WO2007080770A1

WO2007080770A1 - Image display

Info

Publication number: WO2007080770A1
Application number: PCT/JP2006/325640
Authority: WO
Inventors: Yuusuke Kasahara; Hiromitsu Takeda; Hiromichi Horie
Original assignee: Kabushiki Kaisha Toshiba; Toshiba Materials Co., Ltd.
Priority date: 2006-01-12
Filing date: 2006-12-22
Publication date: 2007-07-19

Abstract

A field emission display comprises a front plate having many phosphor layers and a back plate having many electron emitters, and the peripheral portions of these plates are bonded together and the inside thereof is evacuated. A non-evaporable getter member (22) for adsorbing a gas is formed on the surface of a metal back (20) of a phosphor screen which is provided on the inner surface of the front plate. The non-evaporable getter member (22) is composed of a fine powder (22a) of a non-evaporable getter and an inorganic binder (22b), and has a network structure by drying and fixing the inorganic binder (22b).

Description

Specification

Image display device

Technical field

[0001] The present invention relates to an image display device in which a non-evaporable getter member is disposed inside a vacuum envelope.

Background art

In recent years, various flat-type image display devices have attracted attention as next-generation lightweight and thin display devices that replace cathode ray tubes (hereinafter referred to as CRTs). For example, a plasma display (PDP) using phosphor emission due to a discharge phenomenon and a field “emission” display (hereinafter referred to as FED) mainly using electron emission by an electric field are known.

[0003] These image display devices include, as a basic configuration, a front substrate and a rear substrate that are arranged to face each other at a predetermined interval, and these substrates have an envelope by bonding their peripheral portions to each other. It is composed. In particular, the FED enables good image display by maintaining a high degree of vacuum in the space between the front substrate and the back substrate, that is, the inside of the envelope. In addition, the PDP makes it possible to display a good image by keeping the inert gas filling the inside of the envelope at a high purity.

[0004] For example, in the FED, in order to maintain a high vacuum in the envelope for a long period of time, a getter material for adsorbing the released gas is provided in the envelope. Conventionally, in order to improve the gas adsorption characteristics of the getter material, the getter material is deposited on the inner surface of the front substrate or the rear substrate or other structure in a vacuum processing apparatus, and both the substrates are sealed in a vacuum and surrounded. A method of forming a vessel has been proposed (see, for example, JP-A-2001-229824;).

[0005] However, such a method requires a vacuum chamber maintained at a high vacuum, which places a heavy load on the process. In addition, if the getter material is overlaid on the phosphor screen of the front substrate, the brightness is lowered. Or, if a getter material is stacked on the electron-emitting devices and wirings on the back substrate, the breakdown voltage deteriorates and the wirings are short-circuited.

In addition to this, a getter chamber is attached to the outer periphery of the envelope, and a non-evaporable getter is disposed inside the getter chamber. A method of activating a getter material by arranging a getter or an evaporative getter has also been proposed, but this method limits the location of the getter material. For this reason, when this method is applied to a relatively large image display apparatus, pressure distribution is generated in the display screen, and good display characteristics cannot be obtained.

[0007] In order to compensate for these drawbacks, in recent years, a method has been considered in which a non-evaporable getter (NEG) is pasted and formed at an effective location by coating. When NEG is pasted, a high molecular weight organic binder such as PV A and a solvent are required, but when NEG is activated in the heating process at 350 ° C to 500 ° C after coating film formation, The problem is that complete decomposition of the binder is difficult and the performance of NEG is greatly reduced. For this reason, this method can be used as an effective means.

Disclosure of the invention

An object of the present invention is to provide an image display device that can effectively function a non-evaporable getter without using an expensive vacuum device and can maintain good display performance for a long period of time. It is in.

In order to achieve the above object, an image display device of the present invention includes a vacuum envelope in which peripheral portions are sealed with a front substrate and a rear substrate facing each other and the inside is evacuated, and the front substrate A phosphor screen provided on the inside of the plate and having a large number of phosphor layers and a black light-shielding layer partitioning these phosphor layers, and provided on the inside of the back substrate, emits electrons toward the phosphor layer. A plurality of electron-emitting devices; and a non-evaporable getter member disposed inside the vacuum envelope and having a non-evaporable getter powder and an inorganic binder.

