JP2009238886A - Wavelength converter and light-emitting device, and lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wavelength converter and a light-emitting device, and a lighting device capable of improving luminous efficiency. <P>SOLUTION: The wavelength converter 19 converts the wavelength of light emitted from a light source and outputs output light including the wavelength-converted light. In the wavelength converter, phosphors for emitting red light, emitting blue light, and emitting green light are dispersed in a transparent matrix, the quantization efficiency of the phosphor for emitting blue light is higher than that of the phosphor for emitting red light and the phosphor for emitting green light, and the average grain size of the phosphor for emitting blue light is smaller than that of the phosphor for emitting red light and the phosphor for emitting green light. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is equipped with a wavelength converter that converts the wavelength of light emitted from a light source such as an LED (Light Emitting Diode) and outputs output light including the light whose wavelength has been converted, or a wavelength converter. The present invention relates to a light emitting device and a lighting device including the light emitting device.

  A light-emitting element made of a semiconductor material (hereinafter also referred to as “LED chip”) is small in size, has high power efficiency, and vividly develops color. LED chips have excellent features such as long product life, strong resistance to repeated on / off lighting, and low power consumption, so they are expected to be applied to backlight sources such as liquid crystals and lighting sources such as fluorescent lamps. Has been.

  The LED chip converts a part of the light of the LED chip with a phosphor, and mixes and emits the wavelength-converted light and the light of the LED that is not wavelength-converted, thereby producing a color different from that of the LED light. It is applied to light emitting devices that emit light.

As such a light emitting device, for example, a phosphor emitting yellow light such as a YAG phosphor represented by a composition formula of (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ is arranged on a blue LED chip. Is known.

  In this light emitting device, when the light emitted from the LED chip is irradiated onto the yellow component phosphor, the phosphor emitting yellow light is excited to emit visible light, and this visible light is used as an output. However, when the brightness of the LED chip is changed, the light quantity ratio between blue and yellow changes, so that there is a problem that the color tone of white changes and the color rendering property is inferior.

  Therefore, in order to solve such problems, a purple LED chip having a peak of 400 nm or less is used as the LED chip, and the wavelength converter employs a structure in which three kinds of phosphors are mixed in a polymer resin. However, it has been proposed to emit white light by converting violet light into red, green, and blue wavelengths (see Patent Document 1). Thereby, a color rendering property can be improved.

  However, the light emitting device described in Patent Document 1 has a problem in that the luminous efficiency of white light cannot be improved because the quantum efficiency of the phosphor that emits red light in the ultraviolet region near 400 nm of excitation light is low.

In view of such circumstances, phosphors that emit red light have been developed, and conventionally, silicates that emit red light represented by the chemical formula Ba _3-xy Eu _x Mn _y MgSi ₂ O ₈ have been developed. System phosphors are known (for example, Non-Patent Document 1).

  In addition, a phosphor containing Eu has been developed as a phosphor emitting in yellow to green (hereinafter referred to as yellow-green) that can be used in combination with an LED chip having a peak wavelength of 400 nm or less as a light emitting element ( Patent Document 2).

This Patent Document 2 discloses a phosphor represented by Sr2 _-xy Ba _x Eu _y SiO ₄ , wherein the molar ratio of Sr to the molar ratio of Si, the molar ratio of Ba, and the molar ratio of Eu. A phosphor having a total ratio (Sr + Ba + Eu) / Si of 2 is disclosed.
JP 2002-314142 A JP 2004-115633 A Journal of Electrochemical Society, 1968, P773-778

However, as a phosphor emitting red light of the wavelength converter described in Patent Document 1, an alkali represented by the chemical formula of Ba _3-xy Eu _x Mn _y MgSi ₂ O ₈ described in Non-Patent Document 1 is used. An alkaline earth metal silicate represented by a chemical formula of Sr _2-xy Ba _x Eu _y SiO ₄ described in Patent Document 2 as an earth metal silicate phosphor and a phosphor emitting green light Even when each of the phosphors is used, there is still a problem that the red phosphor and the green phosphor have low quantum efficiency and the light emitting device has low luminous efficiency.

  An object of this invention is to provide the wavelength converter and light-emitting device which can improve luminous efficiency, and an illuminating device.

  The wavelength converter of the present invention is a wavelength converter that converts the wavelength of light emitted from a light source and outputs output light including the light whose wavelength has been converted, and emits red light in a transparent matrix. Body, phosphors emitting blue light, and phosphors emitting green light, and the quantum efficiency of the phosphors emitting blue light is that of the phosphors emitting red light and the phosphors emitting green light. The average particle diameter of the phosphor that emits blue light is smaller than the average particle diameter of the phosphor that emits red light and the phosphor that emits green light.

  In the wavelength converter of the present invention, the phosphor having a high quantum efficiency that emits blue light (hereinafter sometimes referred to as a blue light-emitting phosphor) has a smaller average particle size than other phosphor particles, and thus emits blue light. Phosphor that emits red light (hereinafter sometimes referred to as a red light emitting phosphor) and blue light that is reflected or wavelength-converted by the light hitting the phosphor and emits green light (hereinafter, green light emitting fluorescence) In other words, the quantum efficiency of the red light emitting phosphor and the green light emitting phosphor can be improved.

  In the wavelength converter of the present invention, an average particle diameter of the phosphor emitting blue light is 10 μm or less, and an average particle diameter of the phosphor emitting red light and the phosphor emitting green light is 15 μm or more. It is characterized by being. In such a wavelength converter, the light reflected by the blue light-emitting phosphor or the wavelength-converted blue light is increased, and the red light-emitting phosphor and the green light-emitting phosphor are easily hit. The quantum efficiency of the green light emitting phosphor can be increased.

  The light-emitting device of the present invention comprises a light-emitting element, a base on which the light-emitting element is mounted, and the wavelength converter that converts the wavelength of light emitted from the light-emitting element. To do. In such a light emitting device, the luminous efficiency of white light can be improved.

  Furthermore, an illumination device according to the present invention includes a plurality of the light emitting devices described above. Since such a lighting device includes a plurality of the light emitting devices, color rendering can be improved.

  In the wavelength converter of the present invention, since the average particle size of the blue light emitting phosphor is smaller than other phosphors, the light hitting the phosphor emitting blue light is reflected, or the blue light whose wavelength is converted, The red light emitting phosphor and the green light emitting phosphor hit the red light emitting phosphor and the green light emitting phosphor, so that the quantum efficiency of the red light emitting phosphor and the green light emitting phosphor can be improved.

  Since the light emitting device and the lighting device of the present invention can improve the quantum efficiency of the red light emitting phosphor and the green light emitting phosphor, the color rendering properties can be improved.

  A wavelength converter of the present invention and a light emitting device equipped with the wavelength converter will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an embodiment of a light emitting device 11 of the present invention. According to FIG. 1, the light emitting device 11 of the present invention covers a substrate (base body) 15 on which an electrode 13 is formed, a light emitting element 17 provided on the substrate 15, and a light emitting element 17 on the substrate 15. 1 layer of wavelength converters 19 and a reflecting member 21 that reflects light. Reference numeral 22 is a wire, and reference numeral 16 is an adhesive.

  The wavelength converter 19 includes, for example, a phosphor (not shown) that emits fluorescence (blue) having a wavelength of 430 nm to 490 nm and a phosphor (green) that emits fluorescence (green) having a wavelength of 520 nm to 570 nm in a transparent matrix. 1), a phosphor (not shown) that emits fluorescence (red) having a wavelength of 600 nm to 650 nm is contained, and a part of the wavelength of light emitted from the light emitting element 17 as a light source is converted into another wavelength. Thus, the output light including the light whose wavelength has been converted is output, and the light of the light emitting element 17 having a certain wavelength is converted into light having another wavelength.

  The phosphor that emits blue light is made of, for example, a material having high quantum efficiency that is excited by light having a wavelength of around 400 nm. On the other hand, the phosphor emitting green is made of a material excited by light having a wavelength of 400 nm to 460 nm, for example. The phosphor emitting red light is made of a material that is excited not only by a wavelength of 400 nm to 460 nm but also by light in the vicinity of 550 nm.

