JP6354607B2 - Light emitting device - Google Patents

Description

  The present invention relates to a light emitting device.

  In recent years, instead of incandescent bulbs, light-emitting diodes (Light Emitting Diodes: hereinafter also referred to as “LEDs”) excellent in energy saving have been widely used as light-emitting elements. For example, a white light emitting device combining a blue light emitting element using gallium nitride and a yellow light emitting phosphor is known. This white light emitting device is mainly used as general illumination. A white light emitting device in the field of general lighting is desired to have high color rendering properties. Therefore, a green phosphor and a red phosphor are combined with a white light emitting device.

  However, it is desired that the lighting of meat display shelves in supermarkets and the like be more vivid reddish than the actual color rendering. Therefore, there is known a lighting fixture that can irradiate light suitable for making a product appear clear by using an optical filter that reduces transmission of light of a predetermined wavelength in a light emitting device that emits white light (for example, (See Patent Documents 1 and 2). Moreover, it has the 1st fluorescent substance which is excited by blue light and converts into the light which has a peak wavelength in 630nm-680nm so that the yellow light component contained in illumination light may be reduced and the appearance of red may be emphasized A light-emitting device including a first light-emitting element and a second light-emitting element having a second phosphor that is excited by blue light and converted into light having a peak wavelength of 500 nm to 550 nm is known ( For example, see Patent Document 3). These light emitting devices can make the meat appear more reddish.

JP 2008-311532 A JP 2012-109397 A Japanese Patent No. 2012-204413

  However, in the conventional light emitting device, the adjustment of the component ratio of each wavelength is still insufficient, and further improvement in appearance has been desired.

  Therefore, the present invention is to provide a light-emitting device that makes the redness more vivid.

  A light-emitting device according to an embodiment of the present invention includes a light-emitting element and two or more kinds of phosphors that emit fluorescence when excited by light from the light-emitting element, and color mixture of the light-emitting element and the phosphor In the emission spectrum of light, the light emission of the light emitting element is a first peak, 500 nm to 600 nm is a second peak, 600 nm to 780 nm is a third peak, and the emission intensity of the first peak is 1. The emission intensity of the second peak is 0.5 to 0.6, the emission intensity of the third peak is 0.6 to 1.0, and the first peak and the second peak The minimum intensity between the peaks is 0.1 to 0.3, and the minimum intensity between the second peak and the third peak is 0.1 to 0.3.

  The light-emitting device of the embodiment according to the present invention can provide a light-emitting device that makes the redness appear more vividly.

It is a schematic plan view which shows the light-emitting device which concerns on embodiment. It is a schematic cross section in the II-II line of the light-emitting device which concerns on embodiment. It is a figure which shows the emission spectrum of four types of fluorescent substance. 6 is a diagram showing emission spectra of light emitting devices according to Examples 1 to 4 and Comparative Example 1. FIG.

  Hereinafter, embodiments will be described with reference to the drawings. However, the embodiment described below is an example for embodying the technical idea of the present invention, and the present invention is not limited to the following. Further, the present specification by no means specifies the members shown in the claims to the members of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention unless otherwise specified, and are merely explanations. It is just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.

  The relationship between the color name and chromaticity coordinates, the relationship between the wavelength range of light and the color name of monochromatic light, and the like comply with JIS Z8110. Specifically, 380 nm to 455 nm is blue purple, 455 nm to 485 nm is blue, 485 nm to 495 nm is blue green, 495 nm to 548 nm is green, 548 nm to 573 nm is yellow green, 573 nm to 584 nm is yellow, 584 nm to 610 nm is yellow red , 610 nm to 780 nm is red.

  FIG. 1 is a schematic plan view showing a light emitting device according to an embodiment. FIG. 2 is a schematic cross-sectional view taken along line II-II of the light emitting device according to the embodiment. The light-emitting device according to the embodiment is an example of a surface-mounted light-emitting device.

  The light-emitting device includes a light-emitting element, a molded body on which the light-emitting element is disposed, and a sealing member that covers the light-emitting element. The sealing member contains a phosphor that emits fluorescence when excited by light from the light emitting element, and optionally a diffusing material. The diffusing material scatters mixed color light from the light emitting element and the phosphor to diffuse the light.

