JP2005298805A - Light emitting device and illumination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device comprising a combination of a stimulation source for generating light of 400 to 600 nm and a phosphor which is excellent in temperature characteristics and heat stability. <P>SOLUTION: The light emitting device has the first light emitting body which generates light of 400 to 600 nm and the second light emitting body which generates visible light by irradiation of the light from this first light emitting body, wherein this second light emitting body comprises a phosphor having a crystalline phase having a chemical composition of general formula 1: Eu<SB>a</SB>Ca<SB>b</SB>Sr<SB>c</SB>M<SB>d</SB>S<SB>e</SB>as a wavelength conversion material. (In the formula, M represents at least a kind of element chosen from Ba, Mg, and Zn, suffixes a, b, and d are numbers to satisfy the relations of 0.0002≤a≤0.02, 0.3≤b≤0.9998, and 0≤d≤0.1 respectively, and suffixes a, b, c, and d satisfy (a+b+c+d)=1, and e is a number to satisfy 0.9≤e≤1.1). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light emitting device used for a lighting device or the like. Specifically, the first light emitter that emits light in the visible light region from ultraviolet light by the power source, and the light in the visible light region is absorbed from the ultraviolet light from the first light emitter to emit long wavelength visible light. As a wavelength conversion material, the base compound can be combined with a second light emitter containing a phosphor having a specific composition having an emission center ion, and can generate high-intensity light regardless of the use environment, and is heat resistant. The present invention also relates to an excellent light-emitting device, an image display device including the light-emitting device, and an illumination device.

 Light sources such as gallium nitride (GaN) light-emitting diodes (LEDs) and laser diodes (LDs), which are semiconductor light-emitting devices with low voltage and high emission intensity developed in recent years, and phosphors as wavelength conversion materials for these light sources A white light-emitting device composed of a combination with the above has been proposed as a light-emitting source of an image display device or a lighting device, taking advantage of the feature of low power consumption and long life. For example, Japanese Patent Application Laid-Open No. 10-242513 discloses a light emitting device that uses a nitride semiconductor LED or LD chip as a light source and combines a phosphor of yttrium, aluminum, and garnet as a phosphor. However, this apparatus has also been proposed a phosphor suitable for emitting white light by combining a semiconductor blue light source and yellow light emission of the phosphor. However, this white light emission method using a mixed color of [blue + yellow] has the principle drawback that high color rendering is never obtained.

For this reason, in recent years, these semiconductor LEDs and LDs receive near-ultraviolet light and combine phosphors that emit blue, red, and green light, respectively, or receive blue light from blue LEDs and receive green and red light respectively. There has been proposed a phosphor suitable for emitting white light having high color rendering properties by combining phosphors that emit light. For example, Japanese Patent Laid-Open No. 2003-243715 shows a red phosphor whose main constituent element is (Ca, Sr, Eu) S, and in the examples, the composition is (Ca, Sr) _0.95 S: Eu _0. The phosphor of _{No. 05} is manufactured, and the Eu concentration is effective in the range of 0.1 or less, but it is also described that the optimum Eu concentration is particularly in the range of 0.005 to 0.01.

Furthermore, in JP 2002-60747, CaS or SrS with Eu as a dopant can be used as a red phosphor, and in one embodiment, the amount of dopant in the host lattice is about 0.1 mol. % To about 8 mol%, and the dopant concentration in SrS is preferably about 0.3 mol% to about 0.8 mol%.
By the way, when the LED or LD emits light, the surface temperature of the LED or LD is as high as about 120 ° C., and the phosphor located in the vicinity thereof is also placed at a high temperature of around 67 ° C. At present, the development of phosphors taking into account the above has not progressed.
Japanese Patent Laid-Open No. 10-242513 JP 2003-243715 A JP 2002-60747 A

  In view of such circumstances, the present invention aims to develop a light emitting device that is practically excellent in thermal stability and suitable for actual use in terms of temperature, is easy to manufacture, and provides high color rendering. And it is providing the double light-emitting type light-emitting device with high luminous intensity.

