DE102017114525A1 - LIGHTING DEVICE, LIGHTING BODY, LIGHTING SYSTEM AND PROGRAM - Google Patents

Abstract

An object of the present invention is to enable a smooth change of a light output from a solid-state light source even with a relatively small dimming ratio. In a lighting device (1), a control circuit (13) controls a supply circuit (11) and a constant current circuit (12) such that a solid-state light source (3) outputs light in an amount according to the dimming ratio. The control circuit (13) controls the feeding circuit (11) to continuously output an output current (Io) larger than a first current (I1), and controls the constant current circuit (12) to supply a second current (I2) having a current Difference between the output current (Io) and the first current (I1) is to allow to flow continuously through the constant current circuit (12), at least when the dimming ratio is smaller than a threshold value.

Description

Technical area

The present invention relates to lighting devices, lighting fixtures, lighting systems and programs, and more particularly to a lighting device configured to illuminate a solid state light source, a lighting fixture including the lighting fixture and the solid state light source, a lighting system including the lighting fixture, and a program suitable for the Lighting device is used.

State of the art

Various types of lighting devices have been known which are designed to dim and illuminate a solid state light source, such as a light emitting diode (LED) element or an organic electroluminescence (EL) element (see, for example JP 2015-225825 A (hereinafter referred to as "Document 1")). The known lighting device is designed to dim and illuminate the solid-state light source to control the output current by a continuous dimming method in an area where an output current is large (high dimming ratio area) and the output current by a burst dimming method in one Control range in which the output current is low (range with low dimming ratio).

In the known lighting device, however, a current supplied to the solid-state light source (solid-state light emitting element), a voltage applied to the solid-state light source (solid-state light emitting element) or an input voltage to a circuit may cause a state where the output current does not coincide the resolution of burst dimming can be controlled when the output current is controlled by the burst dimming method. For example, the output current may not be controlled during an off period of a MOSFET (switching element) of the circuit.

In the case described above, the output current does not change to follow the indicated value of a dimming signal even if the specified value of the dimming signal is changed. D. Performing a fade operation results in a condition where flicker of light easily occurs during the operation of burst dimming. This is a major drawback to lighting fixtures used to produce scenic effects.

Brief description of the invention

In view of the foregoing, an object of the present invention is to provide a lighting device, a lighting fixture, a lighting system, and a program that enables a smooth change of a light output from a solid-state light source even with a relatively small dimming ratio.

A lighting apparatus according to one aspect of the present invention includes a supply circuit, a constant current circuit, and a control circuit. The supply circuit is configured to supply a first current according to a dimming ratio to a solid-state light source to cause the solid-state light source to emit light in an amount according to the dimming ratio. The constant current circuit is connected in parallel with the solid-state light source. The control circuit is configured to control the supply circuit and the constant current circuit to cause the solid-state light source to emit light in the amount according to the dimming ratio. At least when the dimming ratio is smaller than a threshold value, the control circuit controls the feeding circuit to cause the feeding circuit to continuously output an output current larger than the first current, and controls the constant current circuit to produce a second current representing a difference between the output current and the first current is to allow to flow continuously through the constant current circuit.

A lighting fixture according to an aspect of the present invention includes the lighting apparatus and the solid-state light source.

A lighting system according to one aspect of the present invention includes a plurality of lighting fixtures and a controller. The controller is configured to transmit a dimming signal indicative of the dimming ratio to the lighting fixtures.

A program according to one aspect of the present invention is a program for making a computer included in the control circuit of the lighting device, at least when the dimming ratio is smaller than the threshold, a function of controlling the feeding circuit to the feeding circuit thereto to continuously output the output current larger than the first current and to realize the constant current circuit to allow the second current, which is a difference between the output current and the first current, to flow continuously through the constant current circuit ,

Brief description of the drawings

1 Fig. 10 is a circuit diagram illustrating a lighting apparatus according to a first embodiment of the present invention;

2 FIG. 10 is an exemplary diagram illustrating the operation of the lighting apparatus; FIG.

3 Fig. 10 is an exemplary diagram illustrating the operation of a lighting apparatus according to a second embodiment of the present invention;

4 Fig. 15 is a perspective view illustrating a lighting fixture according to a third embodiment of the present invention; and

5 FIG. 10 is a block diagram illustrating an illumination system according to a fourth embodiment of the present invention. FIG.

Description of embodiments

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

First Embodiment

As in 1 is shown, is a lighting device 1 formed according to a first embodiment, to a solid-state light source 3 by using electrical power from a power supply 2 to illuminate. The lighting device 1 is used in a lighting fixture, for example for illuminating scenic effects.

The power supply 2 For example, an AC power supply whose power supply voltage has a frequency of 60 Hz or 50 Hz. The power supply 2 leads the power supply voltage of the lighting device 1 to.

The solid-state light source 3 includes solid state light emitting elements 31 (in 1 three solid state light emitting elements 31 ). The solid state light emitting elements 31 form a series connection. Each solid-state light emitting element 31 is for example a light emitting diode. The solid state light emitting elements 31 are red light-emitting diodes, such as light-emitting diodes, which emit red light (visible light having a wavelength of, for example, 615 nm to 635 nm). The solid state light emitting elements 31 may be green light emitting diodes emitting green light (visible light having a wavelength of, for example, 520 nm to 535 nm). The solid state light emitting elements 31 may be blue light emitting diodes emitting a blue light (visible light having a wavelength of, for example, 464 nm to 475 nm). Further, not every solid state light emitting element needs 31 a light emitting diode, but may be, for example, an organic electroluminescent element.

