Luminaire

Abstract

To provide a luminaire capable of changing the color of illumination light while using a plurality of light emitting elements for emitting light of the same color gamut.SOLUTION: A luminaire 1 emits illumination light Lw, and includes a light source unit 10 for emitting source light Lb, and a phosphor 21 that is excited by the source light Lb to emit fluorescence Ly. The light source unit 10 has a first light-emitting element 11 for emitting first light Lb1, and a second light-emitting element 12 for emitting second light Lb2 that has the same color gamut as the first light Lb1 and a different dominant wavelength from the first light Lb1. The source light Lb includes the first light Lb1 and the second light Lb2, the illumination light Lw is composite light of the source light 20 and the fluorescence Ly, and the chromaticity of the illumination light Lw is changed by changing the dominant wavelength of the source light Lb to change the light intensity ratio between the source light Lb and the fluorescence Ly.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a lighting device. [Background technology]

[0002] Conventionally, lighting devices using light-emitting elements such as LEDs or semiconductor lasers as light sources are known. For example, a lighting device using a semiconductor laser as a light source includes a semiconductor laser that emits laser light and a phosphor that is excited by the light emitted from the semiconductor laser and emits fluorescence (Patent Document 1). In such lighting devices, the fluorescence generated by absorbing a part of the laser light in the phosphor is mixed with the laser light that is not absorbed by the phosphor to obtain illumination light of a desired color. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-64597 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is desirable for a lighting device to be able to change not only the brightness of the illumination light but also the chromaticity of the illumination light, i.e., a lighting device capable of dimming control and color adjustment control is desirable.

[0005] However, in a lighting device equipped with light-emitting elements, in order to change the chromaticity of the illumination light, multiple types of light-emitting elements with different emission colors are required. In particular, in order to perform color adjustment control in a lighting device using semiconductor lasers as light-emitting elements, it is necessary to use three types of semiconductor lasers: a red semiconductor laser that emits red (R) laser light, a green semiconductor laser that emits green (G) laser light, and a blue semiconductor laser that emits blue (B) laser light.

[0006] The present invention has been made in consideration of such problems, and aims to provide a lighting device that can change the chromaticity of illumination light while using multiple light-emitting elements that emit light in the same color gamut. [Means for solving the problem]

[0007] In order to achieve the above object, one aspect of the illumination device according to the present invention is an illumination device that irradiates illumination light, comprising: a light source unit that emits source light; and a first phosphor that is excited by the source light to emit a first fluorescence, wherein the light source unit has a first light-emitting element that emits the first light, and a second light-emitting element that emits a second light having the same color gamut as the first light and a dominant wavelength different from that of the first light, the source light includes at least one of the first light and the second light, the illumination light is a composite light of the source light and the first fluorescence, and the chromaticity of the illumination light is changed by changing the dominant wavelength of the source light to change the light intensity ratio between the source light and the first fluorescence. Effect of the Invention

[0008] According to the present invention, it is possible to realize an illumination device that is capable of changing the chromaticity of illumination light while using a plurality of light-emitting elements that emit light in the same color gamut. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a configuration of a lighting device according to an embodiment. [Diagram 2] FIG. 2 is a diagram for explaining a color adjustment control method using the lighting device according to the embodiment. [Diagram 3] FIG. 3 is a diagram for explaining another color adjustment control method using the lighting device according to the embodiment. [Figure 4] FIG. 4 is a diagram for explaining still another color adjustment control method using the lighting device according to the embodiment. [Diagram 5] FIG. 5 is a diagram showing the emission spectra of the first light-emitting element and the second light-emitting element when Tc=20° C., 40° C., and 60° C. [Figure 6] FIG. 6 is a diagram showing a configuration of an illumination device according to the first modification. [Figure 7] FIG. 7 is a diagram showing the excitation spectra (absorption characteristics) and emission spectra of two types of phosphors used in the lighting device according to the first modification. [Figure 8] FIG. 8 is an xy chromaticity diagram showing changes in chromaticity of illumination light when color adjustment control is performed using a lighting device according to the embodiment and changes in chromaticity of illumination light when color adjustment control is performed using a lighting device according to modification 1. [Figure 9] FIG. 9 is a diagram showing conditions when the color adjustment control of FIG. 8 is performed. [Figure 10] FIG. 10 is a diagram showing an emission spectrum of a phosphor section at Tc=20° C. in a lighting device including a phosphor section having a phosphor composed of a YAG phosphor and a phosphor composed of a SCASN phosphor. [Figure 11] FIG. 11 is a diagram showing a configuration of an illumination device according to the second modification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that each of the embodiments described below shows a specific example of the present invention. Therefore, the numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present invention. Therefore, among the components in the following embodiments, components that are not described in the independent claims showing the highest concept of the present invention will be described as optional components.

[0011] Note that each figure is a schematic diagram and is not necessarily a precise illustration. In addition, in each figure, substantially the same configuration is given the same reference numeral, and duplicated explanations are omitted or simplified. In addition, in this specification, the terms "upper" and "lower" do not necessarily refer to the upper direction (vertically upward) and the lower direction (vertically downward) in absolute spatial recognition.

[0012] (Embodiment) First, the overall configuration of a lighting device 1 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing the configuration of a lighting device 1 according to an embodiment.

[0013] As shown in Fig. 1, the illumination device 1 includes a light source unit 10 that emits source light Lb, and a phosphor unit 20 into which the source light Lb emitted by the light source unit 10 is incident. The illumination device 1 emits illumination light Lw of a predetermined color. In this embodiment, the illumination device 1 emits white light as the illumination light Lw. The illumination light Lw is a composite light of the source light Lb emitted from the light source unit 10 and the fluorescence Ly generated by the phosphor unit 20.

[0014] The light source unit 10 has a first light emitting element 11 that emits a first light Lb1 and a second light emitting element 12 that emits a second light Lb2. The light source light Lb emitted by the light source unit 10 includes at least one of the first light Lb1 and the second light Lb2.

[0015] The first light emitting element 11 and the second light emitting element 12 are semiconductor light emitting elements such as a semiconductor laser or an LED. In this embodiment, the first light emitting element 11 and the second light emitting element 12 are configured by a semiconductor laser that emits laser light. In other words, the first light Lb1 and the second light Lb2 are laser light having a monochromatic optical spectrum.

