Lighting devices and lighting fixtures

Abstract

The challenge addressed in this disclosure is to easily switch between protection against surge voltages and protection against continuous high voltage application. [Solution] The lighting device comprises a surge protection circuit 10, a filter circuit 11, a power conversion circuit, a printed circuit board, a metal case, and a switching unit 4. The surge protection circuit 10 is electrically connected to an external power supply. The filter circuit 11 is electrically connected to the surge protection circuit 10. The case houses the printed circuit board. The switching unit 4 selectively switches between a conductive state, which electrically connects the surge protection circuit 10 and the case, and a non-conductive state, which does not electrically connect them. The surge protection circuit 10 has a surge protection element (arrester 100) that is electrically connected to the case via the switching unit 4.

Description

Technical Field

[0001] The present disclosure relates to a lighting device and a lighting fixture, and more particularly, to a lighting device provided with a surge protection element and a lighting fixture provided with the lighting device.

Background Art

[0002] As a conventional example, a lighting device described in Patent Document 1 is exemplified.

[0003] The lighting device described in Patent Document 1 (hereinafter referred to as a conventional example) includes an input circuit that converts AC power supplied from an AC power source into DC power, and a lighting control circuit that causes a light emitting unit to emit light (light up) by the DC power supplied from the input circuit.

[0004] The input circuit has a surge protection element circuit to protect the circuit from a surge voltage such as a lightning surge. The surge protection element circuit includes a first surge protection element and a second surge protection element connected in series between input terminals of an AC voltage, and a third surge protection element having one end connected to an intermediate portion of these surge protection elements and the other end connected to an earth line. When a surge voltage is applied between the input terminals, the surge protection element circuit protects the lighting control circuit and the like by causing the first surge protection element or the second surge protection element and the third surge protection element to switch from a non-conductive state to a conductive state, and flowing the surge voltage to the earth line.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, while varistors and arresters used in surge protection elements are suitable for protecting circuits from surge voltages such as lightning surges, they may fail before switching from a non-conductive state to a conductive state if a high voltage is continuously applied for, for example, 1 second to 1 minute or more. Examples of situations where a high voltage is continuously applied to a surge protection element circuit include testing during the manufacturing process of lighting devices.

[0007] The purpose of this disclosure is to provide lighting devices and luminaires that allow for easy switching between protection against surge voltages and protection against continuous high voltage application. [Means for solving the problem]

[0008] A lighting device according to one aspect of the present disclosure comprises a surge protection circuit, a filter circuit, a power conversion circuit, a printed circuit board, a metal case, and a switching unit. The surge protection circuit is electrically connected to an external power source. The filter circuit is electrically connected to the surge protection circuit. The power conversion circuit converts AC power supplied from the external power source via the filter circuit into DC power and supplies it to a light source. The printed circuit board forms the surge protection circuit, the filter circuit, and the power conversion circuit. The case houses the printed circuit board. The switching unit selectively switches between a conductive state, which electrically connects the surge protection circuit and the case, and a non-conductive state, which does not electrically connect them. The surge protection circuit has a surge protection element that is electrically connected to the case via the switching unit.

[0009] A lighting fixture according to one aspect of this disclosure comprises a lighting device and a light source that is lit by the lighting device. [Effects of the Invention]

[0010] The lighting devices and luminaires of this disclosure have the effect of allowing easy switching between protection against surge voltages and protection against continuous application of high voltages. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a circuit block diagram of a lighting device and lighting fixture according to an embodiment of the present disclosure. [Figure 2] Figure 2 is a circuit diagram of the surge protection circuit and filter circuit in the same lighting device. [Figure 3] Figure 3 is a side view of the same lighting device. [Figure 4] Figure 4 is a front view of the same lighting device. [Figure 5] Figure 5 is a partially abbreviated front view of the same lighting device with the cover removed. [Figure 6] Figure 6 is a partially omitted side view of the same lighting device. [Modes for carrying out the invention]

[0012] Hereinafter, lighting devices and luminaires according to embodiments of this disclosure will be described in detail with reference to the drawings. However, the figures described in the following embodiments are schematic diagrams, and the ratios of the size and thickness of each component do not necessarily reflect the actual dimensional ratios. Furthermore, the configurations described in the following embodiments are merely examples of this disclosure. This disclosure is not limited to the following embodiments, and various modifications are possible depending on the design, etc., as long as the effects of this disclosure can be achieved.

