A flexible pressure sensor for vehicle seats and its preparation method

Abstract

The present invention discloses a flexible pressure sensor for an automotive seat and a preparation method thereof, belonging to the technical field of flexible sensors. It includes a base layer, an electrode layer disposed on the base layer, an insulating layer covering the surface of the electrode layer, and the sensing area of the electrode layer is correspondingly exposed; a first encapsulation layer, in which a plurality of sensitive layers are arranged, and the sensitive layer and the sensing area of the electrode layer convert the pressure signal into an electrical signal through the piezoresistive effect; a pressing layer, the pressing layer is made of a flexible material, and a hard gasket is embedded in the pressing layer, and the hard gasket, the sensitive layer and the sensing area of the electrode layer are aligned in the thickness direction of the sensor. In this application, a plurality of second through holes are opened in the pressing layer, and hard gaskets are embedded in the second through holes. Through the cooperation of the flexible pressing layer and the hard gaskets, the whole sensor has flexibility, is convenient to bend, does not affect the driving experience of the driver, and the hard gaskets can be used as force-bearing carriers, which will not deform due to force, ensuring accurate monitoring of pressure.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible sensors, and particularly relates to a flexible pressure sensor for automotive seats and a preparation method thereof. Background Art

[0002] In recent years, with the continuous development of new energy technologies, the number of automobiles has been increasing rapidly. Among the components of an automobile, the automotive seat is a key component that affects the driving experience of the driver and monitors the state. By monitoring the pressure distribution on the automotive seat, it is helpful to accurately grasp the driving habits of the driver, provide support for adjusting the state of the automotive seat, and enhance the driving experience. At the same time, the monitoring of the pressure state of the automotive seat during driving can also accurately judge the driving state of the driver, and can provide intervention or reminder in dangerous situations such as fatigue driving, aggressive driving, or distracted driving of the driver, so as to reduce the occurrence of traffic accidents and ensure the life and property safety of the driver.

[0003] The interior of an automotive seat is mainly filled with flexible sponge materials. The arrangement of conventional rigid pressure sensors inside the automotive seat will cause a decline in the riding experience of the driver. Although the structure of conventional flexible sensors will not affect the riding experience of the driver, when a person sits on it, the flexible pressure sensor often compresses and deforms together with the sponge material, resulting in inaccurate pressure detection of the pressure sensor, poor pressure detection effect, and inability to accurately detect the pressure distribution of the automotive seat. Summary of the Invention

[0004] In view of one or more of the above-mentioned defects or improvement requirements of the prior art, the present invention provides a flexible pressure sensor for automotive seats to solve the problem that the existing flexible pressure sensors cannot accurately detect the pressure distribution of automotive seats.

[0005] To achieve the above object, the present invention provides a flexible pressure sensor for automotive seats, which includes:

[0006] A base layer, an electrode layer provided on the base layer, and an insulating layer covering the surface of the electrode layer;

[0007] A plurality of first through holes are formed in the insulating layer, and the sensing area of the electrode layer corresponds to each of the first through holes;

[0008] A first encapsulation layer, the first encapsulation layer, the insulating layer and the base layer form a pressing gap, a plurality of sensitive layers are arranged in the first encapsulation layer, the sensitive layers are arranged in the pressing gap, and the sensitive layers and the sensing area of the electrode layer convert the pressure signal into an electrical signal through the piezoresistive effect;

[0009] A pressing layer, wherein the pressing layer is arranged on the side of the first packaging layer away from the insulating layer, the pressing layer is made of flexible material, and a plurality of second through holes are opened on the pressing layer, the plurality of second through holes are arranged in one-to-one correspondence with the plurality of first through holes, and a hard gasket is embedded in each of the second through holes, and the sensing areas of the hard gasket, the sensitive layer and the electrode layer are aligned in the thickness direction of the sensor.

[0010] As a further improvement of the present invention, a first adhesive layer is further provided between the first encapsulation layer and the insulating layer, a plurality of third through holes are opened on the first adhesive layer, and the sensitive layer is provided in the third through holes;

[0011] The first adhesive layer is provided with at least one first air channel in a circumferential direction along the sensitive layer, and the first air channel connects the pressing gap with the outside.

[0012] As a further improvement of the present invention, the first air channel includes a first sub-air channel and a second sub-air channel which are arranged in sequence and continuously in a direction away from the sensitive layer;

[0013] The first sub-airway connects the pressing gap and the second sub-airway, and the width of the first sub-airway is 1-2 mm;

[0014] The second sub-air channel connects the first sub-air channel with the outside, and the width of the second sub-air channel is 0.01-0.2 mm.

[0015] As a further improvement of the present invention, a second air channel is connected between each of the third through holes, and each of the first air channels connects the second air channel with the outside.

