JP3431583B2 - Image display device and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device using a cold cathode type electron-emitting device and a manufacturing method thereof.

[0002]

2. Description of the Related Art An image display device using cold cathode type electron emitting devices is a device for displaying an image by exciting and emitting a phosphor screen by electron beams emitted from a large number of electron emitting devices arranged in a matrix. Since it can be formed into a thin flat plate, the FPD (Flat Panel Disp1ay)
It has received a lot of attention as a display panel for TV. As a specific structure of this image display device, a vacuum envelope is composed of a glass rear substrate and a front substrate which are spaced apart and arranged substantially in parallel, and a large number of electron-emitting devices are formed on the inner surface of the rear substrate. The phosphor screens are arranged in a matrix and the phosphor screen is arranged on the inner surface of the front substrate. The back substrate and the front substrate face each other with a plate-shaped side wall arranged in the peripheral portion.

In manufacturing such an image display device, in order to maintain a high vacuum inside the vacuum envelope, an exhaust pipe is provided on the rear substrate, and a vacuum pump exhausts gas while baking. However, since the front substrate and the rear substrate are arranged close to each other, it is extremely difficult to evacuate to a high vacuum state in a short time. As a method of solving such a problem, while the front substrate and the rear substrate are sufficiently separated in a vacuum device, both substrates are baked and the entire vacuum device is evacuated to a high vacuum to reach a predetermined vacuum degree. In this case, there is a method of joining the front substrate and the rear substrate via the side wall. This method requires a joining / sealing material or joining technique that can be used even at a high temperature of 300 to 400 ° C. under high vacuum. For example, the bonding / sealing material should have sufficient bonding strength to bond the substrate to the side wall, the gas emission from the bonding / sealing material should be small at high temperature and high vacuum, and the bonding / sealing material should be sufficient for the substrate and the sidewall even at high temperature. Wettability is maintained,
It is required that the joint / seal material does not accumulate, and that the joint / seal material does not flow out of a predetermined position or spill over.

In general, metals such as indium and gallium are used for joining glass members or vacuum seals for which an organic joining / sealing material cannot be used.
This is because these metals exhibit wettability with glass when the temperature is raised above the melting point. A metal having a physical property such as mercury that can be repelled from the glass surface even if melted does not meet the requirements for joining glass members and vacuum sealing.

However, when a metal such as indium and gallium is used as a bonding and sealing material for bonding the back substrate and the front substrate to the side wall in the image display device as described above, it is much higher than its melting point as described above.
Since a heat treatment at a high temperature of 00 to 400 ° C. is imposed, the wettability of these metals with respect to glass is lowered, and there is a problem that a sufficient bonding or sealing effect cannot be exhibited.

[0006]

As described above, in the flat panel image display device using the cold cathode type electron-emitting device, the bonding / sealing material used for bonding between the glass substrate and the side wall and for vacuum sealing. Since the wettability with respect to glass is lowered by the high temperature heat treatment, there is a problem that sufficient bonding and vacuum sealing performance cannot be maintained and reliability is lowered.

An object of the present invention is to provide a highly reliable image display device which is excellent in bonding between a substrate and a side wall and in vacuum sealing performance, and a manufacturing method thereof.

[0008]

In order to solve the above-mentioned problems, the present invention provides a vacuum envelope composed of a rear substrate and a front substrate which are spaced apart and substantially parallel to each other, and are formed on an inner surface of the rear substrate. An electron display device having a plurality of electron-emitting devices and a phosphor screen which is formed on the inner surface of the front substrate and emits light when excited by an electron beam emitted from the electron-emitting devices. It is characterized in that the back substrate and the front substrate are joined via the alloy layer.

The vacuum envelope may further have a partition wall interposed between the back substrate and the front substrate, in which case at least one of the back substrate and the front substrate and the partition wall are made of an indium alloy. Joined by layers.

The indium alloy is obtained by adding at least one element selected from the group of silver, zinc, bismuth, tin, gallium, gold and copper to indium in addition to silver oxide, or in addition to silver oxide. More silver,
It may be an indium alloy in which at least one element selected from the group of copper, gold, aluminum and antimony is added to indium. That is, indium alloys include silver, zinc, copper, gold, bismuth, in addition to silver oxide,
It may be an indium alloy in which at least one element selected from the group of tin, gallium, aluminum and antimony is added to indium.

