Abstract: A vibration device includes a bimorph type piezoelectric element having a first main surface and a second main surface facing each other and a vibration member bonded to the second main surface of the piezoelectric element. The piezoelectric element has a first active region disposed closer to the first main surface between the first and second main surfaces and a second active region disposed closer to the second main surface than the first active region between the first and second main surfaces. When a force generated in the first active region is F1, a force generated in the second active region is F2, and a force by which the vibration member restrains the second active region is Fr, F2?F1?Fr is satisfied.

Abstract: A piezoelectric element includes a piezoelectric body, an electrode layer, and a reinforcing layer. The piezoelectric body has a first main surface, a second main surface, and a side surface. The first main surface and the second main surface oppose each other. The side surface extends in an opposing direction in which the first main surface and the second main surface oppose each other in such a way as to connect the first main surface and the second main surface. The electrode layer is provided in the piezoelectric body. The reinforcing layer is provided on the first main surface. The electrode layer is provided opposing the first main surface and apart from the side surface. When viewed from the opposing direction, the electrode layer has a corner. When viewed from the opposing direction, the reinforcing layer overlaps the corner.

Abstract: A vibration device includes a piezoelectric vibrator having a piezoelectric element and a diaphragm having a pair of main surfaces facing each other, the piezoelectric element being bonded to the main surface, a vibration member where the piezoelectric vibrator is disposed, and an adhesive member disposed between the diaphragm and the vibration member and bonding the diaphragm and the vibration member. Each of the pair of main surfaces of the diaphragm has a rectangular shape when viewed from a facing direction of the pair of main surfaces, and the adhesive member is disposed in a facing manner on at least a pair of sides of the main surfaces.

Abstract: In a piezoelectric element, shift of a resonance point to a low-pitched sound side is achieved. A resonance point of a piezoelectric element moves to a low-pitched sound side when an active region is configured to be surrounded by an inactive region as in the configuration of the piezoelectric element. According to the piezoelectric element whose resonance point is moved to a low-pitched sound side, the piezoelectric element can realize a sound pressure that is sufficiently high for practical use when it is applied to an acoustic device.

Abstract: An acoustic device includes a piezoelectric element, an attachment member to which the piezoelectric element is attached, and a spacer. The piezoelectric element includes first and second principal surfaces opposing each other. The attachment opposes the first principal surface. The spacer is disposed between the piezoelectric element and the attachment member in such a manner as to form an acoustic space between the piezoelectric element and the attachment member. The spacer includes an adhesive layer including a principal surface in contact with the first principal surface and a principal surface in contact with the attachment member.

Abstract: An audio device includes a vibration member, and a first piezoelectric vibrator and a second piezoelectric vibrator that are provided on the vibration member. A natural frequency of the first piezoelectric vibrator is larger than a natural frequency of the second piezoelectric vibrator.

Abstract: A vibration device includes a piezoelectric vibrator having a piezoelectric element and a diaphragm having a pair of main surfaces facing each other, the piezoelectric element being bonded to the main surface, a vibration member where the piezoelectric vibrator is disposed, and an adhesive member disposed between the diaphragm and the vibration member and bonding the diaphragm and the vibration member. Each of the pair of main surfaces of the diaphragm has a rectangular shape when viewed from a facing direction of the pair of main surfaces, and the adhesive member is disposed in a facing manner on at least a pair of sides of the main surfaces.

Abstract: A vibration device includes a bimorph type piezoelectric element having a first main surface and a second main surface facing each other and a vibration member bonded to the second main surface of the piezoelectric element. The piezoelectric element has a first active region disposed closer to the first main surface between the first and second main surfaces and a second active region disposed closer to the second main surface than the first active region between the first and second main surfaces. When a force generated in the first active region is F1, a force generated in the second active region is F2, and a force by which the vibration member restrains the second active region is Fr, F2?F1?Fr is satisfied.

Abstract: An acoustic device includes a piezoelectric element, an attachment member to which the piezoelectric element is attached, and a spacer. The piezoelectric element includes first and second principal surfaces opposing each other. The attachment opposes the first principal surface. The spacer is disposed between the piezoelectric element and the attachment member in such a manner as to form an acoustic space between the piezoelectric element and the attachment member. The spacer includes an adhesive layer including a principal surface in contact with the first principal surface and a principal surface in contact with the attachment member.

Abstract: A vibration device includes a piezoelectric element and an adhesive layer. The piezoelectric element includes a first principal surface and a second principal surface opposing each other. The adhesive layer is disposed on the first principal surface and is in contact with the first principal surface. A tensile strength of the adhesive layer is 10 N/cm or more and 48 N/cm or less.

Abstract: In a piezoelectric element, shift of a resonance point to a low-pitched sound side is achieved. A resonance point of a piezoelectric element moves to a low-pitched sound side when an active region is configured to be surrounded by an inactive region as in the configuration of the piezoelectric element. According to the piezoelectric element whose resonance point is moved to a low-pitched sound side, the piezoelectric element can realize a sound pressure that is sufficiently high for practical use when it is applied to an acoustic device.

