JP4651736B2 - High pressure discharge lamp lighting device - Google Patents

Description

  The present invention relates to a safe high-pressure discharge lamp lighting device that accurately avoids discharge in an outer tube of a high-pressure discharge lamp such as a mercury lamp, a metal halide lamp, or a high-pressure sodium lamp.

  In general, high-pressure discharge lamps such as mercury lamps, metal halide lamps, high-pressure sodium lamps, and the like become unstable at the end of their lives, resulting in a decrease in luminous flux, and problems such as extinction. As shown in FIG. 13, in the conventional high-pressure discharge lamp, when the discharge lamp being turned on is extinguished and immediately after a short time, a pulse is applied by entering the restart mode immediately after a short time. (Inner tube) could not be discharged, and the possibility of discharge in the outer tube was high. If a discharge occurs between the lead wires in the outer tube, a large current flows, which may break the outer tube or destroy the inverter.

  When the high-pressure discharge lamp is turned off from the state of stable lighting, the arc tube of the high-pressure discharge lamp is very hot and high pressure immediately after it is turned off. After that, it is known that the arc tube temperature of the high-pressure discharge lamp decreases with time and the dielectric breakdown voltage also decreases.

  Thus, the high pressure discharge lamp needs to apply a high voltage of several kv to several tens of kv at the start, and is configured to repeat the start when the start fails. When it is difficult to start due to a failure or a life, a high voltage may be repeatedly generated for a long time, which may damage the lighting device or cause an electric shock.

  Therefore, for the purpose of providing a discharge lamp that is less likely to damage or cause an electric shock to a lighting device or the like, as shown in FIG. 14, a power supply unit 101 that supplies power to the discharge lamp 103, and a discharge lamp The high voltage generator 102 for starting which supplies the high voltage for starting to 103, the electric current detection means 104 which detects the electric current supplied to the discharge lamp 103, the state of the discharge lamp 103, and the electric power feeding part 101 and start A monitoring control unit 105 for controlling the high voltage generating unit 102. The monitoring control unit 105 first drives the starting high voltage generating unit 102 at the time of starting, and monitors the starting state by the output of the current detecting unit 104. In the case of failure in starting, the sequence of driving the starting high voltage generating means 102 again and monitoring the starting state by the output of the current detecting means 104 is repeated up to a predetermined number of times, and When the over there is a discharge lamp lighting device to stop the feeding by the feeding unit 101 stops the driving of the starting high voltage generating unit 102 (e.g., see Patent Document 1).

  In general, the discharge lamp is connected to a lighting device via a connection terminal for the purpose of lamp replacement. If the contact state by the connection terminal is insufficient, the following problems occur. Even if the discharge lamp is in a contact state in which the discharge lamp can be lit at the start immediately after the AC power supply is turned on, the contact state may become defective during the lighting and the discharge lamp may go out. Immediately after the discharge lamp is extinguished, ions remain between the electrodes of the discharge lamp, and it takes about several tens of milliseconds to disappear. If a high voltage pulse is applied before the disappearance of residual ions, if the contact state of the connection terminal is insufficient, the lighting state will not be reached and a slight discharge will start, and this fine discharge will continue and current will flow to the connection terminal. Will continue. When such a current flows, an electrical stress on the connection terminal increases, and ignition and smoke may occur. Therefore, when the residual ions in the discharge lamp disappear at the time of restart, a high voltage pulse is generated to prevent the discharge lamp from generating a slight discharge, so that no large electrical stress is applied to the connection terminals. There is an electric lighting device.

