Capacitive double-sided sensing film and related products, apparatus, and methods

Abstract

The present invention provides a capacitive double-sided detection film comprising a plastic film substrate and first and second detection electrodes installed on the upper and lower surfaces of the plastic film substrate, respectively. The first and second detection electrodes each include first and second metal vapor-deposited layers, which are the same size as the plastic film substrate and are stacked to form a parallel plate capacitor, generating a first capacitance for providing information about the area of ​​the detection film. When excrement permeates at least a portion of both the upper and lower surfaces of the detection film and connects them, a second capacitance is generated between the first and second detection electrodes, positively correlated with the permeation area, for providing information about the state of excrement permeation. The present invention further provides a smart diaper including the capacitive double-sided detection film, a wetness monitoring device for the smart diaper, a method for creating a capacitive double-sided detection film, and a method for achieving saturation detection and differentiation of urine and feces within the smart diaper.

Description

Technical Field

[0001] This application claims the priority of the patent application with application number 202310279525.2, titled "Electric Double-Layer Capacitance Type Thin Film Sensor and Related Products, Devices and Methods", filed with the Chinese Patent Office on March 22, 2023, and all of the above content is incorporated herein by reference.

[0002] The present invention relates to a detection film, particularly a capacitance type double-sided detection film for realizing the detection of excrement, its manufacturing method, and related applications.

Background Art

[0003] The detection film referred to in this application is a film with a wetness detection function and can be used as a raw material for the production of smart diapers. When it is sandwiched inside the diaper during diaper production, the diaper can be transformed into a smart diaper that can provide quantified wetness state information and excrement information, which has practical significance for the scientific use and replacement of diapers and is an important development direction for diapers.

[0004] In terms of the prior art, Chinese Patent Publication No. 114324502B discloses a capacitance type sensor film and related smart diapers and detection system devices. The sensor film (detection film) includes a metal film electrode (detection electrode), a flexible substrate, and a waterproof protective layer. Among them, the detection electrode is installed on the flexible substrate, and the waterproof protective layer covers and protects the detection electrode. When the detection film is infiltrated with a liquid containing an electrolyte, a wetness detection function based on electrolytic capacitance can be realized.

[0005] While the above-described conventional technology can achieve quantified wetness detection, the two electrodes are arranged in parallel on the same surface of the flexible substrate, and there is a gap (margin) between the two electrodes. In such a structure, the width of the detection film increases, and when the detection film is placed between the surface layer and the absorbent layer of a disposable diaper, it has a certain effect on the penetration of urine from the surface layer to the absorbent layer. At the same time, because there is no overlap between the two electrodes in the above-described conventional technology, the standard parameters of the detection film cannot be determined by detecting the initial capacitance between the electrodes, making it impossible to perform adaptive operations or damage compensation, and also failing to solve the capacitance interference problem caused by wetness on one side or contact with one side of the human body.

[0006] Furthermore, the conventional detection films described above cannot be arbitrarily cut and used as needed because they destroy the structural relationship between the two electrodes. In addition, the gap between the electrodes usually needs to be created by a watermarking process (e.g., laser watermarking, chemical etching, aluminum cleaning), but watermarking processes usually significantly increase production costs. For example, a vacuum-plated aluminum film with watermarking usually costs several times more than an aluminum-plated film without watermarking.

[0007] Furthermore, since the electrodes of the conventional technology described above are protected on both the top and bottom surfaces by a flexible substrate and a waterproof protective layer, the connection end of the detection device cannot make face-to-face contact and electrical connection with the electrode. If it is desired to make an electrical connection using the exposed portion without the waterproof protective layer, tracking positioning must be performed on the exposed portion during production, and the exposed portion must be placed in a specific position on the disposable diaper. This will undoubtedly increase production and usage costs and reduce the versatility of the detection film.

[0008] The shortcomings of the conventional technology described above need to be addressed by new technological methods. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Chinese Patent Publication Number CN114324502B [Overview of the Initiative]

[0010] The technical problems that this invention aims to solve are a capacitive double-sided sensing film and a method for producing the same, which has low internal resistance, excellent flexibility, is compatible with conventional vacuum deposition processes, allows for a reduction in the width of the sensing film, eliminates single-sided interference, is convenient for cutting and use, allows for electrical connections at any position, and can provide its own standard parameter information and wet / soaked state information; and a smart diaper including the sensing film, a monitoring system device, and a method for realizing saturation detection and urine / feces classification of the smart diaper.

[0011] To solve the above technical problems, first, in an embodiment of the present invention, a capacitive double-sided detection film is provided for use in detecting excrement, comprising a plastic film substrate and a first detection electrode and a second detection electrode installed on the upper and lower surfaces of the plastic film substrate, respectively, wherein the first detection electrode and the second detection electrode each include a first metal electrode and a second metal electrode for reducing the internal resistance of the electrode and the capacitance value between the electrode and the liquid, thereby reducing the time constant of the detection circuit, wherein the first metal electrode and the second metal electrode each include a first metal deposition layer and a second metal deposition layer for reducing the thickness of the electrode by a metal deposition process to provide the necessary flexibility, wherein the metal deposition layer is a completely integrated vacuum deposition layer, plus The plastic film substrate is completely coated on both its upper and lower surfaces, is compatible with conventional vacuum deposition processes, and reduces costs by eliminating the need to create circuits with specific shapes and patterns. The first and second metal deposition layers are located on both the upper and lower surfaces of the plastic film substrate, overlapping each other. This reduces the width of the capacitive double-sided sensing film and prevents capacitive interference caused by one-sided wetting and one-sided contact with the human body. The first and second metal deposition layers and the plastic film substrate are the same size and overlapping each other, making them convenient to cut and use. Regardless of how they are cut, the size matching and the structural relationship of the layers remain unchanged. The first and second detection electrodes, together with a plastic film substrate, form a parallel plate capacitor to provide information related to the area of ​​the capacitive double-sided detection film, perform adaptive operations by determining the range and scope of the signal output, and generate a first capacitance to facilitate damage compensation. When electrolyte-containing excrement infiltrates at least a portion of both the upper and lower surfaces of the capacitive double-sided detection film and connects to form a second capacitance that is positively correlated with the infiltration area, providing information about the state in which the capacitive double-sided detection film is infiltrated by the excrement.

[0012] Of these, the magnitude of the first capacitance is directly proportional to the area and dielectric constant of the plastic film substrate, inversely proportional to the thickness of the plastic film substrate, and independent of the shape and immersion state of the capacitive double-sided sensing film. The second capacitance is the capacitance generated between the first detection electrode and the excrement, and is the series value of the capacitance generated between the second detection electrode and the excrement. By analyzing the magnitude and law of change of this series value, it is used to determine the excrement immersion state of the capacitive double-sided detection film and the properties of the excrement. The metal vapor deposition layer does not contain any coating layers or pores that would affect its conductivity, and in order to enhance the versatility and convenience of the capacitive double-sided detection film, it is possible to make an electrical connection to a capacitance detection device at any position.

[0013] This includes a semiconductor coating layer or insulating coating layer used to coat the outer surface of any of the metal vapor-deposited layers, thereby reducing the capacitance value between the corresponding metal vapor-deposited layer and the excrement, and thereby realizing a directional excrement detection function that emphasizes the direction of the coating layer, or This includes a conductive coating layer having a microporous structure or a rough surface, which is used to achieve a directional excrement detection function focused on the uncoated layer direction by increasing the capacitance value between the corresponding metal vapor-deposited layer and the excrement, by coating the outer surface of one of the metal vapor-deposited layers, or This includes a partially thickened conductive layer used to increase the thickness of a portion of the conductive material covering a specific location on the outer surface of any of the metal vapor-deposited layers, thereby providing further conductivity in the thickness direction and improving the reliability of the electrical connection when an electrical connection is made between the portion and the metal vapor-deposited layer using a metal needle-tip drilling method.

