JPH04117B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to inorganic luminescent materials. More specifically, the present invention relates to a phosphor made of a composite fluorine compound glass containing uranium as a guest substance, which emits fluorescent light upon receiving excitation energy from ultraviolet irradiation or the like.

Prior Art A fluorescent substance absorbs energy when externally applied and emits the energy to the outside in the form of light, and this light is well known as fluorescence. Energy can be given to the phosphor in various ways, such as light, electron beam, ion irradiation, pressurization, and heating.

Substances that emit such fluorescence include NaCl
Alkali halides such as, single semiconductors such as Si,
Compound semiconductors such as ZnS, CdS, and CaAs, metal oxides such as Al garnet, and oxyacids such as ZnSiO ₄ have been well known and are used in various fields, such as color cathode ray tubes, radar tubes, electroluminescent materials, Fluorescent display tube, alpha or beta
It has been widely used in line detectors, solid-state lasers, etc.

Inorganic fluorescent materials contain a host (base material) and a guest (activation ions, such as transition metal ions such as Cr ³⁺ and Ni ²⁺ , rare earth element ions such as Nd ³⁺ and Ho ³⁺ , and U ³⁺ ). Actinide ions, etc.) are known, and by appropriately selecting the activated ions, it is possible to obtain a desired luminescent color and achieve high efficiency.

Examples of the phosphor activated with uranyl ions include the strontium zinc pyrophosphate phosphor (SrZnP ₂ O ₇ :U) disclosed in the invention disclosed in Japanese Patent Publication No. 49-38432, or the invention disclosed in Japanese Patent Publication No. 48-30832. The disclosed barium pyrophosphate phosphor (BaP ₂ O ₇ :U) and the like are already known. With these phosphors, UV irradiation, etc.
Spectrum extending from 500nm to 600nm (green)
However, the drawback is that the fluorescence varies greatly depending on the manufacturing conditions of the phosphor, such as the method of mixing raw materials, impurities, firing time, firing temperature, firing atmosphere, etc.

In addition, the dopant U has the characteristic of emitting strong fluorescence in a long wavelength range of 2.5 to 2.6 μm compared to other ions, but conventional fluorophores do not emit fluorescence in this wavelength range due to absorption in the matrix. The drawback was that light could not be observed.

Problems to be Solved by the Invention As mentioned above, conventionally known phosphors activated with uranyl ions and phosphors using uranium as a dopane exhibit fluorescence that varies greatly depending on various manufacturing conditions. In some cases, the fluorophore could no longer be observed due to absorption by the matrix.

Therefore, developing a new phosphor that does not exhibit such drawbacks is of great significance in increasing the reliability of the phosphor and expanding its field of application.

Therefore, the purpose of the present invention is to
The object of the present invention is to provide a phosphor that emits green fluorescent light over a wavelength range of 500 nm to 600 nm.

Another object of the present invention is to provide a phosphor that emits infrared light in the 2.2-2.6 μm band by xenon lamp excitation or the like.

Measures to Solve the Problems In view of the current state of phosphors containing uranium or uranyl ions, various studies and research are being carried out to develop new uranium-containing phosphors that do not exhibit the above-mentioned drawbacks. Recently, as a glass material for infrared fibers, for example, Izumiya supervised, New Glass and Its Physical Properties, Chapter 16, p. 618-620, Management System Research Institute, 1984, M: Mater by Poulain et al.
Res, Bullb., 10 , (1975) 243; Mitachi et al. Jpn.
The composite fluorine substances disclosed in J.Appl.Phys., 20 , (1981) L337, and Miyashita's Applied Physics, 52 , (1983) 316 are extremely useful as a matrix for the desired phosphor. They discovered this and completed the present invention.

That is, the phosphor of the present invention is characterized by containing a composite fluorine compound glass as a matrix and uranium as a dopant.

The composite fluorine compound glass useful as a matrix in the phosphor of the present invention has a composition represented by the following general formula.

(a)……(ZrF ₄ ) _a −(M()F) _b −(M()F ₂ ) _c −(M()F ₃ ) _d −(M()F ₃ ) _e where M() is Li or Na, M() is Ba or Ca, M() is Al, M() is Y or lanthanide, and a, b, c, d and e represent mol%,
The respective values are preferably within the following ranges: 50≦a≦70 0≦b≦30 20≦c≦40 0≦d≦20 0≦e≦20 In the glass of general formula (a), M ()F,M
()F ₂ , M()F ₃ and M()F ₃ can be used alone or in combination of two or more.

