JPH11162666A - High-pressure discharge-lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-pressure discharge-lamp lighting device detecting and eliminating abnormal discharge of a high-pressure discharge lamp. SOLUTION: This device is equipped with an inverter 5 for converting an output voltage of an active filter 3 into a low-frequency alternating voltage and supplying it to a high-pressure discharge lamp 6, a high-voltage pulse generating circuit 7 for generating high-pressure pulses in order to start the high- pressure discharge lamp 6, a voltage detecting circuit 12 for detecting a voltage supplied to the high-pressure discharge lamp 6, a current detecting circuit 11 for detecting a current flowing through the high-pressure discharge lamp 6, and a control circuit 13 which judges discharge of the high-pressure discharge lamp 6 to be abnormal, when a detected voltage is above a fixed voltage value and a detected current is below a fixed current value, and turns off the high- pressure discharge lamp 6 when the discharge is judged to be abnormal, and causes the high-pressure discharge lamp 6 to discharge again after a fixed amount of time Tg has passed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high pressure discharge lamp lighting device for preventing abnormal discharge of a high pressure discharge lamp.

[0002]

2. Description of the Related Art A high pressure discharge lamp lighting device for restarting a high pressure discharge lamp when it is turned off is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-307696. In this prior art, when the high pressure discharge lamp goes out despite the power being turned on, the operation of the high voltage generating circuit (igniter) is immediately restarted to restart the discharge lamp, If the high-pressure discharge lamp does not restart after the time required for restart has elapsed, it is determined that the high-pressure discharge lamp cannot be turned on, and the operation of the high-voltage generation circuit is performed after the elapse of the time set by the timer. It is designed to stop.

[0003]

The above-described conventional high pressure discharge lamp lighting device, when detecting the disappearance of the high pressure discharge lamp,
Although the high-voltage generation circuit is operated for a predetermined time, there is no means for eliminating the abnormal discharge state when an abnormal discharge occurs at the time of restart, so that the abnormal discharge state may continue. In such a case, not only the predetermined brightness cannot be obtained, but also the life of the high-pressure discharge lamp is significantly shortened. Usually, arc 2 of high pressure discharge lamp
3 occurs between the tips of the electrodes 21 as shown in FIG. 15, but when the high pressure discharge lamp is restarted, the energy level between the tips of the electrodes 21 is not necessarily the lowest due to the temperature distribution of the internal gas. Since there is no limitation, the arc 23 is placed between the tips of the electrodes 21.
Did not occur, and an abnormal discharge in which the arc 23 grew in the middle of the electrode 21 was sometimes generated (see FIG. 16). When this abnormal discharge occurs, the discharge distance is extended as can be seen from FIG. 16, so that the voltage applied to the high pressure discharge lamp is higher than the normal voltage in proportion to the distance. Further, when the applied voltage increases, the control means narrows down the target current that is optimal for the discharge accordingly, so that the current flowing through the high-pressure discharge lamp is smaller than usual.

In order to solve the above-mentioned problems, the present invention provides a high-pressure discharge lamp lighting device which detects abnormal discharge of a high-pressure discharge lamp from a voltage or a current at the time of abnormal discharge and eliminates the discharge. Aim.

[0005]

According to the present invention, there is provided a high pressure discharge lamp lighting apparatus comprising: a high pressure discharge lamp; and an inverter which converts a DC voltage into a low frequency AC voltage and supplies the AC voltage to the high pressure discharge lamp. A high voltage generation circuit for generating a high voltage for starting the high pressure discharge lamp, a voltage detection circuit for detecting a voltage supplied to the high pressure discharge lamp, and a current detection circuit for detecting a current flowing through the high pressure discharge lamp A discharge state determining means for determining that the discharge of the high pressure discharge lamp is abnormal when the detected voltage is equal to or higher than a predetermined voltage value and the detected current is equal to or lower than a predetermined current value; And a discharge control means for turning off the high-pressure discharge lamp when it is determined that the predetermined time Tg has elapsed and restarting the high-pressure discharge lamp.

A high-pressure discharge lamp, an inverter that converts a DC voltage to a low-frequency AC voltage and supplies the low-voltage AC voltage to the high-pressure discharge lamp, and a high-voltage generator that generates a high voltage for starting the high-pressure discharge lamp. A voltage generation circuit, a voltage detection circuit for detecting a voltage supplied to the high-pressure discharge lamp, and a discharge for determining that the discharge of the high-pressure discharge lamp is abnormal when the detected voltage is equal to or higher than a predetermined voltage value for a predetermined time T1. A state determination unit; and a discharge control unit that turns off the high-pressure discharge lamp when the discharge state determination unit determines that the discharge is abnormal, and restarts the high-pressure discharge lamp after a lapse of a predetermined time Tg.

[0007] Further, a high-pressure discharge lamp, an inverter that converts a DC-converted voltage into a low-frequency AC voltage and supplies the AC voltage to the high-pressure discharge lamp, and a high-voltage generator that generates a high voltage for starting the high-pressure discharge lamp. A voltage generation circuit, a current detection circuit for detecting a current flowing through the high-pressure discharge lamp, and a discharge state determination for determining that the discharge of the high-pressure discharge lamp is abnormal when the detected current is a predetermined current value continuously for a predetermined time T2. Means; and discharge control means for turning off the high-pressure discharge lamp when the discharge state determination means determines abnormal discharge, and restarting the high-pressure discharge lamp after a lapse of a predetermined time Tg.

