JP3797434B2 - Electrodeless discharge lamp lighting device, electrodeless discharge lamp lighting device, and electrodeless discharge lamp illumination device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a lighting device for lighting an electrodeless discharge lamp and an electrodeless discharge lamp illumination device using the lighting device.
[0002]
[Prior art]
Conventionally, a lighting device for lighting an electrodeless discharge lamp receives an output of a fixed frequency transmitter such as a crystal oscillator, operates an inverter switching element, and magnetically couples the output of the inverter with an electrodeless discharge lamp. The discharge lamp is supplied to the excitation coil and the like, and the discharge lamp is lit in a frequency band near 13.56 MHz called, for example, an ISM band (industrial / scientific and medical frequency).
[0003]
Since the lighting device performs a switching operation in response to a fixed frequency, the frequency related to the output is stabilized, and the oscillation frequency falls within a required frequency range. Therefore, it has an excellent feature that no disturbing radio wave is output in a frequency band used in radio communication or the like.
[0004]
However, according to the above lighting device, the impedance between the lighting device and the discharge lamp is matched by a change in the frequency characteristics of the electrodeless discharge lamp having an inductance or a capacitance component, for example, a change due to the start of the discharge lamp or a change over time. Thus, the phase relationship between the voltage and current output from the lighting device changes.
[0005]
In particular, in the case of an electrodeless discharge lamp, since it is excited by a short wavelength electromagnetic wave such as a mega-Hz band, its impedance characteristic becomes steep, and if the above impedance mismatch occurs, the luminous efficiency decreases. As a matter of course, there is a problem that a large amount of reactive current flows and the elements of the lighting device are destroyed in the worst case.
[0006]
Therefore, as shown in Japanese Patent Application No. 4-172100, the present inventors detect the phase difference between the current and voltage output from the lighting device and set the lighting frequency so as to make the phase difference constant. I invented something to change.
[0007]
According to this structure, there is an advantage that generation of jamming radio waves can be suppressed to an extent that does not cause a problem, and destruction of the element can be prevented accurately corresponding to the frequency fluctuation of the electrodeless discharge lamp.
[0008]
[Problems to be solved by the invention]
However, in the above, circuit components such as a current detector, a voltage detector, and a phase comparator are indispensable, so that the circuit configuration tends to be complicated.
[0009]
The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to suppress generation of jamming radio waves to a level that does not cause a problem with a simple circuit configuration, and an electrodeless discharge lamp. It is an object to provide an electrodeless discharge lamp lighting device that can accurately prevent the destruction of elements in response to fluctuations in the frequency characteristics of the above and an electrodeless discharge lamp illumination device using the same.
[0010]
[Means for Solving the Problems]
The lighting device for an electrodeless discharge lamp according to claim 1 includes a fixed oscillation means including a crystal oscillator that oscillates at a fixed frequency, and a second oscillation that oscillates at a frequency different from the frequency oscillated by the fixed oscillation means. A power amplifying means capable of amplifying the outputs of the fixed oscillating means and the second oscillating means, a coupling means for supplying the output of the power amplifying means to the electrodeless discharge lamp, and a power supplied to the coupling means. detecting means for detecting a voltage or current, depending on the output of the detecting means, and selecting means for supplying to the power amplification means selects either the fixed oscillator means or the second oscillating means, by comprising the Features.
[0011]
An electrodeless discharge lamp lighting device according to claim 2 comprises the electrodeless discharge lamp lighting device according to claim 1 and an electrodeless discharge lamp energized by the output of the electrodeless discharge lamp lighting device. It is characterized by being.
[0014]
The electrodeless discharge lamp illumination device according to claim 3 is a fixed oscillation means comprising a crystal oscillator that oscillates at a fixed frequency, and a second oscillation means that oscillates at a frequency different from the frequency oscillated by the fixed oscillation means. A power amplifying means capable of amplifying the output supplied from the fixed oscillating means and the second oscillating means, a coupling means for radiating an electromagnetic wave by the output of the power amplifying means, and a voltage corresponding to the power supplied to the coupling means Alternatively, the detecting means for detecting the current, the selecting means for selecting either the fixed oscillating means or the second oscillating means to be supplied to the power amplifying means according to the output of the detecting means, and the light emitted by the output of the coupling means An electrodeless discharge lamp, and light control means for reflecting or transmitting light emitted from the electrodeless discharge lamp and radiating it outward are provided.
