JP2012099717A - Semiconductor white light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for improving the color rendering properties of a semiconductor light-emitting device which emits daytime white light or daytime light that belong to a category of high color temperature as the white light for illumination.SOLUTION: The semiconductor white light-emitting device emits white light having a correlation color temperature in the range of 5000-7000K. The emission spectrum has a minimum wavelength in the wavelength range of 460-520 nm, and the intensity of emission spectrum standardized by luminous flux at the minimum wavelength is 80-100% of the intensity at the minimum wavelength of the spectrum of reference light for evaluating the color rendering properties standardized by luminous flux. The intensity at the wavelength of 580 nm of an emission spectrum standardized by luminous flux is 90-100% of the intensity at the wavelength of 580 nm of the spectrum of reference light for evaluating the color rendering properties standardized by luminous flux.

Description

  The present invention relates to a phosphor-converted semiconductor white light-emitting device that generates white light by wavelength-converting light emitted from a semiconductor light-emitting element with a phosphor, and more particularly to a semiconductor white light-emitting device suitable for illumination applications.

A phosphor-converted semiconductor white light-emitting device that generates white light by converting the wavelength of near-ultraviolet to blue light emitted from a semiconductor light-emitting element such as a light-emitting diode or a laser diode with a phosphor is used as a light source for illumination. Attention has been paid. In the background, CaAlSiN ₃ : Eu disclosed in Japanese Patent Application Laid-Open No. 2006-008721 (Patent Document 1) and Sr _x Ca disclosed in Japanese Patent Application Laid-Open No. 2008-7751 (Patent Document 2). _1-x AlSiN ₃ : Eu, Ca _1-x Al _1-x Si _{1 + x} N _3-x O _x : Eu, as disclosed in Japanese Patent Application Laid-Open No. 2007-231245 (Patent Document 3), near ultraviolet to blue A high-intensity red phosphor based on alkaline earth siliconitride has been developed that converts the light into red light with high efficiency.

  As a green phosphor suitable for a semiconductor white light emitting device, an Eu-activated alkaline earth silicate phosphor disclosed in International Publication WO 2007-091687 (Patent Document 4), JP 2005-255895 (Patent) An Eu-activated β sialon phosphor disclosed in Document 5), an Eu-activated alkaline earth silicate nitride phosphor disclosed in International Publication WO 2007-088966 (Patent Document 6), and the like are known.

As a blue phosphor suitable for a semiconductor white light emitting device, Sr ₅ (PO ₄ ) ₃ Cl: Eu disclosed in Japanese Patent Application Laid-Open No. 2004-253747 (Patent Document 7), Japanese Patent Application Laid-Open No. 2004-266201 (Patent Document). BaMgAl ₁₀ O ₁₇ : Eu and the like disclosed in 8) are known.
In 1986, the CIE (International Commission on Illumination) published guidelines for color rendering properties that fluorescent lamps should have, and according to these guidelines, the preferred average color rendering index (Ra) according to the location used is: 60 to less than 80 in factories that perform general work, 80 to less than 90 in factories, hotels, restaurants, stores, offices, schools, hospitals, factories that perform precision work, and 90 or more in places where clinical tests are performed, museums, etc. ing.

JP 2006-008721 A JP 2008-7751 A JP 2007-231245 A International Publication WO2007-091687 JP 2005-255895 A International Publication No. WO2007-088966 JP 2004-253747 A Japanese Patent Application Laid-Open No. 2004-266201

Along with the expansion of the use of semiconductor lighting, further improvements to the color rendering properties of the semiconductor white light emitting device used for the light source are required. These include not only the average color rendering index Ra, but also improvements in R9, R10, R11 and R12 (respectively indicators of reproducibility of highly saturated red, yellow, green and blue).
Therefore, the present invention provides a color rendering property for a semiconductor light emitting device that emits daylight white light (color temperature around 5000K) and daylight color light (color temperature around 6500K) belonging to a class having a high color temperature as white light for illumination. The main purpose is to provide improved technology.

