JP2008189700A - Nitride-based fluorescent material, oxynitride-based fluorescent material and light-emitting device produced by using the same - Google Patents

Nitride-based fluorescent material, oxynitride-based fluorescent material and light-emitting device produced by using the same Download PDF

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JP2008189700A
JP2008189700A JP2007022355A JP2007022355A JP2008189700A JP 2008189700 A JP2008189700 A JP 2008189700A JP 2007022355 A JP2007022355 A JP 2007022355A JP 2007022355 A JP2007022355 A JP 2007022355A JP 2008189700 A JP2008189700 A JP 2008189700A
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phosphor
nitride
based phosphor
oxynitride
light
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JP5412710B2 (en
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Shoji Hosokawa
昌治 細川
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Nichia Chem Ind Ltd
日亜化学工業株式会社
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00Energy efficient lighting technologies
    • Y02B20/16Gas discharge lamps, e.g. fluorescent lamps, high intensity discharge lamps [HID] or molecular radiators
    • Y02B20/18Low pressure and fluorescent lamps
    • Y02B20/181Fluorescent powders

Abstract

The present invention provides a red phosphor having a controllable particle size and good emission characteristics, and a light emitting device using the red phosphor.
A nitride-based phosphor or an oxynitride-based phosphor activated by europium that absorbs near-ultraviolet light or blue light and emits red light, and is represented by the following general formula: x, y, z, a, and b are in the following ranges, and further contain rare earth fluoride or rare earth chloride. The average particle diameter of the phosphor is preferably 5 μm or more and 10 μm or less.
Ca x Al y Si z O a N b: Eu 2+
0.5 ≦ x ≦ 3, 0.5 ≦ y ≦ 3, 0.5 ≦ z ≦ 9, 0 ≦ a ≦ 3, 0.5 ≦ b ≦ 3
[Selection] Figure 8

Description

  The present invention relates to a nitride-based phosphor, an oxynitride-based phosphor, and a light-emitting device using these used in lighting such as a light-emitting diode and a fluorescent lamp, a display, a backlight for liquid crystal, and the like, and particularly from near-ultraviolet light. The present invention relates to a nitride-based phosphor that emits red light when excited by blue light, an oxynitride-based phosphor, and a light-emitting device using these.

  A light emitting device that emits white light using a combination of a semiconductor light emitting element and a phosphor has been developed. White light emitted from the light emitting device is obtained by the principle of light color mixing. Specifically, there are the following two methods for emitting white light. (1) Exciting a yellow light emitting phosphor with blue light emitted from a light emitting element in a short wavelength side region of visible light. As a result, yellow light partially converted in wavelength and blue light not converted are mixed. Two colors that are complementary colors are mixed and appear as white to the human eye. (2) The R • G • B phosphor is excited by light in the short wavelength region from ultraviolet to visible light emitted from the light emitting element. The three colors are mixed and emitted as white light. However, the method (1) has a problem that the color rendering properties are low due to lack of green and red components.

In this situation, wavelength conversion to a high-brightness red color with an efficient excitation band over a wide range of areas that have the excitation light sources (1) and (2), that is, from the ultraviolet to the blue wavelength range of visible light. Possible phosphors have been developed (see, for example, Patent Document 1 and Patent Document 2).
JP 2006-63214 A JP 2005-336253 A

  However, in practice, it is important to form a phosphor layer in the device in order to efficiently excite the phosphors in the device and prevent the light emission from the device from varying. Specific examples include phosphor layer pattern formation, particle packing, particle dispersion, and coating of particles such as oxides, pigments and conductive materials. These conditions influence the display brightness of the device. To do.

  For example, in a light emitting device in which a phosphor and a semiconductor light emitting element are combined, a sealing material such as an epoxy resin or a silicon resin containing the phosphor is filled in the vicinity of the semiconductor light emitting element. At this time, it is preferable that the dispersed state of the phosphor in the sealing material is uniform, and that the amount of the phosphor coated around the light emitting element is uniform. This is because if the amount of the phosphor that is excited before the light emitted from the light-emitting element is emitted to the outside, the degree of wavelength conversion differs.

  The present invention has been made in view of such conventional problems. The main object of the present invention is a nitride-based phosphor and an oxynitride-based phosphor that are excited by an excitation light source in the ultraviolet to visible light region and can emit red light by wavelength conversion, and the particle size can be controlled. It is to provide a light emitting measure excellent in color reproducibility by combining with this phosphor.

A nitride-based phosphor or an oxynitride-based phosphor according to the first invention is a phosphor activated with europium, which absorbs near ultraviolet light or blue light and emits red light, and has the following general formula: X, y, z, a, and b are in the following ranges, and rare earth fluoride or rare earth chloride is contained.
Ca x Al y Si z O a N b: Eu 2+
0.5 ≦ x ≦ 3, 0.5 ≦ y ≦ 3, 0.5 ≦ z ≦ 9, 0 ≦ a ≦ 3, 0.5 ≦ b ≦ 3

  The nitride-based phosphor or oxynitride-based phosphor according to the second invention is the phosphor according to the first invention, characterized in that the rare earth element is contained in an amount of 1 ppm or more and 5% or less.

  The nitride-based phosphor or oxynitride-based phosphor according to the third invention is the phosphor according to the first or second invention, characterized in that chlorine or fluorine is contained in an amount of 1 ppm or more and 5% or less.

A nitride-based phosphor or an oxynitride-based phosphor according to a fourth aspect of the present invention is a phosphor activated with europium that absorbs near ultraviolet light or blue light and emits red light, and has the following general formula: X, y, z, a, b are in the following ranges, and at least one alkali metal element selected from the group of Li, Na, K, Rb, Cs, or a group of Mg, Sr, Ba It contains at least one alkaline earth metal.
Ca x Al y Si z O a N b: Eu 2+
0.5 ≦ x ≦ 3, 0.5 ≦ y ≦ 3, 0.5 ≦ z ≦ 9, 0 ≦ a ≦ 3, 0.5 ≦ b ≦ 3

  The nitride-based phosphor or oxynitride-based phosphor according to the fifth invention is the phosphor according to the fourth invention, and is at least one alkali metal element selected from the group consisting of Li, Na, K, Rb, and Cs Or at least one alkaline earth metal selected from the group consisting of Mg, Sr and Ba is contained in an amount of 1 ppm or more and 5% or less.

  The nitride-based phosphor or oxynitride-based phosphor according to the sixth invention is the phosphor according to the fourth or fifth invention, wherein an alkaline earth metal is contained in fluoride, chloride, or sulfate. It is characterized by that.

  The nitride-based phosphor or oxynitride-based phosphor according to the seventh invention is the phosphor according to the fourth or fifth invention, wherein an alkaline earth metal is contained in fluoride, chloride, or sulfate. It is characterized by that.

  The nitride-based phosphor or the oxynitride-based phosphor according to the eighth invention is the phosphor according to any one of the first to seventh inventions, and has an average particle size of 5 μm or more and 10 μm or less. And

  The nitride-based phosphor or oxynitride-based phosphor according to the ninth invention further contains boron.

