Data logger unit, sensor unit, absorbent article management system, and identification method

Abstract

To provide more flexible means of measuring and monitoring the absorbent status of absorbent articles.SOLUTION: The present invention relates to data logger units and sensor units, and specifically data logger units and sensor units which are suitable for sensing the hygienic state of an absorbent article. The present disclosure also relates to a method of identifying a sensor unit for an absorbent article practiced by a data logger unit adapted to cooperate with the sensor unit, as well as an absorbent article management system. The data logger unit and the sensor have identification terminals. A characteristic of the sensor unit is encoded in the potentials at each of the identification terminals. The data logger unit can decode the potentials at each of the identification terminals to determine the characteristic of a connected sensor unit.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a data logger unit, a sensor unit, and in particular to a data logger unit, a sensor unit suitable for detecting the hygiene state of an absorbent article. The present disclosure also relates to a method for identifying a sensor unit for an absorbent article, which is implemented by a data logger unit adapted to cooperate with the sensor unit, and an absorbent article management system. [Background technology]

[0002] Absorbent articles such as diapers, absorbent undergarments, sanitary products, and incontinence shields must be changed periodically during use to prevent the absorbency of the article from being compromised.

[0003] In many environments, such as home, institutional, and medical environments, it is necessary to monitor the condition of the absorbent article provided to the user to ensure that the article contains sufficient absorbent capacity to perform its function.

[0004] Traditionally, such monitoring may be performed as self-monitoring by the user, who notifies care staff when the absorbent capacity of the absorbent article has decreased, or by regular testing by the user or care staff. However, such a process is labor-intensive. Furthermore, the information collected regarding the user's personal needs regarding how often the absorbent article needs to be changed or the required capacity of the absorbent article is time-consuming to compile, frequently collected, and incomplete.

[0005] It has therefore been proposed to provide an absorbent article that includes a sensor coupled to data logging electronics that can determine the absorbency state of the absorbent article and, for example, can notify a caregiver when the absorbency state of the absorbent article has reached a predetermined state.

[0006] A configuration has been proposed that uses sensing wires embedded in the absorbent core of an absorbent article, whereby data logging electronics measures the resistance between each wire to determine whether liquid is present in the absorbent core and therefore the condition of the absorbent article.

[0007] In some configurations, the data logger can notify the user or a nearby caregiver by an appropriate visual or audible signal that liquid is present in the core and that the absorbent article therefore needs to be changed.

[0008] It has also been proposed to use such logging electronics as part of an absorbent article management system. In such a system, the data logging electronics may communicate the absorbency status of the absorbent article to a remote terminal. The remote terminal can be used to monitor the absorbency status of the absorbent article. Such a management system is particularly useful in baby care or hospital environments where users have difficulty communicating their needs to staff.

[0009] In some systems, a remote terminal may aggregate information recorded from multiple data loggers associated with each user, such that the absorption status of multiple items associated with multiple respective users can be conveniently monitored with reduced manpower requirements.

[0010] However, providing such articles with sensors and data logging electronics, and thus providing such systems, can require significant capital investment, as absorbent articles with such sensors and data logging electronics have significantly higher unit costs than manually monitored absorbent articles, and this higher cost is significant because absorbent articles typically need to be replaced frequently, on the order of several times per user day.

[0011] To address this, it has been proposed to provide data logging electronics and corresponding sensors in a separate logging package that may be removably mounted to an absorbent article for monitoring a suitably designed absorbent article, and when the article is replaced, the logging package can be removed and attached to the replacement article.

[0012] However, such sensors are difficult to incorporate into the absorbent core of an absorbent article, and therefore, systems that use replaceable logging packages may have reduced sensing capabilities. Furthermore, because absorbent articles often come in a range of shapes and sizes, a logging package that is suitable for attachment to one type or size of absorbent article may perform poorly when used in combination with another type or size of absorbent article.

[0013] Therefore, there is a need for a more versatile means of measuring and monitoring the absorbency of absorbent articles that overcomes at least some of the drawbacks associated with conventional designs. Summary of the Invention [Means for solving the problem]

[0014] According to a first aspect of the present invention, there is provided a method for identifying a sensor unit for an absorbent article by a data logger unit. The sensor unit comprises a sensor terminal portion. The sensor unit comprises at least one sensing element. The at least one sensing element is electrically connected to at least one measurement terminal of the sensor terminal portion. The data logger unit comprises a logger terminal portion. The data logger unit comprises a measurement module electrically connected to the at least one sensing terminal of the logger terminal portion. The sensor terminal portion engages with the logger terminal portion. The engagement may include electrically connecting a terminal of the sensor terminal portion to a corresponding terminal of the logger sensor portion. The data logger unit is adapted to perform electrical measurements of the at least one sensing element. The measurements are performed via the at least one measurement terminal of the sensor terminal portion. The measurements are performed via the at least one measurement terminal of the logger terminal portion. The data logger unit has a plurality of identification terminals at the logger terminal portion. The plurality of identification terminals are electrically connected to the measurement module. The sensor terminal portion has a plurality of identification terminals at the sensor terminal portion. The measurement module performs electrical measurements of the identification terminals of the logger terminal section. The measurements are performed to identify characteristics of the sensor unit. The characteristics of the sensor unit are coded in the potentials of the identification terminals of the sensor terminal section.

[0015] The sensor-side terminal section may have a reference terminal. The logger-side terminal section may have a reference terminal. The measurement module may supply a reference potential to the reference terminal of the logger-side terminal section. At least one of the identification terminals of the sensor-side terminal section may be electrically connected to the reference terminal of the sensor-side terminal section via a conductor of the sensor unit. A characteristic of the sensor unit may be coded by the potential at each identification terminal of the sensor-side terminal section relative to the reference potential.

[0016] A resistor in the data logger unit may be electrically connected between each identification terminal of the sensor-side terminal section and a conductor in the data logger unit maintained at a potential supplied by the measurement module that is different from the reference potential.

[0017] One or more of the identification terminals of the sensor-side terminal section may be electrically connected to the reference terminal of the sensor-side terminal section by a conductor of the sensor unit, and the remaining identification terminals of the sensor-side terminal section may not be electrically connected to the sensor reference terminal.

[0018] The reference potential may be the ground potential of the measurement module.

[0019] The reference terminal of the sensor-side terminal section may be a ground reference terminal. The reference terminal of the sensor-side terminal section may be a ground reference terminal. The ground reference terminal of the logger-side terminal section may be connected to the ground of the measurement module by a conductor of the data logger unit. One or more of the identification terminals of the sensor-side terminal section may be electrically connected to the sensor ground reference terminal by a conductor of the sensor unit.

[0020] The reference potential may be a potential different from the ground potential of the measurement module.

[0021] The reference terminal of the sensor terminal section may be a supply terminal. The reference terminal of the logger terminal section may be a supply terminal. The supply terminal of the logger terminal section may be electrically connected to the supply potential of the measurement module by a conductor of the data logger unit. One or more of the identification terminals of the sensor terminal section may be electrically connected to each other and to the sensor supply terminal by a conductor of the sensor unit.

[0022] The sensor-side terminal section may have a ground reference terminal. The logger-side terminal section may have a ground terminal. The ground reference terminal of the logger-side terminal section may be connected to the ground potential of the measurement module by a conductor of the data logger unit.

[0023] The characteristics of the sensor unit may be determined by identifying a single terminal among the identified terminals of the logger terminal section as the terminal having the reference potential, and the identified terminal may be correlated with the characteristics.

[0024] The characteristics of the sensor unit may be determined by identifying a set of identified terminals of the logger terminal section as terminals having a reference potential, and the identified set of terminals may be correlated with the characteristics.

[0025] The potential of the identification terminal of the logger terminal section may define a sequence of binary numbers, and the data logger unit may decode from the sequence of binary numbers a value that correlates with the characteristic.

[0026] The sensing element may be provided on a flexible substrate of the sensor unit.

[0027] The flexible substrate may be elongated along the long axis, and the sensing element may comprise a plurality of conductive plates arranged along the long axis of the flexible substrate.

