JP2013185045A - Fluorescent substance and light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent substance which is efficiently excited with an excitation light of wide wavelength range and emits green fluorescent light, the emitted light having a small variation in emission intensity with the change in wavelength of excited light, and further can be easily manufactured.SOLUTION: A fluorescent substance is represented by following formula (1): A(M-Eu)LSiO(wherein A is at least one element selected from Li, Na, K and Rb; M is at least one element selected from Ca, Sr and Ba; L is at least one element selected from Ga, Al, Sc, Y, La, Gd and Lu; and a is a number satisfying 0.001≤a≤0.3).

Description

  The present invention relates to a phosphor and a light-emitting device including the phosphor.

  In recent years, with the improvement of the light emission efficiency of light emitting diodes (LEDs), light emitting devices using LEDs are becoming popular and expanding. In particular, a light-emitting device including an LED and a phosphor that converts the wavelength of light emitted from the LED can be highly efficient, small, thin, and power-saving, and can be arbitrarily selected depending on the application such as white color or light bulb color. Features such as the ability to emit light in color. For this reason, this type of light-emitting device can be used for indoor and outdoor lighting fixtures, liquid crystal displays, backlight light sources for mobile phones and personal digital assistants, display devices used for indoor and outdoor advertisements, in-vehicle light sources, and the like. Expected and being developed.

  Various configurations have been proposed as a configuration of a light emitting device that emits white light. Among them, a light emitting device (for example, see Patent Document 1) including a blue LED and a yellow phosphor is most popular. In this light emitting device, it is utilized that blue and yellow are in a complementary color relationship, and a part of blue light emitted from the blue LED is converted into yellow light by a yellow phosphor, so that the light emitting device emits blue light. Pseudo white light including yellow light is emitted.

  However, although the luminous efficiency of such a light emitting device that emits pseudo white light is high, the pseudo white light contains little or no green light and red light, and thus has a problem of low color rendering. .

  As a light emitting device that emits white light, a light emitting device that includes a blue LED, a green phosphor, and a red phosphor (see, for example, Patent Document 2), and a light emitting device that includes a near ultraviolet LED, a blue phosphor, a green phosphor, and a red phosphor. An apparatus (see, for example, Patent Document 3) has also been proposed. These light emitting devices emit white light that is relatively close to natural light including blue light, green light, and red light.

  In Patent Document 2, as a green phosphor, it absorbs blue light emission, can emit a light emission spectrum having a peak at 530 to 570 nm, and extending to at least 700 nm, has a garnet structure and contains cerium. A photoluminescent phosphor is disclosed.

Patent Document 3 discloses a phosphor having a general formula Eu _s (Si, Al) _6-s (O, N) ₈ and having a beta sialon crystal structure as a green phosphor. In this general formula, s is a number from 0.011 to 0.019.

Japanese Patent No. 3700502 Japanese Patent No. 4148245 Japanese Patent No. 4104013

However, in the green phosphor disclosed in Patent Document 2, since the ion serving as the emission center is Ce ³⁺ , the wavelength range of the excitation light is 440 to 400 nm in order to stabilize the emission intensity of the green phosphor. It will be limited to the range of 460 nm. For this reason, this green phosphor is effective only when used with a blue LED. For example, when used with a near-ultraviolet LED, there is a problem that the emission intensity of the green phosphor does not increase sufficiently. Furthermore, even when this green phosphor is used with a blue LED, the emission wavelength of the blue LED varies depending on the production lot of the blue LED, or the emission wavelength fluctuates due to the temperature rise of the blue LED. There is also a problem that the emission intensity of the green phosphor easily fluctuates greatly. For this reason, the luminous flux and chromaticity of white light emitted from the light emitting device are likely to fluctuate.

  The green phosphor disclosed in Patent Document 3 is manufactured through a process in which the raw material is baked at a high temperature of 1820 ° C. to 2200 ° C. in a nitrogen atmosphere. For this reason, there is a problem in that a manufacturing facility for high-temperature heating is required and the manufacturing process becomes very complicated, resulting in an increase in manufacturing cost.

  The present invention has been made in view of the above-mentioned reasons, and the object of the present invention is to be excited efficiently by excitation light in a wide wavelength region to emit green fluorescence, and the change in emission intensity with respect to wavelength variation of excitation light. An object of the present invention is to provide a phosphor that is small and can be easily manufactured, and a light-emitting device including the phosphor.

  The phosphor according to the present invention is represented by the following composition formula (1).

A (M _1-a Eu _a ) LSi ₃ O ₉ (1)
(A is one or more elements selected from Li, Na, K and Rb. M is one or more elements selected from Ca, Sr and Ba. L is Ga, Al, Sc, Y, La, Gd. And one or more elements selected from Lu. A is a number satisfying 0.001 ≦ a ≦ 0.3.)
It is preferable that L in the composition formula (1) includes Sc.

  It is also preferable that M in the composition formula (1) includes at least one of Ba and Sr.

  It is also preferable that A in the composition formula (1) includes Rb.

  It is also preferable that the phosphor according to the present invention is represented by the following composition formula (2).

Rb (Ba _1-a Eu _a ) ScSi ₃ O ₉ (2)
It is also preferable that A in the composition formula (1) contains K.

  The light emitting device according to the present invention includes a light emitting element and a wavelength conversion member that emits light by absorbing light emitted from the light emitting element, and the wavelength conversion member includes the phosphor.

  The main emission peak of light emitted from the light emitting element is preferably in the range of 350 nm to 470 nm.

  The phosphor according to the present invention is efficiently excited by excitation light in a wide wavelength region to emit green fluorescence, and the change in emission intensity with respect to the wavelength variation of the excitation light is small, and can be easily manufactured.