  As a result of intensive studies to solve the above problems, the present inventors can find a red phosphor that not only has excellent emission intensity but also has excellent thermal stability and temperature characteristics. ] + [Green] + [Red] or [Blue] + [Yellow] + [Red] is a mixed color of white light emitting device with very high color rendering and excellent thermal stability Reached. That is, in an example using a GaN-based blue LED as a light source, a combination of [green] + [red] phosphors or [yellow] + [red] phosphors with respect to a light emission source of 420 nm to 480 nm of LEDs. For example, in the case of a GaN-based near-ultraviolet light source, a combination of [blue] + [green] + [red] phosphors with respect to an emission source of 350 nm to less than 420 nm, or [ A method using a combination of phosphors of [blue] + [yellow] + [red] was considered.

  As a result of further intensive studies, the inventors of the present invention have a first light emitter that generates light of 400 to 600 nm, and a second light emitter that generates visible light when irradiated with light from the first light emitter. When a phosphor containing a crystal phase having a specific chemical composition is used as the wavelength conversion material in the second phosphor, the phosphor emits light in the vicinity of 400 to 600 nm from the first phosphor. It was found that the above-mentioned purpose can be achieved by emitting red light with high intensity. That is, by using a (Ca, Sr) S-based phosphor activated with Eu containing a crystal phase having a specific chemical composition as the second luminous body, an extremely high intensity in the wavelength region 600-680 nm. Red light is emitted, and since the phosphor is excellent in temperature characteristics and thermal stability, the entire device has excellent temperature characteristics and thermal stability, high color rendering properties, and high intensity white light. It has been found that the above object can be achieved, and the present invention has been achieved.

  The present invention has been made on the basis of such knowledge, and the gist thereof is that a first light-emitting body that generates light of 400 to 600 nm and generation of visible light by irradiation of light from the first light-emitting body. The second light emitter includes a phosphor having a crystal phase represented by a chemical composition represented by the following general formula [1]. And an image display device or a lighting device including the light emitting device.

_{Eu a Ca b Sr c M d} S e ······ [1]
[Wherein, M represents at least one element selected from Ba, Mg, and Zn, and a, b, and d are 0.0002 ≦ a ≦ 0.02, 0.3 ≦ b ≦ 0.9998, and 0, respectively. ≦ d ≦ 0.1 is satisfied, a, b, c, and d satisfy (a + b + c + d) = 1, and e is a number that satisfies 0.9 ≦ e ≦ 1.1. ]

  According to the present invention, it is possible to provide a light emitting device that is useful for a lighting device or an image display device and has excellent thermal stability, high color rendering properties, and high light emission intensity.

Hereinafter, the present invention will be described in detail.
The light-emitting device of the present invention is a light-emitting device having a first light-emitting body that generates light of 400 to 600 nm and a second light-emitting body that generates visible light when irradiated with light from the first light-emitting body. Then, a phosphor containing a crystal phase represented by the chemical composition of the following general formula [1] is used as the wavelength conversion material in the second luminous body.

_{Eu a Ca b Sr c M d} S e ······ [1]
[In the formula [1], M represents at least one element selected from Ba, Mg and Zn, and a, b and d are 0.0002 ≦ a ≦ 0.02 and 0.3 ≦ b ≦ 0.9998, respectively. , And 0 ≦ d ≦ 0.1, a, b, c, and d satisfy (a + b + c + d) = 1, and e satisfies 0.9 ≦ e ≦ 1.1. It is. ]

The (Ca, Sr) S-based phosphor activated by Eu containing the crystal phase having the chemical composition represented by the above general formula [1] in the present invention has a high intensity and wavelength when irradiated with light having a wavelength of 400 to 600 nm. Since it emits red light of 600-680 nm and is excellent in temperature characteristics and thermal stability, the temperature characteristics and thermal stability of the entire apparatus can also be improved.
In the general formula [1], the chemical formula amount a of Eu is preferably in the range of 0.0002 ≦ a ≦ 0.02 from the viewpoint of thermal stability, but more in the range of 0.0004 ≦ a ≦ 0.02. The range of 0.0004 ≦ a ≦ 0.008 is more preferable.