[0028] The flexible substrate may be elongated along the longitudinal axis. The sensing element may include one or more pairs of elongated conductive plates. Each pair of conductive plates may be arranged transverse to the longitudinal axis such that one plate of the pair is on one side of the longitudinal axis and the other plate of the pair is on the other side of the longitudinal axis.

[0029] The sensing element may be disposed on one surface of a flexible substrate, and the conductive region may be disposed such that the other surface of the flexible substrate is on a side where one or more pairs of conductive plates are disposed to underlie the sensing element.

[0030] The conductive plate may be connected to the ground potential of the measurement module via the ground terminal of the sensor-side terminal portion.

[0031] A data logger unit may be removably attached to the sensor unit before the measurement module performs electrical measurements.

[0032] After the measurement module has performed the electrical measurements, the data logger unit may be removed from the sensor unit and attached to another sensor unit.

[0033] According to a second aspect of the present invention, there is provided a data logger unit for receiving data from a sensor unit provided in an absorbent article. The data logger unit comprises a logger terminal portion and a measurement module electrically connected to at least one measurement terminal of the logger terminal portion. The logger terminal portion is adapted to engage with a sensor terminal portion of the sensor unit. This connection is for connecting the sensor unit and the data logger unit. The measurement module is arranged to perform electrical measurements via the at least one measurement terminal of the logger terminal portion. The data logger unit has a plurality of identification terminals at the logger terminal portion. The plurality of identification terminals are electrically connected to the measurement module. The measurement module is configured to perform measurements on the plurality of identification terminals. The measurements are performed to identify a characteristic of the sensor unit. The characteristic of the sensor unit is coded in the potential of the identification terminal.

[0034] The logger terminal section may have a reference terminal. The measurement module may be configured to supply a reference potential to the reference terminal of the logger terminal section. The characteristics of the sensor unit may be coded by the potential at each identification terminal of the logger terminal section relative to the reference potential.

[0035] A resistor in the data logger unit may be electrically connected between each identification terminal of the logger terminal section and a conductor in the data logger unit that is maintained at a potential supplied by the measurement module that is different from the reference potential.

[0036] The reference potential may be the ground potential of the measurement module.

[0037] The reference terminal of the logger terminal section may be a ground reference terminal, which may be connected to the ground of the measurement module by a conductor of the data logger unit.

[0038] The reference potential may be a potential different from the ground potential of the measurement module.

[0039] The reference terminal of the logger-side terminal section may be a supply terminal, which may be electrically connected to the supply potential of the measurement module by a conductor of the data logger unit.

[0040] The logger-side terminal section may have a ground terminal, which may be connected to the ground potential of the measurement module by a conductor of the data logger unit.

[0041] The characteristics of the sensor unit may be determined by identifying a single terminal among the identified terminals of the logger terminal section as the terminal having the reference potential. The identified terminal may be correlated with the characteristics.

[0042] The measurement module may be configured to determine a characteristic of the sensor unit by identifying a set of identified terminals of the logger terminal section as terminals having a reference potential, and the identified set of terminals may be correlated with the characteristic.

[0043] The potentials at the identification terminals may define a sequence of binary numbers, and the data logger unit may decode from the sequence of binary numbers a value that correlates to the characteristic.

[0044] The data logger unit may be removably attachable to the sensor unit.

[0045] The data logger unit may be removably attachable to the absorbent article.

[0046] The measurement module may be adapted to repeat taking the electrical measurements after the data logger unit is removed from the sensor unit and attached to another sensor unit.

[0047] According to a third aspect of the present invention, there is provided a sensor unit for an absorbent article, which is connected to a data logger unit to determine the hygiene state of the absorbent article. The sensor unit comprises a sensor terminal portion. The sensor unit comprises at least one sensing element electrically connected to at least one measurement terminal of the sensor terminal portion. The sensor terminal portion is adapted to engage with a logger terminal portion of the data logger unit. The engagement connects the sensor unit and the data logger unit. The sensor terminal portion has a plurality of identification terminals at the sensor terminal portion. The identification terminals of the sensor terminal portion are configured to indicate characteristics of the sensor unit by electrical measurements of the plurality of identification terminals. The characteristics of the sensor unit are coded by the potential of the identification terminals of the sensor terminal portion when connected to the data logger unit.

[0048] The sensor-side terminal section may have a reference terminal. At least one of the identification terminals of the sensor-side terminal section may be electrically connected to the reference terminal of the sensor-side terminal section via a conductor of the sensor. The characteristics of the sensor unit may be coded by the potential at each identification terminal of the sensor-side terminal section relative to a reference potential.

[0049] One or more of the identification terminals of the sensor-side terminal section may be electrically connected to the reference terminal of the sensor-side terminal section by a conductor of the sensor unit, and the remaining identification terminals of the sensor-side terminal section may not be electrically connected to the sensor reference terminal.

[0050] The reference terminal of the sensor-side terminal section may be a ground reference terminal, and one or more of the identification terminals of the sensor-side terminal section may be electrically connected to each other and to the ground reference terminal of the sensor-side terminal section by a conductor of the sensor unit.

[0051] The reference terminal of the sensor-side terminal unit may be a supply terminal. One or more of the identification terminals of the sensor-side terminal unit may be electrically connected to each other and to a sensor supply terminal of the sensor-side terminal unit by a sensor conductor.

[0052] The sensor-side terminal portion may include a ground reference terminal.

[0053] The characteristics of the sensor unit may be determined by identifying a single terminal among the sensor identification terminals of the sensor terminal portion as the terminal having the reference potential. The identified terminal may be correlated with the characteristics.

[0054] The characteristic of the sensor unit may be determined by identifying a plurality of terminals of the sensor terminal section as terminals having a reference potential, among identified terminals of the sensor terminal section, and the set of identified terminals may be correlated with the characteristic.

[0055] The potential of the identification terminal of the sensor terminal portion may define a sequence of binary numbers, which may be decoded into a value that correlates with the characteristic.

[0056] The sensing element may be provided on a flexible substrate.

[0057] The flexible substrate may be elongated along the long axis, and the sensing element may comprise a plurality of conductive plates arranged along the long axis of the flexible substrate.

[0058] The flexible substrate may be elongated along the longitudinal axis. The sensing element may include one or more pairs of elongated conductive plates, each pair arranged transverse to the longitudinal axis such that one plate of the pair is on one side of the longitudinal axis and the other plate of the pair is on the other side of the longitudinal axis.

[0059] The sensing element may be disposed on one surface of a flexible substrate, and the conductive region may be disposed such that the other surface of the flexible substrate is on a side where one or more pairs of conductive plates are disposed to underlie the sensing element.

[0060] The conductive plate may be connected to the ground terminal of the sensor-side terminal portion.

[0061] The sensor unit may be removably attachable to the data logger unit.

[0062] The sensor unit may be removably attachable to the absorbent article.

[0063] The sensor unit may be configured to contactlessly detect the presence of bodily fluid within the absorbent article in proximity to the sensor unit.

[0064] According to a fourth aspect of the present invention, there is provided a plurality of replaceable sensor units according to the third aspect. Each of the plurality of replaceable sensor units has a common configuration of sensor-side terminals. The sensor-side terminals are adapted to engage with logger-side terminals of a common data logger unit. This engagement allows the sensor units to be exchanged in association with the data logger unit. The characteristics may differ between the replaceable sensor units. The characteristics may be uniquely specified by the potential of an identification terminal of the sensor-side terminal of each sensor unit when connected to the data logger unit.

[0065] The characteristic may be the length of the sensor unit in the extension direction.

[0066] The property may be an electrical property associated with at least one sensing element.

[0067] The at least one sensing element may comprise two elongated sensing elements arranged parallel to one another, and the characteristic may be a capacitance between the sensing elements.

[0068] The characteristic may be a dimension associated with at least one sensing element.

[0069] The multiple interchangeable sensor units may be removably attached to a common data logger unit.

