Absorbent article comprising a wetness detector

An absorbent article comprising:

• an electrically insulating back sheet;
• an absorbent core on a body side of the back sheet;
• at least one liquid discharge sensor on a back side of the back sheet;
• and
• at least one hole through the back sheet communicating the at least one liquid discharge sensor with the absorbent core, so that the liquid discharge sensor exhibits a changed electrical property when a part of the absorbent core associated with the liquid discharge sensor through the at least one hole changes from a dry state to a wet state,
• wherein the at least one liquid discharge sensor comprises conductive material that is partly communicated with the absorbent core by the at least one hole,
• wherein there is a plurality of conductive lines forming the at least one liquid discharge sensor, each of which lines are partly revealed by the at least one hole,
• wherein the at least one liquid discharge sensor is disposed on a carrier sheet or substrate,
• wherein the at least one liquid discharge sensor comprises at least one conductive path formed in the shape of an open loop that is able to carry a current around the loop,
• wherein the at least one hole reveals to the absorbent core part of an outward leg and part of a return leg, and
• wherein if the absorbent core is wet between the exposed part of the legs, then a short circuit will form between the exposed part of the legs as opposed to current flow around the full open loop shaped conductive path.

An absorbent article comprising:

• an electrically insulating back sheet;
• an absorbent core on a body side of the back sheet;
• at least one liquid discharge sensor on a back side of the back sheet;
• and
• at least one hole through the back sheet communicating the at least one liquid discharge sensor with the absorbent core, so that the liquid discharge sensor exhibits a changed electrical property when a part of the absorbent core associated with the liquid discharge sensor through the at least one hole changes from a dry state to a wet state,
• wherein the at least one liquid discharge sensor comprises conductive material that is partly communicated with the absorbent core by the at least one hole,
• wherein there is a plurality of conductive lines forming the at least one liquid discharge sensor, each of which lines are partly revealed by the at least one hole,
• wherein the at least one liquid discharge sensor is disposed on a carrier sheet or substrate,
• wherein a plurality of conductive lines are disposed on a first electrically insulating layer forming the carrier sheet or substrate that are partially covered by the back sheet,
• wherein portions of the conductive lines exposed by the at least one hole in the back sheet are in electrical communication with the absorbent core, thereby providing electrodes of the at least one liquid discharge sensor, and
• wherein portions of the conductive lines covered by the back sheet include leads extending between each electrode and a control unit attachment area, the back sheet ensuring the leads are electrically insulated from the absorbent core, wherein the electrodes are arranged so that a plurality of longitudinally spaced liquid detection zones are provided, each detection zone defined between a pair of electrodes that are electrically isolated from one another when the absorbent core is dry and which are arranged so that when the control unit connects an electric potential to corresponding leads and when the absorbent core is wet, a conductive bridge is formed between the pair of electrodes by the wet absorbent core, wherein a longitudinal axis extends in a front to rear direction of the absorbent article when worn.

An absorbent article comprising:

• an electrically insulating back sheet;
• an absorbent core on a body side of the back sheet;
• at least one liquid discharge sensor on a back side of the back sheet, and
• a plurality of holes through the back sheet communicating the at least one liquid discharge sensor with the absorbent core, so that the liquid discharge sensor exhibits a changed electrical property when a part of the absorbent core associated with the liquid discharge sensor through at least one of the plurality of holes changes from a dry state to a wet state,
• wherein the at least one liquid discharge sensor comprises conductive material that is partly communicated with the absorbent core by at least one of the plurality of holes,
• wherein the at least one liquid discharge sensor comprises a plurality of conductive lines, each of which lines are partly revealed by at least one of the plurality of holes,
• wherein the at least one liquid discharge sensor is disposed on a carrier sheet or substrate, and
• wherein each of the holes of the plurality of holes is longitudinally spaced along a longitudinal axis from each of the other of the plurality of holes, the longitudinal axis extending in a front to rear direction of the absorbent article.