JP6509921B2 - Discharge lamp lighting device - Google Patents

Description

  The present invention relates to a discharge lamp lighting device for lighting a discharge lamp.

  As a lighting device of a discharge lamp, there is, for example, one as disclosed in Patent Document 1. In the technique of Patent Document 1, the abnormal arc of the discharge lamp is detected based on the current flowing to the lamp and the voltage applied to the lamp.

JP, 2004-311199, A

  In patent document 1, although abnormality in arcs, such as an arc jump and an arc flicker, is detected, for example using the technique which detects the electric current which flows into a discharge lamp, the electric current which flows into a discharge lamp is higher than a predetermined reference current When it becomes smaller, it is conceivable that the power supply by the discharge lamp is stopped and the light is turned off, because an abnormality is detected. However, in this technology, when the lamp state at the beginning of lighting of the discharge lamp is unstable, the current flowing through the lamp is smaller than the reference current, and it is erroneously detected as abnormal even though the discharge lamp is not lit yet. Sometimes, the power supply to the discharge lamp may be interrupted inadvertently, which causes the discharge lamp to fail frequently.

  An object of the present invention is to provide a discharge lamp lighting device which prevents the discharge lamp from lighting failure frequently.

The discharge lamp lighting device of one aspect of the present invention has a power supply means. The power supply means supplies an operating voltage to the discharge lamp in response to the start signal. The power supply means has a closing means, superimposed temporarily the operating voltage period crowned voltage the switching means is closed in the supply state of the operating voltage, the switching means in the supply state of the operating voltage Stop the superposition of the high voltage when it is open. The abnormality detection unit operating from the time of supply of the operating voltage outputs an abnormality detection signal when the output current supplied from the power supply unit to the discharge lamp is smaller than a predetermined value. An invalidation means generates an invalidation signal for a predetermined time from the supply of the activation signal. In the supply state of the operating voltage , the control means stops the supply of the operating voltage and closes the switching means in response to the generation of the abnormality detection signal after the end of the generation of the invalidation signal, and the supply state of the operating voltage The switching means is closed in response to the occurrence of the abnormality detection signal during the generation of the invalidation signal, and the switching means is in response to the disappearance of the abnormality detection signal during the generation of the invalidation signal in the supply state of the operating voltage. open.

In the discharge lamp lighting device configured as described above, the invalidation means is activated even if the abnormality detection means operating from the time of supply of the activation signal generates an abnormality detection signal during a predetermined time from the time of supply of the activation signal. Since the disabling voltage of the discharge lamp is generated, the operating voltage of the discharge lamp is not stopped, and the switching means is closed when supplying the start signal, so the high voltage is superimposed on the operating voltage and the discharge lamp When it lights up, the switching means is opened and the superposition of the high voltage is stopped. Therefore, when the discharge lamp is in an unstable state at the initial stage of lighting , the supply of the operating voltage to the discharge lamp is not erroneously stopped. In addition, when the discharge lamp has already been abnormal, the abnormality detection signal is activated when a predetermined time elapses, so the abnormality of the discharge lamp is immediately detected, and the switching means continues to be closed. the supply of operating voltage to the left discharge lamp is stopped. In addition, when an abnormality occurs in the discharge lamp after a lapse of a predetermined time, the abnormality detection means immediately detects an abnormality, and the operating voltage to the discharge lamp is stopped, and the switching means is changed according to the supply stop of the operating voltage. Close and prepare for the next lighting of the discharge lamp.

The abnormality detecting means outputs the abnormality detection signal during said predetermined time, after it is lost, when again the abnormality detecting means outputs the abnormality detection signal, the switching means is closed, the high The voltage can be superimposed again.

  According to this configuration, even if lighting of the discharge lamp fails once during a predetermined time, the high voltage is superimposed again, so that the possibility of lighting the discharge lamp can be increased.

  It is also possible to provide counting means for counting the number of high voltage re-overlaps. In this case, the power supply means is stopped when the counting of the counting means reaches a predetermined number or more.

