Lighting device

Abstract

To provide a lighting device capable of reducing color shift from a black body locus of illumination light.SOLUTION: A lighting device includes: a first light emitting unit having a plurality of first light emitting elements; a second light emitting unit having a plurality of second light emitting elements and whose color temperature is different from that of the first light emitting unit; and a control circuit that controls an output of each of the first light emitting unit and the second light emitting unit. The plurality of first light emitting elements are classified into an upper first light emitting element group in which a y value on an xy chromaticity diagram is higher than a black body locus and a lower first light emitting element group in which the y value on the xy chromaticity diagram is lower than the black body locus. The control circuit controls a light output ratio between the upper first light emitting element group and the lower first light emitting element group.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present disclosure relates to a lighting device, and more particularly to a lighting device with adjustable light color. [Background technology]

[0002] Conventionally, lighting devices have been known that have a color adjustment function that changes the color of illumination light depending on the purpose of use, the usage situation, etc. For example, Patent Document 1 discloses that in a lighting device that includes a light-emitting unit consisting of two LED lamp groups with different color temperatures and a control circuit that controls the dimming of the light-emitting unit, the color of illumination light is adjusted by controlling the input voltage to the two light-emitting units with the control circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-110781 Summary of the Invention [Problem to be solved by the invention]

[0004] When adjusting the color of illumination light using two light-emitting units with different light colors, the color is adjusted on a line connecting two chromaticity coordinates on a chromaticity diagram. For example, as in Patent Document 1, when the emission colors of the two light-emitting units are daylight and incandescent, the color of the illumination light is changed according to the chromaticity on a line connecting the chromaticity coordinates of the daylight-color light-emitting unit and the incandescent-color light-emitting unit on the chromaticity diagram. In this case, a color shift occurs between the illumination light and the blackbody locus, reducing the comfort or naturalness of the illumination light.

[0005] The present disclosure is intended to solve the above-mentioned problems, and has an object to provide an illumination device that can reduce color deviation from the blackbody locus of illumination light. [Means for solving the problem]

[0006] The lighting device according to the present disclosure comprises a first light-emitting section having a plurality of first light-emitting elements, a second light-emitting section having a plurality of second light-emitting elements and having a different color temperature from the first light-emitting section, and a control circuit that controls the output of each of the first light-emitting section and the second light-emitting section, wherein the plurality of first light-emitting elements are classified into an upper group of first light-emitting elements whose y-values ​​on the xy chromaticity diagram are higher than the blackbody locus, and a lower group of first light-emitting elements whose y-values ​​on the xy chromaticity diagram are lower than the blackbody locus, and the control circuit controls the light output ratio between the upper group of first light-emitting elements and the lower group of first light-emitting elements. [Effects of the Invention]

[0007] According to the lighting device of the present disclosure, the color deviation of the illumination light from the blackbody locus can be reduced by controlling the light output ratio between the upper first light-emitting element group and the lower first light-emitting element group, which are classified above and below the blackbody locus. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an exploded perspective view of a lighting device according to a first embodiment. [Figure 2] FIG. 2 is a side view of the device body according to the first embodiment. [Figure 3] FIG. 2 is an exploded perspective view of the device body according to the first embodiment. [Figure 4] 1 is a schematic configuration diagram of a power supply unit and a light source module of an illumination device according to a first embodiment. [Figure 5] 5 is a diagram illustrating variations in color temperature of the first light-emitting element and the second light-emitting element according to the first embodiment. FIG. [Figure 6] 3 is a diagram showing an example of an arrangement of light emitting elements in the light source module according to the first embodiment. FIG. [Figure 7] 4 is a flowchart showing the flow of a color matching process according to the first embodiment. [Figure 8] 10 is a flowchart showing the flow of a process for obtaining a luminous flux and standard chromaticity coordinates according to the first embodiment. [Figure 9] 3 is a diagram illustrating standard chromaticity coordinates of the lighting device according to the first embodiment. FIG. [Figure 10]FIG. 2 is a diagram illustrating a method for calculating a plurality of intersections between the blackbody locus and a line connecting chromaticity coordinates on a first line L1 and chromaticity coordinates on a second line L2 in the first embodiment. [Figure 11] FIG. 2 is a diagram illustrating a method for calculating a plurality of intersections between the blackbody locus and a line connecting chromaticity coordinates on a first line L1 and chromaticity coordinates on a second line L2 in the first embodiment. [Figure 12] 10 is a schematic configuration diagram of a power supply unit and a light source module of an illumination device according to a second embodiment. FIG. [Figure 13] 10 is a diagram showing an example of an arrangement of light emitting elements in a light source module according to the second embodiment. FIG. [Figure 14] 10 is a flowchart showing the flow of a color matching process according to the second embodiment. [Figure 15] 10 is a flowchart showing the flow of a process for obtaining a luminous flux and standard chromaticity coordinates in the second embodiment. [Figure 16] FIG. 10 is a diagram illustrating standard chromaticity coordinates of the lighting device according to the second embodiment. [Figure 17] FIG. 10 is a diagram illustrating a method for calculating a plurality of intersections between a line connecting chromaticity coordinates on a first line and a second chromaticity coordinate and the blackbody locus in the second embodiment. [Figure 18] FIG. 10 is a diagram illustrating a method for calculating a plurality of intersections between a line connecting chromaticity coordinates on a first line and a second chromaticity coordinate and the blackbody locus in a modification of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of a lighting device 100 according to the present disclosure will be described below with reference to the drawings. In each drawing, the same reference numerals denote the same or equivalent parts, and this is common throughout the specification. Note that in each drawing, the relative dimensional relationships or shapes of each component may differ from those in reality.

[0010] Embodiment 1 1 is an exploded perspective view of a lighting device 100 according to embodiment 1. The lighting device 100 includes a fixture body 1, a mounting frame 21, a mounting spring 22, a power supply unit 3, a power supply mounting spring 23, a terminal block 4, a power supply cover 24, and a power supply cable 25. The power supply unit 3 is held in the fixture body 1 by the power supply mounting spring 23. A commercial power line and a control signal line are connected to the terminal block 4 from outside.

[0011] The power supply unit 3 converts commercial power supplied from an external source into DC power via the terminal block 4. The power supply unit 3 supplies the DC power to the light source module 5 of the fixture body 1 via the power supply cable 25, thereby lighting up the light source module 5.

