JPS59138291A - Production of fluorescent film having high light transmittance - Google Patents

Abstract

PURPOSE:To enable the calcination of a fluorescent material easily at a relatively low temperature in a short time, and to obtain a fluorescent film having high light transmittance at a low cost, by gelatinizing the sol of the component constituting the fluorescent material, forming the gel to a film, and calcining the film. CONSTITUTION:Metal alkoxides, organic acid metal compounds or metal salts each containing respective element constituting the matrix of a fluorescent material and respective element constituting the dopant of the fluorescent material are hydrolyzed to obtain a sol containing all elements essential to the fluorescent material. The sol is gelatinized in a vessel having a desired shape to form a film, and calcined at 300-1,300 deg.C to obtain the objective fluorescent film having high light transmittance.

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing transparent phosphors.

More specifically, the present invention relates to a method for producing a transparent phosphor by gelling a sol of phosphor constituents.

In most cases, the fluorescent material is used in the form of an O-type fluorescent film, which is made up of fine particles with a size of several microns to several tens of microns. Since the fluorescent film is made up of fine particles of this size, the following problems may occur. Even when fluorescent light is emitted from a certain phosphor particle, the light hits other phosphor particles several times before exiting the phosphor surface, causing irregular reflections on its surface. After receiving the light, it exits the fluorescent surface. In the case of the fluorescent surface of a cathode ray tube, the influence of this irregular reflection is strong because the fluorescent light emitted from the inner surface is viewed from the outside. As a result, "1 fog" occurs in the image, which deteriorates the contrast and causes a decrease in brightness.

Therefore, if it is possible to create a fluorescent film or a similar fluorescent film that is not composed of fine particles and has no voids between particles, the brightness will be improved, and the contrast and sharpness will also be significantly improved.

In the present invention, the highly transparent fluorescent film is a fluorescent film with extremely few voids in the above-mentioned fluorescent film, and is transparent or has extremely low diffused reflection. ).

Conventionally, there have been the following methods for achieving the same purpose as the present invention.

One method is vacuum deposition. In this method, ordinary phosphor powder is placed in a vapor source and vapor-deposited onto a plate under a vacuum of 5 x 10' mmHg or higher. With a lever, if the vapor deposition is stopped midway through, the raw material phosphor and the resulting phosphor film will have different compositions, so it is necessary to allow the entire vapor deposition to take place. In addition, even if the components in the raw material that are easy to fly fly away first and the raw material chamber is vapor-deposited, a phosphor surface with a different composition is likely to be formed depending on the phosphor.

The highly translucent fluorescent film thus produced exhibits almost no fluorescence as it is. This is said to be due to the fact that the activator does not completely enter the matrix of the phosphor, and that most of the matrix is in an amorphous state and not in a crystalline state. Therefore, by appropriately heating the deposited film, the matrix crystallizes and the activator diffuses into the matrix.The phosphor for which this method is most suitable is a self-activating phosphor. The heat treatment must be carried out under very strict conditions for time and temperature, which is difficult to carry out in practice. Therefore, the method that was considered was to prepare the plate to be deposited in advance. Vapor deposition is performed after heating. According to this method, the deposition time can be shortened and the processing temperature can be completely lowered.

Another method for producing a highly transparent fluorescent film is a gas phase reaction method (chemical vapor deposition). In this method, a phosphor produced by a gas phase reaction is attached to a substrate. This method can be applied to zinc sulfide based phosphors. Specifically, hydrogen sulfide was added to the inside of the container connected to the vacuum system.
Inject at a pressure of 2 + nm Hg. The substrate held inside the container is heated to 500 to 600°C in advance. A small amount of a mixture of metallic zinc and manganese chloride is dropped into this container. This reacts with hydrogen sulfide, and the resulting ZnS:Mn adheres to the substrate. However, the phosphors that can be manufactured using this method are limited.

The present invention is fundamentally different from the above-mentioned vapor deposition method and gas phase reaction method, and uses a sol-gel method to create a highly transparent fluorescent film. It is to be manufactured. This method provides a highly transparent fluorescent film that is much cheaper than conventional methods, and its industrial advantages are immeasurable.

The sol-gel method referred to in the same invention refers to forming a sol by hydrolyzing an organic acid metal compound or metal salt such as a metal alkoxide or metal acetate of the target fluorescent compound as a starting material, and converting this sol into a gel. This is the way to do it.

