JP2004111344A - Light emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device with an excellent color rendering property and color reproduction as a multicolor or white color light source saving power consumption and replacing a fluorescent lamp, without using a harmful substance such as mercury as a component. <P>SOLUTION: The light emitting device is provided with a light source for excitation with a peak wavelength of a emission spectrum in a near-ultraviolet or short wavelength visible range, and a red light emitting phosphor with a composition (M<SB>1-x</SB>M'x)O-n(Al<SB>1-y</SB>Ga<SB>y</SB>)<SB>2</SB>0<SB>3</SB>:Mn<SB>z</SB>(M=Ca, Sr, M'= Ba, Mg, Zn, O≤x≤0.1, 0≤y≤0.1, 1x10<SP>-4</SP>≤z≤1x10<SP>-1</SP>(g.atm/matrix 1 mol), 2≤n≤8), or a compound phosphor formed of the red light emitting phosphor and other color light emitting phosphor in a position where light emitted from the light source for excitation can be absorbed, and emits light with a different peak wavelength. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light emitting device used for illumination or display, which emits light of various emission colors by a combination of a light source for excitation that emits light in the near ultraviolet or short wavelength visible region and a phosphor.
[0002]
[Prior art]
A fluorescent lamp is known as one of typical uses of the phosphor, and has been used for a long time as a lighting or a display. As is well known, a fluorescent lamp utilizes a fluorescent film formed of a phosphor formed on an inner wall of a glass tube, which is excited by ultraviolet rays generated by electric discharge in a glass tube filled with mercury vapor to emit light. Used as a light source.
[0003]
By the way, in recent years, a light emitting diode (LED) or a semiconductor laser (LD) has been used as a light source for excitation, which does not use mercury and consumes less power, from the viewpoint of environmental problems and power saving. In addition, a method has been developed in which light is emitted from an LED or LD to excite a phosphor to emit light, and light emitted at that time is used as a light source. For example, Japanese Patent No. 2,927,279 discloses a blue activated visible light emitted by an LED chip and a Ce-activated rare earth aluminate fluorescent material that emits light by absorbing a part of the blue emitted light of the LED chip. There is disclosed a light emitting diode that emits white light as a whole by additive mixing with yellow light emitted from the body.
[0004]
However, in a conventional light source of a type in which an excitation light source such as an LED and a phosphor are combined, the emission wavelength of the excitation light source such as an LED is limited, and a phosphor which can emit light by the excitation light source used. Since the types are extremely limited, there are restrictions such as that the finally obtained luminescent color is limited to a white color or that a multi-colored color cannot be obtained. Also, with respect to white, a preferable color was not reproduced for the color under illumination, and color rendering was also a problem.
[0005]
In recent years, in order to solve such a problem, U.S. Pat. S. P. 6294800, U.S.A. S. P. No. 6,255,670 and the like, a method of mixing three components, green, blue and red, is introduced. The phosphor used here is Ca ₈ Mg (SiO ₄ ) ₄ Cl: Eu, Mn as a green light-emitting phosphor, BaMgAl ₁₀ O ₁₇ : EU as a blue light-emitting phosphor, and a red light-emitting phosphor. , Y ₂ O ₂ S: Eu or Y ₂ O ₃ : Eu, Bi, and the like.
[0006]
The method of mixing the three components has considerably improved the reproduction of the projected color under the illumination of the light source as compared with the two-color component method. However, when the color tone of each phosphor used as a component is not preferable, the color projected under the illumination of the light source is poor in reproducibility and a desired color cannot be obtained. Since the color tone is different from the desired red color, a satisfactory white light source cannot be obtained.
In recent years, not only a white light source but also a multicolor light source for illumination, display, and liquid crystal backlights have been desired to have good color reproducibility and color rendering properties.
