JP2007103818A - Light emitting device, phosphor for light emitting element and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device or the like which has superior durability and capability to obtain a high-quality optical output. <P>SOLUTION: The light emitting device is provided with a light emitting element and a phosphor arranged around the light emitting element so as to absorb at least a part of light emitted from the light emitting element, and to convert the absorbed light into distinct wavelength light. The phosphor is composed of a nitride system fluorescence material or an oxynitride system fluorescence material which contains nitrogen, and the front surface of the phosphor has a coating layer containing two or more different compounds. Such a coating with different compounds can reduce the deterioration of the phosphor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting device including a light emitting element and a phosphor that converts the wavelength of light emitted from the light emitting element, a phosphor for the light emitting element, and a method for manufacturing the phosphor, for example, a semiconductor light emitting element such as an LED or an LD, The present invention relates to a nitride-based phosphor that absorbs at least a part of light emitted by the semiconductor light-emitting element and emits light having a wavelength different from that of the absorbed light, a manufacturing method thereof, and a light-emitting device using the phosphor.

  A light-emitting device using a semiconductor element as a light-emitting element emits light with a small color, high power efficiency, and vivid colors. In addition, a light emitting element which is a semiconductor element does not have a concern about a broken ball. Furthermore, the initial drive characteristics are excellent, and it is characterized by being strong against vibration and ON / OFF lighting repetition. Because of such excellent characteristics, light-emitting devices using semiconductor light-emitting elements such as light-emitting diodes (LEDs) and laser diodes (LDs) are used as various light sources.

  In particular, a high-luminance blue light-emitting LED using a GaN-based compound semiconductor has been developed, and a white light-emitting device has been realized by utilizing the luminance. In this white light emitting device, a light emitting element that emits blue light is covered with a resin containing a fluorescent material that emits yellow green light to obtain white light.

A part of the light from the light-emitting element is wavelength-converted by the phosphor, and the wavelength-converted light and the light from the light-emitting element that is not wavelength-converted are mixed and emitted to emit light that is different from the light from the light-emitting element A light emitting device has been developed. For example, a blue light-emitting diode (Light Emitting Diode, hereinafter also referred to as “LED”) using an InGaN-based material as a light-emitting element is used, and a composition of (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce is formed on the surface thereof. A white LED light-emitting device coated with a fluorescent member made of a transparent material such as an epoxy resin containing a YAG: Ce-based phosphor represented by the formula has been put into practical use. The emission color of the white LED light emitting device is obtained by the principle of light color mixing. The blue light emitted from the light emitting element is incident on the fluorescent member, and after being repeatedly absorbed and scattered in the layer, is emitted to the outside. On the other hand, the blue light absorbed by the phosphor serves as an excitation source and emits yellow or yellow-green light. This yellow light and blue light are mixed and appear as white to the human eye. An LED light emitting device using such an LED emits light with a small size, high power efficiency, and vivid colors. In addition, since the LED is a semiconductor element, there is no fear of a broken ball. In addition, it has excellent initial drive characteristics and is strong against repeated ON / OFF lighting. Since it has such excellent characteristics, LED light-emitting devices are used as various light sources.

  However, since the light emitting device that emits white light does not easily emit light on the long wavelength side in the visible light region, the light emitting device has a slightly bluish white light that lacks a red component. In particular, warm red light emitting devices that are slightly reddish are required in store display lighting and medical site lighting. In addition, since light emitting elements generally have a longer life than human light bulbs and are easy on human eyes, a white light emitting device close to the color of a light bulb is strongly demanded.

  Usually, when redness increases, the light emission characteristics of the light emitting device deteriorate. The color perceived by human eyes produces a sense of brightness in electromagnetic waves having a wavelength range of 380 to 780 nm. One of the indexes representing this is the visibility characteristic. The visibility characteristic has a mountain shape, and has a peak at 550 nm. When the same electromagnetic wave enters the red component region near 580-680 nm and 550 nm, the red component wavelength region feels darker. Therefore, in order to feel the same level of brightness as the green and blue regions, the red region requires high-density electromagnetic wave incidence.

  Further, the conventional red light-emitting phosphor has a problem that the efficiency and durability due to excitation of blue light from the near ultraviolet are not sufficient, and the light emission efficiency is drastically lowered at higher temperatures.

In particular, the nitride-based phosphor is deteriorated when moisture is present, and therefore it is necessary to provide moisture resistance to improve the durability. For this reason, it is conceivable to apply a moisture-proof coating on the surface of the phosphor. On the other hand, it is necessary to uniformly disperse the phosphor around the light emitting element in order to convert the wavelength of the light of the light emitting element by the phosphor and to extract the uniform light to the outside by color mixing. However, the phosphor having improved moisture resistance by coating as described above has insufficient fluidity, poor dispersibility, and condensation, resulting in non-uniform external light emission.
JP 2002-223008 A

  The present invention has been made to solve such problems. A main object of the present invention is to provide a light-emitting device, a phosphor for a light-emitting element, and a method for manufacturing the same, which are excellent in durability and can obtain high-quality output light.

In order to achieve the above object, a light-emitting device according to the first aspect of the present invention includes a light-emitting element and a periphery of the light-emitting element so as to absorb at least a part of light emitted from the light-emitting element and convert it to a different wavelength. The phosphor is made of a nitride-based fluorescent material or an oxynitride-based fluorescent material containing nitrogen, and the surface of the phosphor is different by two or more. It has a coating layer containing the compound. Thereby, it can coat | cover with a different compound and can suppress deterioration of a fluorescent substance.
With this configuration, the phosphor of nitride or oxynitride is prevented from being oxidized, and deterioration of the phosphor is suppressed to enable stable use over a long period of time.

  In addition, a light emitting device according to the second aspect of the present invention includes a light emitting device and a phosphor disposed around the light emitting device so as to absorb and convert at least part of light emitted from the light emitting device to a different wavelength. The phosphor is made of a nitride-based fluorescent material or an oxynitride-based fluorescent material containing nitrogen, and at least 40% or more of the surface area of the phosphor is two or more different compounds It is covered with. Thereby, deterioration of a fluorescent substance can be suppressed. Furthermore, in order to enhance the prevention of deterioration, at least 65% of the surface area of the phosphor is preferable, and at least 80% of the surface area of the phosphor is preferably coated with a predetermined compound.

  Furthermore, in the light emitting device according to the third aspect of the present invention, the coating layer has a multilayer structure of two or more layers.

  Furthermore, in the light emitting device according to the fourth aspect of the present invention, one of the two or more different compounds is a metal oxide, and the other is an oxide that is stable with respect to the metal oxide.

  Furthermore, in the light emitting device according to the fifth aspect of the present invention, at least one of the two or more different compounds is a metal oxide such as magnesium oxide, aluminum oxide, boron oxide, yttrium oxide, titanium oxide, silicon oxide, Zirconium oxide, zinc oxide, or a composite oxide composed of a combination of two or more of these elements is preferable.

  Furthermore, in the light emitting device according to the sixth aspect of the present invention, at least one of the two or more different compounds is a phosphate, calcium phosphate, magnesium phosphate, strontium phosphate, barium phosphate, zinc phosphate, phosphorus Aluminum phosphate, gallium phosphate, indium phosphate, boron phosphate, bismuth phosphate, yttrium phosphate, lanthanum phosphate, cerium phosphate, or a composite phosphate composed of a combination of two or more of these elements. Accordingly, the coating layer prevents oxidation of the nitride or oxynitride phosphor, and suppresses deterioration of the phosphor, thereby enabling stable use over a long period of time.

  Furthermore, in the light emitting device according to the seventh aspect of the present invention, the phosphor is contained in a translucent resin and disposed around the light emitting element. With this configuration, deterioration of the phosphor due to moisture or oxidation at the interface with the translucent resin can be suppressed, and the phosphor can be used with high reliability.

  Furthermore, in the light emitting device according to the eighth aspect of the present invention, the light emitting element is a light emitting diode.