The lighting device 1 According to the first embodiment, a feeding circuit includes 11 , a constant current circuit 12 and a control circuit 13 , As a method for dimming the solid-state light source 3 through the lighting device 1 describes a method of continuous dimming (DC dimming method) for increasing and decreasing a direct current flowing to the solid-state light source 3 is supplied. That is, the continuous dimming method is a method of changing the magnitude of a first current I1 that is continuous with the solid-state light source 3 is supplied.

The feeding circuit 11 is formed to be the first current I1 according to a dimming ratio of the solid-state light source 3 feed to the solid state light source 3 to cause light to emit in an amount according to the dimming ratio. The feeding 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 designed to remove unnecessary frequency components, such as noise. In particular, the input filter includes 14 a high-frequency notch filter and is designed, for example, to provide a passage of frequency components (60 Hz or 50 Hz) of a power supply voltage of the power supply 2 to enable and disable a harmonic component. Further, the input filter 14 designed to lock the harmonic component, to prevent the harmonic component of the step-up chopper circuit 16 o. Ä. at the power supply 2 arrives.

The rectifier circuit 15 directs an AC voltage (performs a full wave rectification or half wave rectification thereof) equal to that through the input filter 14 is input to output a rectified voltage from a pair of output terminals. The rectifier circuit 15 includes, for example, a diode bridge.

The step-up chopper circuit 16 is formed as a power factor correction circuit. The step-up chopper circuit 16 includes a switching element Q1, an inductor (inductor) L1, a resistor R1, a diode D1 and a smoothing capacitor C1. The switching element Q1 includes, for example, an n-channel enhancement MOSFET (Field Effect Transistor). The rectifier circuit 15 has a high-potential side connected to a series connection of the inductor L1 and the diode D1. More specifically, the series connection of the inductor L1 and the diode D1 is electrically connected to the output terminal on the high potential side of the rectifier circuit 15 connected. Further, a series connection of the switching element Q1 and the resistor R1 is between the output terminal of the rectifier circuit 15 connected via the inductor L1. Further, the smoothing capacitor C1 is connected between the output terminals of the step-up chopper circuit 16 connected. The turning on and off of the switching element Q1 generates a boosting voltage on 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, for example, an n-channel enhancement MOSFET (Field Effect Transistor). In the step-down chopper circuit 17 are between the output terminals of the step-up chopper circuit 16 (between both ends of the smoothing capacitor C1), the switching element Q2, the inductor L2, the smoothing capacitor C2 and the resistor R2 are electrically connected in series with each other in this order. A series connection 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 the two ends of the smoothing capacitor C1). Further, a series connection of the inductor L2 and the smoothing capacitor C2 is electrically connected between the anode and the cathode of the diode D2. The solid-state light source 3 is electrically connected between both ends of the smoothing capacitor C2.

The smoothing capacitor C2 is electrically parallel to an output, ie, the solid-state light source 3 , the step-down chopper circuit 17 Therefore, the difference between a peak value and a lower value of an output current Io is decreased, and the waveform of the output current Io approaches a DC waveform including a few current ripples. At this time, a voltage across the smoothing capacitor C2 is substantially equal to a forward voltage of the solid-state light source 3 , In the present embodiment, the output current Io is equal to the sum of the first current I1, which is a forward current of the solid-state light source 3 and a second current I2 passing through the constant current circuit 12 flows. The forward voltage of the solid-state light source 3 becomes according to forward current forward voltage characteristics of the solid-state light source 3 and determined according to the dimming ratio.

The constant current circuit 12 is electrically parallel to the solid-state light source 3 connected. The constant current circuit 12 includes two resistors R3 and R4 and a switching element Q3. Between the two ends of the smoothing capacitor C2 of the step-down chopper circuit 17 For example, the resistor R4, the switching element Q3 and the resistor R3 are electrically connected in series in this order. The resistor R4 is connected to a high potential side of the step-down chopper circuit 17 connected, and the resistor R3 is connected to a side of low potential of the step-down chopper circuit 17 connected. Specifically, the resistor R4 is electrically connected to an output terminal on the high potential side of the step-down chopper circuit 17 and the resistor R3 is electrically connected to a low potential side output terminal of the step-down chopper circuit 17 connected. The switching element Q3 is, for example, an n-channel enhancement MOSFET (Field Effect Transistor). The switching element Q3 operates in a linear region (active region) in response to a constant current control signal S3, which will be described later. In other words, the switching element Q3 increases and decreases a drain current, which is the second current I2 flowing through the constant current circuit 12 flows in response to the constant current control signal S3. According to the indicated value of the constant current control signal S3, the magnitude of the second current I2 flowing through the constant current circuit becomes 12 flows, set.

The control circuit 13 is formed to the feed circuit 11 and the constant current circuit 12 to control the solid-state light source 3 to cause light to emit in an amount according to the dimming ratio. The control circuit 13 includes a boost control circuit 131 , a controller 132 , a voltage reduction control circuit 133 and a constant current control circuit 134 , The control circuit 13 controls the feed circuit 11 and the constant current circuit 12 by the method of continuous dimming independent of the dimming ratio.

