Illumination apparatus

Abstract

To provide an illumination apparatus capable of easily projecting light into an exterior space in a light emission pattern suited to the lighting application.SOLUTION: An illumination apparatus 100 includes multiple light sources 1 and a control unit 2. The multiple light sources 1 are mounted on a board, and each one projects light into the exterior space. The control unit 2 controls the multiple light sources 1. The control unit 2 has multiple control elements that are connected one-to-one to the multiple light sources 1, and by individually controlling multiple control elements, at least one of the voltage and current supplied to multiple light sources 1 is individually controlled. The control unit 2 is configured to supply a first current I1 through a first current channel Ch1 for each of the multiple light sources 1.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

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

[0003] [Patent Document 1] Patent No. 5519182 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides an illumination device that can easily project light into an external space in an emission pattern according to the illumination purpose by making it possible to individually supply a relatively large current to a plurality of light sources. [Means for solving the problem]

[0005] An illumination device according to an 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 to the plurality of light sources in a one-to-one relationship, 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. 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. Effect of the Invention

[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 the illumination. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a circuit diagram showing an overview of a lighting device according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing an outline of a mounting area of ​​a plurality of light sources on a substrate of the lighting device according to the embodiment. [Diagram 3] FIG. 3 is a diagram showing an outline of a mounting portion of a light source of the lighting device according to the embodiment. [Figure 4] FIG. 4 is a circuit diagram showing an outline of an internal configuration of a control unit of the lighting device according to the embodiment. [Diagram 5] FIG. 5 is a circuit diagram illustrating another example of the general internal configuration of the control unit of the lighting device according to the embodiment. [Figure 6] FIG. 6 is a diagram showing an overview of a space in which a lighting device of a comparative example is installed. [Figure 7] FIG. 7 is a diagram showing an outline of a space in which a lighting device according to an embodiment is installed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0009] In addition, each figure is a schematic diagram and is not necessarily illustrated precisely. Therefore, for example, the scales in each figure do not necessarily match. In addition, in each figure, substantially the same configurations are given the same reference numerals, and duplicated explanations are omitted or simplified.

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

[0011] (Embodiment) [composition] 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 device (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 the embodiment, the multiple light sources 1 are all light-emitting elements, and are arranged in an array on one surface of the substrate 6. The multiple light sources 1 emit light when a current is supplied from a power source 3 by the control unit 2. Each of the multiple light sources 1 is controlled by the control unit 2 independently of the others (i.e., individually). The control of the light source 1 here includes, for example, turning on or off the light source 1, or adjusting the light emission intensity (in other words, brightness) when the light source 1 is turned on. This allows the multiple light sources 1 to emit light in 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 light emission pattern P1 that is constant over time) or a moving image (i.e., a light emission pattern P1 that changes over time).

[0014] Each of the multiple light sources 1 is, for example, a μLED. The μLED is, for example, a fine LED with a size of 100 μm×100 μm or less. The μLED emits light by a current supplied from the power source 3 by the 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 to emit yellow light. The μLED emits white light as a mixture of blue light and yellow light. The color of the light emitted by the μLED is not particularly limited.

[0015] The 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 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 light sources 1.

[0016] In the embodiment, the thermal conductivity of the substrate 6 is desirably 1 W / m·K or more so that the substrate 6 has better heat dissipation than a glass epoxy substrate. As described later, the light sources 1 are arranged relatively densely on the substrate 6. Also, as described later, a current larger than the current supplied to a light source in a lighting device for backlight use flows through each of the light sources 1. Therefore, the amount of heat generated by the light sources 1 is larger than the amount of heat generated by a lighting device for backlight use. 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 light sources 1, and it becomes easier to improve the durability of each of the 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] Fig. 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 one side measuring several mm. As shown in Fig. 2, the plurality of light sources 1 are mounted in the mounting area 61 of the substrate 6 as an array 10 in which tens to hundreds of light sources 1 are arranged side by side in each row and column.

[0019] In the embodiment, the area of ​​the array 10 occupies 40% or more of the area of ​​the mounting area 61. In other words, the multiple light sources 1 occupy 40% or more of the mounting area 61. This allows the multiple light sources 1 to be arranged relatively densely, making it easier to improve the brightness in the irradiation area of ​​the light projected from each of the multiple light sources 1.

[0020] The proportion of the mounting area 61 occupied by the multiple 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 the embodiment, each of the multiple light sources 1 is, for example, a surface-mounted chip LED, and the bottom surface of the package is mounted on one surface of a 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 multiple light sources 1 (in other words, the surface mounted on the substrate 6). The mounting portion 12 is, for example, a portion mounted on the substrate 6 by soldering, and is a rectangular region here.