[0012] Fig. 2 is a side view of the fixture body 1 according to the first embodiment. Fig. 3 is an exploded perspective view of the fixture body 1 according to the first embodiment. As shown in Figs. 2 and 3, the fixture body 1 includes a main body frame 11, a lens 12, a light source module 5, and a heat dissipation unit 13. The light source module 5 is fixed to the heat dissipation unit 13 by screws, an adhesive, or the like (not shown). Light emitted from the light source module 5 passes through the lens 12 and is distributed.

[0013] 4 is a schematic configuration diagram of the power supply unit 3 and light source module 5 of the lighting device 100 according to embodiment 1. The power supply unit 3 includes an AC / DC converter 31, a lighting circuit 32, and a control circuit 33. The lighting circuit 32 includes a first lighting circuit 321 and a second lighting circuit 322. Note that the configuration of the power supply unit 3 is not limited to the example shown in FIG. 4, and may further include a noise suppression circuit including an L-type or Π-type noise filter, a DC / DC converter, or the like.

[0014] The AC / DC converter 31 converts the AC voltage of the commercial power supply into a DC voltage and supplies it to the lighting circuit 32. The lighting circuit 32 operates on the DC voltage converted by the AC / DC converter 31 and supplies power to the light source module 5. The first lighting circuit 321 supplies power to the first light-emitting unit 6 of the light source module 5, and the second lighting circuit 322 supplies power to the second light-emitting unit 7 of the light source module 5.

[0015] The control circuit 33 includes a control unit 331 and a storage unit 332. The control unit 331 is configured with hardware such as a dedicated single circuit or composite circuit, a microcomputer that executes a program, or a combination of these. The control unit 331 controls the output current of the first lighting circuit 321 and the second lighting circuit 322, the optical output ratio of each light-emitting element of the light source module 5, etc. in response to an instruction signal from the user, including an instruction to turn the lighting device 100 on / off and an instruction to the brightness or color of the illumination light.

[0016] The storage unit 332 is a non-volatile memory such as a ROM or an EEPROM, and stores programs used to control the control unit 331, as well as various data such as calculation formulas, threshold values, a temperature correction table (described later), and a color adjustment table used to execute the programs.

[0017] The light source module 5 includes a first light-emitting unit 6, a second light-emitting unit 7, and a temperature sensor 8. The first light-emitting unit 6 and the second light-emitting unit 7 emit light of different color temperatures. For example, the first light-emitting unit 6 emits white light with a color temperature of 5000 [K], and the second light-emitting unit 7 emits white light with a color temperature of 3000 [K]. The color temperatures of the first light-emitting unit 6 and the second light-emitting unit 7 are not limited to those described above. For example, the color temperature of the first light-emitting unit 6 may be 6500 [K], and the color temperature of the second light-emitting unit 7 may be 2700 [K].

[0018] The first light-emitting unit 6 includes a plurality of first light-emitting elements 60. The second light-emitting unit 7 includes a plurality of second light-emitting elements 70. The first light-emitting elements 60 and the second light-emitting elements 70 are bullet-type, surface-mounted (SMD) type, or chip-on-board (COB) type LEDs (Light Emitting Diodes). Alternatively, the first light-emitting elements 60 and the second light-emitting elements 70 may be laser light sources or organic EL light sources.

[0019] Although the color temperature of each of the light-emitting elements, such as the first light-emitting element 60 and the second light-emitting element 70, is determined as a component specification, variations in the actual color temperature occur even among light-emitting elements with the same component specification due to variations in manufacturing process. This variation usually exhibits a normal distribution, and not all light-emitting elements are positioned at the center of the color temperature determined as a component specification. Therefore, light-emitting elements purchased (produced) at different times may have different color temperatures even if they have the same component specification.

[0020] In the first light-emitting unit 6, the plurality of first light-emitting elements 60 are divided into two groups, an upper first light-emitting element group 61 and a lower first light-emitting element group 62, according to variations in color temperature. The first light-emitting elements 60 included in the upper first light-emitting element group 61 are referred to as upper first light-emitting elements 610, and the first light-emitting elements 60 included in the lower first light-emitting element group 62 are referred to as lower first light-emitting elements 620. Similarly, in the second light-emitting unit 7, the plurality of second light-emitting elements 70 are divided into two groups, an upper second light-emitting element group 71 and a lower second light-emitting element group 72, according to variations in color temperature. The second light-emitting elements 70 included in the upper second light-emitting element group 71 are referred to as upper second light-emitting elements 710, and the second light-emitting elements 70 included in the lower second light-emitting element group 72 are referred to as lower second light-emitting elements 720. Note that, although each light-emitting element group includes multiple light-emitting elements in FIG. 4, the number of light-emitting elements included in each light-emitting element group may be one or more.

[0021] FIG. 5 is a diagram illustrating the variation in color temperature between the first light-emitting element 60 and the second light-emitting element 70 according to the first embodiment. The dashed-dotted line in FIG. 5 indicates the iso-color temperature line of 5000 [K], which is the color temperature of the first light-emitting element 60. The dashed-two-dotted line in FIG. 5 indicates the iso-color temperature line of 3000 [K], which is the color temperature of the second light-emitting element 70. As shown in FIG. 5, the color temperature variation range R1 of the first light-emitting element 60 is a range exceeding one step of the MacAdam ellipse including the iso-color temperature line of 5000 [K], e.g., a range equivalent to five steps. The color temperature variation range R2 of the second light-emitting element 70 is a range exceeding one step of the MacAdam ellipse including the iso-color temperature line of 3000 [K], e.g., a range equivalent to five steps.

[0022] Of the multiple first light-emitting elements 60, those in an upper region R11 of the color temperature variation range R1 on the xy chromaticity diagram are classified as upper first light-emitting elements 610, and those in a lower region R12 are classified as lower first light-emitting elements 620. Similarly, of the multiple second light-emitting elements 70, those in an upper region R21 of the color temperature variation range R2 on the xy chromaticity diagram are classified as upper second light-emitting elements 710, and those in a lower region R22 are classified as lower second light-emitting elements 720.

