JP2013012778A - Lighting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor light-emitting device having a correlated color temperature of 1600 K or more and less than 2400 K and producing high Ra light, and provide a semiconductor light-emitting system including the semiconductor light-emitting device.SOLUTION: A semiconductor light-emitting device 1 comprises: an LED chip 10 as a semiconductor light-emitting element; and a phosphor 20 emitting light using the LED chip 10 as an excitation source. The semiconductor light-emitting device 1 generates light having a correlated color temperature of 1600 K or more and less than 2400 K. The phosphor 20 includes at least a green phosphor and a red phosphor. In a spectrum of light generated by the semiconductor light-emitting device 1, a value of a peak light intensity of light generated by the LED chip 10 is set at less than 60% of a peak light intensity of light generated by the phosphor 20.

Description

  The present invention relates to a semiconductor light emitting device, a semiconductor light emitting system including the semiconductor light emitting device, and a lighting fixture including the semiconductor light emitting device, and more particularly, semiconductor light emitting that emits light having a correlated color temperature of 1600K or higher and lower than 2400K. The present invention relates to an apparatus, a semiconductor light emitting system including the semiconductor light emitting device, and a lighting fixture including the semiconductor light emitting device.

  Incandescent light bulbs and fluorescent lamps have been widely used as light sources for lighting devices. In recent years, in addition to these, lighting devices using semiconductor light emitting elements such as LEDs and organic EL (OLED) as a light source have been developed and used. Since these semiconductor light emitting elements can obtain various emission colors, a plurality of semiconductor light emitting elements having different emission colors are combined, and the respective emission colors are combined to obtain a desired color of emitted light. Such lighting devices are also being developed and used.

  In Patent Document 1, a violet light-emitting diode element is used, a semiconductor that emits light having a correlated color temperature of about 2700K or higher and 4000K or lower, and an average color rendering index Ra (hereinafter simply referred to as Ra) of 80 or higher. An example of a light emitting device is described.

  Patent Document 2 describes a pseudo-flame type light emitting device having an outer core portion, an inner flame portion, and an outer flame portion resembling the shape of a candle flame. The color temperature of the external flame part of the apparatus described in Patent Document 2 is 1000 to 2200K. The device described in Patent Document 2 includes a light emitting element that emits blue light at the core part in order to set the color temperature of the outer flame part to a range of 1000 to 2200K, and the outer flame part has a yellow to yellow-red color. It is described that it comprises a phosphor that emits light (specifically, a YAG (Yttrium Aluminum Garnet) phosphor).

  Patent Document 3 describes a lighting device that emits light having a correlated color temperature of about 1500 K and resembles a candle and a flame of the candle. The lighting device described in Patent Document 3 includes a light source module including two light emitting elements. The two light emitting elements each have a plurality of light emitting unit layers that emit monochromatic light of various wavelengths, and by adjusting the light emission intensity at each wavelength according to the number of layers and the layer thickness of the light emitting unit layers, Ra is increased by bringing the emission spectrum distribution closer to the distribution in the sunlight spectrum.

  Patent Document 4 describes a light emitting device that includes a blue LED having a peak wavelength of 470 to 480 nm and a fluorescent material having a peak wavelength of 600 ± 3 nm and emits light having a color temperature of 1900 to 2100K.

  Patent Document 5 describes a light source that includes a blue GaN (Gallium Nitride) LED, a red quantum dot material, and a yellow green phosphor material, and emits light having a color temperature of 1000 to 16000K. Patent Document 5 describes that the color rendering index (CRI (Color Rendering Index)) can be set to a desired value by selecting and configuring the LED, the quantum dot material, and the phosphor material. .

  Patent Document 6 describes an LED illumination lamp in which three blue LEDs having a peak wavelength of about 480 nm are used as a light source, and phosphors applied to the blue LEDs each emit fluorescence. In the LED illumination lamp described in Patent Document 6, green phosphor and red phosphor are mixed and applied to two blue LEDs of three blue LEDs, and yellow phosphor is applied to the remaining one blue LED. Has been. And the LED illumination lamp described in patent document 6 radiates | emits the synthetic | combination light of the blue light which each blue LED emits, and the fluorescence which each fluorescent substance emits outside.

  Patent Document 7 includes a purple LED and a light emitting body in which a blue phosphor, a green phosphor, and a red phosphor, each emitting fluorescence obtained by wavelength-converting a part of light emitted from the purple LED, are mixed. A lighting device is described. The illuminating device described in Patent Document 7 emits the combined light of the light emitted from the purple LED and the fluorescence emitted from the light emitter.

International Publication No. 2011/024818 JP 2005-78905 A JP 2004-128443 A JP 2009-64999 A Special table 2008-544553 gazette JP 2009-123429 A International Publication No. 2008/001799

  When a semiconductor light-emitting device using a semiconductor light-emitting element such as an LED as a light source is used as an illumination device for indoor lighting such as indirect lighting, candle light with a high value of Ra (specifically, the correlated color temperature is 1600 K or more) And light that is less than 2400K, preferably less than 2000K).

  However, Patent Document 1 does not describe an apparatus that emits light having a correlated color temperature of 1600K or higher and lower than 2400K.

  Further, Patent Document 2 and Patent Document 4 do not describe a configuration for increasing Ra and a study for such a configuration.

  The lighting device described in Patent Document 3 emits light emitted only by a special light-emitting element, so that a circuit for controlling the output of the light-emitting element is necessary, and costs such as manufacturing are required. There's a problem. In addition, the light emitted from the light emitting element has a strong directivity, so that there is a problem that color separation is easy.

  Patent Document 5 does not describe a configuration for increasing Ra in a device that emits light having a correlated color temperature of 1600 K or higher and lower than 2400 K, or a study for such a configuration.

  The LED illumination lamp described in Patent Document 6 has a problem in that light emission efficiency is low because a blue LED that emits light having a longer wavelength than a violet LED is used as a light emission source. In addition, since a mixed phosphor is applied to one blue LED so that light containing a large amount of a red component is emitted, it is not possible to emit candle light having a sufficiently high Ra.

  The lighting device described in Patent Document 7 has improved color rendering in the red region, but describes a method for further improving the color rendering of candle light, which is light having a lower correlated color temperature. It has not been.

  In the techniques described in Patent Documents 1 to 7, the sensation as the appearance of the light source is insufficient as compared with a real candle, and it feels unnatural as a candle color because it is tinged with blue or the like. Emits light.

  The present invention has been made in view of the problems as described above. The object of the present invention is light having a correlated color temperature of 1600K or higher and lower than 2400K, preferably lower than 2000K, and a high Ra, that is, color rendering. An object of the present invention is to provide a semiconductor light emitting device that emits light with excellent properties, a semiconductor light emitting system including the semiconductor light emitting device, and a lighting fixture including the semiconductor light emitting device.

  In order to achieve the above object, a semiconductor light emitting device of the present invention includes a semiconductor light emitting element and a phosphor that emits light using the semiconductor light emitting element as an excitation source, and has a correlated color temperature of 1600K or higher and lower than 2400K, preferably 2000K. In a semiconductor light emitting device that emits light that is less than, the phosphor includes at least a green phosphor and a red phosphor, and in the spectrum of light emitted from the semiconductor light emitting device, the peak intensity of light emitted by the semiconductor light emitting element Is a value less than 60% of the maximum peak intensity of the light emitted from the phosphor.

  As the semiconductor light emitting element, a purple light emitting diode element is preferably used, and a semiconductor light emitting element that emits light having an emission peak of 380 nm or more and 430 nm or less is preferably used. When a violet light-emitting diode element or a semiconductor light-emitting element that emits light having an emission peak of 380 nm or more and 430 nm or less is used, the semiconductor light-emitting device includes a blue phosphor, a green phosphor, and a red phosphor. It is preferable.

  The peak intensity value of light emitted by the semiconductor light emitting element of the semiconductor light emitting device is a value less than 60% of the maximum peak intensity of light emitted from the phosphor, and the maximum peak is 600 nm or more and 660 nm or less. Preferably it is located.

  According to the semiconductor light emitting device configured as described above, the correlated color temperature is 1600K or higher, preferably 1700K or higher and lower than 2400K, preferably lower than 2000K, and can emit light with high Ra.

  It is preferable to emit light having a spectrum such that the peak intensity value of light emitted by the semiconductor light emitting element is 5% or more of the maximum peak intensity of light emitted from the phosphor. According to such a configuration, the Ra value and the luminous efficiency value can be made compatible at a high level.

The blue phosphor may be configured such that the half-value width of the emission peak wavelength is 30 nm or more, and the blue phosphor is (Sr, Ba, Ca) ₅ (PO ₄ ) ₃ Cl: Eu, or BaMgAl _10. O ₁₇ : Eu may be used.