  Further, in the wavelength converter of the present invention, it is desirable that the absorptivity of the blue light emitting phosphor at a wavelength of 370 to 420 nm is lower than the absorptance of the red light emitting phosphor and the green light emitting phosphor at a wavelength of 370 to 420 nm. In such a wavelength converter, irregular reflection can be efficiently performed by setting the absorption rate of the blue light emitting phosphor particles low.

  Since the wavelength converter 19 can uniformly disperse and carry the phosphor and can suppress light deterioration of the phosphor, the wavelength converter 19 is formed by dispersing the phosphor in a transparent matrix such as a polymer resin or a glass material. It is preferable. As a glass material such as a polymer resin film or a sol-gel glass thin film, a material having high transparency and durability that is not easily discolored by heating or light is desirable.

  The material of the polymer resin film is not particularly limited. For example, epoxy resin, silicone resin, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, cellulose acetate, polyarylate, Derivatives of these materials are used. In particular, it is preferable to have high light transmittance in a wavelength region of 350 nm or more. In addition to such transparency, a silicone resin is more preferably used from the viewpoint of heat resistance.

  Examples of the glass material include silica, titania, zirconia, and composite materials thereof. Compared to a polymer resin film, it has a high durability against light, particularly ultraviolet rays, and further has a high durability against heat, so that the product life can be extended. In addition, since the glass material can improve stability, a highly reliable light-emitting device can be realized.

  The wavelength converter 19 can be formed by a coating method using a glass material such as a sol-gel glass film or a polymer resin film. Although it will not be limited if it is a general coating method, the application | coating by a dispenser is preferable. For example, it can be produced by mixing a phosphor with a liquid uncured resin, a glass material, or a resin and a glass material plasticized with a solvent. As the uncured resin, for example, a silicone resin can be used. These resins may be of a type that is cured by mixing two liquids, or a type that is cured by one liquid. The body may be kneaded, or the phosphor may be kneaded in either one of the liquids. In addition, as a resin made plastic with a solvent, for example, an acrylic resin can be used.

  The cured wavelength converter 19 can be obtained by forming into a film shape by using a coating method such as a dispenser in an uncured state, or pouring into a predetermined mold and hardening. As a method of curing the resin and the glass material, there are a method of using heat energy and light energy, and a method of volatilizing the solvent.

  The conductor forming the electrode 13 has a function as a conductive path for electrically connecting the light emitting element 17, is drawn from the lower surface of the base body 15 to the upper surface, and is electrically connected to the light emitting element 17 by the wire 22. Has been. As the conductor, for example, a metallized layer containing metal powder such as W, Mo, Cu, or Ag can be used. When the substrate 15 is made of ceramic, the conductor is formed on the upper surface of the wiring conductor by heat-treating a metal paste made of tungsten (W) or molybdenum (Mo) -manganese (Mn) or the like at a high temperature. In this case, a lead terminal made of copper (Cu) or iron (Fe) -nickel (Ni) alloy or the like is molded and fixed inside the substrate 15.

  Since the substrate 15 is required to have high thermal conductivity and high total reflectance, for example, a polymer resin in which metal oxide fine particles are dispersed is suitably used in addition to a ceramic material such as alumina or aluminum nitride. .

  The light-emitting element 17 uses a light-emitting element including a semiconductor material that emits light having a center wavelength of 370 to 420 nm because phosphors can be efficiently excited. As a result, it is possible to increase the intensity of the output light and obtain a light emitting device with higher luminous efficiency.

The light emitting element 17 preferably emits the center wavelength. However, the light emitting element substrate has a structure (not shown) including a light emitting layer made of a semiconductor material on the surface of the light emitting element substrate in that it has high quantum efficiency. preferable. Examples of such semiconductor materials include various semiconductors such as ZnSe and nitride semiconductors (GaN and the like), but the type of the semiconductor material is not particularly limited as long as the emission wavelength is in the above wavelength range. A stacked structure including a light-emitting layer made of a semiconductor material may be formed over a light-emitting element substrate using a crystal growth method such as a metal organic chemical vapor deposition method (MOCVD method) or a molecular beam epitaxial growth method. In order to form a nitride semiconductor with good crystallinity with high productivity, for example, when a light emitting layer made of a nitride semiconductor is formed on the surface of the light emitting element substrate, sapphire, spinel, SiC, Si, ZnO, ZrB ₂ , GaN Alternatively, a material such as quartz is preferably used.

  If necessary, a reflecting member 21 that reflects light is provided on the side surfaces of the light emitting element 17 and the wavelength converter 19, and the light escaping to the side surface can be reflected forward to increase the intensity of the output light. Examples of the material of the reflecting member 21 include aluminum (Al), nickel (Ni), silver (Ag), chromium (Cr), titanium (Ti), copper (Cu), gold (Au), iron (Fe), and these. These laminated structures and alloys, ceramics such as alumina ceramics, or resins such as epoxy resins can be used.

  The light-emitting device of this embodiment is obtained by installing the wavelength converter 19 on the light-emitting element 17 as shown in FIG. As a method of installing the wavelength converter 19 on the light emitting element 17, it is possible to install the cured sheet-like wavelength converter 19 on the light emitting element 17.

  The lighting device of the present invention is configured by arranging a plurality of light emitting devices as shown in FIG. 1 on a substrate, for example, and electrically connecting these light emitting devices. Further, a plurality of light emitting elements 17, a wavelength converter 19, and a reflecting member 21 are formed on the surface of the substrate 15 to form a plurality of light emitting devices, and these light emitting devices are electrically connected to form an illumination device. Also good.

The wavelength converter is configured by dispersing a red light emitting phosphor, a blue light emitting phosphor, and a green light emitting phosphor in a transparent matrix.
(Description of red-emitting phosphor)
The red light-emitting phosphor is made of a phosphor having an average particle diameter D50 of ₁₅ to 25 μm, and the average particle diameter can be measured by a laser diffraction scattering method. The quantum efficiency of the red light emitting phosphor is 35 to 45%.

The red light-emitting phosphor is made of an alkaline earth metal silicate and contains, for example, M ¹ (M ¹ is Ba, Ba and Sr, or Ba and Ca), Eu, Mg, Mn, and Si as essential components. It is a phosphor. And the molar ratio of Eu with respect to 1 mol of Si is 0.14 or less, and the molar ratio of Mn with respect to 1 mol of Si is 0.07 or less.

Red-emitting phosphor, for ^{_{example, M 1 3-a Eu a}} Mg 1-b Mn b chemical composition of _Si c _{O 8} (provided that, a 0 <a ≦ 0.264, b is 0 <b ≦ 0.132 , C is a value satisfying 1.905 ≦ c ≦ 2.025). The phosphor represented by this chemical composition is close to the stoichiometric composition, so that crystals capable of converting excitation light into red can be formed with good reproducibility, and the crystal phase can be easily controlled. Generation of converted light other than red can be suppressed.

Molar ratio a of Eu ^is in _{M 1 3-a Eu a Mg} 1-b Mn b Si c O 8 0 < should satisfy a ≦ 0.264. However, if the molar ratio a of the luminescent center ion Eu ²⁺ is too small, the quantum efficiency tends to be small. On the other hand, if the amount is too large, the quantum efficiency tends to decrease due to a phenomenon called concentration quenching. The lower limit is preferably 0.06 ≦ a. In particular, a is preferably in the range of 0.1 ≦ a ≦ 0.2.

The molar ratio of Mn should satisfy 0 <b ≦ 0.132. However phosphor energy Eu ²⁺ excited by irradiation of the excitation light source is moved to Mn ^2+, because the Mn ²⁺ is believed to have red light emission, the degree of energy transfer varies depending on the composition of the Mn . Therefore, in order to obtain high red quantum efficiency, it is preferable that 0.01 ≦ b ≦ 0.1. Further, b preferably satisfies 0.075 ≦ b ≦ 0.1.

  Further, c may satisfy 1.905 ≦ c ≦ 2.025.

The red light-emitting phosphor has a chemical composition of M ¹³ _-xy Eu _x MgMn _y Si _z O ₈ (where x is 0 <x ≦ 0.2, y is 0 <y ≦ 0.1, z Is a value satisfying 1.905 ≦ z ≦ 2.025).