[0023] The light-emitting elements are classified so that at least the chromaticity coordinates of the upper first light-emitting element group 61 and the upper second light-emitting element group 71 are above the blackbody locus, and the chromaticity coordinates of the lower first light-emitting element group 62 and the lower second light-emitting element group 72 are below the blackbody locus. In other words, the light-emitting elements are classified so that the y values ​​in the xy chromaticity diagram of the upper first light-emitting element group 61 and the upper second light-emitting element group 71 are higher than the blackbody locus, and the y values ​​in the xy chromaticity diagram of the lower first light-emitting element group 62 and the lower second light-emitting element group 72 are lower than the blackbody locus.

[0024] FIG. 6 is a diagram illustrating an example of the arrangement of light-emitting elements in the light source module 5 according to the first embodiment. As illustrated in FIG. 6, the light-emitting elements of the light source module 5 are arranged in a light source array that is close to a square, for example. Specifically, on the substrate 51 of the light source module 5, a first column C1 in which the upper first light-emitting element 610, the lower second light-emitting element 720, the lower first light-emitting element 620, and the upper second light-emitting element 710 are arranged one by one from left to right is alternately arranged, and a second column C2 in which the lower second light-emitting element 720, the upper first light-emitting element 610, the upper second light-emitting element 710, and the lower first light-emitting element 620 are arranged one by one from left to right is alternately arranged. In this manner, by arranging the upper first light-emitting element 610 and the lower first light-emitting element 620, and the upper second light-emitting element 710 and the lower second light-emitting element 720 diagonally so as not to be adjacent to each other, the visual chromaticity difference can be made less noticeable. In FIG. 6, two sets of first columns C1 and second columns C2 are arranged on the substrate 51, but the number of sets is not limited to two and may be one or more.

[0025] Returning to FIG. 4 , the first light-emitting unit 6 includes an upper switch element 63 connected in parallel with the upper first light-emitting element group 61, and a lower switch element 64 connected in parallel with the lower first light-emitting element group 62. The upper switch element 63 and the lower switch element 64 are, for example, MOSFETs. The control circuit 33 drives the upper switch element 63 and the lower switch element 64 to control the currents supplied to the upper first light-emitting element group 61 and the lower first light-emitting element group 62, respectively. The drive signals for the upper switch element 63 and the lower switch element 64 are, for example, PWM (Pulse Width Modulation) signals. The upper switch element 63 and the lower switch element 64 control the optical output ratio between the upper first light-emitting element group 61 and the lower first light-emitting element group 62. The optical output ratio between the upper first light-emitting element group 61 and the lower first light-emitting element group 62 corresponds to the ratio between the value of the current flowing through the upper first light-emitting element group 61 and the value of the current flowing through the lower first light-emitting element group 62.

[0026] The second light-emitting unit 7 includes an upper switch element 73 connected in parallel with the upper second light-emitting element group 71 and a lower switch element 74 connected in parallel with the lower second light-emitting element group 72. The upper switch element 73 and the lower switch element 74 are, for example, MOSFETs. The control circuit 33 drives the upper switch element 73 and the lower switch element 74 to control the current supplied to the upper second light-emitting element group 71 and the lower second light-emitting element group 72. The drive signals for the upper switch element 73 and the lower switch element 74 are, for example, PWM signals. The upper switch element 73 and the lower switch element 74 control the optical output ratio between the upper second light-emitting element group 71 and the lower second light-emitting element group 72. The optical output ratio between the upper second light-emitting element group 71 and the lower second light-emitting element group 72 corresponds to the ratio between the value of the current flowing through the upper second light-emitting element group 71 and the value of the current flowing through the lower second light-emitting element group 72.

[0027] The temperature sensor 8 is, for example, a thermistor, and measures the temperature of the light source module 5. As shown in FIG. 6, the temperature sensor 8 is disposed on the substrate 51 of the light source module 5 near the first light-emitting unit 6 and the second light-emitting unit 7. The temperature measured by the temperature sensor 8 is transmitted to the control circuit 33. The number of temperature sensors 8 is not limited to one, and multiple temperature sensors 8 may be provided. In this case, for example, the average value of the temperatures measured by the multiple temperature sensors 8 is used as the measurement result.

[0028] Next, a color adjustment process in the lighting device 100 of this embodiment will be described. In the light source module 5 of this embodiment, the light output ratio between the upper first light-emitting element group 61 and the lower first light-emitting element group 62 is controlled, thereby realizing a light color within a range of 5000 [K] in the first light-emitting unit 6. Similarly, the light output ratio between the upper second light-emitting element group 71 and the lower second light-emitting element group 72 is controlled, thereby realizing a light color within a range of 3000 [K] in the second light-emitting unit 7. Then, by controlling the light output ratio between the upper first light-emitting element group 61 and the lower first light-emitting element group 62 and the light output ratio between the upper second light-emitting element group 71 and the lower second light-emitting element group 72, respectively, a light color within a range of 3000 [K] to 5000 [K] is realized in the light source module 5 as a whole.

[0029] 7 is a flowchart showing the flow of the color adjustment process in embodiment 1. First, the luminous flux and standard chromaticity coordinates of each light-emitting element group in the light source module 5 are acquired (S1). The process of step S1 is performed during the manufacture of the lighting device 100 in order to understand the characteristics of the light-emitting elements mounted in the lighting device 100. Specifically, the process of step S1 is performed by a calculation computer and each measurement device when the light source module 5 or the lighting device 100 is completed.

[0030] FIG. 8 is a flowchart showing the flow of a process for acquiring luminous flux and standard chromaticity coordinates in the first embodiment. First, the temperature of the turned-on light source module 5 is measured (S11). The measured temperature is stored in the memory unit 332 of the control circuit 33 as the standard temperature T0. Then, the upper first light-emitting element group 61 of the first light-emitting unit 6 is turned on, and the luminous flux of the upper first light-emitting element group 61 is measured (S12). Here, only the upper first light-emitting element group 61 is turned on, and the lower first light-emitting element group 62 and the second light-emitting unit 7 are not turned on. Then, the color temperature of the upper first light-emitting element group 61 is measured, and the chromaticity coordinates are identified (S13). The identified chromaticity coordinates are stored in the memory unit 332 of the control circuit 33 together with the luminous flux measured as the standard chromaticity coordinates (xs11, ys11) of the upper first light-emitting element group 61.

