JP2001266768A - Surface emission plate, method of producing plane luminescent plate, flat crt display, and field emission display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface emission plate, having a high extraction rate for extracting light to the outside and high surface brightness. SOLUTION: The plane luminescent plate comprises an electrode 2, formed on a glass plate 1 and a luminous layer 3 formed thereon for emitting a light with the radiation of an electron beam. An aerogel thin film 4 is provided between the glass plate 1 and the emission layer 3. The light emitted by the emission layer 3 is irradiated through the aerogel thin film 4, having a small refraction factor into the glass plate 1 and emitted from the surface of the glass plate 1, while reducing the loss of a wave light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat light-emitting plate, a method for manufacturing a flat light-emitting plate, a flat-panel CRT display using the flat light-emitting plate, and a field emission display.

[0002]

2. Description of the Related Art In recent years, various displays have been developed with the progress of the information-oriented society. Among them, flat displays such as a flat-panel CRT display and a field emission display have been receiving attention.
The flat light-emitting plate used for the light-emitting surface of such a flat-panel CRT display or field emission display is formed, for example, in a configuration as shown in FIG.

That is, the flat light emitting plate A shown in FIG. 5 is formed by laminating a transparent electrode 2 on one surface of a glass plate 1 and further laminating a light emitting layer 3 made of a phosphor on the surface of the electrode 2. It is. When the flat light-emitting plate A is disposed so as to face the electron beam source 5, a voltage is applied between the electrode 2 and the electron beam source 5, and an electron beam is emitted from the electron beam source 5.
The electron beam is drawn by the electrode 2 serving as the anode electrode, and the light emitting layer 3
And the light-emitting layer 3 emits light by excitation with an electron beam. The light emitted from the light-emitting layer 3 is emitted from the surface of the glass plate 1 through the electrode 2 so that the function as a display is exhibited.

Here, the extraction rate η at which light generated inside the flat light emitting plate A is extracted from the surface of the flat light emitting plate A to the outside is determined according to the law of classical optics from a medium having a refractive index n of 1. 0 is determined by the critical angle θc of total reflection when emitted into the air of 0. From the law of refraction, this critical angle θc is given by the following equation (1).

Sin θc = 1 / n (1) The extraction rate η is determined by the amount of light passing from the medium having the refractive index n into the air and the total amount of light generated (the amount of light totally reflected at the interface between the medium and air and the amount of light From the ratio of (the sum of the amounts of passing light), it can be obtained by the following equation (2).

Η = 1− (n ² −1) ^1/2 / n (2) When the refractive index n of the medium is larger than 1.5, the following approximate expression (3) can be used. When the refractive index n of the medium is very close to 1.00, it is necessary to use the above equation (2).

Η = 1 / (2n ² ) (3) Here, since the thickness of the light emitting layer 3 and the electrode 2 in the flat light emitting plate A is shorter than the wavelength of light, the refractive index of the glass plate 1 is mainly determined by the extraction efficiency η. Will contribute. And since the refractive index n of glass is generally about 1.5 to 1.6,
From the equation (3), the takeout rate η is about 0.2 (about 20%). The remaining 80% is lost as guided light due to total reflection at the interface between the glass plate 1 and air.

[0008]

As described above, the flat light-emitting plate A has a problem that the light emission of the light-emitting layer 3 from the surface of the glass plate 1 to the atmosphere is low and the luminance of the surface is low, resulting in darkness. Had.

The present invention has been made in view of the above points, and an object of the present invention is to provide a flat light emitting plate having a high light extraction rate and a high surface luminance and a method of manufacturing the flat light emitting plate. It is another object of the present invention to provide a bright flat-panel CRT display and a field emission display using such a flat light-emitting plate.

[0010]

According to a first aspect of the present invention, there is provided a flat light emitting plate which is formed by providing an electrode and a light emitting layer which emits light when irradiated with an electron beam on a glass plate. An airgel thin film 4 is provided between the plate 1 and the light emitting layer 3.

According to a second aspect of the present invention, a transparent electrode 2a and a light emitting layer 3 are provided on a glass plate 1 in this order, and an airgel thin film 4 is provided between the glass plate 1 and the transparent electrode 2a. It is characterized by the following.

According to a third aspect of the present invention, a transparent electrode 2a and a light emitting layer 3 are provided on a glass plate 1 in this order, and an airgel thin film 4 is provided between the transparent electrode 2a and the light emitting layer 3. It is characterized by the following.

According to a fourth aspect of the present invention, a light emitting layer 3 and a metal electrode 2b are provided in this order on a glass plate 1, and an airgel thin film 4 is provided between the glass plate 1 and the light emitting layer 3. It is characterized by the following.

A flat light emitting plate according to a fifth aspect of the present invention is formed by providing an electrode 2 and a light emitting layer 3 that emits light when irradiated with an electron beam on a glass plate 1, and the light emitting layer 3 is formed of phosphor particles. Is formed of an airgel thin film 4 in which is dispersed or carried.

According to a sixth aspect of the present invention, there is provided a method for manufacturing a flat light emitting plate according to the second aspect of the present invention, wherein a silica airgel is formed by applying and drying an alkoxysilane solution on a glass plate 1 when manufacturing the flat light emitting plate. After the thin film 4 is formed, a transparent conductive film is formed thereon by a vapor phase method to provide a transparent electrode 2a, and the light emitting layer 3 is further formed thereon.

According to a seventh aspect of the present invention, there is provided a method for manufacturing a flat light emitting plate according to the third aspect, wherein a transparent conductive film is formed on a glass plate 1 to form a transparent electrode 2a. Is formed, and a silica airgel thin film 4 is formed thereon by applying and drying an alkoxysilane solution, and then the light emitting layer 3 is further formed thereon.

