JPH07254492A - Discharge lamp lighting control system - Google Patents

Abstract

PURPOSE:To avoid an unnatural impression by eliminating a discharge lamp from instantaneously becoming high in light flux even when they are lighted at a low light flux after preheating. CONSTITUTION:A lighting circuit 1 is an inverter circuit, and supplies electric power to discharge lamps L1 and L2 through a resonance circuit, and adjusts impression voltage by varying an output frequency. After electric power supply is applied, filaments (f1 and f2) are preheated in a specific preheating period. After a preheating period is finished, pulse voltage in a degree of generating very small discharge is intermittently impressed on the discharge lamps L1 and L2 in a specific starting period, and afterwards, light dimming voltage to obtain desired light output is impressed on the discharge lamps L1 and L2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting control system.

[0002]

2. Description of the Related Art Conventionally, in a discharge lamp having a filament such as a fluorescent lamp, a preheating period for preheating the filament with an electric power that does not light the discharge lamp is provided, and after the preheating, a discharge state is set. An electric lamp lighting control method is known. That is, during the preheating period, the potential difference between the electrodes of the discharge lamp is set low enough to prevent the discharge from starting, and a preheating current is applied to the filament, and after preheating the filament, the potential difference between the electrodes of the discharge lamp is increased to cause discharge. By starting the, the transition to the lighting state is facilitated. The preheating period is usually set to be a fixed time. After the preheating period ends, a sufficiently high starting voltage is applied for a short period of time so that the transition to the lighting state is facilitated, and the transition to the lighting state is performed.

By the way, it can be considered that this type of discharge lamp lighting control system is adopted in a lighting circuit capable of adjusting the energy supplied to the discharge lamp according to an external signal to dimm the discharge lamp. As a dimmable lighting circuit,
There is a configuration that uses an inverter circuit equipped with a switching element as a lighting circuit and supplies energy to a discharge lamp through a resonance circuit. By adjusting the duty ratio between the ON period and the OFF period of the switching element, dimming is possible. There is one configured to enable. In this configuration, the impedance of the resonance circuit changes by controlling the duty ratio between the ON period and the OFF period of the switching element, and the energy supplied to the discharge lamp can be adjusted. To control the duty ratio, for example, a voltage-duty ratio conversion circuit (hereinafter referred to as a conversion circuit) that converts a DC voltage into a duty ratio may be used to control the DC voltage input to the conversion circuit.

That is, in order to enable the lighting control for providing the preheating period as described above and the dimming control for dimming by the external signal, as shown in FIG. A preheating control circuit 4a that generates a voltage signal that controls application and a dimming control circuit 4b that generates a dimming signal that is a voltage signal according to an external signal are provided, and the preheating control circuit 4a and the dimming control circuit 4b are provided. It is conceivable that the output of the maximum voltage output circuit 4d, which adopts the larger one of the voltage signals output from, is input to the conversion circuit. Now, assuming that the lighting circuit is configured so that the higher the input voltage to the conversion circuit, the larger the power supplied to the discharge lamp, the preheating control circuit 4a performs the preheating period time and the preheating period. In the dimming control circuit 4b, a low voltage that allows preheating is output, and the starting voltage is generated in a pulse form (hereinafter, referred to as a starting pulse) for a short time after the preheating period is finished to stop the output. Then, the external signal is converted into a dimming signal which is a voltage signal, and the dimming signal is output after the end of the preheating period.

[0005]

By the way, in the preheating control circuit 4a, the starting pulse is generated only once after the end of the preheating period to shift the discharge lamp to the lighting state. Therefore, the energy of the starting pulse is set to be sufficiently large. Then, it is necessary to surely shift from the preheating state to the lighting state. On the other hand, when dimming control is possible, if the luminous flux output from the discharge lamp is set to the minimum, the input voltage to the conversion circuit may be lower than that during preheating. That is, the input voltage to the conversion circuit during lighting is lower than that during preheating. this is,
This is because a high starting voltage is required to shift from the non-discharging state to the discharging state, but if the discharging is started, the discharging state can be maintained at a voltage lower than the starting voltage.

