Abstract: An electronic horn for use, e.g., in a vehicle, includes a piezoelectric element (52) that excites a plate-shaped oscillator (51). A resonator (7) is provided with an opening (71) and covers forward of the oscillator such that a resonance space (S) is defined between the resonator and the oscillator. An inner cylinder (62) and an outer conical housing (63) are provided concentrically around the resonator. A circular cover (8) covers the inner cylinder (62) and the outer conical housing (63) from the front, such that a buffer chamber (BR), at least one first sound amplifying chamber (MH1), and a second sound amplifying chamber (MH2) are defined around an entire circumference of the opening of the resonator.

Abstract: An electronic horn includes a cover (8) on a front side of an intermediate element (6). A first passage (P1) within the horn is defined by a central portion (82) of the cover (8) that projects into a cylindrical interior of a cylindrical water-proofing wall (621). Second passages (P2, P3, P4) extend generally concentrically with respect to the first passage (P1) and are respectively defined by water-proofing walls (83, 84) that are formed on the cover (8) and project into the interior spaces of water-proofing walls (622, 633). The outermost second passage (P4) opens toward the forward direction. The first and second passages (P1-P4) extend in a back-and-forth path that prevents any rainwater, which has entered the interior of the horn through the opening of the outermost second passage (P4), from reaching a resonance space (7) defined between the resonator (7) and a sound-generating oscillator (51).

Abstract: An electronic horn for use, e.g., in a vehicle, includes a piezoelectric element (52) that excites a plate-shaped oscillator (51). A resonator (7) is provided with an opening (71) and covers forward of the oscillator such that a resonance space (S) is defined between the resonator and the oscillator. An inner cylinder (62) and an outer conical housing (63) are provided concentrically around the resonator. A circular cover (8) covers the inner cylinder (62) and the outer conical housing (63) from the front, such that a buffer chamber (BR), at least one first sound amplifying chamber (MH1), and a second sound amplifying chamber (MH2) are defined around an entire circumference of the opening of the resonator.

Abstract: An electronic horn includes a cover (8) on a front side of an intermediate element (6). A first passage (P1) within the horn is defined by a central portion (82) of the cover (8) that projects into a cylindrical interior of a cylindrical water-proofing wall (621). Second passages (P2, P3, P4) extend generally concentrically with respect to the first passage (P1) and are respectively defined by water-proofing walls (83, 84) that are formed on the cover (8) and project into the interior spaces of water-proofing walls (622, 633). The outermost second passage (P4) opens toward the forward direction. The first and second passages (P1-P4) extend in a back-and-forth path that prevents any rainwater, which has entered the interior of the horn through the opening of the outermost second passage (P4), from reaching a resonance space (7) defined between the resonator (7) and a sound-generating oscillator (51).

Abstract: An electronic vehicle horn outputs a warning sound by exciting a diaphragm using a piezoelectric device that is driven with a composite signal generated, in part, by modulating a first fundamental square wave with a first modulating square wave and setting a frequency deviation at the time of the modulation in a predetermined range, modulating a second fundamental square wave with a second modulating square wave and setting a frequency deviation at the time of the modulation in a predetermined range, and generating the composite signal by mixing the modulated first fundamental square wave and the modulated second fundamental square wave.

Abstract: An electronic vehicle horn outputs a warning sound by exciting a diaphragm using a piezoelectric device that is driven with a composite signal generated, in part, by modulating a first fundamental square wave with a first modulating square wave and setting a frequency deviation at the time of the modulation in a predetermined range, modulating a second fundamental square wave with a second modulating square wave and setting a frequency deviation at the time of the modulation in a predetermined range, and generating the composite signal by mixing the modulated first fundamental square wave and the modulated second fundamental square wave.

Abstract: An object is to enhance workability in attachment in a sound generating apparatus that generates sound by vibrating a vibration plate with a vibrator while ensuring acoustic performance as good as that achieved by fastening with fine screw threads. Workability in attaching operation is improved while ensuring acoustic performance as good as that provided by fastening with fine screw threads, by providing first fixing portion that brings engagement portions into screw engagement with each other by rotation by a predetermined angle that can be attained by a user without taking his/her hand that holds a coupler off it and second fixing portion for fixing the coupler to a bracket so as to prevent the coupler from rotating relative to said bracket in a direction to loosen the engagement achieved by said first fixing portion.

