JP2007287573A - Electrodeless discharge lamp lighting device and luminaire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce electromagnetic noise generated in a power supply circuit, improve moisture resistance and vibration resistance, and stably supply a starting voltage to an induction coil. <P>SOLUTION: A mounting substrate 46 with the power supply circuit 40, a detection circuit 43 and a control circuit 44 mounted thereon is housed in a metallic case 47. With a rise in temperature, the dielectric constant of a filler 48 decreases while the capacitance value of a ground capacitor 450 increases. In an electrodeless discharge lamp lighting device 4, when the induction coil 41 has produced a high frequency magnetic field in an electrodeless discharge lamp 1 by means of a high frequency current supplied from the power supply circuit 40, a stray capacitance is generated between the mounting substrate 46 and the metallic case 47. As a result, a stray current is fed from the induction coil 41 to the mounting substrate 46 via a heat sink 42, a conductive member 34 and the stray capacitance, and is superimposed on a detection current fed from the detection circuit 43. While minimizing the stray current against a temperature rise, the control circuit 44 controls the power supply circuit 40 so that the magnitude of the starting voltage V1 can be varied. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrodeless discharge lamp lighting device and a lighting fixture.

  Conventionally, this type of electrodeless discharge lamp lighting device has a configuration in which a stable potential of a power supply circuit and a metal case are connected via a grounding capacitor (see Patent Document 1). Thereby, electromagnetic noise generated in the power supply circuit can be reduced, and a filter element and the like necessary for the power supply circuit can be simplified. In addition, the conventional electrodeless discharge lamp lighting device is a metal case that houses a mounting substrate on which a detection circuit, a control circuit, and the like are mounted (see Patent Document 2). Thereby, the moisture resistance and vibration resistance of the mounting substrate and circuit components can be improved.

  On the other hand, the electrodeless discharge lamp has a feature that it has a longer life than a general lighting lamp. Some commercially available electrodeless discharge lamps have a life of over 60000 hours and do not require lamp replacement during that period. For example, in the case of a lifetime of 60,000 hours, even if lighting is performed for 10 hours per day, it is not necessary to replace the lamp for 16 years, and the entire luminaire becomes a lifetime after 16 years. Electrodeless discharge lamps take advantage of their long life characteristics and are often used in places where maintenance work is difficult, such as road lights, high ceiling lights, and street lights. For this reason, long life and high reliability are also required for the electrodeless discharge lamp lighting device.

  Since the electrodeless discharge lamp has no electrode inside, it is necessary to apply a higher starting voltage to the induction coil than a general fluorescent lamp when starting the electrodeless discharge lamp. Therefore, it is necessary to design an electrodeless discharge lamp lighting device that sharpens resonance and applies a high starting voltage with low loss when starting the electrodeless discharge lamp. Here, the sharp resonance means that the starting voltage is greatly fluctuated with respect to minute fluctuations in frequency, element parameters, and the like. In order to stably apply such a high starting voltage, the electrodeless discharge lamp lighting device includes a detection circuit that detects the starting voltage of the induction coil and a control circuit that controls the power supply circuit. Here, in order for the control circuit to detect a high starting voltage with low loss when starting the electrodeless discharge lamp, a detection circuit having a high impedance connects the induction coil and the control circuit. When the electrodeless discharge lamp is started, the detection circuit detects the starting voltage, and feedback is performed by the control circuit so that a desired starting voltage is applied to the induction coil.

In the conventional electrodeless discharge lamp lighting device, the induction coil receives radiant heat from the electrodeless discharge lamp by being close to the electrodeless discharge lamp in order to generate a high-frequency magnetic field in the electrodeless discharge lamp. In order to reduce the temperature rise of the induction coil due to radiant heat, a metal radiator is provided in the vicinity of the induction coil to discharge the heat of the induction coil to the outside.
Japanese Patent No. 3463482 (pages 4, 5 and 2) JP-A-7-226465 (page 4 and FIG. 1)

  In the conventional electrodeless discharge lamp lighting device, a relatively large first stray capacitance is generated by arranging the induction coil and the heat dissipator closely in order to enhance the thermal coupling. As a result, when the stable potential of the power supply circuit and the metal case are connected via a grounding capacitor, the first stray capacitance and the stable potential of the power supply circuit and the induction coil are between the stable potential and the induction coil when the electrodeless discharge lamp is started. A ground current flows through the ground capacitor. For this reason, in order to set the starting voltage to a desired value when starting the electrodeless discharge lamp, the control circuit is designed in consideration of the influence of the detection current from the detection circuit and the ground current.

