Flexible pressure sensor for automobile seat and preparation method thereof

Abstract

The invention discloses a flexible pressure sensor for an automobile seat and a preparation method thereof, and belongs to the technical field of flexible sensors, the flexible pressure sensor comprises a substrate layer and an electrode layer arranged on the substrate layer, the surface of the electrode layer is covered with an insulating layer, and a sensing area of the electrode layer is correspondingly exposed; a plurality of sensitive layers are arranged in the first packaging layer, and the sensitive layers and the sensing area of the electrode layer convert pressure signals into electric signals through the piezoresistive effect; the pressing layer is made of a flexible material, 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. The second through holes are formed in the pressing layer, the hard gaskets are embedded in the second through holes, the flexible pressing layer is matched with the hard gaskets, so that the whole sensor is flexible and convenient to bend, the riding experience of a driver is not affected, the hard gaskets can serve as stress carriers and cannot deform due to stress, and the service life of the sensor is prolonged. And accurate monitoring of the pressure is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of flexible sensors, and in particular relates to a flexible pressure sensor for a car seat and a preparation method thereof. Background Art

[0002] In recent years, with the continuous development of new energy technologies, the number of cars has also continued to surge. Among the car parts, car seats are key components that affect the driver's driving experience and monitoring status. Monitoring the pressure distribution on the car seat helps to accurately grasp the driver's driving habits, provide support for adjusting the car seat status and improving the driving experience. At the same time, monitoring the pressure status of the car seat during driving can also accurately judge the driver's driving status, and can provide intervention or reminders in dangerous situations such as driver fatigue driving, aggressive driving or distracted driving, so as to reduce the occurrence of traffic accidents and protect the driver's life and property safety.

[0003] The interior of the car seat is mainly filled with flexible sponge materials. Conventional hard pressure sensors placed in the car seat will reduce the driver's riding experience. Although the conventional flexible sensor structure will not affect the driver's riding experience, when the human body is sitting, the flexible pressure sensor will often be compressed and deformed along with the sponge material, causing inaccurate pressure detection by the pressure sensor, resulting in poor pressure detection effect and inability to accurately detect the pressure distribution of the car seat. Summary of the invention

[0004] In view of one or more of the above defects or improvement needs of the prior art, the present invention provides a flexible pressure sensor for a car seat, so as to solve the problem that the existing flexible pressure sensor cannot accurately detect the pressure distribution of the car seat.

[0005] To achieve the above object, the present invention provides a flexible pressure sensor for a car seat, comprising: A base layer, an electrode layer disposed on the base layer, wherein the surface of the electrode layer is covered with an insulating layer; The insulating layer is provided with a plurality of first through holes, and the sensing area of ​​the electrode layer is arranged corresponding to each of 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, 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.

[0006] 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; 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.

[0007] 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; 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.

[0008] 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.

[0009] 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.

[0010] 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; 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.

[0011] 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; 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.

[0012] 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; 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.

[0013] The present application also includes a method for preparing a flexible pressure sensor for a car seat, which comprises the following steps: 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.

[0014] The present application also includes a method for preparing a flexible pressure sensor for a car seat, which comprises the following steps: 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.

[0015] The above-mentioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0016] In general, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects: (1) The flexible pressure sensor for a car seat of the present invention forms an electrode layer on a base layer, and then covers most of the circuits of the electrode layer with an insulating layer, and only reserves part of the sensing area through a first through hole, and then arranges a sensitive layer on the first packaging layer, and forms a pressing gap between the sensing area and the sensitive layer through the first through hole. When the sensor is subjected to external force, the sensitive layer moves toward the sensing area. When the two contact, the resistance value of the electrode layer changes accordingly and reflects the pressure change in the form of an electrical signal, thereby realizing pressure sensing. At the same time, the present application arranges a pressing layer on the back of the first packaging layer, and the pressing layer is also made of a flexible material, and a pressing layer is arranged on the pressing layer. A second through hole is formed, and a hard gasket is embedded in the second through hole. Through the cooperation of the pressing layer and the hard gasket, the sensor as a whole is flexible and easy to bend, and does not affect the driver's riding experience; secondly, the sensing areas of the hard gasket, the sensitive layer and the electrode layer are arranged correspondingly, so that when the sensor is subjected to force, the hard gasket serves as a force carrier for the sensing areas of the sensitive layer and the electrode layer, and will not be deformed due to the force, so that the pressure perception of the sensor is accurately reflected, and the hard gasket can constrain the sensor structure in the area to avoid problems such as wrinkles in the sensing area and the sensitive layer, so as to ensure that the flexible pressure sensor for the car seat accurately monitors the pressure.