[0016] As a further improvement of the present invention, a fourth through hole is opened in the first adhesive layer, and the fourth through hole forms an embedded area in the first adhesive layer. Each of the sensitive layers is respectively attached to the embedded area, and the embedded area is connected to the outside through the first air channel.

[0017] As a further improvement of the present invention, it further comprises a second encapsulation layer, wherein the second encapsulation layer is arranged on a side of the pressing layer away from the first encapsulation layer;

[0018] A second adhesive layer is provided between the pressing layer and the first packaging layer, and a third adhesive layer is provided between the pressing layer and the second packaging layer.

[0019] As a further improvement of the present invention, the base layer, the first encapsulation layer and the second encapsulation layer are PET films or PI films;

[0020] The first adhesive layer, the second adhesive layer and the third adhesive layer are OCA optical adhesives;

[0021] The electrode layer is made of silver paste material, the insulating layer is made of ink material, and the sensitive layer is made of carbon paste material;

[0022] The hard gasket is made of iron sheet, copper sheet, aluminum sheet or acrylic sheet.

[0023] As a further improvement of the present invention, the thickness of the base layer, the first encapsulation layer and the second encapsulation layer is 0.1-0.2 mm;

[0024] The thickness of the insulating layer is 10-15 μm, the thickness of the first adhesive layer, the second adhesive layer and the third adhesive layer are all 0.08-0.12 mm, the thickness of the pressing layer is 0.2-0.3 mm, the thickness of the electrode layer is 6-10 μm, and the thickness of the sensitive layer is 6-10 μm.

[0025] The present application also includes a method for preparing a flexible pressure sensor for a car seat, which comprises the following steps:

[0026] S1, selecting a flexible film of set thickness as the base layer, the first packaging layer, the pressing layer and the second packaging layer;

[0027] S2, screen printing silver paste wire on the surface of the substrate layer to prepare a formed electrode layer;

[0028] S3, printing insulating paste on the surface of the electrode layer to cover the silver paste wire to form an insulating layer, and partially exposing the silver paste wire to reserve a sensing area;

[0029] S4, screen-printing carbon-based slurry on the surface of the first packaging layer to form a sensitive layer, and cutting the OCA glue into a set shape and attaching it to the surface of the first packaging layer so that the sensitive layer is exposed;

[0030] S5, cutting the OCA adhesive layer into a hole of a set size by laser cutting;

[0031] S6, attaching the first packaging layer to the base layer so that the sensitive layer is arranged toward the sensing area of ​​the electrode layer;

[0032] S7, cutting a circular hole structure on the pressing layer, attaching the pressing layer to the side of the first packaging layer away from the insulating layer, and attaching a hard gasket to the circular hole area of ​​the pressing layer;

[0033] S8, connecting the interface of the electrode layer to the interface of the back-end signal processing circuit, and attaching the second packaging layer to the side of the pressing layer away from the first packaging layer.

[0034] The present application also includes a method for preparing a flexible pressure sensor for a car seat, which comprises the following steps:

[0035] S1, selecting a flexible film of set thickness as the base layer, the first packaging layer, the pressing layer and the second packaging layer;

[0036] S2, screen printing silver paste wire on the surface of the substrate layer to prepare a formed electrode layer;

[0037] S3, printing insulating paste on the surface of the electrode layer to cover the silver paste wire to form an insulating layer, and partially exposing the silver paste wire to reserve a sensing area;

[0038] S4, screen printing a carbon-based slurry on the surface of the first encapsulation layer to form a sensitive layer;

[0039] S5. Cutting a hole of a set size on the surface of the OCA adhesive layer by laser cutting, attaching the OCA adhesive layer to the surface of the first packaging layer, and exposing the sensitive layer;

[0040] S6, attaching the first packaging layer to the base layer so that the sensitive layer is arranged toward the sensing area of ​​the electrode layer;

[0041] S7, cutting a circular hole structure on the pressing layer, attaching the pressing layer to the side of the first packaging layer away from the insulating layer, and attaching a hard gasket to the circular hole area of ​​the pressing layer;

[0042] S8, connecting the interface of the electrode layer to the interface of the back-end signal processing circuit, and attaching the second packaging layer to the side of the pressing layer away from the first packaging layer.

[0043] The above-mentioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0044] In general, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:

