JP5394903B2 - Phosphor, production method thereof, and light source - Google Patents

Description

  The present invention is a fluorescent lamp used for a display such as a cathode ray tube (CRT), a field emission display (FED), a plasma display (PDP), a lighting device such as a fluorescent lamp or a fluorescent display tube, a light emitting device for a liquid crystal backlight, etc. The present invention relates to a body, a manufacturing method thereof, and a light source using the phosphor.

  Currently, white LED lighting is attracting attention as the next generation lighting. Until now, discharge-type fluorescent lamps and incandescent lamps used as lighting devices have various problems such as containing harmful substances such as mercury, short life, and intense heat generation. However, in recent years, high-intensity LEDs that emit blue, near-ultraviolet, and ultraviolet light, which are necessary for white LED lighting, have been developed one after another, and white LED lighting can be used as the next-generation lighting. Research and development of whether it can be used or not is actively conducted.

  Two types of white LED lighting have been proposed, one is a multi-chip type that uses three primary color LEDs: a high-intensity red LED, a high-intensity blue LED, and a high-intensity green LED. This is a one-chip type system that combines a high-intensity ultraviolet LED, a high-intensity blue LED, etc., developed in the past, and a phosphor excited by ultraviolet to blue light generated from the LED.

  Comparing these two methods, the one-chip type is a combination of one LED and a phosphor compared to the multi-chip type, so it can be downsized, and the light guide for mixing colors is simple. In addition, it is not necessary to consider the driving voltage of each LED, the difference in light output, temperature characteristics, etc., and it is low cost. Furthermore, by using a phosphor with a broad emission spectrum, the emission spectrum of white light can be reduced. It has a feature that it can be close to the sunlight spectrum and is preferable as a light source for illumination because of its excellent color rendering properties. As a next-generation illumination, attention has been focused on the one-chip type method compared to the multi-chip type method. Yes.

  In general, two types of one-chip type white LED lighting in which the high-intensity LED and the phosphor are combined are considered. One is a combination of a high-intensity blue LED and a phosphor that emits yellow light when excited by the blue light generated from the LED, and uses the complementary color relationship between the blue light emission of the LED and the yellow light emission of the phosphor. The one that obtains white color and the other is LED that emits near ultraviolet and ultraviolet light, phosphor that emits red (R) light when excited by near ultraviolet and ultraviolet light generated from the LED, green (G) light emission In combination with a phosphor that emits blue (B) light, and a white color is obtained using a color mixture of light obtained from the R, G, B and other phosphors.

In the former case, that is, white LED lighting combining a high-intensity blue LED and a phosphor that emits yellow light when excited by the blue light generated from the LED, a high-intensity blue LED and a yellow phosphor (Y, Gd ) ₃ (Al, Ga) ₅ O ₁₂ : Ce (YAG: Ce). This white LED illumination utilizes the fact that the blue and yellow light colors are complementary, and has the feature that fewer phosphors are used than the method using near-ultraviolet / ultraviolet LEDs. In addition, the yellow phosphor YAG: Ce used has an excitation peak near the wavelength of 460 nm of the blue LED, so it can emit light with high efficiency, and high-intensity white LED illumination can be obtained. .

In the latter case, an LED that emits near ultraviolet / ultraviolet light, a phosphor that emits red (R) light when excited by near ultraviolet and ultraviolet light generated from the LED, a phosphor that emits green (G), and blue (B) Combined with a phosphor that emits light, white color is obtained by using the color mixture of light obtained from the R, G, B and other phosphors. In addition to white light, it is possible to obtain any emission color depending on the combination of R, G, and B, and the color mixture that uses R, G, and B instead of complementary colors. Due to the relationship, white light emission is obtained, so that the color rendering property is excellent. And as a phosphor used for the application, if it is a red phosphor, for example, Y ₂ O ₂ S: Eu, La ₂ O ₂ S: Eu, 3.5MgO · 0.5MgF ₂ · GeO ₂ : Mn, _{(La, Mn, Sm) 2} O 2 S · Ga 2 O 3: Eu may, if the green phosphor, for example, ZnS: Cu, Al, SrAl 2 O 4: Eu, BAM: Eu, Mn, Ba _If there is ₂ SiO ₄ : Eu and a blue phosphor, for example, BAM: Eu, Sr ₅ (PO ₄ ) ₃ Cl: Eu, ZnS: Ag, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) There is ₆ Cl: Eu.

  However, the former white LED lighting, which is a combination of a high-intensity blue LED and a yellow phosphor (YAG: Ce), has insufficient light emission on the long wavelength side in the visible light region. Thus, there is a problem that the red light emission spectrum in the vicinity of 600 nm to 650 nm is insufficient, white light emission slightly reddish like a light bulb cannot be obtained, and color rendering is poor. Furthermore, looking at the yellow phosphor YAG: Ce in terms of excitation range, it has the most efficient excitation band around 460 nm, but it does not have an efficient excitation band over a wide range. Due to variations in emission wavelength due to variations in light emitting elements during the manufacture of the LED, the emission wavelength of the blue LED deviates from the optimum excitation range of the YAG: Ce yellow phosphor. It may lead to a situation. When this happens, there is a problem that the color tone of white light obtained by combining blue light and yellow light changes.