[0013] (1) Overview The lighting fixture A1 according to this embodiment comprises a lighting device 1 according to this embodiment and a light source 5 that is lit by the lighting device 1 according to this embodiment (see Figure 1).

[0014] The lighting fixture A1 according to this embodiment is, for example, a lighting fixture installed inside a tunnel to provide tunnel illumination. However, the lighting fixture A1 according to this embodiment may also be a lighting fixture such as a street light installed on a lighting pole to provide road illumination.

[0015] The light source 5 has a light-emitting element such as an LED. However, the light source 5 may have a light-emitting element other than an LED, such as an organic electroluminescence element or a semiconductor laser element.

[0016] The lighting device 1 according to the embodiment includes a surge protection circuit 10, a filter circuit 11, a power conversion circuit 12, a printed circuit board 2, a metal case 3, and a switching unit 4 (see FIGS. 1 - 4).

[0017] The surge protection circuit 10 is electrically connected to an external power supply P1. The external power supply P1 supplies, for example, a sine-wave AC voltage with an effective value of 100V to 500V. The surge protection circuit 10 has a plurality of surge protection elements. The plurality of surge protection elements include, for example, three varistors 101, 102, 103 and one arrester 100 (see FIG. 2). Note that the arrester 100 is electrically connected to the case 3 via the switching unit 4. However, a varistor may be used instead of the arrester as the surge protection element electrically connected to the case 3 via the switching unit 4.

[0018] The filter circuit 11 is electrically connected to the surge protection circuit 10. Note that the filter circuit 11 is preferably configured to reduce two types of noise, namely normal-mode noise and common-mode noise.

[0019] The power conversion circuit 12 converts the AC power supplied from the external power supply P1 via the filter circuit 11 into DC power and supplies it to the light source 5. The power conversion circuit 12 has, for example, a full-wave rectifier such as a diode bridge, a power factor correction circuit such as a boost chopper circuit, and a buck chopper circuit.

[0020] The printed circuit board 2 forms the surge protection circuit 10, the filter circuit 11, and the power conversion circuit 12. The printed circuit board 2 has a rectangular printed wiring board 20 on which printed wiring is formed, and a large number of circuit components mounted on the printed wiring board 20 (see FIG. 5).

[0021] Case 3 is formed in the shape of a long box from a metal plate (see Figure 3). Case 3 houses the printed circuit board 2. However, both ends of the printed circuit board 2 in the longitudinal direction are exposed from Case 3 at both ends of Case 3 in the longitudinal direction (see Figure 4).

[0022] The switching unit 4 selectively switches between a conductive state, which electrically connects the surge protection circuit 10 and case 3, and a non-conductive state, which electrically disconnects them. Case 3 is electrically and mechanically connected to the metal housing of lighting fixture A1. Furthermore, the housing of lighting fixture A1 is grounded. Therefore, when the switching unit 4 is switched to the conductive state, the surge protection circuit 10 is grounded via the arrester 100.

[0023] However, the lighting device 1 according to the embodiment can protect the circuits (filter circuit 11, power conversion circuit 12, etc.) from surge voltages input through the power supply path from the external power source P1 by the surge protection circuit 10 by switching the switching unit 4 to a conductive state. Furthermore, the lighting device 1 according to the embodiment can reduce the possibility of the surge protection circuit 10 failing when, for example, a high voltage is continuously applied for 1 second to 1 minute or more by switching the switching unit 4 to a non-conductive state. As a result, the lighting device 1 and the lighting fixture A1 according to the embodiment have the advantage of being able to easily switch between protection against surge voltages and protection against continuous application of high voltages.

[0024] (2)Details Next, the lighting fixture A1 (hereinafter abbreviated as lighting fixture A1) and the lighting device 1 (hereinafter abbreviated as lighting device 1) according to the embodiment will be described in detail.

[0025] (2-1) Lighting fixtures Lighting fixture A1 is a lighting fixture installed inside a tunnel to provide tunnel illumination. Lighting fixture A1 consists of a light source 5 and a lighting device 1 housed in a metal casing. The casing of lighting fixture A1 also has a waterproof structure to prevent the ingress of rainwater and other elements.

[0026] Light source 5 may have, for example, an LED module with multiple LEDs mounted on a substrate. However, in Figure 1, only one LED is shown as light source 5.

[0027] (2-2) Lighting device The lighting device 1 comprises a surge protection circuit 10, a filter circuit 11, a power conversion circuit 12, a printed circuit board 2, a metal case 3, and a switching unit 4 (see Figures 1-4). The lighting device 1 further comprises a first input terminal 13 and a second input terminal 14 that are electrically connected to an external power supply P1 (see Figure 1).