However, in the fade-in control in which the output luminous flux of the discharge lamp is gradually increased with the passage of time from the start of lighting, as shown in FIG. 8A, preheating after the power is turned on at time t _0. In the period τp, the voltage signal output from the dimming control circuit 4b may be lower than the voltage signal output from the preheating control circuit 4a immediately after the discharge lamp is started at time t ₁ . When the input voltage to the conversion circuit changes as shown in FIG. 8A, as shown in FIG. 8B, the discharge lamp is lit by the application of the start pulse after the end of the preheating period τp, and the output light flux of the discharge lamp is changed. Changes so that it rises only for a short period of time when the starting pulse is applied, and thereafter becomes low. In other words, the fade-in control instantly brightens, then darkens and gradually brightens, which gives a problem that the fade-in control gives an unnatural impression. There is also a problem from the viewpoint of eye health.

The present invention is intended to solve the above-mentioned problems, and even when lighting with a low luminous flux after preheating, the luminous flux does not momentarily become a high luminous flux, and the lighting state is changed without giving an unnatural impression. It is intended to provide a discharge lamp lighting control system that can be changed.

[0008]

The invention of claim 1 uses a lighting circuit capable of dimming by adjusting the voltage applied to a discharge lamp having a filament, and the filament is preheated after the power is turned on and then is lit. In the discharge lamp lighting control method of shifting to a discharge lamp, a pulse voltage to the extent that a slight discharge is generated in the discharge lamp is intermittently and repeatedly applied to the discharge lamp before shifting to the lighting state, and a desired voltage is applied after applying the pulse voltage a plurality of times. It is characterized in that a voltage for light control for obtaining an output luminous flux is applied to the discharge lamp.

According to a second aspect of the present invention, in the first aspect of the invention, after the discharge lamp shifts to the lighting state, the larger one of the pulse voltage and the voltage for dimming is applied, and the discharge lamp is in the lighting state. It is characterized in that the peak value of the pulse voltage is set to be higher before the shift to (1) and the time interval for generating the pulse voltage is set to be larger than that after the shift to the lighting state.

According to a third aspect of the present invention, in the first aspect of the invention, after the preheating period for preheating the discharge lamp, a voltage substantially equal to the minimum luminous flux of the discharge lamp during dimming control and a pulse set higher than this voltage are set. A voltage for dimming is provided to provide a starting period in which a voltage and a voltage are alternately applied to the discharge lamp, and to make the discharge lamp the minimum luminous flux at the end of the starting period and to raise the output luminous flux to a desired output luminous flux with the passage of time. It is characterized in that the higher voltage of the pulse voltage is applied to the discharge lamp.

According to a fourth aspect of the present invention, in addition to the first or third aspect of the present invention, an incandescent lamp for illuminating an illumination space by the discharge lamp is added, and at the same time the voltage for dimming is applied to the discharge lamp. It is characterized by starting power supply to the.

[0012]

According to the first aspect of the invention, the pulse voltage, which is such that a slight discharge is generated in the discharge lamp, is intermittently and repeatedly applied to the discharge lamp before the transition to the lighting state. The discharge lamp is gradually turned to the lighting state instead of being surely lit with one starting voltage, and even if the low luminous flux is set at the time of shifting to the lighting state, it is momentary. It does not have a high luminous flux.
That is, even in the case of performing fade-in control or the like, the unnatural phenomenon that the light flux once becomes high and then becomes low at the start of lighting does not occur. Moreover, since the pulse voltage is repeatedly applied, it is possible to gradually shift to the lighting state and surely shift to the lighting state.

According to the second aspect of the present invention, the peak value of the pulse voltage is lowered and the pulse voltage generation interval is set larger before the transition to the lighting state than after the transition to the lighting state. Before the transition to the state, it is possible to facilitate the transition to the lighting state by facilitating the generation of ions by a high voltage at a high voltage, and to reduce the unnecessary pulse voltage in the lighting state to suppress flicker.

