JP5063938B2 - Orange phosphor - Google Patents

Description

  The present invention relates to an orange light-emitting phosphor, and more specifically, an orange light-emitting phosphor that has high luminance and excellent color rendering when used in a white light-emitting module instead of a conventional red light-emitting phosphor. About.

In light of environmental issues and power savings, light source diodes (LEDs) and semiconductor lasers (LDs) that do not use mercury are combined with phosphors as excitation light sources, and light sources at that time are used as light sources. Has been.
For example, Patent Document 1 exhibits white light emission as a whole by additive mixing with yellow light emission from a Ce-activated rare earth aluminate phosphor that emits light by absorbing part of blue light emission. A light emitting diode is disclosed. However, this type of combination has a problem in color rendering properties because the emission color of white light finally obtained is limited, and color reproducibility under illumination of this light source is not reproduced in a preferable color. In addition, there is a problem in that the ratio of the blue light and the yellow light is not stable due to the variation in the amount of phosphors installed on the optical path of light emitted from the light emitting diode, and the light emission color of the light emitting module is not stable.
In recent years, in order to solve such problems, as a method for compensating for the disadvantages of white synthesis by adding two colors, ultraviolet or short-wavelength visible light is used as primary light (excitation light) from a semiconductor light emitting device, and green, blue, A light emitting module by mixing phosphors of three red components (additive color mixture) has been introduced (see, for example, Patent Document 2). Here, BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , (Sr, Ca, Ba) ₅ (PO ₄ ) ₃ Cl: Eu ^2+, etc., are used as blue light emitting phosphors, and Ca ₈ Mg (SiO ₄ ) ₄ is used as a green light emitting phosphor. Cl: Eu ²⁺ , Mn ²⁺ , BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ^2+, etc. As red-emitting phosphors, Y ₂ O ₂ S: Eu ²⁺ (YOS: Eu), Y ₂ O ₃ : Eu, Bi, La ₂ O ₂ S: Eu ³⁺ (LOS: Eu) and the like.

  However, among the phosphors that emit red, green, and blue colors, the red light-emitting phosphor has lower luminous efficiency than the phosphor that emits each color of green and blue, so that a desired white color (for example, chromaticity x / In order to obtain y = 0.36 / 0.365), the red light emitting phosphor must be mixed in a larger proportion than the phosphor emitting green and blue colors, for example, the mixing ratio should be close to 90%. did not become. For this reason, the compounding ratio of the green / blue light-emitting phosphors having good luminous efficiency is low, and a light emitting module that emits white with high luminance cannot be obtained.

Among the conventional red light-emitting phosphors, LOS: Eu (hereinafter also referred to as LOS) was developed in the “21st Century Light” project and is currently the most excellent red light-emitting phosphor, and is also regarded as a standard product of red light-emitting phosphors. ing.
However, the excitation peak wavelength is 340 nm, which is far from the maximum output wavelength (400 nm) of the ultraviolet LED chip, and it has been a problem that light emission with sufficiently satisfactory brightness cannot be obtained with the excitation light of 400 nm. .

  Further, the emission spectrum of LOS has a sharp emission peak at 624 nm, and a white light emitting module using additive color mixture using such a red light emitting phosphor cannot obtain sufficient color rendering.

Japanese Patent No. 2927279 Japanese Patent Laid-Open No. 2004-127988

  Accordingly, an object of the present invention is to solve the above-described problems, and to provide high luminance and excellent color rendering when used in a white light emitting module instead of a conventional red light emitting phosphor. It is to provide a light-emitting phosphor that can be used.

  As a result of intensive studies, the present inventors have achieved the above object by adopting the following configuration, and have achieved the present invention.

(1) An orange light-emitting phosphor having a Ca pyrophosphate crystal structure and represented by the following general formula.
_{Ca 2-XYZ M X P 2} O 7: Eu Y, Mn Z
(In the formula, M represents an alkaline earth element other than Ca, and X ≧ 0, Y> 0, and Z> 0.)
(2) The orange light-emitting phosphor according to (1), wherein the Ca pyrophosphate crystal structure is α-type.
(3) The orange-emitting phosphor according to (1) or (2), wherein 0.1 ≦ Y + Z ≦ 0.6 in the general formula.
(4) The orange-emitting phosphor according to any one of (1) to (3), wherein 0.15 ≦ Y + Z ≦ 0.45 in the general formula.
(5) The orange-emitting phosphor according to any one of (1) to (4), wherein 0.2 ≦ Z / Y + Z ≦ 0.8 in the general formula.
(6) The orange light-emitting phosphor according to any one of (1) to (5), wherein the excitation peak wavelength is 350 to 420 nm.

