JP5122788B2 - Discharge lamp lighting device, lighting device and refrigerated showcase - Google Patents

Description

  The present invention relates to a discharge lamp lighting device having a dimming function capable of changing the output of a discharge lamp by switching the frequency, an illumination device using the same, and a refrigerated showcase.

  The conventional dimming discharge lamp lighting device shown in FIG. 15A includes a DC power supply circuit 1 that converts commercial power into DC voltage, and a switching element that converts DC voltage output from the DC power supply circuit 1 into high-frequency power. Inverter circuit 2 composed of Q1, Q2, etc., driving circuit 3 for driving switching elements Q1, Q2, and dimming signal S from outside, for driving switching elements Q1, Q2 at a predetermined frequency The frequency control circuit 4 outputs a drive frequency signal to the drive circuit 3, and both ends of both filaments of a discharge lamp La such as a fluorescent lamp are connected to both ends of the switching element Q2 via a resonance inductor L1. In addition, a resonance capacitor C1 is connected between the non-power supply side ends of the filaments on both sides.

  In this conventional apparatus, the driving frequency of the switching elements Q1 and Q2 of the inverter circuit 2 is changed in the range of the frequency f1 to the frequency f2 as shown in FIG. 15B to change the impedance of the load circuit including the discharge lamp La. As a result, the lamp current is changed. As a result, predetermined light control for changing the light output of the discharge lamp La between A of frequency f1 and B of frequency f2 is performed.

  However, in this conventional apparatus, when deeper dimming with the driving frequency of the frequency f2 or higher is performed, the discharge lamp La enters the unstable discharge region, so that there is a possibility that the light may disappear in some cases.

  For example, a discharge lamp lighting device disclosed in Patent Document 1 has been proposed as a countermeasure against the occurrence of the extinction.

  In the discharge lamp lighting device disclosed in Patent Document 1, the drive frequency can be varied between the frequency f1 and the frequency f0 as shown in FIG. 16A, and the light control at the drive frequency f0 is performed. When performing further deep light control, a drive frequency f0 that generates a high-frequency voltage sufficiently high for lighting a discharge lamp and a variable frequency fs within a predetermined period T as shown in FIG. It is characterized in that the inverter circuit is driven by switching, and lighting at a lower light output is possible by changing the frequency fs.

  A discharge lamp lighting device using another method (for example, Patent Document 2) has also been proposed.

In the discharge lamp lighting device disclosed in Patent Document 2, the driving frequency can be varied between the frequency f1 and the frequency f0 as shown in FIG. As shown in FIG. 17B, a frequency f0 for generating a high-frequency voltage sufficiently high for lighting the discharge lamp and a frequency fd higher than the frequency f0 are shown as a method of smoothly lighting and dimming without giving By alternately switching at a predetermined period T, and changing the ratio of the frequency f0 by relatively increasing from zero within the predetermined period T, the period during which the frequency f0 and the frequency fd are output is controlled, A method is employed in which the frequency f0 is changed after the period during which the frequency f0 is output reaches the entire region.
JP 61-221579 A JP 2005-203274 A

  However, in any of the above-mentioned conventional devices, when dimming the discharge lamp continuously, it is necessary to continuously use a wide frequency band. For example, other electronic devices (for example, an infrared remote controller or a specific frequency) When security tags that operate in close proximity to each other are used close to each other, there is a risk that interference will occur depending on the frequency, causing other electronic devices to malfunction.

  For this reason, it is necessary to take countermeasures against radio noise at a wide frequency band, and as a result, there is a problem that the design of a noise prevention filter and the like is complicated and costly.

  In addition, for example, when used in a refrigerated showcase, the wiring becomes very long, so the influence of parasitic capacitance generated between the wirings must be taken into consideration. Further, in general, in a refrigerated showcase, a resonance capacitor for an inverter circuit is often provided in advance, and this resonance capacitor has a relatively large capacitance of about 1 μF in order to reduce the influence of parasitic capacitance. The capacitor is used.

  For this reason, when the discharge lamp is lit at a high frequency, loss generated at the filament portion of the discharge lamp becomes large, which is very inefficient.

  Moreover, since it becomes high thermally, there is a risk of melting or the like for the resin socket. For this reason, in a discharge lamp lighting device used by being incorporated in a refrigerated showcase, it is necessary to make the oscillation frequency at the time of lighting as low as possible.