Silver, zinc, bismuth, tin, gallium, gold, copper and the like are elements having an effect of lowering the melting point below the melting point of indium by alloying with indium, and these elements are used for the purpose of such effect. When added to indium, the addition amount (when adding these elements in combination, the total addition amount) should be such that the temperature of the liquidus line from the eutectic point does not exceed the decomposition temperature of silver oxide. Is desirable.

On the other hand, silver, copper, gold, aluminum, antimony and the like are elements which have the effect of increasing the melting point of indium when added to indium, and these elements are suitable for indium alone or in combination. If added only in an amount, if it is kept at a high temperature in the subsequent heat treatment,
A region where two phases, a liquid phase and a solid phase, coexist is generated. In this sense, it is desirable that the heat treatment such as baking and bonding be performed at a temperature between the liquidus and solidus lines of the indium alloy. Therefore, when adding these elements to indium for the purpose of increasing the melting point as described above,
The addition amount (When adding these elements in combination,
It is desirable to select the total addition amount) so that the indium alloy enters between the liquidus line and the solidus line on the binary or multicomponent phase diagram at the temperature of the heat treatment.

Further, according to the present invention, in manufacturing such an image display device, indium alloy in which silver oxide is added to indium or silver oxide is added at a predetermined position on the inner surface of at least one of the back substrate and the front substrate. In addition to silver oxide, an indium alloy in which at least one element selected from the group of silver, zinc, copper, gold, bismuth, tin, gallium, aluminum and antimony is added to indium is placed at a predetermined temperature, for example, After melting the indium alloy by melting at 160 ° C., the back substrate and the back substrate are joined by the indium alloy through a baking step in a vacuum.

When the vacuum envelope further has a partition wall interposed between the rear substrate and the front substrate, the plate-shaped glass having substantially the same thermal expansion characteristics as at least one of the rear substrate and the front substrate as the partition wall. Using a member, one end of the plate-shaped glass member is previously integrated on one inner surface of the back substrate and the front substrate, and then an indium alloy is placed at a predetermined position on the other inner surface of the back substrate and the front substrate. Then, the other end of the plate glass is joined to the other inner surface of the back substrate and the front substrate. Here, it is desirable that the bonding be performed in a vacuum.

According to the present invention, at least an indium alloy obtained by adding silver oxide to indium, or at least one selected from the group consisting of silver, zinc, copper, gold, bismuth, tin, gallium, aluminum and antimony in addition to silver oxide. There is provided an indium alloy for joining, for vacuum sealing, or for joining and vacuum sealing, which is made of an indium alloy in which one element is added to indium.

In the above-mentioned indium alloy, the supply of oxygen plays an important role when the glass and the indium are wet, and when the molten indium is held at a high temperature, the wet surface is reduced by the surface tension. This was done with a focus on contraction, and it is possible to realize the supply of oxygen necessary for bonding and the suppression of contraction by silver oxide. Since this ensures sufficient wettability, the characteristics of using indium, which has wettability with respect to glass, as the main component of the joining / sealing member are fully utilized to realize high joining performance and vacuum sealing performance. be able to.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a schematic configuration of a flat panel image display device using a cold cathode type electron-emitting device according to an embodiment of the present invention. This image display device displays an image by exciting and emitting a phosphor screen 3 with an electron beam emitted from a large number of electron-emitting devices 2 in a vacuum envelope 1 which is configured as a flat plate as a whole. In more detail, it is configured as follows.

The vacuum envelope 1 is a glass container mainly composed of a glass rear substrate 4 and a front substrate 5 which are spaced apart and arranged substantially in parallel with each other, and between the rear substrate 4 and the front substrate 5. A plate-like side wall 6 made of glass is arranged at the peripheral edge of the. The plate-shaped partition wall 6 includes a rear substrate 4 and a front substrate 5.
It is desirable that the back substrate 4 and the front substrate 5 have different thermal expansion coefficients from each other, and the rear substrate 4 and the front substrate 5 have different thermal expansion coefficients. It is preferably formed by a glass member having a modulus. Further, a large number of spacers 7 for supporting the atmospheric pressure applied to the back substrate 4 and the front substrate 5 are arranged between the back substrate 4 and the front substrate 5.