  Also, in the latter white LED illumination, which is a combination of near-ultraviolet / ultraviolet LEDs and R, G, B and other phosphors, the red phosphor of the three color phosphors is closer to the excitation range than the other phosphors. Since the luminous efficiency is poor in the ultraviolet / ultraviolet region, the mixing ratio of only the red phosphor must be increased, and the green phosphor for improving the luminance is insufficient, so that a high luminance white color cannot be obtained. Furthermore, since the emission spectrum of the red phosphor is sharp, there is a problem that the color rendering is poor.

  To solve these problems, there is a broad peak in the range from yellow to red (580 nm to 680 nm), and a long wavelength from near UV / UV to visible light (250 nm to 550 nm), which is the excitation light. A phosphor with a good excitation band on the side is required. Recently, an oxynitride glass phosphor having a good excitation band on the long wavelength side and a broad emission peak from yellow to red (for example, see Patent Document 1), and a phosphor based on sialon (for example, Patent Documents 2 and 3), and phosphors containing nitrogen such as silicon nitride (for example, see Patent Documents 4 and 5) have been reported. In addition, the phosphor containing nitrogen has a characteristic of having a good excitation band even in light having a wavelength of 400 nm or more because it has a higher covalent bond ratio than an oxide-based phosphor. It attracts attention as a phosphor for LED lighting.

  In addition, the present inventors have a good excitation band for light in the wavelength range from near ultraviolet / ultraviolet to visible light (250 nm to 550 nm) and broaden the range from yellow to red (580 nm to 680 nm). A nitrogen-containing phosphor having a unique peak has been reported (Japanese Patent Application No. 2004-55536).

Japanese Patent Laid-Open No. 2001-214162 JP2003-336059 Japanese Patent Laid-Open No. 2003-124527 Special table 2003-515655 JP 2003-277746 A

  However, the phosphors reported by the present inventor have a broad peak in the range from yellow to red (580 nm to 680 nm), and the long range of excitation light from near ultraviolet / ultraviolet to visible light (250 nm to 550 nm). Although it is improved in that it has a good excitation band on the wavelength side, there is a problem that the emission intensity is not at a satisfactory level. Therefore, even when white LED lighting is manufactured in combination with near-ultraviolet / ultraviolet LEDs, blue LEDs, etc., the mixing ratio of only red phosphors still has to be increased, and there are not enough green phosphors to improve the brightness. In some cases, a high brightness white color cannot be obtained.

  Accordingly, the present inventors prepared various phosphor samples while pursuing the reason why sufficient emission intensity could not be obtained with the phosphor. As a result, the raw material used had a high melting point and the solid-phase reaction proceeded. Because of the difficulty, they came up with the idea that the reaction might be uneven.

The present invention has been made in consideration of the above-mentioned problems, and has a broad peak in the range from yellow to red (580 nm to 680 nm), and from near ultraviolet / ultraviolet to visible light (250 nm) that is excitation light. The object is to provide a phosphor having a good excitation band on the long wavelength side (˜550 nm) and an improved emission intensity.
Another object of the present invention is to have a broad peak in the range from yellow to red (580 nm to 680 nm), from the near ultraviolet / ultraviolet light that is the excitation light to the long wavelength side of visible light (250 nm to 550 nm). An object of the present invention is to provide a method for producing a phosphor that has a good excitation band and can improve the emission intensity.
Still another object of the present invention is to have a broad peak in the range from yellow to red (580 nm to 680 nm), and from the near ultraviolet / ultraviolet to the visible light (250 nm to 550 nm), which is the excitation light, on the long wavelength side. It is another object of the present invention to provide a light source using a phosphor having a good excitation band and an improved emission intensity.

The present inventors have further studied to promote the progress of the solid-phase reaction and realize a uniform reaction, and have come up with the idea that fluorine is contained in the phosphor.
That is, the first configuration for solving the above-described problem is a composition formula M _m A _a B _b N _n : Z (where M element is Ca having a valence of II, and A element is a valence of III Al, B element is Si having IV value, O is oxygen, N is nitrogen, Z element is Eu, m = a = b = 1, n = 2 / 3m + a + 4 / 3b )), and further containing 0.1 wt% or more and 3.0 wt% or less of fluorine.

A second configuration is the phosphor according to the first configuration, wherein the phosphor is in a powder form .

A third configuration is the phosphor according to the second configuration, wherein the phosphor has an average particle size of 20 μm or less and 0.1 μm or more.

A fourth configuration is a method for manufacturing the phosphor according to any one of the first to third configurations , and is a phosphor raw material represented by _a composition formula M _m A _a B _b O _o N _n : Z to a method for producing a phosphor comprising adding a full Tsu-containing compound.

The fifth configuration is a method of manufacturing the phosphor according to the fourth configuration ,
The phosphor manufacturing method is characterized in that the average particle diameter of AlN and Si ₃ N ₄ which are raw materials of the phosphor is 0.1 μm to 10.0 μm.

A sixth configuration is a method for manufacturing a phosphor according to the fourth or fifth configuration, wherein the fluorine compound is CaF ₂ and / or AlF _3. .

A seventh configuration is a light source including the phosphor according to any one of the first to third configurations and a light emitting unit.

