JPH0568100U - Discharge lamp lighting device - Google Patents

Abstract

(57) [Summary] [Purpose] Automatically distinguish the type of the installed discharge lamp and apply an appropriate value of the pre-heating current, and set the pre-heating current to an appropriate value according to the type of the installed discharging lamp. By doing so, the stress applied to the discharge lamp is reduced, the time to start is shortened, and false detection is prevented. An inverter I is provided with a pre-heating unit that causes a pre-heating current to flow at a value corresponding to the discharge lamp DL having the smallest pre-heating current among a plurality of types of discharge lamps DL at the beginning of the pre-heating period.
A filament preheating current detector DT ₁ is provided which detects the filament current accompanying the preheating current conduction of the filaments f ₁ and f ₂ of the discharge lamp DL during the initial preheating current conduction period of the preceding preheating period. Lamp determination / control for determining the type of the attached discharge lamp DL based on the magnitude of the filament current, and increasing the preheating current to a value corresponding to the attached discharge lamp DL based on the determination result of the type of the discharge lamp DL. Part IC ₁ is provided.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a discharge lamp lighting device in which any one of a plurality of types of discharge lamps having filaments having different ratings is selectively mounted, and the mounted discharge lamp is preheated and then, for example, lit at a high frequency.

[0002]

[Prior Art]

FIG. 9 shows an example of a conventional inverter type preceding preheating type discharge lamp lighting device that determines the type of the installed discharge lamp and switches the detection level of the emitter wear. In FIG. 9, a discharge lamp DL is connected from a DC power source E ₁ via an inverter IV, and a capacitor C ₁ is connected between the non-power source side terminals of both filaments f ₁ and f ₂ of the discharge lamp DL.

The discharge lamp DL is composed of a fluorescent lamp or the like, and those having different ratings are selectively mounted. In this example, a normal power type discharge lamp and a power save type discharge lamp are targeted. The inverter IV preheats the discharge lamp DL and then turns on the high frequency. The capacitor C ₁ has a function of supplying a filament preheating current to the filament of the discharge lamp DL.

A primary winding of a transformer TR ₄ for detecting a lamp current is inserted in an energization path from the inverter IV to the discharge lamp DL, and the secondary winding is connected to an emitter wear detector EM. .. The emitter consumption detector EM compares the lamp current with a predetermined threshold value to reduce or stop the output of the inverter IV when the mounted discharge lamp DL is consumed. ..

In the emitter wear detector EM, the threshold value for determining the emitter wear depends on the rating of the discharge lamp DL to be mounted. Therefore, the threshold of the emitter wear detector EM is determined by determining the type of the discharge lamp DL. A circuit is required to switch between. This circuit is the lamp type determination unit EK in FIG. The lamp type determination unit EK includes a transformer TR ₃ for detecting a lamp voltage, a diode bridge DB ₃ and a smoothing capacitor C ₅ for full-wave rectifying and smoothing the secondary voltage of the transformer TR ₃ , and a discharge lamp DL. It comprises a voltage source E ₅ that sets a threshold voltage for determining the type, and a comparator CP ₁ that compares the voltage of the smoothing capacitor C _{5 with} the threshold voltage of the voltage source E ₅ . Then, after converting the lamp voltage of the installed discharge lamp DL into a DC voltage, the comparator CP ₁ compares it with the threshold voltage to determine the type of the discharge lamp DL from the difference in the lamp voltage. ..

The emitter consumption detector EK switches the threshold value for judging the consumption of the emitter depending on whether the output of the comparator CP ₁ is high or low. Fig. 10 shows other conventional inverter-type preceding preheating type discharge lamp lighting that determines whether or not the discharge lamp is installed before preheating the discharge lamp and stops the inverter operation when the discharge lamp is not installed. An example of an apparatus is shown. In FIG. 10, a discharge lamp DL is connected from a DC power source E ₁ via an inverter IV, a capacitor C ₁ is connected between the non-power source side terminals of both filaments f ₁ and f ₂ of the discharge lamp DL, and both filaments f _{1 A} capacitor C ₇ is also connected between the power source side terminals of ₁ and f ₂ .

