JPH0757886A - Electrodeless dischage lamp lighting device - Google Patents

Abstract

PURPOSE:To provide a stable light output having no flicker by setting the ON-time of a control signal for lighting an electrodeless discharge lamp longer than the time obtained by adding the time until the discharge lamp is lighted and the time until high frequency power is stabilized after lighting. CONSTITUTION:The ON-time (lighting time for lighting an electrode less discharge lamp 7) of a dimming signal given from a control signal generator 9 to a dimming circuit 6 is set longer than the time obtained by adding the ignition starting time of the discharge lamp 7 and the time until the output of high frequency power is stabilized after lighting. Thus, the fluctuation of the ignition starting time is absorbed, and even in the state where the light output is throttled by time division control, a substantially fixed light output can be provided although it is slightly fluctuated every period. Namely, even when the duty ratio of time division at the flashing or dimming of the discharge lamp is small, the lower limit lighting time can be kept for a required time for lighting or more, the light output having no flicker can be consequently provided, and the dimming-allowable lower limit can be minimized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeless discharge lamp for issuing an electrodeless discharge lamp by applying a high frequency electromagnetic field to an electrodeless discharge lamp in which a discharge gas such as an inert gas or a metal vapor is sealed in a glass bulb. The present invention relates to an electric lamp lighting device.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 14, an electrodeless discharge lamp lighting device of this type for applying a high-frequency electromagnetic field to an electrodeless discharge lamp to issue a direct current power source E and a DC power source E is used. A high-frequency power supply means A that receives power supply and outputs high-frequency power, a high-frequency power supply coil 8 connected between the output terminals of the high-frequency power supply means A, and a high-frequency power supply coil 8 arranged in the vicinity of the high-frequency power supply coil 8. And an electrodeless discharge lamp 7 in which a discharge gas (for example, mercury and rare gas) such as an inert gas or a metal vapor is sealed in a transparent glass bulb or a spherical glass bulb whose inner surface is coated with a phosphor. It is configured.

The high frequency power supply means A is a direct current power source E.
The oscillator circuit 1 connected to both ends of the
High-frequency power that is connected and amplified by receiving the signal from the oscillator circuit 1.
Amplification circuits 2 and 5 that output force, electrodeless discharge lamp 7 and amplification
From the matching circuit 4 provided between the circuits 2 and 5
It is configured. The amplification circuit 2 outputs the oscillation output of the oscillation circuit 1.
It is a preamplifier that amplifies, and the amplifier circuit 5 is
Configure a main amplifier that further amplifies the output with high frequency power
The amplifier circuit 2 that constitutes the preamplifier is shown in FIG.
Capacitor C₆, C ₁₆, Resistance R₃, R₈~
R_Ten, Coil L_FiveAnd transistor Q_FourTo Class C amplification times
Make a road. The coil L_Five, Capacitor C₁₇Departed by
I try to tune to the vibration frequency. And Main Anne
The amplifier circuit 5 constituting the
Abbreviated as FET) Q_Five, Capacitor C_Five, C₁₇,resistance
R₁₂, Coil L_Four, L₇Consists of. Coil L₇Is FET
Q_FiveIt is included to cancel the input capacitance of
Resistance R₁₂Is FETQ_FiveInput impedance of the amplifier circuit
It is included to match the 2 output.

The filter circuit 3 is composed of a coil L ₃ and a capacitor C _4, and prevents high frequency waves from returning to the power supply. The matching circuit 4 is composed of capacitors C _{18 to} C _20, etc., and is provided between the output of the amplifier circuit 5 and the electrodeless discharge lamp 7 and the high-frequency power supply coil 8 in the subsequent stage to match the impedances of both. The impedance matching is performed so that high frequency power is efficiently transmitted to the electrodeless discharge lamp 7 by eliminating reflection.

The electrodeless discharge lamp 7 is inert in the glass bulb.
Gas, discharge gas such as metal vapor is filled.
In the vicinity of this outer circumference, a high-frequency electric field which is an air-core coil with several turns
The power supply coil 8 is wound to discharge high frequency power without electrode
The discharge gas in the lamp 7 is supplied. Dimming as a control means
Circuit 6 is FETQ₃And the discharge resistance connected to the gate
R ₁₄Consists of F ETQ₃The drain of the amplifier circuit 2
Transistor Q_FourThe source is connected to the ground
Has been continued. And FETQ₃Control signal to the gate of
A control signal is input from the generator 9.

The operating state will be briefly described below. Now, when the power switch SW is turned on and the power supply from the DC power source E is received, the oscillation circuit 1 starts to oscillate, the signal of the oscillation circuit 1 is transmitted to and amplified by the amplification circuit 2, and then amplified by the amplification circuit 5. The generated signal is transmitted and further amplified. The high-frequency voltage amplified by the amplifier circuit 5 is applied to the high-frequency power supply coil 8 that is arranged in proximity along the spherical outer circumference of the electrodeless discharge lamp 7. Then, the high frequency power supply coil 8
A high-frequency current of several MHz to several hundred MHz is applied to the coil to generate a high-frequency electromagnetic field in the high-frequency power supply coil 8, supply high-frequency power to the electrodeless discharge lamp 7, and generate high-frequency plasma current in the electrodeless discharge lamp 7. To generate ultraviolet rays or visible light.