A dimming signal S1 from the outside in the control circuit 13 is a pulse width modulation (PWM) signal which is a duty ratio (ratio of a turn-on period to a cycle) which is variable according to the dimming ratio. The control circuit 13 receives the dimming signal S1 from an external device, such as a controller, for example, dimming console called. The dimming signal S1 may be a signal of a standardized communication protocol, such as DMX512. Alternatively, the dimming signal S1 may be a signal that satisfies a wired communication scheme, such as Universal Asynchronous Transmitter (UART).

The boost control circuit 131 is configured to perform a switching control of turning on and off the switching element Q1 to the step-up chopper voltage boosting operation 16 to control. Specifically, the voltage boost control circuit 131 configured to detect a voltage across the resistor R1 and to control the duty cycle of the switching element Q1 such that the voltage across the smoothing capacitor C1 is constant. The boost control circuit 131 compares a current detected by a current detector (not shown) and flowing through the inductor L1 with a threshold value to determine a turn-on timing of the switching element Q1. Further, the boosting control circuit compares 131 the voltage across the resistor R1 (a current flowing through the switching element Q1) with the threshold value to determine a turn-off timing of the switching element Q1. The boost control circuit 131 sets the on-time and the off-time of the switching element Q1 to control a boost voltage generated on the smoothing capacitor C1 to be a predetermined voltage.

The control 132 includes a microcontroller including a processor, such as a central processing unit (CPU), and a memory. The control 132 is configured such that a program stored in the memory is executed by the processor (CPU) to perform the step-down chopper circuit 17 to dim the light coming from the solid-state light source 3 is broadcast. The control 132e externally receives the dimming signal S1 and works to increase the brightness of the light coming from the solid state light source 3 is emitted to match the brightness required by the dimming signal S1.

The control 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 with increasing duty cycle of the dimming signal S1. Specifically, when the dimming signal S1 has a duty ratio of 0% to 5%, the dimming ratio is 100% (full illumination), while if the dimming signal S1 has a duty ratio of 95% to 100%, the dimming ratio is 0% (light is off ). When the dimming signal S1 has a duty ratio of 5% to 95%, the dimming ratio decreases as the duty ratio of the dimming signal S1 increases. The ratio described above (the ratio between the duty cycle of the dimming signal S1 and the dimming ratio), that in the controller 132 is not limited to the dimming table, but may be a function.

When the dimming signal S1 is received from the outside, the control refers 132 to the dimming table to determine a dimming ratio according to the duty ratio of the dimming signal S1. The control 132 generates a voltage reduction control signal S2 in accordance with the determined dimming ratio and outputs the voltage reduction control signal S2 to the voltage reduction control circuit 133 out. The voltage reduction control signal S2 is a signal indicating the dimming ratio.

The voltage reduction control circuit 133 performs the switching control of turning on and off the switching element Q2 of the step-down chopper circuit 17 on the basis of the voltage reduction control signal S2 by the voltage reduction operation of the step-down chopper circuit 17 to control. Specifically, the voltage reduction control circuit compares 133 a current, which is detected by a current detector (not shown) and flows through the inductor L2, with the threshold value to determine a turn-on time of the switching element Q2. Further, the voltage reduction control circuit compares 133 a voltage across the resistor R2 (a current flowing through the switching element Q2) with the threshold value to determine a turn-off timing of the switching element Q2. That is, the voltage reduction control circuit 133 sets the on time and the off time of the switching element Q2 in accordance with the dimming ratio indicated by the voltage reduction control signal S2. Thus, the voltage reduction control circuit controls 133 the step-down chopper circuit 17 such that the current (output current Io) passing through the solid state light source 3 flows, having a current value according to the dimming ratio.

Here controls at the control circuit 13 at least when the dimming ratio is less than the threshold, the controller 132 the feeding circuit 11 to the feed circuit 11 to continuously output the output current Io which is larger than the first current I1. Further, at least when the dimming ratio is smaller than the threshold, the controller controls 132 the constant current circuit 12 to the second stream I2, which is a difference between the output current Io and the first current I1, continuously through the constant current circuit 12 to flow, the second current I2 is maintained to have a prescribed value. Here, "when the dimming ratio is smaller than the threshold value" means the case where the dimming ratio is larger than 0% and smaller than the threshold value.

At the control circuit 13 The first embodiment controls the controller 132 the feeding circuit 11 to the feed circuit 11 to continuously output the output current Io which is larger than the first current I1, and controls the constant current circuit 12 to allow the second current I2, continuously through the constant current circuit 12 to flow, regardless of the size of the dimming ratio. That is, when the dimming ratio is smaller than the threshold, the feeding circuit gives 11 continuously the output current 10 which has a larger current value than the first current I1, and the second current I2 whose current value is a constant value flows continuously through the constant current circuit 12 ,

At least when the dimming ratio determined according to the dimming signal S1 is smaller than the threshold value, the controller gives 132 a constant current control signal S3 to the constant current control circuit 134 out. In the first embodiment, the controller gives 132 the constant current control signal S3 to the constant current control circuit 134 regardless of the value of the dimming ratio determined in accordance with the dimming signal S1. In other words, the controller gives 132 the constant current control signal S3 to the constant current control circuit 134 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 indicating the magnitude (current value) of the second current 12 indicates which by the constant current circuit 12 will flow. The constant current control signal S3 of the first embodiment is, for example, a PWM signal having a constant duty ratio regardless of the dimming ratio. That is, the second current I2 flowing through the constant current circuit 12 flows has 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 be in the linear range by using the constant current control signal S3 from the controller 132 to work. The constant current control circuit 134 adjusts the voltage value of a gate-source voltage of the switching element Q3 such that the second current I2 generated by the constant-current circuit 12 flow, has a constant value.