  Note that there are various types of light emitting devices on which light emitting elements are mounted, such as a shell type and a surface mount type. The bullet-type light emitting device here includes a light emitting element disposed on a lead serving as an external connection electrode, and includes a lead and a sealing member that covers the light emitting element. A light-emitting device formed into a shape. The surface-mounted light emitting device refers to a light emitting device formed by arranging a light emitting element and a sealing member covering the light emitting element on a molded body provided with a lead electrode. Further, there is a light emitting device in which a light emitting element is mounted on a flat mounting substrate and a sealing member containing a phosphor is formed in a lens shape or the like so as to cover the light emitting element.

  The light emitting device 100 includes a gallium nitride compound semiconductor light emitting element 10 that emits light having a short wavelength side of visible light, and a molded body 40 that forms a recess on which the light emitting element 10 is placed. The molded body 40 has a first lead 20 and a second lead 30 that are partially exposed on the bottom surface of the recess, and is integrally formed of a thermoplastic resin or a thermosetting resin. A recess having a bottom surface and a side surface is formed in the molded body 40, and the light emitting element 10 is placed on the bottom surface of the recess. The light emitting element 10 has a pair of positive and negative electrodes, and the pair of positive and negative electrodes are electrically connected to the first lead 20 and the second lead 30 via the wire 60. The light emitting element 10 is sealed with a sealing member 50. The sealing member 50 includes a first phosphor 70 that converts the wavelength of light from the light emitting element 10 and a second phosphor 80. The sealing member 50 may contain a diffusing material.

In the emission spectrum of the mixed color light of the light emitting element 10, the first phosphor 70, and the second phosphor 80, the light emission of the light emitting element 10 is the first peak, 500 nm to 600 nm is the second peak, and 600 nm to 780 nm is the first peak. 3 and the first peak emission intensity is 1, the second peak emission intensity is 0.4 to 0.7, and the third peak emission intensity is 0.8 to 1. 2, the minimum intensity between the first peak and the second peak is 0.1 to 0.3, and the minimum intensity between the second peak and the third peak is 0.1 to 0.3. is there.
In the light emitting device, the correlated color temperature of the mixed color is preferably 4000 K to 6000 K, and the deviation (Duv) of the correlated color temperature is preferably −0.03 to −0.02. The correlated color temperature of the mixed color is particularly preferably 4500K to 5500K.

The chromaticity is preferably x = 0.320 to 0.350 and y = 0.280 to 0.340.
In the emission spectrum, when the emission intensity of the first peak is 1, the emission intensity of the second peak is 0.45 to 0.55, the emission intensity of the third peak is 0.90 to 1.04, The minimum intensity between the first peak and the second peak is 0.19 to 0.21, the minimum intensity between the second peak and the third peak is 0.10 to 0.17, and Duv is −0.030. It is especially preferable to set it to -0.015.
The first peak is particularly preferably 440 nm to 470 nm, the second peak is 510 nm to 530 nm, and the third peak is preferably 650 nm to 670 nm.
Conventional light-emitting devices increase only the red component's emission peak in order to increase the red component that is lacking, but the white color of meat fat and the white color of trays other than meat are also colored red. ing. On the other hand, in the light emitting device of the present embodiment, when the correlated color temperature is 4000K to 6000K, and preferably the correlated color temperature is 4500K to 5500K, the meat whiteness of the meat and the white color of the tray other than the meat appear white. Color temperature is adopted. In addition, there is an effect of relatively enhancing the redness of the white and reddish components more than numbers, and the contrast between white and red can be enhanced. The light emitting device of the present embodiment emphasizes red as red and white as white.
Hereinafter, each component will be described.
(Light emitting element 10)

The light emitting element 10 can emit light from the ultraviolet region to the visible light region. The peak wavelength of light emitted from the light emitting element 10 is preferably 240 nm to 520 nm, and more preferably 440 nm to 470 nm. For example, a nitride semiconductor element (In _X Al _Y Ga _1- XYN, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) can be used for the light emitting element 10.

  The light emitting element 10 has a semiconductor layer formed by sequentially laminating an n-type layer, an active layer, and a p-type layer made of a nitride semiconductor on a sapphire substrate. An n-pad electrode is formed on n-type semiconductors that are separated from each other and exposed on the line, while a p-pad electrode is formed on the p-ohmic electrode. Furthermore, the light emitting element 10 preferably has an active layer that has an emission peak wavelength particularly in the vicinity of 240 nm to 520 nm and can emit light having an emission wavelength capable of efficiently exciting the fluorescent material.