According to the method for manufacturing a flat light emitting plate according to claim 8 of the present invention, in manufacturing the flat light emitting plate according to claim 4, silica aerogel is obtained by applying and drying an alkoxysilane solution on the glass plate 1. Forming a thin film 4,
After the light emitting layer 3 is formed thereon, a metal thin film is further formed thereon to provide the metal electrode 2b.

A flat CRT display according to a ninth aspect of the present invention includes the flat light emitting plate A according to any one of the first to fifth aspects and an electron gun 5a for irradiating the light emitting layer 3 with an electron beam. It is characterized by comprising.

According to a tenth aspect of the present invention, there is provided a field emission display according to any one of the first to fifth aspects, and a field emission electron beam source 5b for irradiating the light emitting layer 3 with an electron beam. Characterized by comprising:

[0020]

Embodiments of the present invention will be described below.

The flat light-emitting plate A according to the present invention comprises a glass plate 1
Is formed by providing an electrode 2 and a light-emitting layer 3 on one surface of the substrate, and providing an airgel thin film 4 between the glass plate 1 and the light-emitting layer 3. In the embodiment of FIG. An electrode 2 and a light emitting layer 3 are provided in this order on one surface of 1, and an airgel thin film 4 is provided between the glass plate 1 and the electrode 2. In the embodiment shown in FIG. 1, a transparent electrode 2a is used as the electrode 2.

Here, the glass plate 1 also functions as the glass plate 1 which carries the strength of the flat light emitting plate A.
The thickness is not particularly limited as long as it can maintain strength.

The aerogel thin film 4 is formed of silica aerogel. Since the silica aerogel is transparent and has a refractive index similar to that of air, the outgoing rate of light obtained from the above equation (2) is obtained. η is 1 (100%)
It is possible to improve to near. The formation of the airgel coating 4 on the surface of the glass plate 1 can be performed by applying and drying an alkoxysilane solution on the surface of the glass plate 1. Hereinafter, formation of the silica airgel thin film 4 will be described in detail.

In the present invention, the alkoxysilane solution is
It can be prepared by mixing and mixing an alkoxysilane (also referred to as a silicon alkoxide or an alkyl silicate), a catalyst for causing a hydrolysis polymerization reaction of the alkoxysilane, water, and, if necessary, a solvent.

As the above-mentioned alkoxysilane, various kinds of conventionally known silica airgel raw materials disclosed in Japanese Patent Application Laid-Open No. Hei 5-279011 can be used.
There are trifunctional alkoxysilanes and tetrafunctional alkoxysilanes. Examples of the bifunctional alkoxysilane include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldiethoxysilane, diphenyldimethoxysilane,
Methylphenyldiethoxysilane, methylphenyldimethoxysilane, diethyldiethoxysilane, diethyldimethoxysilane, etc., as trifunctional alkoxysilane, for example, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, Examples of phenyltrimethoxysilane, phenyltriethoxysilane and the like, and examples of tetrafunctional alkoxysilane include tetramethoxysilane and tetraethoxysilane.

As a catalyst for the hydrolysis polymerization reaction of the alkoxysilane, a basic catalyst such as ammonia, ammonium fluoride and sodium hydroxide can be used.

Further, it is preferable to use a solvent which is compatible with water and dissolves alkoxysilane. Examples of such a solvent include methanol, ethanol, and the like.
One selected from isopropanol and acetonitrile can be used alone or in combination of two or more. The alkoxysilane solution may contain a low volatility solvent such as polyethylene glycol, N, N dimethylformamide, dipropylene glycol monomethyl ether, etc. In the process of forming the gel-like compound, there is a possibility that a desired gel-like compound may not be obtained. Therefore, it is preferable to keep the concentration within 20% by mass.

In the alkoxysilane solution of the present invention,
The mixing ratio of the alkoxysilane, the hydrolysis polymerization reaction catalyst of the alkoxysilane, water, and the solvent is such that the hydrolysis polymerization reaction catalyst of the alkoxysilane is 0.01 to 1 part by mass with respect to 100 parts by mass of the alkoxysilane. 50 to 200
It is preferable to set the mass parts and the solvent in the range of 100 to 1000 parts by mass.

First, the surface of the glass plate 1 is thinly coated with this alkoxysilane solution. It is desirable that the glass plate 1 be subjected to a surface treatment for improving the wettability of the alkoxysilane solution and the adhesion of the thin film in advance. For example, it is possible to perform etching such as alkali etching using an aqueous alkali solution containing sodium orthosilicate, plasma etching, UV ozone irradiation etching, or apply and dry a primer coating solution for imparting adhesion.

The method of coating the surface of the glass plate 1 with an alkoxysilane solution includes spin coating,
Any method such as dip coating, bar coating, roll coating, and spray coating can be used. Appropriate methods can be adopted according to the viscosity, gelation time, and time-dependent change in properties until gelation due to the composition of the alkoxysilane solution. Among these methods, spin coating is considered in consideration of versatility. The method is most preferred.

In coating the surface of the glass plate 1 with the alkoxysilane solution, the coating atmosphere is preferably a saturated vapor pressure atmosphere of a solvent contained in the alkoxysilane solution. The coating conditions are appropriately selected according to the viscosity of the alkoxysilane solution, the gelation time, and the surface characteristics of the glass plate 1.
For example, the alkoxysilane solution changes from lipophilic to hydrophilic between immediately after the preparation and the gelation, and the viscosity increases with time, so that the coating start time on the glass plate 1 and the rotation in the case of spin coating are changed. The number, the dipping / pulling-up time in the case of dip coating, the pattern of the bar groove in the case of bar coating, the discharge amount in the case of spray coating, etc. are selected according to the desired film thickness. If the coating start time is too early, the wettability with the glass plate 1 is poor, and it is difficult to form a silica airgel thin film with a uniform film thickness. If the coating start time is too late, the viscosity increases too much. Also in this case, the thickness of the silica airgel thin film may be uneven. The coating start time is, for example, a density of 0.1 g / c.
When forming the silica airgel thin film 4 of m ³ , it is preferable that the mixing time is in the range of 1 to 3 minutes after the preparation of the alkoxysilane solution.