[0017] (2) The flexible pressure sensor for a car seat of the present invention has a first air channel opened on the first adhesive layer, and uses the first air channel to connect the external space with the pressing gap, so that the air pressure inside and outside the sensor is balanced, ensuring accurate pressure sensing of the pressure sensor.

[0018] (3) The flexible pressure sensor for automobile seats of the present invention, since the sensing area and the sensitive layer of the electrode layer 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 airway, affecting the accurate monitoring of pressure. Based on this, the present application sets the first airway as a stepped airway structure of the first sub-airway and the second sub-airway, wherein the first sub-airway is used for the normal circulation of the airflow, and the second sub-airway is at the end of the first sub-airway. By reducing the size of the second sub-airway, it is difficult for external dust or powder to enter the sensor, so as to ensure the stable operation of the sensor.

[0019] (4) The flexible pressure sensor for automobile seats of the present invention adopts the form of cooperation between the first air channel and the second air channel, so that the first air channel can be kept away from the area where the sensitive layer is located, which can not only realize the connection between the pressing gap of the sensor and the outside, but also make the sensitive layer away from the opening area where the sensor is connected to the outside, thereby reducing the probability of external dust and the like contacting the sensitive layer as much as possible, thereby ensuring the accuracy of pressure monitoring.

[0020] (5) The preparation method of the flexible pressure sensor for automobile seats of the present invention covers the electrode layer with an insulating layer, and only exposes the sensing area of ​​the electrode layer, so as to ensure the normal operation of the pressure sensing circuit inside the sensor. Then, a sensitive layer is set in the corresponding sensing area, and a pressing gap is reserved between the sensitive layer and the sensing area. When the sensitive layer is subjected to force, it moves toward the sensing area. The contact area between the sensitive layer and the sensing area 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 by laser cutting, so that the pressing gap is connected to the outside, thereby avoiding the expansion or contraction of the pressing gap of the pressure sensor in hot and cold environments, thereby ensuring the accurate perception of pressure by the sensitive layer and the sensing area. In addition, the present application embeds a hard gasket structure on the pressing layer, and the pressing layer itself has flexible and foldable characteristics, thereby preventing the sensor from affecting the driver's riding experience. The hard gasket structure is set in correspondence with the sensitive layer and the sensing area, so that the external pressure is accurately transmitted to the sensitive layer, thereby ensuring the accurate perception of pressure by the pressure sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the overall structure of a flexible pressure sensor for a car seat in an embodiment of the present invention; Figure 2 is a schematic cross-sectional structure diagram of a flexible pressure sensor for a car seat in an embodiment of the present invention; Figure 3 is a schematic structural diagram of a first adhesive layer in one embodiment of the present invention; Figure 4 is a schematic diagram of the structure of the first channel in an embodiment of the present invention; Figure 5is a schematic structural diagram of a first adhesive layer in one embodiment of the present invention; Figure 6 It is a schematic structural diagram of the first adhesive layer in one embodiment of the present invention.

[0022] In all the drawings, the same reference numerals represent the same technical features, specifically: 1. Base layer; 2. Electrode layer; 3. Insulating layer; 4. Sensing area; 5. Sensitive layer; 6. First adhesive layer; 7. First packaging layer; 8. Hard gasket; 9. Pressing layer; 10. Second packaging layer; 11. First channel; 12. Second channel; 13. Fourth through hole; 14. Second adhesive layer; 15. Third adhesive layer; 111. First sub-airway; 112. Second sub-airway. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is 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 intended 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.

