JP2011029054A - Discharge lamp-lighting device and illumination fixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp-lighting device and an illumination fixture using the discharge lamp-lighting device, wherein it is not necessary to cause a stand-by preheat current to flow in a filament when the discharge lamp is turned off, and moreover the lamp is instantly lighted when lighting, and furthermore, an excess stress is not given to an inverter switch and a short period blinking life of the discharge lamp is not impaired. <P>SOLUTION: The discharge lamp-lighting device 1 includes: a DC power source 19; an inverter circuit 11 to convert a DC voltage to a high frequency voltage; an inverter control circuit 22 in order to control an operation frequency of the inverter circuit 11; and a preheating circuit 13 in order to supply a foregoing preheating current to the electrodes of the discharge lamp La. The foregoing preheating time is set by the inverter control circuit 22 so that the area ratio of current×time of the foregoing preheating current concerning the minimum rated voltage and the maximum rated voltage out of a plurality of rated power supply voltage becomes 1:1.2 to 1.6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a discharge lamp lighting device that preheats an electrode before lighting a hot cathode discharge lamp, and a lighting fixture using the discharge lamp lighting device.

  Conventionally, when a hot cathode discharge lamp such as a fluorescent lamp (hereinafter referred to as a discharge lamp) is lit, a current sufficient to discharge thermoelectrons from the filament is applied before applying a starting voltage to both ends thereof. The stress at the time of flashing is suppressed and the short life is avoided. However, the pre-heating time for performing the pre-heating of the filament is generally set to about 1 to 1.5 seconds, and a certain time is required until lighting. When the lamp is turned on at the same time as turning on the power like a light bulb, the filament deteriorates and the life is likely to be shortened.

  As a conventional example in which filament pre-heating is performed, a dimming discharge lamp lighting device disclosed in Patent Document 1 is known. In this conventional example, when a turn-off signal is input from the dimmer to the discharge lamp lighting device, the voltage applied to the discharge lamp becomes a turn-off frequency at which the voltage is lower than the lighting maintenance voltage, and then the standby capable of turning on the discharge lamp immediately. A preheating state is set, and a transition is made to a standby preheating frequency at which the voltage applied to the discharge lamp does not reach the ignition voltage. Even when the lamp is turned off, an appropriate current is always supplied to the filament to enable immediate lighting.

Japanese Patent Application Laid-Open No. 6-223991

  However, in the above-described conventional example, since a current always flows through the filament even in the standby preheating state, power is consumed by the filament. For this reason, when the standby preheating state is long, useless power consumption increases.

  Further, in the discharge lamp lighting device 100 having the circuit configuration shown in FIG. 10, a current as shown in FIG. 11 flows through the inverter switches Q1 and Q2, and stress is constantly applied to the inverter switches Q1 and Q2.

  Here, the operation of the conventional discharge lamp lighting device 100 shown in FIG. 10 will be briefly described. A discharge lamp lighting device 100 shown in FIG. 1 employs a general boost chopper circuit 10 and a half-bridge type inverter circuit 11. The step-up chopper circuit 10 includes a choke coil L1, a diode D2, a smoothing capacitor C2, and a chopper switch (FET) Q1, and is supplied with a DC voltage obtained by rectifying the AC voltage Vin by the full-wave rectifier circuit 16. . The inverter circuit 11 converts the DC voltage obtained by the step-up chopper circuit 10 into a high frequency voltage and applies it to the discharge lamp La. The inverter circuit 11 includes inverter switches (FETs) Q2 and Q3, and an LC resonance circuit 12, a preheating circuit 13, and a discharge lamp La are connected to the output terminals.

  The inverter switches Q2 and Q3 of the inverter circuit 11 are controlled by the inverter control circuit 20, and the chopper switch Q1 of the boost chopper circuit 10 is controlled by the chopper control circuit 21. The power supply for the inverter control circuit 20 and the chopper control circuit 21 is obtained from the control power supply circuit 17 composed of capacitors C4 and C5, diodes D3 and D4, and a resistor R1 connected in parallel with the inverter switch Q3 during inverter operation. It is done.