[0045] (1)The flexible pressure sensor for vehicle seats of the present invention forms an electrode layer on a base layer, and then covers most of the circuits of the electrode layer through an insulating layer, leaving only a partial sensing area through a first through-hole. Then, a sensitive layer is provided on a first encapsulation layer, and a pressing gap between the sensing area and the sensitive layer is formed through the first through-hole. When an external force acts on the sensor, the sensitive layer moves towards the sensing area. When they come into contact, the resistance value of the electrode layer changes correspondingly and reflects the pressure change in the form of an electrical signal to achieve pressure sensing. At the same time, in the present application, a pressing layer is provided on the back surface of the first encapsulation layer. The pressing layer is also made of a flexible material, and a second through-hole is provided on the pressing layer, and a hard gasket is embedded at the second through-hole. Through the cooperation form of the pressing layer and the hard gasket, the whole sensor has flexibility, is convenient to bend, and does not affect the riding experience of the driver. Secondly, the hard gasket, the sensing area of the sensitive layer and the electrode layer are correspondingly arranged. When the sensor is stressed, the hard gasket serves as the force-bearing carrier for the sensing areas of the sensitive layer and the electrode layer, and it will not deform due to stress, enabling the accurate pressure perception of the sensor to be reflected. Moreover, the hard gasket can restrict the sensor structure in the area where it is located, avoiding problems such as wrinkles in the sensing area and the sensitive layer, so as to ensure the accurate monitoring of pressure by the flexible pressure sensor for vehicle seats.

[0046] (2)The flexible pressure sensor for vehicle seats of the present invention opens a first air passage in a first adhesive layer, and uses the first air passage to connect the external space with the pressing gap, so that the air pressure inside and outside the sensor is balanced, ensuring the accurate perception of the pressure of the pressure sensor.

[0047] (3)For the flexible pressure sensor for vehicle seats of the present invention, since the sensing area of the electrode layer and the sensitive layer in the present application are both arranged in the pressing gap, using a conventional connection method will cause external dust or powder to enter the pressing gap through the air passage, affecting the accurate monitoring of pressure. Based on this, the first air passage in the present application is set as a stepped air passage structure of a first sub-air passage and a second sub-air passage. The first sub-air passage is used for the normal flow of air, and the second sub-air passage is at the end of the first sub-air passage. By reducing the size of the second sub-air passage, it is difficult for external dust or powder to enter the interior of the sensor, ensuring the stable operation of the sensor.

[0048] (4)The flexible pressure sensor for vehicle seats of the present invention can, by adopting the cooperation form of a first air passage and a second air passage, make the first air passage away from the area where the sensitive layer is located, which can not only connect the pressing gap of the sensor with the outside, but also make the sensitive layer away from the opening area where the sensor is connected to the outside, minimizing the probability of external dust and the like contacting the sensitive layer as much as possible, ensuring the accuracy of pressure monitoring.

[0049] (5)The preparation method of the flexible pressure sensor for vehicle seats according to the present invention covers the electrode layer with an insulating layer, leaving only the sensing area of the electrode layer exposed to ensure the normal operation of the internal pressure sensing circuit of the sensor. Then, a sensitive layer is set corresponding to the sensing area, and a pressing gap is reserved between the insulating layer and the sensing area. When the sensitive layer is stressed, it will move towards the sensing area, and the contact area between the sensitive layer and the sensing area reflects the magnitude of the pressure, thereby realizing the perception of pressure. At the same time, in this application, a set-size hole is formed on the first adhesive layer by laser cutting, so that the pressing gap communicates with the outside, avoiding the expansion or contraction of the pressing gap in hot and cold environments, ensuring the accurate perception of pressure by the sensitive layer and the sensing area. Moreover, in this application, a structure with a hard gasket embedded in the pressing layer is adopted. The pressing layer itself has the characteristics of flexibility and foldability, avoiding the influence of the sensor on the driving experience of the driver. The hard gasket structure is arranged corresponding to the sensitive layer and the sensing area, so that the external pressure is accurately transmitted to the sensitive layer, ensuring the accurate perception of pressure by the pressure sensor. Description of the Drawings

[0050] Figure 1 is the overall structural schematic diagram of the flexible pressure sensor for vehicle seats in the embodiment of the present invention;

[0051] Figure 2 is the cross-sectional structural schematic diagram of the flexible pressure sensor for vehicle seats in the embodiment of the present invention;

[0052] Figure 3 is the structural schematic diagram of the first adhesive layer in one embodiment of the present invention;

[0053] Figure 4 is the structural schematic diagram at the first hole in the embodiment of the present invention;

[0054] Figure 5 is the structural schematic diagram of the first adhesive layer in one embodiment of the present invention;

[0055] Figure 6 is the structural schematic diagram of the first adhesive layer in one embodiment of the present invention.

[0056] In all the drawings, the same reference numerals represent the same technical features, specifically:

[0057] 1, base layer; 2, electrode layer; 3, insulating layer; 4, sensing area; 5, sensitive layer; 6, first adhesive layer; 7, first encapsulation layer; 8, hard gasket; 9, pressing layer; 10, second encapsulation layer; 11, first hole; 12, second hole; 13, fourth through hole; 14, second adhesive layer; 15, third adhesive layer;

[0058] 111, first sub-air duct; 112, second sub-air duct. Detailed Embodiments

[0059] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0060] In the description of the present invention, it should be understood that unless otherwise specified, the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0061] In addition, unless otherwise specified, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0062] In the present invention, unless otherwise clearly defined and limited, terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0064] Example:

