JP5604482B2 - Light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device which emits a high luminous flux of high color rendering properties, especially, a light-emitting device which emits warm white light.SOLUTION: The light-emitting device includes a luminous element and a phosphor layer. The luminous element is a blue luminous element that emits light which has the luminescence peak in a wavelength region of 440 nm or more and less than 500 nm. The phosphor layer includes: a green phosphor which contains Euor Ceas the emission major ions; and a red phosphor of a nitride or an oxynitride containing Euas the emission major ions. The green phosphor and the red phosphor emit light by being excited by the light emitted by the blue luminous element. The light-emitting device outputs light which includes light components emitted from the green phosphor, the red phosphor and the blue luminous element. The green phosphor has the excitation peak at the shorter wavelength side than the excitation wavelength which is the peak of the light emitted by the blue luminous element. The red phosphor is a nitride-aluminosilicate-based red phosphor.

Description

  The present invention relates to a light emitting device formed by combining a nitride phosphor and a light emitting element, and more particularly to a light emitting device that emits, for example, warm white light.

Conventionally, a CaSiN ₂ : Eu ²⁺ phosphor having an emission peak in a wavelength region near 630 nm is known as a nitride phosphor emitting red light. This phosphor has an excitation spectrum peak in a wavelength region near 370 nm and emits high-power red light by excitation with near ultraviolet light to violet light in a wavelength region of 360 nm to less than 420 nm. Application to a light-emitting device combined with a light-emitting element that emits light to violet light is promising (see Non-Patent Document 1, for example). In addition to the CaSiN ₂ : Eu ²⁺ phosphor, for example, a Sr ₂ Si ₅ N ₈ : Eu ²⁺ phosphor (see, for example, Patent Document 1) is found as a nitride phosphor that emits red light. Has been.

In addition, as a phosphor having a light emission peak in a green to yellow to orange region having a wavelength of 500 nm or more and less than 600 nm, a nitride phosphor, an oxynitride phosphor, and an alkaline earth metal orthosilicic acid containing Eu ^{2+ in the} emission center ion Salt phosphors and the like are known. These phosphors have an excitation peak in a wavelength region near 400 nm, and emit high-power green to yellow to orange light by excitation with the above-described near ultraviolet light to violet light. For this reason, the application to the light-emitting device combined with the light emitting element which emits the said near-ultraviolet light-purple light is seen as promising. Furthermore, as phosphors having an emission peak in the above wavelength region, thiogallate phosphors containing Eu ^{2+ in the} emission center ion, and phosphors having a garnet structure containing Ce ³⁺ are also known (for example, Patent Documents). 2-7).

  On the other hand, conventionally, a light emitting element having an emission peak in the near ultraviolet to violet region having a wavelength of 360 nm or more and less than 420 nm (hereinafter referred to as a violet light emitting element), or a light emitting element having an emission peak in a blue region having a wavelength of 420 nm or more and less than 500 nm. There is known a light-emitting device that combines a blue light-emitting element (hereinafter referred to as a blue light-emitting element) and a phosphor that is excited by light emitted from the light-emitting element (see, for example, Patent Documents 6 and 7).

For a light emitting device that uses the violet light emitting element and achieves both high luminous flux and high color rendering, La ₂ O ₂ S: Eu ³⁺ phosphor and Y ₂ O are used as light emitting devices that emit warm white light. There is a light-emitting device that frequently uses oxysulfide phosphors that emit red light, such as ₂ S: Eu ³⁺ phosphors. In addition, as a light emitting device that emits white light, a light emitting device that uses a combination of the oxysulfide phosphor and a phosphor that emits green to yellow to orange light, or a light emitting device that combines a phosphor that emits blue light. There is also a device. As the phosphor that emits green to yellow to orange light, alkaline earth metal orthosilicate phosphor or zinc sulfide phosphor activated by Eu ²⁺ is used, and the phosphor that emits blue light is used. as is activated with halophosphate phosphor activated with aluminate phosphor and Eu ²⁺ in Eu ²⁺ or the like is used (for example, see Patent Document 7-9.).

In the light emitting device using the blue light emitting element, Sr ₂ Si ₅ N ₈ : Eu ² that emits red light as a light emitting device that emits warm white light and achieves both high luminous flux and high color rendering. ⁺ phosphor and CaS: light-emitting device is using Eu ²⁺ phosphor. There is also a light-emitting device using a combination of the red phosphor and another phosphor. Examples of the other phosphors include SrGa ₂ S ₄ : Eu ²⁺ green phosphor, SrAl ₂ O ₄ : Eu ²⁺ green phosphor and Y ₃ Al ₅ O ₁₂ : Ce ³⁺ yellow phosphor. (For example, refer to Patent Documents 10 and 11).

  As for the measurement technique of the internal quantum efficiency and the external quantum efficiency of the phosphor according to the present invention, a technique capable of measuring with high accuracy has already been established. The absolute value under irradiation with light of an excitation wavelength (under 254 nm ultraviolet light excitation) is known (for example, see Non-Patent Document 2).

Special table 2003-515665 gazette JP 2003-124527 A JP 2002-363554 A JP 2003-203504 A JP 2003-206481 A Japanese Patent Laid-Open No. 10-242513 International Publication No. 02/054502 Pamphlet International Publication No. 03/032407 Pamphlet JP 2003-110150 A Special table 2003-515655 gazette JP 2004-10786 A

Yuta Ueda et al., “Proceedings of the 71st Annual Conference of the Electrochemical Society of Japan”, Electrochemical Society, 2004, p. 75 Kazuaki Okubo et al., “Journal of the Illuminating Society”, 1999, Vol. 83, No. 2, p. 87

  However, there are currently few light emitting devices including the above-described light emitting elements and phosphors that achieve both high luminous flux and high color rendering. On the other hand, demands for light emitting devices are diversifying year by year, and in particular, development of light emitting devices that emit warm white light is expected.

  The present invention has been made to solve such problems, and provides a light-emitting device that achieves both high luminous flux and high color rendering properties, particularly a light-emitting device that emits warm-colored white light.

The present invention includes a light emitting element and a phosphor layer, the light emitting element is a blue light emitting element that emits light having an emission peak in a wavelength region of 440 nm or more and less than 500 nm, and the phosphor layer is 500 nm or more and less than 560 nm. A green phosphor containing Eu ²⁺ or Ce ³⁺ as an emission center ion, and an emission peak in a wavelength region of 600 nm or more and less than 660 nm, and Eu ²⁺ as an emission center ion. A nitride phosphor or an oxynitride red phosphor, wherein the green phosphor and the red phosphor emit light when excited by light emitted by the blue light emitting element, and the green phosphor and the red phosphor And a light emitting device including a light emitting component emitted from the blue light emitting element as output light, wherein the phosphor layer is substantially free of a phosphor other than a phosphor activated by Eu ²⁺ or Ce ^3+. , The green phosphor has an excitation peak on a shorter wavelength side than the excitation wavelength that is the peak of light emitted from the blue light-emitting element, and the red phosphor is a nitridoaluminosilicate-based red phosphor. Features.

  According to the present invention, it is possible to provide a light-emitting device that achieves both a high luminous flux and a high color rendering property, in particular, a light-emitting device that emits warm-colored white light.

It is sectional drawing of the semiconductor light-emitting device in embodiment of this invention. It is sectional drawing of the semiconductor light-emitting device in embodiment of this invention. It is sectional drawing of the semiconductor light-emitting device in embodiment of this invention. It is the schematic which shows the structure of the illumination and the display apparatus in embodiment of this invention. It is the schematic which shows the structure of the illumination and the display apparatus in embodiment of this invention. It is a perspective view of the illumination module in the embodiment of the present invention. It is a perspective view of the illumination module in the embodiment of the present invention. It is a perspective view of the illuminating device in embodiment of this invention. It is the side view A and bottom view B of the illuminating device in embodiment of this invention. 1 is a perspective view of an image display device in an embodiment of the present invention. It is a perspective view of the number display device in the embodiment of the present invention. SrSiN _2: is a graph showing the emission characteristics of Eu ²⁺ red phosphor. SrAlSiN _3: is a graph showing the emission characteristics of Eu ²⁺ red phosphor. Sr ₂ Si ₅ N _8: is a graph showing the emission characteristics of Eu ²⁺ red phosphor. _{(Ba, Sr) 2 SiO 4} : is a graph showing the emission characteristics of Eu ²⁺ green phosphor. _{(Sr, Ba) 2 SiO 4} : is a graph showing the emission characteristics of Eu ²⁺ yellow phosphor. _{(Sr, Ca) 2 SiO 4} : is a graph showing the emission characteristics of Eu ²⁺ yellow phosphor. _{0.75 (Ca 0.9 Eu 0.1) O} · 2.25AlN · 3.25Si 3 N 4: is a graph showing the emission characteristics of Eu ²⁺ yellow phosphor. _{(Y, Gd) 3 Al 5} O 12: is a graph showing the emission characteristics of Ce ³⁺ yellow phosphor. BaMgAl ₁₀ O _17: is a graph showing the emission characteristics of Eu ²⁺ blue phosphor. Sr ₄ Al ₁₄ O _25: is a graph showing the emission characteristics of Eu ²⁺ blue-green phosphor. _{(Sr, Ba) 10 (PO} 4) 6 Cl 2: is a graph showing the emission characteristics of Eu ²⁺ blue phosphor. La ₂ O ₂ S: is a diagram showing the emission characteristics of Eu ³⁺ red phosphor. It is a perspective view of the light-emitting device in Example 1 of this invention. It is a partial cross section figure of the light-emitting device in Example 1 of this invention. It is an emission spectrum of the light-emitting device in Example 1 of this invention. It is an emission spectrum of the light-emitting device in the comparative example 1 of this invention. It is a figure which shows the result of having simulated the relationship between correlation color temperature and a relative light beam in Example 1 and Comparative Example 1 of this invention. It is a figure which shows the result of having simulated the relationship between correlation color temperature and Ra in Example 1 and Comparative Example 1 of this invention. It is a figure which shows the result of having simulated the relationship between correlation color temperature and Ra in Example 2 of this invention. It is a figure which shows the result of having simulated the relationship between correlation color temperature and R9 in Example 2 of this invention. It is a figure which shows the result of having simulated the relationship between correlated color temperature and a relative light beam in Example 2 of this invention. It is an emission spectrum of the light-emitting device in Example 2 of this invention. It is an emission spectrum of the light-emitting device in Example 3 of this invention. It is an emission spectrum of the light-emitting device in the comparative example 2 of this invention. It is a figure which shows the result of having simulated the relationship between correlation color temperature and a relative light beam in Example 3 and Comparative Example 2 of this invention. It is a figure which shows the result of having simulated the relationship between the correlation color temperature of the light-emitting device using the ideal fluorescent substance in Example 3 and Comparative Example 2 of this invention, and a relative light beam. It is a figure which shows the result of having simulated the relationship between correlation color temperature and Ra in Example 3 and Comparative Example 2 of this invention. It is a figure which shows the result of having simulated the relationship between correlation color temperature and R9 in Example 3 and Comparative Example 2 of this invention. It is a figure which shows the result of having simulated the emission spectrum of the light-emitting device which emits the warm color type | system | group white light of correlation color temperature 4500K (duv = 0) in Example 3 of this invention. It is a figure which shows the result of having simulated the emission spectrum of the light-emitting device which emits the warm color type | system | group white light of correlation color temperature 5500K (duv = 0) in Example 3 of this invention.

When the characteristics of the phosphor activated by Eu ²⁺ were examined in detail, the phosphors shown in (1) to (3) below are purple having a light emission peak in the near ultraviolet to purple region having a wavelength of 360 nm or more and less than 420 nm. Not only the internal quantum efficiency under the excitation of the light emitting element but also the internal quantum efficiency under the excitation of a blue light emitting element having a light emission peak in the blue region with a wavelength of 420 nm or more and less than 500 nm, in particular, a wavelength of 440 nm or more and less than 500 nm is high and good. Was found to have an internal quantum efficiency of 90% to 100%.
(1) Alkaline earth metal orthosilicate type, thiogallate type, aluminate type and nitride type (nitridosilicate type and sialon) which are activated by Eu ²⁺ and have an emission peak in a wavelength region of 500 nm or more and less than 560 nm Green phosphors such as (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ , SrGa ₂ S ₄ : Eu ²⁺ , SrAl ₂ O ₄ : Eu ²⁺ , BaSiN ₂ : Eu ²⁺ , Sr _1.5 A phosphor such as Al ₃ Si ₉ N ₁₆ : Eu ²⁺ .
(2) Alkaline earth metal orthosilicate type, thiogallate type and nitride type (nitridosilicate type, sialon type, etc.) yellow that is activated by Eu ²⁺ and has an emission peak in the wavelength region of 560 nm to less than 600 nm Phosphor, for example, (Sr, Ba) ₂ SiO ₄ : Eu ²⁺ , CaGa ₂ S ₄ : Eu ²⁺ , 0.75 (Ca _0.9 Eu _0.1 ) O · 2.25AlN · 3.25Si ₃ N ₄ : Eu ²⁺ , Ca _1.5 Al ₃ Si ₉ N ₁₆ : Eu ²⁺ , (Sr, Ca) ₂ SiO ₄ : Eu ²⁺ , CaSiAl ₂ O ₃ N ₂ : Eu ²⁺ , CaSi ₆ AlON ₉ : Eu ^2+, etc. Phosphor.
(3) Nitride-based (nitridosilicate, nitridoaluminosilicate, etc.) red phosphors activated by Eu ²⁺ and having an emission peak in the wavelength region of 600 nm to less than 660 nm, for example, Sr ₂ Si ₅ Phosphors such as N ₈ : Eu ²⁺ , SrSiN ₂ : Eu ²⁺ , SrAlSiN ₃ : Eu ²⁺ , CaAlSiN ₃ : Eu ²⁺ , Sr ₂ Si ₄ AlON ₇ : Eu ²⁺ .

