JP5685104B2 - Lighting device and lighting apparatus provided with the same - Google Patents

Description

  The present invention relates to a lighting device for lighting a light emitting element and a lighting fixture including the same.

  2. Description of the Related Art Conventionally, lighting devices that light a light emitting element by applying a DC voltage to the light emitting element such as an organic EL (ElectroLuminescence) or LED (Light Emitting Diode) have been provided. This type of lighting device includes a lighting device having a power supply circuit (DC power supply means) that outputs a desired DC voltage, and a switching element inserted between the power supply circuit and a light emitting element (organic EL element). Yes (see, for example, Patent Document 1). The lighting device described in Patent Document 1 is configured to change the light output of the light emitting element by variably controlling the duty ratio of the switching element.

  However, in a lighting device that lights a light emitting element made of organic EL, for example, since the organic EL is a capacitive element, a surge current flows due to the capacitance component of the light emitting element when the output of the power supply circuit is turned on or off. There is. On the other hand, it is considered that the rise or fall of the current in the EL element part is alleviated by inserting a coil or a resistor between the DC power source and the EL element part (see, for example, Patent Document 2). .

JP 2007-265805 A Japanese Patent No. 4359959

  However, even with the configuration as described above, if some surge current components remain, surge current may become a problem when a plurality of light emitting elements are turned on simultaneously. That is, when a plurality of light emitting elements are connected in parallel to the lighting device, when the output of the power supply circuit is simultaneously turned on or off with respect to the plurality of light emitting elements, a surge current is simultaneously generated in the plurality of light emitting elements, Stress and noise applied to the power supply circuit increase.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide a lighting device that can reduce stress and noise applied to a power supply circuit and a lighting fixture including the same.

A lighting device of the present invention includes a power supply circuit that applies a voltage to a plurality of light emitting units that have light emitting elements and are connected in parallel, and that have the same characteristics, and between the power supply circuit and the plurality of light emitting units. An impedance element to be inserted is provided for each light emitting unit, and includes a surge reduction circuit that determines a time constant of a series circuit of the impedance element and the light emitting unit according to an impedance value of the impedance element, the surge reduction circuit, It has at least two types of impedance elements having different impedance values.

  In this lighting device, the impedance element is preferably an inductor.

  The lighting device includes a switching element that is inserted between the power supply circuit and the light emitting unit and controls an output of the power supply circuit to the light emitting unit. The light output of the light emitting element is obtained by switching the switching element. It is more desirable to provide a dimming control unit for changing.

  In this lighting device, the light emitting element is more preferably an organic EL element.

  The lighting device includes an output control unit that controls an output of the power supply circuit applied to the light emitting unit, and the output control unit arranges timings for changing the output of the power supply circuit in the plurality of the light emitting units. It is more desirable.

  The lighting device includes an output control unit that controls an output of the power circuit applied to the light emitting unit, and the output control unit may change the output of the power circuit individually for each light emitting unit. desirable.

  In this lighting device, each light emitting unit individually has a switching element that is inserted between the power circuit and the light emitting unit and controls the output of the power circuit to the light emitting unit, and the output control unit includes: It is more desirable to switch the plurality of switching elements at different periods for each light emitting unit.

  The lighting fixture of this invention is equipped with one of the said lighting devices and the fixture main body provided with the said light emitting element, It is characterized by the above-mentioned.

  The present invention has an advantage that stress and noise applied to the power supply circuit can be reduced because the surge reduction circuit has at least two types of impedance elements having different impedance values.

1 is a schematic circuit diagram illustrating a configuration of a lighting device according to Embodiment 1. FIG. 1 is an exploded perspective view illustrating a configuration of a lighting fixture according to Embodiment 1. FIG. It is explanatory drawing which shows operation | movement of a comparative example. FIG. 6 is an explanatory diagram illustrating an operation of the lighting device according to the first embodiment. FIG. 6 is a schematic circuit diagram illustrating another configuration of the lighting device according to the first embodiment. FIG. 6 is a schematic circuit diagram illustrating still another configuration of the lighting device according to the first embodiment. 6 is a schematic circuit diagram illustrating a configuration of a lighting device according to Embodiment 2. FIG. It is the schematic which shows the structure of the lighting device which concerns on Embodiment 3. FIG.