(b)... (BaF ₂ ) _a ′−(CaF ₂ ) _b ′−(YF ₃ ) _c ′ −(AlF ₃ ) _d ′ where a′, b′, c′, and d′ represent mol%. represents,
The values are preferably within the following ranges: 33≦a′+b′≦47 6≦c′≦28 36≦d′≦53 The phosphor of the present invention is a composite fluorine compound as described above. This is a phosphor composition that uses glass as a host and uranium as a guest substance, and emits fluorescent light such as green light or infrared light when exposed to ultraviolet light or the like.

Here, in the above composite fluorine compound glass, by setting the mole percentages a to e and a' to d' of each composition within the above ranges, it is possible to obtain a phosphor with the desired excellent characteristics. becomes. Further, by setting the composition of the composite fluorine compound glass as described above, it is possible to obtain a high-quality glass that does not cause crystal precipitation under normal glass manufacturing conditions.

Further, the phosphor according to the present invention can be produced according to a generally known method for producing composite fluoride glass. That is, for example, a raw material fluoride and a uranium source as a dopant, such as UF,
After weighing and mixing UO ₂ (CH ₃ CO ₂ ) _{2.2H 2} O, etc., it is heated to 400℃ in a platinum crucible or gold crucible.
It can be produced by heating at a temperature in the range of 500°C, then heating it further to about 900°C to melt it, pouring it into a mold, cooling it, and forming it into a glass rod or the like.

Function As already mentioned, it is well known that uranium in glass or crystals emits fluorescence under certain conditions when excited by ultraviolet light. For example, in addition to phosphates such as SrZnP ₂ O ₇ :U and BaP ₂ O ₇ :U mentioned above, LiF, NaF, CaF ₂ , BaF ₂ ,
Fluorescence is also observed in fluorides such as SrF ₂ .

However, according to the present invention, ZrF ₄ -BaF ₂ -M, whose main component is ZrF ₄ , which has been developed as an infrared fiber material and whose transmission loss has been reduced recently, has been developed as an infrared fiber material.
_Composite fluorine compound glasses such as
No. 4 (1983) 315, etc.) as a host and doped uranium as a guest. It becomes possible to obtain products with

General formula () using the fluorine compound glass of (a) as a matrix: (ZrF ₄ ) _a −(M()F) _b −(M()F ₂ ) _c −(M()F ₃ ) _d −(M()F ₃ ) _e :U……() For the phosphor represented by, the composition ratios a, b, c,
When d and e are in the composition range shown above, the composite fluoride forms a stable glass phase, and when this is irradiated with ultraviolet rays or visible light from a xenon lamp etc. green (ranging from 480nm to 620nm, generally 6
It emits fluorescent light (which gives the fluorescent spectrum of a book), or it emits infrared fluorescence in the 2.2 to 2.6 μm band.

Therefore, the phosphor according to the present invention is not only a green and infrared band phosphor, but also a composite fluoride host (sample thickness t=
4mm) has a wide wavelength band (0.2mm) as shown in Figure 3.
~7.5μm), so 2.2~2.6μm
It can also be advantageously used as a phosphor glass fiber.

Since the phosphor according to the present invention has the luminescent properties as described above, it can be used for color correction of low-pressure, medium-pressure, and high-pressure mercury discharge lamps and cathode ray tube screens.
It can be used in devices for detecting and measuring the intensity of ion and X-ray radiation, and can also be advantageously used in applications requiring high-intensity radiation, such as improved copying techniques for materials of various colors.

Furthermore, according to the phosphor of the present invention, the fluorescence does not change depending on the manufacturing conditions of the phosphor, as seen in the conventional method, but on the contrary, as shown in FIG. Since it exhibits a phosphor intensity that is directly proportional to the amount of uranium as a substance, it can also be used as a standard sample for quantitative analysis of uranium concentration in various materials.

Examples Hereinafter, the phosphor of the present invention will be explained in more detail with reference to Examples (manufacturing examples), but the scope of the present invention is not limited in any way by the following Examples.

Example 1 Fluorides as starting materials; BaF ₂ , ZrF ₄ , GdF ₃ ,
AlF ₃ and UF ₄ at 32, 60, 4, 4 and 3 respectively
×10 ^-5 mol% weighed, mixed, and added to this NH ₄ F・HF
was added in an amount of 20% by weight. This addition of NH ₄ F・HF is
This is done to fluorinate trace amounts of oxides contained in the starting material during the next heat treatment. Place this in a platinum or gold crucible and heat to 400℃ to 500℃.
It was heat-treated for about 2 hours. After that, the temperature was raised to 900℃,
After completely melting, the temperature was maintained for 1 to 2 hours.

The molten glass was then poured into a brass mold with an inner diameter of 10 mm and cooled to form a glass rod.

