Light-emitting device and lighting device

Abstract

To improve color rendering while reducing the growth of blue-green algae.SOLUTION: A light-emitting device emits first light having a first emission spectrum with a first peak with light intensity in the wavelength region of 430 nm to 500 nm, a second peak with light intensity in the wavelength region of 500 nm to 565 nm, and a third peak with light intensity in the wavelength region of 620 nm to 750 nm. The first light-emitting spectrum has a first minimum value of light intensity in the wavelength region from 565 nm to 620 nm, which value is less than or equal to half of the light intensity of the second peak and the third peak, respectively. In the first light-emitting spectrum, when the maximum light intensity among the first peak, the second peak, and the third peak is set to 1, the light intensity of each of the first peak, the second peak, and the third peak is 0.6 or higher.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a light-emitting device and a lighting device.

Background Art

[0002] There are light-emitting devices and lighting devices that use light-emitting diodes (LEDs) and the like to enhance color rendering (see, for example, Patent Documents 1 to 3). In addition, there are light-emitting devices and lighting devices that use LEDs and the like to emit light approximating the spectrum of sunlight (also referred to as spectral distribution) as light suitable for breeding organisms and growing plants (see, for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] Regarding light-emitting devices and lighting devices, there is room for improvement in reducing the growth of cyanobacteria while enhancing color rendering.

Means for Solving the Problems

[0005] A light-emitting device and a lighting device are disclosed.

[0006] One aspect of the light-emitting device emits first light of a first emission spectrum having a first peak in the light intensity in the wavelength range of 430 nm to 500 nm, a second peak in the light intensity in the wavelength range of 500 nm to 565 nm, and a third peak in the light intensity in the wavelength range of 620 nm to 750 nm. The first emission spectrum has a first minimum value of light intensity that is less than or equal to half of the light intensity of each of the second peak and the third peak in the wavelength range of 565 nm to 620 nm. In the first emission spectrum, when the maximum light intensity among the first peak, the second peak, and the third peak is set to 1, the light intensity of each of the first peak, the second peak, and the third peak is 0.6 or more.

[0007] One aspect of the lighting device includes a plurality of the light-emitting devices of the above aspect.

[0008] One aspect of the lighting device emits third light of a second emission spectrum having a fifth peak in the light intensity in the wavelength range of 430 nm to 500 nm, a sixth peak in the light intensity in the wavelength range of 500 nm to 565 nm, and a seventh peak in the light intensity in the wavelength range of 620 nm to 750 nm. The second emission spectrum has a second minimum value of light intensity that is less than or equal to half of the light intensity of each of the sixth peak and the seventh peak in the wavelength range of 565 nm to 620 nm. In the second emission spectrum, when the maximum light intensity among the fifth peak, the sixth peak, and the seventh peak is set to 1, the light intensity of each of the fifth peak, the sixth peak, and the seventh peak is 0.6 or more.

Advantages of the Invention

[0009] It is possible to reduce the growth of cyanobacteria while enhancing the color rendering property.

Brief Description of the Drawings

[0010]

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DETAILED DESCRIPTION OF THE INVENTION

[0011] There are light-emitting devices and lighting devices with improved color rendering using light-emitting diodes (LEDs) and the like. In addition, as light suitable for raising organisms and growing plants, there are light-emitting devices and lighting devices that emit light approximating the spectrum (spectral distribution) of sunlight using LEDs and the like.

[0012] Regarding the light source of the lighting device that illuminates large aquariums in an aquarium, from the perspective of energy conservation, it can be replaced from a metal halide lamp to a light source using LEDs. Also, regarding the light source of the lighting device that illuminates small aquariums for household use, etc., from the perspective of energy conservation, a light source using LEDs can be adopted. That is, a light-emitting device and a lighting device using LEDs and the like can be applied to light-emitting devices and lighting devices that illuminate various aquariums ranging from large aquariums to small aquariums.

[0013] By the way, in an aquarium, unnecessary algae such as blue-green algae (also called cyanobacteria) may block the illumination light. This unnecessary algae hinders the irradiation of light to the aquatic organisms in the aquarium and the appreciation of the aquatic organisms in the aquarium. Therefore, the growth of unnecessary algae leads to an increase in the labor required for cleaning the aquarium.

[0014] Therefore, there is room for improvement in the light-emitting device and the lighting device in terms of enhancing the color rendering property while reducing the growth of blue-green algae.

[0015] Therefore, the inventors of the present disclosure have created a technique capable of enhancing the color rendering property while reducing the growth of blue-green algae for the light-emitting device and the lighting device.

[0016] Regarding this, various embodiments and various examples will be described below with reference to the drawings. In the drawings, the same reference numerals are given to parts having the same or similar configurations and functions. Duplicate descriptions are omitted in the following description. The drawings are schematically shown.

[0017] <1. Configuration of the light-emitting device> FIG. 1 is a schematic view showing an example of the appearance of a light-emitting device 1 according to an embodiment. FIG. 2 is a schematic view showing a virtual cross-section along a virtual plane Vp1 drawn by a thin two-dot chain line in FIG. 1 of an example of the light-emitting device 1 according to an embodiment. FIG. 3 is a schematic view showing an enlarged view of a circular region III surrounded by a thin one-dot chain line in the virtual cross-section of FIG. 2.

[0018] The light-emitting device 1 is a device that emits light (also referred to as first light) toward the outside of the light-emitting device 1. As shown in FIGS. 1 to 3, the light-emitting device 1 includes, for example, a substrate 2, a light-emitting element 3, a frame body 4, a sealing member 5, and a wavelength conversion member 6.

[0019] The substrate 2 is a substrate on which the light-emitting element 3 is mounted. The substrate 2 includes, for example, an insulating base material. The material of the base material may be, for example, a ceramic such as alumina or mullite, or a glass ceramic. The material of the base material may be, for example, a material in which a plurality of types of ceramics are mixed, or a composite material such as a material in which a ceramic and a glass ceramic are mixed. The material of the base material may be, for example, a polymer resin in which fine particles of a metal oxide are dispersed. In this case, the thermal expansion coefficient of the substrate 2 can be appropriately adjusted.

[0020] The substrate 2 has a first surface 2a. This first surface 2a may be referred to as the upper surface of the substrate 2. The substrate 2 has, for example, a surface on the opposite side of the first surface 2a (also referred to as the lower surface). The substrate 2 has, for example, a conductor (also referred to as a wiring conductor) that electrically connects the inside and the outside of the substrate 2 on the first surface (upper surface) 2a, inside the substrate 2, and the lower surface. The material of the wiring conductor may be, for example, a conductive material such as tungsten, molybdenum, manganese, or copper. When the material of the base material of the substrate 2 is a ceramic, the substrate 2 having the wiring conductor can be produced, for example, by laminating and firing a ceramic green sheet on which a metal paste is printed in a predetermined pattern. The metal paste can be produced, for example, by adding an organic solvent to a powder of a conductive material such as tungsten. A plating layer such as nickel or gold may be formed on the surface of the wiring conductor, for example, to reduce oxidation. A reflective layer may be formed on the first surface 2a of the substrate 2 at a position away from the wiring conductor and the plating layer. Thereby, the reflective layer can efficiently reflect the light emitted by the light-emitting element 3 in the direction in which the first surface 2a faces from the substrate 2. As the material of the reflective layer, for example, aluminum, silver, gold, copper, or platinum is applied.

[0021] The light-emitting element 3 is, for example, in a state of being mounted on the first surface 2a of the substrate 2. The light-emitting element 3 may be in a state of being electrically connected via a brazing material or solder, for example, on a gold plating layer adhered to the surface of a wiring conductor on the first surface 2a of the substrate 2. For the light-emitting element 3, for example, a light-emitting diode (LED) capable of emitting light outward in response to recombination of electrons and holes in a pn junction region using a semiconductor is applied. For example, the light-emitting element 3 has a translucent substrate and a light semiconductor layer located on the translucent substrate. For the translucent substrate, a substrate capable of growing a light semiconductor layer using a chemical vapor deposition method such as a metalorganic chemical vapor deposition method or a molecular beam epitaxial growth method is applied. Examples of the material of the translucent substrate include sapphire, gallium nitride, aluminum nitride, zinc oxide, zinc selenide, silicon carbide, silicon, or zirconium diboride. The thickness of the translucent substrate may be, for example, from 50 micrometers (μm) to 1000 μm.

[0022] The optical semiconductor layer has, for example, a first semiconductor layer, a light-emitting layer, and a second semiconductor layer. The first semiconductor layer may be located on a translucent substrate. The light-emitting layer may be located on the first semiconductor layer. The second semiconductor layer may be located on the light-emitting layer. The materials of the first semiconductor layer, the light-emitting layer, and the second semiconductor layer may be, for example, group-III nitride semiconductors or III-V semiconductors. The group-III nitride semiconductor may be, for example, gallium nitride, aluminum nitride, or indium nitride. The III-V semiconductor may be, for example, gallium phosphide or gallium arsenide. The thickness of the first semiconductor layer may be, for example, from 1 μm to 5 μm. The thickness of the light-emitting layer may be, for example, from 25 nanometers (nm) to 150 nm. The thickness of the second semiconductor layer may be, for example, from 50 nm to 600 nm. The light-emitting element 3 having this configuration can emit light having a peak in the light intensity (also referred to as light intensity) in the wavelength region of 360 nm to 430 nm. More specifically, the light-emitting element 3 can emit light having a spectrum with a peak in the light intensity in the wavelength region of 360 nm to 430 nm. In the present disclosure, the wavelength region of 360 nm to 430 nm is also referred to as the wavelength region of purple light (also referred to as the purple light region).

[0023] The frame body 4 is positioned, for example, so as to surround the light-emitting element 3 on the substrate 2. The material of the frame body 4 may be, for example, a ceramic material, a porous material, or a resin material mixed with powder. The material of the powder may be, for example, a metal oxide. The ceramic material may be, for example, aluminum oxide, titanium oxide, zirconium oxide, or yttrium oxide. The metal oxide may be, for example, aluminum oxide, titanium oxide, zirconium oxide, or yttrium oxide. The frame body 4 is positioned on the first surface 2a of the substrate 2. The frame body 4 may be connected to the first surface 2a of the substrate 2 via, for example, resin, solder, or paste. The frame body 4 is positioned in a form surrounding the light-emitting element 3 in a state where it does not contact the light-emitting element 3, for example. The frame body 4 may have a cylindrical shape having a virtual central axis (also referred to as a virtual center axis) along the normal of the first surface 2a, for example. The frame body 4 may have an inner wall surface 4a whose inner diameter expands as it moves away from the first surface 2a of the substrate 2. In other words, the inner wall surface 4a may be inclined with respect to the virtual central axis in a form that expands in a direction away from the virtual central axis (also referred to as outward) from an end portion on the substrate 2 side (also referred to as the first end portion or the lower end portion) toward an end portion located on the opposite side of the first end portion (also referred to as the second end portion or the upper end portion). In this case, the inner wall surface 4a can function as a surface (also referred to as a reflecting surface) that reflects the light emitted from the light-emitting element 3 in a direction away from the first surface 2a. For example, when the frame body 4 is viewed in plan along the normal of the first surface 2a, the shape of the inner wall surface 4a may be circular. According to this form, the inner wall surface 4a can uniformly reflect the light emitted by the light-emitting element 3 with respect to a region located in a direction away from the first surface 2a around the virtual central axis.

[0024] The frame body 4 may have, for example, a metal layer and a plating layer on the inner wall surface 4a. The material of the metal layer may be a metal such as tungsten, molybdenum, copper, or silver. The plating layer may be in a state of covering the metal layer. The material of the plating layer may be nickel or gold, etc. According to this configuration, the inner wall surface 4a of the frame body 4 can reflect the light emitted by the light-emitting element 3. The angle at which the inner wall surface 4a is inclined with respect to the first surface 2a may be, for example, from 55 degrees to 70 degrees.

[0025] The sealing member 5 is located, for example, in a state of being filled in the space (also referred to as the inner space) surrounded by the first surface 2a of the substrate 2 and the inner wall surface 4a of the frame body 4. The sealing member 5 may, for example, seal the light-emitting element 3. The sealing member 5 has, for example, translucency that allows the light emitted from the light-emitting element 3 to pass through. Here, the sealing member 5 may be located in a state of being filled in a region excluding the region (also referred to as the upper region) along the end on the side opposite to the first surface 2a in the inner space surrounded by the first surface 2a and the inner wall surface 4a. The material of the sealing member 5 may be, for example, a resin having translucency and insulation properties such as a silicone resin, an acrylic resin, or an epoxy resin. The refractive index of the sealing member 5 may be set, for example, from 1.4 to 1.6.