[0016]
Here, in the above description, changing the oscillation frequency transiently means changing the oscillation frequency to a frequency different from a substantially steady state.
[0017]
Here, in the above description, the light control means for reflecting or transmitting the light emitted from the electrodeless discharge lamp and radiating it outwardly typically reflects, for example, light emitted from the discharge lamp in order to obtain a desired light distribution. Reflective members such as reflectors and louvers, so-called optical filters and optical interference members that change spectral characteristics, and translucent members that transmit light substantially without any change in spectral characteristics, etc. .
[0018]
[Action]
For example, since the impedance characteristics of the electrodeless discharge lamp change greatly between the state before starting lighting and the state of stable lighting, when power is supplied from the lighting device, the voltage or The current changes. In other words, the impedance of the discharge lamp is substantially infinite in the state before starting lighting, whereas the impedance of the discharge lamp after starting lighting becomes small. The Q of the circuit will be reduced. Therefore, when starting the discharge lamp, the voltage of the electric power supplied from the lighting device decreases. In addition, when the impedances of the electrodeless discharge lamp and the lighting device are mismatched, the Q of the equivalent circuit including the discharge lamp as a load changes as described above, and the voltage or current also changes. .
[0019]
In the present invention, without detecting the phase difference between the current and the voltage accompanying the complexity of the circuit, the detection means detects the voltage or current accompanying the fluctuation of these impedance characteristics, and according to the output of the detection means, The selection means changes the oscillation frequency supplied to the power amplification means . Then, since the electrodeless discharge lamp is a load having an inductance or capacitance component, the impedance changes according to the frequency of the supplied power, and impedance mismatch between the lighting device and the discharge lamp can be improved. become.
[0020]
【Example】
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of an electrodeless discharge lamp lighting device and an electrodeless discharge lamp lighting device according to an embodiment of the present invention.
[0021]
In this embodiment, a crystal oscillator 1 that oscillates at a frequency fixed at 13.56 MHz and a voltage controlled oscillator (VCO) 3 that oscillates at a frequency corresponding to the control voltage output from the detection means 2 are provided. . One of the outputs of the crystal oscillator 1 and the voltage controlled oscillator 3 is selected by the switch 4 and is supplied to the power amplifier 5. The power amplifier 5 includes a switching element, is switched by receiving an oscillation output, and the output is supplied to the electrodeless discharge lamp 7 through a coupling means 6 constituted by, for example, an excitation coil.
[0022]
A voltage pickup unit 8 is provided in a line from the power amplifier 5 to the coupling means 6, and a voltage corresponding to the voltage supplied from the power amplifier 5 to the coupling means 6 is taken out. The extracted voltage is supplied to the detection means 2 and used for detecting the impedance fluctuation of the electrodeless discharge lamp 7 that is magnetically coupled to the coupling means 6. That is, when the impedance characteristic of the electrodeless discharge lamp 7 changes, the amount of power voltage related to the output of the power amplifier 5 changes due to a shift in the matching state. Therefore, the detection means 2 detects a change in the voltage amount and outputs a control voltage corresponding to the result. Specifically, for example, when the detected voltage exceeds a predetermined voltage value, a level at which a frequency of 15 MHz higher than the crystal oscillator 1 is oscillated is output to the voltage controlled oscillator 3, and the detected voltage is As the voltage approaches a predetermined voltage value, the control voltage is shifted in the direction of decreasing the oscillation frequency.
[0023]
Further, the lighting device is provided with a selection means 9 that inputs the output of the detection means 2 and controls the switch 4 in response to the output of the detection means 2. That is, when the control voltage output from the detection unit 2 matches a predetermined voltage value, the switch 4 is controlled to be switched to the crystal oscillator 1 side, and the control voltage output from the detection unit 2 is When the voltage value is different from the voltage value, the switch 4 is controlled to be switched to the voltage controlled oscillator 3 side so that one output of each of the oscillators 1 and 3 is supplied to the power amplifier 5.
