Abstract: An electroacoustic transducer includes a piezoelectric speaker and a housing. The piezoelectric speaker has: a first vibration plate with a periphery; a piezoelectric element placed on at least one face of the first vibration plate; and multiple openings that are provided around the piezoelectric element and penetrate through the first vibration plate in its thickness direction that is a first axis direction. The housing has: a supporting part that directly or indirectly supports the periphery; and a sound introduction port that faces the piezoelectric speaker in the first axis direction. The sound introduction port is provided at a position where it does not overlap, in the first axis direction, a first opening having the largest open area among the multiple openings. The electroacoustic transducer can improve the acoustic characteristics of a piezoelectric speaker.

Abstract: A piezoelectric element which is a single-layer or laminated piezoelectric element has a first electrode, a second electrode, and a piezoelectric ceramic layer. The first electrode and second electrode contain silver by 50 percent by weight or more. The piezoelectric ceramic layer is placed between the first electrode and second electrode, and constituted by a polycrystalline substance of alkali niobate piezoelectric ceramic containing at least one alkali earth metal being calcium, strontium, or barium, and silver. According to this constitution, the electrical resistance and piezoelectric property can be improved, and consequently high reliability and good piezoelectric characteristics can be achieved.

Abstract: An electroacoustic transducer includes a dynamic speaker that generates a first acoustic sound, and a piezoelectric speaker that generates a second acoustic sound. The sum of the sound pressures of the first and second acoustic sounds in a crossover frequency range of the sound pressure of the first acoustic sound and the sound pressure of the second acoustic sound, is adjusted to be equal to or greater than 0.5 times the sound pressure of the first acoustic sound in the crossover frequency range so as to improve the acoustic properties in the crossover frequency range.

Abstract: A piezoelectric ceramic speaker includes a piezoelectric element using a vibration sheet formed with piezoelectric ceramic having a primary phase constituted by ceramic grains of perovskite crystal structure containing Pb, Nb, Zn, Ti, and Zr, and a secondary phase constituted by ZnO grains, wherein the primary phase is constituted by ceramic grains expressed by a composition formula Pb {(Zr(1-a)Tia)x·(Ni1/3Nb2/3)y·(Zn1/3Nb2/3)z}O3 (where 0<x?0.85, 0?y<1, 0<z<1, x+y+z=1, and 0.45?a?0.60); and an enclosure which encloses the piezoelectric element.

Abstract: An electroacoustic transducer that can improve acoustic characteristics has a housing and a piezoelectric speaker. The piezoelectric speaker has a first vibration plate with a periphery part supported directly or indirectly on the housing, as well as a piezoelectric element placed at least on one side of the first vibration plate, and is constituted in such a way that its rigidity is asymmetric with respect to the center axis of the first vibration plate.

Abstract: In an embodiment, a piezoelectric speaker 30 includes a sheet member 32 and multiple piezoelectric vibration parts 31. The multiple piezoelectric vibration parts 31 each have a vibration plate 311 supported on the sheet member 32 in a vibratable manner, as well as a piezoelectric element 312 joined to the vibration plate 311. In an embodiment, the piezoelectric speaker 30 in combination with a dynamic speaker 20 constitutes an electroacoustic transducer 104L/104R, and a pair of the electroacoustic transducers 104L, 104R constitute headphones 100. The piezoelectric speaker can improve sound pressures without lowering the resonance frequency.

Abstract: An electroacoustic transducer includes a dynamic speaker that generates a first acoustic sound, and a piezoelectric speaker that generates a second acoustic sound. The sum of the sound pressures of the first and second acoustic sounds in a crossover frequency range of the sound pressure of the first acoustic sound and the sound pressure of the second acoustic sound, is adjusted to be equal to or greater than 0.5 times the sound pressure of the first acoustic sound in the crossover frequency range so as to improve the acoustic properties in the crossover frequency range.

