JP7720567B2 - Light source module and lighting fixture - Google Patents

Description

The present invention relates to a light source module and a lighting fixture.

Patent Document 1 discloses a light source module equipped with a blue-violet LED (Light Emitting Diode) and a white LED.

Special table 2019-525413 publication

Recently, it has been reported that purple light is effective in suppressing myopia in humans. However, the prior art does not disclose the configuration of a light source module that is appropriate when using light containing purple components to illuminate people.

The present invention aims to provide a light source module and lighting fixture that can effectively emit output light containing a violet component.

A light source module according to one aspect of the present invention is a light source module that emits output light, and includes a first light-emitting element, at least one purple light-emitting unit that emits first light, a second light-emitting element, and a phosphor that emits light when excited by light from the second light-emitting element, and at least one white light-emitting unit that emits white second light, wherein the output light includes the first light and the second light, the emission peak wavelength of the first light-emitting element is shorter than the emission peak wavelength of the second light-emitting element and is between 350 nm and 410 nm, and the excitation spectrum of the phosphor has a minimum value in the wavelength range of 350 nm and 410 nm in which the first light-emitting element has an emission intensity.

A lighting fixture according to one aspect of the present invention comprises the above-described light source module and a lighting circuit that supplies power to the light source module for lighting the light source module.

The present invention provides a light source module and lighting fixture that can effectively emit output light containing a violet component.

FIG. 1 is a perspective view showing an example of the appearance of a lighting fixture including a light source module according to a first embodiment. FIG. 2 is a block diagram showing the configuration of the lighting fixture according to the first embodiment. FIG. 3 is a plan view showing the light source module according to the first embodiment. FIG. 4 is a cross-sectional view showing a part of the light source module according to the first embodiment. FIG. 5 is a diagram illustrating an example of the spectrum of the first light emitted by the first light-emitting unit according to the first embodiment. FIG. 6 is a diagram illustrating an example of the spectrum of the second light emitted by the second light-emitting unit according to the first embodiment. FIG. 7 is a diagram showing an example of an excitation spectrum of a phosphor included in the second light-emitting unit according to the first embodiment. FIG. 8 is a diagram illustrating an example of the spectrum of the output light emitted by the light source module according to the first embodiment. FIG. 9 is a plan view showing a light source module according to a modification of the first embodiment. FIG. 10 is a block diagram showing the configuration of a lighting fixture according to the second embodiment. FIG. 11 is a diagram showing an example of the spectrum of output light emitted by the light source module according to the second embodiment and the spectrum of sunlight having the same correlated color temperature as the output light. FIG. 12 is a block diagram showing the configuration of a lighting fixture according to a modification of the second embodiment. FIG. 13 is an xy chromaticity diagram in the CIE 1931 color space for illustrating an example of changes in the correlated color temperature of output light from a lighting device according to a modification of the second embodiment.

The following describes in detail light source modules and lighting fixtures according to embodiments of the present invention, using the drawings. Note that each of the embodiments described below represents a specific example of the present invention. Therefore, the numerical values, shapes, materials, components, component arrangement and connection forms, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present invention. Of the components in the following embodiments, components not recited in the independent claims will be described as optional components.

Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scales of the figures do not necessarily match. Furthermore, in each figure, substantially identical components are assigned the same reference numerals, and redundant explanations are omitted or simplified.

In addition, in this specification, terms indicating the relationship between elements, terms indicating the shape of elements, and numerical ranges are not expressions that express only the strict meaning, but also expressions that include a substantially equivalent range, for example, a difference of about a few percent.

In addition, in this specification, ordinal numbers such as "first" and "second" do not refer to the number or order of components, unless otherwise specified, but are used to avoid confusion and distinguish between components of the same type.

In addition, in this specification, the numerical value of color deviation Duv is the numerical value of Duv, which is an expression of color deviation from the blackbody radiation locus defined by JIS Z8725, i.e., 1000 times the numerical value of duv. In other words, in this specification, the numerical value of color deviation Duv is 1000 times the numerical value of duv, in accordance with JIS Z8725, unless otherwise specified.

(Embodiment 1)
[composition]
First, the configuration of a light source module and a lighting fixture according to the first embodiment will be described with reference to FIGS. 1 to 4. FIG.

Figure 1 is a perspective view showing an example of the appearance of a lighting fixture 100 equipped with a light source module 50 according to this embodiment. Figure 2 is a block diagram showing the configuration of the lighting fixture 100 according to this embodiment. Figure 3 is a plan view showing a light source module 50 according to this embodiment. Figure 4 is a cross-sectional view showing a portion of a light source module 50 according to this embodiment. Figure 4 shows a cross-section taken along line IV-IV in Figure 3.

The lighting fixture 100 shown in FIG. 1 is, for example, a stand lamp. As shown in FIG. 2, the lighting fixture 100 includes a light source module 50 and a lighting circuit 70. The lighting fixture 100 also includes, for example, a head housing that houses the light source module 50, an arm that supports the head, and a main body to which the arm is attached. The lighting fixture 100 receives power from a power supply such as a commercial power source, and irradiates the light emitted by the light source module 50 using that power as illumination. The lighting fixture 100 is not particularly limited as long as it is a lighting fixture used for illumination, and may be a ceiling light, base light, spotlight, downlight, pendant light, wall light, or floor light, for example. The lighting fixture 100 is a residential lighting fixture installed in, for example, a child's room, bedroom, living room, or study, but may also be a lighting fixture used in offices, stores, commercial facilities, factories, etc.

The light source module 50 emits output light used for illumination. The light color of the output light is, for example, white. As shown in FIG. 3, the light source module 50 includes a substrate 1, a first light-emitting unit 10, and a second light-emitting unit 20. In this embodiment, the light source module 50 includes a plurality of first light-emitting units 10 and a plurality of second light-emitting units 20. The first light-emitting unit 10 is an example of a purple light-emitting unit, and the second light-emitting unit 20 is an example of a white light-emitting unit. Note that in FIG. 3, the first light-emitting unit 10 is marked with a dotted pattern; however, this is intended to distinguish the first light-emitting unit 10 from the second light-emitting unit 20, and does not mean that the first light-emitting unit 10 is marked with a dotted pattern.