[0024]
With the above operation, when there is an impedance mismatch between the lighting device and the electrodeless discharge lamp, power having a frequency corresponding to the voltage detected by the detection means is supplied, and the lighting device and the discharge lamp Impedance mismatch can be improved. Such an operation is a short time such as when the electrodeless discharge lamp is started, and even if an interference radio wave is generated, the influence on the radio wave communication is almost negligible.
[0025]
In addition, when the consistency is maintained, power of a fixed frequency is supplied, so that it is possible to suppress jamming radio waves, which is an advantage of oscillation by the fixed frequency. Next , a lighting device that helps the understanding of the present invention will be described with reference to FIG. Here, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. In this reference example, a high-pass filter 10 is provided for detecting when the power supplied to the coupling means 6 changes transiently, and only when there is a transient change in the voltage taken out by the voltage pickup unit 8. In addition, the voltage signal is input to the detecting means 2.
[0026]
When the voltage signal input through the high-pass filter 10 is zero, the detection means 2 outputs a control voltage so that the voltage-controlled oscillator 3 oscillates at a predetermined frequency fixed at 13.56 MHz, for example. When a voltage signal is given through the high-pass filter 10, a control voltage that increases the oscillation frequency of the voltage controlled oscillator 3 according to the voltage signal is output. That is, the voltage controlled oscillator 3 which is an oscillating means is configured to transiently change the oscillation frequency according to the output of the detecting means 2.
[0027]
With the above configuration, when the impedance of the electrodeless discharge lamp 7 changes greatly in a transient manner, the oscillation frequency is changed by the voltage control oscillator 3 to suppress impedance mismatch between the lighting device and the discharge lamp. Thus, when the electrodeless discharge lamp 7 is steadily lit and the impedance is matched, it is possible to suppress the jamming radio wave similarly to the fixed oscillation means in the above embodiment. However, when the voltage control oscillator 3 is a so-called feedback-type self-excited oscillation means, the output frequency is not constant due to component variations or the like, and it is difficult to suppress interference radio waves.
[0028]
Next, an embodiment of the electrodeless discharge lamp illumination device of the present invention will be described with reference to FIGS. That is, in the present embodiment, the electrodeless discharge lamp 7 includes a tubular glass tube in an electrodeless discharge lamp main body 7a in which a luminescent metal such as krypton gas and sodium iodide is hermetically sealed in a hollow quartz glass sphere. A starting thin tube 7b is joined to each other. Here, at the time of starting the discharge lamp 7, a high voltage is applied to the starting thin tube 7b to cause glow discharge, and plasma is induced in the discharge lamp main body 7a. Therefore, lighting power is radiated as an electromagnetic wave to the discharge lamp main body 7a. Electric power is supplied from an excitation coil 6 as a coupling means to a starter circuit configured by connecting a coil L1, a capacitor C2, and a resistor R1 in parallel via a capacitor C1. The excitation coil 6 is arranged so as to surround the discharge lamp main body 7a, and for example, a coil that is integrally formed in a coil shape so that a conductive metal such as aluminum is wound two to three turns is used. Further, the switch SW indicates a start switch.
[0029]
A capacitor Cp having a capacity of about 530 pF and a capacitor Cs are connected to the power supply side from the excitation coil 6 so as to constitute a T circuit, and function as a matching circuit. The output of the power amplifier 5 is supplied to the excitation coil 6 which is a coupling means from between the connection point of a pair of field effect transistors (FETs) T1 and T2 for switching and the source of one transistor T2 through the matching circuit. Is done. A power supply voltage VDD is applied between the source of the transistor T1 and the drain of the transistor T2, and a high frequency for switching is supplied from the driver 11 to the gates of the transistors T1 and T2.
