Lighting device

Abstract

A lighting device (100) comprises a plurality of light sources (1) and a control unit (2). The plurality of light sources (1) are mounted on a substrate, and each projects light into an external space. The control unit (2) controls the plurality of light sources (1). The control unit (2) has a plurality of control elements connected one-to-one to the plurality of light sources (1) and individually controls the voltage and / or current supplied to the plurality of light sources (1) by individually controlling the plurality of control elements. The control unit (2) is configured to be capable of supplying a first current (I1) to each of the plurality of light sources (1) via a first current channel (Ch1).

Description

lighting equipment

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

[0002] Patent Document 1 discloses an LED (Light Emitting Diode) drive circuit for an LED array for backlighting a liquid crystal panel.

[0003] Patent No. 5519182

[0004] The present invention provides a lighting device that can easily project light into an external space in a light emission pattern according to the lighting application by being able to individually supply a relatively large current to a plurality of light sources.

[0005] An illumination device according to one aspect of the present invention includes a plurality of light sources and a control unit. The plurality of light sources are mounted on a substrate and each project light into an external space. The control unit controls the plurality of light sources. The control unit has a plurality of control elements connected one-to-one to the plurality of light sources, and controls at least one of the voltage and the current supplied to the plurality of light sources individually by individually controlling the plurality of control elements. The control unit is configured to be able to supply a first current to each of the plurality of light sources via a first current channel.

[0006] According to the present invention, it is possible to supply a relatively large current to a plurality of light sources individually, which has the advantage that it is easy to project light into an external space in a light emission pattern according to the purpose of illumination.

[0007] FIG. 1 is a circuit diagram showing an overview of a lighting device according to an embodiment. FIG. 2 is a diagram showing an overview of mounting areas for a plurality of light sources on a substrate of a lighting device according to an embodiment. FIG. 3 is a diagram showing an overview of a mounting portion of a light source of a lighting device according to an embodiment. FIG. 4 is a circuit diagram showing an overview of the internal configuration of a control unit of a lighting device according to an embodiment. FIG. 5 is a circuit diagram showing another example of the overview of the internal configuration of a control unit of a lighting device according to an embodiment. FIG. 6 is a diagram showing an overview of a space in which a lighting device of a comparative example is installed. FIG. 7 is a diagram showing an overview of a space in which a lighting device according to an embodiment is installed.

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present invention. Therefore, the numerical values, shapes, materials, components, component arrangements and connection forms, steps, step sequences, etc. shown in the following embodiments are merely examples and are not intended to limit the present invention. Therefore, among the components in the following embodiments, components not recited in the independent claims will be described as optional components.

[0009] Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scales and the like do not necessarily match in each figure. Furthermore, in each figure, substantially the same configurations are assigned the same reference numerals, and duplicate explanations are omitted or simplified.

[0010] Furthermore, in this specification, terms indicating the relationship between elements, terms indicating the shape of elements, and numerical ranges are not expressions that only express a strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about a few percent.

[0011] (Embodiment) [Configuration] First, the configuration of an illumination device according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a circuit diagram showing an overview of an illumination device 100 according to an embodiment. As shown in Fig. 1, the illumination device 100 includes a plurality of light sources 1 and a control unit 2.

[0012] In the embodiment, the lighting device 100 is, for example, a spotlight, and is attached to a wiring fixture (for example, a wiring duct or a ceiling hook) provided on a ceiling or a wall. Note that the lighting device 100 is not limited to a spotlight, and may be, for example, a downlight or a ceiling light.

[0013] In this embodiment, the multiple light sources 1 are all light-emitting elements and are arranged in an array on one surface of a substrate 6 (see FIG. 2 ). The multiple light sources 1 emit light when a current is supplied from a power source 3 by a control unit 2. The multiple light sources 1 are each controlled independently (i.e., individually) by the control unit 2. Here, control of the light sources 1 includes, for example, turning on and off the light sources 1, or adjusting the light emission intensity (in other words, brightness) when the light sources 1 are on. This allows the multiple light sources 1 to emit light in accordance with a light emission pattern P1 (see FIG. 7 ) indicated by input data (described later). The light emission pattern P1 may be a still image (i.e., a time-constant light emission pattern P1) or a moving image (i.e., a time-varying light emission pattern P1).