  On the other hand, since the dielectric constant of the filler is larger than that of air, the grounding capacitor is connected in parallel between the mounting board on which the power supply circuit is mounted and the metal case facing the mounting board, compared to the case where no filler is used. The capacitance value of the generated second stray capacitance increases. Due to the first stray capacitance and the second stray capacitance, the stray current flows by the same mechanism as the ground current.

  Accordingly, the conventional electrodeless discharge lamp lighting device has the following problems. Unlike the ground current that flows to the stable potential of the power supply circuit through the ground capacitor, the floating current flows to the detection circuit and the control circuit on the mounting substrate facing the metal case and is superimposed on the detection current. Here, the detection current input to the control circuit is a very small value because it is input from the detection circuit having a high impedance in order to detect the starting voltage with low loss. The stray current makes it difficult to stably apply a desired starting potential to the induction coil at the start of sharp resonance of the electrodeless discharge lamp lighting device. More specifically, when a ceramic capacitor is used as the grounding capacitor, the starting voltage decreases when the ambient temperature increases from room temperature (25 ° C.) to high temperature (60 ° C.) (see “First Conventional FIG. 6”). (See Morphological Characteristics). This is because when the capacitance value of the ceramic capacitor decreases as the temperature rises, the ground current decreases and the floating current increases. Furthermore, the starting voltage when filling with a urethane resin as a filler is lower than when the ambient temperature is increased from room temperature (25 ° C.) to a high temperature (60 ° C.) than when not being filled with a filler. (See “Characteristics of Second Conventional Mode” in FIG. 6). This is because the stray current is increased by increasing the capacitance value of the stray capacitance due to the filler. When the decrease in the starting voltage falls below the voltage necessary for starting the electrodeless discharge lamp, a starting failure of the electrodeless discharge lamp occurs.

  As described above, the start-up failure of the electrodeless discharge lamp occurs at a high temperature even before the electrodeless discharge lamp lighting device reaches the end of its life. It will damage the sex. Here, in order to compensate for a decrease in starting voltage at high temperatures, when designed to generate a higher starting voltage from room temperature, a lot of stress is applied to the circuit elements to be used to protect the circuit elements. The circuit element and the mounting board for mounting it had to be made large.

  The present invention has been made in view of the above points. The object of the present invention is to reduce electromagnetic noise generated by a power supply circuit by a relatively simple and inexpensive method, and to have moisture resistance and vibration resistance. It is an object of the present invention to provide an electrodeless discharge lamp lighting device and a lighting fixture capable of stably supplying a starting voltage while improving.

  The electrodeless discharge lamp lighting device according to claim 1 is an electrodeless discharge lamp lighting device that controls lighting of an electrodeless discharge lamp that is turned on when a high-frequency magnetic field is generated, in proximity to the electrodeless discharge lamp. An induction coil that generates the high-frequency magnetic field in the electrodeless discharge lamp when the high-frequency current is supplied, a radiator that is disposed in proximity to the induction coil and dissipates heat from the induction coil, and the induction coil A power supply circuit that applies a voltage to supply the high-frequency current, and a detection that detects a starting voltage applied to the induction coil when the electrodeless discharge lamp is started and outputs a detection current corresponding to the magnitude of the starting voltage A control circuit that inputs the detection current from the detection circuit and controls the power supply circuit to vary the magnitude of the starting voltage based on the detection current; at least the detection circuit and the front A mounting board on which a control circuit is mounted, a metal case that houses the mounting board and transmits heat from the radiator, and fills the metal case so as to seal at least the mounting board. A filler having a relative dielectric constant that decreases accordingly, and a grounding capacitor that is provided between the output side of the power supply circuit and the metal case and that increases in capacitance as the temperature rises.