(Embodiment 1)
As shown in FIG. 2, the lighting fixture 10 of the present embodiment applies a voltage to the panel-type fixture body 100 provided with a plurality of light emitting units 25 and 26 (see FIG. 1) and the light emitting units 25 and 26. And the lighting device 1 for lighting the light emitting units 25 and 26. In this luminaire 10, the light emitting sections 25 and 26 are planar light sources, and are arranged as four light emitting elements 21 to 24 arranged so as to be lined up vertically and horizontally (hereinafter referred to as “light emitting element 20” unless otherwise distinguished from each other). The lighting device 1 is electrically connected to all the light emitting elements 20. Thus, if the light emitting element 20 which consists of a planar light source is used, the lighting fixture 10 can be reduced in thickness, for example, the lighting fixture 10 suitable as indoor lighting can be implement | achieved.

  Hereinafter, a detailed configuration of the lighting device 1 will be described with reference to FIG.

  The lighting device 1 is inserted between the DC power supply circuit 3 that outputs a desired DC voltage and the DC power supply circuit 3 and the light emitting units 25 and 26, and controls the output of the DC power supply circuit 3 to the light emitting units 25 and 26. A switching element 4 and a control unit 5 that controls the switching element 4 are provided. Further, the lighting device 1 has a surge reduction circuit 6 inserted between the positive-side output terminal of the DC power supply circuit 3 and the light emitting units 25 and 26. The surge reduction circuit 6 will be described later. In addition, the control part 5 is comprised as a main structure, for example with a microcomputer (microcomputer).

  Each light emitting element 20 constituting the light emitting units 25 and 26 is composed of an organic EL (ElectroLuminescence) panel which is a planar light source, and emits light when a DC voltage output from the DC power supply circuit 3 is applied. In the present embodiment, each of the light emitting elements 21 to 24 is composed of an organic EL panel of the same type and the same size.

  Here, the light emitting element 21 and the light emitting element 22 are connected in series to form the first light emitting unit 25, and the light emitting element 23 and the light emitting element 24 are connected in series to form the second light emitting unit 26. The light emitting units 25 and 26 are connected in parallel between the output terminals of the DC power supply circuit 3.

  The DC power supply circuit 3 is composed of a rectifier circuit 31 composed of a diode bridge and a converter 32. The AC voltage from the AC power supply 30 is full-wave rectified by the rectifier circuit 31, and the rectified pulsating voltage is supplied to the converter 32. Step down to a desired DC voltage. The converter 32 has a series circuit of a switch element 33 made of a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), an inductor 34, and a capacitor 35 between the output terminals of the rectifier circuit 31. The converter 32 further includes a diode 36 connected between both ends of the series circuit of the inductor 34 and the capacitor 35, and a drive circuit 37 that switches the switch element 33.

  The converter 32 controls the switch element 33 with a drive circuit 37, and performs PWM (Pulse Width Modulation) control for changing the duty ratio of the switch element 33, whereby a DC voltage of a desired magnitude is a capacitor serving as an output terminal. 35 is output from both ends. In the present embodiment, the drive circuit 37 performs PWM control so that a voltage having a magnitude necessary for lighting the light emitting element 20 is output from the converter 32.

  Note that the converter 32 is not limited to the step-down circuit as described above, and may be composed of, for example, a step-up circuit, a step-up / step-down chopper circuit, or the like, and may have a function as a PFC (Power Factor Correction) circuit. Further, instead of the converter 32, only a smoothing capacitor may be provided. In the case of a chopper circuit, the switch element 33 is switched at several tens kHz to several hundreds kHz.