In the first embodiment, the control circuit includes 13 a computer including a processor and a memory, and stores a program to make the computer perform the above-described function.

Next, the lighting device 1 according to the first embodiment 2 described.

Initially, the controller refers 132 the control circuit 13 when receiving the dimming signal S1 indicating a certain dimming ratio, to the dimming table to determine a dimming ratio according to the duty ratio of the dimming signal S1. Then put the controller 132 the output current Io coming from the step-down chopper circuit 17 is output such that the first current I1 passing through the solid-state light source 3 flows, having a current value corresponding to the dimming ratio. That is, as in 2 is shown, gives the controller 132 the voltage reduction control signal S2 to the voltage reduction control circuit 133 such that the output current Io is the sum of the first current I1 passing through the solid-state light source 3 and the second current I2 flowing through the constant current circuit 12 flows, is.

For example, it is assumed that the first current I1 is responsible for full illumination of the solid state light source 3 is required, 500 mA is (in 2 , 100%), and the second current I2 passing through the constant current circuit 12 flows, 50 mA is (in 2 , 10%). For a full illumination (dimming ratio 100%) of the solid-state light source 3 to reach, gives the controller 132 the voltage reduction control signal S2 to the voltage reduction control circuit 133 such that the output current Io is 550 mA (in 2 , 110%). To the first current I1 to the solid-state light source 3 to set to 50 mA (10% of the current in the case of full illumination), gives the control 132 the voltage reduction control signal S2 to the voltage reduction control circuit 133 such that the output current Io is 100 mA (in 2 , 20%).

The voltage reduction control circuit 133 sets the on time and the off time of the switching element Q2 based on the voltage reduction control signal S2. This controls the step-down chopper circuit 17 the output current Io so as to have a current value corresponding to the determined dimming ratio, and to output the output current Io the solid-state light source 3 and the constant current circuit 12 out.

Further, the controller gives 132 when receiving the dimming signal S1, the constant current control signal S3 to the constant current control circuit 134 such that the second current I2, which has a constant value, through the constant current circuit 12 flows. 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. Thereby, the second current I2 having the constant value flows through the constant current circuit 12 ,

According to the previous description, the first current I1 flowing by subtracting the second current I2 flowing through the constant current circuit flows 12 flows from the output current Io of the step-down chopper circuit 17 is obtained by the solid-state light source 3 , That is, the first current I1 according to the dimming ratio flows through the solid-state light source 3 , Thus, the solid-state light source 3 be illuminated with a brightness according to the dimming ratio.

The lighting device 1 According to the first embodiment described above, the feeding circuit includes 11 , the constant current circuit 12 and the control circuit 13 , The feeding circuit 11 is formed around the first current I1 according to the dimming ratio of the solid-state light source 3 feed to the solid state light source 3 to cause light to emit in an amount according to the dimming ratio. The constant current circuit 12 is electrically parallel to the solid-state light source 3 connected. The control circuit 13 is formed to the feed circuit 11 and the constant current circuit 12 to control the solid-state light source 3 to cause light to emit in the amount according to the dimming ratio. At least when the dimming ratio is less than the threshold, the control circuit controls 13 the feeding circuit 11 to the feed circuit 11 to continuously output the output current Io which is larger than the first current I1. Further, at least when the dimming ratio is smaller than the threshold, the control circuit controls 13 the constant current circuit 12 to allow the second current I2, which is a difference between the output current Io and the first current I1, continuously through the constant current circuit 12 to flow.

At least when the dimming ratio is smaller than the threshold, the lighting device controls 1 according to the first embodiment, the feeding circuit 11 to the feed circuit 11 to make output the output current Io which is larger than the first current I1, that of the solid-state light source 3 is supplied. Further, at least when the dimming ratio is smaller than the threshold, the lighting device controls 1 the constant current circuit 12 to enable the second current I2, which is the difference between the output current Io and the first current I1, through the constant current circuit 12 to flow. This allows the lighting device 1 According to the first embodiment, a reduction in the flicker of a light emitted from the solid-state light source 3 is output compared to the case of burst dimming even when the dimming ratio is relatively low, such as in the case of fade-in or fade-out operation. Consequently, it is possible the light coming from the solid-state light source 3 is spent gently changing. That is, the lighting device 1 According to the first embodiment, it is possible to improve the fade-in and fade-out performance at the time of the fade-in or fade-out operation.

Further, when a method for continuous dimming as a dimming method of the solid-state light source 3 through the lighting device 1 is used, a capacitor with a small capacitance may be used as the smoothing capacitor C2, in contrast to a burst dimming method. More specifically, the burst dimming method requires a large-capacitance capacitor as a smoothing capacitor as a countermeasure to video flicker. In contrast, the present embodiment uses the method of continuous dimming, and thus does not require a large-capacity capacitor as the smoothing capacitor C2, but a capacitor with a small capacitance is sufficient as a countermeasure. Thus, it is possible to reduce the charging time of the smoothing capacitor C2. Consequently, the output current Io and the first current I1 can be set to the current value according to the dimming ratio in a short period of time. Thus, at the time of fade-in or fade-out operation, the light coming from the solid-state light source 3 is issued, be changed more gently.