[0026] The wavelength conversion member 6 is located, for example, in a region (upper region) along an end portion on the side opposite to the first surface 2a in the inner space surrounded by the first surface 2a and the inner wall surface 4a. From another perspective, the wavelength conversion member 6 may be attached to the second end portion (upper end portion) of the inner wall surface 4a in a form that closes an opening located on the side opposite to the first surface 2a of the frame body 4. Here, for example, the wavelength conversion member 6 is located along a surface (also referred to as the upper surface) located on the side opposite to the first surface 2a of the sealing member 5. The wavelength conversion member 6 is located, for example, in a form that fits into the inner space of the frame body 4. The wavelength conversion member 6 can, for example, convert the wavelength of the light emitted by the light-emitting element 3. More specifically, the spectrum (also referred to as the spectral distribution) of the light emitted by the light-emitting element 3 can be converted into a different spectrum. The wavelength conversion member 6 has, for example, a base material 61 and a plurality of phosphors 62. Each of the plurality of phosphors 62 may have, for example, a particulate shape.

[0027] The base material 61 may be composed of, for example, a resin or glass having translucency and insulation properties. The resin constituting the base material 61 may be, for example, a resin having translucency such as a fluororesin, a silicone resin, an acrylic resin, or an epoxy resin.

[0028] The plurality of phosphors 62 may be, for example, dispersed and located within the base material 61. Here, a large number of phosphors 62 may be located in a state of being substantially uniformly dispersed, for example, in the wavelength conversion member 6. When the light emitted from the light emitting element 3 enters the inside of the wavelength conversion member 6 through the sealing member 5, the phosphor 62 can be excited by this light and emit light. The light emitted by the light emitting element 3 may be referred to as light for exciting the phosphor 62 (also referred to as excitation light or second light). The phosphor 62 emits light (also referred to as fluorescence) having a wavelength based on the light emission characteristics of the phosphor 62 in response to the irradiation of the excitation light. In other words, the phosphor 62 converts the excitation light emitted by the light emitting element 3 into light (fluorescence) having a spectrum different from that of the excitation light. More specifically, the phosphor 62 converts the excitation light emitted by the light emitting element 3 into light (fluorescence) having a spectrum different from that of the excitation light. Therefore, at least a part of the excitation light emitted by the light emitting element 3 is converted by the wavelength conversion member 6 into light having a spectrum different from that of the excitation light and is emitted to the outside of the light emitting device 1. More specifically, at least a part of the excitation light emitted by the light emitting element 3 is converted by the plurality of phosphors 62 of the wavelength conversion member 6 into light (fluorescence) having a spectrum different from that of the excitation light and is emitted to the outside of the light emitting device 1. Thereby, the wavelength conversion member 6 converts the wavelength of the light emitted by the light emitting element 3.

[0029] Here, among the excitation light emitted by the light-emitting element 3, the portion that is not converted by the wavelength conversion member 6 into light having a spectrum different from that of the excitation light may pass through the wavelength conversion member 6 and be emitted outside the light-emitting device 1 as the excitation light. Here, the light-emitting device 1 emits, toward the outside of the light-emitting device 1, combined light of light (fluorescent light) whose spectrum has been converted from the excitation light by the wavelength conversion member 6 and light (excitation light) that has passed through the wavelength conversion member 6 without its spectrum being converted by the wavelength conversion member 6 and is emitted as it is. The light (first light) emitted by the light-emitting device 1 toward the outside of the light-emitting device 1 may be referred to as light emitted from the light-emitting device 1 toward the outside (also referred to as external emission light). This external emission light corresponds to combined light of light (fluorescent light) whose spectrum has been converted from the excitation light by the wavelength conversion member 6 and light (excitation light) that has passed through the wavelength conversion member 6 without its spectrum being converted by the wavelength conversion member 6 and is emitted as it is.

[0030] The light-emitting device 1 emits light specified by a predetermined spectrum as the first light (external emission light). The spectrum of the light, such as the spectrum (also referred to as spectral distribution) of the first light, can be measured by various measuring instruments including, for example, a spectroscope and a control circuit. The spectrum of the light may be measured using an integrating sphere in addition to the spectroscope. The various measuring instruments may be, for example, commercially available measuring instruments. The spectroscope may be, for example, CL-500A manufactured by Konica Minolta.

[0031] The light-emitting device 1 may have a configuration in which it emits light specified by the spectrum illustrated in FIGS. 4 to 6 as the first light (external emission light).

[0032] FIG. 4 is a graph showing a first example of the spectrum (spectral distribution) of the first light emitted by the light-emitting device 1. FIG. 5 is a graph showing a second example of the spectrum (spectral distribution) of the first light emitted by the light-emitting device 1. FIG. 6 is a graph showing a third example of the spectrum (spectral distribution) of the first light emitted by the light-emitting device 1. In each of the graphs of FIGS. 4 to 6, the horizontal axis represents the wavelength, and the vertical axis represents the relative light intensity. In the present disclosure, the relative light intensity is a relative value of the light intensity when the maximum value of the light intensity in the wavelength range from 350 nm to 800 nm is set to 1. The light intensity (unit: watt per square meter per nanometer (W / m 2 / nm)) is the irradiance of light per unit area and per unit wavelength. The wavelength range from 350 nm to 800 nm substantially coincides with and includes the wavelength range from 360 nm to 780 nm, which is an example of the wavelength range of visible light. In each of the graphs of FIGS. 4 to 6, the spectrum of the first light is indicated by a thick solid line. This thick solid line is a curve macroscopically, although it is a broken line microscopically. Therefore, the thick solid line indicating the spectrum of the first light will be described as a curve indicating the spectrum of the first light. Further, FIG. 7 is a graph showing an example of the spectrum of sunlight. Also in the graph of FIG. 7, as in each of the graphs of FIGS. 4 to 6, the horizontal axis represents the wavelength, the vertical axis represents the relative light intensity, and the spectrum of sunlight is indicated by a thick solid line.

[0033] As shown in FIGS. 4 to 6, the spectrum of the first light (also referred to as the first emission spectrum) emitted by the light-emitting device 1 has, for example, a first peak (also referred to as the first peak) P1 of light intensity, a second peak (also referred to as the second peak) P2 of light intensity, and a third peak (also referred to as the third peak) P3 of light intensity. The first peak P1 exists in the wavelength range from 430 nm to 500 nm. The second peak P2 exists in the wavelength range from 500 nm to 565 nm. The third peak P3 exists in the wavelength range from 620 nm to 750 nm.

[0034] In the present disclosure, the peak of the light intensity in the spectrum of light may be a point (also referred to as a maximum point) where the relative light intensity reaches a maximum value in a graph showing the spectrum of light. From another perspective, the peak of the light intensity in the spectrum of light may be the apex of a mountain-shaped portion located between the shaped portions of two adjacent valleys in the spectrum of light in a graph showing the spectrum of light. Incidentally, for example, the spectrum of light (fluorescence) emitted from a phosphor in response to irradiation with excitation light may have a finely varying light intensity with respect to a fine change in wavelength due to the influence of the characteristics of the phosphor and measurement errors. In other words, in a graph showing the spectrum of light, the spectrum of light may have minute mountain and valley shapes. Therefore, in the present disclosure, in a graph showing the spectrum of light, when the wavelength difference (also referred to as a first wavelength width) between the bottom point (also referred to as a first bottom point) in the shaped portion of the first valley (also referred to as a first valley-shaped portion) and the bottom point (also referred to as a second bottom point) in the shaped portion of the second valley (also referred to as a second valley-shaped portion) adjacent to the first valley-shaped portion in the spectrum of light is equal to or less than a first predetermined value, the apex of the mountain-shaped portion (also referred to as a first mountain-shaped portion) located between the first valley-shaped portion and the second valley-shaped portion in the spectrum of light is not considered to be the peak of the light intensity. The first predetermined value may be set to, for example, 10 nm, 20 nm, or other values. Further, for example, the peak of the light intensity in the spectrum of light may be the maximum value of the relative light intensity in the spectrum of light after smoothing the first valley-shaped portion, the first mountain-shaped portion, and the second valley-shaped portion that constitute a portion having a first wavelength width equal to or less than the first predetermined value with respect to the spectrum of light. Further, for example, in a graph showing the spectrum of light, when at least one of the difference in relative light intensity between the first bottom point and the apex of the first mountain-shaped portion and the difference in relative intensity between the apex of the first mountain-shaped portion and the second bottom point is equal to or less than a second predetermined value, the apex of the first mountain-shaped portion may not be considered to be the peak of the light intensity. The second predetermined value may be set to, for example, 0.01 or other values.

[0035] In the present disclosure, in a graph showing the spectrum of light, the wavelength at which the relative light intensity in the spectrum of light reaches a maximum value may be referred to as the peak wavelength in the spectrum of light. From another perspective, the peak wavelength in the spectrum of light may be the wavelength of the apex of the mountain-shaped portion located between the shaped portions of two adjacent valleys in the spectrum of light in the graph showing the spectrum of light. In the present disclosure, in a graph showing the spectrum of light, when the difference in wavelength (first wavelength width) between the first bottom point and the second bottom point in the spectrum of light is equal to or less than a first predetermined value, the wavelength of the apex of the first mountain-shaped portion located between the first valley-shaped portion and the second valley-shaped portion in the spectrum of light may not be regarded as the peak wavelength. Further, for example, the peak wavelength in the spectrum of light may be the wavelength showing the maximum value of the relative light intensity in the spectrum of light after smoothing the first valley-shaped portion, the first mountain-shaped portion, and the second valley-shaped portion that constitute a portion having a first wavelength width equal to or less than a first predetermined value with respect to the spectrum of light. Further, for example, in a graph showing the spectrum of light, when at least one of the difference in relative light intensity between the first bottom point and the apex of the first mountain-shaped portion and the difference in relative intensity between the apex of the first mountain-shaped portion and the second bottom point is equal to or less than a second predetermined value, the wavelength of the apex of the first mountain-shaped portion may not be regarded as the peak wavelength.

[0036] In the present disclosure, the wavelength range from 430 nm to 500 nm is also referred to as the wavelength range of blue light (also referred to as the blue light region). The wavelength range from 500 nm to 565 nm is also referred to as the wavelength range of green light (also referred to as the green light region). The wavelength range from 565 nm to 590 nm is also referred to as the wavelength range of yellow light (also referred to as the yellow light region). The wavelength range from 590 nm to 620 nm is also referred to as the wavelength range of orange light (also referred to as the orange light region). The wavelength range from 620 nm to 750 nm is also referred to as the wavelength range of red light (also referred to as the red light region).

[0037] In the light-emitting device 1 according to one embodiment, as shown in FIGS. 4 to 6, in the first emission spectrum of the first light emitted by the light-emitting device 1, for example, when the maximum light intensity among the first peak P1, the second peak P2, and the third peak P3 is set to 1, the light intensities of the first peak P1, the second peak P2, and the third peak P3 are each 0.6 or more. In other words, for example, the light intensities of the first peak P1, the second peak P2, and the third peak P3 are each 0.6 times or more the maximum light intensity among the first peak P1, the second peak P2, and the third peak P3. Thereby, in the first emission spectrum of the first light emitted by the light-emitting device 1, the difference in light intensity between the first peak P1 in the blue light region, the second peak P2 in the green light region, and the third peak P3 in the red light region is reduced, so that the color rendering property of the first light emitted by the light-emitting device 1 can be enhanced.

[0038] Further, in the light-emitting device 1 according to one embodiment, as shown in FIGS. 4 to 6, the first emission spectrum of the first light emitted by the light-emitting device 1 has a minimum light intensity value (also referred to as the first minimum value) that is equal to or less than half of the light intensity of each of the second peak P2 and the third peak P3 in the wavelength range of 565 nm to 620 nm. The first minimum value may be, for example, the minimum light intensity in the wavelength range of 565 nm to 620 nm as the yellow light region and the orange light region in the first emission spectrum. From another perspective, the point at which the light intensity (which may be the relative light intensity) in the first emission spectrum becomes the first minimum value may be referred to as the first minimum point Lm1. The first minimum point Lm1 may be, for example, the bottom point (also referred to as the bottom point) of the valley-shaped portion located between the second peak P2 and the third peak P3 in the graph showing the first emission spectrum. In this case, the first emission spectrum of the first light emitted by the light-emitting device 1 has the first minimum point Lm1 in the wavelength range of 565 nm to 620 nm.