The light emitting element 10 emits light having an emission peak wavelength in the short wavelength range from near ultraviolet to visible light, and the first phosphor 70 and the second phosphor 80 are excited by the light from the light emitting element 10. Shows a predetermined emission color. In addition, since the light emitting element 10 can narrow the emission spectrum width, the phosphor can be excited efficiently.
(First phosphor 70, second phosphor 80)

  As the two or more kinds of phosphors, at least a first phosphor 70 and a second phosphor 80 are included. The first phosphor 70 and the second phosphor 80 are excited by the light from the light emitting element 10 to emit fluorescence. Here, the first phosphor 70 has an emission peak at 500 nm to 600 nm, and the second phosphor 80 has an emission peak at 600 nm to 780 nm. In particular, it is preferable that the first phosphor 70 has an emission peak at 510 nm to 550 nm, and the second phosphor 80 has an emission peak at 630 nm to 670 nm. Moreover, the fluorescent substance of each wavelength does not need to be a single substance, and a plurality of fluorescent substances can be combined.

  The first phosphor 70 and the second phosphor 80 are blended so as to be unevenly distributed in the sealing member 50. At this time, the sealing member 50 not only serves as a member for protecting the light-emitting element 10, the first phosphor 70, and the second phosphor 80 from the external environment, but also absorbs a part of the light from the light-emitting element and has a wavelength. It also functions as a wavelength conversion member that converts. Thus, by placing the first phosphor 70 and the second phosphor 80 close to the light emitting element 10, the light from the light emitting element 10 can be efficiently wavelength-converted, and light emission with excellent light emission efficiency. Can with equipment. In addition, arrangement | positioning with the sealing member 50 containing the 1st fluorescent substance 70 and the 2nd fluorescent substance 80, and the light emitting element 10 is not limited to the form which arranges them closely, The influence of the heat | fever to a fluorescent substance In consideration of the above, the light emitting element 10, the first phosphor 70, and the second phosphor 80 may be arranged with a space therebetween. Further, by mixing the first phosphor 70 and the second phosphor 80 so as to be distributed substantially uniformly in the sealing member 50, it is also possible to obtain light without uneven color.

Here, as the first phosphor 70, Ca ₈ MgSi ₄ O ₁₆ Cl _2-δ : Eu (δ is 0 ≦ z ≦ 1) or (Ba, Sr, Ca, Mg) ₂ SiO ₄ : Eu, _{Si 6-z Al z O z} N 8-Z: Eu (Z is 0 <z <4.2), ( Sr, Ca, Ba) Si 2 O 2 N 2: Eu, Ba 3 Si 6 O 12 One or more phosphors represented by N ₂ : Eu, SrGa ₂ S ₄ : E, or phosphors partially substituted with these elements are used. The parentheses indicate that any element is included.

Further, as the second phosphor 80, CaAlSiN ₃ : Eu, (Ca, Sr) AlSiN ₃ : Eu, (Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu, Sr ₂ (Al, Si) ₁₀ (O , N) ₁₄ : Eu, (Sr, Ca) LiAl ₃ N ₄ : Eu, (Ca, Sr, Ba) S: Eu, 3.5MgO · 0.5MgF ₂ · GeO ₂ : Mn, K ₂ (Si, Ti , Ge) F ₆ : Mn or one or more phosphors partially substituted with these elements is used. The parentheses indicate that any element is included.

Furthermore, (Y, Lu) ₃ (Al, Ga) ₅ O ₁₂ : Ce, (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce, which are phosphors emitting blue-green to yellow-red fluorescence ( La, Y) ₃ Si ₆ N ₁₁ : Ce, (La, Ca) ₃ (Si, Al) ₆ (O, N) ₁₁ : Ce, CaSc ₂ O ₄ : Ce, Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce SrAl ₂ O ₄ : Eu, Sr ₄ Al ₁₄ O ₂₅ : Eu, (Ca, Sr, Ba) ₃ Si ₆ O ₉ N ₄ : Eu, Sr ₃ Si ₁₃ Al ₃ O ₂ N ₂₁ : Eu, (Ca, _{Sr) m / 2 Si 12-} mn Al m + n O n n 16-n: Eu, (Sr, Ca) AlSiN 3: Ce, (Sr, Ca, Ba) 3 SiO 5: Eu also emitting aim of such A small amount can be added as long as it falls within the spectrum.