  The switching element 4 is made of a MOSFET, and is inserted between the output terminal on the negative electrode side of the DC power supply circuit 3 and the light emitting units 25 and 26. The control unit 5 switches the on / off state of the switching element 4 alternately by giving a control signal to the switching element 4 so that the output voltage of the DC power supply circuit 3 is intermittently applied to the light emitting units 25 and 26. The element 4 is controlled. The switching element 4 and the control unit 5 constitute an output control unit 7 that controls the output of the DC power supply circuit 3 applied to the light emitting units 25 and 26. In the present embodiment, since the output control unit 7 has the switching element 4 common to both the first and second light emitting units 25 and 26, the timing for changing the output of the DC power supply circuit 3 is the first and second timings. Both light emitting sections 25 and 26 are aligned.

  Here, the lighting device 1 of the present embodiment can operate in a plurality of lighting modes including a dimming lighting mode in which the light output of the light emitting element 20 is changed by switching the switching element 4. In this case, the switching element 4 and the control unit 5 constitute a dimming control unit. In the dimming lighting mode, the control unit 5 applies a rectangular wave PWM signal to the switching element 4 to drive the switching element 4, and performs PWM control to change the duty ratio of the switching element 4, thereby performing light output of the light emitting element 20. To change. In the present embodiment, at least the lighting device 1 can switch between a dimming lighting mode in which the switching element 4 is intermittently turned on and a full lighting mode (DC lighting mode) in which the switching element 4 is continuously turned on. It is. These lighting modes are switched by the control unit 5 in accordance with an operation signal from a remote control device (not shown).

  Further, the control unit 5 determines the magnitude of the output voltage of the converter 32 (the voltage applied to the light emitting units 25 and 26 when the switching element 4 is turned on) according to the dimming rate, instead of the PWM control of the switching element 4. It may be changed. Alternatively, the control unit 5 may change the magnitude of the output voltage of the converter 32 in accordance with the dimming rate in addition to the PWM control of the switching element 4. That is, the control unit 5 may control the converter 32 so that the output voltage of the converter 32 becomes smaller as the dimming becomes deeper (the dimming rate becomes lower). In this case, the control unit 5 and the converter 32 constitute an output control unit 7 that controls the output of the DC power supply circuit 3 applied to the light emitting units 25 and 26.

  In FIG. 1, the surge reduction circuit 6 is in series with the first inductor 61 connected in series with the light emitting elements 21 and 22 of the first light emitting unit 25 and the light emitting elements 23 and 24 of the second light emitting unit 26. A second inductor 62 is connected. Each of the first and second inductors 61 and 62 functions as an impedance element that reduces a surge current. Thereby, the time constant of the series circuit of the first inductor 61 and the first light emitting unit 25 is determined by the inductance (impedance value) of the first inductor 61. Similarly, the time constant of the series circuit of the second inductor 62 and the second light emitting unit 26 is determined by the inductance (impedance value) of the second inductor 62.

  By the way, when the output of the DC power supply circuit 3 changes, that is, when the output of the DC power supply circuit 3 is turned on or off by the switching element 4 or when the magnitude of the output voltage of the converter 32 changes, the capacitance component of the light emitting element 20. Due to the surge current may flow. This surge current is reduced to some extent by the first and second inductors 61 and 62 that are impedance elements of the surge reduction circuit 6 alleviate the rise and fall of the current flowing through the light emitting element 20.

  Here, since the impedance elements for reducing the surge current are the inductors 61 and 62, the surge current component decreases as the inductance (impedance value) of the surge reduction circuit 6 increases. However, when the inductance of the surge reduction circuit 6 increases, the inductive component (L component) of the inductors 61 and 62 resonates with the capacitive component (C component) of the light emitting element (organic EL) 20 that is a capacitive element. The current waveform is greatly distorted or vibrated. Therefore, the optimum value of the inductance of the surge reduction circuit 6 is a value that can suppress the surge current to the smallest value within the range where these distortions and vibrations do not affect.

  However, although the surge current component is reduced to some extent by the surge reduction circuit 6, it is not completely eliminated as shown in FIG. 3. Therefore, in the conventional configuration, when a plurality of light emitting elements 20 are lit simultaneously. Surge current can be a problem. 3A shows a current waveform of the first light emitting unit 25, FIG. 3B shows a current waveform of the second light emitting unit 26, and FIG. 3C shows a current waveform of the DC power supply circuit 3. FIG. That is, when the outputs of the DC power supply circuit 3 to the first and second light emitting units 25 and 26 change at the same time, surge currents are generated at both the light emitting units 25 and 26 at the same time.