  In the XY chromaticity diagram of the CIE (1931) XYZ color system, the chromaticity coordinates of the light emitted from the semiconductor light emitting device have a deviation duv from the black body radiation locus curve of -0.02 or more and 0. You may be comprised so that it may be 02 or less.

The green phosphor may be β sialon, (Ba, Sr) ₃ Si ₆ O ₁₂ N ₂ : Eu, or (Sr, Ba) ₂ SiO ₄ : Eu, and the red phosphor may be (CaAlSiN ₃ ). _1-x (Si ₂ N ₂ O) _x : Eu (x is 0 <x <0.5) may be included.

Red phosphor, K ₂ SiF _6: may contain an Mn, at _{A 2 + x M y Mn Z} F n (A is one or both Na and K Tonouchi .M is Si and Al And ≦ 1 ≦ x ≦ 1, 0.9 ≦ y + z ≦ 1.1, 0.001 ≦ z ≦ 0.4, and 5 ≦ n ≦ 7).

  The phosphor may be configured to transmit the light emitted by the semiconductor light emitting element with a predetermined transmittance and to emit the light to the outside of the semiconductor light emitting device.

  A phosphor layer that includes a holding member that holds phosphors, the holding member holding each color phosphor in a predetermined region set for each color, and a region that holds the phosphor for each color. The phosphor layer may be supported so that the distance from the semiconductor light emitting element is 0.1 mm or more and 500 mm or less. According to such a configuration, cascade excitation that occurs when phosphors of respective colors are mixed can be prevented.

  The semiconductor light emitting system according to the present invention includes a semiconductor light emitting device having any of the above-described features as the first semiconductor light emitting device, and the second semiconductor light emitting device correlates with light emitted by the first semiconductor light emitting device. A semiconductor light emitting device that emits light having different color temperatures is provided.

  According to such a configuration, the correlated color temperature of the light emitted from the semiconductor light emitting system is between the correlated color temperature of the light emitted from the first semiconductor light emitting device and the correlated color temperature of the light emitted from the second semiconductor light emitting device. Can be adjusted.

  The average color rendering index Ra of the first semiconductor light emitting device may be 86 or more, and the average color rendering index Ra of the second semiconductor light emitting device may be 86 or more. According to such a configuration, the variation in the average color rendering index Ra when the color temperature is adjusted in the semiconductor light emitting system can be reduced.

  A lighting fixture according to the present invention includes a semiconductor light emitting device having any of the above-described features.

  According to the semiconductor light emitting device of the present invention, the correlated color temperature is 1600K or more and less than 2400K, preferably less than 2000K, emits light with a large Ra value, that is, light with excellent color rendering properties, and has a blue color. Without it, it can emit light that does not feel unnatural as a candle color. Further, the light emitted by the semiconductor light-emitting element can be obtained without complicated adjustment of the mixing ratio of the respective phosphors such as the green phosphor and the red phosphor and the selection of each phosphor only for the purpose of increasing Ra. By adjusting the ratio between the peak intensity value and the maximum peak intensity of the light emitted from the phosphor, the Ra value can be increased.

It is a schematic explanatory drawing which shows the structural example of the semiconductor light-emitting device by this invention. It is a graph which shows the emission spectrum of LED chip, green fluorescent substance, red fluorescent substance, and blue fluorescent substance. It is a graph which shows the simulation result of the emission spectrum of the semiconductor light-emitting device in which the sample from which each excitation light ratio differs was used. It is a table | surface which shows the simulation result of Ra according to the change of the excitation light ratio. It is a graph which shows the simulation result of Ra according to the change of the excitation light ratio. It is a table | surface which shows the ratio of the fluorescent substance of each color in each experimental sample from which an excitation light ratio differs, and a sealing material. It is a graph which shows the emission spectrum of the semiconductor light-emitting device using each experimental sample from which the excitation light ratios mutually differ shown in FIG. It is a table | surface which shows the change of the optical characteristic according to the change of an excitation light ratio using each experimental sample shown in FIG. It is a table | surface which shows the ratio of the fluorescent substance of each color and sealing material in another experimental sample. It is a table | surface which shows the optical characteristic of the other experimental sample shown in FIG. It is the schematic which shows the structure of the semiconductor light-emitting device in which the fluorescent substance layer was formed. It is a schematic explanatory drawing which shows the example of the semiconductor light-emitting system containing the semiconductor light-emitting device which emits the light from which correlation color temperature differs mutually. It is explanatory drawing which shows the other example of the semiconductor light-emitting system containing the semiconductor light-emitting device which emits the light from which correlation color temperature differs mutually. It is a schematic sectional drawing which shows the structural example of the lighting fixture containing the semiconductor light-emitting device of embodiment mentioned above.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the content demonstrated below, In the range which does not deviate from the summary, it can change arbitrarily and can implement. In addition, the drawings used in the description of the present embodiment all schematically show the characteristics of the semiconductor light emitting device 1 and the like according to the present invention, and in order to deepen the understanding, partial emphasis, enlargement, In some cases, reduction or omission is performed. Furthermore, the various numerical values used are merely examples, and can be changed variously as necessary.

  FIG. 1 is a schematic explanatory diagram illustrating a configuration example of a semiconductor light emitting device 1 according to an embodiment of the present invention. As shown in FIG. 1, a semiconductor light emitting device 1 according to an embodiment of the present invention includes an LED chip 10 that is a semiconductor light emitting element, and a phosphor 20 that converts the wavelength of light emitted from the LED chip 10. Then, a combined light having a correlated color temperature of 1600K or higher and lower than 2400K, preferably lower than 2000K is emitted.

  As the LED chip 10, a blue light emitting diode element or a purple light emitting diode element is used. As the LED chip 10, the phosphor 20 used is different depending on whether a blue light-emitting diode element is used or a violet light-emitting diode element is used. In addition, it is preferable that a purple light emitting diode element is used as the LED chip 10.

(Combination of LED chip 10 and phosphor 20)
When the LED chip 10 is a blue light emitting diode element, the phosphor 20 includes at least a green phosphor and a red phosphor. Then, usually, a part of the blue light emitted from the LED chip 10 which is a blue light emitting diode element, a green light in which another part of the blue light is wavelength-converted by the green phosphor, and another blue light. Part of which includes red light that has been wavelength-converted by a red phosphor as a component, and emits synthesized light having a correlated color temperature of 1600K or higher and lower than 2400K, preferably lower than 2000K. Generally, the emission peak wavelength of a blue light emitting diode element is 440 to 470 nm. The phosphor 20 may include a yellow phosphor that emits yellow light by converting the wavelength of part of the blue light emitted from the blue light emitting diode element.

  When the LED chip 10 is a violet light emitting diode element, the phosphor 20 includes a green phosphor, a red phosphor, and a blue phosphor. In general, ultraviolet light or purple light emitted from the LED chip 10 that is a violet light-emitting diode element and a part of ultraviolet light or purple light emitted from the LED chip 10 that is a violet light-emitting diode element are blue fluorescent. Blue light wavelength-converted by the body, green light whose wavelength is converted by the green phosphor by ultraviolet light or other part of the purple light, and another part of the ultraviolet light or purple light wavelength by the red phosphor Combined red light is included as a component, and synthetic light having a correlated color temperature of 1600K or higher and lower than 2400K, preferably lower than 2000K is emitted.

  In the present embodiment, the peak intensity of light (also referred to as excitation light) emitted by the LED chip 10 in the emission spectrum of the synthesized light having a correlated color temperature of 1600K or higher and lower than 2400K, preferably lower than 2000K, By configuring the LED chip 10 and the phosphor 20 so that the value of the ratio of the maximum peak intensity of the light (also referred to as fluorescence) emitted from the phosphor 20 excited by the excitation light is within a predetermined range, Ra can be obtained. Increase. Note that the percentage of the ratio of the peak intensity of the excitation light to the maximum peak intensity of fluorescence is referred to as the excitation light ratio.

  In the present embodiment, the reason why the Ra of the synthesized light emitted by the semiconductor light emitting device 1 is increased by adjusting the excitation light ratio will be described. When the correlated color temperature of the synthesized light emitted by the white light source is lowered, the light emitted by the white light source is reddish, and the proportion of the spectrum in the short wavelength region (for example, the region where the wavelength is 450 nm or less) is reduced in the emission spectrum. To do. In the visible light region of the spectrum of black body radiation, which is the reference light, the proportion of the spectrum of 450 nm or less in the spectrum of light having a correlated color temperature of 2700 K and the wavelength of 450 nm or less in the emission spectrum of light having a correlated color temperature of 1900 K This will be described in comparison with the spectrum ratio. The light having a correlated color temperature of 2700 K is, for example, light emitted by an incandescent light bulb used for illumination (hereinafter also referred to as light bulb color light). The light having a correlated color temperature of 1900K is, for example, light emitted by a candle flame (hereinafter also referred to as candle light).