[0070] According to a fourth aspect of the present invention, there is provided an absorbent article management system. The absorbent article management system includes a data logger unit according to the second aspect. The absorbent article management system includes a sensor unit according to the third aspect. The sensor unit is provided on an absorbent article such that at least one sensing element is positioned to determine the hygiene state of the absorbent article. The data logger unit is configured to perform the method of the first aspect when the data logger unit is connected to the sensor unit. The data logger unit periodically performs electrical measurements of the at least one sensing element via at least one measurement terminal of the sensor-side terminal portion and at least one measurement terminal of the logger-side terminal portion. The data logger unit may identify characteristics of the sensor unit by relating information about the results of the electrical measurements to information about the potential of the identification terminal of the sensor-side terminal portion.

[0071] The data logger unit may comprise a data storage unit, which may be adapted to store information relating to the results of the electrical measurements in association with information identifying a characteristic of the sensor unit.

[0072] The absorbent article management system may further comprise a remote terminal. The data logger unit may comprise a communication unit configured to transmit data to the remote terminal. The communication unit may be configured to transmit information regarding the results of the electrical measurements to the communication unit in association with information identifying the characteristics of the sensor unit.

[0073] The remote terminal may comprise a database adapted to store information relating to the results of the electrical measurements in association with information identifying characteristics of the sensor unit.

[0074] The data logger unit may be adapted to decode the potential of the identification terminal of the logger terminal portion to provide information relating to the characteristics.

[0075] The remote terminal may be configured to decode the potential of the identification terminal of the logger terminal section to provide information about the characteristics.

[0076] For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which: [Brief explanation of the drawings]

[0077] [Figure 1] 1 is a diagram showing an absorbent article provided with a sensor unit according to one embodiment of the present invention. [Figure 2] FIG. 1 is a diagram showing a sensor unit according to an embodiment of the present invention. [Figure 3] FIG. 1 is a diagram showing a combination of a sensor unit and a data logging unit according to an embodiment of the present invention. [Figure 4] FIG. 10 is a diagram showing a data logging unit according to an embodiment of the present invention with the terminal area exposed. [Figure 5] FIG. 10 shows a data logging unit according to an embodiment of the present invention, in which the terminal area is covered by a clamp bar. [Figure 6] FIG. 10 shows a combined sensor unit and data logging unit according to one embodiment of the present invention with the terminal areas aligned. [Figure 7] FIG. 10 illustrates a combined sensor unit and data logging unit according to one embodiment of the present invention, with the terminal area covered by a clamp bar. [Figure 8] 1 is a schematic electrical circuit diagram of a data logging unit according to an embodiment of the present invention; [Figure 9] 1 is a schematic electrical circuit diagram of a sensor unit according to an embodiment of the present invention. [Figure 10] FIG. 10 is a schematic electrical circuit diagram of a data logging unit according to an alternative embodiment of the present invention. [Figure 11] FIG. 10 is a schematic electrical circuit diagram of a data logging unit according to another alternative embodiment of the present invention. [Figure 12] FIG. 10 is a schematic electrical circuit diagram of a data logging unit according to another alternative embodiment of the present invention. [Figure 13] FIG. 10 is a schematic electrical circuit diagram of a data logging unit according to another alternative embodiment of the present invention. [Figure 14] FIG. 10 is a schematic electrical circuit diagram of a data logging unit according to another alternative embodiment of the present invention. [Figure 15] FIG. 10 is a schematic electrical circuit diagram of a data logging unit according to another alternative embodiment of the present invention. [Figure 16] 1 is a block diagram of a data logging unit and a remote terminal forming an absorbent article management system and according to one embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0078] 1 shows an exemplary configuration of an absorbent article 900, specifically a diaper. The diaper 900 has a front waist region 920, a back waist region 930, and a crotch region 940 connecting the front waist region 920 to the back waist region 930. The diaper 900 has an outer surface that faces away from the user when worn, and an inner surface that faces toward the user when worn.

[0079] In the configuration of the diaper 900 shown in Figure 1, the front waist portion has tab portions 921 and 922 that are adapted to engage with corresponding tab portions 924 and 925 provided on the rear waist portion 930. For example, the tab portions 921 and 922 may include attachment areas and be arranged to adhere to the attachment areas provided on the tab portions 924 and 925, thereby allowing the diaper 900 to fit securely around the waist of the user.

[0080] The diaper 900 also has an absorbent core configured to absorb liquid and / or solid waste from the user into the diaper when worn. The construction of such a core, and the construction of the remainder of the diaper, may be conventional constructions known in the art. For example, the core may include an absorbent material, such as a superabsorbent polymer, alone or in combination with additional components, such as cellulosic fibers, in an absorbent layer, and may include one or more additional layers having functions such as liquid acquisition, liquid distribution, and leak prevention.

[0081] The diaper 900 may have, on its inner surface, a water-permeable topsheet that softly covers the core 910. The diaper 900 may have, on its outer surface, a water-impermeable backsheet to prevent leakage, with the absorbent core 910 disposed between the water-permeable topsheet and the water-impermeable backsheet. Such diaper constructions are known in the art. It should be noted that the backsheet is generally water-impermeable, but may or may not be moisture vapor permeable, i.e., breathable.

[0082] The diaper 900 includes a sensor unit 100 whose function, in cooperation with appropriate measurement electronics, is to sense the absorbency, e.g., wetness, of the absorbent core 910. The sensor unit 100 is in the form of an elongated, flexible strip and is positioned to overlie the absorbent core 910. When positioned flat, the sensor unit 100 therefore has a longitudinal axis in the direction of elongation and a transverse axis transverse to the axis of elongation, each axis lying in the plane of the strip. The sensor unit 100 need not be rectangular as shown, but could instead be bow-tie shaped with curved edges, oval shaped, or have another elongated shape.

[0083] Absorbent articles such as article 900 that are worn by a user or otherwise placed or secured on or in contact with the user's body are conventionally understood to have an interior and an exterior, the interior being the portion that is placed in contact with the user's body during use, and the exterior being the portion that faces away from the user's body. As shown in Figure 1, the absorbent core 910 is located on the interior of the absorbent article, while the sensor unit 100 is provided on the exterior of the absorbent article, specifically on the side of the backsheet that faces away from the absorbent core 910.

[0084] The sensor unit 100 may be secured to the surface of the absorbent article 900 by an adhesive layer, hook-and-loop fasteners, or other removable or temporary attachment methods known in the art. Advantageously, the sensor unit 100 is designed to be removable from the absorbent article after it has been attached thereto, so that the same sensor unit may be reused on several different absorbent articles.

[0085] The sensor unit 100 includes sensing plates 111, 112, 113, and 114, which act as plates of a plane-parallel plate capacitor. The presence or absence of liquid within the absorbent core may be determined by measuring the impedance between pairs of plates 111, 112, 113, and 114. Without wishing to be bound by theory, the presence of liquid within the absorbent core 910 modifies the dielectric constant of the region below the sensor unit 100, which in turn modifies the dielectric constant of the space above, e.g., plates 111 and 112, thereby affecting the impedance of the capacitor formed by the plates.

[0086] Such a configuration allows for non-contact detection of liquid within the absorbent core, in the sense that there is no direct contact between the bodily fluid and the sensor unit. Thus, the sensor unit 100 can sense the condition of the absorbent core or a region of the absorbent core even when separated from the absorbent core by an impermeable layer, such as an impermeable backsheet. In contrast, for example, resistive sensing configurations tend to require contact between the liquid within the absorbent core and a conductor that serves as the sensing element.

[0087] A more detailed view of an exemplary configuration of sensor unit 100 is shown in Figure 2, viewed from the side of the sensor unit with plates 111, 112, 113, 114 facing the reader. Sensor unit 100 has a flexible substrate 120 on which plates 111, 112, 113, 114 are provided, for example, by surface plating. Flexible substrate 120 may therefore be a flexible printed circuit board (flexible PCB).