[0024] In the description of the present invention, it should be understood that, unless otherwise specified, terms such as “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0025] In addition, unless otherwise specified, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0026] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] 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.

[0028] Example: See also Figures 1 to 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.

[0029] Specifically, the present application forms an electrode layer 2 on a base layer 1, and then covers most of the circuits of the electrode layer 2 with an insulating layer 3, reserving only a portion of the sensing area 4 through a first through hole, and then arranges a sensitive layer 5 on a first packaging layer 7, and forms a pressing gap between the sensing area 4 and the sensitive layer 5 through the first through hole. When the sensor is subjected to external force, the sensitive layer 5 moves toward the sensing area 4. When the two are in contact, the resistance value of the electrode layer 2 changes accordingly and reflects the pressure change in the form of an electrical signal, thereby realizing pressure sensing. At the same time, the present application sets a pressing layer 9 on the back side of the first packaging layer 7, and the pressing layer 9 is also made of flexible material. A second through hole is set on the pressing layer 9, and a hard gasket 8 is embedded in the second through hole. Through the cooperation between the pressing layer 9 and the hard gasket 8, the sensor as a whole is flexible and easy to bend without affecting the driver's riding experience; secondly, the hard gasket 8, the sensitive layer 5 and the sensing area 4 of the electrode layer 2 are set in correspondence, so that when the sensor is subjected to force, the hard gasket 8 serves as a force carrier for the sensitive layer 5 and the sensing area 4 of the electrode layer 2, and it will not be deformed due to the force, so that the pressure perception of the sensor is accurately reflected, so as to ensure the accurate monitoring of pressure by the flexible pressure sensor for the car seat.

[0030] Specifically, the first packaging layer 7, the insulating layer 3 and the base layer 1 in the present application constitute a pressing gap, which means that after the three are stacked, the first packaging 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.

[0031] 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 in the present application, and a plurality of third through holes are correspondingly provided on the first adhesive layer 6, and each sensitive layer 5 is arranged in the third adhesive layer 15, and the first adhesive layer 6 is provided with at least one first air channel circumferentially along the sensitive layer 5, and the first air channel connects 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 the present application is mainly used for car seats, which are enclosed inside the car body. Due to the uncertainty of the car's use environment, when the outside temperature is high, the temperature inside the car is also high. After the flexible pressure sensor is heated, the internal space of the pressing gap expands due to the heat, causing the flexible pressure sensor to deform and bulge as a whole, resulting in inaccurate pressure sensing monitoring. Based on this, the present application corresponds to setting a first adhesive layer 6, which can bond the first packaging layer 7 and the insulating layer 3 together, and the first air channel on the first adhesive layer 6 can connect the external space with the pressing gap, so that the internal and external air pressures are balanced, ensuring accurate perception of the pressure of the pressure sensor.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] As an optional embodiment of the present invention, a fourth through hole 13 is provided in the first adhesive layer 6 in the present application, and the fourth through hole 13 forms an embedded area in the first adhesive layer 6, and each sensitive layer 5 is respectively attached to the embedded area, and the embedded area is connected to the outside through the first air channel. In addition to the above-mentioned form of setting the third through hole in the first adhesive layer 6 and connecting the third through hole with the second air channel, the present application can also adopt the form of setting the fourth through hole 13 in the first adhesive layer 6, and arranging all the sensitive layers 5 in the embedded area formed by the fourth through hole 13. The use of this form can greatly reduce the processing time of the first adhesive layer 6, but the sensitive layer 5 and the sensing area 4 of the electrode layer 2 must be strictly aligned during the sensor preparation process.

[0036] As an optional embodiment of the present invention, the flexible pressure sensor in the present application also includes a second packaging layer 10, which is arranged on the side of the pressing layer 9 away from the first packaging layer 7; and a second glue layer 14 is provided between the pressing layer 9 and the first packaging layer 7, and a third glue layer 15 is provided between the pressing layer 9 and the second packaging 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 packaging layer 10 is provided on the side of the pressing layer 9 away from the first packaging layer 7. The second packaging layer 10 encapsulates the pressing layer 9 and the hard gasket 8 inside the sensor, and the second packaging layer 10 and the base layer 1 constitute the outer protective structure of the flexible pressure sensor. Correspondingly, in order to ensure the stable connection of each layer and make the sensor layers become one, glue is used to bond the layers to ensure the stable use of the pressure sensor.