[0030]
In this embodiment, the voltage supplied to the excitation coil 6 is taken in by dividing the voltage between the drain and source of the transistor T1 by the capacitors C3 and C4. The voltage taken in from the detection terminal 8 is output to the control means 14 constituted by the high pass filter 10, the comparator 12, and the low pass filter 13. That is, when the voltage changes transiently through the high-pass filter 10 as in the above-described embodiment, the high-pass filter 10 passes through the high-pass filter 10. Input to the terminal. A DC voltage corresponding to the normal operation of the electrodeless discharge lamp 7 is applied to the other terminal of the comparator 12 as a reference voltage VREF.
[0031]
The output of the comparator 12 is given to the low-pass filter 13, and the low-pass filter 13 integrates the output of the comparator 12 to create a DC voltage signal. The DC voltage signal is supplied to the voltage controlled oscillator 3 as a control voltage. Further, here, when the voltage signal input through the high-pass filter 10 is zero, the control means 14 performs direct current so that the voltage-controlled oscillator 3 oscillates at a predetermined frequency fixed at 13.56 MHz, for example. When a voltage signal is output and a voltage signal is given through the high-pass filter 10, a DC voltage signal that increases the oscillation frequency of the voltage-controlled oscillator 3 according to the voltage signal is output. That is, the control means 14 transiently changes the oscillation frequency of the voltage controlled oscillator 3 based on the voltage corresponding to the power output to the excitation coil 6, and when the electrodeless discharge lamp 7 is stably lit, A DC voltage signal is output so as to fix the oscillation frequency.
[0032]
A light control means for reflecting or transmitting light emitted from the electrodeless discharge lamp and radiating it outward will be described with reference to FIG. As shown in the figure, the socket 15 that supports the discharge lamp 7 by mechanically fixing the starting thin tube 7b of the electrodeless discharge lamp 7 has a bowl-shaped reflective shade whose inner surface has a reflective surface. It is attached to the center of 16. In addition, a front glass plate 17 in which a metal mesh (not shown) is embedded is disposed in the opening of the reflective shade 16 in order to prevent electromagnetic waves from leaking to the outside. The front glass plate 17 constitutes a light control means.
[0033]
Next, the operation of the electrodeless discharge lamp illumination device configured as described above will be described focusing on the lighting device portion. When the switch SW is closed, power is supplied to the resonance circuit including the capacitor C2, the coil L1, and the resistor R1 through the capacitor C1, thereby causing resonance. This resonance power is supplied to the starting thin tube 7b attached to the electrodeless discharge lamp 7 to cause glow discharge. This glow discharge, coupled with electromagnetic radiation from the excitation coil 6 to the electrodeless discharge lamp 7, induces a plasma discharge of the electrodeless discharge lamp 7, generating ring-shaped plasma and reaching a starting state.
[0034]
The impedance characteristics of the electrodeless discharge lamp 7 change from the start of the electrodeless discharge lamp 7 to the lighting thereof, and accordingly the drain-source voltage of the transistor T1 is divided by the voltage dividing capacitors C3 and C4. The voltage taken by the pressure fluctuates. Then, the voltage taken in from the detection end 8 passes through the high-pass filter 10 when the voltage changes transiently via the high-pass filter 10, and the output of the high-pass filter 10 is compared. When the electrodeless discharge lamp 7 operates normally, it is compared with a corresponding reference voltage VREF. The output of the comparator 12 is supplied to a low-pass filter 13, which integrates the output of the comparator 12 to create a DC voltage signal, and this DC voltage signal is used as a control voltage for a voltage controlled oscillator. 3 is supplied. Therefore, when the impedance of the electrodeless discharge lamp 7 has not changed, the voltage signal input through the high-pass filter 10 is zero, so the control means 14 is fixed at a predetermined 13.56 MHz, for example. A direct-current voltage signal is output so that the voltage controlled oscillator 3 oscillates at the generated frequency. Further, when a transient impedance fluctuation occurs at the time of starting the electrodeless discharge lamp 7, a voltage signal is given through the high pass filter 10, and the oscillation frequency of the voltage controlled oscillator 3 is set according to the voltage signal. It acts to output a DC voltage signal that increases. That is, the control means 14 transiently changes the oscillation frequency of the voltage controlled oscillator 3 based on the voltage corresponding to the power output to the excitation coil, and when the electrodeless discharge lamp 7 is stably lit, the oscillation A DC voltage signal is output so as to fix the frequency.