[0031] Next, the lower first light-emitting element group 62 of the first light-emitting unit 6 is turned on, and the luminous flux of the lower first light-emitting element group 62 is measured (S14). Here, only the lower first light-emitting element group 62 is turned on, and the upper first light-emitting element group 61 and the second light-emitting unit 7 are not turned on. Then, the color temperature of the lower first light-emitting element group 62 is measured, and the chromaticity coordinates are identified (S15). The identified chromaticity coordinates are stored in the memory unit 332 of the control circuit 33 together with the luminous flux measured as the standard chromaticity coordinates (xs12, ys12) of the lower first light-emitting element group 62.

[0032] Next, the upper second light-emitting element group 71 of the second light-emitting unit 7 is turned on, and the luminous flux of the upper second light-emitting element group 71 is measured (S16). Here, only the upper second light-emitting element group 71 is turned on, and the lower second light-emitting element group 72 and the first light-emitting unit 6 are not turned on. Then, the color temperature of the upper second light-emitting element group 71 is measured, and the chromaticity coordinates are identified (S17). The identified chromaticity coordinates are stored in the memory unit 332 of the control circuit 33 together with the luminous flux measured as the standard chromaticity coordinates (xs21, ys21) of the upper second light-emitting element group 71.

[0033] Next, the lower second light-emitting element group 72 of the second light-emitting unit 7 is turned on, and the luminous flux of the lower second light-emitting element group 72 is measured (S18). Here, only the lower second light-emitting element group 72 is turned on, and the upper second light-emitting element group 71 and the first light-emitting unit 6 are not turned on. Then, the color temperature of the lower second light-emitting element group 72 is measured, and the chromaticity coordinates are identified (S19). The identified chromaticity coordinates are stored in the memory unit 332 of the control circuit 33 together with the luminous flux measured as the standard chromaticity coordinates (xs22, ys22) of the lower second light-emitting element group 72.

[0034] 9 is a diagram illustrating the standard chromaticity coordinates of the lighting device 100 according to Embodiment 1. As shown in FIG. 9, the y value of the line connecting the standard chromaticity coordinates (xs11, ys11) of the upper first light-emitting element group 61 and the standard chromaticity coordinates (xs21, ys21) of the upper second light-emitting element group 71 on the xy chromaticity diagram is higher than the y value of the blackbody locus. Furthermore, the y value of the line connecting the standard chromaticity coordinates (xs12, ys12) of the lower first light-emitting element group 62 and the standard chromaticity coordinates (xs22, ys22) of the lower second light-emitting element group 72 on the xy chromaticity diagram is lower than the y value of the blackbody locus. As a result, the light source module 5 can realize light colors within the quadrangular region Rs connecting the four chromaticity coordinates (xs11, ys11), (xs12, ys12), (xs21, ys21), and (xs22, ys22), which includes the blackbody locus.

[0035] Returning to FIG. 7, the processing performed when the lighting device 100 is in use (when turned on) will be described. The processing performed when the lighting device 100 is in use is performed by the control unit 331 of the control circuit 33. First, the control unit 331 acquires the temperature of the light source module 5 measured by the temperature sensor 8 (S2). Then, the control unit 331 corrects the standard chromaticity coordinates and luminous flux of each light-emitting element group based on the temperature difference between the standard temperature T0 stored in the storage unit 332 and the measured temperature T measured by the temperature sensor 8 (S3). The control unit 331 corrects the standard chromaticity coordinates using a temperature correction table or a calculation formula stored in advance in the storage unit 332, and obtains the luminous flux and chromaticity coordinates corresponding to the measured temperature T. This allows the upper first chromaticity coordinate (x11, y11) corresponding to the measured temperature T of the upper first light-emitting element group 61, the lower first chromaticity coordinate (x12, y12) corresponding to the measured temperature T of the lower first light-emitting element group 62, the upper second chromaticity coordinate (x21, y21) corresponding to the measured temperature T of the upper second light-emitting element group 71, and the lower second chromaticity coordinate (x22, y22) corresponding to the measured temperature T of the lower second light-emitting element group 72 to be determined.

[0036] Next, the control unit 331 calculates a first line L1 connecting the upper first chromaticity coordinate (x11, y11) and the lower first chromaticity coordinate (x12, y12) on the xy chromaticity diagram (S4). The control unit 331 also calculates a second line L2 connecting the upper second chromaticity coordinate (x21, y21) and the lower second chromaticity coordinate (x22, y22) (S5).

[0037] Then, the control unit 331 calculates multiple intersections between the blackbody locus and a line connecting the chromaticity coordinates on the first line L1 and the chromaticity coordinates on the second line L2 on the xy chromaticity diagram (S6). Figures 10 and 11 are diagrams illustrating a method for calculating multiple intersections between the blackbody locus and a line connecting the chromaticity coordinates on the first line L1 and the chromaticity coordinates on the second line L2 in the first embodiment. Specifically, in Figures 10 and 11, the line connecting the chromaticity coordinates on the first line L1 and the chromaticity coordinates on the second line L2 is moved like a seesaw around the chromaticity coordinates on the diagonal first line L1 and the chromaticity coordinates on the second line L2 as fulcrums to determine the intersections with the blackbody locus.

[0038] First, as shown in FIG. 10, a line L12 connecting the upper first chromaticity coordinate (x11, y11) and the lower second chromaticity coordinate (x22, y22) is calculated. One end of the line L12 is fixed at the upper first chromaticity coordinate (x11, y11), and the other end of the line L12 is moved from the lower second chromaticity coordinate (x22, y22) to the upper second chromaticity coordinate (x21, y21) along the second line L2. The control unit 331 stores, in the memory unit 332, the chromaticity coordinates of multiple intersections between the line L12 and the blackbody locus during this movement, as well as the chromaticity coordinates on the second line L2 corresponding to each intersection. The chromaticity coordinates of the multiple intersections are chromaticity coordinates along the blackbody locus, and the chromaticity coordinates on the second line L2 are the chromaticity coordinates of the second light-emitting unit 7. In other words, in FIG. 10, the intersections of the blackbody locus with a plurality of straight lines connecting the upper first chromaticity coordinate (x11, y11) and each chromaticity coordinate on the second line L2 are determined.