[0014] Each of the multiple light sources 1 is, for example, a μLED. A μLED is a minute LED, for example, with a size of 100 μm × 100 μm or less. The μLED emits light using a current supplied from a power source 3 by a control unit 2. The μLED includes, for example, a blue LED and a yellow phosphor arranged on the light emission side of the blue LED. The yellow phosphor is excited by a portion of the blue light emitted by the blue LED, causing it to emit yellow light. The μLED emits white light as a mixture of blue light and yellow light. Note that the color of the light emitted by the μLED is not particularly limited.

[0015] The plurality of light sources 1 are arranged in a two-dimensional array and mounted on one surface of a substrate 6. The substrate 6 is, for example, a rigid substrate, but may also be a flexible substrate. The substrate 6 is provided with, for example, pattern wiring for supplying current from the control unit 2 and the power source 3 to each of the plurality of light sources 1.

[0016] In this embodiment, the thermal conductivity of the substrate 6 is desirably 1 W / m·K or more to provide better heat dissipation than a glass epoxy substrate. As will be described later, the multiple light sources 1 are arranged relatively densely on the substrate 6. Also, as will be described later, a current larger than the current supplied to a light source in, for example, a lighting device used as a backlight flows through each of the multiple light sources 1. Therefore, the heat generated by the multiple light sources 1 is larger than the heat generated by, for example, a lighting device used as a backlight. Therefore, by setting the thermal conductivity of the substrate 6 to 1 W / m·K or more, it becomes easier to efficiently dissipate the heat generated by the multiple light sources 1, and it becomes easier to improve the durability of each of the multiple light sources 1.

[0017] The thermal conductivity of the substrate 6 may be, for example, 2 W / m·K or more. In another example, the thermal conductivity of the substrate 6 may be 5 W / m·K or more. In yet another example, the thermal conductivity of the substrate 6 may be 10 W / m·K or more.

[0018] 2 is a diagram showing an outline of a mounting area 61 for mounting a plurality of light sources 1 on a substrate 6 of a lighting device 100 according to an embodiment. As shown in Fig. 2, in the embodiment, one surface of the substrate 6 has a mounting area 61 in which a plurality of light sources 1 can be mounted. The mounting area 61 is, for example, a rectangular area with a side length of several millimeters. As shown in Fig. 2, the plurality of light sources 1 are mounted in the mounting area 61 on the substrate 6 as an array 10 in which several tens to several hundreds of light sources 1 are arranged side by side in each row and column.

[0019] In this embodiment, the area of ​​the array 10 occupies 40% or more of the area of ​​the mounting area 61. In other words, the plurality of light sources 1 occupies 40% or more of the mounting area 61. This allows the plurality of light sources 1 to be arranged relatively densely, which makes it easier to improve the brightness of the illumination area of ​​the light projected from each of the plurality of light sources 1.

[0020] The proportion of the mounting area 61 occupied by the light sources 1 may be, for example, 50% or more. In another example, the proportion may be 60% or more. In yet another example, the proportion may be 70% or more.

[0021] Fig. 3 is a diagram showing an outline of a mounting portion 12 of a light source 1 of a lighting device 100 according to an embodiment. In this embodiment, each of the plurality of light sources 1 is, for example, a surface-mounted chip LED, and the bottom surface of the package is mounted on one surface of the substrate 6. As shown in Fig. 3, a mounting portion 12 is provided on the bottom surface 11 of the package of each of the plurality of light sources 1 (in other words, the surface that is mounted on the substrate 6). The mounting portion 12 is a portion that is mounted on the substrate 6 by, for example, soldering, and is a rectangular region in this case.

[0022] In the embodiment, the area of ​​the mounting portion 12 of each of the plurality of light sources 1 occupies 30% or more of the area of ​​the bottom surface of the package of the light source 1. In other words, the mounting portion 12 occupies 30% or more of the surface that is mounted on the substrate 6. This makes it easier to efficiently dissipate heat generated by each of the plurality of light sources 1, which makes it easier to improve the durability of each of the plurality of light sources 1.

[0023] The control unit 2 is a processing circuit that controls the multiple light sources 1. In this embodiment, the control unit 2 is an LED driver, and is realized by, for example, an ASIC (Application Specific Integrated Circuit) and a microcontroller. The microcontroller includes, for example, a non-volatile memory that stores a program, a volatile memory that is a temporary storage area for executing the program, an input / output port, and a processor that executes the program. The program may be stored in an external storage device.