In the lighting device 1 According to the first embodiment, the second current I2 preferably has a constant value independent of the dimming ratio. The control circuit 13 preferably controls the feed circuit 11 to the feed circuit 11 to bring continuously the output current 10 output larger than the first current I1, and preferably controls the constant current circuit 12 to allow the second current I2, continuously through the constant current circuit 12 regardless of the strength of the dimming ratio.

In the lighting device 1 according to the first embodiment includes the Constant current circuit 12 preferably the switching element Q3. The switching element Q3 is electrically connected to the output terminal of the supply circuit 11 connected. 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 includes 12 preferably a resistive element (resistor R4). The resistive element is electrically connected in series with the switching element Q3.

In the lighting device 1 according to the first embodiment in the constant current circuit 12 For example, the switching element Q3 and the resistive element (the resistor R4) are electrically connected in series. This can reduce the voltage applied to the switching element Q3, and therefore, the loss on the switching element Q3 can be reduced.

In the lighting device 1 According to the first embodiment, the switching element Q3 is preferably electrically connected to the output terminal of the supply circuit 11 connected to allow the second current I2 to flow through the switching element Q3.

Further operates in the lighting device 1 According to the first embodiment, the control circuit 13 Preferably, the switching element Q3 in the linear region to change the strength of the second current I2.

Further controls in the lighting device 1 According to the first embodiment, the control circuit 13 preferably the feed circuit 11 and the constant current circuit 12 by the method of continuous dimming independent of the dimming ratio. The continuous dimming method is a method of changing the magnitude of the first current I1 that is continuous with the solid-state light source 3 is supplied.

The program according to the first embodiment is a program to the computer operating in the control circuit 13 the lighting device 1 to bring to realize the following function. The function is a function for, at least when the dimming ratio is smaller than the threshold, the feed circuit 11 to control the feed circuit 11 to continuously output the output current Io larger than the first current I1 and the constant current circuit 12 to control the second current I2, which is the difference between the output current Io and the first current I1, continuously through the constant current circuit 12 to flow.

Second Embodiment

A lighting device 1 according to a second embodiment differs from the lighting device 1 according to the first embodiment in that a second current I2 only by a constant current circuit 12 flows when a dimming ratio is less than a threshold value. The same components as those of the lighting device 1 according to the first embodiment are indicated by the same reference numerals and the description thereof will be omitted.

A control circuit 13 The second embodiment controls the constant current circuit 12 to allow the second current I2, only by the constant current circuit 12 to flow when the dimming ratio is less than the threshold. The description of functions similar to those of the control circuit 13 of the first embodiment will be omitted.

In particular, when the dimming ratio is greater than or equal to the threshold value, the control circuit controls 13 a feed circuit 11 such that the magnitude of an output current Io corresponds to the magnitude of a first current I1, and controls the constant current circuit 12 to prevent the second current I2 through the constant current circuit 12 flows, while when the dimming ratio is smaller than the threshold, the control circuit 13 the feeding circuit 11 such that the output current Io is greater than the first current I1, and the constant current circuit 12 in order to enable the second current I2, continuously through the constant current circuit 12 to flow.

A controller 132 of the second embodiment outputs a constant current control signal S3 to a constant current control circuit 134 only off if the dimming ratio is less than the threshold value. The control 132 The second embodiment stores a dimming table representing 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. Specifically, the dimming table defines the ratio between the second current I2 and the dimming ratio such that the second current I2 is 0 when the dimming ratio is greater than or is equal to the threshold value, and that the current value of the second current I2 increases with decreasing dimming ratio when the dimming ratio is smaller than the threshold value.

The control circuit 13 In the second embodiment, by using the dimming table, the constant current circuit is controlled 12 to increase the second current I2 as the dimming ratio decreases, when the dimming ratio is less than the threshold.

Next, the operation of the lighting device 1 according to the second embodiment 3 described. The threshold is defined as a dimming ratio for the case where the first current I1 is 50 mA (10% of the current in the case of full illumination).

First, the controller determines 132 the control circuit 13 when receiving a dimming signal S1 indicating a certain dimming ratio, the dimming ratio according to the duty ratio of the dimming signal S1 with respect to the dimming table. Then put the controller 132 the output current Io coming from a step-down chopper circuit 17 is output such that the first current I1 passing through a solid state light source 3 flows, having a current value corresponding to the dimming ratio. That is, as in 3 is shown, if the dimming ratio is greater than or equal to the threshold, the controller gives 132 the voltage reduction control signal S2 so to a voltage reduction control circuit 133 from that the output current Io is the sum of the first current I1 passing through the solid state light source 3 and the second current I2 flowing through the constant current circuit 12 flows, is. On the other hand, when the dimming ratio is smaller than the threshold value, the second current I2 does not flow through the constant current circuit 12 and therefore gives the controller 132 the voltage reduction control signal S2 so to the voltage reduction control circuit 133 in that the output current Io corresponds to the first current I1 passing through the solid-state light source 3 flows.