  Here, since the current I 0 flowing through the DC power supply circuit 3 is the sum of the current I 1 flowing through the first light emitting unit 25 and the current I 2 flowing through the second light emitting unit 26, the surge of both the light emitting units 25, 26. Due to the current, an excessive current I0 may flow through the DC power supply circuit 3 as shown in FIG. As a result, the stress applied to the DC power supply circuit 3 increases. Further, when the output of the DC power supply circuit 3 changes, surge currents are generated simultaneously in the plurality of light emitting elements 20, so that when the output of the DC power supply circuit 3 changes at a constant frequency, noise generated at the frequency is also generated. growing. If the impedance value of the surge reduction circuit 6 is increased, the surge current component is further reduced. However, in this case, another problem such as an increase in distortion of the current waveform, a delay in starting time, or an increase in the size of the impedance element occurs. .

  Therefore, the lighting device 1 of the present embodiment reduces the stress and noise applied to the DC power supply circuit 3 without causing problems such as an increase in current waveform distortion, a delay in starting time, or an increase in the size of the impedance element. The following configuration is adopted.

  That is, in the present embodiment, the surge reduction circuit 6 has at least two types of impedance elements (inductors) having different impedance values. Specifically, inductors 61 and 62 having different inductances (impedance values) are used as impedance elements of the surge reduction circuit 6 provided for each of the light emitting units 25 and 26 connected in parallel. In short, the first inductor 61 connected in series to the light emitting elements 21 and 22 of the first light emitting unit 25 and the second inductor 62 connected in series to the light emitting elements 23 and 24 of the second light emitting unit 26 are: Inductance is different. Here, the inductance of the second inductor 62 is larger than that of the first inductor 61.

  Thus, the time constant differs between the series circuit of the first inductor 61 and the first light emitting unit 25 and the series circuit of the second inductor 62 and the second light emitting unit 26. Therefore, the first light emitting unit 25 and the second light emitting unit 26 have different rates of change when the currents I1 and I2 rise and fall as shown in FIG. 4A shows the current waveform of the first light emitting unit 25, FIG. 4B shows the current waveform of the second light emitting unit 26, and FIG. 4C shows the current waveform of the DC power supply circuit 3. FIG.

  That is, since the inductance of the second inductor 62 is larger than that of the first inductor 61, the second light emitting unit 26 is associated with on / off of the switching element 4 rather than the first light emitting unit 25. The change in current becomes gradual. In other words, in the second light emitting unit 26, compared to the first light emitting unit 25, the current turn-on time and turn-off time when the switching element 4 is turned on / off are longer. Therefore, the time from when the switching element 4 is turned on to when the overshoot or undershoot occurs is longer in the second light emitting unit 26 than in the first light emitting unit 25, and the current I1 in both the light emitting units 25 and 26 is longer. , I2 has a variation in timing when it reaches a peak.

  As a result, the current waveform of the DC power supply circuit 3 becomes a waveform obtained by superimposing waveforms with shifted peak timings as shown in FIG. 4C, and the surge current component is dispersed in the time axis direction. The peak value of the current I0 flowing through the DC power supply circuit 3 can be kept small. Therefore, the stress applied to the DC power supply circuit 3 is reduced. In addition, since the generation period of the surge current of each light emitting element 20 is also distributed in the time axis direction, the frequency band in which noise is generated is also distributed, and the noise is reduced.

  As described above, according to the lighting device 1 of the present embodiment, the surge reduction circuit 6 includes the inductors 61 and 62 having different impedance values (inductances) for the light emitting units 25 and 26, so that the DC power supply circuit 3 is provided. Stress and noise can be reduced. In short, since the impedance value between the DC power supply circuit 3 and the light emitting units 25 and 26 is different for each light emitting unit 25 and 26, the series circuit of the first inductor 61 and the first light emitting unit 25, the second The time constant differs from the series circuit of the inductor 62 and the second light emitting unit 26. Therefore, the surge current component is automatically dispersed in the time axis direction.

