JPH01274354A - Ultraviolet-ray excitation luminescent tube - Google Patents

Abstract

PURPOSE:To improve the brightness of a luminescent substance effectively by using a composite in which a phosphor and a fluoride of alkali earth metal are mixed or fused together as the luminescent substance. CONSTITUTION:A luminescent composite containing particles having the phosphor and fluoride of alkali earth metal thermally fused or attached thereto in a fluorescent screen. In this case, the added fluoride of alkali earth metal is not a component constituting the parent body of the phosphor, but present in a state mixed or fused with the phosphor. As the fluoride of alkali earth metal, at least one fluoride of Ba, St, Ca and Ma is used. The content of the fluoride of alkali earth metal in the luminescent composite generally ranges from 1 to 95% by weight. To improve the luminescent characteristic and coating characteristic, the phosphor is suspended in an aqueous solution to which either of a salt of water-soluble fluoride compound or a salt of alkali earth metal, and the other fluoride is added thereto to obtain a homogeneous mixture of precipitates of the phosphor and the alkali earth metal fluoride.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an ultraviolet-excited luminous tube (hereinafter simply referred to as a fluorescent lamp) having an ultraviolet radiation source such as a fluorescent lamp and a fluorescent screen that emits light upon receiving the ultraviolet light. ) regarding. More specifically, it is a luminescent composition consisting of a phosphor and an alkaline earth metal fluoride, which maintains extremely high brightness even though it contains a large amount of such non-luminescent substances, and is extremely inexpensive. The present invention relates to a fluorescent lamp used as a fluorescent film.

(Prior Art) Phosphors usually have a special ability to convert invisible excitation energy into visible light, so they are more expensive than simple chemical materials. Especially in recent years,
In order to satisfy various properties, large amounts of rare earth elements and base metal elements have come to be used as raw materials. Therefore, various restrictions arise in its use due to price, and the problem arises that the optimum phosphor cannot always be used for the purpose. Therefore, there is a strong desire to reduce the cost of such phosphors.

On the other hand, technologies for this purpose that are close to the present invention include:
For example, British Patent No. 803328 describes that in a fluorescent lamp, the amount of fluorescent material used can be reduced by interposing a layer of a material with good ultraviolet reflectance between the support and the fluorescent material. In addition, as an improvement of this technology, USP No. 4069441 describes barium sulfate,
A film made of a mixture of a phosphor and a white substance with low ultraviolet absorption such as amorphous calcium phosphate or magnesium oxide is provided on the glass tube side, and a film made only of the phosphor is laminated thereon, and the film is made of the above mixture. A gas discharge lamp is disclosed in which the membrane has a structure in which the ratio of the white substance to the phosphor increases toward the glass tube side. Furthermore, Japanese Patent Laid-Open No. 128452/1983 is known as a related technique.

Similarly, a simple mixture of a phosphor and a white pigment depending on the specific use (such as an X-ray image conversion screen) is classified as USP.

Publication No. 4039840, Japanese Patent Publication No. 55-5478,
It is disclosed in Japanese Patent Application Laid-Open No. 55-148447.

Also, for example, Japanese Patent Publication No. 59-45708, Japanese Unexamined Patent Publication No. 55
Fluoride-based phosphors of alkaline earth metals (that is, phosphors containing alkaline earth metal fluorides as one of the base materials) are also known, as disclosed in Japanese Patent No. 12145 and the like. These phosphors contain europium cerium, terbium, etc. as activators.

It emits ultraviolet or blue light depending on the excitation energy.

The mixture of the above-mentioned phosphor and the white substance has a remarkable reduction in luminance from a practical level, and in order to further reduce this reduction or to produce other effects, it is necessary to use the methods disclosed in the above-mentioned publications. Complex means such as forming a special layer structure are required, and the amount of the white substance used is often limited to a few percent by weight or less.
No. 6 discloses that a white substance such as BaF2 is used as a flux, removed by cleaning after firing, and used as a phosphor for a projection tube.