The electron-emitting devices 2 are arranged in a matrix on the inner surface of the rear substrate 4 (the surface facing the front substrate 5). The electron-emitting device 2 is known as a cold-cathode type electron-emitting device. For example, it is continuous with both layers of an insulating layer made of a SiO ₂ film and a gate electrode layer made of a Mo film laminated on a Si single crystal substrate. Then, a large number of minute holes are formed in a matrix by etching, and a conical emitter made of, for example, Mo is formed in these holes. The electron-emitting device 2 is connected to a drive circuit via a matrix wiring (not shown), and is driven by the drive circuit in response to an image signal, so that the electron beam whose intensity is modulated in accordance with the image signal is used as a phosphor screen. Release towards 3.

The phosphor screen 3 is formed on the inner surface of the front substrate 5 (the surface facing the rear substrate 4) and is excited by the electron beam emitted from the electron-emitting device 2 to emit light. As a result, an image is emitted and displayed on the phosphor 3, and the user can see the displayed image through the front substrate 5. A metal back layer 8 is formed on the phosphor screen 3. When a full-color display device is configured as an image display device, the phosphor screen 3 is R
It is composed of (red), G (green), and B (blue) phosphor dots.

The inner surfaces of the back substrate 4 and the front substrate 5 and the plate-like side wall 6 are joined by a joining / sealing material 9 (indium alloy layer) made of an indium alloy according to the present invention,
In addition, the vacuum envelope 1 is vacuum-sealed. The indium alloy that serves as the bonding / sealing material 9 is selected from the group consisting of (a) indium alloy in which silver oxide is added to indium, (b) indium oxide and silver, zinc, bismuth, tin, gallium, gold and copper. An indium alloy in which at least one selected element is added, or (c) indium alloy in which silver oxide and at least one element selected from the group of silver, copper, gold, aluminum and antimony are added to indium is used. . By using such an indium alloy as the bonding / sealing material 9, the bonding performance and the vacuum sealing performance between the back substrate 4 and the front substrate 5 made of glass and the plate-like side wall 6 also made of glass are significantly improved. ,
It is possible to realize a highly reliable image display device.

The development process of the above-described indium alloy used as the joint / sealing material 9 will be described below. The inventors have spent a lot of time on elucidating the mechanism involved in the bonding of glass and metal in order to solve the problems when conventional metals such as indium and gallium are used for bonding glass members and as sealing materials, and Came to devise an indium alloy. The presence of oxygen seems to be large for indium to wet or bond with glass. Therefore, the supply of oxygen is essential, but the usual wetting or bonding is covered by oxygen existing on the glass surface or oxygen supplied from the atmosphere.

However, when the specifications for the high temperature heat treatment of the glass members to be joined become strict, it has been found that such existing oxygen alone is insufficient. Under the situation where indium and glass are bonded together with insufficient supply of oxygen, the force of releasing indium from the glass surface by the surface tension of the molten indium exceeds the bonding force between indium and the glass surface. As a result, the indium hemispheres corresponding to the surface tension remain on the surface of the glass member after the heat treatment, and they cannot form a continuum, so that the vacuum cannot be maintained.

In order to increase the bonding strength between indium and glass, the method of introducing oxygen into indium is a solution, but even if oxygen is simply put in indium,
The solubility of oxygen in indium is about 5 ppb even at 400 ° C. (CBA1ock et al. “Determination of O solubility in molten In by combination of Knuzen mass spectrometry and coulometric titration”, Journal of Japan Institute of Metals, Vo1.44, No. 11). (1980), pp.1239-1
Calculated from the formula in 243), it is not effective. Therefore, depending on how to supply oxygen to indium, the present inventors can supply oxygen by mixing a substance that releases oxygen at a temperature at which indium melts or by arranging it at the interface between glass and indium. From the idea that it can be obtained, it was found that silver oxide has excellent properties from among a myriad of chemical substances. Silver oxide is stable at room temperature, but when heated to 160 ° C. or higher, it is separated into metallic silver and oxygen by the reaction of Ag ₂ 0 → 2Ag + O ₂ even in the atmosphere. On the other hand, since the melting point of indium is 156 ° C., silver oxide is decomposed and oxygen is released when the indium is melted. By utilizing this oxygen, a strong bond between indium and glass can be obtained.