The coating thickness of the alkoxysilane solution is not particularly limited, but is preferably set in the range of 1 μm to 2 mm. When the thickness increases beyond this range, the silica airgel thin film 4 can be formed,
When the glass plate 1 on which the silica airgel thin film 4 is formed is bent or handled, the surface of the silica airgel thin film 4 is easily damaged. If the thickness is smaller than this range, cracks are likely to occur due to evaporation of a small amount of the solvent from the gel compound, even if the coating atmosphere is a saturated vapor pressure atmosphere of the solvent. Since the occurrence of the crack occurs instantaneously, it is difficult to avoid this in an actual process.

When the surface of the glass plate 1 is thinly coated with the alkoxysilane solution as described above, the alkoxysilane in the alkoxysilane solution is hydrolyzed with water by the action of a hydrolysis polymerization reaction catalyst and undergoes a polymerization reaction to gel. Then, a thin film of a gel-like compound in a wet state comprising a silica skeleton is formed. Then, the thin gel-like compound on the surface of the glass plate 1 is cured. If the curing step is omitted, the silica airgel undergoes whitening and shrinkage in the supercritical drying step due to its weak structure. If this curing is not carried out in a non-dry atmosphere, whitening and shrinkage occur similarly, and further cracks may occur. In order to carry out curing in a non-dry atmosphere, generally, the glass plate 1 coated with the alkoxysilane solution is left in a closed container or left under a saturated vapor pressure atmosphere of a solvent contained in the alkoxysilane solution. However, when a thin film is prepared as in the present invention, since the surface area of the gel compound with respect to the volume of a closed container or a saturated vapor pressure atmosphere is large, the solvent contained from the thin film gel compound is contained. In addition, volatilization and diffusion of the catalyst and the contained catalyst tend to proceed, and it is difficult to effectively prevent whitening, shrinkage, and cracks. In order to prevent the contained catalyst from diffusing out of the gel-like compound, it is conceivable to saturate the catalyst gas into the curing atmosphere, but this method is not uniform due to the difference in the curing conditions between the surface and the inside of the gel-like compound. In this case, it is difficult to prevent the occurrence of cracks and changes in physical properties. It is also conceivable to perform curing while immersing the gel compound in a solvent contained in the alkoxysilane solution. In this case, although the damage due to drying is avoided, the gel compound is contained. There is a possibility that the catalyst and water may diffuse out of the solvent, and similarly, it is difficult to prevent the occurrence of cracks and changes in physical properties.

Then, the gel-like compound in the form of a thin film on the surface of the glass plate 1 is cured by using a curing solution prepared by containing water and a catalyst for the hydrolysis and polymerization of alkoxysilane. It is preferable to carry out by immersing in a solution. When a solvent is contained in the alkoxysilane solution, it is preferred that the curing solution also contains a solvent. The water in the curing solution, the hydrolysis polymerization reaction catalyst, the content of the solvent is preferably set to the same volume concentration or molar concentration as the alkoxysilane solution, but it is not necessarily required to be the same, each in the alkoxysilane solution ± of the numerical value of the concentration
If it is within the range of 50%, there is no hindrance to the desired curing.

As the catalyst for the hydrolysis and polymerization reaction of alkoxysilane in the curing solution, it is preferable to use the same catalyst as the hydrolysis and polymerization reaction catalyst contained in the alkoxysilane solution. It is preferable to use the same solvent as that contained in the alkoxysilane solution.

In curing the thin gel-like compound on the surface of the glass plate 1, the film is immersed in a curing solution containing water, an alkoxysilane hydrolysis polymerization catalyst, and a solvent. In addition to preventing the gel-like compound from drying, the hydrolysis-polymerization reaction catalyst in the gel-like compound can be prevented from being diffused or the solvent being volatilized. It is possible to effectively prevent whitening, shrinkage, and cracks from occurring. Here, after the coating is completed, it is preferable to immerse the composition in the curing solution within one hour after the gelation is confirmed. The immersion time in the curing solution depends on the temperature, but is preferably kept within one week.

After a thin film of a gel compound of alkoxysilane is formed on the surface of the glass plate 1 as described above, the gel compound is supercritically dried. It is preferable to impart hydrophobicity to the silica airgel film by subjecting the compound to a hydrophobic treatment. The hydrophobic silica airgel imparted with hydrophobicity as described above can prevent moisture, water, and the like from penetrating, and can prevent the performance of the silica airgel film, such as the refractive index, light transmittance, and heat insulation, from deteriorating. It is. The hydrophobizing treatment is performed in order to make the hydroxyl group of the silanol group present on the surface of the gel compound react with the functional group of the hydrophobizing agent, and to replace the hydrophobic group with the hydrophobic group of the hydrophobizing agent to make the surface hydrophobic. . As a method for performing the hydrophobic treatment, Japanese Patent Application Laid-Open No.
As disclosed in JP-A-79011 and JP-A-7-138375, for example, a gel is immersed in a hydrophobizing solution obtained by dissolving a hydrophobizing agent in a solvent, and mixed, for example, to form a gel. There is a method in which after the hydrophobizing agent is permeated, heating is performed as necessary to cause a hydrophobizing reaction.

Here, as the hydrophobizing agent, an organic silane compound having a functional group capable of reacting with the silanol group of the gel compound and a hydrophobic group is used.
For example, hexamethyldisilazane, hexamethyldisiloxane, trimethylmethoxysilane, dimethyldimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, trimethylethoxysilane, dimethyldiethoxysilane, methyltriethoxysilane, and the like can be given.