[0008] The discharge control means, when the discharge state determination means determines that the discharge is abnormal, causes the current flowing through the high pressure discharge lamp to flow more than usual.

Further, the high pressure discharge lamp lighting device according to the present invention comprises a high pressure discharge lamp, an inverter for converting a voltage converted into direct current into a low frequency alternating voltage and supplying the low voltage alternating voltage to the high pressure discharge lamp, and the high pressure discharge lamp. A high-voltage generating circuit for generating a high voltage for starting the motor, a current detecting circuit for detecting a current flowing through the high-pressure discharge lamp, and determining whether the detected current is equal to or more than a predetermined value α. When the value is less than α, a discharge state determination unit that determines that the discharge of the high pressure discharge lamp is abnormal,
When it is determined that the discharge is abnormal by the discharge state determination means, the inverter and the high-voltage generation circuit are driven intermittently by inserting a preset pause time, and the detected current does not exceed a predetermined value α. When the intermittent driving is repeated a predetermined number of times, a control means is provided for setting the pause time longer to intermittently drive the inverter and the high voltage generating circuit.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. FIG. 1 is a block diagram of a high pressure discharge lamp lighting device according to a first embodiment of the present invention,
In the figure, 1 is a commercial power supply, 2 is a full-wave rectifier circuit for full-wave rectification of the AC voltage of the commercial power supply 1, 3 is an active filter that converts the output of the full-wave rectifier circuit 2 to DC with a high power factor, and 4 is a high voltage A current limiting circuit for controlling a current flowing through the discharge lamp 6, an inverter 5 which converts a DC voltage into a low-frequency AC voltage and supplies it to the high-pressure discharge lamp 6, and 7 outputs a high-voltage pulse when the high-pressure discharge lamp 6 starts. This is a high-voltage pulse generation circuit that discharges by discharging.

Reference numeral 8 denotes a control power supply circuit for generating a power supply for a control circuit 13 described later, 9 denotes an active filter output voltage detection circuit for detecting the output voltage of the active filter 3, and 10 denotes a differential amplifier circuit. The current limiting circuit 4 is controlled so that the current from the current detection circuit 11 for detecting the flowing current matches the target current IM output from the control circuit 13. Reference numeral 12 denotes a voltage detection circuit that detects a voltage supplied to the high-pressure discharge lamp 6.

A control circuit 13 includes means for controlling the active filter 3, the inverter 5, and the high-voltage pulse generating circuit 7, and a detection voltage of the voltage detection circuit 12 is equal to or higher than a predetermined voltage value γ, and When the detected current of the current detecting circuit 11 is equal to or less than a predetermined current value β, the discharge state determining means for determining that the discharge of the high-pressure discharge lamp 6 is abnormal, and the driving of the inverter 5 when the discharge state determining means determines that the discharge is abnormal. There is provided a discharge control means for stopping and turning off the high-pressure discharge lamp 6, and after a lapse of a predetermined time Tg, restarting the inverter 5 to re-discharge the high-pressure discharge lamp 6.

Here, the operation of the control circuit will be described in detail with reference to FIGS. FIG. 2 is a flowchart showing the operation of the control circuit according to the first embodiment, and FIG. 3 is a flowchart of the timer time Tg for stopping the inverter. When a control power supply is turned on by turning on a lighting switch (not shown), the control circuit 13 starts driving the active filter 3 and controls the output voltage to be a predetermined voltage (S1). Then, the timer time Tg for stopping the inverter is set to zero, and it is determined whether or not the timer time Tg is zero (S2, S3).
At this time, since it is zero, the inverter 5 is driven to apply a low-frequency AC voltage to the high-pressure discharge lamp 6, and the high-voltage pulse generating circuit 7 is driven to apply a high-voltage pulse (S4, S5). Then, the high-pressure discharge lamp 6 is discharged. At this time,
The current flowing through the high-pressure discharge lamp 6 (hereinafter, referred to as “discharge lamp current A”) is read from the current detection circuit 11 (S6) and compared with a predetermined value α (S7).

When the discharge lamp current A is less than the predetermined value α, the high voltage pulse generation circuit 7 is continuously driven to
(S5, S6). When the discharge lamp current A becomes equal to or more than the predetermined value α by repeating this execution, the detection voltage of the voltage detection circuit 12 (hereinafter, referred to as “discharge lamp voltage VL”).
Is read (S8), and then the discharge lamp current IL is read through the current detection circuit 11 (S9). Then, first, the discharge lamp voltage VL is compared with a predetermined voltage value γ (S10). If the discharge lamp voltage VL is less than the voltage value γ, it is determined that the discharge has started normally, and the discharge lamp voltage VL is determined. The target current IM is calculated (S11). When the discharge lamp voltage VL is equal to or higher than the voltage value γ, the read lamp current IL is compared with a predetermined current value β (S12). When the current value β is exceeded, the target current IM is calculated from the discharge lamp voltage VL in the same manner as described above (S11), the result is set in the differential amplifier circuit 10, and the discharge lamp voltage VL and the discharge lamp current are again set. It starts reading IL (S8, S9). At this time, the differential amplifier circuit 10 drives the current limiting circuit 4 so that the detection current of the current detection circuit 11 becomes equal to the target current IM.