  The light emitting device according to the present invention exhibits high luminous efficiency and wavelength conversion efficiency by including the phosphor.

It is a partially broken disassembled perspective view which shows the light-emitting device in one Embodiment of this invention. It is sectional drawing of the said light-emitting device. For particles of the phosphor according to Examples 1 to 4, the diffraction intensity curve obtained by powder X-ray diffraction measurement, as well as RbBaScSi ₃ O _9, which is a graph showing the diffraction intensity curve obtained by simulation. It is a graph which shows the emission spectrum and excitation spectrum of the fluorescent substance which concerns on Examples 1-4. For particles of the phosphor according to Examples 6 and 8, the diffraction intensity curve obtained by powder X-ray diffraction measurement, as well as RbBaScSi ₃ O _9, which is a graph showing the diffraction intensity curve obtained by simulation. It is a graph which shows the emission spectrum and excitation spectrum of the fluorescent substance which concerns on Example 2, 5-8. For particles of the phosphor according to Examples 9 and 10, the diffraction intensity curve obtained by powder X-ray diffraction measurement, as well as RbBaScSi ₃ O _9, which is a graph showing the diffraction intensity curve obtained by simulation. For particles of the phosphor according to Example 11 to 13, the diffraction intensity curve obtained by powder X-ray diffraction measurement, as well as RbBaScSi ₃ O _9, which is a graph showing the diffraction intensity curve obtained by simulation. It is a graph which shows the emission spectrum and excitation spectrum of the fluorescent substance concerning Example 2, 9 and 10. It is a graph which shows the light emission spectrum and excitation spectrum of the fluorescent substance which concerns on Example 2, 11 thru | or 13. For particles of the phosphor according to Example 14, the diffraction intensity curve obtained by powder X-ray diffraction measurement, as well as RbBaScSi ₃ O _9, which is a graph showing the diffraction intensity curve obtained by simulation. It is a graph which shows the emission spectrum and excitation spectrum of the fluorescent substance concerning Example 2 and 14. For particles of the phosphor according to Example 15, the diffraction intensity curve obtained by powder X-ray diffraction measurement, as well as RbBaScSi ₃ O _9, which is a graph showing the diffraction intensity curve obtained by simulation. It is a graph which shows the light emission spectrum and excitation spectrum of the fluorescent substance concerning Example 2 and 15. For particles of the phosphor according to Example 16, the diffraction intensity curve obtained by powder X-ray diffraction measurement, as well as RbBaScSi ₃ O _9, which is a graph showing the diffraction intensity curve obtained by simulation. It is a graph which shows the emission spectrum and excitation spectrum of the fluorescent substance which concerns on Example 2 and 16. For particles of the phosphor according to Example 17, the diffraction intensity curve obtained by powder X-ray diffraction measurement, as well as RbBaScSi ₃ O _9, which is a graph showing the diffraction intensity curve obtained by simulation. It is a graph which shows the emission spectrum and excitation spectrum of the fluorescent substance concerning Example 2 and 17.

[Phosphor]
The phosphor according to the present embodiment is represented by the following composition formula (1).

A (M _1-a Eu _a ) LSi ₃ O ₉ (1)
(A is one or more elements selected from Li, Na, K and Rb. M is one or more elements selected from Ca, Sr and Ba. L is Ga, Al, Sc, Y, La, Gd. And one or more elements selected from Lu. A is a number satisfying 0.001 ≦ a ≦ 0.3.)
This phosphor is a silicate-based phosphor activated with divalent europium ions. In the phosphor crystal having such a composition, the ion serving as the emission center is the divalent europium ion Eu ²⁺ . This Eu ²⁺ is dissolved in the crystal by substituting this Eu in part of the site occupied by the divalent ions of the metal element M in the crystal. By having such a structure, the phosphor is efficiently excited by absorbing excitation light in a wide wavelength range shorter than the green range, and efficiently emits green fluorescence.

  In the composition formula (1), as described above, A is one or more alkali metal elements selected from Li, Na, K, and Rb. A may be composed of only one element of Li, Na, K and Rb, or may be composed of two or more elements. When A consists of two or more elements, the ratio of each of the two or more elements in A may be an appropriate ratio.

  In particular, it is preferable that A in the composition formula (1) includes at least one of Rb and K. In particular, it is preferable that A consists of only Rb, or A consists of only K, or A consists of only Rb and K. In this case, the luminous efficiency of the phosphor is particularly high.

  In the composition formula (1), as described above, M is one or more elements selected from Ca, Sr, and Ba. M may be composed of only one element of Ca, Sr and Ba, or may be composed of two or more elements. When M is composed of two or more elements, the ratio of each of the two or more elements in M may be an appropriate ratio. In the crystal, the metal element M becomes a divalent ion as described above.

  In particular, it is preferable that M in the composition formula (1) includes at least one of Ba and Sr. In particular, it is preferable that M consists only of Ba, or that M consists only of Sr, or that M consists only of Ba and Sr. In this case, the luminous efficiency of the phosphor is particularly high.

  The combination of A and M in the composition formula (1) is appropriately selected. As a preferable combination of A and M, when A includes Rb and M includes one or both of Ba and Sr, A includes K and M includes one or both of Ba and Sr. In the case where A is contained, for example, A contains Li and M contains Ca.