  A light emitting device according to a tenth aspect of the present invention includes an excitation light source having a first emission spectrum that emits blue light from near ultraviolet rays, and a first emission spectrum that absorbs at least part of the first emission spectrum and emits a second emission spectrum. It is a light-emitting device which has a seed | species or 2 or more types of wavelength conversion members, Comprising: A wavelength conversion member has the fluorescent substance as described in any one of 1st-9th invention, It is characterized by the above-mentioned.

  By controlling the particle size of a nitride-based phosphor or oxynitride-based phosphor that has an excitation band over a wide range from the near-ultraviolet to the blue wavelength region and emits light in the red region and has very good luminous efficiency, The arrangement position can be designed. As a result, the light from the excitation light source can be efficiently wavelength-converted, and a light-emitting device without color unevenness can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a nitride-based phosphor, an oxynitride-based phosphor, and a light-emitting device using the same for embodying the technical idea of the present invention. The invention does not specify nitride-based phosphors, oxynitride-based phosphors, and light-emitting devices using the same as the following. In addition, the member shown by the claim is not what specifies the member of embodiment. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention unless otherwise specified, and are merely explanations. It is just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.

  The short wavelength region from near ultraviolet to visible light in this specification refers to a region near 240 nm to 500 nm. As the excitation light source, one having an emission peak wavelength at 240 nm to 480 nm can be used. Among these, it is preferable to use an excitation light source having an emission peak wavelength at 360 nm to 470 nm. In particular, it is preferable to use an excitation light source having a wavelength of 380 nm to 420 nm or 450 nm to 470 nm used in a semiconductor light emitting device. By using a semiconductor light emitting element as an excitation light source, it is possible to obtain a stable light emitting device that is highly efficient, has high output linearity with respect to input, and is resistant to mechanical shock.

  The relationship between the color name and chromaticity coordinates, the relationship between the wavelength range of light and the color name of monochromatic light, and the like comply with JIS Z8110. Specifically, 380 nm to 455 nm is blue purple, 455 nm to 485 nm is blue, 485 nm to 495 nm is blue green, 495 nm to 548 nm is green, 548 nm to 573 nm is yellow green, 573 nm to 584 nm is yellow, 584 nm to 610 nm is yellow red , 610 nm to 780 nm is red.

(Phosphor)
The nitride-based phosphor or oxynitride-based phosphor according to the present embodiment is activated by europium, and emits red light by absorbing near ultraviolet light or blue light. The phosphor of the general formula is M x Al y Si z O a N b: Eu 2+ (0.5 ≦ x ≦ 3,0.5 ≦ y ≦ 3,0.5 ≦ z ≦ 9,0 ≦ a ≦ 3, 0.5 ≦ b ≦ 3), and M is at least one selected from the group consisting of Mg, Zn, Ca, Sr, and Ba. Further, the phosphor contains various additive elements as a flux and, if necessary, boron. Furthermore, the average particle size is 5 μm or more and 10 μm or less.
The nitride-based phosphor or oxynitride-based phosphor according to the present embodiment absorbs light in the short wavelength side region of ultraviolet light or visible light, and the phosphor is on the longer wavelength side than the emission peak wavelength of excitation light. The emission peak wavelength is as follows. The light in the short wavelength region of visible light is mainly in the blue light region. Specifically, it is preferably excited by light from an excitation light source having an emission peak wavelength at 250 nm to 500 nm and emitting fluorescence having a peak wavelength in the wavelength range of 490 to 570 nm. This is because a phosphor with high luminous efficiency can be provided by using an excitation light source in this range. In particular, an excitation light source having a main emission peak wavelength at 250 nm to 420 nm or 420 nm to 500 nm is preferably used, and an excitation light source having an emission peak wavelength at 440 to 480 nm is more preferably used.

  Moreover, it is preferable that at least a part of the nitride-based phosphor or the oxynitride-based phosphor has a crystal. For example, since the structure of a glass body (amorphous) is loose, unless the reaction conditions in the production process can be controlled so as to be strictly uniform, the component ratio in the phosphor is not constant, and chromaticity unevenness occurs. Arise. On the other hand, the nitride-based phosphor or oxynitride-based phosphor according to the present embodiment is not a glass body but a crystalline powder or granule and is easy to manufacture and process. Further, since this phosphor can be uniformly dissolved in an organic medium, it is easy to adjust the light emitting plastic and the polymer thin film material. Specifically, the nitride-based phosphor or the oxynitride-based phosphor according to the present embodiment has at least 50% by weight, more preferably 80% by weight or more of crystals. This indicates the proportion of the crystalline phase having luminescent properties, and if it has a crystalline phase of 50% by weight or more, light emission that can withstand practical use can be obtained. Therefore, the more crystal phases, the better. As a result, the emission luminance can be increased and processing can be facilitated.

In the nitride-based phosphor or oxynitride-based phosphor according to the present embodiment, europium Eu, which is a rare earth, becomes the emission center. However, it is not limited to only europium, and a part of which is partially activated with other rare earth metals or alkaline earth metals and co-activated with Eu can be used. Eu 2+, which is a divalent rare earth ion, exists stably if an appropriate matrix is selected, and has the effect of emitting light.

(Phosphor material)
The nitride-based phosphor or oxynitride-based phosphor according to the present invention is manufactured by mixing various phosphor materials in a wet or dry manner. As the phosphor material, Ca, Si, Al, Eu, additive elements, B as required, or each compound is used. Each raw material will be described below.

  Ca of the phosphor composition is preferably used alone. However, a part of Ca can be replaced with Sr, Mg, Ba or the like. Thereby, the peak of the emission wavelength of the nitride-based phosphor or the oxynitride-based phosphor can be adjusted.

  Si is also preferably used alone, but a part of it can be substituted with Group IV elements C, Ge, Sn, Ti, Zr, and Hf. However, by using only Si, a nitride-based phosphor or an oxynitride-based phosphor that is inexpensive and has good crystallinity is obtained.

Al is also preferably used alone, but a part of it can be substituted with Group III elements Ga, In, V, Cr and Co. However, by using only Al, an inexpensive nitride-based phosphor or oxynitride-based phosphor with good crystallinity is obtained. However, Al nitride or Al oxide may be used. It is better to use purified materials, but commercially available products may be used. Specifically, aluminum nitride AlN can be used as the Al nitride, and aluminum oxide Al 2 O 3 can be used as the Al oxide.

  Eu of the activator is preferably used alone, but a part of Eu is Sc, Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu. May be substituted. By substituting a part of Eu with another element, the other element acts as a co-activation. By co-activation, the color tone can be changed, and the light emission characteristics can be adjusted. When using a mixture in which Eu is essential, the blending ratio can be changed as desired. Europium mainly has bivalent and trivalent energy levels, but nitride-based phosphors or oxynitride-based phosphors use Eu2 + as an activator for the base Ca.

Further, a Eu compound may be used as a raw material. In this case, it is better to use a purified raw material, but a commercially available product may be used. Specifically, europium oxide Eu 2 O 3 , metal europium, europium nitride, and the like can be used as Eu compounds. The raw material Eu may be an imide compound or an amide compound. Europium oxide preferably has a high purity, and commercially available products can also be used. The phosphor according to Example 1 uses divalent Eu as the center of light emission, but divalent Eu is easily oxidized and is generally commercially available with a trivalent Eu 2 O 3 composition.