A third aspect of the present invention is a preferred embodiment, in which the lighting state is changed after the preheating period and the starting period, and after the starting period, fade-in control is performed to output a desired luminous flux. To raise. The invention of claim 4 is a preferred embodiment, wherein when an incandescent lamp is used in combination with the discharge lamp, power is supplied to the incandescent lamp from the time when the discharge lamp is switched to the lighting state, so that prior to the discharge lamp. This prevents the feeling of strangeness caused by the incandescent lamp lighting.

[0015]

【Example】

(Embodiment 1) In this embodiment, as shown in FIG. 1, an inverter circuit is used as the lighting circuit 1 and the duty ratio between the ON period and the OFF period of the switching element provided in the lighting circuit 1 is controlled. Discharge lamps L ₁ and L ₂
The energy supplied to the discharge lamp L can be adjusted, and two discharge lamps L
_1, L ₂ although is lit, the configuration of the lighting circuit 1, configured to adjust the supply energy to the discharge lamp L _1, L _2, the discharge lamp L _1, lights number of L ₂ shall not be limited thereto Instead, the technical idea of the present invention can be applied to the lighting circuit 1 for preheating and dimming a discharge lamp including a filament.

The lighting circuit 1 of this embodiment is a commercial AC power supply A.
C is a diode bridge DB and a smoothing capacitor C ₃
A power source is a DC power source rectified and smoothed by the power source circuit 2 and a pair of transistors Q ₁ and Q ₂ whose emitter and collector are connected in series are provided as switching elements, and a series circuit of both transistors Q ₁ and Q ₂ is smoothed. It is connected across the capacitor C ₃ . Freewheeling diodes D ₁ and D ₂ are connected in antiparallel between the emitters and collectors of the transistors Q ₁ and Q ₂ , respectively. Also,
The emitter of the transistor Q ₁ - is between the collector resistor R ₁
Are connected in parallel, and a series circuit of a pair of resistors R ₂ and R ₃ is connected in parallel between the emitter and collector of the transistor Q ₂ . Further, a series circuit of the primary winding of the current transformer CT and the load circuit 3 is connected in parallel between the emitter and collector of the transistor Q ₂ .

The load circuit 3 has a choke coil CH having a center tap, the center tap of the choke coil CH is connected to the lighting circuit 1, and both ends of the choke coil CH are connected to the discharge lamps L ₁ and L _2. . That is, the power supplied from the lighting circuit 1 is distributed to the two discharge lamps L ₁ and L ₂ by the choke coil CH. As the discharge lamps L ₁ and L ₂ , a fluorescent lamp having a pair of filaments f ₁ and f ₂ is used, and one end of each filament f ₁ of each of the discharge lamps L ₁ and L ₂ is a choke coil. One end of the filament f ₂ connected to CH is connected to the lighting circuit 1 through capacitors C ₁ and C ₂ for cutting DC, respectively. Further, capacitors C ₄ and C ₅ are connected between the other ends of both filaments f ₁ and f ₂ .

By the way, the transistor Q _{2 of the} lighting circuit 1
Is turned on by a control signal from the control circuit 4 to the base.
The transistor Q ₁ is controlled to be turned off, and the series circuit of the secondary winding of the current transformer CT and the resistor R ₄ and the resistor R ₅ are connected between the base and the emitter of the transistor Q ₁ to connect the secondary winding of the current transformer CT. On / off control is performed according to the output current. The control circuit 4 uses the resistance R described above.
₂ and R ₃ is provided with a comparator CP ₁ which compares the potential of the connection point with a preset reference voltage Vref, and the inverting input terminal of the comparator CP ₂ is connected to the output terminal of the comparator CP ₁ via the diode D _4. is there. The comparator CP ₁ sets its output to the L level when the potential at the connection point of the resistors R ₂ and R ₃ exceeds the reference voltage Vref. The inverting input terminal of the comparator CP ₂ is connected to the connection point between the resistor R ₆ and the capacitor C ₆ connected in series, and the stabilized control power supply voltage Vdd is applied to both ends of this series circuit. The output terminal of the comparator CP ₁ is also connected to the base of the transistor Q ₂ via the diode D _3, and the output terminal of the comparator CP ₂ is connected to the base of the transistor Q ₂ via the resistor R ₇ . The non-inverting input terminal of the comparator CP _2, the voltage - the duty converting circuit (hereinafter, abbreviated as converting circuit) output voltage is applied.

