JP6524860B2 - Light emitting device - Google Patents

Description

  The present disclosure relates to a light emitting device.

  Various light emitting devices have been developed which emit white light, bulb color and the like by combining a light emitting diode (LED) and a phosphor. As such a light emitting device, a system using a semiconductor light emitting element emitting blue light and a phosphor emitting yellow or the like is well known. Light emitting devices using such semiconductor light emitting elements and phosphors are required to be applied to a wide range of fields such as illuminations such as fluorescent lamps, vehicle illuminations, displays, and backlights for liquid crystals. In particular, in illumination applications, those having high color rendering, which is an index of how the color of an irradiated object is seen, are required together with luminous efficiency. Regarding color rendering, in 1986 the CIE (International Commission on Illumination) published guidelines on color rendering that fluorescent lamps etc should have. According to the guidelines, the preferred average color rendering index (Ra) according to the location to be used is 60 or more and less than 80 for factories that carry out general work, housing, hotels, restaurants, stores, offices, schools, hospitals, precision work In factories that do 80 or more and less than 90, places where clinical examinations are performed, and 90 or more in museums and the like.

In relation to the above, as a red light emitting phosphor, an Mn ⁴⁺ activated fluoride phosphor having a composition such as K ₂ SiF ₆ : Mn having an excitation band in the blue region and a narrow half width of the light emission peak is It is known (for example, refer to patent documents 1). In addition, a white light emitting device including a red phosphor activated with Mn ⁴⁺ and a red phosphor activated with Eu ²⁺ is disclosed (see, for example, Patent Document 2), and is considered to be excellent in luminous efficiency.

Unexamined-Japanese-Patent No. 2010-209311 JP 2012-104814 A

  However, in the white light emitting device described in Japanese Patent Application Laid-Open No. 2012-104814, it has been difficult in some cases to achieve both sufficient color rendering and sufficient luminous flux. An embodiment of the present disclosure is to provide a light emitting device capable of achieving both color rendering and luminous flux at a high level.

The specific means for solving the said subject are as follows.
According to an aspect of the present disclosure, a semiconductor light emitting device having a maximum emission wavelength in a wavelength range of 430 nm to 470 nm, a first phosphor that is a red phosphor having a maximum emission wavelength in a wavelength range of 620 nm to less than 650 nm, and 600 nm or more A second phosphor which is a red phosphor having a maximum emission wavelength in a wavelength range of less than 620 nm, a third phosphor which is a red phosphor having a maximum emission wavelength in a wavelength range of 650 nm or more, and a wavelength of 500 nm to 565 nm A fourth phosphor having a maximum emission wavelength in the range, and the first phosphor has a composition represented by the following formula (I):
A ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
(A is at least one member selected from the group consisting of K ⁺ , Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , and M is a group consisting of a Group 4 element and a Group 14 element At least one element selected, and a represents a number satisfying 0 <a <0.2.

  According to one embodiment of the present disclosure, it is possible to provide a light emitting device capable of achieving both color rendering and luminous flux at a high level.

It is a schematic sectional drawing which shows an example of the light-emitting device which concerns on this embodiment. It is a schematic sectional drawing which shows another example of the light-emitting device which concerns on this embodiment. It is a schematic sectional drawing which shows another example of the light-emitting device which concerns on this embodiment. It is a schematic sectional drawing which shows another example of the light-emitting device which concerns on this embodiment. It is a schematic sectional drawing which shows another example of the light-emitting device which concerns on this embodiment. It is a schematic sectional drawing which shows another example of the light-emitting device which concerns on this embodiment. It is an emission spectrum of the light-emitting device which concerns on the comparative example 1 and 2. FIG. FIG. 6 shows emission spectra of light emitting devices according to Examples 1 to 4 and Comparative Example 1. FIG.

  Hereinafter, embodiments of the present invention will be described in detail. However, the embodiments shown below illustrate the technical concept of the present invention, and the present invention is not limited to the following. The dimensions, materials, shapes, numbers, relative arrangements, etc. of constituent members described in the following embodiments are not intended to limit the scope of the present invention thereto unless specifically described otherwise. , Is just an illustrative example. Note that the size, number, positional relationship, etc. of members shown in each drawing may be exaggerated for the sake of clarity. Further, the relationship between the color name and the chromaticity coordinates, the relationship between the light wavelength range and the color name of the monochromatic light, etc. conform to JIS Z8110. In addition, in the present specification, the term "process" is not limited to an independent process, and can be used as the term if the intended purpose of the process is achieved even if it can not be clearly distinguished from other processes. included. In addition, when there are a plurality of substances corresponding to each component in the composition, the content of each component in the composition means the total amount of the plurality of substances present in the composition unless otherwise specified. .