  As a result, there is an effect that the stress and noise applied to the DC power supply circuit 3 can be reduced without causing problems such as an increase in distortion of the current waveform, a delay in starting time, or an increase in the size of the impedance element. By providing such a lighting device 1 in the lighting fixture 10, it becomes possible to provide the lighting fixture 10 with high reliability.

  Moreover, in the lighting device 1 of the present embodiment, since the timing of changing the output of the DC power supply circuit 3 is uniform in both the light emitting units 25 and 26, the surge current component is dispersed in the time axis direction, so the output control unit The configuration of 7 is simplified. That is, compared with the configuration in which the timing of the change in the output of the DC power supply circuit 3 is shifted between the light emitting units 25 and 26, in the present embodiment, a switching element is provided for each of the light emitting units 25 and 26, or the control unit 5 is complicated. The configuration of the output control unit 7 is simplified as much as it is not necessary to perform control. Further, in the present embodiment, the output control unit 7 can simultaneously control the output of the DC power supply circuit 3 to both the light emitting units 25 and 26, thereby shortening the time required for the light emitting units 25 and 26 to start and turn off and change the light output. can do.

  In addition, since the impedance element of the surge reduction circuit 6 is an inductor, the loss generated in the surge reduction circuit 6 can be reduced compared to the case where the impedance element is a resistor.

  Here, since the control unit 5 changes the light output of the light emitting element 20 by switching the switching element 4 in the dimming lighting mode, the voltage waveform of the light emitting element 20 or the DC power supply circuit 3 rises in the dimming lighting mode.・ Changes sharply at the fall. Therefore, a large surge current is likely to occur in the dimming lighting mode, and the effect that the stress and noise applied to the DC power supply circuit 3 are reduced by the surge reduction circuit 6 becomes remarkable. Further, since the light emitting element 20 is made of an organic EL that is a planar light source, the capacitance component is relatively large and a large surge current is likely to be generated. Therefore, the surge reduction circuit 6 reduces stress and noise applied to the DC power supply circuit 3. The effect becomes remarkable.

  By the way, as the impedance element of the surge reduction circuit 6, a resistor may be used instead of the inductor. In this case, the surge current component decreases as the resistance value (impedance) of the surge reduction circuit 6 increases. However, when the resistance value of the surge reduction circuit 6 increases, the loss in the resistance increases. Accordingly, the optimum value of the resistance value of the surge reduction circuit 6 is a value that can suppress the surge current to the minimum in a range not affected by this loss.

  In addition, the specific circuit configuration of the lighting device 1 of the present embodiment is not limited to the circuit configuration illustrated in FIG. 1 and can be changed as appropriate. For example, as shown in FIG. 5, the light emitting element 20 is classified into first to third light emitting units 25 to 27, and the first to third light emitting units 25 to 27 are arranged between output terminals of the DC power supply circuit 3. They may be connected in parallel. In the example of FIG. 5, the surge reduction circuit 6 includes a first inductor 61 connected in series to the first light emitting unit 25, a second inductor 62 connected in series to the second light emitting unit 26, and a third And a third inductor 63 connected in series to the light emitting unit 27. These first to third inductors 61 to 63 are all different in inductance (impedance value). In FIG. 5, the output controller is not shown.

  Thereby, since the impedance value between the DC power supply circuit 3 and the light emitting units 25 to 27 is different for each of the light emitting units 25 to 27, the surge current component is automatically generated in the first to third light emitting units 25 to 27. Are distributed in the time axis direction. Here, the surge reduction circuit 6 only needs to include at least two types of impedance elements (inductors) having different impedance values, and it is not essential that all the inductors 61 to 63 have different inductances. For example, when the first and second inductors 61 and 62 have the same inductance and only the third inductor 63 has a different inductor, both the first and second light emitting units 25 and 26 and the third light emitting unit 27, the component of the surge current is dispersed in the time axis direction.