  The excitation spectrum of these phosphors has an excitation peak in the shorter wavelength region than the wavelength of light emitted by the blue light emitting device, most of which is in the near ultraviolet to purple region having a wavelength of 360 nm or more and less than 420 nm. The external quantum efficiency under excitation is not necessarily high. However, it has been found that the internal quantum efficiency is 70% or higher, which is higher than expected from the excitation spectrum, and 90% to 100% in particularly favorable cases.

As an example, FIG. 12 shows an internal quantum efficiency 16, an external quantum efficiency 17 and an excitation spectrum 18 of a SrSiN ₂ : Eu ²⁺ red phosphor, and an emission spectrum 19 of the phosphor is also shown for reference. 13 to 18 show SrAlSiN ₃ : Eu ²⁺ red phosphor (FIG. 13), Sr ₂ Si ₅ N ₈ : Eu ²⁺ red phosphor (FIG. 14), (Ba, Sr) ₂ SiO _4. : Eu ²⁺ green phosphor (FIG. 15), (Sr, Ba) ₂ SiO ₄ : Eu ²⁺ yellow phosphor (FIG. 16), (Sr, Ca) ₂ SiO ₄ : Eu ²⁺ yellow phosphor (FIG. 17) ), 0.75 (Ca _0.9 Eu _0.1 ) O · 2.25AlN · 3.25Si ₃ N ₄ : Eu ²⁺ yellow phosphor (FIG. 18) is shown in the same manner as FIG. For example, the external quantum efficiency of the (Sr, Ba) ₂ SiO ₄ : Eu ²⁺ yellow phosphor, which is an alkaline earth metal orthosilicate phosphor activated with Eu ²⁺ shown in FIG. 16, has a wavelength of 440 nm. And about 67% at a wavelength of 460 nm and about 60% at a wavelength of 470 nm. However, it was found that the internal quantum efficiency is 85% or higher, which is higher than expected from the excitation spectrum, in a blue region having a wavelength of 440 nm or more and less than 500 nm, and is about 94% when particularly good.

In addition to the phosphors described above, it has been found that phosphors activated with Eu ²⁺ or Ce ³⁺ have similar characteristics. As an example, FIGS. 19 to 22 show (Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ yellow phosphor (FIG. 19), BaMgAl ₁₀ O ₁₇ : Eu ²⁺ blue phosphor (FIG. 20), Sr _4. Al ₁₄ O ₂₅ : Eu ²⁺ blue-green phosphor (FIG. 21), (Sr, Ba) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ blue phosphor (FIG. 22) are shown in the same manner as FIG. .

  From FIG. 12 to FIG. 22, the excitation wavelength dependence of the external quantum efficiency of each phosphor is similar to the shape of the excitation spectrum. For example, under the excitation of light having a wavelength longer than the peak of the excitation spectrum, for example, the blue light emitting element It is understood that the external quantum efficiency is not necessarily a high value under the excitation of the blue light, but the internal quantum efficiency shows a high value even under the excitation of the blue light emitting element. Also, from FIGS. 12 to 18 and FIGS. 20 to 22, it can be seen that each phosphor has high internal quantum efficiency under excitation of the violet light-emitting element, and good ones are 90% to 100%.

Further investigation revealed that phosphors other than the above (1) to (3) have high internal quantum efficiencies under the excitation of the violet light emitting device, as shown in (4) and (5) below. It was.
(4) Nitride-based (nitridosilicate-based, sialon-based, etc.) blue-green or green phosphors activated by Eu ²⁺ or Ce ³⁺ and having an emission peak in the wavelength range of 490 nm to 550 nm, for example, Phosphors such as Sr ₂ Si ₅ N ₈ : Ce ³⁺ , SrSiAl ₂ O ₃ N ₂ : Eu ²⁺ , Ca _1.5 Al ₃ Si ₉ N ₁₆ : Ce ³⁺ .
(5) Alkaline earth metal orthosilicate-based, halophosphate-based blue-green or blue phosphor activated by Eu ²⁺ and having an emission peak in a wavelength region of 420 nm or more and less than 500 nm, for example, Ba ₃ MgSi ₂ Phosphors such as O ₈ : Eu ²⁺ , (Sr, Ca) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ .

  Since the excitation spectrum of these phosphors has an excitation peak in the near ultraviolet to violet region having a wavelength of 360 nm or more and less than 420 nm, the external quantum efficiency under excitation of the violet light emitting device is not high.

As an example, FIG. 23 shows an internal quantum efficiency 16, an external quantum efficiency 17, and an excitation spectrum 18 of a La ₂ O ₂ S: Eu ³⁺ red phosphor that has been conventionally used in combination with the violet light emitting element. For reference, an emission spectrum 19 of the phosphor is also shown. As can be seen from FIG. 23, the La ₂ O ₂ S: Eu ³⁺ red phosphor has an internal quantum efficiency and an external quantum efficiency of a purple region having an excitation spectrum peak of 380 nm to less than 420 nm, and about 360 to 380 nm. At the above excitation wavelength, it decreases rapidly as the excitation wavelength increases. For example, in the violet region where the excitation wavelength is 380 nm or more and less than 420 nm, when the excitation wavelength is gradually increased, the internal quantum efficiency is about 80% (380 nm), about 62% (400 nm), about 25% (420 nm), Large changes at low levels.

Although not shown, the internal quantum efficiency, external quantum efficiency, and excitation spectrum of Y ₂ O ₂ S: Eu ³⁺ red phosphor are the same as the internal quantum efficiency of La ₂ O ₂ S: Eu ³⁺ described above. The characteristics of quantum efficiency and excitation spectrum are shifted to the short wavelength side by 10 to 50 nm.

That is, La ₂ O ₂ S: Eu ³⁺ red phosphor and Y ₂ O ₂ S: Eu ³⁺ red phosphor, which are conventionally used in combination with the violet light-emitting element, have a wavelength of from 360 nm to less than 420 nm. It can be seen that it is difficult to convert the wavelength of light emitted from a light emitting element having a light emission peak in the violet region, particularly in a violet region having a wavelength of 380 nm to less than 420 nm, into red light with high conversion efficiency in terms of material properties.

Incidentally, the La ₂ O ₂ S: Eu ³⁺ red phosphor and Y ₂ O ₂ S: Eu ³⁺ red phosphor, exhibit an excitation wavelength dependence of the internal quantum efficiency described above, Eu ³⁺ charge When the state of movement (CTS: charge transfer state) is in the excited state, and light is emitted after the excitation energy has been relaxed to the 4f energy level of Eu ³⁺ via CTS, light is emitted with high efficiency, without passing through CTS. When light is emitted by direct excitation of Eu ³⁺ , this is because the light is not emitted with high efficiency. The CTS is a state in which one electron has moved from the surrounding negative ions (O or S) toward Eu ³⁺ . Therefore, due to the mechanism described above, it is difficult to obtain a light-emitting device with a high luminous flux using the oxysulfide-based red phosphor and a light-emitting element, particularly a violet light-emitting element.

  Furthermore, when a white light-emitting device that excites a plurality of types of phosphors using a purple light-emitting element is used, the intensity of the output light has the lowest internal quantum efficiency due to the balance of color balance. There is a correlation. That is, if there is at least one phosphor having a low internal quantum efficiency among the phosphors constituting the light emitting device, the intensity of the output light becomes low and white light with a high luminous flux cannot be obtained.

  Here, the internal quantum efficiency indicates the ratio of the quantum number of light emitted from the phosphor to the quantum number of the excitation light absorbed by the phosphor, and the external quantum efficiency irradiates the phosphor. The ratio of the quantum number of light emitted from the phosphor to the quantum number of excitation light is shown. That is, high quantum efficiency indicates that the excitation light is efficiently converted into light. A method for measuring quantum efficiency has already been established, and is detailed in Non-Patent Document 2 described above.

  The light emitted from the light emitting element absorbed by the phosphor having high internal quantum efficiency is efficiently converted and emitted. On the other hand, the light emitted from the light emitting element that is not absorbed by the phosphor is emitted as it is. Therefore, a light emitting device including a light emitting element having an emission peak in the above-described wavelength region and a phosphor having high internal quantum efficiency under excitation of light emitted from the light emitting element can efficiently use light energy. Therefore, by combining at least the phosphors (1) to (5) and the light emitting element, a light emitting device with a high luminous flux and a high color rendering can be obtained.

  On the other hand, a light emitting device including a light emitting element having a light emission peak in the above-described wavelength region and a phosphor having low internal quantum efficiency under excitation of light emitted from the light emitting element efficiently converts light energy emitted by the light emitting element. Since this is not possible, the light emitting device has a low luminous flux.

  Note that a light emitting device including a light emitting element having a light emission peak in the near ultraviolet to violet region of 360 nm or more and less than 420 nm and a phosphor having low external quantum efficiency under excitation of light emitted from the light emitting element has low visibility. In order to emit light in the near-ultraviolet to violet region, which is hardly involved in improving the luminous flux, increase the phosphor layer thickness, increase the phosphor concentration in the phosphor layer, etc. If it is not absorbed, the light emitting device has a low luminous flux.

  Embodiments of the present invention will be described below.

(Embodiment 1)
An example of the light-emitting device of the present invention includes a phosphor layer containing a nitride phosphor and a light-emitting element, and the light-emitting element has a light emission peak in a wavelength region of 360 nm or more and less than 500 nm, and the nitride phosphor is A light emitting device that emits light when excited by light emitted from the light emitting element and includes at least a light emitting component emitted by the nitride phosphor as output light. The nitride phosphor is a phosphor activated by Eu ²⁺ and represented by a composition formula (M _1-x Eu _x ) AlSiN _3, where M is Mg, Ca, Sr, It is at least one element selected from Ba and Zn, and the above x is a numerical value satisfying the formula 0.005 ≦ x ≦ 0.3.

  The light-emitting element is a photoelectric conversion element that converts electric energy into light, and has a light emission peak in any wavelength region of 360 nm to less than 420 nm, or 420 nm to less than 500 nm, more preferably 380 nm to less than 420 nm, or 440 nm to less than 500 nm. For example, a light emitting diode (LED), a laser diode (LD), a surface emitting LD, an inorganic electroluminescence (EL) element, an organic EL element, or the like can be used.

  When an LED or LD using a GaN-based compound as a light emitting layer is used as the light emitting element, it emits light in a wavelength region of preferably 380 nm to less than 420 nm, more preferably 395 nm to 415 nm, for high output. A violet light-emitting element that emits light having a peak, or a blue light-emitting element that emits light having an emission peak in a wavelength region of preferably 440 nm to less than 500 nm, more preferably 450 nm to 480 nm is preferable.

  The output light preferably includes a light emitting component emitted by the light emitting element. In particular, when the light-emitting element is a light-emitting element having a light emission peak in a blue region, higher color rendering can be achieved by including in the output light the light-emitting component emitted by the nitride phosphor and the light-emitting component emitted by the light-emitting element. White light having the property is obtained, which is more preferable.

The nitride phosphor, warm light in the wavelength region of less than 600 nm 660 nm, preferably above composition formula that emits red light having an emission peak in 650nm or less wavelength region above 610nm (M _1-x A nitride phosphor represented by Eu _x ) AlSiN ₃ and having a high internal quantum efficiency under the excitation light in the wavelength region of 360 nm or more and less than 500 nm, for example, SrAlSiN ₃ shown in FIG. It corresponds to Eu ²⁺ red phosphor and CaAlSiN ₃ : Eu ²⁺ red phosphor.

A light emitting device including at least a phosphor layer containing a nitride phosphor having high internal quantum efficiency and the light emitting element can efficiently output light energy. The light emitting device configured as described above is a device in which the intensity of the warm color light emitting component is high and the numerical value of the special color rendering index R9 is large. This is a combination of a conventional light emitting device using La ₂ O ₂ S: Eu ³⁺ phosphor and a combination of Sr ₂ Si ₅ N ₈ : Eu ²⁺ phosphor and YAG (yttrium, aluminum, garnet): Ce phosphor. It has a high luminous flux and a high color rendering property comparable to the conventional light emitting device used in the above.