[0065] See also Figures 1 - 6 The flexible pressure sensor for a car seat in a preferred embodiment of the present invention comprises a base layer 1, an electrode layer 2 arranged on the base layer 1, the surface of the electrode layer 2 is covered with an insulating layer 3, and a plurality of first through holes are provided on the insulating layer 3, and the sensing area 4 of the electrode layer 2 is arranged corresponding to each first through hole; and a first packaging layer 7, a pressing gap is formed between the first packaging layer 7, the insulating layer 3 and the base layer 1, and a plurality of sensitive layers 5 are arranged in the first packaging layer 7, and the sensitive layers 5 are arranged in the pressing gap, and the sensitive layers 5 and the sensing area 4 of the electrode layer 2 convert the pressure signal into an electrical signal through the piezoresistance effect; a pressing layer 9, which is arranged on the side of the first packaging layer 7 away from the insulating layer 3, and the pressing layer 9 is a flexible material, and a plurality of second through holes are provided on the pressing layer 9, and the plurality of second through holes are arranged one by one with the plurality of first through holes, and a hard gasket 8 is arranged at the second through hole, and the hard gasket 8, the sensitive layer 5 and the sensing area 4 of the electrode layer 2 are aligned in the thickness direction of the sensor.

[0066] Specifically, in this application, an electrode layer 2 is formed on the base layer 1, and then most of the circuits of the electrode layer 2 are covered by the insulating layer 3. Only a part of the sensing area 4 is reserved through the first through hole. Then, a sensitive layer 5 is arranged on the first encapsulation layer 7, and a pressing gap between the sensing area 4 and the sensitive layer 5 is formed through the first through hole. When an external force acts on the sensor, the sensitive layer 5 moves towards the sensing area 4. When they come into contact, the resistance value of the electrode layer 2 changes correspondingly and reflects the pressure change in the form of an electrical signal, realizing pressure sensing. At the same time, in this application, a pressing layer 9 is arranged on the back of the first encapsulation layer 7. The pressing layer 9 is also made of a flexible material, and a second through hole is arranged on the pressing layer 9, and a hard gasket 8 is embedded at the second through hole. Through the cooperation form of the pressing layer 9 and the hard gasket 8, the whole sensor has flexibility, is convenient to bend, and does not affect the driving experience of the driver. Secondly, the hard gasket 8, the sensitive layer 5 and the sensing area 4 of the electrode layer 2 are arranged correspondingly. When the sensor is stressed, the hard gasket 8 serves as the force-bearing carrier for the sensitive layer 5 and the sensing area 4 of the electrode layer 2, and it will not deform due to the force, so that the pressure perception of the sensor is accurately reflected to ensure the accurate monitoring of the pressure by the flexible pressure sensor for automotive seats.

[0067] Specifically, the first encapsulation layer 7, the insulating layer 3 and the base layer 1 in this application form a pressing gap, which means that after the three are stacked, the first encapsulation layer 7 and the base layer 1 close both ends of the first through hole on the insulating layer 3 on both sides to form a pressing gap.

[0068] As an optional embodiment of the present invention, a first adhesive layer 6 is further provided between the first encapsulation layer 7 and the insulating layer 3 of this application. A plurality of third through holes are correspondingly opened on the first adhesive layer 6. Each sensitive layer 5 is arranged in the third adhesive layer 15, and at least one first air passage is opened in the circumferential direction of the first adhesive layer 6 along the sensitive layer 5. The first air passage communicates the pressing gap with the outside. The third through hole is mainly used to form an avoidance space on the first adhesive layer 6 to ensure that the contact between the sensitive layer 5 and the sensing area 4 of the electrode layer 2 is not affected. Secondly, the pressure sensor in this application is mainly used for automotive seats and is enclosed inside the vehicle body. Due to the uncertainty of the automotive use environment, when the external temperature is relatively high, the internal temperature of the vehicle is also relatively high. After the flexible pressure sensor is heated, the internal space of its pressing gap expands due to heat, resulting in the overall deformation and bulging of the flexible pressure sensor, causing inaccurate pressure sensing and monitoring. Based on this, the first adhesive layer 6 is correspondingly arranged in this application. The first adhesive layer 6 can bond the first encapsulation layer 7 and the insulating layer 3 into one body, and the first air passage on the first adhesive layer 6 can communicate the external space with the pressing gap, so that the internal and external air pressures are balanced, ensuring the accurate perception of the pressure of the pressure sensor.

[0069] Preferably, the setting direction and setting quantity of the first air channel are not limited here, and the first air channel only needs to connect the pressing gap with the outside. As an optional embodiment of the present invention, the first air channel in the present application can be directly connected to the third through hole, and the size of the sensitive layer 5 is smaller than the aperture of the third through hole, so that the first air channel is connected to the pressing gap.