On the other hand, if the read discharge lamp voltage VL is equal to or higher than the predetermined voltage value γ and the discharge lamp current IL is equal to or lower than the predetermined current value β, it is determined that abnormal discharge has occurred and the value λ Is set as the time Tg for stopping the inverter, and the driving of the inverter 5 is stopped to turn off the high-pressure discharge lamp 6 (S13, S14). Then, it waits until the set time Tg becomes zero (S3). This standby is for sufficiently cooling the high-pressure discharge lamp 6, and the countdown is performed at predetermined time intervals until the time Tg becomes zero (S21 to S2).
3). When the counted time Tg becomes zero by the countdown, the inverter 5 is driven again to apply a low-frequency AC voltage to the high-pressure discharge lamp 6 (S4), and then the high-voltage pulse generating circuit 7 is driven to generate a high-voltage pulse. (S5) to discharge the high pressure discharge lamp 6.

As described above, according to the first embodiment, when the discharge lamp voltage VL is equal to or more than the predetermined voltage value γ and the discharge lamp current IL is equal to or less than the predetermined current value β, the discharge of the high-pressure discharge lamp 6 is abnormal. When it is determined that the discharge is abnormal, the drive of the inverter 5 is stopped and the high-pressure discharge lamp 6 is turned off.
Since the high-pressure discharge lamp 6 is re-discharged, the high-pressure discharge lamp 6 does not continue to be lit with abnormal discharge, thereby shortening the life of the high-pressure discharge lamp 6 due to the lighting in the abnormal discharge state. Can be prevented.

Embodiment 2 FIG. In the second embodiment, the control circuit 13 determines that the discharge lamp voltage VL read from the voltage detection circuit 12 is equal to or higher than a predetermined voltage value γ and that the current detection circuit 11
Discharge state determining means for determining that the discharge of the high-pressure discharge lamp 6 is abnormal when the detected discharge lamp current IL is equal to or less than a predetermined current value β,
A discharge control means for causing the current flowing to the high-pressure discharge lamp 6 to flow more than usual when the discharge state determination means determines that the discharge is abnormal; for example, when an abnormal discharge occurs in the high-pressure discharge lamp 6, The current δ is added to the current value obtained from the voltage VL.
Is set in the differential amplifier circuit 10 as a target current IM.

Here, the operation of the control circuit according to the second embodiment will be described in detail with reference to FIG. FIG. 4 is a flowchart illustrating the operation of the control circuit according to the second embodiment. When the control power supply rises, the control circuit 13 starts the operation of the active filter 3 as described above to control the output voltage to a predetermined voltage (S31), and then drives the inverter 5 to drive the low-frequency AC. A voltage is applied to the high-pressure discharge lamp 6, and the high-voltage pulse generating circuit 7 is driven to apply a high-voltage pulse (S32, S33), thereby discharging the high-pressure discharge lamp 6. At this time, the discharge lamp current A is read via the current detection circuit 11 (S34), and is compared with a predetermined value α (S3).
5). When the discharge lamp current A is less than the predetermined value α, the high voltage pulse generation circuit 7 is continuously driven to start reading the discharge lamp current A (S33, S34). If it exceeds α, the discharge lamp voltage
The VL and the discharge lamp current IL are read from the detection circuits 11 and 12 (S36, S37).

Then, first, the discharge lamp voltage VL is compared with a predetermined voltage value γ (S38).
If it is less than the predetermined value, it is determined that the discharge has started normally,
In step S40, the discharge lamp voltage VL is equal to or higher than the predetermined voltage value γ, and the discharge lamp current IL is compared with the predetermined current value β (S40). When the discharge lamp current IL exceeds the current value β, the calculation of the target current IM starts in the same manner as described above (S39). When the discharge lamp current IL is equal to or less than the predetermined current value β, abnormal discharge occurs. Is determined as the target current IM (S41), and a value obtained by adding the current δ to the current value obtained from the discharge lamp voltage VL is set in the differential amplifier circuit 10. Next, the process returns to S36 to start reading the discharge lamp voltage VL.

On the other hand, the differential amplifier circuit 10 drives the current limiting circuit 4 so as to obtain the target current IM set by the control circuit. Therefore, in the high-pressure discharge lamp 6, the discharge path of the abnormal discharge is used. , The energy level is lower between the electrode tips, and the abnormal discharge shifts between the electrode tips to become a normal discharge.

In the second embodiment, when the discharge lamp voltage VL is equal to or higher than a predetermined voltage value γ and the discharge lamp current IL is equal to or lower than a predetermined current value β, the discharge of the high-pressure discharge lamp 6 is determined to be abnormal. When the discharge is determined, the value obtained by adding the current δ to the current value obtained from the discharge lamp voltage VL is set as the target current IM in the differential amplifier circuit 10 so that the current flows through the high-pressure discharge lamp 6. Therefore, even if an abnormal discharge occurs in the high-pressure discharge lamp 6, the abnormal discharge can be immediately eliminated, and the high-pressure discharge lamp 6 does not continue to be lit with the abnormal discharge. There is an effect that it is possible to prevent shortening.

Embodiment 3 FIG. In the third embodiment, when the control circuit 13 determines that the discharge of the high-pressure discharge lamp 6 is abnormal when the discharge lamp voltage VL detected by the voltage detection circuit 12 is equal to or higher than a predetermined voltage value γ for a predetermined time T1. When the determination unit and the discharge state determination unit determine that the discharge is abnormal, the driving of the inverter 5 is stopped to turn off the high-pressure discharge lamp 6, and a predetermined time period.
After the lapse of Tg, the inverter 5 is restarted and its high-pressure discharge lamp 6
And a discharge control means for discharging again.