<Light-emitting device>
The light emitting device of the present embodiment includes: a semiconductor light emitting element having a maximum emission wavelength in a wavelength range of 430 nm to 470 nm; a first phosphor which is a red phosphor having a maximum emission wavelength in a wavelength range of 620 nm to less than 650 nm; A second phosphor which is a red phosphor having a maximum emission wavelength in a wavelength range of 600 nm to less than 620 nm, a third phosphor which is a red phosphor having a maximum emission wavelength in a wavelength range of 650 nm or more, And a fourth phosphor having a maximum light emission wavelength in the wavelength range of (1), wherein the first phosphor is a light emitting device whose composition is represented by the following formula (I).
A ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
In the formula (I), A is at least one member selected from the group consisting of K ⁺ , Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , and M is a Group 4 element and Group 14 At least one element selected from the group consisting of elements, a represents a number satisfying 0 <a <0.2.

The light emitting device has a maximum emission wavelength in the wavelength range of 500 nm to 565 nm and has a maximum emission wavelength in the wavelength range of 620 nm to less than 650 nm in addition to the fourth phosphor emitting green to yellowish green; The first phosphor with a specific chemical composition, the maximum emission wavelength in the wavelength range of 600 nm to less than 620 nm, the second phosphor to be red, and the maximum emission wavelength in the wavelength range of 650 nm or more By including at least three types of red phosphors of the third phosphor that emits red, it is possible to achieve both excellent color rendering properties and excellent luminous flux.
Furthermore, since the first phosphor has less deep red components in a long wave region with low visibility, excellent luminous efficiency can be achieved, and when used for lighting applications, the first phosphor is also excellent in the balance between luminous efficiency and color rendering. In addition to the first phosphor, by including at least two types of red phosphors, which are the second phosphor and the third phosphor, the fluidity of the resin in which the phosphor is dispersed when the light emitting device is manufactured. Can be suppressed, and the light emitting device can be manufactured efficiently.

In the light emitting device of the present embodiment, the average color rendering index Ra is preferably 80 or more, and more preferably 82 or more. The average color rendering index Ra is measured in accordance with JIS Z 8726, the definition of the color rendering evaluation method of a light source.
Further, the color temperature of the light emitting device is not particularly limited, and is appropriately selected according to the purpose and the like. The color temperature of the light emitting device is preferably, for example, 2500 K or more and 3500 K or less. The color temperature of the light emitting device is appropriately selected from, for example, the type and the content of the first phosphor, the second phosphor, the third phosphor and the fourth phosphor (hereinafter collectively referred to simply as "phosphor"). It can be adjusted by doing.

(Semiconductor light emitting device)
The light emitting device includes a semiconductor light emitting element (hereinafter, also simply referred to as “light emitting element”) having a maximum light emission wavelength in a wavelength range of 430 nm to 470 nm. 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 an input, and is resistant to mechanical shock.

  As the semiconductor light emitting element, one emitting light of 430 nm or more and 470 nm or less which is a short wavelength region of visible light, that is, one having an emission peak wavelength (maximum emission wavelength) in a wavelength range of 430 nm or more and 470 nm or less is used. The semiconductor light emitting device preferably has an emission peak wavelength in a wavelength range of 440 nm or more and 460 nm or less. Thereby, the fluorescent substance contained in a light-emitting device can be excited efficiently, and visible light can be used effectively. In addition, by using an excitation light source in the above wavelength range, a light emitting device with high emission intensity can be provided.

As the semiconductor light-emitting device, for example, as a green light emitting element from the blue, that using a nitride semiconductor _{(In X Al Y Ga 1-} X-Y N, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) It can be used.

(First phosphor)
The first phosphor is a red phosphor, has a peak (maximum emission wavelength) of its fluorescence spectrum in a wavelength range of 620 nm or more and less than 650 nm, and has a chemical composition represented by the formula (I).
A ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
A is at least one cation selected from the group consisting of K ⁺ , Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , and M is a group 4 element or group 14 element And at least one element selected from the group consisting of: a represents a number satisfying 0 <a <0.2;

The first phosphor is a red phosphor activated with Mn ⁴⁺ and is capable of absorbing light in the short wavelength region of visible light to emit red light. It is preferable that the excitation light which is the light of the short wavelength region of visible light is mainly the light of a blue region.

