Optical fiber mat

Abstract

The utility model relates to optical fiber technical field especially relates to a kind of optical fiber mat. Optical fiber mat includes monitoring mat main part, wherein monitoring mat main part includes optical fiber sensor, protective layer and net gauze layer, the both sides of optical fiber sensor are provided with protective layer, and the first side of optical fiber sensor is provided with net gauze layer between protective layer, optical fiber sensor is bent and set, and the intersection of optical fiber sensor is provided with ultraviolet glue piece, and ultraviolet glue piece is with optical fiber sensor and net gauze layer connection fixed. Since ultraviolet glue piece is located at the intersection of optical fiber sensor, ultraviolet glue piece can accurately fix optical fiber intersection, limit optical fiber shift and rub, eliminate low-frequency mutation noise from the source;It does not affect sensing performance: ultraviolet glue piece has high light transmittance, good flexibility after curing, neither blocks optical signal transmission, nor limits normal micro-bending of optical fiber sensor due to vital sign change, ensures monitoring sensitivity;Ultraviolet glue piece has good chemical stability, and does not fall off for long-term use.

Description

Technical Field

[0001] This utility model relates to the field of optical fiber technology, and in particular to an optical fiber pad. Background Technology

[0002] Fiber optic sensors monitor vital signs (such as heartbeat and respiration) based on the "fiber micro-bending effect." The principle is that changes in human vital signs (such as chest rise and fall, and vascular pulsation) compress the fiber optic sensor, causing it to bend slightly. This alters the transmission characteristics of the light signal, and vital sign data can be retrieved by detecting these changes. Due to their non-contact nature and lack of electromagnetic interference, these monitoring pads are widely used in home care and hospital monitoring.

[0003] To improve monitoring coverage and accuracy, fiber optic sensors are typically arranged within the monitoring pad. For example, in existing technologies, fiber optic sensors are embedded in a matrix within the mattress, densely arranged. However, this arrangement has a significant drawback: during use or transportation, the sensors are prone to loosening, displacement, or slight friction, causing abnormal fluctuations in their micro-bending state and generating low-frequency abrupt noise. This noise can mask true vital signs, leading to distorted monitoring data and even false alarms.

[0004] Therefore, there is an urgent need for an optical fiber pad to solve the above-mentioned technical problems. Utility Model Content

[0005] The purpose of this invention is to provide an optical fiber pad that can fix an optical fiber sensor and ensure that the optical fiber sensor produces normal micro-bending.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] This utility model provides an optical fiber pad, comprising:

[0008] The monitoring pad body includes a fiber optic sensor, a protective layer, and a mesh layer. Protective layers are provided on both sides of the fiber optic sensor. A mesh layer is provided between the first side of the fiber optic sensor and the protective layer. The fiber optic sensor is bent and has several intersections. Ultraviolet adhesive is provided at each intersection to connect and fix the fiber optic sensor to the mesh layer.

[0009] As an optional implementation of the fiber optic pad, the distance between adjacent intersections of the fiber optic sensor is h1, where 5cm≤h1≤10cm.

[0010] As an optional embodiment of the fiber optic pad, the diameter of the UV adhesive element is R, where 4mm ≤ R ≤ 5mm.

[0011] As an optional implementation of the fiber optic pad, the bending radius of the fiber optic sensor is r, where 2.5cm≤r≤5cm.

[0012] As an optional embodiment of the fiber optic pad, the fiber optic sensor is bent to form a vertical part, and the distance between adjacent vertical parts is h2, wherein 2.5cm≤h2≤5cm.

[0013] As an optional implementation of the fiber optic pad, the distance between adjacent intersections is set as h1, and the distance between the protective layers is set as h3, where h1:h3=1:(2~4).

[0014] As an alternative embodiment of the fiber optic pad, the fiber optic pad further includes a soft pad layer located at the bottom of the monitoring pad body.

[0015] As an alternative embodiment of the fiber optic pad, the fiber optic pad further includes a support layer located at the bottom of the monitoring pad body.

[0016] As an alternative embodiment of the fiber optic pad, the thickness of the support layer is d, where d ≥ 0.4 mm.

[0017] As an alternative embodiment of the fiber optic pad, the fiber optic pad further includes a packaging layer located at the top of the monitoring pad body and the bottom of the support layer.

[0018] As an alternative implementation of the fiber optic pad, the packaging layer includes an Oxford cloth layer.