  According to this configuration, the electromagnetic noise generated in the power supply circuit can be reduced by the grounding capacitor, the moisture resistance and vibration resistance can be improved by the filler, and the floating generated between the mounting board and the metal case can be improved. Since the stray current flowing from the induction coil to the mounting board via the capacitor and the heat sink can be reduced, the decrease in starting voltage caused by the stray current superimposed on the detection current on the mounting board is reduced. The starting voltage can be stably supplied to the induction coil.

  The invention of the electrodeless discharge lamp lighting device according to claim 2 is the invention according to claim 1, wherein, at a temperature higher than room temperature, the absolute value of the ratio of the increase of the capacitance value to the room temperature is the relative dielectric constant. It is characterized by being smaller than the absolute value of the ratio of the decrease of room temperature to room temperature. According to this configuration, an increase in leakage current generated in the grounding capacitor can be suppressed. Further, since the capacitance value of the grounding capacitor is larger than the capacitance value of the stray capacitance, the stray current can be sufficiently reduced even if the ratio of the increase in the capacitance value of the grounding capacitor to the room temperature is small.

  The invention of the electrodeless discharge lamp lighting device according to claim 3 is characterized in that, in the invention according to claim 1 or 2, the dielectric of the grounding capacitor is a polyester film. According to this configuration, the capacitance value of the grounding capacitor can be reliably increased at a high temperature, so that the decrease due to the temperature increase of the starting voltage can be compensated, and the starting voltage can be supplied to the induction coil more stably. Can do.

  The invention of the electrodeless discharge lamp lighting device according to claim 4 is characterized in that, in the invention according to any one of claims 1 to 3, the filler is urethane. According to this configuration, since the inhibition of curing can be reduced, the options of parts and structural materials to be used can be expanded, and the optimal parts and structural materials can be used from among the options.

  The invention of the lighting fixture according to claim 5 is an electrodeless discharge lamp lighting device according to any one of claims 1 to 4, an electrodeless discharge lamp that is lit when a discharge gas is enclosed therein and a high-frequency magnetic field is generated, and It is characterized by providing.

  According to this configuration, in the electrodeless discharge lamp lighting device, the electromagnetic noise generated in the power supply circuit can be reduced by the grounding capacitor, and the moisture resistance and vibration resistance can be improved by the filler, and the mounting substrate and the metal can be improved. The stray current that flows from the induction coil to the mounting board through the stray capacitance generated between the case and the heat sink can be reduced, so that the stray current generated on the mounting board is superimposed on the detected current. The voltage drop can be reduced, and this starting voltage can be stably supplied to the induction coil. Thereby, a lighting fixture can start an electrodeless discharge lamp normally.

  The invention of a lighting fixture according to claim 6 is provided with a metal fixture body in which the electrodeless discharge lamp lighting device is installed in connection with the radiator and the metal case in the invention of claim 5. It is characterized by. According to this configuration, it is not necessary to separately prepare means such as an electric wire in order to connect to the radiator and the metal case. Moreover, since the instrument body has a cross-sectional area larger than that of the electric wire, the high frequency impedance can be lowered from the electric wire, electromagnetic noise can be reduced, and the thermal conductivity of the radiator can be improved. More heat from the induction coil can be dissipated to reduce the heat of the induction coil.

  According to the present invention, electromagnetic noise generated in the power supply circuit can be reduced, moisture resistance and vibration resistance can be improved, and a starting voltage can be stably supplied to the induction coil.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a circuit diagram of the lighting fixture of the present embodiment. FIG. 2 is a half sectional view of the lighting fixture of the present embodiment. FIG. 3 is a cross-sectional view of the electrodeless discharge lamp lighting device of the present embodiment. FIG. 4 is a diagram showing the dielectric constant of the filler of the present embodiment. FIG. 5 is a diagram showing the stray capacitance of the electrodeless discharge lamp lighting device of the present embodiment. FIG. 6 is a diagram illustrating a voltage applied to the dielectric coil at the start of the present embodiment.

  First, the basic configuration of this embodiment will be described. The lighting fixture of this embodiment is provided with the electrodeless discharge lamp 1, the coupler 2, the lamp 3, and the electrodeless discharge lamp lighting device 4 as shown in FIG.