  From the viewpoint of temperature characteristics, the chemical formula amount a of Eu in the general formula [1] is preferably in the range of 0.0004 ≦ a ≦ 0.01, and more preferably in the range of 0.0004 ≦ a ≦ 0.007. Preferably, a range of 0.0004 ≦ a ≦ 0.005 is more preferable, a range of 0.0004 ≦ a <0.0045 is particularly preferable, and a range of 0.0004 ≦ a ≦ 0.004 is most preferable.

From the viewpoint of emission intensity, the chemical formula amount a of Eu in the general formula [1] is preferably in the range of 0.0004 ≦ a ≦ 0.02, and more preferably in the range of 0.001 ≦ a ≦ 0.008. If the content of the luminescent center ion Eu ²⁺ is less than this range, the emission intensity tends to be small. On the other hand, if the content exceeds this range, the emission intensity tends to decrease due to a phenomenon called concentration quenching. .
In order to combine all of thermal stability, temperature characteristics, and emission intensity, the chemical formula amount a of Eu in the general formula [1] is preferably in the range of 0.0004 ≦ a <0.0045, and 0.0004 ≦ a ≦ The range of 0.004 is more preferable, and the range of 0.001 ≦ a ≦ 0.004 is more preferable.

  The phosphor having the crystal phase of the chemical composition represented by the general formula [1] is mainly (Ca, Sr) S: Eu, but when the Sr in the composition is increased, the emission peak wavelength is shifted to the short wavelength side. . That is, the smaller the Sr, the longer the wavelength and the deep red light emission. Therefore, a phosphor that emits desired red light can be obtained by appropriately adjusting the amount of Sr. On the other hand, when used in a white light emitting device to be described later, it is preferable that the red component constituting the white light is not shifted to the short wavelength side from the viewpoint of vividness of the white light. It is preferable that the chemical formula amount c of Sr does not contain Sr, that is, c = 0.

Crystalline phase containing the phosphor used in the present invention is a chemical composition represented by the general formula [1], in the basic crystal _{Eu a Ca b Sr c M d} S e is Eu, Ca, Sr or M The molar ratio of the cation site occupied by and the anion site occupied by S is usually 1: 1. However, even if some cation deficiency or anion deficiency occurs, the target fluorescence performance is not greatly affected. Therefore, the chemical formula amount e of S in the general formula [1], that is, the molar ratio e of anion sites occupied by S is In the present invention, phosphors in the range of 0.9 ≦ e ≦ 1.1 can be used.

In the chemical composition of the general formula [1], at least one element selected from Ba, Mg, and Zn represented by M is not necessarily an essential element, but the chemical formula amount d of M is 0 ≦ d. The phosphor contained in the range (molar ratio) of ≦ 0.1 can also achieve the object of the present invention.
Further, the phosphor of the present invention may contain elements other than Eu, Ca, Sr, Ba, Mg, Zn, and S in an amount of 1% by weight or less in the crystal phase due to impurities in the raw material. As long as these elements do not affect the fluorescence performance, there is no particular problem in use.

The phosphor having a crystal phase having the chemical composition represented by the general formula [1] used in the present invention can be prepared by a conventional method. For example, a Ca source, a Sr source, a Ba source, a Mg source, a Zn source, a compound of an S source, and an element source compound of a luminescent center ion (Eu) from which the constituent element in the general formula [1] is derived Prepared by dry mixing such as roll mill, ball mill, jet mill, etc. or dry blending method combining pulverization using a mortar and pestle with a blender such as ribbon blender, V-type blender, Henschel mixer, etc. It can manufacture by heat-processing the fired mixture and baking.
If the element source compound is not sulfide, use a pulverizer or mortar and pestle, etc., add a liquid medium such as water and wet mix in a slurry state or solution state, then spray the prepared mixture It can also be produced by heat-treating and baking a mixture obtained by a wet mixing method in which drying, heat drying, natural drying, or the like is performed.

