JP2015229724A - Broad band luminescent material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a luminescent material usable for a white light source exhibiting high color rendering property.SOLUTION: There is provided a broad band luminescent material containing ytterbium ion as a bivalent rare earth ion as a luminescent center in a fluorinated glass containing AlFof 20 to 45 mol%, alkali earth fluorinated product of 20 to 63 mol% and fluorine of at least one kind element selected from Y, La, Gd and Lu of 3 to 25 mol%, the fluorinated glass contains 1 to 15 mol% of a halogenated compound consisting of at least one kind selected from a group consisting of Al, Ba, Sr, Ca and Mg and at least one kind selected from a group consisting of Cl, Br and I and 0.1 to 20 mol% of at least one kind of oxide selected from a group consisting of Al, Ba, Sr, Ca, Mg and Y is contained.

Description

  The present invention relates to a broadband light emitting material capable of emitting light in a wide band.

  In recent years, incandescent bulbs, which are illumination light sources, are being replaced by white LEDs, and there is a demand for power-saving and high color rendering white LEDs. Currently, most of the white LEDs are composed of pseudo white that combines a YAG-Ce yellow phosphor and a blue GaN-based LED.

  In the combination of this conventional blue LED and YAG-Ce, since there are few components of cyan (-500 nm) and red (600 nm or more), the lack of wavelength components is compensated by adding a plurality of phosphors. For example, in Patent Document 1, a high color rendering white light source is realized by adding an Eu complex that emits red light to a YAG-Ce phosphor.

  On the other hand, when a high color rendering white light source is produced by mixing a plurality of phosphors in this manner, as pointed out in Patent Document 2, there is a problem that the color variation of individual white light emitters becomes large. there were. Even when a plurality of phosphors are mixed to form a white light emitter, the light emission intensity is remarkably low at the intermediate wavelength of the central light emission wavelength of each color phosphor, so that a white light emitter exhibiting high color rendering is realized. It was difficult. In addition, since the combination of the conventional blue LED and YAG-Ce described above has a small difference between the excitation wavelength (about 450 nm) and the fluorescence wavelength (center wavelength is about 550 nm, the wavelength shifts depending on the amount of Gd and Y added), the Stokes shift There is an advantage that the amount is small and luminous efficiency is good, but because the part of blue excitation light is used as illumination light, the color of the illumination light changes depending on the thickness of the phosphor layer through which the blue light passes (Patent Document 3). Therefore, it has been suggested that in the yellow phosphor portion mounted on the blue LED, the hue is different between the central portion and the peripheral portion of the element.

As a single material that emits white light, fluoride glass (Patent Document 4) containing divalent ytterbium ions (hereinafter Yb ²⁺ ), divalent europium ions (hereinafter Eu ²⁺ ) and P ( A fluorophosphate glass containing phosphorus is known (Patent Document 5, Non-Patent Document 1).

In Patent Document 4, the AlF ₃ 20 to 45 mol%, the MgF ₂ 0 to 15 mol% as the alkaline earth fluorides, the CaF ₂ 7 to 25 mol%, the SrF ₂ 0 to 15 mol%, and BaF ₂ In the range of 5 to 25 mol% and a total of 40 to 65 mol% of the alkaline earth fluoride, and further 10 to 25 fluorides of one or more elements selected from Y, La, Gd, and Lu are contained. There has been proposed a white light emitting material characterized in that a halide glass containing mol% contains Yb ²⁺ as an emission center.

Japanese Patent Application No. 2001-135116 JP 2007-335495 A JP 2008-88257 A JP 2008-201610 A Japanese Patent No. 3951585 Japanese Patent No. 3700502

Sawato adult, development of fluorescent glass, material integration Vol.17 No.3 (2004) M.Poulain et al., Chemtronics.Vol.3, no.2, pp.77-85.1988 J.W.M.Verwey et al., Journal of Physics and Chemistry of Solids, Volume 53, Issue 9, September 1992, Pages 1157-1162 Lihong Liu et al., “Photoliminescence properties of β-SiAlON: Si2 +, A novel green-emitting phosphre for white-emitting diodes”, Sci. Technol. Adv. Mater., 12, 034404 (2011) M. Poulain and C. Maze, “Chemistry of fluoride glasses,” Chemitronics 3, 77-85 (1988)

  As described above, in the combination of the current blue LED and YAG-Ce phosphor, cyan and red components are insufficient, and when a plurality of phosphors are added to compensate for the insufficient color component, each color is added. Since the emission intensity at the intermediate wavelength of the central emission wavelength of the phosphor is low, it has been difficult to realize a white light emitting material having high color rendering properties.