Next, the case where the control signal is input to the dimming circuit 6 from the control signal generator 9 will be described. When the control signal of the first "L" is input, it becomes similar to the case described above, between the drain and source of the FETs Q ₃ becomes an open state, the output from the oscillation circuit 1 to the base of the transistor Q ₄ is The electrodeless discharge lamp 7 lights up normally.

[0008] When the next control signal "H" is inputted, the sufficiently high voltage is applied to the gate of the FETs Q _3, between the drain and source of the FETs Q ₃ is turned on, so that the transistor Q ₄ , The base voltage becomes 0, the amplification is not performed in the amplifier circuit 2, and the electrodeless discharge lamp 7 is turned off. Where the resistor R ₈
Through R ₁₁ are provided to reduce the influence of load fluctuation.

In this way, the control signal "H" level, "
By appropriately setting the ratio of the L "level signal, the electrodeless discharge lamp 7 is set higher than the blinking frequency at which human visual perception can be confirmed.
That is, an arbitrary dimming characteristic can be obtained by the time-division control in which the light is turned on at a repetition cycle that does not give a flicker to the eyes. If the blinking cycle is set to about 100 Hz or more, so-called duty dimming becomes possible.

The reason why the time division control is used as the dimming method is that the blinking response of the electrodeless discharge lamp lighting device is excellent. However, even if the blinking response is excellent, it does not mean that there is no time until the start-up lighting (a time of about 0.1 to 0.4 [ms] is required). FIG.
The lighting state of the electrodeless discharge lamp lighting device during dimming is shown in FIG.

FIG. 1A shows a control signal, and FIG. 1B shows a high frequency power supply coil 8 while the electrodeless discharge lamp 7 is dimming and lighting.
(C) is the input current of the high frequency power supply means A from the DC power supply E. At time t ₁ , when the control signal becomes “L”, the FET Q ₃ is turned off, the high frequency power is supplied to the high frequency power supply coil 8, and after a period t ₁ −t ₂ (T ₁ ) until the start and lighting. Electrodeless discharge lamp 7
Lights up. And the control signal ON period (“L” period)
(The shorter the t ₁ -t ₃ (Ta) in FIG. 16, the higher the dimming level and the smaller the light output.

FIG. 17 shows the waveform of the DC input current to the high frequency power supply means A and the waveform of the optical output of the electrodeless discharge lamp 7 at the time of starting and lighting. As shown in FIG. 17A, a large current flows into the DC input current to the high frequency power supply means A when the electrodeless discharge lamp 7 is not lit, and at the same time as the lighting, the current oscillates to a constant current and stabilizes. The light output at that time is as shown in FIG. The ignition starting period T ₁ until the electrodeless discharge lamp 7 is started and lit depends on the temperature characteristics of each element constituting the high frequency power supply means A and the ease and state of starting the electrodeless discharge lamp 7 at that time. There is a fluctuation of. T _{2 in} FIG. 17B shows a period after the electrodeless discharge lamp 7 is turned on until the output of the high frequency power supply means A becomes stable.

[0013]

[Problems to be Solved by the Invention]
As shown in (a), if the control signal is adjusted so that the lighting time (control signal ON period) is infinitely short, the ignition starting period T ₁ until the electrodeless discharge lamp 7 reaches the starting lighting is slightly different. 18B and 18C, the lighting mode shown by the solid line and the lighting mode shown by the broken line appear in the input current and the light output shown in FIGS.

Therefore, in the case of dimming or blinking by time division control as described above, when the time division ratio is approached to the lower limit value, the solid line lighting mode and the broken line lighting in FIG. Since the mode appears, as a result, it looks like flicker, and there is a problem that dimming has a limit. Here when there is no electrodeless discharge lamp 7 (no load condition)
In FIG. 16, the voltage across the high frequency power supply coil 8 is set to the unloaded secondary voltage, the input current flowing in the lighting circuit in the unloaded state, the thermal stress (loss) of the FET Q ₅ and the ON period of the dimming signal shown in FIG. Ta / one cycle Tb (t
Fig. 1 shows the correlation with ₁ -t ₄ ) [dimming duty ratio]
9 shows. The Ta / Tb curve in FIG. 19 indicates the limit value at which dimming is possible. That is, it shows that flicker occurs when Ta / Tb becomes smaller than this.