According to the present invention, the following semiconductor white light emitting device is provided.
(1) A semiconductor light emitting device and a wavelength conversion unit that absorbs light emitted from the semiconductor light emitting device and emits light having a wavelength different from that of the light emitted from the semiconductor light emitting device, and applies a current to the semiconductor light emitting device. Thus, a semiconductor white light emitting device that emits white light having a correlated color temperature in the range of 5000 to 7000 K including light emitted from the wavelength conversion unit, and the emission spectrum has a minimum wavelength in the wavelength range of 460 to 520 nm. The intensity at the minimum wavelength of the emission spectrum normalized with the luminous flux is 80 to 100% of the intensity at the minimum wavelength of the spectrum of the color rendering standard reference light normalized with the luminous flux, and the emission normalized with the luminous flux. The intensity at a wavelength of 580 nm of the spectrum is 90 to 100% of the intensity at a wavelength of 580 nm of the spectrum of the reference light for color rendering properties normalized by the luminous flux. The semiconductor white light emitting device, characterized in that.
(2) The semiconductor white light emitting device according to (1), wherein the wavelength conversion unit includes a blue phosphor, a green phosphor, and a red phosphor that are excited by the semiconductor light emitting element to emit light.
(3) The blue phosphor includes an Eu-activated alkaline earth halophosphate phosphor having an emission spectrum peak wavelength in the range of 450 to 460 nm and a half-wavelength on the long wavelength side of 490 nm or more ( The semiconductor white light-emitting device as described in 2).
(4) The semiconductor white light emitting device according to (3), wherein the green phosphor includes at least one of an alkaline earth silicate nitride phosphor and a sialon phosphor.
(5) The semiconductor white light emitting device according to (3), wherein the green phosphor includes a phosphor having an emission spectrum peak wavelength in a range of 535 to 550 nm and a full width at half maximum of 50 to 70 nm.
(6) The above (5), wherein the phosphor having a peak wavelength of the emission spectrum in the range of 535 to 550 nm and the full width at half maximum of 50 to 70 nm includes an alkaline earth silicate nitride phosphor or a sialon phosphor. The semiconductor white light emitting device described in 1.
(7) The semiconductor white light emitting device according to (6), wherein the phosphor having a peak wavelength of the emission spectrum in the range of 535 to 550 nm and the full width at half maximum of 50 to 70 nm includes a β sialon phosphor.
(8) The semiconductor white light emitting device according to (7), wherein the red phosphor includes a phosphor having a peak wavelength of an emission spectrum of 620 nm or less.
(9) The semiconductor white light emitting device according to (8), wherein the phosphor having a peak wavelength of the emission spectrum of 620 nm or less includes an Eu-activated alkaline earth siliconitride phosphor containing Sr and Ca.
(10) The semiconductor white light emission according to any one of (1) to (9), wherein the correlated color temperature of the white light is 6000 K or more and the maximum wavelength of the emission spectrum on the longest wavelength side is 610 nm or less. apparatus.
(11) A semiconductor light emitting device and a wavelength conversion unit that absorbs light emitted from the semiconductor light emitting device and emits light having a wavelength different from that of the light emitted from the semiconductor light emitting device, and applies a current to the semiconductor light emitting device. Accordingly, a semiconductor white light-emitting device that emits white light having a correlated color temperature in the range of 5000 to 7000 K including light emitted from the wavelength conversion unit, the average color rendering index Ra is 95 or more, and special color rendering evaluation Number of R9, R10, R11, and R12 is 85 or more, The semiconductor white light-emitting device characterized by the above-mentioned.
(12) The white semiconductor light-emitting device according to (11), wherein the correlated color temperature of the white light is within a range of 5000 to 6000 K, and all of the color rendering indexes R1 to R14 are 90 or more.
(13) The semiconductor white light emitting device according to (11), wherein the correlated color temperature of the white light is 6000 or more and all of the color rendering indexes R1 to R14 are 85 or more.
(14) The semiconductor white light emission according to any one of (11) to (13), wherein the wavelength conversion unit includes a blue phosphor, a green phosphor, and a red phosphor that are excited by the semiconductor light emitting element to emit light. apparatus.
(15) The blue phosphor includes an Eu-activated alkaline earth halophosphate phosphor having an emission spectrum peak wavelength in the range of 450 to 460 nm and a half-wavelength on the long wavelength side of 490 nm or more ( 14) The semiconductor white light emitting device according to 14).
(16) The semiconductor white light emitting device according to (15), wherein the green phosphor includes a phosphor having an emission spectrum peak wavelength in a range of 535 to 550 nm and a full width at half maximum of 50 to 70 nm.
(17) The green phosphor includes an alkaline earth silicate nitride phosphor having an emission spectrum peak wavelength in the range of 535 to 550 nm and a full width at half maximum of 50 to 70 nm. Semiconductor white light emitting device.
(18) The semiconductor white light-emitting device according to (16), wherein the green phosphor includes a sialon phosphor having an emission spectrum peak wavelength in the range of 535 to 550 nm and a full width at half maximum of 50 to 70 nm.
(19) The semiconductor white light-emitting device according to (18), wherein the green phosphor includes a β sialon phosphor.
(20) A semiconductor light emitting device, and a wavelength converter that absorbs light emitted from the semiconductor light emitting device and emits light having a wavelength different from that of the light emitted from the semiconductor light emitting device. A blue phosphor, a green phosphor, and a red phosphor that are excited by the device to emit light, and when a current is applied to the semiconductor light emitting device, a correlated color temperature including light emitted by the wavelength conversion unit is 6000 to 7000 K White light in the range is emitted, the average color rendering index Ra is 95 or more, the special color rendering index R9, R10, R11 and R12 is 85 or more, and the maximum wavelength of the emission spectrum on the longest wavelength side is 610 nm or less A semiconductor white light emitting device.
(21) The blue phosphor includes an Eu-activated alkaline earth halophosphate phosphor in which a peak wavelength of an emission spectrum is in a range of 450 to 460 nm and a half-value wavelength on the long wavelength side is 490 nm or more ( 20) The semiconductor white light emitting device according to 20).
(22) The semiconductor white light emitting device according to (20) or (21), wherein the green phosphor contains β sialon: Eu.
(23) The semiconductor white light emitting device according to any one of (20) to (22), wherein the red phosphor includes an Eu-activated alkaline earth silicon nitride phosphor containing Sr and Ca.

  Since the semiconductor white light emitting device according to the embodiment of the present invention is excellent in color rendering, it can be preferably used as a light source for illumination.

FIG. 1 shows a cross-sectional structure of a semiconductor white light emitting device according to an embodiment of the present invention. FIG. 2 shows a cross-sectional structure of a semiconductor white light emitting device according to an embodiment of the present invention. FIG. 3 shows a cross-sectional structure of a semiconductor white light emitting device according to an embodiment of the present invention. FIG. 4 shows an emission spectrum of the semiconductor white light emitting device according to the embodiment of the present invention. FIG. 5 shows an emission spectrum of the semiconductor white light emitting device according to the embodiment of the present invention. FIG. 6 shows an emission spectrum of the semiconductor white light emitting device according to the embodiment of the present invention. FIG. 7 shows an emission spectrum of the semiconductor white light emitting device according to the embodiment of the present invention. FIG. 8 shows an xy chromaticity diagram (CIE 1931).

Hereinafter, the present invention will be described with reference to embodiments and examples, but the present invention is not limited to the following embodiments and examples, and may be arbitrarily modified without departing from the scope of the invention. can do.
In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

In the composition formulas of the phosphors described in the present specification, each composition formula is delimited by a punctuation mark (,). In addition, when a plurality of elements are listed separated by commas (,), one or two or more of the listed elements may be included in any combination and composition. For example, the composition formula “(Ba, Sr, Ca) Al ₂ O ₄ : Eu” is expressed by “BaAl ₂ O ₄ : Eu”, “SrAl ₂ O ₄ : Eu”, “CaAl ₂ O ₄ : Eu”, “ _{Ba 1-p Sr p Al 2} O 4: Eu "," _{Ba 1-p Ca p Al 2} O 4: Eu "," _{Sr 1-p Ca p Al 2} O 4: Eu "and" _{Ba 1-p- q} Sr _p Ca _q Al ₂ O ₄ : Eu ”is comprehensively shown (in the above formula, 0 <p <1, 0 <q <1, 0 <p + q <1). ).

  FIG. 1 is a sectional view of a semiconductor white light emitting device having an SMD type LED structure embodying the present invention. The semiconductor white light emitting device 10 includes a semiconductor light emitting element 12 fixed on a bottom surface of a cup provided in a package 11. And a wavelength converter 13 provided in the cup and surrounding the semiconductor light emitting element 12. The wavelength conversion unit 13 contains a phosphor (not shown) that is excited by the semiconductor light emitting element 12 and emits light. The semiconductor light emitting element 12 is connected to a wiring pattern (not shown) formed on the bottom surface of the package 11, and current can be supplied to the semiconductor light emitting element 12 from a power source placed outside the package 11. It has become.

