JPH08264295A - Discharge lamp lighting device and lighting system - Google Patents

Abstract

PURPOSE: To prevent flicker surely at a deep dimming time. CONSTITUTION: A discharge lamp lighting device is equipped with a setting means 5 which sets a dimming level, a high frequency inverter circuit 1 which controls an operation state corresponding to a set dimming level so as to dimming-light a discharge lamp 2, and a ripple adding means 9 which superimposes a ripple component of 10% ripple rate or less on the lamp current of a discharge lamp 2 at a dimming lighting time. The envelope waveform of the lamp current is substantially equivalent to the amplitude modulated envelope waveform by the ripple component of 10% ripple rate or less so as to conduct dimming lighting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dimmable discharge lamp lighting device and a lighting device for lighting a discharge lamp using a high frequency inverter circuit.

[0002]

2. Description of the Related Art Conventionally, some discharge lamp lighting devices are provided with a dimming function in order to enhance their utility value. There are various types of methods for dimming the discharge lamp. For example, a high-frequency inverter circuit is applied to provide a deep dimming function, and the one realized by changing the lighting frequency (operating frequency) of the high-frequency inverter circuit in accordance with the level of the dimming signal. is there. That is, the lighting frequency of the high-frequency inverter circuit becomes higher as the dimming level becomes deeper, and the lighting frequency of the high-frequency inverter circuit becomes lower as the dimming level becomes shallower (closer to the total light). It dims a lamp connected to a ballast. When the dimming level is determined, the lighting frequency is controlled to a certain lighting frequency according to the dimming level.

FIG. 6 is a signal waveform diagram showing the waveform of the lamp current I _L of this system. Figure 6 (a) shows the case of full light,
FIG. 6B shows the time of dimming. Therefore, when the discharge lamp is stably lit at a certain dimming level, both the lamp current waveform and the lamp voltage waveform have a constant amplitude.

[0004]

However, for example, when the dimming lighting is performed at the deep dimming level, the lighting state of the discharge lamp may become unstable and flickering may occur.
This may occur not only during dimming but also under low temperature conditions such as a low ambient temperature of the lamp, and is remarkable when lighting at a deep dimming level under low temperature conditions. Therefore, the lighting state gives an unpleasant feeling.

The cause of flickering under such conditions is not clear, but when considering the equivalent circuit of a discharge lamp, the equivalent resistance between the filament and the conductor film attached to the inner surface of the tube wall is considered. There is a distributed capacitance, and the higher the lighting frequency corresponding to the deep dimming level, the more the leakage current flowing through this distributed capacitance cannot be ignored, and the main discharge path becomes unstable. The same applies to a lamp having no conductor film (for example, FL or FHF) because there is a distributed capacity between the lamp and the tube wall (glass).

Further, during deep dimming or at low temperature, it is presumed that the mercury vapor pressure decreases due to the low temperature of the lamp, which causes unstable light emission. With respect to this point, the present inventors produced fluorescent lamps having a bulb inner diameter of 25.5 mm with various lamp gas pressures in the range of 1.7 to 3.4 Torr. It was performed lighting test while varying a lamp current I _L (mA) at a low temperature of.

FIG. 7 is an explanatory diagram showing the test results.
That is, in FIG. 7A, the hatched area is
This shows that significant flicker occurs, and it can be understood that the above-described trouble occurs in a region where the lamp current I _L is small (in other words, a dimming state).
Furthermore, it was subjected to a lighting test likewise the lamp temperature Ta and the lamp current I _L is variously changed for fluorescent lamps which are 3Torr lamp gas pressure, as shown in FIG. 7 (b), in the low temperature region, Flicker became noticeable.

In order to eliminate such inconvenience, PW
By using the M (pulse width modulation) signal as an external signal for dimming, the dimming frequency state (a large amplitude portion) and the dimming frequency state (a small amplitude portion) are set to P during dimming.
Japanese Patent Application Laid-Open No. 63-245898 discloses a dimming system of two-stage frequency switching in which a desired dimming level is obtained by alternately and periodically switching according to a WM signal. Alternatively, the lamp current I _L in accordance with the PWM signal
There is also a system in which there is a pause section so that a desired dimming level is obtained as a whole.

