JP2021157869A - Light source and lighting fixture - Google Patents

Abstract

To provide a light source and a lighting fixture capable of suppressing the fine lighting.SOLUTION: A light source comprises: an enclosure of a conductor; an insulation layer provided on the enclosure; reverse-side wiring provided on the insulation layer; an insulation substrate provided on the reverse-side wiring and having a through hole formed thereon; a plurality of LED chips provided on the insulation substrate; LED wiring provided on the insulation substrate and connecting the plurality of LED chips to form a circuit; and through wiring provided in the through hole to electrically connect an LED wiring end part serving as a part of an input end or output end of the circuit of the LED wiring with the reverse-side wiring.SELECTED DRAWING: Figure 9

Description

The present disclosure relates to a light source and a luminaire containing the light source.

In a lighting fixture using an LED (Light Emitting Diode) as a light source, it is necessary to convert the energy input from an AC commercial power source into DC energy and output it to the LED. In addition, regulations regarding harmonics of input current are stipulated, and in Japan, limits are set for harmonics of input current by the Japanese Industrial Standards. Therefore, the lighting device has a PFC (Power Factor Correction) circuit which is a power factor improving circuit for suppressing the harmonic of the input current and improving the power factor.

In addition, the lighting device controls the brightness of the LED. Since the brightness of the LED depends on the magnitude of the LED current, the lighting device has a current control circuit that controls the magnitude of the output current to be constant. In particular, the PFC circuit and the current control circuit may be realized by one circuit.

A more specific configuration of the connection between the AC commercial power supply and the lighting equipment will be described. The commercial power source uses a voltage obtained by stepping down the system voltage for power transmission to a voltage of, for example, 200 Vrms via a transformer, and is connected to a lighting fixture. Generally, the secondary side of a transformer has a grounded intermediate potential output terminal and two output terminals having a voltage of 100 Vrms with respect to the intermediate potential, and these three are for luminaires. The potential output terminal is connected.

In this configuration, when a noise voltage is generated at the ground potential, the LED may be slightly lit (slightly lit) even though the operation of the current control circuit is stopped and the LED is turned off. This is because a floating capacitance is formed between the wiring near the LED and the ground potential, so that a closed circuit that generates a noise current is formed due to the noise voltage. When a part of the noise current flows through the LED, slight lighting occurs.

For example, Patent Document 1 discloses a method of connecting a capacitor in parallel with an LED to allow a noise current to flow through the capacitor and make it difficult for the LED to flow as a countermeasure for suppressing slight lighting.

Japanese Unexamined Patent Publication No. 2010-272846

When a capacitor is connected in parallel with the LED as a countermeasure for suppressing faint lighting, a space for mounting the capacitor is required, so that the area of the substrate on which the LED is mounted becomes large. Therefore, in addition to the increase in the number of parts, there is a problem that the cost increases due to the increase in the substrate area. Also, even if a capacitor is connected in parallel with the LED, it is not possible to completely prevent the noise current from flowing to the LED. Therefore, if the noise voltage becomes higher than expected and the noise current becomes large, , Slight lighting occurs.

The present disclosure has been made in order to solve the above-mentioned problems, and an object of the present disclosure is to provide a light source and a lighting fixture capable of suppressing faint lighting.

The light source according to the present disclosure is provided on the housing of the conductor, the insulating layer provided on the housing, the back surface wiring provided on the insulating layer, and the back surface wiring, and penetrates. An insulating substrate having holes formed therein, a plurality of LED chips provided on the insulating substrate, and LED wiring provided on the insulating substrate and connecting the plurality of LED chips to form a circuit. It is provided with a through hole provided in the LED wiring, which is a portion of the LED wiring that becomes an input end or an output end of the circuit, and a through wiring that electrically connects the back surface wiring. It is a feature.

Other features of the disclosure are clarified below.

According to the present disclosure, in the wiring structure facing the LED, the noise current flowing through the LED is reduced and the slight lighting is suppressed by letting the noise current escape to the ground potential. As a result, since slight lighting is suppressed without connecting a capacitor in parallel with the LED, the number of parts can be suppressed and the substrate area can be reduced.

It is a circuit diagram explaining a basic configuration. It is a circuit diagram which shows the flow of the electric current which causes faint lighting. It is a perspective view which shows the structural example of a light source. It is a partial cross-sectional view of FIG. It is a perspective view of the light source which concerns on a comparative example. It is a circuit diagram which shows the flow of the electric current which causes faint lighting. It is a perspective view which shows the structural example of the light source which concerns on Embodiment 1. FIG. It is an exploded perspective view of the light source of FIG. It is a partial cross-sectional view of the light source of FIG. It is a circuit diagram which shows the flow of a current. It is a perspective view of the light source which concerns on Embodiment 2. FIG. It is an exploded perspective view of the light source of FIG. It is a perspective view of the light source which concerns on Embodiment 3. FIG. It is an exploded perspective view of the light source of FIG.

Hereinafter, the light source and the lighting fixture according to the embodiment will be described with reference to the drawings. The same or corresponding parts may be designated by the same reference numerals and the description may be omitted. It should be noted that this disclosure is not limited to the features of the embodiments.