As described above, the indium alloy according to the present invention exhibits excellent characteristics due to the presence of silver oxide. However, in the production of such an indium alloy, silver oxide can be produced at 160 ° C. or higher. Decomposition and 1 indium
It is not easy because it melts at 57 ° C.

Generally, such a mixture of a metal and an oxide is obtained by introducing the oxide into a molten metal, but it is difficult to control because the difference between the decomposition temperature and the melting temperature is only 3 ° C. In addition, if there are restrictions on such dissolution,
Although the powder metallurgy method is adopted, since the recrystallization temperature of indium is extremely low, it is difficult to maintain the shape of the powder as a powder by a usual method, and thus the powder metallurgy method for obtaining a uniform dispersion cannot be established.

In order to solve these problems, the inventors have (1) lowered the melting temperature of indium to widen the difference from the decomposition temperature of silver oxide, and (2) a melting point at which indium can maintain its shape as a powder. A method of (3) forcibly mixing by a mechanical method was proposed, in which the powder is held and mixed at a temperature (absolute temperature) of 1/2 or less of the above. More specifically, with regard to the method (1), by forming a eutectic with indium such as silver, zinc, bismuth, tin, gallium, gold, and copper on indium,
That is, it can be realized by adding an element having an effect of lowering the melting point to below the melting point of indium by alloying.

With respect to the method (2), the powder shape can be maintained by maintaining the indium powder at an absolute temperature of 215 K or less from the time of production, and a usual powder metallurgical method can be used.

As for the method (3), silver oxide powder is disposed on the indium plate or sheet by spraying or coating, and two or more of these plates or sheets are stacked or one is folded and then rolled. Then, by repeating this operation, silver oxide can be uniformly dispersed in indium. After rolling, heat treatment at a temperature equal to or lower than the melting point of indium is also an effective treatment.

If an idea of mixing silver oxide with indium is developed, a method of spraying or applying silver oxide at a predetermined position at the time of manufacturing a glass part or arranging silver oxide around indium can be simplified. Is valid.

Further, as a factor that hinders the shape stability of the indium alloy on glass at high temperatures, the generation of shrinkage force due to the relationship between surface tension and viscosity can be mentioned. In order to lower the surface tension of indium, a method of adding another element can be considered, but there remain problems that the melting point changes depending on the addition amount and that the surface tension cannot be sufficiently reduced. .

The inventors have found that such a problem can be solved if the indium alloy can exist as a solid without being completely melted at a predetermined temperature. That is, by adding an element such as silver, copper, gold, aluminum, or antimony, which has the effect of increasing the melting point of indium to indium, and adjusting the addition amount appropriately, a liquid melted at a predetermined temperature can be obtained. It was found that a region where two phases, a phase and a solid phase, coexist was obtained, leading to the finding that the presence of the solid phase can suppress surface contraction due to surface tension.

Some examples of the method for producing an indium alloy according to the present invention based on the above knowledge will be described below. (Example 1) 0.38 g of silver oxide powder was sprayed on the surface of an indium sheet having a thickness of 1 mm, a width of 20 mm, and a length of 50 mm, and then stretched by folding and rolling at a half position in the length direction. After that, it was bent at a half position in the longitudinal direction and again stretched on a rolling mill. By repeating this process 10 times, it was possible to obtain an indium alloy in which silver oxide was almost uniformly dispersed. When a part of this indium alloy was taken and subjected to chemical analysis, it was found to be an indium alloy containing 5% by weight of silver oxide.

The indium alloy was welded to predetermined positions on two glass plates made of soda lime using an ultrasonic soldering iron heated to 200 ° C. At this time, the glass plate was arranged in a hot plate shape and heated to 250 ° C.

After heating these glass plates under a vacuum of 3 × 10 ⁻⁶ Pa at 400 ° C. for 1 hour, an appropriate amount of a spacer having a height of 500 μm is placed between the two glass plates while maintaining the temperature of 400 ° C. After being arranged, they were joined via the indium alloy portion.