The voltage reduction control circuit 133 sets the on-time and the off-time of a switching element Q2 based on the voltage reduction control signal S2. Thus, the step-down chopper circuit controls 17 the output current 10 such that it has a current value corresponding to the determined dimming ratio, and outputs the output current Io to the solid-state light source 3 and the constant current circuit 12 out.

Further, when the dimming signal S1 is received, as in FIG 3 is shown, gives the controller 132 the constant current control signal S3 to the constant current control circuit 134 from that the second current I2 only by the constant current circuit 12 flows when the dimming ratio is smaller than the threshold value. The constant current control circuit 134 controls a switching element Q3 to operate in a linear region based on the constant current control signal S3. Thus, the second current I2 having a constant value flows through the constant current circuit 12 , On the other hand, if the dimming ratio is greater than or equal to the threshold value, the controller gives 132 the constant current control signal S3 does not go to the constant current control circuit 134 out. The switching element Q3 remains in the off state and the second current I2 does not flow through the constant current circuit 12 ,

According to the above-described, when the dimming ratio is greater than or equal to the threshold value, the output current Io of the step-down chopper circuit flows 17 through the solid-state light source 3 as the first current I1. On the other hand, when the dimming ratio is smaller than the threshold value, the first current I1 flowing by subtracting the second current I2 flowing through the constant current circuit flows 12 flows from the output current Io of the step-down chopper circuit 17 , is obtained by the solid-state light source 3 , In both cases, the first current I1 flows through the solid-state light source according to the dimming ratio 3 , Thus, the solid-state light source 3 be illuminated in a brightness according to the dimming ratio.

For example, it is assumed that the first current I1, the full illumination of the solid-state light source 3 is required, 500 mA is (in 3 , 100%), and the second current I2 passing through the constant current circuit 12 flows, 50 mA is (in 3 , 10%). For a full illumination (dimming ratio 100%) of the solid-state light source 3 to reach, gives the controller 132 the voltage reduction control signal S2 so to the voltage reduction control circuit 133 that the output current Io is 500 mA (in 3 , 100%). To the first current I1 to the solid-state light source 3 to set so that it is less than 50 mA (10% of the current in the case of full illumination), gives the controller 132 the voltage reduction control signal S2 so to the voltage reduction control circuit 133 that the output current Io is 50 mA (in 3 , 10%), and gives the control 132 the constant current control signal S3 to the constant current control circuit 134 out.

Also, in the second embodiment, similarly to the first embodiment, the control circuit includes 13 a computer that includes a processor and memory. The control circuit 13 In the second embodiment, a program stores the computer to perform functions described in the first embodiment and the second embodiment.

In the lighting device 1 According to the second embodiment described above, when the dimming ratio is greater than or equal to the threshold value, the control circuit controls 13 preferably the feed circuit 11 such that the magnitude of the output current Io corresponds to the magnitude of the first current I1. Further, at least when the dimming ratio is greater than or equal to the threshold, the control circuit controls 13 preferably the constant current circuit 12 to prevent the second current I2 through the constant current circuit 12 flows. If the dimming ratio is less than the threshold, the control circuit controls 13 preferably the feed circuit 11 such that the output current Io is greater than the first current I1. Further, when the dimming ratio is smaller than the threshold value, the control circuit controls 13 preferably the constant current circuit 12 to allow the second current I2, continuously through the constant current circuit 12 to flow.

Further, the control circuit controls 13 preferably in the lighting device 1 According to the second embodiment, when the dimming ratio is smaller than the threshold, the feeding circuit 11 such that the value of the output current Io is constant regardless of the dimming ratio. Further, when the dimming ratio is smaller than the threshold value, the control circuit controls 13 preferably the constant current circuit 12 to increase the second current I2 as the dimming ratio decreases.

Third Embodiment

In terms of 4 becomes a lighting fixture 4 according to a third embodiment described below. The lighting fixture 4 According to the third embodiment, a so-called horizontal light used to form a background wall surface (horizontal surface) of a studio of a television station, a stage o. Ä. to illuminate.

As in 4 is shown, includes the lighting fixture 4 According to the third embodiment, a light source unit 5 as a solid-state light source and a power supply unit 6 , The lighting fixture 4 According to the third embodiment will be described below, where the forward and backward directions, the right and left directions and the upward and downward directions as in 4 are defined shown. That is, in the plane of the sheet of 4 For example, the left side is defined as the front side, and the right side is defined as the rear side, and in the plane of the sheet of 4 For example, the upper side is defined as the left side, and the lower side is defined as the right side.

The light source unit 5 includes four light emitting diode (LED) modules 50 , a first body 51 , a reflection block 52 and a heat dissipation block 53 , Each LED module 50 includes solid state light emitting elements mounted on a surface of a rectangular substrate.

The first body 51 consists of a metal plate to have a rectangular cuboid shape. The first body 51 has a front surface in which a rectangular window hole 510 is open. In the first body 51 are the four LED modules 50 arranged in two rows and two columns, with surfaces of the LED modules 50 the window hole 510 are opposite.

The reflection block 52 includes reflectors 520 and a sign 521 , The reflectors 520 and the sign 521 are between the window hole 510 and the surfaces of the LED modules 50 in the first body 51 are arranged and are adapted to the alignment of the light coming from the LED modules 50 is broadcast, control.