[0022] In the embodiment, the area of ​​the mounting portion 12 of each of the multiple 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 for each of the multiple light sources 1 to efficiently dissipate heat generated by the light source 1, and therefore makes it easier to improve the durability of each of the multiple light sources 1.

[0023] The control unit 2 is a processing circuit that controls the multiple light sources 1. In the 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 in which a program is stored, 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 pattern P1 of the multiple light sources 1, and individually controls at least one of the voltage and the current supplied to each of the multiple light sources 1 based on the acquired input data. As a result, the light emission pattern P1 of the multiple light sources 1 is projected into the external space Sp1. The control unit 2 may acquire the input data by receiving input data transmitted from an external device via a communication interface provided in the control unit 2 or external to the control unit 2. The control unit 2 may also acquire the input data by reading out input data stored in a memory provided in the control unit 2 or an external storage device.

[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 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 (described later).

[0027] 5 is a circuit diagram showing another example of the general internal configuration of the control unit 2 of the lighting device 100 according to the embodiment. In the example shown 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, due to the generation of high-frequency components caused by a sudden change in the amplitude of the relatively large current, an excessive electrical load may be applied to the light source 1, which may affect 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 it 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 multiple light sources 1 via a first current channel Ch1. The first current channel Ch1 is a current path that supplies a current from a power source 3 to a corresponding light source 1. In the embodiment, in the first current channel Ch1, a corresponding current amplifying element 5 is inserted between the power source 3 and the corresponding light source 1.

[0029] In the embodiment, the lighting device 100 includes a plurality of current amplifying elements 5 connected to a plurality of light sources 1 in a one-to-one relationship, as shown in Fig. 1. All of the plurality of current amplifying elements 5 are PNP-type bipolar transistors. Each of the plurality of current amplifying 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 that supplies a current from the control unit 2 to the base of the corresponding current amplifying element 5.

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

[0031] That is, in the embodiment, when any one of the control elements 4 is turned on, the second current I2 is supplied to the base of the corresponding current amplifier element 5 via the second current channel Ch2 corresponding to the control element 4. As a result, the first current I1 obtained by amplifying the second current I2 is supplied to the light source 1 corresponding to the control element 4 via the corresponding first current channel Ch1. On the other hand, when the control element 4 is turned off, the second current I2 supplied to the base of the corresponding current amplifier element 5 via the second current channel Ch2 corresponding to the control element 4 is cut off. As a result, the first current I1 supplied to the light source 1 corresponding to the 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 a lighting device for backlight use, for example, 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 addition, 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 a performance capable of supplying a current of the same magnitude as the current supplied to a light source in a lighting device for backlight use, for example. Note that 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 addition, for example, the magnitude of the second current I2 may be 10 to 90% or less of the magnitude of the first current I1.

[0034] The control unit 2, for example, individually controls the multiple 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, it is possible to adjust the emission intensity of each light source 1 and realize a dimming function.

[0035] The method of controlling each of the multiple 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 the multiple light sources 1 by individually controlling the multiple control elements 4. In this way, it is possible to adjust the emission intensity of each light source 1 and achieve a dimming function by adjusting the magnitude of the first current I1 supplied to the multiple light sources 1.

[0036] [advantage] Hereinafter, advantages of the lighting device 100 according to the embodiment will be described 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. 6 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] In the illumination device 200 of the comparative example, only on / off control of the light source is possible, and therefore only one type of light emission pattern is available. Therefore, in an external space Sp1 in which the illumination device 200 of the comparative example is installed, when it is desired to illuminate the external space Sp1 with various light emission patterns, a problem arises in that a plurality of illumination devices 200 of the comparative example must be installed 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 external space Sp1 in which a 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 external space Sp1.

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

[0040] 7, the lighting device 100 illuminates the external space Sp1 with any one of three lighting patterns P1, namely, a first lighting pattern P11, a second lighting pattern P12, and a third lighting pattern P13. In this manner, the lighting device 100 according to the embodiment can illuminate the external space Sp1 with various lighting patterns P1, and therefore does not need to install a plurality of lighting devices 100 as in the lighting device 200 of the comparative example.

[0041] [Variations] Although the embodiment has been described above, the present invention is not limited to the above embodiment. Modifications of the embodiment will be 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 larger than a μLED, such as a general-sized LED. The light source 1 may be an organic EL (Electro-Luminescence) element or a laser element.

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

[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 only needs to have a function of amplifying the second current I2 supplied via the second current channel Ch2.

