US Patent 7238404 Thin sheet mica wedges with semi-conducting properties

The present invention provides for thin sheet wedges that comprise a mica matrix impregnated with a conductive resin. The mica matrix is composed of mica flakes. The thin sheet wedge has a semi-conductive property of 500–500,000 ohms per square. In one embodiment the thin sheet wedge further comprises at least one glass fiber layer. In a particular embodiment the glass fiber layer is a backing for the mica matrix. In another particular embodiment the glass fiber is interwoven with the mica matrix. The glass fiber layer may itself be impregnated with a conductive resin.