In the above formula (1),
λ: wavelength [m]
T: Color temperature [K]
k: Boltzmann constant [J · K ⁻¹ ]
h: Planck's constant [J · s]
c: speed of light [m / s]
Suppose that

  When the ratio of the integral value of the spectrum of the wavelength of 450 nm or less occupying the integral value of the spectrum in the visible light region is calculated using the above formula (1), the spectrum of the wavelength of 450 nm or less of the light having the correlated color temperature of 2700 K is calculated. The ratio of the integral value is 2.5%, and the ratio of the integral value of the spectrum having a wavelength of 450 nm or less of the light having the correlated color temperature of 1900 K is 0.4%. That is, the ratio of the integral value of the spectrum having a wavelength of 450 nm or less of light having a correlated color temperature of 1900K is equal to or less than one sixth of the ratio of the spectrum having a wavelength of 450 nm or less of light having a correlated color temperature of 2700K. In comparison with light bulb light, candle light has a lower spectrum ratio of light having a wavelength of 450 nm or less.

  Therefore, when creating a white lamp using a blue light emitting diode element or a purple light emitting diode element as an excitation source, the excitation intensity (the intensity of the light emitted by the excitation source) of the combined light of the bulb color and the combined light of the candle color. If the intensity is the same, the ratio of the spectrum of the excitation light in the spectrum of the wavelength of 450 nm or less is higher in the ratio of the combined light of the candle color than the ratio of the combined light of the bulb color. In other words, the influence of the excitation light on the correlated color temperature in the combined light of the candle color is larger than the influence of the excitation light on the correlated color temperature in the combined light of the bulb color. Therefore, it is important to adjust the excitation light in the candle light.

  For example, when a purple light-emitting diode element, a red phosphor, a green phosphor, and a blue phosphor are used as light sources to emit a candle-colored composite light, the correlated color temperature of the composite light emitted is set to In order to obtain the correlated color temperature, it is necessary to reduce the blending amount of the blue phosphor that emits light of a short wavelength than that of the light bulb color. However, in such a case, the spectral intensity in the blue region due to fluorescence in the white spectrum of the light source is weaker than the black body radiation spectrum that is the standard for color rendering. In the blue region, the spectrum of the excitation light having a narrow bandwidth emitted by the violet light-emitting diode element remains regardless of the fact that the fluorescence spectrum intensity becomes weak, so that the color rendering property is lowered. That is, Ra is lowered and light with high color rendering properties cannot be emitted.

  Therefore, in the case of emitting a candle color combined light having a correlated color temperature of 1600K or higher and less than 2400K, preferably less than 2000K, a daylight color combined light having a correlated color temperature of about 6500K or a light bulb of about 2700K. It is difficult to increase Ra by adjusting the mixing ratio of the red phosphor, the green phosphor, and the blue phosphor or selecting each phosphor, which is a method that can be used when emitting combined light of colors. Therefore, in the present embodiment, Ra is increased by adjusting the excitation light ratio.

  Here, specific examples of each phosphor described above will be described below. These phosphors are examples of suitable phosphors in the present embodiment, but applicable phosphors are not limited to the following, and various types can be used without departing from the gist of the present invention. It is possible to apply the phosphors.

(Green phosphor)
The emission peak wavelength of the green phosphor is usually 500 nm or more, preferably 510 nm or more, more preferably 515 nm or more, and usually less than 550 nm, preferably 542 nm or less. Among them, as the green phosphor, for example, (Y, Lu) ₃ (Al, Ga) ₅ O ₁₂ : Ce, CaSc ₂ O ₄ : Ce, Ca ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce, (Sr , Ba) ₂ SiO ₄ : Eu (BSS), (Si, Al) ₆ (O, N) ₈ : Eu (β-sialon), (Ba, Sr) ₃ Si ₆ O ₁₂ N ₂ : Eu (BSON), SrGa ₂ S ₄ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, Mn are preferable. The half-value width of the emission peak wavelength of the green phosphor is preferably 50 nm or more, and more preferably 65 nm or more. By using a green phosphor having a broad emission peak, the color rendering properties tend to be improved even when a blue phosphor having a narrow half-value width is used.

(Red phosphor)
The emission peak wavelength of the red phosphor is usually 570 nm or more, preferably 580 nm or more, more preferably 585 nm or more, and usually 780 nm or less, preferably 700 nm or less, more preferably 680 nm or less. is there. Among them, as red phosphors, for example, CaAlSiN ₃ : Eu, CaAlSi (N, O) ₃ : Eu (hereinafter, referred to as “CASON” phosphors) (CaAlSiN ₃ ) _1-x (Si ₂ N ₂ O ) _X : Eu (x may be described as 0 <x <0.5)), (Ca, Sr) AlSiN ₃ : Eu (hereinafter, referred to as “SCASN” phosphor) (Ca, Sr, Ba) AlSi (N, O) ₃ : Eu), (Ca, Sr, Ba) ₂ Si ₅ (N, O) ₈ : Eu, (Ca, Sr, Ba) Si ( N, O) ₂ : Eu, (Ca, Sr, Ba) AlSi (N, O) ₃ : Eu, (Sr, Ba) ₃ SiO ₅ : Eu, (Ca, Sr) S: Eu, SrAlSi ₄ N ₇ : Eu, (La, Y) ₂ O ₂ S: Eu, Eu (dibenzoylmethane) ₃ · 1, 10 -Β-diketone Eu complex such as phenanthroline complex, carboxylic acid Eu complex, K ₂ SiF ₆ : Mn, Mn activated germanate is preferred, (Ca, Sr, Ba) ₂ Si ₅ (N, O) ₈ : Eu, (Sr, Ca) AlSi (N, O) ₃ : Eu, SrAlSi ₄ N ₇ : Eu, (La, Y) ₂ O ₂ S: Eu, K ₂ SiF ₆ : Mn (however, a part of Si May be substituted with Al or Na), Mn-activated germanate is more preferable.

(Blue phosphor)
The emission peak wavelength of the blue phosphor is usually 420 nm or more, preferably 430 nm or more, more preferably 440 nm or more, usually less than 500 nm, preferably 490 nm or less, more preferably 480 nm or less, still more preferably 470 nm or less, particularly preferably. Is preferably in the wavelength range of 460 nm or less. Among them, as the blue phosphor, for example, (Ca, Sr, Ba) MgAl ₁₀ O ₁₇ : Eu, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ (Cl, F) ₂ : Eu, (Ba, Ca , Mg, Sr) ₂ SiO ₄ : Eu, (Ba, Ca, Sr) ₃ MgSi ₂ O ₈ : Eu are preferred, and (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu, (Ca, Sr, Ba) ₁₀ (PO ₄ ) ₆ (Cl, F) ₂ : Eu, Ba ₃ MgSi ₂ O ₈ : Eu is more preferable, Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, BaMgAl ₁₀ O ₁₇ : Eu is more preferable, (Sr _{1− x Ba x) 5 (PO 4} ) 3 Cl: Eu (x> 0) is particularly preferred. The full width at half maximum of the emission peak wavelength of the blue phosphor is preferably 30 nm or more, more preferably 40 nm or more, still more preferably 50 nm or more, and particularly preferably 60 nm or more.

(Yellow phosphor)
The emission peak wavelength of the yellow phosphor is usually 530 nm or more, preferably 540 nm or more, more preferably 550 nm or more, and usually 620 nm or less, preferably 600 nm or less, more preferably 580 nm or less. is there. Among them, as the yellow phosphor, for example, Y ₃ Al ₅ O ₁₂ : Ce, (Y, Gd) ₃ Al ₅ O ₁₂ : Ce, (Sr, Ca, Ba, Mg) ₂ SiO ₄ : Eu, (Ca, Sr) Si ₂ N ₂ O ₂ : Eu, α-sialon, La ₃ Si ₆ N ₁₁ : Ce (however, a part thereof may be substituted with Ca or O) are preferable.

  The phosphor 20 may be in the form of a powder or a luminescent ceramic containing a phosphor phase in a ceramic structure. The powdered phosphor is preferably fixed by dispersing phosphor particles in a transparent fixing matrix made of a polymer material or glass, or by electrodeposition or other methods on the surface of an appropriate member. The phosphor particles are fixed in a layered manner. When light (specifically, excitation light) emitted by the LED chip 10 is emitted to the outside of the semiconductor light emitting device 1, the phosphor 20 transmits the light with a predetermined transmittance. Therefore, the excitation light ratio is also referred to as excitation light transmittance.