  In the composition formula (1), a is a number indicating the molar ratio of Eu to the metal element M, and is a number satisfying 0.001 ≦ a ≦ 0.3 as described above. When the value of a is 0.001 or more, the concentration of divalent europium ions in the crystal becomes sufficiently high. Further, when the value of a is 0.3 or less, concentration quenching is suppressed, and thereby the emission intensity of the phosphor is sufficiently increased. In order to further reduce concentration quenching, the value of a is particularly preferably 0.2 or less. That is, when a is a number satisfying 0.001 ≦ a ≦ 0.2, the emission intensity of the phosphor is particularly high. Furthermore, it is preferable that a is a number satisfying 0.05 ≦ a ≦ 0.15.

  In the composition formula (1), as described above, L is one or more elements selected from Ga, Al, Sc, Y, La, Gd, and Lu. L may be composed of only one element of Ga, Al, Sc, Y, La, Gd, and Lu, or may be composed of two or more elements. When L consists of two or more elements, the ratio of each of the two or more elements in L may be an appropriate ratio. In the crystal, the metal element L becomes a trivalent ion.

  In the composition formula (1), L preferably contains Sc. In this case, the luminous efficiency of the phosphor is particularly high. In particular, it is preferable that Sc is contained in L in a range of 70 mol% to 100 mol%.

  A preferable aspect in the present embodiment will be further described.

  In the first embodiment, the phosphor is represented by the following composition formula (2).

Rb (Ba _1-a Eu _a ) ScSi ₃ O ₉ (2)
In the composition formula (2), a is a number satisfying 0.001 ≦ a ≦ 0.3 as described above. This a preferably satisfies 0.001 ≦ a ≦ 0.2, and more preferably satisfies 0.05 ≦ a ≦ 0.15.

  In the second embodiment, the phosphor is represented by the following composition formula (3).

Rb ((Ba _1-b Sr _b ) _1-a Eu _a ) ScSi ₃ O ₉ (3)
In the composition formula (3), a is a number satisfying 0.001 ≦ a ≦ 0.3 as described above. This a preferably satisfies 0.001 ≦ a ≦ 0.2, and more preferably satisfies 0.05 ≦ a ≦ 0.15. In the composition formula (3), b is a number satisfying 0 <b ≦ 1. In particular, b is preferably a number satisfying 0.5 ≦ b ≦ 0.85.

  An example of a method for manufacturing a phosphor will be described. First, a mixture is prepared by blending multiple types of raw materials. The blending ratio of the raw materials is adjusted so that the metal element in the mixture matches the composition represented by the composition formula (1).

Examples of the raw material include a single metal constituting the phosphor and a compound such as an oxide or a salt of the metal constituting the phosphor. More specifically, the Li ₂ CO ₃ as an example of a material containing Li, is Na ₂ CO ₃ as an example of a raw material containing Na, is K ₂ CO ₃ as an example of a raw material containing K, of raw material containing Rb example Rb ₂ CO ₃ as an example of a raw material containing Ca, CaCO ₃ as an example of a raw material containing SrCO ₃ as an example of a raw material containing Sr, BaCO ₃ as an example of a raw material containing Ba, and Eu ₂ O as an example of a raw material containing Eu ₃ is an example of a raw material containing Ga, Ga ₂ O ₃ is an example of a raw material containing Al, Al ₂ O ₃ is an example of a raw material containing Sc, Sc ₂ O ₃ is an example of a raw material containing Sc, and an example of a raw material containing Y Y ₂ O ₃ is an example of a raw material containing La, La ₂ O ₃ is an example of a raw material containing Gd, Gd ₂ O ₃ is an example of a raw material containing Lu, Lu ₂ O ₃ is an example of a raw material containing Si, An example is SiO ₂ .

  Next, a container made of a material such as alumina or quartz is prepared, and the mixture is placed in the container. Subsequently, the mixture in the container is fired at a temperature of 1000 to 1300 ° C. in a non-oxidizing gas atmosphere. The non-oxidizing gas atmosphere is preferably a weak reducing gas atmosphere such as a hydrogen / nitrogen mixed gas atmosphere. Thus, before a mixture is baked, a mixture may be pre-baked in air | atmosphere previously, and the crystallinity of fluorescent substance becomes especially high in this case. When the mixture is temporarily fired, the firing temperature at the time of temporary firing is preferably equal to or lower than the firing temperature at the time of main firing (when firing in the non-oxidizing gas atmosphere following the temporary firing).

  Thus, the phosphor according to the present embodiment can be manufactured through a process in which the raw material is baked at a relatively low temperature of 1000 to 1300 ° C. in a non-oxidizing gas atmosphere. This eliminates the need for manufacturing equipment for high-temperature heating and simplifies the manufacturing process. Therefore, the phosphor according to the present embodiment can be easily manufactured.

  Next, the sintered body obtained by sintering the mixture is crushed and pulverized, and then washed with water or acid to remove unnecessary components. Thereby, a phosphor powder having a target composition is obtained.

The phosphor according to the present embodiment can be applied to a light emitting device including a light emitting element such as an LED. The light-emitting element is not particularly limited, but is preferably a light-emitting element that emits light having a main light emission peak in the range of 350 nm to 470 nm. A nitride semiconductor LED is mentioned as a preferable example of such a light emitting element. The nitride semiconductor in the nitride semiconductor LED is a compound semiconductor having a composition of, for example, In _x Ga _y Al _z N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1, x + y + z = 1). Examples of important specific examples of the nitride semiconductor include AlN, GaN, AlGaN, InGaN, and the like.

  When the nitride semiconductor LED emits violet light or near-ultraviolet light, the emission wavelength of the nitride semiconductor LED is 410 nm or less, and particularly when the emission wavelength is in the range of 365 nm to 410 nm, the nitride semiconductor LED is highly efficient. Emits light. When the nitride semiconductor LED emits blue light, the nitride semiconductor LED emits light with particularly high efficiency when the emission wavelength of the nitride semiconductor LED is in the range of 420 nm to 480 nm. Therefore, when the phosphor according to the present embodiment is applied to a light-emitting device including such a nitride semiconductor LED, the light-emitting efficiency of the light-emitting device is particularly high.

