JPH01298687A - Ignitor for high-voltage electric-discharge lamp - Google Patents

Abstract

PURPOSE:To enable the start and restart of a high-voltage electric-discharge lamp without affording an excessive stress to the lamp by forming the electrode of a two-terminal discharge gap for supplying a high-voltage pulse voltage to the high-voltage electric-discharge lamp of a particular conductive material. CONSTITUTION:A discharge current is run into a two-terminal discharge gap 7 according to the charging voltage of a charging circuit 6, and a high-voltage pulse is applied to a high-voltage electric-discharge lamp 3 through a booster transformer 8. At least one of the electrodes 7a, 7b of the gap 7 is formed of a thermosensible displacement type conductive material in which the length between gaps is gradually increased according to the self-exothermic in the discharge, and the lamp 3 starts at the state having a small crest value in the initial start easy to start, and the lamp 3 restarts at the state having a high crest value in the restart difficult to start. thus, the start and the instantaneous restart after putting out can be conducted without giving an excessive stress to the lamp and shortening its life because of the crest value proper to the state.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an igniter for a high-pressure discharge lamp that applies a high-voltage pulse for starting to a high-pressure discharge lamp to light the high-pressure discharge lamp. The present invention relates to an igniter for a high-pressure discharge lamp that can instantaneously restart a high-pressure discharge lamp.

[Conventional technology]

A conventional high-pressure discharge lamp igniter that applies a high-voltage pulse for starting a high-pressure discharge lamp connected to a power supply via an inductive ballast is supplied with a high-voltage generation circuit and the output of this high-voltage generation circuit. A charging circuit, a two-terminal discharge gap to which the output voltage of this charging circuit is applied, and a two-terminal discharge gap from the charging circuit.
A step-up transformer has a primary winding inserted in series in the current-carrying path to the terminal discharge gear 7 pin, and a secondary winding inserted in series in the current-carrying path from the power supply to the high-pressure discharge lamp, and the secondary winding of the step-up transformer. It consists of a bypass capacitor that applies the induced voltage in the winding across the high-pressure discharge lamp by bypassing the inductive ballast (as disclosed in Japanese Patent Application No. 62-326328 as a conventional example).

In this igniter for high-pressure discharge lamps, when the output voltage of the charging circuit, which is charged by the output current of the high-voltage generating circuit, exceeds the discharge starting voltage of the two-terminal discharge gap, the charge of the charging circuit is transferred to the primary winding of the step-up transformer. is rapidly discharged through the transformer, inducing a high voltage pulse in the secondary winding of the step-up transformer. This high-voltage pulse is then applied to the high-pressure discharge lamp through the bypass capacitor, and as a result, the high-pressure discharge lamp starts and lights up.

In this case, the voltage required to start the high-pressure discharge lamp is several kilovolts at the time of initial starting, but several tens of kilovolts are required when it is desired to restart the lamp instantly immediately after the lamp has been turned off.

Therefore, in the above-mentioned igniter for a high-pressure discharge lamp, which is intended to instantly restart the high-pressure discharge lamp immediately after extinguishing, the circuit is designed to generate, for example, several tens of KVO high-voltage pulses.

[Problem to be solved by the invention]

As mentioned above, when a high-pressure discharge lamp igniter whose circuit is designed to generate, for example, several tens of KVO high-voltage pulses is used to start a high-pressure discharge lamp, the peak value of the high-voltage pulse applied to the high-pressure discharge lamp during initial startup becomes excessive,
There is a problem in that excessive stress is applied to the high-pressure discharge lamp, and the life of the high-pressure discharge lamp is extremely shortened.

An object of the present invention is to provide an igniter for a high-pressure discharge lamp that can instantly restart a high-pressure discharge lamp immediately after extinguishing without shortening the life of the high-pressure discharge lamp.

[Means to solve the problem]

The igniter for a high pressure discharge lamp of the present invention applies a high voltage pulse for starting to a high pressure discharge lamp connected to a power source via an inductive ballast.

The igniter for a high-pressure discharge lamp includes a DC high voltage generation circuit, a charging circuit that is charged with the output current of the DC high voltage generation circuit, and a two-terminal discharge gap to which the charging voltage of the charging circuit is applied. A step-up transformer has a primary winding inserted in series in the current-carrying path from the charging circuit to the two-terminal discharge gap, and a secondary winding inserted in series in the current-carrying path from the power supply to the high-pressure discharge lamp; It is equipped with a bypass capacitor that applies the induced voltage of the next winding across the high-pressure discharge lamp by bypassing the inductive ballast, and connects at least one electrode of the two-terminal discharge gap to the other electrode as self-heating occurs due to discharge. It is made of a temperature-sensitive displacement conductive material that gradually increases the gap length between the two.