In FIG. 19, the unloaded secondary voltage is high.
The smaller the dimming duty ratio Ta / Tb that can be dimmed,
In this case, the light output can be narrowed down. On the contrary, no load
The higher the secondary voltage is set, the more unloaded FETQ_FiveLoss of
There is a drawback that the loss is large. Also, the high frequency power supply means A
The main amplifier used for the amplifier circuit 5 is shown in Fig. 20.
Also proposed a conventional example that uses a class E amplifier circuit to improve efficiency.
Is being proposed. This class E amplifier is connected in series with the DC power supply E.
FETQ connected_FiveAnd input current from the DC power supply E
RF choke L for constant_FiveAnd FETQ_FiveParallel to
Connected capacitor C_{twenty one}And a resonance point near the operating frequency
Resonance coil L₆, Resonance capacitor C_{twenty two}In series
FET composed of a circuit and performing an ideal class E operation
Q_FiveVoltage V across_DS, FETQ_FiveCurrent I flowing through_DWaveform
Is as shown in FIG. The characteristic of class E operation is FETQ
_FiveVoltage V across_DS, And the slope becomes 0 and at the same time the current I
_DFETQ_FiveWhen turns from off to on
The switching loss of is almost zero. But RF
Chalk L_FiveHas a high frequency to keep the input current approximately constant
Large enough impedance at (more than operating frequency)
It is designed to have an electrodeless discharge lamp 7
When lighting, the input current becomes as shown in Fig. 22,
Starting period T₁Will be several hundreds μs to several ms. this
This is the case when the electrodeless discharge lamp 7 is dimmed by time division control.
The lower limit of the dimming level in case of
Leads to. FIG. 23A shows a frequency of 125 Hz (T
b = 8 ms) High frequency output from the high frequency output coil 8
Frequency voltage, and the input current at this time is shown in FIG.
As shown in (b). Reduce the ON period of this control signal
Figure 2 shows the input current when the dimming is set to the lower limit.
As shown in 3 (c), as described above, the ignition start period
Interval T₁That the lower limit of dimming is limited
become. In the illustrated example, the dimming duty ratio Ta / Tb is 1 ms.
At / 8 ms, 12.5% is the lower limit of dimming.

In FIG. 20, the amplification circuit 2, which is a preamplifier, the dimming circuit 6, and the control signal generator 10 are omitted for simplification of description. The present invention has been made in view of the above problems, and an object of the inventions of claims 1 to 5 is that no flicker occurs when dimming is restricted to the lower limit direction, and electrodeless discharge is performed. It is an object of the present invention to provide an electrodeless discharge lamp lighting device capable of reducing the lower limit value for dimming an electric lamp.

It is an object of the invention of claim 6 to provide an electrodeless discharge lamp lighting device in which the lower limit of dimming can be made small and the loss of the amplifying element of the high frequency power supply means is made small. To provide. It is an object of the inventions of claims 7 to 15 to provide an electrodeless discharge lamp lighting device capable of shortening the ignition starting period and decreasing the dimmable lower limit value.

[0018]

In order to achieve the above-mentioned object, according to the invention of claim 1, a power source, a high frequency power supply means for receiving a power supply from the power source and outputting a high frequency power, and the high frequency power supply means. A high frequency power supply coil connected between the output terminals of the power supply means, and a discharge gas such as an inert gas or a metal vapor is enclosed in a glass bulb, and the electrode is placed close to the high frequency power supply coil and lights up. In an electrodeless discharge lamp lighting device provided with a discharge lamp and a control means for controlling the output of the high-frequency power supply means by blinking or time division dimming according to a control signal, when performing blinking or time division dimming, there is no The ON time of the control signal for lighting the electrode discharge lamp is set to be longer than the required lighting time, which is the sum of the time until the electrodeless discharge lamp lights up and the time until the output of the high-frequency power supply means becomes stable after lighting. Also It is.

A second aspect of the present invention is an embodiment of the first aspect of the invention, and further comprises means for turning off the control signal when the ON time of the control signal is shorter than the required lighting time. Claim 3 is an embodiment of the invention of claim 1,
When the ON time of the control signal is shorter than the required lighting time, a means for keeping the ON time of the control signal equal to or longer than the required lighting time is provided.

A fourth aspect of the present invention is an embodiment of the first aspect of the invention, wherein when the ON time of the control signal is shorter than the required lighting time, the ON time of the control signal is kept equal to or longer than the required lighting time, It is equipped with a means to extend only the off time. A fifth aspect of the present invention is an embodiment of the first aspect of the invention, in which the frequency of the control signal for performing the time division dimming is higher than the blinking frequency at which human visual perception can be confirmed and the lighting duration is 100. It is set to be smaller than the frequency when the value obtained by dividing the lower limit dimming ratio by the value multiplied by is the frequency.

According to a sixth aspect of the invention, a power source, a high frequency power supply means for receiving high frequency power from the power source and outputting high frequency power, and a high frequency power supply connected between output terminals of the high frequency power supply means. The coil, an electrodeless discharge lamp that encloses a discharge gas such as an inert gas or a metal vapor in a glass bulb, and is placed close to the high frequency power supply coil to light, and the output of the high frequency power supply means according to a control signal. In a device for lighting an electrodeless discharge lamp, the voltage applied to the coil for high frequency power supply is changed to a coil for high frequency power supply as the output by dimming becomes smaller. The output voltage control means is provided for changing the voltage applied to the high frequency power supply coil so that the applied voltage becomes large.