[0016] As an example, each of the first light-emitting element 11 and the second light-emitting element 12 is a TO-CAN package semiconductor laser, and includes a semiconductor laser chip that emits laser light, a post on which the semiconductor laser chip is mounted, a stem having a disk-shaped base that supports the post, a pair of lead pins that penetrate the base, and a metal cap that is placed on the base so as to cover the post on which the semiconductor laser chip is mounted. The laser light emitted from the semiconductor laser chip is emitted to the outside through an opening of the cap. The semiconductor laser chip is made of, for example, a nitride-based semiconductor material. The semiconductor laser chip in the first light-emitting element 11 emits laser light as the first light Lb1. The semiconductor laser chip in the second light-emitting element 12 emits laser light as the second light Lb2.

[0017] The first light Lb1 emitted by the first light emitting element 11 and the second light Lb2 emitted by the second light emitting element 12 have the same color gamut but different dominant wavelengths. That is, the color of the first light Lb1 and the color of the second light Lb2 are the same, but the dominant wavelength of the first light Lb1 and the dominant wavelength of the second light Lb2 are different. In this way, the light source unit 10 has the first light emitting element 11 and the second light emitting element 12 as a plurality of light emitting elements that emit light of the same color gamut but with different dominant wavelengths.

[0018] In the present embodiment, the first light Lb1 and the second light Lb2 are blue in color. For example, the first light Lb1 and the second light Lb2 are blue laser lights in the blue band having a peak wavelength in the range of 430 nm to 480 nm.

[0019] Moreover, the dominant wavelength of the first light Lb1 is shorter than the dominant wavelength of the second light Lb2. That is, the first light emitting element 11 is a blue semiconductor laser that emits the first blue light Lb1 with a short wavelength, and the second light emitting element 12 is a blue semiconductor laser that emits the second blue light Lb2 with a long wavelength. As an example, the dominant wavelength of the first light Lb1 is about 440 nm, and the dominant wavelength of the second light Lb2 is about 455 nm. If the difference between the dominant wavelength of the first light Lb1 and the dominant wavelength of the second light Lb2 is Δλ [nm], it is preferable that 0<Δλ≦40.

[0020] Note that the "dominant wavelength" is a different concept from the "peak wavelength". Therefore, the value of the "dominant wavelength" is different from the value of the "peak wavelength", but in cases where the optical spectrum (spectral distribution) of the laser light has a Gaussian distribution, the value of the "dominant wavelength" and the value of the "peak wavelength" may be the same.

[0021] The phosphor section 20 is a phosphor device that emits fluorescence Ly using light incident on the phosphor section 20 as excitation light. Specifically, the phosphor section 20 emits fluorescence Ly using source light Lb emitted from the light source section 10 as excitation light.

[0022] The phosphor section 20 includes a phosphor 21 and a substrate 22 that supports the phosphor 21. In this embodiment, the phosphor section 20 is a transmissive phosphor device that transmits the excitation light incident on the phosphor section 20. The substrate 22 may reflect the fluorescence Ly generated in the phosphor section 20. Therefore, the substrate 22 may be transmissive to the light source light Lb and reflective to the fluorescence Ly. For example, the substrate 22 includes a translucent substrate and a dichroic film formed on the translucent substrate. In this case, the dichroic film may have a spectral characteristic that has high transmissivity to the light source light Lb and high reflectivity to the fluorescence Ly. The light source light Lb emitted from the light source section 10 enters the phosphor section 20 from the rear surface (the surface on the light source section 10 side) of the substrate 22, and enters the phosphor 21 through the substrate 22.

[0023] The phosphor 21 is a phosphor optical element that emits fluorescence using light incident on the phosphor 21 as excitation light. Specifically, the phosphor 21 is excited by source light Lb (excitation light) from the light source unit 10 to emit fluorescence Ly. When the source light Lb from the light source unit 10 is incident on the phosphor 21, the phosphor 21 emits fluorescence Ly of a predetermined color in the visible range. The phosphor 21 emits fluorescence Ly using light with a shorter wavelength than the fluorescence Ly as excitation light. In this embodiment, the phosphor 21 is a yellow phosphor layer made of a yellow phosphor, and emits yellow light as the fluorescence Ly.

[0024] The phosphor 21 may be a phosphor ceramic layer made of ceramics, or a phosphor sealing resin layer in which phosphor particles are sealed with a binder (binding agent). However, when the first light-emitting element 11 and the second light-emitting element 12 are made of semiconductor lasers as in this embodiment, the phosphor 21 is preferably made of a phosphor ceramic layer having excellent heat resistance and heat dissipation properties.

[0025] The phosphor 21 in the yellow phosphor layer is, for example, YAlO 12 A YAG phosphor layer composed of YAG (yttrium aluminum garnet) represented by Ce, or Lu3Al5O 12 A LuAG phosphor layer made of LuAG (lutetium aluminum garnet) represented by the formula: Ce can be used. In this embodiment, the phosphor 21 is a phosphor ceramic layer made of only a sintered YAG phosphor of a single crystal phase.

[0026] The light-transmitting substrate constituting the substrate 22 is preferably a substrate having a high light transmittance. Specifically, the light-transmitting substrate constituting the substrate 22 is preferably a transparent substrate having a high light transmittance so that the other side can be seen through. As an example, the light transmittance of the light-transmitting substrate is 90% or more, and more preferably 95% or more. In addition, the light-transmitting substrate is preferably a substrate having not only a high light transmittance but also high heat resistance. As such a light-transmitting substrate, an alumina substrate made of Al2O3, an aluminum nitride substrate made of AlN, a gallium nitride substrate made of GaN, a sapphire substrate, a glass substrate, or the like can be used. An anti-reflection film may be formed on the back surface (light incident side) of the substrate 22.

[0027] As shown in FIG. 1, the lighting device 1 in this embodiment further includes a heat sink 30, a condenser lens 40, an optical fiber 50, a mirror pipe 60, and a projection lens .

[0028] The light source section 10, the heat sink 30, and the condensing lens 40 constitute a light source unit. The phosphor section 20, the mirror pipe 60, and the projection lens 70 constitute a lamp. The light source section 10, the heat sink 30, and the condensing lens 40 may be housed in a housing 81. The phosphor section 20, the mirror pipe 60, and the projection lens 70 may be housed in a housing 82. In this case, the housing 81 has an opening for emitting light to the outside. The housing 82 has an opening for letting light in and an opening for emitting light to the outside. The housings 81 and 82 are made of metal or resin.

[0029] The heat sink 30 is a metal member such as aluminum or copper. The heat sink 30 also functions as a support member for supporting the first light emitting element 11 and the second light emitting element 12. The first light emitting element 11 and the second light emitting element 12 are fixed to the heat sink 30. The heat sink 30 may have a plurality of heat dissipation fins.