The heat-dissipating block 53 includes heat sink 530 , The heat sink 530 are lined up at regular intervals to each other along a direction of the thickness of the heat sink. The heat-dissipating block 53 is on a back surface of the first body 51 arranged. The heat-dissipating block 53 is preferably thermal with each (of substrates) of the four LED modules 50 in the first body 51 connected.

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 ; a second body 60 that receives the circuit block; and a pair of arms 61 , The circuit block is the lighting device 1 the first or second embodiment.

The second body 60 consists of a metal plate to have a flat rectangular cuboid shape to accommodate the circuit block. The poor 61 in the pair are at respective right and left ends of the second body 60 provided and stick up. Each of the pair of arms 61 has a width in the forward and backward directions, the width narrows successively toward the tip end (upper end) of the arm. Every arm 61 has an insertion hole formed in its tip portion and a bolt of a so-called stud bolt 62 is to be inserted into the through hole. That is, the pair of arms 61 rotatably supports the light source unit 5 by bolts inserted into the insertion hole in the Tip section in female screws, which are on both right and left sides of the first body 51 provided are introduced.

Next, a used condition of the lighting fixture 4 according to the third embodiment will be described. The lighting fixture 4 According to the third embodiment, for example, it is installed on a floor at a distance to the background wall surface with the window hole 510 the light source unit 5 the background wall surface is opposite. The lighting fixture 4 According to the third embodiment, substantially uniform irradiation of the background wall surface from its lower portion to its upper portion with illuminating light is enabled.

The lighting fixture 4 According to the third embodiment described above, the lighting device includes 1 and the solid-state light source (light source unit 5 ).

Also controls the lighting fixture 4 According to the third embodiment, at least when the dimming ratio is smaller than the threshold, the control circuit 13 the lighting device 1 the feeding circuit 11 to the feed circuit 11 to make output an output current Io which is larger than a first current I1 corresponding to the solid-state light source (light source unit 5 ) is supplied. Further, at least when the dimming ratio is smaller than the threshold, the control circuit controls 13 the lighting device 1 the constant current circuit 12 to enable a second current I2, which is a difference between the output current Io and the first current I1, through the constant current circuit 12 to flow. This allows the lighting fixture 4 Also, according to the third embodiment, a reduction in the flicker of a light output from the solid-state light source, as compared with the case of burst dimming, even if the dimming ratio is relatively low, as in the case of the fade-in or fade-out operation, similar to in the first embodiment. Consequently, it is possible to smoothly change the light output from the solid-state light source.

The lighting fixture 4 is not on the solid-state light source (light source unit 5 ) of the monochromatic light, but as a variation of the third embodiment, the lighting fixture 4 a solid-state light source (light source unit) which emits colored light. In this case, the lighting fixture includes 4 as solid-state light emitting elements of the solid-state light source, for example, a solid-state light emitting element emitting red light, a solid-state light emitting element emitting green light, and a solid-state light emitting element emitting blue light. Furthermore, the lighting fixture 4 include a solid state light emitting element that emits white light.

Furthermore, the lighting fixture 4 not limited to the horizontal light, but may be a lighting fixture used in another application.

Fourth Embodiment

In terms of 5 becomes a lighting system 7 according to a fourth embodiment will be described below. As in 5 is shown, includes the lighting system 7 according to the fourth embodiment, lighting fixture 4 and a dimming control panel 8th as a controller. The lighting fixtures 4 are through a feedthrough connection with the dimming control panel 8th via a communication cable 80 connected. The dimming control panel 8th transmits a dimming signal S1 of a standardized communication protocol, such as DMX512, over the communication cable 80 to the lighting fixtures 4 , The lighting fixtures 4 receive the dimming signal S1 from the dimming control panel 8th is transmitted via control circuits 13 , and the control circuits 13 control the step-down chopper circuits 17 and the constant current circuits 12 ,

The lighting system 7 According to the fourth embodiment described above, the lighting fixtures include 4 and the controller (the dimming control panel 8th ). The controller transmits a dimming signal indicating a dimming ratio to the lighting fixtures 4 ,

Also controls in the lighting system 7 According to the fourth embodiment, at least when the dimming ratio is smaller than a threshold, the control circuit 13 the lighting device 1 a feed circuit 11 to the feed circuit 11 to cause to output an output current Io greater than a first current I1 of a solid state light source 3 is supplied. Further, at least when the dimming ratio is less than a threshold, the control circuit controls 13 the lighting device 1 the constant current circuit 12 to enable a second current I2, which is a difference between the output current Io and the first current I1, through the constant current circuit 12 to flow. This allows the lighting system 7 According to the fourth embodiment, a reduction in the flicker of a light emitted from the solid-state light source 3 is output compared with the case of burst dimming even if the dimming ratio is relatively low, as in the case of the Fade or fade-out operation similar to the first embodiment. Consequently, it is possible the light coming from the solid-state light source 3 is spent gently changing.

The lighting device 1 in each of the embodiments includes a computer. The computer executes a program to perform the function of the lighting device 1 to realize in each embodiment. The computer includes a processor which operates according to the program as a master hardware configuration. As long as the processor can execute the program to the function of the lighting device 1 Any type of processor can be used. The processor includes one or more electronic circuits including integrated circuit (IC) or large scale integration (LSI). The electronic circuits may be integrated on a chip or may be provided on chips. The chips can be collected on a device or devices can be provided. The program is stored in a nonvolatile storage medium such as a read only memory (ROM), an optical disk or a hard disk. The non-volatile storage medium is a computer-readable storage medium and stores the program non-volatile. The program may be stored in advance in the nonvolatile storage medium or may be supplied to the nonvolatile storage medium via a wide area communication network, such as the Internet.