  By appropriately combining the phosphors and the like exemplified above, it is possible to adjust the wavelength and intensity of the maximum peak in the spectrum of light emitted from the light emitting device 1. The wavelength and intensity of the maximum peak in the spectrum of light emitted from the light emitting device 1 according to the present invention are not particularly limited as long as the specific excitation light ratio of the present invention is satisfied, but the wavelength of the maximum peak in the spectrum of light emitted from the light emitting device 1 Is 600 nm or more and 660 nm or less, so that it is easy to achieve so-called candle-colored synthesized light, and preferably the maximum peak wavelength is 610 nm or more and 660 nm or less.

(LED chip 10)
The LED chip 10 is preferably a semiconductor light emitting element that emits light of 360 to 490 nm. Examples of such a semiconductor light emitting element include a blue light emitting diode element and a purple light emitting diode element. The semiconductor light emitting device is preferably a light emitting diode device having a pn junction type light emitting portion formed of a nitrogen gallium based, zinc oxide based or silicon carbide based semiconductor.

  It is preferable that the light emission peak wavelength of the LED chip 10 is configured to be 380 to 420 nm. The reason why the emission peak wavelength of the LED chip 10 is preferably 380 nm or more is because the difference between the excitation wavelength of the phosphor 20 (excitation light wavelength) and the phosphor emission wavelength is large, and the energy due to the Stokes shift. This is because the loss increases and the light emission efficiency of the semiconductor light emitting device 1 (more specifically, the phosphor 20) decreases. Note that when the light emitted by the LED chip 10 does not include visible component light (light having a wavelength of 380 to 780 nm), the light emitted by the LED chip 10 is the light emitted from the semiconductor light emitting device 1. Since the correlated color temperature and chromaticity are not directly affected, even if the excitation light ratio is changed, Ra does not change.

  The reason why the emission peak wavelength of the LED chip 10 is preferably 420 nm or less is that light emitted by the LED chip 10 (for example, a blue light emitting diode element) having an emission peak wavelength longer than 420 nm has a blue component. This is because a large amount is included, and in order to adjust the excitation light ratio, it is necessary to largely change the blending ratio of the green phosphor and the red phosphor. When the LED chip 10 having an emission peak wavelength of 420 nm or less (for example, a violet light emitting diode element) is used, the phosphor 20 is not greatly changed without greatly changing the mixing ratio of the green phosphor, the red phosphor, and the blue phosphor. The excitation light ratio can be adjusted by adjusting the ratio between the total amount of the phosphor and the amount of the resin for sealing the phosphor 20 inside the semiconductor light emitting device 1.

  In addition, when a blue light emitting diode element is used, the light emitted from the blue light emitting diode element contains a large amount of blue component when the emission peak wavelength fluctuates due to heat generation or the like of the blue light emitting diode element. As a result, the chromaticity and color temperature of light emitted from the semiconductor light emitting device may change. On the other hand, when a purple light emitting diode element is used, even if the emission peak wavelength of the purple light emitting diode element fluctuates, it is possible to suppress changes in the chromaticity and color temperature of light emitted from the semiconductor light emitting device. it can. In addition, the emission peak wavelength of the semiconductor light emitting element may differ due to different manufacturing lots of the semiconductor light emitting element. However, when a purple light emitting diode element is used, the emission peak wavelength of the purple light emitting diode element varies. Even if it does, since the change of the chromaticity and color temperature of the light which a semiconductor light-emitting device emits is few, the yield at the time of manufacturing a semiconductor light-emitting device can be made favorable.

  In addition, when a purple light emitting diode element is used, the variation in chromaticity when the amount of current flowing through the element is changed is smaller than when a blue light emitting diode element is used. It can be used suitably for a system.

  As a method of adjusting the excitation light ratio in the synthesized light emitted by the semiconductor light emitting device 1, a method of changing the blending ratio of the green phosphor, the red phosphor and the blue phosphor according to the LED chip 10, and the phosphor 20. Although the method of adjusting the ratio of the total amount of resin and the amount of resin for sealing the phosphor 20 inside the semiconductor light emitting device 1 has been described, the excitation light ratio may be adjusted by other methods. Specifically, for example, light having a wavelength other than the wavelength of the excitation light is allowed to pass through a path through which the synthesized light emitted by the self-semiconductor light-emitting device 1 in the semiconductor light-emitting device 1 is emitted to the outside or a path through which the excitation light passes. Filter (bandpass filter), filter that does not allow light having a wavelength shorter than the wavelength of the excitation light (UV cut filter), filter that does not allow light having the wavelength of the excitation light to pass or is reduced at a predetermined rate (band elimination) (Nation filter) may be installed.

<Experimental sample>
A sample (semiconductor light emitting device 1 of the present embodiment) of an experiment (including simulation) conducted by the inventors of the present invention will be described. In this experiment, a violet light-emitting diode element having an emission peak wavelength of 405 nm and a half-value width of 30 nm is used as the LED chip 10. Note that the emission peak wavelength and the half width are measured using an integrating sphere. In addition, β-sialon is used as the green phosphor, CaAlSi (N, O) ₃ : Eu (CASON) is used as the red phosphor, and (Sr _1-x Ba _x ) ₅ (PO ₄ ) as the blue phosphor. ₃ Cl: Eu (x> 0) is used. The emission peak wavelength of the green phosphor is 540 nm and the half width is 60 nm, the emission peak wavelength of the red phosphor is 640 nm and the half width is 115 nm, and the emission peak wavelength of the blue phosphor is 475 nm and half. The value width is 80 nm. The emission peak wavelength and half-value width of each phosphor are values measured with a spectrophotometer.

  FIG. 2 is a graph showing emission spectra of the LED chip 10, the green phosphor, the red phosphor, and the blue phosphor. In FIG. 2, the emission spectrum of the LED chip 10 is indicated by a solid line, the emission spectrum of the green phosphor is indicated by a one-dot chain line, the emission spectrum of the red phosphor is indicated by a broken line, and the emission spectrum of the blue phosphor is indicated by a dotted line. It is shown. As shown in FIG. 2, the emission peak wavelength of the LED chip 10 is 405 nm, the emission peak wavelength of the green phosphor is 540 nm, the emission peak wavelength of the red phosphor is 640 nm, and the emission peak wavelength of the blue phosphor. Is 475 nm.

  From the black body radiation locus curve of the chromaticity coordinates in the XY chromaticity diagram of the desired correlated color temperature (specifically, 1900K) and the desired duv (specifically, CIE (1931) XYZ color system). The combined light having a deviation duv of −0.02 or more and 0.02 or less (0.0 to −0.0083) is emitted, and a desired excitation light ratio (0 to 130% at 10% intervals). The simulation was carried out so as to obtain () and Ra was measured. Specifically, the emission spectrum of the semiconductor light emitting device 1 in which the emission spectrum intensity of the LED chip 10 and each phosphor is adjusted so that the desired correlated color temperature, the desired deviation duv value, and the desired excitation light ratio are obtained. Ra was obtained by simulation. That is, the semiconductor light emitting device 1 emits combined light having a correlated color temperature of 1900 K and a duv of 0.0 to −0.0083, and the excitation light ratio is 0%, 10%, 20%, 30%, 40%. 50%, 60%, 70%, 80%, 90%, 100%, 110%, 120%, or 130% of the emission spectrum of the semiconductor light emitting device 1 was obtained by simulation, and Ra was measured.

  FIG. 3 is a graph showing a simulation result of the emission spectrum of the semiconductor light emitting device 1 in which samples having different excitation light ratios are used. In FIG. 3, the emission spectrum of the semiconductor light emitting device 1 using the sample with the excitation light ratio of 0% is shown by a thin broken line, and the emission spectrum of the semiconductor light emitting device 1 using the 10% sample is shown by the middle broken line. The emission spectrum of the semiconductor light-emitting device 1 in which 20% of the sample was used is indicated by a thick dotted line, and the emission spectrum of the semiconductor light-emitting device 1 in which 30% of the sample was used is indicated by a middle dotted line. The emission spectrum of the semiconductor light emitting device 1 in which the sample is used is indicated by a thin dotted line, the emission spectrum of the semiconductor light emitting device 1 in which 50% of the sample is used is indicated by a thick two-dot chain line, and 60% of the sample is used. The emission spectrum of the semiconductor light emitting device 1 is indicated by a medium two-dot chain line, the emission spectrum of the semiconductor light emitting device 1 in which 70% of the sample is used is indicated by a thin two-dot chain line, and the semiconductor in which 80% of the sample is used. Light emitting device The emission spectrum of the semiconductor light-emitting device 1 in which the emission spectrum of 1 is indicated by a thick one-dot chain line, the emission spectrum of the semiconductor light-emitting device 1 in which 90% of the sample is used is indicated in the middle-dotted chain line, Is indicated by a thin alternate long and short dash line, the emission spectrum of the semiconductor light emitting device 1 using 110% of the sample is indicated by a thick solid line, and the emission spectrum of the semiconductor light emitting device 1 using the 120% of the sample is indicated by a solid solid line. The emission spectrum of the semiconductor light emitting device 1 using 130% of the sample is indicated by a thin solid line.