  The light-emitting device of this embodiment is not particularly limited as long as it includes at least the phosphor layer containing the nitride phosphor and the light-emitting element. A white LED), a display device using a white LED, a lighting device using a white LED, and the like. More specifically, examples of the display device using the white LED include an LED information display terminal, an LED traffic signal lamp, and an automobile LED lamp. Illumination devices using white LEDs include, for example, LED indoor / outdoor illumination lights, vehicle interior LED lights, LED emergency lights, and LED decoration lights.

  Among these, the white LED is particularly preferable. Generally, a conventional LED is a light emitting element of a monochromatic light source that emits light of a specific wavelength because of its light emission principle. That is, a light emitting element that emits white light cannot be obtained from a conventional LED. On the other hand, the white LED of the present embodiment can obtain white fluorescence by a method of combining a conventional LED and a phosphor, for example.

  In the present embodiment, the nitride phosphor is more preferable when the main component of the element M is Sr or Ca, because a good color tone and strong emission intensity can be obtained. Note that the main component being Sr or Ca means that 50 atomic% or more of the element M is any one element of Sr or Ca. Moreover, it is preferable that 80 atomic% or more of the element M is any one element of Sr or Ca, and it is more preferable that all the atoms of the element M are any one element of Sr or Ca.

  The light-emitting element is preferably an injection type electroluminescence element because it emits strong output light. An injection-type electroluminescence device is a photoelectric conversion device that emits a fluorescent material by injecting electrons and holes by an electric field and recombining electron-hole pairs to convert electrical energy into light energy. Yes, for example, LED, LD, surface emitting LD, etc. In particular, it is more preferable to use an LED or LD including a GaN-based semiconductor in the active layer for the light-emitting element because strong and stable output light can be obtained.

(Embodiment 2)
As another example of the light emitting device of the present invention, the phosphor layer of Embodiment 1 described above is activated with Eu ²⁺ or Ce ³⁺ and has a light emission peak in a wavelength region of 500 nm or more and less than 560 nm. You may make it the structure further containing fluorescent substance. The green phosphor is excited by light emitted from the light-emitting element described in Embodiment 1, and has a wavelength region of 500 nm to less than 560 nm, preferably a wavelength region of 510 nm to 550 nm, more preferably a wavelength of 525 nm to 550 nm. The phosphor is not particularly limited as long as the phosphor emits light having an emission peak in the region.

  For example, when a blue light emitting device is used, a green phosphor whose excitation peak on the longest wavelength side of the excitation spectrum is not in the wavelength region of 420 nm or more and less than 500 nm, that is, in the wavelength region where the excitation peak on the longest wavelength side of the excitation spectrum is less than 420 nm. A certain green phosphor may be used.

The green phosphor is a phosphor having high internal quantum efficiency under the excitation light in the wavelength region of 360 nm or more and less than 500 nm, for example, (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ green phosphor shown in FIG. Etc. A light emitting device including at least a phosphor layer containing at least the phosphor and the light emitting element is preferable because it efficiently outputs light energy. In this light emitting device, the green light emission intensity included in the output light is increased, and the color rendering is improved. In addition, green light has high visibility and luminous flux is higher. In particular, depending on the combination of phosphors contained in the phosphor layer, it is possible to obtain output light having high color rendering properties with an average color rendering index (Ra) of 90 or more.

The green phosphor is a nitride phosphor or oxynitride phosphor activated with Eu ²⁺ , such as BaSiN ₂ : Eu ²⁺ , Sr _1.5 Al ₃ Si ₉ N ₁₆ : Eu ²⁺ , Ca _1.5 Al _{3. ^{Si 9 N 16: Eu 2+,}} CaSiAl 2 O 3 N 2: Eu 2+, SrSiAl 2 O 3 N 2: Eu 2+, CaSi 2 O 2 N 2: Eu 2+, SrSi 2 O 2 N 2: Eu ²⁺ , BaSi ₂ O ₂ N ₂ : Eu ^{2+ and the} like, alkaline earth metal orthosilicate phosphors activated with Eu ²⁺ , such as (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ , (Ba, Ca) ₂ SiO ₄ : Eu ^{2+ and the} like, thiogallate phosphors activated by Eu ²⁺ , such as SrGa ₂ S ₄ : Eu ²⁺ , and aluminate phosphors activated by Eu ²⁺ , such as SrAl ₂ O ₄ : Eu ^{2+ and the} like, aluminate phosphors co-activated with Eu ²⁺ and Mn ²⁺ , such as BaMgAl ₁₀ O ₁₇ : E A nitride phosphor or oxynitride phosphor activated by Ce ³⁺ such as u ²⁺ , Mn ²⁺ , for example, Sr ₂ Si ₅ N ₈ : Ce ³⁺ , Ca _1.5 Al ₃ Si ₉ N ₁₆ : Ce ³⁺ , Ca ₂ Si ₅ N ₈ : Ce ^{3+ and the} like, and phosphors having a garnet structure activated by Ce ³⁺ , such as Y ₃ (Al, Ga) ₅ O ₁₂ : Ce ³⁺ , Y ₃ Al ₅ O ₁₂ : Ce ³⁺ , BaY ₂ SiAl ₄ O ₁₂ : Ce ³⁺ , Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce ^3+, etc., the internal quantum efficiency under excitation of the light emitting device is increased. More preferred.

  Therefore, the light emitting device of the present embodiment includes a phosphor layer including at least the nitride phosphor of the first embodiment and the green phosphor, and the light emitting element of the first embodiment, and the red light emitted by the nitride phosphor. The light emitting device includes, in output light, a light emitting component of the system and a green light emitting component emitted from the green phosphor.

(Embodiment 3)
As yet another example of the light emitting device of the present invention, the phosphor layer of the first embodiment or the second embodiment is activated with Eu ²⁺ or Ce ³⁺ and is in a wavelength region of 560 nm or more and less than 600 nm. You may make it the structure which further contains the yellow fluorescent substance which has a luminescence peak. The yellow phosphor is a phosphor that is excited by light emitted from the light-emitting element described in Embodiment 1 and emits light having an emission peak in a wavelength region of 560 nm to less than 600 nm, preferably in a wavelength region of 565 nm to 580 nm. If it is, it will not be specifically limited.

  For example, when a blue light emitting element is used, the yellow phosphor whose excitation peak on the longest wavelength side of the excitation spectrum is not in the wavelength region of 420 nm or more and less than 500 nm, that is, the excitation peak on the longest wavelength side of the excitation spectrum is in the wavelength region of less than 420 nm. A certain yellow phosphor may be used.

The yellow phosphor is a phosphor having high internal quantum efficiency under the excitation light in the wavelength region of 360 nm or more and less than 500 nm, for example, (Sr, Ba) ₂ SiO ₄ : Eu ²⁺ yellow phosphor shown in FIG. (Sr, Ca) ₂ SiO ₄ : Eu ²⁺ yellow phosphor shown in FIG. 17, 0.75 (Ca _0.9 Eu _0.1 ) O · 2.25AlN · 3.25Si ₃ N ₄ : Eu shown in FIG. ²⁺ yellow phosphor and the like, and a phosphor having high internal quantum efficiency under excitation light in a wavelength region of 420 nm or more and less than 500 nm, for example, (Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ yellow shown in FIG. Corresponds to phosphor etc. A light emitting device including at least a phosphor layer containing at least the phosphor and the light emitting element is preferable because it efficiently outputs light energy. This light-emitting device can provide a light-emitting device that emits warm-colored or warm-colored light. In addition, yellow light has relatively high visibility and luminous flux is high. In particular, depending on the material design of the phosphor layer, it is possible to obtain output light having a high color rendering property with Ra of 90 or more.

The yellow phosphor is a nitride phosphor or oxynitride phosphor activated with Eu ²⁺ , for example, 0.75 (Ca _0.9 Eu _0.1 ) O · 2.25AlN · 3.25Si ₃ N ₄ : Eu ^{2 _{+, Ca 1.5 Al 3 Si 9}} N 16: Eu 2+, CaSiAl 2 O 3 N 2: Eu 2+, CaSi 6 AlON 9: Eu 2+ or the like, activated alkaline earth metal orthosilicate with Eu ²⁺ Salt phosphors such as (Sr, Ba) ₂ SiO ₄ : Eu ²⁺ , (Sr, Ca) ₂ SiO ₄ : Eu ^{2+ and the} like, thiogallate phosphors activated with Eu ²⁺ , such as CaGa ₂ S ₄ : When a phosphor having a garnet structure activated by Eu ²⁺ or the like and Ce ³⁺ , for example, (Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ or the like, the internal quantum under excitation of the light emitting element is used. Efficiency is increased, which is more preferable.

  Therefore, the light emitting device of the present embodiment includes a phosphor layer including at least the nitride phosphor of the first embodiment and the yellow phosphor, and the light emitting element of the first embodiment, and the red color emitted from the nitride phosphor. The light emitting device includes, in output light, a light emitting component of the system and a yellow light emitting component emitted from the yellow phosphor.

(Embodiment 4)
As still another example of the light emitting device of the present invention, light is emitted in a wavelength region of 420 nm or more and less than 500 nm activated by Eu ²⁺ on the phosphor layer described in any of Embodiments 1 to 3 described above. You may make it the structure which further contains the blue fluorescent substance which has a peak. The blue phosphor is excited by light emitted from the light-emitting element described in Embodiment 1, and emits light in a wavelength region of 420 nm or more and less than 500 nm, preferably in a wavelength region of 440 nm or more and 480 nm or less, in terms of color rendering properties and output. If it is the fluorescent substance which has a peak, it will not specifically limit. At this time, the light-emitting element is not particularly limited as long as it is the light-emitting element described in the first embodiment. However, if a violet light-emitting element is used, the range of selection of the phosphor material is widened, so Not only is the design easy, but even if the wavelength position of the light emitted by the light emitting element varies depending on the driving conditions such as the input power of the light emitting element, the influence on the output light is small.

The blue phosphor is a phosphor having high internal quantum efficiency under the excitation light in the wavelength region of 360 nm or more and less than 500 nm, preferably 360 nm or more and less than 420 nm, for example, BaMgAl ₁₀ O ₁₇ : Eu ²⁺ shown in FIG. Blue phosphor, Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ blue phosphor shown in FIG. 21, (Sr, Ba) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ blue phosphor shown in FIG. Applicable. A light emitting device including at least the phosphor layer containing the phosphor and the light emitting element is preferable because it efficiently outputs light energy. In this light emitting device, the blue light emission intensity contained in the output light is increased, the color rendering is improved, and the luminous flux is increased. In particular, depending on the material design of the phosphor layer, it is possible to obtain output light having a high color rendering property with Ra of 90 or more, and all the special color rendering indexes of R1 to R15 are 80 or more, preferably 85. As described above, in a more preferable case, it is possible to obtain 90 or more white output light close to sunlight. For example, BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , (Sr, Ba) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , Ba ₃ MgSi ₂ O ₈ : Eu ²⁺ , SrMgAl ₁₀ O ₁₇ : Eu ²⁺ , ( Sr, Ca) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , Ba ₅ SiO ₄ Cl ₆ : Eu ²⁺ , BaAl ₈ O _1.5 : Eu ²⁺ , Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ By using a blue phosphor or the like, output light having the above high color rendering properties and special color rendering index can be obtained.

Further, the blue phosphor may be a nitride phosphor or oxynitride phosphor activated with Eu ²⁺ , such as SrSiAl ₂ O ₃ N ₂ : Eu ²⁺ , alkaline earth activated with Eu ^2+. Metal silicate phosphors such as Ba ₃ MgSi ₂ O ₈ : Eu ²⁺ , Sr ₃ MgSi ₂ O ₈ : Eu ^{2+ and the} like, aluminate phosphors activated with Eu ²⁺ , such as BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , BaAl ₈ O ₁₃ : Eu ²⁺ , Sr ₄ Al ₁₄ O ₂₅ : Eu ^{2+ and the} like, and halophosphate phosphors activated with Eu ²⁺ , such as Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , (Sr, Ca) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , (Ba, Ca, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ The internal quantum efficiency under the excitation of the device is increased, which is more preferable.

In Embodiments 1 to 4, the phosphor contained in the phosphor layer is substantially free from phosphors other than the phosphor activated by Eu ²⁺ or Ce ³⁺ in order to obtain a high luminous flux. It is preferable to use a structure that does not substantially contain an inorganic phosphor other than the nitride phosphor or the oxynitride phosphor. When the phosphor is configured so as not to substantially contain a phosphor other than the phosphor activated by Eu ²⁺ or Ce ³⁺ , 90% by weight or more of the phosphor contained in the phosphor layer, preferably It means that the phosphor of 95 wt% or more, more preferably 98 wt% or more is a phosphor activated with Eu ²⁺ or Ce ³⁺ . In addition, the constitution containing substantially no inorganic phosphor other than nitride phosphor or oxynitride phosphor is 90% by weight or more, preferably 95% by weight or more of the phosphor contained in the phosphor layer. Preferably 98% by weight or more of the phosphor means a nitride phosphor or an oxynitride phosphor. The nitride phosphor and the oxynitride phosphor retain a relatively high internal quantum efficiency even under an operating temperature of 100 ° C. to 150 ° C. and an ambient temperature, and the wavelength peak of the emission spectrum is, for example, It does not shift to the short wavelength side like the aforementioned alkaline earth metal orthosilicate phosphor or phosphor having a garnet structure. For this reason, the light-emitting device having the above-described configuration is preferable because even if the input power is increased to increase the excitation light intensity or the light-emitting device is used in a high temperature atmosphere, the emission color variation is small and stable output light can be obtained.