[0030] The condenser lens 40 is disposed on the emission side of the light source light of the light source unit 10, and condenses the light source light Lb emitted from the light source unit 10. The light source light Lb emitted from the light source unit 10 is condensed by the condenser lens 40 and enters the optical fiber 50. Specifically, the condenser lens 40 condenses each of the first light Lb1 emitted by the first light emitting element 11 and the second light Lb2 emitted by the second light emitting element 12. That is, the first light Lb1 emitted by the first light emitting element 11 and the second light Lb2 emitted by the second light emitting element 12 are condensed by the condenser lens 40 and enter the optical fiber 50.

[0031] The optical fiber 50 is an example of a light-guiding member that guides light. The optical fiber 50 is a transmission body having a double structure in which a core having a high refractive index is wrapped with a cladding layer having a lower refractive index than the core, and is made of a material such as quartz glass or resin. The optical fiber 50 transmits the light source light Lb, which is a laser light emitted from the light source unit 10 and focused by the focusing lens 40, to the mirror pipe 60. The light source light Lb focused by the focusing lens 40 may be directly coupled to the mirror pipe 60 without using the optical fiber 50. In this case, a lighting device in which a light source unit and a lamp are integrated is formed.

[0032] The mirror pipe 60 is a cylindrical body with a rectangular cross section. The inner surface of the mirror pipe 60 is a mirror surface (reflective surface). The mirror pipe 60 uniformizes the light intensity of the light source light Lb that enters the mirror pipe 60 and outputs it. Specifically, the mirror pipe 60 reduces the peak of the light intensity of the light source light Lb, which is a laser light, and outputs it.

[0033] The projection lens 70 collects and projects onto a desired area the illumination light Lw (white light) which is a composite light of the fluorescence Ly generated by the phosphor section 20 and the light source light Lb of the light source section 10 transmitted through the phosphor section 20. The projection lens 70 may be made of, for example, a resin material such as acrylic or polycarbonate, or may be made of a glass material.

[0034] Although not shown, the lighting device 1 may have a power supply device (power supply circuit) for supplying power to the light source unit 10. Specifically, the power supply device supplies power to each of the first light-emitting element 11 and the second light-emitting element 12 individually. This allows the first light-emitting element 11 and the second light-emitting element 12 to emit light individually. The power supply device does not have to be included in the lighting device 1. In other words, the power supply device may be an external power source that is provided separately from the lighting device 1.

[0035] In the lighting device 1 configured in this manner, the source light Lb emitted from the light source section 10 is incident on the phosphor section 20, whereby illumination light Lw of a predetermined color is emitted.

[0036] Specifically, when power is supplied to the light source unit 10 by the power supply device, the light source light Lb is emitted from the light source unit 10. The light source light Lb emitted from the light source unit 10 is collected by the collecting lens 40 and enters the optical fiber 50. More specifically, when power is supplied to the first light-emitting element 11 and the second light-emitting element 12 by the power supply device, the first light Lb1 is emitted from the first light-emitting element 11 and the second light Lb2 is emitted from the second light-emitting element 12. Then, the first light Lb1 emitted from the first light-emitting element 11 and the second light Lb2 emitted from the second light-emitting element 12 are collected by the collecting lens 40 as the light source light Lb and enter the optical fiber 50.

[0037] The light source light Lb of the light source unit 10 that enters the optical fiber 50 is transmitted through the optical fiber 50 and enters the mirror pipe 60. The light intensity of the light source light Lb of the light source unit 10 that enters the mirror pipe 60 is equalized by the mirror pipe 60 and the light enters the phosphor unit 20. Specifically, the light source light Lb of the light source unit 10 enters the substrate 22 of the phosphor unit 20.

[0038] The light source light Lb (Lb1, Lb2) of the light source unit 10 incident on the phosphor unit 20 passes through the substrate 22 and reaches the phosphor 21. As a result, the phosphor 21 is excited by the light source light Lb of the light source unit 10 and emits fluorescence Ly. In this embodiment, the light source light Lb of the light source unit 10 is blue, and the phosphor 21 is a yellow phosphor layer. In this case, the blue light source light Lb is incident on the phosphor 21. As a result, the phosphor 21 absorbs a part of the light source light Lb and is excited to emit yellow light as fluorescence Ly. Then, in the phosphor 21, this yellow light is mixed with another part (blue light) of the light source light Lb that was not absorbed by the phosphor 21 (yellow phosphor layer) to generate white light as a composite light, and the white light is emitted from the phosphor unit 20 as the illumination light Lw. The illumination light Lw emitted from the phosphor 20 is collected by the projection lens 70 and projected onto a desired area.

[0039] Next, a color adjustment control method using the lighting device 1 according to the embodiment will be described with reference to Fig. 2. Fig. 2 is a diagram for explaining the color adjustment control method using the lighting device 1 according to the embodiment.

[0040] In the lighting device 1 of the present embodiment, the color adjustment control of the lighting device 1 is performed by utilizing the fact that the luminous efficiency (conversion efficiency) of the phosphor changes depending on the wavelength of the excitation light. In other words, the chromaticity of the illumination light Lw emitted from the lighting device 1 is controlled. A specific description will be given below.

[0041] When the wavelength of the excitation light incident on the phosphor 21 is short, the luminous efficiency of the phosphor 21 is relatively low, and when the wavelength of the excitation light incident on the phosphor 21 is long, the luminous efficiency of the phosphor 21 is relatively high.

[0042] For this reason, as shown in FIG. 2, in the case where the light source unit 10 has a first light emitting element 11 that emits a first light Lb1 of blue laser light having a main wavelength of a short wavelength λ1 and a second light emitting element 12 that emits a second light Lb2 of blue laser light having a main wavelength of a long wavelength λ2 (λ2>λ1), and the phosphor 21 is a yellow phosphor layer that emits yellow fluorescence Ly, as shown in FIG. 2(a), when the second light emitting element 12 is not emitted and only the first light emitting element 11 is emitted so that the light source light Lb of the light source unit 10 contains only the first light Lb1 of the short wavelength (Lb=Lb1), the main wavelength of the light source light Lb becomes shorter. In this case, the wavelength of the excitation light incident on the phosphor 21 becomes shorter, so that the luminous efficiency of the phosphor 21 becomes lower, and the light intensity of the yellow fluorescence Ly generated by the phosphor 21 becomes smaller. As a result, the proportion of the first light Lb1, which is blue laser light, that is transmitted through the phosphor 21 without being absorbed by the phosphor 21 becomes larger. This increases the color temperature of the white illumination light Lw, which is a composite light of the first light Lb1, which is a blue laser light, and the yellow fluorescence Ly. Thus, the lighting state of the illumination device 1 in the case of FIG. 2(a) is a high color temperature state (first lighting state) in which the illumination light Lw with a high color temperature is emitted.