Next, the operation of the control circuit having the above means will be described in detail. FIG. 5 is a flowchart showing the operation of the control circuit according to the third embodiment, and FIG. 6 is a flowchart of the time T1 when the discharge lamp voltage VL becomes equal to or higher than a predetermined voltage value γ. The operations from S51 to S57 are the same as the operations from S1 to S7 in FIG.

When the discharge lamp current A read from the current detection circuit 11 exceeds a predetermined value α, the control circuit 13 reads the discharge lamp voltage VL detected by the voltage detection circuit 12 (S5).
8) Compare with a predetermined voltage value γ (S59). If the discharge lamp voltage VL is lower than the voltage value γ, it is determined that the discharge has started normally, the value K is set as the time T1, and the target current IM is calculated from the discharge lamp voltage VL (S6).
0, S61). Then, the result is set in the differential amplifier circuit 10 to drive the output current of the current limiting circuit 4 to the target current IM, and the discharge lamp voltage VL is read again (S5).
8). When steps S58 to S61 are repeatedly executed, the value K is set each time as the clock time T1, so that the time is kept set without counting down the clock time T1.

If the read discharge lamp voltage VL is equal to or higher than the predetermined voltage value γ, the time set in S60 is counted.
It is determined whether T1 is zero (S62). Discharge lamp voltage VL
Since the measured time T1 does not become zero at the time when the voltage becomes equal to or more than the predetermined voltage value γ, the process proceeds to S61, and the target current IM is calculated from the discharge lamp voltage VL as described above. It is set to 10 and reading of the discharge lamp voltage VL is started again (S58). When S58, S59, S62 and S61 are repeatedly executed, the counted time T1 is counted down every predetermined time (S91, S92), and when the counted time becomes zero by the countdown, the counted time T1 is set to zero ( S93).

On the other hand, S5 until the time T1 becomes zero.
8, S59, S62, and S61 are repeatedly performed, it is determined that abnormal discharge has occurred in the high-pressure discharge lamp 6, and
The value λ is set as the time Tg for stopping the inverter, and the driving of the inverter 5 is stopped (S63, S64),
The high pressure discharge lamp 6 is turned off.

Then, as described in the first embodiment, the control waits until the clock time Tg becomes zero (S53), and the clock time Tg
Becomes zero, the inverter 5 is driven again to apply a low-frequency AC voltage to the high-pressure discharge lamp 6 (S54), and then the high-voltage pulse generating circuit 7 is driven to apply a high-voltage pulse. (S55), the high pressure discharge lamp 6 is discharged.

In the third embodiment, during the time T1, the discharge of the high-pressure discharge lamp 6 is determined to be abnormal when the discharge lamp voltage VL is equal to or higher than the predetermined voltage value γ, and when the discharge is determined to be abnormal, the inverter 5 Is stopped, the high-pressure discharge lamp 6 is turned off, and after a lapse of time Tg, the high-pressure discharge lamp 6 is re-discharged. Therefore, it is possible to prevent the life of the high-pressure discharge lamp 6 from being shortened due to the lighting in the abnormal discharge state.

Embodiment 4 FIG. In the fourth embodiment, the control circuit 13 determines that the discharge of the high-pressure discharge lamp 6 is abnormal when the discharge lamp voltage VL detected by the voltage detection circuit 12 is equal to or higher than a predetermined voltage value γ for a predetermined time T1. The high-pressure discharge lamp 6 is provided with a determination unit and a discharge control unit that causes the current flowing through the high-pressure discharge lamp 6 to flow more than usual when the discharge state determination unit determines that the discharge is abnormal. When this occurs, a value obtained by adding the current δ to the current value obtained from the discharge lamp voltage VL is set in the differential amplifier circuit 10 as the target current IM.

Here, the operation of the control circuit having the above means will be described in detail. FIG. 7 is a flowchart illustrating the operation of the control circuit according to the fourth embodiment. The operations of S71 to S75 are the same as those of S31 to S35 of FIG.
The operations from S76 to S80 are the same as the operations from S58 to S62 in FIG.
Since the operation is the same as that described above, the description is omitted.

When the discharge lamp voltage VL read from the voltage detection circuit 12 is less than the predetermined voltage value γ, the control circuit 13 determines that the discharge is performed normally and repeats steps S76 to S79. , The read discharge lamp voltage VL is equal to or higher than the predetermined voltage value γ, and the time T1 set in S78.
Is not zero, S76, S77, S80, S79
Is repeatedly executed. When this operation is repeated, the countdown time T1 is counted down every predetermined time (see FIG. 6), and when the countdown time T1 becomes zero,
It is determined that abnormal discharge has occurred in the high-pressure discharge lamp 6, and a value obtained by adding the current δ to the current value obtained from the discharge lamp voltage VL is set as the target current IM (S81) and set in the differential amplifier circuit 10. To start reading the discharge lamp voltage VL (S76).

If the read discharge lamp voltage VL is equal to or higher than the predetermined voltage value γ, the time T1 is zero, so that the target current IM is continuously calculated in S81 and the differential amplifier 1
When the discharge lamp voltage VL becomes less than the predetermined voltage value γ based on the target current IM calculated in S81, it is determined that the discharge is normal, and S76 to S79 are repeatedly executed.