FIG. 1 is a configuration diagram of a lighting device and a lighting fixture for explaining the principle of generating slight lighting. The lighting fixture 11 uses the power supplied from the system voltage 1a as a light source via the input filter 2 which is connected to the system voltage 1a via the transformer 1b and removes the high frequency component of the alternating current output from the system voltage 1a. A lighting device 8 is provided which converts the DC current that can be input to 100 into a DC current and outputs the current. The luminaire 11 further includes a light source 100 that is lit by electric power supplied from the lighting device 8. The light source 100 is composed of an LED group 100a in which a plurality of LEDs are connected in series or in parallel by at least one method. One end of the LED group is connected to the positive electrode side DC bus of the lighting device 8 via the positive electrode side connection terminal 100c, and the other end of the LED group is connected to the negative electrode side DC bus of the lighting device 8 via the negative electrode side connection terminal 100b. NS.

The lighting device 8 includes an input filter 2, a rectifier circuit 3 connected to the input filter 2, a capacitor 4 connected in parallel to the rectifier circuit 3, a PFC circuit 5, a smoothing capacitor 6 connected in parallel with the output of the PFC circuit 5. A current control circuit 7 is provided.

The lighting device 8 has a function of suppressing harmonics of the current input from the system voltage 1a to improve the power factor, and converting the power output from the rectifier circuit 3 into DC power and supplying it to the light source 100. .. The lighting device 8 outputs to a PFC circuit 5 for suppressing harmonics of a current input from the system voltage 1a to improve the power factor, a smoothing capacitor 6 for smoothing the output voltage of the PFC circuit 5, and a light source 100. It is provided with a current control circuit 7 that controls the magnitude of the current to be generated.

The transformer 1b has one grounded first terminal and two output terminals. These two output terminals are connected to the lighting device 8. The input filter 2 arranged between the system voltage 1a and the rectifier circuit 3 has a coil 2a and a capacitor 2b, and reduces a high frequency component superimposed on the current output from the system voltage 1a. The coil 2a is connected in series to the secondary side of the transformer 1b. One of the coils 2a is connected to the secondary side of the transformer 1b and the capacitor 2b, and the other of the coils 2a is connected to the rectifier circuit 3. The capacitor 2b is connected to the transformer 1b and the coil 2a.

The rectifier circuit 3 is arranged between the input filter 2 and the PFC circuit 5, and converts the AC power supplied from the system voltage 1a into DC power. The rectifier circuit 3 is composed of a diode bridge in which four diodes are combined. The configuration of the rectifier circuit 3 is not limited to this, and may be configured by combining MOSFETs that are unidirectional conductive elements.

The capacitor 4 is connected in parallel to the output of the rectifier circuit 3 and smoothes the output voltage of the rectifier circuit 3. One end of the capacitor 4 is connected to the positive electrode side DC bus, and the other end of the capacitor 4 is connected to the negative electrode side DC bus.

The PFC circuit 5 is arranged between the rectifier circuit 3 and the current control circuit 7. The PFC circuit 5 includes a MOSFET 5b which is a switching element, a coil 5a, and a diode 5c. By controlling the MOSFET 5b on and off by a control means (not shown), the PFC circuit 5 boosts the output voltage of the rectifier circuit 3 and outputs the boosted voltage to the smoothing capacitor 6. Further, the PFC circuit 5 has a function of suppressing harmonics of the input current and improving the power factor. Here, an example in which the PFC circuit 5 is configured by a step-up chopper circuit is shown. In addition to the step-up chopper circuit, a buck-boost chopper circuit, a flyback circuit, a flyforward circuit, a SEPIC (Single Ended Primary Inductor Converter), and a Zeta converter are shown. Alternatively, it may be configured by a circuit such as a Cuk converter.

The coil 5a is arranged between the capacitor 4 and the MOSFET 5b on the positive electrode side DC bus. The coil 5a is formed by winding an insulating wire around the core. One end of the coil 5a is connected to one end of the capacitor 4. The other end of the coil 5a is connected to the anode of the diode 5c. A voltage having a different polarity is applied to the coil 5a as the MOSFET 5b is turned on and off.

The drain of the MOSFET 5b is connected to the coil 5a and the anode of the diode 5c in the positive electrode side DC bus. The source of the MOSFET 5b is connected to the other end of the capacitor 4 and the other end of the smoothing capacitor 6 on the negative electrode side DC bus. A control signal for controlling the on / off state is input to the gate of the MOSFET 5b from a control means (not shown). On / off control of the MOSFET 5b is performed by inputting a control signal.

The diode 5c is arranged between the MOSFET 5b and the smoothing capacitor 6 on the positive electrode side DC bus. The anode of the diode 5c is connected to the coil 5a and the MOSFET 5b, and the cathode of the diode 5c is connected to the smoothing capacitor 6.

The smoothing capacitor 6 is arranged between the PFC circuit 5 and the current control circuit 7. One end of the smoothing capacitor 6 is connected to the positive electrode side DC bus, and the other end of the smoothing capacitor 6 is connected to the negative electrode side DC bus.

Next, the configuration and operation of the current control circuit 7 will be described.