[Light emitting device]
The light emitting device according to this embodiment will be described. As shown in FIGS. 1 and 2, the light emitting device 1 includes an LED chip 10 that is a light emitting element, a mounting substrate 20, an optical member 60, a sealing portion 50, and a wavelength conversion member (color conversion member) 70. As will be described later, the wavelength conversion member (color conversion member) 70 includes phosphor particles formed from the phosphor according to the present embodiment.

  The LED chip 10 is mounted on the mounting substrate 20. The shape of the mounting substrate 20 is a rectangular plate shape in plan view. A pair of conductor layers 23 for supplying power to the LED chip 10 are formed on the first surface facing the thickness direction of the mounting substrate 20. Further, the LED chip 10 is mounted on the first surface. The LED chip 10 and the conductor layer 23 are electrically connected by a wire 14. The optical member 60 is a dome-shaped member, and is fixed on the first surface of the mounting substrate 20. The LED chip 10 is accommodated between the optical member 60 and the mounting substrate 20. The optical member 60 has a function of controlling the orientation of light emitted from the LED chip 10. The sealing part 50 is formed from a translucent sealing material. The sealing portion 50 is filled in a space surrounded by the optical member 60 and the mounting substrate 20. The sealing portion 50 seals the LED chip 10 and a plurality of (in this embodiment, two) wires 14. The wavelength conversion member 70 is formed in a dome shape so as to surround the optical member 60. When the LED chip 10 emits light, the phosphor particles in the wavelength conversion member 70 are excited by the light emitted from the LED chip 10 (excitation light), and fluorescent light having a wavelength longer than that of the excitation light (what is the emission color of the LED chip 10)? (Converted light consisting of light of different colors). Between the optical member 60 and the wavelength conversion member 70, a gap 80 in which a gas such as air is enriched is interposed. On the first surface of the mounting substrate 20, an annular weir 27 that surrounds the outer periphery of the optical member 60 is formed. The dam portion 27 is formed so as to protrude from the first surface. Therefore, when the optical member 60 is fixed to the mounting substrate 20, even if the sealing material overflows from the space surrounded by the optical member 60 and the mounting substrate 20, the sealing material is blocked by the dam portion 27. I can be dammed up.

  The main light emission peak of the LED chip 10 is preferably in the range of 350 nm to 470 nm. Examples of such an LED chip 10 include a GaN-based blue LED chip that emits blue light and a near-ultraviolet LED chip that emits near-ultraviolet light.

  In a GaN blue LED chip, an n-type SiC substrate having a lattice constant or crystal structure closer to that of GaN than a sapphire substrate and having conductivity is used as a crystal growth substrate. On the SiC substrate, for example, a light-emitting portion having a double hetero structure is formed. The light emitting portion is formed by, for example, an epitaxial growth method (for example, MOVPE method) using a GaN-based compound semiconductor material or the like as a raw material. The LED chip 10 includes a cathode electrode on the surface facing the first surface of the mounting substrate 20 and an anode electrode on the opposite surface. The cathode electrode and the anode electrode are constituted by, for example, a laminated film of a Ni film and an Au film. The material for the cathode electrode and the anode electrode is not particularly limited, and may be any material as long as good ohmic characteristics can be obtained. For example, Al may be used.

  The structure of the LED chip 10 is not limited to the above structure. For example, after a light emitting part or the like is formed by epitaxial growth on a crystal growth substrate, a support substrate such as an Si substrate that supports the light emitting part is fixed to the light emitting part, and then the crystal growth substrate is removed. The LED chip 10 may be formed.

  The mounting board 20 includes a rectangular heat transfer plate 21 and a wiring board 22. The heat transfer plate 21 is formed from a heat conductive material. The LED chip 10 is mounted on the heat transfer plate 21. The wiring board 22 is, for example, a rectangular flexible printed wiring board. The wiring board 22 is fixed on the heat transfer plate 21 via, for example, a polyolefin-based fixing sheet 29. A rectangular window hole 24 that exposes the mounting position of the LED chip 10 on the heat transfer plate 21 is formed at the center of the wiring board 22. Inside this window hole 24, the LED chip 10 is mounted on the heat transfer plate 21 via a submount member 30 described later. Therefore, the heat generated in the LED chip 10 is conducted to the submount member 30 and the heat transfer plate 21 without passing through the wiring board 22.

  The wiring board 22 includes an insulating base material 221 made of a polyimide film and a pair of conductor layers 23 for supplying power to the LED chip 10 formed on the insulating base material 221. Furthermore, the wiring board 22 includes a protective layer 26 that covers each conductor layer 23 and covers a portion of the insulating base material 221 where the conductor layer 23 is not formed. The protective layer 26 is formed of, for example, a white resist (resin) having light reflectivity. In this case, even if light is radiated from the LED chip 10 toward the wiring substrate 22, the light is reflected by the protective layer 26, thereby suppressing light absorption in the wiring substrate 22. Thereby, the light extraction efficiency from the LED chip 10 to the outside is improved, and the light output of the light emitting device is improved. Each conductor layer 23 is formed in an outer peripheral shape slightly smaller than half of the outer peripheral shape of the insulating base material 221. The insulating base material 221 may be formed of an FR4 substrate, an FR5 substrate, a paper phenol resin substrate, or the like.