  Furthermore, the phosphor for a light-emitting element according to the ninth aspect of the present invention is a phosphor for a light-emitting element for absorbing at least a part of light emitted from the light-emitting element and converting it to a different wavelength. Is made of a nitride-based fluorescent material or an oxynitride-based fluorescent material containing nitrogen, and the surface of the phosphor has a coating layer containing two or more different compounds.

  Furthermore, the phosphor for a light emitting device according to the tenth aspect of the present invention is a phosphor for a light emitting device for absorbing at least a part of light emitted from the light emitting device and converting it to a different wavelength. Is made of a nitride-based fluorescent material or an oxynitride-based fluorescent material containing nitrogen, and at least 40% or more of the surface area of the phosphor is coated with two or more different compounds.

  Furthermore, in the phosphor for a light emitting device according to the eleventh aspect of the present invention, the coated compound is present in different and different coating layers.

  Furthermore, in the phosphor for a light emitting device according to the twelfth aspect of the present invention, the phosphor is LMM: R, LJMN: R, or LMMON. : R (L contains one or more selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn, and M is selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, Hf) 1 or more types, J contains 1 or more types selected from the group consisting of B, Al, Ga, In, Sc, and Y, N is nitrogen, O is oxygen, and R is a rare earth element). It is a nitride-based or oxynitride-based phosphor represented.

Furthermore, the thirteenth phosphor for a light emitting device according to the aspect of the present invention, the _{phosphor, L x M y N {(} 2/3) x + (4/3) y}: R, L x J w _{M y N {(2/3) x} + w + (4/3) y}, or _{L x M y O z N {} (2/3) x + (4/3) y- (2/3) z}: R (L contains one or more selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn, and M is selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, Hf 1 And J contains one or more selected from the group consisting of B, Al, Ga, In, Sc, and Y, N is nitrogen, O is oxygen, and R is a rare earth element). And has a crystal structure.

Furthermore, the 14th phosphor for a light emitting device according to the aspect of the present invention, the _{phosphor, L x M y N {(} 2/3) x + (4/3) y}: R, L x J w _{M y N {(2/3) x} + w + (4/3) y}, or _{L x M y O z N {} (2/3) x + (4/3) y- (2/3) z}: R (0.5 ≦ x ≦ 3, 0.5 ≦ y ≦ 9.0, 0.5 ≦ w ≦ 5, 0 ≦ z ≦ 3; L is a group consisting of Be, Mg, Ca, Sr, Ba, Zn One or more selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf, and J includes B, Al, Ga, In, Sc, 1 or more selected from the group consisting of Y, N is nitrogen, O is oxygen, and R is a rare earth element), and has a crystal structure.

Furthermore, the 15 phosphor for a light emitting device according to the aspect of the present invention, the _{phosphor, L x M y N {(} 2/3) x + (4/3) y}: R, L x J w _{M y N {(2/3) x} + w + (4/3) y}, or _{L x M y O z N {} (2/3) x + (4/3) y- (2/3) z}: R (x = 2, 4.5 ≦ y ≦ 6.0, 0.01 <z <1.5, or x = 1, 6.5 ≦ y ≦ 7.5, 0.01 <z <1.5 Or x = 1, 1.5 ≦ y ≦ 2.5, 1.5 ≦ z ≦ 2.5; L contains one or more selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn M includes one or more selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf, and J is selected from the group consisting of B, Al, Ga, In, Sc, and Y. It contains a seed or more, N is nitrogen, O is oxygen, and R is a rare earth element) and has a crystal structure.

  Furthermore, in the phosphor for light emitting device according to the sixteenth aspect of the present invention, the crystal structure of the phosphor is monoclinic or orthorhombic.

  Furthermore, in the phosphor for light emitting element according to the seventeenth aspect of the present invention, the phosphor contains a B element.

  Furthermore, in the phosphor for light emitting element according to the eighteenth aspect of the present invention, the phosphor is a phosphor for light emitting diode.

  Furthermore, the method for manufacturing a phosphor for a light-emitting element according to the nineteenth aspect of the present invention is a method for manufacturing a phosphor for a light-emitting element for absorbing at least a part of light emitted from the light-emitting element and converting it to a different wavelength. A step of bringing a coating containing solution for forming a coating layer containing two or more different compounds into contact with the surface of a phosphor made of a nitride fluorescent material containing nitrogen or an oxynitride fluorescent material; and And a step of heat-treating the treated phosphor.

  Furthermore, in the method for manufacturing a phosphor for a light-emitting element according to the twentieth aspect of the present invention, the heat treatment is performed at 200 ° C. or higher in an oxygen-free atmosphere. Thereby, the phosphor treated with the phosphorus-containing compound can be modified to make the phosphor more dense and further improve the durability.

  Furthermore, in the method for manufacturing a phosphor for a light-emitting element according to the twenty-first aspect of the present invention, the phosphor for a light-emitting element is a phosphor for a light-emitting diode.

  As described above, the light-emitting device, the phosphor for a light-emitting element, and the manufacturing method thereof of the present invention are used for a light-emitting element such as an LED by covering the surface of the phosphor with a compound composed of two or more elements. In this case, deterioration due to oxidation caused by heat and moisture of the phosphor, or deterioration of the resin or the like due to components contained in the phosphor can be improved, and deterioration of light emission characteristics can be prevented. In particular, by using a composite layer in which two or more kinds of elements are combined, different functions can be provided for each layer, and the deterioration preventing effect can be increased to a single layer or more. Moreover, even if it does not become a complete layer, deterioration can be suppressed by adhering and covering a predetermined compound on 40% or more, more preferably 65% or more of the surface area of the phosphor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a light emitting device, a phosphor for a light emitting element, and a manufacturing method thereof for embodying the technical idea of the present invention. The present invention is for a light emitting device and a light emitting element. The phosphor and its manufacturing method are not specified as follows. Further, the present specification by no means specifies the members shown in the claims to the members of the embodiments. 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.

In the following embodiments, it is possible to completely cover the surface of the phosphor, but there may be a case where a part of the surface of the phosphor is not coated. Therefore, the “coating layer” will be described below as including not only a case where the surface of the phosphor is completely covered but also a case where a predetermined compound is adhered to 40% or more and less than 100% of the surface area of the phosphor. To do.
(Light emitting device)

  A light-emitting device according to an embodiment of the present invention is shown in FIG. 1A is a plan view of the light emitting device, and FIG. 1B is a schematic cross-sectional view. In the semiconductor light emitting device, a semiconductor light emitting element 2 is attached to a recess in the center of the package 1, and the electrode of the semiconductor light emitting element 2 and the electrode of the package 1 are connected by a wire 4. A predetermined amount of a binder in which a phosphor is dispersed is sealed in the central recess of the package 1 to form a phosphor layer 3. A part of light emitted from the semiconductor light emitting element 2 is transmitted through the phosphor layer 3, and part of the light is converted into light having a longer wavelength by the phosphor layer 3, and the transmitted light and the converted light are combined to emit light from the semiconductor light emitting device. Become. By adjusting the phosphor layer 3, semiconductor light emitting devices of various chromaticities including white are formed.

  FIG. 2 shows a schematic cross-sectional view of the light emitting device according to Embodiment 2 of the present invention. In the light emitting device shown in this figure, the phosphor layer 3B is not filled in the entire recess of the package 1B, and is arranged so as to cover only the periphery of the semiconductor light emitting element 2B. As a result, the phosphors are arranged almost uniformly around the semiconductor light emitting element 2B to reduce wavelength conversion unevenness and suppress light distribution chromaticity unevenness. The electrode of the semiconductor light emitting element 2B and the electrode of the package 1B are connected by a wire 4B as in FIG.