[0028] The first input terminal 13 and the second input terminal 14 are so-called quick-connect terminals (also called screwless terminals). The first input terminal 13 and the second input terminal 14 are mounted on the longitudinal ends of the printed circuit board 20 (see Figures 3 and 4). The first input terminal 13 and the second input terminal 14 are electrically connected to the positive and negative terminals of the external power supply P1 via a power cable. In other words, the AC voltage of the external power supply P1 (a sinusoidal AC voltage with an effective value of 100V to 500V) is applied between the first input terminal 13 and the second input terminal 14.

[0029] Furthermore, the first input terminal 13 is electrically connected to the first circuit 21 formed on the printed circuit board 20, and the second input terminal 14 is electrically connected to the second circuit 22, also formed on the printed circuit board 20 (see Figure 2). The first input terminal 13 is electrically connected to the surge protection circuit 10 via a fuse F1 inserted in the first circuit 21.

[0030] The surge protection circuit 10 has multiple surge protection elements (three varistors 101, 102, and 103 and one arrester 100). One end of varistor 102 is electrically connected to the first circuit 21, and the other end of varistor 102 is electrically connected to one end of varistor 103. The other end of varistor 103 is electrically connected to the second circuit 22. Furthermore, one end of varistor 101 is electrically connected to the first circuit 21, and the other end of varistor 101 is electrically connected to the second circuit 22. One end of arrester 100 is electrically connected to the connection point of the two varistors 102 and 103. The other end of arrester 100 is electrically connected to the switching unit 4. The surge protection elements of the surge protection circuit 10 are mounted on one end of the printed circuit board 20 in the longitudinal direction (the end on which the first input terminal 13 and the second input terminal 14 are mounted) (see Figure 5). A fuse F2 is inserted between the surge protection circuit 10 and the filter circuit 11 in the second circuit 22.

[0031] The filter circuit 11 includes three common-mode choke coils 110, 111, and 112, a pair of normal-mode choke coils L1 and L2, two sets of across-the-line capacitors C1, C2, C3, and C4, two sets of line bypass capacitors C5, C6, C23, and C24, three surge absorption elements 113, 114, and 115, two capacitors C7 and C25, and one inductor L3 (see Figure 2).

[0032] A pair of normal-mode choke coils L1 and L2 are inserted one in the first circuit 21 and one in the second circuit 22. Two common-mode choke coils 110 and 111 are electrically connected in series. The remaining common-mode choke coil 112 is provided at the output terminal of the filter circuit 11. A pair of across-the-line capacitors C1 and C2 and a pair of line bypass capacitors C23 and C24 are inserted between the common-mode choke coil 110 and the pair of normal-mode choke coils L1 and L2. Additionally, another pair of across-the-line capacitors C3 and C4 and another pair of line bypass capacitors C5 and C6 are inserted between the two common-mode choke coils 111 and 112. Furthermore, the connection point of one pair of line bypass capacitors C23 and C24 is electrically connected to case 3 via capacitor C25, and a pair of line bypass capacitors C5 and C6 is electrically connected to case 3 via capacitor C7 and inductor L3. However, the filter circuit 11 can suppress high-frequency noise (common-mode noise) generated in the power conversion circuit 12 using two sets of line bypass capacitors C5, C6 and C23, C24.

[0033] The three surge absorption elements 113, 114, and 115 are inserted one by one between the input and output terminals of the filter circuit 11 in the first circuit 21 and the second circuit 22, and between the output terminals of the filter circuit 11.

[0034] The power conversion circuit 12 converts AC power supplied from the external power supply P1 via the filter circuit 11 into DC power and supplies it to the light source 5. The power conversion circuit 12 includes, for example, a full-wave rectifier such as a diode bridge, a power factor correction circuit such as a boost chopper circuit, and a buck chopper circuit. The filter circuit 11 prevents high-frequency noise (switching noise) generated in the power factor correction circuit and the buck chopper circuit from leaking to the external power supply P1.

[0035] The printed circuit board 2 forms the surge protection circuit 10, the filter circuit 11, and the power conversion circuit 12. The printed circuit board 2 has a rectangular printed circuit board 20 on which printed wiring is formed, and a number of circuit components mounted on the printed circuit board 20 (see Figure 5). As described above, the first input terminal 13, the second input terminal 14, and the varistors 101, 102, 103 and arrester 100 of the surge protection circuit 10 are mounted at one end in the longitudinal direction of the printed circuit board 20 (see Figure 5). However, in Figure 5, the circuit components constituting the filter circuit 11, the power conversion circuit 12, etc. are not shown.