[0024] The control unit 2 acquires input data related to the light emission patterns P1 of the multiple light sources 1, and individually controls at least one of the voltage and current supplied to each of the multiple light sources 1 based on the acquired input data. As a result, the light emission patterns P1 of the multiple light sources 1 are projected into the external space Sp1 (see FIG. 7 ). The control unit 2 may acquire the input data by receiving input data transmitted from an external device via a communication interface included in the control unit 2 or external to the control unit 2, for example. Alternatively, the control unit 2 may acquire the input data by reading out input data stored in a memory included in the control unit 2 or an external storage device, for example.

[0025] Specifically, as shown in Fig. 4, the control unit 2 has a plurality of control elements 4 connected one-to-one to the plurality of light sources 1, and individually controls at least one of the voltage and the current supplied to the plurality of light sources 1 by individually controlling the plurality of control elements 4. Fig. 4 is a circuit diagram showing an outline of the internal configuration of the control unit 2 of the lighting device 100 according to the embodiment. Note that Fig. 4 illustrates only the configuration related to the plurality of control elements 4 out of the internal configuration of the control unit 2.

[0026] The control elements 4 are all depletion-type n-type MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). The on / off state of each of the control elements 4 is controlled by a voltage applied between the gate and source in accordance with input data. Each of the control elements 4 is connected to a corresponding light source 1 via a backflow prevention diode D1 connected between the drain and source. Although not shown in FIG. 4, each of the control elements 4 is connected to a corresponding light source 1 via a corresponding current amplification element 5 (see FIG. 1, described later).

[0027] FIG. 5 is a circuit diagram illustrating another example of the general internal configuration of the control unit 2 of the lighting device 100 according to the embodiment. In the example illustrated in FIG. 5 , a low-pass filter composed of a coil L1 and a capacitor C1 is connected to each of the multiple light sources 1. In the embodiment, a relatively large current may flow through the light source 1. Therefore, high-frequency components caused by abrupt changes in the amplitude of the relatively large current may be generated, placing an excessive electrical load on the light source 1 and potentially affecting the life of the light source 1. Therefore, by connecting a low-pass filter to each of the multiple light sources 1 as described above, the high-frequency components are suppressed, making them less likely to affect the life of the light source 1.

[0028] 1 , the control unit 2 is configured to supply a first current I1 to each of the plurality of light sources 1 via a first current channel Ch1. The first current channel Ch1 is a current path for supplying a current from the power source 3 to the corresponding light source 1. In the embodiment, in the first current channel Ch1, a corresponding current amplification element 5 is inserted between the power source 3 and the corresponding light source 1.

[0029] 1 , the lighting device 100 includes a plurality of current amplifier elements 5 connected one-to-one to a plurality of light sources 1. Each of the current amplifier elements 5 is a PNP bipolar transistor. Each of the current amplifier elements 5 amplifies a second current I2 supplied from the control unit 2 via a second current channel Ch2, thereby supplying a first current I1 to the corresponding light source 1. The second current channel Ch2 is a current path for supplying a current from the control unit 2 to the base of the corresponding current amplifier element 5.

[0030] Specifically, in each of the multiple current amplification elements 5, a second current I2 is supplied to the base from the control unit 2. The second current I2 is a current smaller than the first current I1. Then, in each of the multiple current amplification elements 5, the second current I2 is supplied to the base, and a current obtained by amplifying the second current I2 flows between the emitter and the collector. Therefore, the multiple light sources 1 are each supplied with the first current I1 (the emitter-collector current of the corresponding current amplification element 5) via the corresponding first current channel Ch1.

[0031] That is, in the embodiment, when any one of the multiple control elements 4 is turned on, the second current I2 is supplied to the base of the corresponding current amplification element 5 via the second current channel Ch2 corresponding to that control element 4. As a result, the first current I1, which is obtained by amplifying the second current I2, is supplied to the light source 1 corresponding to that control element 4 via the corresponding first current channel Ch1. On the other hand, when that control element 4 is turned off, the second current I2, which had been supplied to the base of the corresponding current amplification element 5 via the second current channel Ch2 corresponding to that control element 4, is cut off. As a result, the first current I1, which had been supplied to the light source 1 corresponding to that control element 4, is also cut off.

