members constituting the vessel into the envelope.

As a method of removing gas generated from members constituting the envelope from the envelope, a method of flowing a non-combustible non-oxidizing gas such as nitrogen into the envelope has been proposed (see, for example, Japanese Patent Application Laid-Open No. H11-157556). See JP-A-07-37506).

[0009]

However, if an attempt is made to secure the flow rate of the non-flammable non-oxidizing gas necessary to avoid the influence on the non-evaporable getter, the pressure inside the envelope increases, and the sealing is performed. Since there is a fear that the gas may break through the low-melting glass fluidized near the temperature and blow out to the outside, it is difficult to seal the envelope by frit glass.

As a method for preventing the blow-out from the inside, a method has been proposed in which a gas is blown from the outside to the bonding portion on the outer periphery of the envelope (see Japanese Patent Application Laid-Open No. 06-139934). In order to blow the gas so that the received force becomes uniform, there is a problem that the structure and design of the device for that purpose become complicated.

The present invention has been made on the basis of the above circumstances. In an image display device, a non-evaporable type is provided on a wiring of an electron source substrate or at a required position in an envelope such as an image display area. In the structure equipped with a getter, when heating and sealing the envelope, the gas outside the envelope is controlled by controlling the pressure outside the envelope independently of the pressure inside the envelope. It is possible to flow an inert gas sufficient to avoid the influence on the non-evaporable getter inside the envelope without blowing out to the inside of the envelope, thereby preventing a decrease in the adsorption characteristics of the non-evaporable getter, An object of the present invention is to provide a method for manufacturing a stable, long-life, high-quality image display device.

[0012]

Therefore, in the present invention,
A front substrate provided with electrodes and a phosphor for displaying an image, and a back substrate provided with element electrodes for emitting electrons are arranged at a predetermined interval from each other to form an envelope. In the image display area of the envelope, a non-evaporable getter is arranged, and when manufacturing an image display device in which a plurality of members constituting the envelope are sealed, the envelope is placed in a vacuum container. The enclosure is heated and sealed while independently controlling the pressure inside them.

Therefore, since the envelope is installed inside the vacuum vessel, when a plurality of members constituting the envelope are heated and sealed at a high temperature using a hot-melt adhesive, the vacuum vessel is By controlling the internal pressure, it is substantially possible to equalize the pressure inside and outside the envelope while flowing the inert gas inside the envelope. As a result, the pressure inside the envelope increases, and the low-melting glass that has been fluidized near the sealing temperature flows into the envelope without causing an accident that the inert gas breaks through and blows out to the outside. It is possible to increase the flow rate of the inert gas, and to suppress deterioration of the non-evaporable getter due to gas released from the members constituting the envelope into the envelope in a high-temperature state for sealing. Sufficient flow rate of the inert gas into the envelope.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be specifically described with reference to the drawings. First, FIG.
1 shows a configuration of an envelope of an image display device sealed by the present invention.
Here, the device electrode 8 is previously formed on the rear substrate 1, and a non-evaporable getter is provided on the wiring connected to the device electrode 8 by, for example, thermal spraying (not shown). ).

On the front substrate 2, a phosphor 6 and an anode electrode 7 are formed in advance. And the back substrate 1
The front substrate 2 is heated and sealed with low melting point glass (frit glass) 5 so as to sandwich the outer frame 3 and the two exhaust pipes 4.

FIG. 2 shows a configuration of a conventional sealing device for sealing the inside of the envelope shown in FIG. 1 while flowing an inert gas. Here, the rear substrate 1 and the front substrate 2 are fixed to a jig 11 and positioned in an in-plane direction. Thereafter, by sandwiching the hot plate 12 from above and below, an argon gas (Ar) is introduced from one of the exhaust pipes connected to the joint 13 and the hot plate is heated while exhausting from the other, thereby sealing the low-melting glass. Put on.

FIG. 3 shows a sealing device according to the invention. The above-described conventional sealing device is installed in a vacuum container 14. The vacuum vessel 14 is provided with an argon gas inlet 15 and a gas outlet 16. By adjusting the variable leak valves 17 and 18 attached to each of them and adjusting the pressure of the introduced argon gas, The pressure inside the vacuum vessel 14 can be adjusted.

In this embodiment, a pressure gauge cannot be directly attached to the envelope 10, and the pressure inside the envelope 10 cannot be measured directly. Was adjusted as follows. That is, the envelope 1
In the joint 13 for introducing argon gas into the inside,
The pressure gauge 19 and the flow meter 20 are attached. However, the two exhaust pipes 4 attached to the envelope 10 are the same as described above, and the pressure gauges are attached at symmetrical positions so that the conductance from the envelope 10 to the pressure gauge is equal. Have been.