As mentioned above, none of the conventional techniques has been able to reduce the luminance of luminescent substances and reduce the price of these luminescent substances significantly (problems to be solved by the invention). In order to solve this problem, the invention proposed a luminescent composition made by fusing a phosphor and an alkaline earth metal sulfate (
Patent Application Sho Elf-298873), Shikashita et al., Ba
The above-mentioned sulfate materials, typified by SO4, are highly caloric and easily decompose when fired at high temperatures, and for this reason, the original effects of sulfate combinations may not be fully achieved.

The purpose of the present invention is to hardly reduce the luminance of the luminescent material,
The object of the present invention is to provide a fluorescent lamp using a luminescent composition in a fluorescent film, which can improve luminance in some cases and significantly reduce the cost of the luminescent material.

As a result of intensive research on the combination of low-cost non-luminescent materials and expensive phosphors, the inventors of the present invention have found that by using a composition in which a phosphor and an alkaline earth metal fluoride are mixed or fused together as a luminescent substance, the above-mentioned The inventors have discovered that the above objects can be achieved, and have arrived at the present invention.

(Means for Solving the Problems) According to the present invention, there is provided an ultraviolet-excited luminous tube characterized in that the fluorescent film contains a luminescent composition comprising a phosphor and an alkaline earth metal fluoride.

Further, according to the present invention, there is provided a fluorescent lamp characterized in that the luminescent film contains a luminescent composition made of a mixture of a phosphor and a heat-treated alkaline earth metal fluoride.

Furthermore, according to the present invention, there is provided a light-emitting composition containing particles formed by thermally fusing or adhering a phosphor and an alkaline earth metal fluoride (hereinafter such a state is representatively referred to as fusing). Provided is a fluorescent lamp characterized in that the fluorescent film contains the following.

In the present invention, the added alkaline earth metal fluoride does not react with the phosphor and become a component constituting its matrix, but exists in a mixed or fused state with the phosphor. According to X-ray diffraction, the luminescent composition has confirmed the respective X-ray patterns of phosphor and fluoride. Although any conventional phosphor can be used as the phosphor used in the present invention, Preferred are phosphors that have low reactivity with alkaline earth metal fluorides at temperatures between 1000°C and 1000°C. In addition, from a practical point of view, phosphors containing at least one of rare earth elements and base metal elements are particularly preferred in terms of the effect of reducing the material cost of the luminescent material, and phosphors containing large amounts of these elements are particularly preferred. From this point of view, oxides containing the above elements (oxides, oxysulfides, silicates, aluminates, phosphates, vanadates,
For example, among the phosphors for lamps that are in practical use in large quantities, rare earth oxide phosphors (borate, etc.) are the most expensive and contain europium, an oxide phosphor, as an activator. Formula Ln2O3: Eu phosphor, where L
When the present invention is applied to fI (at least one of Y, Gd, La, and Lu), the effect is extremely large.

Further, the alkaline earth metal fluoride used in the present invention is a fluoride of at least one element of barium, strontium, calcium, and magnesium, and representative examples thereof include BaF2, SrF2, and GaF2. In addition, the above-mentioned alkaline earth metal heptafluoride may contain a small amount of other elements, and particularly when it contains scandium or lithium as a fluoride, good results are shown.
These alkaline earth metal fluorides are usually used after being deagglomerated with a sieve to remove small particles before being mixed with the phosphor.

The mixing of the two may be sufficiently carried out in a mortar or mill, but either dry or wet methods may be used.

The content of alkaline earth fluorides in the luminescent composition according to the invention is usually in the range 1 to 95% by weight, in particular 5 to 9% by weight.
A range of 0% by weight is preferred, and a range of 5 to 60% by weight is further recommended.

In addition, in order to improve the performance of the luminescent composition, a mixture of a phosphor and an alkaline earth metal fluoride is added at a concentration of 550 to 1500%.
C., preferably 700 to 1300 C. This mixture is placed in a heat-resistant container and fired at a temperature below the melting point of the raw material phosphor and fluoride for several tens of minutes to several hours. The atmosphere during firing is the atmosphere normally used in manufacturing phosphors.