  In order to obtain a light emitting device that emits a high luminous flux, among the phosphors substantially contained in the phosphor layer, the phosphor having the lowest internal quantum efficiency under the light excitation emitted by the light emitting element is the internal quantum efficiency ( A phosphor having an absolute value of 80% or more, preferably 85% or more, and more preferably 90% or more.

(Embodiment 5)
Still another example of the light-emitting device of the present invention includes a phosphor layer containing a phosphor and a light-emitting element, and the light-emitting element has a light emission peak in a wavelength region of 360 nm or more and less than 500 nm. A light-emitting device that emits light when excited by light emitted from the light-emitting element and includes at least a light-emitting component emitted from the phosphor as output light. Furthermore, the phosphor is activated with Eu ^2+, and a nitride phosphor or an oxynitride phosphor having an emission peak in the wavelength region of less than 600 nm 660 nm, it is activated by Eu ^2+, and And an alkaline earth metal orthosilicate phosphor having an emission peak in the wavelength region of 500 nm or more and less than 600 nm, and the internal quantum efficiency of these phosphors is 80% or more under light excitation emitted by the light emitting element.

  As the light-emitting element, the same light-emitting element as described in Embodiment Mode 1 can be used.

  The output light preferably includes a light emitting component emitted by the light emitting element. In particular, when the light-emitting element is a light-emitting element having a light emission peak in a blue wavelength region, higher color rendering can be achieved by including in the output light the light-emitting component emitted by the phosphor and the light-emitting component emitted by the light-emitting element. White light having the property is obtained, which is more preferable.

The nitride phosphor or oxynitride phosphor activated by Eu ²⁺ has a warm color light having an emission peak in a wavelength region of 600 nm or more and less than 660 nm, preferably an emission peak in a wavelength region of 610 nm or more and 650 nm or less. This phosphor emits red light having a high internal quantum efficiency under the excitation light in the wavelength region of 360 nm or more and less than 500 nm. More specifically, a nitride aluminosilicate phosphor represented by a composition formula (M _1-x Eu _x ) AlSiN ₃ , for example, SrAlSiN ₃ : Eu ²⁺ red phosphor or CaAlSiN ₃ : Eu ² shown in FIG. ⁺ Nitride silicate phosphors represented by the composition formula (M _1-x Eu _x ) SiN ₂ such as red phosphors, for example, SrSiN ₂ : Eu ²⁺ red phosphors and CaSiN ₂ : Eu ² shown in FIG. ⁺ Nitride silicate phosphor represented by the composition formula (M _1-x Eu _x ) ₂ Si ₅ N ₈ , such as Sr ₂ Si ₅ N ₈ : Eu ²⁺ red fluorescence shown in FIG. Body, Ca ₂ Si ₅ N ₈ : Eu ²⁺ red phosphor or Ba ₂ Si ₅ N ₈ : Eu ²⁺ red phosphor, etc., and a composition formula (M _1-x Eu _x ) ₂ Si ₄ AlON ₇ Oxonitridoaluminosilicate phosphors such as Sr ₂ Si ₄ AlON ₇ : Eu ²⁺ red phosphor or the like may be used. However, M in the composition formula is at least one element selected from Mg, Ca, Sr, Ba and Zn, and x is a numerical value satisfying the formula 0.005 ≦ x ≦ 0.3.

The alkaline earth metal orthosilicate phosphor is a phosphor activated with Eu ²⁺ and having an emission peak in a wavelength region of 500 nm or more and less than 600 nm, preferably 525 nm or more and less than 600 nm. Is a green phosphor having an emission peak in a wavelength region of 525 nm or more and less than 560 nm, more preferably in a wavelength region of 530 nm or more and 550 nm or less, such as (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ shown in FIG. A green phosphor or the like, or a yellow phosphor having an emission peak in a wavelength region of 560 nm or more and less than 600 nm, for example, (Sr, Ba) ₂ SiO ₄ : Eu ²⁺ yellow phosphor shown in FIG. 16, shown in FIG. and _{(Sr, Ca) 2 SiO 4} : Eu 2+ is yellow phosphor and the like, under excitation light in the wavelength region of less than 360nm or more 500nm described above Part quantum efficiency corresponds to a higher phosphor.

  The phosphors have an internal quantum efficiency of 80% or more, preferably 85% or more, more preferably 90% or more under light excitation emitted from the light-emitting element. As described above, the light emitting device including at least the phosphor layer including the phosphor having high internal quantum efficiency and the light emitting element can efficiently output light energy. In addition, a light-emitting device configured using the nitride phosphor or the oxynitride phosphor as described above has a high warm-colored light-emitting component intensity and a large special color rendering index R9.

  Further, the light emitting device having the above configuration does not use a sulfide-based phosphor having a problem in reliability, and uses an expensive nitride phosphor or oxynitride phosphor only for a red phosphor. Therefore, a white light source having a high luminous flux and a high color rendering can be provided, and the cost of a light emitting device such as a white light source can be reduced.

The light emitting device of the present embodiment includes the nitride phosphor or oxynitride phosphor activated by Eu ²⁺ and emitting red light, and the alkaline earth metal orthosilicate activated by Eu ^2+. There is no particular limitation as long as it includes at least a phosphor layer including a phosphor and the light-emitting element, and for example, the above-described white LED is applicable.

  In this embodiment, the nitride phosphor or oxynitride phosphor represented by the above composition formula can obtain a good color tone and strong emission intensity when the main component of the element M is Sr or Ca. More preferred. Note that the main component being Sr or Ca means that 50 atomic% or more of the element M is any one element of Sr or Ca. Moreover, it is preferable that 80 atomic% or more of the element M is any one element of Sr or Ca, and it is more preferable that all the atoms of the element M are any one element of Sr or Ca.

  The light-emitting element is preferably an injection type electroluminescence element because it emits strong output light. An injection-type electroluminescence device is a photoelectric conversion device that emits a fluorescent material by injecting electrons and holes by an electric field and recombining electron-hole pairs to convert electrical energy into light energy. Yes, for example, LED, LD, surface emitting LD, etc. In particular, it is more preferable to use an LED or LD including a GaN-based semiconductor in the active layer for the light-emitting element because strong and stable output light can be obtained.

The alkaline earth metal orthosilicate phosphor is activated by Eu ²⁺ and has a wavelength region of 500 nm to less than 560 nm, preferably a wavelength region of 525 nm to less than 560 nm, more preferably a wavelength region of 530 nm to 550 nm. It is preferable to use a green phosphor having an emission peak, such as (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ , (Ba, Ca) ₂ SiO ₄ : Eu ²⁺ . In the light emitting device using the green phosphor, the green emission intensity included in the output light is increased, and the color rendering is improved. In addition, green light has high visibility and luminous flux is higher. In particular, depending on the combination of phosphors contained in the phosphor layer, it is possible to obtain output light having a high color rendering property with an Ra of 90 or more.

Further, as the alkaline earth metal orthosilicate phosphor, a yellow phosphor activated with Eu ²⁺ having a light emission peak in a wavelength region of 560 nm to less than 600 nm, preferably in a wavelength region of 565 nm to 580 nm, For example, it is preferable to use (Sr, Ba) ₂ SiO ₄ : Eu ²⁺ . A light-emitting device using this yellow phosphor can provide a light-emitting device that emits warm-colored or warm-colored light, in particular, with enhanced yellow light emission intensity contained in output light and improved color rendering. In addition, yellow light has relatively high visibility and luminous flux is high. In particular, depending on the material design of the phosphor layer, it is possible to obtain output light having a high color rendering property with Ra of 90 or more. It is also preferable to use (Sr, Ca) ₂ SiO ₄ : Eu ²⁺ yellow phosphor that emits fluorescence close to that of the yellow phosphor.

  In the present embodiment, it is preferable that a nitride phosphor or an oxynitride phosphor is not substantially contained as a phosphor other than the above-described red phosphor contained in the phosphor layer. Thereby, the usage-amount of the nitride fluorescent substance or oxynitride fluorescent substance used for a light-emitting device can be minimized, and the reduction of the manufacturing cost of a light-emitting device can be aimed at. Further, it is preferable that a sulfide-based phosphor is not substantially contained as a phosphor other than the above-described red phosphor contained in the phosphor layer. Thereby, the reliability of the light-emitting device can be increased, and for example, a light-emitting device with little change over time such as deterioration can be provided.

In Embodiment 5 as well, the phosphor contained in the phosphor layer substantially does not contain any phosphor other than the phosphor activated by Eu ²⁺ or Ce ³⁺ in order to obtain a high luminous flux. A configuration is preferred. In addition, among the phosphors substantially contained in the phosphor layer, the internal quantum efficiency of the phosphor having the lowest internal quantum efficiency under excitation of light emitted from the light emitting element is preferably 80% or more.

  Hereinafter, an embodiment of a light emitting device of the present invention will be described with reference to the drawings.

  1, 2, and 3 are cross-sectional views of a semiconductor light emitting element showing an example of a light emitting device of the present invention.

  FIG. 1 shows a semiconductor light emitting device having a structure in which at least one light emitting device 1 is conductively mounted on a submount device 4 and sealed with a base material that also serves as a phosphor layer 3 including a phosphor 2. In FIG. 2, at least one light emitting element 1 is conductively mounted on a cup 6 provided on a mount lead of a lead frame 5, and a phosphor layer 3 including a phosphor 2 is provided in the cup 6. 1 shows a semiconductor light emitting device having a structure sealed with a sealing material 7 such as resin. FIG. 3 shows a chip-type semiconductor light-emitting device having a structure in which at least one light-emitting device 1 is conductively mounted in a housing 8 and a phosphor layer 3 including a phosphor 2 is further provided.

  1 to 3, a light-emitting element 1 is a photoelectric conversion element that converts electrical energy into light, and is 360 nm to less than 500 nm, preferably 380 nm to less than 420 nm, or 440 nm to less than 500 nm, more preferably 395 nm to 415 nm or less, or 450 nm or more. There is no particular limitation as long as it is a light emitting element that emits light having an emission peak in a wavelength region of 480 nm or less. For example, an LED, an LD, a surface emitting LD, an inorganic EL element, an organic EL element, or the like may be used. In particular, an LED or a surface emitting LD is preferable for increasing the output of the semiconductor light emitting device.

1 to 3, the phosphor layer 3 is a nitride phosphor represented by a composition formula (M _1-x Eu _x ) AlSiN ₃ as the phosphor 2, where M is Mg, Ca, Sr, It is at least one element selected from Ba and Zn, and x is constituted by dispersing at least a phosphor having a numerical value satisfying the expression 0.005 ≦ x ≦ 0.3.

  The material used for the base material of the phosphor layer 3 is not particularly limited, and generally transparent resin such as epoxy resin or silicon resin, low melting point glass, or the like may be used. For the purpose of providing a light-emitting device in which the emission intensity does not decrease with operating time, the base material is preferably a light-transmitting inorganic material such as silicon resin or low-melting glass, and more preferably the light-transmitting inorganic material. . For example, when the transparent resin is used for the base material of the phosphor layer 3, the content of the nitride phosphor is preferably 5 to 80% by weight, and more preferably 10 to 60% by weight. The nitride phosphor contained in the phosphor layer 3 absorbs part or all of the light emitted by the light emitting element 1 by driving and converts it into red light, so that at least a light emitting component emitted by the nitride phosphor is emitted. It is included as output light of the semiconductor light emitting device.