  The half width of the emission spectrum of the first phosphor is preferably narrow, and specifically 10 nm or less.

A in the formula (I) is lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), potassium ion (K ⁺ ), rubidium ion (Rb ⁺ ), cesium ion (Cs ⁺ ) and ammonium ion (NH ₄ ⁺ ) And at least one cation selected from the group consisting of Among them, A is preferably at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ and Cs ⁺ and containing at least one of Na ⁺ and K ⁺ . The A ^{is, Li +, Na +, K} +, Rb +, is selected from Cs ⁺ and the group consisting of _NH ^{4 +,} it is also preferably at least one cation containing ^{K +,} mainly ^{K +} It is more preferable that it is a cation such as an alkali metal as a component. Here, “having K ⁺ as the main component” means that the content of K ⁺ in A of the general formula (I) is 80 mol% or more, and is preferably 90 mol% or more, 95 It is more preferable that it is mol% or more.

M in the formula (I) is at least one selected from the group consisting of Group 4 elements and Group 14 elements, and M is titanium (Ti), zirconium (Zr), hafnium from the viewpoint of light emission characteristics. (Hf), silicon (Si), germanium (Ge) and tin (Sn) are preferably at least one selected from the group consisting of silicon (Si) or silicon (Si) and germanium (Ge) It is more preferable to include, and more preferable to be silicon (Si) or silicon (Si) and germanium (Ge).
When M contains silicon (Si) or silicon (Si) and germanium (Ge), part of at least one of Si and Ge contains a group 4 element including Ti, Zr and Hf, and C and Sn It may be substituted by at least one selected from the group consisting of Group 14 elements.
The first phosphor may be used alone or in combination of two or more.

(Second phosphor)
The second phosphor is a red phosphor and has an emission peak wavelength (maximum emission wavelength) of its fluorescence spectrum in a wavelength range of 600 nm or more and less than 620 nm. The second phosphor preferably absorbs light in the short wavelength range of visible light and can emit red light, and the excitation light which is light in the short wavelength range of visible light is mainly light in the blue range Is more preferred. The preferable range of the excitation light in the second phosphor is the same as that of the first phosphor.
The maximum emission wavelength of the second phosphor is preferably 600 nm or more and 610 nm or less from the viewpoint of color rendering and luminous flux.

The second phosphor is preferably an alkaline earth silicon nitride phosphor activated with Eu ²⁺ , and more preferably the chemical composition is represented by the following formula (II).
_{(Ba, Sr, Ca) 2} Si 5 N 8: Eu ··· (II)
The second phosphor may be used alone or in combination of two or more. In addition, about the detail of this fluorescent substance, Unexamined-Japanese-Patent No. 2006-152296 can be referred, for example.

(Third phosphor)
The third phosphor is a red phosphor, and has a light emission peak wavelength (maximum light emission wavelength) of its fluorescence spectrum in a wavelength range of 650 nm or more. The maximum emission wavelength of the third phosphor is preferably 650 nm or more and 670 nm or less from the viewpoint of light emission efficiency. The third phosphor preferably absorbs light in the short wavelength range of visible light and can emit red light, and the excitation light which is light in the short wavelength range of visible light is mainly light in the blue range Is more preferred. The preferred range of excitation light in the third phosphor is the same as in the first phosphor.
The maximum emission wavelength of the third phosphor is also preferably 650 nm or more and 660 nm or less from the viewpoint of color rendering and luminous flux.

The third phosphor is preferably an alkaline earth silicon nitride phosphor activated with Eu ²⁺ , and more preferably the chemical composition is represented by the following formula (III).
CaAlSiN ₃ : Eu (III)
The third phosphor may be used alone or in combination of two or more. For details of this phosphor, for example, International Publication WO2006 / 077740 can be referred to.

The light emitting device includes at least a first phosphor, a second phosphor and a third phosphor as a red phosphor, but may include other red phosphors as needed. Examples of other red phosphors include compounds having a maximum emission wavelength in the wavelength range of 620 nm or more and less than 650 nm, and having a chemical composition other than that of formula (I). Specifically Other red _{phosphor, (Ca, Sr, Ba)} S: can be exemplified Eu or the _{like: Eu, Sr 2 (Si,} Al) 10 (O, N) 14.
When the light emitting device contains other red phosphors, the content thereof is 20% by mass or less in the total mass of the red phosphors, and preferably 10% by mass or less. The lower limit of the content of the other red phosphors is not particularly limited, and is, for example, 0.5% by mass.