  Each conductor layer 23 includes two terminal portions 231 each having a rectangular shape in plan view. The terminal portion 231 is located in the vicinity of the window hole 24 of the wiring board 22, and the wire 14 is connected to the terminal portion 231. Each conductor layer 23 further includes one external connection electrode portion 232 having a circular shape in plan view. The external connection electrode portion 232 is located near the outer periphery of the wiring board 22. The conductor layer 23 is composed of, for example, a laminated film of a Cu film, a Ni film, and an Au film.

  The protective layer 26 is patterned so that each conductor layer 23 is partially exposed from the protective layer 26. In the vicinity of the window hole 24 of the wiring board 22, the terminal portion 231 in each conductor layer 23 is exposed from the protective layer 26. Further, external connection electrode portions 232 in each conductor layer 23 are exposed from the protective layer 26 in the vicinity of the outer periphery of the wiring board 22.

  The LED chip 10 is mounted on the heat transfer plate 21 via the submount member 30 as described above. The submount member 30 relieves stress acting on the LED chip 10 due to a difference in linear expansion coefficient between the LED chip 10 and the heat transfer plate 21. The submount member 30 is formed in a rectangular plate shape having a size larger than the chip size of the LED chip 10.

  The submount member 30 has not only a function of relieving the stress but also a heat conduction function of conducting heat generated in the LED chip 10 in a wider range than the chip size of the LED chip 10 in the heat transfer plate 21. Yes. In the light emitting device 1 according to the present embodiment, the LED chip 10 is mounted on the heat transfer plate 21 via the submount member 30, so that the heat generated by the LED chip 10 passes through the submount member 30 and the heat transfer plate 21. In addition, the heat acting on the LED chip 10 due to the difference in linear expansion coefficient between the LED chip 10 and the heat transfer plate 21 is relieved.

  The submount member 30 is made of, for example, AlN having a relatively high thermal conductivity and an insulating property.

  The cathode electrode of the LED chip 10 is superposed on the submount member 30, and the cathode electrode is a wire composed of an electrode pattern (not shown) connected to the cathode electrode and a fine metal wire (for example, a gold fine wire, an aluminum fine wire, etc.). 14 is electrically connected to one of the two conductor layers 23. The LED chip 10 is electrically connected via a wire 14 to a conductor layer 23 that is not connected to the cathode electrode.

  For joining the LED chip 10 and the submount member 30, for example, solder such as SnPb, AuSn, SnAgCu, silver paste, or the like is used. It is particularly preferable to use lead-free solder such as AuSn or SnAgCu. When the submount member 30 is made of Cu and AuSn is used for bonding the LED chip 10 and the submount member 30, Au or Ag is previously formed on the surfaces of the submount member 30 and the LED chip 10 to be bonded to each other. It is preferable to perform a pretreatment for forming a metal layer made of For joining the submount member 30 and the heat transfer plate 21, for example, lead-free solder such as AuSn or SnAgCu is preferably used. When AuSn is used for joining the submount member 30 and the heat transfer plate 21, a pretreatment for forming a metal layer made of Au or Ag in advance on the surface of the heat transfer plate 21 to be joined with the submount member 30. Is preferably applied.

  The material of the submount member 30 is not limited to AlN, and any material may be used as long as the linear expansion coefficient is relatively close to 6H—SiC, which is the material for the crystal growth substrate, and the thermal conductivity is relatively high. For example, composite SiC, Si, Cu, CuW, or the like may be employed as the material of the submount member 30. Since the submount member 30 has the above-described heat conduction function, the area of the surface of the heat transfer plate 21 facing the LED chip 10 is the area of the surface of the LED chip 10 facing the heat transfer plate 21. It is desirable that it be sufficiently large.

  In the light emitting device 1 according to this embodiment, the heat transfer is larger than the dimension from the surface on the LED chip 10 side facing the thickness direction of the heat transfer plate 21 to the surface on the LED chip 10 side facing the thickness direction of the protective layer 26. The dimension from the surface of the plate 21 to the surface on the LED chip 10 side facing the thickness direction of the submount member 30 is larger. The thickness dimension of the submount member 30 is set so as to have such a positional relationship. For this reason, the light emitted from the LED chip 10 is suppressed from being absorbed by the wiring board 22 through the inside of the window hole 24 of the wiring board 22. Thereby, the light extraction efficiency from the LED chip 10 to the outside is further improved, and the light output of the light emitting device is further improved.

  Note that a reflective film that reflects light emitted from the LED chip 10 is formed around the position where the LED chip 10 is disposed on the surface of the submount member 30 facing the thickness direction of the LED chip 10. Good. In this case, the light emitted from the LED chip 10 is prevented from being absorbed by the submount member 30. Thereby, the light extraction efficiency from the LED chip 10 to the outside is further improved, and the light output of the light emitting device is further improved. The reflective film is composed of, for example, a laminated film of a Ni film and an Ag film.

  A silicone resin is mentioned as a sealing material which is a material for forming the above-mentioned sealing part 50. For example, an acrylic resin, glass, or the like may be used instead of the silicone resin.

  The optical member 60 is formed from a light transmissive material (eg, silicone resin, glass, etc.). In particular, when the optical member 60 is formed of a silicone resin, a difference in refractive index and a difference in linear expansion coefficient between the optical member 60 and the sealing portion 50 can be reduced.

  The light emission surface 602 (surface facing the side opposite to the LED chip 10) of the optical member 60 is light emitted from the light incident surface 601 (surface facing the LED chip 10 side) into the optical member 60. A convex curved surface is formed so as not to be totally reflected at the boundary between the surface 602 and the gap 80. The optical member 60 is disposed so that the optical axis of the LED chip 10 coincides. Therefore, the light emitted from the LED chip 10 and incident on the light incident surface 601 of the optical member 60 can easily reach the wavelength conversion member 70 without being totally reflected at the boundary between the light emitting surface 602 and the gap layer 80. The total luminous flux emitted from the light emitting device increases. The optical member 60 is formed to have a uniform thickness along the normal direction regardless of the position.