[0088] On the side of flexible substrate 120 opposite to the side having plates 111, 112, 113, and 114 is ground plate 130 located below substantially the entire surface of flexible substrate 120, specifically the area carrying plates 111, 112, 113, and 114. The effect on the impedance between plates 111, 112, 113, and 114 may thereby be controlled primarily by the environment above the surface of flexible surface 120 carrying plates 111, 112, 113, and 114, rather than the environment adjacent to the other side of flexible substrate 120.

[0089] Each plate 111, 112, 113, 114 is connected by a respective conductive trace 161, 162, 163, 164 to a respective conductive pad 151, 152, 153, 154 located in the terminal area 140 of the sensor unit.

[0090] The conductive traces 161, 162, 163, 164 and plates 111, 112, 113, 114 may be covered by a layer of dielectric material, such as a thin film on a polymer, whereas the pads 151, 152, 153, 154 are exposed at the surface of the flexible substrate 120, thereby serving as terminals to facilitate connection between the plates 111, 112, 113, 114 and the measurement and data logging electronics described below.

[0091] The configuration of the plates may be varied. For example, more than two pairs of plates may be provided. The plates may be, but need not be, elongated as shown. The plates may be, but need not be, rectangular as shown. The plates may be, but need not be, provided in pairs positioned across the longitudinal axis of the flexible substrate. The plates may be parallel to one another or may be angled relative to one another. Thus, a wide variety of plate arrangements and their respective locations on the flexible substrate are contemplated.

[0092] 1, it is advantageous for the sensor unit 100 to be adapted to the length of the absorbent core 910 of the diaper 900. For example, if the sensor unit 100 is too long, the plates 111, 112, 113, 114 may be located above areas of the diaper 900 that are not expected to absorb liquid, and therefore may have reduced sensitivity or may give erroneous readings due to the influence of other components in the diaper 900. On the other hand, if the sensor unit 100 is significantly shorter than the absorbent core 910 in the longitudinal direction, liquid may accumulate in the absorbent core 910 in positions where the sensor unit 100 cannot detect the presence of liquid.

[0093] Thus, in some embodiments, it may be suitable for sensor unit 100, or at least the portions of sensor unit 100 that hold plates 111, 112, 113, 114, to be coextensive with the absorbent core and have a length and / or width comparable to that of the absorbent core, e.g., between 20% and 100%, possibly between 30% and 80%, or even possibly between 40% and 60% of the respective dimensions of the core. For example, the rectangles joining absorbent core 910 and plates 111, 112, 113, 114 may each have comparable dimensions when flattened.

[0094] 1, the configuration of the core 910 may be significantly more complex than that shown, and the absorbent core 910 may include different regions having different absorbencies and / or different widths. Accordingly, the layout of plates 111, 112, 113, 114 on the sensor unit 100 may be adapted to such a configuration of the absorbent core 910. In such an embodiment, each plate may be positioned to lie within the boundary of the absorbent core, but may also be positioned to be coextensive with a particular location, such as a long-term storage region of the absorbent core.

[0095] Such a configuration ensures that the sensor unit 100 is only most effective when used in conjunction with such an absorbent core, and may be ineffective when used in conjunction with an absorbent core of a different configuration.

[0096] In the most common variations in the absorbent core 910, the size of the diaper 900 is changed to accommodate different user sizes, most commonly associated with different ages of users. Thus, for example, a sensor unit 100 suitable for use with a diaper to be provided for a newborn baby is unlikely to be suitable for use with a diaper to be provided for, for example, an adult male.

[0097] Therefore, the appropriate selection of the sensor unit 100 may depend closely on the absorbent article with which the sensor unit 100 is to be used. Thus, if multiple different absorbent articles are provided in any particular situation, a corresponding multiple of the sensor units 100 may also be provided. Each type of sensor unit 100 to be used with a particular type of absorbent article 900 may differ in one or more characteristics from other sensor units 100 of a similar configuration. For example, the dimensions, particularly the length, of the flexible substrate 120 and / or the positions and dimensions of the plates 111, 112, 113, 114 may differ. Furthermore, the electrical characteristics of the sensor unit 100, such as the capacitance or impedance measured in free space, may differ from other sensor units 100 of a similar configuration.

[0098] It is important to note that the sensor unit 100 shown in Figure 2 cannot monitor the absorption state of an absorbent article by itself. To enable the sensor unit 100 to monitor the absorption state of an absorbent article, as shown in Figure 3, the sensor unit 100 is combined with a data logging unit 200 such that the data logging unit 200 can provide electrical signals to the sensor unit 100 and measure changes in the electrical properties of the sensor unit 100.

[0099] For example, in the configuration of Figure 3, the data logging unit may be configured to measure the potential between pairs of plates 111, 112, 113, 114 by means of pads 151, 152, 153, 154 provided on terminal area 140. An exemplary configuration of data logging unit 200 is shown in Figure 4.

[0100] The data logging unit 200 shown in FIG. 4 includes an enclosure 210 that contains the data logging electronics described below.

[0101] Terminals 231, 232, 233, and 234 are provided in terminal region 220 of enclosure 210 to correspond to pads 151, 152, 153, and 154 of sensor unit 100 shown in Fig. 2. Terminals 231, 232, 233, and 234 may be provided, for example, as spring terminals. Such spring terminals may be formed as flexible conductor plates that protrude upward from terminal region 220 of enclosure 210 and form good electrical contact with conductors pressed against the surface of enclosure 210 on which terminal region 220 is formed.

[0102] Such terminal configurations are illustrative only, and other terminal configurations known to those skilled in the art may be substituted for the spring terminals depending on their suitability for a particular configuration. Such other terminal configurations include, for example, mezzanine connectors, plug / socket connectors, registered jack or modular connectors, pogo pin connectors, tip / ring / sleeve connectors, D-sub connectors, DIN connectors, or other terminal or connector types known in the art. Where such connectors are male and female, either the male or female part may be provided on the data logging unit 200, and the other of the male or female part may be provided on the sensor unit 100. Such terminal configurations may function to physically engage and electrically connect the data logging unit 200 and the sensor unit 100 when locking or other securement variants of such connectors are provided.

[0103] Terminal area 220 corresponds to terminal area 140 formed on sensor unit 100 in that the number and locations of terminals 231, 232, 233, 234 formed in terminal area 220 of datalog 200 correspond to the number and locations of pads 151, 152, 153, 154 of sensor unit 100. Thus, when terminal area 140 of sensor unit 100 is placed in contact with terminal area 220 of datalogging unit 200, datalogging unit 200 may provide and measure electrical signals associated with plates 111, 112, 113, 114 by terminals 231, 232, 233, 234 to perform measurements by sensor unit 100.

[0104] To secure the terminal area 140 of the sensor unit 100 in contact with the terminal area 220 of the data logging unit 200, the data logging unit 200 is provided with an engaging element, here a clamp plate 250, having protrusions (not shown) that are press-fit into holes 241, 242 formed in the enclosure 210. This configuration is shown in Figure 5. The press-fit allows the clamp plate 250 to apply force to the terminal area 220 and secure the interposed sensor strip.

[0105] To contact and secure the terminal area 140 of the sensor unit 100 to the terminal area 220 of the data logging unit 200, the configuration shown in FIG. 6 may be employed, in which the terminal area 140 of the sensor unit 100 is placed in contact with the terminal area 220, thereby aligning the terminals 231, 232, 233, 234 of the data logging unit 200 with the pads 151, 152, 153, 154 of the sensor unit 100.

[0106] In that case, clamping plate 250 is mounted to enclosure 210 such that protrusions on clamping plate 250 engage holes (241, 242) in enclosure 210. The final configuration is shown in Figure 7, where clamping plate 250 secures terminal area 140 of sensor unit 100 in contact with terminal area 220 of enclosure 210, thereby properly securing and connecting sensor unit 100 to data logging unit 200, thereby enabling data logging unit 200 to reliably transmit and retrieve signals to and from plates 111, 112, 113, 114 of sensor unit 100.