The content of the first phosphor, the second phosphor and the third phosphor contained in the light emitting device is not particularly limited. For example, from the viewpoint of color rendering, the content of the first phosphor in the total mass of the red phosphor is preferably 80% by mass to 99% by mass, more preferably 85% by mass to 99% by mass, and 90% by mass. % Or more and 99 mass% or less is more preferable, and 95 mass% or more and 99 mass% or less is more preferable.
The mass ratio of the second phosphor to the third phosphor is preferably 30:70 or more and 70:30 or less from the viewpoint of color rendering and luminous flux.
In particular, when the content of the first phosphor in the total mass of the red phosphor is 90% by mass to 99% by mass, the mass ratio of the second phosphor to the third phosphor is 30:70 to 70. It is preferable that it is: 30 or less.
When the content of the first phosphor in the total mass of the red phosphor is 85% by mass or more and less than 90% by mass, the mass ratio of the second phosphor to the third phosphor is 30: 70 or more and 50 Preferably less than 50.

Although the particle size and particle size distribution of each red phosphor are not particularly limited, it is preferable to show a single peak particle size distribution from the viewpoint of emission intensity, and it is preferable that the particle size distribution of a single peak is narrow in distribution width. preferable.
The particle diameter of the red phosphor is, for example, 1 μm to 100 μm as volume average particle diameter, and preferably 5 μm to 70 μm.

(Fourth phosphor)
The fourth phosphor has a peak of the fluorescence spectrum (maximum emission wavelength) in a wavelength range of 500 nm or more and 565 nm or less. The maximum emission wavelength of the fourth phosphor is preferably 550 nm or more and 560 nm or less from the viewpoint of color rendering and luminous flux. The fourth phosphor absorbs light in the short wavelength region of visible light and can emit yellow to green light. It is preferable that the excitation light which is the light of the short wavelength region of visible light is mainly the light of a blue region.

The fourth phosphor is preferably a composite metal oxide activated with Ce ³⁺ , and its chemical composition is selected from the group consisting of compounds represented by any of the following formulas (IV) to (VI) It is more preferably at least one kind, further preferably at least one kind selected from the group consisting of compounds represented by formula (VI), and the chemical composition is expressed by formula (VIa) It is particularly preferable that it is at least one selected from the group consisting of compounds.
Lu ₃ Al ₅ O ₁₂ : Ce (IV)
Y ₃ (Al, Ga) ₅ O ₁₂ : Ce (V)
(Lu, Y, Gd, Tb) ₃ (Al, Ga) ₅ O ₁₂ : Ce (... (VI)
Y ₃ (Al, Ga) ₅ O ₁₂ : Ce ... (VIa)
The fourth phosphor may be used alone or in combination of two or more.

  The content of the fourth phosphor contained in the light emitting device is not particularly limited, and may be appropriately selected so that various characteristics such as the color temperature of the light emitting device have desired values.

The particle size and particle size distribution of the fourth phosphor are not particularly limited, but it is preferable to exhibit a single peak particle size distribution from the viewpoint of emission intensity.
The particle diameter of the fourth phosphor is, for example, 1 μm or more and 100 μm or less as a volume average particle diameter, and preferably 5 μm or more and 70 μm or less.

  The phosphor contained in the light emitting device may be contained, for example, in a fluorescent material that covers the semiconductor light emitting element. The fluorescent material can include a phosphor and a resin. The content of the phosphor in the fluorescent material is not particularly limited, and can be appropriately selected according to the various characteristics of the light emitting device. The total content of the phosphor can be, for example, 50 parts by mass or more and 170 parts by mass or less with respect to 100 parts by mass of the resin contained in the fluorescent material.

The light emitting device may include a filler in the fluorescent material. Examples of the filler include silica, titania, zirconia and the like. The fillers may be used alone or in combination of two or more.
When the light emitting device contains a filler in the fluorescent material, the total content of the filler can be, for example, 0.5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the resin contained in the fluorescent material.

  The type of the light emitting device is not particularly limited, and can be appropriately selected from commonly used types. As a type of light emitting device, a pin penetration type, a surface mounting type, etc. can be mentioned. In general, the through-pin type refers to one in which a light emitting device is fixed by penetrating a lead (pin) of the light emitting device in a through hole provided in a mounting substrate. The surface mount type refers to one that fixes the leads of the light emitting device on the surface of the mounting substrate.