An eighth configuration is the light source according to the seventh configuration , wherein the light emitted from the light emitting unit has a wavelength of 250 nm to 550 nm.

A ninth configuration is a light source according to the seventh or eighth configuration , wherein an LED (light emitting diode) is used as the light emitting unit.

According to the phosphors according to the first to sixth configurations, the composition formula M _m A _a B _b O _o N _n : Z (where M element is one or more elements having a valence of II, A element is one or more elements of Al, Ga, In, Tl, Y, Sc, P, As, Sb, and Bi that have a valence of III, and B element has a valence of IV One or more elements, O is oxygen, N is nitrogen, Z element is at least one element selected from rare earth elements or transition metal elements, and m> 0, a> 0 , B> 0, n = 2 / 3m + a + 4 / 3b-2 / 3o, o ≥ 0.) In particular, the values of m, a, and b are m = a = b = 1, o In the phosphor characterized in that the value of o is 0, the M element is Ca, the A element is Al, the B element is Si, and the Z element is Eu, the emission peak wavelength is 580 nm to 680 nm. In addition, it has excellent emission characteristics in the range, and furthermore, it is flat and efficient in a wide wavelength range from ultraviolet to visible light (wavelength 250 nm to 550 nm). It has the excitation band characteristics that have with the excitation band.

  In addition, since the phosphor contains boron and / or fluorine, the liquid phase generation temperature generated during firing is lowered, and the solid-phase reaction proceeds more uniformly. Can be improved.

  Furthermore, if the phosphor has a boron content of 0.001% to 3.0% by weight and the phosphor has a fluorine content of 0.1% to 3.0% by weight, the liquid phase formation temperature generated during firing The solid phase reaction proceeds more uniformly and the intense sintering can be suppressed, so that the luminous efficiency of the phosphor can be further improved.

  Since the phosphors according to the seventh and eighth configurations are in powder form, the phosphor can be easily applied or filled. Furthermore, since the average particle size of the phosphor powder is 20 μm or less and 0.1 μm or more, the luminous efficiency can be improved.

According to the method for manufacturing a phosphor according to the ninth to eleventh configurations, a boron compound such as BN or H ₃ BO ₃ is added as an additive in addition to the phosphor raw material, which occurs in the course of a solid-phase reaction. The production temperature of the liquid phase can be lowered, and a phosphor with improved luminous efficiency can be produced.

In addition to phosphor materials, fluorine compounds such as CaF ₂ and AlF ₃ can be added as additives to lower the liquid phase formation temperature generated during the solid-phase reaction, improving luminous efficiency. The phosphor can be manufactured.

According to the phosphor manufacturing method according to the twelfth configuration, AlN and Si ₃ N ₄ having an average particle diameter of 0.1 μm to 10.0 μm are used, which is suitable for coating and filling, and further for improving the emission intensity. A phosphor having a particle size can be produced.

  In the light sources according to the thirteenth to fifteenth configurations, the phosphor has an excitation band in light of a predetermined wide wavelength range (250 nm to 550 nm) emitted from the light emitting unit (LED in the fifteenth configuration). Since light is emitted, a combination of these phosphors and a light-emitting portion can provide a light source with high luminous efficiency that emits visible light or white light.

6 is a chart showing boron content, light emission characteristics, and the like in Ca _0.985 AlSiN ₃ : Eu _0.015, which is an example of the phosphor according to the present invention. 2 is a graph showing the relationship between the boron content and the relative emission intensity in the phosphor of FIG. 6 is a chart showing fluorine content, emission characteristics, and the like in Ca _0.985 AlSiN ₃ : Eu _0.015, which is an example of the phosphor according to the present invention. 4 is a graph showing the relationship between fluorine content and relative light emission intensity in the phosphor of FIG. 3.

Hereinafter, the best mode for carrying out the present invention will be described.
This embodiment has a broad peak in the range from yellow to red (580 nm to 680 nm), and is flat on the long wavelength side from the near ultraviolet / ultraviolet to visible light (250 nm to 550 nm). A phosphor having a highly efficient excitation band, and further a phosphor capable of obtaining excellent emission intensity by containing boron and / or fluorine in the phosphor and a method for producing the same.

  With a phosphor having a boron content of 0.001 wt% or more and 3.0 wt% or less, excellent light emission characteristics can be obtained. The boron content is more preferably 0.05% to 2.0% by weight, still more preferably 0.15% to 0.35% by weight. Although the detailed reason is unknown, many nitrides generally have a high melting point, and it is difficult for a liquid phase to occur when a solid-phase reaction is performed, and the reaction does not often proceed smoothly. However, in the case of containing boron, the liquid phase formation temperature is lowered and the liquid phase is easily generated, so that the reaction is promoted, and furthermore, the solid phase reaction proceeds more uniformly, so that the emission characteristics are excellent. It is considered that a phosphor can be obtained.

  If the boron content is 3.0% by weight or less, sintering does not become vigorous, and the light emission characteristics do not deteriorate in the crushing step, so that a desired effect can be obtained. Furthermore, if boron is contained in an amount of 3.0% by weight or less, it can be considered preferable because a base structure exhibiting excellent emission intensity can be maintained. Further, if the boron content is 0.001% by weight or more, it is considered that the liquid phase is sufficiently generated and a desired effect is obtained.