As described above, during the time T1, the discharge of the high-pressure discharge lamp 6 is determined to be abnormal when the discharge lamp voltage VL is equal to or higher than the predetermined voltage value γ, and when the discharge lamp voltage VL is determined to be abnormal discharge.
The value obtained by adding the current δ to the current value obtained from
Is set in the differential amplifier circuit 10 and the current is caused to flow through the high-pressure discharge lamp 6, so that even if an abnormal discharge occurs in the high-pressure discharge lamp 6, it can be immediately eliminated, and the high-pressure discharge lamp 6 is turned on with the abnormal discharge Therefore, it is possible to prevent the life of the high-pressure discharge lamp 6 from being shortened due to the lighting in the abnormal discharge state.

Embodiment 5 In the fifth embodiment, when the discharge lamp current IL read from the current detection circuit 11 continues for a predetermined time T2 and is equal to or less than a predetermined current value β, the control circuit 13 determines that the discharge of the high-pressure discharge lamp 6 is abnormal. When the determination means and the discharge state determination means determine that the discharge is abnormal, the driving of the inverter 5 is stopped and the high-pressure discharge lamp 6 is turned off.
After a lapse of a predetermined time Tg, a discharge control means for restarting the inverter 5 and re-discharging the high-pressure discharge lamp 6 is provided.

Next, the operation of the control circuit having the above means will be described in detail. FIG. 8 is a flowchart showing the operation of the control circuit according to the fifth embodiment, and FIG. 9 is a flowchart of the time T2 when the discharge lamp current IL becomes equal to or more than a predetermined current value β. The operations from S101 to S109 are the same as the operations from S1 to S9 in FIG.

When the control circuit 13 reads the discharge lamp current IL from the current detection circuit 11, it compares it with a predetermined current value β (S110). When the discharge lamp current IL is larger than the current value β, it is determined that the discharge is performed normally, and the value K is set as the clocking time T2 and the discharge lamp voltage VL read through the voltage detection circuit 12 is used. Calculate the target current IM (S
111, S112). Then, the result is set in the differential amplifier circuit 10 and driven so that the output current of the current limiting circuit 4 becomes the target current IM, and again the discharge lamp voltage VL and the discharge lamp current IL
(S108, S109). This S10
In the case where steps 8 to S112 are repeatedly executed, the value K is set each time as the clocking time T2 as described above, so that the clocking time T2 remains set.

If the read discharge lamp current IL is equal to or smaller than the predetermined current value β, it is determined whether the time T2 set in S111 is zero (S113). When the discharge lamp current IL becomes equal to or less than the predetermined current value β, the timer time T2 does not become zero, so the process proceeds to S112, and the target current IM is calculated from the discharge lamp voltage VL as described above. The discharge lamp voltage VL and the discharge lamp current are set in the differential amplifier circuit 10 again.
The reading of IL starts (S108, S109). This S1
When the steps 08, S109, S110, S113 and S112 are repeatedly executed, the counted time T2 is counted down every predetermined time (S141, S142), and when the counted time becomes zero by the countdown, the counted time T2 is set to zero. (S143).

On the other hand, S10 until the time T2 becomes zero.
8, when S109, S110, S113, and S112 are repeatedly executed, it is determined that abnormal discharge has occurred in the high-pressure discharge lamp 6, and the value λ is set as the inverter stoppage time Tg. Stop driving (S
114, S115), the high pressure discharge lamp 6 is turned off.

Then, as described in the first embodiment, the control waits until the clock time Tg becomes zero (S103).
When Tg becomes zero, the inverter 5 is driven again to apply a low-frequency AC voltage to the high-pressure discharge lamp 6 (S10).
4) Then, the high-voltage pulse generating circuit 7 is driven to apply a high-voltage pulse (S105), and the high-pressure discharge lamp 6 is discharged.

As described above, according to the fifth embodiment, the time T2
During the period, when the discharge lamp current IL is equal to or less than the predetermined current value β, the discharge of the high-pressure discharge lamp 6 is determined to be abnormal, and when the discharge is determined to be abnormal, the drive of the inverter 5 is stopped to stop the high-pressure discharge lamp 6. Since the high-pressure discharge lamp 6 is turned off and the high-pressure discharge lamp 6 is re-discharged after the elapse of the time Tg, the high-pressure discharge lamp 6 does not continue to be lit with abnormal discharge. There is an effect that it is possible to prevent the life of the lamp 6 from being shortened.

Embodiment 6 FIG. In the sixth embodiment, the control circuit 13 determines that the discharge of the high-pressure discharge lamp 6 is abnormal when the discharge lamp current IL read from the current detection circuit 11 is equal to or less than a predetermined current value β for a predetermined time T2. The apparatus includes a determination unit and a discharge control unit that causes the current flowing through the high-pressure discharge lamp 6 to flow more than usual when abnormal discharge is determined by the discharge state determination unit.

Here, the operation of the control circuit having the above means will be described in detail. FIG. 10 is a flowchart illustrating the operation of the control circuit according to the sixth embodiment. Note that S121 to S1
The operations up to 27 are described in S31 to S31 in FIG.
Since the operation is the same as the operation up to S37, S128 to S1
The operations up to 31 are the same as those of S110 of FIG.
Since the operation is the same as that of S113, the description is omitted.