[0107] In order to correctly interpret the signals received from the sensor units 100, it is necessary to have information about the sensor units 100 connected to the data logging unit 200. In particular, different arrangements of the plates and / or different dimensions of the sensor units 100 will cause different changes in impedance under different conditions in the absorbent article in which the sensor units 100 are provided.

[0108] However, the configuration of data logging unit 200 shown in FIG. 5, and particularly the configuration of terminal area 220 with associated terminals 231, 232, 233, 234, allows a variety of sensor units 100 to be used in conjunction with data logging unit 200, including pads 151, 152, 153, 154 with similar configurations within terminal area 140, but each having plates 111, 112, 113, 114 with different configurations.

[0109] It is possible for a user, caregiver, or system operator to manually record which sensors 100 are associated with which particular data logging unit 200, so that this information can be used to interpret results from the data logging unit. However, it is advantageous if the data logging unit 200 can obtain information about the sensor unit 100 to which it is connected, so that this information is immediately available and can be used in further automated data processing operations and to avoid errors.

[0110] Thus, the data logging unit 200 implements a method for identifying the sensor unit 100 as further described below with respect to FIGS.

[0111] Within the enclosure 210 of the data logging unit 200 is provided a measurement unit MEAS, shown diagrammatically in FIG. 8 as part of the overall data logging unit 200 .

[0112] The measurement unit MEAS includes a microcontroller MC having a plurality of analog measurement terminals A0-A15 and a plurality of digital detection terminals D0-D7. The microcontroller MC is powered by a power supply PWR and selects one of the analog detection terminals A0-A15 and the digital terminals D0-D7, which are connected by conductive wires to a series of terminals 230 provided in a terminal area 220 of the enclosure 210.

[0113] Of these terminals, a subset of terminals 230a are connected to a subset of analog sense terminals A0-A15, a subset of terminals 230c are connected to digital terminals D0-D2, and one of terminals 230b is connected to ground GND of the measurement unit MEAS.

[0114] 8, digital terminals D0-D7 of microcontroller MC are connected to terminal 230c of terminal area 220 and are also individually connected to power supply PWR by respective pull-up resistors R1, R2, R3. Thus, in an open-circuit state, terminal 230c is maintained at a rising potential corresponding to a logic high, or binary one.

[0115] Terminals 230a are connected to analog sense terminals A0-A15 of the microcontroller MC and can be driven by potentials, allowing measurements of potentials, e.g., electrostatic or vibration potentials, to be made to measure simple or complex impedances between any of the terminals 230a, and are therefore referred to as measurement terminals.

[0116] Figure 9 shows a schematic diagram of the sensor unit 100, for cooperation with the measurement unit MEAS as shown in and described with respect to Figure 8. In the configuration shown in Figure 9, six sensing pads are provided: pads 111, 112, 113, 114, 115, 116. As mentioned above, the number and layout of pads may be varied depending on the application.

[0117] Pads 111, 112, 113, 114, 115, and 116 are connected by respective conductive traces to terminal area 140. Specifically, among the terminals present in terminal area 140, a set of terminals 150a are individually connected to respective pads 111, 112, 113, 114, 115, and 116. These terminals 150a, as well as terminal 230a, are referred to as measurement terminals.

[0118] The terminal 150b is provided on and connected to the ground plate 130.

[0119] Finally, a set of terminals 150c is provided, of which the first and third terminals in sequence are connected to ground and the second terminal is left unconnected, in other words this set is provided as an open circuit.

[0120] 9 is connected to the data logging unit 200 having the measurement unit MEAS shown in FIG. 8, the ground terminal 230b connects to the ground terminal 150b, thereby generating a reference ground from the sensor unit, the sense terminal 230a connects to the sense terminal 150a, thereby enabling the measurement unit MEAS to measure the impedance between a selected pair of pads 111, 112, 113, 114, 115, and 116, and the terminal 230c of the data logging unit 200 connects to the corresponding terminal 150c of the sensor unit 100, thereby causing the first and third terminals 1 and 3, which are connected to each other and to ground on the sensor unit side, to reach a potential relative to ground, in other words, a digital low or binary 0 potential. Meanwhile, the second of the terminals 230c, 150c is maintained at a digital high potential relative to the power supply PWR by the action of the pull-up resistor R2.

[0121] Among terminals 150c, the terminals that are connected to ground and the terminals that are left open determine potentials in terms of logic high or low potentials, and these potentials are detected at digital terminals D0-D7 of microcontroller MC. These terminals may be used to identify the characteristics of sensor strip 100 installed in data logging unit 200. Therefore, terminals 150c and terminal 230c are referred to as identification terminals.

[0122] 10, for ease of comparison with embodiments described below, a binary number, e.g., a binary triplet, may be coded by connecting the identification terminals 150c together or by certain of the identification terminals 150c. Any of the digital terminals D0-D7 may be used for this purpose.

[0123] To demonstrate this, FIG. 9 shows a modified configuration in which a subset of terminals D5-D7 are used to identify the sensor 100 instead of D0-D2.

[0124] 9 and 10, the first and third identification terminals 150c are connected together and to ground, while the second terminal is left open. This may correspond to the binary sequence 010, or 2 in decimal notation. Of course, in an alternative configuration, each of the first and third terminals could simply be connected independently to ground.

[0125] By connecting different terminals to each of the identification terminals 150c and connecting those terminals to ground, each different decimal number is coded as a sequence of three binary numbers. For example, the table below shows exemplary possibilities of how a sequence of three binary numbers presented on terminals 150c by connecting certain terminals to ground to represent a digital low (or binary number 0) and leaving certain terminals open to represent a digital high (or binary number 1) can correspond to different lengths of sensor strips suitable for different sizes and types of absorbent articles.

[0126] [Table 1]

[0127] Thus, with only three terminals, eight states of the sensor strip can be distinguished, including a state in which the strip is not connected. Furthermore, no separate components are required on the sensor unit 100 side, but rather the identification coding may be implemented simply by connecting specific terminals 150c together, for example, by conductive traces on the flexible substrate 120.

[0128] Thus, the sensor strip is more robust to deformation than situations where additional components are provided on the sensor strip on the sensor unit 100 to provide an identification signal.

[0129] 11, in which each of the identification terminals 230c of the terminal area 220 of the data logger 200 is individually connected to ground GND through a respective resistor R1, R2, R3, which resistors R1, R2, R3 act as pull-down resistors. Additionally, selected identification terminals 150c of the terminal area 140 of the sensor unit 100 are connected to each other and to a further terminal 150d, which corresponds to terminal 230d of the terminal area 220 of the data logging unit 200 that is connected to a power source. Thus, terminals 230d and 150d may be considered power source terminals.

[0130] As a result of pull-down resistors R1, R2, and R3, identification terminal 230c is maintained as a digital low (or binary 0) when in an open circuit state. However, when connected to each other and to identification terminal 150d, which is connected to power supply PWR of data logging unit 200 via power supply terminals 150c and 230d, the selected identification terminal 230c is set to a potential corresponding to a digital high (or binary 1).

[0131] Again, as with the alternative embodiment of FIG. 10, the selection of which terminals are connected to the power supply potential and which are left open circuit can be used to encode characteristics of the sensor 100 connected to the data logging unit 200.

[0132] 12, five digital terminals D3-D7 are connected to five identification terminals 230c on the terminal area 220 of the data logging unit 200, and each of these terminals is individually connected to the power supply PWR via a respective resistor R1, R2, R3, R4, R5. R1, R2, R3, R4, R5 thus operate in a pull-up configuration.

[0133] On the sensor unit 100 side, one selected terminal of the corresponding identification terminals 150c provided in the terminal area 140 of the sensor unit 100 is kept unconnected, while the remaining identification terminals 150c are connected to ground 130.

[0134] This configuration uses numeric coding rather than binary coding, with the order of the terminals 150c not connected to ground coding the type of connected sensor 100. Decoding the sensor type is simpler than the configuration of Figure 12, but more identification terminals 230c are required to enable differentiation between a given number of types of sensor units 100 compared to the binary-coded variants of Figures 10 and 11. For example, the embodiment of Figure 12 uses eight terminals, allowing eight types of sensor units 100 to be coded, whereas the variants of Figures 10 or 11 allow 2^8 (two to the power of eight), or in other words, 256 different configurations, to be coded using the eight identification terminals.