Further, the two-terminal discharge gap described above may be placed near the high-pressure discharge lamp to receive heat from the high-pressure discharge lamp.

[For production]

In the configuration of the present invention, the charging circuit is charged with the output current of the DC high voltage generation circuit, and when the charging voltage of the charging circuit exceeds the discharge start voltage of the two-terminal discharge gap, the charged charge of the charging circuit is transferred to the primary of the step-up transformer. It is rapidly discharged through the winding, and thereafter the charging and discharging operations of the charging circuit are repeated.

Each time the charge in the charging circuit is discharged, a high voltage pulse is generated in the secondary winding of the step-up transformer, and this high voltage pulse is applied to the high-pressure discharge lamp through the bypass capacitor, and the high-pressure discharge lamp is started. The lights come on.

At this time, the two-terminal discharge gap consists of at least one electrode made of a temperature-sensitive displacement conductive material that gradually increases the gap length between it and the other electrode as it generates self-heating due to discharge. When discharge begins, the temperature of at least one of the electrodes increases over time due to self-heating caused by the discharge, and the gap length between the two electrodes and the other electrode gradually increases. As a result, the discharge starting voltage of the two-terminal discharge gap increases as time passes after the power is turned on, and a wave of high voltage pulses is generated in the secondary S line of the step-up transformer as the two-terminal discharge gap discharges. The high value will gradually increase.

Therefore, at the time of initial starting, when the lamp is easy to start, the high-pressure discharge lamp starts and lights up when the peak value of the high-voltage pulse is low immediately after the power is turned on. On the other hand, when restarting the lamp, which is difficult to start, the high-pressure discharge lamp starts and lights up when the peak value of the high voltage pulse increases to a point where starting is possible after a period of time has passed after the power is turned on. Note that the period during which the peak value of the high-voltage pulse changes is extremely short compared to the period from when the high-pressure discharge lamp is turned off until the high-pressure discharge lamp cools down.

This igniter for high-pressure discharge lamps can start and light the high-pressure discharge lamp in a state where the peak value of the high-voltage pulse is small at the time of initial start-up, reducing stress on the electrodes of the high-pressure discharge lamp at the time of initial start-up. This will not shorten the life of the high-pressure discharge lamp. Moreover, when restarting, the peak value of the high-voltage pulse can be increased, and the high-pressure discharge lamp can be instantly restarted immediately after extinguishing. Also, during this restart, a high voltage pulse with an unnecessarily large peak value is not applied.
Therefore, no excessive stress is applied to the high-pressure discharge lamp at this time either, and the life of the high-pressure discharge lamp is not shortened in this respect as well.

Furthermore, if the two-terminal discharge gap is placed near the high-pressure discharge lamp to receive the heat generated by the high-pressure discharge lamp, at the time of initial startup, the high-pressure discharge lamp is cold and the gap length of the two-terminal discharge gap is small. The discharge starting voltage is low, and therefore the peak value of the high voltage pulse generated in the secondary winding of the step-up transformer due to discharge in the two-terminal discharge gap is small. On the other hand, at the time of restart, the high-pressure discharge lamp was generating heat due to lighting, so the gap length of the two-terminal discharge gap became large, and the discharge starting voltage became high. Therefore, the peak value of the high voltage pulse generated in the secondary winding of the step-up transformer due to discharge in the two-terminal discharge gap is large.

Therefore, at the time of initial starting, where starting is easy, the high-pressure discharge lamp starts and lights up in a state where the peak value of the high-voltage pulse is small. On the other hand, when restarting, which is difficult to start, the high-pressure discharge lamp starts and lights up in a state where the peak value of the high-voltage pulse is large.

In this igniter for high-pressure discharge lamps, when restarting the high-pressure discharge lamp, the peak value of the high-voltage pulse is large from the beginning, and the high-pressure discharge lamp can be restarted instantly.

〔Example〕

A first embodiment of the present invention will be described based on FIGS. 1 to 4. That is, as shown in FIG. 1, this igniter for a high-pressure discharge lamp is powered by, for example, a commercial AC power source (DC power source, high frequency power source, etc.).