The heat treatment method of the mixture obtained by these dry mixing methods or wet mixing methods is usually 600 to 1400 ° C., preferably 700 to 1300 ° C., more preferably in a heat-resistant container such as a crucible or tray made of alumina or quartz. Is performed by heating at a temperature of 900 to 1100 ° C. for 10 minutes to 24 hours in a specific atmosphere.
The specific heating atmosphere includes an ionic state (valence) in which the element of the emission center ion contributes to light emission from a single or mixed atmosphere of gases such as hydrogen sulfide, air, oxygen, carbon monoxide, carbon dioxide, nitrogen, hydrogen, and argon. The atmosphere required to obtain a number) is selected. In the case of the divalent Eu or the like in the phosphor of the present invention, a neutral or reducing atmosphere such as hydrogen sulfide, carbon monoxide, nitrogen, hydrogen, and argon is preferable. Even if you choose.
In addition, after heat processing, washing | cleaning, drying, a classification process, etc. are made | formed as needed.

Examples of the raw material compound that becomes each element source compound of the constituent elements Ca, Sr, Ba, Mg, Zn, and Eu in the phosphor of the present invention include Ca, Sr, Ba, Mg, Zn, and Eu sulfides, oxidation Compounds, hydroxides, carbonates, nitrates, sulfates, oxalates, carboxylates, halides, etc., and compounds of S source include elements such as Ca, Sr, Ba, Mg, Zn and Eu Sulfides, oxysulfides, hydrogen sulfide, NH ₄ SH, CS ₂ , S, (CH ₃ ) ₂ NCS ₂ Na, and the like. These raw material compounds are selected in consideration of chemical composition, reactivity, non-generation of NO _x , SO _x, etc. during firing, etc., but the constituent elements sulfide, sulfate, carbonate An oxide or the like is preferable.

Specific examples of Sr and Ca raw material compounds include SrS, SrO, Sr (OH) ₂ .8H ₂ O, SrCO ₃ , Sr (NO ₃ ) ₂ , SrSO ₄ , Sr (OCO). ) ₂ · H ₂ O, Sr (OCOCH ₃ ) ₂ · 0.5H ₂ O, SrCl _{2 and the} like, among which SrS is preferable. As Ca source compounds, CaS, CaO, Ca (OH) ₂ , CaCO ₃ , Ca (NO ₃ ) ₂ .4H ₂ O, CaSO ₄ .2H ₂ O, Ca (OCO) ₂ .H ₂ O, Ca (OCOCH ₃ ) ₂ .H ₂ O, CaCl _{2 and the} like are mentioned, among which CaS is preferable.

Also, if specifically illustrated for Mg and Zn, as a Mg source _{compound, MgS, MgO, Mg (OH} ) 2, MgCO 3, Mg (OH) 2 · 3MgCO 3 · 3H 2 O, Mg (NO 3) ₂ · 6H ₂ O, MgSO ₄ , Mg (OCO) ₂ · 2H ₂ O, Mg (OCOCH ₃ ) ₂ · 4H ₂ O, MgCl _{2 and the} like, and Zn source compounds include ZnS, Zn ₂ OS, and ZnO. Zn (OH) ₂ , ZnCO ₃ , Zn (NO ₃ ) ₂ , Zn (OCO) ₂ , Zn (OCOCH ₃ ) ₂ , ZnCl _{2 and the} like. MgCO ₃ Among its, ZnCO ₃ is preferable.

Furthermore, specific examples of the element source compound for Eu, which is the element of the emission center ion, are Eu ₂ S ₃ , EuF ₃ , EuCl ₂ , EuCl ₃ , Eu ₂ O ₃ , Eu ₂ (SO ₄ ) ₃ , Eu ₂ (OCO) ₆ , Eu ₂ (CO ₃ ) _{3 and the} like can be mentioned, and EuF ₃ is preferable.

  In the light-emitting device of the present invention, as a method of combining the light-emitting source of the first light-emitting body and the phosphor of the second light-emitting body, the second light-emitting body is a phosphor and the general formula [1] of the present invention is used. A method of containing only a red phosphor containing a crystal phase having a chemical composition and used for illumination or display as a red light emitting device, or [blue] phosphor + [green] as a phosphor of a second light emitter Combination of phosphor + [red] phosphor of the present invention, or light from the first light emitter such as blue LED and [green] phosphor of the second light emitter + [red] phosphor of the present invention Depending on the combination, a method of using as a white light emitting device for illumination or display can be mentioned.