A vacuum leak test of the space formed by this laminated glass plate was carried out at room temperature, and 1 × 10 ⁻⁹ atm · cc /
It was confirmed that it was less than sec and had a high vacuum holding capacity. In addition, when an indium alloy was taken out from this laminated glass plate and analyzed, it was found to be an indium alloy containing 4.6% by weight of silver, and even if silver oxide remained, it was in the ppm or ppb order, which was not sufficient for maintaining vacuum. Almost no inconvenient amount was present.
By increasing the heating time, it is possible to make the silver oxide in the indium alloy zero.

(Example 2) Alumina spheres, indium shot (teardrop-shaped particles) and a predetermined amount of silver oxide powder were put into an alumina pot, the pot was placed on a planetary ball mill, and the mill was operated for 8 hours. And forced mixing process was performed. A part of the obtained mixture was chemically analyzed and found to be an indium alloy containing 3% by weight of silver oxide.

Using this indium alloy, the same glass plate bonding and vacuum leak test as in Example 1 were carried out, and similar results were obtained. Moreover, when the indium alloy was taken out from the laminated glass plate and analyzed, silver was found to be 2.8.
It was an indium alloy containing 50% by weight, and the presence of silver oxide in an amount inconvenient for maintaining a vacuum was not found, as in Example 1.

Example 3 45 g of an indium alloy containing 3% by weight of silver was melted at 145 ° C., 5 g of silver oxide powder was added to the molten indium alloy, and the mixture was poured into a mold with sufficient stirring to obtain silver oxide. A dispersed indium alloy was obtained. When a part of the obtained mixture was chemically analyzed, silver oxide was found to be 10
It was an indium alloy containing wt%.

An ultrasonic soldering iron heated to 250 ° C. was used at a predetermined position of the plate-shaped lid member made of soda-lime glass and the plate-shaped lid member made of soda-lime glass, using this indium alloy. And heat it under a vacuum of 3 × 10 ⁻⁶ Pa for 1 hour at 450 ° C., and while maintaining this temperature, a glass plate-shaped member made of glass and a flat plate-shaped lid member having a height of 1 mm An appropriate amount of spacers were arranged and joined via the indium alloy portion.

A vacuum leak test of the space formed between the glass dish-shaped member and the flat plate-shaped lid member was conducted at room temperature.
It was 1 × 10 ⁻⁹ atm · cc / sec or less, and it was confirmed to have a high vacuum holding capacity. Furthermore, when an indium alloy was taken out from the glass member and analyzed, it was an indium alloy containing 10% by weight of silver, and it was not recognized that silver oxide was present in an amount inconvenient for maintaining a vacuum. .

(Embodiment 4) A square plate of silver oxide was screen-printed with indium alloy at a predetermined position on a plate-shaped (depth 1 mm) member made of soda lime glass and a flat plate-shaped lid member also made of soda lime glass. After applying 2 mg per cm, welding with an ultrasonic soldering iron heated to 250 ° C. while filling indium on this, heating at 450 ° C. for 1 hour under a vacuum of 3 × 10 ⁻⁶ Pa, and then at this temperature While holding the above, an appropriate amount of a spacer having a height of 1 mm was arranged between the glass dish-shaped member and the flat plate-shaped lid member, and the glass plate-shaped member and the flat plate-shaped lid member were bonded via the indium alloy portion.

A vacuum leak test of the space formed between the glass dish-shaped member and the flat plate-shaped lid member was conducted at room temperature.
It was 1 × 10 ⁻⁹ atm · cc / sec or less, and it was found to have a high vacuum holding capacity.

(Embodiment 5) A silica glass dish-shaped plate (depth: 1 m) placed on a hot plate heated to 250 ° C.
m) member and a plate-like lid member also made of silica glass at a predetermined position with an indium ribbon having a thickness of 0.1 mm coated with 2 mg of silver oxide per square cm, and 250
Welding was performed using an ultrasonic soldering iron heated to about ℃. The glass plate-shaped member and the flat plate-shaped lid member were bonded under the same conditions as in Example 4, and a vacuum leak test was carried out. The result was 1 × 10 ⁻⁹ atm · cc / sec or less, and a high vacuum holding capacity was obtained. It turned out to have.