[0007]
[Problems to be solved by the invention]
The present invention replaces fluorescent lamps with low power consumption that does not use harmful substances such as mercury as constituent elements, as a light source for displays, liquid crystal backlights, and has excellent color reproducibility, excellent color rendering, red and white and / or multicolor. It is intended to provide a light source.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present inventors have tried to emit various phosphors with various excitation light sources to excite the phosphors, so that a phosphor that can be a preferable red light source is combined with the excitation light source. Was searched in detail. As a result, the composition as a phosphor color tone _{(M 1-x M 'x} ) O · n (Al 1-y Ga y) 2 O 3: Mn z ( where M = Ca, Sr, M' = Ba, Mg, Zn, 0 ≦ x ≦ 0.1, 0 ≦ y ≦ 0.1, ¹ × 10 ⁻⁴ ≦ z ≦ ¹ × 10 ⁻¹ (g.atm / base 1 mol), 2 ≦ n ≦ 8) Red phosphor was found.
On the other hand, as a result of examining white and multicolor by mixing this phosphor with other color phosphors, it was found that the color reproducibility as multicolor was excellent, and in the case of a white light source, it was projected under the illumination. The present invention has found advantages such as good red color reproduction, and has led to the present invention.
[0009]
The light emitting device of the present invention has the following configuration.
(1) An excitation light source having a peak wavelength of an emission spectrum in a near ultraviolet or short wavelength visible region, and a light source for excitation that is disposed at a position capable of absorbing light emission from the excitation light source. A phosphor that absorbs at least a part of the phosphor and emits light having a peak wavelength different from that of the phosphor, wherein the phosphor has a composition of (M _{1−x M 'x) O · n (} Al 1-y Ga y) 2 O 3: Mn z ( where M = Ca, Sr, M' = Ba, Mg, Zn, 0 ≦ x ≦ 0.1,0 ≦ y ≦ A light-emitting device comprising an aluminate of 0.1, ¹ × 10 ⁻⁴ ≦ z ≦ ¹ × 10 ⁻¹ (g.atm / base 1 mol), 2 ≦ n ≦ 8).
[0010]
(2) an excitation light source having a peak wavelength of an emission spectrum in a near-ultraviolet or short-wavelength visible region, and an emission light source arranged at a position capable of absorbing the emission from the excitation light source. What is claimed is: 1. A light-emitting device comprising three kinds of phosphors of red, green and blue that absorb at least a part and emit light of a peak wavelength different from this, wherein the red light-emitting phosphor is (M _1−x M _{'x) O · n (Al} 1-y Ga y) 2O3: Mn z ( where M = Ca, Sr, M' = Ba, Mg, Zn, 0 ≦ x ≦ 0.1,0 ≦ y ≦ 0.1 ¹ × 10 ⁻⁴ ≦ z ≦ ¹ × 10 ⁻¹ (g.atm / base 1 mol), 2 ≦ n ≦ 8).
[0011]
(3) The light emitting device according to any one of (1) and (2), wherein a peak wavelength of an emission spectrum of the excitation light source is 300 to 500 nm.
(4) The light emitting device according to any one of (1) to (3), wherein the excitation light source is at least one of a light emitting diode (LED) and a semiconductor laser.
(5) The light emitting device according to any one of (1) to (4), wherein the excitation light source is (In, Ga) N.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The light emitting device of the present invention comprises an excitation light source such as a light emitting diode (LED) having a peak wavelength of an emission spectrum in the near ultraviolet or short wavelength visible region, and an aluminate at a position capable of absorbing the emission from the excitation light source. salts red-emitting phosphor _{(M 1-x M 'x} ) O · n (Al 1-y Ga y) 2 O 3: Mn z ( where M = Ca, Sr, M' = Ba, Mg, Zn, 0 ≦ a green light-emitting phosphor that is x ≦ 0.1, 0 ≦ y ≦ 0.1, ¹ × 10 ⁻⁴ ≦ z ≦ ¹ × 10 ⁻¹ (g.atm / base 1 mol), 2 ≦ n ≦ 8) or other color phosphor; A phosphor composed of a mixture of two or three colors mixed with a blue light-emitting phosphor is arranged, and has a configuration similar to that of a conventional light-emitting device assembled in an optically coupled form. The other color light-emitting phosphor used here is ZnS: Cu, Al, BaMgAl ₁₀ O ₁₇ : Eu, Mn, Ca ₂ MgSi ₂ O ₇ : Eu as a green light-emitting phosphor, and a blue light-emitting phosphor. BaMgAl ₁₀ O ₁₇ : Eu, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, Ca ₂ B ₅ O ₉ Cl: Eu, Sr ₂ MgSi ₂ O ₇ : Eu, (Ca, Sr , Ba) ₃ MgSi ₂ O ₈ : Eu and the like are preferably used.
