The present disclosure describes a strained dielectric material comprising at least one type of component containing a domain wall variant pattern, or superdomain structure, that is in phase-co-existence with, or in close phase proximity to, a paraelectric state achieved at zero electric field or over a finite range of non-zero electric field, wherein the at least one type of component comprises one or more of an in-plane sub-domain polarization component, a plane-normal sub-domain polarization component, or a solid solution of a ferroelectric.

A flexoelectric structure that includes a flexible ceramic electret portion containing a ceramic component, the flexible ceramic electret portion including a charge retaining ceramic portion and an internal electrode positioned at an internal location of the charge retaining ceramic portion; and a flexible member outside the flexible ceramic electret portion.

A clamping system and a method of clamping a work piece are disclosed. The clamping system has an electrostatic clamp and a high-impedance voltmeter (“HIV”). The electro-static clamp may include a platen and a plurality of electrodes embedded in the platen. In use, at least some of the embedded electrodes provide one side of a capacitor and a work piece provides another side of the capacitor in order to hold the work piece relative to the platen when at least some of the embedded electrodes are electrically charged. The HIV is electrically connected to at least some of the embedded electrodes.

A clamping system and a method of clamping a work piece are disclosed. The clamping system has an electrostatic clamp and a high-impedance voltmeter (“HIV”). The electro-static clamp may include a platen and a plurality of electrodes embedded in the platen. In use, at least some of the embedded electrodes provide one side of a capacitor and a work piece provides another side of the capacitor in order to hold the work piece relative to the platen when at least some of the embedded electrodes are electrically charged. The HIV is electrically connected to at least some of the embedded electrodes.

A vibration-driven energy harvesting element is formed by processing a substrate having a first Si layer and a second Si layer with an insulating layer in between. The vibration-driven energy harvesting element includes: a fixed electrode formed in the first Si layer; and a movable electrode formed in the second Si layer, opposed to the fixed electrode with a gap space formed in the insulating layer in between, and movable relative to the fixed electrode.

A capacitor includes a first metal layer disposed on a wafer or substrate, a first polarized dielectric layer above the first metal layer and comprising a plurality of electrets formed by aligning molecular dipoles throughout a three-dimensional surface area of a polarizable dielectric material during polarization by applying a momentary electric field of positive or negative polarity, a second metal layer disposed on the first polarized dielectric layer to electrically isolate the first polarized dielectric layer, and a second polarized dielectric layer above the second metal layer, the second polarized dielectric layer comprising a plurality of electrets formed by aligning molecular dipoles throughout a three-dimensional surface area of a polarizable dielectric material during polarization by applying a second momentary electric field of opposing polarity. A plurality of alternating polarized dielectric layers and metal layers may be arranged in series to form a stack, with an internal passivation layer disposed between each stack.

The present invention provides an electret sheet that exhibits excellent piezoelectricity even by light stress. The electret sheet of the invention is characterized by including a charged porous sheet, in which the electret sheet has a compressive elastic modulus of 80 to 300 MPa when compressively deformed at 25° C. and a 50% compression stress of 120 to 300 kPa at 25° C., and thus has the excellent piezoelectricity for light stress and exhibits the excellent piezoelectricity even by light stress (0.5 N or less) caused by a pulse wave or a breathing.

Filter media, such as electret-containing filtration media for filtering gas streams (e.g., air), are described herein. In some embodiments, the filter media may be designed to have desirable properties such as stable filtration efficiency over the lifetime of the filter media, increased normalized gamma, relatively low pressure drop (i.e. resistance), and/or relatively low basis weight. In certain embodiments, the filter media may be a composite of two or more types of fiber layers where each layer may be designed to enhance its function without substantially negatively impacting the performance of another layer of the media. For example, one layer of the media may be designed to have a relatively low basis weight and/or a relatively high air permeability, and another layer of the media may be designed to have stable filtration efficiency and/or a relatively high efficiency throughout the filter media's lifetime. The filter media described herein may be particularly well-suited for applications that involve filtering gas streams (e.g., face masks, cabin air filtration, vacuum filtration, room filtration, furnace filtration, respirator equipment, residential or industrial HVAC filtration, high-efficiency particulate arrestance (HEPA) filters, ultra-low particular air (ULPA) filters, medical equipment), though the media may also be used in other applications.

The present invention provides an electret sheet that has excellent durability against a pressing force that is repetitively applied, that is, excellent compression recovery properties, and can suppress stuffiness even when used by attaching it to the skin of a human body. The electret sheet of the present invention has an air permeability of 10 to 1,000 sec/100 mL. Thus, the electret sheet has excellent durability against a pressing force that is repetitively applied, that is, excellent compression recovery properties, and can suppress stuffiness even when used by attaching it to the skin of a human body.

This invention provides electrically conductive electret, electret-based direct-current power source and structural electret, with applications including the self-sensing of damage, stress and strain (including structural self-sensing) and electric powering (including structural self-powering). The electret is an electrically conductive material comprising mobile charge carriers (electrons, holes or ions), which exhibit a gradient in the carrier concertation along a line connecting the positive charge center and negative charge center in the electret. The carriers create an electric dipole. The material is electrically continuous along this line, which is along the path of least electrical resistance. The material exhibits microstructure comprising microscopic features that are positioned along said line and that interact with said carriers, with the interaction enhancing said dipole. The materials are preferably metals, carbons and their composites. The electret's electric field preferably ranges from 10′ V/m to 1 V/m. The electrical conductivity preferably ranges from 10.sup.3Ω.sup.−1.Math.m.sup.−1 to 10.sup.8Ω.sup.−1.Math.m.sup.−1.