(Embodiment 6) A soda lime glass plate-shaped (depth 1 mm) member placed on a hot plate heated to 300 ° C. and a soda lime glass flat plate lid member were also placed at predetermined positions. A ribbon of 25 wt% silver-indium alloy having a thickness of 0.1 mm coated with 2 mg of silver oxide per 1 cm 2 was filled and welded using an ultrasonic soldering iron heated to about 300 ° C. The glass dish-shaped member and the flat plate-shaped lid member are ^heated to 300 ° C. under a vacuum of 3 × 10 ⁻⁶ Pa.
-Heated for 1 hour. At this time, the indium alloy melts on the glass surface, but the melt does not shrink due to surface tension,
The initial shape was retained. After the heat treatment, while maintaining this temperature, a proper amount of a spacer having a height of 1 mm was arranged between the glass dish-shaped member and the flat plate-shaped lid member, and the glass plate-shaped member and the flat plate-shaped lid member were bonded via the indium alloy portion. When the vacuum leak test of the space formed between the glass plate-shaped member and the flat plate-shaped lid member was performed at room temperature, it was 1 × 10 ⁻⁹ atm · cc / sec or less, and had a high vacuum holding capacity. I found out that

When the silver oxide-added indium alloy was prepared by the melting method, silver was mentioned in the above-mentioned examples, but it is assumed that the melting point thereof becomes lower than that of indium by forming a eutectic with indium. In addition, zinc, bismuth, tin,
Gallium, gold, copper, etc. are effective. In addition to silver, metals such as copper, gold, aluminum, and antimony are effective as the additive metal for indium that realizes a solid-liquid two-phase that exhibits the effect of maintaining the shape during heat treatment at high temperature. Example 1
As shown in FIGS. 6 to 6, silver oxide is effective by applying or spraying it on the glass surface or the indium surface, but the same effect can be obtained by sandwiching it between the indium sheets.

Next, among the manufacturing steps of the image display device according to the present embodiment, the steps particularly related to the present invention will be described. A rear substrate 4 having an electron-emitting device 2 formed on its inner surface,
The front substrate 5 having the phosphor screen 3 and the metal back layer 8 formed on the inner surface is opposed to each other with the plate-shaped side wall 6 and the spacer 7 interposed therebetween, and the back substrate 4, the front substrate 5 and the plate-shaped side wall 6 are provided.
The vacuum envelope 1 is constituted by the following. In this case, the back substrate 4 and the front substrate 5 and the plate-like side wall 6 are joined by the joining / sealing material 9 made of an indium alloy and, at the same time, vacuum sealing is performed.

In an actual process, the back substrate 4 and the front substrate 5 are sufficiently separated in a vacuum device (not shown),
These back substrate 4 and front substrate 5 are, for example, 300 to 4
While baking at a temperature of about 00 ° C., the entire inside of the vacuum device is evacuated to a high vacuum. Then, when a predetermined degree of vacuum is reached, the back substrate 4 and the front substrate 5 are opposed to each other with the plate-shaped side wall 6 interposed therebetween, and the bonding / sealing material 9 is attached to the back substrate 4.
Also, the back substrate 4 and the front substrate 5 are mounted on the inner surface of the front substrate 5 at a position facing the plate-shaped side wall 6 and heated to a temperature of, for example, 160 ° C. or higher to melt the back substrate 4 and the front substrate. 5 and the plate-like side wall 6 are joined and vacuum sealed.

The bonding / sealing material 9 has sufficient bonding strength for bonding to the back substrate 4, the front substrate 5 and the plate-shaped partition wall 6, and also has a bonding strength from the bonding / sealing material 9 even at high temperature and high vacuum. Of the gas is small, sufficient wettability is maintained with respect to the rear substrate 4 and the front substrate 5 even at high temperatures, and the pool of the joint / seal material 9 and the flow of the joint / seal material 9 flow from a predetermined position. It is required that it does not overflow or spill.

Here, if the joining / sealing material 9 is formed of an indium alloy in which silver oxide is added to indium as described above, the above-mentioned requirements for the joining / sealing material 9 can be sufficiently satisfied from the above experimental results. . Therefore,
By using such a joint / seal material 9, an image display device having high reliability can be obtained by efficiently using a simple structure and a simple manufacturing process, and by having excellent joining and vacuum sealing performance of the vacuum envelope 1. It becomes possible to manufacture, and its industrial effect is extremely high.