The red light emitting phosphor is an M ¹ ₃ MgSi ₂ O ₈ crystal whose main crystal contains Eu and Mn, and is detected at 2θ = 31.5 ° to 33 ° of the M ¹ ₃ MgSi ₂ O ₈ crystal. The X-ray diffraction intensity of the peak is A, and the X-ray diffraction intensity of the peak detected at 2θ = 27.7 ° to 29.2 ° of the M ¹ ₂ MgSi ₂ O ₇ crystal is B, and M ¹ ₂ SiO ₄ The X-ray diffraction intensity of the peak detected at 2θ = 29.2 ° to 30.8 ° of the crystal is C, and the peak detected at 2θ = 28.0 ° to 29.4 ° of the M ¹ MgSiO ₄ crystal When the X-ray diffraction intensity is D, it is desirable that B / (A + B + C + D) is 0.1 or less, C / (A + B + C + D) is 0.1 or less, and D / (A + B + C + D) is 0.26 or less.

The red light-emitting phosphor is mainly composed of M ¹ ₃ MgSi ₂ O ₈ crystal containing Eu and Mn, and Eu and Mn function as an activator that absorbs excitation light and emits light. . Here, the main crystal is one whose A / (A + B + C + D) is larger than 0.5, but is particularly larger than 0.695, and further, 0.74 or more.

Thus, a phosphor having B / (A + B + C + D) of 0.1 or less, C / (A + B + C + D) of 0.1 or less, and D / (A + B + C + D) of 0.26 or less has Eu and Mn Green light emission other than the M ¹ ₃ MgSi ₂ O ₈ crystal contained as an activator can be suppressed, and a phosphor with high red quantum efficiency can be obtained.

On the other hand, when B / (A + B + C + D) and C / (A + B + C + D) are larger than 0.1 and D / (A + B + C + D) is larger than 0.26, the red quantum efficiency is lowered. In particular, it is desirable that B / (A + B + C + D) is 0.0709 or less and C / (A + B + C + D) is 0.0336 or less. It is desirable that the M ¹ ₂ MgSi ₂ O ₇ crystal and the M ¹ ₂ SiO ₄ crystal do not substantially exist or have a smaller production amount.

For the M ¹ MgSiO ₄ crystal, by satisfying 0.04 ≦ D / (A + B + C + D) ≦ 0.26, the M ¹ ₃ MgSi ₂ O ₈ crystal alone or D / (A + B + C + D) is 0.04 On the contrary, the quantum efficiency of the red light-emitting phosphor can be improved as compared with the case where it is small. The value of D / (A + B + C + D) is preferably 0.08 to 0.25 from the viewpoint of improving the red quantum efficiency.

In the red light emitting phosphor, as shown in FIG. 2, M ¹ ₃ MgSi ₂ O ₈ crystal containing Eu and Mn is used as a main crystal, and M ¹ MgSiO ₄ crystal is formed as the second phase. M ¹ ₂ MgSi ₂ O ₇ crystal and M ¹ ₂ SiO ₄ crystal may be formed as described above. As described above, the M ¹ ₂ MgSi ₂ O ₇ crystal and the M ¹ ₂ SiO ₄ crystal are substantially used. It is desirable that it does not exist or the amount produced is small. Incidentally, FIG. 2 ^shows a M 1 MgSiO ₄ powder X-ray diffraction measurement results of the plurality of phosphors crystal amount is increased or decreased.

As shown in FIG. 3, the red light emitting phosphor has M ¹ MgSiO ₄ crystal particles in M ¹ ₃ MgSi ₂ O ₈ crystal particles. By using such a structure, the present inventors can sufficiently transfer energy absorbed by M ¹ MgSiO ₄ to the M ¹ ₃ MgSi ₂ O ₈ crystal, and the quantum efficiency of the red light emitting phosphor is improved. I think it will improve.

M ¹ includes Ba, Ba and Sr, or a combination of Ba and Ca. Ba is particularly desirable.

When M ¹ is Ba, M ¹ ₃ MgSi ₂ O ₈ containing Eu and Mn has an X-ray diffraction intensity of a peak detected at 2θ = 31.5 ° to 32 ° as A, and M ¹ ₂ MgSi ₂ the X-ray diffraction intensity of the peak detected at 2θ = 27.7 ° ~28.2 ° in O ₇ crystals by ^B, is detected by 2θ = 29.2 ° ~29.8 ° of _M 1 2 SiO ₄ crystal Let X be the X-ray diffraction intensity of the peak, and D be the X-ray diffraction intensity of the peak detected at 2θ = 28.0 ° to 28.4 ° of the M ¹ MgSiO ₄ crystal.

When ^{M 1} is a combination of a Ba, and Sr or Ca, each of the peaks, ^{M 1} ₃ MgSi ^{which M 1} is moved slightly to the higher angle than when the Ba, containing Eu and Mn _{The 2} O ₈ crystal is 2θ = 32.0 ° to 33 °, the M ¹ ₂ MgSi ₂ O ₇ crystal is 2θ = 28.2 ° to 29.2 °, and the M ¹ ₂ SiO ₄ crystal is 2θ = 29.7. ° 30.8 °, M ¹ MgSiO ₄ crystals are detected at 2θ = 28.7 ° to 29.4 °.

The red light-emitting phosphor is composed of Ba, Sr, Ca, Mg, Eu, Mn, and Si element source compounds and, if necessary, a flux such as ammonium chloride, barium chloride, or strontium chloride using the following (A) or ( The mixture prepared by the mixing method of B) is calcined, heat-treated in a reducing atmosphere, washed, dried and sieved to produce a phosphor comprising an aggregate of powders having a D ₉₀ of 50 μm or less. it can. Incidentally, refer to the particle diameter when the fine side in a cumulative particle size distribution of the cumulative 90% and D _90.

  (A): A dry mixing method using a dry pulverizer such as a hammer mill, a roll mill, a ball mill or a jet mill.

  (B): A wet mixing method in which water or the like is added and mixed by a pulverizer in a slurry state or a solution state, and dried by spray drying, heat drying, natural drying or the like.

  Among these mixing methods, particularly in the case of activator elemental compounds, it is preferable to use a liquid medium because it is necessary to uniformly mix and disperse a small amount of the whole compound, and in other elemental compounds, The latter wet mixing method is preferable from the viewpoint of obtaining uniform mixing throughout.

  The calcination method is performed by heating in a heat-resistant container such as a crucible or tray made of alumina or quartz, alone or in a mixed atmosphere of a gas such as oxygen or nitrogen.

  The heat treatment is performed by heating at 1000 ° C. to 1300 ° C. in a mixed atmosphere of oxygen, hydrogen and nitrogen for 1 to 24 hours in a heat-resistant container such as a crucible or tray made of alumina or quartz.

  Further, in order to suppress evaporation of the constituent components during the heating process, filling and microwave baking may be performed.

  In order to satisfy 0.04 ≦ D / (A + B + C + D) ≦ 0.26, it is possible to control the composition of the phosphor, but the calcining temperature of the mixture, calcining time, heat treatment temperature in a reducing atmosphere By changing the conditions for the heat treatment time, it can be controlled to satisfy 0.04 ≦ D / (A + B + C + D) ≦ 0.26 even with the same composition.

The combination of the calcination temperature and the reduction heat treatment temperature is 950 ° C. ≦ calcination temperature ≦ 1250 ° C., 1150 ° C. ≦ reduction heat treatment temperature ≦ 1250 ° C. The calcining temperature holding time is preferably 1 to 6 hours, and the reducing heat treatment holding time is 1 to 12 hours. When the combination of the calcination temperature and the reduction heat treatment temperature is too high, a large amount of the second phase BaMgSiO ₄ crystal is precipitated and emits green light, thereby reducing the red quantum efficiency. On the other hand, when the calcining temperature is too low, the precipitation amount of the second phase BaMgSiO ₄ crystal is small, energy transfer is small, and the quantum efficiency improvement effect is small.
(Description of green light emitting phosphor)
The green light-emitting phosphor of the present invention is made of a phosphor having an average particle diameter D50 of ₁₅ to 25 μm, and the average particle diameter can be measured by a laser diffraction scattering method. The quantum efficiency of the green light emitting phosphor is 40 to 50%.