According to the above configuration, when the power is turned on, the voltage is applied to the series circuit of the resistors R _{1 to} R ₃ , but the voltage applied to the inverting input terminal of the comparator CP _{1 at} this time is less than the reference voltage Vref. Is also set low, and the output of the comparator CP ₁ becomes H level. Therefore, the transistor Q ₂ is forward-biased through the diode D ₃ to turn on the transistor Q ₂ , and at the same time, the capacitor C ₆ is charged through the resistor R ₆ . Here, as will be described later, since the conversion circuit outputs a constant positive voltage, the resistance R ₆
Until time determined by the capacitor C ₆ has elapsed is lower than the output voltage of the terminal voltage conversion circuit of a capacitor C _6, the output of the comparator CP ₂ becomes H level. That is, the transistor Q ₂ is kept in the on state for a certain period of time after the power is turned on until the terminal voltage of the capacitor C ₆ rises.

[0020] When the terminal voltage of the capacitor C ₆ exceeds the output voltage of the converter circuit rises transistor Q ₂ is because turned off, the resistor R ₁ - 1 winding of the current transformer CT - choke coil CH- capacitor C ₄ , C ₅ -Capacitor C
_A current flows through the path of ₁ , C _{2, and} the transistor Q is generated by the current induced in the secondary winding of the current transformer CT.
_A current flows in the forward direction to the base of ₁ . That is, the transistor Q ₁ is controlled in the ON direction and the resistance R ₁
Additionally the transistor Q ₁ emitter - because so current flows also between the collector, the transistor Q ₁ is turned on. During the transistor Q ₁ is turned on, the potential at the connection point of the resistors R _2, R _3, the reference voltage is higher than Vref, the comparator CP ₁ of the output transistor Q ₂ through the diode D ₃ from the L level Goes to the L level, and as a result, the transistor Q ₂ is kept off. At the same time, the capacitor C ₆ is discharged through the diode D ₄ at the same time.

[0021] Then, the current flowing through the primary winding of the current transformer CT is saturated, the transistor Q ₁ and the base current is stopped to the transistor Q ₁ is turned off. At this time, the current transformer CT keeps the current flowing through the primary winding through the diode D ₂ due to the stored energy and discharge lamps L ₁ , L
Make sure that the current supplied to ₂ is not cut off suddenly. When the transistor Q ₁ is turned off, the potential at the connection point of the resistors R ₂ and R ₃ is lowered and becomes lower than the reference voltage Vref, the output of the comparator CP ₁ becomes H level, and the transistor Q ₂ is turned on. , The capacitor C ₆ is charged again, and the transistor Q ₂ is kept on until the terminal voltage of the capacitor C ₆ exceeds the output voltage of the conversion circuit. Next, when the transistor Q ₂ is turned off, the current transformer CT keeps the current flowing through the diode D _{1 by the} stored energy so that the current to the discharge lamps L ₁ and L ₂ is not suddenly cut off.