FIG. 15 is a circuit diagram of a discharge lamp lighting device including a start pulse generation circuit 7 that starts a discharge lamp by superimposing a high voltage pulse on a power supply voltage. In the figure, the starting pulse generation circuit 7 includes a series circuit of a pair of resistors R1 and R2 connected between both ends of the AC power supply AC, a capacitor C1 connected in parallel to the resistor R2, and a primary winding N1 of the ballast L. Capacitor C2 and switching element Q1 (for example, triac) connected in series to each other, and a voltage-responsive trigger element Q2 connected between the connection point of both resistors R1 and R2 and the control terminal (gate) of the switching element Q1 (For example, a diac) and a resistor R3. Therefore, when the voltage obtained by dividing the voltage of the AC power supply AC as shown in FIG. 16A by the resistors R1 and R2 exceeds the breakover voltage of the trigger element Q2, the trigger element Q2 is turned on and the resistance R3 passes through the resistor R3. A current flows through the control terminal of the switching element Q1. Then, the switching element Q1 is turned on, and a charging current Ic as shown in FIG. 16B flows from the AC power supply AC to the capacitor C2 through the primary winding N1 of the ballast L. When the capacitor C2 is charged, the charging current stops and the switching element Q1 is turned off. A charging current Ic for the capacitor c2 flows through the ballast L from the time when the switching element Q1 is turned on at time t1 to the time when the switching element Q2 is turned off at time t2. This charging current Ic flows every half cycle of the AC power supply AC. Since the charging current Ic to the capacitor c2 flows through the primary winding N1 of the ballast L, a voltage obtained by boosting the voltage applied to the primary winding N1 is generated in the secondary winding N2 of the ballast L. A high voltage pulse is generated in the secondary winding N2 of the ballast L, and this high voltage pulse is superimposed on the voltage of the AC power supply AC, whereby a voltage V _DL as shown in FIG. 16C is applied to the discharge lamp DL. Applied. In this way, the discharge lamp DL is started by applying a high voltage to the discharge lamp DL.

  Since it is not necessary to generate a high voltage pulse when the discharge lamp DL is lit, the lighting discrimination circuit OC detects that the discharge lamp DL is lit and stops the generation of the high voltage pulse from the start pulse generation circuit 7. . The lighting determination circuit OC includes a current transformer CT whose primary winding is connected in series with the discharge lamp DL, a rectifier DB1 that full-wave rectifies the secondary winding of the current transformer CT, and a capacitor C3 that smoothes the output of the rectifier DB1. A transistor Q3 that is turned on when the voltage across the capacitor C3 is equal to or higher than a predetermined voltage, resistors R4 and R5 that apply a base current to the transistor Q3 according to the voltage across the capacitor C3, and between the collector and emitter of the transistor Q3 And a full-wave rectifier DB2 having a DC side end connected thereto, and a resistor R6 for adjusting the discharging time of the charge of the capacitor C3 is inserted between the connection points of the capacitor C3 and the resistor R5. The time constant by the capacitor C3 and the resistor R6 is appropriately set according to the time for which residual ions disappear after the discharge lamp DL is turned off. The capacitor C3 and the resistor R6 constitute delay means.

As shown in FIG. 17, when the AC power supply AC is turned on at time t3, the discharge lamp DL is in a non-lighting state, and the lamp current I _DL does not flow as shown in FIG. No current flows through the primary winding. Accordingly, no voltage is generated across the capacitor C3 as shown in FIG. 17B, the transistor Q3 is off as shown in FIG. 17C, and the start pulse generation circuit 7 operates. As shown in FIG. 17D, high voltage pulses are repeatedly generated until the discharge lamp DL is turned on. When the discharge lamp DL is lit at time t4, the lamp current I _DL flows as shown in FIG. 17A, and the capacitor C3 is charged as shown in FIG. ), The transistor Q3 is turned on, and the generation of the high voltage pulse from the start pulse generation circuit 7 is stopped as shown in FIG.

  In the lighting state of the discharge lamp DL, as shown in FIG. 17 (a), when the transition to the non-lighting state occurs at time t5 due to extinction or the like, the charge of the capacitor C3 is charged with the capacitor C3 and the resistor R6 as shown in FIG. Discharge according to the time constant determined by. When the terminal voltage of the capacitor C3 decreases until the transistor Q3 can no longer maintain the ON state at the time t6, the transistor Q3 is turned OFF as shown in FIG. 17C, and the start pulse generating circuit 7 as shown in FIG. , A high voltage pulse is generated again to attempt to restart the discharge lamp DL. Here, the time constant determined by the capacitor C3 and the resistor R6 is longer than the time that the residual ions inside the discharge lamp DL disappear after the discharge lamp DL shifts from the lighting state to the non-lighting state. The transistor Q3 is set to be kept on. Therefore, before the discharge lamp DL shifts from the lighting state to the non-lighting state and the residual ions disappear, it is prevented that a high voltage pulse is generated from the start pulse generation circuit 7 and a slight discharge is generated in the discharge lamp DL ( For example, see Patent Document 2).