Hereinafter, an example of a light emitting device according to the present embodiment will be described based on the drawings. FIG. 1 is a schematic cross-sectional view showing an example of a light emitting device according to the present embodiment. This light emitting device is an example of a surface mounted light emitting device.
The light emitting device 100 emits the light emitting element 10 and the light emitting element 10 of a gallium nitride based compound semiconductor that emits light on the short wavelength side (for example, 380 nm or more and 485 nm or less) of visible light and has an emission peak wavelength of 430 nm or more and 470 nm or less And a formed body 40. In the molded body 40, the first lead 20 and the second lead 30, and a thermoplastic resin or a thermosetting resin are integrally molded. The molded body 40 forms a recess having a bottom surface and a side surface, and the light emitting element 10 is mounted on the bottom surface of the recess. The light emitting element 10 has a pair of positive and negative electrodes, and the pair of positive and negative electrodes is electrically connected to the first lead 20 and the second lead 30 through the wire 60. The light emitting element 10 is covered by a fluorescent member 50. The fluorescent member 50 preferably contains a thermosetting resin such as an epoxy resin, a silicone resin, an epoxy-modified silicone resin, or a modified silicone resin. The fluorescent member 50 contains the fluorescent substance 70 which wavelength-converts the light from the light emitting element 10, and each fluorescent substance 70 is a 1st fluorescent substance, a 2nd fluorescent substance, a 3rd fluorescent substance, or a 4th fluorescent substance, The phosphor of the above is contained at a predetermined content ratio. In the light emitting device 100, mixed light of the light from the light emitting element 10 and the light from the phosphor 70 excited by the light from the light emitting element 10 is extracted from the light emitting surface of the fluorescent member 50. The light emitting surface of the fluorescent member 50 is located on the side opposite to the side on which the first lead 20 and the second lead 30 are disposed.

  The fluorescent member 50 is formed by being filled with a translucent resin or glass so as to cover the light emitting element 10 placed in the recess of the light emitting device 100. In consideration of the ease of manufacture, the material of the fluorescent member is preferably a translucent resin. As the light transmitting resin, it is preferable to use a silicone resin composition in consideration of light resistance, but an insulating resin composition such as an epoxy resin composition or an acrylic resin composition can also be used. The fluorescent member 50 contains the fluorescent substance 70 including the first fluorescent substance, the second fluorescent substance, the third fluorescent substance, and the fourth fluorescent substance, but other materials can be added as appropriate. . For example, by including a light diffusion material, directivity of the light-emitting element can be relaxed and a viewing angle (half angle) can be increased.

  The fluorescent member 50 functions not only as a wavelength conversion member including the fluorescent body 70 but also as a member for protecting the light emitting element 10 and the fluorescent body 70 from the external environment. In FIG. 1, the phosphors 70 are dispersed at a substantially uniform rate throughout the fluorescent member 50. Thereby, it is possible to obtain light in which color unevenness is further suppressed. Further, the influence of heat from the light emitting element 10 on the phosphor 70 can be mitigated. The phosphors 70 may be unevenly distributed in the fluorescent member 50. When the fluorescent substance 70 is localized, the fluorescent substance 70 may be disposed close to the light emitting element 10. Thereby, a light emitting device which is more excellent in light emission efficiency can be configured. Further, in consideration of the influence of heat on the phosphor 70, the light emitting element 10 and the phosphor 70 can be arranged in the fluorescent member 50 with a space.

  In FIG. 1, the first fluorescent substance, the second fluorescent substance, the third fluorescent substance and the fourth fluorescent substance contained in the fluorescent substance 70 are illustrated in a mixed state, but as shown in FIG. You may arrange the body. FIG. 2 is a schematic cross-sectional view showing another example of the light emitting device according to the present embodiment. The fluorescent member 50 shown in FIG. 2 includes, in order from the side closer to the light emitting element 10, a portion where the fourth phosphor 74 is contained, and a portion where the third phosphor 73 and the second phosphor 72 are mixed and contained, And a portion where the first phosphor 71 is included. By arranging the first fluorescent substance 71 away from the light emitting element 10, the influence of the heat from the light emitting element 10 of the first fluorescent substance 71 can be mitigated, and deterioration of the first fluorescent substance 71 due to heat is effective. Can be suppressed. In FIG. 2, the second phosphor 72 and the third phosphor 73 are mixed and arranged, but the second phosphor 72 and the third phosphor 73 are separated and arranged so as to be included in separate portions. It may be In that case, for example, the second phosphor 72 may be disposed on the third phosphor 73.

