Illumination system and illumination method

Abstract

To provide an illumination system and an illumination method capable of realizing output light having a high general color rendering index Ra and adjusting the chromaticity of the output light.SOLUTION: An illumination system realizes output light having a chromaticity value in a triangular area a (area 1a, area 2a, or area 3a) whose vertexes are two points out of point B indicating the chromaticity value of light emitted by a blue light source, a point G indicating the chromaticity value of light emitted by a green light source, and a point R indicating the chromaticity value of light emitted by a red light source, and a point W indicating the chromaticity value of light emitted by a white light source by causing two light sources corresponding to two points among the blue light source, the green light source, and the red light source, and the white light source to emit light.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a lighting system and a lighting method.

Background Art

[0002] Conventionally, various techniques for adjusting the hue of the output light of a lighting device have been proposed (see, for example, Patent Document 1).

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention provides a lighting system and a lighting method capable of adjusting the chromaticity of output light and realizing output light having a high average color rendering evaluation number Ra.

Means for Solving the Problems

[0005] The lighting system according to one aspect of the present invention includes a first light source that emits light having a first chromaticity value, a second light source that emits light having a second chromaticity value, a third light source that emits light having a third chromaticity value, and a control unit that controls a fourth light source that emits light having a fourth chromaticity value. On the chromaticity coordinates, the triangular region with the points indicating the first chromaticity value, the points indicating the second chromaticity value, and the points indicating the third chromaticity value as vertices encloses the chromaticity range of the light source color defined in JIS Z9112. On the chromaticity coordinates, the point indicating the fourth chromaticity value is located within the chromaticity range. The control unit realizes output light having a chromaticity value within a triangular region a with two of the points indicating the first chromaticity value, the points indicating the second chromaticity value, and the points indicating the third chromaticity value, and the point indicating the fourth chromaticity value as vertices, by causing the two light sources corresponding to the two points among the first light source, the second light source, and the third light source, and the fourth light source to emit light.

[0006] The lighting method according to one aspect of the present invention includes a control step of controlling a first light source that emits light having a first chromaticity value, a second light source that emits light having a second chromaticity value, a third light source that emits light having a third chromaticity value, and a fourth light source that emits light having a fourth chromaticity value. On the chromaticity coordinates, the triangular region with the points indicating the first chromaticity value, the points indicating the second chromaticity value, and the points indicating the third chromaticity value as vertices encloses the chromaticity range of the light source color defined in JIS Z9112. On the chromaticity coordinates, the point indicating the fourth chromaticity value is located within the chromaticity range. In the control step, output light having a chromaticity value within a triangular region a with two of the points indicating the first chromaticity value, the points indicating the second chromaticity value, and the points indicating the third chromaticity value, and the point indicating the fourth chromaticity value as vertices, is realized by causing the two light sources corresponding to the two points among the first light source, the second light source, and the third light source, and the fourth light source to emit light.

[0007] The program according to one aspect of the present invention is a program for causing a computer to execute the lighting method.

Effects of the Invention

[0008] According to the present invention, there are provided an illumination system and an illumination method capable of adjusting the chromaticity of output light and realizing output light having a high average color rendering evaluation number Ra.

Brief Description of Drawings

[0009]

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[0010] Hereinafter, embodiments will be specifically described with reference to the drawings. Note that the embodiments described below are all examples showing comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps, order of steps, etc. shown in the following embodiments are merely examples and are not intended to limit the present invention. In addition, among the components in the following embodiments, the components not described in the independent claims are described as optional components.

[0011] Note that each figure is a schematic diagram and is not necessarily drawn precisely. Also, in each figure, the same reference numerals are given to substantially the same configurations, and redundant descriptions may be omitted or simplified.

[0012] (Embodiment) [Configuration] First, the configuration of the lighting system according to the embodiment will be described. FIG. 1 is a block diagram showing the functional configuration of the lighting system according to the embodiment.

[0013] The lighting system 10 is a system that can make the lighting device 40 emit light at a desired chromaticity of the user by independently dimming the blue light source 42b, green light source 42g, red light source 42r, and white light source 42w included in the light source unit 42 provided in the lighting device 40. That is, the lighting system 10 is a system corresponding to the chromaticity adjustment function of the lighting device 40. The lighting system 10 includes an input device 20, a control device 30, and a lighting device 40. Note that the lighting system 10 may include a plurality of lighting devices 40 for one control device 30.

[0014] The input device 20 receives an input for specifying chromaticity from the user. The input device 20 is, for example, a portable information terminal such as a smartphone or a tablet terminal, but may also be a stationary information terminal fixedly installed on a wall or the like. The input device 20 may be realized by installing an application program corresponding to the lighting system 10 in a general-purpose device, or may be a dedicated device of the lighting system 10.

[0015] The control device 30 performs control to make the lighting device 40 emit light at the chromaticity input to the input device 20. The control device 30 includes a control unit 31 and a storage unit 32. Note that the input device 20 and the control device 30 may be realized as an integrated single device.