[0014] Of these, the semiconductor coating layer includes a metal oxide vapor deposition layer, and the insulating coating layer includes an insulating material coating layer or vapor deposition layer. Both are used to prevent charged ions in the excrement from directly contacting the outer surface of the metal vapor deposition layer and reducing the generation of a second capacitance. The conductive coating layer includes a carbon-based conductive ink coating layer or graphene vapor deposition layer to increase the generation of a second capacitance by increasing the surface area in contact with the excrement, and the partially thickened conductive layer includes a conductive ink coating layer or printed layer.

[0015] Of these, the metal vapor deposition layer includes a vacuum aluminum plating layer, the plastic film substrate includes a polyester film, polyethylene film, polypropylene film, or polyimide film, and the excrement includes urine, feces, sweat, or blood. In another aspect, embodiments of the present invention provide a smart disposable diaper comprising a capacitive double-sided sensing film and a disposable absorbent material, the disposable absorbent material comprising a surface layer, an absorbent layer and a base film, which are layered and bonded in that order, and the capacitive double-sided sensing film is placed on the surface layer or between the surface layer and the base film, and provides information regarding the soaking state of the disposable absorbent material by a second capacitance. Of these, the area or length of the capacitive double-sided detection film corresponds to the model number specifications or length of the disposable absorbent material. By detecting the first capacitance, model number specifications or length information of the disposable absorbent material is obtained, which is used to facilitate adaptive operation.

[0016] In this configuration, the capacitive double-sided detection film is placed between the surface layer and the base film, and the area between the capacitive double-sided detection film and the surface layer or base film includes an adhesive-free region, facilitating electrical connection between one or both sides of the capacitive double-sided detection film and the connection terminal of the capacitance detection device, and is used to realize the excrement detection function of disposable absorbent products by the capacitance detection device, or The surface layer or base film includes an opening, exposing one or both sides of the capacitive double-sided detection film through the opening, enabling electrical connection to the connection terminal of the capacitance detection device, and realizing the excrement detection function of disposable absorbent products through the capacitance detection device. In this configuration, the capacitive double-sided detection film is placed between the surface layer and the absorption layer. The absorption layer contains a polymer absorbent material, which gradually absorbs and traps moisture entering from the surface layer, thereby gradually drying the surface layer. This causes the surface layer to undergo a change from wet to dry once during each urination process, while simultaneously causing the second capacitance to undergo a change from large to small, and, The rate at which the second capacitance changes from large to small is related to the saturation of the absorption layer. The higher the saturation, the slower the rate at which the second capacitance changes from large to small. Based on this rate, the saturation of the absorption layer can be determined, and When the excrement is soft, it is difficult for the absorbent layer to absorb it, so the second capacitance value remains high for a long time. Based on this characteristic, it can be determined that the excrement is soft.

[0017] In another aspect, an embodiment of the present invention provides a smart diaper state monitoring device including a smart diaper and a capacitance detection device, the capacitance detection device including at least two connection terminals, which are electrically connected to a first detection electrode and a second detection electrode of a capacitive double-sided detection film, respectively, and realize a waste state monitoring function.

[0018] This includes a wireless transmitter and a wireless receiver for transmitting and receiving information about the excrement status of smart diapers, thereby enabling wireless status monitoring and status display functions for smart diapers.

[0019] Furthermore, embodiments of the present invention also provide a method for creating a capacitive double-sided detection film, which includes the following steps.

[0020] Adopting any one of a polyester film, a polyethylene film, a polypropylene film or a polyimide film as a plastic film base material, wherein the plastic film base material is in the form of a wide-width roll material at this time, Adopting any one of aluminum, copper, gold, silver, zinc or chromium as a metal material to be vapor-deposited, Vapor-depositing a metal material on one side of the plastic film base material by vacuum vapor deposition technology to form a first metal vapor deposition layer, and creating a single-sided metal vapor deposition film, and then winding it up to form a wide-width single-sided metal vapor deposition film roll material, Vapor-depositing a metal material on the non-coated surface of the single-sided metal vapor deposition film roll material by vacuum vapor deposition technology to form a second metal vapor deposition layer, and creating a double-sided metal vapor deposition film, and then winding it up to form a wide-width double-sided metal vapor deposition film roll material, Cutting the wide-width double-sided metal vapor deposition film roll material into the required width and winding it up to make several narrow-width double-sided metal vapor deposition film roll materials. At this time, both upper and lower surfaces of the plastic film base material are completely covered with the metal material, the sizes and shapes of the first metal vapor deposition layer, the second metal vapor deposition layer and the plastic film base material are the same, and they are arranged overlappingly in the thickness direction.

[0021] Among them, before cutting and winding up the wide-width double-sided metal vapor deposition film roll material, it further includes the step of installing an insulating coating layer, a semiconductor coating layer or a conductive coating layer on one side of the wide-width double-sided metal vapor deposition film roll material by a vacuum vapor deposition, printing or coating process. Among them, the insulating coating layer includes a polymer material coating layer or a silicon dioxide vapor deposition layer, the semiconductor coating layer includes an aluminum oxide vacuum vapor deposition layer, and the conductive coating layer includes a carbon-based conductive ink coating layer, a printing layer or a graphene vapor deposition layer. Furthermore, the embodiment of the present invention provides a method for realizing saturation detection and distinction between urine and feces in a smart diaper, including the following steps. Steps of electrically connecting the first signal connection terminal and the second signal connection terminal of the capacitance detection device to the first detection electrode and the second detection electrode of the capacitive double-sided detection film of the smart diaper respectively, Steps of setting five thresholds, namely the first threshold, the second threshold, the third threshold, the fourth threshold and the fifth threshold, Steps of obtaining a second capacitance related to the excretion state of the smart diaper from the capacitive double-sided detection film by the capacitance detection device, Steps of comparing the change law of the second capacitance with the thresholds and judging the wet state of the smart diaper and the nature of the excrement based on the comparison result, Steps of judging that one excretion process has occurred when the increasing speed of the second capacitance exceeds the first threshold, Steps of judging that the excretion process has already ended when the second capacitance drops from the peak value, Steps of judging that the excrement is urine and the smart diaper is not yet saturated when the dropping speed of the second capacitance exceeds the second threshold, Steps of judging that the smart diaper is approaching saturation when the dropping speed of the second capacitance is lower than the third threshold, Steps of judging that the excrement is soft feces when the dropping speed of the second capacitance is lower than the fourth threshold or does not drop within a predetermined time, Steps of judging that the excrement is a mixture of urine and feces when the dropping speed of the second capacitance becomes fast and then slow and the speed difference exceeds the fifth threshold.

[0022] The beneficial effects of the present invention include the following: 1. The detection electrode is a metal electrode with a smooth and flat surface and good conductivity, which effectively reduces the internal resistance of the electrode and the capacitance between the electrode and the liquid, thereby lowering the time constant of the detection circuit and increasing the detection speed. 2. Since the metal electrode is formed by vacuum deposition, the thickness of the metal layer can be effectively reduced, providing the necessary flexibility. 3. The metal deposition layer is a completely integrated vacuum deposition layer, which is compatible with the normal vacuum deposition process and eliminates the need to create circuits with specific shape patterns using a perforation process, thus reducing costs. 4. Since the two metal deposition layers are arranged on both the upper and lower surfaces of the plastic film substrate, the width of the detection film can be effectively reduced, preventing capacitive interference caused by wetting on one side and contact with the human body on one side. 5. Since the metal deposition layer and the plastic film substrate are the same size and laminated together, they can be cut and used as needed. 6. The detection electrode and the plastic film substrate jointly constitute a parallel plate capacitor and generate a first capacitance, providing information about the area of ​​the detection film, determining the range and extent of the signal output, enabling damage compensation and adaptive operation. 7. Since there are no coating layers or holes on the metal vapor deposition layer that affect conductivity and connectivity, electrical connection to the detection device can be made at any position, increasing the versatility and convenience of the detection film. The capacitive double-sided sensing film of the embodiment of the present invention is particularly suitable for the production of smart disposable diapers, providing a simple, convenient, effective, and low-cost solution for detecting waste in disposable diapers, and creating favorable conditions for the smart upgrade of conventional disposable diapers.

