JP4890017B2 - Blue light emitting phosphor and light emitting module using the same - Google Patents

Description

  The present invention relates to a blue light-emitting phosphor and a light-emitting module using the same, and more particularly, to a blue light-emitting phosphor having higher light emission efficiency than the conventional one and a high-luminance light-emitting module using the same.

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 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 technique for mixing red three-component phosphors is introduced. Examples of the blue light emitting phosphor used in this case include those described in Patent Document 2 and Patent Document 3, and the like. BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , Sr ₅ (PO ₄ ) ₃ Cl: Eu ^{2 A} typical example is ⁺ .

  However, phosphors emitting red and green light that have absorption in a broad band have a problem in that they absorb blue light, blue light emission becomes unstable, and stable white light cannot be obtained.

Japanese Patent No. 2927279 JP 2003-160785 A Japanese Patent Laid-Open No. 2004-127988

  An object of the present invention is to solve the above-mentioned problems and to provide a blue-emitting phosphor having improved emission intensity. Moreover, a high-intensity white LED light-emitting module can be manufactured by using the blue light-emitting phosphor with improved light emission intensity obtained in the present invention.

  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) A blue light-emitting phosphor represented by the following general formula.
_{Ca 5-X-Y Mg X} (PO 4) 3 Cl: Eu 2+ Y
(0.5 ≦ X ≦ 2.5, 0 <Y, and 0.5 <X + Y <5)
(2) The blue light-emitting phosphor according to (1), wherein the excitation peak wavelength is 390 to 410 nm.
(3) A light emitting module comprising at least a semiconductor light emitting element having an emission peak wavelength of 390 to 410 nm and the blue light emitting phosphor described in (1) or (2).
(4) The light emitting module according to (3), wherein a phosphor that emits another color is used as a constituent.
(5) The light emitting module according to (4), wherein the phosphors emitting other colors are at least a red light emitting phosphor and a green light emitting phosphor and emit white light.

According to the present invention, Sr ₅ (PO ₄ ) Cl: Eu ²⁺ , which is one of the existing blue light-emitting phosphors, is replaced with Ca, the Mg element is present, and the ratio of Ca, Mg and Eu is changed. By adjusting, it is possible to provide a blue light-emitting phosphor having improved emission intensity as compared with the conventional one.

The blue phosphor of the present invention has a light emission intensity higher than that of the blue light-emitting phosphor BaMgAl ₁₀ O ₁₇ : Eu used in the three-wavelength white light-emitting LED using near ultraviolet to short-wavelength visible light (350 to 420 nm) as an excitation light source. By using the blue light-emitting phosphor of the present invention, the luminous efficiency of the white LED is expected to be improved.

  The blue light-emitting phosphor of the present invention is represented by the following general formula.

_{Ca 5-X-Y Mg X} (PO 4) 3 Cl: Eu 2+ Y

(0.5 ≦ X ≦ 2.5, 0 <Y, and 0.5 <X + Y <5)

  Such a blue light-emitting phosphor represented by the above general formula has an excitation peak wavelength of 350 to 420 nm, and among them, the excitation peak wavelength is preferably 390 to 410 nm. In the above general formula, it is preferable that Y ≦ 0.5.

Moreover, the blue light emitting phosphor of the present invention can be combined with an ultraviolet light emitting semiconductor element to form a light emitting module. For example, a white light emitting module can be obtained by combining an ultraviolet light emitting semiconductor element and a red / green light emitting phosphor.
In this case, the white light emitting module basically uses a red light emitting phosphor and a green light emitting phosphor in addition to the blue 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 red light-emitting phosphor (R), the green light-emitting phosphor (G), and the blue light-emitting phosphor (B) of the present invention are used as the phosphor, their blending ratio (mass) (R) 35-75: (G) 15-50: (B) 2-30, more preferably (R) 45-74: (G) 20-45: (B) 5-15.
Although it does not specifically limit as fluorescent substance other than the blue light emission fluorescent substance of this invention, A well-known publicly used fluorescent substance can also be used suitably.

In addition, a publicly known and commonly used blue light-emitting phosphor can also be used in combination with the blue light-emitting phosphor of the present invention.
Examples of the publicly known phosphor include those described in the background art of this specification.
The phosphor other than the blue light-emitting phosphor that can be used in combination with the present invention, which is essential for the light-emitting module, and the publicly known blue light-emitting phosphor are preferably UV-resistant.

The semiconductor light-emitting device used in the light-emitting module using the blue light-emitting phosphor of the present invention is not particularly limited as long as the emission peak wavelength is 350 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 350 to 420 nm.