  FIG. 3 is a schematic cross-sectional view showing another example of the light emitting device according to the present embodiment. The fluorescent member 50 shown in FIG. 3 includes, in order from the side closer to the light emitting element 10, a portion where the third phosphor 73 and the second phosphor 72 are mixed and contained, and a portion where the fourth phosphor 74 is contained, And a portion where the first phosphor 71 is included. By arranging the first fluorescent substance 71 away from the light emitting element 10, the influence of the heat from the light emitting element 10 of the first fluorescent substance 71 can be mitigated, and deterioration of the first fluorescent substance 71 due to heat is effective. Can be suppressed. In FIG. 3, the second phosphor 72 and the third phosphor 73 are mixed and arranged, but the second phosphor 72 and the third phosphor 73 are separated and arranged so as to be included in separate portions. It may be In that case, for example, the second phosphor 72 may be disposed on the third phosphor 73.

  FIG. 4 is a schematic cross-sectional view showing another example of the light emitting device according to the present embodiment. The fluorescent member 50 shown in FIG. 4 includes, in order from the side closer to the light emitting element 10, a portion including the third fluorescent body 73, a portion including the second fluorescent body 72, and a portion including the first fluorescent body 71. And a site where the fourth phosphor 74 is included. The fourth phosphor 74 is disposed on the red phosphor including the first phosphor 71, the second phosphor 72, and the third phosphor 73, so that the light emitted from the fourth phosphor 74 is a red phosphor. Can be suppressed, and the light emission of the fourth phosphor 74 can be more efficiently taken out of the light emitting device. Although the second fluorescent substance 72 is disposed on the third fluorescent substance 73 in FIG. 4, the third fluorescent substance 73 may be disposed on the second fluorescent substance 72. The third phosphor 73 may be mixed and disposed.

  FIG. 5 is a schematic cross-sectional view showing another example of the light emitting device according to the present embodiment. The fluorescent member 50 shown in FIG. 5 includes, in order from the side closer to the light emitting element 10, a portion where the first phosphor 71 is contained, a portion where the third phosphor 73 and the second phosphor 72 are mixed and contained, and And a site where the four phosphors 74 are included. Since the first phosphor 71 is disposed apart from the outermost surface of the light emitting device 100, the influence of moisture that can penetrate from the outermost surface to the first phosphor 71 can be suppressed, and light emission with higher durability is achieved. The device can be configured. Further, in FIG. 5, by arranging the fourth fluorescent substance 74 on the red fluorescent substance, it is possible to suppress that the light emitted from the fourth fluorescent substance 74 excites the red fluorescent substance, and the light emission of the fourth fluorescent substance 74 It can be more efficiently taken out of the light emitting device. In FIG. 5, the second phosphor 72 and the third phosphor 73 are mixed and arranged, but the second phosphor 72 and the third phosphor 73 are separated and arranged so as to be included in separate portions. It may be In that case, for example, the second phosphor 72 may be disposed on the third phosphor 73.

  FIG. 6 is a schematic cross-sectional view showing another example of the light emitting device according to the present embodiment. The fluorescent member 50 shown in FIG. 6 includes, in order from the side closer to the light emitting element 10, a portion including the fourth phosphor 74, a portion including the first phosphor 71, the third phosphor 73 and the second fluorescence. Body 72 is mixed and contained. The first fluorescent substance 71 is disposed with the site where the third fluorescent substance 73 and the second fluorescent substance 72 are mixed and contained between the first fluorescent substance 71 and the outermost surface of the light emitting device 100. Thus, the influence of moisture that may intrude from the outermost surface of the light emitting diode can be suppressed, and a light emitting device with higher durability can be configured. In FIG. 6, the second fluorescent substance 72 and the third fluorescent substance 73 are mixed and arranged, but the second fluorescent substance 72 and the third fluorescent substance 73 are separated and arranged so as to be included in separate portions. It may be In that case, for example, the second phosphor 72 may be disposed on the third phosphor 73.

  Hereinafter, the present embodiment will be specifically described by way of examples, but the present embodiment is not limited to these examples.