[0039] Next, as shown in FIG. 11, a line L21 connecting the lower second chromaticity coordinates (x22, y22) and the upper first chromaticity coordinates (x11, y11) is calculated. One end of the line L21 is fixed at the lower second chromaticity coordinates (x22, y22), and the other end of the line L21 is moved from the upper first chromaticity coordinates (x11, y11) along the first line L1 to the lower first chromaticity coordinates (x12, y12). The chromaticity coordinates of multiple intersections between the line L21 and the blackbody locus during this movement, as well as the chromaticity coordinates on the first line L1 corresponding to each intersection, are stored in the storage unit 332. The chromaticity coordinates of the multiple intersections are chromaticity coordinates along the blackbody locus, and the chromaticity coordinates on the first line L1 are the chromaticity coordinates of the first light-emitting unit 6. In other words, in FIG. 11, the intersections of the blackbody locus with a plurality of straight lines connecting the lower second chromaticity coordinate (x22, y22) and each chromaticity coordinate on the first straight line L1 are determined.

[0040] 10 and 11. For example, a line connecting the upper second chromaticity coordinates (x21, y21) and the lower first chromaticity coordinates (x12, y12) may be calculated, one end of the line may be fixed to the upper second chromaticity coordinates (x21, y21) or the lower first chromaticity coordinates (x12, y12), and the other end of the line may be moved along the first line L1 or the second line L2 to calculate multiple intersections with the blackbody locus. Alternatively, multiple intersections between the blackbody locus, the chromaticity coordinates on the first line L1, and the chromaticity coordinates on the second line L2 may be calculated using a formula or a machine-learned model.

[0041] 7, the control unit 331 associates the chromaticity coordinates of the multiple intersections stored in the storage unit 332 with the chromaticity coordinates of the first light-emitting unit 6 and the chromaticity coordinates of the second light-emitting unit 7 corresponding to each intersection, and stores the associated chromaticity coordinates in the storage unit 332 as a color-matching table (S7). The color-matching table is a table in which multiple chromaticity coordinates along the blackbody locus are stored in association with the chromaticity coordinates of the first light-emitting unit 6 and the chromaticity coordinates of the second light-emitting unit 7 corresponding to each chromaticity coordinate.

[0042] The control unit 331 then controls the light output ratio of each light-emitting element group of the first light-emitting unit 6 and the second light-emitting unit 7 based on the color adjustment table (S8). Specifically, the control unit 331 extracts, from the color adjustment table, the chromaticity coordinates of the first light-emitting unit 6 and the chromaticity coordinates of the second light-emitting unit 7 that are associated with the chromaticity coordinates of the blackbody locus that correspond to the chromaticity of the desired illumination light. The control unit 331 then controls the light output ratio between the upper first light-emitting element group 61 and the lower first light-emitting element group 62, and the light output ratio between the upper second light-emitting element group 71 and the lower second light-emitting element group 72, respectively, to achieve the light color of the extracted chromaticity coordinates. This allows the illumination light of the lighting device 100 to have a light color close to the blackbody locus.

[0043] If the target chromaticity is not on the chromaticity coordinates of the blackbody locus stored in the color adjustment table, the control unit 331 may perform linear interpolation or the like to determine the chromaticity coordinates of the first light-emitting unit 6 and the second light-emitting unit 7, or the light output ratio of each light-emitting element group. The color adjustment table may also store a plurality of chromaticity coordinates along the blackbody locus, the corresponding light output ratio between the upper first light-emitting element group 61 and the lower first light-emitting element group 62 of the first light-emitting unit 6, and the corresponding light output ratio between the upper second light-emitting element group 71 and the lower second light-emitting element group 72 of the second light-emitting unit 7. Furthermore, instead of using the color adjustment table, a formula indicating the relationship between a plurality of chromaticity coordinates along the blackbody locus and the chromaticity coordinates or light output ratio of each corresponding light-emitting element group may be calculated and stored in the storage unit 332, and the light output ratio of each light-emitting element group may be controlled based on the formula.

[0044] As described above, the lighting device 100 of this embodiment includes two light-emitting units with different color temperatures. By classifying the light-emitting elements of each light-emitting unit above or below the blackbody locus based on the color temperature variation, multiple intersections with the blackbody locus can be determined on the xy chromaticity diagram. Furthermore, by controlling the light output ratio of each light-emitting element group to correspond to chromaticity coordinates along the blackbody locus, color deviation from the blackbody locus of the illumination light can be reduced. This enables color reproduction with light colors close to the blackbody locus, improving the naturalness and comfort of the illumination light. Furthermore, since there is no need to increase the number of light source colors of the light-emitting elements, increases in manufacturing costs and parts management manpower can be reduced.

[0045] Embodiment 2 An illumination device 100 according to embodiment 2 will be described. The illumination device 100 according to embodiment 2 differs from embodiment 1 in the configuration of a light source module 5A. Fig. 12 is a schematic configuration diagram of a power supply unit 3 and a light source module 5A of the illumination device 100 according to embodiment 2. The configuration of the power supply unit 3 is the same as in embodiment 1.

[0046] The light source module 5A includes a first light-emitting unit 6, a second light-emitting unit 7A, and a temperature sensor 8. The first light-emitting unit 6 and the second light-emitting unit 7A emit light of different color temperatures. For example, the first light-emitting unit 6 emits white light with a color temperature of 5000 [K], and the second light-emitting unit 7A emits white light with a color temperature of 3000 [K]. The color temperatures of the first light-emitting unit 6 and the second light-emitting unit 7A are not limited to those described above. For example, the color temperature of the first light-emitting unit 6 may be 6500 [K], and the color temperature of the second light-emitting unit 7A may be 2700 [K].

[0047] The first light-emitting unit 6 includes a plurality of first light-emitting elements 60. The second light-emitting unit 7A includes a plurality of second light-emitting elements 70. The first light-emitting elements 60 and the second light-emitting elements 70 are LEDs of a bullet type, a surface-mount type (SMD type), or a chip-on-board type (COB type). Alternatively, the first light-emitting elements 60 and the second light-emitting elements 70 may be laser light sources or organic EL light sources.

[0048] In the first light-emitting unit 6, similarly to the first embodiment, the plurality of first light-emitting elements 60 are divided into two groups, an upper first light-emitting element group 61 and a lower first light-emitting element group 62, according to variations in color temperature. The first light-emitting elements 60 included in the upper first light-emitting element group 61 are referred to as upper first light-emitting elements 610, and the first light-emitting elements 60 included in the lower first light-emitting element group 62 are referred to as lower first light-emitting elements 620. On the other hand, in the second light-emitting unit 7A of the present embodiment, the plurality of second light-emitting elements 70 are not divided according to variations in color temperature.

