Abstract: An electrostatic type ultrasonic transducer of a push-pull system is constructed such that a through hole is arranged in the central portion of a fixing electrode of a circular shape. A sound wave reflecting plate is arranged on the rear face of the ultrasonic transducer and an ultrasonic wave radiated from the rear face of the ultrasonic transducer is reflected by the sound wave reflecting plate and is radiated to the front face of the ultrasonic transducer through the through hole.

Abstract: An electrostatic ultrasonic transducer includes a first electrode having a through hole, a second electrode having a through hole, and an oscillation film disposed such that the through hole of the first electrode can be paired with the through hole of the second electrode and sandwiched between the pair of the first electrode and second electrode. The oscillation film has an electrode layer to which direct current bias voltage is applied. Each of the pair of the electrodes has an electrode portion at a position in the periphery of the through hole. An alternating current signal is applied between the pair of the electrodes and the electrode layer of the oscillation film.

Abstract: A projector having an ultrasonic speaker including an ultrasonic transducer for emitting an ultrasonic wave signal to a screen; a distance measuring device for measuring a distance between the ultrasonic transducer and the screen; and an ultrasonic frequency control device for controlling a frequency of the ultrasonic wave signal based on a measured result of the distance measuring device and a sound pressure of the ultrasonic wave signal emitted by the ultrasonic transducer, so that the ultrasonic wave signal has a predetermined sound pressure at or in a vicinity of the screen. The projector may include a storage device for storing a propagation loss characteristic in air of the ultrasonic wave signal emitted from the ultrasonic transducer. The ultrasonic frequency control device controls the frequency of the ultrasonic wave signal by referring to the propagation loss characteristic of the ultrasonic wave signal stored in the storage device.

Abstract: An ultrasonic transducer includes: a fixed electrode having corrugations on the surface; a vibrating film having an electrode layer and disposed on the surface of the fixed electrode; and a holding member which holds the fixed electrode and the vibrating film. The ultrasonic transducer is driven by applying an AC signal between the electrode layer of the vibrating film and the fixed electrode, and generates a sound pressure of at least 120 dB within a frequency range from 20 kHz to 120 kHz.

Abstract: A superdirectional acoustic system for reproducing a sound signal supplied from a real sound source by using a superdirectional speaker and producing a virtual sound source in a vicinity of a sound wave reflection surface. The system includes an ultrasonic speaker, which includes an ultrasonic transducer for oscillating a sound wave in an ultrasonic frequency band, for reproducing an audio signal in a relatively medium to high frequency sound range, which is included in the sound signal supplied from the real sound source; and a low frequency sound reproducing speaker for reproducing an audio signal in a relatively low frequency sound range, which is included in the sound signal supplied from the real sound source. Sound in the medium-high frequency range is reproduced in a manner such that the sound is produced from a virtual sound source which is formed in the vicinity of the sound signal reflection surface such as a screen.

Abstract: An ultrasonic transducer includes: a pair of fixed electrodes including a conductive member; a vibrating film having a conductive layer; and a member which holds the pair of fixed electrodes and the vibrating film. The vibrating film is formed of nonconductive bodies and has an electrode layer formed of a conductive material. The electrode layer is applied with a DC bias voltage of a single polarity by a DC bias supply, and is also applied with an AC signal output from a signal source superimposed on the DC bias voltage. The pair of fixed electrodes have a plurality of holes of the same number at positions facing each other via the vibrating film, and an AC signal is applied between the conductive members of the pair of fixed electrodes by the signal source.

Abstract: An electrostatic ultrasonic transducer includes a first electrode that has through-holes, a second electrode that has through-holes, and a vibrating membrane that is disposed such that the through-holes of the first electrode and the through-holes of the second electrode form a pair, interposed between a pair of electrodes composed of the first electrode and the second electrode, and having a conductive layer applied with a direct current bias voltage. The first electrode and the second electrode each have counter electrode portions that are formed in the through-holes to face the vibrating membrane, and a modulated wave, which is obtained by modulating a carrier wave in an ultrasonic frequency band with a signal wave in an audible frequency band, is applied between the pair of electrodes.

Abstract: A Push-Pull-type electrostatic ultrasonic transducer includes a first electrode having a through hole, a second electrode having a through hole making a pair with the through hole of the first electrode, and a vibration film held between a pair of electrodes composed of the first and the second electrodes and having a conductive layer to which a direct-current bias voltage is applied, and holds the pair of electrodes and the vibration film.

Abstract: A push-pull-type electrostatic-type ultrasonic transducer includes a first electrode having through holes, a second electrode having through holes each of which is paired with the corresponding through hole of the first electrode, and an oscillation film sandwiched between a pair of the first and second electrodes and having a conductive layer to which direct current bias voltage is applied. When a wavelength obtained from a resonance frequency at a mechanical oscillation resonance point of the oscillation film is ?, a thickness t of the respective fixed electrodes is (?/4)·n or substantially (?/4)·n (where ?: wavelength of ultrasonic wave, n: positive odd number). AC signals as modulation waves produced by modulating carrier waves in an ultrasonic frequency band by signal waves in an audio frequency band are applied between a pair of the electrodes.