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

[0046] Also, 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 multiple light sources 1 onto a projection surface such as a wall, a floor, a stage, or a screen. This allows the light emission pattern of the multiple light sources 1 to be projected onto the projection surface. The projection lens may be composed of multiple lenses, or may be composed of a single lens.

[0047] Also, 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. Also, the processor that executes the above program may be single or multiple. That is, centralized processing or distributed processing may be performed.

[0048] In the above embodiment, all or part 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 a 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 the one or more electronic circuits 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 into one chip or into multiple chips. Here, we refer to it as an IC or an LSI, but depending on the degree of integration, it 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 may think of, and forms realized by arbitrarily combining the components and functions of each embodiment within the scope that does not deviate from the spirit 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 of them projects 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 a voltage and a 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] According to such a lighting device 100, since the multiple light sources 1 can be controlled individually, there is an advantage that it is easy to project light into the external space Sp1 in a light emission pattern P1 according to the lighting purpose.

[0054] Also, 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] According to such an illumination device 100, since a current larger than that supplied to a light source in an illumination device for backlight use is supplied to each of the multiple light sources 1, there is an advantage that the external space Sp1 can be easily illuminated with sufficient brightness for illumination use. In other words, the illumination device 100 can supply a relatively large current to each of the multiple light sources (here, LEDs) individually.

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

[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] Also, 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 controlling the current of the plurality of light sources 1 individually.

[0059] Such a lighting device 100 has an advantage that it is easier to control the multiple light sources 1 with a simple configuration, compared to a case where the multiple light sources 1 are individually PWM-controlled.

[0060] Also, for example, the lighting device 100 according to a fifth aspect, in any one of the first to fourth aspects, further includes a plurality of current amplifying elements 5 connected one-to-one to the plurality of light sources 1. Each of the plurality of current amplifying elements 5 supplies the first current I1 to the corresponding light source 1 by amplifying a second current I2 smaller than the first current I1 supplied from the control unit 2 via a second current channel Ch2.

[0061] Such an illumination 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 a performance capable of supplying a current of the same magnitude as the current supplied to a light source in an illumination device used for backlighting, for example.

[0062] Furthermore, for example, in the lighting device 100 according to the 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] Such an illumination device 100 has the advantage that the heat generated by the plurality of light sources 1 can be easily dissipated efficiently, and therefore the durability of each of the plurality of light sources 1 can be easily improved.

[0064] Furthermore, for example, in the illumination device 100 according to a seventh aspect, in any one of the first to sixth aspects, each of the multiple 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 lighting device 100 has the advantage that the heat generated by each of the plurality of light sources 1 can be easily dissipated efficiently, and therefore the durability of each of the plurality of light sources 1 can be easily improved.

[0066] Furthermore, for example, in the lighting device 100 according to an 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] According to such an illumination device 100, since the multiple light sources 1 can be arranged relatively closely together, there is an advantage that the brightness in the illumination area of ​​the light projected from each of the multiple light sources 1 can be easily improved. [Explanation of symbols]

[0068] 1 light source 2. Control section 4 Control elements 5 Current Amplification Element 6 Substrate 11 Bottom surface (the surface that is mounted on the board) 12 Implementation 61 Mounting Area 100 Lighting Equipment Ch1 First current channel Ch2 Second current channel I1 1st current I2 2nd current Sp1 External space

Claims

1. A plurality of light sources mounted on a substrate, each of which projects light into an external space; A control unit that controls the plurality of light sources, the control unit has a plurality of control elements connected to the plurality of light sources in a one-to-one relationship, and 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; The control unit is configured to supply a first current to each of the plurality of light sources via a first current channel. Lighting equipment.

2. The first current is equal to or greater than 50 mA.

10. The lighting device of claim 1.

3. The control unit individually controls the plurality of control elements to individually PWM-control the plurality of light sources.

3. The lighting device according to claim 1 or 2.

4. The control unit individually controls the control elements to individually control the currents of the light sources.

3. The lighting device according to claim 1 or 2.

5. a plurality of current amplifying elements respectively connected to the plurality of light sources in a one-to-one relationship; each of the plurality of current amplifying elements amplifies 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; 3. The lighting device according to claim 1 or 2.

6. The thermal conductivity of the substrate is 1 W / m K or more.

3. The lighting device according to claim 1 or 2.

7. Each of the plurality of light sources has a mounting portion that is directly mounted on the substrate, The mounting portion occupies 30% or more of the surface to be mounted on the substrate.

3. The lighting device according to claim 1 or 2.

8. One surface of the substrate has a mounting area in which the plurality of light sources can be mounted, The plurality of light sources occupy 40% or more of the mounting area.

3. The lighting device according to claim 1 or 2.

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