[0019] The fiber optic pad provided by this utility model has at least the following beneficial effects:

[0020] The fiber optic pad includes a main body comprising a fiber optic sensor, a protective layer, and a mesh layer. Protective layers are located on both sides of the fiber optic sensor, and a mesh layer is positioned between the first side of the fiber optic sensor and the protective layer. The fiber optic sensor is bent, and a UV adhesive element is located at the intersection of the fiber optic sensors to connect and fix the fiber optic sensor to the mesh layer. The mesh layer makes deformation of the fiber optic sensor more noticeable, thereby improving the accuracy of signal detection. Because the UV adhesive element is located at the intersection of the fiber optic sensors, it can precisely fix the fiber optic intersection, limiting fiber displacement and friction, eliminating low-frequency abrupt noise at the source; it does not affect sensing performance; the UV adhesive element has high light transmittance and good flexibility after curing, neither obstructing light signal transmission nor restricting the normal micro-bending of the fiber optic due to changes in vital signs, ensuring monitoring sensitivity; the UV adhesive element has good chemical stability and will not detach over long-term use. Attached Figure Description

[0021] Figure 1This is an exploded view of the fiber optic pad provided in an embodiment of the present invention;

[0022] Figure 2 This is an exploded view of the main body of the monitoring pad provided in this embodiment of the utility model;

[0023] Figure 3 yes Figure 2 A schematic diagram of the status of the fiber optic sensor;

[0024] Figure 4 This is the original signal image monitored by the fiber optic pad after it has been cured with UV-curable adhesive;

[0025] Figure 5 yes Figure 4 Graph of the filtered low-frequency signal;

[0026] Figure 6 yes Figure 4 Graph of the filtered high-frequency signal;

[0027] Figure 7 This is the raw signal image monitored by the fiber optic pad without the use of UV-cured adhesive;

[0028] Figure 8 yes Figure 7 Graph of the filtered low-frequency signal;

[0029] Figure 9 yes Figure 7 A diagram of the filtered high-frequency signal.

[0030] In the picture:

[0031] 10. Monitoring pad body; 1. Protective layer; 2. Fiber optic sensor; 3. Mesh layer; 4. Soft pad layer; 5. Packaging layer; 6. Support layer. Detailed Implementation

[0032] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0033] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions. Moreover, "above," "on top of," and "over" the first feature in relation to the second feature includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0034] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0035] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0036] This embodiment provides an optical fiber pad that can fix the optical fiber sensor and prevent the cross-section of the optical fiber sensor from becoming loose and affecting the detection effect.

[0037] like Figures 1 to 3 As shown, the fiber optic pad includes a monitoring pad body 10, wherein the monitoring pad body 10 includes a fiber optic sensor 2, a protective layer 1, and a mesh layer 3. The protective layer 1 is provided on both sides of the fiber optic sensor 2, and the mesh layer 3 is provided between the first side of the fiber optic sensor 2 and the protective layer 1. The fiber optic sensor 2 is bent, and an ultraviolet adhesive is provided at the intersection of the fiber optic sensor 2 to connect and fix the fiber optic sensor 2 and the mesh layer 3.

[0038] The mesh design makes deformation of the fiber optic sensor 2 more noticeable, thereby improving the accuracy of signal detection. Since the UV adhesive is located at the intersection of the fiber optic sensors 2, it precisely fixes the fiber optic intersection, limiting fiber displacement and friction, thus eliminating low-frequency abrupt noise at the source. It does not affect sensing performance; the UV adhesive has high light transmittance and good flexibility after curing, neither obstructing light signal transmission nor restricting the normal micro-bending of the fiber optic due to changes in vital signs, ensuring monitoring sensitivity. The UV adhesive also has good chemical stability and will not detach over long-term use.

[0039] For example, protective layer 1 is made of transparent TPU, and its thickness is 0.7mm to 1.0mm, specifically 0.7mm, 0.8mm, 0.9mm, or 1mm. Protective layer 1 has high flatness and is used to isolate the fiber optic sensor 2 from other layers, preventing the fibers from snagging on the fiber optic sensor 2.

[0040] Specifically, ultraviolet (UV) adhesive is applied to all intersections of the fiber optic sensor 2, and after curing, it is fixed to the main body 10 of the monitoring pad. By applying UV adhesive to the intersections of the serpentine fiber optic sensor 2, loosening and displacement at the intersections can be effectively limited, avoiding low-frequency abrupt noise caused by abnormal micro-bending of the fiber optic sensor 2, and completely eliminating interference signals. Therefore, the fiber optic pad has high monitoring accuracy and can accurately detect changes in human vital signs. For example, in respiratory monitoring, the error can be controlled within 3 beats per minute; in heart rate monitoring, the error can also be controlled within 3 beats per minute.