Capacitor C₁Has a function of supplying a filament preheating current to the filament of the discharge lamp DL. Also, the capacitor C₁, C₇Also constitutes a resonant circuit. A transformer TR for current detection is provided in the energization path from the inverter IV to the discharge lamp DL._FivePrimary winding is inserted, the secondary winding is diode bridge DB_FourThrough the smoothing capacitor C₆It is connected to the. This smoothing capacitor C₆The terminal voltage of is the voltage source E₆Threshold voltage and comparator CP₂Will be compared. And the comparator CP₂The operation of the inverter IV is controlled according to the output of the inverter. The above trance TR _Five To comparator CP₂The circuits up to constitute the lamp connection determination unit ET.

A specific description will be given. In this discharge lamp lighting device, before supplying the preheating current from the inverter IV to the discharge lamp DL, the rated filament preheat is applied from the inverter IV to the resonance circuit including the discharge lamp DL, the transformer TR ₅ , and the capacitors C ₁ and C _7. High-frequency current, which is weaker than that of current, is applied to cause resonance and the magnitude of the resonance current is detected. The magnitude of the resonance current varies depending on whether the discharge lamp DL is connected or not, and the terminal voltage of the smoothing capacitor C ₆ varies depending on the magnitude of the resonance current.

The comparator CP ₂ detects the presence / absence of the connection of the discharge lamp DL, that is, the magnitude of the resonance current by the magnitude of the terminal voltage of the smoothing capacitor C ₆ , and feeds it back to the inverter IV. As a result, the inverter IV causes preheating and high frequency lighting of the discharge lamp DL when the discharge lamp DL is connected, and stops the oscillation operation when the discharge lamp DL is not connected. ..

[0010]

[Problems to be solved by the device]

 First, in the discharge lamp lighting device of FIG. 9, the type of the discharge lamp DL is determined after lighting of the discharge lamp DL. Therefore, in the discharge lamp lighting device having various types of compatible lamps, the discharge lamp DL is started at the time of starting. The filament was not preheated properly, and the stress on the filament of the discharge lamp DL was large.

In addition, the discharge lamp lighting device of FIG. 10 merely determines whether or not the discharge lamp DL is mounted, and does not determine the type (difference in rating, etc.). Further, since a small high-frequency current before the preheating of the discharge lamp DL is passed for the determination, there is a problem that it takes time to start the discharge lamp DL. Further, since the determination is made by the minute high-frequency current, if the wiring distance from the inverter IV to the discharge lamp DL becomes long, the inductance component of the wiring or the stray capacitance may affect the detection error.

An object of the present invention is to provide a discharge lamp lighting device capable of automatically discriminating the type of a mounted discharge lamp and supplying an appropriate value of the pre-heating current. Another object of the present invention is to provide a discharge lamp lighting device capable of reducing stress applied to the discharge lamp until the filament preheating current reaches an appropriate value according to the type of the discharge lamp in which the filament preheating current is mounted. .

Still another object of the present invention is to provide a discharge lamp lighting device capable of shortening the time before starting. Still another object of the present invention is to provide a discharge lamp lighting device capable of preventing erroneous detection.

[0014]

[Means for Solving the Problems]

 The discharge lamp lighting device of the present invention is one in which any one of a plurality of types of discharge lamps having different ratings having filaments is selectively installed, and the selectively installed discharge lamp is preheated for a predetermined time and then lit. is there. Then, in the early stage of the pre-heating period, a pre-heating unit for supplying the filament pre-heating current at a value corresponding to the discharge lamp with the smallest filament pre-heating current among the multiple types of discharge lamps is provided, and the pre-heating current conduction during the initial period of the pre-heating period During the period, an electrical characteristic detection means is installed to detect the electrical characteristics of the discharge lamp filament that accompanies the preheating current. Judgment control means for controlling the preceding preheating means so as to increase the filament preheating current to a value corresponding to the installed discharge lamp based on the discrimination result of the type of the discharge lamp is provided.

[0015]

[Action]

 According to the configuration of this invention, the filament preheating current flows through the discharge lamp at a value corresponding to the one having the smallest filament preheating current among the plurality of types of discharge lamps at the beginning of the preceding preheating period. During the initial preheating power distribution period of the preceding preheating period, the electrical property detection means detects the electrical property associated with the preheating current passing through the filament of the discharge lamp. Then, the type of the installed discharge lamp is determined based on the difference in the electric characteristics detected by the determination control means, and the filament preheating current is set to a value corresponding to the installed discharge lamp based on the determination result of the type of the discharge lamp. The preceding preheating means is controlled to increase.