[0049] FIG. 13 is a diagram illustrating an example of the arrangement of light-emitting elements in a light source module 5A according to the second embodiment. As illustrated in FIG. 13, the light-emitting elements in the light source module 5A are arranged in a light source array that is, for example, close to a square. Specifically, on the substrate 51 of the light source module 5A, a first column C1 in which an upper first light-emitting element 610, a second light-emitting element 70, an upper first light-emitting element 610, and a second light-emitting element 70 are arranged in this order from left to right, and a second column C2 in which a second light-emitting element 70, a lower first light-emitting element 620, a second light-emitting element 70, and a lower first light-emitting element 620 are arranged in this order from left to right, are alternately arranged. By arranging the upper first light-emitting element 610 and the lower first light-emitting element 620 diagonally so as not to be adjacent to each other, the visual chromaticity difference can be made less noticeable. Note that, in FIG. 13, two sets of the first column C1 and the second column C2 are arranged on the substrate 51; however, the number of sets is not limited to two and may be one or more.

[0050] 12, the first light-emitting unit 6 includes an upper switch element 63 connected in parallel to the upper first light-emitting element group 61 and a lower switch element 64 connected in parallel to the lower first light-emitting element group 62, as in the first embodiment, and the optical output ratio between the upper first light-emitting element group 61 and the lower first light-emitting element group 62 is controlled by the upper switch element 63 and the lower switch element 64. On the other hand, the second light-emitting unit 7A of the present embodiment does not include a switch element, and the optical output ratio of the second light-emitting element 70 is not controlled.

[0051] Next, the color adjustment process in the lighting device 100 of this embodiment will be described. Fig. 14 is a flowchart showing the flow of the color adjustment process in embodiment 2. First, the luminous flux and standard chromaticity coordinates of each light-emitting element group in the light source module 5A are acquired (S21). The process of step S21 is performed during the manufacture of the lighting device 100 in order to understand the characteristics of the light-emitting elements mounted in the lighting device 100, as in embodiment 1. Specifically, the process of step S21 is performed by a calculation computer and each measurement device when the light source module 5A or the lighting device 100 is completed.

[0052] 15 is a flowchart showing the flow of the process of acquiring luminous flux and standard chromaticity coordinates in embodiment 2. Steps S101 to S105 of the process of acquiring luminous flux and standard chromaticity coordinates in this embodiment are the same as steps S11 to S15 of the process of acquiring luminous flux and standard chromaticity coordinates in embodiment 1. The luminous flux and standard chromaticity coordinates (xs11, ys11) of the upper first light-emitting element group 61 and the luminous flux and standard chromaticity coordinates (xs12, ys12) of the lower first light-emitting element group 62, measured and identified in steps S101 to S105, are stored in the storage unit 332 of the control circuit 33.

[0053] Next, the second light-emitting element 70 of the second light-emitting unit 7A is turned on, and the luminous flux of the second light-emitting unit 7A is measured (S106). Here, only the second light-emitting element 70 is turned on, and the first light-emitting unit 6 is not turned on. Then, the color temperature of the second light-emitting unit 7A is measured, and the chromaticity coordinates are identified (S107). The identified chromaticity coordinates are stored in the memory unit 332 of the control circuit 33 together with the luminous flux measured as the standard chromaticity coordinates (xs2, ys2) of the second light-emitting unit 7A.

[0054] Fig. 16 is a diagram illustrating the standard chromaticity coordinates of the lighting device 100 according to the second embodiment. As shown in Fig. 16, the light source module 5A according to the present embodiment can realize a light color within a triangular region Rs connecting three chromaticity coordinates (xs11, ys11), (xs12, ys12), and (xs2, ys2), which region Rs includes a portion of the blackbody locus. Note that, in order to increase the range of the blackbody locus included in the region Rs, it is desirable that the y value (ys2) of the standard chromaticity coordinates of the second light-emitting unit 7A be larger than the y value of the blackbody locus.

[0055] Returning to FIG. 14 , the processing performed when the lighting device 100 is in use (when turned on) will be described. The processing performed when the lighting device 100 is in use is performed by the control unit 331 of the control circuit 33. First, the control unit 331 measures and acquires the temperature of the turned-on light source module 5 using the temperature sensor 8 (S22). Then, the control unit 331 corrects the standard chromaticity coordinates and luminous flux of each light-emitting element group based on the temperature difference between the standard temperature T0 stored in the storage unit 332 and the measured temperature T measured by the temperature sensor 8 (S23). The control unit 331 corrects the standard chromaticity coordinates corresponding to the standard temperature T0 using a temperature correction table or a calculation formula previously stored in the storage unit 332, and obtains the luminous flux and chromaticity coordinates corresponding to the measured temperature T. This allows the upper first chromaticity coordinate (x11, y11) corresponding to the measured temperature T of the upper first light-emitting element group 61, the lower first chromaticity coordinate (x12, y12) corresponding to the measured temperature T of the lower first light-emitting element group 62, and the second chromaticity coordinate (x2, y2) corresponding to the measured temperature T of the second light-emitting section 7A to be determined.

[0056] Next, the control unit 331 calculates a first line L1 connecting the upper first chromaticity coordinate (x11, y11) and the lower first chromaticity coordinate (x12, y12) (S24).The control unit 331 then calculates multiple intersections between the blackbody locus and lines connecting the chromaticity coordinates on the first line L1 and the second chromaticity coordinates on the xy chromaticity diagram (S25).

[0057] 17 is a diagram illustrating a method for calculating multiple intersections between the blackbody locus and a line connecting the chromaticity coordinates on the first line L1 and the second chromaticity coordinates in embodiment 2. Specifically, in Fig. 17, the line connecting the chromaticity coordinates on the first line L1 and the second chromaticity coordinates (x2, y2) is moved like a seesaw with the second chromaticity coordinates (x2, y2) as the fulcrum to find the intersections with the blackbody locus.