Furthermore, FIG. 3 shows a schematic cross-sectional view of a light emitting device according to Embodiment 3 of the present invention. The light-emitting device shown in this figure includes a light-emitting element 10, a nitride-based phosphor, and a fluorescent member 11 made of a translucent material containing the nitride-based phosphor. The light-emitting element 10 shown in this figure is an LED, and is mounted by die-bonding at a substantially central portion of a cup disposed on the mount lead 13a. The electrode formed on the light emitting element 10 is conductively connected to the mount lead 13 a and the inner lead 13 b of the lead frame 13 by the conductive wire 14. The light emitting element 10 absorbs at least a part of the light emitted and contains a nitride fluorescent material that emits light having a wavelength different from the absorbed light and an N element, and covers the nitride fluorescent material. A fluorescent member 11 containing a nitride-based phosphor composed of a coating material in a translucent material is placed in a cup on which the light emitting element 10 is placed. The lead frame 13 in which the light emitting element 10 and the fluorescent member 11 are arranged in this manner is molded by the molding member 15 for the purpose of protecting the LED chip and the fluorescent material from external stress, moisture, dust, and the like, thereby forming a light emitting device. The light emitting element 10 can be the same type as the light emitting element used in the first embodiment described above.
(Light emitting element)

  In this specification, the light emitting element includes not only a semiconductor light emitting element such as an LED and an LD, but also an element for obtaining light emission by vacuum discharge and light emission from thermoluminescence. For example, ultraviolet light by vacuum discharge can be used as the light emitting element. In the first embodiment of the present invention, a light-emitting element having a wavelength of 550 nm or less, preferably 460 nm or less, more preferably 410 nm or less is used as the light-emitting element. For example, an ultraviolet LED that emits light having a wavelength of 250 nm to 365 nm as ultraviolet light or a high-pressure mercury lamp having a wavelength of 253.7 nm can be used. In particular, as described later, in the first embodiment of the present invention, the durability of the phosphor is improved, so that there is an advantage that it can be used for a power-based light emitting device with high output.

Various nitride semiconductors can be used as each semiconductor layer constituting the LED or LD. Specifically, the organic metal chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE) or the like on the substrate _{In X Al Y Ga 1-XY} N (0 ≦ X, 0 ≦ Y, X + Y ≦ 1) A semiconductor in which a plurality of such semiconductors are formed is preferably used. In addition, the layer structure includes a homo structure having a MIS junction, a PIN junction or a PN junction, a hetero structure, or a double hetero structure. Each layer may have a superlattice structure, or may have a single quantum well structure or a multiple quantum well structure in which an active layer is formed in a thin film in which a quantum effect is generated.

The LED is generally formed by growing each semiconductor layer on a specific substrate, but when an insulating substrate such as sapphire is used as the substrate and the insulating substrate is not finally removed, Usually, both the p-side electrode and the n-side electrode are formed on the same surface side on the semiconductor layer. In this case, face-up mounting, that is, it is possible to arrange the semiconductor layer side on the viewing side and take out emitted light from the semiconductor layer side, or face-down mounting as shown in FIG. That is, it is also possible to arrange the substrate side on the viewing side and take out the emitted light from the substrate side. Of course, it is also possible to mount the face up or face down after finally removing the substrate. The substrate is not limited to sapphire, and a known member such as spinel, SiC, GaN, or GaAs can be used.
(Face-down mounting)

  Face-down mounting is also called flip-chip mounting, and the electrode forming surface of a semiconductor light-emitting element chip on which positive and negative electrodes are provided on the same side is made to face a conductive pattern such as a support substrate, and through a conductive member such as a bump. Mounting method. Therefore, the flip-chip light emitting element has electrodes formed on the surface connected to the support substrate. FIG. 4 shows a schematic cross-sectional view of a package 1C in which the semiconductor light emitting element 2C is flip-chip mounted. In this example, reference numeral 1C denotes a submount member. In a state where the semiconductor light emitting element 2C is mounted face-down on the lead electrode of the submount member, the upper surface and the side surface of the semiconductor light emitting element 2C include a fluorescent material containing a fluorescent material. It is covered with a phosphor layer 3C which is a resin. In the semiconductor light emitting element 2C, the lead electrode provided on the submount member is electrically connected to the support substrate directly with a wire or via a bump. The submount member can also have a function of a protective element for protecting the semiconductor light emitting element from forward and reverse overvoltages. Further, the semiconductor element can be directly mounted on the support substrate without using the submount member.

  Next, an example in which a Group III nitride semiconductor light emitting device is used as the light emitting device will be described. The light emitting element is, for example, a first n-type GaN layer in which Si is undoped or has a low Si concentration via a GaN buffer layer on a sapphire substrate, Si is doped, or the Si concentration is higher than that in the first n-type GaN layer. An n-type contact layer made of n-type GaN, a second GaN layer having an undoped or Si concentration lower than that of the n-type contact layer, a light emitting layer having a multiple quantum well structure (GaN barrier layer / InGaN well layer quantum well structure), Mg A p-type cladding layer made of p-type GaN doped with p-type GaN and a p-type contact layer made of p-type GaN doped with Mg are sequentially stacked, and an electrode is formed as follows Has been. However, it goes without saying that a light-emitting element different from this configuration can also be used. The p ohmic electrode is formed on almost the entire surface of the p-type contact layer, and the p pad electrode is formed on a part of the p ohmic electrode. The n-electrode is formed on the exposed portion by removing the first GaN layer from the p-type contact layer by etching to expose a part of the n-type contact layer. In the first embodiment, the light emitting layer having a multiple quantum well structure is used. However, the present invention is not limited to this. For example, a single quantum well structure or a multiple quantum well structure using InGaN may be used. Alternatively, GaN doped with Si, Zn or the like may be used.

The light emitting layer of the light emitting element can change the main light emission peak in the range of 420 nm to 490 nm by changing the In content. The emission wavelength is not limited to the above range, and those having an emission wavelength of 360 to 550 nm can be used. In particular, when the light-emitting device of the present invention is applied to an ultraviolet LED light-emitting device, the absorption conversion efficiency of excitation light can be increased, and transmitted ultraviolet light can be reduced.
(Phosphor)

  The phosphor used in the above embodiment converts visible light or ultraviolet light emitted from the light emitting element into another emission wavelength. A phosphor is used as a wavelength conversion material that emits light having a wavelength longer than the wavelength of the absorbed light, and desired light can be emitted to the outside by color mixture of light emitted from the light emitting element and converted light of the phosphor. The phosphor has translucency, and emits light when excited by light emitted from the semiconductor light emitting layer of the LED, for example. Preferred phosphors include YAG-based with europium, zinc sulfide co-attached with silver and aluminum, nitrides such as alkaline-earth silicon nitride phosphor, alkaline-earth silicon oxynitride phosphor, etc. Oxynitride phosphors can be used. Further, a phosphor that generates light of a predetermined color when excited by ultraviolet light may be used.

  Nitride-based phosphors selectively contain oxygen, for example, LMN: R, LJMN: R, or LMON: R (L is Be, Mg). , Ca, Sr, Ba, Zn, one or more selected from the group consisting of Zn, M is one or more selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, Hf, J is B 1 or more selected from the group consisting of Al, Ga, In, Sc, and Y, N is nitrogen, O is oxygen, and R is a rare earth element).

The phosphor includes N, O selectively, and at least one element selected from Be, Mg, Ca, Sr, Ba, and Zn, and C, Si, Ge, Sn, Ti, Zr. And a nitride-based phosphor containing at least one element selected from Hf and activated with Eu and / or rare earth elements is preferably used. Further, the phosphor may contain B, Al, Ga, In, Sc, and Y. That is, it is a crystalline phosphor in which the constituent elements are simply represented by LMN: R, LJMN: R, or LMON: R. The crystal structures are, for example, Ca ₂ Si ₅ N ₈ is monoclinic, Sr ₂ Si ₅ N ₈ , (Sr _0.5 Ca _0.5 ) ₂ Sr ₅ N ₈ is orthorhombic, and Ba ₂ Si ₅ N ₈ is monoclinic. Take. CaAlSiN ₃ : Eu is orthorhombic, BaSi ₂ O ₂ N ₂ : Eu, SrSi ₂ O ₂ N ₂ : Eu, and CaSi ₂ O ₂ N ₂ : Eu is orthorhombic.