[0070] As an optional embodiment of the present invention, the first air channel in the present application is arranged in sequence along the direction away from the sensitive layer 5, and the first sub-air channel 111 and the second sub-air channel 112 are arranged in sequence; wherein, the first sub-air channel 111 connects the pressing gap with the second sub-air channel 112, and the width of the first sub-air channel 111 is 1-2 mm; the second sub-air channel 112 connects the first sub-air channel 111 with the outside, and the width of the second sub-air channel 112 is 0.01-0.2 mm. Since the sensing area 4 and the sensitive layer 5 of the electrode layer 2 in the present application are both arranged in the pressing gap, the conventional connection method will cause external dust or powder to enter the pressing gap through the air channel, affecting the accurate monitoring of the pressure. Based on this, the present application sets the first airway as a stepped airway structure of the first sub-airway 111 and the second sub-airway 112, wherein the first sub-airway 111 is used for the normal circulation of airflow, and the second sub-airway 112 is at the end of the first sub-airway 111. By reducing the size of the second sub-airway 112, it is difficult for external dust or powder to enter the interior of the sensor, thereby ensuring the stable operation of the sensor.

[0071] As an optional embodiment of the present invention, a second air channel is also connected between each third through hole in the present application, and each first air channel connects the second air channel to the outside. In addition to the form of connecting a single third through hole to the first air channel, the present application can also connect each third through hole by setting a second air channel, and then set the first air channel on the second air channel to complete the connection between the pressing gap and the external space. By using the form of the first air channel and the second air channel, the opening of the first air channel can be kept away from the area where the sensitive layer 5 is located, which can not only realize the connection between the sensor and the outside, but also make the sensitive layer 5 away from the opening area where the sensor is connected to the outside, and minimize the probability of external dust and the like contacting the sensitive layer 5, ensuring the accuracy of pressure monitoring. Optionally, since the second air channel here connects each third through hole as a whole, the first air channel in the present application can be set to one or more, which can realize the connection between each pressing gap and the external space.

[0072] As an alternative embodiment of the present invention, a fourth through hole 13 is formed in the first adhesive layer 6 in the present application. The fourth through hole 13 forms an embedding area in the first adhesive layer 6. Each sensitive layer 5 is respectively attached to the embedding area, and the embedding area communicates with the outside through a first air passage. In addition to the form of providing a third through hole in the first adhesive layer 6 and connecting the third through hole with a second air passage, the present application can also adopt the form of providing a fourth through hole 13 in the first adhesive layer 6 and arranging all the sensitive layers 5 in the embedding area formed by the fourth through hole 13. Adopting this form can significantly reduce the processing time of the first adhesive layer 6, but during the preparation process of the sensor, the sensitive layer 5 and the sensing area 4 of the electrode layer 2 need to be strictly aligned.

[0073] As an alternative embodiment of the present invention, the flexible pressure sensor in the present application further includes a second encapsulation layer 10, which is arranged on the side of the pressing layer 9 away from the first encapsulation layer 7; and a second adhesive layer 14 is provided between the pressing layer 9 and the first encapsulation layer 7, and a third adhesive layer 15 is provided between the pressing layer 9 and the second encapsulation layer 10. A hard gasket 8 is embedded in the pressing layer 9. In order to ensure the overall stability of the flexible pressure sensor, a second encapsulation layer 10 is arranged on the side of the pressing layer 9 away from the first encapsulation layer 7. The second encapsulation layer 10 encapsulates the pressing layer 9 and the hard gasket 8 inside the sensor. At the same time, the second encapsulation layer 10 and the base layer 1 form an outer protection structure of the flexible pressure sensor. Correspondingly, in order to ensure the stable connection of each layer and make each layer of the sensor an integral body, glue is used for bonding between the layers to ensure the stable use of the pressure sensor.

[0074] Further, as an alternative embodiment of the present invention, the base layer 1, the first encapsulation layer 7, and the second encapsulation layer 10 in the present application are PET (polyethylene terephthalate) films or PI (polyimide) films, and both have excellent high and low temperature resistance, electrical insulation, adhesiveness, radiation resistance, chemical resistance, etc. Of course, in addition to PET films or PI films, other film structures with good weather resistance can also be used as the base layer 1, the first encapsulation layer 7, or the second encapsulation layer 10.

[0075] As an alternative embodiment of the present invention, the adhesive in the present application is OCA optical adhesive. OCA optical adhesive is a special adhesive for bonding transparent optical elements. It has the characteristics of colorless transparency, light transmittance above 95%, good bonding strength, curable at room temperature or medium temperature, and small curing shrinkage, etc., which can ensure the high-precision preparation of the pressure sensor in the present application.