The sol-gel method will be explained below using 91J as a starting material of a metal alkoxide and a phosphor of a multichamber metal salt phosphor (hereinafter referred to as a lanthanide aluminum/acid phosphor) consisting of a lanthanoid metal and aluminum. The present invention will be explained with reference to the following: 1. U7 Thanoid aluminum/acid phosphors have conventionally been prepared using a lanthanide metal oxide and aluminum oxide as a base material, and a lanthanide metal oxide as an activator. Thoroughly mix and add flux etc. as necessary11500
It was obtained by firing for a long time of more than 10 hours at high temperatures ranging from 7'J to 2000°C or even higher.

However, according to such a conventional method, the obtained lanthanide-based aluminum/acid phosphor is a powder or a phosphor with an irregular shape.

Therefore, in order to obtain the desired highly transparent fluorescent film, a method such as vapor deposition must be used. In addition, in the conventional method, even if the firing temperature is high <L75=, it is necessary to carry out one firing for a long time, and it cannot be easily manufactured, which has been a big problem in industry. Furthermore, in the conventional method, when the powder is obtained, the particle size distribution of the powder is non-uniform. In order to obtain particles with a constant particle size, it is necessary to carry out further classification, etc., resulting in a significantly low yield. Furthermore, the desired particle size cannot always be obtained.

In order to solve the problems of the prior art as described above, the present inventors
As a result of various studies to obtain a lanthanoid aluminate phosphor film with desired shape and particle size, which exhibits high translucency at lower temperatures, we have succeeded in producing the desired lanthanoid aluminate phosphor. When gelling a sol obtained by hydrolyzing the alkoxide of the constituent metal components, the subsequent firing can be easily carried out at a low temperature and in a short time, and it also exhibits high translucency and produces the desired result. It has been found that a lanthanide-based aluminate phosphor with high transparency and shape and particle size can be obtained.

That is, the method for producing a lanthanoid aluminate phosphor of the present invention includes (1) a lanthanide sol obtained by hydrolyzing a lanthanide metal alkoxide (
Mixture of aluminum sol obtained by hydrolyzing aluminum alkoxide with 28m of matrix and activator (11) Mixture of lanthanoid metal alkoxide (two types, matrix and activator) and aluminum alkoxide A sol obtained by hydrolyzing a mixture Th', and (ili) an alkoxide of a composite of a lanthanoid metal and aluminum? After gelling at least one sol of the composite lanthanide aluminum sol obtained by hydrolysis, the sol was heated at 500°C to 100°C.
It is characterized by being fired at a temperature of 300°C.

The lanthanoids referred to in the present invention include 15 rare earth elements La, Ce, and Pr, ranging from lanthanum with an atomic number of 57 to lutetium with an atomic number of 71.

Nd, Pm, Sm, Eu, Gd, Tb, D
Y, Ho.

Er, Tm, Yb, Lu and Yi with atomic number 39
It is a general term.

The above sol mixture (1) can be obtained, for example, as follows.

After reacting the anhydrous halogenated lanthanoid and the alkali metal alkoxide in alcohol, the solvent is replaced with benzene, and the alkali metal halide formed is precipitated and removed by filtration to obtain a benzene solution of the lanthanide alkoxide. Next, water is added to this solution and hydrolyzed to obtain a lanthanide sol, which is a sol of silanthanoid hydroxide. On the other hand, for example, 100 mol of water is added to 1 mol of aluminum alkoxide, hydrolyzed at 75°C, and then 0 mol of water is added to 1 mol of aluminum alkoxide.
．． An aluminum sol is obtained by adding 1 mol of hydrochloric acid and peptizing at 95°C.

A sol mixture (1) is obtained by mixing the lanthanoid sol and the aluminum sol.

The above-mentioned sol (11) can be obtained, for example, as follows.

The lanthanoid alkoxide and aluminum alkoxide are dissolved in benzene with the quantity ratio adjusted to match the composition ratio of the intended lanthanide aluminate phosphor. Next, this solution′! After refluxing for 1 l-4 hours, water is added and hydrolyzed to obtain Schizol (11).

The above composite sol (110) can be obtained, for example, as follows.

An alkali metal is reacted with excess alcohol in a nitrogen stream to synthesize an alkali metal alcoholade, and to this is added an equimolar amount of aluminum alkoxide to the alkali metal.
Reflux for a period of time to synthesize alkali metal aluminum alkoxide. This was added to a lanthanide no-ride alcohol solution, and after refluxing and reacting for 4 hours, the solvent was replaced with be/zene, and the alkali metal)-ride formed was precipitated.
Remove by filtration to obtain a benzene solution of aluminum/thanoid aluminum alkoxide. Next, water is added to this solution and hydrolyzed to obtain a composite 2 tanthanoid aluminum sol tnt+e. In this case, in order to facilitate the formation of a lanthanide aluminate phosphor having the desired composition, a small amount of lanthanide alkoxide or aluminum alkoxide may be added to the nilanthanide aluminum alkoxytonium before hydrolysis.