The current control circuit 7 is composed of a MOSFET 7b, a coil 7a, a diode 7c, and a filter capacitor 7d. The MOSFET 7b is arranged on the positive electrode side DC bus. The drain of the MOSFET 7b is connected to one end of the smoothing capacitor 6 and the cathode of the diode 5c. The source of the MOSFET 7b is connected to the cathode of the diode 7c and one end of the coil 7a. A control signal is input to the gate of the MOSFET 7b from a control means (not shown). The control signal is a signal for on / off control of the MOSFET 7b.

One end of the coil 7a is connected to the source of the MOSFET 7b and the cathode of the diode 7c. The other end of the coil 7a is connected to one end of the filter capacitor 7d and one end of the light source 100. The cathode of the diode 7c is connected to the source of the MOSFET 7b and one end of the coil 7a. The anode of the diode 7c is connected to the other end of the smoothing capacitor 6, the other end of the filter capacitor 7d, and the other end of the light source 100.

In the example of FIG. 1, the current control circuit 7 is composed of a step-down chopper circuit. It may be composed of such a circuit.

The materials of the MOSFETs 5b and 7b, which are switching elements, are, for example, silicon-based semiconductors. According to another example, a wide bandgap semiconductor such as silicon carbide or gallium nitride based material can be used.

By using a wide bandgap semiconductor for the switching element, it is possible to reduce the energization loss of the switching element, and even if the switching frequency, that is, the drive frequency is set to a high frequency, heat dissipation is good. Therefore, the heat radiating components of the PFC circuit 5 and the current control circuit 7 can be miniaturized or omitted, and the lighting device 8 can be miniaturized and the cost can be reduced.

FIG. 3 is an external perspective view showing the configuration of the light source 100. The light source 100 includes a positive electrode side connection terminal 100c, a negative electrode side connection terminal 100b, an insulating substrate 100d, LED chips 101a, 102a, 103a, 104a, 105a, 106a, 107a, 108a, LED wiring 111e, 112e, 113e, 114e, 115e, It includes 116e, 117e, 118e, and 119e. In the configuration diagram shown in FIG. 1, the LED chips 101a, 102a, 103a, 104a, 105a, 106a, 107a, and 108a are simplified and shown as the LED group 100a. Here, the number of LED chips is eight, but the number of LED chips is designed according to the required magnitude of light output, and is not limited to eight. Further, the light source 100 may include a diffuser plate for diffusing the light output from the LED group 100a, but it is not shown because it has nothing to do with the phenomenon of slight lighting.

The light source 100 has a configuration mounted on the housing 10. Here, the housing 10 shows only a part of the lighting fixture 11, and is shown as a flat shape. In explaining the stray capacitance 120f shown in FIG. 1, which is a factor that causes slight lighting, it is not necessary to describe the entire housing 10, and an actual complicated shape such as drilling, bending, and drawing is shown. Since it is not necessary, only a part is shown as a flat shape.

The housing 10 supports the lighting device 8 and the light source 100, and makes it possible to attach the lighting fixture 11 to the ceiling, wall, or the like. For example, a steel plate is used as the material of the housing 10, and in this case, it also has a function of dissipating heat generated by the parts included in the lighting device 8 and the light source 100 and suppressing the temperature rise. In addition, the surface of the steel sheet may be painted or plated to enhance the design.

The negative electrode side connection terminal 100b is connected to the cathode terminal of the LED chip 101a via the LED wiring 111e. Further, it is electrically connected to the negative electrode side DC bus of the lighting device 8 via a harness or the like. In particular, when the LED group 100a and the lighting device 8 are mounted on the same substrate, the cathode terminal of the LED chip 101a and the negative electrode side DC bus of the lighting device 8 are electrically wired or copper without using the negative electrode side connection terminal 100b. It may be directly connected by a foil pattern.

The positive electrode side connection terminal 100c is connected to the anode terminal of the LED chip 108a via the LED wiring 119e. Further, it is electrically connected to the positive electrode side DC bus of the lighting device 8 via a harness or the like. In particular, when the LED group 100a and the lighting device 8 are mounted on the same substrate, the anode terminal of the LED chip 108a and the positive electrode side DC bus of the lighting device 8 are electrically wired or copper without using the positive electrode side connection terminal 100c. It may be directly connected by a foil pattern.

The LED chips 101a, 102a, 103a, 104a, 105a, 106a, 107a, 108a convert the current input from the lighting device 8 into light and output it. Here, the configuration in which the LED chips 101a, 102a, 103a, 104a, 105a, 106a, 107a, 108a are connected in series by the LED wirings 112e, 113e, 114e, 115e, 116e, 117e, 118e is shown. The connection method may be parallel or a combination of series and parallel.

The LED wirings 111e, 112e, 113e, 114e, 115e, 116e, 117e, 118e, 119e electrically connect the LED group 100a and the negative electrode side connection terminal 100b, and electrically connect the LED group 100a and the positive electrode side connection terminal 100c. The LED chips 101a, 102a, 103a, 104a, 105a, 106a, 107a, and 108a are electrically connected, respectively.