[0043] On the other hand, as shown in FIG. 2(b), when the first light emitting element 11 is not emitted and only the second light emitting element 12 is emitted and the light source light Lb of the light source unit 10 includes only the second light Lb2 having a long wavelength (Lb=Lb2), the main wavelength of the light source light Lb becomes longer. In this case, the wavelength of the excitation light incident on the phosphor 21 becomes longer, so that the luminous efficiency of the phosphor 21 becomes higher and the light intensity of the yellow fluorescence Ly generated by the phosphor 21 becomes higher. As a result, the ratio of the second light Lb2, which is a blue laser light that is not absorbed by the phosphor 21 and passes through the phosphor 21 becomes smaller. This lowers the color temperature of the white illumination light Lw, which is a composite light of the second light Lb2, which is a blue laser light, and the yellow fluorescence Ly. In this way, the lighting state of the illumination device 1 in the case of FIG. 2(b) is a low color temperature state (second illumination state) in which the illumination light Lw with a low color temperature is irradiated.

[0044] Also, as shown in FIG. 2(c), when both the first light emitting element 11 and the second light emitting element 12 are emitted and the light source light Lb of the light source unit 10 includes the first light Lb1 with a short wavelength and the second light Lb2 with a long wavelength (Lb=Lb1+Lb2), the dominant wavelength of the light source light Lb becomes intermediate between the cases of FIG. 2(a) and FIG. 2(b). In this case, the luminous efficiency of the phosphor 21 also becomes intermediate, and the light intensity of the yellow fluorescence Ly generated by the phosphor 21 also becomes intermediate. As a result, the ratio of the first light Lb1 and the second light Lb2, which are blue laser light and are transmitted through the phosphor 21 without being absorbed by the phosphor 21, also becomes intermediate. As a result, the color temperature of the white illumination light Lw, which is the composite light of the first light Lb1 and the second light Lb2, which are blue laser light, and the yellow fluorescence Ly, becomes intermediate. In this way, the lighting state of the lighting device 1 in the case of FIG. 2(c) is a medium color temperature state (third lighting state) in which illumination light Lw with a medium color temperature is emitted.

[0045] The light intensity (light output) of the first light Lb1 emitted by the first light-emitting element 11 is smaller in the case of FIG. 2(c) than in the case of FIG. 2(a). For example, the light intensity of the first light Lb1 of the first light-emitting element 11 in the case of FIG. 2(c) is half of the light intensity of the first light Lb1 of the first light-emitting element 11 in the case of FIG. 2(a). Also, the light intensity (light output) of the second light Lb2 emitted by the second light-emitting element 12 is smaller in the case of FIG. 2(c) than in the case of FIG. 2(b). For example, the light intensity of the second light Lb2 of the second light-emitting element 12 in the case of FIG. 2(c) is half of the light intensity of the second light Lb2 of the second light-emitting element 12 in the case of FIG. 2(b). In the present embodiment, the intensity ratios of the first light Lb1 and the second light Lb2 are 1:0, 0:1, and 0.5:0.5 in each of (a), (b), and (c) of FIG. 2, but are not limited to this.

[0046] 2(a), (b) and (c), the light intensity (light output) of the first light Lb1 emitted by the first light emitting element 11 is changed, and the light intensity (light output) of the second light Lb2 emitted by the second light emitting element 12 is changed. That is, the light intensity ratio between the first light Lb1 emitted by the first light emitting element 11 and the second light Lb2 emitted by the second light emitting element 12 is changed. This changes the dominant wavelength of the light source light Lb, which is the composite light of the first light Lb1 and the second light Lb2, and changes the light intensity ratio between the light source light Lb and the fluorescence Ly generated by the phosphor 21, and changes the color temperature of the illumination light Lw. That is, the chromaticity of the illumination light Lw irradiated from the illumination device 1 can be changed.

[0047] The light intensity (light output) of the first light Lb1 of the first light-emitting element 11 and the light intensity (light output) of the second light Lb2 of the second light-emitting element 12 can be controlled by a control unit (not shown). The control unit can be configured by, for example, a control circuit. This control unit may also be a part of a power supply device.

[0048] In addition, in the present embodiment, only the three lighting states of (a), (b), and (c) in Fig. 2 are illustrated, but the present invention is not limited thereto. For example, the lighting state of the lighting device 1 can be changed countlessly by changing the intensity ratio of the first light Lb1 and the second light Lb2 between 1:0 and 0:1 in an analog or stepwise manner. That is, the color temperature of the illumination light Lw of the lighting device 1 can be changed analog or stepwise to a color temperature between the case of (a) in Fig. 2 and the case of (c) in Fig. 2, or the color temperature can be changed analog or stepwise to a color temperature between the case of (b) in Fig. 2 and the case of (c) in Fig. 2.

[0049] Next, another color adjustment control method using the lighting device 1 according to the embodiment will be described with reference to Fig. 3. Fig. 3 is a diagram for explaining another color adjustment control method using the lighting device 1 according to the embodiment.

[0050] In the color adjustment control method shown in Figure 2 above, the main wavelength of the light source light Lb of the light source unit 10 is changed by changing the light intensity ratio between the first light Lb1 emitted by the first light-emitting element 11 and the second light-emitting element 12.However, in the color adjustment control method shown in Figure 3, the second light-emitting element 12 of the first light-emitting element 11 and the second light-emitting element 12 is not made to emit light and the light output of the second light-emitting element 12 is stopped while only the first light-emitting element 11 is made to emit light, and the main wavelength of the light source light Lb is changed by changing only the main wavelength of the first light Lb1 emitted by the first light-emitting element 11.

[0051] In the color adjustment control method shown in Fig. 3, the dominant wavelength of the light source light Lb is changed by utilizing the fact that the dominant wavelength of the semiconductor laser changes depending on the temperature. Specifically, the semiconductor laser has a characteristic that the dominant wavelength shifts to the longer wavelength side as the temperature increases, and the dominant wavelength shifts to the shorter wavelength side as the temperature decreases. Therefore, in the lighting device 1 of this embodiment, the temperature of the first light emitting element 11 is changed by the temperature control element 90 to change the dominant wavelength of the first light Lb1 emitted from the first light emitting element 11, thereby changing the dominant wavelength of the light source light Lb.