[0010] According to the above invention, the non-evaporable getter member provided inside the vacuum envelope is dried and the inorganic binder is fixed, so that the inorganic binder has a porous network structure. The exposed surface area where the type getter can be in direct contact with the atmosphere in the vacuum envelope is relatively large, and the non-evaporable getter can function effectively.

Brief Description of Drawings

FIG. 1 is an external perspective view showing an FED vacuum envelope according to an embodiment of the present invention. [FIG. 2] FIG. 2 is a partial cross-sectional view of the vacuum envelope of FIG. 1 taken along line II II.

FIG. 3 is a plan view showing a state in which a non-evaporable getter member is patterned on the FED phosphor screen of FIGS.

FIG. 4 is a partially enlarged cross-sectional view schematically showing a mesh structure of the non-evaporable getter member of FIG.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an image display apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. Here, as an example of an image display device, an FED equipped with a surface conduction electron-emitting device will be described.

[0013] As shown in FIG. 1 and FIG. 2, the FED includes a front substrate 11 and a rear substrate 12 each having a rectangular glass plate force as insulating substrates, and these substrates have a gap of 1 to 3 [mm]. They are placed opposite each other. The front substrate 11 and the back substrate 12 constitute a flat rectangular vacuum envelope 10 whose peripheral portions are bonded to each other via a rectangular frame-shaped side wall 13 and the inside is maintained in a vacuum state. Speak.

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 can be used.

[0015] On the inner surface of the front substrate 11, as shown in FIG. 3, phosphor layers of red (R), green (G), and blue (B)

A phosphor screen 15 having 16 and a black light shielding layer 17 formed in a matrix is formed. These phosphor layers 16 may be formed in stripes or dots. On the phosphor screen 15, a metal back 20 having an aluminum film equal force is formed.

In addition, a non-evaporable getter member 22 in which a non-evaporable getter (hereinafter referred to as NEG) and an inorganic binder are mixed is put on the surface of the metal back 20. As shown in FIG. 3, the non-evaporable getter member 22 may be provided only in a region overlapping the black light shielding layer 17, but the corresponding electron-emitting device may be provided even in a region overlapping the phosphor layer 16. If the electron beam from 18 hits, it is okay if it is in the area. The non-evaporable getter member 22 will be described in detail later. [0017] On the inner surface of the back substrate 12, a large number of surface-conduction electron-emitting devices 18 each emitting an electron beam are provided as electron sources for exciting the phosphor layer 16 of the phosphor screen 15. . These electron-emitting devices 18 are arranged in a plurality of columns and a plurality of rows corresponding to each pixel. Each 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 driving the electron-emitting devices 18 are provided on the inner surface of the rear substrate 12 in a matrix shape, and the ends thereof are drawn out of the vacuum envelope 10.

In the FED having the above structure, when an image is displayed, an anode voltage is applied to the phosphor screen 15 and the metal back 20, and the electron beam emitted from the electron-emitting device 18 is accelerated by the anode voltage to phosphor. Collide with the screen. As a result, the phosphor layer 16 of the phosphor screen 15 is excited to emit light and display a color image.

Next, the physical properties of the non-evaporable getter member 22 according to the present embodiment will be described in detail, and a method for manufacturing the FED having the above structure will be briefly described.

[0020] As described above, the non-evaporable getter member 22 of the present embodiment is formed by mixing NEG and an inorganic binder. In the present embodiment, a mixture containing Zr, V, and Fe in a ratio of 7: 2: 1 is melted by arc melting to produce an ingot, and this ingot is pulverized by an average particle size of 10 [m The NEG fine powder was manufactured by pulverizing to a degree. As an inorganic binder, colloidal silica containing about 15% by weight of silica particles having an average particle size of about 10 [nm] is prepared, and the NEG fine powder produced as described above and the colloidal silica in a weight ratio. 5: 2 was mixed to produce a non-evaporable getter member 22 paste.