[0039] Here, since cyanobacteria have phycocyanin, a pigment that can absorb light in the yellow light region and the orange light region, by reducing the light intensity in the yellow light region to the orange light region in the first emission spectrum, the growth of cyanobacteria by the first light emitted by the light-emitting device 1 can be reduced. Therefore, according to the light-emitting device 1 according to one embodiment, it is possible to reduce the growth of cyanobacteria while enhancing the color rendering property.

[0040] In one embodiment, for example, the light-emitting device 1 may be used for displaying aquatic organisms. Examples of aquatic organisms include fish and shellfish such as tilapia, sea bream, and shrimp, cnidarians such as corals and sea anemones, and seaweeds. In this case, for example, by reducing the growth of cyanobacteria in an aquarium containing aquatic organisms, the occurrence of a problem in which illumination light from an illumination device using the light-emitting device 1 is blocked by unnecessary algae such as cyanobacteria can be reduced. In addition, by enhancing the color rendering property of the illumination light from the illumination device using the light-emitting device 1, the appearance of aquatic organisms can be improved when viewing aquatic organisms in an aquarium or the like. Therefore, it can be said that the light-emitting device 1 is suitable as a light-emitting device used for displaying aquatic organisms.

[0041] In one embodiment, for example, the light-emitting device 1 may be used for growing aquatic organisms. In this case, for example, in a water tank containing aquatic organisms, the growth of cyanobacteria is reduced, so that the occurrence of a problem in which illumination light from an illumination device using the light-emitting device 1 is blocked by unnecessary algae such as cyanobacteria can be reduced. Further, for example, since the first light emitted by the light-emitting device 1 contains well-balanced light components in the blue light region, the green light region, and the red light region, similar to the growth environment of aquatic organisms under sunlight, the growth of aquatic organisms in a water tank or the like can be promoted. Therefore, it can be said that the light-emitting device 1 is suitable as a light-emitting device used for growing aquatic organisms. Here, the growth of aquatic organisms may include, for example, the cultivation of aquatic organisms. In other words, it can also be said that the light-emitting device 1 is suitable as a light-emitting device used for cultivating aquatic organisms. This cultivation of aquatic organisms may include, for example, not only the cultivation of fish, shellfish, and cnidarians in a water tank but also the cultivation of seaweeds in a water tank. For example, regarding the cultivation of seaweeds, after seeding in an onshore water tank, seeding and growth in the sea may be performed. In this case, the light-emitting device 1 can contribute to promoting seeding in the water tank.

[0042] In one embodiment, for example, the light-emitting device 1 may be used for reducing the growth of cyanobacteria. As described above, in the first light emitted by the light-emitting device 1, the light intensity in the yellow light region to the orange light region is reduced, so that the growth of cyanobacteria by the first light emitted by the light-emitting device 1 can be reduced. Therefore, it can be said that the light-emitting device 1 is suitable as a light-emitting device used for reducing the growth of cyanobacteria.

[0043] In an example of the light-emitting device 1 according to one embodiment, for example, the first light having the above-described first emission spectrum may be realized by a combination of the second light emitted by the light-emitting element 3 and the fluorescence emitted by the plurality of phosphors 62.

[0044] Here, for example, the light-emitting device 1 includes a light-emitting element 3 that emits second light and a plurality of phosphors 62, and the plurality of phosphors 62 may include a first phosphor 62a, a second phosphor 62b, and a third phosphor 62c. In other words, for example, the light-emitting device 1 may include a light-emitting element 3 that emits second light, a first phosphor 62a, a second phosphor 62b, and a third phosphor 62c.

[0045] The second light has a peak in the light intensity in the wavelength range of 360 nm to 430 nm as the violet light region. In other words, the spectrum of the second light has a peak in the light intensity in the wavelength range of 360 nm to 430 nm as the violet light region. The spectrum of the second light may have a peak in the light intensity in the wavelength range of 385 nm to 415 nm. For example, when the light-emitting element 3 is an LED in which gallium nitride is applied to the material of the light-emitting element 3, an example of the peak wavelength of the second light may be 405 nm.

[0046] The first phosphor 62a can convert the second light as excitation light into light having a peak in the light intensity in the wavelength range of 430 nm to 500 nm as the blue light region. In other words, the spectrum of the light emitted by the first phosphor 62a in response to the incidence of the second light as excitation light may have a peak in the light intensity in the wavelength range of 430 nm to 500 nm as the blue light region. Further in other words, the first phosphor 62a may be a phosphor (also referred to as a blue phosphor) that can convert excitation light into blue fluorescence. The material of the blue phosphor is, for example, BaMgAl 10 O 17 :Eu, (Sr,Ca,Ba) 10 (PO4)6Cl2:Eu or (Sr,Ba) 10 (PO4)6Cl2:Eu, etc. The ratios of the plurality of elements separated by commas within the parentheses may be arbitrarily set as long as they are within the range of the molecular formula.

[0047] The second phosphor 62b can convert the second light as excitation light into light having a peak in the light intensity in the wavelength range of 500 nm to 565 nm as the green light region. In other words, the spectrum of the light emitted by the second phosphor 62b in response to the incidence of the second light as excitation light may have a peak in the light intensity in the wavelength range of 500 nm to 565 nm as the green light region. Further in other words, the second phosphor 62b may be a phosphor (also referred to as a green phosphor) that can convert excitation light into green fluorescence. The material of the green phosphor may be, for example, SrSi2(O,Cl)2N2:Eu, (Sr,Ba,Mg)2SiO4:Eu 2+ , ZnS:Cu,Al or Zn2SiO4:Mn and the like. The ratios of the plurality of elements separated by commas within the parentheses may be arbitrarily set as long as they are within the range of the molecular formula.

[0048] The third phosphor 62c can convert the second light as excitation light into light having a peak in the light intensity in the wavelength range of 620 nm to 750 nm as the red light region. In other words, the spectrum of the light emitted by the third phosphor 62c in response to the incidence of the second light as excitation light may have a peak in the light intensity in the wavelength range of 620 nm to 750 nm as the red light region. Further in other words, the third phosphor 62c may be a phosphor (also referred to as a red phosphor) that can convert excitation light into red fluorescence. The material of the red phosphor may be, for example, Y2O2S:Eu, Y2O3:Eu, SrCaClAlSiN3:Eu 2+ , CaAlSiN3:Eu or CaAlSi(ON)3:Eu and the like.

[0049] Here, for example, the first emission spectrum may be realized by adjusting the content and selecting the material for each of the first phosphor 62a, the second phosphor 62b, and the third phosphor 62c among the plurality of phosphors 62.

[0050] Then, the first emission spectrum may include a part of the second light emitted from the light-emitting element 3 and have a peak (also referred to as the fourth peak) P4 of the light intensity in the wavelength range of 360 nm to 430 nm as the violet light region. Thereby, by increasing the light component in the violet light region in the first light, the color rendering property of the first light emitted from the light-emitting device 1 can be enhanced.

[0051] In addition, in a light-emitting device using blue excitation light, generally, a phosphor (also referred to as a yellow phosphor) that can convert the excitation light into yellow fluorescence is applied, so that the light mixed with the blue excitation light and the yellow fluorescence is emitted to the outside. On the other hand, by using excitation light having a peak of light intensity in the violet light region, for example, compared with the case of using blue excitation light, a green phosphor in which the emission amount of fluorescence in the green light region is larger than the emission amounts of fluorescence in the yellow light region and the orange light region, and a red phosphor in which the emission amount of fluorescence in the red light region is larger than the emission amounts of fluorescence in the yellow light region and the orange light region can be used. Thereby, in the first emission spectrum of the first light emitted from the light-emitting device 1, the light intensities in the yellow light region and the orange light region can be easily reduced.

[0052] In the light-emitting device 1 according to an embodiment, for example, in the first emission spectrum of the first light, the second peak P2 may be present in the wavelength range of 500 nm to 540 nm in the green light region, and the third peak P3 may be present in the wavelength range of 640 nm to 680 nm in the red light region. According to this configuration, in the first emission spectrum of the first light emitted from the light-emitting device 1, by making the difference between the wavelength of the second peak P2 and the wavelength of the third peak P3 relatively large, the first minimum value can be easily set to be less than or equal to half of the light intensities of the second peak P2 and the third peak P3 respectively. Here, for example, by appropriately selecting the material of the green phosphor, the second peak P2 may be present in the wavelength range of 500 nm to 540 nm in the green light region. For example, by appropriately selecting the material of the red phosphor, the third peak P3 may be present in the wavelength range of 640 nm to 680 nm in the red light region.

[0053] In the first example of the first emission spectrum shown in FIG. 4, the wavelength indicating the first peak P1 (also referred to as the first peak wavelength) is 449 nm, the wavelength indicating the second peak P2 (also referred to as the second peak wavelength) is 522 nm, the wavelength indicating the third peak P3 (also referred to as the third peak wavelength) is 651 nm, and the wavelength indicating the fourth peak P4 (also referred to as the fourth peak wavelength) is 405 nm. The wavelength indicating the first minimum value (also referred to as the first minimum wavelength) is 583 nm. The relative light intensity of the first peak P1 is approximately 0.618, the relative light intensity of the second peak P2 is approximately 0.726, the relative light intensity of the third peak P3 is 1, the relative light intensity of the fourth peak P4 is approximately 0.546, and the first minimum value in the relative light intensity is approximately 0.322. As another example of the first example of the first emission spectrum, the relative light intensity of the first peak P1 may be from 0.6 to 0.65, the relative light intensity of the second peak P2 may be from 0.7 to 0.75, the relative light intensity of the third peak P3 may be 1, the relative light intensity of the fourth peak P4 may be from 0.5 to 0.6, and the first minimum value in the relative light intensity may be from 0.3 to 0.4.

[0054] In the second example of the first emission spectrum shown in FIG. 5, the first peak wavelength indicating the first peak P1 is 451 nm, the second peak wavelength indicating the second peak P2 is 522 nm, the third peak wavelength indicating the third peak P3 is 658 nm, and the fourth peak wavelength indicating the fourth peak P4 is 405 nm. The first minimum wavelength indicating the first minimum value is 586 nm. The relative light intensity of the first peak P1 is approximately 0.902, the relative light intensity of the second peak P2 is approximately 0.853, the relative light intensity of the third peak P3 is 1, the relative light intensity of the fourth peak P4 is approximately 0.647, and the first minimum value in the relative light intensity is approximately 0.353. As another example of the second example of the first emission spectrum, the relative light intensity of the first peak P1 may be from 0.85 to 0.95, the relative light intensity of the second peak P2 may be from 0.8 to 0.9, the relative light intensity of the third peak P3 may be 1, the relative light intensity of the fourth peak P4 may be from 0.6 to 0.7, and the first minimum value in the relative light intensity may be from 0.3 to 0.4.

[0055] In the third example of the first emission spectrum shown in FIG. 6, the first peak wavelength indicating the first peak P1 is 450 nm, the second peak wavelength indicating the second peak P2 is 524 nm, the third peak wavelength indicating the third peak P3 is 656 nm, and the fourth peak wavelength indicating the fourth peak P4 is 405 nm. The first minimum wavelength indicating the first minimum value is 585 nm. The relative light intensity of the first peak P1 is 1, the relative light intensity of the second peak P2 is about 0.683, the relative light intensity of the third peak P3 is about 0.693, the relative light intensity of the fourth peak P4 is about 0.547, and the first minimum value in the relative light intensity is about 0.251. As another example of the third example of the first emission spectrum, the relative light intensity of the first peak P1 may be 1, the relative light intensity of the second peak P2 may be from 0.65 to 0.7, the relative light intensity of the third peak P3 may be from 0.65 to 0.75, the relative light intensity of the fourth peak P4 may be from 0.5 to 0.6, and the first minimum value in the relative light intensity may be from 0.2 to 0.3.

[0056] In the light-emitting device 1 according to an embodiment, for example, the full width at half maximum (also referred to as the first full width at half maximum) of the spectrum of the fluorescence emitted by the green phosphor in response to the irradiation of the excitation light is set to be from 55 nm to 75 nm, and the full width at half maximum (also referred to as the second full width at half maximum) of the spectrum of the fluorescence emitted by the red phosphor in response to the irradiation of the excitation light may be set to be from 80 nm to 105 nm. According to this configuration, by appropriately adjusting each of the first full width at half maximum and the second full width at half maximum, in the first emission spectrum of the first light emitted by the light-emitting device 1, the first minimum value can be easily set to be less than or equal to half of the light intensity of each of the second peak P2 and the third peak P3. Also, in the first emission spectrum of the first light emitted by the light-emitting device 1, it is possible to ensure at least a little light intensity in the yellow light region and the orange light region. Thereby, the color rendering property of the first light emitted from the light-emitting device 1 can be enhanced, and by including to some extent the light components in the yellow light region and the orange light region that are also included in the sunlight in water in the first light emitted by the light-emitting device 1, the first emission spectrum of the first light can be made closer to the spectrum of the sunlight in water. As a result, the growth of aquatic organisms can be promoted by the first light emitted by the light-emitting device 1.