[0052] The temperature of the first light-emitting element 11 can be controlled, for example, as the temperature (Tc) of a heat sink 30 (see FIG. 1) to which the first light-emitting element 11 is attached. Specifically, the temperature (Tc) of the first light-emitting element 11 can be changed by a temperature control element 90 connected to the heat sink 30. The temperature control element 90 is, for example, a Peltier element, and can be controlled, for example, by a control unit (not shown). By using a Peltier element as the temperature control element 90, the first light-emitting element 11 can be cooled by the temperature control element 90 via the heat sink 30.

[0053] For example, as shown in (a) of FIG. 3, when the temperature of the first light-emitting element 11 is set to a low temperature (Tc=20° C.), the lower the temperature of the first light-emitting element 11, which is a semiconductor laser, the shorter the emission wavelength becomes, so that the dominant wavelength of the first light Lb1, which is a blue laser light emitted by the first light-emitting element 11, is the wavelength λ1 and becomes shorter. In (a) of FIG. 3, since the first light Lb1 and the light source light Lb are the same, the dominant wavelength of the light source light Lb also becomes shorter. In this case, the wavelength of the excitation light incident on the phosphor 21 becomes shorter, so that the luminous efficiency of the phosphor 21 becomes lower, and the light intensity of the yellow fluorescence Ly generated by the phosphor 21 becomes smaller. As a result, the color temperature of the white illumination light Lw, which is a composite light of the first light Lb1, which is a blue laser light, and the yellow fluorescence Ly, becomes higher.

[0054] On the other hand, as shown in FIG. 3B, when the temperature of the first light emitting element 11 is set to a medium temperature (Tc=40° C.), the emission wavelength of the first light emitting element 11, which is a semiconductor laser, shifts to the long wavelength side as the temperature increases, so that the dominant wavelength of the first light Lb1, which is a blue laser light emitted by the first light emitting element 11, becomes longer, being wavelength λ1+α. In FIG. 3B, the first light Lb1 and the light source light Lb are the same, so the dominant wavelength of the light source light Lb also becomes longer. In this case, the wavelength of the excitation light incident on the phosphor 21 becomes longer, so that the luminous efficiency of the phosphor 21 increases, and the light intensity of the yellow fluorescence Ly generated by the phosphor 21 increases. As a result, the color temperature of the white illumination light Lw, which is a composite light of the first light Lb1, which is a blue laser light, and the yellow fluorescence Ly, becomes lower.

[0055] Also, as shown in FIG. 3(c), when the temperature of the first light emitting element 11 is set to a high temperature (Tc=60° C.), the emission wavelength of the first light emitting element 11 shifts to the longer wavelength side than in FIG. 3(b), so that the dominant wavelength of the first light Lb1, which is a blue laser light emitted by the first light emitting element 11, becomes wavelength λ1+β, which is longer than wavelength λ1+α. In FIG. 3(c), the first light Lb1 and the light source light Lb are the same, so the dominant wavelength of the light source light Lb also becomes longer. In this case, the wavelength of the excitation light incident on the phosphor 21 becomes longer, the luminous efficiency of the phosphor 21 becomes higher, and the light intensity of the yellow fluorescence Ly generated by the phosphor 21 becomes higher. As a result, the color temperature of the white illumination light Lw, which is a composite light of the first light Lb1, which is a blue laser light, and the yellow fluorescence Ly, becomes lower.

[0056] In Fig. 3, the temperature of the first light-emitting element 11 is controlled to change the main wavelength of the light source light Lb while the optical output of the second light-emitting element 12 is stopped, but this is not limiting. Specifically, as shown in Fig. 4, the temperature of the second light-emitting element 12 may be controlled to change the main wavelength of the light source light Lb while the optical output of the first light-emitting element 11 is stopped. In other words, the temperature of one of the first light-emitting element 11 and the second light-emitting element 12 may be changed by the temperature control element 90 while the optical output of the other of the first light-emitting element 11 and the second light-emitting element 12 is stopped, thereby changing the main wavelength of the light source light Lb.

[0057] Fig. 4 is a diagram for explaining yet another color adjustment control method using the lighting device 1 according to the embodiment. In Fig. 4, the temperature control element 90 controls the temperature of the second light-emitting element 12. The color adjustment control method shown in Fig. 4 will be explained below.

[0058] First, as shown in FIG. 4(a), when the temperature of the second light-emitting element 12 is set to a low temperature (Tc=20° C.), the lower the temperature of the second light-emitting element 12, which is a semiconductor laser, the shorter the emission wavelength becomes, so that the dominant wavelength of the second light Lb2, which is a blue laser light emitted by the second light-emitting element 12, is the wavelength λ2 and becomes shorter. In FIG. 4(a), the second light Lb2 and the light source light Lb are the same, so the dominant wavelength of the light source light Lb also becomes shorter. In this case, the wavelength of the excitation light incident on the phosphor 21 becomes shorter, so the luminous efficiency of the phosphor 21 becomes lower, and the light intensity of the yellow fluorescence Ly generated by the phosphor 21 becomes smaller. As a result, the color temperature of the white illumination light Lw, which is a composite light of the second light Lb2, which is a blue laser light, and the yellow fluorescence Ly, becomes higher.

[0059] On the other hand, as shown in FIG. 4B, when the temperature of the second light-emitting element 12 is set to a medium temperature (Tc=40° C.), the emission wavelength of the second light-emitting element 12, which is a semiconductor laser, shifts to the long wavelength side as the temperature increases, so that the dominant wavelength of the second light Lb2, which is a blue laser light emitted by the second light-emitting element 12, becomes longer, being wavelength λ2+α. In FIG. 4B, the second light Lb2 and the light source light Lb are the same, so the dominant wavelength of the light source light Lb also becomes longer. In this case, the wavelength of the excitation light incident on the phosphor 21 becomes longer, so that the luminous efficiency of the phosphor 21 increases, and the light intensity of the yellow fluorescence Ly generated by the phosphor 21 increases. As a result, the color temperature of the white illumination light Lw, which is a composite light of the second light Lb2, which is a blue laser light, and the yellow fluorescence Ly, becomes lower.