  However, depending on the design of the LC resonance circuit 12 and the design of the preheating circuit 13, since the resonance current flowing through the LC resonance circuit 12 is small during the preheating, the drains having the waveform as shown in FIG. Current will flow. This is because when the inverter switch Q2 or Q3 is turned on, the electric charge charged in the capacitor C4 of the control power supply circuit 17 flows to the ON inverter switch side. This also causes electrical or thermal stress on the inverter switches Q2 and Q3.

  A smoothing capacitor C6 is interposed between the power supply line of the inverter control circuit 20 and the chopper control circuit 21 and the ground. The preheating circuit 13 includes a transformer T1 and capacitors C7 to C10, and preheats the filament of the discharge lamp La. Since the lamp current flows after the discharge lamp La is turned on, the resonance current flowing through the LC resonance circuit 12 increases. Therefore, the drain current flowing through the inverter switches Q2 and Q3 of the inverter circuit 11 has a waveform as shown in FIG.

  Originally, it can be said that a drain current waveform having a shape as shown in FIG. Since the resonance current is small during the preheating preheating, the inverter switch Q2 or Q3 is turned on without the electric charge charged to the capacitor C4 being completely discharged by the regenerative current, and the electric charge charged to the capacitor C4 is turned on. To flow.

  As described above, in the conventional discharge lamp lighting device having the circuit configuration shown in FIG. 10, standby preheating like the dimming discharge lamp lighting device disclosed in Patent Document 1 always causes stress on the inverter switches Q2 and Q3. This will cause a failure.

  On the other hand, as a method for turning on the discharge lamp La instantaneously, a method for shortening the preheating time and increasing the preheating current to sufficiently heat the filament in a short period and apply an ignition voltage to the discharge lamp La. There is also.

  FIG. 13 shows the emission start characteristic and emitter evaporation start characteristic of the filament in the relationship between the preceding preheating time and the preceding preheating current of a general fluorescent lamp dedicated for high-frequency lighting. As shown in the figure, if the preheating time is long, the emission can be started even if the preheating current is small. However, the current that the emitter starts to evaporate is also lower than when the preheating time is short.

  Here, the problem is that when the preceding preheating time is shortened (for example, 0.3 to 0.5 seconds), it is longer than the general preceding preheating time (for example, 1.1 to 1.3 seconds). The design width of the preceding preheating current is narrow (A> B). Further, when the power supply voltage of the ballast (not shown) is shared with 100V, 200V, and 242V, the waveform as shown in FIG. 14 is obtained, and the difference between the pre-heating currents at 100V and 242V increases. This is because the power supply of the preheating circuit normally increases as the power supply voltage of the ballast (not shown) increases when the power is turned on, so there is a difference between 100V and 242V until the power supply of the preheating circuit becomes constant. . This is because, as long as a plurality of power supply voltages are used in the same step-up chopper circuit, the time until the target output chopper output VDC varies depends on the power supply voltage. Although it can be improved to some extent depending on the design of the boost chopper circuit (error pump design of VDC detection signal / acceleration of feedback), there is always a difference between Vin = 100V and 242V as long as the same boost chopper circuit is used. As shown in FIG. 15, if the preceding preheating time is about 1 second, the difference is relatively reduced.

  In ballasts (not shown) that have a short pre-heating time and are used from 100V to 242V, there is a difference in the pre-current at 100V and 242V, which exceeds the preheating current design range (B) shown in FIG. As a result, the short flashing life will deteriorate.

  The present invention has been made in view of such circumstances, and it is not necessary to supply a standby preheating current to the filament when the discharge lamp is extinguished, and the lamp is turned on instantaneously when it is lit, and further, without applying a great deal of stress to the inverter switch. An object of the present invention is to provide a discharge lamp lighting device that does not impair the short-term flashing life of the discharge lamp, and a lighting fixture using the discharge lamp lighting device.

  A discharge lamp lighting device according to the present invention includes a DC power supply, an inverter circuit that converts a DC voltage output from the DC power supply into a high-frequency voltage, an inverter control circuit for controlling an operating frequency of the inverter circuit, and a discharge lamp. A preheating circuit for supplying a preheating current to the electrodes of the discharge lamp lighting device, wherein the inverter control circuit has a minimum rated power supply voltage and a maximum rated power supply voltage among a plurality of rated power supply voltages. The preceding preheating time is set so that the area ratio of current x time of the preceding preheating current is 1: 1.2 to 1.6.

