JP2018006122A - Lighting device, lighting fixture and lighting system - Google Patents

Abstract

The light output of a solid light source is smoothly changed even when the dimming ratio is relatively low. A lighting device includes a supply circuit, a constant current circuit, and a control circuit. The supply circuit 11 supplies the first current I1 corresponding to the dimming ratio to the solid light source 3 and causes the solid light source 3 to emit light having a light amount corresponding to the dimming ratio. The constant current circuit 12 is connected to the solid light source 3 in parallel. The control circuit 13 controls the supply circuit 11 and the constant current circuit 12 so that the solid-state light source 3 emits light having a light amount corresponding to the dimming ratio. The control circuit 13 controls the supply circuit 11 so as to continuously output an output current Io larger than the first current I1 at least when the dimming ratio is less than the threshold, and the output current Io and the first current The constant current circuit 12 is controlled so that the second current I2, which is a difference from I1, flows continuously to the constant current circuit 12. [Selection] Figure 1

Description

  The present invention relates to a lighting device, a lighting fixture, and a lighting system, and more particularly to a lighting device that lights a solid light source, a lighting fixture that includes the lighting device and a solid light source, and a lighting system that includes the lighting fixture.

  Conventionally, various lighting devices for dimming and lighting solid light sources such as LED elements and organic EL elements have been known (see, for example, Patent Document 1). When the solid-state light source is dimmed, the conventional lighting device controls the output current by the continuous dimming method in the range where the output current is large (the range where the dimming ratio is high), and the range where the output current is small (the dimming ratio is small). In the low range), the output current is controlled by the burst dimming method.

Japanese Patent Laying-Open No. 2015-225825

  However, in conventional lighting devices, the current is controlled by a burst dimming method depending on the current supplied to the solid light source (solid light emitting element), the voltage applied to the solid light source (solid light emitting element), and the input voltage to the switching circuit. When this occurs, a state occurs in which the output current cannot be controlled with the resolution of burst dimming. For example, the output current cannot be controlled in the off period of the MOSFET (switching element) of the switching circuit.

  In the above case, even if the indicated value of the dimming signal is changed, the output current does not change following the indicated value of the dimming signal. In other words, when the fade-in operation or the fade-out operation is performed, it becomes a state in which light rattling (flicker) is likely to occur during the burst dimming operation. This is a fatal defect for lighting equipment for production use.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a lighting device and illumination that can smoothly change the light output of a solid-state light source even when the dimming ratio is relatively low. It is to provide an appliance and a lighting system.

  A lighting device according to one embodiment of the present invention includes a supply circuit, a constant current circuit, and a control circuit. The supply circuit supplies a first current corresponding to the dimming ratio to the solid light source to emit light having a light amount corresponding to the dimming ratio from the solid light source. The constant current circuit is connected in parallel to the solid state light source. The control circuit controls the supply circuit and the constant current circuit so that the solid-state light source emits light having a light amount corresponding to the dimming ratio. The control circuit controls the supply circuit to continuously output an output current larger than the first current when at least the dimming ratio is less than a threshold, and the output current and the first The constant current circuit is controlled so that a second current, which is a difference from the current, flows continuously to the constant current circuit.

  The lighting fixture which concerns on 1 aspect of this invention is equipped with the said lighting device and the said solid light source.

  A lighting system according to an aspect of the present invention includes a plurality of the lighting fixtures and further includes a controller. The controller transmits a dimming signal indicating the dimming ratio to the plurality of lighting fixtures.

  According to the lighting device, the lighting fixture, and the lighting system according to each aspect of the present invention, the light output of the solid-state light source can be smoothly changed even when the dimming ratio is relatively low.

FIG. 1 is a circuit diagram of a lighting device according to Embodiment 1 of the present invention. FIG. 2 is an explanatory diagram of the operation of the lighting device. FIG. 3 is an explanatory diagram of the operation of the lighting device according to Embodiment 2 of the present invention. FIG. 4 is a perspective view of a lighting fixture according to Embodiment 3 of the present invention. FIG. 5 is a block diagram of an illumination system according to Embodiment 4 of the present invention.

  Hereinafter, the lighting device according to the first and second embodiments, the lighting fixture according to the third embodiment, and the lighting system according to the fourth embodiment will be described in detail with reference to the drawings.

(Embodiment 1)
As illustrated in FIG. 1, the lighting device 1 according to the first embodiment is configured to light a solid light source 3 using power from a power source 2. The lighting device 1 is used, for example, for lighting equipment for effect lighting.