The first light-emitting unit 10 and the second light-emitting unit 20 are each a surface mount device (SMD) light-emitting module.

The first light-emitting unit 10 emits a first light. The second light-emitting unit 20 emits a second light. The output light emitted by the light source module 50 includes the first light emitted by all of the first light-emitting units 10 included in the light source module 50 and the second light emitted by all of the second light-emitting units 20 included in the light source module 50. In other words, the output light of the light source module 50 is a mixture of the first light and the second light. In the output light, the total radiant energy of the second light emitted by all of the second light-emitting units 20 is greater than, for example, the total radiant energy of the first light emitted by all of the first light-emitting units 10.

The multiple first light-emitting units 10 and the multiple second light-emitting units 20 are arranged, for example, spaced apart from one another on the substrate 1. In the example shown in FIG. 3, the multiple first light-emitting units 10 and the multiple second light-emitting units 20 are arranged in a regular line at equal intervals. The number of second light-emitting units 20 is, for example, greater than the number of first light-emitting units 10. Note that the number and arrangement of the first light-emitting units 10 and second light-emitting units 20 are not particularly limited. The first light-emitting units 10 and second light-emitting units 20 may be arranged, for example, in two or more rows, in a ring shape, or at lattice points in a predetermined lattice shape. Furthermore, the number of at least one of the first light-emitting units 10 and second light-emitting units 20 may be one. The arrangement of the first light-emitting units 10 and second light-emitting units 20 is determined, for example, by creating several arrangement patterns and evaluating the light radiation characteristics, etc. of each arrangement pattern to select the best arrangement pattern.

The multiple first light-emitting units 10 and the multiple second light-emitting units 20 are mounted on the substrate 1, for example, so that the same amount of current flows through them. Note that the multiple first light-emitting units 10 and the multiple second light-emitting units 20 may also be mounted on the substrate 1 so that individual currents can flow independently.

Substrate 1 is a mounting substrate for mounting the first light-emitting unit 10 and the second light-emitting unit 20. Substrate 1 is provided with metal wiring (not shown) for supplying power to the first light-emitting unit 10 and the second light-emitting unit 20. Substrate 1 is, for example, a ceramic substrate made of ceramic, a resin substrate made of resin, or an insulating substrate such as a glass substrate. Alternatively, substrate 1 may be a metal-based substrate (metal substrate) in which an insulating film is coated on a metal plate.

As shown in FIG. 4, the first light-emitting unit 10 has a first light-emitting element 11, a sealing member 15, and a package 17. The first light-emitting unit 10 does not contain, for example, a phosphor, and emits light emitted by the first light-emitting element 11 as is as the first light. The first light is light containing a violet component that has intensity in the wavelength range of the violet component, for example, violet light. By using the first light as light containing a violet component, for example, the output light can be used for lighting to achieve the effect of suppressing myopia in humans. Note that in this specification, the wavelength range of the violet component can be considered to be, for example, a wavelength range of 350 nm to 410 nm.

The first light-emitting element 11 is, for example, an LED chip, and is disposed in a recess in the package 17. The emission peak wavelength of the first light-emitting element 11 is, for example, 350 nm or more and 410 nm or less, and may be 360 nm or more and 400 nm or less. Furthermore, the emission peak wavelength of the first light-emitting element 11 is shorter than the emission peak wavelength of the second light-emitting element 21.

The sealing member 15 is a translucent resin material that seals the first light-emitting element 11. There are no particular limitations on the translucent resin material, as long as it is a material that transmits the light emitted by the first light-emitting element 11. Examples of translucent resin materials that can be used include silicone resin, epoxy resin, and urea resin.

The package 17 is, for example, a container molded into a predetermined shape using a resin material.

As shown in FIG. 4, the second light-emitting unit 20 includes a second light-emitting element 21, a phosphor 22, a sealing member 25, and a package 27. The second light-emitting unit 20 emits white second light, which is a mixture of light emitted by the second light-emitting element 21 (specifically, light emitted by the second light-emitting element 21 that is not absorbed by the phosphor 22) and light emitted by the phosphor 22. Note that in this specification, white light refers to a lighting light color that falls within the range of daylight (symbol D), daylight white (symbol N), white (symbol W), warm white (symbol WW), and incandescent white (symbol L), or along the blackbody radiation locus or synthetic daylight locus with a correlated color temperature higher or lower than that range. It does not refer to the narrow range of white (symbol W) in the chromaticity classification of light colors. The color deviation Duv of the second light and the output light is, for example, between -10 and +10.

The second light-emitting element 21 is, for example, an LED chip, and is disposed in a recess in the package 27. The emission peak wavelength of the second light-emitting element 21 is, for example, 410 nm or more and 500 nm or less, and may be 420 nm or more and 470 nm or less. The second light-emitting element 21 emits, for example, blue light.

The phosphor 22 is excited by a portion of the light emitted by the second light-emitting element 21 and emits light with a longer wavelength than the light emitted by the second light-emitting element 21. The phosphor 22 emits, for example, green light with an emission peak wavelength of 500 nm or more and 570 nm or less. The phosphor 22 is dispersed in the sealing member 25. The phosphor 22 is, for example, an yttrium aluminum garnet (YAG) phosphor or a lutetium aluminum garnet (LuAG) phosphor. Using these phosphors makes it easy to adjust the wavelength at which the excitation spectrum of the phosphor 22 exhibits a minimum value, as described below. For example, adjusting the compositional elements of the phosphor 22 changes the band gap of the phosphor 22, thereby enabling adjustment of the excitation spectrum of the phosphor 22. Note that the color of the light emitted by the phosphor 22 is not limited to green and may be a color other than green, such as yellow or red. The second light-emitting unit 20 may further include another phosphor with an emission peak wavelength different from that of the phosphor 22 to adjust the light color of the second light.

The sealing member 25 is a translucent resin material that seals the second light-emitting element 21. There are no particular limitations on the translucent resin material, as long as it transmits the light emitted by the second light-emitting element 21 and the phosphor 22. Examples of translucent resin materials that can be used include silicone resin, epoxy resin, and urea resin.

