Device for electric insulation of a conducting plane

A method for using a distinct electrically conducting area relative to a first electrically conducting outer layer of a device for electric insulation of an electrically conducting plane having a first electric potential relative to a second electric potential, comprising the step of:

• reducing the value of the electrostatic field in a point of a peripheral edge of the first outer layer relative to the value of the electrostatic field in this point in the absence of the conducting area, the device comprising an insulating substrate including two planar surfaces parallel to each other, the first substantially planar outer layer positioned on a first planar surface of the insulating substrate, the first outer layer forming the electrically conducting plane able to be connected to the first potential and having a peripheral edge, and the second surface being able to be connected to the second electric potential, the conducting area being positioned in the insulating substrate and the conducting area having an electric potential of value between the values of the first and second electric potentials
• wherein the device comprises:
• an insulating substrate including first and second planar surfaces parallel to each other, a first electrically conducting, substantially planar, outer layer positioned on the first planar surface of the insulating substrate, the first outer layer forming the electrically conducting plane able to be connected to the first potential and having a peripheral edge, the second surface being able to be connected to the second electric potential, and
• an electrostatic field reducer for reducing the value of the electrostatic field in a point of the peripheral edge of the outer layer, the reducer including at least one electrically conducting area distinct from the first outer layer, positioned in the insulating substrate, the reducer being able to reduce the value of the electrostatic field in this point relative to the value of the electrostatic field in this point in the absence of the conducting area, the conducting area having an electric potential between the values of the first and second electric potential,
• the reducer including N conducting areas, N being an integer, each of the conducting areas having a distinct electric potential between the values of the first and second electric potentials,
• each of the conducting areas including an electrically conducting intermediate layer positioned in the insulating substrate parallel to the first outer layer, each of the electrically conducting intermediate layers including a peripheral edge,
• each of the conducting areas further including a guard ring, each of the guard rings being positioned in a plane of and surrounding a different one of the first outer conducting layer and the intermediate conducting layers except for a central intermediate layer of the intermediate conducting layers, the spacing between each of the guard rings and the peripheral edge of the first or intermediate conducting layer the guard ring surrounds being equal to a predetermined distance, each of the guard rings being electrically connected to one of the intermediate conducting layers having a different potential than the first or intermediate conducting layer the guard ring surrounds.