Figure 1 shows the fluorescence spectrum when the phosphor of the present invention produced as described above was irradiated with ultraviolet light of 280±5 nm, and Figure 2 shows the fluorescence spectrum when the wavelength of 518 nm in the same spectrum was fixed. , which shows the excitation spectrum obtained by scanning the excitation wavelength.

Also, at a wavelength of 2.2 to 2.6 μm, ⁴ I _11/2 of U ³⁺
→ ⁴ I _9/2 emission associated with the transition was observed.

Example 2 ZrF ₄ (60)−BaF ₂ (32)− as a glass host
YF ₃ (4)-AlF ₃ (4 mol%) was used, and U was added to it.
A glass sample containing 100 ppm (weight%) was prepared in the same manner as in Example 1.

As in Example 1, when irradiated with ultraviolet light of 280±5 nm, the fluorescence spectrum shown in FIG. 1 was observed.

Also, at a wavelength of 2.2 to 2.6 μm, ⁴ I _11/2 of U ³⁺
→ ⁴ I _9/2 emission associated with the transition was observed.

Example 3 BaF ₂ , CaF ₂ , YF ₃ and AlF ₃ as starting materials
Weighed 20, 20, 17 and 43 mol% of each, to which was added 1×10 ^-6 mol% of UO ₂ (CH ₃ CH ₂ ) _{2.2H 2} O, and 20% by weight of NH ₄ F.HF. Mixed.
Using this, a glass rod was obtained in substantially the same manner as in Example 1.

When the fluorescence spectrum was measured in this case as well, a fluorescence spectrum almost the same as that in Example 1 was observed. That is, the wavelength is 518 nm and
Fluorescence was observed at 2.2 to 2.6 μm, showing a constant intensity that was not affected by manufacturing conditions.

Figure 4 shows the relationship between the fluorescence intensity at a wavelength of 518 and the uranium concentration when irradiated with ultraviolet rays at a wavelength of 280 nm for several samples in which glass having the composition of Example 2 was doped with uranium at different concentrations. It is something. From the results shown in FIG. 4, it can be seen that there is a linear relationship between the amount of uranium added and the fluorescence intensity.

Effects of the Invention As explained above, according to the present invention, by employing fluoride glass as a matrix and combining it with uranium as a phosphor ion, the concentration of uranium added is proportional to the concentration of uranium. A phosphor with an independent fluorescence intensity is obtained. This has the advantage that it can be used as a standard sample in quantitative analysis of uranium concentrations in various materials.

In addition, the high light transmittance of fluoride glass in a wide wavelength range of 0.2 μm to 7.5 μm, combined with U, which has fluorescence in the 2.2 to 2.6 μm range, is a new type of light that enables the amplification of transmitted signals by light. It has the advantage of being able to provide fibers.

Furthermore, it can be applied to the same application fields as conventional uranium-containing inorganic phosphors, and its characteristics do not depend on manufacturing conditions, making it possible to create various products using phosphors that are more stable and reliable. It becomes possible to provide

[Brief explanation of drawings]

Figure 1 shows the wavelength of 280 nm of the phosphor according to the present invention.
FIG. 2 is a diagram showing the fluorescence spectrum due to ultraviolet excitation of ±5 nm, FIG. 2 is a diagram showing the excitation spectrum when the wavelength is fixed at 518 nm, and FIG _{. 3} is a diagram showing the fluorescence spectrum when the wavelength _is fixed at 518 nm. FIG. 4 is a graph showing wavelength characteristics of light transmittance of glass, and _FIG .
It is a graph showing the relationship between fluorescence intensity at a wavelength of 518 nm and doped uranium concentration of _CaF2 - _YF3 - _AlF3 -based glass.

Claims (1)

[Scope of Claims] 1. A phosphor comprising a fluorine compound glass satisfying the following formula as a matrix and uranium as a dopant. (ZrF ₄ ) _a − (M()F) _b − (M()F ₂ ) _c − (M()F ₃ ) _d − (M()F ₃ ) _e where M() is Li or Na, M() is Ba or Ca, M() is Al, M() is Y or lanthanoid, and a, b, c, d and e represent mol%,
Each value is within the following ranges: 50≦a≦70 0≦b≦30 20≦c≦40 0≦d≦20 0≦e≦20 2 Fluorine as a base that satisfies the following formula A phosphor characterized by containing a compound glass and uranium as a dopant. (BaF ₂ ) _a ′−(CaF ₂ ) _b ′−(YF ₃ ) _c ′ −(AlF ₃ ) _d ′ where a′, b′, c′, and d′ represent mol%,
The values are within the following ranges: 33≦a′+b′≦47 6≦c′≦28 36≦d′≦53