  Furthermore, the raw materials for the additive elements that act as flux include alkali metals such as Li, Na, K, Rb, and Cs, alkaline earth metals such as Mg, Ca, Sr, and Ba, Y, Ce, Pr, Tb, Lu, and the like These rare earth metals alone or their fluorides, chlorides, carbonates, sulfates, etc. are used.

  The nitride-based phosphor or the oxynitride-based phosphor further includes a group I element composed of Cu, Ag, Au, a group III element composed of Al, Ga, In, Ti, Zr, Hf, Sn, and Pb. It is also possible to include 1 to 500 ppm of at least one element selected from Group IV elements, Group V elements composed of P, Sb and Bi, and Group VI elements composed of S. Since these elements are scattered at the time of firing in the production process, the amount added after firing is smaller than the initial amount added to the raw material. Therefore, it is preferable to adjust the amount added to the raw material to 1000 ppm or less. The luminous efficiency can be adjusted by adding these elements.

  The element added to the above-described nitride-based phosphor or oxynitride-based phosphor is usually added as an oxide or an oxide hydroxide, but is not limited thereto, and is not limited to metal, nitride, An imide, amide, or other inorganic salt may be used, or it may be contained in other raw materials in advance.

  Oxygen may be contained in the composition of the nitride-based phosphor according to the present embodiment. It is considered that oxygen is introduced from various oxides as raw materials, the raw materials are oxidized during firing, or adheres to and mixes with the phosphor after generation. In general, by controlling the molar ratio of oxygen in the composition, it is possible to change the crystal structure of the phosphor and shift the emission peak wavelength of the phosphor. However, from the viewpoint of luminous efficiency, it is preferable that the concentration of oxygen contained in the phosphor is small, and it is preferable that the oxygen concentration be 3 w% or less with respect to the mass of the product phase.

(Boron)
Boron can be contained in the nitride-based phosphor or the oxynitride-based phosphor according to the embodiment. In general, many nitride-based phosphors or oxynitride-based phosphors have a high melting point, and a solid phase reaction hardly causes a liquid phase and the reaction does not proceed smoothly in many cases. However, in the case of containing boron, the liquid phase formation temperature is lowered and the liquid phase is easily formed, so that the reaction is promoted, and further, the solid phase reaction proceeds more uniformly, so that the emission characteristics are excellent. It is considered that a phosphor can be obtained. The molar concentration of boron added to the nitride-based phosphor or the oxynitride-based phosphor is 0.5 mol or less, and preferably 0.3 mol or less. Furthermore, it shall be 0.001 or more. More preferably, the molar concentration of boron is 0.001 or more and 0.2 or less. This is because if the concentration is within this range, the above-described effects can be obtained, and the sintering does not become intense, and the light emission characteristics are not deteriorated in the crushing step. Since a boron compound is a substance having a high thermal conductivity, it is presumed that, when added to the raw material, the temperature distribution of the raw material becomes uniform during firing, the solid phase reaction is promoted, and the light emission characteristics are improved. As an addition method, it is possible to add and mix together at the time of mixing raw materials.

Boron, boride, boron nitride, boron oxide, borate, etc. can be used as the boron material of the phosphor. Specific examples of boron added to the phosphor material include B, BN, H 3 BO 3 , B 2 O 3 , BCl 3 , SiB 6 , and CaB 6 . A predetermined amount of these boron compounds is weighed and added to the raw material.

(Light emitting device)
Next, a light emitting device using the above phosphor as a wavelength conversion member will be described. Examples of the light emitting device include a lighting device such as a fluorescent lamp, and a display device such as a display and a radar. A semiconductor light emitting element is used as an excitation light source for the wavelength conversion member. Here, the light emitting element is used to include not only an element that emits visible light but also an element that emits near ultraviolet light, far ultraviolet light, or the like. In addition to the semiconductor light emitting element, an excitation light source having an emission peak wavelength in the short wavelength region from ultraviolet to visible light, such as a mercury lamp used in an existing fluorescent lamp, can be appropriately used as the excitation light source.

(Embodiment 1)
As a first embodiment of a light-emitting device, a bullet-type semiconductor light-emitting device including a light-emitting element that emits light in a short wavelength region from near ultraviolet to visible light is described as an excitation light source. The light emitting element is small in size, has high power efficiency, and emits bright colors. In addition, since the light emitting element is a semiconductor element, there is no fear of a broken ball. In addition, it has excellent initial drivability and is strong against vibration and repeated on / off lighting. Therefore, a light-emitting device that combines a light-emitting element and a nitride phosphor is preferable.

(Light emitting element)
The light emitting element has a semiconductor layer formed by sequentially laminating an n-type layer, an active layer, and a p-type layer made of a nitride semiconductor on a sapphire substrate. An n-pad electrode is formed on n-type semiconductors that are separated from each other and exposed on the line, while a p-pad electrode is formed on the p-ohmic electrode.

  Specifically, as the light emitting element, a semiconductor light emitting element in which a semiconductor layer is epitaxially grown on a growth substrate can be suitably used. Examples of the growth substrate include sapphire, but are not limited thereto, and known members such as spinel, SiC, GaN, and GaAs can be used. In addition, by using a conductive substrate such as SiC, GaN, or GaAs instead of an insulating substrate such as sapphire, the p electrode and the n electrode can be arranged to face each other.

The light emitting element includes various materials such as BN, SiC, ZnSe, GaN, InGaN, InAlGaN, AlGaN, BAlGaN, and BInAlGaN. Similarly, these elements can contain Si, Zn, or the like as an impurity element to serve as a light emission center. As a material of the light emitting layer, a nitride semiconductor (for example, a nitride semiconductor containing Al or Ga, a nitride semiconductor containing In or Ga, In X Al Y Ga 1-XY N (0 ≦ X ≦ 1, 0 ≦ Y ≦ 1, X + Y ≦ 1), etc. The semiconductor structure is preferably a homostructure having a MIS junction, PIN junction, pn junction, etc., a heterostructure, or a double heterostructure. Various emission wavelengths can be selected depending on the material of the semiconductor layer and its mixed crystal ratio, and by making the semiconductor active layer into a single quantum well structure or a multiple quantum well structure formed in a thin film that produces quantum effects, In addition, the light emitting element can emit light from the ultraviolet region to the visible light region, particularly a light emitting element having an emission peak wavelength in the vicinity of 350 nm to 550 nm. It is preferable to have a light emitting layer that can emit light having an emission wavelength that can efficiently excite a fluorescent substance.Here, a nitride semiconductor light emitting element is described as an example of the light emitting element, but the present invention is not limited thereto. It is not a thing.

  Specifically, the light emitting element is preferably a nitride semiconductor element containing In or Ga. This is because a light source corresponding to the excitation wavelength region of the nitride-based phosphor or the oxynitride-based phosphor according to Embodiment 1 can be provided. The light emitting element emits light having an emission peak wavelength in the short wavelength region from near ultraviolet to visible light, and at least one or more phosphors are excited by the light from the light emitting element to exhibit a predetermined emission color. In addition, since the light emitting element can narrow the emission spectrum width, it can efficiently excite the nitride-based phosphor or the oxynitride-based phosphor, and the color tone from the light-emitting device can be substantially reduced. It is also possible to emit an emission spectrum that does not affect the change.