As an element to be added to indium, the melting point is raised by the addition to indium to obtain 300 to 40
In addition to silver, metal elements such as copper, gold, aluminum, and antimony can be used as long as they can realize an indium alloy that realizes a solid-liquid two-phase that maintains the shape during heat treatment at a high temperature of 0 ° C. It is valid. It goes without saying that two or more elements selected from the group consisting of silver, copper, gold, aluminum and antimony may be combined and added to indium. Furthermore, the addition amounts of these elements are determined depending on the heat treatment step to be performed, and are selected so that the liquidus of the indium alloy has a composition higher than the heat treatment temperature. In other words, it is desirable that the heat treatment at the time of baking and joining is performed at a temperature between the liquidus line and the solidus line of the indium alloy.

The present invention is not limited to the above embodiment, but can be implemented with various modifications. For example, in the image display device of the above-described embodiment, as described with reference to FIG. 1, the inner surface of the rear substrate 4 and the plate-shaped partition wall 6 and the inner surface of the front substrate 5 and the plate-shaped side wall 6 are joined and sealed with an indium alloy. Although the material 9 is used for joining, the invention is not limited to this.

For example, as shown in FIG. 2, the back substrate 4 and the plate-shaped side wall 6 are integrally formed in advance by integral molding or bonding, and the inner surface of the front substrate 5 and the plate-shaped side wall 6 are bonded and sealed by the sealing material 9. You may make it join, and conversely, FIG.
As shown in FIG. 5, the front substrate 5 and the plate-shaped side wall 6 may be integrally formed in advance by integrally molding or bonding, and the inner surface of the back substrate 4 and the plate-shaped side wall 6 may be bonded by the bonding and sealing material 9. .

Further, in the above embodiment, the case where the indium alloy is used as the joining and sealing member 9 has been described, but it is also possible to use it as a member only for joining or only for vacuum sealing. Further, although the partition wall 6 is interposed between the rear substrate 4 and the front substrate 5 in the above-described embodiment, both substrates may be directly bonded and vacuum-sealed with an indium alloy without interposing such a partition wall. .

The application of the indium alloy is not limited to the image display device using the above-mentioned cold cathode type electron-emitting device, and it is possible to join glass members or glass members to each other, or to bond these members. It can be widely applied to vacuum seals. The present invention can also be implemented as a glass component using an indium alloy as a joining member, a vacuum sealing member, or a joining / sealing member. The preferred embodiments of the present invention that are not limited to image display devices are listed below.

(1) An indium alloy characterized in that silver oxide is added to indium.

(2) Silver oxide and at least one element selected from the group consisting of silver, zinc, bismuth, tin, gallium, gold and copper (the effect of lowering the melting point below the melting point of indium by alloying with indium) Element with
Is an indium alloy having a composition near the eutectic point.

(3) Indium, silver oxide, and silver, copper,
An indium alloy comprising at least one element selected from gold, aluminum and antimony (element having an effect of increasing melting point by addition to indium).

(4) The indium alloy for bonding, for vacuum sealing, or for bonding and vacuum sealing according to any one of (1) to (3).

(5) A glass part bonded, vacuum sealed, or bonded and vacuum sealed with the indium alloy according to any one of (1) to (3).

(6) A predetermined amount of indium powder and silver oxide powder are mixed, and the mixture is pressure-molded and then sintered at a temperature of 160 ° C. or lower, or the mixture is hot at a temperature of 160 ° C. or lower. A method for producing an indium alloy, which comprises press forming. By this manufacturing method, the indium alloy described in (1) is obtained.

(7) The method for producing an indium alloy according to (6), wherein the step of mixing the indium powder and the silver oxide powder is carried out at a temperature below 55 ° C. below freezing.

(8) A predetermined amount of silver oxide is adhered (sprayed or applied) to an indium plate, and the indium plate is folded or laminated and repeatedly rolled at a temperature of 160 ° C. or lower to obtain a medium of indium. A method for producing an indium alloy, characterized in that silver oxide is dispersed in. The indium alloy described in (1) can also be obtained by this manufacturing method.

(10) Indium powder and silver oxide powder,
Powder of at least one element selected from the group of silver, copper, gold, aluminum and antimony is added, and a mixture of these powders is pressure-molded and then sintered at a temperature of 160 ° C. or lower, or the mixture is formed. Is subjected to hot pressing at a temperature of 160 ° C. or less to form an indium alloy. By this manufacturing method, the indium alloy described in (3) can be obtained.