Further, when the phosphor 2 includes at least a nitride phosphor represented by the composition formula (M _1-x Eu _x ) AlSiN ₃ , the phosphor layer 3 further includes a phosphor other than the nitride phosphor. However, it does not have to be included. For example, the alkaline earth metal orthosilicate phosphor, nitride phosphor and acid activated by Eu ²⁺ or Ce ³⁺ and having high internal quantum efficiency under excitation light in a wavelength region of 360 nm or more and less than 500 nm are used. A nitride phosphor, aluminate phosphor, halophosphate phosphor, thiogallate phosphor or the like is used in the combinations shown in (1) to (6) below, and the light-emitting element 1 emits light in a wavelength region of 360 nm to less than 420 nm. When the violet light emitting element having a peak is used, the phosphor is excited with high efficiency by the light emitted from the light emitting element 1, and becomes, for example, a semiconductor light emitting element that emits white light due to the color mixture of the light emitted from the plurality of phosphors.
(1) A blue phosphor that emits light having an emission peak in a wavelength region of 420 nm to less than 500 nm, preferably 440 nm to less than 500 nm, and light having an emission peak in a wavelength region of 500 nm to less than 560 nm, preferably 510 nm to 550 nm A phosphor layer comprising a green phosphor that emits light, a yellow phosphor that emits light having an emission peak in a wavelength region of 560 nm to less than 600 nm, preferably 565 nm to 580 nm, and the nitride phosphor.
(2) A blue phosphor that emits light having an emission peak in a wavelength region of 420 nm or more and less than 500 nm, preferably 440 nm or more and less than 500 nm, and light having an emission peak in a wavelength region of 500 nm or more and less than 560 nm, preferably 510 nm or more and 550 nm or less. A phosphor layer comprising a green phosphor that emits light and the nitride phosphor.
(3) A blue phosphor that emits light having an emission peak in a wavelength region of 420 nm or more and less than 500 nm, preferably 440 nm or more and less than 500 nm, and light having an emission peak in a wavelength region of 560 nm or more and less than 600 nm, preferably 565 nm or more and 580 nm or less. A phosphor layer comprising a yellow phosphor that emits light and the nitride phosphor.
(4) A green phosphor that emits light having an emission peak in a wavelength region of 500 nm or more and less than 560 nm, preferably in a wavelength region of 525 nm or more and less than 560 nm, and a wavelength region of 560 nm or more and less than 600 nm, preferably 565 nm or more and 580 nm or less. A phosphor layer comprising a yellow phosphor that emits light having an emission peak in a wavelength region, and the nitride phosphor.
A phosphor layer comprising the yellow phosphor and the nitride phosphor.
(5) A phosphor layer containing the yellow phosphor and the nitride phosphor.
(6) A phosphor layer containing the green phosphor and the nitride phosphor.

When the phosphor is used in the combinations shown in (7) to (9) below and the light-emitting element 1 is a blue light-emitting element having an emission peak in a wavelength region of 420 nm or more and less than 500 nm, the light emitted from the light-emitting element 1 A semiconductor light emitting device that emits white light is obtained by color mixing with light emitted from the phosphor.
(7) A green phosphor that emits light having an emission peak in a wavelength region of 500 nm or more and less than 560 nm, preferably in a wavelength region of 525 nm or more and less than 560 nm, and a wavelength region of 560 nm or more and less than 600 nm, preferably 565 nm or more and 580 nm or less. A phosphor layer comprising a yellow phosphor that emits light having an emission peak in a wavelength region, and the nitride phosphor.
(8) A phosphor layer containing the yellow phosphor and the nitride phosphor.
(9) A phosphor layer containing the green phosphor and the nitride phosphor.

When the light emitting element is a blue light emitting element, the green phosphor and the yellow phosphor were activated with Eu ²⁺ alkaline earth metal orthosilicate phosphor activated with Eu ²⁺ . In addition to nitride phosphors or oxynitride phosphors, phosphors having a garnet structure activated by Ce ³⁺ (particularly YAG: Ce-based phosphors), thiogallate fluorescence activated by Eu ²⁺ It can be selected widely from the body. More specifically, for example, SrGa ₂ S ₄ : Eu ²⁺ green phosphor, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce ³⁺ green phosphor, Y ₃ Al ₅ O ₁₂ : Ce ³⁺ green Phosphor, BaY ₂ SiAl ₄ O ₁₂ : Ce ³⁺ green phosphor, Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce ³⁺ green phosphor, (Y, Gd) ₃ Al ₅ O ₁₂ : Ce ^{3 +} yellow phosphor Y ₃ Al ₅ O ₁₂ : Ce ³⁺ , Pr ³⁺ yellow phosphor, CaGa ₂ S ₄ : Eu ²⁺ yellow phosphor and the like can be used.

Alternatively, the phosphor layer 3 in FIGS. 1-3, the phosphor 2, and the nitride phosphor or oxynitride phosphor emits red light is activated with at least Eu ^2+, activated by Eu ²⁺ And an alkaline earth metal orthosilicate phosphor having an emission peak in any wavelength region of 500 nm or more and less than 560 nm or 560 nm or more and less than 600 nm.

  The phosphor layer 3 may use the base material of the phosphor layer 3 described above. In addition, since the phosphor 2 included in the phosphor layer 3 absorbs a part or all of the light emitted from the light emitting element 1 and converts it into light, the output light of the semiconductor light emitting element is a nitride phosphor or an acid. It includes at least a light emitting component emitted from the nitride phosphor and a light emitting component emitted from the alkaline earth metal orthosilicate phosphor.

Further, the phosphor 2, and the nitride phosphor or oxynitride phosphor is activated with Eu ²⁺ emitting red light, it is activated by Eu ^2+, and less than 500 nm 560nm or 560nm or 600nm than When the phosphor layer 3 includes the alkaline earth metal orthosilicate phosphor having an emission peak in any one of the wavelength regions of the above, the phosphor layer 3 is not limited to the nitride phosphor or the oxynitride phosphor, and the alkaline earth metal ortho. A phosphor other than the silicate phosphor may or may not be included.

  However, for the purpose of reducing the amount of nitride phosphors, oxynitride phosphors and sulfide phosphors used, other nitride phosphors, oxynitride phosphors and sulfide phosphors are not included. Is preferred.

For example, aluminate phosphors, halophosphate phosphors, etc. that are activated by Eu ²⁺ or Ce ³⁺ and have high internal quantum efficiency under excitation in a wavelength region of 360 nm or more and less than 500 nm, and the above (1 ) To (6) are used in combination with the phosphors described above, the phosphors are excited with high efficiency by the light emitted from the light emitting element 1, and the semiconductor light emission that emits white light by the color mixture of the light emitted from the plurality of phosphors. Become an element. Further, when the phosphors shown in the above (7) to (9) are used in combination, a semiconductor light emitting device that emits white light is obtained by color mixture of light emitted from the light emitting device 1 and light emitted from the phosphor.

  In the semiconductor light emitting device of the present embodiment, a phosphor having a high internal quantum efficiency but not necessarily an external quantum efficiency under excitation of the blue light emitting device is used. For example, light emitted from the blue light emitting device and light emitted from the phosphor When a desired white-colored light is to be obtained by mixing the colors, a relatively large number of phosphors are required. Therefore, in order to obtain desired white light, it is necessary to increase the thickness of the phosphor layer. On the other hand, when the thickness of the phosphor layer is increased, there is an advantage that a light emitting device with less color unevenness of white light is obtained.

  If the phosphor layer 3 has a multilayer or multilayer structure, and the phosphor layer includes the nitride phosphor or the oxynitride phosphor in a part of the layer, the light emitting device of the semiconductor light emitting device of the present embodiment This is preferable because emission color spots and output spots can be suppressed.

The nitride phosphor or oxynitride phosphor containing Eu ²⁺ as the emission center ion absorbs blue, green, and yellow visible light and converts it into red light. When the phosphor layer 3 containing a material phosphor is formed by mixing any one of a blue phosphor, a green phosphor, and a yellow phosphor with the nitride phosphor or the oxynitride phosphor, The light emission of the green and yellow phosphors is also absorbed, and the nitride phosphor or oxynitride phosphor emits red light. For this reason, control of the luminescent color of a light-emitting device becomes difficult for the reason on the manufacturing process of a fluorescent substance layer. In order to prevent this problem, the phosphor layer 3 has a multilayer or multilayer structure, and the layer closest to the main light output surface of the light emitting element 1 is a nitride phosphor or oxynitride phosphor that emits red light. It is preferable to prevent excitation by the emission of blue, green and yellow phosphors. The yellow phosphor activated by Eu ²⁺ or Ce ³⁺ is excited by blue light or green light, and the green phosphor activated by Eu ²⁺ or Ce ³⁺ is blue light. Therefore, when the phosphor layer 3 is formed by mixing a plurality of kinds of phosphors having different emission colors, the same problem as described above occurs. In order to solve this problem, the semiconductor light emitting device according to the present embodiment has a phosphor layer 3 having a multilayer or multilayer structure and emits light having a short wavelength to a layer far from the main light output surface of the light emitting element 1. It is preferable to constitute a layer containing

  The semiconductor light-emitting device of this embodiment has at least the light-emitting device and a nitride phosphor or oxynitride phosphor that has high internal quantum efficiency under excitation of the light-emitting device and efficiently converts excitation light into red light. A light emitting device that includes at least a red light emitting component emitted by the nitride phosphor or oxynitride phosphor in the output light, and has both a high luminous flux and high color rendering properties, In particular, the light emitting device emits warm white light. When the light emitting element is a blue light emitting element, the output light is a light emitting device further including a light emitting component emitted by the light emitting element.

  4 and 5 are schematic views of the configuration of the illumination / display device showing an example of the light-emitting device of the present invention. FIG. 4 shows an illumination / display device configured by using at least one semiconductor light emitting element 9 in which the phosphor layer 3 including the phosphor 2 described above and the light emitting element 1 are combined, and an output light 10 thereof. FIG. 5 shows an illumination / display device in which at least one light-emitting element 1 and a phosphor layer 3 including the above-described phosphor 2 are combined, and an output light 10 thereof. About the light emitting element 1 and the fluorescent substance layer 3, the thing similar to the case of the semiconductor light emitting element demonstrated previously can be used. The operation and effect of the illumination / display device having such a configuration is the same as that of the semiconductor light emitting element described above.

  FIGS. 6-11 is a figure which shows the specific example incorporating the illumination and the display apparatus which are the embodiment of the light-emitting device of this invention which was outlined in FIG.4 and FIG.5. FIG. 6 is a perspective view of the illumination module 12 having the integrated light emitting unit 11. FIG. 7 shows a perspective view of an illumination module 12 having a plurality of light emitting units 11. FIG. 8 is a perspective view of a table lamp type lighting device having a light emitting unit 11 and capable of ON-OFF control and light amount control by a switch 13. FIGS. 9A and 9B are a side view A and a bottom view B of a lighting device as a light source configured by using a screw-type base 14, a reflecting plate 15, and a lighting module 12 having a plurality of light emitting portions 11. FIG. 10 is a perspective view of a flat image display device including the light emitting unit 11. FIG. 11 is a perspective view of a segment-type number display device including the light emitting unit 11.

  The illumination / display device according to the present embodiment uses a phosphor having high internal quantum efficiency under excitation of the light-emitting element, and particularly uses a semiconductor light-emitting element having a strong red color component and good color rendering. Therefore, it becomes an illumination / display device that achieves both a high luminous flux and a particularly high color rendering property with a high intensity of the red light-emitting component, which are superior or superior to those of conventional illumination / display devices.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
In this example, a card-type illumination module light source shown in FIG. 24 was manufactured as a light emitting device, and the light emission characteristics were evaluated. 25 is a partial cross-sectional view of FIG.

  First, a method for manufacturing the semiconductor light emitting element 21 will be described. On a n-type Si wafer, GaInN is formed on a pair of n-electrode 23 and p-electrode 24 of a Si diode element (submount element) 22 originally formed in a matrix via a microbump 25. A blue LED chip 26 emitting light having a light emission peak near 470 nm was conductively mounted as a light emitting layer.

  Since the blue LED chip 26 is conductively mounted on each Si diode element 22 originally formed in a matrix, the blue LED chip 26 is also mounted in a matrix as a result.

  Subsequently, after the n-electrode 23 and the p-electrode 24 are connected to the n-electrode and the p-electrode of the blue LED chip 26, respectively, the phosphor containing the phosphor 2 around the blue LED chip 26 using a printing technique. Body layer 3 was formed. Further, the upper surface of the phosphor layer 3 was ground and flattened, and then individually cut and separated using a diamond cutter to form the semiconductor light emitting device 21.

  Next, on an aluminum metal substrate 27 (size 3 cm × 3 cm, thickness 1 mm), a first insulator thick film 28 (thickness 75 μm), a copper electrode 29 (thickness about 10 μm, width 0.5 mm), The second insulating thick film 30 (thickness 30 μm) and the electrode pads 31a and 31b (thickness of about 10 μm, total 64 pairs) were sequentially laminated to form the heat radiating multilayer substrate 32. The first insulator thick film 28 and the second insulator thick film 30 are made of an alumina-dispersed epoxy resin formed by thermocompression bonding. The copper electrode 29 is formed by patterning using an etching technique, and the electrode pads 31a and 31b are negative and positive electrodes for power feeding formed by an etching technique. A contact hole was provided in a part of the second insulator thick film 30, and the electrode pads 31 a and 31 b were formed so that power could be supplied through the copper electrode 29.

  Next, the semiconductor light emitting device 21 was placed at a predetermined position on the heat dissipating multilayer substrate 32. At this time, the back electrode (n electrode) 33 of the Si diode element 22 is fixedly connected to the electrode pad 31 a using Ag paste, and the bonding pad portion 35 on the p electrode 24 is connected to the electrode pad 31 b using Au wire 34. The semiconductor light emitting device 21 is formed so that it can be fed.