Among these, the halogen used in the above sol preparation may be any of fluorine, chlorine, bromine and iodine, but chlorine is particularly suitable from the viewpoint of reaction stability. In addition, the alcohol used is methyl alcohol,
Monohydric alcohols such as ethyl alcohol, clovir alcohol, isoclovir alcohol, butyl alcohol, isobutyl alcohol, S-butyl alcohol, amyl alcohol, and isoamyl alcohol, but isoclovir alcohol in particular does not cause problems such as coloring. preferable.

The above (1) (II) and/or (in the method of the present invention)
The sol of No. 110 is gelled by a method such as removing all water. In order to form a transparent thin film or thick film by this gelation, the above-mentioned sol is preferably placed in a container with a low surface energy such as polystyrene, polystyrene, or Teflon and dried. A method of coating on a quartz substrate or the like is also good.

゛In order to obtain a spherical powder through gelation, the sol is stirred in a non-aqueous solvent containing a surfactant, and the difference in interfacial tension between the sol and the solvent is used to form a spherical sol. Remove the drained water and gel it. I ask, what is the stirring speed at this time? By adjusting the amount, a spherical gel material having a diameter of several microns to about 1 gourd can be obtained. In the method of the present invention, the gel material formed as described above is fired for a short time at a temperature of 500°C to 1300°C, thereby producing a highly translucent fluorophore composed of the desired lanthanide aluminate phosphor. A membrane is obtained. The luminescence spectrum of the obtained fluorescent film was exactly the same as that obtained by the conventional method.

According to the method of the present invention as described above, a silanthanoid aluminate phosphor can be obtained by firing at a lower temperature and in a shorter time than in the conventional method, and the amount of energy consumed is low. Further, according to the method of the present invention, when trying to obtain a molded product, a desired shape can be obtained immediately, and when trying to obtain a granular product, it is easy to control the particle size, so that the desired particle size can be easily obtained. The big advantage is that you get something like this.

Furthermore, the biggest advantage is that a higher brightness ratio can be measured compared to conventional powder products. This is 10 to 20 times lower than conventional products.
Improved performance can be obtained.

The above explanation was made using a metal alkoxide as the starting material, but in addition to this method, hydrolysis of an organometallic acid, which is a reaction product of an organic acid and a metal...ride, or a method of hydrolysis of a metal halide can also achieve high light transmittance. It can be a fluorescent film.

Examples of the phosphors that can be produced according to the present invention include phosphors for color TVs as indicated by the P number, phosphors for monochrome TVs, phosphors for various electron tubes, phosphors for low-speed electron tubes,
There are phosphors for electroluminescence, photoconductors, phosphors for Lang, infrared application phosphors, phosphors for phosphorescence, phosphors for radiation, etc., but other known phosphors are also possible. It is.

In particular, oxide phosphors are easy to produce.

- The transparency of the phosphor obtained in the present invention was measured as transmittance.

For transmittance measurement, a 30 m square with a thickness of 1 tV'WL was used.
A lanthanide aluminate phosphor having an average particle size of 6 microns was coated on quartz glass to a thickness of 100 microns by a conventional method by precipitation coating. The transparent phosphor of the present invention was obtained by coating the above-mentioned quartz glass with a lanthanoid aluminum/acid sol and drying it naturally to obtain a smooth gel body of 100β. This is 1
The resulting product was fired at 000° C. for 1 hour to obtain an aluminate phosphor.

Place the measurement sample obtained here on the optical table in a water droplet,
Light is irradiated from a tungsten lung light source at a distance of 00 m1m, and after passing through the measurement sample, it is
Light was received with a photomultiplier having a distance of m1 m, and the transmittance was measured for quartz glass having a thickness of l m/m without being coated with a phosphor. As a result, the transmittance of the phosphor film made by the conventional method was in the range of 5-ios, but the transmittance of the highly transmissive phosphor film according to the present invention was in the range of 30-90 ios.