  Also, excellent emission intensity can be obtained even in a phosphor having a fluorine content of 0.1 wt% or more and 3.0 wt% or less. The fluorine content is more preferably 0.10 wt% to 2.0 wt%. Although the detailed reason is unknown, even for this reason, nitrides generally have a high melting point, and a liquid phase is difficult to occur when a solid-phase reaction occurs, and the reaction often does not proceed smoothly. In the case of containing fluorine, the liquid phase formation temperature is lowered as in the case of boron, the liquid phase is likely to be generated, the reaction is promoted, and the solid phase reaction proceeds more uniformly. It is considered that a phosphor having excellent emission characteristics can be obtained.

  If the fluorine content is 3.0% by weight or less, sintering does not become vigorous, and the light emission characteristics do not deteriorate in the crushing step, so that a desired effect can be obtained. Further, if the content of fluorine is 3.0% by weight or less, it is considered preferable because an impurity phase that does not contribute to light emission is not generated and the light emission characteristics are not deteriorated. Further, if the fluorine content is 0.1% by weight or more, it is considered that the liquid phase is sufficiently generated and the desired effect can be obtained.

  In the phosphor of the present embodiment, not only the case where boron and fluorine having the above contents are contained alone, but also the boron content is 0.001 wt% or more and 3.0 wt% or less, and the fluorine content is 0.1 wt%. As described above, it may be 3.0% by weight or less.

Further, the phosphor according to the present embodiment is a phosphor represented by the composition formula M _m A _a B _b O _o N _n : Z. Here, the M element is one or more elements having a valence of II, and the A element is Al, Ga, In, Tl, Y, Sc, P, As, Sb, Bi having a valence of III. Is one or more elements, B element is one or more elements having a valence of IV, O is oxygen, N is nitrogen, and Z element is a rare earth element or a transition metal element Is at least one element selected from

Furthermore, when the phosphor of the composition formula M _m A _a B _b O _o N _n : Z has a chemically stable composition, an impurity phase that does not contribute to light emission is less likely to occur in the phosphor, and thus the emission characteristics This is a preferable configuration that can suppress a decrease in the thickness. Therefore, in order to make the phosphor have a chemically stable composition, the phosphor has the following composition formula M _m A _a B _b O _o N _n : Z, m> 0, a> 0, b> Preferably, the composition satisfies 0, n = 2 / 3m + a + 4 / 3b-2 / 3o, and o ≧ 0.

Further, in the phosphor having the composition of the above-described composition formula M _m A _a B _b O _o N _n : Z, the M element is an element of + II valence, the A element is + III valence, the B element is an element of + IV valence, Since the element of -II valence and nitrogen is the element of -III valence, m, a, b, o, n have a composition such that n = 2 / 3m + a + 4 / 3b-2 / 3o If it exists, it will become zero, if the valence of each element is added together, and the composition of the said fluorescent substance becomes a more stable compound, and is preferable. In particular, when o = 0 and m: a: b: n = 1: 1: 1: 3, the phosphor is particularly excellent in emission characteristics and excitation band characteristics.

  However, in any case, a slight compositional deviation from the composition formula showing the composition of the phosphor is allowed. For example, a phosphor produced with o = 0, m: a: b: n = 1: 1: 1: 1: 3 basically does not contain oxygen, but the above-mentioned phosphor may contain oxygen. . This oxygen is the oxygen contained in the raw material from the beginning, the oxygen adhering to the surface, the oxygen mixed by oxidizing the surface of the raw material at the time of firing preparation or firing, and the oxygen adsorbed on the phosphor surface after firing It is thought that. As a result, 3% by weight or less of oxygen may be contained with respect to the mass of the phosphor.

  The M element is preferably at least one element selected from Be, Mg, Ca, Sr, Ba, Zn, Cd, Hg, and further selected from Mg, Ca, Sr, Ba, Zn Preferably, the element is at least one element, and most preferably Ca.

The element A is preferably at least one element selected from elements having a valence of III such as Al, Ga, In, Tl, Y, Sc, P, As, Sb, and Bi described above. Furthermore, it is preferably at least one element selected from Al and Ga, and most preferably Al. As Al, nitride AlN is used as a general heat transfer material or structural material, and it is easy to obtain and inexpensive, and in addition, the environmental load is also small and preferable.

The element B is preferably at least one element selected from elements having an IV valence such as C, Si, Ge, Sn, Ti, Hf, Mo, W, Cr, Pb, and Zr. Further, Si and / or Ge are preferable, and Si is most preferable. As Si, nitride Si ₃ N ₄ is used as a general heat transfer material or structural material, and it is easy to obtain and inexpensive, and in addition, the environmental load is small and preferable.

  The Z element is preferably at least one element selected from rare earth elements or transition metal elements. For example, in order to exhibit good color rendering properties in a lighting device or a light emitting device using the phosphor. The emission of the phosphor is preferably a spectrum with a wide half width. From this viewpoint, it is preferable that the Z element is at least one element selected from Eu, Mn, Sm, and Ce. Among these, when Eu is used as the Z element, the phosphor exhibits strong light emission from orange to red, and thus has high luminous efficiency and color rendering properties, and is more preferable as an activator for the phosphor used in lighting devices and light emitting devices.