[0058] As shown in FIG. 17, first, a line L21 connecting the second chromaticity coordinates (x2, y2) and the upper first chromaticity coordinates (x11, y11) is calculated. One end of the line L21 is fixed at the second chromaticity coordinates (x2, y2), and the other end of the line L21 is moved from the upper first chromaticity coordinates (x11, y11) along the first line L1 to the lower first chromaticity coordinates (x12, y12). The chromaticity coordinates of multiple intersections between the line L21 and the blackbody locus during this movement, as well as the chromaticity coordinates on the first line L1 corresponding to each intersection, are stored in the storage unit 332. The chromaticity coordinates of the multiple intersections are chromaticity coordinates along the blackbody locus, and the chromaticity coordinates on the first line L1 are the chromaticity coordinates of the first light-emitting unit 6. In other words, in FIG. 17, the intersections of the blackbody locus with a plurality of straight lines connecting the second chromaticity coordinate (x2, y2) and each chromaticity coordinate on the first line L1 are determined.

[0059] 14, the control unit 331 associates the chromaticity coordinates of the multiple intersections stored in the storage unit 332 with the chromaticity coordinates of the first light-emitting unit 6 corresponding to each intersection, and stores the associated chromaticity coordinates in the storage unit 332 as a color-matching table (S26). The color-matching table is a table in which multiple chromaticity coordinates along the blackbody locus are associated with the chromaticity coordinates of the first light-emitting unit 6 corresponding to each chromaticity coordinate on the blackbody locus and stored.

[0060] Then, the control unit 331 controls the light output ratio between the upper first light-emitting element group 61 and the lower first light-emitting element group 62 of the first light-emitting unit 6 based on the color adjustment table (S27). Specifically, the control unit 331 extracts, from the color adjustment table, the chromaticity coordinates of the first light-emitting unit 6 that are associated with the chromaticity coordinates of the blackbody locus that correspond to the chromaticity of the desired illumination light. Then, the control unit 331 controls the light output ratio between the upper first light-emitting element group 61 and the lower first light-emitting element group 62 so as to achieve the light color of the extracted chromaticity coordinates. This allows the illumination light of the lighting device 100 to have a light color close to the blackbody locus.

[0061] If the target chromaticity is not on the chromaticity coordinates of the blackbody locus stored in the color adjustment table, the control unit 331 may determine the chromaticity coordinates of the first light-emitting unit 6 or the light output ratio of each light-emitting element group by performing linear interpolation or the like. The color adjustment table may also store a plurality of chromaticity coordinates along the blackbody locus and the corresponding light output ratios of the upper first light-emitting element group 61 and the lower first light-emitting element group 62 of the first light-emitting unit 6. Furthermore, instead of the color adjustment table, a formula indicating the relationship between a plurality of chromaticity coordinates along the blackbody locus and the chromaticity coordinates or light output ratios of each corresponding light-emitting element group may be calculated and stored in the storage unit 332, and the light output ratio of each light-emitting element group may be controlled based on the formula.

[0062] Furthermore, in the above description, the first light-emitting elements 60 of the first light-emitting unit 6 are divided into the upper first light-emitting element group 61 and the lower first light-emitting element group 62, and the second light-emitting elements 70 of the second light-emitting unit 7 are not divided. However, the first light-emitting elements 60 of the first light-emitting unit 6 may not be divided, and the second light-emitting elements 70 of the second light-emitting unit 7 may be divided into the upper second light-emitting element group 71 and the lower second light-emitting element group 72. In this case, a line connecting the upper second chromaticity coordinates (x21, y21) of the upper second light-emitting element group 71 and the lower second chromaticity coordinates (x22, y22) of the lower second light-emitting element group 72 is defined as the second line L2, and multiple intersections of the line connecting the first chromaticity coordinates of the first light-emitting unit 6 and the chromaticity coordinates on the second line L2 with the blackbody locus are calculated and stored in the color adjustment table.

[0063] As described above, the lighting device 100 of this embodiment includes two light-emitting units with different color temperatures. By classifying the light-emitting elements of one of the light-emitting units above or below the blackbody locus based on the color temperature variation, multiple intersections with the blackbody locus can be determined on the xy chromaticity diagram. Furthermore, by controlling the light output ratio of each light-emitting element group to correspond to chromaticity coordinates along the blackbody locus, color deviation of the illumination light from the blackbody locus can be reduced. This enables color reproduction with light colors close to the blackbody locus, improving the naturalness and comfort of the illumination light. Furthermore, since there is no need to increase the number of light source colors of the light-emitting elements, increases in manufacturing costs and parts management manpower can be suppressed.

[0064] Furthermore, a light emitting element of a central rank may be used as the first light emitting element 60 or the second light emitting element 70 that is not classified according to variation in color temperature. The central rank is a light source group that is made to approach the blackbody locus by using multiple light sources with variation in light color at a constant color temperature (for example, 5000 [K] or 3000 [K]), or a light source group that is made to approach the blackbody locus by selecting light sources with light color variation that are close to the blackbody locus from light sources with light color variation.

[0065] 18 is a diagram illustrating a method for calculating multiple intersections between the blackbody locus and a line connecting the chromaticity coordinates on the first line L1 and the second chromaticity coordinates in a modification of the second embodiment. FIG. 18 shows an example in which a center-ranked light-emitting element is used as the second light-emitting element 70. When a center-ranked light-emitting element is used as the second light-emitting element 70, the second chromaticity coordinates (xo2, yo2) are set as values ​​on the blackbody locus. In FIG. 18, the line connecting the chromaticity coordinates on the first line L1 and the second chromaticity coordinates (xo2, yo2) is moved like a seesaw with the second chromaticity coordinates (xo2, yo2) as a fulcrum to determine the intersections with the blackbody locus.

[0066] The control unit 331 calculates a line L21 connecting the second chromaticity coordinates (xo2, yo2) and the upper first chromaticity coordinates (x11, y11), as shown in FIG. 18. One end of the line L21 is fixed at the second chromaticity coordinates (xo2, yo2), and the other end of the line L21 is moved from the upper first chromaticity coordinates (x11, y11) along the first line L1 to the lower first chromaticity coordinates (x12, y12) to find multiple intersections with the blackbody locus. In other words, in FIG. 18, the control unit 331 finds multiple intersections between the blackbody locus and multiple lines connecting the second chromaticity coordinates (xo2, yo2) and each chromaticity coordinate on the first line L1.