  Further, in the surge reduction circuit 6, any of the first to third inductors 61 to 63 may be omitted (short-circuited). In this case, since the impedance value between the DC power supply circuit 3 and any one of the light emitting units 25 to 27 becomes substantially zero, loss in the surge reduction circuit 6 can be reduced.

  In the example of FIG. 5, the light emitting elements 20 of the first to third light emitting units 25 to 27 are each composed of one light emitting element 21 to 23. A series circuit or a parallel circuit may constitute each light emitting unit. The output voltage of the DC power supply circuit 3 may be any waveform, a DC waveform with a constant output voltage, a rectangular wave, a sine wave, a trapezoidal wave, a triangular wave, or the like. .

  Furthermore, as shown in FIG. 6, the surge reduction circuit 6 may have a configuration in which first to third inductors 61 to 63 are connected in series. In the example of FIG. 6, the first inductor 61 is inserted between the DC power supply circuit 3 and the first light emitting unit 25, and the second inductor 26 is interposed between the first light emitting unit 25 and the second light emitting unit 26. An inductor 62 is inserted, and a third inductor 63 is inserted between the second light emitting unit 26 and the third light emitting unit 27.

  In this configuration, the first inductor 61 is interposed between the DC power supply circuit 3 and the first light emitting unit 25, and the first and second light emitting units 26 are interposed between the DC power supply circuit 3 and the second light emitting unit 26. A series circuit of two inductors 61 and 62 is interposed. A series circuit of all first to third inductors 61 to 63 is interposed between the DC power supply circuit 3 and the third light emitting unit 27. That is, the basic inductive component common to the first to third light emitting units 25 to 27 is formed by the first inductor 61, and the first light emitting unit 25, the second light emitting unit 26, and the third light emitting unit 27. Is formed by the second and third inductors 62 and 63.

  Therefore, in the configuration of FIG. 6, the second and third inductors 62 and 63 need only cover the difference in inductance between the first to third light emitting units 25 to 27. An inductor can be used for the inductors 62 and 63.

(Embodiment 2)
The lighting device of this embodiment is different from the lighting device of Embodiment 1 in that the output control unit changes the output of the DC power supply circuit individually for each light emitting unit.

  In this embodiment, the light emitting element 20 (refer FIG. 1) is classified into the 1st-4th light emission parts 25-28, as shown in FIG. These light emitting elements 20 are individually connected between the output terminals of the DC power supply circuit 3 via switching elements 41 to 44 (hereinafter referred to as “switching elements 4” unless otherwise distinguished) for each of the light emitting sections 25 to 28. Has been. The switching elements 41 to 44 constitute an output control unit 7 together with the control unit 5, and are individually controlled to be turned on / off by the control unit 5.

  Here, each of the first to fourth light emitting units 25 to 28 includes one light emitting element 20. However, the present invention is not limited to this, and a series circuit or a parallel circuit of a plurality of light emitting elements 20 may be each light emitting unit 25 to 25. 28 may be configured. In FIG. 7, the light emitting element 20 is represented by an equivalent circuit in which a leak resistor 201, a series equivalent resistor 202, and an equivalent capacitor 203 are connected in parallel.

  The surge reduction circuit 6 includes a first inductor 61 connected in series to the first light emitting unit 25 and a second inductor 62 connected in series to the second light emitting unit 26. Further, the surge reduction circuit 6 includes a third inductor 63 connected in series to the third light emitting unit 27 and a fourth inductor 64 connected in series to the fourth light emitting unit 28. Each of the first to fourth inductors 61 to 64 functions as an impedance element that reduces a surge current. The first to fourth inductors 61 to 64 all have different inductances (impedance values). However, the surge reduction circuit 6 only needs to include at least two types of impedance elements (inductors) having different impedance values, and it is not essential that all the inductors 61 to 64 have different inductances.