  When a forward current is applied to the semiconductor light emitting device 12, the semiconductor light emitting device 12 emits light, and at least a part of this light is absorbed and the phosphor included in the wavelength conversion unit 13 emits light. The wavelength conversion unit 13 includes a blue phosphor, a green phosphor, and a red phosphor, and the wavelength conversion unit 13 in which white light synthesized from the light emitted by each of the three phosphors is exposed on the top of the package 11. Released from the surface. When the light emitted from the semiconductor light emitting element 12 includes a visible component, the visible component may be included in the white light.

  The amount of each phosphor added to the wavelength conversion unit 13 is adjusted so that the correlated color temperature of the white light emitted from the semiconductor white light emitting device 10 is in the range of 5000 to 7000K. The JIS standard defines that the color of the light source can be expressed by the correlated color temperature only when the deviation Duv from the blackbody radiation locus is in the range of -20 to +20. Light with Duv outside this range cannot be used for white illumination. From the viewpoint of comfort when used for illumination, the output light Duv of the semiconductor white light emitting device 10 is preferably in the range of −6.0 to +6.0, more preferably −6.0 to +2.0. In the range of -6.0 to 0.0, particularly preferably in the range of -6.0 to 0.0.

The semiconductor white light emitting device 10 satisfies the following first condition and second condition regarding the emission spectrum at the same time.
First condition: the emission spectrum has a minimum wavelength within the range of 460 to 520 nm, and the intensity at the minimum wavelength of the emission spectrum normalized by the luminous flux is the reference light for color rendering evaluation standardized by the luminous flux. It is 80 to 100% of the intensity at the minimum wavelength of the spectrum.

Second condition: The intensity at a wavelength of 580 nm of the emission spectrum normalized by the light beam is 90 to 1 of the intensity at a wavelength of 580 nm of the spectrum of the reference light for color rendering properties normalized by the light beam.
00%.
Here, the minimum wavelength of the emission spectrum referred to in the first condition is a wavelength at which the intensity of the emission spectrum takes a minimum value. Therefore, the phrase “the emission spectrum has a minimum wavelength in the range of 460 to 520 nm” means that there exists a wavelength in which the intensity of the emission spectrum takes a minimum value in the range of 460 to 520 nm.

  The reference light for color rendering property evaluation referred to in the first condition and the second condition is a reference light defined in Japanese Industrial Standard JIS Z8726: 1990 that defines a color rendering property evaluation method of a light source, and is a semiconductor that is a sample light source. When the correlated color temperature of the white light emitting device 10 is less than 5000K, the light of a complete radiator, and when the correlated color temperature is 5000K or more, it is CIE daylight. The definition of perfect radiator and CIE daylight follows JIS Z8720: 2000 (corresponding international standard ISO / CIE 10526: 1991).

The spectrum normalized by the light beam referred to in the first condition and the second condition is a spectrum normalized so that the light beam Φ determined by the following formula (1) becomes 1 (unity) (the following formula ( 1) Spectral radiant flux Φ _e ).

here,
Φ: luminous flux [lm]
K _m : Maximum visibility [lm / W]
Vλ: Photopic standard relative luminous sensitivity Φ _e : Spectral radiant flux [W / nm]
λ: wavelength [nm].

  The first condition is that the semiconductor white light emitting device 10 has a reproducibility concerning yellow with high saturation (index is the special color rendering index R10) and a reproducibility concerning blue with high saturation (the index is the special color rendering index R12). It is a guideline to make it excellent. The second condition is a guideline for making the semiconductor white light emitting device 10 excellent in reproducibility (index is a special color rendering index R9) relating to red with high saturation. In the semiconductor white light emitting device 10, in order to satisfy the first condition and the second condition at the same time, the blue phosphor, the green phosphor and the red phosphor to be added to the wavelength conversion unit 13 are appropriately selected. is important.

  In the semiconductor white light emitting device 10, the semiconductor light emitting element 12 may be a light emitting diode, a super luminescent diode, a laser diode or the like, but is preferably a light emitting diode. The emission peak wavelength of the semiconductor light emitting device 12 can be in the range of 350 to 430 nm, but is preferably in the range of 400 to 430 nm from the viewpoint of reducing the Stokes shift loss. When the emission peak wavelength of the semiconductor light emitting element 12 is 410 nm or less, the visible component contained in the light emitted from the semiconductor light emitting element 12 is the chromaticity of white light emitted from the semiconductor white light emitting device 10 or the semiconductor white light emitting device 10. The effect on color rendering is small.

Among semiconductor light emitting devices having a light emission peak wavelength in the wavelength region of 400 to 430 nm, an InGaN-based violet light emitting diode can be particularly preferably used. The InGaN-based light-emitting diode is a light-emitting diode having a double hetero pn junction type light-emitting structure in which an MQW active layer including an InGaN well layer is sandwiched between p-type and n-type GaN-based cladding layers, and has an emission peak wavelength of 410 to 430 nm. It is known that the luminous efficiency is maximized when the above range is satisfied. Considering this and the excitation characteristics of the blue phosphor, it is preferable to use an InGaN-based purple light-emitting diode having an emission peak wavelength in the range of 400 to 415 nm as the semiconductor light-emitting element 12. In general, the blue phosphor is strongly excited by ultraviolet to near-ultraviolet light, but on the side where the wavelength of the excitation light becomes longer than 405 nm, it rapidly decreases as the wavelength increases.

The blue phosphor included in the wavelength conversion unit 13 has an emission color of “PURPULISH BLUE”, “BLUE” or “GR” in the xy chromaticity diagram (CIE 1931) shown in FIG.
It is a fluorescent substance classified into “EENISH BLUE”. In order to satisfy the first condition, it is desirable to use a blue phosphor having an emission spectrum peak wavelength in the range of 450 to 470 nm and a full width at half maximum of 50 to 80 nm.

One suitable example of the blue phosphor is Eu-activated alkaline earth aluminate phosphor, among which (Ba, Sr, Ca) MgAl ₁₀ O ₁₇ : Eu, in particular BaMgAl ₁₀ O ₁₇ : Eu called BAM. is there. The emission spectrum of BAM has a peak wavelength near 450 nm, and its full width at half maximum is about 50 nm. Since the full width at half maximum of the emission spectrum of a normal InGaN-based blue light emitting diode is 30 nm or less, the emission spectrum of BAM is considerably broader than this. A white-white or daylight-color semiconductor white light-emitting device using an InGaN-based blue light-emitting diode as a blue light component generation source cannot be said to have good reproducibility for highly saturated blue, and its special color rendering index R12 is 75. Not reach.