Abstract: The present invention relates to an ultrasonic transducer that has a diaphragm in which an electrode layer is formed thereon. A fixed electrode having a plurality of asperities on the surface facing the diaphragm is provided. An alternating current signal is applied between the electrode layer formed on the diaphragm and the fixed electrode to generate ultrasonic waves. A groove is formed on the upper surface of the projections of the asperities of the fixed electrode to prevent the diaphragm from sticking to the fixed electrode.

Abstract: A projector including an ultrasonic speaker that includes an ultrasonic transducer capable of oscillating an acoustic signal in a wide frequency band and reproduces signal sound in the audio frequency band, and a projector main body that includes a projecting optical system that projects a video image on a projecting surface. The ultrasonic speaker and the projector main body are integrated with each other.

Abstract: An electrostatic ultrasonic transducer includes: a first electrode provided with a through hole; a second electrode provided with a through hole forming a pair with the through hole of the first electrode wherein an alternating current signal is applied between the first electrode and the second electrode; an oscillation film sandwiched between the pair of electrodes and having a conductive layer wherein a direct current bias voltage is applied to the conductive layer; and a holding member for holding the pair of electrodes and the oscillation film, wherein a value “a” of one side amplitude of the film oscillation is obtained by the following formula: a=(1/?f)?{(Io·10P/10)/2?oc} wherein Io denotes the reference acoustic intensity, the reference acoustic intensity being 0.96×10?12 (W/m2), ?o is the density of the air, the density of the air being 1.

Abstract: A structure including an ultrasonic transducer, a material database, and a material determination section. The ultrasonic transducer transmits ultrasound signals of a plurality of frequencies toward a printing paper over a frequency band covering 40 kHz to 100 kHz or more, and receives reflection signals. The material database stores information representing a reception signal on a material basis. The material determination section makes a material determination for the printing paper based on the information stored in the material database, and the signal (signal derived by amplifying a signal) received by the ultrasonic transducer.

Abstract: An electrostatic ultrasonic transducer that includes: a first electrode that is formed with a plurality of holes; a second electrode that is formed with a plurality of holes, and is used in pair with the first electrode; an oscillation film formed with a conductor layer that is sandwiched between the pair of electrodes, and the conductor layer is applied with a direct-current (DC) bias voltage; and a retention member that keeps hold of the pair of electrodes and the oscillation film. In the transducer, an alternating signal is applied between the pair of electrodes, and the pair of electrodes each have a thickness t of about (?/4)·n (where k denotes a wavelength of ultrasound, and n denotes a positive odd number).

Abstract: An electrostatic type ultrasonic transducer of a push-pull system is constructed such that a through hole is arranged in the central portion of a fixing electrode of a circular shape. A sound wave reflecting plate is arranged on the rear face of the ultrasonic transducer and an ultrasonic wave radiated from the rear face of the ultrasonic transducer is reflected by the sound wave reflecting plate and is radiated to the front face of the ultrasonic transducer through the through hole.

Abstract: A projector including an ultrasonic speaker that includes an ultrasonic transducer capable of oscillating an acoustic signal in a wide frequency band and reproduces signal sound in the audio frequency band, and a projector main body that includes a projecting optical system that projects a video image on a projecting surface. The ultrasonic speaker and the projector main body are integrated with each other.

Abstract: An ultrasonic speaker including: a vibration film having a conductive layer; a pair of fixed electrodes provided oppositely to respective surfaces of the vibration film; and an ultrasonic transducer that causes the vibration film to generate sound waves by applying a DC bias voltage to the conductive layer of the vibration film while applying an alternating signal between the pair of fixed electrodes, and outputs the sound waves generated by the vibration film from two sound wave output surfaces via through-holes provided in each of the pair of fixed electrodes. The two sound wave output surfaces of the ultrasonic transducer are disposed in a direction intersecting with a sound wave emitting direction at right angles. Also, sound wave reflection plates are provided to both of the two sound wave output surfaces of the ultrasonic transducer so that the sound waves outputted from each of the two sound wave output surfaces are reflected in the sound wave emitting direction.

Abstract: The present invention relates to an ultrasonic transducer that has a diaphragm in which an electrode layer is formed thereon. A fixed electrode having a plurality of asperities on the surface facing the diaphragm is provided. An alternating current signal is applied between the electrode layer formed on the diaphragm and the fixed electrode to generate ultrasonic waves. A groove is formed on the upper surface of the projections of the asperities of the fixed electrode to prevent the diaphragm from sticking to the fixed electrode.

Abstract: A structure including an ultrasonic transducer, a material database, and a material determination section. The ultrasonic transducer transmits ultrasound signals of a plurality of frequencies toward a printing paper over a frequency band covering 40 kHz to 100 kHz or more, and receives reflection signals. The material database stores information representing a reception signal on a material basis. The material determination section makes a material determination for the printing paper based on the information stored in the material database, and the signal (signal derived by amplifying a signal) received by the ultrasonic transducer.

Abstract: Protrusions (260) for adjusting the cogging torque of a rotor (21) are formed on a stator (22) in a small-size power generator (20). Since the protrusions (260) are formed on an inner periphery of a rotor accommodation hole (230) within an angular range of ±45° around a magnetic flux direction of a first magnetic circuit (100) having a smaller magnetic reluctance at a rotation center of the rotor (21), the cogging torque can be effectively reduced. Accordingly, even when the size of components such as an oscillating weight and a power spring is reduced for making a thin timepiece, rotation startability of the rotor can be improved, thus improving power generation efficiency of the small-size power generator.