  According to the lighting device 1 of the present embodiment described above, the control unit 5 individually controls on / off of the switching elements 41 to 44, so that the output control unit 7 outputs the output of the DC power supply circuit 3 to the light emitting unit 25. It can be changed individually for each ~ 28. Here, in the lighting device 1, the surge current component is automatically distributed in the time axis direction by the impedance value between the DC power supply circuit 3 and the light emitting units 25 to 28 being different for each of the light emitting units 25 to 28. Will be. Therefore, even if the ON / OFF timings of the plurality of switching elements 41 to 44 are overlapped, the surge current component is dispersed in the time axis direction, so that stress and noise applied to the DC power supply circuit 3 can be reduced. . Therefore, the output control unit 7 individually sets the on / off timings of the switching elements 41 to 44 without restricting the on / off timings of the plurality of switching elements 41 to 44 so as not to overlap. Can be controlled.

  Moreover, the control part 5 switches these switching elements 41-44 with a different period for every light emission parts 25-28 in the light control lighting mode which changes the light output of the light emitting element 20 by switching of the switching elements 41-44. Also good. Thereby, the switching timing of the first to fourth switching elements 41 to 44 is shifted, and there is an advantage that the switching frequency is dispersed and noise is reduced. Even in this case, even if the ON / OFF timings of the plurality of switching elements 41 to 44 are overlapped, the surge current component is distributed in the time axis direction, so that stress and noise applied to the DC power supply circuit 3 are reduced. Can do.

  Other configurations and functions are the same as those of the first embodiment.

(Embodiment 3)
As shown in FIG. 8, the lighting device 1 of the present embodiment includes four light emitting elements 211 to 214 and 221 to 224 arranged vertically in two rows on the front surface of the instrument main body 100 (see FIG. 2). The point used for the lighting fixture 10 (refer FIG. 2) provided with is different from the lighting device 1 of Embodiment 1. FIG.

  In the present embodiment, the light emitting elements 211 to 214 are connected in series to form the first light emitting unit 25, and the light emitting elements 221 to 224 are connected in series to form the second light emitting unit 26. The units 25 and 26 are connected in parallel between the output terminals of the DC power supply circuit 3. The surge reduction circuit 6 includes a first inductor 61 connected in series with the light emitting elements 211 to 214 of the first light emitting unit 25 and a first inductor 61 connected in series with the light emitting elements 221 to 224 of the second light emitting unit 26. Two inductors 62 are provided. The first inductor 61 and the second inductor 62 have different inductances.

  Here, the light emitting element 211 of the first light emitting unit 25, the light emitting element 222 of the second light emitting unit 26, the light emitting element 213 of the first light emitting unit 25, and the light emitting element 224 of the second light emitting unit 26 Are arranged in the vertical direction (vertical direction in FIG. 8) in this order. The light emitting element 221 of the second light emitting unit 26, the light emitting element 212 of the first light emitting unit 25, the light emitting element 223 of the second light emitting unit 26, and the light emitting element 214 of the first light emitting unit 25 are as follows. These are arranged in the vertical direction in this order. That is, the light emitting elements 20 of the first light emitting unit 25 and the light emitting elements 20 of the second light emitting unit 26 are alternately distributed in the left column and the right column in FIG.

  Here, since the light emitting elements 20 constituting the same light emitting portions 25 and 26 are connected in series, the same current flows. Since the brightness (light output) of the light emitting element 20 made of organic EL is determined by the magnitude of the flowing current, the light emitting elements 20 constituting the same light emitting sections 25 and 26 are lit with the same brightness. On the other hand, between the light emitting elements 20 connected in parallel, the magnitude of the flowing current is different due to the initial variation of internal resistance, the variation due to the change with time, and the like, and thus the brightness tends to vary. In particular, since the first inductor 61 and the second inductor 62 have different inductances, the light emitting elements 20 of the different light emitting units 25 and 26 are likely to vary in brightness.