A light emitting module using the blue light emitting phosphor of the present invention is composed of the semiconductor light emitting element and the phosphor containing the blue light emitting fluorescence of the present invention. More specifically, on the semiconductor light emitting element. And a structure in which the phosphor layer is provided.
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 a light emitting module using the blue light emitting phosphor of the present invention is shown in FIG. In the light emitting module shown in FIG. 4, one chip is a short wavelength visible light LED chip having an InGaN active layer and a center wavelength of about 395 nm. This 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 blue light emitting phosphor of the present invention has a predetermined whiteness, and is preferably in accordance with the following numerical prescription range which is the white prescription of the vehicle lamp of JIS D 5500. In the chromaticity diagram, this corresponds to the shaded portion in FIG.

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 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]
_{Ca 5-X-Y Mg X} (PO 4) 3 Cl: Preparation of _{Eu 2+ Y (X = 1.5,} Y = 0.1)
CaCO ₃ , MgCO ₃ , Eu ₂ O ₃ , CaCl ₂ and (NH ₄ ) H ₂ (PO ₄ ) were weighed in a molar ratio of 2.9: 1.5: 0.05: 0.5: 3.0, and after homogeneous mixing, 800-800 in an alumina crucible. Firing was performed at 1000 ° C. for 3 hours. Thereafter, the fired product is pulverized in a mortar, and after the pulverized product and (NH ₄ ) Cl are mixed in a mortar, the alumina crucible with a lid is 900 to 1100 ° C. in an N ₂ atmosphere containing ₂ to 5% H ₂ . The phosphor was synthesized by firing for 3 hours.

[Example 2]
_{Ca 5-X-Y Mg X} (PO 4) 3 Cl: Preparation of _{Eu 2+ Y (X = 1.0,} Y = 0.1)
Except that CaCO ₃ , MgCO ₃ , Eu ₂ O ₃ , CaCl ₂ and (NH ₄ ) H ₂ (PO ₄ ) were weighed in a molar ratio of 3.4: 1.0: 0.05: 0.5: 3.0, the same method as in Example 1 was used. A phosphor was synthesized.

Example 3
_{Ca 5-X-Y Mg X} (PO 4) 3 Cl: Preparation of _{Eu 2+ Y (X = 0.5,} Y = 0.1)
Except that CaCO ₃ , MgCO ₃ , Eu ₂ O ₃ , CaCl ₂ and (NH ₄ ) H ₂ (PO ₄ ) were weighed in a molar ratio of 3.9: 0.5: 0.05: 0.5: 3.0, the same method as in Example 1 was used. A phosphor was synthesized.

Example 4
_{Ca 5-X-Y Mg X} (PO 4) 3 Cl: Preparation of _{Eu 2+ Y (X = 2.5,} Y = 0.1)
Except that CaCO ₃ , MgCO ₃ , Eu ₂ O ₃ , CaCl ₂ and (NH ₄ ) H ₂ (PO ₄ ) were measured at a molar ratio of 1.9: 2.5: 0.05: 0.5: 3.0, the same method as in Example 1 was used. A phosphor was synthesized.

[Comparative Example 1]
With respect to BaMgAl ₁₀ O ₁₇ : Eu (trade name: LP-B4, manufactured by Kasei Optonics Co., Ltd.) which is a blue light emitting phosphor, an excitation spectrum and an emission spectrum were measured, and an integrated emission intensity was calculated.

[Comparative Example 2]
With respect to Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu (trade name: LP-B3, manufactured by Kasei Optonics Co., Ltd.) which is a blue light emitting phosphor, an excitation spectrum and an emission spectrum were measured, and an emission integrated intensity was calculated.

[Comparative Example 3]
_{Ca 5-X-Y Mg X} (PO 4) 3 Cl: Preparation of _{Eu 2+ Y (X = 0.3,} Y = 0.1)
Except that CaCO ₃ , MgCO ₃ , Eu ₂ O ₃ , CaCl ₂ and (NH ₄ ) H ₂ (PO ₄ ) were weighed in a molar ratio of 4.1: 0.3: 0.05: 0.5: 3.0, the same method as in Example 1 was used. A phosphor was synthesized.

[Comparative Example 4]
_{Ca 5-X-Y Mg X} (PO 4) 3 Cl: Preparation of _{Eu 2+ Y (X = 3.0,} Y = 0.1)
Except that CaCO ₃ , MgCO ₃ , Eu ₂ O ₃ , CaCl ₂ and (NH ₄ ) H ₂ (PO ₄ ) were weighed in a molar ratio of 1.4: 3.0: 0.05: 0.5: 3.0, the same method as in Example 1 was used. A phosphor was synthesized.

  For the phosphors obtained in the examples and comparative examples, the excitation spectrum and emission spectrum were measured, and the emission integrated intensity was calculated.

[Excitation spectrum]
The excitation spectrum distribution shown in FIG. 1 was obtained.
In the excitation spectrum of BaMgAl ₁₀ O ₁₇ : Eu (Comparative Example 1), the emission efficiency decreases as the wavelength increases in the wavelength range of 360 nm or more of the peak wavelength. However, the phosphor of the present invention (Example 2) has a peak at 400 nm, and the InGaN / GaN-based semiconductor device emits light strongly in a wavelength range of 390 to 410 nm showing the maximum external quantum efficiency. Further, the emission intensity is higher than that of (Sr, Ca, Ba) ₅ (PO ₄ ) ₃ Cl: Eu (Comparative Example 2) having an excitation peak at 400 nm (FIG. 1).