The green light-emitting phosphor of the present invention is made of an alkaline earth metal silicate, contains a plurality of phosphor particles, M ² (M ² is at least one selected from Sr, Ba and Ca), Eu. And a phosphor containing Si. This green light-emitting phosphor has a crystal represented by (M ² , Eu) ₂ SiO ₄ as a main crystal, and is 2 according to the X-ray absorption near edge structure (XANES) of the green light-emitting phosphor. The concentration of divalent Eu ions with respect to the total amount of valent Eu ions and trivalent Eu ions is 90% or more.

Furthermore, the phosphor has a molar ratio of ^{M 2} for Si 1 mol, the sum of the molar ratio of Eu for Si 1 mole ^{((M 2 + Eu) /} Si) is less than 2.

That is, in the phosphor represented by Sr _2-xy Ba _x Eu _y SiO ₄ in Patent Document 2, the sum of the molar ratios of Sr, Ba, and Eu with respect to 1 mol of Si (also simply referred to as the sum of the molar ratios). (Sr + Ba + Eu) / Si is 2, but the concentration of the divalent Eu ion is 90% or more with respect to the total amount of the divalent Eu ion and the trivalent Eu ion, that is, Eu ²⁺ / (Eu ²⁺ + Eu ³⁺ ) In the region of ≧ 0.9, the sum of the molar ratios (Sr + Ba + Eu) / Si is made smaller than 2 and further set to 1.94 or less. Luminous efficiency superior to the total (Sr + Ba + Eu) / Si = 2 phosphor can be realized.

The value of the total molar ratio (Sr + Ba + Eu) / Si referred to here is not a value obtained from the constituent element composition of the Sr _2-xy Ba _x Eu _y SiO ₄ crystal in the phosphor, but the configuration of the entire green light emitting phosphor. The value obtained from the elemental composition.

In an ideal (M ² , Eu) ₂ SiO ₄ crystal that emits fluorescence, for example, Sr _2−xy Ba _x Eu _y SiO ₄ crystal, the stoichiometric ratio is the sum of the molar ratios (Sr + Ba + Eu) / Si = 2. Therefore, although it seems desirable that the composition of the phosphor is also the sum of the molar ratio (Sr + Ba + Eu) / Si = 2, the reason is currently unknown, but rather the sum of the molar ratio (Sr + Ba + Eu) The total molar ratio of phosphors (Sr + Ba + Eu) / the total molar ratio deviating from the stoichiometric ratio (Sr + Ba + Eu) / Si <2, in particular 1.94 or less, It has been clarified that a phosphor having a high quantum efficiency can be obtained by setting the range of 1.78 to 1.94. In particular, it is desirably 1.89 to 1.91.

  Further, the value of x can be arbitrarily selected within the range of 0 to 1. When x = 0, it can be yellow, and when x = 1, it can be a green phosphor. Yellow to green (hereinafter, yellow) (It may be green). Here, water resistance can be improved by setting x ≦ 1.

The concentration of the divalent Eu ion with respect to the total amount of the divalent Eu ion and the trivalent Eu ion (hereinafter sometimes simply referred to as a divalent Eu ion concentration) is Eu ²⁺ / (Eu ²⁺ + Eu ³⁺ ) ≧ 0 .9. The divalent Eu ion concentration is desirably 96% or more.

The divalent Eu ion concentration and the trivalent Eu ion concentration can be measured by XANES of the phosphor. For example, the ratio of Eu ^{2+ to} the total Eu is Eu-L3 absorption edge as shown in FIG. It can be calculated by measuring the XANES spectrum. XANES is a general term for resonance absorption peaks appearing at and near the characteristic absorption edge of each element, and sensitively reflects the valence and structure of the element.

In general, it is known that the strong resonance peak energy appearing in the L3 absorption edge XANES spectrum of rare earth is determined by the valence of the rare earth element. In the case of Eu, the Eu ²⁺ peak has an energy about 8 eV lower than the Eu ³⁺ peak. It is possible to separate and quantify the two. Peak height and ^Eu 2+, assuming the concentration of ^{Eu 3+} is proportional, to define the occupied ion concentration ^{Eu 2+} as ^{(Eu 2+} peak height) / ^{(Eu 2+} peak height + ^{Eu 3+} peak height) .

In order to make Eu ²⁺ / (Eu ²⁺ + Eu ³⁺ ) ≧ 0.9, for example, when Eu ³⁺ such as europium oxide is used as a raw material, heat treatment is performed in a strong reducing atmosphere, and sufficient time is required for the treatment. That's fine. Thus, the quantum efficiency of the phosphor can be increased by increasing the Eu ²⁺ ratio.

However, since this process takes time, the heat treatment is generally completed using a flux for a short time. Preferable fluxes include halides such as SrCl ₂ , BaCl ₂ , NH ₄ Cl and SrF _2, and alkali compounds such as NaOH and KOH. In particular, SrCl ₂ is desirable.

  The flux can be easily removed by washing with water after the phosphor is synthesized. When the flux is not used, there is an advantage that this washing step is unnecessary, but the quantum efficiency tends to be lower than when the flux is used.

  The composition of the green light-emitting phosphor when the flux is removed is determined by the ratio of Sr, Ba, Eu, and Si as raw materials to be added to remove Sr, Ba, Eu, and Si. Except for, there is almost no change before and after heat treatment.

The green light emitting phosphor is represented by the formula (M ² , Eu) ₂ SiO ₄ (M ² is at least one selected from Sr, Ba and Ca), and the phosphor particles constituting the green light emitting phosphor Is excited by light of around 400 to 460 nm and emits fluorescence of 520 nm to 570 nm.

  In the green light-emitting phosphor, as shown in FIGS. 5 and 6, the phosphor particles have a large number of inorganic fibrous bodies 5a on the surface of the phosphor core 5b, and at least one end of the phosphor particles is phosphor. It is embedded in the core 5b and fixed to the surface of the phosphor core 5b. The fibrous body 5a can also be seen as if the needle-like short fibers are folded several times when the phosphor core 5b is viewed in the diameter direction (FIG. 5).

  And the front-end | tip part of the fibrous body 5a is embed | buried and used as the embed | buried part, and non-buried parts other than this embed | buried part are spaced apart from the surface of the fluorescent substance core 5b with the predetermined space | interval h. This interval h is filled with the resin when the phosphor particles are dispersed in the resin.

  The fluorescence peak wavelength is on the low wavelength side when Ba with a large atomic radius is used, and on the long wavelength side with use of Ca with a small atomic radius, and the wavelength can be controlled by the mixing ratio of Ba, Sr, and Ca.

Hereafter, the manufacturing method of the green light emission fluorescent substance of this invention is demonstrated. A compound containing elements of Sr, Ba, Ca, Eu, Si, for example, strontium carbonate, barium carbonate, calcium carbonate, europium oxide, silica powder, the molar ratio of each element is, for example, Eu / Si = 0.01- Each powder is weighed so that 0.1, (M ² + Eu) /Si=1.78 to 1.94, and a phosphor material to be a phosphor is prepared.

  As the phosphor raw material, for example, oxides, carbonates, nitrates, sulfates, halides and hydroxides that easily become oxides during the firing treatment can be suitably used. Below, the manufacturing method of the fluorescent substance containing Ba, Sr, Si, and Eu is demonstrated.

  As the calcium raw material, for example, calcium oxide, calcium hydroxide, calcium carbonate, calcium chloride, calcium nitrate, calcium sulfate, calcium acetate, calcium oxalate, or calcium alkoxide can be used.

  As the strontium raw material, for example, strontium oxide, strontium hydroxide, strontium carbonate, strontium chloride, strontium nitrate, strontium sulfate, strontium acetate, strontium oxalate, and strontium alkoxide can be used.

  As the barium raw material, for example, barium oxide, barium carbonate, barium chloride, barium nitrate, barium sulfate, barium acetate, barium oxalate, and barium alkoxide can be used.

  Moreover, as a silicone raw material, silicon dioxide, such as quartz and cristobalite, and the alkoxide of silicone can be used, for example.

  In addition, as the europium raw material, for example, europium oxide, europium chloride, and europium fluoride can be used.

  A predetermined amount of these raw materials are weighed and mixed to obtain a phosphor raw material. In order to promote crystal growth and improve emission luminance, 0.1 to 10% by mass of alkali metal halide, alkaline earth metal halide, ammonium halide, boron compound with respect to the phosphor raw material A low-melting-point compound such as is added and mixed as a flux to obtain a raw material mixture. The flux is also called a flux.