FIG. 8 is a signal waveform diagram showing such a conventional system, FIG. 8 (b) shows an example of a signal waveform at the time of dimming by the former dimming system of two-stage frequency switching, and FIG. ) Shows a signal waveform of the latter method which has a pause section.

However, in the case of such a dimming system in which the frequency is switched in two stages, during deep dimming, a rest section occurs in the lamp current I _L , the main discharge path is not maintained, and re-ignition is required. After all, a high voltage pulse is needed. Further, since the light ripple is large, it is likely to cause flicker.

Therefore, the present invention does not depend on the deep dimming level, particularly the dimming level under low temperature conditions, and
An object of the present invention is to provide a discharge lamp lighting device that can always be lit stably without causing flicker and an illumination device using the discharge lamp lighting device.

[0012]

According to another aspect of the present invention, there is provided a discharge lamp lighting device, comprising: setting means for setting a dimming level; an operating state of the discharge lamp being controlled according to the set dimming level. A high frequency inverter circuit for dimming and lighting; and a ripple adding means for superimposing a ripple component having a ripple rate of 10% or less on the lamp current of the discharge lamp during dimming and lighting.

In the present invention, the ripple rate means a value given by (b−a) / a (× 100%), where a is a minimum peak value and b is a maximum peak value in the lamp current waveform. . As the high-frequency switching circuit forming the high-frequency inverter circuit, a half-bridge circuit configuration, a full-bridge circuit configuration, a one-stone type, etc. are allowed.

The invention according to claim 2 is the discharge lamp lighting device according to claim 1, wherein the high frequency inverter circuit variably controls the lighting frequency according to the dimming level signal set by the setting means. Turn on the light.

According to a third aspect of the present invention, in the discharge lamp lighting device according to the first or second aspect, the dimming level at which the ripple component is superimposed by the ripple adding means is 20 at full light.
% Or less. For example, it is realized by providing a switching means or the like which is closed only when the dimming level becomes 20% or less at the output portion of the ripple adding means to allow superimposition on the lamp current.

The invention according to claim 4 is the discharge lamp lighting device according to claim 1 or 2, wherein the dimming level at which the ripple component is superimposed by the ripple adding means is not more than an arbitrary level. For example, it is realized by providing the output part of the ripple adding means with a switching means or the like which is closed only when the dimming level becomes lower than an arbitrarily set arbitrary level, and allowing superposition on the lamp current.

The invention according to claim 5 is the invention according to claims 1 to 4.
The discharge lamp lighting device according to any one of claims 1 to 5, further comprising an LC resonance circuit connected between the high frequency inverter circuit and the discharge lamp, and the ripple adding means modulates the oscillation frequency to superimpose the ripple. Add ingredients.

The present invention as defined in claim 6 is any one of claims 1 to 4.
The discharge lamp lighting device according to any one of claims 1 to 5, wherein the ripple adding means generates a ripple generation signal to be superimposed on the dimming level set by the setting means and output to the high frequency inverter circuit. It is composed of

The invention according to claim 7 is the discharge lamp lighting device according to claim 6, wherein the ripple generation signal generated by the ripple generation signal generation circuit is a triangular wave signal. This triangular wave signal is permitted to be generated by integration processing of a rectangular wave signal, for example.

The invention as defined in claim 8 is defined by claim 1 through claim 7.
In the discharge lamp lighting device according to any one of items 1 to 5, when the frequency f of the ripple component to be superimposed on the lamp current is 500 Hz or more, and the ripple rate is 500 Hz to 1 kHz with respect to the frequency f, ripples are generated. The rate is 8 to 10%, the ripple rate is 2 to 5% when f is 1 kHz to 2 kHz, and the ripple rate is 1 to 1 when f is 2 kHz or more.
The relationship of 2.5% is satisfied.

An illumination device according to a ninth aspect of the present invention is the discharge lamp lighting device according to any one of the first to eighth aspects; a discharge lamp that is energized by the discharge lamp lighting device to light; a discharge lamp lighting device. And a device main body on which the discharge lamp is mounted.