Abstract: An object is to enhance workability in attachment in a sound generating apparatus that generates sound by vibrating a vibration plate with a vibrator while ensuring acoustic performance as good as that achieved by fastening with fine screw threads. Workability in attaching operation is improved while ensuring acoustic performance as good as that provided by fastening with fine screw threads, by providing first fixing portion that brings engagement portions into screw engagement with each other by rotation by a predetermined angle that can be attained by a user without taking his/her hand that holds a coupler off it and second fixing portion for fixing the coupler to a bracket so as to prevent the coupler from rotating relative to said bracket in a direction to loosen the engagement achieved by said first fixing portion.

Abstract: An object is to enhance workability in attachment in a sound generating apparatus that generates sound by vibrating a vibration plate with a vibrator while ensuring acoustic performance as good as that achieved by fastening with fine screw threads. Workability in attaching operation is improved while ensuring acoustic performance as good as that provided by fastening with fine screw threads, by providing first fixing means that brings engagement portions 31 and 41 into screw engagement with each other by rotation by a predetermined angle that can be attained by a user without taking his/her hand that holds a coupler 3 off it and second fixing means for fixing the coupler 3 to a bracket 4 so as to prevent the coupler 3 from rotating relative to said bracket 4 in a direction to loosen the engagement achieved by said first fixing means.

Abstract: A discharge lamp ballast circuit has a snubber circuit to perform a soft switching when the MOS transistor is turned off. The snubber circuit has, for example, a capacitor that resonates with a reactance of the fly-back transformer and enables a zero voltage switching. Before a breakdown of a discharge lamp, a control circuit drives the MOS transistor in a non-zero voltage switching manner by turning on the MOS transistor just after a peak voltage. The non-zero voltage switching increases an output voltage of the fly-back transformer. After the breakdown of the discharge lamp, the control circuit turns on the MOS transistor in the zero voltage switching manner to perform the soft switching. As a result, it is possible to reduce switching loss during a lighting of the discharge lamp and to supply sufficient voltage in the lighting preparation period.

Abstract: In a discharge lamp apparatus, a casing of an electronic controller unit for a discharge lamp is comprised of a resin casing and a metal casing and accommodates therein circuit components for generating a voltage supplied to the discharge lamp. The resin casing couples with and contacts with the connector part of the discharge lamp. A power MOS transistor is attached to the metal casing through a plate member made of an insulating material. With this arrangement, heat generated by the discharge lamp is less likely to transfer from the resin casing to the metal casing, and heat generated by the power MOS transistor is efficiently radiated from the metal casing to the outside.

Abstract: A discharge lamp driver circuit is provided which features a field canceller. The driver circuit includes a power supply circuit which turns on and off a switching element to step up a dc voltage and provide it for turning on a discharge lamp. The power supply circuit includes an electrical path through which an interrupted current arising from the on-off operation of the switching element flows. The field canceller includes an electric line through which the interrupted current having passed through the electrical path flows in an opposite direction, thereby producing a field canceling a field caused by flow of the interrupted current through the electrical path.

Abstract: In a headlamp for a vehicle, a lighting control circuit unit is provided in a lamp housing. The lighting control circuit unit is fixed to a holder with screws and the holder is fixed to a rear surface of a reflector with screws. A discharge lamp bulb is held on the reflector. The discharge lamp bulb is directly connected to the lighting control circuit unit. The lighting control circuit unit is removable through an opening of the lamp housing in a state that the discharge lamp bulb is held on the reflector. Also, the discharge lamp bulb is exchangeable through the opening.