In order to obtain white light emission by Yb ²⁺ in fluoride glass, it can be obtained by melting the glass under conditions such as a reducing atmosphere (Non-patent Documents 2 and 3), but with a composition that is difficult to vitrify. For this reason, there has been a problem that it is necessary to prepare a glass by quenching the melt by pouring out into a metal mold, or the glass is colored gray. That is, when the rare earth element is reduced in the fluoride glass, the composition that can be selected is limited, and it is difficult to increase the white luminous efficiency of Yb ²⁺ ions in the fluoride glass.

In Patent Document 5, there is a description that a fluorophosphate glass containing Eu ²⁺ , terbium, samarium, manganese, or the like exhibits white fluorescence, but this includes blue emission by Eu ^2+, green emission by terbium, and samarium and manganese. By mixing red fluorescent light, a pseudo white color is obtained, and a continuous spectrum such as the sunlight spectrum cannot be obtained. Sometimes it looked a different color.

  Accordingly, an object of the present invention is to obtain a light emitting material that can be used for a white light source exhibiting high color rendering properties.

Halide glasses such as fluoride glass and chloride glass have been developed for many years as optical communication fibers because they have a wide-band transmission window that extends not only in the ultraviolet to visible region but also in the infrared region. Since the residual oxide contained in the fluoride glass raw material deteriorates the quality of the fluoride fiber, the residual oxide is fluorinated by mixing acidic ammonium fluoride (NH ₄ FHF) or the like (Non-patent Document 5). ). That is, in producing fluoride glass, it is common knowledge to remove oxides as much as possible.

However, as a result of intensive studies by the present inventors, it is possible to improve the emission intensity of Yb ²⁺ over a wide band by including a halide other than fluoride in a specific fluoride glass. It has been found that the excitation wavelength band can be shifted to a long wavelength without impairing the white light emission intensity by appropriately adding a cation of a specific oxide.

That is, the present invention provides AlF ₃ at 20 to 45 mol%, alkaline earth fluoride at 20 to 63 mol%, and fluoride of at least one element selected from the group consisting of Y, La, Gd and Lu. In a luminescent material containing ytterbium ion as a divalent rare earth ion serving as a luminescent center in a fluoride glass containing 25 mol%, the fluoride glass is selected from the group consisting of Al, Ba, Sr, Ca, and Mg. 1 to 15 mol% of a halide comprising at least one selected from the group consisting of Cl, Br, and I, and from the group consisting of Al, Ba, Sr, Ca, Mg, and Y A broadband light-emitting material containing 0.1 to 20 mol% of at least one selected oxide.

As the ytterbium ions as the divalent rare earth ions, Yb ²⁺ ions can be obtained by adding a Yb compound such as YbF ₃ or YbCl ₃ as a raw material and melting the glass in a reducing atmosphere. At this time, the Yb compound that has not been reduced to Yb ²⁺ remains in the glass composition.

  In addition, “broadband” in the present invention refers to a wavelength range of about 380 to 700 nm related to visible light.

  In addition, it was found that the light emitting material containing the ytterbium ion does not deactivate the fluoride glass of the present invention even when a raw material mixture in which oxygen is mixed in the raw material before vitrification is used.

That is, the present invention relates to a fluoride of at least one element selected from the group consisting of 20 to 45 mol% AlF ₃ , 20 to 63 mol% alkaline earth fluoride, Y, La, Gd and Lu. 25 mol%, halide 1-15 mol% consisting of at least one selected from the group consisting of Al, Ba, Sr, Ca and Mg and at least one selected from the group consisting of Cl, Br, and I, Mixing a raw material of fluoride glass containing 0 to 20 mol% of at least one oxide selected from the group consisting of Al, Ba, Sr, Ca, Mg, and Y, and a raw material containing ytterbium ions, A method for producing a broadband light-emitting material, comprising: a step of obtaining a raw material mixture; a step of melting the raw material mixture in a reducing atmosphere; and a step of cooling the melt after melting. A method for producing a broadband light-emitting material, wherein the step of obtaining a compound is performed under conditions containing oxygen.