[0022]

In the invention of claim 1, since the ripple component is superimposed on the lamp current for the discharge lamp at the time of dimming lighting, the current for the discharge lamp is reduced or the current is increased depending on the level of the lighting frequency. The action to flow is alternately repeated. Therefore, when considering the lamp current waveform, it is substantially equivalent to the envelope waveform of the lamp current amplitude-modulated by the ripple component. In particular, since the ripple rate of the ripple current to be superimposed is 10% or less, the light output can be deeply narrowed without causing flicker, and stable lighting is possible even at deep dimming level, and at the same time,
No humming occurs from the winding portion or the like. After all, the discharge lamp can be lit without causing flicker and flicker because the light ripple is not large even during lighting at the deep dimming level. In addition, basically, the ripple component may be superimposed, and a simple circuit configuration is sufficient.

According to the second aspect of the present invention, the high frequency inverter circuit causes the discharge lamp to perform the dimming lighting by variably controlling the lighting frequency according to the dimming level signal set by the setting means. A ripple component having a ripple rate of 10% or less is superimposed on the lamp current whose frequency is variable in this way.

According to the third aspect of the invention, the ripple component is superimposed when the dimming level is 20% or less of the total light. The actual problem of flicker or the like occurs during deep dimming such that the dimming level becomes 20% or less, which is sufficient to prevent flicker.

In the fourth aspect of the invention, since the ripple component is superimposed when the dimming level is equal to or lower than the arbitrary level, the degree of freedom for flicker prevention during deep dimming is increased.
Thus, setting the dimming level at which the ripple component is superimposed to an arbitrary level also means that low temperature conditions, which is one of the causes of flicker, can be taken into consideration.

In the fifth aspect of the invention, the ripple rate of 10% is superimposed by modulating the oscillation frequency.
The following ripple components are added to the lamp current.

In the sixth aspect of the present invention, the ripple generating signal generated by the ripple generating signal generating circuit is superimposed on the dimming level set by the setting means, so that the ripple component having a ripple rate of 10% or less is obtained. Is added to the lamp current.

According to the seventh aspect of the invention, since the ripple generation signal generated by the ripple generation signal generation circuit is a triangular wave signal, circuit stress is small when a ripple component having a ripple rate of 10% or less is added, In addition, the flicker prevention effect is also improved.

According to the eighth aspect of the invention, basically, the frequency of the ripple component superimposed on the lamp current is 50.
Since it is 0 Hz or higher, the frequency modulation control itself associated with the ripple component is a modulation that is not perceived by humans, and humans do not recognize flicker. Especially, the frequency of the ripple component is 5
At 00 Hz or higher, the ripple rate is regulated to an appropriate value of 10% or less for each frequency band, so that flicker prevention and beat prevention in the winding portion can be reliably achieved during deep dimming.

According to the invention of claim 9, claim 1
Since the discharge lamp lighting device according to any one of 1 to 8 is used, it is possible to perform deep dimming lighting without flicker or beat.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the discharge lamp lighting device of the present invention will be described with reference to FIGS. 1 is a schematic circuit diagram, FIG.
Is a signal waveform diagram of each part showing its operation, FIG. 3 is an explanatory diagram of a test result showing a flicker occurrence situation when the discharge lamp is lit by the configuration of this embodiment, and FIG. 4 shows a relationship between the ripple frequency and the ripple rate. It is a characteristic view to show.

First, in FIG. 1, as a basic configuration, a high frequency inverter circuit 1 is connected to a DC power supply V _DC . As the high frequency inverter circuit 1, for example, a well-known half bridge type in which a pair of switching elements (FET = field effect transistor in the illustrated example) Q ₁ and Q ₂ are connected in series is used. Here, although the discharge lamp 2 is between one ends of the switching element Q ₂ is connected, the switching elements Q ₁ and one end of the discharge lamp 2,
An LC resonance circuit 3 including a capacitive ballast C ₀ and an inductive ballast L ₀ is connected between the connection midpoint of Q ₂ and Q ₂ . Switching element Q of the high frequency inverter circuit 1
_A drive circuit 4 is connected to ₁ and Q ₂ . As a result, the high-frequency AC power generated by the alternating on / off oscillation operation of the switching elements Q ₁ and Q ₂ is supplied to the discharge lamp 2 to maintain lighting.