Another preferred example of the blue phosphor is (Ca, Sr, Ba) ₅ (PO ₄ ) ₃ (Cl, F, Br):
It is an Eu activated alkaline earth halophosphate phosphor represented by Eu. However, since Sr ₅ (PO ₄ ) ₃ Cl: Eu (commonly referred to as SCA) has a full width at half maximum of an emission spectrum of less than 30 nm,
The first condition cannot be satisfied using only SCA. A preferred Eu-activated alkaline earth halophosphate phosphor is a phosphor having a broader emission spectrum than SCA (hereinafter referred to as “SBCA”) in which a part of Sr of SCA is substituted with at least one of Ba and Ca. Say). For example, SBCA represented by the composition formula Sr _a Ba _b Eu _x (PO ₄ ) ₃ Cl (where a + b = 5-x) has x of 0.5 to 0.6 and b / (a + b) of 0. By setting it to 2 to 0.3, the full width at half maximum of the emission spectrum can be broadened from less than 30 nm of SCA to about 80 nm.

The broadened emission spectrum of SBCA exhibits an asymmetric shape in which the spread on the long wavelength side is extremely larger than the short wavelength side of the peak wavelength. For example, in Sr _a Ba _b Eu _x (PO ₄ ) ₃ Cl (where a + b = 5-x) where x is 0.5 to 0.6 and b / (a + b) is 0.2 to 0.3, when the difference between the half wavelength of the peak wavelength and short wavelength side was [Delta] [lambda] _S, the difference [Delta] [lambda] _L of the half wavelength of the peak wavelength and the long wavelength side, twice or more [Delta] [lambda] _S, even 2.5 times or more in Can also be. Here, the half-value wavelength means a wavelength at which the intensity of the emission spectrum is half of the intensity at the peak wavelength. Such a light emission characteristic of SBCA is extremely advantageous in satisfying the first condition. In consideration of the average color rendering index Ra of the semiconductor white light emitting device 10, the Eu-activated alkaline earth halophosphate phosphor used for the wavelength conversion unit 10 has a peak wavelength of the emission spectrum in the range of 450 to 460 nm, and is long. It is desirable that the half-value wavelength on the wavelength side is 490 nm or more.

The blue phosphor that can be added to the wavelength conversion unit 13 is not limited to one type. For example, both Eu-activated alkaline earth aluminate phosphor and Eu-activated alkaline earth halophosphate phosphor can be added to the wavelength conversion unit 13. In addition, two or more kinds of Eu-activated alkaline earth halophosphate phosphors having different compositions and emission characteristics can be added to the wavelength conversion unit 13. The two or more Eu-activated alkaline earth halophosphate phosphors may contain two or more SBCAs having different compositions and emission characteristics.

The green phosphor included in the wavelength conversion unit 13 is a phosphor whose emission color is classified into “GREEN” or “YELLOWISH GREEN” in the xy chromaticity diagram (CIE 1931) shown in FIG. In order to satisfy the first condition and the second condition at the same time, it is desirable to use a green phosphor whose peak wavelength of the emission spectrum is in the range of 525 to 550 nm and whose full width at half maximum is 50 to 70 nm. . Therefore, a green phosphor using Eu ²⁺ as an activator can be preferably used. Examples of the green phosphor using Eu ²⁺ as an activator include (Ba, Ca, Sr, Mg) ₂ SiO ₄ : Eu, (Ba, Sr, Ca) ₂ (Mg, Zn) S.
i ₂ O ₇ : alkaline earth silicate phosphor such as Eu, (Ba, Ca, Sr) ₃ Si ₆ O ₁₂ N ₂ : Eu, (Ba, Ca, Sr) ₃ Si ₆ O ₉ N ₄ : Eu, (Ca, Sr, Ba) Si ₂ O ₂ N ₂ : alkaline earth silicate nitride phosphor such as Eu, β sialon: Eu, Sr ₃ Si ₁₃ A
There are sialon phosphors such as l ₃ O ₂ N ₂₁ : Eu and Sr ₅ Al ₅ Si ₂₁ O ₂ N ₃₅ : Eu.

The alkaline earth silicate nitride phosphor having the basic composition exemplified above can control the peak wavelength of the emission spectrum in a range including 525 to 540 nm. The emission characteristics (peak wavelength and full width at half maximum of emission spectrum) of an alkaline earth silicate nitride phosphor having an emission peak wavelength in the range of 525 to 530 nm are (Ba, Ca, Sr, Mg) ₂ SiO ₄ : Eu and It is similar.

Some of the green phosphors include Ca ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce, CaSc ₂ O ₄ : C
Some, such as e, use Ce ³⁺ as an activator. However, it is difficult to satisfy the second condition using only this type of green phosphor. This is because the green phosphor using Ce ³⁺ as an activator has a broad emission spectrum, and the emitted light contains excessive components having a wavelength near 580 nm. In addition, many green phosphors using Ce ³⁺ as an activator have an excitation spectrum peak near a wavelength of 450 nm, so when used with a blue phosphor, multi-stage excitation (cascade excitation) occurs and wavelength conversion loss increases. There is a problem to do.

The green phosphor used for the wavelength converter 13 is not limited to one type. For example, the green fluorescence activated alkaline earth silicate nitride body Eu ^2+, both of the green phosphor of sialon, which is activated by Eu ^2+, are added to the wavelength conversion unit 13 Can do. Alternatively, a plurality of sialon-based green phosphors having different matrix compositions can be added to the wavelength conversion unit 13.
The red phosphor included in the wavelength conversion unit 13 is a phosphor whose emission color is classified into “RED”, “REDDISH ORANGE”, or “ORANGE” in the xy chromaticity diagram (CIE1931) illustrated in FIG. 8. A preferred example of the red phosphor is a phosphor having Eu ²⁺ as an activator and a crystal composed of an alkaline earth silicon nitride, for example, (Ca, Sr, Ba) AlSiN ₃ : Eu, (Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu, SrAlSi ₄ N ₇ : Eu, (CaAlSiN ₃ ) _1-x (Si _{(3n + 2) / 4} N _n O) _x : Eu, and the like. The emission spectrum of this type of phosphor is broad, and the full width at half maximum is usually 80 nm or more.