[0021] The particle size of the above-mentioned NEG fine powder is desirably 200 [m] or less. That is, if the particle size is large, it is difficult to obtain an adhesive force, and the adsorption efficiency per unit weight is also deteriorated, resulting in poor efficiency. The inorganic binder is not limited to the colloidal silica used in this embodiment as long as it is an aqueous inorganic binder, but is not limited to colloidal solution such as colloidal alumina using oxide fine particles, sodium-based water glass, potassium A system water glass or a mixture thereof can be used. Further, the mixing ratio of the inorganic binder to the fine powder of NEG is appropriately selected depending on, for example, the paste application method, which is desirably the minimum amount capable of obtaining sufficient adhesive strength. In the present embodiment, before the front substrate 11 and the rear substrate 12 are bonded, the paste of the non-evaporable getter member 22 manufactured as described above is screen-printed by black printing as shown in FIG. I put it on 17 and put it on the surface of the metal back 20. Then, the patterned non-evaporable getter member 22 was heated at a temperature of about 100 [° C.] and dried to be fixed. Fig. 4 shows an image of NEG22a and inorganic binder 22b at this time. In the present embodiment, the film thickness of the non-evaporable getter member 22 is set to about 30 [m].

[0023] As shown in FIG. 4, after applying the non-evaporable getter member 22 to the surface of the metal back 20, when the inorganic binder is dried, the inorganic binder 22b becomes a porous network structure, and the NEG fine powders 22a The surface of the NEG fine powder 22a can be exposed with a relatively large surface area. The network structure of such an inorganic binder allows the NEG fine powder 22a to be activated in the subsequent activation process, and then the area where the surface of the NEG is exposed can be made relatively large so that the NEG functions sufficiently. it can.

[0024] In the present embodiment, as described above, the force by which the non-evaporable getter member 22 is put on the surface of the metal back 20 by screen printing is not limited to this, but the ink jet system, the dispenser coating system, Other application methods such as spray coating and electrostatic coating may be used. Further, in the present embodiment, it is more preferable that the force film thickness when the film thickness of the non-evaporable getter member 22 is set to 30 [; zm] is set to about 1 to 500 [/ ζ πι]. It is desirable to set it to about 10 to 100 [μm].

[0025] That is, if the film thickness of the non-evaporable getter member 22 is thinner than 1 [m], the gas adsorbing ability after activating NEG becomes insufficient as described later, and the film thickness becomes 500 [; zm. ], The non-evaporable getter member 22 is easily peeled off. In particular, if the film thickness force of the non-evaporable getter member 22 is OO [m] or less, there is almost no fear of peeling, and if it is 10 [μm] or more, the gas adsorption capacity is sufficiently satisfactory. This preferable numerical range of the film thickness is due to the porous structure when the non-evaporable getter member 22 of the present embodiment is dried and fixed.

[0026] After the non-evaporable getter member 22 is formed on the surface of the metal back 20 as described above, the peripheral portions of the front substrate 11 and the rear substrate 12 are sealed. At this time, the best characteristics can be obtained by arranging the front substrate 11 and the rear substrate 12 in the vacuum chamber and sealing the peripheral edges. The power to be able to manufacture It is necessary to prepare a large vacuum chamber, which increases the manufacturing cost.

. For this reason, in this embodiment, the front substrate 11 and the rear substrate 12 are placed in a baking furnace (not shown) with the front substrate 11 and the rear substrate 12 facing each other with a certain gap, and sealing is applied to the inner surface of the peripheral portion in advance. The material was melted to seal the peripheral portions of the substrates.

In the present embodiment, the side wall 13 is bonded in advance to the inner peripheral edge of the back substrate 12, and the sealing material is applied in advance to the end surface of the side wall 13 facing the front substrate 11. In addition, a sealing material was applied in advance to a position where the inner peripheral edge of the front substrate 11 was opposed. As the sealing material, it is desirable to use a low melting point glass having a softening temperature of about 350 to 500 [° C]. In other words, if the melting temperature (sealing temperature) of the sealing material is too high, the electron-emitting device 18 provided on the rear substrate 12 will be damaged, and if the sealing temperature is too low, baking after sealing will not be performed. The evaporative getter cannot be fully activated. In order to reduce damage to the electron-emitting device 18, it is desirable to perform sealing in an inert atmosphere or a reducing atmosphere, but it is also possible to select an atmosphere depending on time and temperature.