Here, the discharge lamp lighting device of this embodiment has a dimming function by varying the frequency, and the switching elements Q ₁ and Q in the high frequency inverter circuit 1 according to the dimming level from the setting means 5. the operating frequency of the _second on-off (lighting frequency) is configured so as to variably control.
As the setting means 5, for example, a variable reference power source is used. More specifically, the lamp current I flowing through the discharge lamp 2
Current detection winding 6 for detecting the _L is provided, inputs the current detection winding 6 by the detected lamp current I _L and the setting means 5 from the diode D ₁ and the through dimming levels resistor R ₁ Is provided, and the output of the error amplifier 7 is input to the drive circuit 4 via a VCO (voltage controlled oscillator) 8.

Therefore, as the basic control, the setting means 5
The operating frequency of the high-frequency inverter circuit 1 is controlled to be higher as the dimming level set by is increased, and the operating frequency of the high-frequency inverter circuit 1 is controlled to be lower as the dimming level is shallower. The discharge lamp 2 is turned on with the brightness according to the dimming level (the brightness of the discharge lamp 2 is converted into the lamp current I _L and detected, and an error amplifier is provided so as to match the dimming level as the reference input. 7, the frequency is constantly increased or decreased via the VCO8). Such a dimming control system corresponds to the dimming control system described in FIG.

In the case where only such a dimming control method is used, flicker may occur during deep dimming, so that the ripple adding means 9 is provided in this embodiment. As the ripple adding means 9, for example, a ripple generation signal generation circuit 10 is used. This ripple generating signal generating circuit 10 generates a pulsed signal as shown in FIG. 2 (b) and superimposes it on the dimming level from the setting means 5 via the diode D ₂ , and further with the resistor R ₁ and It is input to the error amplifier 7 via an RC integrating circuit 10 formed by a capacitor C ₁ . Here, the ripple rate of the ripple component that the ripple adding means 9 superimposes on the lamp current is 10% or less, and the ripple frequency is 500 Hz.
It is regulated above.

The operation at the time of dimming lighting according to the configuration of this embodiment will be described. At the time of dimming lighting, the signal of the dimming level as shown in FIG. 2A is given to the point A of the setting means 5. On the other hand, a pulse-shaped signal as shown in FIG. 2B is output from point B of the ripple generation signal generation circuit 10 and is superimposed on the dimming level at point C,
Such a signal at the point C, which becomes a pulse signal in a DC bias state as shown in FIG.
After passing 0, the signal at point D becomes a triangular wave signal as shown in FIG. 2 (d) and is input to the reference terminal of the error amplifier 7. Since the dimming level becomes a signal in which the triangular wave signal is superposed in this way and is given to the error amplifier 7 and the VCO 8, after being processed by the VCO 8 whose oscillation frequency is determined according to the voltage waveform, the actual When the lamp current I _L is shown, as shown in FIG. 2E, a triangular wave signal component is a ripple component and is a signal in a form of being superimposed with variable frequency.

Here, the lamp current I _L shown in FIG.
In the waveform of, the minimum value of the peak value is a and the maximum value is b.
In such a case, the ripple rate defined by (b−a) / a (× 100%) is 10% or less.

As a result, for example, when the dimming level is deep, if the drive control for positively superimposing the ripple component is performed as described above, the amplitude of the waveform of the lamp current I _L is large by the ripple amount. The lighting is maintained by the part, and this is repeated at the frequency of the triangular wave signal, so that the lighting is maintained without flicker. At this time, since it is an increase / decrease due to the ripple component and the optical ripple is small, it does not cause flicker. Of course, since the overall brightness is based on the frequency determined according to the dimming level on which the ripple component is superimposed, the overall brightness depends on the desired dimming level.