  Thus, by using the light emitted from the light emitting element as an excitation light source, an efficient light emitting device with low power consumption compared to a conventional mercury lamp can be realized. In addition, the phosphor described above can be used in the light-emitting device according to Embodiment 1.

(Particle size)
The particle size of the nitride-based phosphor or oxynitride-based phosphor used in the light emitting device is preferably in the range of 1 μm to 20 μm, more preferably 2 μm to 15 μm. A phosphor having a particle size smaller than 1 μm tends to form an aggregate. On the other hand, a phosphor having a particle size range of 2 μm to 15 μm has a high light absorption rate and conversion efficiency. In this manner, the mass productivity of the light-emitting device is improved by including a phosphor having a large particle diameter and having optically excellent characteristics.

Here, the particle size refers to the average particle size obtained by the air permeation method. Specifically, in an environment with an air temperature of 25 ° C. and a humidity of 70%, a sample of 1 cm 3 is weighed and packed in a special tubular container, then a constant pressure of dry air is flowed, and the specific surface area is read from the differential pressure. It is a value converted into an average particle diameter. The average particle size of the phosphor used in the present embodiment is preferably in the range of 5 μm to 10 μm. Moreover, it is preferable that the phosphor having this average particle diameter value is contained frequently. In addition, since the nitride-based phosphor or the oxynitride-based phosphor according to Embodiment 1 has a larger phosphor particle size than before, the sedimentation rate in the resin of the light-emitting device is higher than before, and the excitation light source It becomes possible to arrange the phosphors closer to each other. At this time, it is preferable that the phosphors are evenly distributed in the vicinity of the excitation light source. As described above, by using a phosphor having a small variation in particle size and particle size distribution, color unevenness is further suppressed, and a light emitting device having a good color tone can be obtained.

  As a light-emitting device according to Embodiment 1 having the above structure, a bullet-type light-emitting device is shown in FIG. The light-emitting device 1 is in a concave cup 10 formed by a lead frame 4 made of a conductive member. The light-emitting device 2 is placed on the lead frame 4 and is emitted from the light-emitting element 2. A phosphor 3 that converts the wavelength of at least a part of the emitted light. The light-emitting element 2 uses a light-emitting element having an emission peak wavelength at about 270 nm to 500 nm. Positive and negative electrodes 9 formed on the light emitting element 2 are electrically connected to the lead frame 4 via conductive bonding wires 5. Further, the light emitting element 2, the lead frame 4, and the bonding wire 5 are covered with a shell-shaped mold 11 so that the lead frame electrode 4 a which is a part of the lead frame 4 protrudes. The mold 11 is filled with a light-transmitting resin 6, and the resin 6 contains a phosphor 3 that is a wavelength conversion member. The resin 6 is preferably a silicone resin composition, but an insulating resin composition having translucency such as an epoxy resin composition and an acrylic resin composition can also be used. If the lead frame electrode 4 a protruding from the resin 6 is electrically connected to the external electrode, light is emitted from the light emitting layer 8 contained in the layer of the light emitting element 2. The emission peak wavelength output from the light emitting layer 8 has an emission spectrum near 500 nm or less in the ultraviolet to blue region. Part of the emitted light excites the phosphor 3, and light having a wavelength different from the wavelength of the main light source from the light emitting layer 8 is obtained.

(Sedimentation state of phosphor in resin)
The phosphors 3 are preferably arranged at a substantially uniform ratio around the vicinity of the light emitting element 2. Thereby, light without color unevenness is obtained. The luminance and wavelength of the light emitted from the light emitting device 1 are determined by the particle size of the phosphor 3 sealed in the light emitting device 1, the uniformity after coating, the thickness of the resin containing the phosphor, and the like. to be influenced. Specifically, if the amount and size of the phosphor that is excited before the light emitted from the light emitting element 2 is emitted to the outside of the light emitting device 1 is unevenly distributed at the site in the light emitting device 1, Color unevenness occurs. Further, in the phosphor powder, light emission is considered to occur mainly on the particle surface. Therefore, if the average particle size is generally small, a surface area per unit weight of the powder can be secured and a reduction in luminance can be avoided. Further, the small-sized phosphor can diffuse and reflect light to prevent uneven color of the emitted color. However, on the other hand, the smaller the average particle size of the phosphor, the higher the tendency of aggregation of the phosphor dispersed in the resin, and there is concern about uneven distribution in the resin.

  On the other hand, the large particle size phosphor improves the light conversion efficiency. However, if there are too many large particle size phosphors precipitated due to their own weight in the medium, for example, the passage path of the wavelength-converted light is blocked, resulting in a loss of light energy of the light emitting device. Therefore, light can be extracted efficiently by controlling the amount and particle size of the phosphor.

  Further, it is more desirable that the phosphor disposed in the light emitting device 1 is resistant to heat generated from the light source and weather resistant that is not affected by the use environment. This is because the fluorescence intensity generally decreases as the temperature of the medium increases. This is because as the temperature rises, intermolecular collision increases and potential energy loss is caused by non-radiative transition deactivation. Furthermore, when the temperature of the solution rises, there may be a slight shift in the wavelength of the fluorescence spectrum.

  As will be described in detail later, phosphor 3 according to Embodiment 1 settles in resin 6 due to its own weight because of its large particle size. The phosphor 3 moves to the lower side in the light emitting device 1 and enters the substantially concave cup 10. Further, the phosphor 3 can be deposited in a region very close to the light emitting element 2. The reason why the phosphor 3 according to the present embodiment can be disposed extremely close to the light emitting element 2 is that the phosphor 3 is excellent in heat resistance. That is, there is a feature that the light emitting device 1 can be remarkably reduced in deterioration and extended in life. This effect is considered to occur because Al or B in addition to this is contained in the composition of the phosphor 3.

  Consider the thickness of the resin containing the phosphor described above. In the light emitting device 1 of FIG. 2 in the first embodiment, since the light emitting element 2 is placed at substantially the center of the bottom surface forming the opening in the cup 10, the light emitting element 2 is a resin containing a phosphor 3. 6 is embedded. In order for the light from the light emitting layer 8 to be wavelength-converted by the phosphor 3 without unevenness, the light from the light emitting element 2 only needs to pass through the phosphor-containing resin uniformly. That is, the phosphor-containing resin film through which light from the light emitting layer 8 passes may be made uniform. Therefore, the size of the cup 10 and the mounting position of the light emitting element 2 may be determined so that the distance from the periphery of the light emitting element 2 to the wall surface and upper part of the cup 10 is uniform. With the light emitting device 1 of FIG. 2, it becomes easy to uniformly adjust the film thickness of the resin 6 containing the phosphor 3.

  The large phosphor 3 according to Embodiment 1 is concentrated in the cup 10 on which the light emitting element 2 is placed. Specifically, it has an appropriate amount of distribution region in the mold 11, particularly in the vicinity of the light emitting element 2. As a result, light can be emitted to the outside of the light emitting device 1 without blocking the path of the light whose wavelength has been converted in the vicinity of the light emitting element 2. That is, light energy can be extracted efficiently. In order to realize this, it is also possible to employ a two-step process in which a resin containing the large phosphor 3 is first potted in the cup 10 and then a resin not containing the phosphor 3 is filled in the mold 11. .