[0023] To more clearly explain the technical methods of the embodiments of the present invention, the drawings that need to be used in the embodiments are briefly introduced below. However, the drawings described below represent only a few embodiments of the present invention, and it will be obvious to those skilled in the art that other drawings can be obtained based on these drawings without any creative work. [Brief explanation of the drawing]

[0024] [Figure 1] Figure 1 is a schematic diagram of the three-dimensional structure of a capacitive double-sided sensing film according to an embodiment of the present invention. [Figure 2] Figure 2 shows a schematic cross-sectional view of the A-A' section and an equivalent circuit diagram of the detection film of the embodiment of the present invention when it is in its initial / dry state. [Figure 3] Figure 3 shows a schematic cross-sectional view of the A-A' section and an equivalent circuit diagram when the detection film of an embodiment of the present invention is immersed in a liquid containing an electrolyte. [Figure 4] Figure 4 shows a simplified A-A' cross-sectional schematic and equivalent circuit diagram of the detection film of an embodiment of the present invention when it is immersed in a liquid containing an electrolyte. [Figure 5] Figure 5 is a schematic plan view of the detection film of an embodiment of the present invention when it has damage such as pinholes, cracks, or chips. [Figure 6] Figure 6 is a schematic diagram of the system structure that constitutes a smart diaper according to an embodiment of the present invention, in which the detection film of the present invention is installed inside a disposable absorbent product / diaper. [Figure 7] Figure 7 is a schematic diagram of the layered three-dimensional structure that constitutes the smart disposable diaper according to the embodiment of the present invention, in which the detection film according to the embodiment of the present invention is placed between the surface layer and the absorbent layer of the disposable diaper. [Figure 8] Figure 8 is a schematic diagram of the structure of a smart disposable diaper according to an embodiment of the present invention, which includes a slit used for capacitance signal output between the base film and the detection film. [Figure 9A] Figure 9A is a system configuration diagram showing the smart diaper according to an embodiment of the present invention when it is electrically connected to a capacitance detection device. [Figure 9B] Figure 9B is a system configuration diagram showing the smart diaper of the present invention when it is electrically connected to a capacitance detection device. [Figure 10] Figure 10 is a schematic diagram showing the presence of excrement inside the smart diaper according to an embodiment of the present invention. [Figure 11]Figure 11 is a schematic cross-sectional view of the B-B' section and an equivalent circuit diagram when highly fluid excrement (e.g., urine) is present in the smart diaper according to an embodiment of the present invention. [Figure 12] Figure 12 is a schematic cross-sectional view of the B-B' section when low-flowability excrement (e.g., loose stool) is present in the smart diaper according to an embodiment of the present invention. [Figure 13] Figure 13 is a schematic cross-sectional view C-C' when low-flowability excrement (e.g., loose stool) is present in the smart diaper according to an embodiment of the present invention. [Figure 14] Figure 14 is a schematic cross-sectional view of the detection film according to an embodiment of the present invention, in which a coating layer capable of changing the detection sensitivity is included on the first metal vapor deposition layer and the second metal vapor deposition layer. [Figure 15] Figure 15 is a system structure block diagram showing how the smart diaper, capacitance detection device, and wireless receiver according to an embodiment of the present invention together constitute a smart diaper status monitoring device. [Figure 16] Figure 16 is a flowchart of the method for creating a detection film in an embodiment of the present invention. [Figure 17] Figure 17 is a flowchart illustrating a method for achieving saturation detection and urine / feces differentiation in a smart disposable diaper according to an embodiment of the present invention. [Modes for carrying out the invention]

[0025] The following descriptions of each embodiment refer to the drawings and illustrate specific embodiments that can be used in carrying out the present invention. The directional and positional terms used in the present invention, such as “top,” “bottom,” “front,” “back,” “left,” “right,” “inside,” “outside,” “top,” “bottom,” and “side,” are merely references to the directions or positions in the drawings. In other words, the directional and positional terms used are for the purpose of explaining and understanding the present invention and do not limit the scope of protection of the present invention.

[0026] The present invention will be further described below in conjunction with the drawings. Referring to Figure 1, this is a schematic diagram of the three-dimensional structure of a capacitive double-sided detection film (abbreviated as capacitive detection film, double-sided detection film, or detection film) 10 of an embodiment of the present invention. The detection film 10 in the figure has a rectangular appearance, but in actual applications it may have various shapes. For clarity, each component of the detection film 10 in the figure is depicted as thick, but in actual applications these components are all very thin. The detection film of the embodiment of the present invention is a single-substrate film, and is not only thin but also flexible and can be cut and used according to the actual application needs.

[0027] The detection film 10 in the embodiment of the present invention includes a flexible, waterproof, insulating, and very thin plastic film substrate 13, and a first detection electrode 11 and a second detection electrode 12, respectively, installed on the upper and lower surfaces of the plastic film substrate 13. Theoretically, conductive materials, including metals, carbon black, graphene, and conductive inks, can all be used as detection electrodes. In the embodiment of the present invention, electrodes made of metal are referred to as metal electrodes, electrodes made of carbonaceous materials are referred to as carbon electrodes, and electrodes printed with conductive ink are referred to as printed electrodes.

[0028] Metal electrodes can be fabricated not only by methods such as metal foil or metal plating, but also by vacuum metal deposition. In other words, the metal electrode includes a metal deposition layer, and in such a case, the first detection electrode 11 and the second detection electrode 12 can be called not only the first metal electrode 11 and the second metal electrode 12, but also the first metal deposition layer 11 and the second metal deposition layer 12. Metal electrodes fabricated by metal foil or metal plating are usually relatively thick and hard and not very suitable for use on absorbent sanitary products. Therefore, in the embodiments of the present invention, the detection electrode is preferably composed of a metal deposition layer, and the first and second detection electrodes in the following embodiments are mainly described using the first and second metal deposition layers as examples.

[0029] The metal deposition layer can be produced by physical vapor deposition methods such as vacuum deposition and high-frequency sputtering. It is a single layer of metal deposited on both the upper and lower surfaces of a plastic film substrate, possessing not only excellent conductivity but also being extremely thin, with a metal deposition thickness typically between 20 and 200 nanometers, and exhibiting excellent flexibility.

[0030] Commonly used metal vapor deposition materials include aluminum, copper, gold, silver, zinc, and chromium, with aluminum being the most frequently used. Commonly used flexible plastic film substrates include polyester film (PET), polypropylene film (CPP, BOPP), polyethylene film (PE), and polyimide film (PI), with thicknesses generally between 1 and 100 micrometers. Preferably, a double-sided aluminum plated film produced by vapor deposition of 50 to 100 nanometers thick on a PET film substrate with a thickness of 3 to 12 micrometers offers excellent cost performance.

[0031] In Figure 1, the X-axis represents the length direction (vertical direction) of the detection film, the Y-axis represents the width direction (horizontal direction) of the detection film, and the Z-axis represents the thickness direction of the detection film. By convention, in embodiments of the present invention, the two surfaces in the thickness direction of the detection film are called the top and bottom surfaces, the two edges in the length direction are called both ends, the cross section in the length direction is called the longitudinal section, the two edges in the width direction of the detection film are called both sides, and the cross section in the width direction is called the transverse surface.

[0032] In the embodiment of the present invention, the first metal vapor deposition layer 11, the second metal vapor deposition layer 12, and the plastic film substrate 13 are perfectly identical in size and shape and are arranged in overlapping order along the thickness direction Z (i.e., their positive projections overlap each other). The metal vapor deposition layers 11 and 12, installed on both the upper and lower surfaces of the detection film, completely cover the plastic film substrate 13. They are smooth, flat, and integrated metal vapor deposition layers with no specific shaped patterns or margins on the deposition layer. This type of detection film is not only low-cost but also highly versatile. Furthermore, since there are no coatings, pores, or margins on the metal vapor deposition layer that affect conductivity, electrical connections to the connection terminals of the detection device can be made at any location, thus eliminating the need for any positioning process when using the detection film.

[0033] This type of detection film, completely coated with a metal vapor deposition layer, is the easiest to produce and can be generated simply by feeding a plastic film substrate into a conventional vacuum deposition machine and depositing the metal. In other words, it is compatible with conventional vacuum deposition processes and can create the required circuit patterns or margins without using any physical or chemical methods (e.g., partial deposition, laser watermarking, chemical etching / aluminum cleaning, etc.), effectively reducing the production cost of detection films.