[0016] The control unit 31 controls the light emission of the lighting device 40. Specifically, the control unit 31 can adjust the chromaticity of the light emitted by the lighting device 40 by transmitting a control signal to the lighting device 40. The control unit 31 transmits a control signal to the lighting device 40, for example, by wireless communication, but may also transmit a control signal to the lighting device 40 by wired communication. The control unit 31 is realized by, for example, a microcomputer, but may also be realized by a processor. The function of the control unit 31 is realized by the microcomputer or processor constituting the control unit 31 executing a computer program stored in the storage unit 32.

[0017] The storage unit 32 is a storage device that stores the computer program executed by the control unit 31 and various information necessary for controlling the lighting device 40. Specifically, the storage unit 32 is realized by a semiconductor memory or the like.

[0018] The lighting device 40 is installed indoors, for example, and illuminates the indoor space. The lighting device 40 is, for example, a ceiling light, but may be other lighting devices such as a spotlight or a downlight. The lighting device 40 includes a dimming circuit 41 and a light source unit 42. The light source unit 42 includes a red light source 42r, a green light source 42g, a blue light source 42b, and a white light source 42w.

[0019] The dimming circuit 41 is a circuit that supplies power to the light source unit 42 according to a control signal transmitted from the control device 30 (control unit 31). The dimming circuit 41 includes, for example, a chopper control circuit. The control unit 31 changes the current supplied to the light source unit 42 by switching the switching element included in the dimming circuit 41 (chopper control circuit) with a control signal. Note that the dimming circuit 41 can supply power (current) independently to each of the light sources of the blue light source 42b, the green light source 42g, the red light source 42r, and the white light source 42w included in the light source unit 42. That is, the dimming circuit 41 can independently dim the red light source 42r, the green light source 42g, the blue light source 42b, and the white light source 42w included in the light source unit 42.

[0020] The blue light source 42b is a light source that emits blue light and is an example of the first light source. The blue light source 42b emits blue light (specifically, including blue and purple light) having an emission peak wavelength of 380 nm or more and 480 nm or less, for example. The blue light emitted by the blue light source 42b has, for example, an emission spectrum as shown in FIG. 2. FIG. 2 is a diagram showing an example of the emission spectrum of the blue light source 42b (green light source 42g, red light source 42r). Specifically, the blue light source 42b is a light emitting module using a blue LED, but the specific form of the blue light source 42b is not particularly limited.

[0021] The green light source 42g is a light source that emits green light and is an example of the second light source. The green light source 42g emits, for example, green light with an emission peak wavelength of 480 nm or more and 580 nm or less (specifically, including cyan-green, blue-green, green, and yellow-green light). The green light emitted by the green light source 42g has, for example, an emission spectrum as shown in FIG. 2. Specifically, the green light source 42g is a light-emitting module using a green LED, but the specific form of the green light source 42g is not particularly limited.

[0022] The red light source 42r is a light source that emits red light and is an example of the third light source. The red light source 42r emits, for example, red light with an emission peak wavelength of 600 nm or more and 680 nm or less. The red light emitted by the red light source 42r has, for example, an emission spectrum as shown in FIG. 2. Specifically, the red light source 42r is a light-emitting module using a red LED, but the specific form of the red light source 42r is not particularly limited.

[0023] The white light source 42w is a light source that emits white light and is an example of the fourth light source. FIG. 3 is a diagram showing an example of the emission spectrum of the white light emitted by the white light source 42w. In FIG. 3, the emission spectra when the color temperature of the white light emitted by the white light source 42w is 2700 K, 3500 K, and 6500 K are respectively shown. Note that the chromaticity value of the white light emitted by the white light source 42w only needs to be within the chromaticity range of the light source color defined in JIS Z9112, and it may be white on the blackbody locus or white outside the blackbody locus.

[0024] Specifically, the white light source 42w is a COB (Chip On Board) type light-emitting module or an SMD (Surface Mount Device) type light-emitting module. Also, the white light source 42w may be a remote phosphor type light-emitting module.

[0025] [Example of chromaticity control 1] When controlling the chromaticity of the output light of the lighting device 40, the lighting system 10 can improve the color rendering property of the output light by selectively emitting light from the blue light source 42b, the green light source 42g, the red light source 42r, and the white light source 42w. Note that the output light is light obtained by combining at least one of the light emitted by the red light source 42r, the light emitted by the green light source 42g, the light emitted by the blue light source 42b, and the light emitted by the white light source 42w, and means the light finally emitted from the lighting device 40. Hereinafter, a control example 1 of the chromaticity of the lighting system 10 will be described with reference to a chromaticity diagram (chromaticity coordinates). FIG. 4 is a diagram showing chromaticity coordinates in which the chromaticity values of the red light source 42r, the green light source 42g, the blue light source 42b, and the white light source 42w are plotted. The chromaticity coordinates in FIG. 4 show a color space defined in CIE1931.

[0026] In the chromaticity coordinates of FIG. 4, a point B indicating the first chromaticity value of the blue light emitted by the blue light source 42b, a point G indicating the second chromaticity value of the green light emitted by the green light source 42g, a point R indicating the third chromaticity value of the red light emitted by the red light source 42r, and a point W indicating the fourth chromaticity value of the white light emitted by the white light source 42w are shown.