  The raw material mixture contains oxygen, and the oxygen may be oxygen derived from the raw material or a mixture of oxygen contained in the atmosphere. As described above, it is generally required to remove oxide as much as possible in producing fluoride glass. In order to remove residual oxygen in the raw material mixture, oxygen and oxide are fluorinated. In addition to the raw material, a fluorinating agent such as acidic ammonium fluoride is added. In the production method of the present invention, the fluorinating agent is not added.

  According to the present invention, it is possible to obtain a light emitting material that can be used for a white light source exhibiting high color rendering properties. In addition, since the excitation wavelength band shifts to the longer wavelength side, the difference between the excitation wavelength and the fluorescence wavelength is reduced, so that improvement in light emission efficiency can be expected.

No. 1-No. Excitation spectrum for 3 samples monitored at a wavelength of 500 nm. No. 1-No. An emission spectrum of 3 samples excited at a wavelength of 375 nm.

The present invention provides ₃ to 25 fluorides of at least one element selected from the group consisting of 20 to 45 mol% AlF3, 20 to 63 mol% alkaline earth fluoride, Y, La, Gd and Lu. In a luminescent material containing ytterbium ion as a divalent rare earth ion serving as a luminescent center in a fluoride glass containing mol%, the fluoride glass is selected from the group consisting of Al, Ba, Sr, Ca, and Mg. Contains 1 to 15 mol% of a halide consisting of at least one selected from the group consisting of Cl, Br, and I, and selected from the group consisting of Al, Ba, Sr, Ca, Mg, and Y A broadband light-emitting material containing 0.1 to 20 mol% of at least one oxide.

AlF ₃ is a glass forming component constituting the fluoride glass of the present invention, and is contained in an amount of 20 to 45 mol% in the composition. AlF ₃ is less than 20 mole%, or greater than 45 mol% becomes difficult to vitrify. Moreover, it is good also as 30-40 mol% preferably.

Alkaline earth fluoride is a glass forming component constituting the fluoride glass of the present invention, similar to AlF ₃ described above, and is contained in an amount of 20 to 63 mol% in the composition. If the alkaline earth fluoride is less than 20 mol% or exceeds 63 mol%, the glass may be easily crystallized. Moreover, it is good also as 30-48 mol% preferably.

The content of alkaline earth fluorides described above, the MgF ₂ 0 to 15 mol%, the CaF ₂ 7 to 25 mol%, the SrF ₂ 0 to 22 mol%, and BaF ₂ 0-5 mol% Is preferable. The color tone at the time of light emission changes depending on the balance of each component of the alkaline earth fluoride as described above. Preferably MgF ₂ is 5 to 12 mol%, CaF ₂ is 10 to 20 mol%, SrF ₂ is 5 to 14 mol%, and BaF ₂ may be 0 to 5 mol%.

  Fluoride of at least one element selected from the group consisting of Y, La, Gd, and Lu is a glass forming component constituting the fluoride glass of the present invention, and contains 3 to 25 mol% in the composition. . Since the fluoride glass like the present invention has a composition that is potentially difficult to vitrify, an operation such as quenching the melt is performed, but when the fluoride is less than 3 mol% or more than 25 mol% In some cases, a suitable glass cannot be obtained in the process of operation described above. Moreover, it is good also as 10-20 mol% preferably.

1-15 mol% of halides comprising at least one selected from the group consisting of Al, Ba, Sr, Ca, and Mg and at least one selected from the group consisting of Cl, Br, and I are contained. If the content is less than 1 mol%, the emission intensity is not significantly increased, and if it exceeds 15 mol%, crystallization is likely to occur. Moreover, it is preferable to contain 1-12 mol% preferably. In particular, by using SrCl ₂ , CaCl ₂ , and MgCl ₂ that are not extremely low in melting point and can be melted even at a melting temperature of fluoride glass of 800 to 1200 ° C., it becomes difficult to crystallize, and fluorescence emission intensity Is preferable because of an increase.

  At least one oxide selected from the group consisting of Al, Ba, Sr, Ca, Mg, and Y is contained in a proportion of 0.1 to 20 mol%. When it exceeds 20 mol%, the white light emission intensity decreases and crystallization is likely to occur. Moreover, it is preferable to set it as 5 mol% or more because the effect of shifting the excitation wavelength to the long wavelength side becomes remarkable. Further, SrO and MgO can be preferably used because they are difficult to crystallize even if they are contained in a high concentration.