Using the discharge lamp lighting device according to this embodiment, a plurality of fluorescent lamps having a lamp gas pressure in the range of 1.7 to 3.4 Torr are used and the lamp temperature Ta is 10 ° C.
When the lighting test was conducted under various low temperature conditions while varying the lamp current I _L , the results shown in FIG. 3A were obtained. That is, in FIG. 3, the areas indicated by dotted dots indicate that some flicker occurs, and in a lamp with a gas pressure of 1.7 Torr, some flicker occurs. It was confirmed that the flicker was significantly improved as compared with the conventional example shown in FIG. 5 (a). further,
The fluorescent lamp of the lamp the gas pressure is 3 Torr, the lamp temperature Ta and the lamp current I _L was subjected to a lighting test while varying, in which a result as shown in FIG. 3 (b) was obtained. That is, in a region where the lamp current I _L is small (in other words, the dimming state), the lamp temperature T
Although a little flickering occurs at a low temperature such as a of 5 ° C., it can be confirmed that the flickering is significantly improved as compared with the conventional example shown in FIG. 5B.

As a more detailed examination, the ripple frequency f (H) of the ripple component superimposed on the lamp current I _L
When an experiment for obtaining an appropriate value for the relationship between z) and the ripple rate (%) was performed, the results shown in FIG. 4 were obtained.

FIG. 4 is a characteristic diagram showing the relationship between the ripple frequency and the ripple rate. Even if the light output in the shaded region does not cause flickering, the deep dimming lighting is satisfactorily performed. Area. That is, when the ripple frequency is in the range of 500 Hz to 1 kHz, the ripple rate of 8 to 10% is appropriate, and the ripple frequency is 1 kHz.
In the case of within the range of 2 kHz, the ripple rate is 2
5% is appropriate, and when the ripple frequency is 2 kHz or more, the ripple rate is 1 to 2.5%.

First, when the ripple rate is set to be larger than 10%, the light output cannot be narrowed sufficiently deep, regardless of the ripple frequency, and the desired deep dimming lighting cannot be achieved. This is because when the ripple rate becomes large, bright lighting occurs in a portion having a large peak value, and FIG.
This is because it is similar to the conventional method described in (c). Further, when the ripple frequency was lower than 500 Hz, flicker was recognized regardless of the ripple rate. This is because frequencies below 500 Hz are a frequency band that can be perceived by the human eye. Further, it has been confirmed by visual observation that flicker cannot be sufficiently suppressed even if the ripple rate of the ripple component superimposed on the lamp current is too small.

Therefore, by setting the relationship between the ripple frequency and the ripple rate as described above, it is possible to satisfactorily light the deep dimming light by squeezing the light output deeply without causing flicker.

FIG. 5 is a schematic perspective view showing an embodiment of the illuminating device of the present invention. In the figure, reference numeral 11 denotes a lighting fixture, in which the discharge lamp 2 is detachably mounted, and a discharge lamp lighting device 12 having a dimming function and having the above-described configuration is mounted.

[0045]

According to the first aspect of the present invention, at the time of dimming lighting, the ripple adding means superimposes a ripple component having a ripple rate of 10% or less on the lamp current to dimming lighting. It is possible to make the envelope waveform equivalent to one in which only the ripple component is amplitude-modulated, and the light output can be deeply narrowed without causing flicker, and stable lighting can be achieved even at deep dimming levels. At the same time, it is possible to prevent the occurrence of beats from the winding portion and the like. This enables deep dimming lighting without any trouble.

According to the invention of claim 2, the effect of the invention of claim 1 can be realized with a simple circuit configuration.

According to the third aspect of the present invention, since the ripple component is superimposed only when the dimming level is 20% or less of the total light, it is possible to secure the flicker prevention which does not hinder the practical level.

According to the fourth aspect of the present invention, since the ripple component is superimposed when the dimming level is equal to or lower than an arbitrary level, it is possible to increase the degree of freedom of flicker prevention during deep dimming and to prevent flicker. The low temperature condition, which is one of the causes, can be taken into consideration.

According to the invention of claim 5, the effects of the invention of claims 1 to 4 can be realized with a simple circuit configuration.

According to the invention of claim 6, the effects of the invention of claims 1 to 4 can be realized with a simple circuit configuration.