[0060] Also, as shown in FIG. 4(c), when the temperature of the second light emitting element 12 is set to a high temperature (Tc=60° C.), the emission wavelength of the second light emitting element 12 shifts to the longer wavelength side than in FIG. 4(b), so that the dominant wavelength of the second light Lb2, which is a blue laser light emitted by the second light emitting element 12, becomes the wavelength λ2+β, which is longer than the wavelength λ2+α. In FIG. 4(c), the second light Lb2 and the light source light Lb are the same, so the dominant wavelength of the light source light Lb also becomes longer. In this case, the wavelength of the excitation light incident on the phosphor 21 becomes longer, the luminous efficiency of the phosphor 21 becomes higher, and the light intensity of the yellow fluorescence Ly generated by the phosphor 21 becomes higher. As a result, the color temperature of the white illumination light Lw, which is the composite light of the second light Lb2, which is a blue laser light, and the yellow fluorescence Ly, becomes lower.

[0061] 3 and 4, the temperature of the first light emitting element 11 and the temperature of the second light emitting element 12 are controlled using the temperature control element 90 to change the dominant wavelength of the first light Lb1 of the first light emitting element 11 and the dominant wavelength of the second light Lb2 of the second light emitting element 12. In this case, it is preferable to change the temperatures of the first light emitting element 11 and the second light emitting element 12 by 10° C. or more. In this embodiment, the temperatures of the first light emitting element 11 and the second light emitting element 12 are changed by changing the temperatures of the first light emitting element 11 and the second light emitting element 12 by 20° C.

[0062] Fig. 5 shows the emission spectra of each of the first light-emitting element 11 and the second light-emitting element 12 when Tc=20° C., 40° C., and 60° C. In Fig. 5, the first light-emitting element 11 and the second light-emitting element 12 are both blue semiconductor lasers that emit blue laser light.

[0063] As shown in Fig. 5, it can be seen that the dominant wavelength of the first light Lb1 of the first light emitting element 11 and the dominant wavelength of the second light Lb2 of the second light emitting element 12 both shift to the longer wavelength side as the temperature increases, and shift to the shorter wavelength side as the temperature decreases. Specifically, the dominant wavelength of the first light Lb1 of the first light emitting element 11 changes to 439.8 nm (Tc = 20 ° C), 441.2 nm (Tc = 40 ° C), and 442.9 nm (Tc = 60 ° C) as the temperature changes. In addition, the dominant wavelength of the second light Lb2 of the second light emitting element 12 changes to 454.5 nm (Tc = 20 ° C), 455.8 nm (Tc = 40 ° C), and 457.7 nm (Tc = 60 ° C) as the temperature changes. Furthermore, as shown in FIG. 5, the peak wavelengths of the first light-emitting element 11 and the second light-emitting element 12, which are semiconductor lasers, shift toward longer wavelengths as the temperature increases, and shift toward shorter wavelengths as the temperature decreases.

[0064] In FIG. 3, the temperature of only the first light-emitting element 11 of the first light-emitting element 11 and the second light-emitting element 12 is controlled, and in FIG. 4, the temperature of only the second light-emitting element 12 of the first light-emitting element 11 and the second light-emitting element 12 is controlled, but this is not limited thereto. Specifically, the main wavelength of the light source light Lb may be changed by controlling the temperatures of both the first light-emitting element 11 and the second light-emitting element 12. In this case, it is preferable to separate the heat sink 30, provide the first light-emitting element 11 and the second light-emitting element 12 in separate heat sinks 30, and provide a temperature control element 90 in each heat sink 30. This allows the temperature of the first light-emitting element 11 and the temperature of the second light-emitting element 12 to be individually controlled by each temperature control element 90.

[0065] Next, a description will be given of modifications of the lighting device 1. First, a lighting device 1A according to Modification 1 will be described with reference to Fig. 6. Fig. 6 is a diagram showing the configuration of the lighting device 1A according to Modification 1.

[0066] As shown in FIG. 6, the lighting device 1A according to this modification includes the phosphor 21 in the lighting device 1 described above as a first phosphor, and further includes a phosphor 23 as a second phosphor. Specifically, the phosphor section 20A of the lighting device 1A according to this modification includes the phosphor 21 and the phosphor 23. The phosphor 23 is excited by the light source light Lb from the light source section 10 and emits fluorescence Lr (second fluorescence) of a color different from the fluorescence Ly (first fluorescence) of the phosphor 23. Specifically, the fluorescence Ly emitted by the phosphor 21 is yellow, and the fluorescence Lr emitted by the phosphor 23 is red. As an example, the phosphor 23 emitting the red fluorescence Lr is a SCASN phosphor layer made of SCASN expressed by (Sr,Ca)AlSiN3:Eu. The phosphor 23 is, for example, stacked on the phosphor 21.

[0067] The excitation spectrum (absorption characteristics) and emission spectrum of phosphor 21 and phosphor 23 used in this modified example are shown in Fig. 7. In Fig. 7, phosphor 21 is a yellow phosphor layer made of YAG phosphor, and phosphor 23 is a red phosphor layer made of SCASN phosphor. As shown in Fig. 7, phosphors 21 and 23 both have high absorption characteristics for excitation light in the blue band (wavelengths 430 nm to 480 nm). The peak wavelength of fluorescence Ly of phosphor 21 is about 540 nm, and the peak wavelength of fluorescence Lr of phosphor 23 is about 630 nm.

[0068] In the illumination device 1A according to this modified example configured as above, a portion of the blue light source light Lb (Lb1, Lb2) incident on the phosphor section 20A serves as excitation light to excite the phosphor 21 and also excite the phosphor 23. This causes yellow fluorescence Ly and red fluorescence Lr to be emitted from the phosphor section 20A. Meanwhile, another portion of the blue light source light Lb (Lb1, Lb2) incident on the phosphor section 20A is transmitted through the phosphor section 20A. As a result, the illumination light of the illumination device 1A includes the blue light source light Lb (Lb1, Lb2), yellow fluorescence Ly, and red fluorescence Lr.

[0069] In this way, in the illumination device 1A according to this modification, a red component is added to the illumination light Lw of white light irradiated from the illumination device 1A, in comparison with the illumination light Lw in the above-described illumination device 1. This enables the illumination device 1A according to this modification to improve the color rendering of the illumination light Lw.

[0070] Note that the color adjustment control method using the lighting device 1A according to this modification can be performed in the same manner as the color adjustment control method using the lighting device 1 shown in Figures 2 and 3. That is, also in this modification, the chromaticity of the illumination light Lw is changed by changing the dominant wavelength of the light source light Lb emitted by the light source unit 10 to change the light intensity ratio between the light source light Lb of the light source unit 10 and the fluorescence Ly of the phosphor 21.