[0057] The first half-value width may be the wavelength width indicating a wavelength region where the light intensity is not less than half of the maximum value of this light intensity in the spectrum of the fluorescence emitted from the green phosphor when the excitation light is irradiated only on the green phosphor. The second half-value width may be the wavelength width indicating a wavelength region where the light intensity is not less than half of the maximum value of this light intensity in the spectrum of the fluorescence emitted from the red phosphor when the excitation light is irradiated only on the red phosphor.

[0058] In the light-emitting device 1 according to one embodiment, for example, the first light emitted by the light-emitting device 1 may be from 4500 Kelvin (K) to 12000 K. The color temperature is a numerical value representing the color of the light emitted by the light source and is expressed using the unit of K (Kelvin). The higher the numerical value of the color temperature, the bluer the light, and the lower the numerical value of the color temperature, the redder the light. For example, in Japanese Industrial Standard (JIS) Z9112:2019, the color temperature of a bulb color is from 2600 K to 3250 K, the color temperature of a warm white color is from 3250 K to 3800 K, the color temperature of a white color is from 3800 K to 4500 K, the color temperature of a day white color is from 4600 K to 5500 K, and the color temperature of a daylight color is from 5700 K to 7100 K. For example, the color of sunlight at around noon is a day white color with a color temperature of about 5000 K. The color of light with a color temperature of about 6500 K, which is higher than the color temperature of the day white color, is a daylight color. The daylight color contains, for example, more components of light in the blue light region or light components with wavelengths shorter than the blue light region than the day white color and appears bluish. Conversely, the day white color appears closer to white than the daylight color. The color temperature of the light can be measured, for example, by a commercially available measuring device having a color temperature measuring function.

[0059] Water absorbs more light in the red light region than in the blue light region. Therefore, for sunlight, in water, depending on the water depth, the light components in the red light region can be absorbed and the components in the blue light region can become relatively more abundant. Thus, for example, if the first light emitted by the light-emitting device 1 is from 4500K to 12000K, the first light emitted by the light-emitting device 1 can be close to the color temperature of sunlight in water corresponding to the water depth from the water's edge. In other words, the color of the first light emitted by the light-emitting device 1 can be close to the color tone in the sea. As a result, by applying the light-emitting device 1 to an illumination device that illuminates aquatic organisms such as fish and shellfish, cnidarians, and seaweeds in an aquarium or the like, the appearance of the aquatic organisms can be improved when appreciating the aquatic organisms in an aquarium or the like.

[0060] Here, the color temperature of the first light emitted by the light-emitting device 1 can be set, for example, by adjusting the content and selecting materials for each of the first phosphor 62a, the second phosphor 62b, and the third phosphor 62c among the plurality of phosphors 62. The color temperature of the first light according to the first example of the first emission spectrum shown in FIG. 4 is about 5000K (specifically 5093K). The color temperature of the first light according to the second example of the first emission spectrum shown in FIG. 5 is about 6500K (specifically 6467K). The color temperature of the first light according to the third example of the first emission spectrum shown in FIG. 6 is about 10000K (specifically 9956K). The color temperature of the first light according to another example of the first example of the first emission spectrum may be from 4500K to 5500K. The color temperature of the first light according to another example of the second example of the first emission spectrum may be from 6000K to 7000K. The color temperature of the first light according to another example of the third example of the first emission spectrum may be from 9500K to 10500K.

[0061] In the light-emitting device 1 according to one embodiment, for example, as shown in FIGS. 4 and 5, in the first emission spectrum of the first light emitted by the light-emitting device 1, the light intensity of the third peak P3 may be 2.5 times or more that of the first minimum value. Thereby, in the first emission spectrum of the first light, the light intensity in the red light region can be increased. As a result, by compensating for the reduction in the light intensity in the yellow light region and the orange light region with the increase in the light intensity in the red light region, the color rendering property of the first light emitted by the light-emitting device 1 can be improved.

[0062] Here, the relative light intensities at the first peak P1, the second peak P2, and the third peak P3 in the first emission spectrum of the first light emitted by the light-emitting device 1 may be set, for example, by adjusting the content and selecting the materials of the first phosphor 62a, the second phosphor 62b, and the third phosphor 62c among the plurality of phosphors 62.

[0063] For example, if the color temperature of the first light is from 4500K to 5500K like the first light according to the first example of the first emission spectrum shown in FIG. 4, the color temperature of the first light can be close to the color temperature of the light emitted from a general lighting device. In this case, for example, even if the light-emitting device 1 that emits the first light with reduced light components in the yellow light region and the orange light region is applied to a lighting device that illuminates aquatic organisms in an aquarium or the like, the sense of discomfort in the appearance of the aquatic organisms can be reduced in a person who views the aquatic organisms in the aquarium or the like.

[0064] For example, if the color temperature of the first light is from 4500K to 7000K like the first light according to the first example of the first emission spectrum shown in FIG. 4 and the first light according to the second example of the first emission spectrum shown in FIG. 5, the color temperature of the first light can be close to the color temperature of the sunlight in a shallows or a waterside where the water depth is small rather than the sunlight in water with a large water depth. In this case, for example, the light-emitting device 1 that emits the first light may be used to illuminate a crab or the like, which is an aquatic organism living in a shallows or a waterside.

[0065] In the light-emitting device 1 according to one embodiment, for example, as shown in FIG. 5, in the first emission spectrum of the first light emitted by the light-emitting device 1, when the maximum value of the light intensity in the wavelength range from 350 nm to 800 nm is set to 1, the light intensity of the first peak P1, the light intensity of the second peak P2, and the light intensity of the third peak P3 may each be 0.8 or more. In other words, for example, in the first emission spectrum of the first light emitted by the light-emitting device 1, the light intensity of each of the first peak P1, the second peak P2, and the third peak P3 may be 0.8 times or more the maximum value of the light intensity in the wavelength range from 350 nm to 800 nm. Thereby, the color temperature of the first light can be made closer to the color temperature of sunlight shown in FIG. 7. As a result, the color rendering property of the illumination light from the illumination device using the light-emitting device 1 is enhanced, so that when viewing aquatic organisms in an aquarium or the like, the appearance of the aquatic organisms can be improved. Further, since the first light contains the light in the blue light region, the light in the green light region, and the light in the red light region in a well-balanced manner to some extent, by using the light-emitting device 1, the growth of aquatic plants such as seaweeds can be promoted.

[0066] In the light-emitting device 1 according to one embodiment, for example, as shown in FIG. 6, in the first emission spectrum of the first light emitted by the light-emitting device 1, the light intensity of the first peak P1 may be greater than the light intensity of either the second peak P2 or the third peak P3. Thereby, the proportion of the light in the blue light region in the first light increases, and the color temperature of the first light can be made closer to the color temperature of sunlight in water. As a result, for example, by applying the light-emitting device 1 to an illumination device that illuminates aquatic organisms such as fish in an aquarium, when viewing the aquatic organisms in the aquarium, the appearance of the aquatic organisms can be improved.

[0067] Here, for example, like the first light according to the third example of the first emission spectrum shown in FIG. 6, if the color temperature of the first light is from 8000 K to 12000 K, the color temperature of the first light can be close to the color temperature of sunlight in water where the water depth is relatively large. In this case, for example, the light-emitting device 1 that emits the first light may be used to illuminate fish or the like, which are aquatic organisms living in water.

[0068] In the light-emitting device 1 according to one embodiment, for example, in the first light emitted by the light-emitting device 1, the light energy in the wavelength range of 565 nm to 620 nm may be 15% or less of the light energy (also referred to as the first light energy) in the wavelength range of 350 nm to 800 nm. Thereby, the light energy in the yellow light region and the orange light region in the first light can be reduced. As a result, the growth of cyanobacteria can be reduced by the first light emitted by the light-emitting device 1.

[0069] In the present disclosure, the light energy in a predetermined wavelength range of the first light is the integrated value of the first emission spectrum in the predetermined wavelength range. More specifically, in the present disclosure, the light energy in a predetermined wavelength range of the first light is the area sandwiched between the curve indicating the relative light intensity of the first emission spectrum and the straight line of the horizontal axis where the relative light intensity is zero for the predetermined wavelength range in the graph as shown in FIGS. 4 to 6 respectively. This area is the integrated value of the relative light intensity per unit wavelength for the predetermined wavelength range. The unit wavelength may be, for example, 1 nm, or may be other lengths such as 0.5 nm or 2 nm. The unit wavelength may be set according to, for example, the wavelength resolution of the measuring instrument that measures the first emission spectrum. The wavelength range of 350 nm to 800 nm substantially coincides with the wavelength range of 360 nm to 780 nm, which is an example of the wavelength range of visible light. Therefore, the light energy (first light energy) in the wavelength range of 350 nm to 800 nm corresponds to the light energy in an example of the wavelength range of visible light. The light energy in the wavelength range of 565 nm to 620 nm is the sum of the light energy in the yellow light region and the light energy in the orange light region. In other words, the light energy in the wavelength range of 565 nm to 620 nm is the light energy in the yellow light region and the orange light region.

[0070] Here, regarding the first light emitted by the light-emitting device 1, the ratio of the light energy in the wavelength range of 565 nm to 620 nm to the light energy in the wavelength range of 350 nm to 800 nm (first light energy) may be set, for example, by adjusting the content and selecting materials for each of the first phosphor 62a, the second phosphor 62b, and the third phosphor 62c among the plurality of phosphors 62. Here, for example, if the wavelength of the first minimum point Lm1 in the first emission spectrum is positioned in the wavelength range of 580 nm to 605 nm, which is the center of the wavelength range of 565 nm to 620 nm as the yellow light region and the orange light region, the light energy in the yellow light region and the orange light region can be easily reduced.

[0071] In the light-emitting device 1 according to an embodiment, for example, in the first light emitted by the light-emitting device 1, the light energy in the wavelength range of 565 nm to 620 nm may be 5% or more of the light energy in the wavelength range of 350 nm to 800 nm (first light energy). Thereby, by including to some extent the light components in the yellow light region and the orange light region, which are also included in the sunlight in water, in the first light, the first emission spectrum of the first light can be made closer to the spectrum of the sunlight in water. As a result, the growth of aquatic organisms can be promoted by the first light emitted by the light-emitting device 1. In the first light emitted by the light-emitting device 1, the light energy in the wavelength range of 565 nm to 620 nm may be 5% or more and less than 15% of the first light energy, or may be 5% or more and less than 12% of the first light energy, or may be 5% or more and less than 10% of the first light energy.

[0072] Regarding the first light according to the first example of the first emission spectrum shown in FIG. 4, the light energy in the wavelength range of 565 nm to 620 nm is about 11.8% of the first light energy. The light energy in the blue light region is about 17.4% of the first light energy. The light energy in the green light region is about 20.3% of the first light energy. The light energy in the red light region is about 42.5% of the first light energy.

[0073] Regarding the first light according to the second example of the first emission spectrum shown in FIG. 5, the light energy in the wavelength range from 565 nm to 620 nm is about 11% of the first light energy. The light energy in the blue light region is about 21.9% of the first light energy. The light energy in the green light region is about 21.2% of the first light energy. The light energy in the red light region is about 37.6% of the first light energy.

[0074] Regarding the first light according to the third example of the first emission spectrum shown in FIG. 6, the light energy in the wavelength range from 565 nm to 620 nm is about 9.8% of the first light energy. The light energy in the blue light region is about 28% of the first light energy. The light energy in the green light region is about 20.9% of the first light energy. The light energy in the red light region is about 32.5% of the first light energy.

[0075] <2. Configuration of the lighting device> FIG. 8 is a schematic view showing an external appearance of an example of the lighting device 10. FIG. 9 is an exploded perspective view showing an example of the lighting device 10. A right-handed XYZ coordinate system is attached to FIGS. 8 and 9. And, one direction along the longitudinal direction of the lighting device 10 is taken as the +X direction, one direction along the width direction of the lighting device 10 which is perpendicular to the +X direction is taken as the +Y direction, and one direction along the thickness direction of the lighting device 10 which is perpendicular to the +X direction and perpendicular to the +Y direction is taken as the +Z direction. An example of the lighting device 10 has a configuration that emits light toward the -Z direction. For this reason, for example, when an example of the lighting device 10 is installed on the ceiling, the -Z direction may be taken as the direction along the gravitational direction.