Among the red phosphors represented by (Ca, Sr, Ba) AlSiN ₃ : Eu, those containing Sr and Ca as alkaline earth metal elements emit light having a shorter wavelength than CaAlSiN ₃ : Eu. In addition, (CaAlSiN ₃ ) _1-x (Si _{(3n + 2) / 4} N _n O) _x : Eu is based on a crystal in which Si _{(3n + 2) / 4} N _n O is dissolved in CaAlSiN ₃ as a base. , CaAlSiN ₃ : Eu has a broad emission spectrum, and its peak wavelength is a short wavelength. By controlling the values of n and x, (CaAlSiN ₃ ) _1-x (Si _{(3n + 2) / 4} N _n
The full width at half maximum of the emission spectrum of O) _x : Eu can be 100 nm or more. SrAlSi ₄ N ₇
: Eu has light emission characteristics similar to Ca _1-x Al _1-x Si _{1 + x} N _3−x O _x : Eu. Ca _1−x Al _1−x Si _{1 + x} N _3−x O _x : Eu is (CaAlSiN ₃ ) _1−x (Si _{(3n + 2) / 4} N _n O) _x : In case of n = 2 in Eu It corresponds to.

The second condition can be satisfied by an appropriate combination of the green phosphor and the red phosphor added to the wavelength conversion unit 13. That is, the ratio of the intensity at the wavelength 580 nm of the emission spectrum of the semiconductor white light emitting device 10 normalized by the light beam to the intensity at the wavelength 580 nm of the spectrum of the color rendering property reference light normalized by the light beam is set to 90 to 100%. be able to. By making this ratio as close to 100% as possible, the luminous efficacy of the semiconductor white light emitting device 10 can be increased. This is because the wavelength of 580 nm is included in the wavelength range having the highest visibility. In order to satisfy the second condition preferably, it is useful to use a combination of a plurality of green phosphors having different emission characteristics or a combination of a plurality of red phosphors having different emission characteristics.

As a preferred combination of the blue phosphor, the green phosphor, and the red phosphor added to the wavelength conversion unit 13, the following combination example 1 and combination example 2 can be given.
Combination example 1:
Blue phosphor: Sr _a Ba _b Eu _x (PO ₄ ) ₃ Cl (where a + b = 5-x)
Green phosphor: β sialon: Eu
Red phosphor: Sr _x Ca _1-x AlSiN ₃ : Eu (where 0 <x <1)
Combination example 2:
Blue phosphor ... BAM
Green phosphor (Ba, Ca, Sr) ₃ Si ₆ O ₁₂ N ₂ : Eu
Red phosphor: Ca _1-x Al _1-x Si _{1 + x} N _3-x O _x : Eu
The blue phosphor in the above combination example 1 has a peak in the emission spectrum of 450 to 460 nm and a half-value wavelength on the long wavelength side of 490 nm or more, a in the composition formula Sr _a Ba _b Eu _x (PO ₄ ) ₃ Cl. , B, x are adjusted. In a preferred example, x is about 0.5 and b / (a + b) is adjusted between 0.1 and 0.2. The emission spectrum of β sialon: Eu used as a green phosphor is narrow and usually less than 60 nm, but the first condition is preferably satisfied when used with a broad blue phosphor of the emission spectrum. β sialon: Eu is excellent in durability and heat resistance, and has a high luminous efficacy since it has a narrow emission band in a wavelength range with high visibility.

As the red phosphor in the combination example 1, those having an emission peak wavelength of less than 630 nm, and further less than 620 nm can be preferably used. Since β sialon: Eu used as a green phosphor has a narrow emission spectrum, the second condition can be satisfied even when such a short-wavelength red phosphor is combined. By using a short-wavelength red phosphor for the wavelength conversion unit 13, the luminous efficacy of the semiconductor white light emitting device 10 is improved and the loss due to the Stokes shift is reduced. When the correlated color temperature of the output light of the semiconductor white light emitting device 10 is 6000 to 7000 K, the maximum wavelength that the spectrum of the output light has on the longest wavelength side can be 610 nm or less.

In the above combination example 2, part of the BAM can be replaced with SBCA. Further, a part of (Ba, Ca, Sr) ₃ Si ₆ O ₁₂ N ₂ : Eu can be replaced with a sialon-based green phosphor such as β sialon: Eu.
When attention is paid to the stability of the phosphor added to the wavelength conversion section 13, since the matrix is alkaline earth siliconitride, sialon or alkaline earth silicate nitride, since it contains nitrogen, The bond has a high covalent bond and therefore exhibits excellent durability and heat resistance. In the case of a green phosphor, silicate-based (Ba, Ca, Sr, Mg) ₂ Si
O ₄ : Eu is extremely excellent in luminous efficiency at room temperature, but is not suitable for high power applications because the luminous efficiency is remarkably lowered at high temperatures.

Examples of phosphors not recommended for use include phosphors based on crystals of sulfur-containing compounds. This is because a small amount of sulfur liberated from the base crystal may react with a metal contained in a semiconductor light emitting element, a package, a sealing material, or the like to generate a colored substance. Since the colored substance absorbs visible light, the luminous efficiency of the semiconductor white light emitting device is significantly reduced.
The wavelength conversion unit 13 contains a phosphor other than the blue phosphor, the green phosphor and the red phosphor, for example, a yellow phosphor as long as the satisfaction of the first condition and the second condition is not inhibited. Also good. The yellow phosphor is a phosphor whose emission color is classified into “YELLOW GREEN”, “GREENISH YELLOW”, “YELLOW” or “YELLOWISH ORANGE” in the xy chromaticity diagram (CIE 1931) shown in FIG. . Some yellow phosphors use Ce ³⁺ as an activator and others use Eu ²⁺ as an activator. The former includes a garnet type oxide crystal such as (Y, Gd) ₃ Al ₅ O ₁₂ : Ce, Tb ₃ Al ₅ O ₁₂ : Ce, La ₃ Si ₆ N ₁₁ : Ce, Ca _{1.5 x La 3-x Si 6 N} 11: there is one as a matrix of lanthanum silicon nitride crystals such as Ce. The latter includes a base called alkaline earth silicate called BOSE. Many yellow phosphors using Ce ³⁺ as an activator have an excitation spectrum peak at a wavelength of around 450 nm, so that when used together with a blue phosphor, multistage excitation (cascade excitation) occurs and wavelength conversion loss increases. There is.

  As the matrix material that holds the phosphor in the wavelength conversion unit 13, a resin or glass that is transparent in the emission wavelength range and visible wavelength range of the semiconductor light emitting device 12 can be used. Examples of the resin include various thermoplastic resins, thermosetting resins, photocurable resins, and the like. More specifically, methacrylic resins (polymethyl methacrylate, etc.), styrene resins (polystyrene, styrene-acrylonitrile). Copolymer), polycarbonate resin, polyester resin, phenoxy resin, butyral resin, polyvinyl alcohol, cellulose resin (ethyl cellulose, cellulose acetate, cellulose acetate butyrate, etc.), epoxy resin, phenol resin, silicone resin, etc. . Moreover, as glass, well-known low melting glass, such as a phosphoric acid type, a borophosphoric acid type, a vanadium boric acid type, an alkali silicic acid type, a bismuth type, is illustrated preferably.