[0027] On the chromaticity coordinates, the triangular region with points B, G, and R as vertices encloses the chromaticity range of the light source color defined in JIS Z9112. Here, the light source color means five types: daylight color (D), day white (N), white (W), warm white (WW), and bulb color (L), and the chromaticity ranges of the five types of light source colors are five substantially parallelogram regions near the blackbody locus in FIG. 4. Also, the triangular region with points B, G, and R as vertices encloses point W. The lighting system 10 can realize output light having a chromaticity value within the triangular region with points B, G, and R as vertices, and it can be said that the chromaticity range of the output light that the lighting system 10 can realize is relatively wide.

[0028] Here, the triangular region with points B, G, and R as vertices includes three regions: region 1a, region 2a, and region 3a. Region 1a is a triangular region with points G, R, and W as vertices, region 2a is a triangular region with points B, G, and W as vertices, and region 3a is a triangular region with points B, R, and W as vertices.

[0029] For example, when the point indicating the chromaticity value desired by the user input to the input device 20 is located within region 1a, the control unit 31 of the control device 30 emits the three light sources, namely the green light source 42g, the red light source 42r, and the white light source 42w, without emitting the blue light source 42b, and realizes output light having the chromaticity value desired by the user by independently dimming the light sources. Similarly, when the point indicating the chromaticity value desired by the user input to the input device 20 is located within region 2a, the control unit 31 of the control device 30 emits the three light sources, namely the blue light source 42b, the green light source 42g, and the white light source 42w, without emitting the red light source 42r, and realizes output light having the chromaticity value desired by the user by independently dimming the light sources. When the point indicating the chromaticity value desired by the user input to the input device 20 is located within region 3a, the control unit 31 of the control device 30 emits the three light sources, namely the blue light source 42b, the red light source 42r, and the white light source 42w, without emitting the green light source 42g, and realizes output light having the chromaticity value desired by the user by independently dimming the light sources.

[0030] Hereinafter, the average color rendering evaluation number Ra of the output light obtained by such a chromaticity control method will be described while comparing it with the average color rendering evaluation number Ra of the output light obtained by the chromaticity control method according to the comparative example. FIGS. 5 to 7 are diagrams showing the average color rendering evaluation number Ra and the special color rendering evaluation number R9 of the output light obtained by the chromaticity control method (hereinafter, also simply referred to as control example 1) in the lighting system 10.

[0031] In addition, in FIGS. 5 to 7, the average color rendering evaluation number Ra and the special color rendering evaluation number R9 of the output light obtained by the color control method according to the comparative example are also shown. The color control method according to the comparative example is a control method that realizes output light having a chromaticity value desired by the user by emitting three light sources, namely, a blue light source 42b, a green light source 42g, and a red light source 42r, without emitting a white light source 42w, and independently dimming them. In FIGS. 5 to 7, the output light is white light, and the average color rendering evaluation number Ra and the special color rendering evaluation number R9 of the output light are shown respectively when Duv = 0 and when Duv = 3. In FIGS. 5 to 7, the horizontal axis represents the color temperature (Tc) of the output light, and the vertical axis represents the average color rendering evaluation number Ra or the special color rendering evaluation number R9 of the output light.

[0032] FIG. 5 shows the average color rendering evaluation number Ra and the special color rendering evaluation number R9 respectively when, according to Control Example 1, output light is realized using a red light source 42r, a green light source 42g, and a white light source 42w (RGL in FIG. 5), and when, according to Control Example 1, output light is realized using a white light source 42w, a green light source 42g, and a blue light source 42b (LGB in FIG. 5), when the color temperature of the white light source 42w is 2700K (bulb color: L). In FIG. 5, the average color rendering evaluation number Ra and the special color rendering evaluation number R9 when output light is realized by a red light source 42r, a green light source 42g, and a blue light source 42b (RGB in FIG. 5) according to the comparative example are also shown.

[0033] FIG. 6 shows the average color rendering evaluation number Ra and the special color rendering evaluation number R9 respectively when, according to Control Example 1, output light is realized using a red light source 42r, a green light source 42g, and a white light source 42w (RGWW in FIG. 6), and when, according to Control Example 1, output light is realized using a white light source 42w, a green light source 42g, and a blue light source 42b (WWGB in FIG. 6), when the color temperature of the white light source 42w is 3500K (warm white: WW). In FIG. 6, the average color rendering evaluation number Ra and the special color rendering evaluation number R9 when output light is realized by a red light source 42r, a green light source 42g, and a blue light source 42b (RGB in FIG. 6) according to the comparative example are also shown.

[0034] FIG. 7 shows the average color rendering evaluation number Ra and the special color rendering evaluation number R9 when output light is realized using the red light source 42r, the green light source 42g, and the white light source 42w according to Control Example 1 (RGD in FIG. 7), and when output light is realized using the white light source 42w, the green light source 42g, and the blue light source 42b according to Control Example 1 (DGB in FIG. 7), when the color temperature of the white light source 42w is 6500K (daylight white: D). In FIG. 7, the average color rendering evaluation number Ra and the special color rendering evaluation number R9 when output light is realized by the red light source 42r, the green light source 42g, and the blue light source 42b according to the comparative example (RGB in FIG. 7) are also shown together.