  In addition, the fluorescent substance which has light emission of a different wavelength can be obtained with the kind of Z element which substituted a part of M element of the said fluorescent substance composition.

Further, when the phosphor is expressed as M _m A _a B _b O _o N _n : Z _z , the addition amount of the Z element is the molar ratio z / (m + z) between the M element and the activator Z element. Is preferably in the range of 0.0001 or more and 0.5 or less. When the molar ratio z / (m + z) between the M element and the activator Z element is in the range, it is possible to avoid a decrease in light emission efficiency due to concentration quenching due to excessive activator content, It is also possible to avoid a decrease in light emission efficiency due to a lack of light emission contributing atoms due to an insufficient activator content. In addition, the value of z / (m + z) is more preferably in the range of 0.005 or more and 0.1 or less. However, the optimum value in the range of z / (m + z) varies slightly depending on the type of activator element Z and the type of M element. Furthermore, by controlling the addition amount of the activator element Z, the peak wavelength of the emission wavelength of the phosphor can be set by shifting, which is useful when adjusting the luminance.

On the other hand, in the phosphor having the composition of the above-described composition formula M _m A _a B _b O _o N _n : Z, the crystal structure of the phosphor is changed by controlling the molar ratio o of oxygen, The peak wavelength of the emission wavelength can be shifted in the range of 600 nm to 660 nm. However, when m = a = b = 1, the molar ratio o of oxygen is preferably controlled in the range of 0 ≦ o ≦ m, more preferably in the range of 0 ≦ o ≦ 0.3.

  When the phosphor in the present embodiment is used in the form of powder, the average particle size of the phosphor powder is preferably 20 μm or less. This is because light emission is considered to occur mainly on the particle surface in the phosphor powder, and if the average particle size is 20 μm or less, a surface area per unit weight of the powder can be secured and a reduction in luminance can be avoided. . Furthermore, the density of the powder can be increased even when the powder is formed into a paste and applied to a light-emitting element or the like, and a decrease in luminance can be avoided also from this viewpoint. Further, according to the study by the present inventors, although the detailed reason is unknown, it has been found that the average particle size is preferably larger than 0.1 μm from the viewpoint of the luminous efficiency of the phosphor powder. From the above, the average particle diameter of the phosphor powder in the present embodiment is preferably 0.1 μm or more and 20 μm or less.

In the production of the phosphor in the present embodiment, any of the nitrides, oxides, and compounds may be used as raw materials for the M element (+ II valence), A element (+ III valence), and B element (+ IV valence). good. For example, M element nitride (M ₃ N ₂ ), oxide (MO), A element, and B element nitride (AN, B ₃ N ₄ ) may be used for mixing. By controlling the compounding ratio of the nitride, oxide, and both, the amount of oxygen and nitrogen in the phosphor can be controlled without changing the value of m. Of course, nitrides and oxides are not limited to compounds combined only with oxygen and compounds combined only with nitrogen, but are decomposed during firing, such as carbonates and oxalates. In the case of a nitride, it is a compound having the element and nitrogen.

  However, in the following description, for convenience, the compound having the element and oxygen will be described as an example of the oxide of the element, and the nitride of the element as the compound having the element and nitrogen.

For example, when weighing under the conditions of oxygen molar ratio o = 0, m = a = b = 1, each raw material is molar ratio M ₃ N ₂ : AN: B ₃ N ₄ = 1: 3: 1 And weigh it. Further, at this time, if the element Z, for example, II-valent element of the activator, the element Z substitute a part of the element M, the phosphor in consideration of this replacement M _m A _a B _b When expressed as O _o N _n : Z _z , it is preferable that (m + z) = a = b = 1. Thereby, the composition of the phosphor can be a chemically stable composition. If the oxygen molar ratio o = 0.25 and m = a = b = 1 are weighed, each raw material is molar ratio M ₃ N ₂ : MO: AN: B ₃ N ₄ = 0.75: 0.75: Weighing with 3: 1.

Furthermore, in this Embodiment, it discovered that the light emission characteristic improved by adding a boron compound and a fluorine compound as an additive. In this case, it is preferable to add a boron compound such as BN, H ₃ BO ₃ , B ₂ O ₆ , B ₂ O ₃ , BCl ₃ or the like so that boron is 3.0% by weight or less in the sample after firing. BN and H ₃ BO ₃ are preferred. Mixture use of these boron compounds is also possible. Since a boron compound is a substance having a high thermal conductivity, it is presumed that by adding it to the raw material, the temperature distribution of the raw material becomes uniform during firing and the light emission characteristics are improved in order to promote the solid-phase reaction. As an addition method, it is possible to add and mix together at the time of mixing raw materials.

In the case of a fluorine compound, it is preferable to add a fluorine compound such as CaF ₂ , AlF ₃ , EuF ₂ , or EuF ₃ so that fluorine is 3.0 wt% or less in the sample after firing. These fluorine compounds have a lower melting point than the raw materials AlN and Si ₃ N ₄ , tend to form a liquid phase, and promote the diffusion of atoms by covering the surface of the raw material particles such as AlN and Si ₃ N _4. Therefore, it is considered that the emission characteristics are improved. Fluorine compounds in which fluorine and calcium, fluorine and aluminum, and fluorine and europium are bonded to each other are added to phosphors with M element as Ca, A element as Al, B element as Si, and Z element as Eu. It is considered preferable because it contains the same element as the element of the composition formula. Mixture use of these fluorine compounds is also possible.