[0135] A further alternative embodiment is shown in FIG. 13, in which, rather than grounding all identification terminals 150c of the sensor unit 100 except for one identification terminal used to indicate the type of sensor unit 100 as in FIG. 12, in the embodiment of FIG. 13 all terminals 150c are left open circuited except for one terminal that is grounded and therefore used to indicate the characteristics of the attached sensor unit 100.

[0136] A further configuration is shown in Figure 14, in which, similar to the configuration of Figure 11, the power connection to the power supply PWR of the data logger 200 is made at power terminal 230d in terminal area 220 of the data logging unit 200. Power terminal 230d is connected to power terminal 150d in terminal area 140 on the sensor unit 100.

[0137] On the data logging unit side, the identification terminal 220c is connected to ground via resistors R1, R2, R3, R4, and R5, which act as pull-down resistors, while on the sensor unit side, selected ones of the identification terminals 150c are connected to the power supply terminal 150d via conductive traces, while the other identification terminals are left open. Thus, selected ones of the identification terminals 150c are set to a potential corresponding to a digital high, while the remaining identification terminals 150c are maintained at a digital low. Selecting the terminal set as a digital low encodes the characteristics of the sensor 100 being used.

[0138] A further variant corresponding to the configuration shown in Figure 14 is shown in Figure 15, except that all of the identification terminals 150c on the sensor unit side are connected to each other and connected to the power supply terminal 150d corresponding to a digital high, except for the terminals which are kept open, so that the type of sensor 100 connected is coded by selecting which terminals are kept open, corresponding to a digital low.

[0139] The above has been disclosed in terms of a power supply PWR for data logger 200. This may be a replaceable battery, a non-user replaceable battery, a rechargeable battery, a disposable battery, or any alternative power source that meets the supply needs of the data logging unit shown and described.

[0140] The enclosure 210 of the data logging unit 200 may be, for example, a plastic enclosure, which may be sealed or may be openable to allow for maintenance and adjustment, for example, replacement of the power supply.

[0141] While the above has been described with reference to identifying a sensor unit that measures the condition of an absorbent article by means of sensing plates that act as plates of a capacitor, thereby measuring an inductance related to the presence of liquid within the absorbent core of the absorbent article, the above disclosure is not limited to such configurations and may be used in connection with any type of sensor unit that may be used to measure the absorbent state of an absorbent article.

[0142] For example, it is envisioned that the disclosure described herein may equally be applied to sensors that may operate based on resistance, may respond to the presence of a particular chemical, or, in some cases, may be applied to an absorbent article by penetrating the absorbent core with a sensing element or other means that sensorily associates the sensing element with the absorbent core of the absorbent article.

[0143] Additionally, although disclosed with respect to diapers, the disclosure is not so limited and the technology herein may be applied, without limitation, to sensors for detecting the absorbency of other absorbent articles, such as absorbent pads, pant diapers, belt diapers, incontinence shields, wound dressings, sanitary napkins and other hygiene products.

[0144] In the above disclosure, the data logging unit may be a stand-alone data logging unit, equipped with a memory MR to store periodic measurements. These periodic measurements may later be downloaded from the data logger to a management console, such as a personal computer, to evaluate the absorbency pattern of the absorbent article over time. The data logging unit may include a data retrieval interface, such as a USB port, for downloading via a wired connection, or a short-range wireless data retrieval interface, such as a Bluetooth module, for downloading via a wireless configuration.

[0145] Alternatively, the data logging unit may measure the condition of the absorbent article and may temporarily retain information regarding the condition of the absorbent article in order to provide notification of changes in the condition of the absorbent article, for example by providing an audible (e.g., by a buzzer) or visible (e.g., by a light emitting diode, or LED) output signal from the data logging unit.

[0146] In another configuration, the data logging unit may be associated with a remote terminal, which may be a portable computing device such as a laptop, a smartphone, or may be a server or virtual server. The data logging unit may be connected to the remote terminal by a wireless link to transmit and provide measurements to the remote terminal periodically, as needed, or upon detection of a change in absorption status.

[0147] Such a configuration may be understood by reference to FIG. 16, in which in addition to a measurement unit MEAS, a memory controller MCO, a memory MRY, and a transmission controller TX, a data logging unit is provided.

[0148] 16, the data logger 200 may periodically measure the absorbency of the absorbent article via the sensor unit 100. The results of this measurement may be recorded in the memory MRY by the memory controller MCO. In that case, according to a predetermined schedule or when a predetermined number of measurements have been taken, the memory controller MCO may transmit the information stored in the memory MRY to be transmitted via the transmitting controller TX over the wireless link LNK to the receiving controller RX of the remote terminal 300.

[0149] The remote terminal 300 comprises a central processing unit CPU coupled to a database DB and a user interface UI. Data received from the radio link LNK by the receiving controller RX may be stored in the database DB by the central processing unit CPU, and this information may be retrieved by the user interface UI.

[0150] The remote terminal 300 may be associated with a single data logging unit 200, or may be associated with multiple data logging units 200. In the former case, the user interface controller UI may enable a user to query the database DB to evaluate historical data regarding the absorption status of absorbent articles associated with the data logger 200. In the latter case, the user interface controller UI may enable a user to query the database DB to compare and analyze results from multiple data loggers 200 associated with the remote terminal 200.

[0151] 16, the data logger 200 and the remote terminal 300 form a management system 400. In the management system 400, the memory MRY may comprise a look-up table that enables the measurement controller MCO to determine the characteristics of the sensor unit 100 using the methods disclosed herein, whereby the characteristics of the sensor unit 100 may be stored in the memory MRY together with the measurement results and may be transmitted together with the measurement results to the remote terminal 300 via the wireless link LNK.

[0152] Alternatively, the measurement unit MEAS may simply store the measurement result of the identification terminal 230c in the memory MRY, which may be transmitted together with the measurement value via the wireless link LNK. In such a configuration, the database DB of the remote terminal 300 may contain a look-up table that allows decoding of the identification information supplied to the identification terminal 230c to identify the characteristics of the sensor unit 100 associated with the measurement.

[0153] In each of the above configurations, the measurement unit MEAS can determine a characteristic of the sensor unit 100, and each measurement of the hygiene condition of the absorbent article is made using the sensor unit 100. In an alternative configuration, the determination may be made once after the sensor unit 100 is connected to the data logger unit 200, which can be detected by a change in the state of one of the identification terminals 230c.

[0154] While the above disclosure has been made with respect to particular examples, those skilled in the art will appreciate that substantial modifications and variations may be made without departing from the various concepts in the advantageous configurations, devices, methods, and systems disclosed and described herein. It is therefore to be understood that the present invention is not limited to the embodiments shown and described herein, but should be determined with reference to the appended claims. [Explanation of symbols]

[0155] 100 Sensor Unit, Sensor 111, 112, 113, 114, 115, 116 Detection plates 120 Flexible PCB 130 Ground plate, ground 140 Terminal area 150a terminal, detection terminal 150b terminal, ground terminal 150c terminal, identification terminal 150d terminal, power terminal 151, 152, 153, 154 Conductive pads, pads 161, 162, 163, 164 Conductive traces 200 Data Logging Units, Data Loggers, Remote Terminals 210 Enclosure 220 Terminal area 230 terminal 230a terminal, detection terminal 230b terminal, ground terminal 230c terminal, identification terminal 230d terminal, power terminal Terminals 231, 232, 233, and 234 241, 242 holes 250 clamp plate 300 Remote Terminal 400 Management System 900 Absorbent articles, diapers 910 absorbent core 920 Front waist 921 Tab part 922 Tab part 924 Tab part 925 Tab part 930 Posterior lumbar region A0~A15 Analog measurement terminals, analog detection terminals D0~D7 Digital terminals, digital detection terminals GND Ground LNK Wireless Link MC Microcontroller MCO Memory Controller MEAS measuring unit MRY Memory PWR power supply R1, R2, R3, R4, R5 Resistors, pull-up resistors RX Receive Controller TX Transmit Controller UI User Interface

