摘要 |
An electret material is formed by the method which includes the step of passing a pair of electrical conductor elements along the surface of a dielectric material heated to a predetermined temperature. The conductor elements are supported between a pair of support members driven in a direction to move the conductor elements along the surface of the dielectric material for applying an electrical field to the material. A heating element positioned adjacent the surface of the dielectric material and movable with the conductor element heats an area of the dielectric material located between the conductor elements enabling the material to be polarized by the electrical field, thereby producing an electret. |