[0016]

【Example】

An embodiment of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 is a circuit diagram of a discharge lamp lighting device according to a first embodiment of the present invention. In FIG. 1, the discharge lamp DL is connected from the DC power source E ₁ via the power switch SW ₁ and the inverter IV, and the capacitor C ₁ is connected between the non-power supply side terminals of both filaments f ₁ and f ₂ of the discharge lamp DL. Are connected.

The above-mentioned inverter IV has a function of pre-heating both filaments f ₁ and f ₂ of the discharge lamp DL and then lighting them at a high frequency, and includes the pre-heating means referred to in the claims. The discharge lamp DL is composed of a fluorescent lamp or the like, and lamps having different ratings are selectively mounted, but in this example, those having different rated powers such as 10 W, 15 W, and 20 W are targeted. The capacitor C ₁ has a function of supplying a filament preheating current to the filament of the discharge lamp DL ₁ .

When the discharge lamp DL has different ratings, the specifications of the filaments f ₁ and f ₂ also differ, and the appropriate filament preheating current value also differs. As a result, when the preceding preheating current is made to flow from the inverter IV to the discharge lamp DL, the electrical characteristics of the discharge lamp DL, such as the filament preheating current or both ends of the discharge lamp DL at the time of preheating, depend on the difference in the rating of the discharge lamp DL. The voltage (hereinafter referred to as filament preheating voltage) will also be different.

As will be described below, the type of the discharge lamp DL is determined from the inverter IV by a value corresponding to the discharge lamp DL having the smallest filament preheating current among the plurality of types of discharge lamps DL. To set the filament preheating voltage, etc. by the preheating means of the inverter IV, and in this state, measure the actual filament preheating current value or filament preheating voltage value (depending on the type of discharge lamp DL), This is achieved by discriminating between the sizes. In this example, the filament preheat current value is compared to a threshold value.

A primary winding of a transformer TR ₁ for detecting a filament preheating current for preceding preheating is inserted in an energization path from the inverter IV to the discharge lamp DL, and a secondary winding of the transformer TR ₁ is a diode bridge DB. _It is connected to the smoothing capacitor C ₂ via ₁ and the terminal voltage of the smoothing capacitor C ₂ changes to high or low depending on the magnitude of the filament preheating current. The above circuit from the transformer TR ₁ to the smoothing capacitor C ₂ constitutes the filament preheating current detection unit DT ₁ which is a means for detecting the electrical characteristics, and the discharge lamp is supplied during the preheating current energization period at the beginning of the preceding preheating period. Preheating current of the filaments f ₁ and f ₂ of the DL The electrical characteristics (filament preheating current in this example) accompanying energization are detected.

The lamp determination / control unit IC ₁ constitutes the determination control unit in the claims, and is mounted based on the difference in the filament preheating current detected by the filament preheating current detection unit DT ₁ which is the electrical characteristic detection unit. The type of the discharge lamp DL is discriminated, and based on the discrimination result of the type of the discharge lamp DL, the preheating means in the inverter IV is arranged to increase the filament preheating current to a value corresponding to the mounted discharge lamp DL. To control.

Specifically, the output voltage of the filament preheating current detector DT ₁ and the threshold voltage by the voltage source E ₂ (this threshold voltage is one less than the type of lamp to be detected) It is necessary) to determine the type of the attached discharge lamp DL, and control the output of the inverter IV based on the determination result. The operation will be described in detail below.

When the power switch SW ₁ is turned on, the inverter IV starts an oscillating operation, and a filament preheating current for preceding preheating is supplied to the filaments f ₁ and f _{2 of} the discharge lamp DL through the capacitor C ₁ . At this time, the inverter IV supplies the filament preheating voltage to the discharge lamp DL having the smallest filament preheating current among the plurality of types of discharge lamps DL that may be mounted. Is set so that a filament preheating current having an appropriate value is supplied, and the magnitude of the filament preheating current varies depending on the type of discharge lamp DL actually connected.

During the initial predetermined preheating current energization period of the preceding preheating period, the filament preheating current detection unit DT ₁ generates a DC voltage corresponding to the value of the filament preheating current across the smoothing capacitor C _2. The lamp determination / control unit IC ₁ compares the DC voltage generated across the smoothing capacitor C ₂ with one or more threshold voltages generated by the voltage source E ₂ , and determines the type of the discharge lamp DL installed. Is determined, the inverter IV is controlled based on the determination result, the advance preheating current is increased to an appropriate value according to the type of the installed discharge lamp DL, and the advance preheating is continued for a predetermined time. When the installed discharge lamp DL is the discharge lamp DL with the smallest filament preheating current, the filament preheating current value does not change.