  With this configuration, if the discharge lamp can not be turned on even if the high voltage superposition is repeated a predetermined number of times or more, for example, it can be determined that the discharge lamp has a failure. Supply can be stopped.

  In the aspect described above, the invalidation means can be a timer that responds to the activation signal and counts the predetermined time.

  Furthermore, changing means for changing the predetermined time with respect to the timer may be provided.

  For example, when approaching the life of the discharge lamp and it takes a long time to light the discharge lamp, if the invalidation is stopped in the predetermined time, it is detected that the discharge lamp is abnormal and the discharge is discharged. Power supply to the lamp is stopped. However, the possibility of lighting the discharge lamp can be increased by changing the predetermined time for the timer to a long time by the changing means.

  As described above, according to the present invention, the lighting performance of the discharge lamp can be improved by providing the invalidation means even when using the abnormality detection means operating at the time of supplying the start signal. .

It is a block diagram of a discharge lamp lighting device of one embodiment of the present invention. It is a block diagram of the control circuit of the discharge lamp lighting device of FIG. It is a wave form diagram of each part of the lighting device of FIG. 1 when a discharge lamp lights normally. It is a wave form diagram of each part of a lighting device of Drawing 1 when a discharge lamp has failed lighting once, and lighting is performed again. It is a wave form diagram of each part of a lighting device of Drawing 1 when a discharge lamp lights up normally and abnormalities are detected after progress of fault detection waiting time. It is a wave form diagram of each part of a lighting device of FIG. 1 at the time of detecting abnormalities immediately after abnormality detection waiting time progress, without a discharge lamp lighting up within abnormalities detection waiting time. It is a flowchart which shows the process which CPU52 of FIG. 2 performs. It is a figure which shows a part of one modification of the process which CPU52 of FIG. 2 performs. It is a figure which shows a part of one modification of the process which CPU52 of FIG. 2 performs.

  A discharge lamp lighting device according to an embodiment of the present invention is for lighting, for example, a discharge lamp 2 provided in a projector, and includes power supply means, for example, a power supply circuit 4 as shown in FIG. The power supply circuit 4 rectifies an AC voltage from the commercial AC power supply 6 in the rectifier circuit 8, improves the power factor of its rectified output by the power factor correction (PFC) circuit 10, and converts it into a high frequency voltage by the inverter 12. Supply to the primary winding 14p of the transformer 14.

  The transformer 14 has two secondary windings 14s1 and 14s2. One end of the secondary winding 14s1 is connected to a reference potential point, for example, the ground potential, and the other end is connected to the anode of the diode 16. The rectified voltage generated between the cathode of the diode 16 and the secondary winding 14s1 is supplied to one end of the discharge lamp 2 via the igniter circuit 18. The other end of the discharge lamp 2 is connected to the ground potential.

  Among the both ends of the secondary winding 14s2, one end is connected to the secondary winding 14s1, and the other end is a capacitor through a series circuit of a diode 20 and high voltage superposition switching means, eg relay (RY) contact 22 Connected to one end of 24. The other end of the capacitor 24 is connected to one end of the secondary winding 14s1 via a reactor 26. When the relay contact 22 is closed, the high frequency voltage generated between the series connected secondary windings 14s1 and 14s2 is rectified by the diode 20. This rectified voltage is larger than the rectified voltage generated between the cathode of the diode 16 and one end of the secondary winding 14s1. These two rectified voltages are a resistor 28 connected between the cathode of the diode 16 and one end of the secondary winding 14s1, and a resistor 30 connected between the cathode of the diode 16 and one end of the capacitor 24. , And the superimposed voltage is supplied to the discharge lamp 2 via the igniter circuit 18. When the relay contact 22 is opened, the anode of the diode 32 is connected to the connection point between the reactor 26 and the secondary coil 14s1 in order to circulate current based on the back electromotive force generated in the reactor 26, and the cathode of the diode 32 Are connected to the junction of the diode 16 and the resistor 28. Thus, a DC-DC converter is configured by the inverter 12, the transformer 14, the diodes 16, 20, 32, the relay contact 22, the capacitor 24, the reactor 26, the resistors 28, 30 and the igniter circuit 18.