  The power source 2 is, for example, an AC power source with a power source voltage frequency of 60 [Hz] or 50 [Hz]. The power supply 2 supplies a power supply voltage to the lighting device 1.

  The solid light source 3 includes a plurality (three in the example of FIG. 1) of solid light emitting elements 31. The plurality of solid state light emitting elements 31 constitutes a series circuit. Each solid light emitting element 31 is, for example, a light emitting diode. The solid state light emitting element 31 is a red light emitting diode that emits red light (for example, visible light of 615 to 635 [nm]) as a light emitting diode. The solid light emitting element 31 may be a green light emitting diode that emits green light (for example, visible light of 520 to 535 [nm]). The solid light emitting element 31 may be a blue light emitting diode that emits blue light (for example, visible light of 464 to 475 [nm]). Moreover, each solid light emitting element 31 may be an organic electroluminescent element instead of a light emitting diode.

  The lighting device 1 according to the first embodiment includes a supply circuit 11, a constant current circuit 12, and a control circuit 13. As the dimming method of the solid light source 3 by the lighting device 1, a continuous dimming method (DC current dimming method) for increasing or decreasing the direct current supplied to the solid light source 3 is used.

  The supply circuit 11 is configured to supply the first current I1 corresponding to the dimming ratio to the solid-state light source 3 and to emit light having a light amount corresponding to the dimming ratio from the solid-state light source 3. The supply circuit 11 includes an input filter 14, a rectifier circuit 15, a step-up chopper circuit 16, and a step-down chopper circuit 17.

  The input filter 14 is configured to remove unnecessary frequency components such as noise. More specifically, the input filter 14 is composed of a high-frequency cutoff filter, and is configured to, for example, pass harmonics (60 [Hz] and 50 [Hz]) of the power supply voltage of the power supply 2 to cut off harmonic components. Has been. Further, the input filter 14 is configured to block the harmonic components so that the harmonic components from the boost chopper circuit 16 and the like do not pass to the power supply 2 side.

  The rectifier circuit 15 outputs a rectified voltage obtained by rectifying (full-wave rectification, half-wave rectification) the AC voltage input via the input filter 14. The rectifier circuit 15 is configured by a diode bridge, for example.

  The step-up chopper circuit 16 is configured as a power factor correction circuit. The step-up chopper circuit 16 includes a switching element Q1, an inductor (choke coil) L1, a resistor R1, a diode D1, and a smoothing capacitor C1. The switching element Q1 is composed of, for example, an n-channel enhancement type MOSFET (field effect transistor). On the high potential side of the rectifier circuit 15, a series circuit of an inductor L1 and a diode D1 is connected. A series circuit of the switching element Q1 and the resistor R1 is connected between the output terminals of the rectifier circuit 15 via the inductor L1. Further, a smoothing capacitor C <b> 1 is connected between the output terminals of the boost chopper circuit 16. Then, when the switching element Q1 is turned on / off, a boosted voltage is generated between both ends of the smoothing capacitor C1.

  The step-down chopper circuit 17 includes a switching element Q2, an inductor L2, a diode D2, a smoothing capacitor C2, and a resistor R2. The switching element Q2 is composed of, for example, an n-channel enhancement type MOSFET (field effect transistor). In the step-down chopper circuit 17, a switching element Q2, an inductor L2, a smoothing capacitor C2, and a resistor R2 are electrically connected in series in this order between both ends of the smoothing capacitor C1. A series circuit of the switching element Q2, the diode D2, and the resistor R2 is electrically connected between the output terminals of the step-up chopper circuit 16 (between both ends of the smoothing capacitor C1). A series circuit of an inductor L2 and a smoothing capacitor C2 is electrically connected between the anode and cathode of the diode D2. The solid light source 3 is electrically connected between both ends of the smoothing capacitor C2.

  Since the smoothing capacitor C2 is electrically connected in parallel to the output of the step-down chopper circuit 17, that is, the difference between the peak value and the bottom value of the output current Io is reduced, the waveform of the output current Io is It approaches a DC waveform with little current ripple. At this time, the voltage across the smoothing capacitor C <b> 2 is substantially equal to the forward voltage of the solid state light source 3. The forward voltage of the solid light source 3 is determined according to the dimming ratio according to the forward current-forward voltage characteristics of the solid light source 3.