  According to the above configuration, the preceding preheating time is set to be short so that the current to time area ratio of the preceding preheating current at a plurality of power supply voltages having different voltage values is 1: 1.2 to 1.6. Even when there are a plurality of power supply voltages, it is possible to provide a discharge lamp lighting device that shortens the preceding preheating time so that it can be said to be immediately lit as long as a person feels, and does not impair the short-term flashing life of the lamp.

  In the above configuration, the preceding preheating current supplied from the preheating circuit increases or decreases depending on the preheating frequency, and the inverter control circuit changes the preceding preheating frequency according to the output voltage of the DC power supply.

  According to the above configuration, since the preheating frequency can be changed according to the rated power supply voltage, the preheating time can be said to be sufficient for immediate lighting as a time perceived by a wider range of rated power supply voltages or chopper circuit design. Thus, it is possible to provide a discharge lamp lighting device that does not impair the short-term flashing life of the lamp.

  Further, in the above configuration, the apparatus further includes a control power supply circuit that includes a capacitor and a diode connected in parallel with the inverter switch that configures the inverter circuit, and supplies operation power for the inverter control circuit to the inverter control circuit. .

  According to the above configuration, the stress application time of the inverter switch during the preceding preheating period can be reduced as much as possible.

  Further, in the above configuration, a human body detection sensor that detects the presence or absence of a human body is further provided, and the inverter control circuit receives the signal from the human body detection sensor and controls the discharge lamp to be turned on, dimmed, or turned off. .

  According to the above-described configuration, it is possible to improve the convenience and safety of immediate lighting by eliminating wasteful power consumption when a person is not detected without using a standby preheating method even in a lighting fixture using a human sensor. .

  The lighting fixture of the present invention includes the discharge lamp lighting device and a discharge lamp whose lighting operation is controlled by the discharge lamp lighting device.

  According to the above configuration, it is possible to light up more quickly than conventional products without impairing the short-term flashing life.

  The present invention does not require a standby preheating current to flow to the filament when the discharge lamp is extinguished, and when the lamp is lit, the lamp is turned on instantaneously, and further, no great stress is applied to the inverter switch. There is no loss.

The figure which shows the circuit structure of the discharge lamp lighting device which concerns on Embodiment 1 of this invention. The figure which shows the waveform of the chopper output VDC when the power supply voltage is set to 100V and the preceding preheating current in the discharge lamp lighting device of FIG. The figure which shows the waveform of the chopper output VDC when the power supply voltage is set to 242 V and the preceding preheating current in the discharge lamp lighting device of FIG. The figure which shows the circuit structure of the discharge lamp lighting device which concerns on Embodiment 2 of this invention. The figure which shows the relationship between the prior | preceding preheating current and inverter operating frequency when the power supply voltage is 100V in the discharge lamp lighting device of FIG. The figure which shows the relationship between the prior | preceding preheating current and inverter operating frequency when the power supply voltage is 242V in the discharge lamp lighting device of FIG. The figure which shows the circuit structure of the discharge lamp lighting device which concerns on Embodiment 3 of this invention. The figure which shows the waveform of the drain current of the inverter switch of an inverter circuit in the prior | preceding preheating period when a capacitor capacity is enlarged in a control power supply circuit The block diagram which shows schematic structure of the illuminating device which concerns on Embodiment 4 of this invention. The figure which shows the circuit structure of the conventional discharge lamp lighting device The figure which shows the electric current which flows into the inverter switch of the discharge lamp lighting device of FIG. Diagram showing ideal drain current waveform during pre-heating The figure which shows the emission start characteristic and emitter evaporation start characteristic of the filament in the relation between the pre-heating time and the pre-heating current of a general fluorescent lamp for high frequency lighting The figure which shows the waveform of the preheating current when the advance preheating time is 0.4 seconds and the power supply voltage of the ballast is 100V, 242V The figure which shows the waveform of the preheating current when the preheating time is 1.2 seconds and the power supply voltage of the ballast is 100V and 242V.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described in detail with reference to the drawings.

(Embodiment 1)
1 is a diagram showing a circuit configuration of a discharge lamp lighting device according to Embodiment 1 of the present invention. 1 that are the same as those in FIG. 10 described above are denoted by the same reference numerals.