  The wavelength conversion member 70 has a light incident surface 701 (a surface facing the LED chip 10) formed in a shape along the light emitting surface 602 of the optical member 60. Therefore, regardless of the position of the light emitting surface 602 of the optical member 60, the distance between the light emitting surface 602 of the optical member 60 and the wavelength conversion member 70 in the normal direction is a substantially constant value. The wavelength conversion member 70 is formed so that the thickness along the normal direction is uniform regardless of the position. The wavelength conversion member 70 is fixed to the mounting substrate 20 with, for example, an adhesive (for example, silicone resin, epoxy resin).

  Light emitted from the LED chip 10 enters the wavelength conversion member 70 from the light incident surface 701, and goes out of the wavelength conversion member 70 through the light emission surface (surface opposite to the LED chip 10) 702 of the wavelength conversion member 70. Emitted. When light passes through the wavelength conversion member 70, a part of this light is wavelength-converted by the phosphor particles in the wavelength conversion member 70. Thereby, light of a color corresponding to the combination of the light emitted from the LED chip 10 and the type of phosphor particles in the wavelength conversion member 70 is emitted from the light emitting device 1.

  The wavelength conversion member 70 includes a translucent medium constituting the parent phase and a plurality of phosphor particles dispersed in the translucent medium. At least a part of the phosphor particles is formed from the phosphor according to the present embodiment.

  The wavelength conversion member 70 contains phosphor particles other than the phosphor particles formed from the phosphor according to the present embodiment together with the phosphor particles formed from the phosphor according to the present embodiment as the phosphor particles. Also good.

When the light emitting device 1 emits white light and the LED chip 10 in the light emitting device 1 is a blue LED chip that emits blue light, for example, the wavelength conversion member 70 is a phosphor particle, and the phosphor according to the present embodiment. Together with green phosphor particles formed from In this case, the blue light emitted from the LED chip 10 without wavelength conversion and the light converted in wavelength by the red phosphor particles and the green phosphor particles in the wavelength conversion member 70 are emitted from the wavelength conversion member 70. The Thereby, white light is emitted from the light emitting device 1. The phosphors constituting the red phosphor particles in this case include (Ca, Sr) ₂ Si ₅ N ₈ : Eu ²⁺ , (Ca, Sr) AlSiN ₃ : Eu ²⁺ , CaS: Eu ^2+, etc. A phosphor having Other green phosphor particles may be used in combination with the green phosphor particles formed from the phosphor according to the present embodiment. In this case, as the phosphor constituting the green phosphor particles formed from the phosphor other than the phosphor according to the present embodiment, (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ , Y ₃ Al ₅ O ₁₂ : Compositions such as Ce ³⁺ , (Ba, Sr, Ca) Si ₂ O ₂ N ₂ : Eu ²⁺ , (Ca, Mg) ₃ Sc ₂ Si ₃ O ₁₂ : Ce ³⁺ , CaSc ₂ O ₄ : Ce ³⁺ A phosphor having The method of selecting phosphor particles for emitting white light from the light emitting device 1 is not limited to the above example. For example, the wavelength conversion member 70 may contain a green phosphor formed from the phosphor according to the present embodiment, yellow phosphor particles, and orange phosphor particles.

In the case where the light emitting device 1 emits white light, when the LED chip 10 in the light emitting device 1 is an ultraviolet LED chip that emits ultraviolet light, the wavelength conversion member 70 is used as phosphor particles, for example, the fluorescence according to the present embodiment. Along with green phosphor particles formed from the body, red phosphor particles and blue phosphor particles are contained. The phosphors constituting the red phosphor particles in this case are La ₂ O ₂ S: Eu ³⁺ , (Ca, Sr) ₂ Si ₅ N ₈ : Eu ²⁺ , (Ca, Sr) AlSiN ₃ : Eu ^2. Examples thereof include phosphors having a composition such as ⁺ . As phosphors constituting the blue phosphor particles, BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , (Sr, Ca, Ba) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , Sr ₃ MgSi ₂ O ₈ : Eu ² Examples thereof include phosphors having a composition such as ⁺ . Other green phosphor particles may be used in combination with the green phosphor particles formed from the phosphor according to the present embodiment. In this case, (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ , BaMgAl ₁₀ O ₁₇ : Eu ² are the phosphors constituting the green phosphor particles formed from the phosphors other than the phosphor according to the present embodiment. Examples include phosphors having compositions such as ⁺ , Mn ²⁺ , (Ba, Sr, Ca) Si ₂ O ₂ N ₂ : Eu ²⁺ .

  The particle diameter of the phosphor particles is not particularly limited, but the larger the average particle diameter of the phosphor particles, the smaller the defect density in the phosphor particles, the less energy loss during light emission, and the higher the light emission efficiency. For this reason, from the viewpoint of improving luminous efficiency, the average particle diameter of the phosphor particles is preferably 1 μm or more, more preferably 5 μm or more. This average particle diameter is a value measured by a laser diffraction / scattering particle size distribution measuring apparatus.

  The phosphor particles are subjected to appropriate surface treatment such as coating in order to suppress reflection of excitation light and fluorescence at the interface between the phosphor particles and the translucent medium in the wavelength conversion member 70. May be.