Examples of the solvent used for the hydrophobizing treatment include methanol, ethanol, isopropanol, xylene, toluene, benzene, N, N-dimethylformamide, hexamethyldisiloxane and the like. Is not limited to these as long as it can be easily dissolved and can be replaced by the solvent contained in the gel compound before the hydrophobic treatment. In the case where supercritical drying is performed in a subsequent step, a medium which can be easily subjected to supercritical drying, for example, the same type as that of methanol, ethanol, isopropanol, liquid carbon dioxide, or the like, or a medium which can be replaced with the same is preferable.

After hydrophobizing the gel-like compound in the form of a thin film as described above, it is dried in a supercritical state above the critical point of the solvent in the presence of a solvent (dispersion medium) such as alcohol or carbon dioxide. A thin film of silica airgel can be obtained while being laminated on the surface of the glass plate 1. In supercritical drying, for example, the gel-like compound on the surface of the glass plate 1 is immersed in liquefied carbon dioxide (about 50 to 60 atm (about 5.1 to 6.1 MPa)), and all or one of the solvents contained in the gel-like compound is removed. Part by substituting liquefied carbon dioxide having a lower critical point than this solvent, and then drying under supercritical conditions of a single system of carbon dioxide or a mixed system of carbon dioxide and a solvent. .

The refractive index of the silica airgel thin film 4 obtained as described above can be freely changed depending on the mixing ratio of the raw materials of the silica airgel, but in order to secure the performance such as the transparency of the silica airgel, 1.008
It is preferable to adjust the refractive index in the range of １．１1.18. The thickness of the silica airgel thin film 4 is preferably set in the range of 1 μm to 2 mm.

The transparent electrode 2a provided on the surface of the airgel thin film 4 is made of indium tin oxide (ITO, In ₂ O ₃ --S
nO ₂ ), indium zinc oxide (In ₂ O ₃ —ZnO),
It can be formed using a transparent conductive film made of an inorganic oxide such as zinc aluminum oxide or a metal such as silver or chromium. The thickness of the transparent electrode 2a is not particularly limited, but is about 100 to 500 nm in the case of an inorganic oxide and 2 to 10 in the case of a metal in order to maintain transparency and conductivity.
About nm is preferable. The method of forming the transparent conductive film on the surface of the airgel thin film 4 is not particularly limited, but is preferably performed by a gas phase method (vapor phase deposition method) such as sputtering, so that the airgel thin film 4 is hardly damaged. It is preferred in that respect.

The light emitting layer 3 provided on the surface of the transparent electrode 2a is formed of a phosphor that emits light by being excited by an electron beam when irradiated with an electron beam. As the phosphor, ZnS · SmF, ZnS · Mn, ZnSTbF ₃ ,
Although it is preferable to use an inorganic phosphor such as CaS.Eu, it can be appropriately selected and used according to a required color.

The method for forming the light emitting layer 3 with a phosphor on the surface of the transparent electrode 2a is not particularly limited, but a printing method, a sputtering method, or the like can be used. In the printing method, a phosphor is mixed with a polymer or water as needed to prepare a slurry, and the phosphor slurry is screen-printed on the surface of the transparent electrode 2a, dried, and further dried.
The light emitting layer 3 is formed of a phosphor by firing at about ° C. For example, the phosphor ZnS
25 g of Mn (“NP-1015” manufactured by NICHIA)
A slurry is prepared by mixing 12 g of terpineol, 1 g of dibutyl phosphate, and 1 g of ethyl cellulose, and the phosphor layer can be used to form the light emitting layer 3 using the phosphor slurry. The sputtering method has an output of 200 W and a temperature of 200.
C. and a degree of vacuum of about 0.7 Pa.

The thickness of the light emitting layer 3 is not particularly limited, but when the light emitting layer 3 is formed of a phosphor by a printing method, the thickness is preferably set to about 0.1 μm to 500 μm. Also, the light emitting layer 3 made of a phosphor by a sputtering method.
Is formed, the thickness is preferably about 0.05 μm to 1 μm, and the thinner the better, the better.

The flat light-emitting plate A formed as described above is
The electron beam source 5 is disposed so as to face the side of the glass plate 1 on which the light emitting layer 3 is laminated, and is used between the transparent electrode 2a and the electron beam source 5 so that the transparent electrode 2a becomes an anode electrode. Is connected to a power source 6 to apply a voltage.
When the electron beam is emitted from the electron beam source 5, the electron beam is drawn by the transparent electrode 2a of the anode electrode, and the light emitting layer 3 is irradiated with the electron beam, so that the light emitting layer 3 emits and emits an electron beam.
The light emitted from the light emitting layer 3 enters the glass plate 1 through the transparent electrode 2a and the airgel thin film 4, and is emitted from the surface of the glass plate 1 to exhibit a function as a display.

Here, since the airgel thin film 4 having a refractive index close to 1 is provided between the light emitting layer 3 and the glass plate 1, the light emitted from the light emitting layer 3 enters the glass plate 1 at a small incident angle. Then, the light is emitted from the surface of the glass plate 1 and the rate of loss as guided light is reduced, and the extraction rate η from the surface of the glass sheet 1 is increased. Therefore, the flat light emitting plate A has a high surface brightness. Since the airgel thin film 4 has a refractive index close to 1, once emitted light is emitted into the airgel thin film 4 having a refractive index close to 1 and a thickness of 1.0 μm or more, the light is refracted. It is taught by the law of refraction of classical optics that the entire amount of light can be extracted into the air even though it passes through a glass plate 1 whose modulus is much greater than 1.