Examples of the [blue] phosphor to be combined with the [red] phosphor of the present invention include apatite activated by BaMgAl ₁₀ O ₁₇ : Eu, Ba ₃ MgSi ₂ O ₈ : Eu, Eu, and the like [green] Examples of the phosphor include, but are not limited to, BaMgAl ₁₀ O ₁₇ : Eu, Mn, ZnS: Cu, Al, and SrAl ₂ O ₄ : Eu.

  In the light emitting device of the present invention, a light emitter that emits light having a peak wavelength in a wavelength range of 400 to 600 nm is used as the first light emitter for irradiating the phosphor contained in the second light emitter. To do. When the first illuminant is a GaN-based illuminant, an illuminant that generates light having a peak wavelength in the wavelength range of 430 to 570 nm is preferable, and an illuminant that generates light having a peak wavelength in the range of wavelength 440 to 520 nm Is more preferable.

  Specific examples of the first light emitter include a light emitting diode (LED) or a laser diode (LD). Among them, a GaN LED or LD using a GaN compound semiconductor is preferable. This is because GaN-based LEDs and LDs have significantly higher light emission output and external quantum efficiency than SiC-based LEDs that emit light in this region, and are extremely bright with very low power when combined with the phosphor. This is because light emission can be obtained. For example, for a current load of 20 mA, the GaN system usually has a light emission intensity 100 times or more that of the SiC system.

GaN-based LEDs and LDs preferably have an Al _X Ga _Y N light emitting layer, a GaN light emitting layer, or an In _X Ga _Y N light emitting layer. Among these, a GaN-based LED having an In _X Ga _Y N light-emitting layer is particularly preferable because the light emission intensity is very strong. In a GaN-based LD, multiple layers of In _X Ga _Y N and GaN layers are preferable. The quantum well structure is particularly preferable because the emission intensity is very strong. In the above, the value of X + Y is usually a value in the range of 0.8 to 1.2. In the GaN-based LED, those in which the light emitting layer is doped with Zn or Si or those without a dopant are preferable for adjusting the light emission characteristics.
A GaN-based LED has these light-emitting layer, p-layer, n-layer, electrode, and substrate as basic components, and the light-emitting layer is made of n-type and p-type Al _X Ga _Y N layers, GaN layers, or In _X Those having a hetero structure sandwiched between Ga _Y N layers and the like have high luminous efficiency, and those having a hetero structure having a quantum well structure have higher luminous efficiency and are more preferable.

  In the present invention, it is particularly preferable to use a surface-emitting type light emitter, particularly a surface-emitting GaN-based laser diode (LD), as the first light-emitting body, because it increases the light emission efficiency of the entire light-emitting device. . A surface-emitting type illuminant is an illuminant that emits strong light in the surface direction of a film. In a surface-emitting GaN-based laser diode, the crystal growth of a light-emitting layer or the like is controlled, and a reflective layer or the like is successfully performed. By devising, the light emission in the surface direction can be made stronger than the edge direction of the light emitting layer. When the surface emitting type is used, the light emission cross-sectional area per unit light emission amount can be increased compared to the type that emits light from the edge of the light emitting layer. As a result, the phosphor of the second light emitter is irradiated with the light. Since the irradiation area can be made very large with the same amount of light and the irradiation efficiency can be improved, stronger light emission can be obtained from the phosphor included in the second light emitter.

  When a surface-emitting type is used as the first light emitter, the second light emitter is preferably a film. As a result, the cross-sectional area of the light from the surface-emitting type light emitter is sufficiently large. Therefore, when the second light emitter is formed into a film in the direction of the cross section, the irradiation cross-section area of the phosphor from the first light emitter is irradiated. Becomes larger per unit amount of phosphor, so that the intensity of light emitted from the phosphor can be further increased.

  Further, when a surface-emitting type is used as the first light emitter and a film-like one is used as the second light emitter, the second light emitter directly in the form of a film on the light-emitting surface of the first light emitter. It is preferable to have a shape in which is contacted. Contact here means creating a state where the first light emitter and the second light emitter are in close contact with each other without a gap layer of air or gas between the surfaces in contact with each other. As a result, it is possible to avoid a light amount loss in which light from the first light emitter is reflected by the film surface of the second light emitter and oozes out, so that the light emission efficiency of the entire apparatus can be improved.