(Embodiment 2)
Next, as a light emitting device according to Embodiment 2 of the present invention, a cap type light emitting device 20 is shown in FIG. In the light emitting device 20, the same members as those in the light emitting device according to Embodiment 1 are denoted by the same reference numerals, and the description thereof is omitted. The light emitting device 20 is configured by covering a cap 21 made of a light transmitting resin in which a phosphor 3a is dispersed on the surface of the mold 11 of the light emitting device 1 of the first embodiment.

  The cap 21 uniformly disperses the phosphor 3 a in the light transmissive resin 6. The resin 6 a containing the phosphor 3 a is molded into a shape that fits into the shape of the outer surface of the mold 11 of the light emitting device 20. Alternatively, a manufacturing method is also possible in which a light-transmitting resin 6a containing a predetermined in-mold phosphor is put, and then the light emitting device 20 is pushed into the mold and molded. As a specific material of the resin 6a of the cap 21, a transparent resin, silica gel, glass, an inorganic binder, etc. excellent in temperature characteristics and weather resistance such as an epoxy resin, a urea resin, and a silicone resin are used. In addition to the above, thermosetting resins such as melamine resins and phenol resins can be used. In addition, thermoplastic resins such as polyethylene, polypropylene, polyvinyl chloride, and polystyrene, thermoplastic rubbers such as styrene-butadiene block copolymer, segmented polyurethane, and the like can also be used. Further, a diffusing agent, barium titanate, titanium oxide, aluminum oxide or the like may be contained together with the phosphor. Moreover, you may contain a light stabilizer and a coloring agent. The phosphor 3a used for the cap 31 can be not only one type but also a mixture of a plurality of phosphors or a layered structure. The particle size of the phosphor 3a is preferably smaller than the particle size of the phosphor 3 disposed in the cup 10. This is because the phosphor 3a that does not settle due to its own weight can be arranged uniformly in the resin 6a.

  First, the light emitted from the light emitting element 2 excites the phosphor 3, and a part of the light after wavelength conversion excites the phosphor 3 a of the cap 21 and further undergoes wavelength conversion. The mixed color light of the light emitting element 2 and the phosphors 3 and 3a is emitted to the outside.

  Further, two or more kinds of phosphors may be contained in the resin 6. As a result, the wavelength of the main light source output from the light emitting layer is converted by the first phosphor 3, and a part of the wavelength-converted light excites the second phosphor 3a, and further wavelength-converted light. Can be obtained. By adjusting the composition of the plurality of phosphors 3 and 3a, the main light source, the light wavelength-converted by the first phosphor, the light wavelength-converted by the second phosphor, and the main light source directly The mixed color light having the wavelength converted by the two phosphors is emitted to the outside of the light emitting device 20. Further, various colors can be expressed by adjusting the amounts of the phosphors 3 and 3a.

(Embodiment 3)
Next, a light-emitting device according to Embodiment 3 of the present invention is shown in FIG. In this light emitting device 30, the same members as those in the light emission measures according to the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted. In the light emitting device 30 of FIG. 4, the resin 6 including the large phosphor 3 is filled only in the concave cup 10 formed by the lead frame 4, as in the first embodiment. Thereafter, the resin 11 containing the phosphor 3 a is filled in the mold 11. The phosphor 3 a preferably has a smaller particle size than the large phosphor 3 disposed in the cup 10. This is because the small particle phosphor 3a is uniformly arranged in the resin 6. Further, the small particle phosphor 3a is presumed to settle in the cup 10 due to some weight, but since it is a small particle, the passage of light converted by the large particle phosphor 3 is not blocked. . Therefore, the extraction efficiency of light emitted to the outside of the light emitting device 1 is not affected.

  In order to prevent the small particle phosphor 3a from entering the cup 10, the resin 6 containing the large phosphor 3a is potted into the cup 10, and after the resin 6 is cured, the small particle phosphor What is necessary is just to fill the resin 6 containing 3a. Moreover, although the same kind of both resin is preferable, characteristics, such as a viscosity, may differ. If different resins are used, the softness can be changed by utilizing the difference in temperature required for each resin to cure.

  Furthermore, when the resin 11 containing both the large particle phosphor 3 and the small particle phosphor 3a is filled in the mold 11, the large particle phosphor 3 settles first due to its own weight. That is, the large phosphor 3 is deposited nearer to the light emitting element 2 than the small particle phosphor 3a without filling the resin in two stages as described above. Therefore, it is also possible to guide the phosphors 3 and 3a to a desired position using the particle size difference between the phosphors 3 and 3a. At this time, the timing for curing the resin may be determined according to characteristics such as the viscosity of the resin and the particle sizes of the phosphors 3 and 3a.

(Embodiment 4)
Furthermore, as a light emitting device according to Embodiment 4 of the present invention, a surface mount type light emitting device 40 is shown in FIG. FIG. 5A is a plan view, and FIG. 5B is a cross-sectional view. As the light-emitting element 101, an ultraviolet-excited nitride semiconductor light-emitting element can be used. The light-emitting element 101 may be a blue-excited nitride semiconductor light-emitting element. Here, the light emitting element 101 excited by ultraviolet light will be described as an example. The light emitting element 101 uses a nitride semiconductor light emitting element having an InGaN semiconductor with an emission peak wavelength of about 370 nm as a light emitting layer. The light-emitting element 101 includes a p-type semiconductor layer and an n-type semiconductor layer (not shown), and the p-type semiconductor layer and the n-type semiconductor layer have a conductive wire 104 connected to the lead electrode 102. Is formed. An insulating sealing material 103 is formed so as to cover the outer periphery of the lead electrode 102 to prevent a short circuit. A light-transmitting window 107 extending from a Kovar lid 106 at the top of the package 105 is provided above the light emitting element 101. A coating member 109 containing a phosphor 108 is applied to almost the entire inner surface of the translucent window 107. The phosphor 3 sinks in the coating member 109 due to its own weight, and can uniformly cover the bottom surface region of the window portion 107. Accordingly, light from the light emitting element 101 is converted without uneven distribution, and color unevenness of light emitted from the light emitting device can be reduced.

  As a specific LED light emitting element 101 structure, an n-type GaN layer which is an undoped nitride semiconductor on a sapphire substrate, a GaN layer where an Si-doped n-type electrode is formed to become an n-type contact layer, an undoped nitride The single quantum well structure includes an n-type GaN layer that is a semiconductor, an n-type AlGaN layer that is a nitride semiconductor, and then an InGaN layer that constitutes a light-emitting layer. On the light emitting layer, an AlGaN layer as a p-type cladding layer doped with Mg and a GaN layer as a p-type contact layer doped with Mg are sequentially laminated. (Note that a buffer layer in which a GaN layer is formed at a low temperature is formed on a sapphire substrate. The p-type semiconductor is annealed at 400 ° C. or higher after film formation.) Nitriding on the sapphire substrate by etching The surface of each pn contact layer is exposed on the same side of the physical semiconductor. An n-electrode is formed in a strip shape on the exposed n-type contact layer, and a translucent p-electrode made of a metal thin film is formed on almost the entire surface of the p-type contact layer that remains without being cut. A pedestal electrode is formed on the p-electrode in parallel with the n-electrode using a sputtering method.