Abstract: An AC power generating apparatus for lighting a discharge lamp has a smoothing circuit with an electrolytic capacitor therein for smoothing ripples included in a DC voltage supplied from a power source. The apparatus further has a switching device and a transformer for transforming a smoothed voltage by turning on and off application of the smoothed voltage to the transformer thereby to supply AC electric power for activating a discharge lamp. A capacitor is connected in parallel with the electrolytic capacitor. This parallel capacitor is located inside an area surrounded by the transformer, the switching device and the electrolytic capacitor to reduce a circuit area where electromagnetic radiation noise is generated.

Abstract: Providing a discharge lamp device to reduce noise radiation and to reduce a surge pulse current resulting from a shield sheath involves providing a ballast, including a DC/DC conversion circuit for boosting a direct current voltage from a battery, an inverter circuit for converting the voltage boosted by the DC/DC conversion circuit into an alternating current voltage, a starting circuit having a second transformer for boosting to such a voltage that causes a breakdown between electrodes of a lamp in starting up the lamp, and a metal case for accommodating the DC/DC conversion circuit, the inverter circuit, and the starting circuit. A secondary winding of the second transformer of the starting circuit is connected between the lamp and the inverter circuit connected to the lamp. An electrode member is interposed between the second transformer and the metal case.

Abstract: A discharge lamp driver circuit is provided which features a field canceller. The driver circuit includes a power supply circuit which turns on and off a switching element to step up a dc voltage and provide it for turning on a discharge lamp. The power supply circuit includes an electrical path through which an interrupted current arising from the on-off operation of the switching element flows. The field canceller includes an electric line through which the interrupted current having passed through the electrical path flows in an opposite direction, thereby producing a field canceling a field caused by flow of the interrupted current through the electrical path.

Abstract: Providing a discharge lamp device to reduce noise radiation and to reduce a surge pulse current resulting from a shield sheath involves providing a ballast, including a DC/DC conversion circuit for boosting a direct current voltage from a battery, an inverter circuit for converting the voltage boosted by the DC/DC conversion circuit into an alternating current voltage, a starting circuit having a second transformer for boosting to such a voltage that causes a breakdown between electrodes of a lamp in starting up the lamp, and a metal case for accommodating the DC/DC conversion circuit, the inverter circuit, and the starting circuit. A secondary winding of the second transformer of the starting circuit is connected between the lamp and the inverter circuit connected to the lamp. An electrode member is interposed between the second transformer and the metal case.

Abstract: A discharge lamp ballast circuit has a snubber circuit to perform a soft switching when the MOS transistor is turned off. The snubber circuit has, for example, a capacitor that resonates with a reactance of the fly-back transformer and enables a zero voltage switching. Before a breakdown of a discharge lamp, a control circuit drives the MOS transistor in a non-zero voltage switching manner by turning on the MOS transistor just after a peak voltage. The non-zero voltage switching increases an output voltage of the fly-back transformer. After the breakdown of the discharge lamp, the control circuit turns on the MOS transistor in the zero voltage switching manner to perform the soft switching. As a result, it is possible to reduce switching loss during a lighting of the discharge lamp and to supply sufficient voltage in the lighting preparation period.

Abstract: An AC power generating apparatus for lighting a discharge lamp has a smoothing circuit with an electrolytic capacitor therein for smoothing ripples included in a DC voltage supplied from a power source. The apparatus further has a switching device and a transformer for transforming a smoothed voltage by turning on and off application of the smoothed voltage to the transformer thereby to supply AC electric power for activating a discharge lamp. A capacitor is connected in parallel with the electrolytic capacitor. This parallel capacitor is located inside an area surrounded by the transformer, the switching device and the electrolytic capacitor to reduce a circuit area where electromagnetic radiation noise is generated.

Abstract: In a headlamp for a vehicle, a lighting control circuit unit is provided in a lamp housing. The lighting control circuit unit is fixed to a holder with screws and the holder is fixed to a rear surface of a reflector with screws. A discharge lamp bulb is held on the reflector. The discharge lamp bulb is directly connected to the lighting control circuit unit. The lighting control circuit unit is removable through an opening of the lamp housing in a state that the discharge lamp bulb is held on the reflector. Also, the discharge lamp bulb is exchangeable through the opening.