When the discharge lamp current IL read from the current detection circuit 11 is larger than the predetermined current value β, the control circuit 13 determines that the discharge is normally performed and determines in steps S126 to S126.
The steps up to 130 are repeatedly executed. If the read discharge lamp current IL is equal to or smaller than the predetermined current value β and the time T2 set in S129 is not zero, S126 and S12 are executed.
7, S128, S131, and S130 are repeatedly executed. When this operation is repeatedly performed, as described above, the countdown is performed at predetermined time intervals until the clock time T2 becomes zero (see FIG. 9). When the clock time T2 becomes zero, the high pressure discharge lamp 6 becomes abnormal. It is determined that discharge has occurred, and a value obtained by adding the current δ to the current value obtained from the discharge lamp voltage VL is set as the target current IM (S132), and set in the differential amplifier circuit 10 to set the discharge lamp voltage VL and The process starts reading the discharge lamp current IL (S126, S127).

When the discharge lamp current IL is equal to or smaller than the predetermined current value β, the target current IM is continuously calculated in S132 and set in the differential amplifier circuit 10, and the discharge lamp current IL becomes larger than the predetermined current value β. When it is determined that the discharge has become normal, steps S126 to S130 are repeatedly executed.

As described above, during the time T2, when the discharge lamp current IL is equal to or less than the predetermined current value β, the discharge of the high-pressure discharge lamp 6 is determined to be abnormal, and when the discharge is determined to be abnormal, the discharge lamp voltage is determined.
The value obtained by adding the current δ to the current value obtained from VL is the target current
Since the current is set in the differential amplifier circuit 10 as IM and the current flows to the high-pressure discharge lamp 6, even if an abnormal discharge occurs in the high-pressure discharge lamp 6, it can be immediately eliminated, and the high-pressure discharge lamp 6 remains in the abnormal discharge state. It will no longer stay lit,
There is an effect that it is possible to prevent the life of the high-pressure discharge lamp 6 from being shortened by lighting in the abnormal discharge state.

Embodiment 7 In the seventh embodiment, the control circuit 13 determines whether or not the discharge lamp current A detected by the current detection circuit 11 is equal to or greater than a predetermined value α.
Is smaller than the predetermined value α, the discharge state judging means for judging that the discharge of the high-pressure discharge lamp 6 is abnormal, and the inverter 5 and the high-voltage pulse generation circuit 7 When the set pause time is inserted and intermittent drive is performed, and the intermittent drive is repeated a predetermined number of times without the detected current being equal to or more than the predetermined value α, the pause time is set to be long and the inverter 5 and the high voltage Control means for intermittently driving the pulse generation circuit 7.

Next, the operation of the control circuit having the above means will be described in detail. 11 is a flowchart showing the operation of the control circuit according to the seventh embodiment, FIG. 12 is a flowchart of the time Ta of the pulse width of the high-voltage pulse, FIG. 13 is a flowchart of the time Tb of the pause of the high-voltage pulse, and FIG. It is a waveform diagram of a voltage pulse.

When the control power supply rises by turning on the lighting switch, the control circuit 13 sets the count value C of the high voltage pulse output from the high voltage pulse generation circuit 7 to zero (S151), and sets the value κ to the high voltage. The time is set as the time Ta of the pulse width of the pulse (S152). Then, the operation of the active filter 3 is started to control the output voltage to a predetermined voltage (S153), and the inverter 5 is driven to apply a low-frequency AC voltage to the high-pressure discharge lamp 6 and generate a high-voltage pulse. The circuit 7 is driven to apply a high voltage pulse (S154, S155), and the high pressure discharge lamp 6 is discharged.
At this time, the discharge lamp current A flowing through the high-pressure discharge lamp 6 is read from the current detection circuit 11 (S156), and is compared with a predetermined value α (S157).

When the discharge lamp current A is equal to or larger than the predetermined value α, it is determined that the discharge has been normally performed, the discharge lamp voltage VL is read, and the calculation of the target current IM is started (S158, S15).
9) If the discharge lamp current A is less than the predetermined value α, it is determined whether the time Ta of the pulse width is zero (S160).
The time Ta is counted down every predetermined time as shown in FIG. 12 (S171, S172), and when the countdown becomes zero by the countdown, the time Ta is set to zero (S173).

At S160, the time Ta of the pulse width is measured.
Is not zero, that is, when the high-voltage pulse is being applied to the high-pressure discharge lamp 6, the driving of the high-voltage pulse generation circuit 7 is continued to start reading the discharge lamp current A (S155), and the time Ta of the pulse width is measured. Becomes zero, that is, the discharge lamp current A
When the application of the high-voltage pulse is completed without exceeding the predetermined value α, it is determined that the discharge has failed, and the driving of the inverter 5 and the high-voltage pulse generation circuit 7 is stopped (S161, S1).
62), the count value C of the high voltage pulse and the preset value μ
Are compared (S163). This value μ is the time Tb described later.
This is the number of high-voltage pulses output every time (see FIG. 14). When the count value C is equal to or more than the value μ, the process proceeds to S165. When the count value C is less than the value μ, the value λ is set to the high voltage. It is selected as the time Tb of the pause of the pulse (S164).

Then, the process waits until the time Tb becomes zero (S166). This time Tb is counted down every predetermined time as shown in FIG.
In step S182), when the countdown reaches zero, the timer Tb is set to zero (S183). Clocking time
When Tb becomes zero, the count value C is counted up (S1).
67), and compares it with a preset total value μ ₀ of high voltage pulses (S168). At this point, since the count value C does not reach the total value μ ₀ , the process proceeds to S152, and the value κ is set again as the time Ta of the pulse width of the high-voltage pulse, and the above-described series of operations is executed.