[0067] By using a centrally ranked light emitting element as in this modification, it is possible to realize a light color within the range of region Rs close to the blackbody locus, thereby suppressing deviation of the light color of the illumination light from the blackbody locus, as in the second embodiment.

[0068] Although the above is a description of the embodiments, the present disclosure is not limited to the above embodiments and can be modified in various ways without departing from the spirit of the present disclosure. For example, the configuration and use of the lighting device 100 are not limited to those of the first embodiment and may be various configurations and uses such as facility lighting, general household lighting, or store lighting. Furthermore, the installation environment of the lighting device 100 is not particularly limited and may be indoors, outdoors, or for special purposes (such as a salt-resistant type, high-temperature type, or low-temperature type).

[0069] Furthermore, in the above embodiment, the luminous flux and chromaticity coordinates are corrected according to the temperature of the light source module 5. However, in addition to or instead of the temperature, the luminous flux and standard chromaticity coordinates may be corrected based on deterioration information of the lighting device 100. In this case, the cumulative lighting time of the lighting device 100 is measured, and the measured cumulative lighting time is stored as deterioration information in the storage unit 332 of the control circuit 33. Then, the luminous flux and chromaticity coordinates may be corrected according to the cumulative lighting time.

[0070] In the above embodiment, the color-matching table is generated after correcting the luminous flux and standard chromaticity coordinates of each light-emitting element group in accordance with the temperature of the light source module 5 during use of the lighting device 100. However, the present disclosure is not limited to this embodiment. If the specifications of the lighting device 100 do not require consideration of temperature characteristics, a color-matching table may be generated based on the luminous flux and standard chromaticity coordinates of each light-emitting element group during manufacturing of the lighting device 100, and stored in the memory unit 332 of the control circuit 33.

[0071] In addition, in the above embodiment, the light output ratio between the upper light-emitting element group and the lower light-emitting element group is controlled using a switch element, but the present disclosure is not limited to this. If flicker in moving images or the like is a concern, a lighting circuit 32 may be provided independently for each light-emitting element group to enable DC drive. In this case, the light output ratio of each light-emitting element group can be controlled by controlling the ratio of the current supplied from each lighting circuit 32 to each light-emitting element group. [Explanation of symbols]

[0072] REFERENCE SIGNS LIST 1 fixture body, 3 power supply unit, 4 terminal block, 5, 5A light source module, 6 first light-emitting unit, 7, 7A second light-emitting unit, 8 temperature sensor, 11 main body frame, 12 lens, 13 heat dissipation unit, 21 mounting frame, 22 mounting spring, 23 power supply mounting spring, 24 power supply cover, 25 power supply cable, 31 AC / DC converter, 32 lighting circuit, 33 control circuit, 51 board, 60 first light-emitting element, 61 upper first light-emitting element group, 62 lower first light-emitting element group, 63 upper switch element, 64 lower switch element, 70 second light-emitting element, 71 upper second light-emitting element group, 72 lower second light-emitting element group, 73 upper switch element, 74 lower switch element, 100 lighting device, 321 first lighting circuit, 322 second lighting circuit, 331 control unit, 332 memory unit, 610 Upper first light emitting element, 620 lower first light emitting element, 710 upper second light emitting element, 720 lower second light emitting element.

Claims

1. a first light-emitting unit having a plurality of first light-emitting elements; a second light-emitting unit having a plurality of second light-emitting elements and a color temperature different from that of the first light-emitting unit; a control circuit that controls the outputs of the first light-emitting unit and the second light-emitting unit; Equipped with the plurality of first light-emitting elements are classified into an upper first light-emitting element group having a y value on the xy chromaticity diagram higher than the blackbody locus and a lower first light-emitting element group having a y value on the xy chromaticity diagram lower than the blackbody locus; The control circuit controls the light output ratio between the upper first light-emitting element group and the lower first light-emitting element group.

2. the plurality of second light-emitting elements are classified into an upper second light-emitting element group having a y value on the xy chromaticity diagram higher than the blackbody locus and a lower second light-emitting element group having a y value on the xy chromaticity diagram lower than the blackbody locus, The lighting device according to claim 1 , wherein the control circuit controls a light output ratio between the second upper light-emitting element group and the second lower light-emitting element group.

3. In the xy chromaticity diagram, the y value of a line connecting the chromaticity coordinates of the upper first light-emitting element group and the chromaticity coordinates of the upper second light-emitting element group is higher than the y value of the blackbody locus; 3. The lighting device according to claim 2, wherein in an xy chromaticity diagram, the y value of a straight line connecting the chromaticity coordinates of the lower first group of light-emitting elements and the chromaticity coordinates of the lower second group of light-emitting elements is lower than the y value of the blackbody locus.

4. The control circuit In an xy chromaticity diagram, a first line connecting the chromaticity coordinates of the upper first light-emitting element group and the chromaticity coordinates of the lower first light-emitting element group and a second line connecting the chromaticity coordinates of the upper second light-emitting element group and the chromaticity coordinates of the lower second light-emitting element group are determined; determining a plurality of intersections between a line connecting the chromaticity coordinates on the first line and the chromaticity coordinates on the second line and a blackbody locus; 4. The lighting device according to claim 2, further comprising: a table or a formula based on the chromaticity coordinates of a plurality of the intersections and the chromaticity coordinates on the first straight line and the chromaticity coordinates on the second straight line corresponding to the chromaticity coordinates of each intersection.

5. 5. The lighting device of claim 4, wherein the table includes chromaticity coordinates of a plurality of the intersections, an optical output ratio between the upper first group of light-emitting elements and the lower first group of light-emitting elements corresponding to the chromaticity coordinates of each intersection, and an optical output ratio between the upper second group of light-emitting elements and the lower second group of light-emitting elements.

6. The control circuit determining a first line connecting the chromaticity coordinates of the upper first light-emitting element group and the chromaticity coordinates of the lower first light-emitting element group in an xy chromaticity diagram; determining a plurality of intersections between a blackbody locus and a line connecting the chromaticity coordinates on the first line and the chromaticity coordinates of the second light-emitting unit; 2. The lighting device according to claim 1, further comprising: a table or a formula stored therein based on the chromaticity coordinates of a plurality of the intersections and the chromaticity coordinates on the first straight line corresponding to the chromaticity coordinates of the intersections.

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