A high-voltage pulse for starting is applied to a high-pressure discharge lamp 3 connected to a rectangular wave power source 1 via an inductive ballast 2.

This igniter for a high-pressure discharge lamp includes a DC high voltage generation circuit 5 that is supplied with power from both ends of the bypass capacitor 4 between terminals a and b, a terminal c of this DC high voltage generation circuit 5,
A charging circuit 6 consisting of a capacitor 6a and a resistor 6b that are charged with an output current from between d, a two-terminal discharge gap 7 to which the charging voltage of this charging circuit 6 is applied, and a two-terminal discharge gap 7 from the charging circuit 6 to the two-terminal discharge gap 7. A step-up transformer 8 has a primary winding n1 inserted in series in the energization path of Next, the induced voltage of the S line n2 is bypassed by the inductive ballast 2 and the high pressure discharge lamp 3
a bypass capacitor 4 to be applied between both ends of the
For example, one electrode 7a of the two-terminal discharge gap 7 is made of a temperature-sensitive displacement conductive material whose gap length between it and the other electrode 7b gradually increases as self-heating occurs due to discharge.

Specifically, as shown in FIG. 3, the two-terminal discharge gap 7 has a structure in which a pair of rectangular electrodes 7a and 7b are erected facing each other on a base 7c made of an insulating material. is made of bimetal or shape memory alloy. Note that the electrode 7b may also be made of a similar temperature-sensitive displacement conductive material.

In this igniter for a high-pressure discharge lamp, before the high-pressure discharge lamp 3 is turned on, both voltages of the bypass capacitor 4 are almost the power supply voltage, and this voltage is the same as that of the high-voltage generating circuit 5.
is applied between terminals a and b, and between terminals c and d in Fig. 2 (a
As shown at t, a DC high voltage VCa+ (>discharge starting voltage VC) is generated.

Then, the capacitor 6a of the charging circuit 6 is charged by the output current of the DC high voltage generating circuit 5 through the resistor 6b, and the voltage Vc across the capacitor 6a of the charging circuit 6 gradually increases as shown in FIG. The above capacitor 6
The voltage VC across a is the discharge starting voltage of the two-terminal discharge gap 7. , the two-terminal discharge gap 7 is discharged, and the charge in the capacitor 6a is transferred to the primary winding n of the step-up transformer 8.
is rapidly discharged through the secondary winding n2 of the step-up transformer 8, and a high voltage pulse (2) as shown in FIG.
is applied to Thereafter, the above operation is repeated, and the high pressure discharge lamp 3 is started and lit at an appropriate time.

When the high pressure discharge lamp 3 lights up, the DC high voltage generation circuit 5
The voltage applied between terminals a and b of the high pressure discharge lamp 3 is
Since the lamp voltage is almost equal to the lamp voltage and is considerably lower than the power supply voltage, the DC high voltage generated between terminals c and d of the DC high voltage generating circuit 5 becomes Vct as shown in FIG. 2(a).
t (<discharge starting voltage VC), and the DC high voltage Vc
Even if the capacitor 6a of the charging circuit 6 is charged by 4z, the voltage across the capacitor 6a is ■. does not exceed the discharge starting voltage v6. Therefore, the discharge in the two-terminal discharge gap 7 is stopped, and the generation of the high voltage pulse V is stopped.

At this time, the two-terminal discharge gap 7 is made of a temperature-sensitive displacement conductive material in which the gap length between the one electrode 7a and the other electrode 7b gradually increases as self-heating occurs due to discharge. When the power is turned on and discharge begins, the temperature of one electrode 7a rises over time due to self-heating due to discharge, and the gap length between it and the other electrode 1i7b gradually increases. That is, the electrode 7a is bent due to self-heating, and as shown by the arrow X in FIG. 3, the state gradually changes from the state shown by the solid line to the state shown by the broken line, and the gap length increases. As a result, as shown in +a+ in FIG. 4, the discharge start voltage V6 of the two-terminal discharge gap 7 increases as time passes after the power is turned on, and therefore the voltage across the capacitor 6a of the charging circuit 6 increases. As the peak value of V gradually increases, the energy stored in the capacitor 6a increases, and the peak value of the high voltage pulse V, generated in the secondary winding nnt of the step-up transformer 8 due to the discharge of the two-terminal discharge gap 7 increases. It will gradually increase as shown in Figure 4 (bl).