[0035] As shown in FIGS. 5 to 7, according to Control Example 1, output light having a higher average color rendering evaluation number Ra and special color rendering evaluation number R9 than the comparative example can be realized. The emission spectra obtained by Control Example 1 and the emission spectra obtained by the comparative example are shown in FIGS. 8 and 9. FIG. 8 is a diagram showing the emission spectrum when output light having a color temperature of 2700K and Duv = 0 is realized by using the red light source 42r, the green light source 42g, and the white light source 42w having a color temperature of 3500K according to Control Example 1. FIG. 9 is a diagram showing the emission spectrum when output light having a color temperature of 2700K and Duv = 0 is realized by using the red light source 42r, the green light source 42g, and the blue light source 42b according to the comparative example.

[0036] As described above, in the lighting system 10, the control unit 31 realizes output light having a chromaticity value within the triangular region a (region 1a, region 2a, or region 3a) by causing two of the blue light source 42b, the green light source 42g, and the blue light source 42b and the white light source 42w to emit light. Thereby, the lighting system 10 can realize output light having a high average color rendering evaluation number Ra and special color rendering evaluation number R9. The lighting system 10 can improve the average color rendering evaluation number Ra of output light having a light source color (any of five types) defined in JIS Z9112, for example, and reduce color unevenness on the light irradiation surface.

[0037] Also, according to Control Example 1, there may be a case where the maximum light amount (brightness) of the output light can be increased compared to the Comparative Example. FIG. 10 is a diagram showing the maximum luminous flux of the output light obtained by the chromaticity control method (Control Example 1) in the illumination system 10.

[0038] FIG. 10 shows the case where, when the color temperature of the white light source 42w is 3500K (warm white: WW), the output light with Duv = 0 is realized using the red light source 42r, the green light source 42g, and the white light source 42w according to Control Example 1 (RGWW in FIG. 10), and also the case where the output light with Duv = 0 is realized using the white light source 42w, the green light source 42g, and the blue light source 42b according to Control Example 1 (WWGB in FIG. 10), respectively showing the maximum luminous fluxes. In FIG. 10, the maximum luminous flux in the case where the output light with Duv = 0 is realized by the red light source 42r, the green light source 42g, and the blue light source 42b according to the Comparative Example (RGB in FIG. 10) is also shown. As shown in FIG. 10, if the output light is realized using the red light source 42r, the green light source 42g, and the white light source 42w, the maximum light amount (brightness) of the output light can be significantly increased compared to the Comparative Example.

[0039] [Control Example 2] The chromaticity control example 2 of the illumination system 10 will be described with reference to the chromaticity diagram (chromaticity coordinates). FIG. 11 is a diagram showing the chromaticity coordinates on which the boundary points related to Control Example 2 are plotted. The chromaticity coordinates in FIG. 11 show the color space defined in CIE1931. The chromaticity coordinates in FIG. 11 are basically the same as those in FIG. 4, but the points where the boundary points B1, boundary point G1, and boundary point R1 are shown are different.

[0040] The boundary point B1 is a point located on the line segment connecting the point B and the point W. In FIG. 11, the boundary point B1 is a point showing the chromaticity value when the blue light source 42b corresponding to the point B and the white light source 42w corresponding to the point W emit light with the maximum brightness, but it is a point located on the line segment connecting the point B and the point W, and any point located between the point B and the point W (points other than the point B and the point W) is acceptable.

[0041] The boundary point G1 is a point located on the line segment connecting point G and point W. In FIG. 11, the boundary point G1 is a point indicating the chromaticity values when the green light source 42g corresponding to point G and the white light source 42w corresponding to point W emit light at maximum brightness, but it is a point located on the line segment connecting point G and point W, and any point located between point G and point W (points other than point G and point W) is acceptable.

[0042] The boundary point R1 is a point located on the line segment connecting point R and point W. In FIG. 11, the boundary point R1 is a point indicating the chromaticity values when the red light source 42r corresponding to point R and the white light source 42w corresponding to point W emit light at maximum brightness, but it is a point located on the line segment connecting point R and point W, and any point located between point R and point W (points other than point R and point W) is acceptable.

[0043] In the above control example 1, the chromaticity values within the triangular region with points B, G, and R as vertices were realized by causing two of the blue light source 42b, green light source 42g, and red light source 42r, and the white light source 42w to emit light. Here, the chromaticity values within the triangular region with the boundary point B1, boundary point G1, and boundary point R1 as vertices can also be realized by causing all of the blue light source 42b, green light source 42g, red light source 42r, and white light source 42w to emit light. By doing so, it is possible to achieve both an improvement in the average color rendering evaluation number Ra of the output light and an increase in the light quantity of the output light. Therefore, in control example 2, the control unit 31 realizes the chromaticity values within the triangular region with the boundary point B1, boundary point G1, and boundary point R1 as vertices by causing all of the blue light source 42b, green light source 42g, red light source 42r, and white light source 42w to emit light and independently dimming them.