[0041] UV adhesive cures quickly, requiring only 5 minutes of irradiation with an LED UV curing lamp for complete curing. Furthermore, the application process can be automated. For example, traditional methods might require manual application of adhesive to secure fiber optic sensors, while using UV adhesive and automated equipment allows for rapid application and curing at fiber optic sensor intersections, significantly improving production efficiency. Compared to traditional methods of securing fiber optic sensors, production efficiency can be increased by 3-5 times.

[0042] The main body 10 of the monitoring pad has a mesh layer 3, which ensures the user's comfort and meets the needs of daily lying down.

[0043] Specifically, the fiber optic sensor 2 is arranged in a serpentine pattern on the mesh layer 3, with several intersections formed by the serpentine arrangement. Each intersection is coated with UV adhesive, either by dot application or by applying it in a straight line along the intersection. After curing, the UV adhesive forms a UV adhesive element, which is fixed to the fiber optic sensor 2 and the mesh layer 3. This element restricts fiber displacement at the intersections and removes low-frequency abrupt noise. During dot application, the UV adhesive element completely covers the overlapping area of ​​the fibers without exceeding the intersection range, thus avoiding adhesive waste.

[0044] In some embodiments, the distance between adjacent intersections of the fiber optic sensor 2 is h1, where 5cm ≤ h1 ≤ 10cm. For example, the distance h1 between adjacent intersections of the fiber optic sensor 2 is 5cm, 6cm, 7cm, 8cm, 9cm, or 10cm, and is not specifically limited in this embodiment.

[0045] When the distance h1 between adjacent intersections of fiber optic sensors 2 is 5cm, more positions of the fiber optic sensors 2 can be securely fixed. When the distance h1 between adjacent intersections of fiber optic sensors 2 is 10cm, the amount of UV adhesive used can be reduced while still securing the light sensor. If the distance between adjacent intersections of fiber optic sensors 2 is too large, the density of the fiber optic sensors 2 will decrease. A distance h1 of 10cm between adjacent intersections of fiber optic sensors 2 ensures good detection performance.

[0046] The aforementioned spacing limits can balance the fixing effect of the fiber optic sensor 2 with the cost of UV adhesive material. If the distance h1 between adjacent intersections is too small, the amount of adhesive used will increase, and if it is too large, the fixing will be insufficient. Coating each intersection independently can ensure the fixing reliability of each intersection and avoid local noise caused by missed coating.

[0047] The fiber optic sensor 2 is a multimode silica fiber used to transmit optical signals and sense micro-bending changes. The fiber optic sensor 2 is arranged in a serpentine pattern with a bending radius of not less than 5mm, which can prevent excessive bending of the fiber from affecting optical transmission. The spacing between adjacent serpentine units is uniform.

[0048] The main body 10 of the monitoring pad is fixed by UV adhesive, and the protective layer 1 on the upper and lower layers of the fiber optic sensor 2 will be heat-sealed by a heat sealing machine.

[0049] The UV-curable adhesive features rapid curing, making it suitable for mass production. The cured adhesive possesses appropriate hardness while maintaining flexibility and strength, allowing it to withstand slight deformation of the monitoring pad without detaching. Furthermore, its light transmittance exceeds 90%, effectively blocking or absorbing optical signals transmitted through fiber optics, thus ensuring monitoring accuracy.

[0050] In some embodiments, the diameter of the UV-cured part is R, where 4mm ≤ R ≤ 5mm.

[0051] For example, the diameter R of the UV adhesive part can be 4mm, 4.1mm, 4.2mm, 4.3mm, 4.4mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm or 5mm, and is not specifically limited in this embodiment.

[0052] When the diameter of the UV adhesive component is 4mm, the fiber optic sensor 2 can be fixed while saving UV adhesive, avoiding the situation where the diameter of the UV adhesive component is too small to effectively fix the intersection of the fiber optic sensor 2. The bending diameter of the UV adhesive component is 5mm, which improves the fixing effect on the fiber optic sensor 2 and prevents the fiber optic sensor 2 from wobbling relative to other layers, thus avoiding impact on detection accuracy.

[0053] In some embodiments, the bending radius of the fiber optic sensor 2 is r, where 2.5cm≤r≤5cm.

[0054] For example, the value of r can be 2.5cm, 3cm, 3.5cm, 4cm, 4.5cm or 5cm. In this embodiment, no specific limitation is made. It can be understood that the bending diameter of the fiber optic sensor 2 is less than or equal to the distance between adjacent intersections of the fiber optic sensor 2, thereby fixing the fiber optic sensor 2 and reducing the amount of UV adhesive used.

[0055] In some embodiments, the fiber optic sensor 2 is bent to form a vertical part, and the distance between adjacent vertical parts is h2, wherein 2.5cm≤h2≤5cm.

