Contactless passive sensing for absorbent articles

1. An absorbent article facilitating sensing the presence of a body exudate in the absorbent article, the article comprising:

an absorbent member;

a sensor coil disposed on or in the article; and

an electrical double-layer capacitor disposed on or in the article and in electrical communication with the sensor coil, wherein the capacitor is in fluid communication with the absorbent member.

2. The article of claim 1 , wherein the electrical double-layer capacitor includes a pair of plates each having a proximal end adjacent the sensor coil and a distal end spaced apart from the sensor coil.

3. The article of claim 2 , wherein the plates taper in width from the proximal end to the distal end.

4. The article of claim 3 , wherein at least one plate includes conductive paper.

5. The article of claim 4 , wherein the conductive paper includes conductive fibers with a total surface area of at least 5 square meters per gram of conductive paper.

6. The article of claim 4 , wherein the conductive paper includes conductive fibers with a total surface area of at least 100 square meters per gram of conductive paper.

7. The article of claim 1 , wherein the electrical double-layer capacitor is configured to receive an excitation voltage from the sensor coil, and wherein the excitation voltage is less than 100 mv.

8. The article of claim 1 , wherein the electrical double-layer capacitor is configured to receive an excitation voltage from the sensor coil, and wherein the excitation voltage is less than 50 mv.

9. The article of claim 1 , wherein the electrical double-layer capacitor is configured to receive an excitation voltage from the sensor coil, and wherein the excitation voltage is less than 10 mv.

10. The article of claim 1 , wherein the article includes an outer surface, and wherein the sensor coil is disposed on the outer surface.

11. The article of claim 10 , wherein the sensor coil is printed on the outer surface.

12. The article of claim 1 , wherein the article includes a cover sheet having an inner surface and an outer surface, and wherein the sensor coil is disposed on the inner surface.

13. The article of claim 12 , wherein the sensor coil is printed on the inner surface.

14. An absorbent article system for sensing and indicating the presence of a body exudate in an absorbent article, the system comprising:

an absorbent article including

an absorbent member,

a sensor coil disposed on or in the article, and

an electrical double-layer capacitor disposed on or in the article and in electrical communication with the sensor coil, wherein the capacitor is in fluid communication with the absorbent member; and

a detector circuit including

an exciter coil configured for electromagnetic communication with the sensor coil, and

sensor electronics configured to indicate the presence of a body exudate based on changes in the electromagnetic communication between the exciter coil and the sensor coil.

15. The system of claim 14 , wherein the detector circuit is disposed within a housing.

16. The system of claim 14 , wherein the electrical double-layer capacitor includes a pair of plates each having a proximal end adjacent the sensor coil and a distal end spaced apart from the sensor coil, wherein the plates taper in width from the proximal end to the distal end, and wherein at least one plate includes conductive paper.

17. The system of claim 14 , wherein the article includes an outer surface, and wherein the sensor coil is disposed on the outer surface.

18. The system of claim 14 , wherein the article includes a cover sheet having an inner surface and an outer surface, and wherein the sensor coil is disposed on the inner surface.

19. The system of claim 14 , wherein the detector circuit is adapted to provide a wireless notification.

20. The system of claim 14 , wherein the detector circuit is adapted to be held adjacent the absorbent article.