[0044] In the triangular region with boundary points B1, G1, and R1 as vertices, more specifically, there are included a triangular region 1b with boundary points G1, R1, and point W as vertices, a triangular region 2b with boundary points B1, G1, and point W as vertices, and a triangular region 3b with boundary points B1, R1, and point W as vertices. Region 1b is a partial region near point W within region 1a, region 2b is a partial region near point W within region 2a, and region 3b is a partial region near point W within region 3a.

[0045] The control unit 31 realizes, for example, output light having a certain chromaticity value within the above-mentioned region 1b as follows. The control unit 31 calculates the first dimming value of each light source when realizing the chromaticity value within region 1b by emitting light from the green light source 42g, the red light source 42r, and the white light source 42w without emitting light from the blue light source 42b. Also, the control unit 31 calculates the second dimming value of each light source when realizing the chromaticity value within region 1b by emitting light from the blue light source 42b, the green light source 42g, and the red light source 42r without emitting light from the white light source 42w. By setting the dimming value obtained by summing the first dimming value and the second dimming value as the final dimming value, the control unit 31 can achieve both an improvement in the average color rendering evaluation number Ra and an increase in the light quantity of the output light having the chromaticity value within region 1b.

[0046] Also, the control unit 31 realizes, for example, output light having a certain chromaticity value within the above-mentioned region 2b as follows. The control unit 31 calculates the third dimming value of each light source when realizing the chromaticity value within region 2b by emitting light from the blue light source 42b, the green light source 42g, and the white light source 42w without emitting light from the red light source 42r. Also, the control unit 31 calculates the fourth dimming value of each light source when realizing the chromaticity value within region 2b by emitting light from the blue light source 42b, the green light source 42g, and the red light source 42r without emitting light from the white light source 42w. By setting the dimming value obtained by summing the third dimming value and the fourth dimming value as the final dimming value, the control unit 31 can achieve both an improvement in the average color rendering evaluation number Ra and an increase in the light quantity of the output light having the chromaticity value within region 2b.

[0047] Further, the control unit 31 realizes output light having a certain chromaticity value within the above-mentioned region 3b as follows. The control unit 31 calculates the fifth dimming value of each light source when realizing the chromaticity value within the region 3b by emitting the blue light source 42b, the red light source 42r, and the white light source 42w without emitting the green light source 42g. Also, the control unit 31 calculates the sixth dimming value of each light source when realizing the chromaticity value within the region 3b by emitting the blue light source 42b, the green light source 42g, and the red light source 42r without emitting the white light source 42w. By setting the dimming value obtained by summing the fifth dimming value and the sixth dimming value as the final dimming value, the control unit 31 can achieve both an improvement in the average color rendering evaluation number Ra and an increase in the light amount of the output light having the chromaticity value within the region 3b.

[0048] Note that in regions 1b, 2b, and 3b, it may be switched whether to apply control example 1 or control example 2. For example, the control unit 31 may selectively execute the operation in the color rendering priority mode that emphasizes the color rendering property of the output light having the chromaticity value belonging to regions 1b, 2b, and 3b and the operation in the light amount priority mode that emphasizes the light amount of the output light having the chromaticity value belonging to regions 1b, 2b, and 3b. In the operation in the color rendering priority mode, as described in control example 1, the control unit 31 realizes the chromaticity value belonging to regions 1b, 2b, and 3b by emitting two of the blue light source 42b, the green light source 42g, and the red light source 42r and the white light source 42w. In the operation in the light amount priority mode, as described in control example 2, the control unit 31 realizes the chromaticity value belonging to regions 1b, 2b, and 3b by emitting the blue light source 42b, the green light source 42g, the red light source 42r, and the white light source 42w. The color rendering priority mode is an example of the first mode, and the light amount priority mode is an example of the second mode. Such switching of the operation mode is performed, for example, based on the user's input to the input device 20.

[0049] [Modification Example] In the above embodiment, the blue light emitted by the blue light source 42b, the green light emitted by the green light source 42g, and the red light emitted by the red light source 42r are realized by the emitted light of the LED. Here, the green light emitted by the green light source 42g and the red light emitted by the red light source 42r may be realized by the fluorescence emitted by the phosphor.

[0050] In this case, each of the green light source 42g and the red light source 42r includes, for example, an excitation light source realized by a blue LED or the like, and a phosphor-containing resin that seals the excitation light source. The phosphor constituting the green light source 42g is Y 3 (Al,Ga) 5 O 12 :Ce phosphor or the like, which is a yttrium aluminum garnet (YAG) - based green phosphor, but it may also be a lutetium aluminum garnet (LuAG) - based green phosphor such as Lu 3 Al 5 O 12 :Ce phosphor. The phosphor constituting the red light source 42r is a red phosphor such as CaAlSiN 3 :Eu phosphor or (Sr,Ca)AlSiN 3 :Eu phosphor. FIG. 12 is a diagram showing an example of the emission spectra of the blue light source 42b according to such a modified example, the green light source 42g according to the modified example, and the red light source 42r according to the modified example.