The package 27 is, for example, a container molded into a predetermined shape using a resin material.

The second light emitted by the second light-emitting unit 20 can be adjusted to the desired light color by adjusting at least one of the output characteristics of the second light-emitting element 21 and the type and amount of phosphor 22.

The first light-emitting unit 10 and the second light-emitting unit 20 may not have the package 17 and the package 27, respectively, and the first light-emitting element 11 and the second light-emitting element 21 may be mounted directly on the substrate 1. In other words, the light source module 50 may be a COB (chip on board) type module in which the first light-emitting element 11 and the second light-emitting element 21 are mounted directly on the substrate 1.

The lighting circuit 70 is a circuit that lights up the light source module 50 by supplying power to the light source module 50. The lighting circuit 70, for example, supplies a predetermined amount of power (DC current) to each of the first light-emitting unit 10 and the second light-emitting unit 20. The lighting circuit 70 includes, for example, a circuit that converts AC current supplied from a commercial power source into DC current.

The lighting fixture 100 may further include a control unit (control circuit) that adjusts the brightness and color of the light output from the light source module 50. The control unit, for example, controls the power supplied to the light source module 50 by the lighting circuit 70. The lighting fixture 100 may also include an operation reception unit, such as a switch or input panel, that receives operations on the lighting fixture 100, and a communication module for remote operation.

[Spectra of First Light, Second Light, and Output Light, and Excitation Spectrum of Phosphor]
Next, the spectra of the first light, the second light, and the output light, as well as the excitation spectrum of the phosphor 22, will be described with reference to FIGS.

Figure 5 shows an example of the spectrum of the first light emitted by the first light emitter 10 according to the present embodiment. Figure 6 shows an example of the spectrum of the second light emitted by the second light emitter 20 according to the present embodiment. Figure 7 shows an example of the excitation spectrum of the phosphor 22 included in the second light emitter 20 according to the present embodiment. Figure 8 shows an example of the spectrum of the output light emitted by the light source module 50 according to the present embodiment. In Figures 5 to 8, the horizontal axis represents wavelength (unit: nm). In Figures 5, 6, and 8, the vertical axis represents emission intensity normalized with the maximum value set to 1. That is, Figures 5, 6, and 8 show spectra normalized by radiant flux (unit: W/nm) for each wavelength. In Figure 7, the vertical axis represents excitation intensity normalized with the maximum value set to 1. In general, the excitation spectrum of a phosphor is approximately the same as its absorption spectrum.

As shown in FIG. 5, the spectrum of the first light includes the emission peak of the light emitted by the first light-emitting element 11. In the present embodiment, the spectrum of the first light is, for example, the same as the spectrum of the light emitted by the first light-emitting element 11, and the spectrum shown in FIG. 5 can also be said to be the spectrum of the light emitted by the first light-emitting element 11. In the example shown in FIG. 5, the wavelength of the emission peak of the first light-emitting element 11 is approximately 380 nm, and the half-width of this emission peak is approximately 10 nm. For example, the entire emission intensity of the light emitted by the first light-emitting element 11, i.e., the first light, falls within the wavelength range of the violet component.

The first light may have an emission intensity or emission peak outside the wavelength range of the violet component (e.g., on the longer wavelength side than the violet component) due to the first light-emitting unit 10 including a phosphor, for example. When the first light has an emission intensity or emission peak outside the wavelength range of the violet component, the maximum emission intensity or the emission intensity at the emission peak is, for example, half or less of the emission intensity of the emission peak of the light emitted by the first light-emitting element 11. Furthermore, when the first light has an emission intensity or emission peak outside the wavelength range of the violet component, for example, the radiant flux of the first light in the wavelength range of the violet component may be one or more times, or even two or more times, the radiant flux of the first light outside the wavelength range of the violet component.

As shown in FIG. 6, the spectrum of the second light includes an emission peak of the light emitted by the second light-emitting element 21 and a broad emission peak of the light emitted by the phosphor 22. FIG. 6 shows the spectrum of the second light when the correlated color temperature is 5000 K. In the example shown in FIG. 6, the wavelength of the emission peak of the second light-emitting element 21 is approximately 450 nm, and the half-width of this emission peak is approximately 20 nm. Furthermore, the wavelength of the emission peak of the light emitted by the phosphor 22 is approximately 580 nm.

As shown in FIG. 7, the excitation spectrum of the phosphor 22 has a minimum value in the wavelength range of 350 nm to 410 nm inclusive, where the first light-emitting element 11 has an emission intensity. For example, if a phosphor 22 that emits green light is used, the excitation intensity of the phosphor 22 tends to be small in the wavelength range of 350 nm to 410 nm inclusive, where the first light-emitting element 11 has an emission intensity. Also, the excitation spectrum of the phosphor 22 may have a minimum value in the wavelength range of 360 nm to 400 nm inclusive, where the first light-emitting element 11 has an emission intensity.

Furthermore, the excitation spectrum of phosphor 22 has a minimum value, for example, within the range of the half-width of the emission peak of the first light-emitting element 11. In the example shown in FIG. 7, the excitation spectrum of phosphor 22 has a minimum value of excitation intensity at approximately 380 nm. Therefore, in the examples shown in FIGS. 5 and 7, the wavelength of the emission peak of the first light-emitting element 11 and the wavelength at which the excitation spectrum of phosphor 22 shows a minimum value match. Note that if the second light-emitting section 20 includes another phosphor other than phosphor 22, the excitation spectrum of the other phosphor may also have a minimum value in the wavelength range in which the first light-emitting element 11 has an emission intensity.

In the example shown in FIG. 7, the excitation spectrum of the phosphor 22 has a maximum excitation intensity peak at a wavelength of approximately 430 nm. In the excitation spectrum of the phosphor 22, the excitation intensity at the emission peak wavelength of the first light-emitting element 11 (approximately 380 nm in this example) is, for example, less than half, and may even be less than one-third, of the excitation intensity at the emission peak wavelength of the second light-emitting element 21 (approximately 450 nm in this example). This makes it possible to suppress excitation of the phosphor 22 by the first light while increasing the luminous efficiency of the second light-emitting unit 20.