  The inverter 12 has a plurality of semiconductor switching elements, such as IGBTs or MOSFETs, and generates a high frequency voltage by on / off controlling these. The voltage across the resistor 28, which is the output voltage of the power supply circuit 4, is detected by the voltage detector 33 for controlling the semiconductor switching element and the relay contact 22, and the output current from the power supply circuit 4 Is detected by the current transformer 34 connected in series to the reactor 26.

  The output voltage detection signal output from the voltage detector 33 is supplied to the control means, for example, the input terminal 38 of the control device 36 as shown in FIG. 2, and the output current detection signal output from the current transformer 34 is the control device 36. Is supplied to the input terminal 40 of the Further, to the input terminal 42 of the control device 36, a lamp on signal for instructing lighting (on) of the discharge lamp 2 is also supplied. The lamp on signal is generated, for example, by a user operating a switch of a projector in which the discharge lamp is used. The output voltage detection signal, the output current detection signal, and the lamp on signal are supplied to the inverter control unit 44. The inverter controller 44 controls the inverter 12 to turn on and off each semiconductor switching element of the inverter 12 based on the output current detection signal and the output voltage detection signal while the lamp on signal is being supplied. Supplied.

  The output current detection signal supplied to the input terminal 40 is supplied to the abnormality detection means, for example, the undercurrent detection circuit 46, and the output current detection signal is higher than the undercurrent reference value signal corresponding to the predetermined undercurrent reference value. When it is small, it outputs an undercurrent detection signal. Also, is the output voltage detection signal supplied to the input terminal 38 supplied to the abnormality detection means, for example, the voltage abnormality detection circuit 48, and is the output voltage detection signal larger than the overvoltage reference signal corresponding to the predetermined overvoltage? When the voltage is smaller than an under voltage reference signal corresponding to a predetermined under voltage, an abnormality detection signal is output.

  The lamp-on signal supplied to the input terminal 42 is also supplied to the disabling means, for example, the false detection latency timer 50. The false detection waiting time timer 50 starts counting the clock signal (not shown) in response to the rising of the lamp on signal, and continues to invalidate signals until it counts clock signals by a number corresponding to a predetermined false detection waiting time. Occur.

  The undercurrent detection signal, the abnormality detection signal, and the invalidation signal are supplied to the CPU 52, for example. The CPU 52 controls the relay contact 22 and the inverter control unit 44 as shown in FIG. 3 to FIG. 6 based on these signals. In any case, it is assumed that relay contact 22 is initially closed, inverter 12 is stopped, and an undercurrent detection signal is also generated.

  FIG. 3 shows the case where the discharge lamp 2 is normally turned on in response to the supply of the lamp on signal, and when the lamp on signal is supplied as shown in FIG. 3 (c), the inverter signal as shown in FIG. 3 (f). Is supplied from the inverter control unit 44 to the inverter 12, the inverter 12 generates a high frequency voltage, and the relay contact 22 is closed, so that the discharge lamp 2 is initially set as shown in FIG. An output voltage to which a high voltage is applied is supplied for ignition of the discharge lamp 2. Along with this, the output current starts to rise as shown in FIG. While this output current is less than the undercurrent reference signal, the undercurrent detection circuit 46 supplies the undercurrent detection signal to the CPU 52 as shown in FIG. The false detection waiting time timer 50 supplies an invalidation signal to the CPU 52. As a result, the CPU 52 does not supply the stop signal to the inverter control unit 44, and the inverter 12 continues its operation. Eventually, when the output current exceeds the undercurrent reference value as shown in (b) of the figure, the discharge lamp 2 starts lighting, and the undercurrent detection signal disappears as shown in (d) of the figure. At the same time, the CPU 52 opens the relay contact 22 and the superposition of the high voltage is stopped as shown in FIG.