[0034] In the embodiment of the present invention, the first metal vapor deposition layer 11, the second metal vapor deposition layer 12, and the plastic film substrate 13 jointly constitute a parallel plate capacitor, where the first and second metal vapor deposition layers 11 and 12 constitute the two electrodes of the parallel plate capacitor, and the plastic film substrate 13 constitutes the dielectric of the parallel plate capacitor. In the embodiment of the present invention, the capacitance generated thereby is referred to as the parallel plate capacitance, initial capacitance, or first capacitance. The magnitude of the first capacitance is directly proportional to the area of ​​the plastic film substrate, directly proportional to the dielectric constant of the plastic film substrate, and inversely proportional to the thickness of the plastic film substrate, and is independent of the shape and immersion state of the detection film. The A-A' cross-sectional view and equivalent circuit diagram of the detection film in a dry state are shown in Figure 2.

[0035] The initial capacitance / first capacitance C1 is unique to the detection film of the embodiment of the present invention. Once the area of ​​the detection film, the material and thickness of the plastic film substrate are determined, the first capacitance C1 is also determined accordingly and remains unchanged. Its capacitance is independent of the immersion state of the detection film. Due to the characteristics of the first capacitance of the embodiment of the present invention, in actual applications, the area of ​​the detection film can be estimated in reverse by detecting the first capacitance C1. This allows for the acquisition of standard parameters of the detection film, such as length information of the detection film obtained under known width conditions. Furthermore, standard information of the disposable diaper can be acquired from the length information, enabling adaptive operations such as automatic setting of the detection range and range of disposable diapers, and automatic setting of trigger thresholds for diaper change notifications / alert notifications for disposable diapers of different specifications.

[0036] The detection capability of the detection film in the embodiment of the present invention for liquids / excrement is achieved by the capacitance generated when the detection film is impregnated with an electrolyte-containing liquid / excrement (abbreviated as liquid). Among these capacitances, the electric double-layer capacitance is the most important and is also the main component of the second capacitance. According to the electric double-layer capacitance theory, when an electrolyte-containing liquid comes into contact with a conductive solid (detection electrode), an electric double-layer capacitance is generated at the contact interface between the solid and the liquid. When a DC voltage is applied between the electrodes, anions in the liquid gather on the positive electrode and cations in the liquid gather on the negative electrode. The anions and cations in the liquid and the alleles on the solid electrode form a single layer of ionic dielectric, thereby generating electric double-layer capacitance.

[0037] As shown in Figure 3, when the detection film 10 is immersed in an electrolyte-containing liquid 15 (tap water, physiological saline, urine / loose stool / sweat / menstrual blood, etc.), in addition to the initial capacitance / first capacitance C1 generated by the structure of the detection film itself between the first and second metal deposition layers 11 and 12, an electrical double layer capacitance C11 is generated between the first metal deposition layer 11 and the liquid 15, and an electrical double layer capacitance C12 is generated between the second metal deposition layer 12 and the liquid 15.

[0038] Since the electrolyte-containing liquid is conductive, and the potential 15' is equal everywhere in the conductive liquid, it is considered the ground level in the figure, and capacitances C11 and C12 are automatically connected in series. Therefore, the capacitance C2 generated by the liquid between the first metal deposition layer 11 and the second metal deposition layer 12 is the series value of capacitances C11 and C12, i.e., C2 = C11 × C12 / (C11 + C12), and in the embodiment of the present invention, the series value of capacitance C2 is called the second capacitance.

[0039] The second capacitance C2 is generated only when capacitances C11 and C12 are not simultaneously zero. Therefore, it is important to note that if either capacitance C11 or C12 is zero, the value after the two capacitances are connected in series will also be zero. In other words, capacitance C2 is generated only when at least a portion of the first metal deposition layer 11 and the second metal deposition layer 12 are simultaneously immersed in the liquid 15 and connected together.

[0040] The equivalent circuit diagram obtained by simplifying the circuit diagram shown in Figure 3 is shown in Figure 4. From Figure 4, it can be seen that the total capacitance C (abbreviated as capacitance C) generated between the first and second metal deposition layers 11 and 12 is the sum (parallel value) of the first capacitance C1 and the second capacitance C2. When capacitance C is detected, the value of the second capacitance C2 can be determined using the formula C2 = C - C1. Under immersion conditions, C2 is usually much larger than C1, so C1 can be ignored, and in this case, C2 can be considered to be approximately equal to C.

[0041] The magnitude of the second capacitance C2 is positively correlated with the area where the first metal vapor deposition layer 11 and the second metal vapor deposition layer 12 are immersed in liquid and connected, thereby providing a quantified liquid detection / wetness detection function. By placing the detection film 10 inside a disposable absorbent product, a function to detect the urine moisture / wetness state of the disposable absorbent product can be realized.

[0042] In the embodiments of the present invention, the main component of the second capacitance C2 is the electric double layer capacitance, also known as supercapacitance, and its capacitance is usually very large. The larger the capacitance, the larger the time constant τ (time constant formula τ=rc) of the detection circuit it constitutes, and the longer the time required for one capacitance detection. In practical applications, in order to increase the detection speed, it is usually necessary to make the capacitance value of the electric double layer capacitance between the two electrodes as small as possible.

[0043] The ability to generate electric double layer capacitance in a liquid varies depending on the conductive material. In the embodiments of the present invention, a metal vapor-deposited layer is preferably selected to constitute one of the detection electrodes because the metal vapor-deposited layer has a smooth surface, a dense structure, and excellent conductivity. This not only reduces the generation of electric double layer capacitance but also simultaneously lowers the internal resistance of the electrode, thereby effectively lowering the time constant of the detection circuit and increasing the speed of capacitance detection.

[0044] In the case of detection electrodes printed with carbon-based conductive ink, the surface is usually relatively rough, and the carbon-based material contains a large number of micropores. These micropores create a large specific surface area, which generates a large electrical double-layer capacitance. Furthermore, the electrical resistance of carbon electrodes is much greater than that of metal electrodes. Due to these factors, the time constant of the detection circuit formed by carbon electrodes is much larger than that of metal electrodes.

[0045] The detection film of the embodiment of the present invention can have various different shapes and designs, and its operational performance is not affected even if it is arbitrarily cut. Therefore, the detection film of the embodiment of the present invention has extremely good damage resistance. For example, although there is damage such as pinholes 103, cracks 104, and chips 105 on the detection film 10 in Figure 6, the detection film can still operate normally as long as these damages do not cut the detection film or significantly reduce the total effective area. At the same time, the total effective area of ​​the detection film of the embodiment of the present invention is measurable and is directly proportional to the initial capacitance / first capacitance C1. Therefore, damage can be evaluated by detecting the capacitance C1 before use, and appropriate adjustments / compensation (damage compensation) can be made during use. In this way, the detection error of the detection film caused by damage can be reduced.

[0046] The first capacitance C1 in the example of the present invention can also be used for adaptive operation. When a wetness detection system wants to know the degree of wetness (e.g., percentage of wetness), it is necessary to know the signal output range and range of the sensor in advance. In the case of wetness detection of disposable diapers, since disposable diapers come in various different model numbers, specifications, and sizes, size differences usually mean differences in absorbency, detection film area, signal output range, and range. If the size specification parameters can be known in advance by detecting the first capacitance, adaptive operation can be performed for disposable diapers with different specification parameters.

[0047] The detection film of the embodiment of the present invention has good flexibility and is particularly suitable for use in hygiene products / apparel, for example, for detecting urine moisture / wetness in disposable absorbent products / diapers. To facilitate the production of disposable diapers, the detection film of the embodiment of the present invention can be made in the form of a roll, with each roll of film reaching several thousand meters in length (preferably not less than 3,000 meters) and having a width ranging from a few millimeters to several centimeters (preferably 0.5 to 1.5 centimeters), specifically determined by demand.

[0048] This type of roll material, suitable for the production of disposable diapers, is created by cutting wide detection film, several meters wide and several thousand to over 10,000 meters long. It is then wound back onto a cylindrical core or placed on a reel to become narrow roll material. During the diaper production process, simply placing the detection film inside the diaper allows for the creation of smart diaper products with excrement quantity detection capabilities.

