JP2005223820A5 - - Google Patents

Claims (11)

An upper electrode including a vibration film formed of an insulator and a conductive film formed on the vibration film, and a lower electrode having a plurality of irregularities formed on a surface of the upper electrode facing the vibration film. And an ultrasonic transducer that generates an ultrasonic wave by applying an alternating signal between the upper electrode and the lower electrode, and bringing the upper electrode and the lower electrode into close contact with each other,
An ultrasonic transducer characterized in that a resonance tube unit in which a plurality of vent holes for forming a double-ended opening tube that resonates at a desired frequency is provided on a plate material is fixed on the surface of the upper electrode. An upper electrode including a vibration film formed of an insulator and a conductive film formed on the vibration film, and a lower electrode having a plurality of irregularities formed on a surface of the upper electrode facing the vibration film. The lower electrode is provided with a vent hole communicating with the outside from a plurality of cavities formed between the upper electrode and the lower electrode by bringing the upper electrode and the lower electrode into close contact with each other. An ultrasonic transducer that generates ultrasonic waves by applying an AC signal between electrodes,
An ultrasonic transducer characterized in that a resonance tube unit in which a plurality of vent holes for forming a double-ended opening tube that resonates at a desired frequency is provided on a plate material is fixed on the surface of the upper electrode. A lower electrode having a plurality of irregularities formed on both sides;
Two upper electrodes each including a vibrating film formed of an insulator and facing each other on both surfaces of the lower electrode; and a conductive film formed on the vibrating film,
A plurality of cavities are formed at the upper and lower ends of the lower electrode by closely contacting the two upper electrodes and the lower electrode, and a cavity formed at the upper end of the lower electrode among the plurality of cavities, An ultrasonic transducer in which air holes communicating with the cavity formed at the lower end of the lower electrode immediately below are formed,
An ultrasonic transducer characterized in that a resonance tube unit in which a plurality of vent holes for forming a double-end opening tube that resonates at a desired frequency is provided on a plate material is fixed on the surface of the two upper electrodes.   4. The ultrasonic transducer according to claim 1, wherein the resonance tube unit is formed of a material that does not absorb the ultrasonic wave having the desired frequency to resonate. 5.   The length in the depth direction of the vent hole formed in the resonance tube unit is an integral multiple of the half-wave length of the wavelength of the ultrasonic wave to resonate. The described ultrasonic transducer.   6. The surface shape of the resonance tube unit is formed in a concave shape so that the length of each resonance tube in the depth direction becomes shorter toward the center portion. The described ultrasonic transducer.   6. The surface shape of the resonance tube unit is formed in a convex shape so that the length in the depth direction of each resonance tube becomes longer toward the center portion. The described ultrasonic transducer.   The surface shape of the resonance tube unit is formed so as to be inclined so that the length in the depth direction of each resonance tube changes linearly from one end to the other end of the plate member. The ultrasonic transducer according to claim 4.   The ultrasonic transducer according to any one of 1 to 8, wherein a vent hole formed in the resonance tube unit is formed at a position corresponding to the concave portion formed in the lower electrode.   The ultrasonic transducer according to claim 1, wherein an open end correction gap is provided between the resonance tube unit and the upper electrode. An ultrasonic speaker comprising the ultrasonic transducer according to claim 1.