  The amount of boron and fluorine added to these raw materials does not necessarily match the content of boron and fluorine after firing. This is because boron and fluorine are partially scattered during firing, so the content is less than when adding raw materials, and each raw material also contains a small amount of boron and fluorine. For this reason, it becomes more than that at the time of addition of the raw material. For the sake of convenience, the following description will be made without the description of oxygen in the composition formula.

Next, a method for manufacturing the phosphor in the present embodiment will be described by taking Ca _0.985 AlSiN ₃ : Eu _0.0150 as an example.
Each nitride raw material of M element, A element, and B element may be a commercially available raw material, but preferably has a purity of 2N or higher, and more preferably 3N or higher. In addition, as for this raw material, a material having an approximate particle size and shape may be prepared in accordance with the particle size and shape required for the finally obtained phosphor. The average particle size required for the phosphor is 0.1 μm to 20.0 μm, more preferably 1.0 μm to 10.0 μm. From the viewpoint of controlling the particle size of the phosphor particles after firing, the average particle size of each raw material is 0.1 μm. To 10.0 μm are preferred. The average particle size of all raw materials is preferably 0.1 μm to 10.0 μm, but at least AlN and Si ₃ N ₄ which are raw materials of elements forming the parent structure and have a high melting point have the above average particle size. By using the phosphor, the phosphor having excellent light emission characteristics can be produced. If the raw material has an average particle size of 0.1 μm or more, it is difficult to sinter, and the emission intensity does not decrease in the crushing step after firing. Further, if the average particle size is 20.0 μm or less, the reaction becomes uniform, which is preferable. Similarly, the following Z element raw materials and additive raw materials preferably have an average particle diameter of 0.1 μm to 20.0 μm, more preferably 1.0 μm to 10.0 μm.

  The raw material for the element Z may be a commercially available nitride raw material or oxide raw material, but it is also preferable that the purity is higher, preferably 2N or higher, more preferably 3N or higher. In addition, since oxygen contained in the oxide raw material of the Z element is also supplied during the composition of the phosphor, the oxygen supply amount in the above-described mixing study of the M element raw material, the A element raw material, and the B element raw material Is preferably taken into account. In the case where it is not desired to include oxygen in the composition of the phosphor, a Z element simple substance or a nitride of Z element may be used as a raw material.

  The raw material of the additive may be a commercially available boron compound or a fluorine compound raw material, but it is also preferable that the purity is higher, preferably 2N or higher, more preferably 3N or higher.

For production of Ca _0.985 AlSiN ₃ : Eu _0.0150 , for example, prepare Ca ₃ N ₂ (2N), AlN (3N), and Si ₃ N ₄ (3N) as nitrides of M element, A element, and B element, respectively. do it. Eu ₂ O ₃ (3N) is prepared as a Z element, and a boron compound and / or a fluorine compound is prepared as an additive.

About these raw materials, the mixing ratio of each raw material was set to 0.985 / 3 mol of Ca ₃ N ₂ so that the molar ratio of each element was Ca: Al: Si: Eu = 0.985: 1: 1: 1.015, Weigh 1 mol of AlN, 1/3 mol of Si ₃ N ₄ and 0.015 / 2 mol of Eu ₂ O ₃ , and weigh any amount of additives and mix them together.

  The weighing / mixing is conveniently performed in a glove box under an inert atmosphere in order to prevent oxidation of nitride as a raw material. Moreover, since the nitride of each raw material element is easily affected by moisture, it is preferable to use an inert gas from which moisture has been sufficiently removed. When a nitride raw material is used as each raw material element, dry mixing is preferable as a mixing method in order to avoid decomposition of the raw material, and a normal dry mixing method using a ball mill, a mortar, or the like may be used. In addition, if an organic solvent which can suppress decomposition | disassembly of a raw material is used, wet mixing is also possible.

The mixed raw material is put into a crucible, and is in an inert atmosphere such as nitrogen, or in an ammonia atmosphere, a hydrogen atmosphere, and a mixed gas atmosphere of nitrogen and hydrogen at 1000 ° C. or higher, preferably 1300 ° C. or higher, more preferably 1400 to Hold at 1600 ° C. for 30 minutes or longer, preferably 3 hours or longer, and fire in a pressurized state in the furnace. The pressure in the furnace may be a pressurized state, and a phosphor having sufficiently satisfactory characteristics can be obtained even at 3.0 kgf / cm ² or less. The holding time can be shortened because the reaction proceeds more rapidly as the sintering temperature is higher. On the other hand, even when the sintering temperature is low, the desired light emission characteristics can be obtained by maintaining the temperature for a long time. However, as the sintering time is longer, particle growth proceeds and the particle shape becomes larger, so the sintering time may be set according to the target particle size.