Japanese Patent No. 2778257 JP-A-5-174985 JP 11-176583 A Japanese Patent Application Laid-Open No. 11-054290 JP-A-10-270182 Japanese Utility Model Publication No. 04-199998 JP-A-10-106767

  In the conventional discharge lamp lighting device (Patent Document 1), the monitoring control unit 105 first drives the high voltage generating means 102 for starting at the time of starting, and monitors the starting state by the output of the current detecting means 104 and fails to start. In this case, the sequence of driving the starting high voltage generating means 102 again and monitoring the starting state by the output of the current detecting means 104 is repeated up to a predetermined number of times, and if the starting fails, the driving of the starting high voltage generating means 102 is repeated. Is stopped and the power supply by the power supply unit 101 is stopped. However, since the high voltage pulse is applied when the inner tube is at a high temperature and a high voltage, the inner tube may not discharge and may cause discharge in the outer tube. .

  In addition, it is not assumed that the high voltage pulse is applied and stopped at a shorter interval than the normal start so as not to continue the application of the high voltage pulse even if the outer tube discharge occurs.

  In the conventional discharge lamp lighting device (Patent Document 2), ions remain between the electrodes of the discharge lamp DL immediately after the discharge lamp DL disappears, and a high voltage pulse is applied before disappearance of the residual ions. When the contact state of the connection terminal is insufficient, a slight discharge is started without reaching the lighting state, and this fine discharge continues and current continues to flow to the connection terminal, increasing the electrical stress on the connection terminal and causing ignition.・ Smoke may occur, so when the discharge lamp DL shifts from the lighting state to the non-lighting state, after the residual ions disappear, a high voltage pulse is generated from the starting pulse generation circuit 7 and restarted. Prevents the occurrence of slight discharge. However, since the residual ions disappear after a time of about several tens of msec after the extinction, when the high voltage pulse is generated and restarted after the residual ions disappear, the temperature of the arc tube (inner tube) is reached for several tens of msec. Is still high, and there is a risk that the inner tube will not discharge and cause discharge in the outer tube.

  In addition, it is not assumed that the high voltage pulse is applied and stopped at a shorter interval than the normal start so as not to continue the application of the high voltage pulse even if the outer tube discharge occurs.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a safe high-pressure discharge lamp lighting device that appropriately avoids outer-tube discharge of a high-pressure discharge lamp.

  A high pressure discharge lamp lighting device according to the present invention includes a high pressure discharge lamp having an arc tube and an outer tube that holds and protects the arc tube, a power supply unit that supplies electric power to the high pressure discharge lamp, and a high pressure discharge lamp. A high pressure discharge lamp lighting device having a start pulse generating circuit for supplying a high voltage for power supply and a control circuit for controlling the power supply unit and the start pulse generating circuit has temperature characteristics correlated with the temperature rise and fall characteristics of the arc tube A thermal switch that is thermally coupled to a circuit component of the power supply unit and energizes or shuts off at a predetermined temperature or more, and a signal synthesis unit that prevents the start pulse generation circuit from being driven when the thermal switch is energized or interrupted. It is provided.

  A high pressure discharge lamp lighting device according to the present invention includes a thermal switch that is thermally coupled to a circuit component of a power feeding unit having a temperature characteristic correlated with a temperature rise and fall characteristic of an arc tube, and that is energized or cut off at a predetermined temperature or more. In addition, when the thermal switch is energized or cut off, the signal synthesizing means is provided so as not to drive the starting pulse generating circuit. Therefore, when a high voltage pulse is applied to the lamp in a state where the lamp temperature is high after the lamp is turned off. The risk of abnormal discharge occurring in the outer tube without discharging in the inner tube can be avoided.