As such, in the light source module 50, the excitation spectrum of the phosphor 22 has a minimum value in the wavelength range in which the first light-emitting element 11 has an emission intensity. Therefore, even if a portion of the first light emitted from the first light-emitting unit 10 is incident on the second light-emitting unit 20 due to diffusion or other reasons, the incident first light is unlikely to excite the phosphor 22. This prevents the phosphor 22 from emitting light of an unintended wavelength due to the first light, and even when the light source module 50 includes the first light-emitting unit 10, changes in the color of the white second light emitted by the second light-emitting unit 20 are suppressed. In particular, since the light emitted by the phosphor 22 has a longer wavelength than the excitation light, the light emitted by the phosphor 22 excited by the first light has a wavelength longer than the wavelength of the first light, which increases human luminosity, and therefore has a significant impact on the light color perceived by humans. For example, human luminosity at 400 nm is 10 times that at 380 nm. Therefore, in the second light-emitting unit 20, excitation of the phosphor 22 by the first light is suppressed, thereby suppressing changes in light color from white, which is appropriate for illumination. Furthermore, because the first light is less likely to be absorbed by the phosphor 22, a decrease in the amount of the first light containing a violet component in the output light can be suppressed. Therefore, the light source module 50 can effectively emit output light containing a violet component that is used for illumination. Therefore, the output light of the light source module 50 can be used, for example, for illumination that has a myopia suppression effect.

As shown in FIG. 8 , the spectrum of the output light is a spectrum obtained by adding the spectrum of the first light and the spectrum of the second light at a predetermined ratio. The predetermined ratio is adjusted, for example, by the number of first light-emitting units 10 and second light-emitting units 20 included in the light source module 50 and the output power of each of the first light-emitting units 10 and second light-emitting units 20. The spectrum shown in FIG. 8 is the spectrum of the output light when the same current is passed through the first light-emitting units 10 and second light-emitting units 20 included in the light source module 50. The output light has the highest emission intensity, for example, at the emission peak wavelength of the first light-emitting element 11 (approximately 380 nm in this example). Because light with a purple wavelength has low luminosity, even if the emission intensity of the emission peak wavelength of the first light-emitting element 11 is high, the impact on the light color perceived by humans is small. Therefore, by increasing the purple component in the output light, the myopia suppression effect can be improved.

[Effects, etc.]
As described above, the light source module 50 according to the present embodiment is a light source module 50 that emits output light and includes a first light-emitting unit 10 that emits a first light and a second light-emitting unit 20 that emits a white second light. The first light-emitting unit 10 includes a first light-emitting element 11. The second light-emitting unit 20 includes a second light-emitting element 21 and a phosphor 22 that emits light upon being excited by light from the second light-emitting element 21. The output light includes the first light and the second light. The emission peak wavelength of the first light-emitting element 11 is shorter than the emission peak wavelength of the second light-emitting element 21 and is not less than 350 nm and not more than 410 nm. The excitation spectrum of the phosphor 22 has a minimum value in the wavelength range of not less than 350 nm and not more than 410 nm, in which the first light-emitting element 11 has an emission intensity.

As a result, even if a portion of the first light containing a violet component emitted from the first light-emitting unit 10 enters the second light-emitting unit 20 due to diffusion or the like, the incident first light is less likely to excite the phosphor 22. This prevents the phosphor 22 from emitting light of an unintended wavelength due to the first light, and even when the light source module 50 includes the first light-emitting unit 10, changes in the color of the white second light emitted by the second light-emitting unit 20 are suppressed. In other words, by suppressing excitation of the phosphor 22 by the first light in the second light-emitting unit 20, changes in light color from the white color appropriate for illumination can be suppressed. Furthermore, because the first light is less likely to be absorbed by the phosphor 22, a decrease in the amount of the first light containing a violet component in the output light can be suppressed. Therefore, the light source module 50 can effectively emit output light containing a violet component.

Furthermore, for example, the excitation spectrum of the phosphor 22 has a minimum value within the half-width range of the emission peak of the first light-emitting element 11.

This further suppresses excitation of the phosphor 22 by the first light in the second light-emitting section 20.

Furthermore, for example, in the excitation spectrum of the phosphor 22, the intensity at the emission peak wavelength of the first light-emitting element 11 is less than half the intensity at the emission peak wavelength of the second light-emitting element 21.

This increases the luminous efficiency of the second light-emitting unit 20 while suppressing excitation of the phosphor 22 by the first light.

Furthermore, for example, the output light of the light source module 50 has the highest emission intensity at the wavelength of the emission peak of the first light-emitting element 11.

This increases the purple component in the output light. As a result, for example, the effect of the output light on suppressing myopia in humans can be improved.

The lighting fixture 100 according to this embodiment also includes a light source module 50 and a lighting circuit 70 that supplies power to the light source module 50 to light the light source module 50.

This allows for the creation of a lighting fixture 100 that can effectively emit output light containing a purple component.

[Modification]
Next, a description will be given of a modification of embodiment 1. In the following description, differences from embodiment 1 will be mainly described, and descriptions of commonalities will be omitted or simplified.

Figure 9 is a plan view showing a light source module 50a according to this modification. As shown in Figure 9, the light source module 50a differs from the light source module 50 according to embodiment 1 in that the multiple first light-emitting units 10 and the multiple second light-emitting units 20 are not arranged at equal intervals. The light source module 50a can be used in the lighting fixture 100, for example, in place of the light source module 50.

The multiple first light-emitting units 10 include a first light-emitting unit 10a, which is one of the multiple first light-emitting units 10. The multiple second light-emitting units 20 include a second light-emitting unit 20a that is closest to the first light-emitting unit 10a among the multiple second light-emitting units 20, and a second light-emitting unit 20b that is closest to the second light-emitting unit 20a among the multiple second light-emitting units 20. The first light-emitting unit 10a is an example of a first purple light-emitting unit. The second light-emitting unit 20a is an example of a first white light-emitting unit. The second light-emitting unit 20b is an example of a second white light-emitting unit. The first light-emitting unit 10a, second light-emitting unit 20a, and second light-emitting unit 20b are, for example, arranged in a row in this order.