[0051] As shown in FIG. 12, the emission spectra of the green light source 42g according to the modified example and the red light source 42r according to the modified example have a shape with a wider tail compared to the emission spectra of the green light source 42g according to the above-described embodiment and the red light source 42r according to the above-described embodiment (FIG. 4). The half-value widths of the emission spectra of the green light source 42g according to the above-described embodiment and the red light source 42r according to the above-described embodiment are about 20 nm (10 nm or more and 30 nm or less), while the half-value widths of the emission spectra of the green light source 42g according to the modified example and the red light source 42r according to the modified example are 60 nm or more and 100 nm or less. Note that the blue light source 42b according to the modified example is realized by an LED in the same manner as the blue light source 42b according to the above-described embodiment, and the half-value width of the emission spectrum of the blue light source 42b according to the modified example is about 20 nm (10 nm or more and 30 nm or less).

[0052] Hereinafter, the average color rendering evaluation number Ra of the output light obtained by applying Control Example 1 to the three-color light sources according to these modified examples will be described while comparing it with the average color rendering evaluation number Ra of the output light obtained by applying the chromaticity control method according to the comparative example to the three-color light sources according to the modified examples. FIGS. 13 to 15 are diagrams showing the average color rendering evaluation number Ra of the output light obtained by the chromaticity control method (Control Example 1) in the lighting system 10 according to the modified example (the lighting system 10 including the three-color light sources according to the modified example).

[0053] Note that in FIGS. 13 to 15, the output light is white light, and the average color rendering evaluation number Ra of the output light is shown for each of when Duv = 0 and when Duv = 3. In FIGS. 13 to 15, the horizontal axis indicates the color temperature of the output light, and the vertical axis indicates the average color rendering evaluation number Ra of the output light.

[0054] FIG. 13 shows the average color rendering evaluation number Ra for each case where output light is realized using the red light source 42r according to the modified example, the green light source 42g according to the modified example, and the white light source 42w (RGL in FIG. 13) and the case where output light is realized using the white light source 42w, the green light source 42g according to the modified example, and the blue light source 42b according to the modified example (LGB in FIG. 13) by Control Example 1 when the color temperature of the white light source 42w is 2700K (incandescent color: L). In FIG. 13, the average color rendering evaluation number Ra for the case where output light is realized by the red light source 42r according to the modified example, the green light source 42g according to the modified example, and the blue light source 42b according to the modified example (RGB in FIG. 13) by the comparative example is also shown together.

[0055] FIG. 14 shows the average color rendering evaluation number Ra for each case where output light is realized using the red light source 42r according to the modified example, the green light source 42g according to the modified example, and the white light source 42w (RGWW in FIG. 14) and the case where output light is realized using the white light source 42w, the green light source 42g according to the modified example, and the blue light source 42b according to the modified example (WWGB in FIG. 14) by Control Example 1 when the color temperature of the white light source 42w is 3500K (warm white: WW). In FIG. 14, the average color rendering evaluation number Ra for the case where output light is realized by the red light source 42r according to the modified example, the green light source 42g according to the modified example, and the blue light source 42b according to the modified example (RGB in FIG. 14) by the comparative example is also shown together.

[0056] FIG. 15 shows the average color rendering evaluation number Ra for each case where output light is realized using the red light source 42r according to the modified example, the green light source 42g according to the modified example, and the white light source 42w (RGD in FIG. 15) and the case where output light is realized using the white light source 42w, the green light source 42g according to the modified example, and the blue light source 42b according to the modified example (DGB in FIG. 15) by Control Example 1 when the color temperature of the white light source 42w is 6500K (daylight white: D). In FIG. 15, the average color rendering evaluation number Ra for the case where output light is realized by the red light source 42r according to the modified example, the green light source 42g according to the modified example, and the blue light source 42b according to the modified example (RGB in FIG. 15) by the comparative example is also shown together.

[0057] As shown in FIGS. 13 to 15, even when Control Example 1 is applied to the three-color light source according to the modified example, output light having an average color rendering evaluation number Ra higher than that of the comparative example can be realized.

[0058] [Effects, etc.] As described above, the lighting system 10 includes a control unit 31 that controls a first light source that emits light having a first chromaticity value, a second light source that emits light having a second chromaticity value, a third light source that emits light having a third chromaticity value, and a fourth light source that emits light having a fourth chromaticity value. On the chromaticity coordinates, the triangular region with the points indicating the first chromaticity value, the point indicating the second chromaticity value, and the point indicating the third chromaticity value as vertices encloses the chromaticity range of the light source color defined in JIS Z9112, and on the chromaticity coordinates, the point indicating the fourth chromaticity value is located within the chromaticity range. The control unit 31 realizes output light having a chromaticity value within the triangular region a having, as vertices, two of the points indicating the first chromaticity value, the point indicating the second chromaticity value, and the point indicating the third chromaticity value, and the point indicating the fourth chromaticity value, by causing two light sources corresponding to the two points and the fourth light source among the first light source, the second light source, and the third light source to emit light. In the above embodiment, the first light source is the blue light source 42b, the second light source is the green light source 42g, the third light source is the red light source 42r, and the fourth light source is the white light source 42w. The region a is, for example, any one of the regions 1a, 2a, and 3a of the above embodiment.

[0059] Such a lighting system 10 can realize output light having a high average color rendering evaluation number Ra.

