Abstract: A piezoelectric element including a plurality of stacked piezoelectric sheets, wherein the stretching axis of a first piezoelectric sheet and the stretching axis of a second piezoelectric sheet of the plurality of piezoelectric sheets are oriented in different directions from each other. Preferably, the stretching axis of the first piezoelectric sheet and the stretching axis of the second piezoelectric sheet are intersected at an angle of 90 degrees.

Abstract: A piezoelectric speaker that includes an electrode formed on opposing main surfaces of a piezoelectric sheet having a predetermined stretching axis and made of a chiral polymer. The electrode is divided into four electrode portions by a plurality of dividing lines extending in a radiation direction. The four electrode portions are distributed along the outer peripheral portion except for the central portion of a vibration region. Voltage is applied to the respective four electrode portions in such a manner that electric field vectors generated in the thickness direction of the piezoelectric sheet direct in opposite directions between the adjacent ones of four sheet portions of the piezoelectric sheet to which voltage is applied by the electrode portions.

Abstract: A piezoelectric element including a plurality of stacked piezoelectric sheets, wherein the stretching axis of a first piezoelectric sheet and the stretching axis of a second piezoelectric sheet of the plurality of piezoelectric sheets are oriented in different directions from each other. Preferably, the stretching axis of the first piezoelectric sheet and the stretching axis of the second piezoelectric sheet are intersected at an angle of 90 degrees.

Abstract: A hybrid lens (3) has a structure in which a resin layer (2) composed of an ultraviolet curable resin is formed on the surface of a lens base material (1) composed of translucent ceramic. The lens base material (3) is composed of translucent ceramic containing as a main component an oxide with a perovskite structure represented by A{M,(B1, B2)}O3 (A is at least one selected from Ba, Sr and Ca, B1 is at least one selected from In, Y, Zn and Mg, B2 is at least one selected from Ta and Nb, and M is at least one selected from Ti, Zr, Hf and Sn) and at least Fe and Cu as sub-components. When the Fe content and Cu content in the translucent ceramic are x and y, respectively, 3x+y is 40 ppm by weight or less so that the hybrid lens (3) having excellent uniformity in optical properties and no crack defect can be obtained.

Abstract: A translucent ceramic having a high light transmittance is provided. It contains a perovskite compound having a composition represented by a general formula: (Ba1-s-tSrsCat)(MxB1yB2z)vOw (where M contains at least one of Sn, Zr and Hf, B1 represents at least one of Mg, Zn, Y and In, B2 represents at least one of Ta and Nb, each of conditions of 0?s?0.99, 0.01?t?0.45, x+y+z=1, 0<x?0.9, 1.00?z/y?2.40, and 0.97?v?1.05 is satisfied, and w represents a positive number for maintaining electrical neutrality) as a primary component. This translucent ceramic can be used as, for example, an objective lens (2) of an optical pickup (9) to provide advantages. In another aspect some of M is replaced by Ti.

Abstract: A translucent ceramic having a high light transmittance is provided. It contains a perovskite compound having a composition represented by a general formula: (Ba1-s-tSrsCat)(MxB1yB2z)vOw (where M contains at least one of Sn, Zr and Hf, B1 represents at least one of Mg, Zn, Y and In, B2 represents at least one of Ta and Nb, each of conditions of 0?s?0.99, 0.01?t?0.45, x+y+z=1, 0<x?0.9, 1.00?z/y?2.40, and 0.97?v?1.05 is satisfied, and w represents a positive number for maintaining electrical neutrality) as a primary component. This translucent ceramic can be used as, for example, an objective lens (2) of an optical pickup (9) to provide advantages. In another aspect some of M is replaced by Ti.

Abstract: A hybrid lens (3) has a structure in which a resin layer (2) composed of an ultraviolet curable resin is formed on the surface of a lens base material (1) composed of translucent ceramic. The lens base material (3) is composed of translucent ceramic containing as a main component an oxide with a perovskite structure represented by A{M,(B1, B2)}O3 (A is at least one selected from Ba, Sr and Ca, B1 is at least one selected from In, Y, Zn and Mg, B2 is at least one selected from Ta and Nb, and M is at least one selected from Ti, Zr, Hf and Sn) and at least Fe and Cu as sub-components. When the Fe content and Cu content in the translucent ceramic are x and y, respectively, 3x+y is 40 ppm by weight or less so that the hybrid lens (3) having excellent uniformity in optical properties and no crack defect can be obtained.