  The present invention has been made in view of the above-described points, and the object of the present invention is to operate other discharge devices by avoiding a specific frequency when the discharge lamp is continuously dimmed. It is to provide a discharge lamp lighting device capable of smoothly adjusting light while suppressing an influence on the lighting device, an illumination device using the same, and a refrigerated showcase.

In order to achieve the above object, according to the invention of the discharge lamp lighting device of claim 1, a power supply circuit for converting commercial power into DC power, and an inverter for converting the DC power into high frequency power and lighting the discharge lamp at high frequency A circuit, a drive circuit for driving a switching element of the inverter circuit, and a plurality of different drive frequencies among three or more drive frequencies are switched within a predetermined period and output to the drive circuit, and each of the drive frequencies A frequency control circuit that relatively changes an output period within a predetermined period, and when the plurality of different drive frequencies are switched within a predetermined period, the frequency control circuit has a pair of drive frequencies before and after switching. Of these, the higher drive frequency is set within 1.5 times the lower drive frequency .

According to the invention of the discharge lamp lighting device of the first aspect, when the discharge lamp is continuously dimmed, by operating while avoiding a specific frequency, while suppressing the influence on other electronic devices, and Dimming can be performed smoothly. Furthermore, the stress applied to the circuit elements of the inverter circuit can be reduced, so that it is possible to avoid an increase in the cost of the circuit elements.

In the invention of the discharge lamp lighting device of claim 2 , in the invention of claim 1 , a multi-lamp discharge lamp lighting device for supplying power to a plurality of discharge lamps is configured.

According to the invention of the discharge lamp lighting device of the second aspect , it is possible to provide the multi-lamp discharge lamp lighting device having the effects of the invention of the first aspect .

The invention of the discharge lamp lighting device according to claim 3 is characterized in that, in the invention of claim 2 , when a plurality of different drive frequencies are switched at a predetermined cycle, the phase of the predetermined cycle is controlled.

According to the invention of the discharge lamp lighting device of the third aspect , it is possible to reduce problems such as mutual interference and flickering of the light output of each discharge lamp, or by averaging the distortion of the DC power supply supplied from the DC power supply circuit. This can reduce circuit loss and prevent circuit elements from generating heat.

The invention of a discharge lamp lighting device according to claim 4 is characterized in that, in the invention of claim 2 or 3 , the phase of the drive frequency is controlled.

According to the invention of the discharge lamp lighting device of claim 4 , by controlling the phase of the driving frequency, it is possible to realize the discharge lamp lighting device having the effects of the invention of claim 2 .

The invention of the lighting device according to claim 5 is characterized in that the discharge lamp lighting device according to any one of claims 1 to 4 is used.

According to the invention of the illuminating device of the fifth aspect, the effect obtained by the discharge lamp lighting device according to any one of the first to fourth aspects allows smooth dimming while suppressing the influence on other electronic devices. An illumination device that can be provided can be provided.

The invention of the refrigerated showcase according to claim 6 is characterized in that the discharge lamp lighting device according to any one of claims 1 to 4 is used.

According to the invention of the refrigerated showcase of claim 6, the light effect can be smoothly adjusted while suppressing the influence on other electronic devices by the operational effect of the discharge lamp lighting device of any of claims 1 to 4. Can be provided.

  The present invention relates to a discharge lamp capable of smoothly adjusting light while suppressing influence on other electronic devices by operating while avoiding a specific frequency when the discharge lamp is continuously dimmed. There is an effect that a lighting device, a lighting device using the lighting device, and a refrigerated showcase can be provided.

Embodiments of the present invention will be described below.
(Embodiment 1)
This embodiment constitutes a separately-excited control type discharge lamp lighting device. As shown in FIG. 1, basically, as in the case of the discharge lamp lighting device shown in FIG. 1 and switching elements Q1. The inverter circuit 2 including Q2 and the like, the drive circuit 3, and the frequency control circuit 4 are configured. The frequency control circuit 4 generates a plurality of different fixed drive frequencies in order to control the optical output. These different drive frequencies are switched within a predetermined period and output to the drive circuit 3 as a signal for determining the frequency of the drive signal, and the period for outputting each drive frequency is relative within the predetermined period T. The characteristic is that the light output of the discharge lamp La made of a fluorescent lamp is controlled by changing the drive frequency and performing the same operation after the period of output of a certain drive frequency reaches the entire region. Have. In the figure, the same components as those in FIG. 15A are denoted by the same reference numerals. Further, in the figure, a DC cut capacitor and the like are omitted.