(11) Arbitrary shape (grain, rod, plate, wire, strip,
(Powder or the like) and indium and silver oxide are put in a predetermined container, and the mixture is forcibly stirred at a temperature equal to or lower than the melting point of indium. The indium alloy described in (1) can also be obtained by this manufacturing method.

(12) After arranging silver oxide (by a method such as spraying or coating) on a predetermined position of the glass member, indium or the indium alloy of (4) is melted at a temperature of 160 ° C. or higher to obtain glass. A method for manufacturing a glass component, which comprises bonding indium or an indium alloy onto a manufacturing member, and bonding or vacuum sealing via the indium or indium alloy.

(13) Indium or indium on the glass member is melted at a temperature of 160 ° C. or higher by melting indium in which silver oxide is placed (by a method such as spraying or coating) at a predetermined position on the glass member. A method for manufacturing a glass component, which comprises joining alloys and performing joining or vacuum sealing via the indium or indium alloy.

[0068]

As described above, according to the present invention, it becomes possible to join and vacuum seal a glass vacuum envelope that requires a high vacuum and requires a high temperature heat treatment step during manufacturing. It is possible to provide an image display device suitable as an FPD panel using a cold cathode type electron-emitting device, which was difficult to realize.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of an image display device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a schematic configuration of an image display device according to another embodiment of the present invention.

FIG. 3 is a sectional view showing a schematic configuration of an image display device according to another embodiment of the present invention.

[Explanation of symbols]

1 ... Vacuum envelope 2 ... Electron emitting device 3 ... Phosphor screen 4 ... Rear substrate 5 ... Front substrate 6 ... Side wall 7 ... Spacer 8 ... Metal back layer 9 ... Bonding and sealing material

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akiyoshi Yamada 1-9-2 Harara-cho, Fukaya City, Saitama Prefecture, Fukaya Plant, Toshiba Corporation (56) Reference JP-A-11-233003 (JP, A) Kaihei 9-171768 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01J 31/12 H01J 9/26 H01J 29/86

Claims (5)

(57) [Claims] 1. A vacuum envelope comprising a rear substrate and a front substrate made of glass, which are spaced apart and arranged substantially parallel to each other, a plurality of electron-emitting devices arranged and formed on an inner surface of the rear substrate, and the front face. A phosphor screen that is formed on the inner surface of the substrate and that is excited by an electron beam emitted from the electron-emitting device to emit light, and the back substrate and the front substrate include an indium alloy layer containing a trace amount of silver oxide. An image display device, characterized in that the image display device is joined via the above. 2. The vacuum envelope further comprises a partition interposed between the back substrate and the front substrate, and at least one of the back substrate and the front substrate and the partition is the indium alloy layer. The image display device according to claim 1, wherein the image display device and the image display device are joined together. 3. The indium alloy further comprises silver, zinc,
The image display device according to claim 1 or 2, wherein the image display device contains at least one element selected from the group consisting of copper, gold, bismuth, tin, gallium, aluminum and antimony. 4. A vacuum envelope composed of a glass rear substrate and a front substrate which are spaced apart and arranged substantially in parallel with each other, and a plurality of electron-emitting devices arranged on an inner surface of the rear substrate.
In a method for manufacturing an image display device, which is formed on the inner surface of the front substrate and has a phosphor screen which is excited by an electron beam emitted from the electron-emitting device to emit light, at least one of the back substrate and the front substrate The indium alloy in which silver oxide is added to indium is placed at a predetermined position on the inner surface, and the indium alloy is welded by melting at a predetermined temperature, and then the back surface is formed by the indium alloy through a baking process in a vacuum. A method of manufacturing an image display device, which comprises bonding a substrate and the back substrate. 5. The vacuum envelope includes the rear substrate and a front substrate.
A plate-shaped glass member having a partition wall interposed between the plate and the plate-shaped glass member having substantially the same thermal expansion characteristics as at least one of the back substrate and the front substrate is used as the partition wall. It is integrated on one inner surface of the back substrate and the front substrate, and then the indium alloy is placed at a predetermined position on the other inner surface of the back substrate and the front substrate,
The method for manufacturing an image display device according to claim 4 , wherein the plate glass is bonded to the other inner surface of the back substrate and the front substrate.