  The electrodeless discharge lamp 1 includes a bulb 10 and is controlled to be lit by an electrodeless discharge lamp lighting device 4. The bulb 10 is made of a translucent material such as translucent glass and has a spherical upper portion. The valve 10 is formed with a bottomed cylindrical cavity (not shown) in the vertical direction. A discharge gas is sealed inside the bulb 10, and a phosphor film and a protective film are applied to the inner surface of the bulb 10. The discharge gas is an ionizable gas containing, for example, mercury, a rare gas, a metal halide, or the like. The electrodeless discharge lamp 1 is lit when a high frequency magnetic field is generated inside the bulb 10. Specifically, a high-frequency magnetic field ionizes discharge gas atoms to generate electrons, the generated electrons collide with another discharge gas atom, and the collided discharge gas atom is ionized to generate new electrons. appear. At this time, the electrons receive energy by the high frequency magnetic field and collide with the atoms of the discharge gas to give the energy. Due to such collision, the atoms of the discharge gas repeat excitation and relaxation, and ultraviolet light or visible light is generated from the discharge gas when the excited atoms relax.

  The coupler 2 includes a bobbin 20. The bobbin 20 is formed of, for example, resin, and integrally includes a base portion 200 having a circular cross section and a cylindrical portion 201 extending upward from the inner peripheral edge of the base portion 200. The bobbin 20 is coupled to the electrodeless discharge lamp 1 such that the cylindrical portion 201 is accommodated in a hollow portion (not shown) of the electrodeless discharge lamp 1.

  The lamp 3 includes a lamp main body 30, a globe 31, a diffusion plate 32, and a shade 33. The lamp body 30 is formed of, for example, a metal material, and a conductive member 34 on which the coupler 2 is installed is provided at the upper end. The conductive member 34 is formed of a metal member such as a steel plate or an aluminum plate. A screw hole 340 is formed in the conductive member 34. In addition, the conductive member 34 connects a heat radiator 42 and a metal case 47 described later. The lamp body 30 is provided with a coupler 2 and an electrodeless discharge lamp lighting device 4. The globe 31 is formed in a truncated cone shape with a translucent resin such as polycarbonate or acrylic, and is joined to the lamp body 30 at the lower end. An opening 310 is formed in the globe 31, and the electrodeless discharge lamp 1, the coupler 2, the diffusion plate 32, and the electrodeless discharge lamp lighting device 4 are accommodated in the opening 310. A screw hole 311 is formed on the outer peripheral edge of the upper end of the globe 31. The diffusing plate 32 is formed of a resin having translucency such as polycarbonate or acrylic, and includes a truncated cone-shaped cylindrical portion 320 and an attachment portion 321 extending inward from the lower end of the cylindrical portion 320. Yes. A screw hole 322 is formed in the attachment portion 321. The diffusion plate 32 is screwed and fixed to the conductive member 34 of the lamp body 30 by screwing the screws 323 into the screw holes 322 and 340. At this time, the cylindrical portion 320 is disposed so as to surround the lower side of the electrodeless discharge lamp 1. The shade 33 is formed of a metal material or a resin, for example, in a circular arc shape in cross section. A plurality of through holes 330 are formed on the outer peripheral edge of the shade 33. The cap 33 is screwed and fixed to the globe 31 so as to cover the upper surface of the globe 31 by inserting a screw 331 into the through-hole 330 and fitting it into the screw hole 311.

  As shown in FIG. 1, the electrodeless discharge lamp lighting device 4 includes a power circuit 40, an induction coil 41, a radiator (thermal conductor) 42, a detection circuit 43, a control circuit 44, and a ground circuit 45. A mounting substrate 46 and a metal case 47 are provided, connected to an AC power source AC, and the lighting control of the electrodeless discharge lamp 1 is performed. The AC power source AC is, for example, a commercial power source. A power supply circuit 40, a detection circuit 43, a control circuit 44, and a ground circuit 45 are mounted on the mounting board 46.