  The constant current circuit 12 is electrically connected to the solid light source 3 in parallel. The constant current circuit 12 includes two resistors R3 and R4 and a switching element Q3. Between both ends of the smoothing capacitor C2 of the step-down chopper circuit 17, a resistor (resistive element) R4, a switching element Q3, and a resistor R3 are electrically connected in series in this order. The resistor R4 is connected to the high potential side of the step-down chopper circuit 17, and the resistor R3 is connected to the low potential side of the step-down chopper circuit 17. The switching element Q3 is composed of, for example, an n-channel enhancement and a MOSFET (field effect transistor). The switching element Q3 operates in a linear region (active region) according to a constant current control signal S3 described later. In other words, the switching element Q3 increases or decreases the drain current as the second current I2 flowing through the constant current circuit 12 in accordance with the constant current control signal S3. The magnitude of the second current I2 flowing through the constant current circuit 12 is adjusted according to the instruction value of the constant current control signal S3.

  The control circuit 13 is configured to control the supply circuit 11 and the constant current circuit 12 so that the solid-state light source 3 emits light having a light amount corresponding to the dimming ratio. The control circuit 13 includes a boost control circuit 131, a control unit 132, a step-down control circuit 133, and a constant current control circuit 134.

  The dimming signal S1 input from the outside to the control circuit 13 is a PWM (Pulse With Modulation) signal having a different duty ratio (ratio of on period to one cycle) depending on the dimming ratio. The control circuit 13 receives the dimming signal S1 from an external device such as a controller called a dimming console. The dimming signal S1 may be a signal of a standardized communication protocol such as DMX512. The dimming signal S1 may be a signal in accordance with a wired communication system such as a UART (Universal Asynchronous Transmitter).

  The step-up control circuit 131 is configured to control the step-up operation of the step-up chopper circuit 16 by switching the on / off of the switching element Q1. More specifically, the boost control circuit 131 is configured to detect the voltage across the resistor R1 and control the duty ratio of the switching element Q1 to make the voltage across the smoothing capacitor C1 constant. The boost control circuit 131 compares the current flowing through the inductor L1 detected by a current detection unit (not shown) with a threshold value, and determines the on-timing of the switching element Q1. Further, the boost control circuit 131 compares the voltage across the resistor R1 (current flowing through the switching element Q1) with a threshold value to determine the off timing of the switching element Q1. The step-up control circuit 131 controls the step-up voltage generated at both ends of the smoothing capacitor C1 to a predetermined voltage by adjusting the ON timing and the OFF timing of the switching element Q1.

  The control unit 132 includes a microcontroller having a CPU (Central Processing Unit), a memory, and the like. The control unit 132 is configured to control the step-down chopper circuit 17 and dimm the light emitted from the solid-state light source 3 when the program stored in the memory is executed by the CPU. The control unit 132 receives the dimming signal S1 from the outside, and operates so as to match the brightness of the light emitted from the solid-state light source 3 with the brightness required by the dimming signal S1.

  The control unit 132 stores a dimming table in advance. The dimming table shows the relationship between the duty ratio of the dimming signal S1 and the dimming ratio. The dimming ratio decreases as the duty ratio of the dimming signal S1 increases. Specifically, when the duty ratio of the dimming signal S1 is 0 to 5%, the dimming ratio is 100% (all lighting), and when the duty ratio of the dimming signal S1 is 95 to 100%, The dimming ratio is 0% (off). When the duty ratio of the dimming signal S1 is 5 to 95%, the dimming ratio decreases as the duty ratio of the dimming signal S1 increases.

  When the control unit 132 receives the dimming signal S1 from the outside, the control unit 132 refers to the dimming table and obtains the dimming ratio according to the duty ratio of the dimming signal S1. The control unit 132 generates a step-down control signal S2 according to the obtained dimming ratio, and outputs the step-down control signal S2 to the step-down control circuit 133. The step-down control signal S2 is a signal for instructing the dimming ratio.

  The step-down control circuit 133 controls the step-down operation of the step-down chopper circuit 17 by switching on / off the switching element Q2 of the step-down chopper circuit 17 based on the step-down control signal S2. Specifically, the step-down control circuit 133 determines the ON timing of the switching element Q2 by comparing the current flowing through the inductor L2 detected by a current detection unit (not shown) with a threshold value. Further, the step-down control circuit 133 compares the voltage across the resistor R2 (current flowing through the switching element Q2) with a threshold value, and determines the OFF timing of the switching element Q2. That is, the step-down control circuit 133 adjusts the ON timing and the OFF timing of the switching element Q2 according to the dimming ratio indicated by the step-down control signal S2. Thereby, the step-down control circuit 133 controls the step-down chopper circuit 17 so that the current (output current Io) flowing through the solid-state light source 3 becomes a current value corresponding to the dimming ratio.