  It is assumed that the lighting state of the discharge lamp 2 is normally maintained after the lapse of the abnormality detection waiting time. Eventually, as shown in FIG. 6C, the lamp on signal is turned off, and the CPU 52 causes the inverter control unit 44 to stop the inverter signal. As a result, the output voltage decreases as shown in (a) in the figure, and the output current becomes smaller than the under-reference current as shown in (b) in the figure, and as shown in (d) in the figure A detection signal is generated, and the CPU 52 closes the relay contact 22 as shown in FIG.

  As described above, even within the abnormality detection waiting time, an undercurrent flows until the discharge lamp 2 lights up, but the abnormality detection is not performed and the inverter 12 is not stopped.

  FIG. 4 shows that the discharge lamp 2 is ignited in response to the supply of the lamp-on signal, but when the ignition is retried within the abnormality detection waiting time without lighting normally, the output current is under-referenced. It is the same as the case of FIG. 3 up to the point that the relay contact 22 is opened beyond the current. However, since the lamp is not lighted normally, the output current drops below the under-reference value as shown in (b) of the figure, and the under-current detection circuit 46 shows the under-current detection signal as shown in (d). As a result, the relay contact 22 is closed again as shown in FIG. 6E, the high voltage is superimposed again on the output voltage as shown in FIG. 6A, and the ignition is retried. As a result, the output current becomes larger than the under-reference current as shown in FIG. 7 (b), the under-current detection signal disappears as shown in FIG. 7 (d), and the relay contact 22 is opened.

  As described above, even within the abnormality detection waiting time, when lighting of the discharge lamp fails, the inverter 12 is not stopped even if an undercurrent detection signal is generated, and reignition is performed on the discharge lamp 2. It will be. If the discharge lamp 2 does not turn on even once, it will be fired again.

  FIG. 5 shows the case where the discharge lamp 2 is normally turned on but the output current becomes smaller than the under-reference current after the elapse of the abnormal waiting time. Until the elapse of the abnormal waiting time, it is the same as the case where the discharge lamp 2 is lit normally in FIG. When the output current becomes equal to or less than the under-reference current as shown in (b) of the figure due to some abnormality after elapse of the abnormal waiting time, an under-current detection signal is generated as shown in (d) of the figure. , Stops the inverter signal as shown in FIG. Along with this, the supply of the output voltage to the discharge lamp 2 is stopped as shown in FIG. In addition, the CPU 52 closes the relay contact 22 to prepare for lighting of the discharge lamp 2 next time. Although not shown, the voltage abnormality detection circuit 48 sends an abnormality detection signal to the CPU 52 when the output voltage becomes larger than the excessive reference voltage or smaller than the excessive reference voltage in addition to the abnormality of the output current. Supply and, as described above, the CPU 52 shuts off the inverter signal and closes the relay contact 22.

  As described above, when an abnormality occurs after the elapse of the abnormality detection waiting time, the inverter 12 is stopped and the relay contact 22 is closed.

  FIG. 6 shows the case where the lighting of the discharge lamp 2 fails, and the lamp on signal is supplied as shown in FIG. 6C, and the inverter signal is supplied to the inverter 12 as shown in FIG. The relay contact 22 is closed as shown in (e) of the figure, and the discharge lamp 2 can be operated as shown in (a) of FIG. Even when the output current is smaller than the under-reference current without turning on and the under-current detection signal is generated as shown in (d) of the figure, the CPU 52 supplies the inverter signal during the abnormality detection waiting time. continuing. However, when the abnormality detection waiting time has elapsed, the CPU 52 stops the inverter signal and stops the inverter 12 as shown in FIG. The relay contact 22 continues the closed state even after the inverter 12 is stopped.

  As described above, when the lighting fails, the inverter 12 is immediately stopped when the abnormality detection waiting time passes.