As described above, the ON period of the transistor Q ₂ of the lighting circuit 1 is determined by the relationship between the time constant of the resistor R ₆ and the capacitor C ₆ and the output voltage of the conversion circuit, and the OFF period of the transistor Q ₂ is determined. Becomes almost constant depending on the configuration of the load circuit 3 and the capacity of the current transformer CT. That is,
With the above configuration, by changing the output voltage of the conversion circuit, the duty ratio between the ON period and the OFF period of the transistors Q ₁ and Q ₂ which are switching elements is controlled, and only the ON period of the transistor Q ₂ is controlled. As a result, the frequency is controlled. The load circuit 3 includes a series resonance circuit including a choke coil CH and capacitors C ₁ and C ₂ , and the discharge lamps L ₁ and L ₂ are supplied with power through the series resonance circuit. Therefore, the ON period of the transistors Q ₁ and Q ₂ is reduced. If the frequency of the power supplied to the load circuit 3 is changed by changing the duty ratio between the OFF period and the OFF period, the power supplied to the discharge lamps L ₁ and L ₂ will change. Here, the frequency given to the load circuit 3 is set to be higher than the resonance frequency of the series resonance circuit, and the ON period of the transistor Q ₂ becomes longer as the output voltage of the conversion circuit rises and is supplied to the load circuit 3. When the frequency approaches the series resonance frequency, the electric power supplied to the discharge lamps L ₁ and L ₂ is increased.

Therefore, as described above, the output of the conversion circuit
Discharge lamp L by controlling the voltage₁, L₂Supply power to
The conversion circuit of this embodiment can be adjusted at a constant time.
The preheating period between
Preheat control circuit 4a that outputs a pressure signal and the end of the preheat period
The start voltage signal is generated during the start period set later.
Dynamic control circuit 4c and a voltage signal that is a voltage signal according to an external signal.
Dimming control circuit 4b that outputs an optical signal and preheating control circuit 4
a, the start control circuit 4c, the output voltage of the dimming control circuit 4b
Maximum voltage output circuit 4 that outputs the highest voltage
and d. The maximum voltage output circuit 4d is
Thermal control circuit 4a, start control circuit 4c, dimming control circuit 4b
Diodes with each output voltage applied to the anode
D_Five~ D ₇Equipped with a diode D_Five~ D₇The cathode of
Resistor R commonly connected and grounded at one end₈The other end of
It has a configuration connected to. Therefore, the maximum voltage output
Diode D on path 4d_Five~ D₇The cathode of the preheating system
Control circuit 4a, start control circuit 4c, dimming control circuit 4b
The highest output voltage is output.
This voltage is used by the comparator CP₂Mark the non-inverting input end of
Add.

The output voltage of the preheat control circuit 4a is as shown in FIG.
(A), the held constant voltage e ₁ for preheating the constant preheating period .tau.p, after the end of the preheating period .tau.p is adapted to be kept at a constant voltage lower e ₂ than the voltage e ₁ ing. This voltage e ₂ is set to be substantially equal to the voltage at which the output luminous flux of the discharge lamps L ₁ and L ₂ is minimized during dimming control.

As shown in FIG. 2B, the starting control circuit 4c is stopped during the preheating period τp, and after the preheating period τp ends, the voltage e ₃ higher than the voltage during preheating is intermittently shortened. It is configured to output by time. Here, since the output voltage of the starting control circuit 4c has a pulse shape, it will be referred to as a pulse voltage hereinafter. The peak value e ₃ of the pulse voltage is set to be lower than the voltage for maximizing the output luminous flux of the discharge lamps L ₁ and L ₂ during dimming control and higher than the voltage for minimizing the output luminous flux. It The peak value e ₃ of the pulse voltage is set sufficiently lower than the peak value of the conventional starting pulse. Furthermore, during the period of generation of one pulse voltage, the discharge lamp L
It is set so that ₁ and L ₂ do not immediately switch to the lighting state. That is, the energy of one pulse voltage is set so that a minute discharge is generated between the filaments f ₁ and f ₂ of the discharge lamps L ₁ and L ₂ , and the interval is such that the ions generated by the minute discharge do not disappear. Is set to such an extent that a complete discharge state can be achieved by intermittently applying a plurality of pulse voltages.

The pulse voltage from the starting control circuit 4c continues to be generated after the preheating period τp ends, and as shown in FIG. 2 (c), the dimming control circuit 4b has a constant starting period after the preheating period τp. When τs elapses, the output voltage is gradually increased so as to raise it to the dimming level set by the external signal. FIG. 2C shows a voltage e ₄ corresponding to the lowest luminous flux and a voltage e ₅ corresponding to the highest luminous flux during dimming control.