  FIG. 2A shows the relationship of the optical output with respect to the drive frequencies f1 to f3 output from the frequency control circuit 4, in which f1 is an optical output of 100%, f2 is an optical output of 50%, and f3 is an optical output of 5%. This is the output drive frequency. 2B and 2C show output control methods of the drive frequency of the frequency control circuit 4 for each optical output.

  Thus, when the optical output is controlled so as to be 5% to 50% corresponding to the dimming signal S, the frequency control circuit 4 has two of f2 and f3 as shown in FIG. A signal composed of two drive frequencies is alternately switched at a predetermined cycle T and output to the drive circuit 3, and the ratio of the drive frequency f2 and the drive frequency f3 is relatively changed within the cycle T. The high frequency power supplied to the discharge lamp La is controlled by driving the switching elements Q1 and Q2 of the inverter circuit 3 with the drive signal output from the drive circuit 2 by the controlled drive frequency, thereby performing dimming. .

  Further, when controlling the light output to be 50% to 100%, as shown in FIG. 2 (c), the dimming is performed by performing the same operation using the driving frequencies of fl and f2. Do.

  In the above example, three drive frequencies f1, f2, and f3 are set. However, the same control is possible even if the number of drive frequencies is increased, and control is performed by switching within a predetermined period T. The same control can be performed when the driving frequency to be increased is more than two. That is, as the driving frequency is increased, finer control is possible.

Thus, in this embodiment, a wide range of light output can be controlled by using a plurality of drive frequencies as described above. In addition, by selecting the driving frequency as a frequency that does not affect other electronic devices, it is possible to smoothly adjust the light without affecting other electronic devices. By selecting a particularly low frequency, light control can be performed while avoiding the frequency band of the infrared remote controller.
(Embodiment 2)
In the present embodiment, when a plurality of drive frequencies are switched and controlled as described above, a change width of the plurality of drive frequencies is reduced, for example, a change width of different drive frequencies (for example, f1 and f2) is set to f2 / f1 <. It is characterized in that it is limited to about 1.5. Note that the same circuit as used in the first embodiment is used.

FIG. 3A shows the relationship of the load circuit impedance (1 / Z) with respect to each drive frequency f1, f2 (and f2 ′). Here, when the drive frequency of the inverter circuit 2 is f1. The load circuit impedance is a, the load circuit impedance is b when the drive frequency is f2, and the load circuit impedance is b 'when the drive frequency is f2 ′. The relationship between the drive frequencies at this time is f1 <f2 ′ <f2.

  Here, when the two drive frequencies f2 and f1 are instantaneously switched at a predetermined period T, a change in the load circuit impedance causes a slight time lag compared to the switching time, which takes extra time. For this reason, at the moment when the driving frequency is switched from f2 to f1, the load circuit impedance gradually changes from ba to aa. On the other hand, when switching instantaneously at a predetermined period T between the two drive frequencies f2 'and f1, the load circuit impedance gradually changes from b'-a to aa.

  That is, the larger the change rate of the different driving frequency, the wider the change width of the load circuit impedance. Therefore, the voltage generated at both ends of the discharge lamp La increases, and the stress applied to the circuit elements of the inverter circuit 2 also increases. Will be.

  FIGS. 4A and 4B show measured waveforms of the voltage generated in the discharge lamp La when the configuration of the present embodiment is used, and FIGS. 5A and 5B show measured drain currents of the switching element Q2. As shown in FIGS. 4 (a) and 5 (a), when the change width (f2 / f1) between the drive frequency fl and the drive frequency f2 is 1.5 or more, the waveform is shown. The voltage generated in the lamp La and the drain current of the switching element Q2 are large, so that stress is generated in the circuit element. However, if the change width is suppressed to about 1.5 times or less, FIG. 4B and FIG. As shown in b), the voltage generated in the discharge lamp La and the drain current of the switching element Q2 are reduced, and the stress of the circuit element is lowered to a level where there is no problem.