  By the way, in the control circuit 13, the control unit 132 controls the supply circuit 11 so that the supply circuit 11 continuously outputs an output current Io larger than the first current I1 at least when the dimming ratio is less than the threshold value. To do. Furthermore, in the above case, the control unit 132 is configured so that the second current I2, which is the difference between the output current Io and the first current I1, continuously flows to the constant current circuit 12 while maintaining a predetermined value. 12 is controlled.

  In the control circuit 13 of the first embodiment, the control unit 132 controls the supply circuit 11 so as to continuously output the output current Io larger than the first current I1 regardless of the dimming ratio, and The constant current circuit 12 is controlled such that the second current I2 flows continuously to the constant current circuit 12.

  The control unit 132 outputs the constant current control signal S3 to the constant current control circuit 134 when at least the dimming ratio obtained from the dimming signal S1 is less than the threshold value. In the first embodiment, the control unit 132 outputs the constant current control signal S3 to the constant current control circuit 134 regardless of the value of the dimming ratio obtained from the dimming signal S1. In other words, the control unit 132 outputs the constant current control signal S3 to the constant current control circuit 134 even if the dimming ratio is less than the threshold value or the dimming ratio is greater than or equal to the threshold value. The constant current control signal S3 is a signal for instructing the magnitude (current value) of the second current I2 flowing through the constant current circuit 12. The constant current control signal S3 of the first embodiment is, for example, a PWM signal having the same duty ratio regardless of the dimming ratio. That is, the second current I2 flowing through the constant current circuit 12 is a constant value (fixed value) regardless of the dimming ratio.

  The constant current control circuit 134 controls the switching element Q3 of the constant current circuit 12 to operate in a linear region by a constant current control signal S3 from the control unit 132. The constant current control circuit 134 adjusts the voltage value of the gate-source voltage of the switching element Q3 so that the second current I2 flowing through the constant current circuit 12 becomes a constant value.

  Next, the operation of the lighting device 1 according to the first embodiment will be described with reference to FIG.

  First, when the control unit 132 of the control circuit 13 receives the dimming signal S1 instructing a specific dimming ratio, the control unit 132 refers to the dimming table and obtains the dimming ratio from the duty ratio of the dimming signal S1. Thereafter, the control unit 132 adjusts the output current Io output from the step-down chopper circuit 17 so that the first current I1 flowing through the solid-state light source 3 has a current value corresponding to the dimming ratio. That is, as shown in FIG. 2, the control unit 132 performs step-down control so that the output current Io is the sum of the first current I1 flowing through the solid-state light source 3 and the second current I2 flowing through the constant current circuit 12. The signal S2 is output to the step-down control circuit 133.

  For example, the first current I1 required for fully lighting the solid state light source 3 is 500 mA (100% in FIG. 2), and the second current I2 flowing through the constant current circuit 12 is 50 mA (10% in FIG. 2). And When the solid state light source 3 is turned on with full lighting (dimming ratio 100%), the control unit 132 sends the step-down control signal S2 to the step-down control circuit 133 so that the output current Io is 550 mA (110% in FIG. 2). Output. Further, when the first current I1 to the solid state light source 3 is set to 50 mA (10% when fully lit), the control unit 132 controls the step-down control signal so that the output current Io is 100 mA (20% in FIG. 2). S2 is output to the step-down control circuit 133.

  The step-down control circuit 133 adjusts the ON timing and the OFF timing of the switching element Q2 based on the step-down control signal S2. Thereby, the step-down chopper circuit 17 controls the output current Io to a current value corresponding to a specific dimming ratio, and outputs it to the solid state light source 3 and the constant current circuit 12.

  Further, when the control unit 132 receives the dimming signal S1, the control unit 132 outputs a constant current control signal S3 to the constant current control circuit 134 so that a constant second current I2 flows through the constant current circuit 12. The constant current control circuit 134 controls the switching element Q3 to operate in the linear region based on the constant current control signal S3. As a result, a constant second current I2 flows through the constant current circuit 12.

  From the above, the first current I1 obtained by subtracting the second current I2 flowing through the constant current circuit 12 from the output current Io of the step-down chopper circuit 17 flows through the solid-state light source 3. That is, the first current I1 corresponding to the dimming ratio flows through the solid light source 3. Thereby, the solid light source 3 can be lighted with the brightness according to the light control ratio.