[0032] Here, in the embodiment, the first current I1 is 50 mA or more. That is, in the embodiment, it is possible to supply a current larger than the current supplied to a light source in, for example, a lighting device used as a backlight to each of the multiple light sources 1. Note that the first current I1 may be, for example, 100 mA or more. In another example, the first current I1 may be 500 mA or more. In yet another example, the first current I1 may be 1 A or more.

[0033] In the embodiment, the second current I2 is less than 50 mA. That is, in the embodiment, the control unit 2 can supply the first current I1 to each of the multiple light sources 1 as long as the control unit 2 has the performance to supply a current of the same magnitude as the current supplied to a light source in, for example, a lighting device for backlighting. The second current I2 may be, for example, 40 mA or less. In another example, the second current I2 may be 30 mA or less. In yet another example, the second current I2 may be 20 mA or less. In another example, the magnitude of the second current I2 may be 10 to 90% of the magnitude of the first current I1.

[0034] The control unit 2, for example, individually controls the control elements 4 to individually PWM (Pulse Width Modulation) control the multiple light sources 1. In this way, by adjusting the pulse width (i.e., duty ratio) of the voltage applied to each of the multiple light sources 1 and adjusting the first current I1 supplied thereto, it is possible to adjust the light emission intensity of each light source 1 and achieve a dimming function.

[0035] The method of controlling each of the plurality of light sources 1 by the control unit 2 is not particularly limited to PWM control. For example, the control unit 2 may individually control the current of each of the plurality of light sources 1 by individually controlling the plurality of control elements 4. In this way, it is possible to adjust the light emission intensity of each light source 1 and achieve a dimming function by adjusting the magnitude of the first current I1 supplied to the plurality of light sources 1.

[0036] [Advantages] The advantages of the lighting device 100 according to the embodiment will be described below, along with a comparison with a lighting device 200 of a comparative example. FIG. 6 is a diagram showing an outline of an external space Sp1 in which a lighting device 200 of a comparative example is installed. Here, the external space Sp1 is the inside of a warehouse. In FIG. 7 described later, the external space Sp1 is also the inside of a warehouse. The lighting device 200 of the comparative example is a spotlight, and is a device capable of projecting light into the external space Sp1 with one light source. In the example shown in FIG. 6, a plurality of lighting devices 200 of the comparative example are installed on the ceiling of the external space Sp1.

[0037] The illumination device 200 of the comparative example can only control the on / off of the light source, and therefore has only one type of light emission pattern. Therefore, in an external space Sp1 in which the illumination device 200 of the comparative example is installed, if it is desired to illuminate the external space Sp1 with various light emission patterns, it is necessary to install a plurality of illumination devices 200 of the comparative example as shown in FIG. 6 .

[0038] In contrast, the lighting device 100 according to the embodiment can solve the above problem. Fig. 7 is a diagram showing an outline of an exterior space Sp1 in which the lighting device 100 according to the embodiment is installed. In the example shown in Fig. 7, one lighting device 100 according to the embodiment is installed on the ceiling of the exterior space Sp1.

[0039] In the lighting device 100 according to the embodiment, the control unit 2 individually controls the plurality of control elements 4, thereby individually controlling the plurality of light sources 1. Therefore, the lighting device 100 according to the embodiment has an advantage in that it is easy to project light into the external space Sp1 in a light emission pattern P1 according to the lighting application.

[0040] 7 , the lighting device 100 illuminates the external space Sp1 with one of three lighting patterns P1: a first lighting pattern P11, a second lighting pattern P12, and a third lighting pattern P13. In this way, the lighting device 100 according to the embodiment can illuminate the external space Sp1 with a variety of lighting patterns P1, eliminating the need to install multiple lighting devices 100 as in the lighting device 200 of the comparative example.

[0041] [Modifications] Although the embodiment has been described above, the present invention is not limited to the above embodiment. Modifications of the embodiment are listed below. The modifications described below may be combined as appropriate.

[0042] For example, in the above embodiment, the light source 1 is a μLED, but is not limited to this. The light source 1 may be an LED that is larger than a μLED, such as a general-sized LED. Furthermore, the light source 1 may be an organic electroluminescence (EL) element or a laser element.