The present invention is a light-emitting material that emits fluorescence when excited with excitation light having a wavelength of 190 nm to 450 nm. When the excitation wavelength is less than 190 nm, not only cannot the light propagate in the air, but it also approaches the short wavelength side absorption edge of the fluoride glass as the base material, so that the base material is easily damaged. On the other hand, if it exceeds 450 nm, the absorption coefficient of Yb ²⁺ ions is extremely reduced, so that efficient excitation becomes difficult. In the present invention, the excitation wavelength band was shifted to the long wavelength side by containing an oxide. When the excitation wavelength band is shifted to the longer wavelength side, the difference between the excitation wavelength and the emission wavelength of the phosphor is reduced, so that the emission efficiency is expected to be improved. Further, excitation with a general-purpose excitation light source having a longer wavelength, for example, a 405 nm band light source used for recording in a Blu-ray device can be expected.

The ytterbium ion can be obtained by adding a Yb compound such as YbF ₃ or YbCl ₃ as a raw material and melting the glass in a reducing atmosphere. At this time, the preferred amount of the Yb compound added as a raw material may be appropriately selected. However, in the case of the present invention, for example, 0.01 to 1.0 mol% of the above-described Yb ²⁺ is added after the reduction. It can be a concentration. Moreover, in order to promote the reduction | restoration of a Yb compound, you may add metals, such as Al, 0.1 mol% or less.

  In addition, one preferred embodiment of the present invention is a broadband light-emitting material in which the above-described broadband light-emitting material is sealed using a sealing material in the same manner as a general phosphor (for example, Patent Document 6). That is, in the present invention, the broadband light emitting material is preferably dispersed in a sealing material.

  Although said sealing material is not specifically limited, Glass, a silicone resin, an epoxy resin, an organic inorganic hybrid composition, or mixtures thereof etc. are mentioned.

  Moreover, in the said embodiment, it is preferable to mix the broadband luminescent material used as fluorescent substance so that it may become 1-50 mass% in said sealing material. When the amount to be mixed is less than 1% by mass, the light emission is insufficient, and when it exceeds 50% by mass, the phosphor is settled, and a problem such as failure to obtain a uniform material tends to occur.

  In this embodiment, it is preferable to grind so that the median diameter D50 of the broadband luminescent material is 1 mm or less. On the other hand, if it exceeds 1 mm, the broadband luminescent material may easily settle. Moreover, since the lower limit of the median diameter D50 is about 1 μm, the normal phosphor powder may be 1 μm or more. A broadband light emitting material in which a phosphor using each broadband light emitting material is sealed can be excited by a gallium nitride light source having a wavelength of 190 nm or more and 450 nm or less.

  In this specification, the median diameter d50 is a value of the particle diameter at an integrated value of 50% of the particle size distribution measured by a laser diffraction / scattering method.

In the present invention, the fluoride of at least one element selected from the group consisting of 20 to 45 mol% AlF ₃ , 20 to 63 mol% alkaline earth fluoride, Y, La, Gd and Lu is 3 1 to 15 mol% of halide consisting of at least one selected from the group consisting of ˜25 mol%, Al, Ba, Sr, Ca and Mg and at least one selected from the group consisting of Cl, Br and I A raw material of fluoride glass containing 0 to 20 mol% of at least one oxide selected from the group consisting of Al, Ba, Sr, Ca, Mg, and Y, and a raw material containing ytterbium ions A process for obtaining a raw material mixture, a step of melting the raw material mixture in a reducing atmosphere, and a step of cooling the melt after melting, a method for producing a broadband light-emitting material, A method for producing a broadband luminescent material, wherein the step of obtaining a product is performed under a condition containing oxygen.

  As described above, by using the present invention, it is possible to obtain a broadband light emitting material without removing oxygen and oxide contained in the raw material mixture. For example, the atmosphere in the step of obtaining the raw material mixture is preferably performed in the atmosphere or in a gas containing oxygen at a concentration of the atmosphere.

  Further, as the reducing atmosphere, it is preferable to use a reducing gas or a mixed gas obtained by mixing a reducing gas with an inert gas. Examples of the reducing gas include gases such as hydrogen, carbon monoxide, and ammonia.

  Further, the temperature range at the time of melting is preferably 800 to 1300 ° C., and the holding time at the above temperature is preferably 10 to 240 minutes, for example, preferably maintained at 1100 ° C. for 60 minutes. Further, in order to treat the reducing atmosphere at a high temperature, a crucible may be disposed in a tubular furnace, and a method such as heater heating or induction heating by high frequency may be used. Especially when using a heater to heat a tubular furnace (for example, an electric furnace in which a quartz tube is placed in the core), use a tubular furnace with a heater because the quartz tube may deteriorate or deform at 1100 ° C or higher. In this case, the heating temperature is preferably 1100 ° C.