Specifically, the LED wiring 111e electrically connects the negative electrode side connection terminal 100b and the cathode of the LED chip 101a. Further, the LED wiring 119e electrically connects the positive electrode side connection terminal 100c and the anode of the LED chip 108a. The LED wiring 112e electrically connects the anode of the LED chip 101a and the cathode of the LED chip 102a. Similarly, the LED wiring 113e electrically connects the anode of the LED chip 102a and the cathode of the LED chip 103a. The LED wiring 114e electrically connects the anode of the LED chip 103a and the cathode of the LED chip 104a. The LED wiring 115e electrically connects the anode of the LED chip 104a and the cathode of the LED chip 105a. The LED wiring 116e electrically connects the anode of the LED chip 105a and the cathode of the LED chip 106a. The LED wiring 117e electrically connects the anode of the LED chip 106a and the cathode of the LED chip 107a. The LED wiring 118e electrically connects the anode of the LED chip 107a and the cathode of the LED chip 108a.

According to one example, in FIG. 3, the LED wirings 111e, 112e, 113e, 114e, 115e, 116e, 117e, 118e, 119e are formed by a copper foil pattern and adhered to one side of the insulating substrate 100d.

The other surface of the insulating substrate 100d is in contact with the housing 10 and is held by the housing 10. As a means for holding, an adhesive such as a silicone adhesive can be used. Alternatively, screwing or crimping with a clip can be used. At this time, in order to dissipate the heat generated by the LED chips 101a, 102a, 103a, 104a, 105a, 106a, 107a, 108a to the housing 10, a silicone resin is placed between the other surface of the insulating substrate 100d and the housing 10. It may be provided.

As the material of the insulating substrate 100d, a printed circuit board using an epoxy resin such as FR-4 or CEM-3 or a printed circuit board using a phenol resin such as FR-1 can be used.

FIG. 4 is a cross-sectional view of the light source 100, in which only the negative electrode side connection terminals 100b, the LED chips 101a, 102a, 103a, and the LED wirings 111e, 112e, 113e, and 114e are extracted. Since the housing 10 is a conductor when a steel plate is used, stray capacitances 121f, 122f, 123f, and 124f are formed between the housing 10 and the LED wirings 111e, 112e, 113e, and 114e, respectively. Although not shown, stray capacitances 125f, 126f, 127f, 128f, and 129f are also formed between the LED wirings 115e, 116e, 117e, 118e, 119e and the housing 10, respectively. In FIG. 1, stray capacitances 121f, 122f, 123f, 124f, 125f, 126f, 127f, 128f, and 129f are collectively described as 120f.

FIG. 1 shows a cause of a phenomenon in which the light source 100 is slightly turned on (hereinafter, may be referred to as slight lighting) even though the current control circuit 7 is stopped and the light source 100 is turned off. It will be described using.

Regarding the connection between the transformer 1b and the luminaire 11, the secondary side of the transformer 1b is a first terminal which is a grounded intermediate potential output terminal and two output terminals having a voltage of 100 Vrms with respect to the intermediate potential. It has. The output terminals of these three potentials are connected to the luminaire, and the two output terminals having a voltage of 100 Vrms are connected to the input filter 2. Further, the grounded intermediate potential first terminal is connected to the housing 10. The first terminal of the grounded intermediate potential and the input filter 2 may be connected via a capacitor, but this is not described because it is not related to the cause of slight lighting.

In FIG. 1, only the luminaire 11 is connected to the transformer 1b, but other luminaires may be connected in parallel depending on the usage conditions of the luminaire 11. In this case, a noise voltage may be generated at the grounded intermediate potential due to the operation of other devices connected in parallel. In particular, when another device connected in parallel is a device that involves a switching operation of a semiconductor switch, the noise voltage becomes a high-frequency AC voltage of several k to several 100 kHz.

When an AC noise voltage of several k to several 100 kHz is generated, the operation of the current control circuit 7 is stopped, and even when the light source 100 is turned off, a current may be generated in the lighting device.

FIG. 2 is a diagram showing a specific current path at the time of slight lighting. In the lighting device 8, it passes through the coil 2a of the input filter 2, branches in the rectifying circuit 3, joins the DC bus on the negative electrode side of the lighting device via the capacitor 4, branches at the filter capacitor 7d, and the light source 100. In, the path is input from the negative electrode side connection terminal 100b and the positive electrode side connection terminal 100c, passes through the LED group 100a, passes through the stray capacitance 120f, and passes through the housing 10. This route is indicated by an arrow. Since the stray capacitance 120f is formed in the light source 100, the operation of the current control circuit 7 is stopped when an AC noise voltage is generated, and a current path is formed even when the light source 100 is turned off. An electric current is generated in the lighting device. Then, since the LED group 100a is included in the current path, the LED group 100a is slightly lit, and slight lighting is generated.

The above-mentioned current path exists even when the current control circuit 7 is operating, that is, when the light source 100 is lit. Specifically, it is a phenomenon in which the light output by the light source 100 flickers when the current of the light source 100 is made lower than the rated output and the light is dimmed.

Next, conventional measures against slight lighting will be described.