The orange-emitting phosphor of the present invention has (1) the peak wavelength of the excitation spectrum is in the vicinity of 400 nm, which is the maximum output wavelength region of the ultraviolet LED chip, and (2) the emission peak wavelength is 600 nm, which is higher in visibility than red, (3) Since the light emission (integration) intensity is larger than that of the conventional LOS, when used in a white light-emitting module, a high-luminance product can be obtained.
Moreover, since the orange light-emitting body of this invention (4) has a broad emission spectrum, when it was used for the white light-emitting module, it became excellent in color rendering.

  The orange-emitting phosphor of the present invention has higher luminous efficiency, better visibility and luminance than conventional red-emitting phosphors, and when used in a white light-emitting module, it emits white light with high efficiency and excellent luminance and color rendering. It can be a module.

  The orange light-emitting phosphor of the present invention has a Ca pyrophosphate crystal structure and is represented by the following general formula.

_{Ca 2-XYZ M X P 2} O 7: Eu Y, Mn Z
(In the formula, M represents an alkaline earth element other than Ca, and X ≧ 0, Y> 0, and Z> 0.)

Such an orange light emitting phosphor represented by the above general formula has an excitation peak wavelength of 350 to 420 nm.
In the orange light emitting phosphor represented by the above general formula, the sum Y + Z of the activator metals europium (Eu) and manganese (Mn) is not particularly limited, but is preferably 0.1 to 0.6, 0 More preferably, it is 15 to 0.45.
Moreover, in the orange light-emitting phosphor represented by the above general formula, the ratio of Mn Z / Y + Z in the total activator (Eu + Mn) is not particularly limited, but is preferably 0.2 to 0.8.

  The orange light-emitting phosphor of the present invention is not particularly limited, but preferably has a particle size of 50 μm or less. When the particle size is 50 μm or less, scattering of light on the particle surface of the phosphor can be prevented, and the phosphor can emit light efficiently.

The orange light-emitting phosphor of the present invention can be combined with an ultraviolet semiconductor light-emitting element to form a light-emitting module.
Furthermore, phosphors emitting other colors can be used as constituents. For example, a white light emitting module can be obtained by combining an ultraviolet light emitting semiconductor element and a blue / green light emitting phosphor.
In this case, the white light emitting module basically uses a blue light emitting phosphor and a green light emitting phosphor in addition to the orange light emitting phosphor of the present invention. In order to obtain it, it is also possible to use other phosphors.

  On the other hand, when only the orange light-emitting phosphor (O), the green light-emitting phosphor (G), and the blue light-emitting phosphor (B) of the present invention are used as the phosphor, the blending ratio thereof is a spectral fraction ratio. , (O) 35-75: (G) 15-50: (B) 2-30, more preferably (O) 45-74: (G) 20-45: (B) 5 15.

The green phosphor and the blue phosphor other than the orange light emitting phosphor of the present invention are not particularly limited, and publicly known phosphors can also be used as appropriate.
In addition, in combination with the orange light-emitting phosphor of the present invention, conventionally publicly known red light-emitting phosphors and orange light-emitting phosphors can be used as appropriate.
Examples of the publicly known phosphor include those described in the background art of this specification.
And, the orange light emitting phosphor of the present invention, which is essential for the light emitting module, and the blue light emitting phosphor, the green light emitting phosphor, the publicly known red light emitting phosphor, and the orange light emitting phosphor that can be used in combination are UV resistant. Is preferred.

The semiconductor light-emitting device used in the light-emitting module using the orange light-emitting phosphor of the present invention is not particularly limited as long as the emission peak wavelength is 360 to 420 nm. InGaN / GaN generally used as a semiconductor light-emitting device that emits ultraviolet light. The system type is preferred. Specifically, those described in JP-A-2002-17100 can be suitably used.
In an InGaN / GaN-based semiconductor light emitting device, the emission peak wavelength becomes longer as the In amount increases, and the emission peak wavelength becomes shorter as the In amount decreases. Therefore, in order to apply the InGaN / GaN-based semiconductor light emitting device to the light emitting module, the amount of In is adjusted as appropriate so that the emission peak wavelength becomes 360 to 420 nm.

A light emitting module using the orange light emitting phosphor of the present invention is composed of the above semiconductor light emitting element and a phosphor containing the orange light emitting phosphor of the present invention, and more specifically, the semiconductor light emitting element. The structure which provides the layer of this fluorescent substance on is mentioned.
In that case, the phosphor layer provided on the semiconductor light emitting element may be a single layer or a plurality of layers in which at least one kind of phosphor is laminated and a plurality of phosphors are arranged in a single layer. You may mix and arrange | position. As a form in which the phosphor layer is provided on the semiconductor light emitting element, a form in which the phosphor is mixed with a coating member that covers the surface of the semiconductor light emitting element, a form in which the phosphor is mixed with the mold member, or a covering that covers the mold member And a mode in which a translucent plate in which the phosphor is mixed is disposed in front of the light emitting side of the semiconductor light emitting element lamp.