It is a figure which shows Embodiment 1, and is a block diagram which shows the structure of a high pressure discharge lamp lighting device. It is a figure which shows Embodiment 1, and is a block diagram which shows an example of a high pressure discharge lamp. It is a figure which shows Embodiment 1 and is a flowchart of control. It is a figure which shows Embodiment 1, and is a figure which shows the pulse waveform applied at the time of normal starting control. It is a figure which shows Embodiment 1, and is a figure which shows the pulse waveform applied at the time of starting control at the time of restart. It is a figure which shows Embodiment 1, and is a figure which shows the change of the dischargeable voltage of the inner tube | pipe after light extinction. It is a figure which shows Embodiment 1, and is a figure which shows the change of the temperature of the outer tube | pipe center part after light extinction of the high pressure discharge lamp (use of a sealing | equivalent apparatus) after light extinction. It is a figure which shows Embodiment 1, and is a figure which shows the temperature characteristic of the arc tube highest temperature part and outer tube | pipe center part of a high pressure discharge lamp (100W, bare lighting). It is a figure which shows Embodiment 1, and is a figure which shows the discontinuous arc discharge when not lighting normally in the starting control at the time of restart. It is a figure which shows Embodiment 2, and is a block diagram which shows the structure of a high pressure discharge lamp lighting device. It is a figure which shows Embodiment 2, and is a figure which shows the change of the lamp | ramp temperature at the time of lamp lighting and light extinction, and the heat generating part temperature of a lighting device. It is a figure which shows Embodiment 3, and is a block diagram which shows the structure of a high pressure discharge lamp lighting device. It is a flowchart figure of control of the conventional high pressure discharge lamp lighting device. It is a block diagram which shows the structure of the conventional high pressure discharge lamp lighting device. It is a circuit diagram of the discharge lamp lighting device provided with the starting pulse generation circuit 7 which superimposes a high voltage pulse on the conventional power supply voltage, and starts a discharge lamp. It is operation | movement explanatory drawing of the conventional discharge lamp lighting device. It is operation | movement explanatory drawing of the conventional discharge lamp lighting device.

Embodiment 1 FIG.
1 to 9 are diagrams showing Embodiment 1, FIG. 1 is a block diagram showing a configuration of a high pressure discharge lamp lighting device, FIG. 2 is a configuration diagram showing an example of a high pressure discharge lamp, and FIG. 3 is a flowchart of control. 4 is a diagram showing a pulse waveform applied during normal start control, FIG. 5 is a diagram showing a pulse waveform applied during start control during restart, and FIG. 6 is a diagram showing a change in dischargeable voltage of the inner tube after extinguishing. FIG. 7 is a diagram showing a change in the temperature of the central portion of the outer tube after extinguishing the high-pressure discharge lamp (using a sealed device) after extinguishing, and FIG. 8 is the maximum temperature portion of the arc tube of the high-pressure discharge lamp (100 W, bare lighting) FIG. 9 is a diagram showing discontinuous arc discharge in the case where the lighting is not normally performed in the start control at the time of restart.

As shown in FIG. 1, in the high pressure discharge lamp lighting device, when the AC power supply 1 is turned on, the control power supply circuit 10 generates the control power supply, the control circuit 9 (microcomputer) operates, Control signals are sent to the step-down inverter 4, the rectangular wave circuit 6, and the start pulse generation circuit 7, and each starts operation. The step-up inverter 3 boosts the output rectified by the rectifier circuit 2 to a specified voltage, and the step-down inverter 4 adjusts the output so that the current flowing through the high-pressure discharge lamp 8 becomes a specified current. The rectangular wave circuit 6 outputs an AC rectangular wave voltage having a specified frequency to the high pressure discharge lamp 8. The start pulse generation circuit 7 generates a high pressure pulse to start the high pressure discharge lamp 8. Further, the current of the high-pressure discharge lamp 8 is detected by the current detection resistor 5 to determine lighting.
A power supply unit that supplies power to the high-pressure discharge lamp 8 includes an AC power source 1, a rectifier circuit 2, a step-up inverter 3, a step-down inverter 4, and a rectangular wave circuit 6.