Before the count value C of the high-voltage pulse output every pause time Tb (= λ) becomes equal to or more than the value μ, the discharge lamp current A
Is greater than or equal to the predetermined value α, it is determined that the discharge is normal, and the calculation of the target current IM is started (S158, S15).
9) When the count value C of the high-voltage pulse is not less than the value μ without the discharge lamp current A being not less than the predetermined value α, FIG.
The value λ + ρ is calculated as shown in
It is selected as Tb (S165). Then, as described above, the process waits until the time Tb becomes zero (S166).
Counts up the count value C when the measured time Tb is zero (S167), compares the total value mu ₀ of the high voltage pulse that is set in advance (S168). At the time of switching of the clock time Tb, the count value C does not reach the total value μ ₀ , so the process proceeds to S152, sets the value κ as the clock time Ta of the pulse width of the high-voltage pulse, and executes the above-described series of operations. .

If the discharge lamp current A exceeds the predetermined value α before the count value C of the high-voltage pulse output for each pause Tb (= λ + ρ) exceeds the total value μ ₀ , the discharge is normal. And the calculation of the target current IM is started (S158,
S159), when the discharge lamp current A is the count value C of the high-voltage pulse without being more than the predetermined value α becomes sum mu ₀ or stops the active filter 3 (S169), the apparatus completely Stop.

As described above, in the seventh embodiment, when the high-pressure discharge lamp is turned on, if the discharge lamp current A read from the current detection circuit 11 is less than the predetermined value α, the discharge of the high-pressure discharge lamp 6 is determined to be abnormal, and When the discharge is determined, the driving of the inverter 5 and the high-voltage pulse generating circuit 7 is stopped for the time Tb, the high-pressure discharge lamp 6 is cooled and then driven again, and the discharge lamp current A does not exceed the predetermined value α. When the intermittent driving is repeated a predetermined number of times μ, that is, when the discharge of the high-pressure discharge lamp 6 does not become normal, the time Tb is set long to drive the inverter 5 and the high-voltage pulse generating circuit 7 intermittently. Since the high-pressure discharge lamp is further cooled, abnormal discharge does not occur at the time of re-lighting, so that the high-pressure discharge lamp 6 does not continue to be lit with abnormal discharge.
There is an effect that it is possible to prevent the life of the high-pressure discharge lamp 6 from being shortened by lighting in the abnormal discharge state.

[0055]

As described above, according to the present invention, when the detection voltage of the voltage detection circuit is equal to or higher than the predetermined voltage value and the detection current of the current detection circuit is equal to or lower than the predetermined current value, the discharge of the high-pressure discharge lamp is performed. Is determined to be abnormal, and when it is determined that the discharge is abnormal, the high-pressure discharge lamp is turned off and the high-pressure discharge lamp is restarted after a predetermined time Tg has elapsed. Therefore, there is an effect that it is possible to prevent the life of the high pressure discharge lamp from being shortened due to the lighting in the abnormal discharge state.

The detection voltage of the voltage detection circuit is set for a predetermined time.
When the voltage of the high-pressure discharge lamp is determined to be abnormal when T1 is continuously higher than the predetermined voltage value, the high-pressure discharge lamp is turned off when the abnormal discharge is determined, and the high-pressure discharge lamp is restarted after a lapse of a predetermined time Tg. As a result, the high pressure discharge lamp does not continue to be lit while the abnormal discharge is occurring, and therefore, it is possible to prevent the life of the high pressure discharge lamp from being shortened due to the lighting in the abnormal discharge state.

Further, when the detected current of the current detecting circuit continues for a predetermined time T2 and is equal to or less than a predetermined current value, the discharge of the high pressure discharge lamp is determined to be abnormal, and when it is determined that the discharge is abnormal, the high pressure discharge lamp is turned off. After the predetermined time Tg has elapsed, the high-pressure discharge lamp is restarted, so that the high-pressure discharge lamp does not continue to be lit with abnormal discharge. There is an effect that shortening can be prevented.

Further, when the discharge state determination means determines that the discharge is abnormal, the current flowing through the high-pressure discharge lamp is made to flow more than usual, so that even if an abnormal discharge occurs in the high-pressure discharge lamp, it can be immediately eliminated. The high pressure discharge lamp does not continue to be lit with the abnormal discharge, and therefore, it is possible to prevent the life of the high pressure discharge lamp from being shortened due to the lighting in the abnormal discharge state.

The current detected by the current detecting circuit is a predetermined value α.
If the detected current is less than the predetermined value α, it is determined that the discharge of the high-pressure discharge lamp is abnormal, and if it is determined that the discharge is abnormal, a pause set in advance for driving the inverter and the high-voltage generating circuit is determined. When the intermittent driving is performed by inserting a time and the intermittent driving is repeated a predetermined number without the detected current being equal to or more than the predetermined value α, the pause time is set long to intermittently drive the inverter and the high voltage generation circuit. As a result, abnormal discharge does not occur at the time of re-lighting,
It is possible to prevent the high pressure discharge lamp from being continuously lit with the abnormal discharge, thereby preventing the life of the high pressure discharge lamp from being shortened due to the lighting in the abnormal discharge state.

[Brief description of the drawings]

FIG. 1 is a block diagram of a high pressure discharge lamp lighting device according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of a control circuit according to the first embodiment.