According to a seventh aspect of the present invention, a power source, a high frequency power supply means for receiving a power supply from the power source and outputting a high frequency power, and a high frequency power supply means connected between the output terminals of the high frequency power supply means. The coil, an electrodeless discharge lamp that encloses a discharge gas such as an inert gas or a metal vapor in a glass bulb, and is placed close to the high frequency power supply coil to light, and the output of the high frequency power supply means according to a control signal. In the electrodeless discharge lamp lighting device provided with a control means for blinking or time-dimming dimming control, the input current of the high frequency power supply means during the ignition starting period immediately after the power is turned on until the electrodeless discharge lamp is lit. It is provided with a means for increasing and maintaining lighting by an efficient amplifying means after lighting.

The invention of claim 8 is an embodiment of the invention of claim 7, wherein the amplifying means is composed of a class E amplifier circuit. The invention of claim 9 is an embodiment of the invention of claim 7 or 8, wherein at least one constant of the constituent elements of the amplifying means is changed during the ignition starting period. The invention of claim 10 is an embodiment of the invention of claim 7, 8 or 9, wherein the RF provided in the amplifying means during the ignition starting period.
It changes the constants of the choke and the capacitor connected in parallel to the amplification element.

The invention of claim 11 is an embodiment of the invention of claim 7, 8 or 9, wherein during the ignition starting period, the RF choke provided in the amplification means and the constant of the resonance capacitor are set. It changes. The invention of claim 12 is
According to an embodiment of the invention of claim 7 or 8 or 9, the constants of the resonance choke and the RF choke provided in the amplifying means are changed during the ignition starting period.

The invention of claim 13 is an embodiment of the invention of claim 7 or 8 or 9 or 10 or 11 or 12, wherein the impedance of the RF choke provided in the amplifying means during the ignition starting period. Is changed in the direction of decreasing. The invention of claim 14 is the invention of claim 7 or 8.
Alternatively, it is an embodiment of the invention of 9 wherein the amplifying means which operates in class C is operated during the ignition starting period.

The invention of claim 15 is an embodiment of the invention of claim 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14, wherein the ignition starting period is 400 μs or less.

[0027]

According to the inventions of claims 1 to 5, even if the duty ratio of the time division when blinking or dimming the electrodeless discharge lamp by the time division control is small, the lower lighting time is required to be turned on. It is possible to keep the time or more, and as a result, it is possible to perform control so that a stable light output that does not cause flicker can be obtained.

According to the sixth aspect of the present invention, the voltage applied to the high frequency power supply coil is set so that the voltage applied to the high frequency power supply coil increases as the output by dimming decreases. Since the output voltage control means for changing the voltage applied to the working coil is provided, the lower limit value of dimming can be reduced, and the loss of the element of the amplification means of the high frequency power supply means can be reduced.

According to the invention of claims 7 to 15, the input current of the high-frequency power supply means is increased during the ignition starting period immediately after the power is turned on until the electrodeless discharge lamp is lit, and the amplifying means is efficient after lighting. Since the means for maintaining lighting is provided, the ignition starting period can be shortened.

[0030]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) This embodiment is an embodiment corresponding to the invention of claim 1, and since the circuit of the embodiment basically uses the same circuit as that of FIG. 14 and FIG. For the numbers and symbols of the components that are omitted and used in the following description, refer to FIGS.

Thus, in this embodiment, the ON time Ta of the dimming signal given from the control signal generator 9 to the dimming circuit 6 (the lighting time for lighting the electrodeless discharge lamp 7) is the electrodeless discharge in FIG. Time until the light 7 is turned on (ignition start period T ₁ )
Then, the time T ₂ (actually 0.1 time from the lighting of the electrodeless discharge lamp 7 until the output of the high frequency power supply means A becomes stable)
ms to 5 ms) (hereinafter, lighting required time T
It is set to be longer than (referred to as ₀ ). Therefore, FIG.
Minimum lighting time shown in (a) (ON time Ta of dimming signal)
By setting the above lighting required time T ₀ , the fluctuation of the ignition start period T ₁ is absorbed, and the DC input current waveform is shown in FIG. 1B even when the light output is narrowed down by the time division control. As a result, a substantially constant light output is obtained as shown in FIG. 1 (c), although there are some fluctuations in each cycle, and an electrodeless discharge lamp lighting device without flicker is obtained.

That is, when the dimming is performed by the time division control, the lower limit of the duty of the control signal is determined by the required lighting time T ₀ as shown in FIG. (Embodiment 2) In the present embodiment, when the dimming is performed by the time division control, the duty (hereinafter referred to as the lower limit duty) in which the ON time Ta of the control signal of the control signal generator 9 is equal to the lighting required time T ₀ is used. I dealt with when it gets smaller,
As shown in FIG. 3, a control signal converter 10 is inserted between the control signal generator 9 and the dimming circuit 6 of the electrodeless discharge lamp lighting device. The control signal converter 10 includes a control signal generator 9
When the ON time Ta of the control signal is smaller than the duty (hereinafter referred to as lower limit duty X) that is equal to the required lighting time T ₀ , the duty is converted as indicated by a broken line a in FIG. Is prevented from being shorter than the required lighting time T ₀ . The broken line b in FIG. 4 indicates that the output of the control signal converter 2 becomes 0 when a control signal below the lower limit duty X is input from the control signal generator 9. In other words, it shows a case of performing a movement to turn off the light.