Fields of application of the present invention include: It can be used without any problems in any place where fluorescent films have been conventionally used. Furthermore, application to high-definition tubes can be considered. This is the case with Benetrayon type cathode ray tubes, which currently use particulate fluorescent light.
'f! Coated inside the CRT. The highly transparent fluorescent film of the present invention is applied as follows.

Three layers of each of the three colors B, G, and H are coated, and a highly transparent insulator 1 (for example, a highly transparent μm 03 S402 film obtained by a sol-gel method) is inserted between the three layers. In this way, a penetration type cathode ray tube with higher brightness and better resolution than ever before can be obtained.

This will be explained below using examples.

Example 1 High-purity yttrium oxide and ammonium chloride were mixed and reacted at a temperature of 350°C for 1 hour.The reaction product, anhydrous yttrium chloride, was extracted with total ethanol, and then the solvent, ethyl chloride, was extracted with ethanol. If exchanged with ingropyl alcohol
The alcoholade obtained by adding fr-0''i metal sodium to a mixed solution of isoglobil alcohol and benzene and refluxing at 82°C was mixed with the above anhydrous yttrium chloride solution, further refluxing at 82°C, and then the solvent was replaced with benzene, sodium chloride was removed by p-filtration, and a benzene/zene solution of yttrium isogloboxoxide was obtained.Water was added to this solution and hydrolyzed to obtain a yttrium sol.

A cerium sol was obtained in the same manner.

Second, 100% per mole of aluminum alkoxide
An aluminum sol was obtained by adding mol of water and hydrolyzing at 75°C, and further adding 0.1 mol of hydrochloric acid per mol of this aluminum alkoxide and peptizing at 95°C.

The yttrium sol and aluminum sol obtained above were mixed at a molar ratio of (a) 1:1, (o) 3:5, and (c) l:2, and then the cerium sol was mixed with C and q.
2.5 x 10' moles of the mixture were mixed for 1 mole of the mixture, placed in a Teflon container, and dried at room temperature to obtain a transparent gel-like molded film. Next, this was fired for 2 hours at 1i o o o o °C to form (a) YAlO3: Ce + Y3・#s
Olt' Ce (b) YsAl
s Olt: Co and (c) Y2 A140g:
A highly translucent phosphor film consisting of a cerium yttrium aluminate phosphor having a compositional formula of Ce was obtained. This was confirmed by X-ray diffraction.

Example 2 Yttrium isogloboxide, aluminum isogloboxide, and cerium isogloboxide in a molar ratio of 3:
The mixture was mixed in a benzene solution with a J1 ratio of 5:5×10 ” and refluxed at a temperature of 82° C. for 4 hours, followed by adding water for hydrolysis to obtain a mixture of yttrium sol, aluminum sol and cerium sol.

When this was gelled and fired in the same manner as in Example 1, a highly transparent phosphor film consisting of a cerium-activated yttrium aluminate phosphor having the composition formula YB At50H:Ce was obtained. This was identified using X-ray diffraction.

Example 3 Potassium metal was reacted with excess inglobil alcohol in a nitrogen stream to produce potassium isogloboxoxide (l C3
H? To this was added aluminum isogloboxide in an equimolar amount to the metal potassium and refluxed for 2 hours to synthesize potassium aluminum isogloboxoxide (KM (1
-OC, H7) 4) k was synthesized. This was added to an alcoholic solution of yttrium isoglobil chloride and an alcoholic solution of cerium chloride and refluxed for 4 hours to produce yttrium-cerium-aluminum isoglopoxide (Y
``Ce(N(1-0C3H?)4]s)k was synthesized.The reaction by-product α was separated after replacing the solvent with benzene.

Excess distilled water was added to the obtained alkoxide and subjected to Ra to obtain a composite yttrium aluminum cerium sol.

This was gelled and molded in the same manner as in Example 1.
By firing at 00℃, the composition formula Y3Ale 0!
2: A highly transparent phosphor film made of a cerium-activated yttrium aluminate phosphor was obtained. This was confirmed by X-ray diffraction.

Example 4 A cigadolinium sol was obtained in the same manner as in Example 1, using high purity gadolinium oxide as a substitute for the high purity yttrium oxide starting material.

When this gadolinium sol, aluminum sol, and cerium sol were mixed in a molar ratio of 3:5:5X1 (11), formed by gelation, and further fired, cerium-activated gadolinium aluminate with a composition ratio of GdlAl5O12:Ce was obtained. A highly transparent phosphor film consisting of phosphors was obtained, which was identified by X-ray diffraction.