[0076] As an alternative embodiment of the present invention, the electrode layer 2 in the present application is prepared by screen-printing silver paste material, the insulating layer 3 is prepared by screen-printing ink material, and the sensitive layer 5 is prepared by screen-printing carbon paste material. In addition, the hard gasket 8 in the present application can be made of iron sheet, copper sheet, aluminum sheet or acrylic board, which has a certain hardness and can accurately conduct pressure to the sensitive layer 5 and the electrode layer 2 when stressed, so as to change the resistance of the electrode layer 2 and complete the pressure monitoring.

[0077] As an alternative embodiment of the present invention, the thicknesses of the base layer 1, the first encapsulation layer 7 and the second encapsulation layer 10 in the present application are between 0.1 and 0.2 mm, preferably 0.15 mm; the thickness of the insulating layer 3 is between 10 and 15 μm, preferably 15 μm; and the thicknesses of each adhesive layer are between 0.08 and 0.12 mm, preferably 0.1 mm; the thickness of the pressing layer 9 is between 0.2 and 0.3 mm, preferably 0.25 mm. Here, the relatively thick thickness of the pressing layer 9 is convenient for the setting of the hard gasket 8, so that the hard gasket 8 does not protrude from the pressing layer 9. And since the hard gasket 8 is mostly made of metal sheet, to ensure that the hard gasket 8 does not deform during pressing, it needs to have a certain thickness. Correspondingly, the thickness of the hard gasket 8 is the same as the selected thickness of the pressing layer 9, and the range of both is 0.2 to 0.3 mm. Further optionally, the thicknesses of the electrode layer 2 and the sensitive layer 5 in the present application are both 6 to 10 μm, preferably 8 μm. The two are prepared by printing using the same process and have the same thickness.

[0078] It should be noted that the thickness of the pressure sensor itself in the present application is relatively thin, and the thickness of the first adhesive layer 6 is only between 0.08 and 0.12 mm. In order to ensure the stable formation of the first channel 11, the second channel 12, etc. on the first adhesive layer 6, the present application uses a laser cutting process to form a channel structure on the first adhesive layer 6.

[0079] Furthermore, as an alternative embodiment of the present invention, for the flexible pressure sensor for automotive seats in the present application, the present application also includes a preparation method for the flexible pressure sensor for automotive seats, which includes the following steps:

[0080] S1. Select a flexible film with a set thickness as the base layer 1, the first encapsulation layer 7, the pressing layer 9 and the second encapsulation layer 10;

[0081] S2. Screen-print silver paste wires on the surface of the base layer 1 to prepare and form the electrode layer 2;

[0082] S3. Print insulating paste on the surface of the electrode layer 2 to cover the silver paste wires to form the insulating layer 3, and partially expose and reserve the induction area 4 on the circuit of the silver paste wires; the insulating layer 3 is mainly used to cover the conduction area of the electrode layer 2 to ensure that after the induction area 4 and the sensitive layer 5 are in contact, the pressure is converted into an electrical signal and conducted to an external signal processing device through the electrode layer 2.

[0083] S4, screen-printing carbon-based slurry on the surface of the first packaging layer 7 to form a sensitive layer 5, and cutting the OCA glue into a set shape and attaching it to the surface of the first packaging layer 7 so that the sensitive layer 5 is exposed;

[0084] S5. Cut the OCA adhesive layer by laser cutting to form a channel of a set size; the set shape formed by cutting the OCA adhesive here means that the OCA adhesive will not cover the sensitive layer 5 and the sensing area 4. It is worth noting that in this preparation method, the OCA adhesive layer is attached to the surface of the first packaging layer 7 and then the channel is formed by laser cutting. During the laser processing, the laser cutting power needs to be strictly controlled to ensure that the first channel 11 is cut into the set width size and to avoid damaging the sensitive layer 5 and the first packaging layer 7 during the laser cutting process.

[0085] S6, attaching the first packaging layer 7 to the base layer 1 so that the sensitive layer 5 is arranged toward the sensing area 4 of the electrode layer 2;

[0086] S7, cutting a circular hole structure on the pressing layer 9, attaching the pressing layer 9 to the side of the first packaging layer 7 away from the insulating layer 3, and attaching a hard gasket 8 to the circular hole area of ​​the pressing layer 9;

[0087] S8 , connecting the interface of the electrode layer 2 to the interface of the back-end signal processing circuit, and attaching the second packaging layer 10 to the side of the pressing layer 9 facing away from the first packaging layer 7 .