Then, when the pre-heating is completed, the inverter IV applies a high-frequency voltage capable of lighting between both filaments f ₁ and f _{2 of} the discharge lamp DL to turn on the discharge lamp DL. At this time, the lamp power supplied from the inverter IV to the discharge lamp DL may be set to an appropriate value according to the type of the mounted discharge lamp DL. Further, the lamp power can be arbitrarily set regardless of the rated power of the mounted discharge lamp DL, and the present invention can be applied to a dimming type discharge lamp lighting device.

2 and 3 show time charts of the state of the power switch, the filament preheating current and the lamp current in the discharge lamp lighting device of FIG. FIG. 2 shows a time chart when the installed discharge lamp DL has the smallest rated power among a plurality of types of compatible lamps expected to be installed. The figure (a) shows the state of the power switch SW ₁ , the figure (b) shows the filament preheating current, and the figure (c) shows the lamp current.

In FIG. 2, when the power switch SW ₁ is turned on as shown in FIG. 2A at time t ₁ , it corresponds to the discharge lamp with the lowest wattage as shown in FIG. The filament preheating current flows. Within the initial preheating current energization period T _{1 of} this preceding preheating period, the type of the installed discharge lamp DL is determined. In this figure, the discharge lamp DL with the smallest rated power is installed, so the preceding preheating period The value of the filament preheating current in the latter preheating current conducting period T ₂ is maintained at the same level as in the preheating current conducting period T ₁ .

Then, at time t ₂ after (T ₁ + T ₂ ) time has elapsed since the power switch SW ₁ was turned on, the discharge lamp DL is lit at a high frequency as shown in FIG. Flows (lighting period T ₃ ). At this time, the lamp voltage applied from the inverter IV to the discharge lamp D L is set to a value corresponding to the discharge lamp having the lowest wattage.

FIG. 3 shows a time chart when the installed discharge lamp DL has the highest rated power among a plurality of types of compatible lamps expected to be installed. The figure (a) shows the state of the power switch SW ₁ , the figure (b) shows the filament preheating current, and the figure (c) shows the lamp current. In FIG. 3, when the power switch SW ₁ is turned on as shown in FIG. 3A at time t ₁ , the filament corresponding to the discharge lamp with the lowest wattage is provided as shown in FIG. 3B. Preheat current flows. Within the initial preheating current energization period T ₁ of the preceding preheating period, the type of the installed discharge lamp DL is determined. In this figure, the discharge lamp DL with the highest rated power is installed, so the preceding preheating period The value of the filament preheating current in the latter preheating current conducting period T ₂ is larger than that in the preheating current conducting period T ₁ .

After the power switch SW ₁ is turned on, at time t ₂ when (T ₁ + T ₂ ) time has elapsed, the discharge lamp DL is lit at a high frequency as shown in FIG. Flows (lighting period T ₃ ). At this time, the lamp voltage applied from the inverter IV to the discharge lamp D L is set to a value corresponding to the discharge lamp having the highest wattage, and therefore has a higher level than the lamp current in FIG. 2 (c).

According to this discharge lamp lighting device, during the initial preheating current energization period T _{1 of} the preceding preheating period, a filament for detecting the filament preheating current accompanying the energization of the preheating current of the filaments f ₁ and f ₂ of the discharge lamp DL. A preheating current detector DT ₁ is provided, and the type of the discharge lamp DL installed is determined based on the difference in the detected filament preheating current, and the installed discharge lamp DL is supported based on the determination result of the type of the discharge lamp DL. Since the lamp determination / control unit IC ₁ that increases the filament preheating current to the above value is provided, it is possible to automatically determine the type of the installed discharge lamp DL and pass the appropriate preheating current.

When determining the magnitude of the filament preheating current, which is the electrical characteristic of the discharge lamp DL, the discharge lamp DL is set to a value corresponding to the discharge lamp DL having the smallest filament preheating current among the plurality of types of discharge lamps DL. A filament preheating current is applied to the discharge lamp DL and the filament preheating current is increased to a value corresponding to the installed discharge lamp DL based on the determination result of the type of the discharge lamp DL. It is possible to reduce the stress exerted on the discharge lamp DL until it reaches an appropriate value according to the above.