More specifically, generally _{L x M y N {(2/3} ) x + (4/3) y}: R, L x J w M y N {(2/3) x + w + (4/3) _y}: R or _{L x M y O z N,} {(2/3) x + (4/3) y- (2/3) z}: is represented by R, L is be, Mg, Ca, Sr, One or more selected from the group consisting of Ba and Zn; M is one or more selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf; and J is B, Al, Ga, It is at least one selected from the group consisting of In and Sc, N is nitrogen, O is oxygen, R is a phosphor represented by a rare earth element, and in addition to Eu, Mg, B, Mn, Cr, Ni, etc. may be included.

  Further, the phosphor is crystalline in 60% or more, preferably 80% or more in the composition. In general, it is desirable that x = 2, y = 5 or x = 1, y = 7, or x = 1, y = 1, w = 1 or x = 1, y = 2, z = 2. Any value can be used.

  Among trace amounts of additives, B and the like can increase the crystallinity without deteriorating the light emission characteristics, and Mn, Cu and the like have the same effect. La, Pr, etc. also have the effect of improving the light emission characteristics. In addition, Mg, Cr, Ni and the like have an effect of shortening afterglow and are used as appropriate. In addition, even elements that are not shown in the present specification can be added without significantly reducing the luminance if they are about 10 to 1000 ppm.

  The rare earth element contained in R preferably contains one or more of Y, La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, and Lu, but Sc, Sm, Tm, Yb may be contained. In addition to the above elements, B, Mn, and the like have an effect of improving luminance and may be contained. These rare earth elements are mixed in the raw material in the form of oxides, imides, amides, etc. in addition to simple substances. Rare earth elements mainly have a stable trivalent electron configuration, but Yb, Sm, etc. also have a bivalent configuration, and Ce, Pr, Tb, etc. also have a tetravalent electron configuration. When the rare earth element of the oxide is used, the involvement of oxygen affects the light emission characteristics of the phosphor. In other words, the emission luminance may be reduced by containing oxygen. However, when Mn is used, the particle size can be increased by the flux effect of Mn and O, and the emission luminance can be improved.

Europium Eu, which is a rare earth element, is preferably used as the emission center. Europium mainly has bivalent and trivalent energy levels. The phosphor of the present invention uses Eu ²⁺ as an activator for the base alkaline earth metal silicon nitride. Eu ²⁺ is easily oxidized and is usually used in the composition of trivalent Eu ₂ O ₃ . However, in this Eu ₂ O ₃ , O is greatly involved and it is difficult to obtain a good phosphor. For this reason, it is more preferable to use a material obtained by removing O from Eu ₂ O ₃ . For example, it is preferable to use europium alone or europium nitride. However, this is not the case when Mn is added.

Specific examples of basic constituent elements include Ca ₂ Si ₅ N ₈ : Eu, Eu, B added, Sr ₂ Si ₅ N ₈ : Eu, (Sr _0.5 Ca _0.5 ) ₂ Sr ₅ N ₈ : Eu Ca ₂ Si ₅ O _0.1 N _7.9 : Eu, Sr ₂ Si ₅ O _0.1 N _7.9 : Eu, (Ca _a Sr _1-a ) ₂ Si ₅ O _0.1 N _7.9 : Eu, BaSi ₂ O ₂ N ₂ : Eu, CaSi ₂ O ₂ N ₂ : Eu, and Ca ₂ Si ₅ O _0.3 N _7.8 : Eu, rare earth added, Sr ₂ Si ₅ O _0.3 N _7.8 : Eu, (Ca _a Sr _1-a ) ₂ Si ₅ O _0.1 N _7.9 : Eu, CaAlSiN ₃ : Eu, SrAlSiN ₃ : Eu, (Ca _0.5 Sr _0.5 ) AlSiN ₃ : Eu, CaAlSiB _x N _{3 + x} : Eu, SrAlSiB _x N _{3 + x} : Eu, (Ca _0.5 Sr _{0.5) AlSiB x N 3 + x} : there is Eu and the like.

Further, Sr ₂ Si ₅ N ₈ : Eu, Pr, Ba ₂ Si ₅ N ₈ : Eu, Pr, Mg ₂ Si ₅ N ₈ : Eu, Pr, Zn ₂ Si ₅ N ₈ : Eu, Pr, SrSi ₇ N ₁₀ : _{Eu, Pr, BaSi 7 N 10} : Eu, Ce, MgSi 7 N 10: Eu, Ce, ZnSi 7 N 10: Eu, Ce, Sr 2 Ge 5 N 8: Eu, Ce, Ba 2 Ge 5 N 8: Eu _{, Pr, Mg 2 Ge 5 N} 8: Eu, Pr, Zn 2 Ge 5 N 8: Eu, Pr, SrGe 7 N 10: Eu, Ce, BaGe 7 N 10: Eu, Pr, MgGe 7 N 10: Eu, _{Pr, ZnGe 7 N 10: Eu} , Ce, Sr 1.8 Ca 0.2 Si 5 N 8: Eu, Pr, Ba 1.8 Ca 0.2 Si 5 N 8: Eu, Ce, Mg 1.8 Ca 0.2 Si 5 N 8: Eu, Pr, _{Zn 1.8 Ca 0.2 Si 5 N 8} : Eu, Ce, Sr 0.8 Ca 0.2 Si 7 N 10: Eu, L _{, Ba 0.8 Ca 0.2 Si 7 N} 10: Eu, La, Mg 0.8 Ca 0.2 Si 7 N 10: Eu, Nd, Zn 0.8 Ca 0.2 Si 7 N 10: Eu, Nd, Sr 0.8 Ca 0.2 Ge 7 N 10: Eu , Tb, Ba _0.8 Ca _0.2 Ge ₇ N ₁₀ : Eu, Tb, Mg _0.8 Ca _0.2 Ge ₇ N ₁₀ : Eu, Pr, Zn _0.8 Ca _0.2 Ge ₇ N ₁₀ : Eu, Pr, Sr _0.8 Ca _0.2 Si ₆ GeN ₁₀ : Eu, Pr, Ba _0.8 Ca _0.2 Si ₆ GeN ₁₀ : Eu, Pr, Mg _0.8 Ca _0.2 Si ₆ GeN ₁₀ : Eu, Y, Zn _0.8 Ca _0.2 Si ₆ GeN ₁₀ : Eu, Y, Sr ₂ Si ₅ N ₈ : Pr, Ba ₂ Si ₅ N ₈ : Pr, Sr ₂ Si ₅ N ₈ : Tb, BaGe ₇ N ₁₀ : Ce and the like can be produced, but are not limited thereto. Similarly, it is naturally conceivable that the phosphors described by these general formulas appropriately contain suitable elements such as the third component, the fourth component, and the fifth component as desired.

  These fluorescent materials can use phosphors having emission spectra in yellow, red, green, and blue by the excitation light of the light emitting element 110, and can also be used in yellow, green, blue green, orange, etc., which are intermediate colors thereof. A phosphor having an emission spectrum can also be used. By using these phosphors in various combinations, light emitting devices having various emission colors can be manufactured.

For example, CaSi ₂ O ₂ N ₂ : Eu or SrSi ₂ O ₂ N ₂ : Eu that emits light from green to yellow, and (Sr, Ca) ₅ (PO ₄ ) ₃ Cl: Eu that emits blue light as a phosphor. By using a phosphor composed of (Ca, Sr) ₂ Si ₅ N ₈ : Eu that emits red light, a light emitting device that emits white light with good color rendering can be provided. This uses the three primary colors of red, blue, and green, so the desired white light can be achieved simply by changing the blend ratio of the first phosphor and the second phosphor. Can do.