  In addition, at least one of the aforementioned phosphors may be added to the mold member on the semiconductor light emitting device. Furthermore, you may provide the fluorescent substance layer which consists of at least 1 sort (s) or more of the above-mentioned fluorescent substance on the outer side of a light emitting module. As a form provided on the outside of the light emitting module, a form in which the phosphor is applied in layers on the outer surface of the mold member of the light emitting module, or a molded body in which the phosphor is dispersed in rubber, resin, elastomer or the like (for example, cap shape) The form which coats this to a semiconductor light emitting element, or the form which processes the above-mentioned fabrication object in the shape of a plate, and arranges this in front of a semiconductor light emitting element, etc. are mentioned.

An example of a specific form of the light emitting module using the orange light emitting phosphor of the present invention is shown in FIG. In the light emitting module shown in FIG. 7, one chip is a short wavelength visible light LED chip having an InGaN active layer and a center wavelength of around 395 nm. The short wavelength visible light LED chip 1 is connected to a lead frame 2 via an adhesive layer. It is fixed to. The short wavelength visible light LED chip 1 and the lead frame 2 are electrically connected by a gold wire 3. The short wavelength visible light LED chip 1 is covered with a phosphor paste 4 in which a phosphor powder is kneaded with a binder resin. Examples of the binder resin of the phosphor paste 4 include silicone resin, epoxy resin, urethane resin, norbornene resin, fluorine resin, metal alkoxide, polysilazane, and acrylic resin. In addition, the light emitting module has a sealing material 5 that covers the periphery of the phosphor paste 4. Examples of the sealing material 5 include materials that are transparent to visible light, such as silicone resin, epoxy resin, urethane resin, norbornene resin, fluorine resin, acrylic resin, and low-melting glass.
In addition, the form for light emitting modules is not limited to this light emitting module structure, For example, there exist various forms, such as coating the light emission surface of the short wavelength visible light LED chip 1 as a fluorescent substance layer.

  The white light-emitting module using the orange light-emitting phosphor of the present invention preferably has a predetermined whiteness. Specifically, the white light-emitting module according to JIS D 5500 defines the white color of the vehicle lamp as follows. If it is shown by a chromaticity diagram, the one corresponding to the shaded portion in FIG. 8 is preferable.

Yellow direction x ≦ 0.50
Blue direction x ≧ 0.31
Green direction y ≦ 0.44 and y ≦ 0.15 + 0.64x
Purple direction y ≧ 0.05 + 0.75x and y ≧ 0.382

  A more preferable whiteness defining range is as follows, and if shown in the chromaticity diagram, it corresponds to the shaded portion of FIG.

  0.310 ≦ x ≦ 0.405 and blackbody radiation locus ≦ y ≦ 0.15 + 0.64x

The color rendering properties of the white light emitting module using the orange light emitting phosphor of the present invention will be described.
The color rendering property is an index indicating how close the color of the reflected light obtained by applying the measurement light to the sample is with respect to the actual color of the sample. As for the numerical value, the maximum value is 100, and the larger the value, the higher the color rendering properties (good). Specifically, how close is the color of the reflected light obtained by applying the measurement light to the sample (100 is MAX) with respect to the actual color of the sample (the color when ideal white light is applied). Values are measured for various samples (regular colors), and the average of the values is Ra.
The color rendering property of the white light emitting module using the orange light emitting phosphor of the present invention is preferably closer to 100, but is not particularly limited, and is desirably 60 or more.

The present invention will be described more specifically with reference to the following examples. However, the scope of the present invention is not limited to these examples.
[Example 1]
Preparation of Phosphor A predetermined amount of phosphor powder material was weighed in a stoichiometric ratio, mixed in a mortar, placed in a crucible, baked and ground to obtain the target phosphor.
Table 1 shows phosphor materials used and firing conditions.

Table 2 shows the composition of the Ca pyrophosphate phosphor obtained by the solid phase method.
Ca pyrophosphate phosphor structural formula: (Ca, Mg, Eu, Mn) ₂ P ₂ O ₇
Eu = 0.1 mol, Mn = 0.2 mol constant

The emission spectrum of the obtained Ca pyrophosphate phosphor of Example 1 at 400 nm excitation is shown in FIG. 1, and the excitation spectrum is shown in FIG.
As shown in FIG. 1, an orange-emitting phosphor having a peak near 600 nm and a broad excitation spectrum in the near ultraviolet region as shown in FIG. 2 was obtained.
The smaller the amount of Mg added, the larger the integrated emission intensity and the longer the peak wavelength, and the peak wavelength was changed from 606 nm to 623 nm. The integrated emission intensity at 400 nm excitation without Mg addition was 2.1 times that of LOS, and it was found to be promising as a phosphor for near ultraviolet excitation LED.