  As described above, the percentage of the ratio of the peak intensity of the excitation light to the peak intensity of the fluorescence is the excitation light ratio. As shown in FIG. 3, from the change in the emission spectrum of the wavelength around 640 nm which is the peak intensity of the fluorescence. However, the value of the excitation light ratio greatly changes as the value of the intensity of the emission spectrum having a wavelength near 405 nm (that is, the peak intensity of the excitation light) changes greatly. In other words, in the present embodiment, in the light emitted from the semiconductor light emitting device 1, the excitation light ratio is changed by changing the intensity of the light (excitation light) emitted from the LED chip 10 which is a violet light emitting diode element having an emission peak wavelength of 405 nm. Is changing.

  FIG. 4 is a table showing Ra simulation results according to changes in the excitation light ratio of the sample whose emission spectrum is shown in FIG. FIG. 5 is a graph showing the simulation result of Ra according to the change in the excitation light ratio of the sample whose emission spectrum is shown in FIG. As shown in FIGS. 4 and 5, Ra increases as the excitation light ratio decreases. Specifically, the Ra value when the excitation light ratio is 60% or more is less than 86, but the Ra value when the excitation light ratio is 50% is 86, and the excitation light ratio is 30%. The value of Ra at a certain time is 88, and the value of Ra when the excitation light ratio is 0% is 92. In the semiconductor light emitting device 1 according to the present invention, the value of the average color rendering index Ra is preferably 86 or more, more preferably 88 or more, further preferably 90 or more, and 92 or more. Particularly preferred.

  As shown in FIG. 4, when the excitation light ratio is 0 to 50%, duv can be set to 0.0000 when the correlated color temperature is set to 1900 K. However, the excitation light ratio is 60 to 60%. In the case of 130%, in the combination of the blue phosphor, the green phosphor and the red phosphor used in this study, the duv could not be set to 0.0000 when the correlated color temperature was 1900K. Therefore, when the excitation light ratio is 60 to 130%, Ra is measured by simulation using the semiconductor light emitting device 1 having a minus value of duv and closest to 0.

  The inventors of the present invention have used a plurality of experiments in which the correlated color temperature is about 1900 K and the excitation light ratios are different from each other, using the same phosphors and LED chips 10 as the phosphors of the respective colors used in the above-described simulation. A sample was prepared. Then, for the semiconductor light emitting device 1 in which each of the plurality of created experimental samples is used, the color rendering index including the special color rendering index such as R9 and the correlated color temperature are measured, and the average color rendering index Ra and light emission are measured. Efficiency was calculated respectively.

  FIG. 6 is a table showing the ratios of phosphors and encapsulants of each color in each of these experimental samples having different excitation light ratios. FIG. 7 is a graph showing respective emission spectra of the semiconductor light emitting device 1 in which these experimental samples having different excitation light ratios are used. In FIG. 7, the emission spectrum of the semiconductor light emitting device 1 using a sample with an excitation light ratio of 70% is indicated by a dotted line, and the emission spectrum of the semiconductor light emitting device 1 using a sample of 48% is indicated by a broken line. The emission spectrum of the semiconductor light emitting device 1 using 27% of the sample is indicated by a one-dot chain line, the emission spectrum of the semiconductor light emitting device 1 using 14% of the sample is indicated by a long broken line, and 10% of the sample is indicated. The emission spectrum of the used semiconductor light emitting device 1 is indicated by a long one-dot chain line, the emission spectrum of the semiconductor light emitting device 1 in which 6% of the sample is used is indicated by a long two-dot chain line, and 3% of the sample is used. The emission spectrum of the semiconductor light emitting device 1 is indicated by a short broken line.

  FIG. 8 is a table showing changes in optical characteristics according to changes in the excitation light ratio in the semiconductor light emitting device 1 when each experimental sample shown in FIG. 6 is used. As shown in FIG. 8, the value of Ra increases as the excitation light ratio decreases. The Ra value is 80 when the excitation light ratio is 70%, and the Ra value is 83 when the excitation light ratio is 48%. However, the Ra value is 86 when the excitation light ratio is 27%, the Ra value is 90 when the excitation light ratio is 14%, and the excitation light ratio is 10%. Ra has a value of 92. Furthermore, Ra is 93 when the excitation light ratio is decreased to 6% or 3%.

  Also, R9, which is the special color rendering index for red, and R12, which is the special color rendering index for blue, tend to increase as the excitation light ratio decreases, and both R9 and R12 are candle colors. The light (correlated color temperature in this experimental example) is a high value.

On the other hand, as shown in FIG. 8, the luminous efficiency η _L tends to decrease as the excitation light ratio increases or decreases, peaking when the excitation light ratio is about 48%. Specifically, the luminous efficiency eta _L when the excitation light ratio is 48% whereas a 40.4, luminous efficiency eta _L when the excitation light ratio was increased to 70% in 37.0 is there. That is, when the excitation light ratio increases from 48%, the luminous efficiency η _L decreases. Moreover, the luminous efficiency eta _L is also reduced in accordance with the excitation light ratio is reduced from 48%, the luminous efficiency eta _L when the excitation light ratio is 3% is 37.0. That is, when the excitation light ratio decreases from 48%, the light emission efficiency η _L decreases.

The inventors of the present invention create another experimental sample that emits light having a correlated color temperature of about 1900K using a phosphor different from the red phosphor used in the above-described simulation, and a special color rendering index such as R9. The color rendering index and correlated color temperature were measured, and the average color rendering index Ra and the luminous efficiency were calculated. Specifically, the red phosphor, CASON (CaAlSi (N, O ) 3: Eu) in place, SCASN ((Sr, Ca) AlSi (N, O) 3: Eu) is used. FIG. 9 is a table showing the ratios of phosphors and sealing materials of the respective colors in such other experimental samples. As shown in FIG. 9, the blue phosphor and the green phosphor used in the other experimental samples are the same phosphors as the blue phosphor and the green phosphor in the above-described simulation and the above-described experimental sample, respectively. . The peak wavelength of the LED chip used for the other experimental sample is 409 nm, which is about the same as the peak wavelength of the LED chip 10 used for the simulation and the experimental sample described above. .

FIG. 10 is a table showing optical characteristics of the other experimental samples shown in FIG. As shown in FIG. 10, another experimental sample in which SCASN is used for the red phosphor has an excitation light ratio of 19%, a luminous efficiency η _L of 40.5%, and Ra of 82. As shown in FIG. 10, in another experimental sample in which SCASN is used for the red phosphor, the luminous efficiency η _L is a high value of 40.5% when the excitation light ratio is 19%.

As shown in FIG. 8 and FIG. 10, in both the case where CASON is used as the red phosphor and the case where SCASN is used, the excitation light ratio is within a range of 5% or more and less than 60%. , Ra is a value exceeding 80, and the luminous efficiency η _{L is} a value exceeding 33%. That is, if the excitation light ratio is 5% or more and less than 60%, the Ra value and the light emission efficiency η _L can be made compatible at a high level.

  Considering only the value of Ra, the excitation light ratio is preferably 55% or less, more preferably 50% or less, particularly preferably 45% or less, and further preferably 35% or less. Preferably, it is more preferably 25% or less, and most preferably 15% or less. The lower limit of the excitation light ratio is usually 0%.

  Table 1 is a table showing the results of a sensory test by 13 subjects with respect to light emitted from the semiconductor light emitting device 1 using experimental samples having different excitation light ratios. In Table 1, the ◎ column indicates the number of people who answered, “I felt almost like a candle. I felt like a candle flame”. The ○ column indicates the number of respondents who answered “I did not feel much unnaturalness”. The x column indicates the number of people who answered “I felt blue and felt unnatural”.

  As shown in Table 1, the lower the excitation light ratio, the greater the number of people who responded with 増 え, and the smaller the number of people who answered with x. Therefore, although the coordinate value of the chromaticity point and the correlated color temperature of the light emitted from each semiconductor light emitting device 1 do not change so much, in this sensory test, the light emitted by the experimental sample having a lower excitation light ratio. All subjects determined to be closer to the light emitted by the candle.

However, considering that when the excitation light ratio is reduced to 48% or less, the value of the light emission efficiency η _L also decreases, the excitation light ratio is preferably less than 60% and preferably 5% or more. More preferably, it is more preferably 20% or more.