Further, when determining the magnitude of the filament preheating current of the discharge lamp DL, the filament of the discharge lamp DL is set to a value corresponding to the discharge lamp DL having the smallest filament preheating current among the plurality of types of discharge lamps DL. A preheating current is passed, and the filaments f ₁ and f ₂ are also preheated to some extent at this time, so that the time until starting can be shortened.

Further, of the plurality of types of discharge lamps DL, a value corresponding to the discharge lamp DL having the smallest filament preheating current, that is, a discharge lamp with a filament preheating current flowing at a relatively large value. Since the magnitude of the filament preheating current of the DL is determined, even if the wiring distance between the inverter IV and the discharge lamp DL becomes a little longer, it is less affected by the inductance component of the wiring, the stray capacitance, etc., and erroneous detection is prevented. be able to.

[Second Embodiment] FIG. 4 shows a circuit diagram of a discharge lamp lighting device according to a second embodiment of the present invention. This discharge lamp lighting device detects a filament preheating voltage in place of the filament preheating current as an electric characteristic, and is provided with a filament preheating voltage detection unit DT ₂ in place of the filament preheating current detection unit DT ₁ in FIG. ing.

The filament preheating voltage detection unit DT ₂ detects the filament preheating voltage with the transformer TR ₂ , the diode bridge DB ₂ and the smoothing capacitor C ₃ , and detects it as a plurality of threshold voltages by the voltage source E _3. The type of the discharge lamp DL mounted is compared by the lamp determination / control unit IC ₂ and the inverter IV is controlled in the same manner as in the first embodiment.

Operationally, it differs from the first embodiment in that the magnitudes of the filament preheating voltage are compared in order to determine the type of the discharge lamp DL, but other points are the same as in the first embodiment. It is similar to the embodiment. 5 and 6 show time charts of the state of the power switch, the filament preheating current and the lamp current in the discharge lamp lighting device of FIG.

FIG. 5 shows three types of compatible lamps A, B, and C (for example, 10 W, 15 W, and 20 W) in which the mounted discharge lamp DL is expected to be mounted (the wattage has a relationship of A <B <C. () Shows the time chart when the lamp B with the rated power in the middle is mounted. The figure (a) shows the state of the power switch SW ₁ , the figure (b) shows the filament preheating current, and the figure (c) shows the lamp current.

In FIG. 5, when the power switch SW ₁ is turned on as shown in FIG. 5A at time t ₁ , it corresponds to the lamp A having the lowest wattage as shown in FIG. The level X ₁ filament preheating current flows. The type of the mounted lamp is determined within the initial preheating power distribution period T _{1 of the} preceding preheating period. However, since it is detected that the lamp B with the rated power in the middle is mounted, The value of the filament preheating current in the latter preheating power distribution period T ₂ is higher than that in the preheating current energization period T _{1 and} reaches the level X ₂ .

At time t ₂ after (T ₁ + T ₂ ) time has elapsed since the power switch SW ₁ was turned on, as shown in FIG. 6C, the discharge lamp DL is lit at high frequency and the level of the level Y ₂ changes. Pump current flows (lighting period T ₃ ). At this time, the lamp voltage applied from the inverter IV to the discharge lamp DL is set to a value corresponding to the lamp B having the middle wattage. The level Y ₁ is the value of the lamp current when the lamp A is mounted.

FIG. 6 shows three types of compatible lamps A, B, C (for example, 10 W, 15 W, 20 W) in which the installed discharge lamp DL is expected to be installed (the wattage has a relationship of A <B <C. ), The time chart when the lamp C with the maximum rated power is installed is shown. The figure (a) shows the state of the power switch SW ₁ , the figure (b) shows the filament preheating current, and the figure (c) shows the lamp current.

In FIG. 6, when the power switch SW ₁ is turned on as shown in FIG. 6A at time t ₁ , it corresponds to the lamp A having the lowest wattage as shown in FIG. The level X ₁ filament preheating current flows. The type of the installed lamp is determined within the initial preheating power distribution period T _{1 of the} preceding preheating period. However, since it is detected that the lamp C with the maximum rated power is installed, the preheating period The value of the filament preheating current in the latter preheating current conducting period T ₂ becomes higher than that in the preheating current conducting period T ₁ and reaches the level X ₃ .