  Next, each electrode of the die-bonded light emitting element 101 and each lead electrode 102 exposed from the bottom of the package recess are electrically connected by a conductive wire 104 such as an Ag wire. After sufficiently removing moisture in the recess of the package, sealing is performed with a Kovar lid 106 having a glass window 107 at the center, and seam welding is performed. In the glass window portion, a nitride phosphor or oxynitride phosphor 3, 3a, which is a wavelength conversion member, is previously contained in a slurry composed of 90 wt% nitrocellulose and 10 wt% γ-alumina. The color conversion member is configured by coating the back surface of the light window 107 and heating and curing at 220 ° C. for 30 minutes. The light output from the light emitting element 101 of the light emitting device 100 formed in this manner excites the phosphor 3, and a light emitting device capable of emitting a desired color with high luminance can be obtained. As a result, it is possible to obtain a light emitting device that is extremely easy to adjust the chromaticity and has excellent mass productivity and reliability.

  In Embodiment 4, the light in the ultraviolet region used as the excitation light source belongs to a portion having low visibility, and the light emission color of the light emitting device is substantially determined by the light emission color of the fluorescent material used. Further, even when a color shift of a light emitting element due to a change in input current or the like occurs, a color shift of a fluorescent material that emits light in a visible light region can be suppressed to be extremely small. Can do. Although the ultraviolet region generally has a wavelength shorter than 380 nm or 400 nm, light having a wavelength of 420 nm or less is hardly visible in terms of visibility, so that the color tone is not greatly affected.

(Embodiment 5)
FIG. 6A is a perspective view of a semiconductor light emitting device 40 according to an embodiment of the present invention. FIG. 6B is a cross-sectional view taken along the line BB ′ of the semiconductor light emitting device 1 shown in FIG. Hereinafter, an outline of the semiconductor light emitting device 40 of Example 5 will be described with reference to FIGS. The semiconductor light emitting device 40 is configured such that a package 12 having a space that opens in a substantially concave shape toward the top is mounted on the lead frame 4. Further, a plurality of light emitting elements 2 are mounted on the exposed lead frame 4 in the space of the package 12. That is, the package 12 is a frame that surrounds the light emitting element 2. In addition, a protective element 13 such as a Zener diode, which is energized when a voltage higher than a specified voltage is applied, is also placed in the open space of the package 12. Further, the light emitting element 2 is electrically connected to the lead frame 4 via bonding wires 5 and bumps. In addition, the open space of the package 12 is filled with the sealing resin 6.

  The phosphor 3 contained in the package 12 is shown in FIG. 6B (the phosphor 3 in FIG. 6A is omitted). As the phosphor 3, the above-described nitride-based phosphor or oxynitride-based phosphor can be used. As a result, the phosphor 3 can settle in the package 12 due to its own weight, and can be disposed very close to the light emitting element 2 as shown in FIG.

  Hereinafter, as an example of the present invention, a nitride phosphor or an oxynitride phosphor and a light emitting device using the same will be described, and the results of measuring the light emission characteristics will be described.

(Phosphor production method)
Phosphors of Examples 1-14, the general formula Ca x Al y Si z O a N b: Eu 2+ (0.5 ≦ x ≦ 3,0.5 ≦ y ≦ 3,0.5 ≦ z ≦ 9, 0 ≦ a ≦ 3, 0.5 ≦ b ≦ 3), and various additives and, if necessary, boron are added. Although an example of the manufacturing method of this fluorescent substance is demonstrated below, it is not limited to this manufacturing method.

(Examples 1-14, Comparative Example 1)
As an example of the phosphor, Examples 1 to 14 show nitride phosphors having a general formula represented by Ca 0.990 AlSiN 3.0 : 0.01Eu 2+ and added with various additive elements as flux.

  The composition of the nitride-based phosphor is set to Ca: Al: Si = 0.99: 1: 1. The Eu concentration is 0.01. Eu concentration is a molar ratio with respect to the molar concentration of Ca. The additive element concentration is 0.01. The additive element concentration is a molar ratio with respect to the molar concentration of Ca.

  The manufacturing method of the nitride fluorescent substance of Examples 1-14 and Comparative Example 1 is demonstrated using FIG. First, raw material Ca is pulverized (P1). The raw material Ca is preferably a simple substance, but compounds such as an imide compound and an amide compound can also be used. The raw material Ca may contain Li, Na, K, B, Al, or the like. The raw material is preferably purified. Thereby, since a purification process is not required, the manufacturing process of the phosphor can be simplified, and an inexpensive nitride-based phosphor can be provided. The raw material Ca is pulverized in a glove box in an argon atmosphere. As a guide for pulverizing Ca, the average particle size is in the range of 0.1 μm to 15 μm, preferably about 1 μm or more and 15 μm or less. However, it is not limited to this range. The purity of Ca is preferably 2N or higher, but is not limited thereto.

  Next, 20 g of raw material Ca is weighed and nitrided in a nitrogen atmosphere (P2). That is, a nitride of Ca can be obtained by nitriding raw material Ca at 600 ° C. to 900 ° C. for about 5 hours in a nitrogen atmosphere. The Ca nitride is preferably of high purity. This reaction formula is shown in Chemical Formula 1.

  Subsequently, the nitride of Ca is pulverized to 0.1 μm to 10 μm in a glove box in an argon atmosphere or a nitrogen atmosphere (P3).

On the other hand, the raw material Si is pulverized (P4). The raw material Si is preferably a simple substance, but a nitride compound, an imide compound, an amide compound, or the like can also be used. For example, Si 3 N 4 , Si (NH 2 ) 2 , Mg 2 Si, etc. The average particle size of the Si compound is preferably 0.1 μm to 15 μm, preferably in the range of about 1 μm to 15 μm from the viewpoints of reactivity with other raw materials, particle size control during and after firing, and the like. The purity of the raw material Si is preferably 3N or more, but may contain different elements such as Li, Na, K, B, Al and Cu. Next, 20 g of raw material Si is weighed, and nitriding is performed in a nitrogen atmosphere (P5). That is, silicon nitride is obtained by nitriding raw material Si at 800 ° C. to 1200 ° C. for about 5 hours in a nitrogen atmosphere. Silicon nitride is preferably highly pure. This reaction formula is shown in Chemical Formula 2.

  Further, the nitride of Si is pulverized to 0.1 μm to 10 μm in a glove box in an argon atmosphere or a nitrogen atmosphere (P6).

On the other hand, AlN is synthesized by Al nitridation or the like. When B is added, BN is synthesized by a direct nitridation method of B or the like. Next, Al nitride AlN, B nitride BN, and Eu compound Eu 2 O 3 as necessary are pulverized (P7). The average particle size after pulverization is 0.1 μm to 15 μm, preferably about 0.1 μm to 10 μm. However, AlN powder and BN powder that are already on the market can also be used.

Further, as additive elements, NaF which is an alkali metal fluoride, SrF 2 and BaF 2 which are alkaline earth metal fluorides, and CaCl 2 , SrCl 2 and BaCl 2 which are chlorides thereof, rare earth metal fluorides and YF 3 is chloride, CeF 3, PrF 3, TbF 3, LuF 3, YCl 3, was synthesized PrCl 3, it is also possible to use those commercially available (P8).