At this time, if the pressure of the argon gas introduced into the envelope 10 is P1, the flow rate is Q1, and similarly, the pressure of the gas exiting the envelope 10 is P2, and the flow rate is Q2, the panel The internal pressure Pp is represented by the following equation.

Pp = P1−Q1 / C = P2 + Q2 / C (Equation 1) where C is the conductance of the pipe from the pressure gauge to the envelope 10.

Before the temperature of the hot plate 12 is low and the low-melting glass 5 is softened, there is a gap between the low-melting glass 5 and the rear substrate 1, the front substrate 2, and the outer frame 3, and argon Q1 and Q2 are not equal due to gas leakage. When the temperature of the hot plate 12 rises and reaches the softening point of the low-melting glass 5 and the low-melting glass 5 softens, there is no gap due to the pressing pressure, and Q1 = Q2. then,
According to (Equation 1), the pressure Pp inside the panel can be expressed by the following equation.

Pp = (P1 + P2) / 2 (Equation 2) Further, since the pressure of the gas generated from the members constituting the envelope 10 due to the rise in temperature is sufficiently smaller than P1, At a temperature equal to or higher than the softening point of the melting point glass 5, P1 is almost equal to P2. At this time, from (Equation 2), the pressure Pp inside the panel can be expressed by the following equation.

Pp = P1 = P2 (Equation 3) That is, after the temperature of the hot plate reaches the softening point of the low-melting glass, the pressure inside the envelope 10 is
It can be considered as the pressure of the argon gas introduced into the inside.

In this embodiment, the softening point is 410 ° C.
Was used. In addition, hot plate 12
Until the temperature reaches 400 ° C., the variable leak valve 18 of the gas discharge port 16 of the vacuum vessel 14 is opened,
When the argon gas was circulated and the temperature reached 400 ° C., the variable leak valve 18 was closed, and the indicated value of the pressure gauge 20 attached to the vacuum vessel 14 was changed to the pressure of the argon gas introduced into the envelope 10, that is, the pressure. The pressure was increased to a value equal to a total of 19 indicated values. Then, when the indicated value of the pressure gauge 20 became equal to the indicated value of the pressure gauge 19, the variable leak valve 17 of the gas inlet 15 was closed, and the inside of the vacuum vessel 14 was maintained at the same pressure as the inside of the panel.

[0025]

As described above, according to the present invention,
In an image display device equipped with a non-evaporable getter on a wiring connected to an element electrode in an envelope or in an image display area, high temperature without deteriorating the adsorption characteristics of the non-evaporable getter. It becomes possible to seal. In other words, even after the sealing step, the non-evaporable getter maintains the exhaust capability (adsorption capability), thereby causing deterioration and damage of the electron source due to local gas release from members constituting the envelope. Since emission can be reduced and the device can be prevented from being destroyed due to discharge, a stable, long-life, high-quality image display device can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of an envelope of an image display device sealed by the present invention.

FIG. 2 is a schematic diagram illustrating a configuration of a sealing device in a conventional method of manufacturing an image display device.

FIG. 3 is a schematic view showing a configuration of a sealing device in a method for manufacturing an image display device according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 back substrate 2 front substrate 3 outer frame 4 exhaust pipe 5 hot-melt adhesive (low-melting glass) 6 phosphor 7 anode electrode 8 element electrode 10 envelope 11 fixing jig 12 hot plate 13 joint 14 vacuum vessel 15 argon gas Inlet 16 Gas outlet 17, 18 Variable leak valve 19, 20 Pressure gauge 21 Flow meter

Claims (4)

[Claims] 1. A front substrate provided with electrodes and phosphors for displaying an image and a rear substrate provided with device electrodes for emitting electrons are arranged at a predetermined distance from each other, and an envelope is formed. And a non-evaporable getter arranged in the image display area of the envelope, and when manufacturing an image display device in which a plurality of members constituting the envelope are sealed, A method for manufacturing an image display device, comprising: installing an envelope in a vacuum vessel; and heating and sealing the envelope while independently controlling the pressure inside the envelope. 2. The method according to claim 1, wherein a predetermined flow rate of an inert gas is supplied to the inside of the envelope during the heating and sealing. . 3. When the envelope is installed in the vacuum container, the inside of the vacuum container is filled with an inert gas having a pressure equal to the inside of the envelope, and heating and sealing are performed. The method for manufacturing an image display device according to claim 1 or 2, wherein: 4. The image display area of the envelope in which the non-evaporable getter is arranged is on a wiring connected to the element electrode. A method for manufacturing an image display device.