The distance W1 between the first light-emitting unit 10a and the second light-emitting unit 20a is longer than the distance W2 between the second light-emitting unit 20a and the second light-emitting unit 20b. This increases the distance W1 between the second light-emitting unit 20a and the first light-emitting unit 10a closest to the second light-emitting unit 20a, making it more difficult for the first light emitted by the first light-emitting unit 10a to enter the second light-emitting unit 20a. As a result, excitation of the phosphor 22 by the first light is further suppressed. This further suppresses changes in the color of the second light and decreases in the amount of the first light in the output light.

Furthermore, in the light source module 50a, for example, the distance to the first light-emitting unit 10 closest to each of the multiple second light-emitting units 20 is longer than the distance to the second light-emitting unit 20 other than itself that is closest to each of the multiple second light-emitting units 20.

As described above, in the light source module 50a according to this modified example, at least one first light-emitting unit 10 includes a first light-emitting unit 10a, and at least one second light-emitting unit 20 includes, of the second light-emitting units 20, a second light-emitting unit 20a that is closest to the first light-emitting unit 10a and a second light-emitting unit 20b that is closest to the second light-emitting unit 20a. The distance W1 between the first light-emitting unit 10a and the second light-emitting unit 20a is longer than the distance W2 between the second light-emitting unit 20a and the second light-emitting unit 20b.

This makes it difficult for the first light emitted by the first light-emitting unit 10a to enter the second light-emitting unit 20a, further preventing the first light from exciting the phosphor 22.

(Embodiment 2)
Next, a description will be given of a second embodiment. The following description will focus on the differences between the first embodiment and the modified version of the first embodiment, and the description of the commonalities will be omitted or simplified.

Figure 10 is a block diagram showing the configuration of lighting fixture 200 according to this embodiment. As shown in Figure 10, lighting fixture 200 differs from lighting fixture 100 according to embodiment 1 in that it includes light source module 250 instead of light source module 50.

Like light source module 50, light source module 250 has multiple light-emitting units including at least one first light-emitting unit 10 and at least one second light-emitting unit 20, but has a different spectrum of output light from light source module 50. The configuration of light source module 250 is the same as light source module 50, except that, for example, multiple light-emitting units are configured to emit output light with a different spectrum from that of light source module 50. The output light emitted by light source module 250 includes first light emitted by all first light-emitting units 10 provided in light source module 250 and second light emitted by all second light-emitting units 20 provided in light source module 250.

The light source module 250 has a different output light spectrum than the light source module 50, for example, because the number of first light-emitting units 10 and second light-emitting units 20 included is different from that of the light source module 50. The light source module 250 may also have a different output light spectrum than the light source module 50 because the light-emitting characteristics of at least one of the first light-emitting element 11, the second light-emitting element 21, and the phosphor 22 are different from those of the light source module 50.

Figure 11 shows an example of the spectrum of output light emitted by the light source module 250 according to this embodiment and the spectrum of sunlight having the same correlated color temperature as the output light. In Figure 11, the horizontal axis represents wavelength (unit: nm). In Figure 11, the vertical axis represents luminous intensity normalized with the maximum value set to 1. The spectra of the first light and second light and the excitation spectrum of the phosphor 22 are, for example, the spectra shown in Figures 5 to 7.

The spectrum of output light shown in Figure 11 is the spectrum when the correlated color temperature of the output light is 5000K. The spectrum of sunlight shown in Figure 11 is the spectrum of light from a standard light source with a correlated color temperature of 5000K in the D series defined by the Commission Internationale de l'Eclairage (CIE) (so-called CIE standard illuminant D50). In this specification, the spectrum of sunlight can be considered to be the spectrum of light from a standard light source with each correlated color temperature defined by the Commission Internationale de l'Eclairage. In other words, in this specification, sunlight can be considered to be light from a standard light source with each correlated color temperature defined by the Commission Internationale de l'Eclairage.

Furthermore, as shown in FIG. 11, the spectrum of the output light is a spectrum obtained by adding the spectrum of the first light shown in FIG. 5 and the spectrum of the second light shown in FIG. 6 at a predetermined ratio. The predetermined ratio is adjusted, for example, by the number of first light-emitting units 10 and second light-emitting units 20 included in the light source module 250, and the output power of each of the first light-emitting units 10 and second light-emitting units 20. The spectrum of the output light shown in FIG. 11 is, for example, the spectrum of the output light when the same current is passed through the first light-emitting units 10 and second light-emitting units 20 included in the light source module 250.

In the light source module 250, the ratio of the radiant flux in the wavelength range of 360 nm to 400 nm (the range enclosed by the dashed lines in Figure 11) to the total radiant flux in the visible light range of the output light is the same as the ratio of the radiant flux in the wavelength range of 360 nm to 400 nm to the total radiant flux in the visible light range of sunlight with the same correlated color temperature as the output light. Furthermore, in the light source module 250, the radiant flux in the wavelength range of 360 nm to 400 nm per unit total luminous flux in the visible light range of the output light (in other words, the ratio of the radiant flux to the total luminous flux) is the same as the radiant flux in the wavelength range of 360 nm to 400 nm per unit total luminous flux in the visible light range of sunlight with the same correlated color temperature as the output light. This allows the output light to contain the same proportion of violet light as sunlight, thereby reducing the burden on people even when using lighting that contains a violet component. Therefore, the light source module 250 can emit output light that contains a violet component and is suitable for use in lighting. Therefore, the light source module 250 can be used, for example, for lighting that has a myopia suppression effect. In addition, because it emits output light that includes a violet component that is missing from light sources used for general lighting, it enables lighting that is more desirable for people.

In this specification, the visible light region can be considered to be, for example, the wavelength range of 360 nm to 780 nm.

The radiant flux of the output light and sunlight corresponds to the area of the spectrum shown in Fig. 11. Therefore, when the wavelength is λ, the spectrum of the output light is P _L (λ), and the spectrum of sunlight is P _S (λ), the total radiant flux Φ _Lall in the visible light region of the output light and the radiant flux Φ _Lv in the wavelength range of 360 nm to 400 nm, as well as the total radiant flux Φ _Sall in the visible light region of sunlight and the radiant flux Φ _Sv in the wavelength range of 360 nm to 400 nm, are calculated by the following equations: _{P L} (λ) and P _S (λ) are functions of wavelength (unit: nm).