  Further, it is preferable that the maximum value of the spectrum having a wavelength of 440 nm or more and 480 nm or less is smaller than the maximum peak intensity of light emitted from the LED chip 10. As shown in FIG. 6, in this embodiment, the LED chip 10 having a wavelength of light having a maximum peak intensity of 410 nm is used. As shown in FIG. 7, among the experimental samples of the present embodiment, the wavelength of light emitted by the experimental sample whose excitation light ratio is 5% or more and less than 60% is 440 nm or more and 480 nm or less. The maximum value of the spectrum is smaller than the spectrum near the wavelength of 410 nm, that is, the maximum peak intensity of the light emitted from the LED chip 10. With such a configuration, it is possible to achieve both a large Ra value and high light emission efficiency despite the fact that the light has a relatively low correlated color temperature of less than 2400K.

  According to the present embodiment, by reducing the excitation light ratio (preferably less than 60%), the correlated color temperature is 1600K or more, less than 2400K, preferably less than 2000K, and light with a large Ra value is emitted. Can be emitted. Further, the light emitted from the LED chip 10 can be obtained without complicated adjustment of the mixing ratio of the respective phosphors such as the green phosphor and the red phosphor and selection of the respective phosphors only for the purpose of increasing Ra. By adjusting the ratio between the peak intensity value and the maximum peak intensity of the light emitted from the phosphor 20, the Ra value can be increased.

  When the LED chip 10 having an emission peak wavelength of 420 nm or less is used, the total amount of the phosphor 20 and the phosphor 20 are not changed without greatly changing the blending ratio of the green phosphor, the red phosphor, and the blue phosphor. The excitation light ratio is adjusted by adjusting the ratio of the silicone resin as the sealing material for sealing the inside of the semiconductor light emitting device 1 (that is, the ratio of the phosphor 20 in the silicone resin composition). can do.

  In the simulation and each experimental sample described above, the phosphor 20 is formed by mixing the green phosphor, the red phosphor, the blue phosphor, and the sealing material. However, the phosphor layer 20L in which the green phosphor, the red phosphor, and the blue phosphor are juxtaposed may be formed at a position where the light emitted from the LED chip 10 is received. Such a configuration can prevent cascade excitation caused by mixing phosphors of respective colors.

  FIG. 11 is a schematic diagram showing a configuration of the semiconductor light emitting device 11 in which the phosphor layer 20L is formed. FIG. 11A is a schematic cross-sectional view showing the configuration of the semiconductor light emitting device 11 in which the phosphor layer 20L is formed. FIG. 11B is a schematic perspective view showing the configuration of the semiconductor light emitting device 11 in which the phosphor layer 20L is formed. As shown in FIGS. 11A and 11B, the phosphor layer 20L includes a plurality of green phosphor portions 20g, a red phosphor portion 20r, and a blue phosphor portion 20b. Each phosphor portion is formed on a holding member 20h formed in a film shape or a plate shape so as to have a first surface 21 facing the upper surface 10a of the LED chip 10 placed on the substrate 20k. That is, the phosphor layer 20L includes a holding member 20h in which each phosphor portion is formed on the second surface 22.

  For example, a transparent resin material or a glass material is used for the holding member 20h. As the transparent resin material, for example, a thermoplastic resin, a thermosetting resin, a photocurable resin, or the like is used. However, the transparent resin material has sufficient transparency and durability with respect to light emitted from the LED chip 10. Preferably a material is used.

  Examples of such materials include (meth) acrylic resins such as poly (meth) methyl acrylate, styrene resins such as polystyrene and styrene-acrylonitrile copolymers, polycarbonate resins, polyester resins, phenoxy resins, butyral resins, polyvinyl alcohol, and ethyl cellulose. And cellulose resins such as cellulose acetate and cellulose acetate butyrate, epoxy resins, phenol resins, and silicone resins. In addition, for example, an inorganic material obtained by solidifying a solution obtained by hydrolyzing a solution containing a metal alkoxide, a ceramic precursor polymer, or a metal alkoxide by a sol-gel method, or a combination thereof, for example, In addition, there are inorganic materials and glass having a siloxane bond.

  In the phosphor layer 20L, a partition portion 20s provided at the boundary between the phosphor portions 20r, 20g, and 20b of adjacent colors is formed on the holding member 20h. That is, the plurality of red phosphor portions 2r, the plurality of green phosphor portions 2g, and the plurality of blue phosphor portions 2b are arranged in parallel with the partition portion 20s interposed therebetween.

  In the present embodiment, a partition 20s separates one surface of the holding member 20h facing in the thickness direction (for example, the second surface 22 opposite to the first surface 21 facing the upper surface 10a of the LED chip 10). A plurality of red phosphor portions 20r and a plurality of green phosphor portions 20g are applied to each region by applying phosphor portions 20r, 20g, and 20b of each color mixed with a predetermined filler by screen printing or the like. And a plurality of blue phosphor portions 20b are juxtaposed with the partition portion 20s interposed therebetween. That is, the plurality of red phosphor portions 20r, the plurality of green phosphor portions 20g, and the plurality of blue phosphor portions 20b are arranged on the surface facing the thickness direction of the film-like or plate-like phosphor layer 20L. . Note that phosphor portions 20r, 20g, and 20b of each color mixed with a predetermined filler are applied to the first surface 21 of the holding member 20h by screen printing or the like in each region partitioned by the partition portion. Good. Further, the holding member 20h is partitioned into a plurality of regions by a partition member constituting the partition portion 20s, and a red phosphor portion 2r in which a red phosphor is mixed with a filler and a green color in each region partitioned by the partition member. A green phosphor portion 2g in which a phosphor is mixed with a filler and a blue phosphor portion 2b in which a blue phosphor is mixed with a filler may be formed.

  In the phosphor layer 20L of the present embodiment, the area of each phosphor portion on the second surface 22 of the holding member 20h is determined based on the excitation light ratio. Specifically, for example, the area of each phosphor portion is determined by an area ratio corresponding to the blending ratio of each phosphor corresponding to each excitation light ratio shown in FIG. In addition, the area ratio of each phosphor part may be made different by changing the size of the region for each color of the phosphor part, and each fluorescent light is made by making the number of regions different for each color of the phosphor part. You may vary the area ratio of a body part. Further, the mixing ratio of each phosphor and filler may be made different from each other based on the excitation light ratio.

  Further, between the first surface 21 of the phosphor layer 20L and the upper surface 10a of the LED chip 10, for example, the sealing material 20j is filled with a thickness of 0.1 mm or more and 500 mm or less. The phosphor layer 20L is supported by the holding member 20h so that the distance from the upper surface 10a of the LED chip 10 is 0.1 mm or more and 500 mm or less.

  The partition portion may be made of, for example, a material selected from alumina ceramic, ceramic, resin, glass epoxy, composite resin containing a filler in the resin, and the like. In order to reflect light back into the phosphor portions of each color, a silicone resin containing a white pigment such as alumina powder, silica powder, magnesium oxide, or titanium oxide may be used.

As described above, when the phosphor 20 is formed by mixing the green phosphor, the red phosphor, the blue phosphor, and the sealing material (when phosphors of each color are mixed), the phosphor portion 20r of each color. , 20g, and 20b are formed (when the phosphors of the respective colors are separately applied), but when the phosphors of the respective colors are mixed, a blue phosphor (Sr , Ba, Ca) ₅ (PO ₄ ) ₃ Cl: Eu is preferably used. When the phosphors of the respective colors are separately applied, it is preferable to use (Sr, Ba, Ca) ₅ (PO ₄ ) ₃ Cl: Eu or BaMgAl ₁₀ O ₁₇ : Eu as the blue phosphor.

Here, the reason why (Sr, Ba, Ca) ₅ (PO ₄ ) ₃ Cl: Eu is preferably used even when phosphors of respective colors are mixed will be described. First, when phosphors of respective colors are mixed, cascade excitation occurs in which the blue fluorescence emitted by the blue phosphor is absorbed by the green phosphor and the red phosphor. Further, (Sr, Ba, Ca) ₅ (PO ₄ ) ₃ Cl: Eu has higher emission efficiency of fluorescence using light having a wavelength of about 410 nm as excitation light than that of BaMgAl ₁₀ O ₁₇ : Eu. Then, (Sr, Ba, Ca) ₅ (PO ₄ ) ₃ Cl: Eu is mixed with phosphors of other colors, and the blue color emitted from (Sr, Ba, Ca) ₅ (PO ₄ ) ₃ Cl: Eu is emitted. Even if the fluorescence is absorbed by the phosphors of other colors by the cascade excitation, the blue light having the required intensity is emitted from the semiconductor light emitting device 1. Therefore, it is preferable to use (Sr, Ba, Ca) ₅ (PO ₄ ) ₃ Cl: Eu even when phosphors of respective colors that cause cascade excitation are mixed.