[Example 2]
Confirmation of Crystallinity XRD measurement of CPH43 (Mg = 0 mol), which had the maximum emission intensity in Example 1, was performed to confirm the crystallinity having an α-type crystal structure. The results are shown in FIG.
Ca ₂ P ₂ O ₇ (Ca pyrophosphate) was confirmed as the main component layer, and Ca ₁₉ Mn ₂ (PO ₄ ) ₁₄ (FIG. 3 ↓ marked portion) was confirmed as the subcomponent layer. It has been found that by reducing the amount of Mn introduced, the subcomponent layer can be reduced and can be brought closer to a Ca ₂ P ₂ O ₇ single phase.

[Example 3]
Examination of amount of activator Eu and Mn activators were optimized in order to investigate the possibility of further improvement of light emission characteristics with Eu ²⁺ and Mn ²⁺ activated Ca pyrophosphate.
(1) Relationship between the total amount of activator and emission intensity In order to see the relationship between the total amount of activator (Eu + Mn) and emission intensity, the Eu / Mn ratio = 1/2 constant and the prototype shown in Table 3 based on CPH43. I did it. The results are shown in FIG. As a result, it was found that the luminous intensity became maximum when the total amount of activator (Eu + Mn) was 0.3 mol.

(2) Relationship between Mn concentration in total amount of activator and emission intensity at 400 nm excitation In order to see the relationship between Mn concentration in the activator and emission intensity at 400 nm excitation, Eu + Mn = 0.3 mol constant, The prototype shown in Table 4 was made. The results are shown in FIG.
As a result, it has been found that when the Mn concentration in the activator is 5% to 90%, the emission intensity is greater than the LOS and is maximum in the range of 33 to 50%.

[Example 4]
White blend simulation evaluation of Ca pyrophosphate orange light emitting phosphors Eu ²⁺ , Mn ²⁺ Activated Ca pyrophosphate is mixed with green and blue light emitting phosphors, and the phosphor mixture ratio (spectrum component) when whitened Rate ratio) and light emission characteristics were confirmed by simulation evaluation. Table 5 shows blend combinations, and Table 6 shows phosphor blending ratios and light emission characteristics. Further, FIG. 6 shows an emission spectrum of a phosphor that is white-blended to the target chromaticity (cx = 0.360, cy = 0.365).

By using Eu ²⁺ and Mn ²⁺ activated Ca pyrophosphate as the red component in the examples, the total luminous flux ratio is 1.6 times that of the comparative example, and the average color rendering index (hereinafter referred to as Ra) is improved by 36 points. It was confirmed that Ra72 was obtained. This is considered to be because the emission spectrum of 550 to 700 nm rises because the emission spectrum is broader than LOS in the red part.

2 is a graph showing an emission spectrum distribution of Eu ²⁺ and Mn ²⁺ activated Ca pyrophosphate in Example 1. FIG. 2 is a diagram illustrating an excitation spectrum distribution of Eu ²⁺ and Mn ²⁺ activated Ca pyrophosphate in Example 1. FIG. 4 is a diagram illustrating an XRD pattern of an orange light emitting phosphor of Example 2. FIG. FIG. 5 is a diagram illustrating the relationship between the amount of activator of the orange light-emitting phosphor of Example 3 and light emission intensity. It is a figure showing the relationship between the Mn density | concentration in the activator total amount of the orange light emission fluorescent substance of Example 3, and the emitted light intensity by 400 nm excitation. 6 is a diagram illustrating an emission spectrum of white blend simulation in Example 4. FIG. It is a figure which shows one example of the form of the white light emitting module using the orange light emission fluorescent substance of this invention. It is a chromaticity diagram showing a preferred range of whiteness of light emitted from a white light emitting module using the orange light emitting phosphor of the present invention. It is a chromaticity diagram showing a more preferable range of whiteness of light emitted from a white light emitting module using the orange light emitting phosphor of the present invention.

Explanation of symbols

1 LED chip 2 Lead frame 3 Metal wire 4 Phosphor paste 5 Sealing material

Claims (3)

An orange light emitting phosphor having a Ca pyrophosphate crystal structure and represented by the following general formula.
_{Ca 2-X-Y-Z} M X P 2 O 7: Eu Y, Mn Z
( Wherein , M represents an alkaline earth element other than Ca, 0 ≦ X ≦ 0.2 , Y> 0, Z> 0, 0.15 ≦ Y + Z ≦ 0.45, 0.33 ≦ Z / Y + Z ≦ 0.5 .) 2. The orange-emitting phosphor according to claim 1, wherein the Ca pyrophosphate crystal structure is α-type . 3. The orange light emitting phosphor according to claim 1, wherein the excitation peak wavelength is 350 to 420 nm.

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