[0033] When (Example 3) gradually reduces the duty of the control signal when dividing dimming time the electrodeless discharge lamp lighting device, wherein corresponding to the lighting duration T ₀ as shown in FIG. 5 (a) Reach lower limit duty X. In this embodiment, when the dimming is narrowed down to the lower limit duty X or less, the control signal converter 2 is provided which works so as to lengthen only the off time of the control signal as shown in FIG. 5B. By the function, it is possible to perform light control below the lower limit duty X. The configuration of this embodiment is similar to that of the second embodiment.

By the way, when the electrodeless discharge lamp lighting device is time-division controlled, the lower limit of the frequency of the time-division is the flicker frequency that human visual perception can be confirmed (various ambient conditions.
It depends on the light source). Further, the upper limit is restricted by the relationship between the desired lower limit dimming ratio and the lighting required time T ₀ . Therefore, the blinking frequency (frequency of the time-division control signal) is set higher than the flicker frequency at which human visual perception can be confirmed, and [desired lower limit dimming ratio (%) / (required lighting time T ₀ × 100 (%)] )] An electrodeless discharge lamp lighting device without flicker can be realized by setting the frequency lower than Hz.

(Embodiment 4) This embodiment reduces the light output.
So that the coil voltage at no load can be increased
In order to prevent loss in case of
The control circuit 11 and the switch circuit 12 are added to the circuit of FIG.
It has been added. Here, the output voltage control circuit 10 is
Comparator IC₁And a resistor R for dividing the power supply voltage Vcc
₂₀And resistance R_{twenty one}Series circuit with and a resistor that divides the control signal
R_{twenty three}And resistance R_{twenty two}, And a series circuit for smoothing the control signal.
Indexer C_{twenty three}And comparator IC ₁And the comparator
IC₁Output by the resistor R_{twenty three}Tran driven through
Dista Q₆And this transistor Q₆Primary winding through
Transformer Tr to which power supply voltage Vcc is applied₁Composed of and
To be done. Further, the switch circuit 12 is a controller of the matching circuit 4.
Densa C₁₉In parallel with capacitor C₁₉Through '
Star Q₇Are connected in parallel.
Q₇The above-mentioned transformer Tr is connected between the base and emitter of₁Of 2
Resistance R in the next winding_{twenty four}Connected via. A transistor
Q₇The diode connected in parallel with is not necessary.

Next, the operation of this embodiment will be described with reference to FIGS.
explain. First, FIG. 7 shows the case where all the electrodeless discharge lamps 7 are turned on.
FIG. 8 is a waveform diagram of each part when the dimming of the electrodeless discharge lamp 7 is performed.
FIG. 7 is a waveform chart of each part when turned on, and is shown in FIG.
When the control signal for dimming is "L", FE
TQ₃Is turned off, and high frequency without rest period shown in Fig. 7 (b)
A wave voltage is applied to the high frequency power supply coil 8. this
Input power from the DC power supply E to the high frequency power supply means A
The flow is as shown in FIG. 7 (c). In addition, the control signal is
Since it is L ″, the comparator I of the output voltage control circuit 11
C₁The non-inverting terminal of is zero. Therefore, the comparator I
C₁The output terminal of is also zero, and the transistor Q₆Turns off
It Therefore transformer Tr₁Secondary output does not occur,
The switch circuit 12 is turned off and the matching circuit 4 is
SA C₁₈~ C ₂₀Composed of only.

On the other hand, when a dimming control signal is input to the dimming circuit 6 as shown in FIG. 8A, the FET Q ₃ is turned on and off, and the intermittent high frequency voltage shown in FIG. 8B is high frequency power. The electrodeless discharge lamp 7 is dimmed by being applied to the supply coil 8. The input current from the DC power supply E to the high frequency power supply means A at this time is as shown in FIG. When a predetermined voltage according to the on-duty of the control signal is applied to the non-inverting input terminal of the comparator IC ₁ of the output voltage control circuit 11 and the voltage of the non-inverting input terminal becomes higher than the reference voltage Vref applied to the inverting input terminal. , and "H" output, turning on the transistor Q _6. This turns on the transformer T
A secondary output is generated at r ₁ , the transistor Q ₇ of the switch circuit 12 is also turned on, and this turning on causes the capacitor C ₁₉ to be connected in parallel with the capacitor C ₁₉ ′. That is, the impedance of the matching circuit 4 decreases (Q of the matching circuit 4 increases), and the voltage V ₀₂ across the high-frequency power supply coil 8 when no load is applied and the electrodeless discharge lamp 7 is not connected increases. Here, as shown in FIG. 8D, the high-frequency power during dimming lighting is higher than the voltage V ₀₁ across the high-frequency power supply coil 8 when there is no load at the time of full lighting as shown in FIG. 7D. The voltage V ₀₂ across the supply coil 8 is high.

