Devices comprising conductive polymer compositions
First Claim
1. An electrical device which comprises(1) a resistive element composed of a first material which has a resistivity at 23°
- C. of 1 to 500,000 ohm.cm;
(2) a contact layer which is directly bonded to a surface of the resistive element, and is composed of a second conductive material having a resistivity at 23°
C. which is less than the resistivity at 23°
C. of the first material; and
(3) a further member which is composed of a third conductive material having a resistivity at 23°
C. which is less than the resistivity at 23°
C. of the second material, said further member being in direct physical contact with the contact layer and being maintained in such contact substantially only by means of pressure over a connection area which is at least 0.5 square inch in area or which has at least one dimension greater than 1 inch,the components of the device being positioned such that the device can be connected to a source of electrical power so that an electrical path exists from the further member to the resistive element, through the contact layer.
2 Assignments
0 Petitions
Accused Products
Abstract
A number of improvements to electrical devices, particularly sheet heaters, comprising conductive polymer compositions, are provided. The preferred heater has the following features (a) it comprises a laminar resistive element and a plurality of electrodes which are so positioned that the predominant direction of current flow is parallel to the faces of the laminar element, (b) it comprises a laminar insulating element adjacent to but not secured to the electrodes and the resistive element; (c) it comprises a metallic foil, which acts as a ground plane and is positioned adjacent the insulating element but is not secured thereto; (d) it comprises a dielectric layer intimately bonded to the resistive element and to the electrodes.
The invention also provides an electrical device comprising first and second members having different resistivities, and a thin contact layer of intermediate resistivity positioned between the first and second members.
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Citations
26 Claims
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1. An electrical device which comprises
(1) a resistive element composed of a first material which has a resistivity at 23° - C. of 1 to 500,000 ohm.cm;
(2) a contact layer which is directly bonded to a surface of the resistive element, and is composed of a second conductive material having a resistivity at 23°
C. which is less than the resistivity at 23°
C. of the first material; and(3) a further member which is composed of a third conductive material having a resistivity at 23°
C. which is less than the resistivity at 23°
C. of the second material, said further member being in direct physical contact with the contact layer and being maintained in such contact substantially only by means of pressure over a connection area which is at least 0.5 square inch in area or which has at least one dimension greater than 1 inch,the components of the device being positioned such that the device can be connected to a source of electrical power so that an electrical path exists from the further member to the resistive element, through the contact layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- C. of 1 to 500,000 ohm.cm;
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13. An electrical device which comprises
(1) a laminar resistive element which is composed of a first conductive material which has a resistivity at 23° - C. of 1 to 500,000 ohm.cm and which comprises spaced-apart substantially flat surfaces;
(2) a contact layer which is directly bonded to a flat surface of the resistive element, and is composed of a second conductive material having a resistivity at 23°
C. which is less than the resistivity at 23°
C. of the first material;(3) a further member which is composed of a third non-metallic conductive material having a resistivity at 23°
C. greater than 1×
10-5 ohm.cm but less than the resistivity at 23°
C. of the second material, the further member being in direct phsyical contact with the contact layer; and(4) a metal connection member which contacts the further member, the components of the device being positioned such that the device can be connected to a source of electrical power so that an electrical path exists from the further member to the resistive element, through the contact layer. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
- C. of 1 to 500,000 ohm.cm and which comprises spaced-apart substantially flat surfaces;
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24. An electrical device for use as a sheet heater which comprises
(1) a heating element comprising (a) a laminar resistive element which is composed of a first material which has a resistivity at 23° - C. of 1 to 500,000 ohm.cm and which has spaced-apart substantially flat surfaces;
(b) contact layers which are directly bonded to the flat surfaces of the resistive element, and are composed of a second conductive material having a resistivity at 23°
C. which is less than the resistivity at 23°
C. of the first material; and(c) at least two further members which are composed of a third conductive material having a resistivity at 23°
C. which is less than the resisitivity at 23°
C. of the second material, which are in the form of continuous elongate metallic connection members which have substantially flat surfaces which are pressed direct physical contact with the contact layers, and are maintained in such contact substantially only by means of pressure over a connection area which is at least 0.5 square inch in area or which has at least one dimension greater than 1 inch,the components of the heating element being positioned such that the heating element can be connected to a source of electrical power, and when it is so connected, current can flow through an electrical path from the further members to the resistive element, through the contact layers; (2) an insulating jacket which surrounds the heating element; (3) a laminar metallic member which (i) provides a ground plane for the device, (ii) is separated from the device by the insulating jacket, and (iii) is adjacent to the insulating jacket but is not secured directly thereto, thus permitting relative movement of the metallic member and the insulating jacket; and (4) an auxiliary laminar insulating member which is secured to the insulating jacket so as to form a pocket having the metallic member moveably contained therein.
- C. of 1 to 500,000 ohm.cm and which has spaced-apart substantially flat surfaces;
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25. An electrical device which comprises
(1) a heating element comprising (a) a laminar resistive element which is composed of a first conductive material which has a resistivity at 23° - C. of 1 to 500,000 ohm.cm and which has spaced-apart substantially flat surfaces;
(b) contact layers which are directly bonded to the flat surfaces of the resistive element, and are composed of a second conductive material having a resistivity at 23°
C. which is less than the resistivity at 23°
C. of the first material; and(c) further members which are composed of a third conductive material having a resistivity at 23°
C. greater than 1×
10-5 ohm.cm but less than the resistivity at 23°
C. of the second material, which provide a plurality of electrodes, and which are in direct physical contact with and bonded to the contact layer, the components of the heating element being positioned such that the heating element can be connected to a source of electrical power and when it is so connected, current can flow through an electrical path from the electrodes of the further members to the resistive element, through the contact layer;(2) an insulating jacket which surrounds the heating element; (3) a laminar metallic member which (i) provides a ground plane for the device, (ii) is separated from the device by the insulating jacket, and (iii) is adjacent to the insulating jacket but is not secured directly thereto, thus permitting relative movement of the metallic member and the insulating jacket; and (4) an auxiliary laminar insulating member which is secured to the insulating jacket so as to form a pocket having the metallic member moveably contained therein.
- C. of 1 to 500,000 ohm.cm and which has spaced-apart substantially flat surfaces;
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26. An electrical device which comprises
(1) a laminar resistive element composed of a first conductive material having a resistivity at 23° - C. of 1 to 500,000 ohm.cm and comprising spaced apart substantially flat surfaces, which flat surfaces are in the same plane;
(2) interdigitated contact layers, composed of a second conductive material having a resistivity at 23°
C. which is less than the resistivity of the first material, the contact layers being directly bonded to respective ones of the substantially flat surfaces; and(3) interdigitated further members composed of a third conductive material having a resistivity at 23°
C. greater than 1×
10-5 ohm.cm but less than the resistivity at 23°
C. of the second material, the further members being bonded to respective ones of the contact layers to provide a plurality of interdigitated electrodes, which are positioned and shaped such that when they are connected to a source of electrical power, cause current to flow between them, through and in the plane of the resistive element.
- C. of 1 to 500,000 ohm.cm and comprising spaced apart substantially flat surfaces, which flat surfaces are in the same plane;
Specification