  From the viewpoint of heat resistance and light resistance, a silicon-containing compound is preferable as the matrix material of the wavelength conversion unit 13. The silicon-containing compound refers to a compound having a silicon atom in the molecule, for example, an organic material (silicone material) such as polyorganosiloxane, an inorganic material such as silicon oxide, silicon nitride, silicon oxynitride, and borosilicate. And glass materials such as phosphosilicate and alkali silicate. Among these, silicone materials are particularly preferable from the viewpoints of transparency, adhesiveness, ease of handling, and excellent mechanical / thermal stress relaxation characteristics. The silicone-based material usually refers to an organic polymer having a siloxane bond as a main chain. Depending on the curing mechanism, there are types such as a condensation type, an addition type, a sol-gel type, and a photo-curing type.

Fine particles other than the phosphor, for example, a light scattering agent can be dispersed in the wavelength conversion unit 13. The matrix material itself of the wavelength converting unit 13 may be a composite material in which fine particles of submicron size are dispersed in a resin or glass for the purpose of adjusting various properties such as optical characteristics, mechanical characteristics, and heat resistance.
The wavelength conversion unit 13 can contain a phosphor in any manner. For example, the distribution of the phosphor in the wavelength conversion unit 13 may be uniform or non-uniform. Further, a portion containing only a specific phosphor may exist inside the wavelength conversion unit 13. In one example, the wavelength conversion unit 13 can have a multilayer structure in which a layer containing only a blue phosphor, a layer containing only a green phosphor, and a layer containing only a red phosphor are stacked. In this case, a layer not containing a phosphor may be inserted between two layers containing different phosphors. The wavelength conversion unit 13 may have a structure in which a plurality of layers formed of different matrix materials are stacked.

  In the modified embodiment, the wavelength conversion unit 23 can be arranged away from the semiconductor light emitting element 22 as in the semiconductor white light emitting device 20 shown in FIG. The space S separating the semiconductor light emitting element 22 and the wavelength conversion unit 23 may be a cavity, or a part or all of the space S may be filled with a translucent material. The wavelength conversion part 23 may be a thin layer formed on the surface of a transparent support film.

In another modified embodiment, as in the semiconductor white light emitting device 30 illustrated in FIG. 3, the wavelength conversion unit 33 may be a thin layer that covers the surface of the semiconductor light emitting element 32 conformally. The semiconductor white light emitting device 30 further includes a transparent member 34 surrounding the wavelength conversion unit 33. In this example, the upper part of the transparent member 34 is formed in a hemispherical shape.
The semiconductor white light emitting device according to the embodiment of the present invention is not limited to the SMD type LED structure, and may have various structures such as a bullet type LED structure and a chip-on-board structure. In addition, the semiconductor white light emitting device according to the embodiment of the present invention has a lens between the semiconductor light emitting element and the phosphor, or on a path through which the light emitted from the phosphor passes before being emitted to the outside of the light emitting device. , Optical fibers, light guide plates, reflecting mirrors, filters, and other optical elements.

In the semiconductor white light emitting device according to the embodiment of the present invention, in order to satisfy at least one of the first condition and the second condition, the transmittance in a part of the wavelength range of the visible range is the transmittance in the other wavelength range. The shape of the emission spectrum may be controlled by using a filter made to be lower than the above.
A method for producing the blue phosphor Sr _a Ba _b Eu _x (PO ₄ ) ₃ Cl (where a + b = 5-x) will be described as follows.

Among the raw materials of this phosphor, Sr source, Ba source and Eu source include oxides, hydroxides, carbonates, nitrates, sulfates, oxalates, carboxylates of each element of Sr, Ba and Eu. Halides, nitrides and their hydrates can be used.
Further, among the raw materials of this phosphor, PO ₄ sources include Sr, Ba or NH ₄ hydrogen phosphate, phosphate, metaphosphate or pyrophosphate, P ₂ O ₅ , PCl ₃ , PCl ₅ , Sr ₂ PO ₄ Cl, Ba ₂ PO ₄ Cl, phosphoric acid, metaphosphoric acid, pyrophosphoric acid, etc. can be used, and as the Cl source, SrCl, BaCl, NH ₄ Cl, HCl, Sr ₂ PO _{4 Cl,} the Ba 2 _PO 4 Cl, etc., can be used.

In a preferred example, SrHPO ₄ can be used as the Sr source / PO ₄ source, SrCO _{3 as} the Sr source, BaCO _{3 as} the Ba source, and Eu ₂ O ₃ as the Eu source. These raw materials are weighed so that Sr, Ba, Eu, PO ₄ and Cl are contained in a predetermined molar ratio, sufficiently mixed using a ball mill or the like, and then fired. Preferably, SrCl ₂ · 6H ₂ O and / or BaCl ₂ · 6H ₂ O is added as a flux to the raw material mixture. The addition amount of the flux can be determined so that the molar ratio of Sr in the raw material mixture is excessive by about 10%.

The firing atmosphere is usually a reducing atmosphere. When firing in a reducing atmosphere, Eu that was trivalent in the raw material is reduced to divalent. The gas used for the reducing atmosphere is hydrogen, carbon monoxide or the like, and is usually used by mixing with an inert gas such as nitrogen gas or rare gas. At this time, the ratio (molar ratio) of the reducing gas to the total amount of the gas is preferably 3% or more. The firing temperature (maximum temperature reached) is preferably 900 ° C. or higher and 1350 ° C. or lower, and the firing time is usually 1 hour or longer and 24 hours or shorter. The pressure during firing is preferably about atmospheric pressure. When a flux coexists in the reaction system in the firing step, good single particles can be grown. After the firing step, a pulverization step, a cleaning step, a classification step, a surface treatment step, a drying step and the like may be performed as necessary.

〔Experimental result〕
The results of experiments (including simulations) conducted by the present inventors will be described below. Table 1 shows a list of phosphors used in the experiment.

  Table 1 shows the name used in this specification, the type based on the emission color, the general formula, and the characteristics of the emission spectrum for each phosphor. As the characteristics of the emission spectrum, the peak wavelength (emission peak wavelength) and full width at half maximum of the emission spectrum and “relative intensity @ 580 nm” are shown. These are all values when excited at the wavelength indicated in parentheses in the column of emission peak wavelength. “Relative intensity @ 580 nm” is a value that relatively represents the intensity of the emission spectrum at a wavelength of 580 nm, where the intensity of the emission spectrum at the emission peak wavelength (emission peak intensity) is 1.