[0076] As shown in FIGS. 8 and 9, the lighting device 10 may include, for example, the light-emitting device 1 as a part of the lighting device 10. The lighting device 10 may include, for example, a plurality of light-emitting devices 1. In this case, the lighting device 10 emits, as the third light (also referred to as illumination light), the combined light emitted by each of the plurality of light-emitting devices 1. The spectrum of the third light (also referred to as the second emission spectrum) emitted by the lighting device 10 may be a spectrum having substantially the same characteristics as the above-described first emission spectrum. For example, the second emission spectrum of the third light emitted by the lighting device 10 as a whole may have substantially the same characteristics as the spectra illustrated in FIGS. 4 to 6.

[0077] As shown in FIGS. 8 and 9, the lighting device 10 has, for example, an elongated rectangular parallelepiped shape having a longitudinal direction along the +X direction as the first direction. The lighting device 10 includes, for example, a housing 11, a wiring board 12, a plurality of light-emitting devices 1, and a translucent substrate 13. The housing 11 houses, for example, the wiring board 12 and the plurality of light-emitting devices 1. The lighting device 10 emits, for example, the light emitted by the plurality of light-emitting devices 1 within the housing 11 to the outside of the housing 11.

[0078] The housing 11 has, for example, an elongated rectangular parallelepiped outer shape having a longitudinal direction along the +X direction as the first direction and a width direction along the +Y direction as the second direction. The housing 11 has an opening facing the -Z direction as the third direction perpendicular to the longitudinal direction of the housing 11. The housing 11 has, for example, a function of holding the translucent substrate 13 and a function of dissipating the heat generated by the plurality of light-emitting devices 1 to the outside. The material of the housing 11 may be, for example, a metal such as aluminum, copper, or stainless steel, or may be plastic or resin, etc.

[0079] The housing 11 has, for example, a main body 21 and two lid parts 22. The main body 21 has, for example, a longitudinal direction along the +X direction as the first direction and a width direction along the +Y direction as the second direction. And the main body 21 has, for example, an opening 210 facing the -Z direction and openings 211 located at both ends in the longitudinal direction along the +X direction. More specifically, the main body 21 may have, for example, a bottom part 21a and a pair of holding parts 21b. The bottom part 21a may be, for example, a plate-like part having an elongated rectangular front surface and back surface. Each of the front surface and the back surface may have a longitudinal direction along the +X direction as the first direction and a short-side direction along the +Y direction as the second direction. The pair of holding parts 21b may have a form protruding in the -Z direction from each of both ends in the short-side direction of the bottom part 21a. Each of the pair of holding parts 21b may be, for example, a plate-like part having an elongated rectangular front surface and back surface. Each of the front surface and the back surface may have a longitudinal direction along the +X direction as the first direction and a short-side direction along the -Z direction as the third direction. The two lid parts 22 close the openings 211 located at both ends in the longitudinal direction along the +X direction of the main body 21, respectively. Also, each holding part 21b has, for example, a groove extending along the +X direction for holding the light-transmissive substrate 13 in a portion near the end in the -Z direction. In other words, the pair of grooves are positioned so as to face each other. The length of the housing 11 in the longitudinal direction (+X direction) may be set, for example, from 100 millimeters (mm) to 2000 mm.

[0080] The wiring board 12 is located, for example, in a state of being fixed to the housing 11 within the housing 11. The wiring board 12 is in a state of being fixed to the surface facing the -Z direction within the housing 11. The wiring board 12 may be a printed circuit board such as a rigid board, a flexible board, or a rigid-flexible board, for example. The wiring board 12 may have, for example, a plate-like shape having an elongated rectangular front surface and back surface.

[0081] A plurality of light-emitting devices 1 are, for example, mounted on a wiring board 12 inside a housing 11. The plurality of light-emitting devices 1 may be arranged, for example, along a virtual straight line along the longitudinal direction of the housing 11. The wiring conductors of the substrate 2 in the light-emitting device 1 may be electrically connected to the wiring of the wiring board 12 via solder or a conductive adhesive, for example.

[0082] Here, a signal from the wiring board 12 may be transmitted to the light-emitting element 3 via the substrate 2, so that the light-emitting element 3 can emit light. Electric power may be supplied to the wiring board 12 from an external power source via wiring. The power source may be, for example, a button battery or various other power sources. The wiring board 12 may be mounted with a control unit capable of outputting a control signal for controlling the light-emitting element 3. The control unit may be composed of, for example, a processor or the like.

[0083] The translucent substrate 13 is located, for example, in a state of closing an opening facing the -Z direction of the housing 11. For example, the translucent substrate 13 may be held by a pair of holding portions 21b at a position separated from the plurality of light-emitting devices 1 in the -Z direction. For example, the translucent substrate 13 is inserted into one of the openings 211 located at both longitudinal ends along the +X direction of the main body portion 21 into a pair of groove portions in the pair of holding portions 21b, and can be held by the pair of holding portions 21b by being slid along the -X direction or the +X direction. As the material of the translucent substrate 13, a material that allows light emitted from the light-emitting device 1 to pass through is applied. The material of the translucent substrate 13 may be, for example, an acrylic resin or glass. The translucent substrate 13 may be, for example, a plate-like body having elongated rectangular front and back surfaces. The length along the longitudinal direction (+X direction) of the translucent substrate 13 may be, for example, from 98 mm to 1998 mm.

[0084] FIG. 10 is a diagram showing a first example of the spectrum (second emission spectrum) of the third light emitted by the lighting device 10. FIG. 11 is a diagram showing a second example of the spectrum (second emission spectrum) of the third light emitted by the lighting device 10. FIG. 12 is a diagram showing a third example of the spectrum (second emission spectrum) of the third light emitted by the lighting device 10. In each graph of FIGS. 10 to 12, as in each graph of FIGS. 4 to 6, the horizontal axis represents wavelength and the vertical axis represents relative light intensity, and the spectrum of the third light is shown by a thick solid line. This thick solid line is a broken line microscopically but a curve macroscopically. Therefore, the thick solid line indicating the spectrum of the third light will be described as a curve indicating the spectrum of the third light.

[0085] The spectrum (second emission spectrum) of the third light emitted by the light emitting device 1 has, for example, a fifth peak (also referred to as the fifth peak) P5 of light intensity, a sixth peak (also referred to as the sixth peak) P6 of light intensity, and a seventh peak (also referred to as the seventh peak) P7 of light intensity. The fifth peak P5 exists in the wavelength range of 430 nm to 500 nm. The sixth peak P6 exists in the wavelength range of 500 nm to 565 nm. The seventh peak P7 exists in the wavelength range of 620 nm to 750 nm.

[0086] In the lighting device 10 according to an embodiment, as shown in FIGS. 10 to 12, in the second emission spectrum of the third light emitted by the lighting device 10, for example, when the maximum light intensity among the fifth peak P5, the sixth peak P6, and the seventh peak P7 is set to 1, the light intensities of the fifth peak P5, the sixth peak P6, and the seventh peak P7 are each 0.6 or more. In other words, for example, the light intensities of the fifth peak P5, the sixth peak P6, and the seventh peak P7 are each 0.6 times or more the maximum light intensity among the fifth peak P5, the sixth peak P6, and the seventh peak P7. Thereby, in the second emission spectrum of the third light emitted by the lighting device 10, the difference in light intensity between the fifth peak P5 in the blue light region, the sixth peak P6 in the green light region, and the seventh peak P7 in the red light region is reduced, so that the color rendering property of the third light emitted by the lighting device 10 can be enhanced.

[0087] Also, in the lighting device 10 according to one embodiment, for example, as shown in FIGS. 10 to 12, the second emission spectrum of the third light emitted by the lighting device 10 has a minimum value of light intensity (also referred to as the second minimum value) that is less than or equal to half of the light intensity of each of the sixth peak P6 and the seventh peak P7 in the wavelength range of 565 nm to 620 nm. The second minimum value may be, for example, the minimum value of the light intensity in the wavelength range of 565 nm to 620 nm as the yellow light region and the orange light region in the second emission spectrum. From another perspective, the point at which the light intensity (which may be the relative light intensity) becomes the second minimum value in the second emission spectrum may be referred to as the second minimum point Lm2. The second minimum point Lm2 may be, for example, the bottom point (bottom point) of the valley-shaped portion located between the sixth peak P6 and the seventh peak P7 in the graph showing the second emission spectrum. In this case, the second emission spectrum of the third light emitted by the lighting device 10 has the second minimum point Lm2 in the wavelength range of 565 nm to 620 nm.

[0088] Here, as described above, since cyanobacteria have phycocyanin, a pigment that can absorb light in the yellow light region and the orange light region, by reducing the light intensity in the yellow light region to the orange light region in the second emission spectrum, the growth of cyanobacteria by the third light emitted by the lighting device 10 can be reduced. Therefore, according to the lighting device 10 according to one embodiment, it is possible to reduce the growth of cyanobacteria while enhancing the color rendering property.

[0089] In the lighting device 10 according to an embodiment, for example, in the second emission spectrum of the third light, the sixth peak P6 may be present in the wavelength range of 500 nm to 540 nm in the green light region, and the seventh peak P7 may be present in the wavelength range of 640 nm to 680 nm in the red light region. According to this configuration, in the second emission spectrum of the third light emitted by the lighting device 10, by making the difference between the wavelength of the sixth peak P6 and the wavelength of the seventh peak P7 relatively large to some extent, the second minimum value can be easily set to be less than or equal to half of the light intensity of each of the sixth peak P6 and the seventh peak P7. Here, for example, by appropriately selecting the material of the green phosphor, the sixth peak P6 may be present in the wavelength range of 500 nm to 540 nm in the green light region. For example, by appropriately selecting the material of the red phosphor, the seventh peak P7 may be present in the wavelength range of 640 nm to 680 nm in the red light region.

[0090] In the first example of the second emission spectrum shown in FIG. 10, the wavelength indicating the fifth peak P5 (also referred to as the fifth peak wavelength) is 449 nm, the wavelength indicating the sixth peak P6 (also referred to as the sixth peak wavelength) is 522 nm, and the wavelength indicating the seventh peak P7 (also referred to as the seventh peak wavelength) is 651 nm. The wavelength indicating the second minimum value (also referred to as the second minimum wavelength) is 583 nm. The relative light intensity of the fifth peak P5 is about 0.618, the relative light intensity of the sixth peak P6 is about 0.726, the relative light intensity of the seventh peak P7 is 1, and the second minimum value in the relative light intensity is about 0.322. As another example of the first example of the second emission spectrum, the relative light intensity of the fifth peak P5 may be from 0.6 to 0.65, the relative light intensity of the sixth peak P6 may be from 0.7 to 0.75, the relative light intensity of the seventh peak P7 may be 1, and the second minimum value in the relative light intensity may be from 0.3 to 0.4.

[0091] In the second example of the second emission spectrum shown in FIG. 11, the fifth peak wavelength indicating the fifth peak P5 is 451 nm, the sixth peak wavelength indicating the sixth peak P6 is 522 nm, and the seventh peak wavelength indicating the seventh peak P7 is 658 nm. The second minimum wavelength indicating the second minimum value is 586 nm. The relative light intensity of the fifth peak P5 is about 0.902, the relative light intensity of the sixth peak P6 is about 0.853, the relative light intensity of the seventh peak P7 is 1, and the second minimum value in the relative light intensity is about 0.353. As other examples of the second example of the second emission spectrum, the relative light intensity of the fifth peak P5 may be from 0.85 to 0.95, the relative light intensity of the sixth peak P6 may be from 0.8 to 0.9, the relative light intensity of the seventh peak P7 may be 1, and the second minimum value in the relative light intensity may be from 0.3 to 0.4.

[0092] In the third example of the second emission spectrum shown in FIG. 12, the fifth peak wavelength indicating the fifth peak P5 is 450 nm, the sixth peak wavelength indicating the sixth peak P6 is 524 nm, and the seventh peak wavelength indicating the seventh peak P7 is 656 nm. The second minimum wavelength indicating the second minimum value is 585 nm. The relative light intensity of the fifth peak P5 is 1, the relative light intensity of the sixth peak P6 is about 0.683, the relative light intensity of the seventh peak P7 is about 0.693, and the second minimum value in the relative light intensity is about 0.251. As other examples of the third example of the second emission spectrum, the relative light intensity of the fifth peak P5 may be 1, the relative light intensity of the sixth peak P6 may be from 0.65 to 0.7, the relative light intensity of the seventh peak P7 may be from 0.65 to 0.75, and the second minimum value in the relative light intensity may be from 0.2 to 0.3.