[0043] In addition, for example, in the above embodiment, the control element 4 is an n-type depletion MOSFET, but is not limited to this. The control element 4 only needs to be able to directly or indirectly switch whether or not to supply the first current I1 to the corresponding light source 1 via the first current channel Ch1.

[0044] In addition, for example, in the above embodiment, the current amplifying element 5 is a PNP bipolar transistor, but is not limited to this. The current amplifying element 5 may have the function of amplifying the second current I2 supplied via the second current channel Ch2.

[0045] Furthermore, for example, in the above embodiment, the lighting device 100 does not need to include a plurality of current amplification elements 5. In this case, it is sufficient that the control unit 2 has the performance to be able to directly pass the first current I1 through each light source 1 via the first current channel Ch1.

[0046] Furthermore, for example, in the above-described embodiment, the lighting device 100 may further include a projection lens. The projection lens projects light emitted by each of the plurality of light sources 1 onto a projection surface such as a wall, floor, stage, or screen. This allows the light emission patterns of the plurality of light sources 1 to be projected onto the projection surface. The projection lens may be composed of a plurality of lenses or a single lens.

[0047] Furthermore, for example, the processes described in the above embodiments may be realized by centralized processing using a single processing circuit or device, or may be realized by distributed processing using multiple processing circuits or devices. Furthermore, the processor that executes the above program may be a single processor or multiple processors. That is, centralized processing or distributed processing may be performed.

[0048] In the above-described embodiments, all or some of the components such as the control unit may be configured with dedicated hardware, or 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 (Central Processing Unit) or a processor reading and executing a software program recorded on a recording medium such as an HDD (Hard Disk Drive) or a semiconductor memory.

[0049] Furthermore, the components such as the control unit may be configured with one or more electronic circuits, each of which may be a general-purpose circuit or a dedicated circuit.

[0050] The one or more electronic circuits may include, for example, a semiconductor device, an IC, or an LSI. The IC or LSI may be integrated on a single chip or on multiple chips. Although the IC or LSI is referred to here as an IC or LSI, the name may vary depending on the degree of integration, and may be called a system LSI, a VLSI (Very Large Scale Integration), or an ULSI (Ultra Large Scale Integration). Also, an FPGA that is programmed after the LSI is manufactured can be used for the same purpose.

[0051] In addition, the present invention also includes forms obtained by applying various modifications to each embodiment that a person skilled in the art would think of, and forms realized by arbitrarily combining the components and functions of each embodiment within the scope of the present invention.

[0052] (Summary) As described above, the lighting device 100 according to the first aspect includes a plurality of light sources 1 and a control unit 2. The plurality of light sources 1 are mounted on a substrate 6, and each project light into an external space Sp1. The control unit 2 controls the plurality of light sources 1. The control unit 2 has a plurality of control elements 4 connected to the plurality of light sources 1 in a one-to-one relationship, and individually controls at least one of the voltage and the current supplied to the plurality of light sources 1 by individually controlling the plurality of control elements 4. The control unit 2 is configured to be able to supply a first current I1 to each of the plurality of light sources 1 via a first current channel Ch1.

[0053] Such a lighting device 100 has the advantage that it is possible to individually control the multiple light sources 1, making it easy to project light into the external space Sp1 in a light emission pattern P1 that suits the lighting application.

[0054] Furthermore, for example, in the lighting device 100 according to the second aspect, in the first aspect, the first current I1 is 50 mA or more.

[0055] The lighting device 100 supplies a current to each of the plurality of light sources 1 that is larger than the current supplied to a light source in a lighting device used for, for example, a backlight, and therefore has the advantage of easily illuminating the external space Sp1 with sufficient brightness for lighting purposes. In other words, the lighting device 100 can supply a relatively large current to each of the plurality of light sources (here, LEDs) individually.

[0056] Furthermore, for example, in the lighting device 100 according to the third aspect, in the first or second aspect, the control unit 2 individually controls the plurality of control elements 4 to individually PWM-control the plurality of light sources 1.

[0057] Such a lighting device 100 has the advantage that it is easier to reduce the power consumption of each of the multiple light sources 1 and to extend the life of each of the multiple light sources 1, compared to when the current of each of the multiple light sources 1 is controlled individually.