Abstract: An electroacoustic transducer includes: a polygonal-shaped laminated piezoelectric element including alternately stacked piezoelectric layers and electrode layers, with the piezoelectric layers placed between at least one pair of electrode layers having different polarities; and a circular vibration plate on which the laminated piezoelectric element is placed. Of the piezoelectric layers sandwiched between the at least one pair of electrode layers, the total volume (V) of those effective layers that overlap the at least one pair of electrode layers as viewed from the stacking direction satisfies the condition below: 0.2?R2×ts?V?2.0?R2×ts wherein ? represents the ratio of the circumference of a circle to its diameter, R represents the radius of the vibration plate, and ts represents the thickness of the vibration plate.

Abstract: An electroacoustic transducer includes a piezoelectric speaker and a housing. The piezoelectric speaker has: a first vibration plate with a periphery; a piezoelectric element placed on at least one face of the first vibration plate; and multiple openings that are provided around the piezoelectric element and penetrate through the first vibration plate in its thickness direction that is a first axis direction. The housing has: a supporting part that directly or indirectly supports the periphery; and a sound introduction port that faces the piezoelectric speaker in the first axis direction. The sound introduction port is provided at a position where it does not overlap, in the first axis direction, a first opening having the largest open area among the multiple openings. The electroacoustic transducer can improve the acoustic characteristics of a piezoelectric speaker.

Abstract: In an embodiment, a piezoelectric speaker 30 includes a sheet member 32 and multiple piezoelectric vibration parts 31. The multiple piezoelectric vibration parts 31 each have a vibration plate 311 supported on the sheet member 32 in a vibratable manner, as well as a piezoelectric element 312 joined to the vibration plate 311. In an embodiment, the piezoelectric speaker 30 in combination with a dynamic speaker 20 constitutes an electroacoustic transducer 104L/104R, and a pair of the electroacoustic transducers 104L, 104R constitute headphones 100. The piezoelectric speaker can improve sound pressures without lowering the resonance frequency.

Abstract: A piezoelectric speaker has a piezoelectric element and vibration plate. The piezoelectric element has a base body with a mounting surface, as well as first and second terminals that are formed on the mounting surface with a distance between them. The vibration plate has a conductive body joined to the piezoelectric element and having a principle surface facing the mounting surface, as well as a first hole with or without a bottom which is formed on the principle surface in a region facing the first terminal to form a space between the body and first terminal. The piezoelectric speaker is capable of preventing the external electrodes of the piezoelectric element from shorting to each other.

Abstract: An electroacoustic transducer that can improve acoustic characteristics has a housing and a piezoelectric speaker. The piezoelectric speaker has a first vibration plate with a periphery part supported directly or indirectly on the housing, as well as a piezoelectric element placed at least on one side of the first vibration plate, and is constituted in such a way that its rigidity is asymmetric with respect to the center axis of the first vibration plate.

Abstract: A piezoelectric ceramic speaker includes a piezoelectric element using a vibration sheet formed with piezoelectric ceramic having a primary phase constituted by ceramic grains of perovskite crystal structure containing Pb, Nb, Zn, Ti, and Zr, and a secondary phase constituted by ZnO grains, wherein the primary phase is constituted by ceramic grains expressed by a composition formula Pb {(Zr(1-a)Tia)x.(Ni1/3Nb2/3)y.(Zn1/3Nb2/3)z}O3 (where 0<x?0.85, 0?y<1, 0<z<1, x+y+z=1, and 0.45?a?0.60); and an enclosure which encloses the piezoelectric element.

Abstract: In an embodiment, an electroacoustic converter has an enclosure, piezoelectric sounding body, electromagnetic sounding body, passage, and wiring members. The piezoelectric sounding body includes a first vibration plate supported directly or indirectly on the enclosure, and a piezoelectric element placed at least on one side of the first vibration plate. The piezoelectric sounding body divides the interior of the enclosure into a first space and a second space. The electromagnetic sounding body has a second vibration plate and is placed in the first space. The passage is provided at the piezoelectric sounding body or around the piezoelectric sounding body, to connect the first space and second space. The wiring members are electrically connected to the piezoelectric element and led out toward the electromagnetic sounding body, from the piezoelectric element, through the first space or second space.