The following materials were used in the following examples and comparative examples.
Semiconductor light emitting element: LED chip having a maximum emission wavelength of 455 nm First phosphor: K ₂ [Si _0.97 Mn ⁴⁺ _0.03 F ₆ ] (hereinafter also referred to as “KSF”), maximum emission wavelength of 630 nm Red phosphor.
Second phosphor: Ba _1.33 Sr _0.63 Si ₅ N ₈ : Eu _0.44 (hereinafter, also referred to as “BSESN”), a red phosphor having a maximum emission wavelength of 607 nm.
Third phosphor: Ca _0.993 AlSiN ₃ : Eu _0.007 (hereinafter, also referred to as “CASN”), a red phosphor having a maximum emission wavelength of 650 nm.
Fourth phosphor: Y ₃ (Al, Ga) ₅ O ₁₂ : Ce (hereinafter, also referred to as “YAG”), a yellow phosphor having a maximum emission wavelength of 556 nm.

(Production of light emitting device)
A red phosphor and a yellow phosphor are mixed and dispersed in a silicone resin (Shin-Etsu Chemical Co., Ltd.) so that the composition of the red phosphor is as shown in Table 1 and the color temperature is 3450 K. A resin composition was obtained. Next, the phosphor-containing resin composition was injected onto the LED package (maximum emission wavelength 455 nm) and filled, and the resin composition was cured by heating at 150 ° C. for 4 hours to produce a light emitting device.
In the table, “KSF content (%) in red phosphor” and “BSESN: CASN” are based on mass.

(Emission spectrum)
The emission spectrum of the obtained light emitting device was measured. The emission spectrum obtained is shown in FIG. 7 and FIG.
FIG. 7 is an emission spectrum of the light emitting device according to Comparative Examples 1 and 2. FIG. 8 is an emission spectrum of the light emitting device according to Examples 1 to 4 and Comparative Example 1. Both FIG. 7 and FIG. 8 show relative light emission intensities standardized with the light emission intensity at the maximum light emission wavelength of KSF which is the maximum of the light emission intensity among the light emission spectra of the light emitting devices in each comparative example and example.

(Color rendering)
About the obtained light-emitting device, the average color rendering index Ra was calculated according to the method of evaluating color rendering of a light source according to JIS Z 8726.

(Relative luminous flux)
The luminous flux of the obtained light emitting device was measured using an integrating sphere, and the relative luminous flux was calculated with the luminous flux in Comparative Example 1 as 100%.

The relative amount of KSF can be reduced by combining at least one of the second phosphor (BSESN) and the third phosphor (CASN) in addition to the first phosphor (KSF) as a red phosphor. Thereby, the fluidity of the resin containing the phosphor is improved, and the light emitting device can be manufactured with good workability.
Further, it is understood that color rendering property and relative luminous flux can be compatible by combining the second phosphor (BSESN) and the third phosphor (CASN) in addition to the first phosphor (KSF) as a red phosphor.
On the other hand, when only the second phosphor (BSESN) is combined with the first phosphor (KSF) as a red phosphor, the relative luminous flux is increased but the color rendering property is lowered. In addition, when only the third phosphor (CASN) is combined with the first phosphor (KSF) as a red phosphor, although sufficient color rendering can be obtained, a sufficient relative luminous flux can not be obtained.

  The light emitting device of the present invention is suitable as a light source for illumination, and can be applied to a luminaire.

  10: light emitting element, 50: fluorescent member, 70: phosphor, 100: light emitting device

Claims (11)