Therefore, when dimming, by increasing the no-load secondary voltage, the dimming duty ratio Ta / Tb can be reduced as shown in FIG. 19, and as a result, the light output can be narrowed. On the other hand, when the unloaded secondary voltage is increased, the loss of the FET Q ₅ increases, but when dimming,
Since it operates intermittently as shown in (d), FETQ ₅
The loss of is small on average. The point of focus of this embodiment is here, and in the case of intermittently changing the oscillation cycle to perform dimming,
Since the oscillation is intermittent even when there is no load, the thermal stress of the FET Q ₅ , that is, the average loss is small even if the secondary voltage is increased.

When the dimming duty ratio Ta / Tb (or the dimming level) becomes a predetermined level or less, the impedance of the matching circuit 4 is switched by the switch circuit 12, but the setting of the above level is easy by the design of the output voltage control circuit 11. become. (Embodiment 5) This embodiment is different from Embodiment _{4 in} that a series circuit of a switch circuit 12 controlled by an output voltage control circuit 11 and an inductance L ₄ 'is connected in parallel to the inductance L ₄ as shown in FIG. Be different.

Thus, the dimming duty ratio T of the dimming control signal
If smaller than the predetermined value a / Tb, transistors Q ₇ of the switch circuit 12 output changes to "H" of the output voltage control circuit 11 as described above is turned on. When the transistor Q ₇ is turned on, the inductances L ₄ and L ₄ ′ are connected in parallel, so that the impedance thereof is lowered (or the Q of the amplifier circuit 5 is lowered, so that the electrodeless discharge lamp 7 is not connected and there is no load). The voltage across the high-frequency power supply coil 8 becomes high, that is, the same effect as the circuit of Fig. 6 can be obtained.

In the fourth and fifth embodiments, when the dimming duty ratio Ta / Tb becomes smaller than a predetermined value, the switch circuit 12 intermittently changes the inductance value or the capacitance of the capacitor. Ratio Ta /
Alternatively, the transistor Q ₇ of the switch circuit 12 may be operated in the active region by Tb and the impedance may be continuously changed in accordance with the dimming duty ratio Ta / Tb to continuously change the unloaded secondary voltage.

In the fourth and fifth embodiments, the impedance of the amplifier circuit 5 is
Although it was configured to switch the impedance, the F of the amplifier circuit 5
ETQ_FiveIt may be configured to switch the drive voltage of
Yes. FETQ_FiveIf the drive voltage of the
Pressure increases and drive voltage decreases, the output voltage increases.
The pressure becomes smaller. (Embodiment 6) In this embodiment, as shown in FIG.
Operational amplifier IC provided in the control circuit 11 ₁’
Outputs an amplified signal in proportion to the on-duty of the control signal
So that this operational amplifier IC₁’Amplifies the output
Transistor Q on path 5_Five'Is connected in series to the base
Transistor Q of switch circuit 12 '₇To the base of
I am trying to get it. In other words, the on-duty of the dimming signal
The larger (the more dimmed) the operational amplifier IC₁’Output power
The pressure increases. Therefore, the switch circuit 12 '
Dista Q₇The base current of the transistor increases
Q_FiveThe collector-emitter resistance of is small. others
Therefore, the signal from the amplifier circuit 2 is sufficient for the transistor Q._Five'of
It is supplied to the base and transistor Q_Five’Base dry
As a result, the high frequency power supply coil 8
The voltage at both ends becomes high. That is, the same effect as the circuit of FIG.
You can get it.

(Embodiment 7) The problem when the class E amplifier circuit is used for the amplifier circuit 5 is as described above,
In this embodiment, the problem when this class E amplifier circuit is used for the amplifier circuit 5 is solved, and the structure of the amplifier circuit ₅ is arranged in parallel with the RF choke L ₅ as shown in FIG. 'connected to the series circuit of the switching element S _1, a capacitor C ₂₁ to the capacitor C ₂₁ connected in parallel to the FETs Q _5' 2 of the RF choke coil L ₅ and switching element S
_It differs from the circuit of FIG. 20 in that the _two series circuits are connected in parallel. Incidentally, as in the case of FIG. HH, the dimming circuit 6, the control signal generator 9, and the amplifier circuit 2 constituting the preamplifier are omitted for simplification of description, but it goes without saying that these circuits are provided.

Thus, in this embodiment, the switching element S ₁ is turned on at the time of starting. Therefore, the constant of the entire RF choke becomes smaller than that of the case of L ₅ alone, and as a result, the impedance becomes smaller and the rise time of the input current becomes shorter, so that the ignition starting period T ₁ also becomes shorter. However, reducing the value of the RF choke, ripple increases the input current, the current I _D of the FETs Q _5, the waveform of the voltage V _DS as shown in FIG. 12. Spike current of the current I _D in the figure excessive stress added to the FETs Q _5, the heat generation of the FETs Q _5, leading to destruction. Therefore, if the switching element S _{1 and the} switching element S ₂ are turned on at the same time, the current I
The waveform of _D is corrected as shown in FIG. 21, and excessive stress is not applied to FET Q ₅ .