When a flat CRT display is formed using the flat light-emitting plate A, an electron gun 5a is used as the electron beam source 5, and an electron beam is emitted from the electron gun 5a to the light-emitting layer of the flat light-emitting plate A. By irradiating 3,
A plurality of flat light-emitting plates A arranged in front of a flat-panel CRT display can emit light to perform display.

When a field emission display (FED) is formed using the flat light emitting plate A,
A field emission electron beam source 5b is used as the electron beam source 5. The field emission electron beam source 5b is a Spindt type,
Any type such as a surface conduction element and a ballistic electron type can be used and is not particularly limited. Then, the field emission electron beam source 5b irradiates the light emitting layer 3 of the flat light emitting plate A with an electron beam, thereby causing a large number of the flat light emitting plates A arranged in front of the field emission display to emit light, thereby performing display display. That can be done.

In the embodiment shown in FIG. 2, a transparent electrode 2a and a light emitting layer 3 are provided in this order on one surface of a glass plate 1, and an airgel thin film 4 is provided between the transparent electrode 2a and the light emitting layer 3 to form a flat surface. The light emitting plate A is formed. The formation of the transparent electrode 2a on the surface of the glass plate 1, the formation of the airgel thin film 4 on the surface of the transparent electrode 2a, and the formation of the light emitting layer 3 on the surface of the airgel thin film 4 are performed in the same manner as described above. The light emitting plate A can be manufactured.

Also in this flat light emitting plate A, similarly to the above, the electron beam source 5 is used so as to be opposed to the side on which the light emitting layer 3 of the glass plate 1 is laminated. A power source 6 is connected between the transparent electrode 2a and the electron beam source 5 so that the electrode 2a becomes an anode electrode, a voltage is applied, and the electron beam source 5 emits an electron beam. The light-emitting layer 3 is irradiated with an electron beam by being drawn by the electrode 2a, and the light-emitting layer 3 emits and emits an electron beam. The light emitted from the light-emitting layer 3 enters the glass plate 1 through the airgel thin film 4 and the transparent electrode 2a, and is emitted from the surface of the glass plate 1 to exhibit a function as a display. Even in this case, since the airgel thin film 4 having a refractive index close to 1 is provided between the light-emitting layer 3 and the glass plate 1, light emitted from the light-emitting layer 3 enters the glass plate 1 at a small incident angle. The incident light is emitted from the surface of the glass plate 1, the rate of loss as guided light is reduced, and the extraction rate from the surface of the glass plate 1 is increased. The brightness is increased. Although the transparent electrode 2a is interposed between the glass plate 1 and the airgel thin film 4, the thickness of the transparent electrode 2a is smaller than the wavelength of light, and thus does not affect the light extraction rate.

Also, by using the electron gun 5a as the electron beam source 5, a flat-panel CRT display can be formed using the flat light-emitting plate A. As the electron beam source 5, a field emission electron beam source 5b Is used, a field emission display (FED) can be formed using the flat light emitting plate A.

FIG. 3 shows another embodiment of the present invention, in which a metal electrode 2b is used as an electrode 2. A light emitting layer 3 and a metal electrode 2b are provided on one surface of a glass plate 1. In this order, the airgel thin film 4 is provided between the glass plate 1 and the light emitting layer 3 to form the flat light emitting plate A. Airgel thin film 4 on the surface of glass plate 1
And the formation of the light emitting layer 3 on the surface of the airgel thin film 4 can be performed in the same manner as described above.

As the metal electrode 2b, Al, Pt,
Any metal having good conductivity such as Au, Ag, and Mg can be used without particular limitation. Since the metal electrode 2b does not need to be formed transparent, it can be formed thicker than in the case of the transparent electrode 2a described above, and the thickness is preferably about 50 to 200 nm. The metal electrode 2b can be formed by an arbitrary method such as a vapor phase method (vapor phase deposition method) such as vacuum deposition or sputtering.

Also in this flat light emitting plate A, similarly to the above, the electron beam source 5 is disposed so as to be opposed to the side on which the light emitting layer 3 of the glass plate 1 is laminated. A power source 6 is connected between the metal electrode 2b and the electron beam source 5 so that a voltage is applied so that the electrode 2b becomes an anode electrode. Here, the metal electrode 2b can be formed to have a large thickness, and the conduction performance can be enhanced. Therefore, a high voltage can be applied between the metal electrode 2b and the electron beam source 5. Therefore, when the electron beam is emitted from the electron beam source 5, the electron beam is strongly attracted to the metal electrode 2b of the anode electrode, penetrates through the metal electrode 2b, and is irradiated with the electron beam to the light emitting layer 3. 3 emits light by excitation with an electron beam. The light emitted from the light emitting layer 3 enters the glass plate 1 through the airgel thin film 4 and is emitted from the surface of the glass plate 1 to exhibit a function as a display. Even in this case, the light emitting layer 3 and the glass plate 1
The light emitted from the light emitting layer 3 is incident on the glass plate 1 at a small angle of incidence and is emitted from the surface of the glass plate 1 because the airgel thin film 4 having a refractive index close to 1 is provided between them. Yes, the rate of loss as guided light is reduced,
The take-out rate from the surface of the glass plate 1 increases, and the flat light-emitting plate A increases the surface brightness.
In addition, of the light emitted from the light emitting layer 3, the light emitted to the side opposite to the glass plate 1 is reflected by the metal electrode 2 b as a mirror, and this light can also be emitted through the glass plate 1, and the planar light emission This makes it possible to further increase the luminance of the surface of the plate A.

By using the electron gun 5a as the electron beam source 5, a flat-panel CRT display can be formed using the flat light-emitting plate A. As the electron beam source 5, a field emission electron beam source 5b Is used, a field emission display (FED) can be formed using the flat light emitting plate A.