Claims

1. 1. A method for identifying a sensor unit for an absorbent article by a data logger unit, comprising: the sensor unit comprises a sensor-side terminal portion and a plurality of detection elements electrically connected to at least one measurement terminal of the sensor-side terminal portion, the detection elements being provided on a flexible substrate of the sensor unit, the flexible substrate extending along the longitudinal direction of an elongated absorbent core of the absorbent article, the detection elements being composed of a plurality of pairs of elongated conductive plates along the longitudinal direction, the conductive plates of each pair being arranged opposite each other in the short-side direction of the flexible substrate, and the pairs of conductive plates being arranged at intervals along the longitudinal direction; the data logger unit includes a logger-side terminal section and a measurement module electrically connected to at least one detection terminal of the logger-side terminal section; the sensor-side terminal portion engages with the logger-side terminal portion, thereby electrically connecting the terminals of the sensor-side terminal portion to corresponding terminals of the logger-side sensor portion; the data logger unit is configured to perform electrical measurements of the plurality of sensing elements via the at least one measurement terminal of the sensor-side terminal portion and the at least one measurement terminal of the logger-side terminal portion; the data logger unit has a plurality of identification terminals at the logger terminal section electrically connected to the measurement module; the sensor-side terminal portion has a plurality of identification terminals at the sensor-side terminal portion, the measurement module performs electrical measurements on the identification terminals of the logger-side terminal section to identify characteristics of the sensor unit; The method, wherein the characteristic of the sensor unit is coded by a potential of the identification terminal of the sensor-side terminal portion using binary coding, which encodes a numerical value indicating the characteristic in binary.

2. The sensor-side terminal portion has a reference terminal, The logger-side terminal unit has a reference terminal, The measurement module supplies a reference potential to the reference terminal of the logger-side terminal unit, at least one of the identification terminals of the sensor-side terminal portion is electrically connected to the reference terminal of the sensor-side terminal portion via a conductor of the sensor unit; The method of claim 1 , wherein the characteristic of the sensor unit is coded by a potential at each of the identification terminals of the sensor-side terminal portion relative to the reference potential.

3. 3. The method of claim 2, wherein a resistor of the data logger unit is electrically connected between each identification terminal of the sensor-side terminal portion and a conductor of the data logger unit maintained at a potential supplied by the measurement module that is different from the reference potential.

4. 4. The method according to claim 2 or 3, wherein one or more of the identification terminals of the sensor-side terminal section are electrically connected to the reference terminal of the sensor-side terminal section by a conductor of the sensor unit, and the remaining identification terminals of the sensor-side terminal section are not electrically connected to the reference terminal of the sensor-side terminal section.

5. 5. The method of claim 2, 3, or 4, wherein the reference potential is the ground potential of the measurement module.

6. the reference terminal of the sensor-side terminal portion is a ground terminal, the reference terminal of the logger-side terminal portion is a ground terminal connected to the ground of the measurement module by a conductor of the data logger unit; The method of claim 5 , wherein one or more of the identification terminals of the sensor-side terminal portion are electrically connected to the reference terminal of the sensor-side terminal portion by a conductor of the sensor unit.

7. 5. The method of claim 2, 3, or 4, wherein the reference potential is a potential different from the ground potential of the measurement module.

8. the reference terminal of the sensor-side terminal portion is a power supply terminal, The reference terminal of the logger-side terminal unit is a power supply terminal, the power supply terminal of the logger-side terminal section is electrically connected to a potential supplied by the measurement module by a conductor of the data logger unit; 5. The method of claim 2, 3, or 4, wherein one or more of the identification terminals of the sensor side terminal portion are electrically connected to each other and to the power supply terminal of the sensor side terminal portion by a conductor of the sensor unit.

9. 9. The method of claim 1, wherein the characteristic of the sensor unit is determined by identifying a single terminal among the identified terminals of the logger terminal section as a terminal having a reference potential, and the identified terminal correlates with the characteristic.

10. 9. The method of claim 2, wherein the characteristic of the sensor unit is determined by identifying a set of identified terminals of the logger terminal section as terminals having the reference potential, and the set of identified terminals correlates with the characteristic.

11. 11. The method of claim 2, wherein the potentials of the identification terminals of the logger terminal section define a sequence of binary numbers, and the data logger unit decodes a value correlating with the characteristic from the sequence of binary numbers.

12. The method of claim 1 , wherein the sensing element is disposed on one surface of a flexible substrate and a conductive region is disposed on the other surface of the flexible substrate so as to be located below the sensing element.

13. The method according to claim 6 , wherein the conductive plate is connected to the ground potential of the measurement module via the ground terminal of the sensor-side terminal portion.

14. 14. The method of claim 1, wherein the data logger unit is removably attached to the sensor unit before the measurement module performs the electrical measurements.

15. 15. The method of claim 14, wherein after the measurement module performs the electrical measurements, the data logger unit is detached from the sensor unit and attached to another sensor unit.

16. a data logger unit for receiving data from a sensor unit provided in an absorbent article, a logger-side terminal section and a measurement module electrically connected to at least one measurement terminal of the logger-side terminal section, wherein the logger-side terminal section engages with a sensor-side terminal section of the sensor unit, thereby connecting the sensor unit and the data logger unit; the measurement module is arranged to perform electrical measurements via the at least one measurement terminal of the logger-side terminal portion; the data logger unit has a plurality of identification terminals at the logger terminal section electrically connected to the measurement module; the measurement module is configured to perform measurements on the plurality of identification terminals to identify characteristics of the sensor unit; the characteristic of the sensor unit is coded in the potential of the identification terminal by binary coding, which encodes a value indicating the characteristic in binary; a data logger unit, the data logger unit comprising: a sensor side terminal portion; and a plurality of detecting elements electrically connected to at least one measurement terminal of the sensor side terminal portion, the detecting elements being provided on a flexible substrate of the sensor unit, the flexible substrate extending along the longitudinal direction of an elongated absorbent core of an absorbent article, the detecting elements being composed of a plurality of pairs of elongated conductive plates along the longitudinal direction, the conductive plates of each pair being arranged opposite each other in the short direction of the flexible substrate, and the pairs of conductive plates being arranged at intervals along the longitudinal direction.

17. The logger-side terminal unit has a reference terminal, The measurement module is configured to supply a reference potential to the reference terminal of the logger-side terminal unit, 17. The data logger unit according to claim 16, wherein the characteristics of the sensor unit are coded by a potential at each of the identification terminals of the logger-side terminal section relative to the reference potential.

18. 18. The data logger unit of claim 17, wherein a resistor of the data logger unit is electrically connected between each identification terminal of the logger side terminal portion and a conductor of the data logger unit that is maintained at a potential supplied by the measurement module that is different from the reference potential.

19. 19. A data logger unit according to claim 17 or 18, wherein the reference potential is the ground potential of the measurement module.

20. The reference terminal of the logger-side terminal unit is a ground terminal, 20. The data logger unit of claim 19, wherein the ground terminal is connected to the ground of the measurement module by a conductor of the data logger unit.

21. 19. A data logger unit according to claim 17 or 18, wherein the reference potential is a potential different from the ground potential of the measurement module.

22. The reference terminal of the logger-side terminal unit is a power supply terminal, 19. A data logger unit according to claim 17 or 18, wherein the power supply terminals are electrically connected to a potential supplied by the measurement module by conductors of the data logger unit.

23. the reference terminal of the logger-side terminal unit is a ground terminal, 19. The data logger unit according to claim 17, wherein the ground terminal of the logger-side terminal portion is connected to the ground potential of the measurement module by a conductor of the data logger unit.

24. 23. The data logger unit of claim 22, wherein the characteristic of the sensor unit is determined by identifying a single terminal among the identified terminals of the logger side terminal section as the terminal having the reference potential, and the identified terminal correlates with the characteristic.