  FIG. 2 is a diagram showing a configuration of a metal halide as an example of a high pressure discharge lamp. As shown in the drawing, the high-pressure discharge lamp 8 uses ceramic or quartz glass for the arc tube 11 (inner tube), and a pair of electrodes are sealed inside. In addition, after the inside of the arc tube 11 is evacuated, a light emitting metal substance (additive) such as mercury, sodium, and metal halide is enclosed together with a starting gas such as argon gas or xenon gas.

For example, hard glass is used for the outer tube 12 (quartz glass is also used), and the inside is filled with an inert gas such as nitrogen gas after high vacuum or high vacuum. The role of the outer tube 12 is as follows.
(1) Holding (protecting) the arc tube 11
(2) Insulation of arc tube 11 (3) Antioxidation of lead wires 13a, 9b, etc. (4) Cut of ultraviolet rays

  The E26 base 14 holds the high-pressure discharge lamp 8 in the fixture and makes electrical connection with the lighting device. The metal halide in FIG. 2 is a one-piece base. A lead wire 13a connected to one electrode of the arc tube 11 and a lead wire 13b connected to the other electrode of the arc tube 11 are provided from the E26 base 14 to the inside of the outer tube 12. A getter 15 for absorbing the impure gas is attached.

  This embodiment is characterized by the control of the start pulse generation circuit 7 of the control circuit 9 (microcomputer), and performs the start control at the restart when the high pressure discharge lamp 8 goes out by the method described below. It is. Hereinafter, the start control method at the time of restart when the high pressure discharge lamp 8 is extinguished will be described with reference to the flowchart of FIG.

  In step S1, a lighting switch (not shown) is turned on to turn on the power. In the starting control by the starting pulse generating circuit 7, the starting pulse generating circuit 7 generates a pulsed high voltage that is driven for 30 seconds and stopped for 30 seconds as shown in FIG. Step S2). Next, in step S3, the lighting time counter that counts the lighting time of the high-pressure discharge lamp 8 is reset. In step S4, the high pressure discharge lamp 8 is turned on and controlled by the AC power from the step-down inverter 4, and the lighting time of the high pressure discharge lamp 8 is counted up by the lighting time counter (step S5).

  The turning-off of the high-pressure discharge lamp 8 being lit is monitored (step S6), and if the high-pressure discharge lamp 8 has turned off, it is determined whether the lighting time counter of the high-pressure discharge lamp 8 has exceeded 10 minutes (step S7). If the lighting time counter does not exceed 10 minutes, the process returns to the start control in step S2.

  This is because when the lighting time counter does not exceed 10 minutes, that is, when the lamp temperature is still low at the beginning of lighting, the inner tube can be restarted even if a high voltage pulse is applied and restarted immediately after the high pressure discharge lamp 8 is extinguished. This is because there is no risk of discharge occurring in the outer tube.

  When the lighting time counter of the high-pressure discharge lamp 8 exceeds 10 minutes, the count is reset (step S8), and the time when the arc tube is statistically easy to restart while counting up by 1 (a low value of 150W or less). In the high-pressure electric discharge lamp, lighting is stopped (for example, about 5 minutes) (step S6).

Hereinafter, the reason and effect of stopping the lighting for about 5 minutes after the high-pressure discharge lamp 8 has disappeared will be described.
FIG. 6 is a diagram showing a change in dischargeable voltage of the inner tube after extinguishing. When the high-pressure discharge lamp 8 is extinguished from a state where it is stably lit, the arc tube 11 of the high-pressure discharge lamp 8 is very hot immediately after extinguishing. Therefore, the dischargeable voltage of the inner tube rapidly increases in a short time from the voltage at the time of stable lighting, and then the arc tube temperature of the high-pressure discharge lamp 8 decreases with time, and the inner tube discharges. The possible voltage is also reduced. In 5 minutes after the light is turned off, the dischargeable voltage of the inner tube is about 4 kv.