[Emission spectrum]
FIG. 2 shows the emission spectrum distribution. The emission peak wavelength of the phosphor of the present invention (Example 2) is 460 nm, which is a broad emission spectrum with respect to BaMgAl ₁₀ O ₁₇ : Eu, which is an emission spectrum with an emission peak wavelength of 450 nm. In addition, when excited by light of 400 nm from a semiconductor element, the phosphor of the present invention obtained a light emission intensity 1.8 times that of Comparative Example 1 and 1.5 times that of Comparative Example 2 (FIG. 2).

  Table 1 shows the composition, emission peak wavelength, excitation peak wavelength, and emission intensity of the example phosphors. In Comparative Example 4, it was impossible to measure the light emission characteristics because the phosphor was vitrified.

  Since the emission spectra and excitation spectra of Examples 1 to 4 showed substantially the same shape, FIG. 1 shows Example 2 and the comparative example with the highest emission intensity, and Examples 1, 3 and 4 were omitted. .

  FIG. 3 shows the relationship between the amount of magnesium X and the integrated emission intensity when the integrated emission intensity of the phosphor of Comparative Example 1 at 400 nm is 1. From FIG. 3, the maximum value of the emission intensity is obtained in the range of 1.0 <X <1.5. Further, it was revealed that the emission intensity was higher than that of Comparative Example 1 in the range of 0.5 ≦ X ≦ 2.5.

Production of Light Emitting Module As a semiconductor light emitting device, an InGaN / GaN LED chip having an emission wavelength of 395 nm and an external quantum efficiency of 18% is used as a red light emitting phosphor, and La ₂ O ₂ S: Eu ³⁺ is used as a green light emitting phosphor. The phosphor of Example 1 was used as BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ²⁺ as a blue light-emitting phosphor.
In order to study the light emission characteristics of the region surrounded by AGDC in FIG. 6, which is a desired chromaticity range for vehicle lighting, using the LED chip and each color light emitting phosphor, the F coordinate (x , Y = 0.36, 0.365).

  Specifically, each of the above-described light emitting phosphors (red, green, and blue) was mixed with a ball mill at a spectral fraction ratio of 70: 25: 5 to prepare a mixed phosphor. The mixed phosphor and a silicone resin (JCR-6125 manufactured by Toray Dow Corning Silicone Co., Ltd.) were mixed at 1: 1 to prepare a phosphor paste. The phosphor paste was potted to cover the LED chip fixed in a lead frame shaped like a cup and cured at 150 ° C. for 1 hour to immobilize the mixed phosphor on the LED chip.

Light Emitting of Light-Emitting Module The produced light-emitting module was made to emit light by energizing the LED chip with a driving current of 20 mA and a driving voltage of 3.5 V.

  Table 2 shows a comparison of the total luminous flux when the light emitting module is used. In Example 1, the total luminous flux was larger than those of Comparative Examples 1 and 2.

  The blue light emitting phosphor of the present invention can be combined with, for example, an ultraviolet light emitting semiconductor element to constitute a light emitting module, and the light emitting module can be expected to be applied to, for example, a vehicle lamp.

It is a figure showing the excitation spectrum distribution of the blue light emission fluorescent substance of Example 2 and Comparative Examples 1-3. It is a figure showing the emission spectrum distribution of the blue light emission fluorescent substance of Example 2 and Comparative Examples 1-3. It is a figure showing the relationship between the amount of magnesium and the emitted light intensity of a blue light emission fluorescent substance. It is a figure which shows one example of the form of the light emitting module using the blue light emission fluorescent substance of this invention. It is a chromaticity diagram which shows the preferable range of the whiteness of the light which the white light emitting module using the blue light emission fluorescent substance of this invention light-emits. It is a chromaticity diagram which shows the more preferable range of the whiteness of the light which the white light emitting module using the blue light emission fluorescent substance of this invention light-emits.

Explanation of symbols

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

Claims (5)

A blue light-emitting phosphor represented by the following general formula:
_{Ca 5-X-Y Mg X} (PO 4) 3 Cl: Eu 2+ Y
( 1.0 < X <1.5 , 0 <Y, and 0.5 <X + Y <5)   The blue light-emitting phosphor according to claim 1, wherein an excitation peak wavelength is 390 to 410 nm.   A light emitting module comprising at least a semiconductor light emitting element having an emission peak wavelength of 390 to 410 nm and the blue light emitting phosphor according to claim 1.   4. The light emitting module according to claim 3, wherein phosphors emitting other colors are used as constituents. 5. The light emitting module according to claim 4, wherein the phosphors emitting other colors are at least a red light emitting phosphor and a green light emitting phosphor and emit white light.

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