Example 5 Yttrium aluminum cerium isoglopoxide (Y-Ce[,
41! To (1-0(C3H7)4)11), 0.4 mol of aluminum isoglopoxide CM (10CsH7)3') was added per 1 mol of the mixture and mixed thoroughly by refluxing for 4 hours, followed by hydrolysis. , Sol is a friend.

This sol was gelatinized and then baked at 1000° C. for 2 hours to obtain a highly transparent phosphor film consisting of a cerium-activated yttrium aluminate phosphor having the composition formula Ys#5OI2:Ce. This was identified by X-ray diffraction.

Example 6 Yttrium aluminum sericum isoglopoquine (Y-Ce[A
t (i −0CsHq )4 ]s ), 0.2 mol of yttrium isogloboxoxide (y
(i 0CsHy)s ) was added and thoroughly mixed by refluxing for 18 hours, followed by hydrolysis to obtain a sol.

After gelatinizing this sol and baking it at 1000°C for 2 hours, a highly transparent phosphor film consisting of a cerium-activated yttrium aluminate phosphor having the composition formula YAlO3:Ce (hexagonal) was obtained. . Also, the top is self-gel 1260
After baking at .degree. C. for 2 hours, a highly transparent phosphor film consisting of a cerium-activated yttrium aluminate phosphor having a compositional formula of yno: ce (orthorhombic, perovskite type) was obtained. These things were identified by X-ray diffraction.

Example 7 Europium sol was obtained in the same manner as in Example 1. This europium sol was mixed with the yttrium sol obtained in Example 1 at a molar ratio of 1:5XIO-3, gelled, and then baked at 1100°C for 2 hours, resulting in a composition formula of Y203:
A translucent phosphor film consisting of a red-emitting phosphor designated Eu was obtained.

Example 8 Silica gel, terbium sol, and europium sol were obtained in the same manner as in Example 1. The various sols obtained above, the yttrium sol obtained in Example 1, and the cerium sol were mixed so as to demonstrate the lack of gold. Y2SiO5: Eu5
Y2StO, :Tb.

Y2S405:Ce (However, Eu, Tb, Ce are 5
X 10. 'mol) 1200 after gelling these sols
After firing at .degree. C. for 2 hours, a phosphor having the above-mentioned formula was obtained. This shows red, green, and blue, respectively.

Example 9 The yttrium sol in Example 7 was gelled to obtain 8μ spherical yttrium oxide.

This surface was coated with europium sol, terbium sol, and cerium sol to a thickness of 0.5μ, and after gelation,
It was fired at 000°C. After firing, the sulobium, terbium, and cerium were diffused into the IJium and became highly translucent phosphor particles. This was identified by X-ray diffraction.

Attachment of Procedural Amendment March 1, 2005 Mr. Kazuo Wakasugi, Commissioner of the Japan Patent Office 1 Indication of the case Japanese Patent Application No. 11725/1982 2 Name of the invention Method for forming a highly transparent fluorescent film 3 Case of the person making the amendment Relationship with Patent applicant name: Kasei Onotonics Co., Ltd. 4 Agent address: Mori Building, 40 Toranomon, 5-13-1, Toranomon, Minato-ku, Tokyo Specification and power of attorney 6 Contents of amendment Shine.

Procedures Amendment 58 cans May 13th Director of the Japan Patent Office Kazuo Wakasugi 1 Indication of the case Japanese Patent Application No. 11725/1982 2 Name of the invention Method of forming highly translucent fluorescent film 3 Make amendments Relationship with the patent applicant name: Kasei Optonics Co., Ltd. 4 Agent address: Mori Building, Toranomon 4-chome, 5-13-1, Toranomon, Minato-ku, Tokyo Column 6 of the detailed description of the invention in the specification, Contents of the amendment (1) ) "High translucency of aluminate" on page 7, line 10 of the specification is corrected to "high translucency of aluminate".

+21 Akira J41, 1L8ffl 6th row and 121st
Correct "500°C" in the 9th line to "300°C".

+3+ r A1203S on page 15, line 11 of the specification
Correct i02 J to r Al2O3,5i02 J.

Claims (1)

[Claims] By hydrolyzing a metal alkoxide, an organic acid metal compound, or a metal salt containing each element of the matrix constituent elements of the phosphor and each element of the activator constituent elements of the phosphor, the above-mentioned fluorescent light can be produced. A highly transparent method characterized by obtaining a sol containing each element necessary for body composition, then placing the sol in a container of the desired shape, gelling it to form a film, and then firing it at 300°C to 1300°C. Method for forming a photofluorescent film.