[0058] Furthermore, for example, in the lighting device 100 according to the fourth aspect, in the first or second aspect, the control unit 2 controls the plurality of control elements 4 individually, thereby individually controlling the current of the plurality of light sources 1 .

[0059] The lighting device 100 has an advantage that it is easier to control the plurality of light sources 1 with a simple configuration, compared to when the plurality of light sources 1 are individually PWM controlled.

[0060] Furthermore, for example, the lighting device 100 according to a fifth aspect is the lighting device 100 of any one of the first to fourth aspects, further including a plurality of current amplifiers 5 connected one-to-one to the plurality of light sources 1. Each of the plurality of current amplifiers 5 amplifies a second current I2 that is smaller than the first current I1 supplied from the control unit 2 via the second current channel Ch2, thereby supplying the first current I1 to the corresponding light source 1.

[0061] Such a lighting device 100 has the advantage that it is possible to supply the first current I1 to each of the multiple light sources 1 even if the control unit 2 has the performance to supply a current of the same magnitude as the current supplied to a light source in a lighting device used for backlighting, for example.

[0062] Furthermore, for example, in the lighting device 100 according to a sixth aspect, in any one of the first to fifth aspects, the thermal conductivity of the substrate 6 is 1 W / m·K or more.

[0063] According to such a lighting device 100, the heat generated by the plurality of light sources 1 can be easily dissipated efficiently, which has the advantage that the durability of each of the plurality of light sources 1 can be easily improved.

[0064] Furthermore, for example, in the lighting device 100 according to the seventh aspect, in any one of the first to sixth aspects, each of the plurality of light sources 1 has a mounting portion 12 that is directly mounted on the substrate 6. The mounting portion 12 occupies 30% or more of the surface (bottom surface 11) that is mounted on the substrate 6.

[0065] Such a lighting device 100 has the advantage that it is easy to efficiently dissipate heat generated by each of the plurality of light sources 1, and therefore it is easy to improve the durability of each of the plurality of light sources 1.

[0066] Furthermore, for example, in the lighting device 100 according to the eighth aspect, in any one of the first to seventh aspects, one surface of the substrate 6 has a mounting area 61 in which a plurality of light sources 1 can be mounted. The plurality of light sources 1 occupy 40% or more of the mounting area 61.

[0067] Such an illumination device 100 has the advantage that the plurality of light sources 1 can be arranged relatively densely, making it easier to improve the brightness in the illumination area of ​​the light projected from each of the plurality of light sources 1.

[0068] REFERENCE SIGNS LIST 1 Light source 2 Control unit 4 Control element 5 Current amplification element 6 Substrate 11 Bottom surface (surface mounted on the substrate) 12 Mounting portion 61 Mounting area 100 Lighting device Ch1 First current channel Ch2 Second current channel I1 First current I2 Second current Sp1 External space

Claims

1. A lighting device comprising: a plurality of light sources mounted on a substrate, each of which projects light into an external space; and a control unit which controls the plurality of light sources, wherein the control unit has a plurality of control elements connected one-to-one to the plurality of light sources, and individually controls at least one of a voltage and a current supplied to the plurality of light sources by individually controlling the plurality of control elements, and the control unit is configured to be able to supply a first current to each of the plurality of light sources via a first current channel.

2. The lighting device according to claim 1, wherein the first current is 50 mA or more.

3. The lighting device according to claim 1 or 2, wherein the control unit individually controls the plurality of control elements to individually PWM-control the plurality of light sources.

4. The lighting device according to claim 1 or 2, wherein the control unit individually controls the control elements to individually control currents of the light sources.

5. The lighting device according to claim 1 or 2, further comprising a plurality of current amplifying elements respectively connected in a one-to-one relationship to the plurality of light sources, each of the plurality of current amplifying elements amplifying a second current smaller than the first current supplied from the control unit via a second current channel, thereby supplying the first current to a corresponding light source.

6. The lighting device according to claim 1 or 2, wherein the thermal conductivity of the substrate is 1 W / m·K or more.

7. The lighting device according to claim 1 or 2, wherein each of the plurality of light sources has a mounting portion that is directly mounted on the substrate, and the mounting portion occupies 30% or more of a surface that is mounted on the substrate.

8. The lighting device according to claim 1 or 2, wherein one surface of the substrate has a mounting area capable of mounting the plurality of light sources, and the plurality of light sources occupy 40% or more of the mounting area.

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