  From the above, for example, if the driving frequency of f1 is 20 kHz, it is better to set f2 to about 30 kHz and f3 to about 45 kHz, and the driving frequency of f1 is 20 kHz and the driving frequency of f2 is 45 kHz. In the case where it is desired to achieve this, the same effect can be obtained by providing another section where f2 ′ = 30 kHz between the switching between the driving frequency f1 and the driving frequency f2.

Thus, in this embodiment, the output control method of the driving frequency is adopted in the frequency control circuit 4, so that the stress applied to the circuit elements of the inverter circuit 2 can be reduced and the cost of the circuit elements is avoided. It became possible.
(Embodiment 3)
The present embodiment is characterized in that f0, which will be described later, is added as a drive frequency for generating a high-frequency voltage sufficiently high to light the discharge lamp La with respect to the different drive frequencies in the first embodiment. The circuit used is the same circuit as in the first embodiment.

  That is, in this embodiment, as shown in FIG. 6, the drive frequency f0 and f5 that are alternately switched and output from the frequency control circuit 4 are set to f4 and f5, and the drive frequency f0 that generates a high-frequency voltage high enough to light the discharge lamp La. And When the relationship between the drive frequencies is f0 <f4 <f5, the drive frequency f0 is provided when the drive frequencies of f4 and f5 are alternately switched, and a drive signal based on these drive frequencies is output from the drive circuit 3 so that the inverter circuit 2 The switching elements Q1 and Q2 are driven.

Thus, in this embodiment, by adopting the drive frequency output control method as described above, it is possible to prevent the occurrence of extinction at the time of deep dimming.
(Embodiment 4)
The present embodiment is a multi-lamp discharge lamp lighting device adopting the drive frequency output control method of the first embodiment, and is provided with two sets of inverter circuits 2A and 2B as shown in FIG. High frequency power is supplied to the discharge lamps La1 and La2 connected correspondingly by 2A and 2B, respectively. The switching elements Q1a and Q2a of the inverter circuit 2A and the switching elements Q1b and Q2b of the inverter circuit 2B are alternately driven by the same drive signal from the drive circuit 3. In the figure, L11 and L12 denote resonance inductors, C11 and C12 denote resonance capacitors, and other components are denoted by reference numerals corresponding to the components in FIG.

  Thus, in the present embodiment, in order to drive the switching elements Q1a, Q2a, Q1b, Q2b of the inverter circuits 2A, 2B with the same drive signal from the drive circuit 3 corresponding to the drive frequency output from the frequency control circuit 4, There is no error in the oscillation frequency of both the inverter circuits 2A and 2B, so that the error of the light output between the discharge lamps La1 and La2 can be reduced, and the frequency control circuit 4 is shared, so that the circuit portion can be downsized. Is also effective.

The output control method of the drive frequency of the frequency control circuit 4 may be the method of the second to third embodiments. Further, the invention is not limited to two lamps, and a multi-lamp discharge lamp lighting device having three or more lamps can be configured by increasing the number of inverter circuits.
(Embodiment 5)
In the fourth embodiment, the switching elements Q1a and Q2a of the inverter circuit 2A and the switching elements Q1b and Q2b of the inverter circuit 2B are driven by the same drive signal from the drive circuit 3, but in this embodiment, different drive frequencies are set in advance. In order to be able to control the phase of a predetermined cycle for each discharge lamp when switching alternately in the cycle of, the drive signal given from the drive circuit 3 is divided for each of the inverter circuits 2A and 2B as shown in FIG. This is different from the fourth embodiment. In FIG. 8, the same circuit elements as those in FIG.

  Thus, when the phase of the cycle for switching the different drive frequencies corresponding to the inverter circuits 2A and 2B at a predetermined cycle is controlled to be in phase as shown in FIGS. 9A and 9B, Since the inverter circuit 2A and the inverter circuit 2B are driven by the drive signal having the drive frequency of the same phase, the discharge lamps La1. As in the fourth embodiment, it is possible to reduce problems such as mutual interference and flickering of the light output of La2.