  As shown in FIG. 2, the metal case 47 is formed in a box shape with a metal material having a high thermal conductivity such as aluminum, and is electrically connected to the conductive member 34 and stored in the lamp body 30. That is, the metal case 47 is connected to the heat radiating body 42 via the conductive member 34, and heat from the heat radiating body 42 is transmitted. Further, as shown in FIG. 3, the metal case 47 houses a mounting substrate 46, and the mounting substrate 46 is sealed with a filler 48. As the filler 48, a material having a relative dielectric constant of 3 or more at room temperature and decreasing as the temperature rises is used. Among the materials having the above characteristics, urethane resin is more suitable, and urethane resin is used as the filler 48 of this embodiment. FIG. 4 shows the change characteristic of the dielectric constant with respect to the temperature of the urethane resin used as the filler 48. The absolute value of the ratio of the decrease at 60 ° C. to 20 ° C. of the filler 48 of the present embodiment is about 10%. In addition, although the material of the filler 48 is more suitable for the urethane resin, it is not limited to the urethane resin, and any material that has a relative dielectric constant of 3 or more at room temperature and decreases as the temperature rises may be used. Depending on the application, it is appropriately selected.

  As shown in FIG. 1, the power supply circuit 40 is a circuit including a DC power supply circuit (not shown), an inverter circuit (not shown), and a resonance circuit (not shown) in order from the AC power supply AC side. is there. The DC power supply circuit converts AC power from the AC power supply AC into DC power, boosts the converted DC power, smoothes the boosted DC power, and converts the smoothed DC power (DC current) to the inverter circuit. Output. The inverter circuit converts DC power from the DC power supply circuit into high-frequency power for applying a high-frequency magnetic field to the electrodeless discharge lamp 1, and outputs the converted high-frequency power to the resonance circuit. The resonance circuit is designed to output high-frequency power having a large amplitude in the vicinity of the resonance frequency, is connected to the induction coil 41 on the output end side, and the high-frequency power is supplied to the induction coil 41 based on the frequency of the high-frequency power from the inverter circuit. A high frequency current is supplied by applying a voltage. In particular, the resonance circuit outputs a high-frequency high-frequency current to the induction coil 41 when the electrodeless discharge lamp 1 is started. The operating frequency of the power supply circuit 40 is 50 kHz to 100 kHz.

  As shown in FIG. 2, the induction coil 41 is formed by winding a conductive wire such as copper or a copper alloy around the cylindrical portion 201 of the bobbin 20, and a hollow portion (not shown) of the electrodeless discharge lamp 1. Is arranged. The induction coil 41 generates a high-frequency magnetic field inside the bulb 10 of the electrodeless discharge lamp 1 when a high-frequency current is supplied from the power supply circuit 40 (see FIG. 1). The core 410 is made of a material having good high-frequency magnetic characteristics such as a soft magnetic material, and efficiently generates a high-frequency magnetic field from the induction coil 41. Examples of the material of the core 410 include manganese zinc ferrite (Mn—Zn ferrite) and nickel zinc ferrite (NiZn ferrite). Thereby, loss can be reduced. The core 410 is in contact with the radiator 42 in a planar shape, and is held while radiating the generated heat to the radiator 42 described later.

  The radiator 42 is made of a material having high thermal conductivity such as aluminum, copper, or an alloy thereof, for example, is provided along the outer peripheral surface of the cylindrical portion 201 of the bobbin 20, and is disposed close to the induction coil 41. Yes. The radiator 42 radiates heat from the induction coil 41.

  As shown in FIG. 1, the detection circuit 43 detects a starting voltage V1 applied to the induction coil 41 when the electrodeless discharge lamp 1 is started, and generates a detection current I1 proportional to the detected starting voltage V1. Output to the control circuit 44. The control circuit 44 receives the detection current I1 from the detection circuit 43 at least when the electrodeless discharge lamp 1 is started, and varies the frequency of the high-frequency power generated in the induction coil 41 based on the input detection current I1. The inverter circuit (not shown) of the power supply circuit 40 is controlled so as to vary the magnitude of the starting voltage V1.

  The ground circuit 45 includes a ground capacitor 450 provided between the output side of the power supply circuit 40 and the metal case 47. As the grounding capacitor 450, a capacitor whose capacitance value is 10 times or more of the capacitance value of the second stray capacitance 51 described later and that becomes smaller than 2 nF at room temperature (for example, 25 ° C.) and increases as the temperature rises is used. In addition, at a temperature higher than room temperature, the absolute value of the increase ratio of the capacitance value of the grounding capacitor 450 to the room temperature is smaller than the absolute value of the decrease ratio of the relative permittivity of the filler 48 to the room temperature. A polyester film is more suitable as the dielectric of the grounding capacitor 450 having the above characteristics, and a polyester film is used as the dielectric of the grounding capacitor 450 of the present embodiment. The absolute value of the ratio of the increase at 60 ° C. to 20 ° C. of the grounded capacitor 450 of the present embodiment is about 1%, and the absolute value of the ratio of the decrease of the filler 48 to 20 ° C. at 20 ° C. (FIG. 4). In addition, although the polyester film is more suitable for the dielectric of the grounding capacitor 450, it is not limited to the polyester film, as long as the capacitance value increases as the temperature rises and is appropriately selected according to the application. Is done.