  After the nitride-based phosphor or the oxynitride-based phosphor compound is formed, the powder is recovered by a general separation method. The collected phosphor powder is dried to evaporate moisture. Although drying can be performed at room temperature, in order to perform more reliable drying, it is preferable to dry by applying heat to such an extent that the nitride phosphor or oxynitride phosphor is not oxidized in the atmosphere. Conventionally, the drying process is performed in the air, and the phosphor itself may be oxidized and deteriorated depending on temperature conditions. Therefore, in this embodiment, in order to prevent deterioration due to oxidation, heat treatment (annealing) is performed in a reducing atmosphere containing no oxygen such as a nitrogen atmosphere. Thereby, the state of the coating layer can be modified. The temperature of the heat treatment is preferably 200 ° C to 500 ° C, more preferably 250 ° C to 400 ° C, and most preferably around 300 ° C. Thereby, moisture can be reliably removed from the phosphor, and it can be avoided that the phosphor is oxidized and deteriorated during the heat treatment.

  The average particle diameter of the phosphor is 3 μm or more, preferably 5 μm to 15 μm. Fine phosphors are classified and removed by means of classification or the like, and particles having a particle size of 2 μm or less are made to have a volume distribution of 10% or less. As a result, the luminance of emitted light can be improved, and the chromaticity variation in the alignment direction of light can be reduced by reducing the number of particles having a particle size of 2 μm or less.

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, and then a constant pressure of dry air is flowed to read the specific surface area 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 invention is preferably in the range of 2 μm to 8 μm, and it is preferable that the phosphor having this average particle size value is contained frequently. Further, the particle size distribution is preferably distributed in a narrow range, and it is particularly preferable that the number of fine particles having a particle size of 2 μm or less is small. In this way, 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.
(Fluorescent resin)

  A wavelength conversion layer is formed by mixing the phosphor as a wavelength conversion member into the fluorescence-containing resin. A thermosetting resin can be used as the fluorescent resin. It is preferable that the phosphor is mixed in the fluorescence-containing resin at a substantially uniform ratio. However, it can also mix | blend so that a fluorescent material may be unevenly distributed. For example, the phosphor-containing resin is unevenly distributed so that a large amount of phosphor is contained on the outer surface side, and is separated from the contact surface between the light-emitting element and the phosphor-containing resin, thereby making it difficult for heat generated in the light-emitting element to be transmitted to the phosphor. Deterioration of the phosphor can be suppressed. As the fluorescent-containing resin, it is preferable to use a silicone resin composition, a modified silicone resin composition, etc., but an insulating resin composition having translucency such as an epoxy resin composition, a modified epoxy resin composition, an acrylic resin composition, etc. Can also be used. In addition, a pigment, a diffusing agent, or the like can be mixed in the fluorescent-containing resin.

The fluorescent-containing resin is preferably soft even after curing. Before curing, the fluorescent-containing resin is spread around the light-emitting element, and the fluorescent-containing resin is infiltrated into a gap portion other than the portion where the light-emitting element to be face-down mounted and the lead electrode are electrically connected. A low liquid is preferable. Moreover, it is preferable that fluorescence containing resin has adhesiveness. By giving adhesiveness to the fluorescence-containing resin, the adhesion between the light emitting element and the pedestal can be enhanced. The adhesiveness includes not only those exhibiting adhesiveness at room temperature but also those that are bonded by applying predetermined heat and pressure to the fluorescent resin. In addition, the fluorescent-containing resin can be applied with temperature or pressure or dried in order to increase the fixing strength.
(Diffusion agent)

  Furthermore, in addition to the phosphor, a diffusing agent may be contained in the fluorescence-containing resin. As a specific diffusing agent, barium titanate, titanium oxide, aluminum oxide, silicon oxide or the like is preferably used. As a result, a light emitting device having good directivity can be obtained.

Here, in this specification, the diffusing agent refers to those having a center particle diameter of 1 nm or more and less than 5 μm. A diffusing agent having a particle size of 1 μm or more and less than 5 μm can be preferably used because it diffuses light from the light emitting element and the phosphor well and can suppress color unevenness that tends to occur when a fluorescent material having a large particle size is used. In addition, the half width of the emission spectrum can be narrowed, and a light emitting device with high color purity can be obtained. On the other hand, a diffusing agent having a wavelength of 1 nm or more and less than 1 μm has a low interference effect on the light wavelength from the light emitting element, but has a high transparency and can increase the resin viscosity without reducing the luminous intensity.
(Filler)

Furthermore, you may contain a filler other than fluorescent substance in fluorescent containing resin. As a specific material, the same material as the diffusing agent can be used. However, the diffusing agent and the filler have different center particle sizes. In this specification, the center particle size of the filler is preferably 5 μm or more and 100 μm or less. When the filler having such a particle size is contained in the translucent resin, the chromaticity variation of the light emitting device is improved by the light scattering action, and the thermal shock resistance of the translucent resin can be enhanced. As a result, a highly reliable light-emitting device that can prevent disconnection of the wire that electrically connects the light-emitting element and the external electrode, and peeling between the bottom surface of the light-emitting element and the bottom surface of the recess of the package, even when used at high temperatures. And can. Furthermore, the fluidity of the resin can be adjusted to be constant for a long time, a sealing member can be formed in a desired place, and mass production can be performed with a high yield.
(Multilayer coating)

  Nitride-based fluorescent materials and oxynitride-based fluorescent materials have a special characteristic that they easily deteriorate under specific conditions. In particular, the nitride-based phosphor is deteriorated when moisture is present, and therefore it is necessary to provide moisture resistance to improve the durability. On the other hand, it is necessary to uniformly disperse the phosphor around the light emitting element in order to convert the wavelength of the light from the light emitting element by the phosphor and extract the uniform light to the outside by color mixing. However, the phosphor having improved moisture resistance by coating as described above has insufficient fluidity and may be condensed to cause non-uniform external light emission.

  As a result of studying such a configuration that achieves both moisture resistance and fluidity, the present inventors have coated single particles of nitride phosphor particles with a compound composed of two or more different elements. It was found that a nitride-based phosphor and an oxynitride-based phosphor having improved durability, particularly properties in a thermal oxidation atmosphere, can be obtained as compared with a coating layer composed of a single layer. FIG. 5 shows an example in which a composite coating layer is formed on the surface of the phosphor by multilayer coating. As described above, the phosphor is coated with the multilayer film of the first layer 51 on the surface of the phosphor 50 and the second layer 52 further coated on the first layer 51, and the function of improving moisture resistance and fluidity on each layer. By providing these, it is possible to achieve both of these characteristics and have ideal characteristics as a phosphor used in combination with a light emitting element. In particular, when an LED is used as the light-emitting element, this characteristic that can suppress deterioration at the interface with the LED is extremely effective because it also affects the light emission efficiency. Furthermore, handling is improved by making the coating on the phosphor surface a multi-layer structure, and an effect of facilitating manufacture and handling can be obtained. In addition, heat resistance was improved by multilayer coating. Note that the first layer and the second layer do not need to be clearly distinguished as layers, and need only have a property of maintaining moisture resistance and fluidity even when the interface is unclear.

  The compound that coats the phosphor is a composite composed of metal oxides magnesium oxide, aluminum oxide, boron oxide, yttrium oxide, titanium oxide, silicon oxide, zirconium oxide, zinc oxide, or a combination of two or more of these elements. An oxide can be suitably used. By coating these metal oxides, the durability of the phosphor in a thermal oxidation atmosphere can be improved.

  Moreover, the compound which coat | covers fluorescent substance on a metal oxide is a phosphate, calcium phosphate, magnesium phosphate, strontium phosphate, barium phosphate, zinc phosphate, aluminum phosphate other than a metal oxide, A composite phosphate composed of gallium phosphate, indium phosphate, boron phosphate, bismuth phosphate, yttrium phosphate, lanthanum phosphate, cerium phosphate, or a combination of two or more of these elements can also be used. For example, when silicon oxide is coated, an aqueous solution of potassium silicate, sodium silicate or the like, or insoluble fine particle silicon oxide can be used. It is also possible to use a metal organic compound such as tetramethoxysilane or tetraethoxysilane. By coating with these, uniform dispersion can be achieved without reducing the fluidity of the phosphor. In addition, it is preferable to locate a compound that exhibits a function of improving fluidity on the surface of the phosphor, and a compound having a function of improving moisture resistance on the inner surface side. Thereby, the fluidity of the coating compound can be maximized.