On the other hand, when different drive frequencies are switched at a predetermined cycle, the phase of the cycle corresponding to both inverter circuits 2A and 2B is intentionally shifted as shown in FIGS. 10 (a) and 10 (b). The distortion of the DC power supplied from the DC power supply circuit 1 is averaged, and as a result, the power ripple can be reduced. This is effective in reducing circuit loss and preventing circuit elements from generating heat.
(Embodiment 6)
In the fifth embodiment, the phase of a cycle for switching different driving frequencies at a predetermined cycle can be intentionally shifted. In this embodiment, a circuit similar to that in the fourth or fifth embodiment is provided. Although used, it differs from the fifth embodiment in that the phase of the drive frequency corresponding to each inverter circuit 2A, 2B can be controlled.

  Thus, by setting the phase of the driving frequency of the switching elements Q1 and Q2 of each inverter circuit 2A and 2B to the same phase as shown in FIGS. 11 (a) and 11 (b), each discharge lamp La1. Problems such as mutual interference and flickering of the light output of La2 can be reduced.

On the other hand, the control of intentionally shifting the phase of the driving frequency of the switching elements Q1 and Q2 of the inverter circuits 2A and 2B as shown in FIGS. It is possible to reduce the power source ripple by averaging. The distortion of the DC power supplied from the DC power supply circuit 1 is averaged, and as a result, the power ripple can be reduced. This is effective in reducing circuit loss and preventing heat generation of components.
(Embodiment 7)
This embodiment corresponds to the invention of a lighting device (lighting fixture), and as shown in FIG. 13, the lighting device 100 of this embodiment mainly includes a lighting fixture body 10, a fixture reflector 11, and a fluorescent lamp. Two discharge lamps La1. It is comprised by La2 and the ballast 12.

  Here, the lighting fixture body 10 is provided with two pairs of lamp sockets 13 at both ends. Further, a reflector mounting bracket 14 is fixed to the luminaire main body 10 as a fixing means for attaching the fixture reflector 11 to the luminaire main body 10, and a knob screw 15 which is a decorative screw is opened on the fixture reflector 11. The lighting fixture main body 10 and the fixture reflecting plate 11 are fixed by screwing into the reflector mounting bracket 14 through the screw holes 11a. The lamp socket 13 is exposed to the front side of the fixture reflector 11 through a hole 23 opened in the fixture reflector 11.

  Furthermore, a ballast 12 for lighting the discharge lamps La1 and La2 at a high frequency of several tens to several hundreds kHz and a power line 16 such as VVF passing through the ceiling are directly connected to the lighting fixture body 10 through the power hole 17. A power terminal block 18 which is a connection means for connecting to the luminaire main body 10 is attached, and the ballast 12 is electrically connected to the power terminal block 10 and the lamp socket 5 by a power line (not shown).

  The lighting fixture main body 10 has a bolt mounting hole 19 in advance. The suspension bolt 20 suspended from the ceiling is passed through the bolt mounting hole 19 and is attached to the lower portion of the lighting fixture main body 10 by a washer 21 and a nut 22. It is attached to the ceiling by tightening.

  Here, the ballast 12 uses the discharge lamp lighting device for multiple lamps of any of the above-described Embodiments 4 to 6, or the discharge lamp lighting device for one lamp of Embodiments 1 to 3 for each discharge lamp. Two sets corresponding to La1 and La2 are used, and the lighting device 100 is configured by being attached to the lighting fixture body 10. The tubes of the discharge lamps La1 and La2 attached to each pair of lamp sockets 13 are held by support springs 24 attached to the instrument reflector 11.

In this embodiment, the lighting device 100 for two lamps is configured. However, the lighting device for one lamp is configured using the discharge lamp lighting device for one lamp as in the first to third embodiments. You can also.
(Embodiment 8)
This embodiment corresponds to the invention of the refrigerated showcase 200, and as shown in FIGS. 14 (a) and 14 (b), has an opening 25 for putting in / out a product on the front surface and is formed of a heat insulating wall. The showcase body 26 and the interior are partitioned into a product storage 28 and a cold air circulation duct 29 by a duct plate 27, a cooler 30 is disposed in the cold air circulation duct 29, and air is sucked into the lower end of the cold air circulation duct 29. A cold air outlet 32 is formed at the upper end of the mouth 31, a cold air curtain is formed in the opening 25 by the cold air blown out from the air outlet 32, and the inside of the product storage 28 is cooled and the outside air enters the interior Is preventing.

