Abstract: A method for producing a polymer piezoelectric film, comprising: a process of moving and stretching a crystalline polar polymer sheet in contact with a conductive stretching roller having a diameter of at least 30 mm and a surface friction coefficient which has been reduced to such a level as to allow a relative displacement of the crystalline polar polymer sheet in contact with the conductive stretching roller: and a step in the process of applying a polarization voltage between an electrode disposed opposite to the crystalline polar polymer sheet and the conductive stretching roller to polarize the crystalline polar polymer sheet. As a result, it is possible to stably produce a polymer piezoelectric film exhibiting stable piezoelectricity over a large area. Especially, it is possible to obtain polymer piezoelectric film exhibiting a temperature-dispersion peak temperature of d31 piezoelectricity coefficient at least 120° C. and surface scratches extending in one direction.

Abstract: An inexpensive piezoelectric sensor where noise unlikely occurs and a method for manufacturing the same are provided. A piezoelectric body (2) made of polymeric material, a first electrode-supporting portion (3) disposed at one side of the piezoelectric body (2) and supporting a signal electrode (3b) on a first insulator (3a), and a second electrode-supporting portion (4) disposed at the other side of the piezoelectric body (2) and supporting a ground electrode (4b) on a second insulator (4a) are included, and the first electrode-supporting portion (3) and the second electrode-supporting portion (4) are arranged so that the signal electrode (3b) and the ground electrode (4b) overlap each other in a layering direction.

Abstract: A piezoelectric film sensor includes a substrate 1 having a signal electrode 2 and a ground electrode 3 formed on the surface thereof, the substrate being folded to cause the signal electrode 2 and the ground electrode 3 to be overlapped with each other in a plane view, a piezoelectric film 5 inserted between the signal electrode 2 and the ground electrode 3 formed on the substrate 1 and a bonding layer 6 for bonding the folded substrate 1 thereby to affix the signal electrode 2, the ground electrode 3 and the piezoelectric film 5 together.

Abstract: A method for producing a polymer piezoelectric film, comprising: a process of moving and stretching a crystalline polar polymer sheet in contact with a conductive stretching roller having a diameter of at least 30 mm and a surface friction coefficient which has been reduced to such a level as to allow a relative displacement of the crystalline polar polymer sheet in contact with the conductive stretching roller: and a step in the process of applying a polarization voltage between an electrode disposed opposite to the crystalline polar polymer sheet and the conductive stretching roller to polarize the crystalline polar polymer sheet. As a result, it is possible to stably produce a polymer piezoelectric film exhibiting stable piezoelectricity over a large area. Especially, it is possible to obtain polymer piezoelectric film exhibiting a temperature-dispersion peak temperature of d31 piezoelectricity coefficient at least 120° C. and surface scratches extending in one direction.

Abstract: An inexpensive piezoelectric sensor where noise unlikely occurs and a method for manufacturing the same are provided. A piezoelectric body (2) made of polymeric material, a first electrode-supporting portion (3) disposed at one side of the piezoelectric body (2) and supporting a signal electrode (3b) on a first insulator (3a), and a second electrode-supporting portion (4) disposed at the other side of the piezoelectric body (2) and supporting a ground electrode (4b) on a second insulator (4a) are included, and the first electrode-supporting portion (3) and the second electrode-supporting portion (4) are arranged so that the signal electrode (3b) and the ground electrode (4b) overlap each other in a layering direction.

Abstract: A semiconductive polyvinylidene fluoride resin composition comprising 100 parts by weight of a polyvinylidene fluoride resin, 0.03 to 10 parts by weight of at least one tetraalkylammonium salt selected from the group consisting of tetraalkylammonium sulfates and tetraalkylammonium sulfites, and 1 to 20 parts by weight of conductive carbon black. A formed or molded product composed of the semiconductive polyvinylidene fluoride resin composition.

Abstract: A bone inducing material comprising a piezoelectric porous membrane having through-holes of an average pore size of about 0.1 to 5 .mu.m is disclosed. When the bone inducing material according to the present invention is used, bone is rapidly regenerated, and new formation of bone occurs. The bone inducing material is particularly useful in the dental field, for example, for treatment of periodontal diseases by GTR method.

Abstract: A generally tubular flexure sensor is constituted by winding a piezoelectric element including a polymeric piezoelectric strip provided with oppositely disposed surface electrode layers on both surfaces around a central axis (helical axis) so that the surface electrode layers are disposed substantially in parallel with an extension direction of the helical axis, and combining the helically wound piezoelectric element with a detection circuit for detecting a flexural deformation of the piezoelectric element in a direction perpendicular to the helical axis. The flexure sensor allows a large degree of flexural deformation in any direction to provides a good sensitivity and can be suitably used as a fish catch signal sensor for a fishing rod.

Abstract: A wave-receiving piezoelectric device for use as, e.g., a hydrophone or a microphone, is constituted by a piezoelectric body having two surfaces sandwiching a thickness and including at least one surface provided with a recess (including a perforation communicating with the two surfaces) set in the thickness direction, and a rigid member having a contact surface and an outer surface opposite to the contact surface and disposed to cover said at least one surface with the contact surface so as to make the recess airtight. As a result, an acoustic pressure received by the outer surface is concentrated and applied onto said at least one surface of the piezoelectric body, thereby giving an improved wave-receiving sensitivity at an enhanced acoustic pressure.

Abstract: A sheet-form piezoelectric device having improved mechanical strengths as represented by an electrode peel strength while retaining flexibility and piezoelectric performances of a polymer-type piezoelectric device, is obtained by embedding a perforated sheet electrode into at least one surface layer of a polymer piezoelectric film treated with a solvent in advance. The sheet-form piezoelectric device may be wound or curved about a certain central axis to provide a tubular or curved piezoelectric device having wave-transmitting and/or -receiving characteristics suitable for wave-transmitting and/or -receiving devices, such as a hydrophone and microphone.

Abstract: A polymer pyroelectric infrared sensor having an improved sensitivity and an improved heat resistance is formed by disposing a pyroelectric film having electrodes for taking out a pyroelectric output on both sides so as to face a window for introducing infrared rays. The pyroelectric film comprises a pyroelectric film of vinylidene fluoride copolymer having a crystallinity of 60% or more and a relative dielectric constant of 10 or below at 25.degree. C. and in a low frequency region of 0.1-10 Hz.

Abstract: Ultrafine fiber of an ethylene tetrafluoride copolymer having an orientation degree (.pi.) of at least 0.6 and an average fineness of 0.0001 to 0.9 denier. A process for producing such fiber or a porous membrane thereof is also disclosed.