[0093] In the lighting device 10 according to an embodiment, for example, the half-value width (first half-value width) of the spectrum of the fluorescence emitted by the green phosphor in response to the irradiation of the excitation light may be set to 55 nm to 75 nm, and the half-value width (second half-value width) of the spectrum of the fluorescence emitted by the red phosphor in response to the irradiation of the excitation light may be set to 80 nm to 105 nm. According to this configuration, by reducing each of the first half-value width and the second half-value width to some extent, in the second emission spectrum of the third light emitted by the lighting device 10, the second minimum value can be easily set to be less than or equal to half of the light intensity of each of the sixth peak P6 and the seventh peak P7. Also, in the second emission spectrum of the third light emitted by the lighting device 10, the light intensity in the yellow light region and the orange light region can be ensured to some extent. As a result, the color rendering property of the third light as the illumination light emitted from the lighting device 10 can be enhanced, and by including to some extent the light components in the yellow light region and the orange light region, which are also included in the sunlight in water, in the third light emitted by the lighting device 10, the second emission spectrum of the third light can be made closer to the spectrum of the sunlight in water. As a result, the growth of aquatic organisms can be promoted by the third light as the illumination light emitted by the lighting device 10.

[0094] In one embodiment, for example, as shown in FIGS. 10 to 12, the second emission spectrum may have a peak (also referred to as the eighth peak) P8 of the light intensity in the wavelength range of 360 nm to 430 nm as the violet light region. Thereby, by increasing the light component in the violet light region in the third light, the color rendering property of the third light emitted from the lighting device 10 can be enhanced. In the first example of the second emission spectrum shown in FIG. 10, the wavelength indicating the eighth peak P8 (also referred to as the eighth peak wavelength) is 405 nm, and the relative light intensity of the eighth peak P8 is about 0.546. As another example of the first example of the second emission spectrum, the relative light intensity of the eighth peak P8 may be from 0.5 to 0.6. In the second example of the second emission spectrum shown in FIG. 11, the eighth peak wavelength indicating the eighth peak P8 is 405 nm, and the relative light intensity of the eighth peak P8 is about 0.647. As another example of the second example of the second emission spectrum, the relative light intensity of the eighth peak P8 may be from 0.6 to 0.7. In the third example of the second emission spectrum shown in FIG. 12, the eighth peak wavelength indicating the eighth peak P8 is 405 nm, and the relative light intensity of the eighth peak P8 is about 0.547. As another example of the third example of the second emission spectrum, the relative light intensity of the eighth peak P8 may be from 0.5 to 0.6.

[0095] In one embodiment, for example, the lighting device 10 may be used for displaying aquatic organisms. In this case, for example, in a water tank containing aquatic organisms, by reducing the growth of cyanobacteria, the occurrence of a problem that the third light as the illumination light from the lighting device 10 is blocked by unnecessary algae such as cyanobacteria can be reduced. In addition, by enhancing the color rendering property of the third light from the lighting device 10, the appearance of the aquatic organisms can be improved when viewing the aquatic organisms in the water tank or the like. Therefore, it can be said that the lighting device 10 is suitable as a lighting device for displaying aquatic organisms.

[0096] In one embodiment, for example, the lighting device 10 may be used for cultivating aquatic organisms. In this case, for example, in an aquarium containing aquatic organisms, the growth of cyanobacteria is reduced, so that the occurrence of a problem in which the third light as illumination light from the lighting device 10 is blocked by unnecessary algae such as cyanobacteria can be reduced. Also, for example, since the third light emitted by the lighting device 10 contains the light components in the blue light region, the green light region, and the red light region in a well-balanced manner, similar to the growth environment of aquatic organisms under sunlight, the growth of aquatic organisms in an aquarium or the like can be promoted. Therefore, it can be said that the lighting device 10 is suitable as a lighting device used for cultivating aquatic organisms. Here, the cultivation of aquatic organisms may include, for example, the aquaculture of aquatic organisms. In other words, it may also be said that the lighting device 10 is suitable as a lighting device used for the aquaculture of aquatic organisms. This aquaculture of aquatic organisms may include, for example, not only the aquaculture of fish, shellfish, and cnidarians in an aquarium but also the aquaculture of seaweeds in an aquarium.

[0097] In one embodiment, for example, the lighting device 10 may be used for reducing the growth of cyanobacteria. As described above, in the third light as illumination light emitted by the lighting device 10, the light intensity in the yellow light region to the orange light region is reduced, so that the growth of cyanobacteria by the third light emitted by the lighting device 10 can be reduced. Therefore, it can be said that the lighting device 10 is suitable as a lighting device used for reducing the growth of cyanobacteria.

[0098] In the lighting device 10 according to one embodiment, for example, the third light emitted by the lighting device 10 may be from 4500K to 12000K. In this case, the third light emitted by the lighting device 10 can be close to the color temperature of sunlight in water according to the water depth. In other words, the color of the third light emitted by the lighting device 10 can be close to the color tone of the sea. As a result, for example, by applying the lighting device 10 to a lighting device that illuminates aquatic organisms such as fish, shellfish, cnidarians, and seaweeds in an aquarium or the like, the appearance of the aquatic organisms can be improved when viewing the aquatic organisms in an aquarium or the like.

[0099] Here, the color temperature of the third light emitted by the lighting device 10 may be set, for example, by adjusting the content and selecting materials for each of the first phosphor 62a, the second phosphor 62b, and the third phosphor 62c among the plurality of phosphors 62. The color temperature of the third light according to the first example of the second emission spectrum shown in FIG. 10 is about 5000K (specifically 5093K). The color temperature of the third light according to the second example of the second emission spectrum shown in FIG. 11 is about 6500K (specifically 6467K). The color temperature of the third light according to the third example of the second emission spectrum shown in FIG. 12 is about 10000K (specifically 9956K). The color temperature of the third light according to another example of the first example of the second emission spectrum may be from 4500K to 5500K. The color temperature of the third light according to another example of the second example of the second emission spectrum may be from 6000K to 7000K. The color temperature of the third light according to another example of the third example of the second emission spectrum may be from 9500K to 10500K.

[0100] In the lighting device 10 according to one embodiment, for example, as shown in FIGS. 10 and 11, in the second emission spectrum of the third light emitted by the lighting device 10, the light intensity of the seventh peak P7 may be 2.5 times or more that of the second minimum value. Thereby, in the second emission spectrum of the third light, the light intensity in the red light region can be increased. As a result, by compensating for the reduction in the light intensity in the yellow light region and the orange light region with the increase in the light intensity in the red light region, the color rendering property of the third light as the illumination light emitted by the lighting device 10 can be improved.

[0101] Here, the relative light intensity at each of the fifth peak P5, the sixth peak P6, and the seventh peak P7 in the second emission spectrum of the third light emitted by the lighting device 10 may be set, for example, by adjusting the content and selecting materials for each of the first phosphor 62a, the second phosphor 62b, and the third phosphor 62c among the plurality of phosphors 62.

[0102] For example, like the third light according to the first example of the second emission spectrum shown in FIG. 10, if the color temperature of the third light is from 4500K to 5500K, the color temperature as the third light can be close to the color temperature of the light emitted from a general lighting device. In this case, for example, even if a lighting device 10 that emits the third light with reduced light components in the yellow light region and the orange light region is applied to a lighting device for illuminating aquatic organisms in an aquarium or the like, the occurrence of a sense of incongruity in the appearance of the aquatic organisms can be reduced in a person who views the aquatic organisms in the aquarium or the like.

[0103] For example, like the third light according to the first example of the second emission spectrum shown in FIG. 10 and the third light according to the second example of the second emission spectrum shown in FIG. 11, if the color temperature of the third light is from 4500K to 7000K, the color temperature of the third light can be close to the color temperature of sunlight in a shallows or waterside where the water depth is small rather than sunlight in water with a large water depth. In this case, for example, the lighting device 10 that emits the third light may be used to illuminate, for example, crabs or the like, which are aquatic organisms living in a shallows or waterside.

[0104] In the lighting device 10 according to one embodiment, for example, as shown in FIG. 11, in the second emission spectrum of the third light emitted by the lighting device 10, when the maximum value of the light intensity in the wavelength range from 350 nm to 800 nm is set to 1, the light intensity of the fifth peak P5, the light intensity of the sixth peak P6, and the light intensity of the seventh peak P7 may each be 0.8 or more. In other words, for example, in the second emission spectrum of the third light emitted by the lighting device 10, the light intensity of each of the fifth peak P5, the sixth peak P6, and the seventh peak P7 may be 0.8 times or more the maximum value of the light intensity in the wavelength range from 350 nm to 800 nm. Thereby, the color temperature of the third light can be made closer to the color temperature of sunlight shown in FIG. 7. As a result, since the color rendering property of the third light as illumination light from the lighting device 10 is enhanced, when viewing aquatic organisms in an aquarium or the like, the appearance of the aquatic organisms can be improved. Further, since the third light contains light in the blue light region, light in the green light region, and light in the red light region to some extent in a well-balanced manner, by using the lighting device 10, the growth of aquatic plants such as seaweeds can be promoted.

[0105] In the lighting device 10 according to one embodiment, for example, as shown in FIG. 12, in the second emission spectrum of the third light emitted by the lighting device 10, the light intensity of the fifth peak P5 may be greater than the light intensity of either the sixth peak P6 or the seventh peak P7. Thereby, the proportion of the light component in the blue light region in the third light increases, and the color temperature of the third light can be made closer to the color temperature of sunlight in water. As a result, for example, by applying the lighting device 10 to a lighting device that illuminates underwater organisms such as fish in an aquarium, when viewing the underwater organisms in the aquarium, the appearance of the underwater organisms can be improved.

[0106] Here, for example, like the third light according to the third example of the second emission spectrum shown in FIG. 12, if the color temperature of the third light is from 8000 K to 12000 K, the color temperature of the third light can be close to the color temperature of sunlight in water where the water depth is relatively large. In this case, for example, the lighting device 10 that emits the third light may be used to illuminate fish or the like, which are underwater organisms living in water.

[0107] In the lighting device 10 according to an embodiment, for example, in the third light emitted by the lighting device 10, the light energy in the wavelength range of 565 nm to 620 nm may be 15% or less of the light energy in the wavelength range of 350 nm to 800 nm (also referred to as the second light energy). Thereby, the light energy in the yellow light region and the orange light region in the third light can be reduced. As a result, the growth of cyanobacteria can be reduced by the third light emitted by the lighting device 10.

[0108] In the present disclosure, the light energy in a predetermined wavelength region of the third light is the integrated value of the second emission spectrum in the predetermined wavelength region. More specifically, in the present disclosure, the light energy in a predetermined wavelength region of the third light is the area sandwiched between the curve indicating the relative light intensity of the second emission spectrum and the straight line of the horizontal axis where the relative light intensity is zero for the predetermined wavelength region in the graphs respectively shown in FIGS. 10 to 12. This area is the integrated value of the relative light intensity per unit wavelength for the predetermined wavelength region. The unit wavelength may be, for example, 1 nm, or may be other lengths such as 0.5 nm or 2 nm. The unit wavelength may be set according to, for example, the wavelength resolution of the measuring instrument that measures the second emission spectrum.

[0109] Here, regarding the third light emitted by the lighting device 10, the ratio of the light energy in the wavelength range of 565 nm to 620 nm to the light energy in the wavelength range of 350 nm to 800 nm (the second light energy) may be set, for example, by adjusting the content and selecting the material for each of the first phosphor 62a, the second phosphor 62b, and the third phosphor 62c in the plurality of phosphors 62. Here, for example, if the wavelength of the second minimum point Lm2 in the second emission spectrum is positioned in the wavelength range of 580 nm to 605 nm at the center of the wavelength range of 565 nm to 620 nm as the yellow light region and the orange light region, the light energy in the yellow light region and the orange light region can be easily reduced.

[0110] In the lighting device 10 according to one embodiment, for example, in the third light emitted by the lighting device 10, the light energy in the wavelength range of 565 nm to 620 nm may be 5% or more of the light energy (second light energy) in the wavelength range of 350 nm to 800 nm. Thereby, by including to some extent the light components in the yellow light region and the orange light region, which are also included in the sunlight in water, in the third light, the second emission spectrum of the third light can be made closer to the spectrum of the sunlight in water. As a result, the growth of aquatic organisms can be promoted by the third light emitted by the lighting device 10. In the third light emitted by the lighting device 10, the light energy in the wavelength range of 565 nm to 620 nm may be 5% or more and less than 15% of the second light energy, may be 5% or more and less than 12% of the second light energy, or may be 5% or more and less than 10% of the second light energy.