  As a method for coating these compounds, conventional known methods such as CVD, wet method, and dry method can be appropriately used. In particular, the CVD method is preferable from the viewpoint of uniform film quality.

For the wet coating of the nitride or oxynitride phosphor, an aqueous solution or an organic solvent is appropriately selected according to the raw material used. When a coating layer composed of two or more elements is formed in one coating layer, two or more types are selected from the above compounds, and the coating step is performed in a solution. In this case, the coating can be performed by continuous processing, or can be separated once after each coating processing and then performed again. Similarly, in the case of a film formed by CVD or a dry method, it is also possible to perform a continuous coating process, and after performing each coating process, the film is separated and then coated again.
(Processing liquid)

As a treatment liquid used in the wet treatment, the obtained phosphor is suspended in water, and then an aqueous solution such as potassium silicate or sodium silicate is added to obtain a treatment liquid. Furthermore, a composite coating layer composed of two elements of silicon and magnesium is formed on the phosphor particles by adjusting the pH by adding an aqueous solution of a magnesium compound or the like and using aqueous ammonia or the like as necessary. . The phosphor thus coated is then separated and moisture is removed in a drying process.
(Drying process)

  After the nitride-based phosphor or the oxynitride-based phosphor is coated by a wet method, the powdered phosphor is recovered by a general separation method. The collected phosphor powder may be dried at room temperature in order to evaporate moisture, etc., but it should be dried by heating to the extent that the nitride phosphor or oxynitride phosphor is not oxidized in the atmosphere. You can also.

  In addition, since the conventional drying process is performed in air | atmosphere, depending on temperature conditions, fluorescent substance itself may oxidize and deteriorate. In order to prevent such oxidative degradation, the coating layer can be homogenized and modified by performing heat treatment in a reducing atmosphere such as a nitrogen atmosphere.

  The amount of the compound to be coated is preferably 0.0001 to 20.0 parts by weight with respect to 100 parts by weight of the phosphor. If the amount is less than 0.0001 parts by weight, the effect is small. On the other hand, if the amount is more than 20 parts by weight, the light emission characteristics of the phosphor deteriorate.

Thus, by coating a nitride-based phosphor or an oxynitride-based phosphor with a compound composed of two or more elements, particularly when the phosphor is used as a light-emitting device in combination with an LED, the heat of the phosphor Deterioration due to oxidation caused by water or moisture, or deterioration of a resin or the like due to components contained in the phosphor can be improved, and deterioration of the light emission characteristics can be prevented. By using a composite layer in which two or more kinds of elements are combined in this way, the effect of preventing deterioration over the coating by a single layer can be obtained.
(Nitride-based phosphor manufacturing method)

Next, a composition formula (Sr _a , Ca _1-a ) _x Si _y O _z N _{{(2/3) x + (4/3) y- (2/3) z}} suitable for a nitride-based phosphor: A manufacturing method of x = 2 and y = 5 in Eu will be described. The phosphor preferably contains Mn. Needless to say, the nitride-based phosphor used in the present invention is not limited to this manufacturing method.

  First, raw materials Ca and Sr are pulverized. The raw materials Sr and Ca are preferably used alone, but compounds such as imide compounds and amide compounds can also be used. Sr and Ca obtained by pulverization preferably have an average particle size of about 0.1 μm to 15 μm. The purity of Sr and Ca is preferably 2N.

On the other hand, the raw material Si is pulverized. The raw material Si is preferably used alone. However, nitride compounds, imide compounds, amide compounds and the like can also be used. Furthermore, compounds such as manganese oxide, H ₃ BO ₃ , B ₂ O ₃ , Cu ₂ O, and CuO may be contained. Si is also pulverized in a glove box in an argon atmosphere or a nitrogen atmosphere in the same manner as the raw materials Sr and Ca described above. The average particle size of the Si compound is preferably about 0.1 μm to 15 μm.

  Next, the raw materials Sr and Ca are nitrided in a nitrogen atmosphere. Sr and Ca may be mixed and nitrided, or may be individually nitrided. Thereby, nitrides of Sr and Ca can be obtained. Sr and Ca nitrides preferably have high purity, but commercially available products with lower purity can also be used.

  Further, the raw material Si is nitrided in a nitrogen atmosphere. Si is also nitrided at 800 to 1200 ° C. for about 5 hours in a nitrogen atmosphere. Thereby, silicon nitride is obtained. It is preferable to use high-purity silicon nitride, but commercially available products with lower purity can also be used.

Next, the nitride of Sr, Ca or Sr—Ca is pulverized. Here, the nitride of Sr, Ca, and Sr—Ca is pulverized in a glove box in an argon atmosphere or a nitrogen atmosphere. Similarly, Si nitride is pulverized. Similarly, the Eu compound Eu ₂ O ₃ is ground. The average particle size of the alkaline earth metal nitride, silicon nitride and europium oxide after pulverization is preferably about 0.1 μm to 15 μm. The raw material may contain a small amount of an impurity element that does not impair the characteristics and / or has an effect of improving crystallinity. After the pulverization, Sr, Ca, Sr—Ca nitride, Si nitride, Eu compound Eu ₂ O ₃ and Mn compound are added and mixed.

Finally, a mixture of Sr, Ca, Sr—Ca nitride, Si nitride, and Eu compound Eu ₂ O ₃ is fired in an ammonia atmosphere. By firing, a phosphor represented by Sr—Ca—Si—O—N: Eu to which Mn is added is obtained. At this time, the Mn content is 100 ppm or less.

  However, the composition of the target phosphor can be changed by changing the blending ratio of each raw material. Moreover, although baking can be performed in the range of 1200 to 1700 degreeC, it is set as the baking temperature of 1400 to 1700 degreeC more preferably.

  By forming the phosphor as described above, an aggregated phosphor composition is obtained, and by pulverizing this, a nitride-based phosphor is obtained. It is preferable to classify the phosphor after pulverization or classify it according to the difference in sedimentation characteristics, etc. so that the average particle size is 3 μm or more, and the particle size of 2 μm or less by particle size distribution measurement is 10% or less by volume distribution.

  The nitride phosphors described above are excellent in water resistance, oxidation resistance, and alkali resistance, but are easily baked. Therefore, the nitride phosphor according to the embodiment of the present invention is treated with a compound containing phosphorus.

Next, as an example, a plurality of phosphors coated with a coating layer were manufactured under different conditions, and a test for evaluating the durability and evaluation of fluidity were performed. Further, as a comparative example, a nitride-based phosphor in a state where no coating treatment was performed was similarly prepared, and an endurance test and fluidity evaluation were performed. As durability, the heat resistance test of the content demonstrated below was done. The reduction in luminance in a state where the phosphor was intentionally deteriorated by heating (baking) in air was measured as a relative luminance compared with the luminance before heating, and heat resistance was evaluated. Originally, it is preferable to make a light emitting device (for example, LED) using a semiconductor element for the original evaluation of durability, but it can also be confirmed as a simple evaluation of durability (heat resistance) of the phosphor itself. . The heating condition is 300 ° C. These results are shown in Table 1 and FIG. Table 1 shows the weight parts of each coating layer, the xy on the chromaticity coordinates, the values measured for the relative luminance, and the durability evaluation of each phosphor for the nitride phosphors of the following examples and comparative examples. Therefore, the values obtained by measuring the relative luminance after heating at 300 ° C. in the atmosphere are shown. The measurement of the luminance and chromaticity coordinates xy of the phosphor was performed by exciting at a wavelength of 460 nm. The luminance in the table indicates relative values based on nitride phosphor (Ca, Sr) ₂ Si ₅ N ₈ : Eu in a state where no treatment is performed (Comparative Example 1). As is clear from these results, the phosphor coated with the coating layer is less deteriorated after heating than the phosphor without coating, and the durability is improved without impairing the fluidity. It could be confirmed. Details of each embodiment will be described below.