Further, when mixing the above raw materials, it is recommended that a fluxing agent be added as appropriate. In particular, it is recommended to add one of the compounds containing at least one of barium, phosphorus and boron. By including such a fluxing agent, a luminescent composition having good brightness and good granularity can be obtained.

Further, a method for producing a luminescent composition having a narrow particle size distribution in order to improve luminescent properties and coating film properties as a fluorescent film is, for example, as follows. A phosphor is suspended in an aqueous solution containing either a fluorine compound salt or an alkaline earth metal salt, both of which are soluble in water, and the other fluoride or alkaline earth salt is added to form a phosphor. A homogeneous mixture of precipitate and alkaline earth metal fluoride is obtained.

Water-soluble fluorine salts include HF, NH4HF2, NH
4F.

Examples include NaHF2 and NaF, and alkaline earth metal salts include nitrates and halides other than fluorides, which are selected with particular consideration to the acid resistance properties of the phosphor. The order of addition in the above precipitation reaction may be light for either the fluoride salt or the alkaline earth salt.When forming a precipitate, the solution is usually stirred, and the stirring conditions and concentration of the solution are The particle size can be changed by adjusting the addition rate, etc.

In this way, by generating a mixture of fluorescence and alkaline earth fluoride precipitates, it is possible to obtain a precipitate in which each component is well dispersed, thereby making it possible to obtain desired particle size characteristics and luminescent properties. Also, a sufficient luminescent composition can be stably obtained.

The thus obtained precipitate is placed in, for example, a heat-resistant container and fired to fuse the phosphor and the alkaline earth metal fluoride, and this firing is carried out under the same firing conditions as above.

In the production method of the present invention, instead of the alkaline earth metal fluoride, a full fat substance that can be converted into the alkaline earth metal fluoride in the calcination may also be used. The term fluoride salt is intended to include such precursors. Such precursors include inorganic salts such as alkaline earth metal carbonates and nitrates, or combinations of organic salts (such as acetates, citrates, oxalates) and fluoride salts (such as ammonium fluoride). A combination is exemplified.

Furthermore, in the present invention, the luminescent composition obtained by mixing a fluoride of an alkaline earth metal that has been heat-treated in advance with a phosphor exhibits a good effect particularly in terms of brightness. For example, fluoride of 5500 to 12
The upper limit of this temperature can be raised to a higher temperature (for example, 1500°C) by shortening the treatment time. This is preferably carried out so that the particle size usually has a median of 2 to 40 mm, preferably 3.
It is carried out so that it is in the range of ~20 liters. Among the fluorides treated in this way, fluorides containing barium are particularly preferred.

Note that the above heat treatment or the above fusion may be realized by performing the above baking at a high temperature in the fluorescent lamp manufacturing process in which the phosphor and the fluoride are mechanically mixed, applied to the inside of a glass tube, and baked. Needless to say.

As mentioned above, light emission according to the present invention! The luminescent composition emits extremely high luminance when exposed to ultraviolet light, and thus fluorescent lamps made according to conventional methods using this luminescent composition are also extremely useful. In particular, the luminescent composition of the present invention has high brightness and can significantly reduce the cost of phosphors containing rare earth elements and base metal elements, so it can be put to practical use in high color rendering fluorescent lamps that use large amounts of such phosphors. things are recommended.

That is, a blue luminescent material whose fluorescent film of a fluorescent lamp has a peak emission wavelength in the range of 430 nm to 475 ns, 520 nm to 475 ns;
A green luminescent substance having a peak emission wavelength in the range of 560 nm and a red luminescent substance having a peak emission wavelength in the range of 595 nm to 630 nm, and at least one of the luminescent substances is composed of the luminescent composition according to the present invention. be. As the phosphor contained in the blue light-emitting substance, a divalent europium-activated calcium chloroborate phosphor (Example C
a2Bs0gCl:Eu2''), divalent noeuropium activated alkaline earth metal aluminate phosphor (Example B
aKg2Al+602z:Eu2"), divalent europium-activated alkaline earth metal halophosphate phosphor [e.g. aM■3(PO4)2・bM"cI2:Eu:" (where M■= Cs, Sr, Ba, 1 ≦a/b≦3)]
,, h Examples of the phosphor contained in the recording color luminescent material include cerium- and terbium-activated lanthanum phosphate-based phosphors (e.g. La
POJ (2Ce, Tb), cerium-terbium activated alkaline earth metal borate fluorescence [NnM 0-132.03: Ce, Tb (however, L M = 14g, Zn.