  After the pulverization, Ca nitride, Si nitride, Al nitride, and optionally B nitride, Eu oxide and additive element compounds are mixed at the mixing ratio shown in Table 1. Weigh and mix in a nitrogen atmosphere (P9). This mixing can also be done dry.

Specifically, the raw materials calcium nitride Ca 3 N 2 (molecular weight 148.26), aluminum nitride AlN (molecular weight 40.99), silicon nitride Si 3 N 4 (molecular weight 140.31), europium oxide Eu 2 O 3 , The mixing ratio (molar ratio) of each element of the compound of the additive element was measured so that Ca: Al: Si: Eu: addition element = 0.99: 1.00: 1.00: 0.01: 0.01 And mix. In Example 1, NaF was used as an additive element.

Further, Ca nitride, Al nitride, Si nitride, B nitride, Eu oxide as required, and alkali metals, alkaline earth metals, rare earth chlorides, fluorides, etc. to be added The compound of the additive element such as the above compound is fired in an ammonia atmosphere (P10). Specifically, the above mixture was put into a crucible, gradually heated from room temperature in an ammonia atmosphere, fired at about 1600 ° C. for about 5 hours, and then slowly cooled to room temperature. Thereby, the phosphor represented by Ca 0.990 Al 1.000 Si 1.000 N 3.000 : 0.010Eu can be obtained (P11).

  Moreover, oxygen may be contained in the composition of the phosphor of this example. It is considered that oxygen is introduced from various oxides as raw materials, the raw materials are oxidized during firing, or adheres to and mixes with the phosphor after generation. In general, by controlling the molar ratio of oxygen in the composition, it is possible to change the crystal structure of the phosphor and shift the emission peak wavelength of the phosphor. On the other hand, from the viewpoint of luminous efficiency, it is preferable that the oxygen concentration contained in the phosphor is small, and it is preferable that the oxygen concentration is 5 w% or less with respect to the mass of the product phase.

  For firing, a tubular furnace, a small furnace, a high-frequency furnace, a metal furnace, or the like can be used. The firing temperature can be in the range of 1200 ° C to 2000 ° C, but the firing temperature of 1400 ° C to 1800 ° C is preferred. For firing, it is preferable to use one-stage firing in which the temperature is gradually raised and firing is performed at 1200 to 1500 ° C. for several hours. However, the first-stage firing is performed at 800 to 1000 ° C. and heated gradually. Two-stage baking (multi-stage baking) in which the second baking is performed at 1200 to 1500 ° C. can also be used.

  The reducing atmosphere is an atmosphere containing at least one of nitrogen, hydrogen, argon, carbon dioxide, carbon monoxide, and ammonia. However, firing can be performed in a reducing atmosphere other than these.

  The target nitride-based phosphor can be obtained by the above manufacturing method. In addition, a Group II element such as Ca or Sr can be replaced with a part of Eu or in addition to Eu to form a nitride-based phosphor. Furthermore, Eu is a rare earth element, and a part of Eu is replaced with various rare earth elements, or in addition to Eu, rare earth elements such as La, Ce, Gd, Tb, Dy, Ho, Er, Tm, and Lu are used. It is also possible to make it a phosphor. As described above, an inexpensive phosphor having good crystallinity can be obtained. The reaction formula of the nitride-based phosphor of Example 1 by this firing is shown in Chemical Formula 3.

The added elements are not described because they are in trace amounts. Moreover, each additive element is changed, and it is set as the nitride type | system | group fluorescent substance of Examples 2-14 similarly. Tables 1 and 2 show additive elements according to each example. In Examples 1 to 6, 3% by weight of the additive element was added. In Examples 7 to 14, 1% by weight of the additive element was added. In Comparative Example 1, no additive element was added.
Further, this composition is a representative composition estimated from the blending ratio, and has sufficient characteristics to withstand practical use in the vicinity of the ratio. Moreover, the composition of the target phosphor can be changed by changing the blending ratio of each raw material.

The characteristics of the nitride-based phosphor according to each example and comparative example 1 were measured. Table 1 shows the light emission characteristics and the elemental analysis results when the phosphors of Examples 1 to 6 to which the alkali metal element and the alkaline earth metal element were added were excited by the excitation wavelength of 460 nm. In addition, Table 2 shows the emission characteristics and elemental analysis results when the phosphors of Examples 7 to 14 to which rare earth elements were added were excited with an excitation wavelength of 460 nm. Furthermore, in each Example, the light emission characteristics at the time of being excited by the excitation wavelength of 400 nm are shown in Tables 3 and 4. The relative luminance in each example is shown based on Comparative Example 1.
In addition, the particle diameter in the comparative example 1 and Examples 1-14 is F.R. S. S. S. No. (Fisher Sub Sieve Sizer's No.) refers to the average particle size obtained by the air permeation method. Specifically, in an environment with an air temperature of 25 ° C. and a humidity of 70%, a sample of 1 cm 3 is weighed, packed in a special tubular container, and then dried with a constant pressure, and the specific surface area is read from the differential pressure and averaged. It is a value converted into a particle size.

  As a result of elemental analysis of the phosphor of Example 7, it was confirmed that Y contained 6000 ppm and F contained 10 ppm or less. Moreover, it was confirmed from the elemental analysis result of Examples 1-14 that each additive element is comprised by the fluorescent substance. From the characteristics shown in the table, the phosphors of the examples were larger in particle size than the phosphor of Comparative Example 1, specifically 1.2 to 1.8 times. Some phosphors were confirmed to have increased luminance.

  Furthermore, FIG. 7 shows an excitation spectrum related to the phosphors of Comparative Example 1 and Example 1, FIG. 8 shows an emission spectrum at an excitation wavelength of 460 nm, and FIG. 9 shows an emission spectrum at an excitation wavelength of 400 nm. From the figure, the phosphor of Example 1 to which the flux of the additive element was added had almost no deviation in the spectrum wavelength range as compared with Comparative Example 1 without addition, and the energy in the emission spectrum by the excitation wavelength of 460 nm was found. The value rose. In this way, by controlling the particle size of the phosphor, for example, by increasing the particle size value, the phosphor can be settled near the light source in the light emitting device by its own weight. That is, the sedimentation state of the phosphor particles in the sealing resin in the light emitting device can be controlled, and for example, a uniform wavelength conversion layer can be formed near the light source. Thereby, the wavelength conversion amount of the emitted light from the light source can be made uniform, and the color unevenness of the emitted light can be reduced in the light emitting device containing the phosphor. In other words, by controlling the particle size of the phosphor, the phosphor distribution region can be controlled, so that a light emitting device with high color reproducibility can be obtained. In addition, since the use efficiency of materials and processes is increased by forming the phosphor layer only in a necessary portion, the productivity is high and many kinds of phosphors can be handled in the same process. The phosphor layer is preferably thinly coated with particles uniformly. This is because if the phosphor layer is too thick, the phosphor crystals overlap and cause shadowing, which reduces efficiency. From this point of view, the control of the particle size is significant, and a phosphor having a desired particle size can be obtained by appropriately changing the particle size by changing the production conditions such as the amount of additive element and the firing temperature.