  FIG. 1 is a schematic perspective view showing the positional relationship between the first light emitter and the second light emitter in an example of the light emitting device of the present invention. In FIG. 1, 1 is a film-like second light emitter having the phosphor, 2 is a surface-emitting GaN-based LD as the first light emitter, and 3 is a substrate. In order to create a state in which they are in contact with each other, the LD 2 and the second light emitter 1 may be formed separately, and their surfaces may be brought into contact with each other by an adhesive or other means. Alternatively, the second light emitter may be formed (molded). As a result, the LD 2 and the second light emitter 1 can be brought into contact with each other.

  The light from the first illuminant and the light from the second illuminant are usually directed in all directions. However, when the phosphor powder of the second illuminant is dispersed in the resin, the light is out of the resin. A part of the light is reflected when exiting, so the direction of the light can be adjusted to some extent. Therefore, since light can be guided to an efficient direction to some extent, it is preferable to use a phosphor in which the phosphor powder is dispersed in a resin as the second light emitter. Further, when the phosphor is dispersed in the resin, the total irradiation area of the light from the first light emitter to the second light emitter is increased, so that the light emission intensity from the second light emitter can be increased. It also has the advantage of being able to.

  Examples of the resin that can be used to disperse the phosphor used in the second luminous body include various resins such as silicon resin, epoxy resin, polyvinyl resin, polyethylene resin, polypropylene resin, and polyester resin. In view of good dispersibility and stability of the phosphor powder, silicon resin and epoxy resin are preferable. When the phosphor powder of the second phosphor is dispersed in the resin, the proportion of the phosphor powder is usually 3 to 95%, preferably 3 to 54%, more preferably based on the total weight of the phosphor and the resin. Is 3-12%. If the phosphor is too much, the luminous efficiency may be reduced due to aggregation of the powder, and if it is too little, the luminous efficiency may be lowered due to light absorption or scattering by the resin.

  The light-emitting device of the present invention is composed of a second light-emitting body containing the phosphor as a wavelength conversion material, and a light-emitting element (first light-emitting body) that generates light of 400 to 600 nm. A phosphor is a light-emitting device that absorbs light of 400 to 600 nm emitted from a light-emitting element, has good color rendering regardless of the use environment, and can generate high-intensity visible light. And a light source such as an image display device such as a color liquid crystal display or a lighting device such as a surface light emission.

  The light-emitting device of the present invention will be described with reference to the drawings. FIG. 2 is a schematic cross-sectional view showing an embodiment of a light-emitting device having a first light emitter (400-600 nm light emitter) and a second light emitter. 4 is a light emitting device, 5 is a mount lead, 6 is an inner lead, 7 is a first light emitter (400-600 nm light emitter), 8 is a phosphor-containing resin portion as a second light emitter, 9 Is a conductive wire, and 10 is a mold member.

  As shown in FIG. 2, the light emitting device as an example of the present invention has a general bullet shape, and a first light emitter made of a GaN-based light emitting diode or the like is disposed in the upper cup of the mount lead 5. (400-600 nm illuminant) 7 was formed as a second illuminant by mixing and dispersing the phosphor in a binder such as silicon resin, epoxy resin, or acrylic resin, and pouring it into the cup. It is fixed by being covered with the phosphor-containing resin portion 8. On the other hand, the first light emitter 7 and the mount lead 5, and the first light emitter 7 and the inner lead 6 are each electrically connected by a conductive wire 9, and these are entirely covered with a mold member 10 made of epoxy resin or the like, Protected.

  Further, as shown in FIG. 3, the surface emitting illumination device 11 incorporating the light emitting device shown in FIG. 2 is formed on the bottom surface of a rectangular holding case 12 whose inner surface is light-impermeable such as a white smooth surface. A large number of light emitting devices 13 are arranged on the outer side by providing a power source and a circuit (not shown) for driving the light emitting device 13, and milky white acrylic is provided at a position corresponding to the lid portion of the holding case 12. A diffusion plate 14 such as a plate is fixed for uniform light emission.

