Abstract: An electrodeless discharge lamp device comprises an induction coil, a pair of cores 1a, 1b, and thermal conductor 2. The cores 1a, 1b are configured to generate a high-frequency electromagnetic field for exciting a discharge gas with receiving a high frequency electric power. Each of the cores is arranged to give an overall circumference around which the induction coil is wound. The thermal conductor is formed into an approximately cylindrical shape and inserted into the space so as to be thermally coupled with the cores for radiating heat generated at the cores. The core has its inside face at least center portion of which is spaced radially from the thermal conductor by a predetermined distance.

Abstract: There is provided a discharge-lamp lighting device that, upon start-up of a high-intensity discharge lamp, alternately outputs a period A during which a starting circuit applies a high voltage to the high-intensity discharge lamp by resonance operation when a DC/AC inverter outputs a high-frequency voltage, and a period B during which the DC/AC inverter applies a low-frequency-square-wave voltage or a DC voltage to the high-intensity discharge lamp via the starting circuit. The period A for applying the high voltage by the resonance operation is set to about a time enough for a high-intensity discharge lamp in an initial aging stage to cause a dielectric breakdown, and a period C for alternately outputting the high-voltage generating period A and the period B for outputting the low-frequency-square-wave voltage or the DC voltage is set to about a time enough for a high-intensity discharge lamp in a life's last stage to cause a dielectric breakdown.

Abstract: When the starting of the discharge lamp has been detected at least once, the control circuit increases the number of repetitions of a period while the high frequency voltage and the square wave voltage are being outputted alternately. In such a way, in the discharge lamp lighting device that alternately generates the high frequency voltage and the square wave voltage at the time of starting, sure startability is ensured.

Abstract: In order to enhance stability of a discharge lamp at the time of dimming lighting even in the case where a light output is lowered, a direct current superimposing circuit superimposes a direct current voltage on an alternating current voltage applied to a fluorescent lamp, and a dimming signal correction circuit receives a detection value of a direct current voltage detection circuit and a dimming signal that is from an outside, outputs a dimming signal higher in level than the dimming signal in the case where the detection value of the direct current voltage detection circuit exceeds a first threshold value, and decreases the level of the outputted dimming signal to the level of the inputted dimming signal in the case where the detection value of the direct current voltage detection circuit falls down below a second threshold value that is equal to or less than the first threshold value.

Abstract: An electrodeless discharge lamp apparatus is provided which is increased in heat dissipation, making it possible to adapt to an increase in output of the apparatus. The electrodeless discharge lamp apparatus comprises a bulb containing a discharge gas and a coupler accommodated in a cavity formed in the bulb for generating a high frequency electromagnetic field. The coupler has: an induction coil; a core inserted into the coil; a heat conductor for conducting heat generated from the coil and the core; and a bobbin made of resin which accommodates the core and the heat conductor therein, and which has the coil wound therearound. The bobbin is designed to be separated in a radial direction of the coil, so that it is possible to separately mold the respective parts of the bobbin.

Abstract: An electrodeless discharge lamp is provided which prevents the problem of decrease in strength due to degradation of resin material, allowing secure fitting of a lamp part and a coupler member to a base even if it is used for a long time. A bulb containing a discharge gas and a coupler member for generating a high frequency electromagnetic field to excite the bulb are detachably fitted to each other via a base for fixing and supporting the bulb. The bulb and the base form a lamp part. The base comprises a base frame formed of a metal such as aluminum and a base cover formed e.g. of synthetic resin. The base frame has a coupler member fitting portion which is provided at a lower part thereof and fitted to the coupler member, wherein bulb fixing posts provided to stand on the coupler member fitting portion fix a bulb outer tube. Thus, the fitting portions of the lamp part and the coupler member to the base undergo less material degradation than a conventional one which uses a base of resin material.

Abstract: In order to enhance stability of a discharge lamp at the time of dimming lighting even in the case where a light output is lowered, a direct current superimposing circuit superimposes a direct current voltage on an alternating current voltage applied to a fluorescent lamp, and a dimming signal correction circuit receives a detection value of a direct current voltage detection circuit and a dimming signal that is from an outside, outputs a dimming signal higher in level than the dimming signal in the case where the detection value of the direct current voltage detection circuit exceeds a first threshold value, and decreases the level of the outputted dimming signal to the level of the inputted dimming signal in the case where the detection value of the direct current voltage detection circuit falls down below a second threshold value that is equal to or less than the first threshold value.