[0060] Further, for example, the control unit 31 realizes output light having a chromaticity value within the region b by causing the first light source, the second light source, the third light source, and the fourth light source to emit light, where the first boundary point is located on the line segment connecting one of the two points and the point indicating the fourth chromaticity value, the second boundary point is located on the line segment connecting the other of the two points and the point indicating the fourth chromaticity value, and the chromaticity value within the triangular region b having the point indicating the fourth chromaticity value as the vertex. The region b is, for example, any one of the region 1b, the region 2b, and the region 3b in the above embodiment.

[0061] Such an illumination system 10 can increase the maximum light amount of the output light having a chromaticity value within the region b.

[0062] Further, for example, the first boundary point is a point indicating the chromaticity value when the light source corresponding to one of the two points and the fourth light source emit light at the maximum brightness, and the second boundary point is a point indicating the chromaticity value when the light source corresponding to the other of the two points and the fourth light source emit light at the maximum brightness. The first boundary point is, for example, one of the boundary point B1, the boundary point G1, and the boundary point B1 in the above embodiment, and the second boundary point is, for example, another one of the boundary point B1, the boundary point G1, and the boundary point B1 in the above embodiment.

[0063] Such an illumination system 10 can increase the maximum light amount of the output light having a chromaticity value within the region b.

[0064] Further, for example, the control unit 31 selectively executes the control of the first mode that realizes the output light having a chromaticity value within the region b by causing two light sources and the fourth light source to emit light, and the control of the second mode that realizes the output light having a chromaticity value within the region b by causing the first light source, the second light source, the third light source, and the fourth light source to emit light. The first mode is, for example, the color rendering property - emphasized mode in the above embodiment, and the second mode is, for example, the light amount - emphasized mode in the above embodiment.

[0065] Such an illumination system 10 can switch the method of realizing the chromaticity value within the region b (chromaticity control method).

[0066] Also, a lighting method executed by a computer such as the lighting system 10 includes a control step of controlling a first light source that emits light having a first chromaticity value, a second light source that emits light having a second chromaticity value, a third light source that emits light having a third chromaticity value, and a fourth light source that emits light having a fourth chromaticity value. On the chromaticity coordinates, the triangular region with the points indicating the first chromaticity value, the second chromaticity value, and the third chromaticity value as vertices encloses the chromaticity range of the light source color defined in JIS Z9112, and on the chromaticity coordinates, the point indicating the fourth chromaticity value is located within the chromaticity range. In the control step, output light having a chromaticity value within the triangular region a with two of the points indicating the first chromaticity value, the second chromaticity value, and the third chromaticity value and the point indicating the fourth chromaticity value as vertices is realized by causing two light sources corresponding to two of the points among the first light source, the second light source, and the third light source and the fourth light source to emit light.

[0067] Such a lighting method can realize output light having a high average color rendering index Ra.

[0068] (Other Embodiments) Although the embodiments have been described above, the present invention is not limited to the above embodiments.

[0069] For example, it is not essential that a blue light source, a green light source, and a red light source be used as the first light source, the second light source, and the third light source. As the first light source, the second light source, and the third light source, three light sources having chromaticity values that form a triangle enclosing the chromaticity range of the light source color on the chromaticity coordinates may be used.

[0070] Also, in the above embodiment, the light emitted by the three-color light sources is realized by the emitted light of the LED or the fluorescence emitted by the phosphor, but it may also be realized by the emitted light of a semiconductor laser (laser light), the emitted light of an organic EL element (Electro-Luminescence), or the emitted light of an inorganic EL element.

[0071] For example, in the above embodiment, the lighting system is implemented by a plurality of devices, but it may also be implemented as a single device. For example, the lighting system may be implemented as a single device corresponding to the control device according to the above embodiment. When the lighting system is implemented by a plurality of devices, the components included in the lighting system described in the above embodiment may be distributed among the plurality of devices in any manner.

[0072] Also, in the above embodiment, the processing executed by a specific processing unit may be executed by another processing unit. Also, the order of a plurality of processes may be changed, or a plurality of processes may be executed in parallel.

[0073] Also, in the above embodiment, each component may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.

[0074] Also, each component may be realized by hardware. Each component may be a circuit (or an integrated circuit). These circuits may form one circuit as a whole, or may be separate circuits respectively. Also, each of these circuits may be a general-purpose circuit or a dedicated circuit.

[0075] Also, the general or specific aspects of the present invention may be realized by a system, a device, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM. Also, it may be realized by any combination of a system, a device, a method, an integrated circuit, a computer program, and a recording medium.

[0076] For example, the present invention may be realized as an illumination method executed by a computer such as an illumination system, or may be realized as a program for causing a computer to execute the illumination method, or may be realized as a computer-readable non-transitory recording medium on which such a program is recorded.

[0077] In addition, forms obtained by applying various modifications conceivable by those skilled in the art to each embodiment, or forms realized by arbitrarily combining the components and functions in each embodiment without departing from the gist of the present invention are also included in the present invention.