  More specifically, the phosphor particles are prepared by adjusting Ba raw material, Sr raw material, Ca raw material, Eu raw material, and Si raw material by the following (A) group or (B) group mixing method. A raw material mixture containing the agent is prepared.

  (A): A dry mixing method using a dry pulverizer such as a hammer mill, a roll mill, a ball mill or a jet mill.

  (B): A wet mixing method in which water or the like is added and mixed by a pulverizer in a slurry state or a solution state, and dried by spray drying, heat drying, natural drying or the like.

  Among these mixing methods, it is particularly preferable to use a liquid medium because a small amount of a compound needs to be uniformly mixed and dispersed throughout, and uniform mixing can be obtained throughout other elemental compounds. From the aspect, the latter wet mixing method is preferable.

  The phosphor of the present invention can be produced by heat-treating the raw material mixture thus adjusted.

When the raw material mixture is a powder, it is desirable to mix and grind the average particle size of the raw material mixture powder to 1 μm or less. This is because, by adding a flux and heat-treating in an oxidizing atmosphere, apatite-type crystal powder can be sufficiently produced, and since it is a fine powder, the production rate of apatite-type crystal powder containing Eu is increased and substantially increased. A mixed powder comprising an apatite type crystal powder containing Eu and a base material particle powder represented by the formula M ² ₂ SiO ₄ (M ² is at least one selected from Sr, Ba and Ca) Is possible. In order to mix and pulverize the average particle diameter of the raw material mixed powder to 1 μm or less, it is necessary to lengthen the mixing time, pass the mixed and pulverized raw material mixed powder through a mesh, and eliminate abnormal agglomerated powder.

  The heat treatment temperature of the raw material mixed powder in an oxidizing atmosphere is preferably 1000 to 1100 ° C. and preferably 2 to 5 hours. This is because the apatite-type crystal powder is generated at 1000 ° C. or higher, but if it exceeds 1100 ° C., the base material particles grow, which is not preferable.

By the heat treatment in the oxidizing atmosphere, Eu substantially enters the apatite-type crystal and the amount existing as Eu ₂ O ₃ can be reduced, and the mixture is composed of the apatite-type silicate powder containing Eu and the base material particle powder. A powder can be made. Note that Eu also partially enters the base material particles.

The apatite-type crystal is an apatite-type silicate represented by (BaSr) _{2 + x} Eu _8-x (SiO ₄ ) ₆ Cl _4-x , and Eu exists as trivalent. FIG. 7 is a transmission electron microscope (TEM) photograph after heat treatment in an oxidizing atmosphere. In FIG. 7, it can be seen that the apatite-type crystals are present in the base material particle powder or around the base material particle powder. It can also be seen that the apatite-type crystals are much smaller than the particle size of the base material particles. FIG. 8 shows the X-ray diffraction measurement results. From this X-ray diffraction measurement result and TEM photograph, it can be seen that a mixed powder composed of Eu-containing apatite-type silicate powder and base material particle powder can be produced by heat treatment in an oxidizing atmosphere. Incidentally, FIG. 8 is a case of increasing the amount of _Eu 2 _{O 3.}

  After heat treatment in an oxidizing atmosphere, a mesh pass is performed. For example, heat-treated powder of 75 μm or less is heat-treated in a reducing atmosphere.

  Although it is a mixed powder composed of Eu-containing apatite-type crystal powder and base material particle powder, and the fine mixed powder without abnormal agglomerated powder is heat-treated in a reducing atmosphere, the reason is not clear. Valent Eu ions are easily reduced to divalent Eu ions, and Sr and Ba of the base material particles and Eu in the apatite-type crystal are mutually substituted, so that the concentration of the divalent Eu ions of the phosphor is 96% or more. Can be high. The apatite type crystals become phosphor particles by mutual substitution.

  The heat treatment temperature in a reducing atmosphere is preferably 1000 to 1300 ° C., and the treatment time is preferably 3 to 12 hours. Thereafter, the phosphor particles can be obtained by washing with distilled water.

  The composition ratio of the constituent elements of the phosphor can be measured by a technique such as ICP emission spectroscopic analysis.

  Further, after heat treatment in an oxidizing atmosphere, heat treatment is performed in a reducing atmosphere, particularly at a low temperature of 1150 ° C. or lower, and washing is performed, so that an inorganic fibrous fiber is formed on the surface of the phosphor core 5b as shown in FIGS. Many bodies 5a can exist.

  This is because when the heat treatment temperature in the reducing atmosphere is high, crystallization proceeds and it is difficult to form the fibrous body 5a even after washing. In particular, 1000 to 1150 ° C is desirable.

  The inorganic fibrous body 5a can be formed on the surface of the phosphor core 5b by, for example, heat treatment in a reducing atmosphere and then washing with distilled water. The time for washing with distilled water is 5 to 24 hours, and the temperature of the washing liquid is preferably 10 to 50 ° C.

According to the present inventors, the fibrous body is a crystal formed by heat treatment in a reducing atmosphere, and since the heat treatment temperature in the reducing atmosphere is low, the entire phosphor core cannot be crystalline, and the fibrous body It is considered that an amorphous body containing M ² , Si, and Eu exists around the crystal, and the amorphous body in the phosphor core is dissolved and the fibrous body is exposed by washing. .

  In order to expose a part of the fibrous body, it is desirable to use water as the cleaning liquid. It is considered that the water cleans the flux and hydrolyzes particularly the amorphous portion of the phosphor core to expose the fibrous body.

And the fluorescent substance core component which is easy to melt | dissolve in distilled water elutes from the surface by a washing | cleaning process, the fibrous body 5a is exposed, and also the front-end | tip part of the fibrous body 5a becomes the fluorescent substance core 5b by extending cleaning time. However, a portion not embedded (non-embedded portion) can be shaped to be spaced from the surface of the phosphor core 5b with a predetermined interval h. According to the present inventors, the phosphor core component is composed of (M ² , Eu) ₂ SiO ₄ (M ² is at least one selected from Sr, Ba and Ca), and the eluted component is an amorphous part. The fibrous body 5a is considered to be made of a crystalline material. That is, the fibrous body 5a is made of an inorganic material and is considered to be made of a crystalline material represented by (M ² , Eu) ₂ SiO ₄ (M ² is at least one selected from Sr, Ba and Ca). .

  Further, since the fibrous body 5a is exposed by washing, the exposed portion of the core side part may be embedded in the phosphor core 5b, and the washing is made longer and exposed except for both ends. Although the portion may be in a state of being separated from the core surface, at least one end of the fibrous body 5a is embedded. In addition, as described in the right side of FIG. 6, the middle of one fibrous body 5a may be embedded in the core, and when viewed from the diameter direction of the core surface, it looks like a plurality of fibrous bodies. Therefore, it is represented as a plurality of fibrous bodies.

  In addition, since the inorganic fibrous body 5a can exhibit an anchor effect with the cured resin, the adhesion between the resin and the phosphor particles 5 is improved, and peeling occurs between the two. Can be suppressed. As a result, the wavelength converter in which the phosphor particles 5 of the present invention are dispersed in a transparent matrix made of resin and the light emitting device using the wavelength converter are suppressed from whitening even with long-term use and have a long lifetime. It becomes.

The inorganic fibrous body 5a is preferably formed so that the height from the surface of the phosphor core 5b is 50 nm or more, particularly 100 nm or more. As described above, the firing is performed in a reducing atmosphere. By controlling the washing time with distilled water in the washing step, the size and amount of the inorganic fibrous body 5a can be appropriately controlled. That is, when sintering in a reducing atmosphere is strengthened to some extent, the amount of the fibrous body 5a is increased, the size is increased, and the length of the fibrous body 5a can be increased by increasing the cleaning time. . Needless to say, the height of the fibrous body 5a can be measured by analysis using a reflection electron microscope.
(Description of blue-emitting phosphor)
Blue-emitting phosphor of the present invention has an average particle diameter D ₅₀ consists of phosphor 3 to 10 [mu] m, average particle size can be measured by a laser diffraction scattering method. The quantum efficiency of the blue light emitting phosphor is 35 to 45%.