The average particle diameter of the phosphor is preferably 1 μm or more and 50 μm or less in consideration of optical characteristics and workability when manufacturing a light emitting device. Further, the average particle diameter of the diffusing material is more preferably 2 μm or more and 30 μm or less.
(Sealing member 50)

  The sealing member 50 is formed by being filled with a translucent resin or glass so as to cover the light emitting element 10 placed in the recess of the light emitting device 100. In consideration of ease of manufacture, the material of the sealing member 50 is preferably a translucent resin. The translucent resin is preferably a silicone resin composition in consideration of light resistance, but an insulating resin composition such as an epoxy resin composition or an acrylic resin composition can also be used. Moreover, although the 1st fluorescent substance 70 and the 2nd fluorescent substance 80 contain in the sealing member 50, another material can also be added suitably. For example, the sealing member 50 can contain a diffusing material, a light shielding member, an ultraviolet absorbing member, a pigment, and the like. Further, by including two or more kinds of diffusing materials in the sealing member 50, the directivity from the light emitting element 10 can be relaxed and the viewing angle can be increased. Examples of another diffusing material include particles made of silica, alumina, titania, yttria, zirconia, or the like.

The light emitting devices of Examples 1 to 4 will be described. FIG. 3 is a diagram showing emission spectra of four types of phosphors. 4 is a diagram showing emission spectra of the light emitting devices according to Examples 1 to 4 and Comparative Example 1. FIG.
The light-emitting devices of Examples 1 to 4 use a gallium nitride light-emitting element 10 having a light emission peak near 450 nm. As the first phosphor 70 of Examples 1 to 4, chlorosilicate A having an emission peak in the vicinity of 516 nm is used, and the composition of chlorosilicate A is Ca ₈ MgSi ₄ O ₁₆ Cl _{2 -δ} : Eu. The second phosphor 80 of Examples 1 to 4 is a nitride phosphor A having an emission peak near 663 nm, and the composition of the nitride phosphor A is CaAlSiN ₃ : Eu.
The light emitting device of Comparative Example 1 also uses the gallium nitride light emitting element 10 having an emission peak near 450 nm. As the first phosphor of Comparative Example 1, chlorosilicate B having an emission peak in the vicinity of 522 nm is used, and the composition of chlorosilicate B is Ca ₈ MgSi ₄ O ₁₆ Cl _2-δ : Eu. The second phosphor of Comparative Example 1 is a nitride phosphor B having an emission peak near 646 nm, and the composition of the nitride phosphor B is CaAlSiN ₃ : Eu.

Tables 1 and 2 show the measurement results of the light emitting devices of Examples 1 to 4 and Comparative Example 1.
In Table 1, xy represents the chromaticity, Tcp represents the color temperature, Duv represents the deviation from the black body radiation, and the appearance represents the content that is sensibly determined when the meat is actually viewed visually. Although Examples and Comparative Examples have nearly similar chromaticities, Duv is small in Examples 3 and 4.
Table 2 shows the wavelengths of the first peak of 440 to 470 nm, the second peak of 500 to 600 nm, and the third peak of 600 to 780 nm obtained from the emission spectra of Examples 1 to 4 and Comparative Example 1. The emission intensity of each peak when the intensity of the first peak is 1, and the minimum intensity between the emission intensity are shown.