[0088] The preparation method of the flexible pressure sensor for automobile seats in the present application covers the electrode layer 2 with an insulating layer 3, and only exposes the sensing area 4 of the electrode layer 2 to ensure the normal use of the pressure sensing circuit inside the sensor. Then, a sensitive layer 5 is set corresponding to the sensing area 4, and the insulating layer 3 reserves a pressing gap between the sensitive layer 5 and the sensing area 4. When the sensitive layer 5 is subjected to force, it will move toward the sensing area 4. The contact area between the sensitive layer 5 and the sensing area 4 reflects the pressure, thereby realizing the perception of pressure. At the same time, the present application forms a set size channel on the first adhesive layer 6 by laser cutting, so that the pressing gap is connected to the outside, avoiding the expansion or contraction of the pressing gap of the pressure sensor in a cold or hot environment, ensuring the accurate perception of pressure by the sensitive layer 5 and the sensing area 4, and the present application embeds a hard gasket 8 structure on the pressing layer 9. The pressing layer 9 itself has a flexible and foldable characteristic to avoid the sensor affecting the driver's riding experience. The hard gasket 8 structure is set corresponding to the sensitive layer 5 and the sensing area 4, so that the external pressure is accurately transmitted to the sensitive layer 5, ensuring the accurate perception of pressure by the pressure sensor.

[0089] It is worth noting that the electrode layer 2 and the insulating layer 3 in the present application are formed on the base layer 1, and the sensitive layer 5 in the present application is formed on the first packaging layer 7; when the two are aligned and bonded, the base layer 1 is first fixed by a vacuum adsorption mechanism, and then the OCA photosensitive adhesive is cut so that the OCA adhesive and the sensitive layer 5 avoid each other, and then the OCA adhesive is adhered to the surface of the first packaging layer 7, and then the first air channel is formed by laser cutting, and finally the first packaging layer 7 is attached to the surface of the insulating layer 3. Here, the OCA photosensitive adhesive needs to avoid the positions of the sensing area 4 and the sensitive layer 5 during the cutting process, so as to ensure the connection between the pressing gap and the outside, and the stable contact between the sensing area 4 and the sensitive layer 5, so as to ensure the accuracy of pressure monitoring.

[0090] Further, as an optional embodiment of the present invention, with respect to the flexible pressure sensor for a car seat in the present application, the present application also includes a method for preparing the flexible pressure sensor for a car seat, which comprises the following steps:

[0091] S1, selecting a flexible film of set thickness as the base layer 1, the first encapsulation layer 7, the pressing layer 9 and the second encapsulation layer 10;

[0092] S2, screen printing silver paste wire on the surface of the substrate layer 1 to prepare a formed electrode layer 2;

[0093] S3, printing insulating paste on the surface of the electrode layer 2 to cover the silver paste wire to form an insulating layer 3, and partially exposing the silver paste wire to reserve a sensing area 4;

[0094] S4, screen printing a carbon-based slurry on the surface of the first encapsulation layer 7 to form a sensitive layer 5;

[0095] S5, using laser cutting to cut a hole of a set size on the surface of the OCA adhesive layer, and attaching the OCA adhesive layer to the surface of the first packaging layer 7, so that the sensitive layer 5 is exposed;

[0096] S6, attaching the first packaging layer 7 to the base layer 1 so that the sensitive layer 5 is arranged toward the sensing area 4 of the electrode layer 2;

[0097] S7, cutting a circular hole structure on the pressing layer 9, attaching the pressing layer 9 to the side of the first packaging layer 7 away from the insulating layer 3, and attaching a hard gasket 8 to the circular hole area of ​​the pressing layer 9;

[0098] S8 , connecting the interface of the electrode layer 2 to the interface of the back-end signal processing circuit, and attaching the second packaging layer 10 to the side of the pressing layer 9 facing away from the first packaging layer 7 .

[0099] As another preparation method of the present invention, this preparation method mainly changes the way of cutting the first adhesive layer 6 originally attached to the first encapsulation layer 7 to form an air channel structure. By previously cutting an avoidance space for the sensitive layer 5 and an air channel structure on the first adhesive layer 6, the separate cutting form of the first adhesive layer 6 avoids damage to other layers of the sensor during laser cutting, can reduce the laser cutting precision, speed up the production efficiency of the first adhesive layer 6, and improve the overall preparation efficiency of the pressure sensor.

[0100] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A flexible pressure sensor for a car seat, characterized in that: include: A base layer, an electrode layer disposed on the base layer, the surface of the electrode layer is covered with an insulating layer, a plurality of first through holes are formed on the insulating layer, and the sensing areas of the electrode layer are disposed corresponding to the first through holes; a first packaging layer, wherein the first packaging layer, the insulating layer and the base layer form a pressing gap, a plurality of sensitive layers are arranged in the first packaging layer, the sensitive layers are arranged in the pressing gap, and the sensing areas of the sensitive layers and the electrode layers convert pressure signals into electrical signals through a piezoresistive effect; A pressing layer, the pressing layer is arranged on the side of the first packaging layer away from the insulating layer, the pressing layer is made of a flexible material, and a plurality of second through holes are opened on the pressing layer, the plurality of second through holes are arranged in one-to-one correspondence with the plurality of first through holes, and a hard gasket is embedded in each of the second through holes, and the sensing areas of the hard gasket, the sensitive layer and the electrode layer are aligned in the thickness direction of the sensor; A first adhesive layer is further provided between the first encapsulation layer and the insulating layer, a plurality of third through holes are opened on the first adhesive layer, and the sensitive layer is provided in the third through holes; The first adhesive layer is provided with at least one first air channel in a circumferential direction along the sensitive layer, and the first air channel connects the pressing gap with the outside.