  In order to operate as described above, the CPU 52 executes processing as shown in FIG. First, the CPU 52 determines whether a lamp on signal is input (step S2). If the answer to this determination is no, the CPU 52 supplies an inverter stop signal to the inverter control unit 44 (step S4), whereby the inverter control unit 44 stops the inverter 12 without generating an inverter signal. Next, the CPU 52 determines whether the undercurrent is not detected (step S4). That is, it is determined whether the undercurrent detection signal is not supplied to the CPU 52 (step S6). If the answer to this determination is no, that is, if an undercurrent is detected, the CPU 52 supplies an on signal to the relay contact 22 to close the relay contact 22 (step S8), and executes step S2 again. If the answer to the determination in step S6 is yes, that is, no undercurrent is detected, the CPU 52 supplies an off signal to the relay contact 22 to open the relay contact 22 (step S10), and step S2 again. Run.

If the answer to the determination in step S2 is yes, that is, if the instruction to turn on the discharge lamp 2 is supplied to the CPU 52, the inverter control unit 44 is also supplied with the lamp on signal. An inverter signal is supplied from the control unit 44. If the answer to the determination in step S2 is yes, the CPU 52 determines whether the undercurrent is not detected (step S12). If the answer to this determination is no , that is, if an undercurrent is detected, it is determined whether the discharge lamp 2 has been lit (step S14). This determination is made based on, for example, whether the undercurrent detection signal has been detected in the past.

  If it is determined in step S12 that an undercurrent detection signal has not been generated in the past and the undercurrent detection signal has been generated in step S12, the discharge lamp 2 has not been lit yet, so the answer to the determination in step S14 Is no. If the undercurrent detection signal is generated in step S12 even though there is an undercurrent detection signal in the past, the discharge lamp 2 once turned on but has not been ignited completely, so the answer to this judgment is yes Become.

  If the answer to the determination in step S14 is no, the CPU 52 supplies an ON signal to the relay contact 22 as the first ignition (step S16). If the answer to the determination in step S14 is yes, the CPU 52 supplies an on signal to the relay contact 22 for retrying the firing (step S18).

  If the answer to the determination in step S12 is yes, that is, if it is determined that an output current larger than the under-reference current is flowing, the CPU 52 supplies an off signal to the relay contact 22 (step S20). This stops the superposition of the high voltage on the output voltage.

  Following step S16, S18 or S20, the CPU 52 determines whether the invalidation signal is supplied to the CPU 52 from the erroneous detection waiting time timer 50 (step S22). If the answer to this determination is yes, the abnormality detection waiting time has not yet elapsed, so the CPU 52 executes step S2 again. That is, after the lamp-on signal is input, if the under-output current is detected during the abnormality detection waiting time, the on-signal is supplied to the relay contact, but the inverter 12 is not stopped, as shown in FIG. The lamp lighting device operates as during the abnormality detection waiting time of FIG. 4, FIG. 4, FIG. 5 or FIG.

If the answer to the determination in step S22 is no, that is, if the abnormality detection waiting time has elapsed, the CPU 52 starts the abnormality detection. That is, the CPU 52 determines whether the undercurrent is not detected (step S24). If the answer to this determination is no , the CPU 52 supplies an inverter stop signal to the inverter control unit 44, stops the inverter 12, and supplies an on signal to the relay contact 22 (step S26). Thus, the lighting device operates as shown in the abnormal waiting time elapsed in FIG. 5 or FIG. At this time, it is also possible to output a signal from the CPU 52 to notify the projector of a lamp abnormality. After step S26, the CPU 52 executes an abnormal reset waiting process which is performed until the abnormal state is reset (step S28).

If the answer to the determination in step S24 is yes, the CPU 52 executes the voltage abnormality process (step S30). In this process, the CPU 52 determines whether or not the abnormality detection signal is supplied to the CPU 52 from the voltage abnormality detection circuit 48. If the abnormality detection signal is not supplied, step S2 is executed. When the abnormality detection signal is supplied to the CPU 52, the CPU 52 supplies an inverter stop signal to the inverter control unit 44 to stop the inverter 12 and close the relay contact 22, and is similar to the above-mentioned abnormality reset waiting process. Do the processing.