  In FIG. 1, the discharge lamp lighting device 1 according to the present embodiment adopts the configuration of a boost chopper circuit 10 and a half-bridge type inverter circuit 11, similarly to the conventional discharge lamp lighting device 100. The step-up chopper circuit 10 and the full-wave rectifier circuit 16 constitute a DC power source 19. An output of the inverter circuit 11 is connected to a load circuit 14 including an LC resonance circuit 12, a preheating circuit 13, and a discharge lamp La. The power supply voltage Vin can be input from 100 V to 242 V, and the chopper output VDC is constant regardless of which voltage is input. The chopper output VDC of the boost chopper circuit 10 serves as a power source for the inverter circuit 11 and the load circuit 14. Accordingly, the preheating current supplied from the preheating circuit 13 to the discharge lamp La also varies depending on the value of the chopper output VDC.

  The chopper operation of the step-up chopper circuit 10 is controlled by the chopper control circuit 21, and the inverter operation of the inverter circuit 11 is controlled by the inverter control circuit 22. The preceding preheating time is set by the inverter control circuit 22. An appropriate preceding preheating current, starting voltage, and rated lighting output power can be applied to the discharge lamp La by changing the inverter frequency of preheating to starting to lighting. The lighting frequency during the preceding preheating period is fixed.

  FIG. 2 is a diagram showing waveforms of the chopper output VDC and the preceding preheating current when the power supply voltage is 100V. FIG. 3 is a diagram showing waveforms of the chopper output VDC and the preceding preheating current when the power supply voltage is 242V. As shown in FIGS. 2 and 3, it can be seen that when the power supply voltage is 100 V, the time until the chopper output VDC becomes constant during the preceding preheating period is longer than when the power supply voltage is 242 V. Since the design of the step-up chopper circuit 10 is the same, the time until the power source voltage is boosted to the chopper output VDC differs depending on the magnitude of the power source voltage. If the power supply voltage is small, it takes unavoidable in a general boost chopper circuit that it takes time for the boosted chopper output to reach the target value.

  The characteristic point of the present embodiment is that the preceding preheating time is such that the current to time area ratio of the preceding preheating current between the power supply voltages Vin = 100V and Vin = 242V is 1: 1.2 to 1.6. Is a short point. This is because the ratio of the preheating current at the start of emission and the preheating current at the start of evaporation of the emitter in the same preheating time of a general hot cathode fluorescent lamp is 1: 1.2 to 1.6. Experimentally, in the high-frequency lighting dedicated fluorescent lamps FHT32 and FHT63, the power supply voltage is 100 V and 242 V, and the flashing life test is performed in a state where the area ratio of current to time of the pre-heating current is 1: 1.4 (“Japanese Industrial Standards”). JIS7617-2 Straight tube fluorescent lamp-Part 2: Performance specifications ", specifications for life and Annex C (Test methods for luminous flux maintenance factor and life) are described) It was possible to satisfy the short flashing life of (no disconnection even after 40,000 times). Here, the preceding preheating frequency is constant regardless of the power supply voltage, and by adjusting the preceding preheating time, the area ratio of the current of the preceding preheating current × time is 1: 1.4 at Vin = 100V and Vin = 242V. It is adjusted so that

  As described above, according to the discharge lamp lighting device 1 of the present embodiment, the area ratio of the current x time of the preceding preheating current at the power supply voltages Vin = 100V and 242V is 1: 1.2 to 1.6. Since the preceding preheating time is set to be short, it is possible to light up more quickly than conventional products without impairing the short flashing life. As a specific example, it has been experimentally obtained that if the preceding preheating time is 0.5 seconds or less, the human eye can feel immediate lighting.

(Embodiment 2)
FIG. 4 is a diagram showing a circuit configuration of a discharge lamp lighting device according to Embodiment 2 of the present invention. 4 that are the same as those in FIGS. 10 and 1 described above are denoted by the same reference numerals. The discharge lamp lighting device 2 of the present embodiment is different from the discharge lamp lighting device 1 of the first embodiment described above in that it includes a chopper output detection circuit 30 that detects the chopper output voltage VDC.