[0037] Further, as an optional 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) film or PI (polyimide) film, both of which have excellent high and low temperature resistance, electrical insulation, adhesion, radiation resistance, dielectric resistance, etc. Of course, in addition to PET film or PI film, 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.

[0038] As an optional embodiment of the present invention, the glue in this application is OCA optical glue. OCA optical glue is a special adhesive used to bond transparent optical elements. It is colorless and transparent, has a transmittance of more than 95%, and has good bonding strength. It can be cured at room temperature or medium temperature and has small curing shrinkage, which can ensure the high-precision preparation of the pressure sensor in this application.

[0039] As an optional embodiment of the present invention, the electrode layer 2 in the present application is made of screen-printed silver paste material, the insulating layer 3 is made of screen-printed ink material, and the sensitive layer 5 is made of screen-printed 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 plate, which has a certain hardness and can accurately transmit pressure to the sensitive layer 5 and the electrode layer 2 when subjected to force, so as to achieve the change of resistance of the electrode layer 2 and complete pressure monitoring.

[0040] As an optional embodiment of the present invention, the thickness of the base layer 1, the first encapsulation layer 7 and the second encapsulation layer 10 in the present application is 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 thickness of each adhesive layer is 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. The relatively thick thickness of the pressing layer 9 here is to facilitate the setting of the hard gasket 8, so that the hard gasket 8 does not protrude from the pressing layer 9, and because the hard gasket 8 is mostly made of metal sheets, in order 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 thickness of the pressing layer 9, and the range is 0.2 to 0.3 mm. Further optionally, in the present application, the electrode layer 2 and the sensitive layer 5 have a thickness of 6-10 μm, preferably 8 μm, and are printed and prepared using the same process and have the same thickness.

[0041] It is worth noting that the pressure sensor 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 forming 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.

[0042] 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: 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; S2, screen printing silver paste wire on the surface of the substrate layer 1 to prepare a formed electrode layer 2; S3. Insulating paste is printed on the surface of the electrode layer 2 to cover the silver paste wire to form an insulating layer 3, and a sensing area 4 is partially exposed on the line of the silver paste wire; the insulating layer 3 is mainly used to cover the conductive area of ​​the electrode layer 2 to ensure that after the sensing area 4 and the sensitive layer 5 are in contact, the pressure is converted into an electrical signal and transmitted to the external signal processing equipment through the electrode layer 2.

[0043] 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; 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.

[0044] 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; 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; 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 .

[0045] 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.

[0046] 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.

[0047] 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: 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; S2, screen printing silver paste wire on the surface of the substrate layer 1 to prepare a formed electrode layer 2; 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; S4, screen printing a carbon-based slurry on the surface of the first encapsulation layer 7 to form a sensitive layer 5; 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; 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; 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; 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 .

[0048] 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 packaging layer 7 to form the airway structure. By cutting the first adhesive layer 6 in advance to form the avoidance space and the airway structure of the sensitive layer 5, the first adhesive layer 6 is cut separately to avoid damage to other layers of the sensor during laser cutting, which can reduce the laser cutting accuracy, speed up the production efficiency of the first adhesive layer 6, and improve the overall preparation efficiency of the pressure sensor.

[0049] It will be easily understood by those skilled in the art 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 substitutions and improvements made within the spirit and principles of the present invention should be included in 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, 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.

2. The flexible pressure sensor for a car seat according to claim 1, characterized in that: 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.

3. The flexible pressure sensor for a car seat according to claim 2, 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.

4. The flexible pressure sensor for a car seat according to claim 2, 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.

5. The flexible pressure sensor for a car seat according to claim 2, 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.

6. 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.

7. The flexible pressure sensor for a car seat according to claim 6, 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.

8. The flexible pressure sensor for a car seat according to claim 6, 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.

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 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.

10. 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.

Images