At time t ₂ after (T ₁ + T ₂ ) time has elapsed since the power switch SW ₁ was turned on, as shown in FIG. 7C, the discharge lamp DL is lit at a high frequency and the level of Y ₃ changes. Pump current flows (lighting period T ₃ ). At this time, the lamp voltage applied from the inverter IV to the discharge lamp DL is set to a value corresponding to the lamp C having the highest wattage. In addition, it goes without saying that a value corresponding to the lamp A or B may be set by turning on the dimming light.

The effects of this embodiment are similar to those of the first embodiment. [Third Embodiment] FIG. 7 shows a circuit diagram of a discharge lamp lighting device according to a third embodiment of the present invention. This discharge lamp lighting device is configured to perform pre-heating of the filaments f ₁ and f ₂ of the discharge lamp DL by a DC pre-heating method. That is, this discharge lamp lighting device forms a path for passing a DC filament preheating current from the DC power source E through the power source switch SW ₂ and the inductor L _1, and also supplies the DC power source E ₁ through the power source switch SW ₃ to the DC power source E _1. The inverter IV is connected, and the output end of the inverter IV is connected to the discharge lamp DL.

A capacitor C inserted on the output side of the inverter IV_FourIs for DC component cutting (for high frequency component bypass). Inductor L₁Is for cutting high frequency components (for bypassing DC components). Also, the resistance R₁Is for detecting the filament preheating current. Filament preheating current detector DT₃Is the resistance R for detecting the filament preheating current₁And a voltage source E that generates a plurality of threshold voltages_FourAnd lamp determination / control unit IC ₃ Consists of. The operation is the resistance R₁The lamp type is determined by comparing the terminal voltage and the threshold voltage of the inverter, and according to the determination result, a signal designating the levels of the preheating current and the lamp current is supplied to the inverter IV. Therefore, the settings of the preheating current and the lamp current are changed. This operation is similar to each of the above-mentioned embodiments.

FIG. 8 shows a time chart of the state of the switches, the filament preheating current and the lamp current in the discharge lamp lighting device of FIG. FIG. 8 shows three types of compatible lamps A, B, and C (for example, 10 W, 15 W, and 20 W) in which the mounted discharge lamp DL is expected to be mounted (the wattage has a relationship of A <B <C). Shows the time chart when the lamp B with the rated power in the middle is mounted. The figure (a) shows the state of the switch SW ₂ , the figure (b) shows the state of the switch SW ₃ , the figure (c) shows the filament preheating current, and the figure (d) shows the lamp current. ing.

In FIG. 8, when the switch SW ₂ is turned on as shown in FIG. 8A at time t ₁ , the level corresponding to the lamp A having the lowest wattage is shown as shown in FIG. 8C. filament preheating current Le X ₁ flows. The type of the mounted lamp is discriminated within the initial preheating current conduction period T _{1 of} this preceding preheating period. However, since it is detected that the lamp B with the rated power in the middle is mounted, the preceding preheating period is detected. the value of the filament preheating current in the preheating electric distribution electrostatic period T ₂ of the late also increased from the preheating current conduction period T _1, a level X _2. Level X ₃ is a level corresponding to the lamp B having the rated power in the middle.

After the power switch SW ₁ is turned on, at time t ₂ when (T ₁ + T ₂ ) has elapsed, the switch SW ₂ is turned off as shown in FIG. Thus, when the switch SW ₃ is turned on, the discharge lamp DL is lit at high frequency and a lamp current of level Y ₂ flows (lighting period T ₃ ) as shown in FIG. At this time, the lamp voltage applied from the inverter IV to the discharge lamp DL is set to a value corresponding to the lamp B having the middle number of Watts.

At time t ₃ , when the switch SW ₃ is turned off as shown in FIG. 7B, the discharge lamp DL is turned off and the lamp current stops flowing as shown in FIG. In the above-mentioned embodiment, the filament preheating is performed at a high frequency, and if the wiring distance is long, it is greatly affected by the stray capacitance of the wiring, and the filament preheating current cannot be accurately detected. In some cases, the filaments f ₁ and f ₂ are preheated with direct current and the magnitude of the direct current filament preheating current is determined in the present embodiment. Therefore, between the inverter IV and the discharge lamp DL. Even if the wiring distance is long, there is no attenuation of the preheating current due to stray capacitance, the filament preheating current can be accurately detected, and the risk of misjudging the lamp type is extremely low.