Blue-emitting phosphors are (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₁₇ : Eu, Sr ₁₀ (PO _{4) 6 Cl 12: Eu,} 10 (Sr, Ca, Ba, Eu) · 6PO 4 · Cl 2, (Sr, Ca, Ba, Mg) 5 (PO 4) 3 (Cl, Br): Eu, and the like Used. The blue phosphor is a halophosphate represented by [(M, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu,] (M is at least one selected from Ca, Sr and Ba). Is preferably used.

  In the wavelength converter of the present invention, the quantum efficiency of the phosphor that emits blue light is higher than the quantum efficiency of the phosphor that emits red light and the phosphor that emits green light, and the average particle size of the phosphor that emits blue light The diameter is smaller than the average particle diameter of the phosphor that emits red light and the phosphor that emits green light.

  As a result, the average particle size of the blue light-emitting phosphor with high quantum efficiency is smaller than that of other phosphors. The green light emitting phosphor and the red light emitting phosphor and the green light emitting phosphor are absorbed, so that the quantum efficiency of the red light emitting phosphor and the green light emitting phosphor can be improved.

  A certain degree of effect can be obtained if the quantum efficiency of the phosphor that emits blue light is higher than the quantum efficiency of the phosphor that emits red light and the phosphor that emits green light. In addition, a certain effect can be obtained if the average particle diameter of the phosphor emitting blue light is smaller than the average particle diameter of the phosphor emitting red light and the phosphor emitting green light, but it is particularly small by 5 μm or more. It is desirable.

(Production of red light emitting phosphor 1)
Using barium carbonate powder, magnesium oxide powder, strontium carbonate powder, calcium carbonate powder, silicon dioxide powder, europium oxide powder and manganese oxide powder, zinc acetate powder, and germanium dioxide powder, the molar ratios shown in Table 1 are shown. In a polypot, the mixture was dried, and then calcined at 1150 ° C. for 3 hours in an air atmosphere.

Then, heat treatment was performed by heating at 1250 ° C. for 9 hours under a nitrogen gas flow containing 12% hydrogen, washing, drying, and sieving to produce a phosphor comprising an aggregate of powders having a D ₉₀ of 50 μm or less. did.

Sample No. In 1-16, M ^{1 is set} to a molar ratio of strontium carbonate: barium carbonate = 0.15: 0.85, the main crystal is (Ba, Sr) ₃ MgSi ₂ O ₈ , and the heterogeneous phase is (Ba, Sr ) ₂ SiO ₄ and sample no. In 1-17, M ^{1 is set} to a molar ratio of calcium carbonate: barium carbonate = 0.15: 0.85, the main crystal is (Ba, Ca) ₃ MgSi ₂ O ₈ , and the different phase is (Ba, Ca) _2. SiO ₄ .

  Sample No. In No. 1-18, the molar ratio was zinc acetate: magnesium oxide = 0.15: 0.85. In 1-19, it was set as germanium dioxide: silicon dioxide = 0.15: 0.85 by molar ratio.

  Sample No. The phosphors 1-1 to 19 are produced without using a so-called flux.

  The X-ray diffraction measurement of the phosphor produced in the above process was performed under the following conditions. That is, using a powder X-ray diffractometer (MAC M18XCE manufactured by Mac Science Co., Ltd.) comprising an X-ray source of (Cu-Kα) whose diffraction angle error in the scanning range is optically adjusted to Δ2θ = 0.05 ° or less, and a sample The powder X-ray diffraction measurement was performed under the condition that the angle reproducibility of Δ2θ = 0.05 ° or less was ensured using the 111 peak of standard silicon where the diffraction angle error due to eccentricity was 111.

And the X-ray diffraction intensity of the peak detected at 2θ = 31.5 ° to 32 ° of Ba ₃ MgSi ₂ O ₈ which is the main crystal containing Eu and Mn as an activator is A, and Ba ₂ MgSi ₂ O _The peak detected at 2θ = 27.7 ° to 28.2 ° of ₇ crystals is B, and the peak detected at 2θ = 29.2 ° to 29.8 ° of the Ba ₂ SiO ₄ crystal is B. The peak of the main crystal is A / (A + B + C + D) where D is the X-ray diffraction intensity of the peak detected from 2θ = 28.0 ° to 28.4 ° of the BaMgSiO ₄ crystal, where C is X-ray diffraction intensity Intensity ratio, B / (A + B + C + D) is the peak intensity ratio of Ba ₂ MgSi ₂ O ₇ crystal, C / (A + B + C + D) is the peak intensity ratio of Ba ₂ SiO ₄ crystal, and D / (A + B + C + D) is BaMgSiO ₄ crystal Peak strength It described in Table 2 as a ratio. No. For 1-16 and 17, the peak moves slightly higher.

  Further, the quantum efficiency of the obtained phosphor was measured using a spectrofluorometer FP-6500 manufactured by JASCO Corporation. The quantum efficiency of the phosphor was measured by filling a dedicated cell with phosphor powder and irradiating with excitation light of 395 nm and measuring the fluorescence spectrum. The red quantum efficiency was calculated from the results using the quantum efficiency measurement software attached to the spectrofluorometer, and the results are shown in Table 2. -In the column of the peak ratio in Table 2 means that the peak was not found visually in the X-ray diffraction measurement result.

In FIG. The X-ray diffraction pattern of 1-2 is shown. Further, in FIG. The X-ray diffraction pattern of 1-7 is shown. The vertical axis in the figure represents the X-ray diffraction intensity and is represented by a relative value with the maximum value being 1. The horizontal axis is the diffraction angle. No. In 1-7, a peak was confirmed at 2θ = 28.0 ° to 28.4 °, and precipitation of BaMgSiO ₄ crystals was confirmed.

On the other hand, no. 2 shows that peaks derived from Ba ₂ MgSi ₂ O ₇ crystal, Ba ₂ SiO ₄ crystal, and BaMgSiO ₄ crystal are very small, and the precipitation of these crystals is suppressed, and the target crystals are precipitated accurately. confirmed.

In the sample according to the present invention, since precipitation of M ¹ ₂ MgSi ₂ O ₇ crystal, M ¹ ₂ SiO ₄ crystal, and M ¹ MgSiO ₄ crystal is suppressed, generation of green light is suppressed, and red quantum efficiency is reduced. It turns out to be high.

Furthermore, it can be seen that a quantum efficiency of 35% or more can be obtained particularly in a sample where D / (A + B + C + D) is in the range of 0.04 to 0.26.
(Production of red-emitting phosphor 2)
Barium carbonate powder and magnesium oxide powder, silicon dioxide powder, europium oxide powder, manganese oxide powder, ammonium chloride powder as a flux, weighed to the composition shown in Table 3, mixed in a polypot, dried, air Calcination was performed at 1150 ° C. for 3 hours in an atmosphere. Thereafter, heat treatment was performed by heating for 9 hours at 1250 ° C. under a nitrogen gas flow containing 12% hydrogen to produce a phosphor.

  In the same manner as described above, the peak intensity ratio and the quantum efficiency of the phosphor were determined and listed in Table 4.

From these Tables 3 and 4, in the sample according to the present invention, since the precipitation of Ba ₂ MgSi ₂ O ₇ crystal, Ba ₂ SiO ₄ crystal and BaMgSiO ₄ crystal is suppressed, the generation of green light is suppressed and the red color is reduced. It turns out that the quantum efficiency of becomes high. In particular, it is understood that a quantum efficiency of 35% or more can be obtained in a sample in which D / (A + B + C + D) is in the range of 0.04 to 0.26.
(Production of red-emitting phosphor 3)
In the composition formula of ^{_{M 1 3-a Eu a Mg}} 1-b Mn b Si c O 8, a, b, c are formed so that the value shown in Table 5, barium carbonate powder, magnesium oxide powder, strontium carbonate powder, Prepare silicon dioxide powder, europium oxide powder and manganese oxide powder, add a certain amount of ammonium chloride as a flux, mix in a polypot, dry, and then calcined at the temperature shown in Table 5 for 3 hours in air Then, heat treatment was performed for 9 hours at a temperature shown in Table 5 with nitrogen gas containing 12% hydrogen (in a reducing atmosphere) to produce a phosphor according to the present invention. No. 3-4 samples were used Ba and Sr as ^{M 1.} The main crystal is (Ba, Sr) ₃ MgSi ₂ O ₈ and the second phase is (Ba, Sr) MgSiO ₄ .

