Abstract: A sheet blank for forming a collapsible field director structure comprises a sheet of nonconductive material having at least three panels thereon, one of the panels being a master panel and the other two panels being slave panels. Each panel is substantially rectangular in shape and has elongated upper and lower edges and two relatively shorter side edges. Each panel is connected to at least one adjacent panel along an elongated edge. A patch of adhesive material is disposed on: the first surface of a first one of the panels; and another patch of adhesive material is disposed on: the first surface on one of the other panels or the second surface of said first one of the panels. The slave panels are each foldable along an elongated edge thereof so that a surface of each of the slave panels is brought into confronting facial adjacency to and adhered against a surface of the master panel.

Abstract: A sheet blank for forming a collapsible field director structure comprises a sheet of nonconductive material having at least three panels thereon, one of the panels being a master panel and the other two panels being slave panels. Each panel is substantially rectangular in shape and has elongated upper and lower edges and two relatively shorter side edges. Each panel is connected to at least one adjacent panel along an elongated edge. A patch of adhesive material is disposed on: the first surface of a first one of the panels; and another patch of adhesive material is disposed on: the first surface on one of the other panels or the second surface of said first one of the panels. The slave panels are each foldable along an elongated edge thereof so that a surface of each of the slave panels is brought into confronting facial adjacency to and adhered against a surface of the master panel.

Abstract: A collapsible field director structure convertible from a collapsed to a deployed state includes at least one master vane and at least a first and a second slave vane. The master vane includes a conductive flap having at least one electrically conductive region thereon. The conductor flap is attached to the mounting flange for articulable movement with respect thereto. Each slave vane has at least one electrically conductive region thereon. The slave vanes are flexibly connected to the master vane along a respective line of flexure. The vanes are foldable against each other so that the field director structure, in the collapsed state, is able to exhibit a generally planar configuration.

Abstract: A reusable self-supporting field director structure for use in heating an article in a microwave oven is characterized by an integral array of rigid vanes extending radially outwardly from a central axis, the vanes being molded from an electrically non-conductive heat-resistant material. At least a portion of one major surface of each vane has an electrically conductive material embedded thereinto. The electrically non-conductive heat-resistant material is either a polymeric resin (with an optional reinforcing matrix) or paperboard material. A plurality of bracing members, each extending between the first major surface of one vane and the second major surface of an adjacent vane, may be integrally molded into the field director structure.

Abstract: A reusable self-supporting field director for use in heating an article in a microwave oven is characterized by a plurality of vanes, with each vane extending radially outwardly from a central axis. Each vane is angularly adjacent to two other vanes and is attached to each other at their inner ends. Each vane has a predetermined thickness dimension. Each vane each vane has a substrate formed from an electrically non-conductive material having a predetermined coefficient of thermal expansion, and an electrically conductive sheath having a predetermined coefficient of thermal expansion that is different from the coefficient of thermal expansion of the substrate. The sheath encases the substrate so that a portion of the first and second major surfaces and a portion of the first and second minor surfaces of each vane are covered by an electrically conductive material.

Abstract: A method of making a self-supporting field director structure for use in heating an article in a microwave oven comprises in any operative order, the steps of: folding a first and a second elongated vane blank along a central fold line to form at least two V-shaped vane doublets, wherein each vane doublet itself comprises a first and a second vane attached together at a vertex, a portion of each vane being electrically conductive, inserting each of the vane doublets into a slotted annular support member so that each vane in each vane doublet extends through an adjacent slot in the annular support member, and attaching the vane doublets at their vertices thereby to define a vane array.

Abstract: A self-supporting field director structure for use in heating an article in a microwave oven is characterized by a vane array comprising a plurality of V-shaped vane doublets, wherein each vane doublet itself comprises a first and a second vane. Each vane extends radially outwardly from the central axis. Each vane has a substrate formed from an electrically non-conductive material, with a portion of each vane being electrically conductive. A vane support structure is attached to the vane array.

Abstract: A self-supporting field director structure for use in heating an article in a microwave oven includes a plurality of vanes connected to a central support member. Each vane is formed from an electrically conductive metallic material. Each vane extends radially outwardly from a central axis, with the radially inner end of each vane being spaced a predetermined separation distance from the axis.

