ELECTRET AND ELECTROSTATIC INDUCTION CONVERSION DEVICE

摘要

To provide an electret having a high surface charge density, and an electrostatic induction conversion device comprising such an electret. An electret comprising a laminate wherein a layer (A) containing a polymer compound (a) having a relative dielectric constant of from 1.8 to 3.0 and a layer (B) containing a polymer compound (b) or inorganic substance (c) having a relative dielectric constant higher than the polymer compound (a) are directly laminated, wherein the difference between the relative dielectric constant of the polymer compound (b) or inorganic substance (c) and the relative dielectric constant of the polymer compound (a) is at least 0.3; the layer (A) is disposed on the outermost surface on a side opposite to the side where electric charge is injected at the time of injecting electric charge into the laminate to form the electret; and the layer (B) has a thickness of at least 1 µm.