  The cooling step is preferably performed in a reducing atmosphere, but may be performed in an inert gas. As a method for cooling the melt, it may be cooled by leaving it on a metal plate as it is in a crucible, or it may be cooled rapidly by pulverizing the melt using a quenching roll or by atomizing it using gas atomization. May be.

  Examples of the present invention and comparative examples are described below.

Example 1
The compounds shown in Table 1 were used as starting materials. After adding the glass raw material prepared so as to be the mol% shown in 1 and 2 to the glassy carbon crucible, and adding 1 wt% of acidic ammonium fluoride externally to fluorinate the residual oxide contained in the raw material, After melting at 1000 ° C. for 1 hour in a reducing atmosphere (in nitrogen gas containing 3% by volume of hydrogen gas), the crucible and the copper block were cooled to obtain a sample. In addition, all the processes from preparation of raw materials, melting, and cooling were performed in a nitrogen atmosphere (both oxygen concentration and water content were 1 ppm or less).

Comparative Example 1
The compounds shown in Table 1 were used as starting materials. 4-No. A sample was obtained in the same manner as in Example 1 except that the glass raw material prepared so as to have the mol% shown in 9 was used. No. 3 is No.3. In contrast, the total amount of MgO was changed to MgF ₂ so that the content of Mg cations did not change. No. 4 and 5 are No. To 1, as does not change the content of Al cations, changing a part or whole amount of AlF ₃ in _Al 2 _{O 3.} No. 6 is No.6. In contrast, the total amount of CaF ₂ was changed to CaO so that the content of Ca cation did not change. No. 7 is No.7. To 1, as does not change the content of the Y cations, changing the total amount of YF ₃ to _Y 2 _{O 3.} No. 8 is a composition containing no halide other than fluoride and containing no oxide. No. 9 is a composition containing no halide other than fluoride.

<Measurement of XRD spectrum>
About the obtained sample, when the XRD spectrum was measured using the X-ray-diffraction apparatus (RIGAKU Ultima3), the halo pattern was obtained for samples 1-3, 8, and 9 and it was shown that it has not crystallized. The other samples 4 to 7 all showed crystallization and were not suitable for the purpose of the present invention.

<Measurement of emission spectrum and excitation spectrum>
About the obtained sample, the excitation spectrum and the emission spectrum were measured as follows using the fluorescence spectrophotometer (the JASCO make FP6500). Samples 8 and 9 were found to have low intensities in both the excitation spectrum and the emission spectrum and were not suitable as a light emitting material.

(Measurement of excitation spectrum)
No. 1-No. For the sample 3, the excitation spectrum was measured when the emission wavelength was 500 nm. The obtained excitation spectrum is shown in FIG. As can be seen from FIG. 1, as the amount of oxide introduced increases, the excitation spectrum shifts to the longer wavelength side and is distributed to a wavelength of 400 nm or more. That is, it has been found that by introducing an oxide, it may be possible to excite even a general-purpose excitation light source having a longer wavelength (for example, a 405 nm band light source used for recording in a Blu-ray device).

(Measurement of emission spectrum)
No. About 1-3 samples, it excited by wavelength 375nm and measured the emission spectrum. The obtained emission spectrum is shown in FIG. No. 1-No. In all three samples, a broad emission spectrum ranging from 400 to 700 nm was obtained. In other words, it was confirmed that broadband emission was maintained even when the oxide raw material was introduced.

<Measurement of quantum efficiency>
No. 1-No. The internal quantum efficiency and external quantum efficiency of the samples 3, 8, and 9 were measured and shown in Table 1. According to the description of Non-Patent Document 4, the measurement of the internal quantum efficiency and the external quantum efficiency is performed using a fluorescence spectrophotometer (FP-6500 manufactured by JASCO Corporation) to which an integrating sphere (ILF-533 manufactured by JASCO Corporation) is connected. The integrated intensity of the excitation light spectrum entering the integrating sphere is A, the integrated intensity of the excitation light spectrum absorbed by the sample is B, the integrated intensity of the fluorescence spectrum emitted from the sample is C, and the external quantum efficiency is C / A. The internal quantum efficiency was determined by C / B.