Therefore, at the time of initial starting, which is easy to start, the high-pressure discharge lamp 3 starts and lights up when the peak value of the high voltage pulse is low immediately after the power is turned on. On the other hand, when restarting is difficult,
When time passes after the power is turned on and the peak value of the high voltage pulse becomes large enough to start, the high pressure discharge lamp 3 starts and lights up. Note that the period during which the peak value of the high-voltage pulse changes is extremely short compared to the period from when the high-pressure discharge lamp 3 is turned off until the high-pressure discharge lamp 3 cools down.

In this igniter for high-pressure discharge lamps, the high-pressure discharge lamp 3 can be started and lit in a state where the peak value of the high-voltage pulse is small at the time of initial start-up, reducing the stress applied to the electrodes of the high-pressure discharge lamp 3 at the time of initial start-up. can be carried out without shortening the life of the high pressure discharge lamp 3.
Moreover, when restarting, the peak value of the high voltage pulse is increased (
Therefore, the high-pressure discharge lamp 3 can be instantly restarted immediately after being turned off. Also, at this time of restarting, a high voltage pulse with an unnecessarily large peak value is not applied, and excessive stress is not applied to the high pressure discharge lamp 3 at this time as well. The life of lamp 3 will not be shortened.

In this embodiment, the peak value of the high voltage pulse P is made thicker (and the interval between occurrences of the high voltage pulse V becomes longer). It is also possible to control the generation interval of the high voltage pulse VP by decreasing it over time.

A second embodiment of the invention will be described based on FIG.

This igniter for high-pressure discharge lamp, as shown in Figure 5,
1, a resistor 9.10 is added to divide the voltage Ve across the capacitor 6a of the charging circuit 6, and a voltage detection circuit 11 is added to detect when the obtained divided voltage exceeds a predetermined value. The DC high voltage generating circuit 5 is configured to stop generating the DC high voltage in response to the output of the voltage detection circuit 11.

With this configuration, when the high-pressure discharge lamp 3 does not light up due to its lifespan or when there is no load, the rise in the voltage across the capacitor (2) is limited, and therefore the rise in the peak value of the high-voltage pulse (V) is also suppressed to a certain value. Therefore, safety can be ensured when the high-pressure discharge lamp 3 is not lit or under no load.

The rest is the same as the first embodiment.

In addition, in the two-terminal discharge gap 7 shown in FIG. 3, when the distance between the tip gap portions of the pair of electrodes 7a and 7b, that is, the gap length exceeds a certain value, a gap occurs between the pair of electrodes 7a and 7b at the base 7C. Since a discharge occurs and no discharge occurs at the tip gap, if the distance l between the pair of electrodes 7a and 7b at the base 7c is appropriately set, the distance between the pair of electrodes t
Scratch 7a.

No matter how wide the distance between the tip gap parts of 7b becomes,
Discharge starting voltage■. is determined by the interval l. Therefore, even when the high-pressure discharge lamp 3 is not lit or under no load, the high voltage pulse vP does not become abnormally high, and as mentioned above, safety is maintained when the high-pressure discharge lamp 3 is not lit or under no load. can be secured.

A third embodiment of this invention will be described. This igniter for a high pressure discharge lamp has the two-terminal discharge gap 7 shown in FIGS. 1 and 3 placed near the high pressure discharge lamp 3 to receive heat from the high pressure discharge lamp 3, and The configuration is similar to that shown in FIGS. 1 and 3.

With this configuration, not only one electrode 7a of the two-terminal discharge gap 7 is bent due to self-heating due to discharge, but also one electrode 7a of the two-terminal discharge gap 7 is bent due to temperature rise due to heat generation of the high-pressure discharge lamp 30. It will take a turn.

In the case of this embodiment, the two-terminal discharge fixture 7 is arranged near the high-pressure discharge lamp 3 to receive the heat generated by the high-pressure discharge lamp 3, so that the high-pressure discharge lamp 3 is cool at the time of initial startup. The gap length of the two-terminal discharge gap 7 is small, and the discharge starting voltage V6 is low. Therefore, as the two-terminal discharge gap 7 discharges, the secondary winding n of the step-up transformer 8.

The peak value of the high voltage pulse generated is small. On the other hand, at the time of restart, the high-pressure discharge lamp 3 was generating heat due to lighting, so the gap length of the two-terminal discharge gap 7 was increased, and the discharge starting voltage V6 was increased. therefore,
As the two-terminal discharge gap 7 discharges, the peak value of the high voltage pulse generated in the secondary winding n of the step-up transformer 8 increases.