  Then, by driving the surface emitting illumination device 11 and applying a voltage to the first light emitter of the light emitting element 13, light of 400 to 600 nm is emitted, and a part of the light emission is used as the second light emitter. The phosphor in the phosphor-containing resin part absorbs and emits visible light, while light emission with high color rendering properties is obtained by mixing with blue light or the like that is not absorbed by the phosphor. 14, is emitted upward in the drawing, and illumination light with uniform brightness is obtained within the surface of the diffusion plate 14 of the holding case 12.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

Example 1
A mixture obtained by pulverizing and mixing CaS; 1.9981 g and EuF ₃ ; 0.0024 g in an agate mortar was calcined in an alumina crucible by heating at 1000 ° C. for 2 hours in a nitrogen-hydrogen mixed gas stream. Subsequently, the fired product was pulverized and subjected to classification treatment (particle size control by pulverization) to produce a red-emitting phosphor Eu _0.004 Ca _0.9996 S (Eu: 0.04 mol%).

Example 2
A phosphor Eu _0.001 Ca _0.999 S (Eu: 0.1 mol%) was produced in the same manner as in Example 1 except that the charged materials were changed to CaS; 3.9824 g and EuF ₃ ; 0.0108 g. did.
Example 3
A phosphor Eu _0.004 Ca _0.996 S (Eu: 0.4 mol%) was produced in the same manner as in Example 1 except that the charged raw materials were changed to CaS; 3.9594 g and EuF ₃ ; 0.0482 g. did.

Example 4
A phosphor Eu _0.008 Ca _0.992 S (Eu: 0.8 mol%) was produced in the same manner as in Example 1 except that the charged raw materials were changed to CaS; 3.8908 g and EuF ₃ ; 0.0913 g. did.
Example 5
A phosphor Eu _0.01 Ca _0.99 S (Eu: 1 mol%) was produced in the same manner as in Example 1 except that the charged raw materials were changed to CaS; 3.8936 g and EuF ₃ ; 0.1152 g.

Example 6
A phosphor Eu _0.02 Ca _0.98 S (Eu: 2 mol%) was produced in the same manner as in Example 1 except that the charged raw materials were changed to CaS; 3.77881 g and EuF ₃ ; 0.2257 g.

Comparative Example 1
A phosphor Eu _0.0001 Ca _0.9999 S (Eu: 0.01 mol%) was produced in the same manner as in Example 1 except that the charged raw materials were changed to CaS; 1.9936 g and EuF ₃ ; 0.0006 g. did.
Comparative Example 2
A phosphor Eu _0.05 Ca _0.95 S (Eu: 5 mol%) was produced in the same manner as in Example 1 except that the charged raw materials were changed to CaS; 1.7534 g and EuF ₃ ; 0.2700 g.

Comparative Example 3
A phosphor Eu _0.1 Ca _0.9 S (Eu: 10 mol%) was produced in the same manner as in Example 1 except that the charged raw materials were changed to CaS; 1.5668 g and EuF ₃ ; 0.5031 g.
Comparative Example 4
A phosphor Eu _0.18 Ca _0.82 S (Eu: 18 mol%) was produced in the same manner as in Example 1 except that the charged raw materials were changed to CaS; 1.3779 g and EuF ₃ ; 0.7106 g.

Comparative Example 5
A phosphor Eu _0.25 Ca _0.75 S (Eu: 25 mol%) was produced in the same manner as in Example 1 except that the charged raw materials were changed to CaS; 1.2272 g and EuF ₃ ; 0.8907 g.

  The phosphors produced in Examples 1 to 6 and Comparative Examples 1 to 5 were excited at 465 nm, which is the main wavelength of the GaN-based blue light-emitting diode, and the emission spectra were measured with a multispectrophotometer manufactured by JASCO Corporation. Table 1 shows the wavelength of the emission peak and the emission intensity (relative intensity) at that wavelength.