  The chopper output detection circuit 30 has three resistors R5 to R7 connected in series and a capacitor C12 connected in parallel to the resistor R7, and is inserted in parallel on the output side of the boost chopper circuit 10. A detection signal (chopper output) S 1 of the chopper output detection circuit 30 is input to the inverter control circuit 23. The inverter control circuit 23 changes the inverter frequency during the preceding preheating according to the detection signal S1 of the chopper output detection circuit 30. Note that the chopper output detection circuit 30 may also be used as a circuit that is actually used for chopper control.

  FIG. 5 is a diagram showing the relationship between the preceding preheating current and the inverter operating frequency when the power supply voltage is 100V. FIG. 6 is a diagram showing the relationship between the preceding preheating current and the inverter operating frequency when the power supply voltage is 242V. As shown in FIG. 5 and FIG. 6, when Vin = 242V, the pre-heating frequency is constant at 120 kHz immediately after the start of the inverter operation, but at Vin = 100V, from 160 kHz to 120 kHz depending on the chopper output voltage VDC. It has changed to. With this operation, a filament preheating current almost equal to Vin = 242V can be supplied even when the chopper output voltage VDC serving as the power source of the load circuit 14 including the inverter circuit 11 and the preheating circuit 13 is low.

  With the above operation, even if the power supply voltage Vin changes, immediate lighting is possible and a short flashing life can be satisfied. For example, even if an attempt is made to make the filament power consumption when Vin = 100V and Vin = 242V the same by detecting and feeding back the drain current of the inverter switch Q3 corresponding to the power consumed in the inverter circuit 11 during the preceding preheating, In the circuit of the conventional example (FIG. 10), the preceding preheating current has a waveform as shown in FIG. 11, and therefore accurate feedback cannot be performed. Also, if the filament power (or filament current) is fed back so that the power consumed by the filament during the pre-heating is the same, a short flashing life can be satisfied at both Vin = 100V and Vin = 242V. It is necessary to add a feedback circuit, which increases the cost.

  As described above, according to the discharge lamp lighting device 2 of the present embodiment, the preceding preheating frequency is changed according to the detection signal S1 of the chopper output detection circuit 30 that detects the chopper output of the step-up chopper circuit 10. The preheating time is shortened so that the lamp can be said to be immediately lit sufficiently as the time perceived by humans in the wider range of rated power supply voltage or chopper circuit design than in the discharge lamp lighting device 1 of Embodiment 1, and the short-term flashing life of the discharge lamp La is shortened. It is possible to provide a discharge lamp lighting device that does not lose.

(Embodiment 3)
FIG. 7 is a diagram showing a circuit configuration of a discharge lamp lighting device according to Embodiment 3 of the present invention. 7 that are the same as those in FIG. 10 described above are denoted by the same reference numerals. The characteristic feature of the discharge lamp lighting device 3 of the present embodiment is that the control power supply of the chopper control circuit 21 of the step-up chopper circuit 10 and the control power supply of the inverter control circuit 22 of the inverter circuit 11 are connected in parallel with the inverter switch Q3. The control power supply circuit 17 supplies power.

  The capacitor C4 of the control power supply circuit 17 needs a certain capacity of the capacitor in order to supply a sufficient current to the inverter control circuit 22 and the chopper control circuit 21 after the inverter operation. However, as described in the conventional example, when the capacitor capacity is large, the drain currents of the inverter switches Q2 and Q3 of the inverter circuit 11 have waveforms as shown in FIG. 8 during the pre-heating period, which causes stress on the inverter switches Q2 and Q3. . In order to enable immediate lighting, when standby preheating is performed when the lamp is extinguished, stress is always applied to the inverter switches Q2 and Q3. Long-time stress application causes a failure of the inverter switches Q2 and Q3.

  Therefore, in the present embodiment, in the inverter control circuit 22, the preceding preheating time is set to be short so that the ratio of the area of the current of the preheating current × time is 1: 1.4 at the power supply voltages Vin = 100V and 242V. Yes. The discharge lamp La can be turned on immediately by setting the preceding preheating time to about 0.4 seconds.

  As described above, according to the discharge lamp lighting device 3 of the present embodiment, even in the circuit configuration of FIG. 7, the inverter control circuit 22 sets the current pre-current current × time area ratio to the power supply voltage Vin = 100V. Since the preceding preheating time is set to be short so as to be 1: 1.4 at 242 V, the stress application time to the inverter switches Q2 and Q3 of the inverter circuit 11 can be shortened as much as possible, and the short-term flashing life is not impaired. In addition, immediate lighting is possible.