Among the phosphors shown in Table 1, SBCA-1 and SBCA-2, CASON-1 and CASON-2, and SCASN-1 and SCASN-2 are represented by the same general formula, but have different emission characteristics. Yes. The fact that the phosphors represented by the same general formula exhibit different light emission characteristics due to differences in the composition, activator concentration, impurity concentration, etc. of the matrix is well known in the art. Note that the general formulas of SBCA-1 and SBCA-2 can also be expressed as Sr _a Ba _b Eu _x (PO ₄ ) ₃ Cl (a + b = 5-x).

The blue phosphor SBCA-1 used in Examples 2 and 3 has a short-wavelength half-value wavelength of 437 nm and a long-wavelength half-value wavelength of 499 nm. Therefore, Δλ _L / Δλ _S = 2.9. Further, the blue phosphor SBCA-2 used in Example 4 has a short wavelength half-value wavelength of 438 nm and a long wavelength half-value wavelength of 496 nm. Therefore, similarly to SBCA-1, Δλ _L / Δλ _S = 2.9.

  Table 2 shows a list of white light emitting devices manufactured using the phosphors shown in Table 1. In the white light emitting devices according to Examples 1 to 4 and Comparative Example 1, a violet light emitting diode having an emission peak wavelength of about 405 nm is used as an excitation source of a phosphor. On the other hand, in the white light emitting devices according to Comparative Examples 2 to 4, a blue light emitting diode having an emission peak wavelength of about 450 nm is used as a light emitting element that serves both as a blue light component generation source and a phosphor excitation source. Each white light emitting device according to Examples and Comparative Examples was manufactured by mounting a light emitting diode in an SMD type package and sealing with a silicone resin composition in which a phosphor was dispersed. Table 2 shows the phosphor content (concentration) in the silicone resin composition used for the production of each white light emitting device. For example, in the white light emitting device of Example 1, a silicone resin composition containing blue phosphor BAM, green phosphor BSS, and red phosphor CASON-1 at concentrations of 13.3 wt%, 1.0 wt%, and 1.9 wt%, respectively. The violet light emitting diode is sealed with the object.

Table 3 shows the results of measuring the light emission characteristics of each of the white light emitting devices shown in Table 1. In Table 3, p (%) is the intensity at the wavelength λm of the spectrum of the color rendering index reference light normalized by the luminous flux when the minimum wavelength of the emission spectrum in the range of 460 to 520 nm is λm. This is the ratio of the intensity at the wavelength λm of the emission spectrum normalized by the luminous flux. Further, q (%) is the ratio of the intensity at the wavelength of 580 nm of the emission spectrum normalized by the light beam to the intensity at the wavelength of 580 nm of the spectrum of the reference light for color rendering properties normalized by the light beam. Therefore, 80 ≦ p ≦ 100 means that the first condition is satisfied, and 90 ≦ q ≦ 100 means that the second condition is satisfied.

  As shown in Table 3, the white light emitting devices according to Examples 1 to 4 satisfy both the first condition and the second condition, and the average color rendering index Ra and the special color rendering index R9, R10, R11. And R12 both exceed 80. Table 4 shows the color rendering indices R1 to R14 of the respective white light emitting devices according to the examples, and all exceed 80. In particular, the color rendering properties of the white light emitting devices of Examples 2 and 3 are extremely good, R1 to R14 are all 90 or more, and Ra is over 95. In the white light emitting devices of Examples 1 and 4, all the color rendering indexes except for R9 are 90 or more, and Ra is 95 or more.

The emission spectra of the white light emitting devices according to Examples 1 to 4 are shown in FIGS. The white light emitting device of Example 4 has an excellent special color rendering index R9 of 87 even though the maximum wavelength (maximum wavelength based on the emission of the red phosphor) of the emission spectrum on the longest wavelength side is as short as 608 nm. Value.
On the other hand, the white light emitting devices according to Comparative Examples 1 to 4 do not satisfy the first condition (80 ≦ p ≦ 100). Among these, the white light emitting devices of Comparative Examples 2 to 4 have low R12 values of 41, 57, and 66, respectively. The white light emitting device of Comparative Example 2 has a lower R10 (R10 = 32), but R10 of the white light emitting devices of Comparative Examples 3 and 4 exceeds 80. On the other hand, in the white light emitting device of Comparative Example 1, R12 exceeds 80 and R10 is a low value of 74. Such a difference can be attributed to the difference in the minimum wavelength of the emission spectrum in the wavelength range of 460 to 520 nm between the white light emitting device of Comparative Example 1 and the white light emitting devices of Comparative Examples 3 and 4. There is sex. The white light emitting device of Comparative Example 1 has the minimum wavelength at 499 nm, while the white light emitting devices of Comparative Examples 3 and 4 have the minimum wavelength at 489 nm and 484 nm, respectively.

  In order to confirm this, a virtual white light-emitting device that uses a spectrum obtained by combining a light emission spectrum of the white light-emitting device of Comparative Example 1 and a light emission spectrum of the white light-emitting device of Comparative Example 3 as a light emission spectrum by a simulation technique. The color rendering properties of were examined. Specifically, the emission spectra of the white light emitting devices of Comparative Examples 1 and 3 are each normalized by the luminous flux and added together at a predetermined ratio (A: B), and the resultant combined spectrum is obtained from the virtual white light emitting device. Considering the emission spectrum, average color rendering index Ra and special color rendering index R9 to R11 of the virtual white light emitting device were calculated. The results are shown in Table 5.

  As the ratio of the emission spectrum of the white light emitting device of Comparative Example 1 in the synthetic spectrum decreases, that is, as the total ratio A: B changes from 10: 0 to 0:10, the synthetic spectrum becomes The minimum wavelength in the wavelength range of 460 to 520 nm decreases from 499 nm to 485 nm. During this time, the first condition (80 ≦ p ≦ 100) is not satisfied, but as shown in Table 5, R10 of the hypothetical white light-emitting device having the synthetic spectrum as the emission spectrum goes from 74 to 84. On the contrary, R12 decreased from 81 to 57.

  Returning to Table 3 again, among the white light-emitting devices according to Comparative Examples 1 to 4, the white light-emitting devices of Comparative Examples 1 and 3 satisfy the second condition (90 ≦ q ≦ 100). The color rendering index R9 is a high value of 90 or more. On the other hand, the white light emitting devices of Comparative Examples 2 and 4 do not satisfy the second condition, and their R9 values are extremely low values of −34 and 45, respectively.