FIG. 5 is a perspective view of the light source 200 according to the comparative example. Capacitors 131g, 132g, 133g, 134g, 135g, 136g, 137g, and 138g are connected in parallel with the LED chips 101a, 102a, 103a, 104a, 105a, 106a, 107a, and 108a, respectively. The parts having the same configuration as the light source 100 are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 6 is a configuration diagram of a lighting device 12 using the light source 200 according to the comparative example. Instead of the light source 100 of the lighting fixture 11 shown in FIG. 1, a light source 200 is provided. In FIG. 6, the capacitors 131 g, 132 g, 133 g, 134 g, 135 g, 136 g, 137 g, and 138 g of FIG. 5 are abbreviated as the capacitors 130 g.

The arrow in FIG. 6 indicates the current path when a noise voltage is generated at the grounded intermediate potential. As a specific current path, in the lighting device 8, the lighting device 8 passes through the coil 2a of the input filter 2, branches in the rectifier circuit 3, joins the negative electrode side DC bus of the lighting device via the capacitor 4, and filters. It is branched by the capacitor 7d, and is the same as the above-mentioned current path in the lighting device 8.

The current path in the light source 200 is input from the negative electrode side connection terminal 100b and the positive electrode side connection terminal 100c, passes through the capacitor 130g connected in parallel with the LED group 100a, passes through the stray capacitance 120f, and passes through the housing 10. It is a route to do.

In the light source 200, since the capacitor 130g is connected in parallel with the LED group 100a, even if the stray capacitance 120f is formed, the current due to the AC noise voltage easily flows through the capacitor 130g, so that it flows through the LED group 100a. Can be suppressed. As a result, it is possible to suppress the occurrence of slight lighting.

In FIG. 5, capacitors 131 g, 132 g, 133 g, 134 g, 135 g, 136 g, 137 g, and 138 g are connected in parallel to each of the LED chips 101a, 102a, 103a, 104a, 105a, 106a, 107a, and 108a. However, the present invention is not limited to this, and the same effect can be obtained by connecting capacitors in parallel to, for example, a series structure of two LED chips. In this case, since the number of capacitors used can be reduced, the number of parts can be reduced.

When the capacitor 130g is connected in parallel with the LED group 100a, a space for mounting the capacitor is required, so that the area of the insulating substrate 100d in the light source 200 becomes large. Therefore, in addition to the increase in the number of parts, there is a problem that the cost increases due to the increase in the substrate area.

Further, even if a capacitor 130g is connected in parallel with the LED group 100a, it is not possible to completely prevent the current from flowing to the LED. Therefore, as the noise voltage increases, the current increases and slight lighting may occur. There is sex.

FIG. 7 is a perspective view showing the configuration of the light source 300 according to the first embodiment of the present disclosure. Parts having the same or corresponding configurations as those described above are designated by the same reference numerals, and the description thereof will be omitted.

The differences from the comparative example of the light source 300 are that it is provided with the back surface wiring 100e, that it is provided with the through wiring 100j that electrically connects the LED wiring 111e and the back surface wiring 100e, and that it is provided with the insulating layer 100h. Is.

In FIG. 7, the other surface of the insulating substrate 100d, that is, the surface including the LED chips 101a, 102a, 103a, 104a, 105a, 106a, 107a, 108a, LED wiring 112e, 113e, 114e, 115e, 116e, 117e, 118e. The back surface wiring 100e is provided on the opposite side.

The back surface wiring 100e is, for example, a copper pattern adhered to the insulating substrate 100d. Further, the back surface wiring 100e and the LED wiring 111e are electrically connected. As a connection method, there is a method in which a through hole is provided in the insulating substrate 10d, a through wiring 100j is provided in the through hole, and the back surface wiring 100e and the LED wiring 111e are connected by the through wiring 100j. As will be described later, the back surface wiring 100e may be connected to the LED wiring 119e.

An insulating layer 100h is provided on the housing 10 of the conductor. The insulating layer 100h is provided between the back surface wiring 100e and the housing 10, and insulates the back surface wiring 100e and the housing 10. As the material of the insulating layer, an insulating film such as polyester or polyimide can be used. By using the insulating layer 100h which is a thin film and has a low thermal resistance, it is possible to suppress the influence of preventing the heat generated in the LED group 100a from being transferred to the housing 10.

FIG. 8 is an exploded perspective view showing the configuration of the light source 300. When the longitudinal direction of the light source 300 is the length and the lateral direction is the width, the length of the back surface wiring 100e is A'and the width is A. Further, the length of the insulating layer 100h is B'and the width is B.

Since it is necessary to electrically insulate the back surface wiring 100e from the housing 10, the length B'of the insulating layer 100h is made longer than the length A'of the back surface wiring 100e. Further, the length B of the insulating layer 100h is made longer than the length A of the back surface wiring 100e. As a result, the insulating layer 100h is larger than the back surface wiring 100e in a plan view, and the entire back surface of the back surface wiring 100e is in contact with the insulating layer 100h.