Explanation of Reference Numerals

[0078] Regions 1a, 1b, 2a, 2b, 3a, 3b 10 Illumination system 20 Input device 30 Control device 31 Control unit 32 Storage unit 40 Illumination device 41 Dimming circuit 42 Light source unit 42b Blue light source 42g Green light source 42r Red light source 42w White light source

Claims

Claim 1 A control unit that controls a first light source that emits light having a first chromaticity value, a second light source that emits light having a second chromaticity value, a third light source that emits light having a third chromaticity value, and a fourth light source that emits light having a fourth chromaticity value, On the chromaticity coordinates, the triangular region with the points indicating the first chromaticity value, the point indicating the second chromaticity value, and the point indicating the third chromaticity value as vertices encloses the chromaticity range of the light source color defined in JIS Z9112, On the chromaticity coordinates, the point indicating the fourth chromaticity value is located within the chromaticity range, The control unit realizes output light having a chromaticity value within a triangular region a having as vertices two of the points indicating the first chromaticity value, the point indicating the second chromaticity value, and the point indicating the third chromaticity value, and the point indicating the fourth chromaticity value, by causing only two light sources corresponding to the two points among the first light source, the second light source, and the third light source, and the fourth light source to emit light, The fourth light source emits white light having a color temperature higher than that of the bulb color defined in JIS Z9112 Illumination system. Claim 2 The control unit realizes output light having a chromaticity value within a triangular region b having as vertices a first boundary point located on the line segment connecting one of the two points and the point indicating the fourth chromaticity value, a second boundary point on the line segment connecting the other of the two points and the point indicating the fourth chromaticity value, and the point indicating the fourth chromaticity value, by causing the first light source, the second light source, the third light source, and the fourth light source to emit light The illumination system according to claim 1. Claim 3 The first boundary point is a point indicating the chromaticity value when each of the light source corresponding to one of the two points and the fourth light source emits light at maximum brightness, The second boundary point is a point indicating the chromaticity value when each of the light source corresponding to the other of the two points and the fourth light source emits light at maximum brightness The illumination system according to claim 2. Claim 4 The control unit selectively executes control in a first mode in which output light having a chromaticity value within the region b is realized by causing only the two light sources and the fourth light source to emit light, and control in a second mode in which output light having a chromaticity value within the region b is realized by causing the first light source, the second light source, the third light source, and the fourth light source to emit light The illumination system according to claim 2 or 3. Claim 5 A control unit that controls a first light source that emits blue light having a first chromaticity value, a second light source that emits light having a second chromaticity value, a third light source that emits light having a third chromaticity value, and a fourth light source that emits light having a fourth chromaticity value is provided. On the chromaticity coordinates, the triangular region with the points indicating the first chromaticity value, the points indicating the second chromaticity value, and the points indicating the third chromaticity value as vertices encloses the chromaticity range of the light source color defined in JIS Z9112. On the chromaticity coordinates, the point indicating the fourth chromaticity value is located within the chromaticity range. The control unit realizes output light having a chromaticity value within a triangular region a with the point indicating the first chromaticity value, one of the points indicating the second chromaticity value and the points indicating the third chromaticity value, and the point indicating the fourth chromaticity value as vertices, by causing only the first light source, the light source corresponding to the one point among the second light source and the third light source, and the fourth light source to emit light. An illumination system.

6. Including a control step of controlling a first light source that emits light having a first chromaticity value, a second light source that emits light having a second chromaticity value, a third light source that emits light having a third chromaticity value, and a fourth light source that emits light having a fourth chromaticity value. On the chromaticity coordinates, the triangular region with the points indicating the first chromaticity value, the points indicating the second chromaticity value, and the points indicating the third chromaticity value as vertices encloses the chromaticity range of the light source color defined in JIS Z9112. On the chromaticity coordinates, the point indicating the fourth chromaticity value is located within the chromaticity range. In the control step, output light having a chromaticity value within a triangular region a with two of the points indicating the first chromaticity value, the points indicating the second chromaticity value, and the points indicating the third chromaticity value, and the point indicating the fourth chromaticity value as vertices is realized by causing only the first light source, the two light sources corresponding to the two points among the second light source and the third light source, and the fourth light source to emit light. The fourth light source emits white light having a color temperature higher than that of the bulb color defined in JIS Z9112. An illumination method.

7. Including a control step of controlling a first light source that emits blue light having a first chromaticity value, a second light source that emits light having a second chromaticity value, a third light source that emits light having a third chromaticity value, and a fourth light source that emits light having a fourth chromaticity value. On the chromaticity coordinates, the triangular region with vertices at the point indicating the first chromaticity value, the point indicating the second chromaticity value, and the point indicating the third chromaticity value encloses the chromaticity range of the light source color defined in JIS Z9112, on the chromaticity coordinates, the point indicating the fourth chromaticity value is located within the chromaticity range, in the control step, the output light having a chromaticity value within the triangular region a with vertices at the point indicating the first chromaticity value, one of the points among the point indicating the second chromaticity value and the point indicating the third chromaticity value, and the point indicating the fourth chromaticity value is realized by causing only the first light source, the light source corresponding to the one point among the second light source and the third light source, and the fourth light source to emit light lighting method. [

8. ] A program for causing a computer to execute the lighting method according to claim 6 or 7.

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