[0013]
Hereinafter, the red light emitting phosphor of the present invention will be described in more detail.
The aluminate phosphor of the present invention is synthesized as follows. Examples of the phosphor raw material include: (1) one or more oxides of Ca, Sr, Ba, Zn, and Mg, which are one component of the base, or compounds thereof such as nitrates and carbonates; (2) activators Ingredients such as Mn oxides or compounds thereof such as nitrates, carbonates and chlorides, and (3) oxides of aluminum and gallium, which are constituents of the base, or nitrates, carbonates and chlorides thereof And a barogenide of an alkali metal and / or alkaline earth metal or ammonium, etc., as a flux, and thoroughly mix in a wet or dry system. The raw material is weighed in a predetermined amount, and the raw material mixture is filled in a heat-resistant container such as a crucible and fired at least once at 1000 to 1750 ° C. for 1 to 12 hours in a neutral atmosphere or an atmosphere such as air. After firing, the fired product is pulverized, washed with a thin mineral acid aqueous solution, washed with water, and further subjected to a dispersion treatment using a ball mill or the like, and then used to remove unnecessary large particles by a wet classification method such as a water sieve. After the classification treatment, drying and sieving are performed to obtain the aluminate phosphor of the present invention.
[0014]
FIG. 1 shows the emission spectrum of this red light-emitting phosphor when excited by ultraviolet light at 382 nm, which is a near-ultraviolet wavelength. The emission color is the emission of the red phosphor Y ₂ O ₂ S: Eu conventionally studied. Compared to the peak wavelength of 624 nm, it has a strong peak at 656 nm in a long wavelength region with a strong reddish color, indicating that the red color is preferable in terms of color purity.
[0015]
On the other hand, a light emitting element that emits light in the wavelength range of near ultraviolet to short wavelength visible light is used as excitation light emission, which is one of the components of the light emitting device of the present invention. The light emitting element as the excitation light source is relatively easily available, has high luminous efficiency, and can emit a phosphor with higher luminance. A light emitting diode (LED) or a semiconductor laser (LD) made of a nitride-based compound semiconductor such as (In, Ga) N, which preferably has a wavelength of 370 to 500 nm, can be used.
The light emitting device of the present invention has a positional relationship such that the phosphor can receive and absorb light from the excitation light source, and is configured to face the excitation light source.
[0016]
FIG. 3 is an example of a schematic structural view of a light emitting device of the present invention, in which a semiconductor light emitting device chip 3 is electrically bonded on a stem 1, while the other electrode of the semiconductor light emitting device chip 3 and a lead 2 are provided. Are electrically connected by a lead wire 5. A dome-shaped transparent resin-coated lid 5 is fixed to the stem 1. Then, on the inner surface of the transparent resin-coated lid 5, a binder in which a phosphor is dispersed is applied to form a phosphor layer 6. The transparent resin-coated lid 5 is made of a resin transparent to light, such as a resin such as an epoxy resin, an acrylic resin, a silicone resin, or polystyrene, or glass, and serves as a cap for hermetically sealing the semiconductor light emitting element chip 3. It is also fixed to the stem 1. When the lead wire 2 is energized, the semiconductor light emitting element chip 3 emits light, and this emitted light is applied to the surface of the phosphor layer 6 formed on the inner wall surface of the transparent resin covering lid 5 via the space layer, and the fluorescent light is emitted. The body layer 6 absorbs the light emitted from the semiconductor light-emitting element chip 3 and is excited to emit light having a light emission wavelength different from that of the semiconductor light-emitting element chip 3 and specific to the phosphor shown as a component of the present invention.