[0049] Figure 6 is a schematic diagram of the application of the detection film of an embodiment of the present invention in disposable absorbent products. Disposable absorbent products include absorbent hygiene products such as disposable diapers, disposable urine sheets, training pants, urine pads, and sanitary napkins. Disposable diapers are the most representative of these, so the following explanation mainly uses disposable diapers as an example, but the relevant explanations also apply to other disposable absorbent products. Disposable diapers typically consist of main components such as a surface layer (inner layer, dry layer, including hydrophilic nonwoven fabric), an absorbent layer (moisture-absorbing layer, including superabsorbent polymer SAP), and a base film (leak-proof layer, outer layer, including polyethylene film / PE film), which are laminated from top to bottom and bonded together as a single unit.

[0050] The wetness of a disposable diaper can be detected by a capacitance detection device (abbreviated as detection device or sensor) 30, which is usually a reusable external hardware device (which can be called smart hardware or a wearable device) that can be attached to the nonwoven fabric or front of the disposable diaper and can also detect excrement. The detection device 30 includes a first connection terminal 31 and a second connection terminal 32, which can be electrically connected to the first and second metal vapor deposition layers of the detection film, respectively, thereby enabling capacitance detection between the first and second metal vapor deposition layers, and allowing the wetness of the disposable diaper to be determined by the capacitance value. In the embodiment of the present invention, the detection film 10 together with the disposable diaper 20 constitutes a smart disposable diaper 28 (also called a smart absorbent product), and by adding the detection device 30, a system device is formed that can monitor the state of the smart disposable diaper.

[0051] Figure 7 is a schematic diagram of the three-dimensional structure of a smart diaper 28 according to an embodiment of the present invention. To make the relationships between each component easier to understand, the components are depicted separately in the figure, but in actual applications, these components are bonded together as a single unit. In the figure, 21 is the surface layer of the diaper, 22 is the absorbent layer of the diaper, and 25 is the base film of the diaper. In this embodiment, the detection film 10 is placed between the surface layer 21 and the absorbent layer 22, and focuses on monitoring the moisture state of the diaper surface layer. When using a diaper, its surface layer comes into direct contact with the skin of the human body, so the moisture state of the surface layer is consistent with the user's skin sensation.

[0052] In practical applications, the detection film 10 can be placed anywhere on any layer of the diaper. For example, it can be placed between the surface layer 21 and the absorbent layer 22, or on top of the surface layer 21 of the diaper 20, or between the absorbent layer 22 and the base film 25. The length of the detection film 10 is usually the same as the length of the diaper, but it may be slightly longer or shorter than the diaper if necessary.

[0053] Figure 8 is a schematic longitudinal cross-sectional view of a smart diaper according to an embodiment of the present invention, which includes a slit for capacitance signal output between the base film and the sensing film. The figure includes a surface layer 21, an absorbent layer 22, and a base film 25 of the disposable absorbent, with the sensing film positioned between the surface layer 21 and the absorbent layer 22, where the first metal vapor deposition layer 11 faces the surface layer 21 and the second metal vapor deposition layer 12 faces the absorbent layer 22.

[0054] In this embodiment, a slit 26 is included between the second metal vapor deposition layer 12 and the base film 25 so that a signal from the second metal vapor deposition layer 12 can be output. The second connection terminal 32 of the detection device 30 is inserted through this slit to make face-to-face contact and electrical connection with the second metal vapor deposition layer 12. The first connection terminal 31 of the detection device 30 penetrates the surface layer 21 made of nonwoven fabric and makes an electrical connection with the first metal vapor deposition layer 11 beneath the nonwoven fabric. This allows the device to output the second capacitance generated between the first and second metal vapor deposition layers 11 and 12 and transmit it into the detection device 30, thereby enabling capacitance detection and, based on the magnitude of the capacitance, enabling detection of the wet state of the smart diaper. Specifically, this is shown in Figure 9A.

[0055] A probe with a metal needle tip can be used at the connection terminal 31 of the detection device 30, and in this case, it can also be called the metal needle tip 31, which usually pierces the detection film when in use. To make the electrical connection between the metal needle tip 31 and the first metal vapor deposition layer 11 more reliable, a partially thickened conductive layer is installed at the corresponding position of the metal vapor deposition layer 11 by a method such as conductive ink printing, and by increasing the thickness of the conductive material in this part, the contact area in the thickness direction with the metal needle tip 31 is increased, improving the reliability of the connection, as shown in Figure 9B.

[0056] In Figure 9B, a partially thickened conductive layer 11A is included on the first metal vapor deposition layer 11. The metal needle tip 31 first penetrates the surface layer 21 of the disposable diaper, then penetrates the partially thickened conductive layer 11A, the first metal vapor deposition layer 11, the plastic film substrate 13, and the second metal vapor deposition layer 12 in that order, and finally pierces the elastic support (e.g., silica gel) 31A corresponding to the metal needle tip 31. Since the elastic support 31A is part of the capacitance detection device 30, it can provide elasticity for contact and electrical connection between the metal needle tip 31 and the first metal vapor deposition layer 11.

[0057] In the situation shown in Figure 9B, one might think that a short circuit occurs between the first metal deposition layer 11 and the second metal deposition layer 12 after the metal needle tip 31 penetrates the detection film. However, this is not true. The metal deposition layers in the embodiments of the present invention are very thin (usually less than 100 nm), and when the metal needle tip penetrates the detection film, a conical deformation occurs in the penetration portion of the detection film. As a result, effective contact does not occur between the metal needle tip 31 and the second metal deposition layer 12, thus avoiding the occurrence of a short circuit.

[0058] Even in the case of electrical connection between the metal needle tip 31 and the first metal deposition layer 11, poor contact may occur if the metal deposition layer 11 is too thin (contact resistance is too high or unstable). However, the partially thickened conductive layer 11A significantly increases the contact area with the metal needle tip 31 in the thickness direction of the detection electrode, making the electrical connection between the two more stable and reliable.

[0059] If you don't want to pierce too much, you can add a rigid contact surface to the upper surface of the elastic support 31A (for example, by attaching a single PCB to silica gel), which will prevent the metal needle tip 31 from penetrating into the elastic support 31A. If you don't want to pierce the detection film, you can reduce the sharpness of the metal needle tip 31 (by chamfering it), so that only the surface layer 21 penetrates and contacts the first metal vapor deposition layer 11, without penetrating the plastic film substrate 13 of the detection film.

[0060] In addition to including a slit 26 between the second metal vapor deposition layer 12 and the base film 25, if necessary, another slit can be included between the first metal vapor deposition layer 11 and the surface layer 21 to ensure face-to-face contact and electrical connection between the first connection end 31 and the first metal vapor deposition layer 11, thereby increasing the reliability of the connection. Conversely, if the presence of a slit is undesirable, or if electrical connection to the metal vapor deposition layer by inserting the connection end into a slit is undesirable, a hole / opening can be provided in the base film or surface layer at the edge of the diaper to expose the metal vapor deposition layer in that area, and face-to-face contact and electrical connection between the connection end of the detection device and the metal vapor deposition layer can be achieved at the opening.

[0061] Figure 10 shows the situation when a smart diaper, including an embodiment of the present invention, is immersed in a liquid containing human excrement / electrolytes. Inside the smart diaper 28 in the figure, there is a liquid 15 containing electrolytes, including human excrement such as urine, feces, sweat, and menstrual blood. Since the liquid contains electrolytes such as salt, it is conductive and can be considered a conductive liquid.

[0062] In the embodiment of the present invention, the detection film 10 is typically placed between the surface layer and the absorbent layer of a disposable diaper. Liquid enters from the surface layer of the disposable diaper, and then enters the absorbent layer by circulating around the detection film from both sides and being absorbed by the absorbent layer. In this situation, the width of the detection film 10 should not be too wide, as this affects the penetration of the liquid into the absorbent layer. Since the two detection electrodes in the embodiment of the present invention are arranged vertically in overlapping positions, the width can be reduced by more than half compared to the conventional technology in which the two detection electrodes are arranged horizontally in parallel and there is a gap / margin between the electrodes, thereby significantly reducing the influence of the detection film on liquid penetration.