  Next, the stray capacitance generated in the electrodeless discharge lamp lighting device 4 of the present embodiment having the above configuration will be described with reference to FIG. In the electrodeless discharge lamp lighting device 4 of the present embodiment, as shown in FIG. 5, a first stray capacitance 50 is generated between the induction coil 41 and the radiator 42 (see FIG. 1), and the mounting substrate 46. A second stray capacitance 51 is generated between (see FIG. 1) and the metal case 47 (see FIG. 1). The second stray capacitance 51 is generated so as to be connected in parallel to the grounding capacitor 450.

  The stray current I2 flowing through the second stray capacitance 51 varies depending on the capacitance values of the ground capacitor 450 and the second stray capacitance 51. Specifically, when the capacitance value of the ground capacitor 450 is reduced, the ground current I3 flowing through the ground capacitor 450 is reduced, and the current decrease is passed through the second stray capacitance 51, so that the floating current I2 is increased. On the other hand, when the capacitance value of the ground capacitor 450 increases, the ground current I3 increases and the floating current I2 decreases. On the other hand, when the capacitance value of the second stray capacitance 51 increases, the stray current I2 increases. When the capacitance value of the second stray capacitance 51 decreases, the stray current I2 decreases. Here, the capacitance value of the second stray capacitance 51 varies depending on the dielectric constant of the filler 48 (see FIG. 4). Specifically, the capacitance value of the second stray capacitance 51 decreases as the temperature increases, and increases as the temperature decreases.

  The floating current I2 is superimposed on the detection current I1 on the mounting substrate 46 (see FIG. 1). The superimposed current is input to the control circuit 44 as a detection current. FIG. 6 shows the characteristics of the starting voltage of this embodiment together with the characteristics of the starting voltage of the first conventional embodiment and the characteristics of the starting voltage of the second conventional embodiment. In the first conventional embodiment, a ceramic capacitor is used as a grounding capacitor and is not filled with a filler. The second conventional embodiment uses a ceramic capacitor as a grounding capacitor and is filled with a filler. In the control circuit 44, the magnitude of the starting voltage with respect to the input current is designed in consideration of the detection current I1, the floating current I2, and the ground current I3 at 25 ° C. The temperature change of the starting voltage of this embodiment is smaller than the temperature change of the starting voltage of the first conventional embodiment and the second conventional embodiment.

  As described above, according to the present embodiment, electromagnetic noise generated in the power supply circuit 40 can be reduced by the grounding capacitor 450, and the moisture resistance and vibration resistance can be improved by the filler 48, and the mounting substrate 46 and the metal case can be improved. 47, the stray current flowing from the induction coil 41 to the mounting substrate 46 via the second stray capacitance 51 and the heat radiating body 42 can be reduced, so that the stray current I2 is detected on the mounting substrate 46. A decrease in the starting voltage V1 generated by superimposing the current I1 can be reduced, and the starting voltage V1 can be stably supplied to the induction coil 41. Thereby, the electrodeless discharge lamp 1 can be started normally. Further, an increase in leakage current generated in grounding capacitor 450 can be suppressed. Furthermore, since the capacitance value of the ground capacitor 450 is larger than the capacitance value of the second stray capacitance 51, the stray current I2 can be made sufficiently small even if the ratio of the increase in the capacitance value of the ground capacitor 450 to the room temperature is small. it can.