In addition, as a crucible, there can be used an Al ₂ O ₃ crucible, a Si ₃ N ₄ crucible, an AlN crucible, a sialon crucible, a C (carbon) crucible, a BN (boron nitride) crucible, or the like that does not cause any problems. However, it is preferable to use a BN crucible because it can avoid contamination of impurities from the crucible. In addition, when using a BN crucible, the emission characteristics of the phosphor can be improved because B is mixed from the portion where the BN crucible and the raw material are in contact without adding BN powder. It is a part in contact with the crucible, and the improvement is small compared with the case where B is mixed into the whole by mixing the raw material powder and BN powder. In other words, B may be mixed by using a BN crucible, but it is more preferable to mix BN powder and raw material powder and mix B in the whole.

After the firing is completed, the fired product is taken out from the crucible, and ground using a grinding means such as a mortar and a ball mill, and then ground to a predetermined average particle size, and the phosphor represented by the composition formula Ca _0.985 AlSiN ₃ : Eu _0.0150 Can be manufactured.

  When other elements are used as M element, A element, B element, and Z element, and when the activation amount of Eu as an activator is changed, the blending amount at the time of charging each raw material is a predetermined composition. By adjusting the ratio, a phosphor having a predetermined composition formula can be manufactured by the same manufacturing method as described above.

  As described above, the phosphor in the present embodiment has a good excitation band in a wide range of ultraviolet to visible light (wavelength range 250 nm to 550 nm), and the emission intensity of the phosphor is high. In combination with the above-described light emitting section (such as an LED light emitting element and a discharge lamp described later) that emits ultraviolet to visible light, a high output light source and an illumination unit including this light source can be obtained.

That is, by combining the phosphor of the present embodiment in powder form with a light emitting part (particularly, a light emitting part that emits light in a wavelength range of 250 nm to 550 nm) by a known method, Various display devices and lighting units can be manufactured. For example, it is possible to manufacture fluorescent lamps, lighting units, and display devices by combining with a discharge lamp that generates ultraviolet light as a light emitting part, and also by combining with an LED light emitting element that emits visible light from ultraviolet as a light emitting part. Lighting units and display devices can be manufactured.
The manufactured lighting unit has a broad peak in the range from yellow to red (580 nm to 680 nm), and from the near ultraviolet / ultraviolet light, which is the excitation light, to the long wavelength side, visible light (250 nm to 550 nm). It had a good excitation band and high emission intensity.

(Comparative Example 1)
As Comparative Example 1, commercially available Ca ₃ N ₂ (2N), AlN (3N, average particle size 1.76 μm), Si ₃ N ₄ (3N, average particle size 0.774 μm), Eu ₂ O ₃ (3N) were prepared. After weighing each raw material so that Ca ₃ N ₂ is 0.985 / 3 mol, AlN is 1 mol, Si ₃ N ₄ is 1/3 mol, and Eu ₂ O ₃ is 0.015 / 2 mol, respectively, under a nitrogen atmosphere In a glove box, mixing was performed using a mortar. Put the mixed raw material into a Si ₃ N ₄ crucible, hold and fire in an oven pressure of 0.5 kgf / cm ² at 1500 ° C in a nitrogen atmosphere for 3 hours, then cool from 1500 ° C to 200 ° C in 1 hour, and firing is completed Then, crushing was performed to obtain a phosphor represented by the composition formula Ca _0.985 AlSiN ₃ : Eu _0.015 . In addition, this composition formula is a composition estimated from the used raw material and a mixture ratio.

The phosphor obtained was irradiated with a monochromatic excitation light source having a wavelength of 460 nm, and the emission characteristics were measured. In the measured emission characteristic item, the peak wavelength is the wavelength of the peak showing the wavelength with the highest emission intensity in the emission spectrum in nm units. The emission intensity is the intensity at the peak wavelength expressed as a relative intensity. The intensity of Comparative Example 1 is normalized to 100%. The chromaticity is obtained by calculating the chromaticity x, y by a calculation method defined in JISZ8701. Further, the boron concentration contained in the phosphor particle sample is a value measured by absorptiometry.
FIG. 1 shows the measurement results of the composition formula, boron concentration analysis results, emission characteristics (peak wavelength, emission intensity, chromaticity), and powder characteristics (particle diameter, specific surface area BET) of the phosphor.

(Examples 1-4)
In Examples 1 to 4, in the production of the phosphor sample, the Ca ₃ N ₂ (2N), AlN (3N), Si ₃ N ₄ (3N), and Eu ₂ O ₃ (3N) described in Comparative Example 1 were used. In addition to each raw material, boron nitride BN (3N) was added as an additive, and the crucible was changed from a Si ₃ N ₄ crucible to a BN crucible, and each was changed to Examples 1 to 4, and each was similar to Comparative Example 1. A phosphor sample was prepared.

That is, in Example 1, 0.1% by weight of BN powder was added to a mixed raw material of Ca _0.985 AlSiN ₃ : Eu _0.015 (before firing), and similarly, 0.5% by weight in Example 2, 1.0% by weight in Example 3, In Example 4, 2.0 wt% BN powder was added.

  In Examples 1 to 4, as in Comparative Example 1, the composition formula of the phosphor, the boron concentration analysis result, the emission characteristics (peak wavelength, emission intensity, chromaticity), and powder characteristics (particle diameter, specific surface area BET) ) Measurement results are shown in FIG. 1, and FIG. 2 shows the relationship between the boron content and the relative luminescence intensity (relative intensity of the luminescence intensity of Comparative Example 1 is 100%).