  The higher the value of the internal quantum efficiency and the external quantum efficiency, the higher the light emission efficiency. From Table 1, No. No. 3 compared with No. 3. It was found that 1 showed higher luminous efficiency. No. 2 is No.2. 1, no. Although the emission intensity was lower than 3, it was found that even a composition containing 20 mol% of the oxide component did not cause significant deactivation. Moreover, No. which is a composition which does not contain halides other than fluoride. 8 and 9 were low values for both internal quantum efficiency and external quantum efficiency.

  From the above, it was confirmed that a light emitting material having high luminous efficiency can be realized even when an appropriate amount of oxide is contained in the glass composition.

Example 2
The compounds shown in Table 1 were used as starting materials. The mixture was prepared in the air so that the mol% shown in 3 was obtained. Next, the mixed raw material mixture was moved under a nitrogen atmosphere (in nitrogen gas containing 3% by volume of hydrogen gas) and melted at 1000 ° C. for 1 hour without adding ammonium acid fluoride for removing residual oxide. The sample was obtained by cooling on a copper block with a crucible.

  Excitation and emission spectra are shown in FIGS. 1 and 2, respectively. As a result, a glass emitting light in a broad band is obtained, and the excitation spectrum is No. 1 which is a composition containing an oxide. It turned out that it shifts to the long wavelength side like 1 and 2. In addition, the emission spectrum shows a slight change in the peripheral structure of the Yb ion because the component on the long wavelength side is lower than that of the sample (No. 3) prepared by adding ammonium acid fluoride. I understood it. Further, when the quantum efficiency was measured by the above-described method, the internal quantum efficiency was 49% and the external quantum efficiency was 38%. A luminous efficiency higher than 3 was obtained. That is, it has been clarified that the quantum efficiency is not greatly impaired without removing residual oxygen.

Example 3
No. in Table 1 Using the sample No. 1, the sample was pulverized using a jet mill pulverizer (Nisshin Engineering, SJ-100) so that the median diameter D50 was about 50 μm, to obtain a powder of a luminescent material. Thereafter, the obtained powder was mixed with a silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., SCR-1011 (A / B)) at a ratio of 5% by mass, and then heated and cured at about 150 ° C. for 5 hours.

  When the obtained cured product was placed on an ultraviolet LED (manufactured by Nichia Corporation, NC4U134, center wavelength 385 nm), white light emission was obtained. From the above, it was confirmed that the broadband light-emitting material according to the present invention can be mounted on a light-emitting element by pulverizing and sealing in resin or glass.

Claims (4)

AlF ₃ 20 to 45 mol%, containing 20 to 63 mole% of alkaline earth fluoride, which Y, La, 3-25 mole% of a fluoride of at least one element selected from the group consisting of Gd and Lu In a luminescent material containing ytterbium ion as a divalent rare earth ion serving as a luminescent center in fluoride glass,
The fluoride glass comprises 1 to 15 halides comprising at least one selected from the group consisting of Al, Ba, Sr, Ca and Mg and at least one selected from the group consisting of Cl, Br and I. Containing mol%,
A broadband light-emitting material comprising 0.1 to 20 mol% of at least one oxide selected from the group consisting of Al, Ba, Sr, Ca, Mg, and Y. The alkaline earth fluoride, an MgF ₂ 0 to 15 mol%, the CaF ₂ 7 to 25 mol%, and characterized by containing SrF ₂ 0 to 22 mol%, and BaF ₂ 0-5 mol% The broadband light-emitting material according to claim 1. The broadband light-emitting material according to claim 1 or 2, wherein the broadband light-emitting material is dispersed in a sealing material. AlF ₃ 20 to 45 mol%, 20 to 63 mole% of alkaline earth fluorides, Y, La, a fluoride of at least one element selected from the group consisting of Gd and Lu 3 to 25 mol%, Al 1-15 mol% of a halide comprising at least one selected from the group consisting of Ba, Sr, Ca, and Mg and at least one selected from the group consisting of Cl, Br, and I, Al, Ba, Sr , A step of mixing a raw material of fluoride glass containing 0 to 20 mol% of at least one oxide selected from the group consisting of Ca, Mg, and Y and a raw material containing ytterbium ions to obtain a raw material mixture ,
Melting the raw material mixture in a reducing atmosphere;
A method for producing a broadband luminescent material, comprising: a step of cooling the melt after melting, wherein the step of obtaining the raw material mixture is performed under conditions containing oxygen.

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