Furthermore, when the human luminous efficiency is K(λ), the total luminous flux Φ _VLall in the visible light region of the output light and the total luminous flux Φ _VSall in the visible light region of sunlight are calculated by the following formulas, where K(λ) is a function of wavelength (unit: nm).

Therefore, in the light source module 250, when the ratio of the radiant flux to the total radiant flux is calculated using the above formula with _PL (λ) and _PS (λ) having the same correlated color temperature as the output light, the radiant flux Φ _Lv /total radiant flux Φ _Lall is the same as the radiant flux Φ _Sv /total radiant flux Φ _Sall . Furthermore, in the light source module 250, when the radiant flux per unit total luminous flux is calculated using the above formula with _PL (λ) and _PS (λ) having the same correlated color temperature as the output light, the radiant flux Φ _Lv /total luminous flux Φ _VLall is the same as the radiant flux Φ _Sv /total luminous flux Φ _VSall . In this specification, "same" means "substantially the same." Here, "substantially the same" means, for example, that there is a difference of ±30% or less. Furthermore, "substantially the same" may mean that there is a difference of ±20% or less, or may mean that there is a difference of ±10% or less.

Furthermore, as shown in FIG. 11, the output light has the highest emission intensity, for example, at the wavelength of the emission peak of the second light-emitting element 21 (approximately 450 nm in this example). Furthermore, the number of peaks (maxima) in the spectrum of the output light is three in the example shown in FIG. 11. The number of peaks in the spectrum of the output light is not limited to three, and may be, for example, seven or less, or five or less. This allows the light source module 250 to be realized with a simple configuration. Furthermore, the number of peaks in the spectrum of the output light is, for example, three or more.

Note that the light source module 250 is configured so that the spectral characteristics of the output light and the spectral characteristics of sunlight satisfy the above relationship, and the multiple light-emitting units included in the light source module 250 are not limited to the above example. For example, instead of the second light-emitting unit 20, the light source module 250 may be configured to include multiple light-emitting units having multiple LED chips that emit light of different colors.

[Effects, etc.]
As described above, light source module 250 according to the present embodiment is a light source module 250 that emits output light and includes a plurality of light-emitting units. The plurality of light-emitting units include a plurality of light-emitting units that emit light of different light colors. The output light includes light emitted by each of the plurality of light-emitting units. In the output light of light source module 250, the ratio of radiant flux in the wavelength range of 360 nm to 400 nm to the total radiant flux in the visible light region is the same as that of sunlight having the same correlated color temperature as the output light of light source module 250.

As a result, the output light contains the same proportion of violet components as sunlight, reducing the burden on people even when using output light that contains violet components. Therefore, the light source module 250 can emit output light that contains violet components and is suitable for use in lighting. Furthermore, because the above proportion can be calculated using radiant flux, a numerical value directly related to the energy radiated to people can be used.

The light source module 250 according to this embodiment emits output light and includes multiple light-emitting units. The multiple light-emitting units include multiple light-emitting units that emit light of different light colors. The output light includes light emitted by each of the multiple light-emitting units. In the output light of the light source module 250, the radiant flux in the wavelength range of 360 nm to 400 nm per unit total luminous flux in the visible light region is the same as that of sunlight with the same correlated color temperature as the output light of the light source module 250.

As a result, the output light contains the same proportion of violet components as sunlight, reducing the burden on people even when using output light containing violet components. Therefore, the light source module 250 can emit output light that contains violet components and is suitable for use in lighting. Furthermore, because it uses radiant flux per unit total luminous flux, it is easy to apply to lighting design.

Also, for example, the multiple light-emitting units include a first light-emitting unit 10 that emits a first light and a second light-emitting unit 20 that emits a white second light. The first light-emitting unit 10 has a first light-emitting element 11. The second light-emitting unit 20 has a second light-emitting element 21 and a phosphor 22 that emits light when excited by light from the second light-emitting element 21. The output light includes the first light and the second light. The emission peak wavelength of the first light-emitting element 11 is shorter than the emission peak wavelength of the second light-emitting element 21 and is between 360 nm and 400 nm. The excitation spectrum of the phosphor 22 has a minimum value in the wavelength range between 360 nm and 400 nm, in which the first light-emitting element 11 has an emission intensity.

As a result, even if a portion of the first light containing a purple component emitted from the first light-emitting unit 10 enters the second light-emitting unit 20 due to diffusion or the like, the phosphor 22 is unlikely to be excited by the incident first light. This prevents the phosphor 22 from emitting light of an unintended wavelength due to the first light, and even when the light source module 250 includes the first light-emitting unit 10, changes in the color of the white second light emitted by the second light-emitting unit 20 are suppressed. Furthermore, because the first light is unlikely to be absorbed by the phosphor 22, a decrease in the amount of first light containing a purple component in the output light can be suppressed.

Furthermore, for example, the excitation spectrum of the phosphor 22 has a minimum value within the half-width range of the emission peak of the first light-emitting element 11.

This further suppresses excitation of the phosphor 22 by the first light in the second light-emitting section 20.

The lighting fixture 200 according to this embodiment also includes a light source module 250 and a lighting circuit 70 that supplies power to the light source module 250 to light the light source module 250.

This allows for the creation of a lighting fixture 200 that emits output light that contains a purple component and is suitable for use in lighting.

[Modification]
Next, a description will be given of a variation of embodiment 2. In the following description, differences from embodiment 1, the variation of embodiment 1, and embodiment 2 will be mainly described, and descriptions of commonalities will be omitted or simplified.

Figure 12 is a block diagram showing the configuration of lighting fixture 200a according to this modification. As shown in Figure 12, lighting fixture 200a differs from lighting fixture 200 according to embodiment 2 in that it includes light source module 250a instead of light source module 250, and in that it additionally includes control unit 90.