  The dischargeable voltage of the inner tube of the high-pressure discharge lamp 8 after extinguishing is related to the arc tube temperature. FIG. 7 shows the central portion of the outer tube after the extinguishing of the high-pressure discharge lamp (100 W, using a sealed equivalent device) after extinguishing. It is a figure which shows an example of the change of temperature, and the change of the surface temperature of the outer tube | pipe center part when a 100W lamp is lighted for 1 hour continuously, and is extinguished is measured. The outer tube surface temperature when the lamp was lit continuously for 1 hour was 338 ° C., and the outer tube surface temperature when cooled (stopped) for 5 minutes was 193 ° C., and cooling for 5 minutes lowered the temperature by about 57%.

  FIG. 8 is a diagram showing an example of the temperature characteristics of the arc tube maximum temperature part and the outer tube center part of a high pressure discharge lamp (100 W, barely lit). The cooling characteristic after 15 minutes of aging is measured at an ambient temperature of 26 ° C. It is a thing. 10 minutes after lighting, both the arc tube 11 and the outer tube 12 are close to the stable temperature. 15 minutes after lighting, the arc tube surface temperature is 900 ° C. or more, and the outer tube center surface temperature is 200 ° C. or more. When restarting 5 minutes after the light is turned off, the arc tube surface temperature is 280 ° C., and the outer tube center surface temperature is 100 ° C.

  By the way, the high pressure discharge lamp 8 has the structure shown in FIG. 2, and is applied to the high pressure discharge lamp 8 due to the restriction of the insulation distance between the lead wire 13a and the lead wire 13b in the outer tube and the creeping distance between the different poles of the E26 base 14. The high voltage to be applied needs to be 5 kv or less.

  The minimum voltage at which the arc tube 11 can be started is 3 kv.

  Therefore, any time from when the discharge voltage of the inner tube falls below 5 kv after the high-pressure discharge lamp 8 is extinguished, if a high-pressure pulse of 3 to 5 kv is applied to the high-pressure discharge lamp 8, a discharge occurs in the outer tube. The arc tube 11 is discharged and can be normally lit.

  However, as a product, we want to make the suspension period after turning off as short as possible. Therefore, it is desirable to restart immediately when the dischargeable voltage of the inner tube falls below 5 kv. From FIG. 6, it can be said that the stop period is suitably about 5 minutes when the dischargeable voltage of the inner tube is about 4 kv.

  For example, by stopping the lighting for about 5 minutes after the high-pressure discharge lamp 8 is extinguished, the discharge in the outer tube can be suppressed without deteriorating the value of the product, and the arc tube 11 can be discharged and normally lit. .

  Returning to FIG. 3, in the start control at restart by the start pulse generation circuit 7 in step S10, as shown in FIG. 5, the start pulse generation circuit 7 is not maintained even if an outer tube discharge occurs, as shown in FIG. A pulsed high voltage of, for example, 10 seconds driving and 10 seconds stopping is generated at a shorter interval, and the dielectric breakdown of the sealed gas of the high pressure discharge lamp 8 is performed. Then, after the pulse application for 60 seconds, for example, a rest period of 60 seconds is provided. Thereby, it is possible to suppress the heating by the glow discharge of the arc tube 11 and start it smoothly.

  In step S10, it is determined whether the high-pressure discharge lamp 8 is turned on. If the high-pressure discharge lamp 8 is normally turned on, the process returns to step S4. If it is not normally lit, it is determined in step S12 whether the number of discontinuous arc discharges (see FIG. 9) has exceeded, for example, 1024. If not, the process returns to step S10. It is determined whether or not the count number k is 3. Since the count number is now 1, the process returns to step S9.

  In step S9, the count is incremented by 1 and the restart start control is performed again (step S10). Lighting determination is performed (step S11), and when the lighting is normal, the process returns to step S4. If it is not normally lit, it is determined in step S12 whether the number of discontinuous arc discharges has exceeded, for example, 1024. If not, the process returns to step S10, and if it has exceeded, the count number k is 3 in step S13. Since the count number is now 2, the process returns to step S9 again.