Therefore, at the time of initial starting, where starting is easy, the high-pressure discharge lamp starts and lights up in a state where the peak value of the high-voltage pulse is small. On the other hand, when restarting, which is difficult to start, the high-pressure discharge lamp starts and lights up in a state where the peak value of the high-voltage pulse is large.

This igniter for high-pressure discharge lamps reduces the peak value of high-voltage pulses during initial startup to lower the density of high-voltage pulse generation, reducing stress on the electrodes of the high-pressure discharge lamp. , does not shorten the life of the high-pressure discharge lamp.Moreover, when restarting the high-pressure discharge lamp, the peak value of the high-voltage pulse vP is large from the beginning, and the peak value of the high-voltage pulse ■, should be waited for to become large. Therefore, the high-pressure discharge lamp 3 can be instantly restarted immediately after being turned off.

Note that even at the initial start-up, when the high-pressure discharge lamp 3 reaches the end of its life and becomes difficult to start, the gap length increases due to self-heating due to the discharge after 11a is turned on, as in the first embodiment. As a result, the peak value of the high-voltage pulse becomes high, so that the high-pressure discharge lamp can be reliably started even at the end of its life.

〔Effect of the invention〕

According to the igniter for a high-pressure discharge lamp of the present invention, at least one electrode of the two-discharge gap is made of an extreme temperature displacement conductive material that gradually increases the gap length between it and the other electrode as self-heating occurs due to discharge. Because of this structure, at the time of initial startup, it is possible to start and light the high pressure discharge lamp in a state where the peak value of the high voltage pulse is small. It does not shorten the life of the high-pressure discharge lamp, and moreover, when restarting, the peak value of the high-voltage pulse can be increased, and the high-pressure discharge lamp can be instantly restarted immediately after extinguishing. Even when restarting, high voltage pulses with larger peak values than necessary are not applied, and
At this time, too, no excessive stress is applied to the high-pressure discharge lamp, and therefore, the life of the high-pressure discharge lamp is not shortened in this respect as well.

In addition, if the two-terminal discharge gap is placed near the high-pressure discharge lamp to receive heat from the high-pressure discharge lamp, the peak value of the high-voltage pulse will be large from the beginning when the high-pressure discharge lamp is restarted, and the high-voltage pulse The high-pressure discharge lamp can be instantly restarted immediately after extinguishing without having to wait for the peak value of the lamp to become large.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of a first embodiment of the present invention;
FIG. 2 is a time chart showing the basic operation of the circuit in FIG. 1, FIG. 3 is a front view showing the specific configuration of the two-terminal discharge gap, and FIG. 4 is a time chart showing the main operations of the embodiment.
FIG. 5 is a circuit diagram showing the configuration of a second embodiment of the invention. DESCRIPTION OF SYMBOLS 1...Power source, 2...Inductive ballast, 3...High pressure discharge lamp, 4...Bypass capacitor, 5...DC high voltage generation circuit, 6...Charging circuit, 7...・2-terminal discharge gap, 8...Step-up transformer- 2-Visit/hi government equipment 3-High-pressure discharge lamp 4-Bypass capacitor 7-2-2) Discharger tube 8-J pressure transformer 1st Figure 2/C Figure 3

Claims (2)

[Claims] (1) An igniter for a high-pressure discharge lamp that applies a high-voltage pulse for starting a high-pressure discharge lamp connected to a power source via an inductive ballast, which includes a DC high-voltage generation circuit and a DC high-voltage generation circuit. A charging circuit that is charged with an output current, a two-terminal discharge gap to which a charging voltage of the charging circuit is applied, and a primary winding inserted in series in a current-carrying path from the charging circuit to the two-terminal discharge gap. A step-up transformer has a secondary winding interposed in series in the energization path from the power supply to the high-pressure discharge lamp, and the induced voltage in the secondary winding of the step-up transformer bypasses the inductive ballast to discharge the high-pressure discharge. and a bypass capacitor applied between both ends of the lamp, and a temperature-sensitive displacement type conductor in which the gap length between at least one electrode of the two-terminal discharge gap and the other electrode gradually increases as self-heating occurs due to discharge. An igniter for high pressure discharge lamps made of wood. (2) An igniter for a high-pressure discharge lamp, wherein the two-terminal discharge gap is arranged near the high-pressure discharge lamp to receive heat from the high-pressure discharge lamp.