Abstract: A piezoelectric element includes a piezoelectric body, an electrode layer, and a reinforcing layer. The piezoelectric body has a first main surface, a second main surface, and a side surface. The first main surface and the second main surface oppose each other. The side surface extends in an opposing direction in which the first main surface and the second main surface oppose each other in such a way as to connect the first main surface and the second main surface. The electrode layer is provided in the piezoelectric body. The reinforcing layer is provided on the first main surface. The electrode layer is provided opposing the first main surface and apart from the side surface. When viewed from the opposing direction, the electrode layer has a corner. When viewed from the opposing direction, the reinforcing layer overlaps the corner.

Abstract: An acceleration sensor capable of improving sensitivity is provided. In the acceleration sensor, although a solder fillet is formed in a lower end of a terminal electrode exposed from a covering portion, the covering portion suppresses the rise of the solder fillet. Due to this, the operation of the acceleration sensor is not easily limited by the solder fillet, and the acceleration sensor can generate electric charge which corresponds to a load more accurately. Therefore, the sensitivity of the acceleration sensor can be improved.

Abstract: A semiconductor ceramic composition including a compound represented by the following general formula (1) as a main component. (BavBixAyREw)m(TiuTMz)O3??(1) (wherein, A represents both elements of Na and K; RE is at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Gd, Dy and Er; and TM is at least one element selected from the group consisting of V, Nb and Ta.) 0.01?x?0.15??(2) x?y?0.3??(3) 0?(w+z)?0.01??(4) v+x+y+w=1??(5) u+z=1??(6) 0.950?m?1.050??(7) further, 0.001 mol to 0.055 mol of Ca is included and the ratio of Na/(Na+K) is 0.1 or more and less than 1.

Abstract: A composite piezoelectric ceramic includes a compact of crystal particles including at least one of potassium niobate (KNbO3) and sodium niobate (NaNbO3) and optionally further including lithium niobate (LiNbO3), and a layer containing barium titanate (BaTiO3) that is disposed on the surface of the compact while forming a heterojunction with the compact. A piezoelectric device includes the composite piezoelectric ceramic.

Abstract: A semiconductor ceramic composition represented by formula (1), (BavBixAyREw)m(TiuTMz)O3??(1), wherein, A represents at least one element selected from Na and K, RE represents at least one element selected from Y, La, Ce, Pr, Nd, Sm, Gd, Dy and Er; 0.750y?x?1.50y??(2), 0.007?y?0.125??(3), 0?(w+z)?0.010??(4), v+x+y+w=1??(5), u+z=1??(6), 0.950?m?1.050??(7), 0.001 to 0.055 mol of Ca is contained, and 0.0005 to 0.005 mol of at least one selected from Mg, Al, Fe, Co, Cu and Zn is contained.

Abstract: A semiconductor ceramic composition which is a BaTiO3 based semiconductor ceramic composition, wherein, part of Ba is replaced by at least A (at least one alkali metal element selected from Na and K), Bi and RE (at least one element selected from rare earth elements including Y), and part of Ti is replaced by at least TM (at least one element selected from the group including of V, Nb and Ta), the relationships of 0.7?{(the content of Bi)/(the content of A)}?1.43, 0.017?{(the content of Bi)+(the content of A)}?0.25, and 0<{(the content of RE)+(the content of TM)}?0.01 are satisfied when the total content of Ti and TM is set as 1 mol, the grain sizes have a maximum peak in a grain size distribution in a range of 1.1 ?m to 4.0 ?m or less, and the distribution frequency of the peak is 20% or more.

Abstract: A barium titanate based PTC thermistor ceramic composition without using Pb. Its Curie temperature is shifted to a temperature higher than 120° C. The PTC thermistor can readily turn semiconductive even if it is sintered in air. The resistivity at 25° C. is low and the variation rate of the resistivity at 25° C. with time is little. The PTC thermistor ceramic composition includes a sintered body having a barium titanate based compound represented by formula (1) as the main component, (Ba1-x-y-wBixAyREw)?(Ti1-zTMz)O3 (1), wherein, 1.02y?x?1.5y (2), 0.007?y?0.125 (3), 0?(w+z)?0.01 (4), 0.97???1.06 (5), and the sintered body contains Ca in a ratio of 0.01 mol or more and less than 0.05 mol relative to 1 mol of Ti site in terms of element.

Abstract: An acceleration sensor capable of improving sensitivity is provided. In the acceleration sensor, although a solder fillet is formed in a lower end of a terminal electrode exposed from a covering portion, the covering portion suppresses the rise of the solder fillet. Due to this, the operation of the acceleration sensor is not easily limited by the solder fillet, and the acceleration sensor can generate electric charge which corresponds to a load more accurately. Therefore, the sensitivity of the acceleration sensor can be improved.