  In addition, since the dielectric of the grounding capacitor 450 is a polyester film, the capacitance value of the grounding capacitor 450 can be reliably increased at a high temperature, so that a decrease due to the temperature increase of the starting voltage V1 can be compensated. The voltage V1 can be supplied to the induction coil 41 more stably. Furthermore, since the filler 48 is a urethane resin, the inhibition of curing can be reduced, so the options for the parts and structural materials to be used can be expanded, and the optimum parts and structural materials can be used from among the options. it can. On the other hand, if the filler is silicon resin or silicon rubber with a low dielectric constant, the choice of parts and structural materials that can be used due to inhibition of curing will be narrowed, and optimal parts and structural materials should be used. It becomes impossible.

  In addition to the above, it is not necessary to separately prepare means such as an electric wire in order to connect to the radiator 42 and the metal case 47. Moreover, since the lamp body 30 has a cross-sectional area larger than that of the electric wire, the high frequency impedance can be lowered from the electric wire, electromagnetic noise can be reduced, and the thermal conductivity of the radiator 42 can be improved. It is possible to release more heat from the induction coil 41 and lower the heat of the induction coil 41. In particular, when the induction coil 41 is accommodated in the cavity (not shown) of the electrodeless discharge lamp 1 as in the present embodiment, it has a great effect in solving the difficulty of heat dissipation. By reducing the heat of the induction coil 41, the heat-resistant temperature of the members constituting the induction coil 41 can be lowered, and the cost of the induction coil 41 can be reduced. Furthermore, since the operating frequency of the electrodeless discharge lamp lighting device 4 is set to 500 kHz or less, the heat dissipation and noise prevention of the conductive member 34 can be improved.

It is a circuit diagram of the lighting fixture of embodiment by this invention. It is a half sectional view of a lighting fixture same as the above. It is sectional drawing of the electrodeless discharge lamp lighting device same as the above. It is a figure which shows the dielectric constant of a filler same as the above. It is a figure which shows the stray capacity of the electrodeless discharge lamp lighting device same as the above. It is a figure which shows the voltage applied to a dielectric coil at the time of starting same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrodeless discharge lamp 34 Conductive member 4 Electrodeless discharge lamp lighting device 40 Power supply circuit 41 Inductive coil 42 Radiator 43 Detection circuit 44 Control circuit 450 Grounding capacitor 46 Printed circuit board 47 Metal case 48 Filler 50 First stray capacitance 51 Second stray capacitance V1 Starting voltage I1 Detection current I2 Floating current I3 Ground current

Claims (6)

An electrodeless discharge lamp lighting device that controls lighting of an electrodeless discharge lamp that is turned on when a high-frequency magnetic field is generated,
An induction coil that is arranged close to the electrodeless discharge lamp and generates the high frequency magnetic field in the electrodeless discharge lamp when a high frequency current is supplied;
A radiator disposed near the induction coil to dissipate heat from the induction coil;
A power supply circuit that applies a voltage to the induction coil to supply the high-frequency current;
A detection circuit that detects a starting voltage applied to the induction coil at the start of the electrodeless discharge lamp and outputs a detection current according to the magnitude of the starting voltage;
A control circuit that inputs the detection current from the detection circuit and controls the power supply circuit to vary the magnitude of the starting voltage based on the detection current;
A mounting substrate on which at least the detection circuit and the control circuit are mounted;
A metal case that houses the mounting substrate and that transfers heat from the radiator;
A filler filled in the metal case so as to seal at least the mounting substrate and having a relative dielectric constant that decreases with increasing temperature; and
An electrodeless discharge lamp lighting device comprising: a grounding capacitor provided between the output side of the power supply circuit and the metal case and having a capacitance value that increases as the temperature rises.   2. The electrodeless discharge according to claim 1, wherein an absolute value of a ratio of an increase of the capacitance value to the room temperature is lower than an absolute value of a ratio of a decrease of the relative dielectric constant to the room temperature at a temperature higher than the room temperature. Electric light lighting device.   3. The electrodeless discharge lamp lighting device according to claim 1, wherein the dielectric of the grounding capacitor is a polyester film.   The electrodeless discharge lamp lighting device according to claim 1, wherein the filler is urethane. The electrodeless discharge lamp lighting device according to any one of claims 1 to 4,
An illuminating device comprising: an electrodeless discharge lamp that is turned on when a discharge gas is sealed inside and a high-frequency magnetic field is generated.   The lighting fixture according to claim 5, further comprising a metal fixture main body that is connected to the radiator and the metal case to install the electrodeless discharge lamp lighting device.

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