<Reference example>
The experimental results of white semiconductor light emitting devices in which the excitation light ratio is adjusted to a predetermined value, the correlated color temperature is 2700 K, the duv is 0.00, and the excitation light ratios of the emitted light are different are shown below. As the LED chip 10, a 350 μm square InGaN-based violet light-emitting diode element having an emission peak wavelength of about 405 nm and a half width of about 30 nm is used. Note that the emission peak wavelength and the half width are measured using an integrating sphere. Β-sialon is used as the green phosphor, CaAlSi (N, O) ₃ : Eu is used as the red phosphor, and (Sr _1-x Ba _x ) ₅ (PO ₄ ) ₃ Cl: Eu (as the blue phosphor). x> 0) is used. The emission peak wavelength of the green phosphor is 542 nm and the half value width is 56 nm, the emission peak wavelength of the red phosphor is 640 nm and the half value width is 115 nm, and the emission peak wavelength of the blue phosphor is 475 nm and half value. The value width is 80 nm. The emission peak wavelength and half-value width of each phosphor are values measured with a spectrophotometer.

  Each white semiconductor light emitting device is manufactured by mounting six purple light emitting diode elements on a 5050 SMD type alumina ceramic package and sealing with a silicone resin composition to which a powdery phosphor is added. Table 2 shows the content (weight% concentration) of each phosphor in the silicone resin composition for sealing the light emitting diode element used in each white semiconductor light emitting device. For example, the white semiconductor light emitting device of Reference Example 1 includes a blue phosphor, a green phosphor, and a red phosphor at concentrations of 1.5 wt%, 3.7 wt%, and 7.9 wt%, respectively. The purple light emitting diode element is sealed with a silicone resin composition containing a phosphor mixture composed of a phosphor and a red phosphor at a concentration of 13.0 wt%. The white semiconductor light emitting device of Reference Example 2 includes blue phosphor, green phosphor, and red phosphor at concentrations of 5.7 wt%, 3.8 wt%, and 9.9 wt%, respectively. The purple light emitting diode element is sealed with a silicone resin composition containing a phosphor mixture composed of a phosphor and a red phosphor at a concentration of 19.4 wt%. The white semiconductor light-emitting device of Reference Example 3 includes blue phosphor, green phosphor, and red phosphor at concentrations of 16.0 wt%, 3.5 wt%, and 10.5 wt%, respectively. And a purple light-emitting diode element is sealed with a silicone resin composition containing a phosphor mixture composed of red phosphor at a concentration of 30.0 wt%.

  As shown in Table 2, the excitation light ratio of the light emitted by the white semiconductor light emitting device of Reference Example 1 is 175%, and the excitation light ratio of the light emitted by the white semiconductor light emitting device of Reference Example 2 is 79%. The excitation light ratio of the light emitted by the white semiconductor light emitting device of Reference Example 3 is 23%. As apparent from Table 2, it can be seen that, for example, the excitation light ratio can be adjusted by adjusting the content of the phosphor mixture in the silicone resin composition.

  For example, a transparent resin material, a glass material, or the like is used as a silicone resin used as a sealing material for sealing a light emitting diode element of a semiconductor light emitting device. As the transparent resin material, for example, a thermoplastic resin, a thermosetting resin, a photocurable resin, or the like is used. However, sufficient transparency and durability against near-ultraviolet light emitted from the light-emitting diode element are used. It is preferable that the material which it has is used. Examples of such materials include (meth) acrylic resins such as poly (meth) methyl acrylate, styrene resins such as polystyrene and styrene-acrylonitrile copolymers, polycarbonate resins, polyester resins, phenoxy resins, butyral resins, polyvinyl alcohol, and ethyl cellulose. And cellulose resins such as cellulose acetate and cellulose acetate butyrate, epoxy resins, phenol resins, and silicone resins. In addition, for example, an inorganic material obtained by solidifying a solution obtained by hydrolyzing a solution containing a metal alkoxide, a ceramic precursor polymer, or a metal alkoxide by a sol-gel method, or a combination thereof, for example, In addition, there are inorganic materials and glass having a siloxane bond.

  Moreover, the light-scattering agent may be contained in the sealing material. The light scattering agent contained in the sealing material is preferably inorganic particles, such as silica, titanium oxide, and aluminum oxide. When the light scattering agent is included in the sealing material, the total amount of phosphors contained in the sealing material and the blending ratio of each phosphor can be adjusted by adjusting the amount of the light scattering agent contained in the sealing material. The excitation light ratio can be adjusted without greatly changing.

  In the above-described embodiment, the combined color light having a specific color temperature of 1600K or higher and lower than 2400K, preferably lower than 2000K is obtained, but includes a semiconductor light emitting device that emits light having different correlated color temperatures. A semiconductor light emitting system may be configured. FIG. 12 is a schematic explanatory diagram illustrating an example of a semiconductor light emitting system including a semiconductor light emitting device that emits light having different correlated color temperatures. In the example shown in FIG. 12, a semiconductor light emitting device 1a and a semiconductor light emitting device 1b that emit light having different correlated color temperatures are arranged side by side. The semiconductor light emitting device 1a includes an LED chip 10a and a phosphor 20a. The semiconductor light emitting device 1b includes an LED chip 10b and a phosphor 20b.

  The semiconductor light emitting device 1a shown in FIG. 12 has the same configuration as that of the semiconductor light emitting device 1 of the above-described embodiment. For example, the semiconductor light emitting device 1b emits light having a correlated color temperature of 1900K (that is, candle color). For example, light having a correlated color temperature other than 1900K (that is, a color other than the candle color) of 2000K or higher, preferably 2400K or higher and 6700K or lower is emitted. The correlated color temperature difference, which is the difference between the correlated color temperature of the light emitted from the semiconductor light emitting device 1a and the correlated color temperature of the light emitted from the semiconductor light emitting device 1b, is preferably 2000K or more, and preferably 3000K or more. Is more preferable, and 3500K or more is particularly preferable. Specifically, for example, the correlated color temperature of light emitted from the semiconductor light emitting device 1a is 1900K, and the correlated color temperature of light emitted from the semiconductor light emitting device 1b is either 2700K, 5000K, or 6700K. According to such a configuration, for example, by controlling the amount of current flowing through the LED chip in each semiconductor light emitting device, the intensity of light emitted from the semiconductor light emitting device 1a and the intensity of light emitted from the semiconductor light emitting device 1b are adjusted. Then, the correlated color temperature of the combined light obtained by combining the respective lights is the correlated color temperature of the light emitted from the semiconductor light emitting device 1a (for example, 1900K) and the correlated color temperature of the light emitted from the semiconductor light emitting device 1b (for example, 2700K, 5000K or 6700K) can be realized.

  FIG. 13 shows another example of the semiconductor light emitting system having the semiconductor light emitting device 1a and the semiconductor light emitting device 1b as shown in FIG. In the example shown in FIG. 13, the semiconductor light emitting system 101 includes four LEDs mounted in two rows on the chip mounting surface 102 a of the wiring substrate 102 made of an alumina-based ceramic having excellent electrical insulation and good heat dissipation. A chip 103 is provided. Further, on the chip mounting surface 102 a of the wiring substrate 102, an annular and truncated cone-shaped reflector (wall member) 104 is provided so as to surround the LED chips 103.

  In the semiconductor light emitting device 1a, as described above, the average color rendering index Ra is preferably 86 or more, more preferably 88 or more, further preferably 90 or more, and 92 or more. It is particularly preferred. Further, the semiconductor light emitting device 1b also preferably has an average color rendering index Ra of 86 or more, more preferably 88 or more, further preferably 90 or more, and particularly preferably 92 or more. preferable. In particular, by setting the value of the average color rendering index Ra of the semiconductor light emitting device 1a as one of the above preferable values, and setting the value of the average color rendering index Ra of the semiconductor light emitting device 1b as any of the above preferable values, The variation in the average color rendering index Ra when the color temperature is adjusted can be reduced.

  The inside of the reflector 104 is divided into a first region 106 and a second region 107 by a partition member 105, and each region is filled with a phosphor mixed with a filler. Specifically, the first region 106 is filled with, for example, a phosphor for emitting light having a correlated color temperature of 1900 K, as in the semiconductor light emitting device 1 and the semiconductor light emitting device 1a in the above-described embodiment. Similarly to the semiconductor light emitting device 1b described above, the second region 107 is filled with, for example, a phosphor for emitting light having a correlated color temperature of 2700K, 5000K, or 6700K. Therefore, the semiconductor light emitting device 1a is configured in the first region 106 by the LED chip 103 and the phosphor filled in the first region 106, and the LED chip 103 and the second region 107 are formed in the second region 107. Thus, the semiconductor light emitting device 1b is constituted by the phosphor filled. The reflector 104 and the partition member 105 can be formed of resin, metal, ceramic, and the like, and are fixed to the wiring board 102 using an adhesive or the like. Moreover, when using the material which has electroconductivity for the reflector 104 and the partition member 105, the process for giving electrical insulation with respect to a wiring pattern is needed.