FIG. 9 is a cross-sectional view of the light source 300 extracted from the negative side connection terminal 100b, the LED chips 101a, 102a, 103a, the LED wirings 111e, 112e, 113e, 114e, the through wiring 100j, and the like. Stray capacitances 122f', 123f', and 124f'are generated between the back surface wiring 100e and the LED wirings 112e, 113e, and 114e, respectively. Although not shown, stray capacitances 125f', 126f', 127f', 128f', and 129f' are generated between the LED wirings 115e, 116e, 117e, 118e, 119e and the housing 10, respectively. In FIG. 9, a back surface wiring 100e provided on the insulating layer 100h, an insulating substrate 100d provided on the back surface wiring 100e and having a through hole formed therein, and a plurality of LEDs provided on the insulating substrate 100d are shown. LED wirings 111e, 112e, 113e, 114e that are connected to form a circuit are shown. The insulating substrate 100d, the backside wiring 100e, and all the LED wiring can be provided as part of the double-sided printed circuit board.

FIG. 10 is a circuit diagram of a lighting fixture that employs the light source 300. The same or corresponding parts as those described above are designated by the same reference numerals, and the description thereof will be omitted. In FIG. 10, stray capacitances 122f', 123f', 124f', 125f', 126f', 127f', 128f', and 129f' are collectively referred to as stray capacitance 120f'. When a conductor such as a steel plate is used as the housing 10, a stray capacitance is formed between the housing 10 and the back surface wiring 100e. In particular, the stray capacitance formed between the housing 10 and the back surface wiring 100e is called a bypass capacitor 100k.

The configuration of FIG. 10 is different from the configurations of FIGS. 1 and 6 in that the light source 300 is provided. The arrow in FIG. 10 indicates the current path when a noise voltage is generated at the grounded intermediate potential. As a specific current path, in the lighting device 8, the lighting device 8 passes through the coil 2a of the input filter 2, branches in the rectifier circuit 3, and joins the negative electrode side DC bus of the lighting device via the capacitor 4. Is.

In the light source 300, the negative electrode side connection terminal 100b and one end of the bypass capacitor 100k are electrically connected by a through wiring 100j. Therefore, since the impedance between the negative electrode side connection terminal 100b and one end of the bypass capacitor 100k is sufficiently low, the current flowing through the LED group 100a and the stray capacitance 120f'is suppressed.

As a result, the current path is a path that passes through the housing 10 from the negative electrode side DC bus of the lighting device via the negative electrode side connection terminal 100b and the bypass capacitor 100k.

In the present embodiment, as described above, the negative electrode side connection terminal 100b and one end of the bypass capacitor 100k are electrically connected by the through wiring 100j, and between the negative electrode side connection terminal 100b and one end of the bypass capacitor 100k. Since the impedance of the LED group is sufficiently low, the current flowing through the LED group 100a and the floating capacitor 120f'is suppressed, so that the occurrence of slight lighting can be suppressed.

Here, the portion of the LED wiring that becomes the input end or the output end of the circuit is referred to as an "LED wiring end portion". For example, a connection terminal is connected to an LED wiring end portion that is an input end of a circuit and an LED wiring end portion that is an output end of a circuit. In the example of FIG. 7, the LED wirings 111e and 119e are the LED wiring end portions. The through wiring electrically connects such an LED wiring end portion and the back surface wiring 100e. Therefore, in the example of FIG. 7, the penetrating wiring 100j is connected to the LED wiring 111e, but the LED wiring 119e and the back surface wiring 100e may be connected by the penetrating wiring. In this case, one end of the positive electrode side connection terminal 100c and the bypass capacitor 100k is electrically connected by the through wiring 100j. Therefore, the impedance between the positive electrode side connection terminal 100c and one end of the bypass capacitor 100k becomes sufficiently low, and the current flowing through the LED group 100a and the stray capacitance 120f'is suppressed.

As a result, the current path becomes a path from the negative side DC bus of the lighting device to the filter capacitor 7d, the positive side connection terminal 100c, and the bypass capacitor 100k, and passes through the housing 10, and the filter capacitor 7d and the positive side are connected. Since the impedance between the terminal 100c and one end of the bypass capacitor 100k is sufficiently low, the current flowing through the LED group 100a and the floating capacitance 120f'is suppressed, so that the occurrence of slight lighting can be suppressed.

In the configuration of FIG. 7-10 according to the present embodiment, the capacitors 131 g, 132 g, 133 g, 134 g, 135 g, 136 g, 137 g, and 138 g shown in FIG. 5 are unnecessary, so that the number of parts can be reduced and the number of parts can be reduced. , The area of the insulating substrate 100d can be reduced.

Embodiment 2.
FIG. 11 is a perspective view showing the configuration of the light source 400 according to the second embodiment. The same or corresponding parts as those described in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 12 is an exploded perspective view of the light source 400 of FIG. The back surface wiring 101e is, for example, a copper pattern and is adhered to the insulating substrate 100d. Further, the back surface wiring 101e and the LED wiring 111e are electrically connected by the through wiring 100j. As in the configuration 1 of the implementation, the back surface wiring 101e and the LED wiring 119e may be connected to each other.