A scanning electron microscope (SEM) photograph (1000 times) of the phosphor according to the present invention is shown in FIG. In the sample within the scope of the present invention, the second phase M ¹ MgSiO ₄ crystal particles were present in the M ¹ ₃ MgSi ₂ O ₈ crystal particles.

  The quantum efficiency of the obtained phosphor was measured using a spectrofluorophotometer FP-6500 manufactured by JASCO Corporation. The quantum efficiency of the phosphor was measured by filling a dedicated cell with phosphor powder and irradiating with excitation light of 395 nm and measuring the fluorescence spectrum. The red quantum efficiency was calculated using the quantum efficiency measurement software attached to the spectrofluorometer, and the result is shown in Table 6.

  The X-ray diffraction measurement of the phosphor was performed in the same manner as described above.

From this result, it is assumed that the X-ray diffraction intensity of a peak detected in the vicinity of 2θ = 31.5 ° to 32 ° of the M ¹ ₃ MgSi ₂ O ₈ crystal is A, and 2θ of the M ¹ ₂ MgSi ₂ O ₇ crystal is 27.27. the X-ray diffraction intensity of the peak at 7 ° ~28.2 ° and ^B, and X-ray diffraction intensity of the peak at 2θ = 29.2 ° ~29.8 ° of _M 1 2 SiO ₄ crystal and C, M ^{1 When} the X-ray diffraction intensity of the peak at 2θ = 28.0 ° to 28.4 ° of MgSiO ₄ crystal is D, B / (A + B + C + D), C / (A + B + C + D), D / (A + B + C + D) are obtained. Each is shown in Table 6. Sample No. The 3-4, M ¹ is the peak position is detected by moving slightly higher angle than in the case of Ba.

The sample is substantially composed of the main crystal Ba ₃ MgSi ₂ O ₈ crystal and the second phase BaMgSiO ₄ crystal, and the M ¹ ₂ MgSi ₂ O ₇ crystal and M ¹ ₂ SiO ₄ crystal are substantially absent. It was.

  FIG. 10 shows the relationship between the peak intensity ratio D / (A + B + C + D) of the sample and the red quantum efficiency.

Tables 5 and 6 and FIG. 10 show that in the phosphor, D / (A + B + C + D) is 0.04 to 0.26, energy transfer from the BaMgSiO ₄ crystal occurs efficiently, and red quantum efficiency is high. .

On the other hand, since the phosphor (sample No. 3-13) whose relative value of peak intensity in X-ray diffraction is outside the range of 0.04 to 0.26 has too much precipitation amount of BaMgSiO ₄ crystal, It can be seen that the red quantum efficiency is low.
(Production of green light emitting phosphor 1)
A green-emitting phosphor was produced. First, powders of strontium carbonate, barium carbonate, calcium carbonate, silica, and europium oxide were prepared so that the molar ratio of Sr, Ba, Eu, and Si with respect to 1 mol of Si would be the ratio shown in Table 7. Furthermore, 2 parts by mass of SrCl ₂ as a flux was added to 100 parts by mass of the total amount of these powders to prepare a raw material powder.

  Further, 2-propyl alcohol and zirconia media balls were placed in a polypot to these powders and mixed with stirring for 48 hours.

  The resulting mixed solution was discharged using a nylon mesh having an opening of 190 μm while removing the media balls, and then heated at 110 ° C. for 8 hours to remove 2-propyl alcohol.

Next, the raw material mixed powder from which 2-propyl alcohol was removed was placed in an alumina crucible and heated at 1100 ° C. for 3 hours in an air atmosphere. Then, a green light emitting phosphor having a crystal represented by (M ² , Eu) ₂ SiO ₄ as a main crystal is synthesized by heating at 1200 ° C. for 4.5 to 9 hours in a nitrogen gas flow containing 12% hydrogen. did.

  For the main crystal, a powder X-ray diffractometer (MAC M18XCE manufactured by Mac Science Co., Ltd.) comprising an X-ray source of (Cu-Kα) whose diffraction angle error in the scanning range is optically adjusted to Δ2θ = 0.05 ° or less is used. In addition, an error in diffraction angle due to sample eccentricity was confirmed by performing powder X-ray diffraction measurement under conditions where an angle reproducibility of Δ2θ = 0.05 ° or less was ensured using 111 peaks of standard silicon.

  In addition, a green light emitting phosphor without adding a flux was also produced. And these water-emitting phosphors were washed with water.

The green-emitting phosphor which has been subjected to this washing process was XANES analysis, ^Eu 2+ peak around 6977eV, 2 divalent Eu ion concentration peak in the vicinity of 6985eV as ^{Eu 3+} of ^{(Eu 2+ / (Eu 2+ +} Eu 3+) × 100) The value was determined.

  Further, the green light-emitting phosphor subjected to the water washing treatment was subjected to ICP emission spectroscopic analysis to determine the composition ratio of the green light-emitting phosphor, and the total molar ratio (Sr + Ba + Eu) / Si was determined from the results. Therefore, the composition of the green light-emitting phosphor was omitted.

  Moreover, the quantum efficiency of the obtained green light emission fluorescent substance was measured using JASCO Corporation spectrofluorimeter FP-6500. A dedicated cell was filled with a green-emitting phosphor, irradiated with excitation light of 395 nm, and a fluorescence spectrum was measured. The quantum efficiency was calculated from the results using the quantum efficiency measurement software attached to the spectrofluorometer.

As shown in Table 7, sample no. It can be seen that the phosphors 4-9 and 4-10 have low quantum efficiency. Sample No. In the phosphor of 4-17, the molar ratio (Sr + Ba + Eu) / Si was 2, and the divalent Eu ion concentration was 95%, but the quantum efficiency was as low as 34%. In contrast, sample no. The phosphors 4-1 to 4-8, 4-11 to 4-16, 4-18, and 4-19 exhibited high quantum efficiency.
(Production of green light emitting phosphor 2)
As raw materials, powders of SrCO ₃ , BaCO ₃ , SiO ₂ , Eu ₂ O ₃ were used. As a flux, SrCl ₂ powder was used. 52.3% by mass of SrCO ₃ , 25.5% by mass of BaCO ₃ , 15.0% by mass of SiO ₂ , 2.2% by mass of Eu ₂ O ₃ and 5% by mass of SrCl ₂ with respect to 100 g of the total blending amount. It was prepared at the ratio of The molar ratio of Sr to 1 mol of Si was 1.419, the molar ratio of Ba was 0.518, the molar ratio of Eu was 0.025, and the total molar ratio (Sr + Ba + Eu) / Si was 1.96. It was.

  Then, 200 g of isopropyl alcohol as a solvent was added to these powders, and ball mill mixing was performed for the time shown in Table 8.

Next, isopropyl alcohol used as a solvent was evaporated at 80 ° C., and the dried mixed powder was subjected to # 200 mesh pass (aperture 75 μm) to obtain a raw material mixed powder having an average particle diameter D ₅₀ as shown in Table 8 It was. And this raw material mixed powder was put in the crucible and heat-processed at 1000 degreeC in air | atmosphere for 3 hours.

  Thereafter, the sample No. of the present invention was determined by powder X-ray diffraction measurement using TEM and Cu-kα rays. About 5-1 to 5-4, it confirmed that the powder after an oxidation process consisted of an apatite type silicate powder and base material particle powder.

  Next, these mixed powders were subjected to # 200 mesh pass and then heat-treated at 1200 ° C. for 9 hours in a reducing atmosphere with a hydrogen concentration of 12% (others were nitrogen). Sample No. For 5-6, no reduction treatment was performed.

  The obtained powder was stirred and washed with distilled water having a weight 10 times the weight of the powder for 10 hours, and water was removed with a dryer.

The obtained powder was put into a powder form using a mesh or the like by applying pressure to produce a phosphor. About the obtained fluorescent substance, the divalent ion concentration of fluorescent substance was measured by L3 absorption edge XANES spectrum, and the result was described in Table 8. Further, when the main crystal of the phosphor was determined in the same manner as described above, it was a crystal represented by (M ² , Eu) ₂ SiO ₄ .