[0028] After sealing the peripheral portions of the substrates 11 and 12, the inside of the vacuum envelope 10 is exhausted through an exhaust pipe (not shown). At the same time, the non-evaporable getter member 22 provided inside the front substrate 11 is activated. At this time, when the degree of vacuum inside the vacuum envelope 10 becomes 1 × 10 ” ³ [Pa] or less, the substrates 11 and 12 are heated to about 350 to 500 [° C.] to obtain a non-evaporated gate. Activate the data.

[0029] As described above, according to the present embodiment, an FED capable of maintaining high display performance over a long period of time can be obtained without using an expensive vacuum apparatus. In addition, when the substrates 11 and 12 are heated to a high temperature in the activation process described above, there is no concern about the generation of organic gas as in the case of using an organic binder, and there is no concern about the generation of organic gas when using FED. The vacuum degree of the vacuum envelope 10 can be maintained over a long period of time.

It should be noted that the present invention is not limited to the above-described embodiment, and can be embodied by modifying the constituent elements without departing from the scope in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, the constituent elements over different embodiments may be appropriately combined. [0031] For example, the dimensions, materials, and the like of each component can be variously selected as needed without being limited to the numerical values and materials exemplified in the above-described embodiment. The getter member is not limited to NEG such as Zr, V, and Fe used in the above-described embodiment, and other metal materials, organic materials, inorganic materials, and the like can be selected. For example, as NEG, metals such as Ti, Zr, V, Fe, Al, Cr, Nb, Ta, W, Mo, Th, Ni, and Mn, or alloys thereof may be used.

In the above-described embodiment, the case where the non-evaporable getter member 22 is provided on the surface of the metal back 20 has been described. However, the position where the getter member is provided is not limited to the front substrate 11 side, and the vacuum envelope is provided. You may form a getter member in the other structural member located in the inside. For example, when the non-evaporable getter member 22 is provided on the structure on the back substrate 12 side, the wiring 21 may be formed at a position that is not short-circuited at a position away from the electron-emitting device 18.

In the above-described embodiment, the case where the present invention is applied to the FED as the image display device has been described. However, the present invention is not limited to the FED, and is applied to other image display devices such as a PDP. Monkey.

Industrial applicability

[0034] Since the image display device of the present invention has the configuration and operation as described above, a non-evaporable getter without using an expensive vacuum device can be effectively functioned, and a good display can be obtained. Performance can be maintained over a long period of time.

Claims

The scope of the claims

[1] A vacuum envelope in which the front substrate and the rear substrate are opposed to each other, the peripheral portions are sealed together, and the inside is evacuated,

A phosphor screen provided on the inner side of the front substrate and having a number of phosphor layers and a black light shielding layer partitioning these phosphor layers;

A plurality of electron-emitting devices that are provided inside the back substrate and emit electrons toward the phosphor layer;

A non-evaporable getter member disposed inside the vacuum envelope and having a non-evaporable getter powder and an inorganic binder;

An image display device comprising:

[2] The image display device according to [1], wherein the non-evaporable getter member is provided in a region where the electrons do not hit the phosphor screen.

[3] The image display device according to claim 1, wherein the non-evaporable getter powder has a particle size of 200 [zm] or less.

[4] The image display device according to [1], wherein the inorganic binder is colloidal silica, colloidal alumina, water glass, or a mixture thereof.

[5] The image according to claim 2 or 4, wherein the evaporable getter member has a film thickness of 1 to 500 [m], preferably 10 to 100 [m]. Display device

6. The image display device according to claim 5, wherein the non-evaporable getter member is formed by screen printing, an inkjet method, a dispenser coating method, spray coating, or electrostatic coating.

[7] The structure according to any one of claims 1 to 6, wherein the inorganic binder has a porous structure that exposes the surfaces of the particles of the non-evaporable getter in a state of being dried and fixed. The image display device according to item 1.

[8] The non-evaporable getter is made of one or more metals of Ti, Zr, V, Fe, Al, Cr, Nb, Ta, W, Mo, Th, Ni, or Mn, or two or more alloys. The image display device according to claim 1, wherein the image display device includes the image display device.