25. 25. The data logger unit of claim 21, wherein the measurement module is configured to determine the characteristic of the sensor unit by identifying a set of identified terminals of the logger terminal section as terminals having the reference potential, the set of identified terminals correlating with the characteristic.

26. 17. A data logger unit as claimed in claim 17 and any one of claims 18 to 25 depending on claim 17, wherein the potentials of the identification terminals define a sequence of binary numbers, and the data logger unit decodes a value correlating with the characteristic from the sequence of binary numbers.

27. 27. A data logger unit according to any one of claims 16 to 26, wherein the data logger unit is removably attachable to the sensor unit.

28. 28. The data logger unit of any one of claims 16 to 27, wherein the data logger unit is removably attachable to the absorbent article.

29. 29. A data logger unit according to any one of claims 16 to 28, wherein the measurement module is adapted to repeat taking the electrical measurements after the data logger unit is removed from the sensor unit and attached to another sensor unit.

30. a sensor unit for an absorbent article connected to a data logger unit for determining the hygiene status of the absorbent article, a sensor-side terminal portion and a plurality of detection elements electrically connected to at least one measurement terminal of the sensor-side terminal portion, the detection elements being provided on a flexible substrate of the sensor unit, the flexible substrate extending along the longitudinal direction of an elongated absorbent core of the absorbent article, the detection elements being composed of a plurality of pairs of elongated conductive plates along the longitudinal direction, the conductive plates of each pair being arranged opposite each other in the short direction of the flexible substrate, and the pairs of conductive plates being arranged at intervals along the longitudinal direction; the sensor-side terminal portion engages with the logger-side terminal portion of the data logger unit, thereby connecting the sensor unit and the data logger unit; the sensor-side terminal portion has a plurality of identification terminals at the sensor-side terminal portion, the identification terminals of the sensor-side terminal section are configured to indicate characteristics of the sensor unit by electrical measurement of the plurality of identification terminals; A sensor unit in which the characteristics of the sensor unit are coded by the potential of the identification terminal of the sensor side terminal portion when connected to the data logger unit using binary coding, which encodes a numerical value indicating the characteristics in binary.

31. The sensor-side terminal portion has a reference terminal, at least one of the identification terminals of the sensor-side terminal portion is electrically connected to the reference terminal of the sensor-side terminal portion via a conductor of the sensor unit; The sensor unit according to claim 30 , wherein the characteristics of the sensor unit are coded by a potential at each of the identification terminals of the sensor-side terminal portion relative to a reference potential of the reference terminal.

32. 32. The sensor unit of claim 31 , wherein one or more of the identification terminals of the sensor side terminal portion are electrically connected to the reference terminal of the sensor side terminal portion by a conductor of the sensor unit, and the remaining identification terminals of the sensor side terminal portion are not electrically connected to the reference terminal of the sensor side terminal portion.

33. the reference terminal of the sensor-side terminal portion is a ground terminal, 33. The sensor unit of claim 31 or 32, wherein one or more of the identification terminals of the sensor side terminal portion are electrically connected to each other and to the ground terminal of the sensor side terminal portion by a conductor of the sensor unit.

34. the reference terminal of the sensor-side terminal portion is a power supply terminal, 34. The sensor unit of claim 31, 32, or 33, wherein one or more of the identification terminals of the sensor side terminal portion are electrically connected to each other and to the power supply terminal of the sensor side terminal portion by a conductor of the sensor unit.

35. The sensor unit according to claim 34 , wherein the sensor-side terminal portion of the reference terminal is a ground terminal.

36. 36. A sensor unit according to any one of claims 31 to 35, wherein the characteristic of the sensor unit is determined by identifying a single terminal among the sensor identification terminals of the sensor side terminal portion as the terminal having the reference potential, and the identified terminal correlates with the characteristic.

37. 36. The sensor unit of claim 31, wherein the characteristic of the sensor unit is determined by identifying a plurality of terminals of the sensor side terminal section among the identified terminals of the sensor side terminal section as terminals having the reference potential, and a set of the identified terminals correlates with the characteristic.

38. A sensor unit described in claim 30 and any one of claims 31 to 37 dependent on claim 30, wherein the potential of the identification terminal of the sensor side terminal portion defines a sequence of binary numbers, and the sequence of binary numbers is decoded into a value correlated with the characteristic.

39. 35. The sensor unit of claim 34, wherein the sensing element is arranged on one surface of the flexible substrate, and the conductive region is arranged so that the other surface of the flexible substrate is positioned on the side where one or more pairs of the conductive plates are positioned so as to be positioned below the sensing element.

40. The sensor unit according to claim 35 , wherein the conductive plate is connected to the ground terminal of the sensor-side terminal portion.

41. 41. The sensor unit of any one of claims 30 to 40, wherein the sensor unit is removably attachable to the data logger unit.

42. 42. The sensor unit of any one of claims 30 to 41, wherein the sensor unit is removably attachable to the absorbent article.

43. 43. The sensor unit of any one of claims 30 to 42, wherein the sensor unit is configured to contactlessly detect the presence of bodily fluid in an absorbent article in proximity to the sensor unit.

44. 44. A plurality of interchangeable sensor units comprising the sensor unit according to any one of claims 30 to 43, wherein each of the sensor units has a common configuration of a sensor-side terminal portion adapted to engage with a logger-side terminal portion of a common data logger unit, the characteristic being a characteristic that differs between the interchangeable sensor units, and the characteristic being uniquely specified by the potential of the identification terminal of the sensor-side terminal portion of each sensor unit when connected to the data logger unit.

45. 45. The plurality of replaceable sensor units of claim 44, wherein the characteristic is a length in an extension direction of the sensor unit.

46. 45. The plurality of interchangeable sensor units of claim 44, wherein the characteristic is an electrical characteristic associated with the plurality of sensing elements.

47. 47. The multiple replaceable sensor unit of claim 46, wherein the multiple sensing elements comprise two elongated sensing elements arranged parallel to one another, and the characteristic is a capacitance between the sensing elements.

48. 45. The multiple replaceable sensor unit of claim 44, wherein the characteristic is a dimension associated with the multiple sensing elements.

49. 49. A plurality of interchangeable sensor units according to any one of claims 44 to 48, adapted to be removably attached to the common data logger unit.

50. An absorbent article management system, comprising: A data logger unit according to any one of claims 16 to 29; 44. The sensor unit according to any one of claims 30 to 43, wherein the sensor unit is provided on an absorbent article such that the plurality of sensing elements are arranged to determine the hygiene state of the absorbent article; Equipped with The data logger unit is adapted to carry out the method of any one of claims 1 to 15 when the data logger unit is connected to the sensor unit, The data logger unit periodically performs electrical measurements of the multiple detection elements via the at least one measurement terminal of the sensor side terminal portion and the at least one measurement terminal of the logger side terminal portion, and associates information regarding the results of the electrical measurements with information regarding the potential of the identification terminal of the sensor side terminal portion to identify the characteristics of the sensor unit.

51. 51. The absorbent article management system of claim 50, wherein the data logger unit comprises a data storage unit, and the data logger unit is configured to store information relating to the results of the electrical measurements in association with information identifying the characteristics of the sensor unit.

52. 52. An absorbent article management system as described in claim 50 or 51, further comprising a remote terminal, wherein the data logger unit comprises a communication unit configured to transmit data to the remote terminal, and the communication unit is configured to transmit information regarding the results of the electrical measurement to the remote terminal in association with information for identifying the characteristics of the sensor unit.

53. 53. The absorbent article management system of claim 52, wherein the remote terminal comprises a database configured to store information relating to the results of the electrical measurements in association with information identifying the characteristics of the sensor unit.

54. The absorbent article management system according to any one of claims 50 to 53, wherein the data logger unit is adapted to decode the potential of the identification terminal of the logger side terminal portion to provide information relating to the characteristics.

55. The absorbent article management system according to claim 52 or 53, wherein the remote terminal is configured to decode the potential of the identification terminal of the logger side terminal portion to provide information relating to the characteristics.

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