According to the seventh aspect of the invention, since the ripple generation signal generated by the ripple generation signal generation circuit is a triangular wave signal, circuit stress is reduced when a ripple component having a ripple rate of 10% or less is added. In addition to the effect, it is possible to further improve the flicker prevention effect.

According to the invention described in claim 8, basically,
The frequency of the ripple component superimposed on the lamp current is 500H.
Since z is set to z or more, the ripple component is superposed in a state that is not perceived by humans, and when the frequency of the ripple component is 500 Hz or more, the ripple rate is 10% or less for each frequency band and is defined as an appropriate value. Therefore, it is possible to surely achieve flicker prevention during deep dimming and beat prevention in the winding portion.

According to the invention described in claim 9, since the discharge lamp is dimmed and turned on by using the discharge lamp lighting device according to any one of claims 1 to 8, deep dimming lighting without flicker or beat is provided. It is possible to provide a lighting device capable of

[Brief description of drawings]

FIG. 1 is a schematic circuit diagram showing an embodiment of a discharge lamp lighting device of the present invention.

FIG. 2 is a signal waveform diagram of each part showing its operation.

FIG. 3 is an explanatory diagram of test results showing a flicker occurrence situation when a discharge lamp is turned on by the configuration of the present embodiment.

FIG. 4 is a characteristic diagram showing the relationship between ripple frequency and ripple rate.

FIG. 5 is a schematic perspective view showing an embodiment of a lighting device of the present invention.

FIG. 6 is a signal waveform diagram showing a conventional method.

FIG. 7 is an explanatory diagram of test results showing a flicker occurrence state when a discharge lamp is turned on by a conventional configuration.

FIG. 8 is a signal waveform diagram showing another conventional method.

[Explanation of symbols]

 1 High Frequency Inverter Circuit 2 Discharge Lamp 3 LC Resonance Circuit 5 Dimming Level Setting Means 9 Ripple Adding Means 10 Ripple Generation Signal Generation Circuit 11 Instrument Main Body 12 Discharge Lamp Lighting Device

Claims (9)

[Claims] 1. A setting means for setting a dimming level; a high-frequency inverter circuit for controlling the operating state according to the set dimming level to lighten the discharge lamp by dimming; a discharge lamp at the time of dimming lighting And a ripple adding means for superimposing a ripple component having a ripple rate of 10% or less on the lamp current; 2. The discharge lamp lighting device according to claim 1, wherein the high-frequency inverter circuit variably controls the lighting frequency according to the dimming level signal set by the setting means to perform dimming lighting. 3. The dimming level at which the ripple component is superimposed by the ripple adding means is 20% or less of the total light;
The discharge lamp lighting device according to claim 1 or 2, characterized in that. 4. The discharge lamp lighting device according to claim 1, wherein the dimming level at which the ripple component is superimposed by the ripple adding means is not more than an arbitrary level. 5. An LC resonance circuit connected between a high frequency inverter circuit and a discharge lamp; and the ripple adding means adds a ripple component for modulating and superimposing an oscillation frequency. Claim 1
5. The discharge lamp lighting device according to any one of 1 to 4. 6. The ripple adding means is a ripple generation signal generation circuit that generates a ripple generation signal that is set by the setting means and is superimposed on the dimming level output to the high frequency inverter circuit. Item 5. The discharge lamp lighting device according to any one of items 1 to 4. 7. The discharge lamp lighting device according to claim 6, wherein the ripple generation signal generated by the ripple generation signal generation circuit is a triangular wave signal. 8. When the frequency f of the ripple component to be superimposed on the lamp current is 500 Hz or more and the ripple rate is f = 500 Hz to 1 kHz with respect to the frequency f, the ripple rate is 8 to 10%, and f is When the frequency is 1 kHz to 2 kHz, the ripple rate is 2 to 5%, and when f is 2 kHz or more, the ripple rate is 1 to
The relationship of 2.5% is satisfied;
The discharge lamp lighting device according to any one of 1. 9. The discharge lamp lighting device according to any one of claims 1 to 8, a discharge lamp which is energized by the discharge lamp lighting device to light, and a discharge lamp lighting device and an instrument body on which the discharge lamp is mounted. And a lighting device.