0<n≦2), GdMgBs0+o:Ce
, DBL, Terbium-activated alkaline earth metal cerium
Armin fl! ■ With I salt ■ Photobody [Example (C:e, Tb) M Aft 1019
(However, M■-11!g.

Zn)], cerium-terbium activated rare earth silicate phosphor [e.g. Ln2SiO< :Ce, Tb (however, Ln
= Y, Gd, La)], and the phosphor contained in the red light-emitting substance is a europium-activated rare earth oxide phosphor [e.g. Ln2O3:Eu (Ln = Y, Gd, La)].
] are recommended as representative examples. Furthermore, a blue-green luminescent material having a peak emission wavelength in the range of 480 nm to 500 nm may be added for color rendering.The phosphor contained in this blue-green luminescent material is divalent europium-activated strontium aluminum. nate phosphors [e.g.
4sro・nAl2O3:Eu” (5≦n≦8)
, divalent europium-activated alkaline earth metal borophosphate phosphor [e.g.
2O3:Eu2・(However, M■ = Ca, Sr, Ha
, 175≦m≦2.30, 0.05≦n≦
0°23)] is recommended as a representative one.

By using the luminescent composition of the present invention in which at least one of the above-mentioned phosphors and an alkaline earth metal fluoride are mixed or fused together, the amount of the above-mentioned phosphors used can be significantly reduced. For this purpose as well, it is recommended that the luminescent composition according to the present invention contains a rare earth element as a host constituent element as the phosphor, or an oxide phosphor containing a large amount of a rare earth element as an activator. That is, such phosphors include europium activated rare earth oxide phosphors, cerium-terbium activated rare earth silicate phosphors, and the like.

Moreover, the surprising effects of the luminescent composition according to the present invention include not only improving the brightness of the fused phosphors, but also improving the brightness of other unfused phosphors mechanically mixed with the luminescent composition of the present invention. For example, the luminescent composition of the present invention (Ln, Eu) has the effect of improving luminous efficiency on the body.
The high color rendering fluorescent lamp of the present invention has a phosphor film obtained by mixing a mixture of No. 203 and an alkaline earth metal fluoride with the green-emitting phosphor and the blue-emitting phosphor. To obtain the same emission color as a conventional high color rendering fluorescent lamp that does not contain fluoride, (LnEu)
Not only the amount of the 203 phosphor used can be reduced, but also the amount of other green-emitting phosphors and blue-emitting phosphors can be reduced at the same time. This example will be illustrated by way of example. From this fact, it can be seen that in the high color rendering fluorescent lamp of the present invention, the fluorescent composition can be prepared most stably or more easily in combination with an alkaline earth metal fluoride. It is recommended that you choose your body accordingly. A typical example of such a phosphor is a europium-activated rare earth oxide phosphor that emits red light. Therefore, the examples shown below will be shown regarding fluorescent lamps using the luminescent composition according to the present invention using this phosphor, but the present invention is not limited thereto in any way.

Hereinafter, the present invention will be explained in more detail with reference to some examples.

Example 1 Phosphor Y2O3: Eu (sample A) 50 parts by weight,
After thoroughly mixing 50 parts by weight of reagent grade barium fluoride (BaF2), the mixture was filled into a heat-resistant container and heated to 1200°C in air.
The composition was baked for 2 hours at 0.000 mL, then washed and dried to obtain a luminescent composition of the present invention. (Sample B).

In addition, phosphor Y2O3: Eu and 2, barium chloride 5
A mixture of 0 tm parts was prepared. (Sample C)
.

