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.

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 method is provided for growing a fiber structure, where the method includes: obtaining a substrate, growing an array of pedestal fibers on the substrate, growing fibers on the pedestal fibers, and depositing a coating surrounding each of the fibers. In another aspect, a method of fabricating a fiber structure includes obtaining a substrate and growing a plurality of fibers on the substrate according to 1½D printing. In another aspect, a multilayer functional fiber is provided produced by, for instance, the above-noted methods.

Disclosed herein are self-powered and multi-modal sensing wearables. The smart wearables can comprise mechano-luminescence-optoelectronic materials, which can be used for self-powered sensing and energy harvesting.

The present invention provides: a piezoelectric substrate which includes a first piezoelectric body having an elongated shape and helically wound in one direction, and which does not include a core material, in which the first piezoelectric body includes a helical chiral polymer (A) having an optical activity; in which the length direction of the first piezoelectric body is substantially parallel to the main direction of orientation of the helical chiral polymer (A) included in the first piezoelectric body; and in which the first piezoelectric body has a degree of orientation F, as measured by X-ray diffraction according to the following Equation (a), within the range of 0.5 or more but less than 1.0:
degree of orientation F=(180°−α)/180°  (a)
(in which α represents the half-value width of the peak derived from the orientation).

The present invention provides: a piezoelectric substrate which includes a first piezoelectric body having an elongated shape and helically wound in one direction, and which does not include a core material, in which the first piezoelectric body includes a helical chiral polymer (A) having an optical activity; in which the length direction of the first piezoelectric body is substantially parallel to the main direction of orientation of the helical chiral polymer (A) included in the first piezoelectric body; and in which the first piezoelectric body has a degree of orientation F, as measured by X-ray diffraction according to the following Equation (a), within the range of 0.5 or more but less than 1.0:
degree of orientation F=(180°−α)/180°  (a)
(in which α represents the half-value width of the peak derived from the orientation).

Provided is a novel piezoelectric element that has a generally long linear shape and has excellent flexibility and bend resistance. The piezoelectric element includes a core wire which is a resin wire having at least one layer of metal foil helically wound therearound, an organic piezoelectric layer that coats the core wire, and a conductor layer that coats the organic piezoelectric layer. The metal foil and the conductor layer each function as an electrode having the organic piezoelectric layer interposed therebetween. The at least one layer of metal foil is helically wound around the resin wire with gaps, and the ratio of the gap to the helical pitch of the metal foil is 0.4% to 50%.

A human body detection device including line-shaped piezoelectric substrates respectively provided in each of a plurality of regions in a plate material intersecting a direction of pressure received from a human body, and provided such that an axial direction of each of the piezoelectric substrates runs along the plate material so as to detect pressure applied in a radial direction of the piezoelectric substrate, memory, and a processor coupled to the memory. The processor is configured to be capable of detecting an output signal from each of the piezoelectric substrates.

A piezoelectric adaptive mesh includes multiple piezoelectric fibers that include piezoelectric structures that can act as sensor and/or actuators to enhance a person's comfort. The piezoelectric structures communicate with a controller and/or a software processing system and may identify the position of a user and make adjustments through the actuators to increase user comfort by providing support, assistance, treatment, and/or temperature adjustment.

A piezoelectric device includes a first piezoelectric sensor having a first inner conductor, a first piezoelectric body, and a first outer conductor, a second piezoelectric sensor having a second inner conductor, a second piezoelectric body, and a second outer conductor, and a differential signal forming unit having a pair of differential input terminals. When an external force acts on the first piezoelectric body, the first piezoelectric sensor generates a first voltage, and the second piezoelectric sensor generates a second voltage having a voltage different in polarity from the first voltage. The first inner conductor is electrically connected to one differential input terminal. The second inner conductor is electrically connected to the other differential input terminal. The differential signal forming unit forms a differential signal based on a first signal input to the one differential input terminal and a second signal input to the other differential input terminal.