A piezoelectric substrate, comprising: a conductor cord that has a core material and a conductor disposed around the core material; and an elongated piezoelectric body that is disposed around the conductor cord in a spiral manner, unidirectionally along an axial direction of the conductor cord, wherein: the piezoelectric body comprises an optically active helical chiral polymer, a lengthwise direction of the piezoelectric body and a main orientation direction of the helical chiral polymer in the piezoelectric body are substantially parallel to each other, the piezoelectric body has an orientation degree F. of from 0.5 to less than 1.0, and the conductor cord satisfies Formula (b): ΔD.sub.max<t.sub.pmin, wherein ΔD.sub.max is a maximum value of a difference in height between a division A that is selected from plural divisions and a division B that is adjacent to the division A, and t.sub.pmin is a minimum thickness of the piezoelectric body.

A sensor electric wire that is not readily affected by external noise, and a sensor circuit that uses the same, including a first internal conductor covered by a piezoelectric material, a second internal conductor provided on the outside of the piezoelectric material, and an external shield conductor surrounding the first internal conductor and the second internal conductor, an insulating body being disposed between the first internal conductor and second internal conductor, and the external shield conductor.

A hydrophone may include a first piezoelectric cable including alternating sections of positive polarity and negative polarity, and a second piezoelectric cable including alternating sections of negative polarity and positive polarity. At least a portion of each section of positive polarity of the first piezoelectric cable may be bonded or adhered to at least a portion of a section of negative polarity of the second piezoelectric cable. A method of manufacturing a hydrophone may include winding or coiling a first piezoelectric cable and a second piezoelectric cable at the same time to create a series of wound sections including cables, the wound sections alternating with a series of not wound sections including the cables.

Sensing an environment by confining a monitored live subject in an enclosure, detecting an effect on a coaxial piezoelectric cable resulting from the monitored live subject, wherein the coaxial piezoelectric cable is located at least proximate to the enclosure, and deriving information about a state of the monitored live subject based on the detected effect.

The present invention relates to a piezoelectric fiber having excellent flexibility, the piezoelectric fiber employs a conductive fiber member as an inner electrode, on which a piezoelectric polymer layer, an outer electrode and a coating layer are sequentially formed, thereby having excellent flexibility and sufficient elasticity to be sewed, woven, knotted or braided. Therefore, the piezoelectric fiber can be applied in power supplies for a variety of sizes and types of wearable electronic devices, portable devices, clothing, etc. In addition, since the piezoelectric fiber has excellent piezoelectricity and durability because of the above-described structure, it can effectively convert deformation or vibration caused by external physical force into electric energy, and thus can replace existing ceramic-based and polymer piezoelectric bodies, etc. Furthermore, an economical and simple method of manufacturing a piezoelectric fiber having excellent piezoelectricity is provided.

Sensing an environment by confining a monitored live subject in an enclosure, detecting an effect on a coaxial piezoelectric cable resulting from the monitored live subject, wherein the coaxial piezoelectric cable is located at least proximate to the enclosure, and deriving information about a state of the monitored live subject based on the detected effect.

Sensing an environment by confining a monitored live subject in an enclosure, detecting an effect on a coaxial piezoelectric cable resulting from the monitored live subject, wherein the coaxial piezoelectric cable is located at least proximate to the enclosure, and deriving information about a state of the monitored live subject based on the detected effect.

A piezoelectric substrate attachment structure including a press section pressed by contact, a piezoelectric substrate provided adjacent to the press section, and a base section provided adjacent to the piezoelectric substrate on an opposite side from the press section. The following relationship Equation (a) is satisfied:

da/Ea<db/Eb(a) wherein da is a thickness of the press section in a direction of adjacency to the piezoelectric substrate, Ea is a storage modulus of the press section from dynamic viscoelastic analysis, db is a thickness of the base section in the adjacency direction, and Eb is a storage modulus of the base section from dynamic viscoelastic analysis.

Provided is a technique related to a new sensor unit which is flexible in that the sensor unit can be installed in various locations such as inside of a structure with a large curvature, and which can stably measure multi-directional deformation and very efficiently and wireless measure deformation information, and thus provided is a technique of a sensor structure which can be universally utilized in various systems for measuring deformation information. The sensor unit using an electro-active polymer for the wireless transmission/reception of deformation information, according to a first embodiment of the present invention, comprises: a first sensor part formed from a fiber or film comprising a ferroelectric electro-active polymer material; a second sensor part configured to include the first sensor part therein, and formed from a matrix comprising a dielectric elastomer electro-active polymer material; and an electrode part provided to come into contact with the first sensor part or the second sensor part and, when an external force is applied to the first sensor part or the second sensor part, transmits to the outside an electric signal generated by the first sensor part or the second sensor part.

A piezoelectric body that is excellent in endurance, flexibility and bendability is achieved. A piezoelectric member includes: belt type first and second conductive rubber sheets that face each other; and a piezoelectric layer formed between an upper surface of the first conductive rubber sheet and a lower surface of the second conductive rubber sheet. The piezoelectric layer is made of a piezoelectric coating material with which at least either one of the upper surface of the first conductive rubber sheet and the lower surface of the second conductive rubber sheet is coated. When a pressure is applied to the piezoelectric layer through at least either one of the first conductive rubber sheet and the second conductive rubber sheet, a potential difference is generated between the first conductive rubber sheet and the second conductive rubber sheet.