Abstract: A piezoelectric ceramic has a primary phase constituted by ceramic grains of perovskite crystal structure containing Pb, Nb, Zn, Ti, and Zr, and a secondary phase constituted by ZnO grains present sporadically in the primary phase. The piezoelectric ceramic of high kr and high specific dielectric constant can be sintered at low temperature and exhibit minimal characteristics variations.

Abstract: A piezoelectric element which is a single-layer or laminated piezoelectric element has a first electrode, a second electrode, and a piezoelectric ceramic layer. The first electrode and second electrode contain silver by 50 percent by weight or more. The piezoelectric ceramic layer is placed between the first electrode and second electrode, and constituted by a polycrystalline substance of alkali niobate piezoelectric ceramic containing at least one alkali earth metal being calcium, strontium, or barium, and silver. According to this constitution, the electrical resistance and piezoelectric property can be improved, and consequently high reliability and good piezoelectric characteristics can be achieved.

Abstract: A piezoelectric device has a piezoelectric ceramic layer obtained by sintering a piezoelectric ceramic composition that contains an alkali-containing niobate type perovskite composition which is represented by (LilNamK1-l-m)n(Nb1-oTao)O3 (wherein 0.04?l?0.1, 0?m?1, 0.95?n?1.05, 0?o?1) and Ag component, as well as a conductor layer sandwiching the piezoelectric ceramic layer. The piezoelectric ceramic layer has Ag segregated in voids present in a sintered compact of the perovskite composition in terms of oxides relative to the perovskite composition.

Abstract: In an embodiment, an electroacoustic converter (earphone 100) has an enclosure 41, piezoelectric sounding body 32, electromagnetic sounding body 31, and passage 35. The piezoelectric sounding body 32 includes a vibration plate 321 having a periphery supported directly or indirectly on the enclosure 41, and a piezoelectric element 322 placed at least on one side of the vibration plate 321. The piezoelectric sounding body 32 divides the interior of the enclosure 41 into a first space S1 and a second space S2. The electromagnetic sounding body 31 is placed in the first space S1. A passage 35 is provided in or around the piezoelectric sounding body 32, to connect the first space S1 and second space S2. The electroacoustic converter is capable of obtaining desired frequency characteristics easily.

Abstract: An electroacoustic transducer includes: a polygonal-shaped laminated piezoelectric element including alternately stacked piezoelectric layers and electrode layers, with the piezoelectric layers placed between at least one pair of electrode layers having different polarities; and a circular vibration plate on which the laminated piezoelectric element is placed. Of the piezoelectric layers sandwiched between the at least one pair of electrode layers, the total volume (V) of those effective layers that overlap the at least one pair of electrode layers as viewed from the stacking direction satisfies the condition below: 0.2?R2×ts?V?2.0?R2×ts wherein ? represents the ratio of the circumference of a circle to its diameter, R represents the radius of the vibration plate, and ts represents the thickness of the vibration plate.

Abstract: In an embodiment, an electroacoustic converter (earphone 100) has an enclosure 41, piezoelectric sounding body 32, electromagnetic sounding body 31, and passage 35. The piezoelectric sounding body 32 includes a first vibration plate 321 having a periphery supported directly or indirectly on the enclosure 41, and a piezoelectric element 322 placed at least on one side of the vibration plate 321. The piezoelectric sounding body 32 has a second vibration plate and divides the interior of the enclosure 41 into a first space S1 and a second space S2. The electromagnetic sounding body 31 is placed in the first space S1. The passage 35 is provided in or around the piezoelectric sounding body 32 to connect the first space S1 and second space S2. The electroacoustic converter is capable of obtaining desired frequency characteristics easily.