  Next, an aluminum metal reflector 36 having an inverted conical cylindrical grinding hole was bonded onto the heat dissipating multilayer substrate 32 using an adhesive. At this time, the semiconductor light emitting element 21 on the heat dissipation multilayer substrate 32 was formed so as to fit in the grinding hole of the aluminum metal reflector 36. Furthermore, a dome-shaped lens 37 using an epoxy resin was formed so as to wrap and cover the entire semiconductor light emitting element 21 and the grinding hole, and the light emitting device of Example 1 was obtained.

  FIG. 24 is a perspective view of the light emitting device according to the first embodiment. In Example 1, a card-type illumination module light source was manufactured using 64 semiconductor light emitting elements 21, and the light emission characteristics were evaluated.

  In Example 1, the semiconductor light emitting element 21 is driven by flowing a current of about 40 mA to each of two semiconductor light emitting element groups in which 32 semiconductor light emitting elements 21 are connected in series to the copper electrode 29, and about 80 mA in total. Output light was obtained. This output light is a mixed color light of the light emitted from the blue LED chip 26 and the light emitted from the phosphor contained in the phosphor layer 3 that is excited and emitted by this light. Furthermore, as the output light, arbitrary white light was obtained by appropriately selecting the kind and amount of the LED chip and the phosphor.

  Hereinafter, the phosphor layer 3 will be described in detail.

The phosphor layer 3 was formed by drying an epoxy resin added with a phosphor. In Example 1, as a phosphor, SrAlSiN ₃ : Eu ²⁺ red phosphor (center particle size: 2.2 μm, maximum internal quantum efficiency: 60%) having an emission peak near a wavelength of 625 nm and light emission near a wavelength of 555 nm Two types of (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ green phosphor having a peak (center particle size: 12.7 μm, maximum internal quantum efficiency: 91%) are used, and bisphenol A type liquid is used as an epoxy resin. A two-component mixed epoxy resin of an epoxy resin (main material) mainly composed of an epoxy resin and an epoxy resin (cured material) mainly composed of an alicyclic acid anhydride was used. SrAlSiN ₃ : Eu ²⁺ red phosphor and (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ green phosphor are mixed in a weight ratio of about 1:10, and the mixed phosphor and epoxy resin are in a weight ratio. The mixture was mixed at about 1: 3 (phosphor concentration = 25% by weight).

(Comparative Example 1)
Sr ₂ Si ₅ N ₈ : Eu ²⁺ red phosphor (center particle size: 1.8 μm, maximum internal quantum efficiency: 62%) having an emission peak at a wavelength of about 625 nm on the phosphor, and an emission peak at a wavelength of about 560 nm The card-type illumination module light source is the same as in Example 1 using two types of Y ₃ Al ₅ O ₁₂ : Ce ³⁺ yellow phosphor (center particle size: 17.6 μm, maximum internal quantum efficiency: 98%). It was prepared. As the phosphor layer 3, Sr ₂ Si ₅ N ₈ : Eu ²⁺ red phosphor and Y ₃ Al ₅ O ₁₂ : Ce ³⁺ yellow phosphor are mixed at a weight ratio of about 1: 6, and this mixed fluorescence The mixture of the body and the epoxy resin at a weight ratio of about 1:14 (phosphor concentration = 6.7% by weight) was used. Then, in the same manner as in Example 1, output light was obtained by passing a current through the semiconductor light emitting element, and the light emission characteristics were evaluated.

In order to obtain white light having the same light color (correlated color temperature of about 3800 K, duv, chromaticity), the phosphor layer 3 has a thickness of about 500 μm in Example 1 and about 100 μm in Comparative Example 1. did. The light emission characteristics of the SrAlSiN ₃ : Eu ²⁺ red phosphor of Example 1 and the Sr ₂ Si ₅ N ₈ : Eu ²⁺ red phosphor of Comparative Example 1 are originally similar. Therefore, for the purpose of further improving the comparison accuracy, the phosphor of Example 1 was selected as a green phosphor having a light emission performance as similar as that of Comparative Example 1. Example 1 _{(Ba, Sr) 2 SiO 4} : Eu 2+ green phosphor, as shown in FIG. _{15 (Ba, Sr) 2 SiO} 4: Eu 2+ as the green phosphor, the atomic ratio of Sr and Ba Are different, but the dependence of the internal quantum efficiency and the external quantum efficiency on the excitation wavelength is similar.

  Hereinafter, the light emission characteristics of the light emitting devices according to Example 1 and Comparative Example 1 will be described.

  26 and 27 show the emission spectra of Example 1 and Comparative Example 1, respectively. As can be seen from FIGS. 26 and 27, the light emitting devices of Example 1 and Comparative Example 1 have similar emission spectra, and both have white light having emission peaks near 470 nm and 600 nm, that is, blue light. White light is emitted by mixing yellow and yellow light.

  Table 1 shows the light emission characteristics of the light emitting devices of Example 1 and Comparative Example 1.

  The duv in Table 1 is an index indicating the deviation from the black body radiation locus of white light. Ra is an average color rendering index, and R9 is a red special color rendering index, which represents how faithfully the test light reproduces the test color when the color viewed with the reference light is 100.

Under conditions of approximately equal light colors (correlated color temperature, duv and chromaticity), Example 1 has a low emission intensity under light irradiation of 470 nm (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ green phosphor In spite of the above, Ra, R9 and luminous flux almost equal to those of Comparative Example 1 were shown. That is, it was found that Example 1 has the same luminous performance as Comparative Example 1, which is a conventional light emitting device that achieves both high color rendering properties and high luminous flux. The reason for this is that the internal quantum efficiency of the phosphor used in Example 1 under the light irradiation emitted by the blue LED is high, the light emitted by the blue LED absorbed by the phosphor is efficiently wavelength-converted and emitted, It is considered that the light emitted from the blue LED that was not absorbed was output efficiently.

  The correlated color temperature of the light emitting device can be arbitrarily adjusted by changing the phosphor concentration and the thickness of the phosphor layer, and has at least one phosphor having a predetermined spectral distribution and a predetermined internal quantum efficiency; A phosphor layer is configured using a base material such as a resin having a transmittance of 100%, for example, and a light emitting device is configured using a light emitting element having a predetermined spectral distribution and a constant output, and a correlated color of output light Luminescent characteristics such as the color rendering index and the luminous flux when the temperature is changed can be evaluated by simulation. However, if only the color rendering evaluation number is used, the numerical value of the internal quantum efficiency may not be present, and simulation evaluation can be performed only by the spectral distribution of the phosphor and the light emitting element. Therefore, in order to investigate the light color that achieves both high color rendering properties and high luminous flux of the light emitting device, Ra of the white light emitted by the light emitting devices of Example 1 and Comparative Example 1 when the correlated color temperature is changed by setting duv to 0 is used. And the behavior of the relative luminous flux were evaluated by simulation.

  FIG. 28 shows the result of evaluating the relative luminous flux of white light emitted from the light emitting devices of Example 1 and Comparative Example 1 when the correlated color temperature is changed by simulation. From FIG. 28, Example 1 and Comparative Example 1 show the same behavior, and when a light emitting device having a correlated color temperature of white light of 3000 K to 6000 K, preferably 3500 K to 5000 K, is manufactured, Example 1 is compared. It can be seen that Example 1 shows a relatively high luminous flux corresponding to 95 to 100% of the luminous flux when the correlated color temperature is 3797K. The luminous flux when the correlated color temperature of Comparative Example 1 is 3797K is indicated by a solid line in FIG.

  FIG. 29 shows the result of evaluating the relative luminous flux of white light emitted from the light emitting devices of Example 1 and Comparative Example 1 when the correlated color temperature is changed by simulation. Example 1 and Comparative Example 1 show that when a light emitting device having a correlated color temperature of white light of 2000K to 5000K, preferably 2500K to 4000K is manufactured, Ra has a relatively high numerical value of 80 or more. .

  28 and 29, Example 1 and Comparative Example 1 are for the case where a light emitting device having a correlated color temperature of white light of 3000K to 5000K, preferably 3000K to 4500K, more preferably 3500K to 4000K. It can be seen that a light emitting device having both a high luminous flux and a high Ra can be obtained.

(Example 2)
The (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ green phosphor of Example 1 was changed from a phosphor having an emission peak near a wavelength of 555 nm to a phosphor having an emission peak near a wavelength of 535 nm. As a second example, a light emitting device in which the correlated color temperature was changed was configured.

  In FIG. 30, the result of having evaluated Ra of the white light which Example 2 emits by simulation was shown. From FIG. 30, when a light emitting device having a lower correlated color temperature shows higher Ra, and a light emitting device emitting white light with a correlated color temperature of 2000 K or more and 5000 K or less is produced, Ra shows 80 or more, and the relative color temperature In the case of 3000K or less, it can be seen that Ra indicates 90 or more.

  In FIG. 31, the result of having evaluated R9 of the white light which Example 2 emits by simulation was shown. From FIG. 31, when a light emitting device that emits white light having a correlated color temperature of 2000 K or more and 8000 K or less is produced, R9 shows a high value of 40 or more, and when it is 2500 K or more and 6500 K or less, about 60 or more and 3000 K or more. It can be seen that a high R9 of about 80 or more is exhibited when the temperature is 5000K or less.

  FIG. 32 shows the result of evaluating the relative luminous flux of white light emitted from the light emitting device of Example 2 when the correlated color temperature is changed by simulation. From FIG. 32, when a light emitting device having a correlated color temperature of white light of 2500 K to 8000 K, preferably 3000 K to 5000 K, more preferably 3500 K to 4500 K is manufactured in Example 2, Example 2 is a comparative example. 1 shows a relatively high luminous flux corresponding to 82 to 85% of the luminous flux when the correlated color temperature is 3797K. The luminous flux when the correlated color temperature of Comparative Example 1 is 3797K is shown by a solid line in FIG.

  30 to 32, the light-emitting device of Example 2 emits white light having a correlated color temperature of 3000 K or more and 5000 K or less. Ra and R9 are 80 or more and color rendering is compatible with high luminous flux. High output light is emitted. Further, when the correlated color temperature is 3500K or more and 4500K or less, Ra and R9 are 82 or more, and a more preferable color rendering output light compatible with a high luminous flux is emitted, and in particular, the relative color temperature is about 4000K. In some cases, Ra and R9 are 85 or more, and an output light having a more preferable color rendering property that achieves a higher luminous flux is emitted.

FIG. 33 shows emission spectrum simulation data of the light emitting device of Example 2 that emits warm white light having a particularly preferable correlated color temperature of 4000 K (duv = 0). In the case of this emission spectrum, the chromaticity (x, y) is (0.3805, 0.3768), Ra is 86, and R9 is 95. The shape of this emission spectrum is the emission peak in the wavelength region of 460 to 480 nm by the blue LED and the emission in the wavelength region of 520 to 550 nm by the green phosphor of Example 2 that emits light based on the 5d-4f electronic transition of the rare earth ions. Intensity ratio between the peak and the emission peak in the wavelength region of 610 to 640 nm by the red phosphor of Example 2 emitting light based on the 5d-4f electronic transition of rare earth ions, 460 to 480 nm: 520 to 550 nm: 610 to 640 nm Is 24-28: 12-15: 16-20. One of the preferred embodiments of the present invention is a light emitting device that emits warm white light whose emission peak has the shape of the emission spectrum of the above ratio. Note that the phosphor emitting light based on the 5d-4f electronic transition of the rare earth ion described above refers to a phosphor mainly containing Eu ²⁺ or Ce ³⁺ rare earth ions as emission center ions. Such phosphors have similar emission spectrum shapes regardless of the type of phosphor matrix when the wavelengths of the emission peaks are the same.

Further, the green phosphor of Example 1 was changed to a (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ green phosphor having an emission peak in the wavelength range of 520 to 550 nm, and the emission peak in the wavelength range of 560 to 580 nm. It was found that when a (Sr, Ba) ₂ SiO ₄ : Eu ²⁺ yellow phosphor having the above is further added, a light emitting device having high color rendering properties can be obtained by simulation. For example, in output light having a relative color temperature of 3800 K, duv = 0, and chromaticity (0.3897, 0.3823), Ra was 88, R9 was 72, and relative luminous flux was 93%.

When the green phosphor of Example 1 is changed to a shorter (for example, (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ green phosphor) having an emission peak in the wavelength region of 520 nm, the light color condition for duv = 0 The relationship between correlated color temperature, Ra, R9, and relative luminous flux was evaluated by simulation. As a result, it was found that as the light emitting device having a shorter emission peak wavelength of the green phosphor, the numerical values of Ra, R9 and relative luminous flux are lower, and the performance as the lighting device is lowered. For example, when a green phosphor having a light emission peak at a wavelength of 520 nm is used, at correlated color temperature 3800K, duv = 0, and chromaticity (0.3897, 0.3823), Ra is 80, R9 is 71, and relative luminous flux is It was 85%. From the above, it is preferable to use a green phosphor having an emission peak wavelength of 525 nm or more.