[0036] Case 3 has a body 30 and a cover 31 (see Figures 3-6). The body 30 is formed in a trough shape with a rectangular bottom plate 301 and a pair of side plates 302 that protrude in the thickness direction of the bottom plate 301 from both ends along the longitudinal direction of the bottom plate 301.

[0037] Here, support portions 42 are provided at both ends in the longitudinal direction of the pair of side plates 302. These support portions 42 are formed in a hook shape when viewed from the longitudinal direction of the body 30 (see 3). Furthermore, each support portion 42 is provided with a female threaded portion 420.

[0038] The printed circuit board 2 is placed on these support parts 42, and the threaded portion 411 of the fixing screw 41, which is inserted through a through hole provided in the corner of the printed wiring board 20, is screwed into the female threaded portion 420. In other words, the printed circuit board 2 is supported by multiple support parts 42 and attached to the body 30 while being separated from the bottom plate 301. The capacitor C25 and inductor L3 on the printed circuit board 2 are electrically connected to the case 3 via one of the multiple support parts 42 (the upper right support part 42 in Figure 4) and the fixing screw 41.

[0039] The cover 31 has a rectangular top plate 310, a pair of first side plates 311, and a pair of second side plates 312. The pair of first side plates 311 protrude from both ends along the longitudinal direction of the top plate 310 in the thickness direction of the top plate 310 (see Figures 3 and 6). The pair of second side plates 312 protrude from both ends along the short direction of the top plate 310 in the thickness direction of the top plate 310. Therefore, the cover 31 is formed in the shape of a long box with the surface facing the top plate 310 open.

[0040] The cover 31 is connected to the body 30 by accommodating the pair of side plates 302 of the body 30 between the pair of first side plates 311, thereby forming the case 3 (see Figures 3 and 6). Here, the longitudinal dimension of the cover 31 is shorter than the longitudinal dimension of the body 30 and the longitudinal dimension of the printed circuit board 2. Therefore, both longitudinal ends of the printed circuit board 2 are exposed on the outside of the pair of second side plates 312 of the cover 31 (see Figure 4).

[0041] The switching unit 4 includes a land 40 provided on the printed circuit board 20, one of the multiple support parts 42 provided on the case 3 (the upper left support part 42 in Figure 4), and a fixing screw 41 for fixing the printed circuit board 20 to the support part 42. The land 40 is formed on the surface of the printed circuit board 20 (the surface facing the top plate 310 of the cover 31) around a through hole through which the threaded portion 411 of the fixing screw 41 is inserted (see Figure 4). The land 40 is electrically connected to the arrester 100 of the surge protection circuit 10 by printed wiring (conductors) formed on the printed circuit board 20.

[0042] However, when the threaded portion 411 of the fixing screw 41, which is inserted through the through hole of the printed circuit board 20, is screwed into the female threaded portion 420 of the support portion 42, the head 410 of the fixing screw 41 and the land 40 make contact and conduct electricity. As a result, the land 40 of the printed circuit board 20 and the case 3 are electrically connected via the fixing screw 41. On the other hand, if the fixing screw 41 is removed, the land 40 of the printed circuit board 20 will not conduct electricity with the case 3.

[0043] Therefore, the switching unit 4 can selectively switch between a conductive state, in which the surge protection circuit 10 and the case 3 are electrically connected, and a non-conductive state, in which they are not electrically connected, depending on whether the printed circuit board 2 is fixed by the fixing screws 41. When the switching unit 4 is switched to the non-conductive state, an insulating distance equivalent to the thickness of the printed circuit board 20 (approximately 2 mm to 3 mm) is ensured between the land 40 and the support unit 42.

[0044] (2-3) Advantages of the Embodiment The lighting device 1 can protect circuits (filter circuit 11, power conversion circuit 12, etc.) from surge voltages input through the power supply path (first circuit 21 or second circuit 22) from the external power supply P1 by the surge protection circuit 10, by switching the switching unit 4 to a conductive state.

[0045] On the other hand, the lighting device 1 can reduce the possibility of the surge protection circuit 10 failing when a high voltage is continuously applied for 1 second to 1 minute or more by switching the switching unit 4 to a non-conductive state. A case where a high voltage is continuously applied for 1 second to 1 minute or more is, for example, when a withstand voltage test is performed between the printed circuit board 2 and the metal case 3 during the manufacturing process of the lighting device 1. The lighting device 1 can prevent a potential failure of the surge protection circuit 10 (especially the arrester 100) by undergoing the withstand voltage test with the switching unit 4 in a non-conductive state.