FIG. 3 is a flowchart of a timer time Tg for stopping the inverter.

FIG. 4 is a flowchart illustrating an operation of a control circuit according to the second embodiment.

FIG. 5 is a flowchart illustrating an operation of a control circuit according to the third embodiment.

FIG. 6 is a flowchart of a clock time T1 when the discharge lamp voltage VL becomes equal to or higher than a predetermined voltage value γ.

FIG. 7 is a flowchart illustrating an operation of a control circuit according to the fourth embodiment.

FIG. 8 is a flowchart illustrating an operation of a control circuit according to the fifth embodiment.

FIG. 9 is a flowchart of a clocking time T2 when the discharge lamp current IL becomes equal to or more than a predetermined current value β.

FIG. 10 is a flowchart illustrating an operation of a control circuit according to the sixth embodiment.

FIG. 11 is a flowchart illustrating an operation of a control circuit according to a seventh embodiment.

FIG. 12 is a flowchart of a time Ta for measuring a pulse width of a high-voltage pulse.

FIG. 13 is a flowchart of a time interval Tb of suspension of a high-voltage pulse.

FIG. 14 is a waveform diagram of a high-voltage pulse.

FIG. 15 is an explanatory diagram of normal discharge of a high-pressure discharge lamp.

FIG. 16 is an explanatory diagram of abnormal discharge of a high-pressure discharge lamp.

[Description of Signs] 1 Commercial power supply, 2 Full-wave rectifier circuit, 3 Active filter, 4 Current limiting circuit, 5 Inverter, 6
High pressure discharge lamp, 7 high voltage pulse generation circuit, 8 control power supply circuit, 9 active filter output voltage detection circuit,
10 differential amplifier circuit, 11 current detection circuit, 12
Voltage detection circuit, 13 control circuit.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroyasu Private City 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (5)

[Claims] 1. A high-pressure discharge lamp, an inverter that converts a DC voltage to a low-frequency AC voltage and supplies the low-voltage AC voltage to the high-pressure discharge lamp, and a high-voltage generator that generates a high voltage for starting the high-pressure discharge lamp. A voltage generation circuit, a voltage detection circuit that detects a voltage supplied to the high-pressure discharge lamp, a current detection circuit that detects a current flowing through the high-pressure discharge lamp, and the detection voltage is equal to or higher than a predetermined voltage value, and Discharge state determining means for determining that the discharge of the high-pressure discharge lamp is abnormal when the detected current is equal to or less than a predetermined current value; turning off the high-pressure discharge lamp when the discharge state determination means determines that the discharge is abnormal; A high-pressure discharge lamp lighting device comprising: discharge control means for restarting the high-pressure discharge lamp after a lapse of Tg. 2. A high-pressure discharge lamp, an inverter that converts a DC voltage into a low-frequency AC voltage and supplies the low-voltage AC voltage to the high-pressure discharge lamp, and a high-voltage generator that generates a high voltage for starting the high-pressure discharge lamp. A voltage generation circuit, a voltage detection circuit that detects a voltage supplied to the high-pressure discharge lamp, and a discharge that determines that the discharge of the high-pressure discharge lamp is abnormal when the detected voltage is equal to or higher than a predetermined voltage value for a predetermined time T1 continuously. State determination means, and discharge control means for turning off the high-pressure discharge lamp when the discharge state determination means determines abnormal discharge, and restarting the high-pressure discharge lamp after a predetermined time Tg has elapsed. High pressure discharge lamp lighting device. 3. A high-pressure discharge lamp, an inverter that converts a DC voltage to a low-frequency AC voltage and supplies the low-voltage AC voltage to the high-pressure discharge lamp, and a high-voltage generator that generates a high voltage for starting the high-pressure discharge lamp. A voltage generation circuit, a current detection circuit that detects a current flowing through the high-pressure discharge lamp, and a discharge state determination that determines that the discharge of the high-pressure discharge lamp is abnormal when the detected current is continuously equal to or less than a predetermined current value for a predetermined time T2. And a discharge control means for turning off the high-pressure discharge lamp when an abnormal discharge is determined by the discharge state determination means and restarting the high-pressure discharge lamp after a lapse of a predetermined time Tg. Discharge lamp lighting device. 4. The discharge control unit according to claim 1, wherein when the discharge state determination unit determines that the discharge is abnormal, a current flowing through the high-pressure discharge lamp flows more than usual.
3. The high pressure discharge lamp lighting device according to any one of 3. 5. A high-pressure discharge lamp, an inverter that converts a voltage converted to direct current into a low-frequency alternating voltage and supplies the low-voltage alternating voltage to the high-pressure discharge lamp, and a high-voltage generator that generates a high voltage for starting the high-pressure discharge lamp. A voltage generation circuit, a current detection circuit for detecting a current flowing through the high-pressure discharge lamp, and determining whether the detected current is equal to or more than a predetermined value α, and discharging the high-pressure discharge lamp when the detected current is less than the predetermined value α. A discharge state determining means for determining that an abnormal discharge has occurred, and when the discharge state determining means has determined that an abnormal discharge has occurred, a predetermined pause time is inserted into the drive of the inverter and the high voltage generation circuit to perform intermittent drive, and the detection is performed. When the intermittent driving is repeated a predetermined number of times without the current exceeding the predetermined value α, the intermittent driving is set to be long, and a control means for intermittently driving the inverter and the high voltage generating circuit is provided. High pressure discharge lamp lighting device according to.