  The refractive index of the translucent medium constituting the parent phase of the wavelength conversion member 70 is preferably close to the refractive index of the phosphor particles, but is not limited thereto. Examples of the material of the translucent medium include a silicon compound having a siloxane bond and glass. Since these materials are excellent in heat resistance and light resistance (durability to light having a short wavelength such as blue to ultraviolet light), a light-transmitting medium is obtained by light in a wavelength range from blue light to ultraviolet light, which is excitation light of phosphor particles. Is prevented from deteriorating. Examples of silicon compounds include composites formed by crosslinking a silicone resin, a hydrolyzed condensate of organosiloxane, a condensate of organosiloxane, etc. by a known polymerization method (addition polymerization such as hydrosilylation, radical polymerization, etc.). Resin. As the translucent medium, for example, an acrylic resin or an organic / inorganic hybrid material formed by mixing and bonding an organic component and an inorganic component at the nm level or molecular level may be employed.

  The content of the phosphor particles in the wavelength conversion member 70 is appropriately determined in consideration of the types of the phosphor particles and the translucent medium, the dimensions of the wavelength conversion member 70, the wavelength conversion capability required for the wavelength conversion member 70, and the like. However, it is in the range of 5% by mass to 30% by mass, for example.

  When the wavelength conversion member 70 is irradiated with the excitation light of the phosphor particles, the phosphor particles absorb the excitation light and emit fluorescence having a wavelength longer than that of the excitation light. Thereby, when light is transmitted through the wavelength conversion member 70, the wavelength of this light is converted by the phosphor particles.

[Examples 1 to 4]
(Production of phosphor)
A phosphor represented by the composition formula Rb (Ba _1-a Eu _a ) ScSi ₃ O ₉ was produced as follows.

Rb ₂ CO ₃ powder, BaCO ₃ powder, Eu ₂ O ₃ powder, Sc ₂ O ₃ powder, and SiO ₂ powder are blended in proportions according to the target composition and mixed by ball milling. A powder was obtained. This mixed powder was put into an alumina crucible and pre-baked by heating at 1100 ° C. for 12 hours in the air. The sintered body formed by this preliminary firing was pulverized to obtain a powder. This powder was put into an alumina crucible and subjected to main calcination by heating at 1150 ° C. for 12 hours in a nitrogen / hydrogen mixed gas atmosphere having a hydrogen concentration of 5%. The sintered body formed by the main firing was pulverized to obtain phosphor particles.

  The composition formula of the phosphor in each example is as shown in Table 1 below.

(Evaluation)
The powder X-ray diffraction measurement using the CuKα ray of the phosphor obtained in each example was performed. The result is shown in FIG. For reference, FIG. 3 also shows a diffraction intensity curve of RbBaScSi ₃ O ₉ obtained by simulation.

  An emission spectrum of fluorescence emitted from the phosphor obtained in each example and an excitation spectrum of the phosphor were measured. As a measuring device, a spectrofluorometer FP-6500 manufactured by JASCO Corporation was used. The wavelength of excitation light applied to the phosphor during measurement of the fluorescence spectrum was 450 nm. The monitor wavelength at the time of measuring the excitation spectrum was the peak wavelength in the emission spectrum. FIG. 4 shows the emission spectrum (solid line) and excitation spectrum (broken line) of the phosphor obtained in each example.

  As a result, the emission spectrum of the phosphor obtained in each example has a sharp emission peak in the green range, and the absorption spectrum of the phosphor has a high intensity in a wide wavelength range shorter than the green range. Indicated.

[Examples 2, 5 to 8]
(Production of phosphor)
Rb ₂ CO ₃ powder, BaCO ₃ powder, SrCO ₃ powder, Eu ₂ O ₃ powder, Sc ₂ O ₃ powder, and SiO ₂ powder are blended in proportions according to the target composition, and these are mixed by a ball mill. Thus, a mixed powder was obtained. This mixed powder was put into an alumina crucible and pre-baked by heating at 1100 ° C. for 12 hours in the air. The sintered body formed by this preliminary firing was pulverized to obtain a powder. This powder was put into an alumina crucible and subjected to main calcination by heating at 1150 ° C. for 12 hours in a nitrogen / hydrogen mixed gas atmosphere having a hydrogen concentration of 5%. The sintered body formed by the main firing was pulverized to obtain phosphor particles.

  The composition formula of the phosphor in each example is as shown in Table 2 below.

(Evaluation)
Powder X-ray diffraction measurement using the CuKα ray of the phosphors obtained in Example 6 and Example 8 was performed. The result is shown in FIG. For reference, FIG. 5 also shows a diffraction intensity curve of RbBaScSi ₃ O ₉ obtained by simulation.

  An emission spectrum of fluorescence emitted from the phosphor obtained in each example and an excitation spectrum of the phosphor were measured. As a measuring device, a spectrofluorometer FP-6500 manufactured by JASCO Corporation was used. The wavelength of excitation light applied to the phosphor during measurement of the fluorescence spectrum was 450 nm. The monitor wavelength at the time of measuring the excitation spectrum was the peak wavelength in the emission spectrum. FIG. 6 shows the emission spectrum (solid line) and excitation spectrum (broken line) of the phosphor obtained in each example.

  As a result, the emission spectrum of the phosphor obtained in each example has a sharp emission peak in the green range, and the absorption spectrum of the phosphor has a high intensity in a wide wavelength range shorter than the green range. Indicated.

[Examples 9 to 13]
(Production of phosphor)
Rb ₂ CO ₃ powder, Na ₂ CO ₃ powder, K ₂ CO ₃ powder, BaCO ₃ powder, Eu ₂ O ₃ powder, Sc ₂ O ₃ powder, and SiO ₂ powder are blended in proportions according to the target composition These were mixed with a ball mill to obtain a mixed powder. This mixed powder was put into an alumina crucible and pre-baked by heating at 1100 ° C. for 12 hours in the air. The sintered body formed by this preliminary firing was pulverized to obtain a powder. This powder was put into an alumina crucible and subjected to main calcination by heating at 1150 ° C. for 12 hours in a nitrogen / hydrogen mixed gas atmosphere having a hydrogen concentration of 5%. The sintered body formed by the main firing was pulverized to obtain phosphor particles.