[0071] In this case, in this modification, the phosphor section 20A has not only phosphor 21 but also phosphor 23. As a result, by changing the dominant wavelength of the light source light Lb emitted by the light source section 10, the light intensity ratio between the light source light Lb of the light source section 10 and the fluorescence Lr of the phosphor 23 also changes, and the chromaticity of the illumination light Lw changes. Therefore, by using the lighting device 1A according to this modification, the color adjustment range can be expanded.

[0072] Here, the color adjustment range when the color adjustment control of the illumination light Lw is performed using the above-mentioned lighting device 1 and the lighting device 1A of this modified example will be described with reference to FIGS. 8 and 9. FIG.

[0073] Fig. 8 is an xy chromaticity diagram showing a change in chromaticity of the illumination light Lw when color adjustment control is performed using the lighting device 1 and a change in chromaticity of the illumination light Lw when color adjustment control is performed using the lighting device 1A. Fig. 9 shows the conditions when the color adjustment control of Fig. 8 is performed. Specifically, Fig. 9 shows the light intensity (light output) of the first light Lb1 which is a laser light emitted by the first light-emitting element 11, the light intensity (light output) of the second light Lb2 which is a laser light emitted by the second light-emitting element 12, the temperatures (Tc) of the first light-emitting element 11 and the second light-emitting element 12, and the dominant wavelength (composite dominant wavelength λd of Lb1 and Lb2) of the light source light Lb emitted by the light source unit 10.

[0074] In performing the color adjustment control of FIG. 8, the lighting device 1 shown in FIG. 1 to FIG. 4 and the lighting device 1A shown in FIG. 6 in which a phosphor 23 is added to the lighting device 1 were used. Specifically, the lighting device 1 includes a light source unit 10 having a first light-emitting element 11 (short wavelength LD) and a second light-emitting element 12 (long wavelength LD) that emit blue laser light, and a phosphor unit 20 having a phosphor 21 made of a YAG phosphor. The lighting device 1A includes a light source unit 10 having a first light-emitting element 11 (short wavelength LD) and a second light-emitting element 12 (long wavelength LD) that emit blue laser light, and a phosphor unit 20A having a phosphor 21 made of a YAG phosphor and a phosphor 23 made of a SCASN phosphor.

[0075] Then, for each of the lighting devices 1 and 1A, the chromaticity of the illumination light Lw was obtained when the temperatures (Tc) of the first light-emitting element 11 and the second light-emitting element 12 were individually controlled by the temperature control element 90 to 20° C., 40° C., and 60° C. in the cases of stopping the optical output of the second light-emitting element 12 and causing only the first light-emitting element 11 to emit light, stopping the optical output of the first light-emitting element 11 and causing only the second light-emitting element 12 to emit light, and causing both the first light-emitting element 11 and the second light-emitting element 12 to emit light. Note that, as shown in FIG. 9, the total amount of optical output (energy) of the light source light Lb of the light source unit 10 irradiating the phosphor unit 20 and the phosphor unit 20A was constant in all cases.

[0076] The results are shown in Fig. 8. As shown in Fig. 8, in either case, it is understood that the chromaticity of the illumination light Lw emitted from the lighting devices 1 and 1A can be changed. Specifically, the color temperature of the illumination light Lw, which is white light, can be changed. In this way, even when the first light-emitting element 11 and the second light-emitting element 12 that emit the same blue laser light are used, it is possible to perform color adjustment control of the lighting devices 1 and 1A.

[0077] Furthermore, as shown in FIG. 8, the first light-emitting element 11 emitting a laser beam with a short wavelength has a wider color gamut than the second light-emitting element 12 emitting a laser beam with a long wavelength, and it is found that the color tuning range by temperature control can be widened.

[0078] Furthermore, as can be seen by comparing the chromaticity of the illumination light Lw of the illumination device 1 with the chromaticity of the illumination light Lw of the illumination device 1A, it is understood that the color tuning range can be expanded by adding the phosphor 23 that emits red fluorescence Lr.

[0079] In particular, phosphor 23 in this embodiment has a higher absorption rate for short-wavelength excitation light than phosphor 21, as shown in Fig. 7. In other words, the shorter the wavelength of the excitation light, the greater the amount of fluorescence Lr emitted from phosphor 23. For this reason, in the illumination device 1A using phosphor 21 that emits yellow fluorescence Ly and phosphor 23 that emits red fluorescence Lr, the shorter the wavelength of the blue laser light that is the excitation light, the higher the ratio of fluorescence Lr emitted by phosphor 23 and the greater the ratio of red fluorescence Lr.

[0080] As a result, as shown in the emission spectrum in Fig. 10, when only the first light-emitting element 11 emitting a short wavelength laser light is made to emit light (dotted line in Fig. 10), it is found that the ratio of wavelength components on the red wavelength side is increased around the wavelength of 600 nm, compared to when only the second light-emitting element 12 emitting a long wavelength laser light is made to emit light (solid line in Fig. 10). Note that Fig. 10 shows the emission spectrum of the phosphor section 20A at Tc=20°C in the lighting device 1A including the phosphor section 20A having the phosphor 21 made of a YAG phosphor and the phosphor 23 made of a SCASN phosphor.

[0081] It can also be seen that the spectrum of the fluorescence emitted from the phosphor section 20A can be changed by using two types of phosphors, phosphor 21 made of a YAG phosphor and phosphor 23 made of a SCASN phosphor, as shown in Fig. 10. It can also be seen that even when two types of phosphors are used, the luminous efficiency (conversion efficiency) of phosphors 21 and 23 combined increases as the wavelength of the excitation light increases, as shown in Fig. 10.

[0082] Next, an illumination device 1B according to Modification 2 will be described with reference to Fig. 11. Fig. 11 is a diagram showing the configuration of an illumination device 1B according to Modification 2.

[0083] 11, an illumination device 1B according to this modification has the light source unit 10 in the illumination device 1 described above as a main light source unit, and further includes an auxiliary light source unit 10B that emits auxiliary light source light Lc of a color different from the color of the light source light Lb that is the main light source light, when the light source unit 10 is used as the main light source light. The auxiliary light source unit 10B has a third light-emitting element 13 that emits a third light Lc3. The color of the third light Lc3 emitted by the third light-emitting element 13 is different from the colors of the first light Lb1 emitted by the first light-emitting element 11 and the second light Lb2 emitted by the second light-emitting element 12.