  From FIG. 1, it can confirm that boron content increases by adding BN powder. The boron content of Comparative Example 1 is 0.0001% by weight or less. However, when each of the BN powders of Examples 1 to 4 is added, the boron content increases, and boron is added when the BN powder addition amount is 0.1% by weight. The content is 0.063% by weight. When the added amount of BN powder is 0.5% by weight, the boron content is 0.170% by weight. When the added amount of BN powder is 1.0% by weight, the boron content is 0.310% by weight and the added amount of BN powder is 2.0% by weight. Then the boron content increased to 0.640% by weight.

  Further, it can be confirmed from FIG. 1 and FIG. 2 that the emission intensity is improved by containing boron. The emission intensity showed a peak when the boron content was in the range of 0.15 wt% to 0.35 wt%, and the emission intensity was improved by 19.6% compared to Comparative Example 1 without addition of BN. Further, when boron is contained, the peak wavelength tends to shift to the longer wavelength side. Furthermore, when the boron content is 0.310% by weight or less (Examples 1 to 3), the average particle diameter is almost the same as that of Comparative Example 1 without BN addition, but when the boron content is 0.640% by weight (Example 4). The average particle size was 10.58 μm, which was about twice that of Comparative Example 1 (5.851 μm) without BN addition. From this result, it is considered that a phosphor containing boron in a certain range promotes the reaction and improves the emission intensity.

(Examples 5 to 7)
In Examples 5 to 7, in the production of the phosphor sample, the Ca ₃ N ₂ (2N), AlN (3N), Si ₃ N ₄ (3N), and Eu ₂ O ₃ (3N) described in Comparative Example 1 were used. In addition to the raw materials, calcium fluoride CaF ₂ (3N) was added as an additive, and the crucible was changed from a Si ₃ N ₄ crucible to a BN crucible. A phosphor sample was prepared in the same manner as described above.

That is, in Example 5, 0.025 mol of CaF ₂ was added to a raw material capable of 1.0 mol of Ca _0.985 AlSiN ₃ : Eu0.015. Similarly, in Example 6, 0.050 mol of CaF ₂ was added. 0.100 mol of CaF ₂ was added.

  For Comparative Example 1 and Examples 5 to 7, measurement of composition formulas, fluorine concentration analysis results, emission characteristics (peak wavelength, emission intensity, chromaticity), powder characteristics (particle diameter, specific surface area BET) of each phosphor The results are shown in FIG. 3, and FIG. 4 shows the relationship between the fluorine content and the relative light emission intensity (relative intensity of the light emission intensity of Comparative Example 1 is 100%).

From Figure 3, it can be confirmed that the fluorine content is increased by the addition of CaF ₂ powder. Although the fluorine content of Comparative Example 1 is 0.10% by weight or less, when CaF ₂ powder is added in each of Examples 5 to 7, the fluorine content increases. When the CaF ₂ powder addition amount is 0.025 mol, the fluorine content When the CaF ₂ powder addition amount was 0.050 mol, the fluorine content increased to 0.80 wt%, and when the CaF ₂ powder addition amount was 0.100 mol, the fluorine content increased to 1.70 wt%.

Further, as in the case of boron, it can be confirmed from FIG. 3 and FIG. 4 that the emission intensity is improved by containing fluorine. The emission intensity gradually increases until the fluorine content is 0.40% by weight, and decreases when the fluorine content exceeds 0.40% by weight. Further, the emission intensity showed a peak at a fluorine content of 0.40% by weight, and was improved by 17.3% compared to Comparative Example 1 in which no CaF _{2 was} added. Further, when fluorine is contained, the peak wavelength tends to slightly shift to the longer wavelength side. Furthermore, when the fluorine content was 1.70% by weight or less, the average particle size was almost the same as in Comparative Example 1 without BN addition. From this result, it is considered that the reaction is promoted and the emission intensity is improved in the phosphor containing fluorine in a certain range as well as boron.

Claims (9)

Composition formula M _m A _a B _b N _n : Z (where M element is Ca having a valence of II, A element is Al having a valence of III, and B element is Si having a valence of IV) , N is nitrogen, Z element is Eu, m = a = b = 1, n = 2 / 3m + a + 4 / 3b ), and further fluorine is 0.1 wt% or more, 3.0 A phosphor containing no more than wt%.   The phosphor according to claim 1, wherein the phosphor is in a powder form.   The phosphor according to claim 2, wherein the phosphor has an average particle size of 20 μm or less and 0.1 μm or more. A method for producing the phosphor according to any one of claims 1 to 3,
A method for producing a phosphor, comprising adding a fluorine compound to a phosphor raw material represented by _a composition formula M _m A _a B _b N _n : Z. It is a manufacturing method of the fluorescent substance according to claim 4,
A method for producing a phosphor, characterized in that an average particle size of AlN and Si ₃ N ₄ which are raw materials of the phosphor is 0.1 μm to 10.0 μm. 6. The method for producing a phosphor according to claim 4, wherein the fluorine compound is CaF ₂ and / or AlF ₃ .   A light source comprising the phosphor according to claim 1 and a light emitting unit.   The light source according to claim 7, wherein the light emitted from the light emitting unit has a wavelength of 250 nm to 550 nm.   9. The light source according to claim 7, wherein an LED (light emitting diode) is used as the light emitting unit.

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