The other effects are the same as those of the above-mentioned embodiments. There is no particular limitation on the lengths of the preheating current energizing periods T ₁ and T ₂ in the early and late stages of the preceding preheating period. Also, the voltage applied to the discharge lamp DL at time t ₃ may be set to a value corresponding to the discharge lamp DL each time, or the maximum starting voltage of the compatible lamp may be applied. Further, it is not limited to the high frequency voltage.

Further, the filament preheating current at the time of lighting may be any value as long as it is smaller than the level of the latter preheating current conducting period T ₂ . Further, the discharge lamp DL may be in a dimming state during lighting.

[0052]

[Effect of the device]

 According to the discharge lamp lighting device of this invention, during the initial preheating current energization period of the preceding preheating period, the electric characteristic detection means for detecting the electric characteristic accompanying the preheating current energization of the filament of the discharge lamp is provided, and the detected electrical characteristics are detected. Based on the difference in the characteristics, the type of the installed discharge lamp is determined, and the determination control means for increasing the filament preheating current to the value corresponding to the installed discharge lamp based on the determination result of the type of the discharge lamp is provided. It is possible to automatically determine the type of discharge lamp that has been worn and to supply an appropriate value of the preheating current.

When determining the electrical characteristics of the discharge lamp, the filament preheating current is passed through the discharge lamp at a value corresponding to the discharge lamp with the smallest filament preheating current among the plurality of types of discharge lamps. Since the filament preheating current is increased to a value corresponding to the installed discharge lamp based on the determination result, the stress applied to the discharge lamp until the filament preheating current reaches an appropriate value according to the type of the installed discharge lamp. Can be reduced.

Further, when determining the electrical characteristics of the discharge lamp, the filament preheating current is supplied to the discharge lamp at a value corresponding to the discharge lamp with the smallest filament preheating current among the plurality of types of discharge lamps. Since the filament is preheated to some extent, the start-up time can be shortened. Furthermore, among the multiple types of discharge lamps, the value corresponding to the discharge lamp with the least filament preheating current, that is, the electrical characteristic of the discharge lamp is determined when the filament preheating current is applied to the discharge lamp with a relatively large value. Even if the wiring distance between the inverter and the discharge lamp becomes a little longer, it is less affected by the wiring inductance component, stray capacitance, etc., and erroneous detection can be prevented.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a discharge lamp lighting device according to a first embodiment of the present invention.

FIG. 2 is a time chart showing the operation of the discharge lamp lighting device of FIG.

3 is a time chart showing the operation of the discharge lamp lighting device of FIG.

FIG. 4 is a circuit diagram showing a configuration of a discharge lamp lighting device according to a second embodiment of the present invention.

5 is a time chart showing the operation of the discharge lamp lighting device of FIG.

FIG. 6 is a time chart showing the operation of the discharge lamp lighting device of FIG.

FIG. 7 is a circuit diagram showing a configuration of a discharge lamp lighting device according to a third embodiment of the present invention.

8 is a time chart showing the operation of the discharge lamp lighting device of FIG.

FIG. 9 is a circuit diagram showing a conventional example of a discharge lamp lighting device.

FIG. 10 is a circuit diagram showing another conventional example of the discharge lamp lighting device.

[Explanation of symbols]

E ₁ DC power supply SW ₁ power switch IV inverter DL discharge lamp C ₁ capacitor f ₁ and f ₂ filament DT ₁ filament preheating current detection unit IC ₁ lamp judgment / control unit

Claims (1)

[Scope of utility model registration request] 1. A discharge lamp lighting device in which any one of a plurality of types of discharge lamps having different ratings having filaments is selectively mounted, and the selectively mounted discharge lamp is preheated for a predetermined time and then lit. In the beginning of the pre-heating period, a pre-heating means for supplying a filament pre-heating current with a value corresponding to the discharge lamp with the smallest filament pre-heating current among the plurality of types of discharge lamps is provided, Provided with an electrical characteristic detection means for detecting the electrical characteristics associated with the preheating current conduction of the filament of the discharge lamp during the period, to determine the type of the discharge lamp mounted based on the difference in the electrical characteristics detected by this electrical characteristic detection means, Increase the filament preheating current to a value corresponding to the installed discharge lamp based on the result of this discharge lamp type determination. The discharge lamp lighting apparatus characterized in that a determination control means for controlling said preheating means.