The aforementioned first to fourth embodiments are some of several embodiments according to the present invention. In addition, the foregoing first to fourth embodiments may be implemented in various ways according to the configuration or the like. as long as they can achieve the objective of the present invention.

LIST OF REFERENCE NUMBERS

1

lighting device

11

feeder circuit

12

Constant current circuit

13

control circuit

3

Solid state light source

4

lighting

7

lighting system

8th

Dimming control panel (control)

I1

First stream

I2

Second stream

io

output current

Q3

switching element

R4

Resistance (resistant element)

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2015-225825 A [0002]

Claims (12)

Lighting device ( 1 ) comprising: a feed circuit ( 11 ) configured to generate a first current (I1) in accordance with a dimming ratio of a solid-state light source ( 3 ) to the solid state light source ( 3 ) to emit light in an amount according to the dimming ratio; a constant current circuit ( 12 ) parallel to the solid-state light source ( 3 ) is switched; and a control circuit ( 13 ) which is adapted to the feed circuit ( 11 ) and the constant current circuit ( 12 ) to control the solid state light source ( 3 ) to emit light in the amount in accordance with the dimming ratio, wherein, at least if the dimming ratio is less than a threshold value, the control circuit ( 13 ) the feed circuit ( 11 ) controls the feed circuit ( 11 ) to output continuously an output current (Io) greater than the first current (I1), and the constant current circuit ( 12 ) to enable a second current (I2), which is a difference between the output current (Io) and the first current (I1), to be continuously passed through the constant current circuit (12). 12 ) to flow. Lighting device ( 1 ) according to claim 1, wherein the second current (I2) has a constant value independent of the dimming ratio, and the control circuit (12) 13 ) the feed circuit ( 11 ) controls the feed circuit ( 11 ) to output continuously the output current (Io) larger than the first current (I1) and the constant current circuit ( 12 ) to allow the second current (I2) to be continuously controlled by the constant current circuit ( 12 ) regardless of the dimming ratio. Lighting device ( 1 ) according to claim 1, wherein, when the dimming ratio is greater than or less than the threshold, the control circuit (16) 13 ) the feed circuit ( 11 ) such that a magnitude of the output current (Io) is equal to a magnitude of the first current (I1), and the constant current circuit ( 12 ) to prevent the second current (I2) from being controlled by the constant current circuit ( 12 ), while if the dimming ratio is less than the threshold value, the control circuit ( 13 ) the feed circuit ( 11 ) controls so that the output current (Io) is greater than the first current (I1), and the constant current circuit ( 12 ) to allow the second current (I2) to be continuously controlled by the constant current circuit ( 12 ) to flow. Lighting device ( 1 ) according to claim 3, wherein, if the dimming ratio is smaller than the threshold value, the control circuit ( 13 ) the feed circuit ( 11 ) such that a value of the output current (Io) is constant irrespective of the dimming ratio, and the constant current circuit ( 12 ) to increase the second current (I2) as the dimming ratio decreases. Lighting device ( 1 ) according to one of claims 1 to 4, wherein the constant current circuit ( 12 ) includes a switching element (Q3) electrically connected to an output terminal of the supply circuit (Q3). 11 ), and the control circuit ( 13 ) controls the switching element (Q3) to change a magnitude of the second current (I2). Lighting device ( 1 ) according to claim 5, wherein the constant current circuit ( 12 ) includes a resistive element connected in series with the switching element (Q3). Lighting device ( 1 ) according to claim 5 or 6, wherein the switching element (Q3) is electrically connected to the output terminal of the supply circuit (Q3). 11 ) to allow the second current (I2) to flow through the switching element (Q3). Lighting device ( 1 ) according to one of claims 5 to 7, wherein the control circuit ( 13 ) operates the switching element (Q3) in a linear range to change the magnitude of the second current (I2). Lighting device ( 1 ) according to one of claims 1 to 8, wherein the control circuit ( 13 ) the feed circuit ( 11 ) and the constant current circuit ( 12 by a method for continuous dimming for changing a strength of the first current (I1), which is continuously the solid-state light source ( 3 ), regardless of the dimming ratio. Lighting fixture ( 4 ) comprising: the lighting device ( 1 ) according to any one of claims 1 to 9; and the solid-state light source ( 3 ). Lighting system ( 7 ) comprising: a plurality of lighting fixtures ( 4 ) according to claim 10; and a controller configured to apply a dimming signal indicative of the dimming ratio to the lighting fixtures ( 4 ) transferred to. Program that has a computer running in the control circuit ( 13 ) of the lighting device ( 1 ) according to any one of claims 1 to 9 at least when the dimming ratio is smaller than the threshold value, brings about a function for controlling the feeding circuit (FIG. 11 ) to realize the feed circuit ( 11 ) to continuously output the output current (Io) larger than the first current (I1) and to control the constant current circuit (Io) 12 ) to enable the second current (I2), which is a difference between the output current (Io) and the first current (I1), to be continuously passed through the constant current circuit (I2). 12 ) to flow.

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