  In the above embodiment, although the abnormality detection waiting time is a fixed time, it may be changed according to the use situation of the discharge lamp 2. For example, in the case of a discharge lamp whose life is approaching, the output voltage at the time of starting, that is, at the time when the supply of the output voltage is disclosed becomes high. As shown in FIG. 8, the CPU 52 determines whether the output voltage at startup is equal to or higher than a predetermined value (step S32). If the answer is yes, the abnormality detection wait time is, for example, in advance compared to the time up to now. The set time is set longer (step S34). That is, the CPU 52 can also be used as a changing unit that changes the false detection waiting time of the false detection waiting time timer 50.

  In the above embodiment, after the firing retry is performed in step S18, the process of step S22 is performed. However, as shown in FIG. 9, after the process of step S18, the number of retries is counted (step S36). ), It is determined whether or not the number of retries is equal to or greater than a predetermined number (step S38). If the answer to the determination is no, step S22 is executed, and if the answer to the determination is yes, the inverter control unit 44 is The inverter stop signal is supplied to stop the inverter 12, and the on signal is supplied to the relay contact 22 (step S40). According to this configuration, when the discharge lamp 2 does not light even if it is retried a predetermined number of times or more, the lighting device can be stopped on the assumption that the discharge lamp 2 is abnormal.

  In the above embodiment, although the undercurrent detection circuit 46 and the voltage abnormality detection circuit 48 are provided as the abnormality detection means, only one of them may be provided. Further, although the voltage abnormality detection circuit 48 is configured to detect the output excessive voltage and the output under voltage, it is possible to detect only one of them. In the above embodiment, the undercurrent detection circuit 46, the voltage abnormality detection circuit 48, and the false detection waiting time timer 50 are provided separately from the CPU 52, but the undercurrent detection circuit 46, the voltage anomaly detection circuit and the false detection waiting time are provided. It is also possible to remove the timer 50 and implement these functions by the CPU 52.

4 Power supply circuit 36 Control device 50 False detection waiting time timer (invalidation means)

Claims (5)

The power supply means for supplying an operating voltage to the discharge lamp in response to the start signal, has the power supply means opening and closing means, a period domed voltage is Oite the switching means is closed when the supply of the operating voltage when the switching means is open in the supply state of the temporarily superimposed on the operating voltage, the operating voltage, said power supply means to stop the superposition of the high voltage,
Abnormality detection means which operates from the time of supply of the operating voltage and outputs an abnormality detection signal when the output current supplied from the power supply means to the discharge lamp is smaller than a predetermined value;
Invalidation means for generating an invalidation signal over a predetermined time from the time of supply of the activation signal;
Close the supply stops and the switching means of said operating voltage in response to the occurrence of the abnormality detection signal after generation completion of the invalidation signal in the supply state of the operating voltage, the invalidation signal in the supply state of the operating voltage Control means for closing the switching means in response to the generation of the abnormality detection signal during generation of the switching means, and for opening the switching means in response to the disappearance of the abnormality detection signal during generation of the invalidation signal in the supply state of the operating voltage. And
Discharge lamp lighting device.   The discharge lamp lighting device according to claim 1, wherein the abnormality detection means outputs the abnormality detection signal during the predetermined time, and after the disappearance, the abnormality detection means outputs the abnormality detection signal again. A discharge lamp lighting device, wherein when the switching means is closed, the high voltage is superimposed again.   The discharge lamp lighting device according to claim 1 or 2, further comprising: counting means for counting the number of times of re-superimposition of the high voltage, and the power supply means is used when the counting of the counting means reaches a predetermined number or more. Discharge lamp lighting device to stop.   The discharge lamp lighting device according to any one of claims 1 to 3, wherein the disabling means is a timer that responds to the start signal and counts the predetermined time.   5. The discharge lamp lighting device according to claim 4, further comprising changing means for changing the predetermined time.

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