  Also, the temperature of the showcase body 26 and the temperature in the product storage 4 and the operation unit 33 of the control device for controlling the temperature of the showcase and controlling the lighting in the cabinet are displayed on the upper portion of the opening 25 of the showcase body 26. A temperature indicator 34 is provided.

  Furthermore, in order to brighten the inside of the “product storage”, a discharge lamp La made of a fluorescent lamp is attached to each storage shelf 35, and the discharge lamp lighting device of the present invention is used to stabilize the discharge lamp La. The vessel 36 is attached to the upper and lower portions of the showcase body 26, and these constitute a refrigerated showcase 200.

As the ballast 36, a discharge lamp lighting device for one lamp (Embodiments 1 to 3) is used corresponding to the number of discharge lamps, or a discharge lamp lighting device for multiple lamps corresponding to the number of discharge lamps. (Corresponding to Embodiments 4 to 6).

It is a circuit block diagram of the discharge lamp lighting device of Embodiment 1. (A) is a relationship diagram between the optical output and the drive frequency in the above, and (b) and (c) are explanatory diagrams of the output control of the drive frequency of the frequency control circuit in the above. It is a relation explanatory drawing of load circuit impedance and drive frequency in a discharge lamp lighting device of Embodiment 2. (A), (b) is the measurement waveform figure of the both-ends voltage of the discharge lamp in the same as the above. (A), (b) is the measured waveform figure of the drain-source current of the switching element Q2 of the inverter circuit in the same as the above. It is explanatory drawing of the output control of the drive frequency of the frequency control circuit in Embodiment 3. It is a circuit block diagram of the discharge lamp lighting device of Embodiment 4. It is a circuit block diagram of the discharge lamp lighting device of Embodiment 5. (A), (b) is an output waveform diagram of the frequency control circuit when the phase of the switching period of different drive frequencies corresponding to each inverter circuit in the above is the same. (A), (b) is an output waveform diagram of the frequency control circuit when the phase of the switching period of the different drive frequency corresponding to each inverter circuit is shifted. (A), (b) is a wave form diagram of a drive frequency at the time of making the phase of the drive frequency corresponding to each inverter circuit in Embodiment 6 into the same phase. (A), (b) is a waveform diagram of the drive frequency when the phase of the drive frequency corresponding to each inverter circuit in the above is shifted. It is a disassembled perspective view of the illuminating device (lighting fixture) of Embodiment 7. FIG. (A) Front view of refrigerated showcase of Embodiment 8, (b) is a side sectional view (A) is a circuit block diagram of a conventional circuit, and (b) is a relationship diagram between the optical output and the drive frequency in the same as above. (A) is a related figure of the optical output and drive frequency in another conventional circuit. (B) is an output waveform diagram of the frequency control circuit in the same as above. (A) is a related figure of the optical output and drive frequency in another conventional circuit. (B) is an output waveform diagram of the frequency control circuit in the same as above.

DESCRIPTION OF SYMBOLS 1 DC power supply circuit 2 Inverter circuit 3 Drive circuit 4 Frequency control circuit Q1, Q2 Switching element L1 Resonance inductor C1 Resonance capacitor S Dimming signal La Discharge lamp

Claims (6)

A power supply circuit for converting a commercial power supply into a DC power supply, an inverter circuit for converting the DC power supply into high-frequency power to light a discharge lamp at a high frequency, a drive circuit for driving a switching element of the inverter circuit, and three or more drives A frequency control circuit that switches a plurality of different drive frequencies out of frequencies within a predetermined period and outputs the same to the drive circuit, and relatively changes a period for outputting each drive frequency within the predetermined period ,
When switching the different drive frequencies within a predetermined period, the frequency control circuit sets the higher drive frequency within 1.5 times the lower drive frequency among the pair of drive frequencies before and after switching. A discharge lamp lighting device characterized by:   The discharge lamp lighting device according to claim 1, wherein the discharge lamp lighting device is configured to supply electric power to a plurality of discharge lamps.   The discharge lamp lighting device according to claim 2, wherein when a plurality of different driving frequencies are switched at a predetermined cycle, the phase of the predetermined cycle is controlled.   The discharge lamp lighting device according to claim 2 or 3, wherein the phase of the driving frequency is controlled.   An illumination device comprising the discharge lamp lighting device according to any one of claims 1 to 4.   A refrigerated showcase comprising the discharge lamp lighting device according to any one of claims 1 to 4.

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