[0017]
FIG. 4 is an example of a schematic structural view showing another embodiment of the light emitting device of the present invention. In the light emitting device of this embodiment, a semiconductor light emitting element chip 13 is mounted on a header 4 and electrically connected to leads 12. Have been. Further, the semiconductor light emitting device chip 13 is covered with a transparent resin mixed with a phosphor so as to cover the semiconductor light emitting device chip 13 to form a phosphor layer 16, and the transparent resin is molded on the phosphor layer 16 to form a convex lens resin lens 15. To form Reference numeral 14 denotes a lead wire for electrically connecting the semiconductor light emitting element chip 13 and the electrode. The semiconductor light emitting element chip 13 emits light by supplying electricity through the leads 12, and the semiconductor light emitting element chip 13 absorbing the light emission is excited to emit light of a different wavelength from that of the semiconductor light emitting element chip 13. Note that the resin lens 15 and the phosphor layer 16 may be integrated, and the semiconductor light emitting element chip 13 may be molded with a transparent resin containing a phosphor dispersed therein.
Alternatively, a lead frame having a cup-shaped mount portion may be manufactured, a light emitting device chip may be arranged at the bottom, and a fluorescent material may be injected and filled into the cup-shaped mount portion together with a resin.
[0018]
Alternatively, the point light source light emitting elements illustrated in FIGS. 3 and 4 may be linearly or planarly integrated and arranged in an array to form a linear or planar light source.
By using a phosphor mixed with a red aluminate phosphor or a plurality of phosphors having different emission colors in the phosphor layer which is one component of the light emitting device of the present invention having such a structure, And a light emitting device having excellent color reproducibility and color rendition can be obtained. By realizing such a light-emitting device, it is possible to provide not only a white light source but also a multicolor light source with good color reproducibility and color rendition for illumination, display, and liquid crystal backlight, and industrially. The utility value is great.
[0019]
【Example】
Next, the present invention will be described with reference to examples, but the present invention is not limited to the embodiments exemplified in the following examples.
[Example 1]
Composition formula _CaO · _6Al 2 _{O 3:} to prepare a phosphor coating liquid by mixing an aluminate phosphor 4mg acrylic resin 1g and toluene 15g represented by _{Mn 0.001.}
Separately from this, the wafer part of the light emitting diode element which emits near-ultraviolet light having a main peak wavelength of 382 nm as an excitation light source is held horizontally, and the previously prepared phosphor coating solution is dropped on the light emitting part from a thin nozzle. After forming a dome-shaped phosphor coating film, and then half-turning the phosphor coating surface in reverse to make the phosphor coating surface horizontal and using a surface tension, the phosphor is naturally dried at room temperature in the dome-shaped coating film. After further drying at about 150 ° C. for 3 hours, a light emitting device of Example 1 in which a CaO.6Al ₂ O ₃ : Mn phosphor was applied on the surface was produced.
[0020]
When the electrodes of the light emitting device of Example 1 obtained as described above were energized, red light emission having a light emission chromaticity point represented by the CIE color system of x = 0.711 and y = 0.281 was obtained. Was obtained. FIG. 1 shows a spectrum analysis of the color tone of the light emitted from the phosphor layer at this time. The light emission peak wavelength has a strong peak at 656 nm in a long wavelength range, and the red color is strong in red and is preferable in color purity. Is shown.
[0021]
[Comparative Example 1]
A light emitting device was manufactured in the same manner as in Example 1 except that only the phosphor was changed to the conventional phosphor Y ₂ O ₃ S: Eu. When the electrodes of the light emitting device of Comparative Example 1 obtained as described above were energized, the emission chromaticity point represented by the CIE color system was x = 0.669 and y = 0.328. Was obtained. Fig. 1 shows the color tone of the light emission from the phosphor layer at this time, and the light emission peak wavelength has a strong peak at 624 nm, which is a long wave due to the orange side. It was not satisfactory in terms of reproduction.
[0022]
[Example 2]
The red phosphor CaO.6Al ₂ O ₃ : Mn of the present invention, the blue phosphor (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu and the green phosphor ZnS: Cu, Al are mixed. A light emitting device was manufactured in the same manner as in Example 1 using the white phosphor prepared as described above.
When the electrodes of the light emitting device of Example 1 thus obtained were energized, the emission chromaticity point represented by the CIE color system was x = 0.310 y = 0.396, and the white chromaticity normally used In addition, the color projected under illumination is good, and the spectrum of the emission obtained therefrom shows that the emission peak wavelength of the red component is located at 650 nm, which is the preferred red wavelength, from FIG. Was confirmed.