[0046] Here, the lighting device 1 ensures an insulation distance between the land 40 and the support part 42 equal to the thickness of the printed circuit board 20 (approximately 2 mm to 3 mm), thereby preventing dielectric breakdown from occurring between the land 40 and the support part 42 (case 3) during the withstand voltage test.

[0047] As a result, the lighting device 1 can easily switch between protection against surge voltage and protection against continuous high voltage application. Furthermore, since the lighting device 1 is designed to undergo a voltage withstand test by switching the switching unit 4 to a non-conductive state, components with relatively low voltage withstand capabilities can be used as surge protection elements. Consequently, the lighting device 1 can achieve miniaturization of the printed circuit board 2, and consequently, the overall size including the case 3.

[0048] Furthermore, the switching unit 4 is configured to selectively switch between a conductive state, in which the lands 40 formed on the printed circuit board 2 are electrically connected to the case 3, and a non-conductive state, in which the lands 40 are not electrically connected to the case 3. Therefore, the lighting device 1 can form the lands 40 when forming the printed wiring on the printed circuit board 2, thus suppressing the cost increase associated with providing the switching unit 4.

[0049] Furthermore, the switching unit 4 has a head 410 that makes contact and conducts with the land 40, and a threaded portion 411 that is screwed into a female threaded portion 420 provided on the case 3. In other words, the switching unit 4 can make contact and conduct with the land 40 by screwing the male screw, which has a head 410 and a female threaded portion 420, into the female threaded portion 420 of the case 3. Therefore, the lighting device 1 can easily switch between a conductive state and a non-conductive state using a screw. However, the switching unit 4 may also electrically and mechanically connect the land 40 and the case 3 using a rivet or the like instead of a screw. Alternatively, the switching unit 4 may electrically connect the arrester 100 and the case 3 using an electric wire (jumper wire) instead of a screw.

[0050] Here, the switching unit 4 further has a support unit 42 provided on the case 3 to support the printed circuit board 2. The support unit 42 is provided with a female threaded portion 420. Thus, since the lighting device 1 has the female threaded portion 420 of the switching unit 4 on the support unit 42 provided on the case 3 to support the printed circuit board 2, the printed circuit board 2 can be fixed to the case 3 using the screws of the switching unit 4, thereby reducing the number of parts. The lighting device 1 may also have a check land on the printed circuit board 2 that is electrically connected to the land 40 of the switching unit 4. In other words, by measuring the potential difference between the check land and the case 3 using a tester, it is possible to check whether or not the switching unit 4 has been switched to a conductive state.

[0051] (3) Summary A lighting device (1) according to a first aspect of this disclosure comprises a surge protection circuit (10), a filter circuit (11), a power conversion circuit (12), a printed circuit board (2), a metal case (3), and a switching unit (4). The surge protection circuit (10) is electrically connected to an external power supply (P1). The filter circuit (11) is electrically connected to the surge protection circuit (10). The power conversion circuit (12) converts AC power supplied from the external power supply (P1) via the filter circuit (11) into DC power and supplies it to a light source (5). The printed circuit board (2) forms the surge protection circuit (10), the filter circuit (11), and the power conversion circuit (12). The case (3) houses the printed circuit board (2). The switching unit (4) selectively switches between a conductive state, in which the surge protection circuit (10) and the case (3) are electrically connected, and a non-conductive state, in which they are not electrically connected. The surge protection circuit (10) has a surge protection element (arrester 100) that is electrically connected to the case (3) via a switching unit (4).

[0052] The lighting device (1) according to the first embodiment can protect the filter circuit (11), power conversion circuit (12), etc., from surge voltage input through the power supply path from an external power source (P1) by the surge protection circuit (10) by switching the switching unit (4) to a conductive state. Furthermore, the lighting device (1) according to the first embodiment can reduce the possibility of the surge protection circuit (10) failing when, for example, a high voltage is continuously applied for 1 second to 1 minute or more by switching the switching unit (4) to a non-conductive state. As a result, the lighting device (1) according to the first embodiment can easily switch between protection against surge voltage and protection against continuous application of high voltage.

[0053] A lighting device (1) according to a second aspect of the present disclosure can be realized by combining it with the first aspect. In the lighting device (1) according to the second aspect, it is preferable that the switching unit (4) selectively switches between a conductive state in which the land (40) formed on the printed circuit board (2) is electrically connected to the case (3) and a non-conductive state in which the land (40) is not electrically connected to the case (3).