10, 20, 30 Semiconductor white light emitting device 11, 21, 31 Package 12, 22, 32 Semiconductor light emitting element 13, 23, 33 Wavelength converter 34 Transparent member S Space

Claims (23)

A semiconductor light emitting device, and a wavelength converter that absorbs light emitted from the semiconductor light emitting device and emits light having a wavelength different from that emitted from the semiconductor light emitting device, and applying a current to the semiconductor light emitting device, A semiconductor white light emitting device that emits white light having a correlated color temperature in a range of 5000 to 7000 K including light emitted from the wavelength conversion unit,
The emission spectrum has a minimum wavelength in the wavelength range of 460 to 520 nm,
The intensity at the minimum wavelength of the emission spectrum normalized by the luminous flux is 80 to 100% of the intensity at the minimum wavelength of the spectrum of the color rendering property reference light normalized by the luminous flux,
A semiconductor white light emitting device characterized in that the intensity at a wavelength of 580 nm of an emission spectrum normalized by a light beam is 90 to 100% of the intensity at a wavelength of 580 nm of a spectrum of reference light for color rendering properties normalized by a light beam.   The semiconductor white light emitting device according to claim 1, wherein the wavelength conversion unit includes a blue phosphor, a green phosphor, and a red phosphor that are excited by the semiconductor light emitting element to emit light.   The blue phosphor includes an Eu-activated alkaline earth halophosphate phosphor having a peak wavelength of an emission spectrum in a range of 450 to 460 nm and a half-value wavelength on the long wavelength side of 490 nm or more. Semiconductor white light emitting device.   The semiconductor white light-emitting device according to claim 3, wherein the green phosphor includes at least one of an alkaline earth silicate nitride phosphor and a sialon phosphor.   4. The semiconductor white light emitting device according to claim 3, wherein the green phosphor includes a phosphor having an emission spectrum peak wavelength in a range of 535 to 550 nm and a full width at half maximum of 50 to 70 nm.   The semiconductor according to claim 5, wherein the phosphor having a peak wavelength of the emission spectrum in a range of 535 to 550 nm and a full width at half maximum of 50 to 70 nm includes an alkaline earth silicate nitride phosphor or a sialon phosphor. White light emitting device.   The semiconductor white light emitting device according to claim 6, wherein the phosphor having a peak wavelength of the emission spectrum in a range of 535 to 550 nm and a full width at half maximum of 50 to 70 nm includes a β sialon phosphor.   The semiconductor white light emitting device according to claim 7, wherein the red phosphor includes a phosphor having an emission spectrum peak wavelength of 620 nm or less.   The semiconductor white light emitting device according to claim 8, wherein the phosphor having a peak wavelength of the emission spectrum of 620 nm or less includes an Eu-activated alkaline earth siliconitride phosphor containing Sr and Ca.   10. The semiconductor white light emitting device according to claim 1, wherein the correlated color temperature of the white light is 6000 K or more, and the maximum wavelength of the emission spectrum on the longest wavelength side is 610 nm or less. A semiconductor light emitting device, and a wavelength converter that absorbs light emitted from the semiconductor light emitting device and emits light having a wavelength different from that emitted from the semiconductor light emitting device, and applying a current to the semiconductor light emitting device, A semiconductor white light emitting device that emits white light having a correlated color temperature in a range of 5000 to 7000 K including light emitted from the wavelength conversion unit,
The average color rendering index Ra is 95 or more,
A semiconductor white light emitting device characterized in that the special color rendering index R9, R10, R11 and R12 is 85 or more.   The semiconductor white light emitting device according to claim 11, wherein the correlated color temperature of the white light is in a range of 5000 to 6000K, and all of the color rendering indexes R1 to R14 are 90 or more.   The semiconductor white light emitting device according to claim 11, wherein the correlated color temperature of the white light is 6000 or more and all of the color rendering indexes R1 to R14 are 85 or more.   The semiconductor white light emitting device according to claim 11, wherein the wavelength conversion unit includes a blue phosphor, a green phosphor, and a red phosphor that are excited by the semiconductor light emitting element to emit light.   The blue phosphor includes an Eu-activated alkaline earth halophosphate phosphor having a peak wavelength of an emission spectrum in a range of 450 to 460 nm and a half-value wavelength on the long wavelength side of 490 nm or more. Semiconductor white light emitting device.   The semiconductor white light emitting device according to claim 15, wherein the green phosphor includes a phosphor having an emission spectrum peak wavelength in a range of 535 to 550 nm and a full width at half maximum of 50 to 70 nm.   17. The semiconductor white light emitting device according to claim 16, wherein the green phosphor includes an alkaline earth silicate nitride phosphor having an emission spectrum peak wavelength in a range of 535 to 550 nm and a full width at half maximum of 50 to 70 nm. .   The semiconductor white light emitting device according to claim 16, wherein the green phosphor includes a sialon phosphor having a peak wavelength of an emission spectrum in a range of 535 to 550 nm and a full width at half maximum of 50 to 70 nm.   The semiconductor white light emitting device according to claim 18, wherein the green phosphor includes a β sialon phosphor. A semiconductor light emitting device, and a wavelength converter that absorbs light emitted by the semiconductor light emitting device and emits light having a wavelength different from that of the light emitted by the semiconductor light emitting device,
The wavelength conversion unit includes a blue phosphor, a green phosphor, and a red phosphor that are excited by the semiconductor light emitting element to emit light. By applying a current to the semiconductor light emitting element, light emitted from the wavelength conversion unit is generated. White light having a correlated color temperature in the range of 6000 to 7000 K is emitted,
The average color rendering index Ra is 95 or more,
The semiconductor white light emitting device, wherein the special color rendering index R9, R10, R11, and R12 is 85 or more, and the maximum wavelength of the emission spectrum on the longest wavelength side is 610 nm or less.   21. The blue phosphor includes an Eu-activated alkaline earth halophosphate phosphor having a peak wavelength of an emission spectrum in a range of 450 to 460 nm and a half-value wavelength on the long wavelength side of 490 nm or more. Semiconductor white light emitting device.   The semiconductor white light emitting device according to claim 20 or 21, wherein the green phosphor contains β sialon: Eu.   The semiconductor white light emitting device according to any one of claims 20 to 22, wherein the red phosphor includes an Eu-activated alkaline earth siliconitride phosphor containing Sr and Ca.

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