Light source module 250a includes a first light-emitting unit 10, a second light-emitting unit 20, and a third light-emitting unit 30. In other words, light source module 250a includes the third light-emitting unit 30 in addition to the configuration of light source module 250.

The third light-emitting unit 30 emits a white third light. The output light emitted by the light source module 250a includes the first light emitted by all of the first light-emitting units 10 included in the light source module 250a, the second light emitted by all of the second light-emitting units 20 included in the light source module 250a, and the third light emitted by all of the third light-emitting units 30 included in the light source module 250a. Note that, under control of the control unit 90, one of the second light-emitting units 20 and the third light-emitting unit 30 may not emit light, and the output light may not include one of the second light and the third light.

The third light-emitting unit 30 has the same configuration as the second light-emitting unit 20, except for the correlated color temperature of the light it emits. The third light-emitting unit 30 includes, for example, a light-emitting element, a phosphor, a sealing member, and a package, similar to the second light-emitting unit 20 shown in FIG. 4 . The light-emitting element, phosphor, sealing member, and package of the third light-emitting unit 30 may have the same configuration as the second light-emitting element 21, phosphor 22, sealing member 25, and package 27 of the second light-emitting unit 20. For example, the excitation spectrum of the phosphor of the third light-emitting unit 30 may have a minimum value in the wavelength range of 360 nm to 400 nm in which the first light-emitting element 11 has an emission intensity. The third light-emitting unit 30 differs from the second light-emitting unit 20 in the correlated color temperature of the light it emits because at least one of the output characteristics of the light-emitting element and the type and amount of the phosphor differs from the configuration of the corresponding second light-emitting element.

In the light source module 250a, the lighting of the first light-emitting unit 10, the second light-emitting unit 20, and the third light-emitting unit 30 is controlled independently. In the light source module 250a, for example, the first light-emitting unit 10, the second light-emitting unit 20, and the third light-emitting unit 30 are mounted on a circuit board so that power can be supplied independently.

The control unit 90 controls the light emission of the light source module 250a. The control unit 90, for example, adjusts the output of each of the first light-emitting unit 10, second light-emitting unit 20, and third light-emitting unit 30. The control unit 90, for example, uses the lighting circuit 70 to independently supply power to the first light-emitting unit 10, second light-emitting unit 20, and third light-emitting unit 30, and adjusts the light intensity of each of the first light, second light, and third light by individually changing the amount of current. In this way, the control unit 90 changes the correlated color temperature of the output light. Note that when the control unit 90 supplies power using the lighting circuit 70, some light-emitting units may not receive power depending on the correlated color temperature of the desired output light. Furthermore, the control unit 90 may control the output of the first light-emitting unit 10, second light-emitting unit 20, and third light-emitting unit 30 using PMW (Pulse Width Modulation) control.

The control unit 90 is realized, for example, by an LSI (Large Scale Integration), which is an integrated circuit (IC). The integrated circuit is not limited to an LSI and may be a dedicated circuit or a general-purpose processor. For example, the control unit 90 may be a microcontroller. The microcontroller includes, for example, a non-volatile memory that stores programs, a volatile memory that is a temporary storage area for executing programs, input/output ports, and a processor that executes the programs. The control unit 90 may also be a programmable FPGA (Field Programmable Gate Array) or a reconfigurable processor that allows the connections and settings of circuit cells within the LSI to be reconfigured. The functions performed by the control unit 90 may be realized by software or hardware.

Figure 13 is an xy chromaticity diagram in the CIE 1931 color space illustrating an example of changes in the correlated color temperature of the output light from the lighting device 200a according to this modified example. Figure 13 shows a case in which the second light-emitting unit 20 emits second light with chromaticity coordinate L2, and the third light-emitting unit 30 emits third light with chromaticity coordinate L3.

In the example shown in FIG. 13, the correlated color temperature of the second light is 6500 K, and the correlated color temperature of the third light is 3000 K. The correlated color temperatures of the second light and the third light are not particularly limited and are set according to the range in which the correlated color temperature of the output light is to be adjusted. In the example shown in FIG. 13, the chromaticity coordinate L2 of the second light and the chromaticity coordinate L3 of the third light are each chromaticity coordinates on the blackbody radiation locus, but they may be away from the blackbody radiation locus. In addition, at least one of the chromaticity coordinate L2 of the second light and the chromaticity coordinate L3 of the third light may be a chromaticity coordinate outside the specified range of correlated color temperatures.

The output light includes the first light in addition to the second and third lights, but the first light has little effect on the correlated color temperature of the output light. Therefore, the correlated color temperature of the output light is roughly determined by the ratio of the amount of second light to the amount of third light. For simplicity's sake, the following explanation will be given assuming that the correlated color temperature of the output light is determined by the ratio of the amount of second light to the amount of third light.

The control unit 90 controls the ratio between the output of the second light-emitting unit 20 and the output of the third light-emitting unit 30, thereby varying the chromaticity coordinates of the light resulting from the mixture of the second light and the third light between chromaticity coordinate L2 and chromaticity coordinate L3. This variation also causes the correlated color temperature of the output light to vary between the correlated color temperature of the second light and the correlated color temperature of the third light.

The control unit 90 also changes the correlated color temperature of the output light so that the ratio of the radiant flux in the wavelength range of 360 nm to 400 nm to the total radiant flux in the visible light range of the output light is the same as the ratio of the radiant flux in the wavelength range of 360 nm to 400 nm to the total radiant flux in the visible light range of sunlight with the same correlated color temperature as the output light. The control unit 90 also changes the correlated color temperature of the output light so that the radiant flux in the wavelength range of 360 nm to 400 nm per unit total luminous flux in the visible light range of the output light is the same as the radiant flux in the wavelength range of 360 nm to 400 nm per unit total luminous flux in the visible light range of sunlight with the same correlated color temperature as the output light. For example, the control unit 90 increases the output of the first light-emitting unit 10 when increasing the correlated color temperature of the output light, and decreases the output of the first light-emitting unit 10 when decreasing the correlated color temperature of the output light. The control unit 90 holds, for example, a data table that associates the correlated color temperature of the output light with the amount of power (current) supplied to each of the first light-emitting unit 10, second light-emitting unit 20, and third light-emitting unit 30, and controls the power supplied from the lighting circuit 70 to the light source module 250a based on the data table so that the desired correlated color temperature of the output light is achieved. The data table can be designed from the output characteristics of the first light-emitting unit 10, second light-emitting unit 20, and third light-emitting unit 30, and the spectra of the first light, second light, and third light.