A fluorescent lamp was prepared using the E thermostat sample, and the luminance and color of the emitted light were measured (hereinafter, this measurement is referred to as ultraviolet measurement). Indicating the luminance of the products of the present invention, no shift in luminescent color from the original phosphor was observed in any of the samples.

Example 3 Phosphor Y703: The luminance of a product of the present invention manufactured in the same manner as Sample B except for changing the mixing ratio of Eu and barium fluoride in Example 1 is shown.

Example 4 Equivalent parts by weight of each phosphor and barium fluoride were sufficiently mixed, then baked in air at 900° C. for 4 hours in a heat-resistant container and finished with a sieve to obtain a luminescent composition according to the present invention.

The luminance of the fluorescent lamps of the phosphors of the present invention (fired ones and simply mixed ones without firing) is shown below. Regarding the emission color, there was almost no color shift from the original phosphor.

Example 5 The brightness of each phosphor was compared in the same manner as in Example 4 except that the atmosphere was made reducing. There was almost no shift in the 0 color tone.

i=l, i=2. i=3 as described above in Example 6 The following results were obtained in the same manner as in Example 5 except that the firing temperature condition was changed to 700°C.

Examples 1, 4, 5 above. As shown in 6 and 6, the desired effect can be obtained even when using a light-emitting composition in which a phosphor and an alkaline earth metal fluoride are simply mixed.

Example 7 Samples were produced in the same manner as in Example 5, except that the phosphor was Y2O2S:Eu and Sample Y), and the barium fluoride was changed to special grade reagents calcium fluoride and strontium fluoride.

(Samples V and W).

Next, strotium acetate (Sr(CH3COO)z
Make 47 parts by weight of 1/2H20) into a 10% aqueous solution, add this and 28 parts by weight of the phosphor to 10 times the volume of water, and add 25 parts by weight of ammonium hydrogen 77ide to this as a 5% aqueous solution while stirring well. A product of the present invention (also referred to as a sample) was obtained by gradually adding strontium fluoride of the obtained phosphor, and firing the resulting phosphor using the precipitate of strontium fluoride as a raw material.

There wasn't.

Example 8 Luminescent composition Y2O3:Eu-BaF shown in Example 1
;+(x/y=0.64810.347) red luminescent component 40 parts, LaPO4:Ce, Tb
35 parts by weight of the green emitting component of the phosphor (x/y-0,35910,547) and 25 parts by weight of the blue emitting component of the Ga2Bs04C1:Eu phosphor (X/7 = 0.13410.0134) were thoroughly mixed. A coating solution is prepared using the mixed phosphor, and after coating it in a glass tube so that the coating amount of the mixed phosphor is approximately 3.5/c2, the high color rendering phosphor of the present invention is coated using a conventional method. manufactured a lamp. This fluorescent lamp has a luminescent color (x / y = 0.353
10.375) exhibits a high color rendering property of white light emission, and the brightness is the same as that of the fluorescent lamp (1), which does not use BaF2.
1 degree = 100%) showed 99 taro.

Example 9 BaF was preliminarily calcined at 900°C for 4 hours (in air at 12°C in a reducing atmosphere), and after being sieved, it was mixed with Y7C]2S:Eu phosphor, etc. using a luminescent composition obtained in Eastern Europe. I made a fluorescent lamp. (Samples Z1 and Z2). For comparison, a fluorescent lamp was prepared by simply mixing the BaF reagent and the phosphor (Sample Z3).

Example 10 Comparison of electron beam brightness at 1 nA/cm2.12kV Mixture product

Claims (3)

[Claims] (1) An ultraviolet-excited luminous tube characterized in that a fluorescent film contains a luminescent composition comprising a phosphor and an alkaline earth metal fluoride. (2) An ultraviolet-excited luminous tube characterized in that the fluorescent film contains a luminescent composition made of a mixture of a phosphor and a heat-treated alkaline earth metal fluoride. (3) An ultraviolet-excited luminous tube characterized in that the fluorescent film contains a luminescent composition containing particles formed by thermally fusing or adhering a phosphor and an alkaline earth metal fluoride.