Abstract: A reusable self-supporting field director for use in heating an article in a microwave oven is characterized by a plurality of vanes, with each vane extending radially outwardly from a central axis. Each vane is angularly adjacent to two other vanes. Each vane has a substrate formed from an electrically non-conductive material, with a portion of the major surface of each vane having an electrically conductive material thereon. A vane support structure is attached to the vanes.

Abstract: A reusable self-supporting field director for use in heating an article in a microwave oven is characterized by a plurality of vanes, with each vane extending radially outwardly from a central axis. Each vane is angularly adjacent to two other vanes and is attached to each other at their inner ends. Each vane has a predetermined thickness dimension. Each vane each vane has a substrate formed from an electrically non-conductive material having a predetermined coefficient of thermal expansion, and an electrically conductive wrapper having a predetermined coefficient of thermal expansion that is different from the coefficient of thermal expansion of the substrate. The wrapper wraps the substrate so that a portion of the first and second major surfaces are covered and the radially outer end of each vane is wrapped by an electrically conductive material.

Abstract: A reusable self-supporting field director for use in heating an article in a microwave oven is characterized by a plurality of vanes, with each vane extending radially outwardly from a central axis. Each vane is angularly adjacent to two other vanes and is attached to each other at their inner ends. Each vane has a predetermined thickness dimension. Each vane is formed from a pair of electrically non-conductive outer laminae, each having a predetermined coefficient of thermal expansion, and an inner core formed of an electrically conductive material. The core has a predetermined coefficient of thermal expansion that is different from the coefficient of thermal expansion of the outer laminae. The inner core and the outer laminae are arranged in a laterally symmetric fashion with the inner core being completely enclosed within the non-conductive outer laminae so that thermal expansion effects due to heating are equalized across the thickness of each vane.

Abstract: A reusable self-supporting field director for use in heating an article in a microwave oven is characterized by a plurality of vanes, with each vane extending radially outwardly from a central axis. Each vane is angularly adjacent to two other vanes and is attached to each other at their inner ends. Each vane has a predetermined thickness dimension. Each vane is formed from an electrically non-conductive outer jacket having a predetermined coefficient of thermal expansion and an inner layer of an electrically conductive material having a predetermined coefficient of thermal expansion that is different from the coefficient of thermal expansion of the outer jacket. The inner layer and the outer jacket are arranged in a laterally symmetric fashion with the inner layer being substantially completely enclosed within the electrically non-conductive outer jacket, so that thermal expansion effects due to heating are equalized across the thickness of each vane.

Abstract: A reusable self-supporting field director for use in heating an article in a microwave oven is characterized by a plurality of vanes, with each vane extending radially outwardly from a central axis. Each vane is angularly adjacent to two other vanes and is attached to each other at their inner ends. Each vane has a predetermined thickness dimension. Each vane comprises a substrate formed from an electrically non-conductive material having a predetermined coefficient of thermal expansion and an electrically conductive wrapper having a predetermined coefficient of thermal expansion that is different from the coefficient of thermal expansion of the substrate. The wrapper wraps the substrate so that a portion of the first and second major surfaces are covered and the radially inner end of each vane is wrapped by an electrically conductive material.

Abstract: Random, melt-processible copolyimides are disclosed herein. These copolyimides are semicrystalline and exhibit recoverable (semi)crystallinity from their melts. Associated processes, which entail either solution polymerization or melt polymerization, for producing and fabricating these copolyimides into useful articles having a predetermined shape are also disclosed.

Abstract: Random, melt-processible copolyimides are disclosed herein. These copolyimides are semicrystalline and exhibit recoverable (semi)crystallinity from their melts. Associated processes, which entail either solution polymerization or melt polymerization, for producing and fabricating these copolyimides into useful articles having a predetermined shape are also disclosed.

Abstract: Random, melt-processible copolyimides are disclosed herein. These copolyimides are semicrystalline and exhibit recoverable (semi)crystallinity from their melts. Associated processes, which entail either solution polymerization or melt polymerization, for producing and fabricating these copolyimides into useful articles having a predetermined shape are also disclosed.