Next, when the electrodeless discharge lamp 7 is turned on, the switching elements S ₁ and S ₂ are turned off to restore the circuit constant to the original value and the turned-on state is efficiently maintained as the class E amplifier circuit.
In this embodiment, two RF chokes, L ₅ and L ₅ ′, are provided, and the plates are switched by switching elements S ₁ and S _2; however, the impedance of the RF choke is not limited to this. It suffices if the means is small and large after lighting.

Further, the means for correcting the current I _D of the FET Q ₅ is not limited to the capacitor C ₂₁ ′, but the inductance L ₆ ,
The constant of the capacitor C ₂₂ may be changed. If configured as in the present embodiment, during the ignition starting period T ₁ and after starting lighting,
The ignition starting period T ₁ can be shortened by changing the constant of the class E amplifier circuit. (Example 8) This example, parallel to provide a C-class amplification circuit 5 'to the amplification circuit 5 consisting of E-class amplifier circuit as shown in FIG. 13, the amplifier circuit 5 of each the switching elements S _3, S ₄ , 5 ′ is different from the conventional example of FIG.

In this embodiment, the switching element S is activated at the time of starting.
₃ and S ₄ are switched to the class C amplifier circuit 5 ′ side. That is C
Since the class amplifier circuit 5'has no element with a large impedance such as an RF choke, an input current sufficient to turn on the electrodeless discharge lamp 7 immediately after the power is turned on,
Therefore, the ignition starting period T ₁ can be made very short. Next, when the electrodeless discharge lamp 7 is turned on, the switching elements S ₁ and S ₂ are switched to the class E amplifier circuit 5 side to efficiently maintain the turned-on state.

The theoretical efficiency of the C-class and E-class amplifier circuits is 100% at the maximum, but in practical use, the C-class is 80% and the E-class is 90%.
It is a degree. Therefore, maintaining the lighting is more efficient in the E class than in the C class. Here, the amplifying FETs of the amplifier circuits 5 and 5'may be shared, and the circuit constants may be switched for each element.

Although a DC power source is used as the power source E in each of the first to eighth embodiments, a DC power source may be obtained from a chopper circuit for the AC power source, and the DC power source may be used. Needless to say, it is desirable to set the ignition starting period T ₁ to 400 μs (0.4 ms) or less in terms of responsiveness.

[0050]

According to the inventions of claims 1 to 5,
Even if the duty ratio of the time division when blinking or dimming the electrodeless discharge lamp is small by the time division control, the lower limit lighting time can be kept longer than the required lighting time, and as a result, flicker does not occur stably. The light output can be controlled so that the lower limit of dimming can be further reduced.

According to the sixth aspect of the present invention, the voltage applied to the high frequency power supply coil is set so that the voltage applied to the high frequency power supply coil increases as the output by dimming decreases. Since the output voltage control means for changing the voltage applied to the coil for use is provided, the dimmable lower limit value can be made smaller, and the loss of the element of the amplification means of the high frequency power supply means can be made smaller. There is an effect.

According to the invention of claims 7 to 15, the input current of the high frequency power supply means is increased during the ignition starting period immediately after the power is turned on until the electrodeless discharge lamp is lit, and the amplifying means is efficient after lighting. Since the means for maintaining lighting is provided, the ignition starting period can be shortened, and therefore, the dimmable lower limit value can be further reduced.

[Brief description of drawings]

FIG. 1 is a waveform diagram for explaining an operation according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the relationship between the duty of the control signal and the optical output of the above.

FIG. 3 is a block diagram of a main part of a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of a relationship of duty conversion of the control signal of the above.

FIG. 5 is a waveform diagram for explaining the operation of the third embodiment of the present invention.

FIG. 6 is a circuit diagram of a fourth embodiment of the present invention.

[Fig. 7] Fig. 7 is a waveform diagram of each part when all lights are on.

FIG. 8 is a waveform diagram of each part when the dimming lighting is the same as above.

FIG. 9 is a circuit diagram of a fifth embodiment of the present invention.

FIG. 10 is a circuit diagram of a sixth embodiment of the present invention.

FIG. 11 is a circuit diagram in which a part of the seventh embodiment of the present invention is omitted.

FIG. 12 is a waveform diagram of voltage and current of FET Q ₅ of the amplifier circuit 5 of the above.

FIG. 13 is a circuit diagram in which a part of the eighth embodiment of the present invention is omitted.

FIG. 14 is a circuit block diagram of a conventional example.

FIG. 15 is a circuit diagram of the above.

FIG. 16 is a waveform diagram for explaining the operation of the above.

FIG. 17 is a waveform diagram for explaining the operation of the above.

FIG. 18 is a waveform diagram for explaining the operation of the above.