Abstract: In a discharge lamp lighting device that, at a time of starting a discharge lamp La, alternately repeats periods HF1 and HF2 while high frequency voltages are being outputted, in which a resonant circuit performs resonant operations, and periods FB1 and FB2 while square wave voltages are being outputted, and at a time of lighting the discharge lamp La, applies a low-frequency square wave voltage to the discharge lamp La through a starting circuit 4, there are provided: a starting detection circuit 5 that detects the starting of the discharge lamp La during the periods FB1 and FB2 while the square wave voltages are being outputted; and a control circuit 3C that stops the high frequency voltage or lowers a frequency of the high frequency voltage in the case where the starting of the discharge lamp La is detected.

Abstract: There is provided a discharge-lamp lighting device that, upon start-up of a high-intensity discharge lamp, alternately outputs a period A during which a starting circuit applies a high voltage to the high-intensity discharge lamp by resonance operation when a DC/AC inverter outputs a high-frequency voltage, and a period B during which the DC/AC inverter applies a low-frequency-square-wave voltage or a DC voltage to the high-intensity discharge lamp via the starting circuit. The period A for applying the high voltage by the resonance operation is set to about a time enough for a high-intensity discharge lamp in an initial aging stage to cause a dielectric breakdown, and a period C for alternately outputting the high-voltage generating period A and the period B for outputting the low-frequency-square-wave voltage or the DC voltage is set to about a time enough for a high-intensity discharge lamp in a life's last stage to cause a dielectric breakdown.

Abstract: An electrodeless discharge lamp apparatus is provided which is increased in heat dissipation, making it possible to adapt to an increase in output of the apparatus. The electrodeless discharge lamp apparatus comprises a bulb containing a discharge gas and a coupler accommodated in a cavity formed in the bulb for generating a high frequency electromagnetic field. The coupler has: an induction coil; a core inserted into the coil; a heat conductor for conducting heat generated from the coil and the core; and a bobbin made of resin which accommodates the core and the heat conductor therein, and which has the coil wound therearound. The bobbin is designed to be separated in a radial direction of the coil, so that it is possible to separately mold the respective parts of the bobbin.

Abstract: An electrodeless discharge lamp device comprises an induction coil, a pair of cores 1a, 1b, and thermal conductor 2. The cores 1a, 1b are configured to generate a high-frequency electromagnetic field for exciting a discharge gas with receiving a high frequency electric power. Each of the cores is arranged to give an overall circumference around which the induction coil is wound. The thermal conductor is formed into an approximately cylindrical shape and inserted into the space so as to be thermally coupled with the cores for radiating heat generated at the cores. The core has its inside face at least center portion of which is spaced radially from the thermal conductor by a predetermined distance.

Abstract: The object of the present invention is to provide a current detecting circuit capable of detecting a current flowing to a switching device with high accuracy, with less power loss, with high voltage, and in an insulated form. A current detecting circuit of the present invention is provided with a charge circuit charging to a capacitor through a current which is proportional to a voltage developed in a choke coil, and a discharge circuit setting a voltage of the capacitor 0V when the current flowing to the switching device is 0, so that the voltage of the capacitor is detected as a value which is proportional to the current flowing to the switching device.

Abstract: In an electrodeless discharge lamp suitable for use at a place with unfavorable environmental conditions or at a place where lamp replacement is difficult, the replacement of a lamp unit is facilitated and the lamp unit is prevented from falling off from a power coupler unit even if there is component deterioration caused by long-term use. A metallic elastic member is provided near a position on a metallic heat conduction member of the power coupler unit that is farthest from an electromagnetic field generating portion. In addition to an ordinary coupling structure between the power coupler unit and a coupling member, the elastic member is engaged with the coupling member of the lamp unit. When the lamp unit is mounted on or removed from the power coupler unit, a bulb of the lamp unit is turned relative to the power coupler unit about the axis and moved forward/backward in the direction of the axis.