With the above configuration, the maximum voltage output circuit 4
The output voltage of d is as shown in FIG. That is,
In the preheating period τp, the output voltage e of the preheating control circuit 4a set higher than the voltage e ₄ corresponding to the minimum luminous flux during dimming control.
Only ₁ is output. After the start-up period τp, the output voltage of the preheat control circuit 4a becomes the voltage e ₂ (≈e ₄ ) set to about the voltage e ₄ corresponding to the minimum luminous flux during dimming control. When the output voltage from the preheating control circuit 4a becomes the voltage e ₂ , a pulse voltage is applied from the starting control circuit 4c, so that the starting period τs until the output of the dimming control circuit 4b starts rising after the end of the preheating period τp. Becomes the voltage e ₃ when the pulse voltage is generated, and becomes the voltage e ₂ in the other periods. Therefore, during the starting period τs, the discharge lamp L
₁ and L ₂ are almost not lit, or even if lit, the light flux becomes low on average, close to the minimum light flux during dimming control, and compared with the conventional case where one starting pulse shifts to the lighting state. Then, it is possible to shift to the lighting state without causing an instantaneous high luminous flux state. When the starting period τs ends and the lighting period τl starts, the dimming control circuit 4b
Whichever is higher than the output voltage of the start control circuit 4c is output from the maximum voltage output circuit 4d. Therefore,
If the light flux is adjusted to a low luminous flux, the pulse voltage is output intermittently, and if the cycle of the pulse voltage is long, the discharge lamps L ₁ , L ₂
Since the output luminous flux of flicker, the pulse voltage is 500 to 10
It is desirable to set to 00 Hz.

By the way, in the above embodiment, the preheating period τp
Although the pulse voltage application is started after the end of, the pulse voltage application may be started during the preheating period τp and the voltage e ₁ is being output from the conversion circuit. The application of voltage may be started. further,
The dimming signal is not after the start period τs but at the start period τs.
It may be given from the start of.

Further, as shown in FIG. 3 (a), the pulse voltage output from the start control circuit 4c is increased with the passage of time in the starting period τs, and then the pulse voltage is lowered to shift to the lighting period τl. Alternatively, as shown in FIG. 3B, in the starting period τs, the lighting period τl
The pulse voltage may be set higher than the pulse voltage, and the generation interval of the pulse voltage may be set shorter in the lighting period τl than in the starting period τs.

(Embodiment 2) In this embodiment, as shown in FIG. 4, a fluorescent lamp apparatus 5 using a fluorescent lamp which is a discharge lamp and an incandescent lamp using an incandescent lamp are provided in one space area such as an indoor space. The lighting fixture 6 is arranged, and the dimming control device 7 for giving an external signal for dimming is connected to the fluorescent lighting fixture 5 and the incandescent lighting fixture 6 so as to perform dimming control for the fluorescent lighting and the incandescent lighting. Here is an example: In such a configuration, the same circuit as that of the first embodiment is incorporated in the fluorescent lamp fixture 5 to adopt the same lighting control system, and the incandescent lamp fixture 6 also adopts the same lighting control system as the fluorescent lamp fixture 5. Then, as shown in FIG. 6, the incandescent lamp shown in FIG. 6B is lit with a low luminous flux before the fluorescent lamp shown in FIG. 6A is lit, which is unnatural.

Therefore, in this embodiment, when the incandescent lamp is used in combination with the discharge lamp, as shown in FIG. 5, power is supplied to the incandescent lamp after the start period τs in the first embodiment is completed. By doing so, the fluorescent lamp and the incandescent lamp are turned on almost at the same time, and the discomfort does not occur. Here, since the fluorescent lamp is in a slightly discharged state during the starting period τs and is lit with a low luminous flux before the end of the starting period τs, even if the incandescent lamp is lit with the minimum luminous flux during the starting period τs, it is almost the same. There is no sense of discomfort. Other configurations are similar to those of the first embodiment.

