Absorbent article comprising a liquid discharge sensor

Patent metadata

Field	Value
Publication number	US-9194833-B2
Application number	US-201113996944-A
Country	US
Kind code	B2
Filing date	Dec 20, 2011
Priority date	Dec 23, 2010
Publication date	Nov 24, 2015
Grant date	Nov 24, 2015

Abstract

An absorbent article for absorbing liquid discharge of a wearer includes conductive loops each in an open loop shape having terminal ends for electrically communicating with opposing poles of an electric potential generator such that current flows around the full conductive loop between the terminal ends when a space defined within the open loop shape is dry and such that liquid discharge in the space defined within the open loop shape is able to cause a short circuit in the conductive loop so that the current flows around a reduced impedance path. The impedance change is measurable to determine a location relative to the terminal ends where the liquid discharge has caused the short circuit. The conductive loops are oriented such that the direction in which the current travels up an outward leg of the respective conductive loop is in substantially the opposite direction for a first conductive loop as for a second conductive loop.

First claim

The invention claimed is:

1. An absorbent article for absorbing liquid discharge of a wearer when worn in the crotch region, the liquid discharge being urination, menstruation or liquid faecal matter, the absorbent article comprising at least one conductive loop in an open loop shape having terminal ends for electrically communicating with opposing poles of an electric potential generator such that current flows around the full conductive loop between the terminal ends when a space defined within the open loop shape is dry and such that liquid discharge in the space defined within the open loop shape is able to cause a short circuit in the conductive loop so that the current flows around a reduced impedance path as compared to the impedance of the full conductive loop, wherein the impedance change is measurable to determine a location relative to the terminal ends where the liquid discharge has caused the short circuit, wherein the at least one conductive loop is a first conductive loop, the article comprises a second such conductive loop, and wherein the first and second conductive loops are oriented such that the direction in which the current travels up an outward leg of the respective conductive loop is in substantially the opposite direction for the first conductive loop as for the second conductive loop.

2. The absorbent article of claim 1 , wherein the conductive loops is located so as to short circuit under liquid discharge within an absorbent core of the absorbent article.

3. The absorbent article of claim 2 , wherein the terminal ends respectively provide a start and finish point of the conductive loop with respect to the conductive loop being in electrical contact with the absorbent core.

4. The absorbent article of claim 1 , wherein resistance of the conductive loops per centimeter of the conductive loop is at least of the order of 1 Ohms/cm.

5. The absorbent article of claim 1 , wherein the conductive loops comprise or consist of an outward leg, a return leg and a connecting portion therebetween.

6. The absorbent article of claim 5 , wherein the outward leg and the return leg are evenly spaced apart from one another.

7. The absorbent article of claim 5 , wherein the legs are linear and parallel to one another.

8. The absorbent article of claim 1 , wherein the conductive loops are elongate and is positioned in the absorbent article so as to be generally aligned with a longitudinal axis of the absorbent article.

9. The absorbent article of claim 1 , wherein each conductive loop extends over at least 30% of a full longitudinal and/or lateral extent of an absorbent core of the absorbent article.

10. The absorbent article of claim 1 , wherein the conductive loops are embedded in the absorbent core in electrical communication therewith, are placed underneath the absorbent core yet in physical and electrical contact therewith or otherwise placed in electrical contact with the absorbent core.

11. The absorbent article of claim 1 , wherein the first and second conductive loops are the same shape and size as one another when viewed in plan relative to a laid out flat absorbent article.

12. The absorbent article of claim 1 , wherein the first and second conductive loops are arranged so as to respectively short circuit under a liquid discharge absorbed by the absorbent core.

13. The absorbent article of claim 1 , wherein the first and second conductive loops are arranged closely adjacent to one another so that a liquid discharge of about 25 ml centered in a gap between the first and second conductive loops will cause a short circuit in both conductive loops.

14. The absorbent article of claim 1 , further comprising an electrical property measurement unit configured to:
apply a potential between the terminal ends;
measure impedance of the first conductive loop and the second conductive loop; and
determine an extent of liquid discharge in the article based on which of the first plurality of resistors and the second plurality of resistors have been short circuited.

15. The absorbent article of claim 1 , wherein the first plurality of resistors is disposed linearly on an outward leg of the first conductive loop and spaced evenly therealong.

16. A system comprising an absorbent article for absorbing liquid discharge of a wearer when worn in the crotch region of the wearer, wherein the absorbent article comprises at least one conductive loop in an open loop shape having terminal ends, the system comprising an electrical property measurement unit that is configured to apply an electric potential between the terminal ends such that electric current flows around the full conductive loop unless there is a short circuit caused by a liquid discharge in the space defined inside the conductive open loop, the short circuit being so that electric current flows around a reduced impedance path as compared to the impedance of the full loop, and an electrical liquid discharge location unit that is configured to determine a location of the short circuit relative to the terminal ends based on an electrical property measured by the electrical property measurement unit when applying the potential between the terminals of the conductive loop, and predetermined data concerning the electrical property of the conductive path, wherein the at least one conductive loop is a first conductive open loop and the absorbent article comprises a second conductive open loop having terminal ends and the electrical property measurement circuit is configured to also apply a potential between the terminal ends in order to determine the impedance to current flow around the second conductive loop, wherein the liquid discharge location determination unit is configured to determine the location of the liquid discharge relative to the terminal ends of the second conductive loop based on the measured electrical property in the second conductive loop and predetermined data concerning the electrical property of the second conductive loop, wherein the first and second conductive loops are reverse arranged relative to one another so that the position of the short circuits in the first and second conductive loops is caused by opposed ends of a liquid discharge.

17. The system of claim 16 , wherein impedance measurements are taken repeatedly and continuously, and the system comprises a recording unit that is configured to record data produced by the electrical property measurement unit and/or the liquid discharge location unit so that the spread of the liquid discharge over time can be measured and recorded.

18. The system of claim 16 , wherein the electrical property is impedance.

19. An absorbent article for absorbing liquid discharge of a wearer when worn in the crotch region, the liquid discharge being urination, menstruation or liquid faecal matter, the absorbent article comprising at least one conductive loop in an open loop shape having a first plurality of resistors and terminal ends for electrically communicating with opposing poles of an electric potential generator such that current flows around the full conductive loop between the terminal ends when a space defined within the open loop shape is dry and such that liquid discharge in the space defined within the open loop shape is able to cause a short circuit in the conductive loop so that the current flows around a reduced impedance path as compared to the impedance of the full conductive loop, wherein the impedance change is measurable to determine a location relative to the terminal ends where the liquid discharge has caused the short circuit, where

Assignees

• Bosaeus Mattias
• Elfström Allan
• Mellbin Fredrik
• Sca Hygiene Prod Ab

Inventors

• Bosaeus Mattias
• Elfström Allan
• Mellbin Fredrik

Classifications

• G01N27/048 Primary

  for determining moisture content of the material · CPC title

• A61F13/42

  with wetness indicator or alarm · CPC title

• A61B5/6808

  Diapers · CPC title

• G01N27/07

  Construction of measuring vessels; Electrodes therefor · CPC title