[0063] Another advantage of arranging the two detection electrodes in the embodiment of the present invention in a vertically overlapping manner is that it prevents capacitive interference caused by only one side becoming wet or only one side of the human body contacting the detection film. In Figure 10, assuming that the liquid 15 is produced by sweating, the amount of sweating is limited, and normally both the upper and lower surfaces of the detection film 10 do not become wet or permeated. Therefore, under normal sweating conditions, a second capacitance is not generated, and capacitive interference due to sweating is avoided. Similarly, since the surface layer of the disposable diaper is in direct contact with the skin of the human body, if the two detection electrodes are arranged in parallel on the same surface of the detection surface, large capacitive interference will occur due to one-sided contact with the human body (for example, the buttocks pressing against the surface layer of the disposable diaper). However, this problem does not occur in the embodiment of the present invention, so it can be said that the detection film in the embodiment of the present invention has strong anti-interference capabilities.

[0064] When the liquid volume is relatively large (for example, during normal urination), both sides of the detection film 10 are simultaneously immersed in the liquid. That is, liquid is present on both the first metal vapor deposition layer 11 and the second metal vapor deposition layer 12, and the liquid on the first and second metal vapor deposition layers is connected to form an equipotential body. In this situation, capacitance C can be detected between the first and second metal vapor deposition layers 11 and 12, and capacitance C includes a first capacitance C1 generated by the structure of the detection film and a second capacitance C2 generated by liquid immersion.

[0065] Under wet / soaked conditions, the second capacitance C2 is much larger than the first capacitance C1. In this case, the first capacitance C1 can be ignored, and capacitance C can be directly considered as C2. Thus, the degree of dampness of a disposable diaper can be determined by detecting capacitance C.

[0066] The degree of immersion in a disposable diaper differs depending on the fluidity of the excrement. A schematic diagram of the vertical cross-section B-B' and the equivalent circuit when highly fluid excrement (e.g., urine 15) is present in the disposable diaper are shown in Figure 11. Because urine is highly fluid, it usually immerses both the first metal vapor deposition layer 11 and the second metal vapor deposition layer 12 of the detection film 10 simultaneously, and the degree of immersion in the upper and lower layers is similar.

[0067] Schematic diagrams of the B-B' longitudinal section and C-C' cross section when low-flowability excrement (e.g., loose stool 16) is present in the diaper are shown in Figures 12 and 13, respectively. Because the loose stool 16 has relatively poor flowability, a considerable portion accumulates on the surface layer 21 (as shown in 161), and then some of the liquid penetrates the surface layer (as shown in 162), while at the same time some of the liquid enters the absorbent layer 22 from around the detection film 10 (as shown in 163). The amount of liquid 165 that reaches the bottom surface of the second metal vapor deposition layer 13 of the detection film is usually less than the amount of liquid 162 on the top surface of the first metal vapor deposition layer 11. Such a situation reduces the ability of the detection film 10 to generate the second capacitance C2 or affects the detection film 10's ability to detect wetness on the diaper surface layer 21.

[0068] To solve the above problem, a coating layer capable of generating a larger capacitance (increased sensitivity) can be added on the second metal vapor deposition layer 12. This ensures that even if the amount of liquid 165 reaching the underside of the second metal vapor deposition layer 12 of the detection film is less than the amount of liquid 162 on the first metal vapor deposition layer 11, the capacitance generated between the second metal vapor deposition layer 12 and the liquid 165 will not fall below the capacitance generated between the first metal vapor deposition layer 11 and the liquid 162. In this way, a wetness detection function can be realized that does not affect wetness detection of the surface layer 21, or that focuses on the direction of the disposable diaper surface layer 21.

[0069] Another solution involves adding a coating layer on the first metal vapor deposition layer 11 that can reduce the generation of capacitance (lower sensitivity). This ensures that even if the amount of liquid 165 reaching the underside of the second metal vapor deposition layer 12 of the detection film is less than the amount of liquid 162 on the first metal vapor deposition layer 11, the capacitance generated between the second metal vapor deposition layer 12 and the liquid 165 will not be less than the capacitance generated between the first metal vapor deposition layer 11 and the liquid 162. In this way, a wetness detection function can be realized that does not affect wetness detection of the surface layer 21, or that focuses on the direction of the diaper surface layer 21.

[0070] In other words, the detection film of the embodiment of the present invention can achieve directional detection or targeted wet detection by changing the detection sensitivity of both the upper and lower surfaces. A schematic cross-sectional view of the capacitive double-sided detection film of the embodiment of the present invention, which includes a coating layer on the first metal vapor deposition layer 11 and the second metal vapor deposition layer 12 on which the detection sensitivity can be changed, is shown in Figure 14.

[0071] The difference from Figure 3 mentioned above is that the first metal vapor deposition layer 11 in Figure 14 includes an insulating coating layer (e.g., a polymer material coating layer, a silicon dioxide vapor deposition layer) or a semiconductor coating layer (e.g., a metal oxide vapor deposition layer containing aluminum oxide) 17, and in this case, the first metal vapor deposition layer 11 together with the coating layer 17 constitutes the first detection electrode 14 of the embodiment of the present invention.

[0072] The presence of the coating layer 17 prevents charged ions in the liquid / excrement 15 / 16 from directly contacting the first metal deposition layer 11. This reduces the generation of electrical double-layer capacitance between the first metal deposition layer 11 and the liquid 15, thereby lowering the detection sensitivity of the first detection electrode 14. In this situation, the capacitance C11 generated between the first metal deposition layer 11 and the liquid 15 is mainly electrolytic capacitance, in which the insulating coating layer or semiconductor coating layer 17 acts as a dielectric and the liquid in the excrement acts as an electrolyte. Its capacitance is directly proportional to the dielectric constant of the dielectric and inversely proportional to the thickness of the dielectric.

[0073] This embodiment includes a conductive coating layer 18 on the second metal vapor deposition layer 12, further composed of a material having a microporous structure or a relatively large specific surface area (e.g., carbon black or graphene), in which case the second metal vapor deposition layer 12 and the conductive coating layer 18 together constitute the second detection electrode 19 of this embodiment of the present invention. The presence of the conductive coating layer 18 significantly increases the contact surface area between the second detection electrode 19 and the charged ions in the liquid 15, thereby significantly increasing the ability to generate an electric double layer capacitance C12 between the second detection electrode 19 and the liquid 15, that is, significantly improving the detection sensitivity of the second detection electrode 19. The electrolytic capacitance C11 is connected in series with the electric double layer capacitance C12 to constitute the second capacitance C2 of this embodiment of the present invention.

[0074] In practical applications, insulating coating layers, semiconductor coating layers, or conductive coating layers can be placed on any layer / surface within the first and second metal vapor deposition layers. The insulating and semiconductor coating layers are used to reduce the detection sensitivity of the coated surface, thereby realizing an excrement detection function that emphasizes the direction of the coating layer. The conductive coating layer is used to increase the detection sensitivity of the coated surface, thereby realizing an excrement detection function that emphasizes directions other than the coating layer.

[0075] Figure 15 shows a block diagram of the system structure of the smart disposable diaper condition monitoring device according to an embodiment of the present invention, which is composed of the detection film 10, disposable absorbent material 20, detection device 30, and wireless receiver 50 according to an embodiment of the present invention. In the figure, the smart disposable diaper 28 includes the disposable absorbent material 20, and the detection film 10 is included inside the disposable absorbent material 20.

[0076] The detection device 30 includes a capacitance detection device 35 and a wireless transmitter 36. The detection device 30 is in contact with and electrically connected to the first detection electrode / first metal vapor deposition layer and the second detection electrode / second metal vapor deposition layer of the detection film 10 via a first connection terminal 31 and a second connection terminal 32. The capacitance detection device 35 acquires capacitance information between the first and second metal vapor deposition layers through the electrical connection, and after determining the wetness / excrement state of the smart diaper / disposable absorbent product based on the capacitance information and its change rules, the wireless transmitter 36 transmits the relevant state information wirelessly.