  Then, 20% by mass of this phosphor powder was added to an uncured silicone resin, and the silicone resin was cured at a temperature of 150 ° C., thereby producing a wavelength converter having a thickness of 0.8 mm.

  The quantum efficiency of the obtained phosphor was measured using a spectrofluorometer FP-6500 manufactured by JASCO Corporation. A dedicated cell was filled with phosphor powder and irradiated with excitation light of 395 nm, and a fluorescence spectrum was measured. The quantum efficiency was calculated from the results using the quantum efficiency measurement software attached to the spectrofluorometer.

  As shown in Table 8, Sample No. In No. 5-5, since no flux was added, the production of apatite was suppressed, and the divalent ion concentration was 81%. Sample No. In 5-6, a flux was added, but since there was no reduction treatment step, the divalent ion concentration was 0%.

On the other hand, sample No. In 5-1 to 5-4, the mixed powder was refined by addition of a flux and wet mixing, and the mixed powder was subjected to a mesh pass after the oxidation treatment. became. No. FIG. 11 shows L3 absorption edge XANES spectrum results for 5-3, 5-5, and 5-6.
(Production of green light emitting phosphor 3)
As raw materials, powders of SrCO ₃ , BaCO ₃ , SiO ₂ , Eu ₂ O ₃ were used. As a flux, SrCl ₂ powder was used. SrCO ₃ is 52.3% by mass, BaCO ₃ is 25.5% by mass, SiO ₂ is 15.0% by mass, Eu ₂ O ₃ is 2.2% by mass, and SrCl ₂ is 5% by mass with respect to the total blending amount. Formulated in proportions. The molar ratio of Sr to 1 mol of Si was 1.419, the molar ratio of Ba was 0.518, the molar ratio of Eu was 0.025, and the total molar ratio (Sr + Ba + Eu) / Si was 1.96. It was.

  Then, 200 g of isopropyl alcohol as a solvent was added to these powders, and ball mill mixing was performed for 48 hours.

  Next, isopropyl alcohol used as a solvent was evaporated at 80 ° C. to obtain a dried raw material mixed powder. And this raw material mixed powder was put in the crucible and heat-processed at the temperature of 1100 degreeC in air | atmosphere for 3 hours.

  Next, these powders were heat-treated at a temperature shown in Table 9 in a reducing atmosphere having a hydrogen concentration of 12% (others were nitrogen).

  The obtained powder was stirred and washed with distilled water having a weight 10 times the weight of the powder (room temperature) for the time shown in Table 9. Further, the supernatant liquid of the cleaning liquid was removed, and water was removed with a dryer.

The obtained powder was put into a powder form using a mesh or the like by applying pressure to produce a phosphor. When the main crystal of this phosphor was determined in the same manner as described above, it was a crystal represented by (M ² , Eu) ₂ SiO ₄ . Further, when the divalent ion concentration was determined in the same manner as described above, the sample No. 6-1 was 20%, but other samples of the present invention were 90% or more. Then, 20% by mass of this phosphor was added to an uncured silicone resin, and the silicone resin was cured at a temperature of 150 ° C. to produce a wavelength converter having a thickness of 0.8 mm.

  In preparation of these wavelength converters, phosphor particles were mixed with silicone resin, allowed to stand for 30 minutes and then cured, and the presence or absence of fibrous bodies was determined in the precipitation of the phosphor particles and in the produced wavelength converter. The influence on the uneven distribution of the phosphor particles was examined using a reflection electron microscope (SEM). The wavelength converter was cut and the cross section was observed with an SEM to confirm the uneven distribution of the phosphor.

  Moreover, the surface of the obtained phosphor particles was observed by SEM, and the presence or absence of a fibrous body was confirmed. Moreover, the wavelength converter performed the reliability test (-40-125 degreeC cycle) of a temperature cycle, and investigated the presence or absence of generation | occurrence | production of whitening. These results are shown in Table 9.

  From Table 9, Sample No. in which there was no fibrous body 3 outside the scope of the present invention. In 6-1, whitening of the wavelength converter was confirmed when the temperature cycle was 200 cycles. Sample No. Since the reduction temperature of 6-1 was as high as 1300 ° C., a phosphor with high crystallinity was produced and there was little amorphous, the production of the fibrous body 5a was not observed.

On the other hand, sample no. In 6-2 to 6-6, the fibrous body 5a was present on the surface of the phosphor core, and no whitening of the wavelength converter was confirmed even when the temperature cycle was 800 cycles.
(Light emitting device)
The light emitting device 11 of FIG. 1 was produced. An alumina substrate was used as the substrate (base) 15, a light emitting element in which a nitride semiconductor was epi-formed on a sapphire substrate was used as the light emitting element 17 provided on the substrate 15, and aluminum (Al) was used as the reflecting member 21.

  First, a wavelength converter was produced. This wavelength converter has a sample No. shown in Table 10 in 2.4 g of the material constituting the transparent matrix (silicone resin: Shin-Etsu Chemical CY52-205). A phosphor paste was prepared by adding 0.101 g of a red light-emitting phosphor, 0.058 g of a green light-emitting phosphor, and 0.441 g of a blue light-emitting phosphor and mixing with a stirring deaerator.

  This paste was sandwiched between two glass substrates, heated at 150 ° C. for 30 seconds, and the silicone resin was solidified to a thickness of 0.7 mm. The average particle diameter of the phosphor was controlled by the mesh diameter through which the produced phosphor powder passed.

  The obtained light-emitting device was measured for luminous efficiency using a total luminous flux measuring device LABSPHERE. The results are shown in Table 10.

  Sample No. in Table 10 7-2, no. 7-3, no. As can be seen from 7-4, the luminous efficiency increases as the difference in the average particle size of the red-emitting phosphor and the green-emitting phosphor and the blue-emitting phosphor increases. This is because the larger the difference in average particle size between the red and green light emitting phosphors and the blue light emitting phosphor, the more the quantum efficiency of the red and green light emitting phosphors is affected by the diffuse reflection in the blue light emitting phosphor. This is thought to be due to the improvement.

It is a schematic sectional drawing which shows the structure of a light-emitting device. It is a graph which shows the result of having measured fluorescent substance by powder X-ray diffraction. M to ¹ ₃ MgSi ₂ O ₈ crystal grains is a SEM photograph showing the structure there are ^M 1 MgSiO ₄ crystal grains. It is a figure which shows the L3 absorption edge XANES spectrum result of fluorescent substance. It is a SEM photograph explaining the fluorescent substance particle which has a fluorescent substance core and a fibrous body. It is a schematic diagram for demonstrating the fibrous body of FIG. It is a TEM photograph of the mixed powder before reduction. It is an X-ray-diffraction measurement result after an oxidation process. (A) shows the sample No. in Table 1. 1-2 is an X-ray diffraction diagram of 1-2, (b) is a sample No. of Table 1. It is a 1-7 X-ray-diffraction figure. It is a graph which shows the relationship between peak intensity ratio D / (A + B + C + D) and red quantum efficiency. It is a figure which shows the measurement result by XANES of fluorescent substance.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Light-emitting device 13 ... Electrode 15 ... Board | substrate 17 ... Light emitting element 19 ... Wavelength converter

Claims (4)

  A wavelength converter that converts the wavelength of light emitted from a light source and outputs output light including the wavelength-converted light, the phosphor that emits red light and the phosphor that emits blue light in a transparent matrix And phosphors emitting green light are dispersed, and the quantum efficiency of the phosphor emitting blue light is higher than the quantum efficiency of the phosphor emitting red light and the phosphor emitting green light, and The wavelength converter, wherein an average particle diameter of the phosphor emitting blue light is smaller than an average particle diameter of the phosphor emitting red light and the phosphor emitting green light.   The average particle diameter of the phosphor emitting blue light is 10 μm or less, and the average particle diameter of the phosphor emitting red light and the phosphor emitting green light is 15 μm or more. Wavelength converter.   A light-emitting device comprising: a light-emitting element; a base on which the light-emitting element is mounted; and a wavelength converter according to claim 1 that converts the wavelength of light emitted from the light-emitting element.   A lighting device comprising a plurality of the light-emitting devices according to claim 3.