Apparatus monitoring the deposition of a liquid-to-pasty medium on a substrate

A device for monitoring deposition of a medium on a substrate, said device comprising:

• a device input and a device output, said device input being connectable to an AC voltage source;
• a first electrode connected to said device input;
• a second electrode physically spaced from said first electrode by a distance sufficient to allow the substrate carrying the medium to pass between said electrodes, said first and second electrodes being electrically isolated from each other thereby forming a sensoring capacitor;
• and
• a measuring circuit electrically connected to said second electrode and said device output, said circuit being adapted to measure the imaginary component of a dielectric constant of the substrate and the medium situated between said electrodes, and generate, at said device output, a signal corresponding to the measured dielectric constant.

An apparatus for monitoring deposition of a medium on a substrate, said apparatus comprising:

• at least one sensor comprising a capacitor having two electrodes which are sufficiently spaced from each other to allow the substrate carrying the medium to be positioned between said electrodes;
• measuring means for measuring the imaginary component of the dielectric constant of the substrate together with the medium situated between said electrodes, said measuring means being electrically coupled to at least one of said electrodes;
• and
• outputting means for generating a signal characteristic of the substrate together with the medium based on the measured imaginary component, said outputting means being electrically coupled to said measuring means.

A method of monitoring deposition of a liquid-to-pasty medium on a substrate, said method comprising the steps of:

• positioning first and second electrodes on opposite sides of the substrate so that the electrodes are physically spaced from each other by a distance sufficient to allow the substrate carrying the medium to pass between the electrodes, the first and second electrodes being electrically isolated from each other to form a sensoring capacitor;
• applying an AC voltage to the first electrode, causing an amount of energy to be transferred across the distance, through the substrate and the medium, to the second electrode;
• measuring a loss of the energy in the substrate and the medium;
• and
• based on the measured energy loss, determining the imaginary component of an dielectric constant of the substrate and the medium situated between the electrodes.

In combination, a substrate and a device for monitoring deposition of a liquid-to-pasty medium on the substrate, said device comprising:

• a device input and a device output, said device input being connectable to an AC voltage source;
• a first electrode connected to said device input;
• a second electrode physically spaced from said first electrode by a distance sufficient to allow the substrate to pass between said electrodes, said first and second electrodes being electrically isolated from each other thereby forming a sensoring capacitor, the substrate continuously moving in spaced relationship with respect to said electrodes;
• and
• a measuring circuit electrically connected to said second electrode and said device output, said circuit measuring the imaginary component of an dielectric constant of a portion of the substrate which is currently situated between said electrodes, said circuit further generating, at said device output, a signal corresponding to the measured dielectric constant.