  The lighting device 1 according to the first embodiment described above includes the supply circuit 11, the constant current circuit 12, and the control circuit 13. The supply circuit 11 supplies the first current I1 corresponding to the dimming ratio to the solid light source 3 and causes the solid light source 3 to emit light having a light amount corresponding to the dimming ratio. The constant current circuit 12 is electrically connected to the solid light source 3 in parallel. The control circuit 13 controls the supply circuit 11 and the constant current circuit 12 so that the solid-state light source 3 emits light having a light amount corresponding to the dimming ratio. The control circuit 13 controls the supply circuit 11 so that the supply circuit 11 continuously outputs an output current Io larger than the first current I1 at least when the dimming ratio is less than the threshold value. Further, in the above case, the control circuit 13 controls the constant current circuit 12 so that the second current I2, which is the difference between the output current Io and the first current I1, flows continuously to the constant current circuit 12.

  In the lighting device 1 according to the first embodiment, the supply circuit 11 outputs the output current Io that is larger than the first current I1 supplied to the solid-state light source 3 at least when the dimming ratio is less than the threshold value. To control. Further, in the above case, the lighting device 1 controls the constant current circuit 12 so that the second current I2, which is the difference between the output current Io and the first current I1, flows through the constant current circuit 12. Thereby, according to the lighting device 1 according to the first embodiment, even when the dimming ratio is relatively low, for example, at the time of fade-in or fade-out, the light output of the solid-state light source 3 compared to the case of burst dimming. Flickering can be reduced. As a result, the light output of the solid light source 3 can be changed smoothly. That is, in the lighting device 1 according to the first embodiment, it is possible to improve the fade performance when fade-in or fade-out is performed.

  Further, when the continuous light control method is used as the light control method of the solid light source 3 by the lighting device 1, unlike the burst light control method, a low-capacitance capacitor can be used as the smoothing capacitor C2. More specifically, in the case of the burst dimming method, a large-capacitance capacitor is required as a smoothing capacitor as a countermeasure against video flicker. On the other hand, in this embodiment, since a continuous light control method is used, a large-capacity capacitor is not necessary as the smoothing capacitor C2, and a low-capacitance capacitor is sufficient. Thereby, the charge time of the smoothing capacitor C2 can be shortened. As a result, the output current Io and the first current I1 can be adjusted to current values corresponding to the dimming ratio in a short time. For this reason, the light output of the solid light source 3 can be changed more smoothly during fade-in or fade-out.

  In the lighting device 1 according to the first embodiment, the second current I2 is preferably a constant value regardless of the dimming ratio. The control circuit 13 controls the supply circuit 11 so as to continuously output an output current Io larger than the first current I1 regardless of the dimming ratio, and the second current I2 is constant current circuit. It is preferable to control the constant current circuit 12 so as to continuously flow to the current 12.

  In the lighting device 1 according to the first embodiment, the constant current circuit 12 preferably includes the switching element Q3. The switching element Q3 is electrically connected to the output terminal of the supply circuit 11. The control circuit 13 preferably controls the switching element Q3 to change the magnitude of the second current I2.

  In the lighting device 1 according to the first embodiment, the constant current circuit 12 preferably includes a resistance element (resistance R4). The resistance element is electrically connected in series to the switching element Q3.

  In the lighting device 1 according to the first embodiment, in the constant current circuit 12, the switching element Q3 and the resistance element (resistance R4) are electrically connected in series. Thereby, since the voltage applied to switching element Q3 can be reduced, the loss in switching element Q3 can be reduced.

(Embodiment 2)
The lighting device 1 according to the second embodiment is different from the lighting device 1 according to the first embodiment in that the second current I2 flows through the constant current circuit 12 only when the dimming ratio is less than the threshold value. In addition, about the component similar to the lighting device 1 which concerns on Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The control circuit 13 of the second embodiment controls the constant current circuit 12 so that the second current I2 flows through the constant current circuit 12 only when the dimming ratio is less than the threshold value. Note that description of functions similar to those of the control circuit 13 of the first embodiment is omitted.

  More specifically, when the dimming ratio is greater than or equal to the threshold value, the control circuit 13 controls the supply circuit 11 so that the output current Io is the same as the first current I1, and the second current I2 is The constant current circuit 12 is controlled so as not to flow to the constant current circuit 12. On the other hand, when the dimming ratio is less than the threshold value, the control circuit 13 controls the supply circuit 11 so that the output current Io is larger than the first current I1, and the second current I2 is continuously constant. The constant current circuit 12 is controlled so as to flow through the circuit 12.