[0084] In this modification, the third light-emitting element 13 is a red semiconductor laser that emits red laser light. In addition, in this modification, the auxiliary light source unit 10B is composed of only the third light-emitting element 13. Therefore, the auxiliary light source light Lc emitted by the auxiliary light source unit 10B is the same as the third light Lc3 emitted by the third light-emitting element 13 (Lc=Lc3). Note that the auxiliary light source unit 10B may have a light-emitting element other than the third light-emitting element 13.

[0085] In this modification, the illumination light of the illumination device 1B includes blue source light Lb (Lb1, Lb2), yellow fluorescence Ly, and red third light Lc3.

[0086] In this way, in the illumination device 1B according to this modification, a red component is added to the illumination light Lw of white light emitted from the illumination device 1B compared to the illumination light Lw in the above-described illumination device 1. This enables the illumination device 1B according to this modification to improve the color rendering of the illumination light Lw.

[0087] Note that the color adjustment control method using the lighting device 1B according to this modification can be performed in the same manner as the color adjustment control method using the lighting device 1 shown in Figures 2 and 3. That is, also in this modification, the chromaticity of the illumination light Lw is changed by changing the light intensity ratio between the light source light Lb of the light source unit 10 and the fluorescence Ly of the phosphor 21 by changing the dominant wavelength of the light source light Lb emitted by the light source unit 10 (main light source unit).

[0088] In this case, in this modification, the illumination light Lw of the lighting device 1B contains the third light Lc3 of red in addition to the blue light source light Lb (Lb1+Lb2) and the yellow fluorescence Ly. This allows the lighting device 1B according to this modification to have an expanded color tuning range.

[0089] As described above, the lighting devices 1, 1A and 1B according to the present embodiment include a first light-emitting element 11 that emits a first light Lb1, a second light-emitting element 12 that emits a second light Lb2 that has the same color gamut as the first light Lb1 but a different dominant wavelength from the first light Lb1, and a phosphor 21 that emits fluorescence Ly. The dominant wavelength of the light source light Lb emitted by the light source unit 10 is changed to change the light intensity ratio between the light source light Lb and the fluorescence Ly, thereby changing the chromaticity of the illumination light Lw.

[0090] As a result, the lighting devices 1, 1A, and 1B according to the present embodiment can change the chromaticity of the illumination light Lw even though they use multiple light-emitting elements that emit light of the same color gamut. Therefore, a lighting device that can perform not only dimming control but also color adjustment control can be realized with a simple configuration.

[0091] (Modification) Although the lighting device according to the present invention has been described based on the embodiment, the present invention is not limited to the above embodiment.

[0092] For example, in the above embodiment, the light source light Lb emitted by the light source unit 10 is blue light, and the excitation light incident on the phosphor units 20 and 20A is blue light, but this is not limited thereto. Specifically, the excitation light incident on the phosphor units 20 and 20A may be ultraviolet light having a shorter wavelength than blue light. In this case, the first light-emitting element 11 and the second light-emitting element 12 constituting the light source unit 10 may be semiconductor lasers that emit ultraviolet laser light. Even in this case, the first light-emitting element 11 and the second light-emitting element 12 emit ultraviolet light in the same color gamut. Note that if the wavelength range is at least within 40 nm, it can be said that they have the same color gamut.

[0093] Furthermore, in the above-described embodiments, the lighting devices 1, 1A, and 1B can be used in various products such as projectors, floodlights, endoscopes, vehicle headlamps, or lighting fixtures.

[0094] In addition, the present disclosure also includes forms obtained by applying various modifications to the above-mentioned embodiments that a person skilled in the art may conceive, and forms realized by arbitrarily combining the components and functions of the embodiments within the scope of the present disclosure. In addition, the present disclosure also includes any combination of two or more claims from among the multiple claims described in the claims at the time of filing of the present application, within the scope of technical compatibility. For example, when a cited-form claim described in the claims at the time of filing of the present application is made into a multiple claim or multiple multiple claim so as to cite all of the higher claims within the scope of technical compatibility, the present disclosure also includes a combination of all claims included in the multiple claim or multiple multiple claim. [Explanation of symbols]

[0095] 1, 1A, 1B lighting equipment 10 Light source section (main light source section) 10B Sub-light source section 11 First light emitting element 12 Second light emitting element 13 Third light-emitting element 20, 20A Phosphor unit 21, 23 Phosphors 90 Temperature control element Lw lighting light Lb light source light (main light source light) Lc sub-light source light Lb1 First Light Lb2 Second Light Lc3 The third light Ly, Lr fluorescence

Claims

1. An illumination device that emits illumination light, A light source unit that emits light source light; a first phosphor that is excited by the light source light to emit a first fluorescent light, the light source unit includes a first light-emitting element that emits a first light, and a second light-emitting element that emits a second light having the same color gamut as the first light and a dominant wavelength different from that of the first light, the source light includes at least one of the first light and the second light, the illumination light is a composite light of the light source light and the first fluorescent light, changing a dominant wavelength of the light source light to change a light intensity ratio between the light source light and the first fluorescent light, thereby changing the chromaticity of the illumination light; Lighting equipment.

2. A light intensity ratio between the first light and the second light is changed to change a dominant wavelength of the light source light.

10. The lighting device of claim 1.

3. a temperature control element that controls a temperature of one of the first light emitting element and the second light emitting element; a temperature control element is used to change a temperature of one of the first light-emitting element and the second light-emitting element, and a dominant wavelength of the light source light is changed by changing the temperature of one of the first light-emitting element and the second light-emitting element using the temperature control element in a state where the light output of the other of the first light-emitting element and the second light-emitting element is stopped; 10. The lighting device of claim 1.

4. a second phosphor that is excited by the light source light to emit a second fluorescent light having a color different from the first fluorescent light; The illumination light further includes the second fluorescent light. The lighting device according to any one of claims 1 to 3.

5. the light source unit is a main light source unit, and when the light source light is the main light source light, an auxiliary light source unit is further provided which emits an auxiliary light source light of a color different from the color of the main light source light, the auxiliary light source unit has a third light emitting element that emits a third light having a color different from the first light and the second light, The illumination light further includes the third light. The lighting device according to any one of claims 1 to 3.

6. The first light emitting element and the second light emitting element are constituted by semiconductor lasers. The lighting device according to any one of claims 1 to 3.

7. the first light and the second light are blue in color; The first fluorescence is yellow. The lighting device according to any one of claims 1 to 3.

8. If the difference between the dominant wavelength of the first light and the dominant wavelength of the second light is Δλ [nm], 0<Δλ≦40; The lighting device according to any one of claims 1 to 3.

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