  The composition formula of the phosphor in each example is as shown in Table 3 below.

(Evaluation)
Powder X-ray diffraction measurement using the CuKα ray of the phosphors obtained in Examples 9 to 13 was performed. The results for Examples 9 and 10 are shown in FIG. 7, and the results for Examples 11 to 13 are shown in FIG. For reference, FIGS. 7 and 8 also show diffraction intensity curves of RbBaScSi ₃ O ₉ obtained by simulation.

  An emission spectrum of fluorescence emitted from the phosphor obtained in each example and an excitation spectrum of the phosphor were measured. As a measuring device, a spectrofluorometer FP-6500 manufactured by JASCO Corporation was used. The wavelength of excitation light applied to the phosphor during measurement of the fluorescence spectrum was 450 nm. The monitor wavelength at the time of measuring the excitation spectrum was the peak wavelength in the emission spectrum. The emission spectrum (solid line) and excitation spectrum (broken line) of the phosphors obtained in Examples 9 and 10 are shown in FIG. 9, and the emission spectrum (solid line) and excitation spectrum (broken line) of the phosphors obtained in Examples 11 to 13 are shown in FIG. ) Are shown in FIG.

  As a result, the emission spectrum of the phosphor obtained in each example has a sharp emission peak in the green range, and the absorption spectrum of the phosphor has a high intensity in a wide wavelength range shorter than the green range. Indicated.

[Examples 14 to 17]
(Production of phosphor)
Li ₂ CO ₃ powder, Na ₂ CO ₃ powder, K ₂ CO ₃ powder, BaCO ₃ powder, SrCO ₃ powder, CaCO ₃ powder, Eu ₂ O ₃ powder, Sc ₂ O ₃ powder, and SiO ₂ powder The mixture powder was obtained by blending at a ratio according to the composition to be mixed and mixing them with a ball mill. This mixed powder was put into an alumina crucible and pre-baked by heating at 1100 ° C. for 12 hours in the air. The sintered body formed by this preliminary firing was pulverized to obtain a powder. This powder was put into an alumina crucible and subjected to main calcination by heating at 1150 ° C. for 12 hours in a nitrogen / hydrogen mixed gas atmosphere having a hydrogen concentration of 5%. The sintered body formed by the main firing was pulverized to obtain phosphor particles.

  The composition formula of the phosphor in each example is as shown in Table 4 below.

(Evaluation)
Powder X-ray diffraction measurement using the CuKα ray of the phosphors obtained in Examples 14 to 17 was performed.

  Moreover, the emission spectrum of the fluorescence emitted from the phosphor obtained in each example and the excitation spectrum of this phosphor were measured. As a measuring device, a spectrofluorometer FP-6500 manufactured by JASCO Corporation was used. The wavelength of excitation light applied to the phosphor during measurement of the fluorescence spectrum was 450 nm. The monitor wavelength at the time of measuring the excitation spectrum was the peak wavelength in the emission spectrum.

  About Example 14, the result of a powder X-ray-diffraction measurement is shown in FIG. 11, and the measurement result of an emission spectrum (solid line) and an excitation spectrum (dashed line) is shown in FIG. Moreover, about Example 15, the result of a powder X-ray-diffraction measurement is shown in FIG. 13, and the measurement result of an emission spectrum (solid line) and an excitation spectrum (dashed line) is shown in FIG. Moreover, about Example 16, the result of a powder X-ray-diffraction measurement is shown in FIG. 15, and the measurement result of an emission spectrum (solid line) and an excitation spectrum (dashed line) is shown in FIG. Moreover, about Example 17, the result of a powder X-ray-diffraction measurement is shown in FIG. 17, and the measurement result of an emission spectrum (solid line) and an excitation spectrum (dashed line) is shown in FIG.

  As a result, the emission spectrum of the phosphor obtained in each example has a sharp emission peak in the green range, and the absorption spectrum of the phosphor has a high intensity in a wide wavelength range shorter than the green range. showed that.

1 Light Emitting Device 70 Wavelength Conversion Member

Claims (8)

A phosphor represented by the following composition formula (1).
A (M _1-a Eu _a ) LSi ₃ O ₉ (1)
(A is one or more elements selected from Li, Na, K and Rb. M is one or more elements selected from Ca, Sr and Ba. L is Ga, Al, Sc, Y, La, Gd. And one or more elements selected from Lu. A is a number satisfying 0.001 ≦ a ≦ 0.3.)   The phosphor according to claim 1, wherein L in the composition formula (1) includes Sc.   The phosphor according to claim 1 or 2, wherein M in the composition formula (1) includes at least one of Ba and Sr.   The phosphor according to any one of claims 1 to 3, wherein A in the composition formula (1) includes Rb. The phosphor according to any one of claims 1 to 4, which is represented by the following composition formula (2).
Rb (Ba _1-a Eu _a ) ScSi ₃ O ₉ (2)   The phosphor according to any one of claims 1 to 4, wherein A in the composition formula (1) includes K.   A light emitting device comprising: a light emitting element; and a wavelength converting member that emits light by absorbing light emitted from the light emitting element, wherein the wavelength converting member comprises the phosphor according to any one of claims 1 to 6. apparatus.   The light emitting device according to claim 7, wherein a main light emission peak of light emitted from the light emitting element is in a range of 350 nm to 470 nm.

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