[0023]
[Comparative Example 2]
Conventionally, as a white phosphor using a red phosphor, a red phosphor Y ₂ O ₃ S: Eu, a blue phosphor (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu and a green phosphor ZnS are used. A light emitting device was manufactured in the same manner as in Example 2 except that a white phosphor prepared by mixing Cu and Al was used.
When the electrodes of the light emitting device of Comparative Example 2 thus obtained were energized, the emission chromaticity point represented by the CIE color system was x = 0.318 y = 0.386, and the white chromaticity normally used Points are shown. The color projected under illumination was not satisfactory in terms of red color reproduction. FIG. 2 shows the result of spectral analysis of the obtained light emission.
[0024]
【The invention's effect】
As described above, the red color of Example 1 and Example 2 of the present invention is 650 nm, which is the preferred red wavelength for the emission peak wavelength of the red component, as compared with Comparative Example 1 and Comparative Example 2 using the prior art. And good in color purity.
Therefore, the present invention adopts the above-described configuration, does not use a harmful substance such as mercury as a constituent element, and has a wide color reproduction and excellent color rendering properties as a multicolor and white light source that replaces a fluorescent lamp with low power consumption. To provide a light emitting device.
[Brief description of the drawings]
FIG. 1 illustrates an emission spectrum of an aluminate phosphor CaO.6Al ₂ O ₃ : Mn and a comparative red phosphor Y ₂ O ₂ S: Eu used in a light emitting device of the present invention at an excitation wavelength of 382 nm. It is a graph.
FIG. 2 shows a white phosphor produced using the aluminate phosphor CaO.6Al ₂ O ₃ : Mn of the present invention and a white phosphor produced using the conventional red phosphor Y ₂ O ₂ S: Eu. It is a graph which illustrates the luminescence spectrum at the excitation wavelength of 382nm of the light obtained with the body luminescence light source device.
FIG. 3 is a schematic sectional view showing one embodiment of the light emitting device of the present invention.
FIG. 4 is a schematic sectional view showing another embodiment of the light emitting device of the present invention.

Claims (5)

A near-ultraviolet or short-wavelength excitation light source having a peak wavelength of an emission spectrum in a visible wavelength region, and at least a part of the emission from the excitation light source arranged at a position capable of absorbing the emission from the excitation light source. And at least one kind of phosphor that emits light of a peak wavelength different from the above, wherein the composition of the red light-emitting phosphor is (M _1−x M ′ _{x ) O · n (Al 1-} y Ga y) 2 O 3: Mn z ( where M = Ca, Sr, M ' = Ba, Mg, Zn, 0 ≦ x ≦ 0.1,0 ≦ y ≦ 0.1 ^1. A light emitting device, which is an aluminate of 1 × 10 ⁻⁴ ≦ z ≦ ¹ × 10 ⁻¹ (g.atm / base 1 mol) and 2 ≦ n ≦ 8). A near-ultraviolet or short-wavelength excitation light source having a peak wavelength of an emission spectrum in a visible wavelength region, and at least a part of the emission from the excitation light source arranged at a position capable of absorbing the emission from the excitation light source. And three types of red, green, and blue phosphors that emit light of different peak wavelengths from each other, wherein the red light-emitting phosphor is (M _1−x M ′ _x ). _{O · n (Al 1-y} Ga y) 2 O 3: Mn z ( where M = Ca, Sr, M ' = Ba, Mg, Zn, 0 ≦ x ≦ 0.1,0 ≦ y ≦ 0.1, A white light emitting device, wherein 1 × 10 ⁻⁴ ≦ z ≦ ¹ × 10 ⁻¹ (g.atm / base 1 mol), 2 ≦ n ≦ 8). The light emitting device according to claim 1, wherein a peak wavelength of an emission spectrum of the excitation light source is 300 to 500 nm. The light emitting device according to claim 1, wherein the excitation light source is at least one of a light emitting diode (LED) and a semiconductor laser. The light emitting device according to claim 1, wherein the excitation light source is (In, Ga) N.

Images