[0032]

As described above, according to the present invention, the pulse voltage to the extent that a slight discharge is generated in the discharge lamp is intermittently and repeatedly applied to the discharge lamp before the transition to the lighting state. The discharge voltage will not be turned on reliably with the starting voltage of, but the discharge lamp will be gradually turned on.
Even if the light flux is set to a low light flux at the time of transition to the lighting state, there is an effect that the light flux does not momentarily become a high light flux. That is, even when performing fade-in control or the like, there is an advantage that there is no unnatural effect that the light flux once becomes a high light flux and then becomes a low light flux at the start of lighting, and moreover, the pulse voltage is repeatedly applied. It is possible to gradually shift to the lighting state and surely shift to the lighting state.

If the crest value of the pulse voltage is lowered and the generation interval of the pulse voltage is set to be larger before the transition to the lighting state than before after the transition to the lighting state, the high voltage before the transition to the lighting state. Therefore, there is an advantage that the generation of ions due to the slight discharge is promoted to facilitate the transition to the lighting state, and unnecessary pulse voltage can be reduced in the lighting state to suppress flicker.

Further, when the incandescent lamp is used together with the discharge lamp, if the electric power is supplied to the incandescent lamp from the time when the incandescent lamp is switched to the lighting state, the incandescent lamp lights up prior to the discharge lamp, which causes a feeling of strangeness. There is an advantage that can be prevented.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment.

FIG. 2 is an operation explanatory diagram of the first embodiment.

FIG. 3 is an operation explanatory diagram showing another form of the pulse voltage in the first embodiment.

FIG. 4 is a block diagram of a second embodiment.

FIG. 5 is an operation explanatory diagram of the second embodiment.

FIG. 6 is an operation explanatory diagram of a comparative example with respect to the second embodiment.

FIG. 7 is a block diagram of a main part of a conventional example.

FIG. 8 is an operation explanatory diagram of a conventional example.

[Explanation of symbols]

 1 Lighting Circuit 2 Power Supply Circuit 3 Load Circuit 4 Control Circuit 4a Preheating Control Circuit 4b Dimming Control Circuit 4c Start Control Circuit 4d Maximum Voltage Detection Circuit 5 Fluorescent Lamp Fixture 6 Incandescent Lamp Fixture 7 Dimming Control Device

Claims (4)

[Claims] 1. A discharge lamp lighting control system in which a lighting circuit capable of dimming by adjusting a voltage applied to a discharge lamp having a filament is used, and the filament is preheated after a power is turned on and then transitioned to a lighting state. A pulse voltage that causes a slight discharge to the electric lamp is intermittently and repeatedly applied to the discharge lamp before the transition to the lighting state, and a voltage for dimming to obtain a desired output luminous flux is applied after the pulse voltage is applied multiple times. A discharge lamp lighting control method characterized by being applied to an electric lamp. 2. A pulse voltage or a voltage for dimming, whichever is greater, is applied after the discharge lamp has shifted to the lighting state, and after the discharge lamp has shifted to the lighting state before it shifts to the lighting state. 2. The discharge lamp lighting control system according to claim 1, wherein the crest value of the pulse voltage is set higher and the time interval for generating the pulse voltage is set larger. 3. A starting period in which, after a preheating period for preheating the discharge lamp, a voltage substantially equal to the minimum luminous flux of the discharge lamp during dimming control and a pulse voltage set higher than this voltage are alternately applied to the discharge lamp. The discharge lamp is provided with the higher voltage of the voltage for dimming and the pulse voltage for making the discharge lamp the minimum luminous flux at the end of the starting period and increasing the output luminous flux to the desired output luminous flux with the passage of time. The discharge lamp lighting control method according to claim 1, wherein the discharge lamp lighting control method is applied. 4. An incandescent lamp for illuminating an illumination space by a discharge lamp is added, and the voltage for dimming is applied to the discharge lamp, and at the same time, power supply to the incandescent lamp is started.
Alternatively, the discharge lamp lighting control method according to claim 3.