In each of the above embodiments, the light emitting layer 3 and the airgel thin film 4 are formed as separate independent layers. However, in the embodiment of FIG. 4, the light emitting layer 3 is formed by dispersing or supporting phosphor particles. The light emitting layer 3 and the airgel thin film 4 are formed in one layer. When such a light emitting layer 3 is formed of an airgel thin film 4 in which phosphor particles are dispersed or supported, phosphor particles are mixed with the above-described alkoxysilane solution, and an alkoxysilane solution obtained by mixing the phosphor particles is used. Can be carried out by applying and drying as described above.
Here, the mixing ratio of the phosphor particles to the alkoxysilane solution is preferably set to about 10 to 60% by volume with respect to the alkoxysilane solution, and the particle diameter of the phosphor particles is not particularly limited; 0.1 to 100 μm, and the finer the more, the better.

In the embodiment shown in FIG. 4A, an airgel thin film 4 in which phosphor particles are dispersed or supported is formed on one surface of a glass plate 1, and a metal electrode 2b is formed on the surface of the airgel thin film 4. Thus, a flat light emitting plate A is manufactured. Even in the flat light emitting plate A, the electron beam source 5 is used so as to be opposed to the side of the glass plate 1 on which the airgel thin film 4 also serving as the light emitting layer 3 is laminated,
Metal electrode 2b so that metal electrode 2b becomes an anode electrode
A power supply 6 is connected between the power supply 6 and the electron beam source 5 to apply a high voltage. When the electron beam is emitted from the electron beam source 5, the electron beam is strongly attracted to the metal electrode 2b of the anode electrode, penetrates through the metal electrode 2b, and irradiates the phosphor particles in the airgel thin film 4 with the electron beam. Thus, the phosphor particles emit light by excitation with an electron beam. The light emitted from the phosphor particles in the airgel thin film 4 enters the glass plate 1 through the airgel thin film 4 and is emitted from the surface of the glass plate 1 to exhibit a function as a display. In this device, light is incident on the glass plate 1 from the aerogel thin film 4 having a refractive index close to 1, so that the light is incident on the glass plate 1 at a small incident angle without being totally reflected. The light is emitted from the surface, the rate of being lost as guided light is reduced, and the extraction rate from the surface of the glass plate 1 is increased. The flat light-emitting plate A has a higher surface brightness.

In the embodiment shown in FIG. 4B, a transparent electrode 2a is formed on one surface of a glass plate 1, and an airgel thin film 4 in which phosphor particles are dispersed or supported is formed on the surface of the transparent electrode 2a. Thus, a flat light emitting plate A is manufactured. This flat light-emitting plate A is also used in which the electron beam source 5 is arranged so as to face the side of the glass plate 1 on which the airgel thin film 4 serving also as the light-emitting layer 3 is laminated, and the transparent electrode 2a is provided. A power source 6 is connected between the transparent electrode 2a and the electron beam source 5 so as to serve as an anode electrode, and a voltage is applied. When an electron beam is emitted from the electron beam source 5, the electron beam is attracted to the transparent electrode 2a of the anode electrode, and the phosphor particles in the airgel thin film 4 are irradiated with the electron beam, and the phosphor particles emit and emit an electron beam. . The light emitted from the phosphor particles in the airgel thin film 4 is
Then, the light enters the glass plate 1 through the transparent electrode 2a and exits from the surface of the glass plate 1 to exhibit a function as a display. In this device, light enters the glass plate 1 through the aerogel thin film 4 having a refractive index close to 1, so that the light enters the glass plate 1 at a small incident angle and exits from the surface of the glass plate 1. That is, the rate of loss as guided light is reduced, and the takeout rate from the surface of the glass plate 1 is increased. The flat light-emitting plate A has a higher surface brightness.

4A and 4B, a flat CRT display can be formed using the flat light emitting plate A by using the electron gun 5a as the electron beam source 5. By using the field emission electron beam source 5 b as the electron beam source 5, a field emission display (FED) can be formed using the flat light emitting plate A.

[0061]

Next, the present invention will be described specifically with reference to examples.

Example 1 A solution was prepared by mixing an oligomer of tetramethoxysilane (“Methylsilicate 51” manufactured by Colcoat Co., Ltd.) and methanol at a mass ratio of 47:81. Liquid B was prepared by mixing methanol at a mass ratio of 50: 1: 81. Then, an alkoxysilane solution obtained by mixing the solution A and the solution B at a mass ratio of 16:17 was mixed for 1 minute and 30 seconds after the start of mixing, and 50 seconds after the end of the mixing, soda glass whose surface was alkali-cleaned beforehand. The glass plate 1 was placed in a rotating chamber of a spin coater, and the glass plate 1 was rotated to spin-coat the surface of the glass plate 1 with an alkoxysilane solution. Here, the rotation chamber of the spin coater was previously charged with methanol so as to be in a methanol atmosphere, and the glass plate 1 was rotated at 700 rpm for 10 seconds. After spin-coating the alkoxysilane solution in this manner, the alkoxysilane is allowed to gel by leaving it for 3 minutes, and then the glass plate on which the thin gel-like compound has been formed is treated with water: 28% by mass ammonia water: methanol = 162. : 4: 640 immersed in a curing solution having a composition of mass ratio, and cured at room temperature for 24 hours. Next, the gel-like compound in the form of a thin film formed on the surface of the glass plate 1 is washed by immersing it in isopropanol, then put in a high-pressure vessel, filling the high-pressure vessel with liquefied carbon dioxide gas, at 80 ° C. and 16 MPa.
a) Supercritical drying was performed under the conditions of 2 hours to form a 20 μm-thick silica airgel thin film 4 on the surface of the glass plate 1.

