(under subclass 592.1) Process wherein the article made exhibits a permanent external electrostatic field due to internal polarization.
(1) Note. An electret possesses persistent electric polarization and is generally a solid dielectric. A few substances such as wax-resin electrets also exhibit piezoelectric properties. See the (1) Note to the definition of Class 29, subclass 25.35.
(2) Note. Some of the classes referred to in the search notes of Class 29, subclass 25.35, have a process that is useful in the manufacture of an electret.
(3) Note. This subclass is not limited to the manufacture of an electret by a metal working operation, but includes the manufacture of such a device by any type of operation where no other class provides for the entire subject matter claimed.
SEE OR SEARCH THIS CLASS, SUBCLASS:
25.35, for method of or apparatus for manufacturing a piezoelectric device or a piezoelectric material that is not classifiable in the specific classes relating to manufacturing.
610.1+, for a method of making a resistor under the class definition. 887, for a method of making an insulator under the class definition.