[0077] The wireless status information 38 is received by the wireless receiver 50, which includes a wireless receiving unit 51, a status display unit 52, and a status alarm unit 53. When the wireless receiving unit 51 receives the relevant status information, the status display unit 52 can display or indicate the status, or the status alarm unit 53 can issue an alarm. The wireless receiver 50 can include not only a dedicated wireless receiver and display device (e.g., an acoustic-optical alarm device) but also devices such as smartphones and personal computers. Apps and software can be run on mobile phones and personal computers, and the software and hardware combination method can realize the wet / excrement status detection, data recording, and inquiry functions based on capacitance detection of the embodiment of the present invention.

[0078] Since the detection film of the embodiment of the present invention can be cut and used as needed, not only is the versatility of the detection film increased, but the production / manufacturing efficiency of the detection film can also be greatly improved. For example, by first producing one lot of wide detection film roll material and then cutting it according to the various production needs of disposable diapers, detection film roll material having a specific width suitable for use with a particular disposable diaper can be obtained, which is the most cost-effective method of producing detection film.

[0079] The majority of the materials used in the production of disposable diapers are in the form of rolls. The base film, surface layer, and absorbent layer are first manufactured in roll form, and thousands of diapers can be produced from each roll, thus eliminating the need for frequent material supply and replacement. For detection film, it is desirable to manufacture it in roll form as well, in order to use it as a common material for disposable diaper production. The roll diameter / outer diameter of the detection film roll material should not be too large, as it may not be usable on some conventional disposable diaper production lines. A roll diameter not exceeding 45 centimeters and a length not less than 3000 meters is suitable, meaning that the detection film should not be too thick, and is usually controlled to be within 30 micrometers.

[0080] Figure 16 is a flowchart showing a method for creating a detection film according to an embodiment of the present invention, and includes the following steps.

[0081] Step S1601, wherein a polyester film, polyethylene film, polypropylene film, or polyimide film is used as the plastic film substrate, and the plastic film substrate is in the form of a wide roll material.

[0082] Step S1602 involves selecting one of the following metals as the metal material to be vapor-deposited: aluminum, copper, gold, silver, zinc, or chromium.

[0083] Step S1603 involves depositing a metal material onto one side of a plastic film substrate using vacuum deposition technology to create a first metal deposition layer, and then winding up the single-sided metal deposition film to form a wide single-sided metal deposition film roll.

[0084] Step S1604 involves using vacuum deposition technology to deposit a metal material onto the uncoated side of a single-sided metal-deposited film roll to form a second metal-deposited layer, creating a double-sided metal-deposited film, which is then wound up to form a wide double-sided metal-deposited film roll.

[0085] Step S1605: Installing an insulating coating layer, a semiconductor coating layer, or a conductive coating layer on one side of a wide double-sided metal vapor-deposited film roll material by vacuum deposition, printing, or coating process.

[0086] Step S1606: A wide double-sided metal vapor-deposited film roll is cut to the required width and wound up to create several narrow double-sided metal vapor-deposited film rolls, in which case both surfaces of the plastic film substrate are completely covered with a metal material, and the size and shape of the first metal vapor-deposited layer, the second metal vapor-deposited layer, and the plastic film substrate are the same and arranged in overlapping order in the thickness direction.

[0087] In the above steps, step S1605 can be omitted, and steps S1604 to S1606 can be jumped directly to obtain a narrow-width double-sided metal vapor-deposited film roll material without an insulating coating layer, semiconductor coating layer, or conductive coating layer.

[0088] In the steps described above, the insulating coating layer includes a polymer material coating layer or a silicon dioxide vapor deposition layer, the semiconductor coating layer includes an aluminum oxide vacuum deposition layer, and the conductive coating layer includes a carbon-based conductive ink coating layer / printing layer or a graphene vapor deposition layer.

[0089] Figure 17 is a flowchart of a method for realizing saturation detection and urine / feces differentiation in a smart disposable diaper according to an embodiment of the present invention, and includes the following steps.

[0090] Step S1701 involves electrically connecting the first signal connection terminal and the second signal connection terminal of the capacitance detection device to the first metal deposition layer and the second metal deposition layer of the capacitive double-sided detection film of the smart diaper, respectively.

[0091] Step S1702 involves setting five thresholds: the first threshold, the second threshold, the third threshold, the fourth threshold, and the fifth threshold.

[0092] Step S1703: Obtain a second capacitance related to the excrement state of the smart diaper from a capacitive double-sided detection film using a capacitance detection device.

[0093] Step S1704 involves comparing the second capacitance change law with the five preset thresholds mentioned above, and determining the wetness of the smart diaper and the properties of the excrement based on the comparison results.

[0094] Step S1705 determines that one discharge process has occurred if the second capacitance suddenly increases (exceeds the first threshold).

[0095] Step S1706, in which it is determined that the above discharge process has already been completed if the second capacitance has fallen from its peak value.

[0096] Step S1707: If the rate of fall of the second capacitance is fast (exceeds the second threshold), it is determined that the excrement is urine and the smart diaper is not yet saturated.

[0097] Step S1708 determines that the smart diaper is approaching saturation if the rate of decrease of the second capacitance is slow (below the third threshold).

[0098] Step S1709: If the rate of fall of the second capacitance is very slow (below the fourth threshold) or does not fall within a predetermined time, it is determined that the excrement is soft stool.

[0099] Step S1710: If the falling speed of the second capacitance increases and then decreases (the difference in speed exceeds the fifth threshold), it is determined that the excrement is a mixture of feces and urine.

[0100] The above disclosures are merely preferred embodiments of the present invention and, naturally, do not limit the scope of the present invention. Accordingly, equivalent modifications made based on the claims of the present invention shall continue to fall within the scope covered by the present invention.

Claims

1. A capacitive double-sided detection film for detecting excrement comprises a plastic film substrate and a first detection electrode and a second detection electrode, respectively, installed on the upper and lower surfaces of the plastic film substrate, wherein the first and second detection electrodes each include a first metal electrode and a second metal electrode for reducing the internal resistance of the electrode and the capacitance value between the electrode and the liquid, thereby reducing the time constant of the detection circuit, wherein the first and second metal electrodes each include a first metal deposition layer and a second metal deposition layer for reducing the thickness of the electrode by a metal deposition process to provide the necessary flexibility, wherein the metal deposition layer is a completely integrated vacuum deposition layer that completely covers both the upper and lower surfaces of the plastic film substrate, is compatible with a normal vacuum deposition process, and can reduce costs because it does not require the creation of a circuit with a specific shape pattern, wherein the first metal deposition layer and the second metal deposition layer are located on both the upper and lower surfaces of the plastic film substrate and are arranged in overlapping positions, and the capacitive double-sided detection film A capacitive double-sided detection film is used to reduce the width and prevent capacitive interference caused by wetting on one side and contact with the human body on one side, wherein the first metal vapor deposition layer, the second metal vapor deposition layer and the plastic film substrate are the same size and overlap each other so that they are easy to cut and use, and the size matching and the relationship of the overlapping layers do not change no matter how they are cut, and the first detection electrode, the second detection electrode and the plastic film substrate further constitute a parallel plate capacitor to provide information related to the area of ​​the capacitive double-sided detection film, perform adaptive operations by determining the range and range of the signal output, generate a first capacitance for performing damage compensation, and when excrement containing electrolytes infiltrates at least a portion of both the upper and lower surfaces of the capacitive double-sided detection film and connects together, a second capacitance positively correlated with the infiltration area is generated between the first detection electrode and the second detection electrode to provide information that the capacitive double-sided detection film is infiltrated by the excrement.

2. The magnitude of the first capacitance is directly proportional to the area and dielectric constant of the plastic film substrate, inversely proportional to the thickness of the plastic film substrate, and independent of the shape and immersion state of the capacitive double-sided sensing film, and, The second capacitance is the capacitance generated between the first detection electrode and the excrement, and is the series value of the capacitance generated between the second detection electrode and the excrement. Based on an analysis of the magnitude and change law of the series value, it is used to determine the excrement immersion state of the capacitive double-sided detection film and the properties of the excrement, and The metal vapor deposition layer does not contain any coating layers or pores that would affect its conductivity, and is characterized in that it can be electrically connected to a capacitance detection device at any position in order to enhance the versatility and convenience of the capacitive double-sided detection film. The capacitive double-sided detection film according to claim 1.