Next, the surface of the airgel thin film 4 provided on the glass plate 1 as described above was applied at 200 ° C., 1 Pa, 100 W
By sputtering under the conditions of
A transparent electrode 2a is formed by forming an ITO film having a thickness of 200 nm, a pressure of 0.7 Pa and a pressure of 200 Pa on the surface of the transparent electrode 2a.
By sputtering under the condition of W, a thickness of 10
A planar light emitting plate A as shown in FIG. 1 was produced by forming a light emitting layer 3 by forming a film of ZnS.Mn of 0 nm.

(Example 2) A glass plate 1 manufactured by Sanyo Vacuum Co., Ltd. having a transparent electrode 2a made of an ITO film on the surface was used, and an airgel thin film 4 was coated on the surface of the transparent electrode 2a in the same manner as in Example 1. After the formation, 2
Sputtering is performed under the conditions of 00 ° C., 0.7 Pa, and 200 W to form a 100 nm-thick ZnS · Mn film, and the light emitting layer 3 is provided.
Was prepared.

Example 3 After forming the airgel thin film 4 on the surface of the glass plate 1 in the same manner as in Example 1, sputtering was performed on the surface of the airgel thin film 4 at 200 ° C., 0.7 Pa, and 200 W. By the thickness 100n
By forming a light emitting layer 3 by forming a ZnS.Mn film having a thickness of 100 nm and forming a metal electrode 2b on the surface of the light emitting layer 3 by forming an Al film having a thickness of 100 nm by a vacuum evaporation method, as shown in FIG. A flat light emitting plate A was produced.

Example 4 A solution was prepared by mixing an oligomer of tetramethoxysilane (“Methylsilicate 51” manufactured by Colcoat) in a mass ratio of 47:81, and prepared water, 28% by mass aqueous ammonia, Liquid B was prepared by mixing methanol at a mass ratio of 50: 1: 81. And, as phosphor particles, ZnS · Mn (“NP” manufactured by NICHIA)
-1015 "), the phosphor particles, solution A and solution B
By mixing at a volume ratio of 0:29:31, an alkoxysilane solution in which the phosphor particles were dispersed was prepared, and 1 minute and 30 seconds after the start of mixing and 50 seconds after the end of mixing,
The solution was dropped on a glass plate 1 manufactured by Sanyo Vacuum Co., having a transparent electrode 2a made of an ITO film on the surface, and spin-coated in the same manner as in Example 1. Further, gelation, curing, and supercritical drying were performed in the same manner as in Example 1 to form a 20 μm-thick silica airgel thin film 4 containing phosphor particles, thereby obtaining a flat light-emitting plate as shown in FIG. A was prepared.

(Comparative Example 1) A glass plate 1 manufactured by Sanyo Vacuum Co., having a transparent electrode 2a made of an ITO film on the surface, was used.
A flat light emitting plate having no silica airgel thin film 4 was prepared by forming a light emitting layer 3 by forming Mn.

(Comparative Example 2) ZnS.Mn was formed on the surface of the soda glass plate 1 in the same manner as in Example 1 to provide the light emitting layer 3, and further on the surface of the light emitting layer 3 in the same manner as in Example 2. Forming the metal electrode 2b by depositing Al
A flat light emitting plate having no silica airgel thin film 4 was produced.

In the vacuum chamber of 133 × 10 ⁻⁷ Pa (10 ⁻⁷ torr), the flat light-emitting plates of Examples 1 to 4 and Comparative Examples 1 and 2 were placed at a distance of 1 cm from the Spindt-type electron beam source. And applying a drive voltage of 1 kV between the electrode of the flat light emitting plate and the Spindt-type electron beam source while applying a voltage of 5 kV.
An electron beam was emitted from the Spindt-type electron beam source at 00 V, and the flat light emitting plate was allowed to emit light. Then, the brightness of the surface of the glass plate of the flat light emitting plate was measured from an angle of 45 ° with respect to the normal line. Table 1 shows the results.

[0070]

[Table 1]

As can be seen from Table 1, it is confirmed that each of the examples has a high surface luminance and a high light extraction rate.

[0072]

As described above, the flat light-emitting plate according to the first aspect of the present invention is formed by providing a light-emitting layer that emits light when irradiated with an electrode and an electron beam on a glass plate. Since the airgel thin film is provided between the layers, the light emitted from the light-emitting layer enters the glass plate through the airgel thin film having a small refractive index and exits from the surface of the glass plate, and is lost as guided light. Becomes smaller, the takeout rate from the surface of the glass plate increases, and the luminance of the surface of the flat light emitting plate increases.

According to the second aspect of the present invention, a transparent electrode and a light emitting layer are provided on a glass plate in this order, and an airgel thin film having a small refractive index is provided between the glass plate and the transparent electrode. The light emitted from the layer enters the glass plate through the transparent electrode and the airgel thin film having a small refractive index, and is emitted from the surface of the glass plate.The rate of loss as guided light is reduced, and the light emitted from the surface of the glass plate is reduced. This increases the takeout rate and increases the luminance of the surface of the flat light emitting plate.

According to the third aspect of the present invention, light is emitted from the light emitting layer because the transparent electrode and the light emitting layer are provided on the glass plate in this order, and the airgel thin film is provided between the transparent electrode and the light emitting layer. Light is incident on the glass plate through the airgel thin film and transparent electrode with a small refractive index, and is emitted from the surface of the glass plate.The rate of loss as guided light is small, and the extraction rate from the surface of the glass plate is high. Become
The brightness of the surface of the flat light emitting plate is increased.

According to the fourth aspect of the present invention, the light emitting layer and the metal electrode are provided on the glass plate in this order, and the airgel thin film is provided between the glass plate and the light emitting layer. Light is incident on the glass plate through the airgel thin film having a small refractive index, and is emitted from the surface of the glass plate.The rate of loss as guided light is reduced, and the extraction rate from the surface of the glass plate is increased. The light of the light emitting layer can be reflected by the metal electrode and emitted from the surface of the glass plate, and the brightness of the surface of the flat light emitting plate is increased.