  In the present embodiment, as described above, the light emitting elements 20 of the first light emitting unit 25 and the light emitting elements 20 of the second light emitting unit 26 are arranged in a spatially dispersed manner. The unevenness of brightness can be reduced. That is, in the case where one planar light source is configured by the plurality of light emitting elements 20 as a whole, it is possible to reduce the uneven brightness of the light emitting surface. Moreover, since the heat generated in the light emitting element 20 at the time of lighting can be spatially dispersed, local heat generation biased to one place can be prevented, and the life of the lighting fixture 10 can be extended. Further, noise generated in the plurality of light emitting elements 20 when the output of the DC power supply circuit 3 is changed can be spatially dispersed, so that the noise can be further reduced.

  Further, when one light emitting element 20 has an open failure, all the light emitting elements 20 connected in series with the light emitting element 20 are turned off. Can be dispersed. Therefore, the lighting device 1 can emit a wide range of light on the front surface of the fixture body 100 even when the light emitting element 20 is in an open failure, and can reduce the unevenness of brightness.

  In the example of FIG. 8, in each row, the light emitting elements 20 belonging to the same light emitting units 25 and 26 are alternately arranged in units of one. However, the present invention is not limited to this configuration, and the same light emitting units 25 and 26 are arranged. The light emitting elements 20 belonging to may be alternately arranged in a plurality of units. For example, the light emitting elements 211 to 214 and 221 to 224 belonging to the same light emitting units 25 and 26 may be alternately arranged in units of two. As described above, when the number of light emitting elements 20 is large, a plurality of light emitting elements 20 belonging to the same light emitting portions 25 and 26 may be adjacent to each other in each row. The output can be spatially finely distributed, and the effects of the present embodiment as described above are remarkable.

  Other configurations and functions are the same as those of the first embodiment.

  Further, the configuration of the second embodiment and the configuration of the third embodiment can be appropriately combined.

  In each of the above embodiments, the light emitting element 20 is made of an organic EL. However, the light emitting element 20 is not limited to the organic EL, and may be, for example, an LED (Light Emitting Diode). The light emitting element 20 is a combination of an organic EL and an LED, an inorganic EL panel that is another planar light source, a combination of an LED and a light guide plate that guides light emitted from the LED to emit light, a cold cathode It may be a direct type or edge light type surface light source unit having a fluorescent lamp.

DESCRIPTION OF SYMBOLS 1 Lighting device 3 (DC) power supply circuit 4,41-44 Switching element 6 Surge reduction circuit 7 Output control part 10 Lighting fixture 20-24, 211-214, 221-224 Light emitting element 25-28 Light emitting part 61-64 Inductor ( Impedance element)
100 Instrument body

Claims (8)

A power supply circuit for applying a voltage to a plurality of light emitting units having the same characteristics, each having a light emitting element and connected in parallel, and an impedance element inserted between the power supply circuit and the plurality of light emitting units A surge reduction circuit that has a light emission unit and determines a time constant of a series circuit of the impedance element and the light emission unit according to an impedance value of the impedance element, and the surge reduction circuit has at least two different impedance values A lighting device comprising the impedance element.   The lighting device according to claim 1, wherein the impedance element is an inductor.   Dimming control that includes a switching element that is inserted between the power supply circuit and the light emitting unit and controls the output of the power supply circuit to the light emitting unit, and changes the light output of the light emitting element by switching the switching element. The lighting device according to claim 1, further comprising a unit.   The lighting device according to any one of claims 1 to 3, wherein the light emitting element is an organic EL element.   An output control unit that controls an output of the power supply circuit applied to the light emitting unit is provided, wherein the output control unit aligns the timing of changing the output of the power supply circuit in the plurality of light emitting units. The lighting device according to any one of claims 1 to 4.   The output control part which controls the output of the said power supply circuit applied to the said light emission part is provided, The said output control part changes the output of the said power supply circuit separately for every said light emission part, It is characterized by the above-mentioned. The lighting device according to any one of claims 4 to 4.   Each of the light emitting units has a switching element that is inserted between the power supply circuit and the light emitting unit and controls the output of the power circuit to the light emitting unit, and the output control unit includes a plurality of the switching elements. The lighting device according to claim 6, wherein switching is performed at a different period for each light emitting unit. A lighting fixture comprising: the lighting device according to any one of claims 1 to 7; and a fixture main body provided with the light emitting element.

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