2. The flexible pressure sensor for a car seat according to claim 1, characterized in that: The first air channel comprises a first sub-air channel and a second sub-air channel which are arranged in sequence in a direction away from the sensitive layer; The first sub-airway connects the pressing gap and the second sub-airway, and the width of the first sub-airway is 1-2 mm; The second sub-air channel connects the first sub-air channel with the outside, and the width of the second sub-air channel is 0.01-0.2 mm.

3. The flexible pressure sensor for a car seat according to claim 1, characterized in that: A second air channel is connected between each of the third through holes, and each of the first air channels connects the second air channel with the outside.

4. The flexible pressure sensor for a car seat according to claim 1, characterized in that: A fourth through hole is provided in the first adhesive layer, and the fourth through hole forms an embedded area in the first adhesive layer. Each of the sensitive layers is attached to the embedded area, and the embedded area is connected to the outside through the first air channel.

5. The flexible pressure sensor for a car seat according to claim 1, characterized in that: It also includes a second encapsulation layer, which is arranged on a side of the pressing layer away from the first encapsulation layer; A second adhesive layer is provided between the pressing layer and the first packaging layer, and a third adhesive layer is provided between the pressing layer and the second packaging layer.

6. The flexible pressure sensor for a car seat according to claim 5, characterized in that: The base layer, the first encapsulation layer and the second encapsulation layer are PET films or PI films; The first adhesive layer, the second adhesive layer and the third adhesive layer are OCA optical adhesives; The electrode layer is made of silver paste material, the insulating layer is made of ink material, and the sensitive layer is made of carbon paste material; The hard gasket is made of iron sheet, copper sheet, aluminum sheet or acrylic sheet.

7. The flexible pressure sensor for a car seat according to claim 5, characterized in that: The thickness of the base layer, the first encapsulation layer and the second encapsulation layer is 0.1-0.2 mm; The thickness of the insulating layer is 10-15 μm, the thickness of the first adhesive layer, the second adhesive layer and the third adhesive layer are all 0.08-0.12 mm, the thickness of the pressing layer is 0.2-0.3 mm, the thickness of the electrode layer is 6-10 μm, and the thickness of the sensitive layer is 6-10 μm.

8. A method for preparing a flexible pressure sensor for a car seat, characterized in that: The steps include: S1, selecting a flexible film of set thickness as the base layer, the first packaging layer, the pressing layer and the second packaging layer; S2, screen printing silver paste wire on the surface of the substrate layer to prepare a formed electrode layer; S3, printing insulating paste on the surface of the electrode layer to cover the silver paste wire to form an insulating layer, and partially exposing the silver paste wire to reserve a sensing area; S4, screen-printing carbon-based slurry on the surface of the first packaging layer to form a sensitive layer, and cutting the OCA glue into a set shape and attaching it to the surface of the first packaging layer so that the sensitive layer is exposed; S5, cutting the OCA adhesive layer into a hole of a set size by laser cutting; S6, attaching the first packaging layer to the base layer so that the sensitive layer is arranged toward the sensing area of ​​the electrode layer; S7, cutting a circular hole structure on the pressing layer, attaching the pressing layer to the side of the first packaging layer away from the insulating layer, and attaching a hard gasket to the circular hole area of ​​the pressing layer; S8, connecting the interface of the electrode layer to the interface of the back-end signal processing circuit, and attaching the second packaging layer to the side of the pressing layer away from the first packaging layer.

9. A method for preparing a flexible pressure sensor for a car seat, characterized in that: The steps include: S1, selecting a flexible film of set thickness as the base layer, the first packaging layer, the pressing layer and the second packaging layer; S2, screen printing silver paste wire on the surface of the substrate layer to prepare a formed electrode layer; S3, printing insulating paste on the surface of the electrode layer to cover the silver paste wire to form an insulating layer, and partially exposing the silver paste wire to reserve a sensing area; S4, screen printing a carbon-based slurry on the surface of the first encapsulation layer to form a sensitive layer; S5. Cutting a hole of a set size on the surface of the OCA adhesive layer by laser cutting, attaching the OCA adhesive layer to the surface of the first packaging layer, and exposing the sensitive layer; S6, attaching the first packaging layer to the base layer so that the sensitive layer is arranged toward the sensing area of ​​the electrode layer; S7, cutting a circular hole structure on the pressing layer, attaching the pressing layer to the side of the first packaging layer away from the insulating layer, and attaching a hard gasket to the circular hole area of ​​the pressing layer; S8, connecting the interface of the electrode layer to the interface of the back-end signal processing circuit, and attaching the second packaging layer to the side of the pressing layer away from the first packaging layer.

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