  In addition, since the firing temperature required in the production of the nitride-based phosphor is high, a part of the phosphor may be sintered, and if the sintered phosphor is pulverized to form a powder, There is concern about a decrease in luminance. On the other hand, by using the above-mentioned flux, the production reaction of the nitride-based phosphor stable at high temperature can be promoted, and the reaction was sufficiently performed even at a lower firing temperature than usual.

(Effects caused by Al and B)
The nitride-based phosphor and the oxynitride-based phosphor according to this example can contain Al or B in addition to the composition. Thereby, since the peak wavelength can be made longer, even if the activation amount of europium which is an expensive rare earth element is reduced, light can be emitted in a deeper red color. Further, nitride phosphors and oxynitride phosphors containing Al or B in addition to the composition have heat resistance and can significantly reduce deterioration at high temperatures. Therefore, in a light emitting device using a nitride phosphor or oxynitride phosphor containing Al or B in addition to the composition, even if it is placed very close to the light emitting element, the lifetime is extremely long. There are features that can be done.

  Moreover, a 1000 times magnified photograph of the phosphor of Comparative Example 1 is shown in FIG. 10 (a), and a 5000 times magnified photograph is shown in FIG. 10 (b). Similarly, a 1000 × enlarged photo and a 5000 × enlarged photo of Example 1 are shown in FIGS. 11A and 11B, respectively. From the figure, it was confirmed that the average particle diameter of the phosphor of Example 1 was 2 μm to 15 μm, which was larger than that of Comparative Example 1.

  Nitride-based phosphors, oxynitride-based phosphors and light-emitting devices using these according to the present invention are fluorescent display tubes, displays, PDPs, CRTs, FLs, FEDs, projection tubes, etc., particularly blue light-emitting diodes or ultraviolet light-emitting diodes Can be suitably used for a white illumination light source, an LED display, a backlight light source, a traffic light, an illumination switch, various sensors, various indicators, and the like that have extremely excellent light emission characteristics.

It is a block diagram which shows the manufacturing method of the fluorescent substance of this invention. It is sectional drawing which shows the bullet-type light-emitting device concerning Example 1 of this invention. It is sectional drawing which shows the bullet-type light-emitting device concerning Example 2 of this invention. It is sectional drawing which shows the bullet-type light-emitting device which concerns on Example 3 of this invention. FIG. 5A is a plan view showing a surface-mounted light-emitting device according to Example 4 of the present invention, and FIG. 5B is a cross-sectional view showing the light-emitting device of FIG. FIG. 6A is a plan view showing a surface-mounted light emitting device according to Example 5 of the present invention, and FIG. 6B is a cross-sectional view showing the light emitting device of FIG. 3 is a graph of excitation spectra of phosphors according to Comparative Example 1 and Example 1. It is a graph of the emission spectrum at the time of exciting the fluorescent substance which concerns on the comparative example 1 and Example 1 at 460 nm. It is a graph of the emission spectrum at the time of exciting the fluorescent substance which concerns on the comparative example 1 and Example 1 at 400 nm. FIG. 10A is a 1000 times magnified photograph of the phosphor of Comparative Example 1, and FIG. 10B shows a 5000 times magnified photograph thereof. FIG. 11A is a 1000 × magnified photograph of the phosphor of Example 1, and FIG. 11B shows a 5000 × magnified photograph thereof.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light-emitting device 2 ... Light-emitting element 3 ... Large particle fluorescent substance 3a ... Small particle fluorescent substance 4 ... Lead frame 4a ... Lead frame electrode 5 ... Bonding wire 6 ... Resin 6a ... Resin 8 ... Light emitting layer 9 ... Electrode 10 ... Cup 11 DESCRIPTION OF SYMBOLS ... Mold 12 ... Package 13 ... Protection element 20 ... Light emitting device 21 ... Cap 30 ... Light emitting device 40 ... Light emitting device 100 ... Light emitting device 101 ... Light emitting element 102 ... Lead electrode 103 ... Insulating sealing material 104 ... Conductive wire 105 ... Package 106: Kovar lid 107 ... Translucent window (glass window)
109 ... Coating member

Claims (10)

  1. A nitride-based phosphor or an oxynitride-based phosphor activated with europium that absorbs near ultraviolet or blue light and emits red light;
    It is represented by the following general formula, and x, y, z, a, b are in the following ranges,
    A nitride-based phosphor or an oxynitride-based phosphor containing a rare earth fluoride or a rare earth chloride.
    Ca x Al y Si z O a N b: Eu 2+
    0.5 ≦ x ≦ 3, 0.5 ≦ y ≦ 3, 0.5 ≦ z ≦ 9, 0 ≦ a ≦ 3, 0.5 ≦ b ≦ 3
  2. The nitride-based phosphor or oxynitride-based phosphor according to claim 1,
    A nitride-based phosphor or oxynitride-based phosphor containing rare earth elements in an amount of 1 ppm to 5%.
  3. The nitride phosphor or oxynitride phosphor according to claim 1 or 2,
    A nitride phosphor or oxynitride phosphor containing chlorine or fluorine in an amount of 1 ppm to 5%.
  4. A nitride-based phosphor or an oxynitride-based phosphor activated with europium that absorbs near ultraviolet or blue light and emits red light;
    It is represented by the following general formula, and x, y, z, a, b are in the following ranges,
    A nitride system comprising at least one alkali metal element selected from the group consisting of Li, Na, K, Rb, and Cs, or at least one alkaline earth metal selected from the group consisting of Mg, Sr, and Ba Phosphor or oxynitride phosphor.
    Ca x Al y Si z O a N b: Eu 2+
    0.5 ≦ x ≦ 3, 0.5 ≦ y ≦ 3, 0.5 ≦ z ≦ 9, 0 ≦ a ≦ 3, 0.5 ≦ b ≦ 3
  5. The nitride-based phosphor or oxynitride-based phosphor according to claim 4,
    1 ppm or more and 5% or less of at least one alkali metal element selected from the group of Li, Na, K, Rb, and Cs, or at least one alkaline earth metal selected from the group of Mg, Sr, and Ba A featured nitride-based phosphor or oxynitride-based phosphor.
  6. The nitride-based phosphor or oxynitride-based phosphor according to claim 4 or 5,
    A nitride-based phosphor or an oxynitride-based phosphor, wherein the alkali metal element is contained in fluoride, chloride, or sulfate.
  7. The nitride-based phosphor or oxynitride-based phosphor according to claim 4 or 5,
    A nitride-based phosphor or an oxynitride-based phosphor, wherein the alkaline earth metal is contained in fluoride, chloride, or sulfate.
  8. The nitride-based phosphor or oxynitride-based phosphor according to any one of claims 1 to 7,
    A nitride-based phosphor or oxynitride-based phosphor having an average particle size of 5 μm or more and 10 μm or less.
  9. The nitride-based phosphor or oxynitride-based phosphor according to any one of claims 1 to 8,
    Further, a nitride-based phosphor or an oxynitride-based phosphor containing boron.
  10. An excitation light source having a first emission spectrum that emits blue light from near ultraviolet radiation;
    One or more wavelength conversion members that absorb at least a portion of the first emission spectrum and emit the second emission spectrum;
    A light emitting device comprising:
    The light emitting device, wherein the wavelength conversion member includes the nitride-based phosphor or the oxynitride-based phosphor according to any one of claims 1 to 9.
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