  The control unit 132 according to the second embodiment outputs the constant current control signal S3 to the constant current control circuit 134 only when the dimming ratio is less than the threshold value. The control unit 132 according to the second embodiment stores a dimming table that represents the relationship between the duty ratio of the constant current control signal S3 and the dimming ratio. That is, the dimming table represents the relationship between the second current I2 and the dimming ratio. More specifically, in the dimming table, when the dimming ratio is greater than or equal to the threshold, the second current I2 is 0, and when the dimming ratio is less than the threshold, the second current I2 decreases as the dimming ratio decreases. The relationship between the second current I2 and the dimming ratio is defined so that the current value of the current increases.

  Next, the operation of the lighting device 1 according to the second embodiment will be described with reference to FIG. The threshold value is the dimming ratio when the first current I1 is 50 mA (10% when all the lights are on).

  First, when the control unit 132 of the control circuit 13 receives the dimming signal S1 instructing a specific dimming ratio, the control unit 132 refers to the dimming table and obtains the dimming ratio from the duty ratio of the dimming signal S1. Thereafter, the control unit 132 adjusts the output current Io output from the step-down chopper circuit 17 so that the first current I1 flowing through the solid-state light source 3 has a current value corresponding to the dimming ratio. That is, as shown in FIG. 3, when the dimming ratio is equal to or greater than the threshold value, the output current Io is the sum of the first current I1 flowing through the solid-state light source 3 and the second current I2 flowing through the constant current circuit 12. As described above, the control unit 132 outputs the step-down control signal S2 to the step-down control circuit 133. On the other hand, when the dimming ratio is less than the threshold value, the second current I2 does not flow through the constant current circuit 12, and thus the control unit 132 is configured so that the output current Io is equal to the first current I1 flowing through the solid-state light source 3. Outputs the step-down control signal S2 to the step-down control circuit 133.

  The step-down control circuit 133 adjusts the ON timing and the OFF timing of the switching element Q2 based on the step-down control signal S2. Thereby, the step-down chopper circuit 17 controls the output current Io to a current value corresponding to a specific dimming ratio, and outputs it to the solid state light source 3 and the constant current circuit 12.

  When the control unit 132 receives the dimming signal S1, as shown in FIG. 3, the control unit 132 controls the constant current so that the second current I2 flows through the constant current circuit 12 only when the dimming ratio is less than the threshold. The signal S3 is output to the constant current control circuit 134. The constant current control circuit 134 controls the switching element Q3 to operate in the linear region based on the constant current control signal S3. As a result, a constant second current I2 flows through the constant current circuit 12. On the other hand, when the dimming ratio is greater than or equal to the threshold, the control unit 132 does not output the constant current control signal S3 to the constant current control circuit 134. The switching element Q3 remains off, and the second current I2 does not flow through the constant current circuit 12.

  From the above, when the dimming ratio is greater than or equal to the threshold value, the output current Io of the step-down chopper circuit 17 flows to the solid state light source 3 as the first current I1. On the other hand, when the dimming ratio is less than the threshold value, the first current I1 obtained by subtracting the second current I2 flowing through the constant current circuit 12 from the output current Io of the step-down chopper circuit 17 flows through the solid-state light source 3. In either case, the first current I1 corresponding to the dimming ratio flows through the solid light source 3. Thereby, the solid light source 3 can be lighted with the brightness according to the light control ratio.

  For example, the first current I1 required for fully lighting the solid light source 3 is 500 mA (100% in FIG. 3), and the second current I2 flowing through the constant current circuit 12 is 50 mA (10% in FIG. 3). And When the solid-state light source 3 is turned on at full lighting (dimming ratio 100%), the control unit 132 sends the step-down control signal S2 to the step-down control circuit 133 so that the output current Io is 500 mA (100% in FIG. 3). Output. On the other hand, when the first current I1 to the solid-state light source 3 is set to be less than 50 mA (10% when fully lit), the control unit 132 performs step-down control so that the output current Io is 50 mA (10% in FIG. 3). The signal S2 is output to the step-down control circuit 133, and the constant current control signal S3 is output to the constant current control circuit 134.

  In the lighting device 1 according to the second embodiment described above, the control circuit 13 controls the supply circuit 11 so that the output current Io is equal to the first current I1 when the dimming ratio is equal to or greater than the threshold. It is preferable. Further, in the above case, the control circuit 13 preferably controls the constant current circuit 12 so that the second current I2 does not flow to the constant current circuit 12. When the dimming ratio is less than the threshold value, the control circuit 13 preferably controls the supply circuit 11 so that the output current Io is larger than the first current I1. Further, in the above case, the control circuit 13 preferably controls the constant current circuit 12 so that the second current I2 flows continuously to the constant current circuit 12.