The insulating layer 101h is provided between the back surface wiring 101e and the housing 10, and insulates the back surface wiring 101e and the housing 10. As the material of the insulating layer 101h, an insulating film such as polyester or polyimide can be used. By using an insulating layer which is a thin film and has a low thermal resistance, it is possible to suppress the influence of preventing the heat generated in the LED group 100a from being transferred to the housing 10.

When the longitudinal direction of the light source 400 is the length and the other direction is the width, the length of the back surface wiring 101e is C'and the width is C. Further, the length of the insulating layer 101h is D'and the width is D.

Since it is necessary to electrically insulate the back surface wiring 101e from the housing 10, the length D'of the insulating layer 101h is made longer than the length C'of the back surface wiring 101e. Further, the length D of the insulating layer 101h is made longer than the length C of the back surface wiring 101e.

Since the principle that the slight lighting is suppressed by the configuration of the second embodiment is the same as that of the first embodiment, a detailed description will not be described.

In the second embodiment, the back surface wiring 101e includes the LED chips 101a, 102a, 103a, 104a, 105a, 106a, 107a, 108a, and the LED wirings 111e, 112e, 113e, 114e, 115e, 116e, 117e, 118e, The shape is substantially the same as the projected shape of 119e. That is, the back surface wiring 101e has substantially the same projection shape as the structure including the plurality of LEDs and the LED wiring. As a result, while suppressing the formation of stray capacitances 122f, 123f, 124f, 125f, 126f, 127f, 128f between the housing 10 and the LED wirings 112e, 113e, 114e, 115e, 116e, 117e, 118e. , A bypass capacitor 100k is formed. Since the back surface wiring 101e has a smaller area than the back surface wiring 100e of the first embodiment, the capacity of the bypass capacitor 100k can be reduced.

When the capacity of the bypass capacitor 100k is large, the leakage current leaking from the lighting device 8 to the transformer 1b side increases. However, according to the second embodiment, by providing the bypass capacitor 100k, it is possible to suppress the increase in the leakage current while suppressing the slight lighting as described above.

In the second embodiment, the back surface wiring 101e has substantially the same shape as the projected shape of all the LED chips and all the LED wirings, but the shape is not limited to this. For example, by making the shape of the back surface wiring including all the LED chips and the projected shapes of all the LED wirings, it is possible to suppress the slight lighting and the effect of suppressing the increase in the leakage current.

Embodiment 3.
FIG. 13 is a perspective view showing the configuration of the light source 500 according to the third embodiment. Parts having the same or corresponding configurations as those described above are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 13, a plurality of LED chips and LED wirings 111e', 112e', 113e', 114e', 115e', 116e', 117e', 118e', 119e' connecting the plurality of LED chips are placed on the insulating substrate 100d. Is provided. LED wirings 111e'and 119e' are provided as LED wiring end portions corresponding to the end portions of the circuit. The LED wiring 119e'is a first LED wiring which is an input end of the circuit. The LED wiring 111e'is a second LED wiring which is an output end of the circuit. The first LED wiring and the second LED wiring are adjacent to each other. In this example, the LED wiring 111e', which is the second LED wiring, is provided with the through wiring, but one or both of the first LED wiring and the second LED wiring can be provided with the through wiring.

FIG. 14 is an exploded perspective view of the light source of FIG. A back surface wiring 102e is provided on the back surface side of the insulating substrate 100d. The back surface wiring 102e is, for example, a copper pattern and is adhered to the insulating substrate 100d. The back surface wiring 102e is electrically connected to the LED wiring 111e'by a through wiring. The back surface wiring and the LED wiring 119e'can also be connected by a through wiring.

The insulating layer 102h is provided between the back surface wiring 102e and the housing 10, and insulates the back surface wiring 102e and the housing 10. As the material of the insulating layer, an insulating film such as polyester or polyimide can be used. By using an insulating layer which is a thin film and has a low thermal resistance, it is possible to suppress the influence of preventing the heat generated in the LED group 100a from being transferred to the housing 10.

As shown in FIG. 14, when the longitudinal direction of the light source 500 is the length and the other direction is the width, the length of the back surface wiring 102e is E'and the width is E. Further, the length of the insulating layer 102h is F'and the width is F.

Since it is necessary to electrically insulate the back surface wiring 102e from the housing 10, the length F'of the insulating layer 102h is made longer than the length E'of the back surface wiring 102e. Further, the width F of the insulating layer 102h is made longer than the width E of the back surface wiring 102e.

Since the principle that the slight lighting is suppressed by the configuration of the third embodiment is the same as that described in the first embodiment, a detailed description will not be described.

Since the back surface wiring 102e has the above-described configuration, the back surface wiring 102e has substantially the same shape as the projected shapes of the LED chips 101a and 108a and the LED wirings 111e'and 119e'. In other words, the back surface wiring 102e has substantially the same projection shape as the portion including the first LED wiring, the second LED wiring, and the region between the first LED wiring and the second LED wiring.

Since the noise current flowing through the stray capacitance 120f is concentrated on the LED chips 101a and 108a, slight lighting is most likely to occur. Therefore, among the mounting patterns of the LED group 100a, the LED chips 101a and 108a are integrated in one direction in the longitudinal direction of the light source 500, and the LED chips 101a and 108a and the LED wirings 111e' and 119e provided as the LED wiring ends are provided. It was decided to provide the back surface wiring 102e having substantially the same shape as the projected shape of ′. As a result, the area of the back surface wiring 102e can be reduced while suppressing the slight lighting of the LED.