In the emission spectrum of Example 1, when the first peak is 1, the second peak is 0.67, the third peak is 1.13, and the minimum intensity between the first peak and the second peak Is 0.28, and the minimum intensity between the second peak and the third peak is 0.28.
In the emission spectrum of Example 2, when the first peak is 1, the second peak is 0.59, the third peak is 1.13, and the minimum intensity between the first peak and the second peak Is 0.28, and the minimum intensity between the second peak and the third peak is 0.21.
In the emission spectrum of Example 3, when the first peak is 1, the second peak is 0.53, the third peak is 1.02, and the minimum intensity between the first peak and the second peak Is 0.21, and the minimum intensity between the second peak and the third peak is 0.17.
In the emission spectrum of Example 4, when the first peak is 1, the second peak is 0.48, the third peak is 0.94, and the minimum intensity between the first peak and the second peak Is 0.20, and the minimum intensity between the second peak and the third peak is 0.15.
As in Examples 3 and 4, in the emission spectrum, when the first peak is 1, the second peak is 0.45 to 0.55, the third peak is 0.90 to 1.04, The minimum intensity between the first peak and the second peak is 0.19 to 0.21, the minimum intensity between the second peak and the third peak is 0.10 to 0.17, and Duv is −0.030. It is preferable to set it to -0.015.

  In comparison with Comparative Example 1, Examples 1 to 4 are obtained by changing the wavelength of the phosphor. Examples 1 to 4 have improved appearance, and Example 3 has good appearance, particularly Example 4 has good appearance. Was very good. In Examples 3 and 4, the Duv is lowered, but the appearance is good.

  As a factor that improves the appearance in Examples 1 to 4, especially Examples 3 and 4, the blue, green, and red components are set to specific wavelength ranges, and further, by suppressing the components that are valleys of the respective components, intermediate colors It is thought that the red color of the meat looks good because the orange color is suppressed. Also, Duv is set lower than black body radiation. In other words, it is adjusted so that the reddish color is increased as compared with the normal color, and it is considered that the meat looks better.

  Although the light-emitting device of this Embodiment can be used as illumination for meat, it can also be used as surgical illumination and general illumination.

DESCRIPTION OF SYMBOLS 10 Light emitting element 20 1st lead 30 2nd lead 40 Molding body 50 Sealing member 60 Wire 70 1st fluorescent substance 80 2nd fluorescent substance

Claims (7)

A light emitting element;
Two or more kinds of phosphors that emit fluorescence when excited by light from the light-emitting element,
In the emission spectrum of the mixed color light of the light emitting element and the phosphor, the light emission of the light emitting element is a first peak, 500 nm to 600 nm is a second peak, 600 nm to 780 nm is a third peak, When the emission intensity of the first peak is 1, the emission intensity of the second peak is 0.4 to 0.7, the emission intensity of the third peak is 0.8 to 1.2, The minimum intensity between the first peak and the second peak is 0.1 to 0.3, and the minimum intensity between the second peak and the third peak is 0.1 to 0.3. A light emitting device.   The light emitting device according to claim 1, wherein the first peak is in a range of 440 nm to 470 nm.   The light emitting device according to claim 1, wherein the second peak is in a range of 510 nm to 530 nm.   The light emitting device according to any one of claims 1 to 3, wherein the third peak is in a range of 650 nm to 670 nm. At least one of the two or more kinds of phosphors is Ca ₈ MgSi ₄ O ₁₆ Cl _2-δ : Eu (δ is 0 ≦ z ≦ 1) or (Ba, Sr, Ca, Mg) ₂ SiO _4. : Eu, Si _6-z Al _z O _z N _8-Z : Eu (Z is 0 <z <4.2), (Sr, Ca, Ba) Si ₂ O ₂ N ₂ : Eu, Ba ₃ Si 5. The light-emitting device according to claim 1, which is a phosphor represented by ₆ O ₁₂ N ₂ : Eu, SrGa ₂ S ₄ : Eu, or a phosphor obtained by substituting a part of these elements. . At least one of the two or more types of phosphors is CaAlSiN ₃ : Eu, (Ca, Sr) AlSiN ₃ : Eu, (Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu, Sr ₂ (Al, Si) ₁₀ (O, N) ₁₄ : Eu, (Sr, Ca) LiAl ₃ N ₄ : Eu, (Ca, Sr, Ba) S: Eu, 3.5MgO · 0.5MgF ₂ · GeO ₂ : Mn, K ₂ (Si , Ti, Ge) F ₆ : Mn is a phosphor represented by Mn, or a phosphor obtained by substituting part of these elements. _6. The light emitting device according to claim 1.   7. The light emitting device according to claim 1, wherein the correlated color temperature of the mixed color is 4000 K to 6000 K, and the deviation (Duv) of the correlated color temperature is −0.03 to −0.02. 8. Light-emitting device.

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