(Embodiment 3)
Hereinafter, the lighting fixture 4 according to Embodiment 3 will be described with reference to FIG. The luminaire 4 according to the third embodiment is a so-called horizont light that is used for illuminating a background wall (horizont) such as a studio or a stage of a television station.

  As illustrated in FIG. 4, the lighting fixture 4 according to the third embodiment includes a light source unit 5 as a solid light source and a power supply unit 6. In the following description, in FIG. 4, front and rear, left and right, and up and down directions are defined. That is, the left side of FIG. 4 is the front, the right is the back, the top of the page of FIG. 2 is the left, and the bottom is the right.

  The light source unit 5 includes four LED modules 50, a first housing 51, a reflector plate block 52, and a heat radiating plate block 53. Each LED module 50 is configured by mounting a plurality of solid state light emitting elements on the surface of a rectangular substrate.

  The 1st housing | casing 51 is formed in the rectangular parallelepiped shape with the metal plate. The first casing 51 has a rectangular window hole 510 on the front surface. Inside the first housing 51, four LED modules 50 are accommodated in two rows in the vertical and horizontal directions so that the surface faces the window hole 510.

  The reflection plate block 52 includes a plurality of reflection plates 520 and a light shielding plate 521. The plurality of reflection plates 520 and the light shielding plate 521 are disposed in the first housing 51 between the window hole 510 and the surface of each LED module 50, and the light distribution from each LED module 50 is distributed. Is configured to control.

  The heat sink block 53 includes a large number of heat sinks 530. The plurality of heat sinks 530 are arranged at regular intervals along the thickness direction. The heat sink block 53 is provided on the rear surface of the first housing 51. In addition, it is preferable that the heat sink block 53 is thermally coupled to the four LED modules 50 (substrates thereof) in the first housing 51.

  The power supply unit 6 includes a circuit block (lighting device 1) including an input filter 14, a rectifier circuit 15, a step-up chopper circuit 16, a step-down chopper circuit 17, a constant current circuit 12, and a control circuit 13, and a second that houses the circuit block. A housing 60 and a pair of arms 61 are provided. The circuit block is the lighting device 1 of the first or second embodiment.

  The 2nd housing | casing 60 is formed in the flat rectangular parallelepiped shape with the metal plate, and is comprised so that a circuit block may be accommodated in an inside. The pair of arms 61 are provided so as to rise upward from the left and right ends of the second housing 60. The pair of arms 61 are formed so as to gradually narrow the width dimension in the front-rear direction toward the tip (upper end). Insertion holes through which the bolts of so-called knob bolts 62 are inserted are provided at the tip portions of the respective arms 61. That is, the pair of arms 61 are configured to rotatably support the light source unit 5 by screwing bolts inserted through the insertion holes in the distal end portion into female screws provided on the left and right side surfaces of the first housing 51. Has been.

  Next, the use state of the lighting fixture 4 which concerns on Embodiment 3 is demonstrated. The luminaire 4 according to the third embodiment is installed on, for example, a floor facing the background wall surface of the light source unit 5 and away from the background wall surface. The luminaire 4 according to Embodiment 3 can irradiate illumination light substantially uniformly from the lower part close to the floor of the background wall surface to the upper part.

  The lighting fixture 4 which concerns on Embodiment 3 demonstrated above is provided with the lighting device 1 and the solid light source (light source unit 5).

  Also in the lighting fixture 4 according to the third embodiment, when at least the dimming ratio is less than the threshold, the control circuit 13 of the lighting device 1 has an output larger than the first current I1 supplied to the solid light source (light source unit 5). The supply circuit 11 is controlled so that the supply circuit 11 outputs the current Io. Further, in the above case, the control circuit 13 of the lighting device 1 controls the constant current circuit 12 so that the second current I2, which is the difference between the output current Io and the first current I1, flows through the constant current circuit 12. Thereby, also in the lighting fixture 4 which concerns on Embodiment 3, even when it is a case where a dimming ratio is comparatively low, such as at the time of fade-in / fade-out, for example like Embodiment 1, it is solid compared with the case of burst dimming. Flickering of the light output of the light source can be reduced. As a result, the light output of the solid light source can be changed smoothly.

  As a modification of the third embodiment, the lighting fixture 4 is not limited to a monochromatic light source (light source unit 5), and may include a solid light source (light source unit) that emits light of a plurality of colors. In this case, the luminaire 4 includes, for example, a solid light emitting element that emits red light, a solid light emitting element that emits green light, and a solid light emitting element that emits blue light as solid light emitting elements of the solid light source. Furthermore, the luminaire 4 may include a solid light emitting element that emits white light.