As Example 1, a (Ca, Sr) ₂ Si ₅ N ₈ phosphor coated with silicon and an aluminum compound was prepared. First, (Ca, Sr) ₂ Si ₅ N ₈ : Eu was synthesized as a nitride-based phosphor by the above method, and then 400 g of deionized water was added to 100 g of the phosphor and stirred. To the dispersion, a potassium silicate solution was added dropwise so that Si was 0.47%, and then an aluminum nitrate solution was added dropwise so that Al was 1.0%. Further, a 2% NH ₃ solution is added dropwise so that the pH is around 6.5 to 6.7. The dispersion after completion of the reaction was filtered and separated and dried. As a result, a (Ca, Sr) ₂ Si ₅ N ₈ phosphor coated with silicon and an aluminum compound was obtained.

  Next, in order to evaluate the durability, the relative luminance in which the decrease in luminance when the phosphor is intentionally deteriorated by heating (baking) in air at 300 ° C. is compared with the luminance before heating. As measured.

  As shown in Table 1, in the case where the film was not treated with the silicon-containing compound, the relative luminance after baking was lowered to 48.7% before baking. On the other hand, the phosphor coated with the silicon and aluminum compounds of Example 1 maintains the relative luminance of 68.0% after baking, and the deterioration due to the thermal oxidation atmosphere (baking) is improved by 20% or more. The effect of preventing the deterioration of the characteristics was confirmed.

As Example 2, a (Ca, Sr) ₂ Si ₅ N ₈ phosphor similarly coated with silicon and a zinc compound was prepared. First, using (Ca, Sr) ₂ Si ₅ N ₈ : Eu, 400 g of deionized water was added to 100 g of the phosphor and stirred. To the dispersion, a potassium silicate solution was added dropwise, and then a zinc sulfate solution was added dropwise so that Zn was 1.0%. Further NH ₃ solution was added dropwise to pH around 7.5-7.7. The dispersion after completion of the reaction was filtered, separated and dried, and a (Ca, Sr) ₂ Si ₅ N ₈ phosphor treated with a silicon compound was obtained.

  When the durability was evaluated by heating in air at 300 ° C., the phosphor coated with the silicon and zinc-containing compound of Example 2 had a relative luminance of 62.7% after baking, and was not treated. It was confirmed that the deterioration due to baking was improved by 10% or more compared with the product.

Similarly, as Example 3, (Ca, Sr) ₂ Si ₅ N ₈ : Eu was used as a nitride-based phosphor, and 400 g of deionized water was added to 100 g of the phosphor and stirred. A potassium silicate solution was added dropwise to the dispersion, and then a magnesium nitrate solution was added dropwise so that Mg was 1.0%. Further, a 2% NaOH solution was added dropwise so that the pH was around 10.5 to 10.7. The dispersion solution after the reaction was filtered, separated and dried, and a (Ca, Sr) ₂ Si ₅ N ₈ phosphor treated with a silicon and magnesium compound was obtained. When the durability was evaluated by heating in air at 300 ° C., the phosphor coated with the silicon and magnesium compounds of Example 3 maintained a relative luminance of 71.7% after baking, and was untreated. It was confirmed that the deterioration due to baking was improved by 20% or more in comparison with.

As Example 4, (Ca, Sr) ₂ Si ₅ N ₈ : Eu was used as a nitride phosphor, and 400 g of deionized water was added to 100 g of the phosphor and stirred. A sodium phosphate solution was added dropwise to the dispersion so that PO ₄ was 1%, and then a magnesium nitrate solution was added dropwise. Further, the pH was adjusted using a 2% KOH solution. Then, the dispersion solution after the reaction was filtered, separated and dried, and a phosphor compound-coated (Ca, Sr) ₂ Si ₅ N ₈ : Eu phosphor was obtained. This phosphor was coated with alumina by the CVD method. Furthermore, when the durability was evaluated by heating in air at 300 ° C., the phosphor coated with the phosphorus-aluminum compound of Example 4 maintained a relative luminance of 92.6% after baking, and was untreated. It was confirmed that the deterioration due to baking was improved by 30% or more compared to the product.

As Example 5, using (Ca, Sr) ₂ Si ₅ N ₈ : Eu as a nitride phosphor, tetraethoxysilane was added so that Si would be 0.93% in a state of being stirred using a mixer, Further, NH3 solution and deionized water were added to perform silica coating treatment. Thereafter, after heat treatment at 200 ° C. or higher, alumina coating treatment was performed by the same CVD method as in Example 4. Furthermore, when the durability was evaluated by heating in the air at 300 ° C., the relative luminance after baking was maintained at 73.7% when the silicon and aluminum compounds of Example 5 were coated, which was improved by nearly 30%. It was confirmed that
(Comparative Example 1)

  On the other hand, as a comparative example, the nitride-based phosphors used in Examples 1 to 4 were each prepared as a comparative example without coating treatment, and heating at 300 ° C. was intentionally deteriorated in an oxidizing atmosphere. As is clear from FIG. 6, the phosphor not subjected to the coating treatment has a remarkable decrease in luminance after the heating test, and the superiority of the coating treatment was confirmed as in the above example.

Next, Table 2 shows the results of evaluating the durability of the phosphors according to Examples 6 and 7. For durability evaluation, heat treatment at 450 ° C. was performed in the same atmosphere as in Examples 1 to 5, and only heat resistance was evaluated. The luminance of the phosphor was measured by exciting with a wavelength of 460 nm. Each luminance in the table is a relative value with reference to Comparative Example 2 in which a nitride phosphor CaAlSiN ₃ : Eu that has not been processed at all is prepared.

In Example 6, CaAlSiN ₃ : Eu was used for the nitride phosphor, and the same treatment as in Example 1 was performed, and coating treatment was performed with silicon and aluminum. Furthermore, when it heated in 450 degreeC air and evaluated durability, when coat | covering with the silicon | silicone of Example 6, and the aluminum compound, it was confirmed that the brightness | luminance is maintained 95.6%.

In Example 7, CaAlSiN ₃ : Eu was used for the nitride phosphor, the same treatment as in Example 5 was performed, and coating was performed with silicon and aluminum. Furthermore, when it heated in 450 degreeC air and evaluated durability, when coat | covered with the silicon | silicone of Example 7, and the aluminum compound, it was confirmed that the brightness | luminance is maintained 93.4%.
(Comparative Example 2)

  On the other hand, as a comparative example, the nitride-based phosphors used in Examples 6 and 7 were prepared without being subjected to coating treatment as comparative examples, and heating at 450 ° C. was intentionally deteriorated in an oxidizing atmosphere. The result is shown in FIG. As is clear from this figure, the phosphor not subjected to the coating treatment had a luminance after heating test lowered to 91.1%, and the superiority of the coating treatment was confirmed as in the above-mentioned example.

  As described above, the surface of the phosphor particles is coated with a compound such as silicon or aluminum by the nitride or oxynitride phosphor of the present invention and the manufacturing method thereof, and durability, particularly deterioration in a thermal oxidation atmosphere. Is improved, and a phosphor having high fluidity is provided. Further, since the phosphor of the present invention is highly stable against heat, it is expected to be a wavelength-converting phosphor for a white light-emitting device having extremely excellent light emission characteristics using a blue light-emitting diode or an ultraviolet light-emitting diode as a light source.

  The light-emitting device, the phosphor for light-emitting element, and the method for producing the same according to the present invention have a light emission characteristic using a fluorescent light-emitting diode, a display, a PDP, a CRT, a FL, a FED, a projection tube, etc. It can be suitably used for an extremely excellent white illumination light source, LED display, backlight light source, traffic light, illumination switch, various sensors, various indicators, and the like.