  In step S9, the count is incremented by 1 and the restart start control is performed again (step S10). Lighting determination is performed (step S11), and when the lighting is normal, the process returns to step S4. If it is not normally lit, it is determined in step S12 whether the number of discontinuous arc discharges has exceeded, for example, 1024. If not, the process returns to step S10, and if it has exceeded, the count number k is 3 in step S13. Since the count number is now 3, the lighting device is stopped in step S14.

  As described above, when the high-pressure discharge lamp 8 goes off at the beginning of lighting, the lamp temperature is low and the inner tube can be discharged. be able to.

  In addition, when the high pressure discharge lamp 8 is turned on after the lamp temperature is stabilized and then extinguishes, immediately after applying a high voltage pulse and restarting, there is a risk of causing discharge in the outer tube without discharging in the inner tube. Abnormal discharge in the outer tube can be avoided by stopping for about 5 minutes after it has disappeared.

  In addition, by applying and stopping the application of the high voltage pulse at the time of restart at intervals shorter than those at the time of normal starting, it is possible to prevent the high voltage pulse from being sustained even if an outer tube discharge occurs.

  Moreover, when discontinuous arc discharge is detected, it does not stop immediately, but, for example, a restart mode is tried three times, and abnormality determination can be ensured and malfunction can be prevented.

Embodiment 2. FIG.
10 and 11 are diagrams showing the second embodiment, FIG. 10 is a block diagram showing the configuration of the high-pressure discharge lamp lighting device, and FIG. 11 is the change in the lamp temperature when the lamp is lit and when the lamp is turned off, and the heat generating part temperature of the lighting device. FIG.
In the first embodiment, the lighting time of the high-pressure discharge lamp 8 is counted by the microcomputer with the lighting time counter. When the lighting time is shorter than the predetermined time, the normal start control is performed immediately after turning off, and the lighting time is predetermined. When it is longer than the time, the start pulse generation circuit 7 starts pulse application after a predetermined stop period, and this pulse application shows an example of controlling to apply and stop at a shorter interval than the normal start time, In this embodiment, the circuit component temperature of the lighting device having a temperature characteristic correlated with the temperature rise / decrease characteristic of the lamp is detected, and when the circuit component temperature exceeds a certain temperature, the start pulse generation circuit is not driven. Then, the lamp is extinguished and the circuit component temperature decreases, and when the temperature falls below a certain temperature after a predetermined time, the starting pulse generating circuit is driven.

  There is a correlation between the lamp temperature and the temperature of the transistor Q5, which is a component in the step-up inverter 3 of the lighting device, for example, and the respective temperatures during and after the lamp change change as shown in FIG. Thus, the change in the lamp temperature and the temperature of the transistor Q5 are approximate.

  The configuration of the high pressure discharge lamp lighting device will be described with reference to FIG. A thermal switch S1 is provided that is thermally coupled to the transistor Q5, which is one circuit component of the boost inverter 3. The term “coupled in terms of temperature” means that the heat of the transistor Q5 is coupled so as to be efficiently transmitted to the thermal switch S1. The thermal switch S1 is set so as to be energized at a temperature equal to or higher than the temperature Th (dotted line in FIG. 11) of the transistor Q5 corresponding to a lamp temperature of 200 ° C., for example. Then, signal synthesizing means 16 is provided so as not to drive the start pulse generating circuit 7 when the thermal switch S1 is energized.

  If the temperature of the transistor Q5 is equal to or higher than Th, the thermal switch S1 is turned on, the control signal from the control circuit 9 to the start pulse generating circuit 7 is short-circuited to GND, and the start pulse generating circuit 7 does not operate. When the lamp is turned off and the temperature is lowered, the temperature of the transistor Q5 is also lowered. When the temperature of the transistor Q5 becomes equal to or lower than Th after a predetermined time, the thermal switch S1 is turned off, and a signal from the control circuit 9 is sent to the start pulse generating circuit 7. Then, the start pulse generating circuit 7 is driven.

  The thermal switch S1 is set to be energized at the temperature Th of the transistor Q5 or higher, but conversely, may be set to be shut off at the temperature Th of the transistor Q5 or higher. In this case, the signal synthesizing means 16 operates so as not to drive the start pulse generating circuit 7 when the thermal switch S1 is cut off.