  Moreover, the lighting fixture 4 is not limited to a horizontal light, The lighting fixture used for another use may be sufficient.

(Embodiment 4)
Hereinafter, the illumination system 7 according to Embodiment 4 will be described with reference to FIG. As shown in FIG. 5, the lighting system 7 according to the fourth embodiment includes a plurality of lighting fixtures 4 and a dimming console 8 as a controller. The plurality of lighting fixtures 4 are sent and connected to the dimming console 8 via the communication cable 80. The dimming console 8 transmits a dimming signal S1 of a standardized communication protocol such as DMX512 to the plurality of lighting fixtures 4 via the communication cable 80. The plurality of lighting fixtures 4 receives the dimming signal S <b> 1 transmitted from the dimming console 8 by the control circuit 13, and controls the step-down chopper circuit 17 and the constant current circuit 12 by the control circuit 13.

  The lighting system 7 according to the fourth embodiment described above includes a plurality of lighting fixtures 4 and further includes a controller (a dimming console 8). The controller transmits a dimming signal indicating the dimming ratio to the plurality of lighting fixtures 4.

  Also in the lighting system 7 according to the fourth embodiment, at least when the dimming ratio is less than the threshold value, the control circuit 13 of the lighting device 1 supplies an output current Io that is larger than the first current I1 supplied to the solid-state light source 3. The supply circuit 11 is controlled so that the circuit 11 outputs. Further, in the above case, the control circuit 13 of the lighting device 1 controls the constant current circuit 12 so that the second current I2, which is the difference between the output current Io and the first current I1, flows through the constant current circuit 12. Thereby, also in the illumination system 7 according to the fourth embodiment, as in the first embodiment, even when the dimming ratio is relatively low, for example, at the time of fade-in and fade-out, the solid state is compared with the case of the burst dimming. The flicker of the light output of the light source 3 can be reduced. As a result, the light output of the solid light source 3 can be changed smoothly.

  The configuration described in each of the above embodiments is merely an example of the present invention. The present invention is not limited to the above-described embodiment, and various modifications can be made according to design or the like as long as the technical idea according to the present invention is not deviated.

DESCRIPTION OF SYMBOLS 1 Lighting device 11 Supply circuit 12 Constant current circuit 13 Control circuit 3 Solid light source 4 Lighting fixture 7 Lighting system 8 Light control console (controller)
I1 1st current I2 2nd current Io Output current Q3 Switching element R4 Resistance (resistance element)

Claims (7)

A supply circuit for supplying a first current corresponding to the dimming ratio to the solid-state light source and emitting light of a light amount corresponding to the dimming ratio from the solid-state light source;
A constant current circuit connected in parallel to the solid state light source;
A control circuit that controls the supply circuit and the constant current circuit so that the solid-state light source emits light having a light amount corresponding to the dimming ratio;
The control circuit controls the supply circuit to continuously output an output current larger than the first current when at least the dimming ratio is less than a threshold, and the output current and the first The lighting device, wherein the constant current circuit is controlled such that a second current that is a difference from the current flows continuously to the constant current circuit. The second current is a constant value regardless of the dimming ratio,
The control circuit controls the supply circuit so as to continuously output the output current larger than the first current regardless of the dimming ratio, and the second current is the constant current. The lighting device according to claim 1, wherein the constant current circuit is controlled so as to continuously flow in the current circuit. The control circuit includes:
When the dimming ratio is equal to or greater than the threshold value, the supply circuit is controlled so that the output current is the same as the first current, and the second current does not flow to the constant current circuit. To control the constant current circuit,
When the dimming ratio is less than the threshold value, the supply circuit is controlled so that the output current is larger than the first current, and the second current continuously flows to the constant current circuit. The lighting device according to claim 1, wherein the constant current circuit is controlled. The constant current circuit includes a switching element electrically connected to an output end of the supply circuit,
The lighting device according to claim 1, wherein the control circuit controls the switching element to change the magnitude of the second current.   The lighting device according to claim 4, wherein the constant current circuit includes a resistance element connected in series to the switching element. The lighting device according to any one of claims 1 to 5,
A lighting apparatus comprising: the solid-state light source. A plurality of lighting fixtures according to claim 6,
A lighting system further comprising a controller that transmits a dimming signal indicating the dimming ratio to the plurality of lighting fixtures.

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