[0054] The lighting device (1) according to the second embodiment allows for the formation of lands (40) when forming printed wiring on the printed circuit board (2), thus reducing the cost increase when providing a switching unit (4).

[0055] A lighting device (1) according to a third aspect of the present disclosure can be realized by combining it with the second aspect. In the lighting device (1) according to the third aspect, the switching part (4) preferably has a head (410) that is in contact with and conductive to the land (40) and a threaded part (411) that is screwed into a threaded part (420) provided on the case (3).

[0056] The lighting device (1) according to the third embodiment allows the switching unit (4) to be easily switched between a conductive state and a non-conductive state using a screw having a head (410) and a threaded portion (411).

[0057] A lighting device (1) according to a fourth aspect of the present disclosure can be realized in combination with a third aspect. In the lighting device (1) according to the fourth aspect, the switching unit (4) preferably further has a support unit (42) provided on the case (3) and supporting a printed circuit board (2). It is preferable that the support unit (42) is provided with a female threaded portion (420).

[0058] In the fourth embodiment, the lighting device (1) is provided with a female thread portion (420) of the switching portion (4) on a support portion (42) that is provided on the case (3) and supports the printed circuit board (2). Therefore, the printed circuit board (2) can be fixed to the case (3) using the switching portion (4), thereby reducing the number of parts.

[0059] A lighting device (1) according to a fifth aspect of this disclosure can be realized in combination with any of the first to fourth aspects. In the lighting device (1) according to the fifth aspect, the filter circuit (11) is preferably electrically connected to the case (3) via one or more capacitors (C7, C25).

[0060] The lighting device (1) according to the fifth embodiment can suppress high-frequency noise (common-mode noise) generated in the power conversion circuit (13) with a filter circuit (11).

[0061] A lighting device (1) according to the sixth aspect of this disclosure can be realized in combination with any of the first to fifth aspects. In the lighting device (1) according to the sixth aspect, it is preferable that the insulation distance between the switching unit (4) and the case (3) is 2 mm or more.

[0062] The lighting device (1) according to the sixth embodiment makes it less likely for dielectric breakdown to occur between the switching unit (4) and the case (3).

[0063] A lighting fixture (A1) according to the seventh aspect of this disclosure comprises a lighting device (1) according to any of the first to sixth aspects, and a light source (5) that is lit by the lighting device (1).

[0064] The lighting fixture (A1) according to the seventh embodiment allows for easy switching between protection against surge voltage and protection against continuous application of high voltage. [Explanation of symbols]

[0065] A1 Lighting fixtures 1. Lighting device 2 Printed circuit boards 3 cases 4. Switching section 5 light source 10. Surge protection circuit 11 Filter Circuit 12 Power Conversion Circuit 40 rand 42 Support part 100 Arrester (surge protection element) 410 Head 411 Threaded part 420 Female thread section C1 Capacitor

Claims

1. A surge protection circuit electrically connected to an external power supply, A filter circuit electrically connected to the surge protection circuit, A power conversion circuit that converts AC power supplied from the external power source via the filter circuit into DC power and supplies it to the light source, A printed circuit board forming the surge protection circuit, the filter circuit, and the power conversion circuit, A metal case for housing the aforementioned printed circuit board, A switching unit that selectively switches between a conductive state, in which the surge protection circuit and the case are electrically connected, and a non-conductive state, Equipped with, The surge protection circuit has a surge protection element that is electrically connected to the case via the switching unit. Lighting device.

2. The switching unit selectively switches between a conductive state in which the land formed on the printed circuit board is electrically connected to the case, and a non-conductive state in which the land is not electrically connected to the case. The lighting device according to claim 1.

3. The switching portion has a head that contacts and conducts with the land, and a threaded portion that is screwed into the threaded portion provided in the case. The lighting device according to claim 2.

4. The switching unit further includes a support unit provided in the case for supporting the printed circuit board, The female threaded portion is provided in the support portion. The lighting device according to claim 3.

5. The filter circuit is electrically connected to the case via one or more capacitors. A lighting device according to any one of claims 1 to 4.

6. The insulation distance between the switching unit and the case is 2 mm or more. A lighting device according to any one of claims 1 to 4.

7. A lighting device according to any one of claims 1-4, A light source that is lit by the aforementioned lighting device, Equipped with, Lighting fixtures.

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