<Measurement of temperature characteristics and thermal stability>
The temperature characteristics and thermal stability of the phosphors produced in Examples 1 to 6 and Comparative Examples 1 to 5 were measured. The phosphors produced in Examples and Comparative Examples were excited at 465 nm, which is the dominant wavelength of a GaN-based blue light-emitting diode, and heated in a nitrogen atmosphere immediately after heating at 24 ° C. and 67 ° C. before heating and at 67 ° C. for 11 minutes and then cooled The luminance was measured using a luminance meter BM-5A manufactured by Topcon Corporation under the temperature condition at 24 ° C.
Table 1 shows the ratio of the luminance immediately after heating at 67 ° C. to the luminance at 24 ° C. before heating as a value representing the temperature characteristic (A). Further, as a value representing the thermal stability (B), the ratio of the luminance of the phosphor heated at 67 ° C. for 11 minutes and cooled to 24 ° C. with respect to the luminance at 24 ° C. before heating was described. However, the luminance at which the measured temperature deviated from 67 ° C. was corrected to the luminance at the previous and subsequent temperatures, and the luminance at 67 ° C. was obtained.

Example 7
Phosphor Ca _0.1992 Sr _0.7968 Eu _0.004 S was _obtained in the same manner as in Example except that the raw materials were changed to CaS; 0.2633 g, SrS; 1.7258 g and EuF ₃ ; 0.0152 g. Manufactured.
Example 8
Phosphor Ca _0.3984 Sr _0.5976 Eu _0.004 S in the same manner as in Example 7, except that the charged materials were changed to CaS; 0.5671 g, SrS; 1.4168 g and EuF ₃ ; 0.0171 g. Manufactured.

Example 9
Phosphor Ca _0.5976 Sr _0.3984 Eu _0.004 S in the same manner as in Example 7, except that the charged raw materials were changed to CaS; 0.9454 g, SrS; 1.0427 g and EuF ₃ ; 0.0181 g. Manufactured.
Example 10
Phosphor Ca _0.7968 Sr _0.1992 Eu _0.004 S in the same manner as in Example 7 except that the raw materials were changed to CaS; 1.3990 g, SrS; 0.5833 g and EuF ₃ ; 0.0204 g. Manufactured.

  The phosphors produced in Examples 3 and 7 to 10 were excited at 465 nm, which was the dominant wavelength of the GaN blue light emitting diode, and the emission spectra were measured with a multispectrophotometer manufactured by JASCO Corporation. Table 2 shows the wavelengths of these emission peaks and the emission intensity (relative intensity) at those wavelengths.

The figure which shows an example of the light-emitting device which made the film-like fluorescent substance contact or shape | mold to the surface emitting type GaN-type diode. The typical sectional view showing one example of the light emitting device constituted from the 2nd luminous body containing the fluorescent substance of the present invention, and the 1st luminous body (400-600 nm luminous body). 1 is a schematic cross-sectional view illustrating an example of a surface-emitting illumination device using a light-emitting device (light-emitting element) according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; 2nd light-emitting body 2; Surface emitting type GaN-type LED
3; Substrate 4; Light emitting device 5; Mount lead 6; Inner lead 7; First light emitter (light emitter of 400 to 600 nm)
8; Resin part containing phosphor of the present invention 9; Conductive wire 10; Mold member 11; Surface emitting illumination device 12 incorporating a light emitting element 12; Holding case 13; Light emitting device 14;

Claims (6)

In a light emitting device including a first light emitter that generates light of 400 to 600 nm and a second light emitter that generates visible light by irradiation of light from the first light emitter, the second light emitter includes: A light emitting device comprising a phosphor having a crystal phase represented by a chemical composition represented by the following general formula [1].
_{Eu a Ca b Sr c M d} S e ······ [1]
[Wherein, M represents at least one element selected from Ba, Mg, and Zn, and a, b, and d are 0.0002 ≦ a ≦ 0.02, 0.3 ≦ b ≦ 0.9998, and 0, respectively. ≦ d ≦ 0.1 is satisfied, a, b, c, and d satisfy (a + b + c + d) = 1, and e is a number that satisfies 0.9 ≦ e ≦ 1.1. ]   2. The light emitting device according to claim 1, wherein d in the general formula [1] is d = 0.   3. In the general formula [1], a satisfies 0.001 ≦ a ≦ 0.004, c is c = 0, and e is e = 1. The light-emitting device of description.   The light emitting device according to any one of claims 1 to 3, wherein the first light emitter is a laser diode or a light emitting diode.   An image display device comprising the light emitting device according to claim 1.   An illuminating device comprising the light emitting device according to claim 1.

Images