A semiconductor light emitting device having a maximum emission wavelength in a wavelength range of 430 nm to 470 nm;
A first phosphor which is a red phosphor having a maximum emission wavelength in a wavelength range of 620 nm or more and less than 650 nm;
A second phosphor which is a red phosphor having a maximum emission wavelength in a wavelength range of 600 nm or more and less than 620 nm;
A third phosphor which is a red phosphor having a maximum emission wavelength in a wavelength range of 650 nm or more;
And a fourth phosphor having a maximum emission wavelength in a wavelength range of 500 nm to 565 nm,
The composition of the first phosphor is represented by the following formula (I)
A ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
(A is at least one member selected from the group consisting of K ⁺ , Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , and M is a group consisting of a Group 4 element and a Group 14 element at least one element selected, a is represented by.) indicating a number satisfying 0 <a <0.2,
The composition of the second phosphor is
_{(Ba, Sr, Ca) 2} Si 5 N 8: Eu
Represented by
The composition of the third phosphor is
CaAlSiN ₃ : Eu
Represented by
The content ratio of the first phosphor in the total mass of the red phosphor is 80% by mass or more and less than 99% by mass, and the mass ratio of the second phosphor to the third phosphor is 30:70 or more and 70:30 or less And a light emitting device whose color temperature is 2500 K or more and 3500 K or less . The fourth phosphor has a composition of Lu ₃ Al ₅ O ₁₂ : Ce,
Y ₃ (Al, Ga) ₅ O ₁₂ : Ce and (Lu, Y, Gd, Tb) ₃ (Al, Ga) ₅ O ₁₂ : Ce
The light-emitting device according to claim 1, wherein the light-emitting device is at least one selected from the group consisting of compounds represented by any one of the above. The content of the first phosphor in the total mass of the red phosphor is 90% by mass to 99% by mass,
The mass ratio of the second phosphor to the third phosphor is 30:70 or more and 70:30 or less,
A light emitting device according to claim 1 or 2 . The content of the first phosphor in the total mass of the red phosphor is 85% by mass or more and less than 90% by mass,
The light emitting device according to any one of claims 1 to 3 , wherein a mass ratio of the second phosphor to the third phosphor is 30:70 or more and less than 50:50. The first phosphor, the second phosphor, the third phosphor, and the fourth phosphor cover the semiconductor light emitting element and are contained in a fluorescent member containing a resin, and the total content of the phosphor is 100% resin. It is 50 mass parts or more and 170 mass parts or less with respect to part, The light-emitting device of any one of Claim 1 to 4 . The first fluorescent material, the second fluorescent material, the third fluorescent material and the fourth fluorescent material are included in the fluorescent member covering the semiconductor light emitting device, and the fluorescent members are arranged in order from the one closer to the semiconductor light emitting device The method according to any one of claims 1 to 5, comprising a portion in which the fluorescent substance is contained, a portion in which the third fluorescent substance and the second fluorescent substance are mixed and contained, and a portion in which the first fluorescent substance is contained. The light emitting device according to claim 1. The first fluorescent material, the second fluorescent material, the third fluorescent material and the fourth fluorescent material are included in the fluorescent member covering the semiconductor light emitting device, and the fluorescent members are arranged in order from the one closer to the semiconductor light emitting device The method according to any one of claims 1 to 5, comprising a portion in which the phosphor and the second phosphor are mixed and contained, a portion in which the fourth phosphor is contained, and a portion in which the first phosphor is contained. The light emitting device according to claim 1. The first fluorescent material, the second fluorescent material, the third fluorescent material and the fourth fluorescent material are included in the fluorescent member covering the semiconductor light emitting device, and the fluorescent members are arranged in order from the one closer to the semiconductor light emitting device The method according to any one of claims 1 to 5, comprising a portion in which the fluorescent substance is contained, a portion in which the third fluorescent substance and the second fluorescent substance are mixed and contained, and a portion in which the first fluorescent substance is contained. The light emitting device according to claim 1. The first fluorescent material, the second fluorescent material, the third fluorescent material and the fourth fluorescent material are included in the fluorescent member covering the semiconductor light emitting device, and the fluorescent members are arranged in order from the one closer to the semiconductor light emitting device The method according to any one of claims 1 to 5, comprising a portion in which the fluorescent substance is contained, a portion in which the second fluorescent substance is contained, a portion in which the first fluorescent substance is contained, and a portion in which the fourth fluorescent substance is contained. The light emitting device according to item 1. The first fluorescent material, the second fluorescent material, the third fluorescent material and the fourth fluorescent material are included in the fluorescent member covering the semiconductor light emitting device, and the fluorescent members are arranged in order from the one closer to the semiconductor light emitting device The method according to any one of claims 1 to 5, comprising a portion in which the fluorescent substance is contained, a portion in which the third fluorescent substance and the second fluorescent substance are mixed and contained, and a portion in which the fourth fluorescent substance is contained. The light emitting device according to claim 1. The first fluorescent material, the second fluorescent material, the third fluorescent material and the fourth fluorescent material are included in the fluorescent member covering the semiconductor light emitting device, and the fluorescent members are arranged in order from the one closer to the semiconductor light emitting device The method according to any one of claims 1 to 5, comprising a portion in which the fluorescent substance is contained, a portion in which the first fluorescent substance is contained, and a portion in which the third fluorescent substance and the second fluorescent substance are mixed and contained. The light emitting device according to claim 1.