[0111] Regarding the third light according to the first example of the second emission spectrum shown in FIG. 10, the light energy in the wavelength range of 565 nm to 620 nm is about 11.8% of the second light energy. The light energy in the blue light region is about 17.4% of the second light energy. The light energy in the green light region is about 20.3% of the second light energy. The light energy in the red light region is about 42.5% of the second light energy.

[0112] Regarding the third light according to the second example of the second emission spectrum shown in FIG. 11, the light energy in the wavelength range of 565 nm to 620 nm is about 11% of the second light energy. The light energy in the blue light region is about 21.9% of the second light energy. The light energy in the green light region is about 21.2% of the second light energy. The light energy in the red light region is about 37.6% of the second light energy.

[0113] Regarding the third light according to the third example of the second emission spectrum shown in FIG. 12, the light energy in the wavelength range from 565 nm to 620 nm is about 9.8% of the second light energy. The light energy in the blue light region is about 28% of the second light energy. The light energy in the green light region is about 20.9% of the second light energy. The light energy in the red light region is about 32.5% of the second light energy.

[0114] <Summary of One Embodiment> In the light-emitting device 1 according to one embodiment, the first emission spectrum of the first light emitted by the light-emitting device 1 has a first peak P1 of light intensity in the wavelength range from 430 nm to 500 nm, a second peak P2 of light intensity in the wavelength range from 500 nm to 565 nm, and a third peak P3 of light intensity in the wavelength range from 620 nm to 750 nm. In the first emission spectrum of the first light emitted by the light-emitting device 1, when the maximum light intensity among the first peak P1, the second peak P2, and the third peak P3 is set to 1, the light intensities of the first peak P1, the second peak P2, and the third peak P3 are each 0.6 or more. The first emission spectrum of the first light emitted by the light-emitting device 1 has a first minimum value of light intensity that is less than or equal to half of the light intensities of the second peak P2 and the third peak P3 in the wavelength range from 565 nm to 620 nm. According to this configuration, in the first emission spectrum of the first light emitted by the light-emitting device 1, the difference in light intensity between the first peak P1 in the blue light region, the second peak P2 in the green light region, and the third peak P3 in the red light region is reduced, so that the color rendering property of the first light emitted by the light-emitting device 1 can be improved. Also, in the first light emitted by the light-emitting device 1, by reducing the light intensity in the yellow light region to the orange light region that can be absorbed by phycocyanin, which is a pigment of cyanobacteria, the growth of cyanobacteria can be reduced. Therefore, for the light-emitting device 1, it is possible to reduce the growth of cyanobacteria while enhancing the color rendering property.

[0115] Also, in the lighting device 10 according to one embodiment, the second emission spectrum of the third light emitted by the lighting device 10 has a fifth peak P5 of the light intensity in the wavelength range from 430 nm to 500 nm, a sixth peak P6 of the light intensity in the wavelength range from 500 nm to 565 nm, and a seventh peak P7 of the light intensity in the wavelength range from 620 nm to 750 nm. In the second emission spectrum of the third light emitted by the lighting device 10, when the maximum light intensity among the fifth peak P5, the sixth peak P6, and the seventh peak P7 is set to 1, the light intensities of the fifth peak P5, the sixth peak P6, and the seventh peak P7 are each 0.6 or more. The second emission spectrum of the third light emitted by the lighting device 10 has a second minimum value of the light intensity that is less than or equal to half of the light intensities of the sixth peak P6 and the seventh peak P7, respectively, in the wavelength range from 565 nm to 620 nm. According to this configuration, in the second emission spectrum of the third light emitted by the lighting device 10, the difference in light intensity between the fifth peak P5 in the blue light region, the sixth peak P6 in the green light region, and the seventh peak P7 in the red light region is reduced, so that the color rendering property of the third light as the illumination light emitted by the lighting device 10 can be improved. Further, in the third light emitted by the lighting device 10, by reducing the light intensity in the yellow light region to the orange light region that can be absorbed by phycocyanin, which is a pigment of cyanobacteria, the growth of cyanobacteria can be reduced. Therefore, for the lighting device 10, it is possible to reduce the growth of cyanobacteria while enhancing the color rendering property.

[0116] <4. Other Embodiments> The present disclosure is not limited to the above-described one embodiment, and various changes and improvements can be made without departing from the gist of the present disclosure.

[0117] In the above-described one embodiment, the example in which the first emission spectrum has the fourth peak P4 and the example in which the second emission spectrum has the eighth peak P8 have been described, but the present disclosure is not limited thereto. For example, the first emission spectrum may not have the fourth peak P4, and the second emission spectrum may not have the eighth peak P8.

[0118] Here, for example, based on the light-emitting device 1 according to the above-described embodiment, the light-emitting element 3 may be a light-emitting element that emits excitation light having a spectrum with a peak in the blue light region, and the plurality of phosphors 62 may not include the first phosphor 62a. In this case, for example, the light-emitting device 1 combines a part of the blue excitation light that has passed through the wavelength conversion member 6, green fluorescence emitted by the green phosphor as the second phosphor 62b in the wavelength conversion member 6 in response to irradiation with the blue excitation light, and red fluorescence emitted by the red phosphor as the third phosphor 62c in the wavelength conversion member 6 in response to irradiation with the excitation light, and emits the combined light as the first light. According to this configuration, the first emission spectrum can be a spectrum that does not have the fourth peak P4, and the second emission spectrum can be a spectrum that does not have the eighth peak P8.

[0119] Further, here, for example, based on the light-emitting device 1 according to the above-described embodiment, the light-emitting device 1 may further include a filter (also referred to as a purple light cut filter) that reduces the transmittance of light in the purple light region and transmits light in the blue light region, green light region, and red light region on a surface opposite to the light-emitting element 3 of the wavelength conversion member 6. The purple light cut filter may be, for example, a long-pass filter that reflects or absorbs light in the purple light region. The long-pass filter may be, for example, a dielectric multilayer film having a structure in which a plurality of thin films of a dielectric are repeatedly laminated. The dielectric may be, for example, one or more materials among titanium oxide (TiO2), silicon dioxide (SiO2), niobium pentoxide (Nb2O5), tantalum pentoxide (Ta2O5), and magnesium fluoride (MgF2). According to this configuration, the first emission spectrum can be a spectrum that does not have the fourth peak P4, and the second emission spectrum can be a spectrum that does not have the eighth peak P8.

[0120] Further, here, for example, based on the lighting device 10 according to the above-described embodiment, the lighting device 10 may include a filter (purple light cut filter) that reduces the transmittance of light in the purple light region and transmits light in the blue light region, green light region, and red light region on the surface of the translucent substrate 13.

[0121] In the above-described embodiment, for example, an example in which the first emission spectrum described above is realized by adjusting the content and selecting materials for each of the first phosphor 62a, the second phosphor 62b, and the third phosphor 62c has been described, but the present invention is not limited thereto. For example, the light-emitting device 1 may have a configuration in which a plurality of types of light-emitting elements and a filter (also referred to as a first reduction filter) that reduces the transmittance of light in the yellow light region and the orange light region and transmits light in the blue light region, the green light region, and the red light region are combined, and emit first light having the first emission spectrum described above. The plurality of types of light-emitting elements may include, for example, a light-emitting element that emits light having a spectrum with a peak in the blue light region, a light-emitting element that emits light having a spectrum with a peak in the green light region, and a light-emitting element that emits light having a spectrum with a peak in the red light region. For the first reduction filter, for example, a dielectric multilayer film may be applied. For the dielectric multilayer film, the transmittance of a specific wavelength region can be reduced by appropriately setting the thicknesses of the plurality of dielectric layers constituting the dielectric multilayer film.

[0122] In the above-described embodiment, an example in which the lighting device 10 includes a plurality of light-emitting devices 1 that each emit the first light and emits third light having the second emission spectrum described above has been described, but the present invention is not limited thereto.

[0123] For example, based on the lighting device 10 according to the above-described embodiment, by using a plurality of light-emitting devices 1 that emit lights with mutually different spectra, the lighting device 10 may emit a third light having the second emission spectrum described above. Here, for example, by appropriately adjusting the number and types of the plurality of light-emitting devices, the lighting device 10 may emit a third light having the second emission spectrum described above. More specifically, for example, the lighting device 10 may include, as the plurality of light-emitting devices, a first light-emitting device that emits light having a spectrum with peaks of light intensity in the purple light region and the blue light region, a second light-emitting device that emits light having a spectrum with peaks of light intensity in the purple light region and the green light region, and a third light-emitting device that emits light having a spectrum with peaks of light intensity in the purple light region and the red light region. The first light-emitting device may have, for example, a configuration in which each of the plurality of phosphors 62 is a blue phosphor, based on the light-emitting device 1 according to the above-described embodiment. The second light-emitting device may have, for example, a configuration in which each of the plurality of phosphors 62 is a green phosphor, based on the light-emitting device 1 according to the above-described embodiment. The third light-emitting device may have, for example, a configuration in which each of the plurality of phosphors 62 is a red phosphor, based on the light-emitting device 1 according to the above-described embodiment. For example, the lighting device 10 may include, as the plurality of light-emitting devices, a light-emitting device having a light-emitting element that emits excitation light having a spectrum with a peak of light intensity in the purple light region and that emits light having a spectrum with a peak of light intensity in the purple light region, and a light-emitting device having a light-emitting element that emits excitation light having a spectrum with a peak of light intensity in the blue light region and that emits light having a spectrum with a peak of light intensity in the blue light region.

[0124] Further, for example, the lighting device 10 may emit third light having the second emission spectrum described above by combining a plurality of light-emitting devices and a filter (first reduction filter) whose transmittance of light in the yellow light region and the orange light region is reduced and which transmits light in the blue light region, the green light region, and the red light region. Here, for example, each of the plurality of light-emitting devices may emit light having a spectrum having a peak in light intensity in each of the blue light region, the green light region, and the red light region, or the plurality of light-emitting devices as a whole may emit light having a spectrum having a peak in light intensity in each of the blue light region, the green light region, and the red light region. For example, the plurality of light-emitting devices may include a first light-emitting device that emits light having a spectrum having a peak in light intensity in each of the violet light region and the blue light region, a second light-emitting device that emits light having a spectrum having a peak in light intensity in each of the violet light region and the green light region, and a third light-emitting device that emits light having a spectrum having a peak in light intensity in each of the violet light region and the red light region. The first light-emitting device may have a configuration in which each of the plurality of phosphors 62 is a blue phosphor, for example, based on the light-emitting device 1 according to the above-described embodiment. The second light-emitting device may have a configuration in which each of the plurality of phosphors 62 is a green phosphor, for example, based on the light-emitting device 1 according to the above-described embodiment. The third light-emitting device may have a configuration in which each of the plurality of phosphors 62 is a red phosphor, for example, based on the light-emitting device 1 according to the above-described embodiment.

[0125] In the above-described embodiment, for example, when the fourth peak wavelength is 405 nm, the growth of cyanobacteria in the water tank can be reduced by the illumination light of the lighting device to which the light-emitting device 1 is applied. Further, for example, when the fourth peak wavelength of the first emission spectrum is 405 nm, the growth of cyanobacteria in the water tank can be reduced more by the illumination light of the lighting device to which the light-emitting device 1 is applied than when the first emission spectrum does not have the fourth peak P4.

[0126] In the above-described embodiment, for example, when the eighth peak wavelength is 405 nm, the growth of cyanobacteria in the water tank can be reduced by the illumination light of the illumination device 10. Further, for example, when the eighth peak wavelength of the second emission spectrum is 405 nm, the growth of cyanobacteria in the water tank can be reduced more effectively by the illumination light of the illumination device 10 than when the second emission spectrum does not have the eighth peak P8.

[0127] In the above-described embodiment, for example, the light-emitting device 1 includes one light-emitting element 3, but is not limited thereto. The light-emitting device 1 may include, for example, two or more light-emitting elements 3. In this case, the two or more light-emitting elements 3 may include a first light-emitting element 3 and a second light-emitting element 3. The intensity of the excitation light emitted by the first light-emitting element 3 and the intensity of the excitation light emitted by the second light-emitting element 3 may be independently controlled or may be controlled in association with each other. In the light-emitting device 1, the excitation light from the first light-emitting element 3 may be incident on the first portion of the wavelength conversion member 6, and the excitation light from the second light-emitting element 3 may be incident on another second portion different from the first portion of the wavelength conversion member 6. Further, the light-emitting device 1 may include, as two or more light-emitting elements 3, a light-emitting element that emits excitation light having a peak in the light intensity in the violet light region and a light-emitting element that emits excitation light having a peak in the light intensity in the blue light region.