It is the top view and schematic sectional drawing which show the light-emitting device concerning Embodiment 1 of this invention. It is a schematic cross section which shows the light-emitting device which concerns on Embodiment 2 of this invention. It is a schematic cross section which shows the light-emitting device which concerns on Embodiment 3 of this invention. It is a schematic cross section which shows the light-emitting device which concerns on Embodiment 4 of this invention. It is sectional drawing which shows a mode that the multilayer film was coated on the surface of fluorescent substance. It is a graph which shows a mode that the relative brightness | luminance of the nitride type phosphor which concerns on Examples 1-5 of this invention and the comparative example 1 changes after a heating. It is a graph which shows a mode that the relative brightness | luminance of the nitride-type fluorescent substance which concerns on Example 6, 7 of this invention and the comparative example 2 changes after a heating.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1B, 1C ... Package 2, 2B, 2C ... Semiconductor light emitting element 3, 3B, 3C ... Phosphor layer 4, 4B ... Wire 10 ... Light emitting element; 11 ... Fluorescent member 13 ... Lead frame; 13a ... Mount lead; ... inner lead 14 ... conductive wire; 15 ... mold member 50 ... phosphor; 51 ... first layer; 52 ... second layer

Claims (21)

A light emitting element;
A light-emitting device comprising: a phosphor disposed around the light-emitting element so as to absorb and convert at least part of light emitted from the light-emitting element to a different wavelength;
A light-emitting device, wherein the phosphor is made of a nitride-based fluorescent material or an oxynitride-based fluorescent material containing nitrogen, and the surface of the phosphor has a coating layer containing two or more different compounds. A light emitting element;
A light-emitting device comprising: a phosphor disposed around the light-emitting element so as to absorb and convert at least part of light emitted from the light-emitting element to a different wavelength;
The phosphor is made of a nitride-based fluorescent material or an oxynitride-based fluorescent material containing nitrogen, and at least 40% or more of the surface area of the phosphor is coated with two or more different compounds. Light-emitting device. The light-emitting device according to claim 1,
The light-emitting device, wherein the coating layer has a multilayer structure of two or more layers. The light-emitting device according to any one of claims 1 to 3,
One of the two or more different compounds is a metal oxide, and the other is a compound stable to the metal oxide. The light-emitting device according to any one of claims 1 to 4,
At least one of the two or more different compounds is a metal oxide magnesium oxide, aluminum oxide, boron oxide, yttrium oxide, titanium oxide, silicon oxide, zirconium oxide, zinc oxide, or a combination of two or more of these elements A light emitting device comprising a composite oxide comprising: The light-emitting device according to any one of claims 1 to 4,
At least one of the two or more different compounds is phosphate, calcium phosphate, magnesium phosphate, strontium phosphate, barium phosphate, zinc phosphate, aluminum phosphate, gallium phosphate, indium phosphate, boron phosphate, phosphorus A light-emitting device, which is a composite phosphate composed of bismuth oxide, yttrium phosphate, lanthanum phosphate, cerium phosphate, or a combination of two or more of these elements. The light emitting device according to any one of claims 1 to 6,
A light-emitting device, wherein the phosphor is contained in a translucent resin and disposed around the light-emitting element. The light emitting device according to any one of claims 1 to 7,
The light emitting device, wherein the light emitting element is a light emitting diode. A phosphor for a light emitting element for absorbing at least a part of light emitted from the light emitting element and converting it to a different wavelength,
The phosphor is made of a nitride-based fluorescent material or an oxynitride-based fluorescent material containing nitrogen, and the surface of the phosphor has a coating layer containing two or more different compounds. Phosphor. A phosphor for a light emitting element for absorbing at least a part of light emitted from the light emitting element and converting it to a different wavelength,
The phosphor is made of a nitride-based fluorescent material or an oxynitride-based fluorescent material containing nitrogen, and at least 40% or more of the surface area of the phosphor is coated with two or more different compounds. A phosphor for a light emitting device. The phosphor for a light emitting device according to claim 9,
The phosphor for a light emitting device, wherein the coated compound is present in different and different coating layers. The phosphor for a light emitting device according to any one of claims 9 to 11,
The phosphor is LMN: R, LJMN: R, or LMON: R (L is a group consisting of Be, Mg, Ca, Sr, Ba, Zn). One or more selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf, and J includes B, Al, Ga, In, Sc, 1 or more selected from the group consisting of Y, N is nitrogen, O is oxygen, and R is a rare earth element.) A phosphor for a light emitting device. The phosphor for a light emitting device according to any one of claims 9 to 12,
Said _{phosphor, L x M y N {(} 2/3) x + (4/3) y}: R, L x J w M y N {(2/3) x + w + (4/3) y} , or _{L x M y O z N {} (2/3) x + (4/3) y- (2/3) z}: R (L is Be, Mg, Ca, Sr, Ba, from the group consisting of Zn Contains one or more selected, M contains one or more selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, Hf, J is B, Al, Ga, In, Sc, Y A phosphor for a light-emitting element, comprising at least one selected from the group consisting of: N is nitrogen, O is oxygen, and R is a rare earth element) and has a crystal structure. The phosphor for a light emitting device according to any one of claims 9 to 13,
Said _{phosphor, L x M y N {(} 2/3) x + (4/3) y}: R, L x J w M y N {(2/3) x + w + (4/3) y} , or _{L x M y O z N {} (2/3) x + (4/3) y- (2/3) z}: R (0.5 ≦ x ≦ 3,0.5 ≦ y ≦ 9.0 0.5 ≦ w ≦ 5, 0 ≦ z ≦ 3; L contains one or more selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn, and M is C, Si, Ge, Sn 1 or more selected from the group consisting of Ti, Zr and Hf, J contains one or more selected from the group consisting of B, Al, Ga, In, Sc and Y, N is nitrogen, O Is a oxygen, and R is a rare earth element) and has a crystal structure. The phosphor for a light emitting device according to any one of claims 9 to 14,
Said _{phosphor, L x M y N {(} 2/3) x + (4/3) y}: R, L x J w M y N {(2/3) x + w + (4/3) y} , or _{L x M y O z N {} (2/3) x + (4/3) y- (2/3) z}: R (x = 2,4.5 ≦ y ≦ 6.0,0.01 <Z <1.5, or x = 1, 6.5 ≦ y ≦ 7.5, 0.01 <z <1.5, or x = 1, 1.5 ≦ y ≦ 2.5, 1.5 ≦ z ≦ 2.5; L contains one or more selected from the group consisting of Be, Mg, Ca, Sr, Ba, and Zn, and M consists of C, Si, Ge, Sn, Ti, Zr, and Hf containing one or more members selected from the _{group, L x J w M y N} {(2/3) x + w + (4/3) y}, N is nitrogen, O is oxygen, R is a rare earth element. And a phosphor for a light emitting device, characterized by having a crystal structure. The phosphor for a light emitting device according to any one of claims 9 to 15,
A phosphor for a light-emitting element, wherein the phosphor has a monoclinic or orthorhombic crystal structure. The phosphor for a light emitting device according to any one of claims 9 to 16,
The phosphor for a light emitting device, wherein the phosphor contains a B element. The phosphor for a light emitting device according to any one of claims 9 to 16,
The phosphor for a light emitting element, wherein the phosphor is a phosphor for a light emitting diode. A method for producing a phosphor for a light-emitting element for absorbing at least a part of light emitted from the light-emitting element and converting it to a different wavelength,
On the surface of the phosphor made of nitride-based fluorescent material or oxynitride-based fluorescent material containing nitrogen,
Contacting a coating-containing solution to form a coating layer comprising two or more different compounds;
Heat treating the treated phosphor;
The manufacturing method of the fluorescent substance for light emitting elements characterized by having. A method for producing a phosphor for a light emitting device according to claim 19,
The method for producing a phosphor for a light-emitting element, wherein the heat treatment is performed at 200 ° C. or higher in an atmosphere substantially free of oxygen. A method for producing a phosphor for a light-emitting element according to claim 19 or 20,
The method for producing a phosphor for a light emitting device, wherein the phosphor for a light emitting device is a phosphor for a light emitting diode.

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