Since the back surface wiring 102e has a smaller area than the back surface wiring 100e of the first embodiment, the capacity of the bypass capacitor 100k can be reduced.

When the capacity of the bypass capacitor 100k is large, the leakage current leaking from the lighting device 8 to the transformer 1b side increases. According to the third embodiment, by providing the bypass capacitor 100k, it is possible to suppress an increase in leakage current while suppressing slight lighting.

Further, since the area of the back surface wiring 102e is small, the area of the insulating layer 102h can also be reduced, which is suitable for cost reduction. Further, the metal body can be provided in the portion of the region between the insulating substrate 100d and the housing 10 where the back surface wiring 102e and the insulating layer 102h are not provided. Since the back surface wiring 102e has a small area, the area where the insulating substrate 100d and the housing 10 come into contact with each other via the metal body can be increased. Therefore, the heat dissipation of the LED group 100a can be improved.

In the third embodiment, the back surface wiring 102e has substantially the same shape as the projected shapes of the LED chips 101a and 108a and the LED wirings 111e'and 119e', but the shape is not limited to this. The size of the back surface wiring 102e can be adjusted according to the ease of occurrence of slight lighting. For example, the back surface wiring 102e can have substantially the same shape as the projected shapes of the LED chips 101a, 102a, 107a, 108a and the LED wirings 111e', 112e', 118e', and 119e'. According to another example, it can be substantially the same as another projected shape. In this way, it is possible to obtain the effect of selectively suppressing the slight lighting, suppressing the increase in the leakage current and the cost of the insulating layer 102h, and improving the heat dissipation of the LED group 100a.

The configuration shown in the above-described embodiment shows an example of the contents of the present disclosure, and the configurations 1, 2 and 3 of the embodiment can be combined with each other, or can be combined with another known technique. It is possible to omit or change a part of the configuration without departing from the gist of the present disclosure.

Further, although the case where the light source includes the LED chip has been described, the light source is not limited to the LED chip and may be an organic EL (Electro Luminescence).

1a system voltage, 1b transformer, 1c ground potential, 2 input filter, 2a coil, 2b capacitor, 3 rectifier circuit, 4 capacitor, 5 PFC circuit, 5a coil, 5b MOSFET, 5c diode, 6 smoothing capacitor, 7 current control circuit , 7a coil, 7b MOSFET, 7c diode, 8 lighting device, 10 housing, 11, 12, 13 lighting equipment, 100 light source, 100a LED group, 100b negative side connection terminal, 100c positive side connection terminal, 100d insulation substrate, 101a , 102a, 103a, 104a, 105a, 106a, 107a, 108a LED chips, 100e, 101e, 102e Backside wiring, 111e, 112e, 113e, 114e, 115e, 116e, 117e, 118e, 119e, 111e', 112e', 113e ′, 114e ′, 115e ′, 116e ′, 117e ′, 118e ′, 119e ′ LED wiring, 120f, 121f, 122f, 123f, 124f, 125f, 126f, 127f, 128f, 129f, 120f ′, 122f ′, 123f ′ , 124f', 125f', 126f', 127f', 128f', 129f'Floating capacity, 100h, 101h, 102h Insulation layer, 100j through wiring, 100k bypass capacity

Claims (8)

Conductor housing and
An insulating layer provided on the housing and
The back surface wiring provided on the insulating layer and
An insulating substrate provided on the back surface wiring and having through holes formed therein.
A plurality of LED chips provided on the insulating substrate and
An LED wiring provided on the insulating substrate and connecting the plurality of LED chips to form a circuit,
A light source provided in the through hole and provided with an LED wiring end portion of the LED wiring which is an input end or an output end of the circuit and a through wiring for electrically connecting the back surface wiring. The light source according to claim 1, wherein the insulating substrate, the back surface wiring, and the LED wiring are provided as a part of the double-sided printed circuit board. The light source according to claim 1 or 2, wherein the insulating layer is larger than the back surface wiring in a plan view, and the entire back surface of the back surface wiring is in contact with the insulating layer. The light source according to any one of claims 1 to 3, further comprising a connection terminal connected to the end of the LED wiring. The light source according to any one of claims 1 to 4, wherein the back surface wiring has a projection shape substantially the same as the structure including the plurality of LED chips and the LED wiring. The LED wiring end portion has a first LED wiring which is an input end of the circuit and a second LED wiring which is an output end of the circuit.
The first LED wiring and the second LED wiring are adjacent to each other.
Claim 1 is characterized in that the back surface wiring has substantially the same projection shape as a portion including the first LED wiring, the second LED wiring, and the region between the first LED wiring and the second LED wiring. 4. The light source according to any one of 4. The light source according to claim 6, wherein the plurality of LED chips are connected in series. The light source according to any one of claims 1 to 7.
A lighting device electrically connected to the input end and the output end,
A luminaire comprising a transformer having one grounded first terminal and two output terminals, the two output terminals being connected to the lighting device.

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