[0128] In the above-described embodiment, for example, an example of the lighting device 10 including a plurality of light-emitting devices 1 arranged along a virtual straight line has been described, but the present invention is not limited thereto. For example, the lighting device 10 may be a lighting device including a plurality of light-emitting devices 1 arranged in a grid pattern or a staggered pattern. In other words, for example, the lighting device 10 may be a surface-emitting lighting device. Further, for example, the wiring board 12 had a plate-like shape having an elongated rectangular front and back surfaces, but the present invention is not limited thereto. The wiring board 12 may have, for example, a plate-like shape having square front and back surfaces such as a square shape, or may have a plate-like shape having front and back surfaces other than square shapes such as a circular shape or an elliptical shape. Further, for example, the housing 11 had an elongated rectangular parallelepiped shape, but the present invention is not limited thereto. The housing 11 may have, for example, a bottom portion 21a and a lid portion 22 having a shape adapted to the shape of the wiring board 12. Further, for example, the translucent substrate 13 had a plate-like shape having an elongated rectangular front and back surfaces, but the present invention is not limited thereto. The translucent substrate 13 may have, for example, a shape adapted to the shape of the bottom portion 21a of the housing 11 or the like.

[0129] In the above-described embodiment, for example, a configuration of a lighting module including a plurality of lighting devices 10 may be adopted. This lighting module may have, for example, a configuration in which a plurality of lighting devices 10 are arranged on one substrate, or may have a configuration in which a plurality of lighting devices 10 are connected by a connecting rod or a framework or the like.

[0130] In the above-described embodiment, for example, when the lighting device 10 is used for lighting aquatic organisms in various aquariums or the like, the lighting device 10 may include a sealing material or the like disposed at a predetermined position such as between the housing 11 and the translucent substrate 13. Further, for example, the lighting device 10 may include a moisture absorbent or the like disposed in the housing 11.

[0131] In the above-described embodiment, for example, as the package of the LED applied to the light-emitting device 1, a chip scale package (CSP) having the same size as or a size close to that of the LED chip may be adopted.

[0132] As described above, the light-emitting device and the lighting device have been described in detail. However, the above description is illustrative in all aspects and this disclosure is not limited thereto. Also, the various examples described above can be applied in combination as long as they do not conflict with each other. And countless examples that are not illustrated can be assumed without departing from the scope of this disclosure.

[0133] This disclosure includes the following content.

[0134] In one embodiment, (1) the light-emitting device emits first light of a first emission spectrum having a first peak of light intensity in a wavelength range of 430 nm to 500 nm, a second peak of light intensity in a wavelength range of 500 nm to 565 nm, and a third peak of light intensity in a wavelength range of 620 nm to 750 nm, and the first emission spectrum has a first minimum value of light intensity that is less than or equal to half of the light intensity of each of the second peak and the third peak in a wavelength range of 565 nm to 620 nm. In the first emission spectrum, when the maximum light intensity among the first peak, the second peak, and the third peak is set to 1, the light intensity of each of the first peak, the second peak, and the third peak is 0.6 or more.

[0135] (2) The light-emitting device according to (1) above includes a light-emitting element that emits second light having a peak in the wavelength range of 360 nm to 430 nm, a first phosphor that converts the second light into light having a peak in the wavelength range of 430 nm to 500 nm, a second phosphor that converts the second light into light having a peak in the wavelength range of 500 nm to 565 nm, and a third phosphor that converts the second light into light having a peak in the wavelength range of 620 nm to 750 nm. The first emission spectrum may include a fourth peak in the light intensity in the wavelength range of 360 nm to 430 nm by including a part of the second light emitted from the light-emitting element.

[0136] (3) In the light-emitting device according to (1) or (2) above, the color temperature of the first light may be from 4500 K to 12000 K.

[0137] (4) In any one of the light-emitting devices according to (1) to (3) above, in the first emission spectrum, the light intensity of the third peak may be 2.5 times or more that of the first minimum value.

[0138] (5) In any one of the light-emitting devices according to (1) to (3) above, in the first emission spectrum, the light intensity of the first peak may be greater than the light intensity of either the second peak or the third peak.

[0139] (6) In any one of the light-emitting devices according to (1) to (4) above, in the first emission spectrum, when the maximum value of the light intensity in the wavelength range of 350 nm to 800 nm is set to 1, the light intensity of the first peak, the light intensity of the second peak, and the light intensity of the third peak may each be 0.8 or more.

[0140] (7) In any one of the light-emitting devices according to (1) to (6) above, in the first light, the light energy in the wavelength range of 565 nm to 620 nm may be 15% or less of the light energy in the wavelength range of 350 nm to 800 nm.

[0141] (8) In any one of the light-emitting devices (1) to (7) above, in the first light, the light energy in the wavelength range of 565 nm to 620 nm may be 5% or more of the light energy in the wavelength range of 350 nm to 800 nm.

[0142] (9) Any one of the light-emitting devices (1) to (8) above may be a light-emitting device used for displaying aquatic organisms.

[0143] (10) Any one of the light-emitting devices (1) to (8) above may be a light-emitting device used for growing aquatic organisms.

[0144] (11) Any one of the light-emitting devices (1) to (8) above may be a light-emitting device used for reducing the growth of cyanobacteria.

[0145] In one embodiment, (12) The lighting device includes a plurality of any one of the light-emitting devices (1) to (11) above.

[0146] In one embodiment, (13) The lighting device emits the third light of the second emission spectrum having a fifth peak of the light intensity in the wavelength range of 430 nm to 500 nm, a sixth peak of the light intensity in the wavelength range of 500 nm to 565 nm, and a seventh peak of the light intensity in the wavelength range of 620 nm to 750 nm. The second emission spectrum has a second minimum value of the light intensity that is less than or equal to half of the light intensity of each of the sixth peak and the seventh peak in the wavelength range of 565 nm to 620 nm. In the second emission spectrum, when the maximum light intensity among the fifth peak, the sixth peak, and the seventh peak is set to 1, the light intensity of each of the fifth peak, the sixth peak, and the seventh peak is 0.6 or more.

[0147] (14) In the lighting device (13) above, the color temperature of the third light may be from 4500 K to 12000 K.

[0148] In the lighting device of (13) or (14) above, in the second emission spectrum, the light intensity of the seventh peak may be 2.5 times or more that of the second minimum value.

[0149] (16) In the lighting device of (13) or (14) above, in the second emission spectrum, the light intensity of the fifth peak may be greater than the light intensity of either the sixth peak or the seventh peak.

[0150] (17) In any one of the lighting devices of (13) to (15) above, in the second emission spectrum, when the maximum value of the light intensity in the wavelength range from 350 nm to 800 nm is taken as 1, the light intensity of each of the fifth peak, the sixth peak, and the seventh peak may be 0.8 or more.

[0151] (18) In any one of the lighting devices of (13) to (17) above, in the third light, the light energy in the wavelength range from 565 nm to 620 nm may be 15% or less of the light energy in the wavelength range from 350 nm to 800 nm.

[0152] (19) In any one of the lighting devices of (13) to (18) above, in the third light, the light energy in the wavelength range from 565 nm to 620 nm may be 5% or more of the light energy in the wavelength range from 350 nm to 800 nm.

[0153] (20) Any one of the lighting devices of (13) to (19) above may be a lighting device used for displaying aquatic organisms.

[0154] (21) Any one of the lighting devices of (13) to (19) above may be a lighting device used for growing aquatic organisms.

[0155] (22) Any one of the lighting devices of (13) to (19) above may be a lighting device used for reducing the growth of cyanobacteria.

Description of Symbols

[0156] 1 Light-emitting device 10 Lighting device 3 Light-emitting element 62 Phosphor 62a First phosphor 62b Second phosphor 62c Third phosphor P1 First peak P2 Second peak P3 Third peak P4 Fourth peak P5 Fifth peak P6 Sixth peak P7 Seventh peak P8 Eighth peak

Claims

1. emitting first light of a first emission spectrum having a first peak of light intensity in a wavelength region of 430 nm to 500 nm, a second peak of light intensity in a wavelength region of 500 nm to 565 nm, and a third peak of light intensity in a wavelength region of 620 nm to 750 nm, and the first emission spectrum having a first minimum value of light intensity that is equal to or less than half of the light intensity of each of the second peak and the third peak in a wavelength region of 565 nm to 620 nm, a light-emitting device, wherein, in the first emission spectrum, when the maximum light intensity among the first peak, the second peak, and the third peak is set to 1, the light intensity of each of the first peak, the second peak, and the third peak is 0.6 or more.

2. The light-emitting device according to claim 1, comprising a light-emitting element that emits second light having a peak of light intensity in a wavelength region of 360 nm to 430 nm, a first phosphor that converts the second light into light having a peak of light intensity in a wavelength region of 430 nm to 500 nm, a second phosphor that converts the second light into light having a peak of light intensity in a wavelength region of 500 nm to 565 nm, and a third phosphor that converts the second light into light having a peak of light intensity in a wavelength region of 620 nm to 750 nm, wherein the first emission spectrum includes a part of the second light emitted from the light-emitting element and thus has a fourth peak of light intensity in a wavelength region of 360 nm to 430 nm.

3. The light-emitting device according to claim 1 or claim 2, wherein a color temperature of the first light is from 4500 K to 12000 K.

4. The light-emitting device according to claim 1 or claim 2, wherein, in the first emission spectrum, the light intensity of the third peak is 2.5 times or more the first minimum value.

5. The light-emitting device according to claim 1 or claim 2, wherein, in the first emission spectrum, the light intensity of the first peak is greater than the light intensity of each of the second peak and the third peak.

6. The light-emitting device according to claim 1 or claim 2, wherein, in the first emission spectrum, when the maximum value of the light intensity in a wavelength region of 350 nm to 800 nm is set to 1, the light intensity of each of the first peak, the second peak, and the third peak is 0.8 or more.

7. The light-emitting device according to claim 1 or claim 2, wherein, in the first light, the light energy in the wavelength range of 565 nm to 620 nm is 15% or less of the light energy in the wavelength range of 350 nm to 800 nm.

8. The light-emitting device according to claim 1 or claim 2, wherein, in the first light, the light energy in the wavelength range of 565 nm to 620 nm is 5% or more of the light energy in the wavelength range of 350 nm to 800 nm.

9. The light-emitting device according to claim 1 or claim 2, which is used for displaying aquatic organisms.

10. The light-emitting device according to claim 1 or claim 2, which is used for growing aquatic organisms.

11. The light-emitting device according to claim 1 or claim 2, which is used for reducing the growth of cyanobacteria.

12. A lighting device comprising a plurality of the light-emitting devices according to claim 1 or claim 2.

13. emitting third light having a fifth peak in the light intensity in the wavelength range of 430 nm to 500 nm, a sixth peak in the light intensity in the wavelength range of 500 nm to 565 nm, and a seventh peak in the light intensity in the wavelength range of 620 nm to 750 nm, and wherein the second emission spectrum has a second minimum value of light intensity that is half or less of the light intensity of each of the sixth peak and the seventh peak in the wavelength range of 565 nm to 620 nm, and in the second emission spectrum, when the maximum light intensity among the fifth peak, the sixth peak, and the seventh peak is set to 1, the light intensity of each of the fifth peak, the sixth peak, and the seventh peak is 0.6 or more.

14. The lighting device according to claim 13, wherein the color temperature of the third light is from 4500 K to 12000 K.

15. The lighting device according to claim 13 or claim 14, wherein in the second emission spectrum, the light intensity of the seventh peak is 2.5 times or more the second minimum value.

16. The lighting device according to claim 13 or claim 14, wherein in the second emission spectrum, the light intensity of the fifth peak is greater than the light intensity of either the sixth peak or the seventh peak.

17. The lighting device according to claim 13 or claim 14, wherein in the second emission spectrum, when the maximum value of the light intensity in the wavelength range from 350 nm to 800 nm is set to 1, the light intensity of the fifth peak, the light intensity of the sixth peak, and the light intensity of the seventh peak are each 0.8 or more.

18. The lighting device according to claim 13 or claim 14, wherein in the third light, the light energy in the wavelength range from 565 nm to 620 nm is 15% or less of the light energy in the wavelength range from 350 nm to 800 nm.

19. The lighting device according to claim 13 or claim 14, wherein in the third light, the light energy in the wavelength range from 565 nm to 620 nm is 5% or more of the light energy in the wavelength range from 350 nm to 800 nm.

20. The lighting device according to claim 13 or claim 14, wherein it is a lighting device used for displaying aquatic organisms.

21. The lighting device according to claim 13 or claim 14, wherein it is a lighting device used for growing aquatic organisms.

22. The lighting device according to claim 13 or claim 14, wherein it is a lighting device used for reducing the growth of cyanobacteria.

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