  According to the present embodiment, the thermal switch S1 is provided that is thermally coupled to the transistor Q5, which is one circuit component of the booster inverter 3, and the thermal switch S1 has a lamp temperature of, for example, 200 ° C. It is set to energize at a temperature Th (dotted line in FIG. 11) or higher, and is provided with signal synthesizing means 16 so as not to drive the start pulse generating circuit 7 when the thermal switch S1 is energized. When a high voltage pulse is applied to the lamp in a high state, it is possible to avoid the risk of abnormal discharge occurring in the outer tube without discharging in the inner tube.

Embodiment 3 FIG.
FIG. 12 is a block diagram showing the configuration of the high pressure discharge lamp lighting device according to the third embodiment.
In the figure, the current detection signal from the current detection resistor 5 is discriminated by a comparator 17 (lighting discriminating means) and is set to a signal that becomes 1 level when it is lit, and the change in this signal is used (coupling in series with the comparator 17). The lighting timer circuit 18 (for example, a circuit using a 555 series timer IC) is reset by changing the signal by connecting the capacitor 20.

  The output of the lighting timer circuit 18 is set to L level until the counter after reset reaches, for example, 10 minutes (first predetermined time), and a CR delay circuit (another delay circuit may be used) that is a restart delay circuit using this signal. The capacitor Ct is discharged so that no electric charge is accumulated. The restart delay circuit 19 charges the capacitor Ct with a signal that becomes 1 when the light is turned on, discharges the capacitor Ct → the resistor Rt when the light is turned off, and the time constant allows Qt to be maintained in the saturation region. Hold at potential. The restart delay circuit 19 holds and blocks the start pulse generation circuit drive signal output from the control circuit 9 at the GND potential at the time constant time (second predetermined time) of the capacitor Ct and the resistor Rt. The diode D prevents the charge of the capacitor Ct from flowing backward to the comparator 17 side when the light is turned off, and the charging resistor R1 is connected to the diode D in series.

  According to the present embodiment, when the lighting time of the lamp exceeds 10 minutes (first predetermined time), the start pulse generating circuit 7 is time constant time (second predetermined time) of the capacitor Ct and the resistor Rt when the lamp is turned off. Since the operation is stopped, the start pulse is not applied to the lamp when the lamp is in a high temperature and high pressure state, so that the risk of abnormal discharge occurring in the outer tube without discharging in the inner tube can be avoided.

  Further, when the lamp lighting time is within 10 minutes, the restart delay circuit does not operate because the capacitor Ct has no electric charge, and a start pulse is generated immediately, thereby eliminating an unnecessary stop period when the lamp temperature is low. be able to.

  1 AC power supply, 2 rectifier circuit, 3 step-up inverter, 4 step-down inverter, 5 current detection resistor, 6 rectangular wave circuit, 7 start pulse generation circuit, 8 high pressure discharge lamp, 9 control circuit, 10 control power supply circuit, 11 arc tube, 12 outer tube, 13a, 13b lead wire, 14 E26 base, 15 getter, 16 signal synthesis means, 17 comparator, 18 lighting timer circuit, 19 restart delay circuit.

Claims (2)

A high-pressure discharge lamp having an arc tube and an outer tube that holds and protects the arc tube, and a boost inverter that supplies power to the high-pressure discharge lamp and boosts the output rectified by the rectifier circuit to a specified voltage. In a high pressure discharge lamp lighting device comprising: a power supply unit; a start pulse generating circuit that supplies a high voltage for starting to the high pressure discharge lamp; and a control circuit that controls the power supply unit and the start pulse generating circuit.
A thermal switch that is coupled in temperature with a transistor of the step-up inverter having a temperature characteristic correlated with a temperature rise and fall characteristic of the arc tube, and that is energized or cut off at a predetermined temperature or higher;
Signal synthesizing means for preventing the start pulse generating circuit from being driven when the thermal switch is energized or interrupted;
A high pressure discharge lamp lighting device comprising: The high-pressure discharge lamp lighting device according to claim 1, wherein the predetermined temperature is about 200 ° C.

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