(Embodiment 4)
FIG. 9 is a block diagram showing a schematic configuration of a lighting fixture according to Embodiment 4 of the present invention. The lighting fixture 5 of the present embodiment includes a discharge lamp lighting device 4 having a human sensor 40 such as a pyroelectric sensor that detects the presence or absence of a person using infrared rays. Note that the discharge lamp lighting device 4 includes an input filter circuit 15 in front of the full-wave rectifier circuit 16. This input filter circuit 15 is of course applicable to the discharge lamp lighting devices 1 to 3 of the first to third embodiments described above, and is generally used. The input filter circuit 15, the full wave rectifier circuit 16, and the boost chopper circuit 10 constitute a DC power source 19A.

  In the discharge lamp lighting device 4, when the human sensor 40 detects a person when the lamp is extinguished, an H signal is output to the inverter control circuit 24. When the inverter control circuit 24 detects the H signal, the inverter control circuit 24 appropriately preheats the filament of the discharge lamp La, and then applies a starting voltage to both ends of the lamp to light it.

  In the present embodiment, in the inverter control circuit 24, the preceding preheating time is set short so that the area ratio of current x time of the preceding preheating current is 1: 1.4 at the power supply voltages Vin = 100V and 242V. The discharge lamp La can be turned on immediately by setting the preceding preheating time to about 0.4 seconds. In the conventional discharge lamp lighting device 100 having a pre-heating time of 1 second or more as in the prior art, it is inconvenient in passages and stairs in a dark environment. Since it takes time to turn on after detecting a person, the person walks a few steps or stairs, which may be dangerous.

  Thus, according to the lighting fixture 5 of this Embodiment, since the discharge lamp lighting device 4 has the human sensor 40 and detects the presence or absence of a person, the convenience and safety by immediate lighting improve, and standby Preheating does not have to be performed, and standby power can be reduced when there are no people. Needless to say, even if the power supply voltage changes as in the first to third embodiments, the short-term flashing life is not impaired.

DESCRIPTION OF SYMBOLS 1-4 Discharge lamp lighting device 5 Lighting fixture 10 Boost chopper circuit 11 Inverter circuit 12 LC resonance circuit 13 Preheating circuit 14 Load circuit 15 Input filter circuit 16 Full wave rectifier circuit 17 Control power supply circuit 19, 19A DC power supply 21 Chopper control circuit 22, 23, 24 Inverter control circuit 30 Chopper output detection circuit 40 Human sensor La Discharge lamp

Claims (5)

DC power supply,
An inverter circuit for converting a DC voltage output from the DC power source into a high-frequency voltage;
An inverter control circuit for controlling the operating frequency of the inverter circuit;
A preheating circuit for supplying a preheating current to the electrodes of the discharge lamp;
A discharge lamp lighting device comprising:
The inverter control circuit is preceded so that a current × time area ratio of the preceding preheating current at the minimum rated power supply voltage and the maximum rated power supply voltage among the plurality of rated power supply voltages is 1: 1.2 to 1.6. A discharge lamp lighting device that sets the preheating time.   2. The discharge lamp according to claim 1, wherein the preceding preheating current supplied from the preheating circuit increases or decreases depending on the preheating frequency, and the inverter control circuit changes the preceding preheating frequency according to the output voltage of the DC power supply. Lighting device.   2. The control power supply circuit according to claim 1, further comprising a control power supply circuit that includes a capacitor and a diode connected in parallel with an inverter switch that constitutes the inverter circuit, and supplies a power supply for operating the inverter control circuit to the inverter control circuit. The discharge lamp lighting device according to 2. It further comprises a human body detection sensor for detecting the presence or absence of a human body,
The discharge lamp lighting device according to any one of claims 1 to 3, wherein the inverter control circuit controls the discharge lamp to be turned on, dimmed, or turned off in response to a signal from the human body detection sensor. The discharge lamp lighting device according to any one of claims 1 to 4,
A discharge lamp whose lighting operation is controlled by the discharge lamp lighting device;
Lighting equipment with

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