In addition, although Example 1 and Example 2 used SrAlSiN ₃ : Eu ²⁺ red phosphor, it is a red phosphor represented by a composition formula (M _1-x Eu _x ) AlSiN ₃ , where M is It is at least one element selected from Mg, Ca, Sr, Ba and Zn, and x is not particularly limited as long as x is a numerical value satisfying the formula 0.005 ≦ x ≦ 0.3. For example, CaAlSiN ₃ : Eu ²⁺ red phosphor has the same effect.

Further, instead of SrAlSiN ₃ : Eu ²⁺ red phosphor, for example, a known nitride phosphor or oxynitride phosphor exhibiting similar emission characteristics, for example, a composition formula (M _1-x Eu _x ) SiN ₂ or a nitridosilicate phosphor represented by a composition formula (M _1-x Eu _x ) ₂ Si ₅ N ₈ or an oxontri represented by a composition formula (M _1-x Eu _x ) ₂ Si ₄ AlON ₇ Even when a doluminosilicate phosphor or the like is used, the same effect is recognized. However, M in the composition formula is at least one element selected from Mg, Ca, Sr, Ba and Zn, and x is a numerical value satisfying the formula 0.005 ≦ x ≦ 0.3.

Further, the green phosphor and the yellow phosphor are not limited to those used in the above-described embodiments, and any phosphor that emits light having an emission peak in a wavelength region of 525 nm or more and less than 600 nm, for example, a wavelength of less than 420 nm. A phosphor having an excitation peak on the longest wavelength side of the excitation spectrum in the region can also be used. It should be noted that YAG: Ce-based phosphors known as phosphors used in white LEDs, such as (Y ₃ (Al, Ga) ₅ O ₁₂ : Ce ³⁺ green phosphor, Y ₃ Al ₅ O ₁₂ : Ce ³⁺ Green phosphor, (Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ yellow phosphor, Y ₃ Al ₅ O ₁₂ : Ce ³⁺ , Pr ³⁺ yellow phosphor, etc. However, the same effect is recognized.

(Example 3)
In this example, instead of the blue LED chip 26 described in Example 1 or 2, a purple LED chip that emits light having a light emission peak in the vicinity of 405 nm with GaInN as a light emitting layer is conductively mounted, and FIGS. The card type illumination module light source shown in FIG. The output light of this embodiment is at least a mixed color light mainly composed of the light emitted from the phosphor contained in the phosphor layer 3 that is excited and emitted by the light emitted from the purple LED chip. Furthermore, as the output light, arbitrary white light was obtained by appropriately selecting the type and amount of the phosphor.

  Hereinafter, the phosphor layer 3 of this example will be described in detail.

The phosphor layer 3 was formed by drying an epoxy resin added with a phosphor. In this example, as a phosphor, a SrAlSiN ₃ : Eu ²⁺ red phosphor having an emission peak in the vicinity of a wavelength of 625 nm (central particle size: 2.2 μm, maximum internal quantum efficiency: 60%, internal quantum under excitation at 405 nm) (Ba: Sr) ₂ SiO ₄ : Eu ²⁺ green phosphor (central particle size: 15.2 μm, maximum internal quantum efficiency: 97%, excitation at 405 nm) Lower internal quantum efficiency: about 97%) and a BaMgAl ₁₀ O ₁₇ : Eu ²⁺ blue phosphor having a light emission peak in the vicinity of a wavelength of 450 nm (central particle size: 8.5 μm, maximum internal quantum efficiency: about 100%, Three types of internal quantum efficiencies under excitation at 405 nm: about 100%) are used. Epoxy resins include epoxy resin (main material) mainly composed of bisphenol A type liquid epoxy resin, and alicyclic acid. Anhydride using two liquids mixture type epoxy resin of epoxy resin (curing material) mainly composed of. The SrAlSiN ₃ : Eu ²⁺ red phosphor has low internal quantum efficiency because the production conditions have not been optimized yet, but the internal quantum efficiency of 1.5 times or more will be improved by optimization of the production conditions in the future. Can be improved. SrAlSiN ₃ : Eu ²⁺ red phosphor and (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ green phosphor and BaMgAl ₁₀ O ₁₇ : Eu ²⁺ blue phosphor are mixed in a weight ratio of about 6:11:30. The mixed phosphor and the epoxy resin were mixed at a weight ratio of about 1: 3 (phosphor concentration = 25% by weight).

(Comparative Example 2)
La ₂ O ₂ S: Eu ³⁺ red phosphor having an emission peak in the vicinity of a wavelength of 626 nm in the phosphor (central particle size: 9.3 μm, maximum internal quantum efficiency: 84%, internal quantum efficiency under 405 nm excitation: about (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ green phosphor (center particle size: 15.2 μm, maximum internal quantum efficiency: 97%, under excitation at 405 nm) BaMgAl ₁₀ O ₁₇ : Eu ²⁺ blue phosphor having an emission peak in the vicinity of a wavelength of 450 nm (internal quantum efficiency: about 97%) (central particle size: 8.5 μm, maximum internal quantum efficiency: about 100%, under excitation at 405 nm) A card-type illumination module light source was manufactured in the same manner as in Example 3 using the three types (internal quantum efficiency of about 100%). As the phosphor layer 3, La ₂ O ₂ S: Eu ³⁺ red phosphor, (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ green phosphor and BaMgAl ₁₀ O ₁₇ : Eu ²⁺ blue fluorescence are in a weight ratio. About 155: 20: 33, and the mixture phosphor and epoxy resin were mixed at a weight ratio of about 1: 3 (phosphor concentration = 25 wt%). As in Example 3, output light was obtained by passing a current through the semiconductor light emitting device, and the light emission characteristics were evaluated.

  In order to obtain white light of the same light color (correlated color temperature of about 3800 K, duv, chromaticity), the phosphor layer 3 was formed to have a thickness of about 500 μm in both Example 3 and Comparative Example 2.

  Hereinafter, the light emission characteristics of the light emitting devices according to Example 3 and Comparative Example 2 will be described.

  34 and 35 show the emission spectra of Example 3 and Comparative Example 2, respectively. As can be seen from FIGS. 34 and 35, the light emitting devices of Example 3 and Comparative Example 2 are all white light having emission peaks near 405 nm, 450 nm, 535 nm, and 625 nm, that is, violet light and White light is emitted by the mixture of blue light, green light and red light. Note that the emission peak near 405 nm is light leakage of the violet light emitting element, and the emission peaks near 450 nm, 535 nm, and 625 nm are light obtained by wavelength conversion of the violet light by the phosphor.

  Table 2 shows the light emission characteristics of the light emitting devices of Example 3 and Comparative Example 2.

  The duv in Table 2 is an index indicating the deviation from the black body radiation locus of white light. Ra is an average color rendering index, and R1 to R15 are special color rendering indices, which indicate how faithfully the test light reproduces the test color when the color viewed with the reference light is 100. In particular, R9 is a red special color rendering index.

  Although the production conditions of the phosphor are not optimized and a red phosphor having a low maximum performance such as a maximum internal quantum efficiency of 60% is used, Example 3 has almost the same light color (correlated color temperature, white light having a relative luminous flux 17% higher than that of Comparative Example 2 was emitted under the conditions of duv and chromaticity). The maximum internal quantum efficiency of the red phosphor used in Comparative Example 2 is 83%, and the output efficiency of the light-emitting device may be further improved by about 20%, but in the case of the red phosphor used in Example 3 Then, the maximum internal quantum efficiency is 60%, and the white output of the light-emitting device can be further improved by about 65% or more. That is, theoretically and finally, the material configuration of the light emitting device of Example 3 emits white light with a higher luminous flux.

  In addition, when the light emitting device of Example 3 was configured to emit white light having a correlated color temperature of 3800 K by combining at least the above-described phosphors, the Ra was larger than that of Comparative Example 2. Further, not only R9 but also all the special color rendering indexes of R1 to R15 were larger than those of Comparative Example 2. This indicates that Example 3 emits white light with extremely good color rendering properties.

  In addition, the light-emitting device of Example 3 is a light-emitting device that emits white light with high color rendering properties of R1 to R15, each having a special color rendering index of 80 or more, and indicates that it emits light close to sunlight. ing. Such a light emitting device is particularly suitable for medical use, and provides an LED light source that can be applied to, for example, an endoscope, and is an excellent endoscope that can be diagnosed under light close to sunlight. A system can also be provided.

  Hereinafter, in order to investigate the light color that achieves both high color rendering properties and high luminous flux of the light emitting device, Ra of the white light emitted from the light emitting devices of Example 3 and Comparative Example 2 when the correlated color temperature is changed with duv being 0 And the results of evaluating the behavior of the relative luminous flux by simulation will be described.

  FIG. 36 shows the result of evaluating the relative luminous flux of white light emitted from the light emitting devices of Example 3 and Comparative Example 2 when the correlated color temperature is changed by simulation. From FIG. 36, it can be seen that the light-emitting device of Example 3 emits white light with a luminous flux that is about 10 to 20% higher than that of Comparative Example 2 over a wide correlated color temperature range of 2000K to 12000K. In the light emitting device of Example 3, when the correlated color temperature of the output light is 2500 K or more and 12000 K or less, preferably 3500 K or more and 7000 K or less, when the correlated color temperature is 3792 K in Comparative Example 2, It can be seen that a relatively high luminous flux corresponding to 110 to 115% level or more of the luminous flux is exhibited. Note that the luminous flux when the correlated color temperature of Comparative Example 2 is 3792K is indicated by a solid line in FIG.

  Hereinafter, for each phosphor used in Example 3 and Comparative Example 2, it is assumed that the production conditions are sufficiently optimized and a phosphor having a maximum internal quantum efficiency of 100% is obtained, and this ideal phosphor is used. The results of a simulation evaluation of the luminous flux in the case of In this simulation, the internal quantum efficiency of each phosphor under excitation at 405 nm was estimated and evaluated as shown in Table 3 below from FIGS.

  FIG. 37 shows the result of evaluating, by simulation, the relative luminous flux of white light emitted from the light emitting devices of Example 3 and Comparative Example 2 when the correlated color temperature is changed when an ideal phosphor is used. It was. From FIG. 37, in the light emitting device of Example 3, when an ideal phosphor is used, it is about 45 to 65% higher than Comparative Example 2 over a wide correlated color temperature range of 2000K to 12000K. It can be seen that a white light beam is emitted. Further, when a light emitting device having a correlated color temperature of white light of 2500 K or more and 12000 K or less, preferably 3500 K or more and 6000 K or less is manufactured, it is 150 to 160% or more of the luminous flux when the correlated color temperature is 3792 K in Comparative Example 2. It can be seen that the corresponding relatively high luminous flux is exhibited. Note that the luminous flux when the correlated color temperature of Comparative Example 2 is 3792K is indicated by a solid line in FIG.

That is, by improving the performance of future SrAlSiN ₃ : Eu ²⁺ red phosphors, a light emitting device that emits a light flux that is about 45 to 65% higher than Comparative Example 2 under the same correlated color temperature evaluation can be obtained. Can be predicted.

  FIG. 38 shows the result of evaluating the average color rendering index (Ra) of white light emitted from the light emitting devices of Example 3 and Comparative Example 2 when the correlated color temperature is changed by simulation. The light emitting device of Example 3 shows a high Ra of 90 or more over a wide correlated color temperature range where the correlated color temperature of white light is 2000 K or more and 12000 K or less, preferably 3000 K or more and 12000 K or less. It can be seen that a very high Ra of 95 or more is shown.

  FIG. 39 shows the results of evaluation by simulation of the red special color rendering index (R9) of the white light emitted from the light emitting devices of Example 3 and Comparative Example 2 when the correlated color temperature is changed. The light emitting device of Example 3 having a correlated color temperature of 2500 K or more and 12000 K or less showed a larger value of R9 than that of Comparative Example 2. In addition, it exhibits a high R9 of 30 or more over a wide correlated color temperature range where the correlated color temperature of white light is 2000K or more and 12000K or less, and 70 or more when 3000K or more and 12000K or less, 80 or more when 3500K or more and 12000K, and 5000K or more and 12000K or less. Shows a high R9 of 90 or more, and is a preferable light emitting device that emits white light having a high red color rendering index. The maximum value of R9 (96 to 98) could be obtained in the correlated color temperature range of 6000K to 8000K.

  36 to 38, it can be seen that the light-emitting device of Example 3 emits higher luminous flux and higher Ra white light than Comparative Example 2 over a wide correlated color temperature range of 2000K to 12000K. Further, when a light emitting device having a correlated color temperature of white light of 2500 K or more and 12000 K or less, preferably 3500 K or more and 7000 K or less, more preferably 4000 K or more and 5500 K or less, a light emitting device that achieves both high luminous flux and high Ra can be obtained. I understand that.