[0035]
As described above, when the impedance of the electrodeless discharge lamp fluctuates greatly in a transient manner, the voltage-controlled oscillator changes the oscillation frequency and works to suppress impedance mismatch between the lighting device and the discharge lamp, When the electrodeless discharge lamp is steadily lit and the impedance is matched, it is possible to suppress jamming radio waves as in the case of the fixed oscillation means.
[0036]
In the above embodiment, the detection of the voltage supplied to the coupling means or the control of the oscillating means based on the voltage is specifically described. However, the current detection means is connected to the current path to the coupling means. May be provided to detect the current, and similarly, the oscillation means may be controlled based on the current.
[0037]
In the above, the coupling means and the power amplifier can be connected with an extension cable having a fixed characteristic impedance such as a coaxial cable, so that the electric circuit portion and the lamp portion including the electrodeless discharge lamp can be separated. . In this case, the circuit constant of the matching circuit formed by the capacitor Cp and the capacitor Cs may be configured to be changed so as to match the characteristic impedance of the cable. Specifically, for example, an auxiliary capacitor may be connected to each of the capacitors Cp and Cs in parallel via a switch to control on / off of the switch. Furthermore, the circuit constant of the matching circuit may be changed in accordance with the operating state of the discharge lamp by detecting the start-up or lighting state of the discharge lamp with existing means.
[0038]
【The invention's effect】
As described above, according to the present invention, the generation of jamming radio waves can be suppressed to a level that does not cause a problem with a simple circuit configuration, and the element can be accurately handled in response to fluctuations in the frequency characteristics of the electrodeless discharge lamp. An electrodeless discharge lamp lighting device, an electrodeless discharge lamp lighting device, and an electrodeless discharge lamp illumination device using the same can be provided.
[Brief description of the drawings]
FIG. 1 is a circuit block diagram showing an embodiment of an electrodeless discharge lamp lighting device and an electrodeless discharge lamp lighting device according to the present invention. FIG. 2 is a circuit block diagram showing a lighting device that helps understanding of the present invention. FIG. 3 is a diagram showing a circuit of an embodiment of the electrodeless discharge lamp discharge lamp illumination device of the present invention. FIG. 4 is a schematic diagram showing a light control means of the embodiment of the electrodeless discharge lamp discharge lamp illumination device of the present invention.

Claims (3)

Fixed oscillation means comprising a crystal oscillator that oscillates at a fixed frequency;
Second oscillating means that oscillates at a frequency different from the frequency oscillated by the fixed oscillating means;
Power amplifying means capable of amplifying outputs of the fixed oscillating means and the second oscillating means;
Coupling means for supplying the output of the power amplification means to the electrodeless discharge lamp;
Detection means for detecting a voltage or current according to the power supplied to the coupling means;
Depending on the output of the detection means, by selecting one of the fixed oscillator means or the second oscillating means and the selection means to supply to the power amplifier means;
An electrodeless discharge lamp lighting device comprising: A lighting device for an electrodeless discharge lamp according to claim 1;
An electrodeless discharge lamp energized by the output of the lighting device for the electrodeless discharge lamp;
An electrodeless discharge lamp lighting device comprising: Fixed oscillation means comprising a crystal oscillator that oscillates at a fixed frequency;
  Second oscillating means that oscillates at a frequency different from the frequency oscillated by the fixed oscillating means;
  Power amplification means capable of amplifying the output supplied from the fixed oscillation means and the second oscillation means;
  Coupling means for radiating electromagnetic waves by the output of the power amplification means;
  Detection means for detecting a voltage or current according to the power supplied to the coupling means;
  Selecting means for selecting either the fixed oscillating means or the second oscillating means and supplying the selected power to the power amplifying means according to the output of the detecting means;
  An electrodeless discharge lamp that emits light by the output of the coupling means;
  Light control means for reflecting or transmitting light emitted from the electrodeless discharge lamp and radiating outward;
An electrodeless discharge lamp illumination device comprising:

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