  The number of LED chips 103 shown in FIG. 13 is an example, and can be increased or decreased as necessary. One LED chip 103 can be provided for each of the first region 106 and the second region 107, and It is also possible to vary the number in the area. Also, the material of the wiring board 102 is not limited to alumina ceramics, and various materials can be applied, for example, ceramic, resin, glass epoxy, composite resin containing filler in the resin, etc. A selected material may be used. Furthermore, in order to improve the light reflectivity on the chip mounting surface 102a of the wiring substrate 102 and improve the light emission efficiency of the semiconductor light emitting system, a silicone resin containing a white pigment such as alumina powder, silica powder, magnesium oxide, titanium oxide or the like. Is preferably used. On the other hand, it is also possible to improve heat dissipation using a metal substrate such as a copper substrate or an aluminum substrate. However, in this case, it is necessary to form a wiring pattern on the wiring board with electrical insulation therebetween.

  Further, the shapes of the reflector 104 and the partition member 105 described above are examples, and can be variously changed as necessary. For example, instead of the reflector 104 and the partition member 105 formed in advance, a dispenser or the like is used to form an annular wall portion (wall member) corresponding to the reflector 104 on the chip mounting surface 102a of the wiring board 102, and then the partition member 105. A partition wall (partition member) corresponding to may be formed. In this case, examples of the material used for the annular wall portion and the partition wall portion include a paste-like thermosetting resin material or a UV curable resin material, and a silicone resin containing an inorganic filler is preferable.

  According to the configuration shown in FIG. 13, the amount of current flowing through the semiconductor light emitting device 1a and the semiconductor light emitting device 1b is controlled, and the correlated color temperature of light emitted from the semiconductor light emitting device 1a installed in the first region 106 ( For example, the combined light emitted by the semiconductor light emitting system between 1900K) and the correlated color temperature of the light emitted by the semiconductor light emitting device 1b installed in the second region 107 (for example, either 2700K, 5000K or 6700K). The correlated color temperature can be adjusted.

  In the configuration shown in FIG. 13, instead of filling the first region 106 and the second region 107 with the phosphor, the phosphor is applied to a transparent plate and placed above the LED chip 103. Good.

  FIG. 14 is a schematic cross-sectional view illustrating a configuration example of a lighting fixture 200 including the semiconductor light emitting device 1 of the above-described embodiment. In the lighting fixture 200 of the example shown in FIG. 14, the semiconductor light emitting device 1 is installed on the upper surface of the base member 201. And the cover member 202 is installed in the position through which the light emitted from the semiconductor light emitting device 1 passes. In the example shown in FIG. 14, the cover member 202 has an outer shape shaped like a candle flame, and is provided with a recess 203 directed upward on the bottom surface. Then, between the bottom surface of the cover member 202 and the top surface of the base member 201, the cover member 202 is surrounded by the inner wall of the cover member 202 and the top surface of the recess 203, which are generated by providing the recess 203. The semiconductor light emitting device 1 is installed in the part.

  The LED chip 10 is supplied with power for emitting light by the electric wire 204. Then, the LED chip 10 emits light, and the phosphor 20 emits fluorescence when excited by the light emitted by the LED chip 10. The semiconductor light emitting device 1 including the LED chip 10 and the phosphor 20 radiates candle light, which is a combined light of the light emitted from the LED chip 10 and fluorescence, to the outside through the cover unit 202.

  According to such a configuration, the candle-colored light emitted from the semiconductor light-emitting device 1 passes through the cover member 202 and is emitted to the outside, so that the lighting fixture 200 emits the candle-colored light and the candle flame. It is possible to make it appear as if the cover member 202 having an outer shape of the above is emitting candle light. Therefore, the lighting apparatus 200 can be put into a lighting state that is in the shape of a candle flame.

  14 illustrates that the semiconductor light emitting device 1 including the phosphor 20 in which the phosphors of the respective colors are mixed is illustrated, but the phosphors of the respective colors as illustrated in FIG. 11 are separately applied. Then, the semiconductor light emitting device 11 in which the phosphor layer 20L is formed may be installed.

1, 1a, 1b, 11 Semiconductor light emitting device 10, 10a, 10b, 103 LED chip 20, 20a, 20b Phosphor 20r Red phosphor 20g Green phosphor 20b Blue phosphor 20L Phosphor layer 20k Substrate 20h Holding member 20s Partition 20j Sealing material 101 Semiconductor light emitting system 102 Wiring board 102a Chip mounting surface 104 Reflector 105 Partition member 106 First region 107 Second region 200 Lighting fixture 201 Base member 202 Cover member 203 Concave portion 204 Electric wire

Claims (14)

A semiconductor light emitting device that emits light having an emission peak of 380 nm or more and 430 nm or less;
A phosphor that emits light using the semiconductor light emitting element as an excitation source,
In a lighting fixture including a semiconductor light emitting device that emits light having a correlated color temperature of 1600K or higher and lower than 2400K,
The phosphor includes at least a blue phosphor, a green phosphor and a red phosphor,
In the spectrum of light emitted from the semiconductor light emitting device, the value of the peak intensity of light emitted by the semiconductor light emitting element is less than 60% of the maximum peak intensity of light emitted by the phosphor, and The maximum peak of the light emitted from the phosphor is located at 600 nm or more and 660 nm or less,
An illuminating device, wherein a cover member having an outer shape simulating the shape of a candle flame is installed at a position where light emitted from the semiconductor light emitting device passes. The light having a spectrum such that the peak intensity value of the light emitted by the semiconductor light emitting element is not less than 5% of the maximum peak intensity of the light emitted by the phosphor is emitted. The lighting fixture as described in. The lighting apparatus according to claim 1, wherein the light having the correlated color temperature of 1600 K or more and less than 2000 K is emitted. The luminaire according to any one of claims 1 to 3, wherein the blue phosphor has a half-value width of an emission peak wavelength of 30 nm or more. 5. The lighting apparatus according to claim 1, wherein the blue phosphor is (Sr, Ba, Ca) ₅ (PO ₄ ) ₃ Cl: Eu, or BaMgAl ₁₀ O ₁₇ : Eu. . In the XY chromaticity diagram of the CIE (1931) XYZ color system, the chromaticity coordinates of the light emitted from the semiconductor light emitting device have a deviation duv from the black body radiation locus curve of −0.02 or more and 0. It is below 02. The lighting fixture in any one of the Claims 1 thru | or 5 characterized by the above-mentioned. The green phosphor is β sialon, (Ba, Sr) ₃ Si ₆ O ₁₂ N ₂ : Eu, or (Sr, Ba) ₂ SiO ₄ : Eu. The lighting fixture as described in. The red phosphor includes (CaAlSiN ₃ ) _1-x (Si ₂ N ₂ O) _x : Eu (x is 0 <x <0.5). The luminaire described. The lighting apparatus according to any one of claims 1 to 8, wherein the red phosphor contains K ₂ SiF ₆ : Mn. The red _{phosphor, A 2 + x M y Mn} Z F n (A is one or both Na and K Tonouchi .M is Si and Al. Then, -1 ≦ x ≦ 1, and 0 .9 ≦ y + z ≦ 1.1, 0.001 ≦ z ≦ 0.4, and 5 ≦ n ≦ 7)
The lighting fixture according to any one of claims 1 to 8, wherein: The illumination according to any one of claims 1 to 10, wherein the phosphor transmits light emitted by the semiconductor light emitting element with a predetermined transmittance and emits the light to the outside of the semiconductor light emitting device. Instruments. A holding member for holding the phosphor;
The holding member holds the phosphor of each color in a predetermined region set for each color, and forms a phosphor layer provided with a region for holding the phosphor for each color;
The illumination according to any one of claims 1 to 11, wherein the phosphor layer is supported such that a distance between the phosphor layer and the semiconductor light emitting element is 0.1 mm or more and 500 mm or less. Instruments. The first semiconductor light emitting device comprises the semiconductor light emitting device according to any one of claims 1 to 12,
A lighting apparatus comprising: a semiconductor light emitting device that emits light having a correlated color temperature different from that of light emitted from the first semiconductor light emitting device as the second semiconductor light emitting device. The average color rendering index Ra of the first semiconductor light emitting device is 86 or more, and the average color rendering index Ra of the second semiconductor light emitting device is 86 or more. 13. The lighting fixture according to 13.

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