  36 to 39, it can be seen that the light emitting device of Example 3 emits a higher luminous flux and a higher R9 white light than Comparative Example 2 over a wide correlated color temperature range of 2500 K to 12000 K. . Further, when a light-emitting device having a correlated color temperature of white light of 3000 K to 12000 K, preferably 3500 K to 12000 K, more preferably 5000 K to 12000 K, particularly preferably 6000 K to 8000 K, a high luminous flux and a high R9. It can be seen that a light emitting device compatible with both can be obtained.

FIG. 40 shows simulation data of the emission spectrum of the light-emitting device of Example 3 that emits warm white light having a particularly preferable correlated color temperature of 4500 K (duv = 0) between the luminous flux and Ra. In this emission spectrum, the chromaticity (x, y) is (0.3608, 0.3635), Ra is 96, R1 is 98, R2 and R6 to R8 are 97, R3, R10 and R11 are 91, R4 and R14 are 94, R5, R13 and R15 are 99, and R9 and R12 are 88. From this, it can be seen that it is possible to provide a light emitting device that emits white light having a good color rendering property with R1 to R15 having a special color rendering index of 85 or more. The shape of this emission spectrum is 440 to 460 nm, 520 to 540 nm by the RGB phosphor of Example 3 that emits light based on the emission peak in the wavelength region of 400 to 410 nm by the purple LED and the 5d-4f electronic transition of the rare earth ions. The ratio of the intensity with the emission peak in the wavelength region of 610 to 640 nm, 400 to 410 nm: 440 to 460 nm: 520 to 540 nm: 610 to 640 nm is 8 to 10:12 to 14:15 to 17:16 to 18. One of the preferred embodiments of the present invention is a light emitting device that emits warm white light whose emission peak has the shape of the emission spectrum of the above ratio. Note that the phosphor emitting light based on the 5d-4f electronic transition of the rare earth ion described above refers to a phosphor mainly containing Eu ²⁺ or Ce ³⁺ rare earth ions as emission center ions. Such phosphors have similar emission spectrum shapes regardless of the type of phosphor matrix when the wavelengths of the emission peaks are the same.

  FIG. 41 shows simulation data of the emission spectrum of the light-emitting device of Example 3 that emits white light with a particularly preferable correlated color temperature of 5500 K (duv = 0) between the luminous flux and Ra. In this emission spectrum, the chromaticity (x, y) is (0.3324, 0.3410), Ra is 96, R1 and R13 are 98, R2 and R8 and R15 are 97, R3 and R12 are 90, R4 is 92, R5 is 99, R6 is 96, R7 is 95, R9 and R14 are 94, and R10 and R11 are 91. That is, according to the present invention, it is possible to provide a light emitting device that emits white light close to sunlight, for example, suitable for medical use, in which all the special color rendering evaluation numbers of R1 to R15 are 90 or more. The shape of the emission spectrum is 440 to 460 nm and 520 to 440 nm of the RGB phosphor of Example 3 that emits light based on the emission peak in the wavelength region of 400 to 410 nm by the purple LED and the 5d-4f electronic transition of rare earth ions. Intensity ratio with emission peak in wavelength range of 540 nm and 610-640 nm, 400-410 nm: 440-460 nm: 520-540 nm: 610-640 nm is 4-6: 9-11: 8-10: 7-9 is there. One of the preferred embodiments of the present invention is a light emitting device which emits white light whose emission peak has the shape of the emission spectrum of the above ratio.

In Example 3, the case where the purple LED and three types of phosphors of red, green and blue (RGB) are combined and the red phosphor is SrAlSiN ₃ : Eu ²⁺ has been described. However, the purple LED and the SrAlSiN ₃ are described above. : Eu ²⁺ or CaAlSiN ₃ : Eu ^{2+ and the} like, and the phosphor represented by the composition formula of (M _1-x Eu _x ) AlSiN ₃ at least in combination. Similar effects and effects are observed even when four types of (RYGB) or three types of red, yellow, and blue (RYB) are used.

In Example 3, the case where the SrAlSiN ₃ : Eu ²⁺ red phosphor was used was described. However, the phosphor is represented by the composition formula (M _1-x Eu _x ) AlSiN ₃ , and M is Mg. , Ca, Sr, Ba and Zn, and x is not particularly limited as long as x is a numerical value satisfying the formula 0.005 ≦ x ≦ 0.3. Further, the green phosphor is not limited to the green phosphor used in the above-described embodiment, and is not particularly limited as long as it is a green phosphor that emits light having an emission peak in a wavelength region of 500 nm or more and less than 560 nm. Instead of the green phosphor, a yellow phosphor that emits light having an emission peak in a wavelength region of 560 nm or more and less than 600 nm may be used. In addition, the said green or yellow fluorescent substance with preferable light emission output is the fluorescent substance activated by Eu <^2+> or Ce < ³⁺ >.

The characteristics of SrAlSiN ₃ : Eu ²⁺ red phosphors are the same as those of conventional red phosphors such as SrSiN ₂ : Eu ²⁺ , Sr ₂ Si ₅ N ₈ : Eu ²⁺ , Sr ₂ Si ₄ AlON ₇ : Eu ^{2. In} Example 2 or Example 3, instead of the SrAlSiN ₃ : Eu ²⁺ red phosphor, the conventional nitride phosphor or acid described above is used. Even when the nitride phosphor is used, the same effect is recognized.

Hereinafter, for reference, among the phosphors described above, SrAlSiN ₃ : Eu ²⁺ , Sr ₂ Si ₅ N ₈ : Eu ²⁺ , SrSiN ₂ : Eu ²⁺ , (Ba, Sr) ₂ SiO ₄ : Eu ^{2 +} (Emission peak: 555 nm), (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ (Emission peak: 535 nm), (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ (Emission peak: 520 nm), (Sr, Ba ) A method for producing ₂ SiO ₄ : Eu ²⁺ (emission peak: 570 nm) will be described. Commercially available Y ₃ Al ₅ O ₁₂ : Ce ³⁺ yellow phosphor, La ₂ O ₂ S: Eu ³⁺ red phosphor and BaMgAl ₁₀ O ₁₇ : Eu ²⁺ blue phosphor were used.

  Tables 4 and 5 show the weights of the raw material compounds used in the production of each phosphor.

  A method for producing the three types of red phosphors shown in Table 4 will be described. First, using a glove box and a mortar, the predetermined compounds shown in Table 4 were mixed in a dry nitrogen atmosphere to obtain a mixed powder. At this time, no reaction accelerator (flux) was used. Next, the mixed powder is charged into an alumina crucible and pre-baked in a nitrogen atmosphere at a temperature of 800 to 1400 ° C. for 2 to 4 hours, followed by a main baking for 2 hours in an atmosphere of 97% nitrogen at 1600 to 1800 ° C. and 3% hydrogen. Thus, a red phosphor was synthesized. The body color of the phosphor powder after the main firing was orange. After the main firing, predetermined post-treatments such as crushing, classification, washing and drying were performed to obtain a red phosphor.

Next, a method for manufacturing the four types of green phosphor and yellow phosphor shown in Table 5 will be described. First, the predetermined compound shown in Table 5 was mixed in air | atmosphere using the mortar, and mixed powder was obtained. Next, the mixed powder was charged into an alumina crucible and pre-baked in the atmosphere at a temperature of 950 to 1000 ° C. for 2 to 4 hours to obtain a pre-fired powder. To this calcined powder, 3.620 g of calcium chloride (CaCl ₂ ) powder was added and mixed as a flux, followed by main firing for 4 hours in an atmosphere of 97% nitrogen and 3% hydrogen at a temperature of 1200 to 1300 ° C. And yellow phosphor were synthesized. The body color of the phosphor powder after the main firing was green to yellow. After the main firing, predetermined post-treatments such as crushing, classification, washing and drying were performed to obtain a green phosphor and a yellow phosphor.

  As described above, according to the present invention, it is possible to provide a light-emitting device that emits white light and has both high color rendering properties and high luminous flux. In particular, it is possible to provide a light emitting device such as an LED light source that emits warm white light emission and has a strong red light emitting component, and its industrial value is great.

DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Phosphor 3 Phosphor layer 4 Submount element 5 Lead frame 6 Cup 7 Sealing material 8 Case 9 Semiconductor light emitting element 10 Output light 11 Light emission part 12 Illumination module 13 Switch 14 Screw-type base 15 Reflector 16 Fluorescence Internal quantum efficiency of body 17 External quantum efficiency of phosphor 18 Excitation spectrum of phosphor 19 Emission spectrum of phosphor 21 Semiconductor light emitting element 22 Si diode element 23 n electrode 24 p electrode 25 microbump 26 blue LED chip 27 aluminum metal substrate 28 1st insulator thick film 29 Copper electrode 30 2nd insulator thick film 31a, 31b Electrode pad 32 Heat radiation multilayer substrate 33 Back electrode 34 Au wire 35 Bonding pad part 36 Aluminum metal reflecting plate 37 Lens

Claims (10)

A light emitting device and a phosphor layer;
The light-emitting element is a blue light-emitting element that emits light having an emission peak in a wavelength region of 440 nm or more and less than 500 nm,
The phosphor layer has an emission peak in a wavelength region of 500 nm or more and less than 560 nm, a green phosphor containing Eu ²⁺ or Ce ³⁺ as an emission center ion, and an emission peak in a wavelength region of 600 nm or more and less than 660 nm. A red phosphor of nitride or oxynitride containing Eu ²⁺ as a luminescent center ion,
The green phosphor and the red phosphor are excited by the light emitted by the blue light emitting element to emit light,
A light-emitting device including, as output light, a light-emitting component emitted by the green phosphor, the red phosphor, and the blue light-emitting element,
The phosphor layer is substantially free of phosphors other than phosphors activated with Eu ²⁺ or Ce ³⁺ ,
The green phosphor has an excitation peak on a shorter wavelength side than an excitation wavelength that is a peak of light emitted by the blue light emitting element,
In the green phosphor, the excitation peak on the longest wavelength side of the excitation spectrum is not in the wavelength region of the emission peak of the blue light emitting element,
The green phosphor, the nitride is activated by Eu ²⁺ phosphor or oxynitride phosphor, activated with aluminate phosphor with Eu ^2+, nitride phosphor which is activated with Ce ³⁺ Body or oxynitride phosphor, and at least one green phosphor selected from the group consisting of phosphors having a garnet structure activated by Ce ³⁺ ,
The light emitting device according to claim 1, wherein the red phosphor is a nitride aluminosilicate red phosphor. The red phosphor is a phosphor represented by a composition formula (M _1-x Eu _x ) AlSiN ₃ , and M is at least one element selected from Mg, Ca, Sr, Ba and Zn, The light emitting device according to claim 1, wherein x is a numerical value satisfying the expression 0.005 ≦ x ≦ 0.3. The red phosphor is a phosphor represented by a composition formula (M _1-x Eu _x ) ₂ Si ₄ AlON ₇ , and M is at least one element selected from Mg, Ca, Sr, Ba and Zn The light emitting device according to claim 1, wherein x is a numerical value satisfying a formula 0.005 ≦ x ≦ 0.3.   The light emitting device according to claim 1, wherein the green phosphor has an internal quantum efficiency of 80% or more under an excitation wavelength that is a peak of light emitted from the blue light emitting element.   The light emitting device according to any one of claims 1 to 4, wherein the phosphor layer further includes a yellow phosphor having an emission peak in a wavelength region of 560 nm or more and less than 600 nm.   The light emitting device according to claim 1, wherein the phosphor layer substantially does not contain a nitride phosphor or an oxynitride phosphor as a phosphor other than the red phosphor. The green phosphors are Sr _1.5 Al ₃ Si ₉ N ₁₆ : Eu ²⁺ , Ca _1.5 Al ₃ Si ₉ N ₁₆ : Eu ²⁺ , CaSiAl ₂ O ₃ N ₂ : Eu ²⁺ , SrSiAl ₂ O ₃ N ₂ : Eu ²⁺ , CaSi ₂ O ₂ N ₂ : Eu ²⁺ , SrSi ₂ O ₂ N ₂ : Eu ²⁺ , BaSi ₂ O ₂ N ₂ : Eu ²⁺ , SrAl ₂ O ₄ : Eu ²⁺ , Sr ₂ Si ₅ N ₈ : Ce ³⁺ , Ca _1.5 Al ₃ Si ₉ N ₁₆ : Ce ³⁺ , Ca ₂ Si ₅ N ₈ : Ce ³⁺ , Y ₃ (Al, Ga) ₅ O ₁₂ : Ce ³⁺ , BaY ₂ SiAl 7. The light emitting device according to claim 1, wherein the light emitting device is any one selected from the group consisting of ₄ O ₁₂ : Ce ³⁺ and Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce ³⁺ . Emission peak wavelength of the blue light emitting element, the light emitting device according to any one of claims 1 to 7 at 450nm than 480nm or less. The light emitting device according to any one of claims 1 to 8 , wherein an emission peak wavelength of the green phosphor is not less than 510 nm and not more than 550 nm. The light emitting device according to any one of claims 1 to 8 , wherein an emission peak wavelength of the green phosphor is not less than 525 nm and less than 560 nm.

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