[0056] For example, the distance h2 between adjacent vertical parts can be 2.5cm, 3cm, 4cm or 5cm, and is not specifically limited in this embodiment.

[0057] When the distance h2 between adjacent vertical parts is 2.5cm, it can ensure that the UV adhesive is applied at the bend of the fiber optic sensor 2. When the distance h2 between adjacent vertical parts is 5cm, the diameter of the UV adhesive can be increased, thereby increasing the bonding area between the fiber optic sensor 2 and the mesh layer 3.

[0058] By setting the spacing between adjacent vertical parts, the fixing effect and material cost can be balanced. If the distance h2 between adjacent vertical parts is too small, the amount of adhesive used will increase, and if it is too large, the fixing will be insufficient. Furthermore, the independent application of UV adhesive to each component can ensure the fixing reliability at each intersection and avoid local noise caused by missed coating.

[0059] In addition, the fiber optic sensor 2 is bent to form a horizontal part, and the distance between adjacent horizontal parts is h4, where 2.5cm≤h4≤5cm.

[0060] For example, the distance h4 between adjacent horizontal parts can be 2.5cm, 3cm, 4cm or 5cm, and is not specifically limited in this embodiment.

[0061] By setting the spacing between adjacent horizontal parts, the fixing effect and material cost can be balanced. If the distance h2 between adjacent horizontal parts is too small, the amount of adhesive used will increase, and if it is too large, the fixing will be insufficient. Furthermore, the independent application of UV adhesive to each component can ensure the fixing reliability at each intersection and avoid local noise caused by missed coating.

[0062] In some embodiments, the distance between adjacent intersections is set as h1, and the distance between protective layers 1 is set as h3, where h1:h3=1:(2~4).

[0063] For example, h1:h3=1:2, h1:h3=1:3, or h1:h3=1:4 are not specifically limited in this embodiment. Such a setting allows the fiber optic sensor 2 to have an intersection in the width direction of the protective layer 1, thereby ensuring the monitoring quality of the fiber optic sensor 2. Optionally, h1:h3=1:3 can reduce the number of fiber optic sensors 2 used while ensuring the monitoring quality of the fiber optic sensor 2.

[0064] like Figure 1 As shown, in some embodiments, the fiber optic pad also includes a cushioning layer 4 located at the bottom of the monitoring pad body 10. The cushioning layer 4 provides comfort to the person being monitored.

[0065] For example, the cushioning layer 4 is a foam layer, which can increase the resilience of the fiber optic sensor 2 and prevent it from being crushed. The cushioning layer 4 can be slow-rebound memory foam. For example, the thickness of the cushioning layer 4 is 1mm to 2mm, specifically, the thickness of the cushioning layer 4 is 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm or 2mm.

[0066] Optionally, the padding layer 4 is 1.5 mm thick, which can provide comfortable support while cushioning the excessive pressure of the human body on the optical fiber.

[0067] like Figure 1 As shown, in some embodiments, the fiber optic pad further includes a support layer 6, which is located at the bottom of the monitoring pad body 10. The support layer 6 improves the support effect on the monitoring pad body 10 above, preventing it from collapsing under downward pressure and affecting the monitoring effect. Thus, the support layer 6 reduces interference to the monitoring pad body 10 under external forces, improving monitoring accuracy. For example, the support layer 6 is a black PC board, and its thickness is 0.3mm to 0.5mm, specifically 0.3mm, 0.4mm, or 0.5mm. The support layer 6 ensures resilience.

[0068] like Figure 1As shown, in some embodiments, the fiber optic pad further includes a packaging layer 5, which is located on top of the monitoring pad body 10 and at the bottom of the support layer 6.

[0069] The packaging layer 5 is waterproof, preventing water ingress into the fiber optic sensor 2 and thus ensuring effective monitoring. For example, the packaging layer 5 includes an Oxford cloth layer.

[0070] For example, the protective layer 1 is made of transparent TPU with a thickness of 0.9mm, the cushioning layer 4 is made of plastic foam with a thickness of 1.5mm, and the support layer 6 is made of black PC board with a thickness of 0.4mm. During manufacturing, after obtaining the monitoring pad body 10, the cushioning layer 4 and the support layer 6 are placed directly under the monitoring pad body 10, and slightly fixed together with double-sided tape to form a whole. Finally, this part is wrapped with the packaging layer 5 and heat-sealed to obtain the fiber optic pad.

[0071] The UV adhesive is cured by UV lamp irradiation, and the cured UV adhesive does not react chemically with the fiber optic sensor 2, nor with the protective layer 1, the fiber optic sensor 2, and the mesh layer 3.