The flat light-emitting plate according to claim 5 of the present invention is formed by providing a light-emitting layer which emits light by irradiating an electrode and an electron beam on a glass plate, and the light-emitting layer disperses or emits phosphor particles. Since the airgel thin film is formed of a supported airgel thin film, when the airgel thin film is irradiated with an electron beam, the phosphor particles in the airgel thin film emit light, and the emitted light enters the glass plate from the airgel thin film having a small refractive index. The light emitted from the surface of the glass plate, the rate of loss as guided light decreases, the rate of extraction from the surface of the glass plate increases, and the luminance of the surface of the flat light emitting plate increases. It is.

In the method for manufacturing a flat light emitting plate according to claim 6 of the present invention, in manufacturing the flat light emitting plate according to claim 2, a silica airgel thin film is formed on a glass plate by applying and drying an alkoxysilane solution. After that, a transparent conductive film is formed thereon by a vapor phase method to provide a transparent electrode,
Further, since the light emitting layer is formed thereon, the airgel thin film can be easily formed of silica airgel having a refractive index close to 1 and low.

According to a method of manufacturing a flat light emitting plate according to claim 7 of the present invention, in manufacturing the flat light emitting plate according to claim 3, a transparent conductive film is formed on a glass plate and a transparent electrode is provided. After forming a silica airgel thin film by applying and drying an alkoxysilane solution thereon, a light emitting layer is further formed thereon, so that the airgel thin film is easily formed of silica airgel having a refractive index close to 1 and low. Is what you can do.

In the method for manufacturing a flat light emitting plate according to claim 8 of the present invention, in manufacturing the flat light emitting plate according to claim 4, a silica airgel thin film is formed by applying and drying an alkoxysilane solution on a glass plate. After forming a light emitting layer thereon, a metal thin film is further formed thereon to provide a metal electrode, so that an airgel thin film can be easily formed of silica airgel having a refractive index close to 1 and low. Can be done.

A flat-panel CRT display according to a ninth aspect of the present invention includes the flat light-emitting plate according to any one of the first to fifth aspects and an electron gun for irradiating the light-emitting layer with an electron beam. A bright flat CRT display can be realized by a flat light emitting plate having a high surface luminance.

According to a tenth aspect of the present invention, there is provided a field emission display comprising the flat light emitting plate according to any one of the first to fifth aspects and a field emission electron beam source for irradiating the light emitting layer with an electron beam. The light emitting element is formed so as to have a bright field emission display by a flat light emitting plate having a high surface luminance.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an example of an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of another example of the embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a schematic configuration of another example of the embodiment of the present invention.

FIG. 4 shows a schematic configuration of another example of the embodiment of the present invention, and (a) and (b) are cross-sectional views, respectively.

FIG. 5 is a sectional view showing a schematic configuration of a conventional example.

[Explanation of symbols]

 Reference Signs List 1 glass plate 2 electrode 2a transparent electrode 2b metal electrode 3 light emitting layer 4 airgel thin film 5 electron beam source 5a electron gun 5b field emission electron beam source

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kenji Kono 1048 Kazuma Kadoma, Kadoma-shi, Osaka F-term in Matsushita Electric Works Co., Ltd. DB10 EA05 EB02 ED01 FA02 FB01 FB15 GB10

Claims (10)

[Claims] 1. A flat surface, comprising a glass plate provided with a light emitting layer which emits light when irradiated with an electrode and an electron beam, and an airgel thin film provided between the glass plate and the light emitting layer. Light emitting plate. 2. The planar light emitting device according to claim 1, wherein a transparent electrode and a light emitting layer are provided in this order on a glass plate, and an airgel thin film is provided between the glass plate and the transparent electrode. Board. 3. The planar light emitting device according to claim 1, wherein a transparent electrode and a light emitting layer are provided in this order on a glass plate, and an airgel thin film is provided between the transparent electrode and the light emitting layer. Board. 4. The planar light emitting device according to claim 1, wherein a light emitting layer and a metal electrode are provided in this order on a glass plate, and an airgel thin film is provided between the glass plate and the light emitting layer. Board. 5. A light-emitting layer, which emits light when irradiated with an electrode and an electron beam, is formed on a glass plate, and the light-emitting layer is formed of an airgel thin film in which phosphor particles are dispersed or supported. Features a flat light-emitting plate. 6. A method for manufacturing the flat light emitting plate according to claim 2, wherein a silica airgel thin film is formed on a glass plate by applying and drying an alkoxysilane solution.
A method for manufacturing a flat light-emitting plate, comprising forming a transparent electrode thereon by forming a transparent conductive film by a vapor phase method, and further forming a light-emitting layer thereon. 7. In manufacturing the flat light emitting plate according to claim 3, a transparent conductive film is formed on a glass plate, a transparent electrode is provided, and a silica airgel thin film is formed thereon by applying and drying an alkoxysilane solution. A method for manufacturing a flat light-emitting plate, further comprising forming a light-emitting layer thereon after the formation. 8. In producing the flat light-emitting plate according to claim 4, a silica airgel thin film is formed on a glass plate by applying and drying an alkoxysilane solution, and a light-emitting layer is formed thereon. A method for manufacturing a flat light-emitting plate, comprising forming a metal thin film thereon and providing a metal electrode. 9. A flat-panel CRT display comprising the flat light-emitting plate according to claim 1, and an electron gun for irradiating the light-emitting layer with an electron beam. 10. A field emission display comprising: the flat light-emitting plate according to claim 1; and a field emission electron beam source for irradiating the light-emitting layer with an electron beam.