3. The invention includes a semiconductor coating layer or an insulating coating layer used to coat the outer surface of any of the aforementioned metal vapor-deposited layers and to reduce the capacitance value between the corresponding metal vapor-deposited layer and the excrement, thereby realizing a directional excrement detection function that emphasizes the direction of the coating layer, or A conductive coating layer having a microporous structure or a rough surface is used to coat the outer surface of any of the aforementioned metal vapor-deposited layers and increase the capacitance value between the corresponding metal vapor-deposited layer and the excrement, thereby realizing a directional excrement detection function that emphasizes the direction of the uncoated layer, or, The present invention is characterized by including a partially thickened conductive layer that covers a specific position on the outer surface of any of the aforementioned metal vapor-deposited layers, increases the thickness of the conductive material in that portion, and is used to provide further conductivity in the thickness direction when making an electrical connection with the aforementioned metal vapor-deposited layer at that portion using a metal needle-tip drilling method, thereby improving the reliability of the electrical connection. The capacitive double-sided detection film according to claim 1.

4. The capacitive double-sided detection film according to claim 3, characterized in that the semiconductor coating layer includes a metal oxide vapor deposition layer, the insulating coating layer includes an insulating material coating layer or vapor deposition layer, both of which are used to prevent charged ions in the excrement from directly contacting the outer surface of the metal vapor deposition layer and reducing the generation of the second capacitance, the conductive coating layer includes a carbon-based conductive ink coating layer or graphene vapor deposition layer to increase the generation of the second capacitance by increasing the surface area in contact with the excrement, and the partially thickened conductive layer includes a conductive ink coating layer or a printed layer.

5. The capacitive double-sided detection film according to any one of claims 1 to 4, characterized in that the metal vapor deposition layer includes a vacuum aluminum plating layer, the plastic film substrate includes a polyester film, polyethylene film, polypropylene film, or polyimide film, and the excrement includes urine, feces, sweat, or blood.

6. A smart diaper comprising a capacitive double-sided sensing film and a disposable absorbent material as described in claim 1, wherein the disposable absorbent material comprises a surface layer, an absorbent layer and a base film, which are layered and bonded in this order, and the capacitive double-sided sensing film is installed on the surface layer or between the surface layer and the base film, and the second capacitance provides information regarding the soaking state of the disposable absorbent material.

7. The area or length of the capacitive double-sided detection film corresponds to the model number specification or length of the disposable absorbent product, and the smart disposable diaper according to claim 6 is characterized in that it is used to facilitate adaptive operation by obtaining model number specification information or length information of the disposable absorbent product by detecting the first capacitance.

8. The capacitive double-sided detection film is installed between the surface layer and the base film, and a region without adhesive is included between the capacitive double-sided detection film and the surface layer or base film, thereby facilitating electrical connection between one or both sides of the capacitive double-sided detection film and the connection end of the capacitance detection device, and enabling the capacitance detection device to realize the excrement detection function of the disposable absorbent product, or The surface layer or base film includes an opening, exposing one or both sides of the capacitive double-sided detection film through the opening and allowing electrical connection to the connection terminal of the capacitance detection device, and enabling the detection of excrement from the disposable absorbent product through the capacitance detection device. The smart disposable diaper according to claim 6.

9. The capacitive double-sided detection film is placed between the surface layer and the absorbent layer, and the absorbent layer contains a polymer absorbent material, which gradually absorbs and traps moisture entering from the surface layer, thereby gradually drying the surface layer, causing the surface layer to undergo one change from wet to dry process with each urination process, and simultaneously causing the second capacitance to undergo a change from large to small, and, The rate at which the second capacitance changes from large to small is related to the degree of saturation of the absorption layer; the higher the degree of saturation, the slower the rate at which the second capacitance changes from large to small. Based on the rate at which the second capacitance changes from large to small, the degree of saturation of the absorption layer can be determined, and When the excrement is soft stool, the soft stool is not easily absorbed by the absorbent layer, so the second capacitance value is maintained at a high level for a long time, and based on this characteristic, it is possible to determine that the excrement is soft stool. The smart disposable diaper according to claim 8.

10. A smart diaper condition monitoring device comprising the smart diaper described in claim 6 and a capacitance detection device, wherein the capacitance detection device includes at least two connection terminals, which are electrically connected to the first detection electrode and the second detection electrode of the capacitive double-sided detection film, respectively, and which realize a waste condition monitoring function.

11. A smart diaper status monitoring device according to claim 10, characterized in that it includes a wireless transmitter and a wireless receiver for realizing wireless status monitoring and status display functions of the smart diaper by transmitting and receiving excrement status information of the smart diaper.

12. A step of using one of polyester film, polyethylene film, polypropylene film, or polyimide film as a plastic film substrate, wherein the plastic film substrate is in the form of a wide roll material, The steps include: using aluminum, copper, gold, silver, zinc, or chromium as the metal material to be deposited; The process involves depositing the metal material onto one side of the plastic film substrate using vacuum deposition technology to form a first metal deposition layer, creating a single-sided metal deposition film, and then winding it up to form a wide single-sided metal deposition film roll. The process involves using vacuum deposition technology to deposit the metal material onto the uncoated surface of the single-sided metal-deposited film roll material to form a second metal-deposited layer, creating a double-sided metal-deposited film, and then winding it up to form a wide double-sided metal-deposited film roll material. The method is characterized by comprising the steps of cutting the wide double-sided metal vapor-deposited film roll material to the required width and winding it up to produce several narrow double-sided metal vapor-deposited film roll materials, wherein both the upper and lower surfaces of the plastic film substrate are completely covered with the metal material, and the size and shape of the first metal vapor-deposited layer, the second metal vapor-deposited layer, and the plastic film substrate are the same and are arranged in overlapping positions in the thickness direction. A method for producing a capacitive double-sided detection film according to claim 1.

13. A method for producing a capacitive double-sided sensing film according to claim 12, further comprising the step of applying an insulating coating layer, a semiconductor coating layer, or a conductive coating layer to one side of the wide double-sided metal vapor-deposited film roll material by a vacuum deposition, printing, or coating process before cutting and winding the wide double-sided metal vapor-deposited film roll material.

14. The method for producing according to claim 13, characterized in that the insulating coating layer includes a polymer material coating or a silicon dioxide vapor deposition layer, the semiconductor coating layer includes an aluminum oxide vacuum deposition layer, and the conductive coating layer includes a carbon-based conductive ink coating layer, a printed layer, or a graphene vapor deposition layer.

15. The steps include electrically connecting the first signal connection terminal and the second signal connection terminal of the capacitance detection device to the first detection electrode and the second detection electrode of the capacitive double-sided detection film of the smart disposable diaper, respectively, The steps include setting five thresholds: the first threshold, the second threshold, the third threshold, the fourth threshold, and the fifth threshold. The steps include: obtaining a second capacitance related to the excrement state of the smart diaper from the capacitive double-sided detection film using the capacitance detection device; A step of comparing the second capacitance change law with the threshold and determining the wetness of the smart diaper and the properties of the excrement based on the comparison result, If the rate of increase of the second capacitance exceeds the first threshold, it is determined that one discharge process has occurred. The step of determining that the discharge process has already ended when the second capacitance falls below its peak value, If the falling speed of the second capacitance exceeds the second threshold, the step of determining that the excrement is urine and that the smart diaper is not yet saturated, The steps include determining that the smart diaper is approaching saturation if the rate of decrease of the second capacitance falls below the third threshold, If the falling speed of the second capacitance falls below the fourth threshold, or if it does not fall within a predetermined time, the step of determining that the excrement is soft stool, The method is characterized by including the step of determining that the excrement is a mixture of feces and urine if the rate of fall of the second capacitance increases and then decreases, and the difference in that rate exceeds the fifth threshold, A method for detecting saturation and distinguishing between urine and feces within a smart disposable diaper as described in claim 9.

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