[0072] The fiber optic pad also includes a signal processing module, which is fixed to the end of the monitoring pad body 10 and electrically connected to both ends of the fiber optic sensor 2. The signal processing module is used to receive and process the signals detected by the fiber optic sensor 2 to output vital sign data.

[0073] The fiber optic pad provided by this utility model has a layered structure design for the main body 10 of the monitoring pad to balance comfort and fiber optic protection. The packaging layer 5 is located on the top and bottom layers of the fiber optic pad and is made of Oxford cloth to ensure waterproofing during use. The protective layer 1 is made of transparent TPU with high flatness and is used to isolate the fiber optic sensor from other layers to prevent the fibers from getting tangled with the fiber optic sensor 2. The soft pad layer 4 is made of slow-rebound memory foam, which provides comfortable support while buffering excessive pressure from the human body on the fiber optic sensor 2. The support layer 6 is made of black PC board to ensure rebound characteristics.

[0074] like Figures 4-6 As shown, Figure 4 The optical power signal obtained by the fiber optic pad provided in this embodiment fluctuates on the order of 0.1 dB. Figure 5 and Figure 6 Time-frequency analysis can be performed.

[0075] Figure 4 The low-frequency signal is separated from the signal after filtering (see Figure 5 The fluctuation amplitude of the low-frequency signal is on the order of approximately 0.1 dB, corresponding to the respiratory signal.

[0076] Figure 4 The high-frequency signal separated from the signal after filtering (participating) Figure 6 The high-frequency signal has a fluctuation amplitude of approximately 0.005 dB, which is used to calculate the heart rate signal.

[0077] like Figures 7-9 As shown, Figure 7 The image shows the optical power signal obtained by the existing fiber optic pad. It is easy to see from the image that... Figure 7 The interference signal in the time domain is large and the waveform cannot be observed in the time domain, making time domain analysis difficult.

[0078] Figure 8 yes Figure 7 After filtering, the low-frequency signal is separated out. The fluctuation amplitude of this low-frequency signal is on the order of approximately 0.1 dB, corresponding to the respiratory signal. Interference signals have little impact on this part.

[0079] Figure 9 yes Figure 7 The high-frequency signal is separated after the signal is filtered. Because... Figure 8 Interference from low and medium frequency signals Figure 9 The high-frequency signal is significantly affected, impacting the accuracy of heart rate calculation.

[0080] As can be seen from the above analysis, the interference level of the signal obtained by the fiber optic pad monitoring provided in this embodiment is greatly reduced, and the results are more accurate.

[0081] Of course, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. An optical fiber pad, characterized in that, include: The main body (10) of the monitoring pad includes an optical fiber sensor (2), a protective layer (1) and a mesh layer (3). The optical fiber sensor (2) is provided with a protective layer (1) on both sides. A mesh layer (3) is provided between the first side of the optical fiber sensor (2) and the protective layer (1). The optical fiber sensor (2) is bent and has several intersections. Ultraviolet adhesive is provided at the intersections to connect and fix the optical fiber sensor (2) to the mesh layer (3).

2. The fiber optic pad according to claim 1, characterized in that, The distance between adjacent intersections of the fiber optic sensor (2) is h1, where 5cm≤h1≤10cm.

3. The fiber optic pad according to claim 1, characterized in that, The diameter of the UV-cured adhesive part is R, where 4mm ≤ R ≤ 5mm.

4. The optical fiber pad according to any one of claims 1-3, characterized in that, The bending radius of the fiber optic sensor (2) is r, where 2.5cm≤r≤5cm.

5. The fiber optic pad according to any one of claims 1-3, characterized in that, The fiber optic sensor (2) is bent to form a vertical part, and the distance between adjacent vertical parts is h2, wherein 2.5cm≤h2≤5cm.

6. The fiber optic pad according to any one of claims 1-3, characterized in that, The distance between adjacent intersections is set as h1, and the distance between the protective layers (1) is set as h3, where h1:h3=1:(2~4).

7. The fiber optic pad according to any one of claims 1-3, characterized in that, The fiber optic pad also includes a cushion layer (4), which is located at the bottom of the monitoring pad body (10).

8. The optical fiber pad according to any one of claims 1-3, characterized in that, The fiber optic pad also includes a support layer (6), which is located at the bottom of the monitoring pad body (10).

9. The optical fiber pad according to claim 8, characterized in that, The fiber optic pad also includes a packaging layer (5), which is located at the top of the monitoring pad body (10) and the bottom of the support layer (6).

10. The optical fiber pad according to claim 9, characterized in that, The packaging layer (5) includes an Oxford cloth layer.

Images