FIG. 19 is a diagram for explaining the relationship between the unloaded secondary voltage and the dimming duty ratio in the same as above.

FIG. 20 is a partially omitted circuit diagram of another conventional example.

FIG. 21 is a waveform diagram of voltage and current of FET Q ₅ of the amplifier circuit 5 of the above.

FIG. 22 is a waveform diagram of the input current of the above.

FIG. 23 is a waveform chart of each part of the above.

[Explanation of symbols]

T ₀ lighting required time

Claims (15)

[Claims] 1. A power supply and a power supply from this power supply,
A high-frequency power supply means for outputting high-frequency power, a high-frequency power supply coil connected between the output terminals of the high-frequency power supply means, and a glass bulb filled with a discharge gas such as an inert gas or a metal vapor, An electrodeless discharge lamp lighting device provided with an electrodeless discharge lamp which is arranged in proximity to a power supply coil and is turned on, and a control means for blinking or time-divisionally controlling the output of a high-frequency power supply means in accordance with a control signal. In the case of performing blinking or time division dimming, the ON time of the control signal for lighting the electrodeless discharge lamp is the time until the electrodeless discharge lamp is lit and the output of the high frequency power supply means becomes stable after lighting. And an electrodeless discharge lamp lighting device, wherein the lighting time is set longer than the required lighting time. 2. The electrodeless discharge lamp lighting device according to claim 1, further comprising means for turning off the control signal when the ON time of the control signal becomes shorter than the required lighting time. 3. The electrodeless discharge lamp according to claim 1, further comprising means for maintaining the ON time of the control signal at the lighting required time or more when the ON time of the control signal becomes shorter than the lighting required time. Lighting device. 4. When the ON time of the control signal becomes shorter than the lighting required time, a means for keeping the ON time of the control signal equal to or longer than the lighting required time and increasing only the OFF time is provided. Lighting of the electrodeless discharge lamp according to claim 1. 5. The lower limit dimming ratio is obtained by dividing the lower limit dimming ratio by the value of the frequency of a control signal for time division dimming that is higher than the blinking frequency at which human visual perception can be confirmed, and the required lighting time multiplied by 100. The electrodeless discharge lamp lighting device according to claim 1, wherein the value is set to be smaller than the frequency when the value is set as the frequency. 6. A power supply and a power supply from this power supply,
A high-frequency power supply means for outputting high-frequency power, a high-frequency power supply coil connected between the output terminals of the high-frequency power supply means, and a glass bulb filled with a discharge gas such as an inert gas or a metal vapor, An electrodeless discharge lamp lighting device provided with an electrodeless discharge lamp which is arranged in proximity to a power supply coil and is turned on, and a control means for blinking or time-divisionally controlling the output of a high-frequency power supply means in accordance with a control signal. The output applied to change the voltage applied to the high frequency power supply coil so that the voltage applied to the high frequency power supply coil increases as the output due to dimming decreases. An electrodeless discharge lamp lighting device comprising a voltage control means. 7. A power supply and a power supply from this power supply,
A high-frequency power supply means for outputting high-frequency power, a high-frequency power supply coil connected between the output terminals of the high-frequency power supply means, and a glass bulb filled with a discharge gas such as an inert gas or a metal vapor, An electrodeless discharge lamp lighting device provided with an electrodeless discharge lamp which is arranged in proximity to a power supply coil and is turned on, and a control means for blinking or time-divisionally controlling the output of a high-frequency power supply means in accordance with a control signal. In, the input current of the high frequency power supply means is increased during the ignition start period from immediately after the power is turned on until the electrodeless discharge lamp is lit,
An electrodeless discharge lamp lighting device comprising means for maintaining lighting by an efficient amplifying means after lighting. 8. The electrodeless discharge lamp lighting device according to claim 7, wherein the amplifying means comprises a class E amplifier circuit. 9. The electrodeless discharge lamp lighting device according to claim 7, wherein at least one constant of constituent elements of the amplifying means is changed during the ignition starting period. 10. The R provided in the amplifying means during the ignition starting period.
10. The electrodeless discharge lamp lighting device according to claim 7, wherein the constants of the F choke and the capacitor connected in parallel to the amplification element are changed. 11. The R provided in the amplifying means during the ignition starting period.
10. The electrodeless discharge lamp lighting device according to claim 7, wherein the constants of the F choke and the resonance capacitor are changed. 12. The R provided in the amplification means during the ignition starting period.
The electrodeless discharge lamp lighting device according to claim 7, 8 or 9, wherein the constant of the F choke and the resonance inductance is changed. 13. The R provided in the amplifying means during the ignition starting period.
13. The electrodeless discharge lamp lighting device according to claim 7, wherein the impedance of the F choke is changed so as to be decreased. 14. The electrodeless discharge lamp lighting device according to claim 7, 8 or 9, wherein the amplifying means for class C operation is operated during the ignition starting period. 15. The ignition starting period is 400 μs or less, and the ignition starting period is 400 μs or less.
Or the electrodeless discharge lamp lighting device according to 12 or 13 or 14.