As described above, the lighting fixture 200a according to this modification includes a control unit 90 that changes the correlated color temperature of the output light by adjusting the output of each of the multiple light-emitting elements of the light source module 250a. For example, the control unit 90 changes the correlated color temperature of the output light of the light source module 250a so that the ratio of the radiant flux in the wavelength range of 360 nm to 400 nm to the total radiant flux in the visible light range in the output light of the light source module 250a is the same as that of sunlight with the same correlated color temperature as the output light of the light source module 250a. Also, for example, the control unit 90 changes the correlated color temperature of the output light of the light source module 250a so that the radiant flux in the wavelength range of 360 nm to 400 nm per unit total luminous flux in the visible light range in the output light of the light source module 250a is the same as that of sunlight with the same correlated color temperature as the output light of the light source module 250a.

As a result, even when the correlated color temperature of the output light is changed, the proportion of the purple component in the output light is matched to sunlight at each correlated color temperature, thereby reducing the burden on people.

(others)
The light source module and lighting fixture according to the present invention have been described above based on the above-mentioned embodiment and modifications, but the present invention is not limited to the above-mentioned embodiment and modifications.

For example, at least one of the first light-emitting element 11 and the second light-emitting element 21 does not have to be an LED chip. For example, at least one of the first light-emitting element 11 and the second light-emitting element 21 may be an element other than an LED chip, such as a laser element or an organic EL (Electroluminescence) element.

Also, for example, the second light-emitting unit 20 may include a sintered body of phosphor 22 instead of the sealing member 25 in which phosphor 22 is dispersed. Also, the second light-emitting unit 20 may be a remote phosphor type light-emitting module.

In addition, the present invention also includes forms obtained by applying various modifications to each embodiment and each modification that would occur to a person skilled in the art, as well as forms realized by arbitrarily combining the components and functions of each embodiment and each modification within the scope of the spirit of the present invention.

Below are examples of the light source module and lighting fixture according to the present invention, as described based on the above-mentioned embodiment and modifications. The light source module and lighting fixture according to the present invention are not limited to the following examples.

A light source module according to a first aspect of the present invention is a light source module that emits output light, and includes a first light-emitting element, at least one purple light-emitting unit that emits first light, a second light-emitting element, and a phosphor that emits light when excited by light from the second light-emitting element, and at least one white light-emitting unit that emits white second light. The output light includes the first light and the second light, the emission peak wavelength of the first light-emitting element is shorter than the emission peak wavelength of the second light-emitting element and is between 350 nm and 410 nm, and the excitation spectrum of the phosphor has a minimum value in the wavelength range of 350 nm and 410 nm in which the first light-emitting element has an emission intensity.

The light source module according to the second aspect of the present invention is the light source module according to the first aspect, wherein the excitation spectrum has a minimum value within the half-width range of the emission peak of the first light-emitting element.

A light source module according to a third aspect of the present invention is a light source module according to the first or second aspect, wherein, in the excitation spectrum, the intensity at the emission peak wavelength of the first light-emitting element is less than half the intensity at the emission peak wavelength of the second light-emitting element.

A light source module according to a fourth aspect of the present invention is a light source module according to any one of the first to third aspects, wherein the at least one purple light-emitting unit includes a first purple light-emitting unit, and the at least one white light-emitting unit includes, of the at least one white light-emitting unit, a first white light-emitting unit closest to the first purple light-emitting unit and a second white light-emitting unit closest to the first white light-emitting unit, and the distance between the first purple light-emitting unit and the first white light-emitting unit is longer than the distance between the first white light-emitting unit and the second white light-emitting unit.

A light source module according to a fifth aspect of the present invention is a light source module according to any one of the first to fourth aspects, wherein the output light has the highest emission intensity at the emission peak wavelength of the first light-emitting element.

A lighting fixture according to a sixth aspect of the present invention comprises a light source module according to any one of the first to fifth aspects, and a lighting circuit that supplies power to the light source module for lighting the light source module.

10, 10a First light-emitting unit (purple light-emitting unit)
11 First light emitting element 20, 20a, 20b Second light emitting section (white light emitting section)
21 Second light-emitting element 22 Phosphor 50, 50a, 250, 250a Light source module 70 Lighting circuit 100, 200, 200a Lighting fixture

Claims (6)

A light source module that emits output light,
at least one purple light-emitting unit having a first light-emitting element and emitting a first light;
at least one white light emitting unit that has a second light emitting element and a phosphor that is excited by light from the second light emitting element and emits light, and that emits white second light;
the output light includes the first light and the second light,
an emission peak wavelength of the first light-emitting element is shorter than an emission peak wavelength of the second light-emitting element and is 350 nm or more and 410 nm or less;
the excitation spectrum of the phosphor has a minimum value in a wavelength range of 350 nm or more and 410 nm or less in which the first light-emitting element has an emission intensity;
Light source module. the excitation spectrum has a minimum value within a half width range of an emission peak of the first light-emitting element;
The light source module according to claim 1 . In the excitation spectrum, the intensity at the wavelength of the emission peak of the first light-emitting element is half or less of the intensity at the wavelength of the emission peak of the second light-emitting element.
The light source module according to claim 1 . the at least one purple light-emitting unit includes a first purple light-emitting unit;
the at least one white light emitting unit includes a first white light emitting unit that is closest to the first purple light emitting unit and a second white light emitting unit that is closest to the first white light emitting unit,
a distance between the first purple light-emitting unit and the first white light-emitting unit is longer than a distance between the first white light-emitting unit and the second white light-emitting unit;
The light source module according to claim 1 . the output light has the highest emission intensity at the wavelength of the emission peak of the first light-emitting element;
The light source module according to claim 1 . The light source module according to any one of claims 1 to 5;
a lighting circuit that supplies power to the light source module for lighting the light source module,
Lighting fixtures.