A production method of a flexible film backline pressure sensor

Abstract

The invention relates to a production method of a flexible film backline pressure sensor, comprising the following steps: installing a PET base film and setting an oven temperature, installing a silver paste line screen, an ink scraper and an ink return knife, setting a feeding speed of the PET base film and preheating the PET base film, and then sequentially coating a silver paste line layer, an insulating layer, a secondary brushing insulating layer, a silver paste strip layer, a carbon paste layer and a glue layer on the preheated PET base film. By limiting the mesh count of the insulating screen and secondary coating of the insulating layer, it is possible to effectively ensure that the insulating layer completely covers the silver paste line layer and can basically completely cover the generated bubbles, greatly reducing the phenomenon of multi-point linkage force during pressure testing, ensuring the overall molding quality and molding efficiency of the flexible film backline pressure sensor, and greatly reducing the defect rate of the finished product, and ensuring the accuracy and efficiency of the flexible film backline pressure sensor in the later use process, convenience and practicality.

Description

Technical Field

[0001] The invention relates to the field of flexible backline pressure sensors, and in particular to a production method of a flexible film backline pressure sensor. Background Art

[0002] Flexible backline thin film pressure sensor is a sensor that can detect pressure changes. It is usually composed of flexible substrate materials, pressure-sensitive nano-functional materials and electrodes. This sensor can convert external pressure signals into physical signals that are easy to detect, such as resistance, voltage, capacitance, etc., to test absolute pressure values ​​or pressure changes.

[0003] The flexible backline sensor is composed of a PET protective layer, a silver paste line layer, an insulating layer, a silver paste strip layer, a carbon paste layer and a glue layer. The backline sensor needs to be force tested after production. During the test of the existing flexible backline sensor, when force is applied to a certain sensing point, other sensing points that are not subjected to force will also be subjected to force, thereby affecting the overall detection efficiency and quality, which is very inconvenient. Summary of the invention

[0004] The purpose of the present invention is to provide a production method of a flexible thin film backline pressure sensor with an ingenious structure. The silver paste layer is completely covered by setting the mesh number of the insulating screen and applying the insulating paste twice, thereby effectively avoiding the linkage between the silver paste layers, and then effectively solving the problem of linkage of the force points. The method is efficient and practical.

[0005] The technical solution to achieve the purpose of the present invention is: the present invention relates to a method for producing a flexible film backline pressure sensor, comprising the following steps:

[0006] S1. Preliminary preparation: install the PET base film on the screen printing machine, turn on the oven and set the preheating temperature;

[0007] S2. Component installation: Install the silver paste screen, ink scraper and ink return knife;

[0008] S3. Setting parameters: setting the feeding speed of the PET base film to 150 mm / s;

[0009] S4, making a silver paste line layer: feeding the PET base film, preheating it in an oven, pouring the silver paste on the silver paste line screen, scraping it flat with a scraper, and returning the ink with an ink return knife. The PET base film coated with the silver paste is returned to the oven for drying and winding, and the silver paste line screen is removed;

[0010] S5, making the insulating layer: replace the new scraper and ink return knife, install the insulating screen, the mesh number of the insulating screen is 280~300 mesh, feed the PET base film with the silver paste line layer, pour the insulating slurry into the insulating screen, scrape it flat with the scraper, and return the ink with the ink return knife. The PET base film coated with the insulating slurry is returned to the oven for drying and rewinding;

[0011] S6, secondary coating of insulating layer: the PET base film coated with the insulating layer once is loaded, the insulating slurry is poured in again, the film is scraped flat by a scraper, and the ink is returned by an ink return knife. The PET base film coated with the insulating slurry is returned to the oven for drying and rewinding, and the insulating screen is removed;

[0012] S7, making a silver paste stripe layer: replace a new scraper and ink return knife, install the silver paste stripe screen, feed the PET base film coated with two layers of insulating layer, pour the silver paste into the silver paste stripe screen, scrape it flat with the scraper, and return the ink with the ink return knife, return the PET base film coated with silver paste to the oven for drying and winding, and remove the silver paste stripe screen;

[0013] S8, making a carbon slurry layer: replace a new scraper and ink return knife, install a carbon layer screen, feed the PET base film coated with a silver paste strip layer, pour the carbon slurry onto the carbon layer screen, scrape it flat with a scraper, and return the ink with an ink return knife, return the PET base film coated with carbon slurry to the oven for drying and winding, and remove the carbon layer screen;

[0014] S9, making glue layer: replace new scraper and ink return knife, install glue layer screen, feed the PET base film coated with carbon slurry layer, pour glue into the glue layer screen, scrape it flat with scraper, and return ink with ink return knife, return the glued PET base film to the oven for drying and winding, and remove the glue layer screen;

[0015] S10, loop production: according to the operation steps of S1 to S9, the front film layer and the back film layer of the sensor are repeatedly produced;

[0016] S11, sensor molding: cutting the TAB area on the front film layer and the back film layer, and then bonding the front film layer and the back film layer through a glue layer to form a flexible thin film backline pressure sensor, and then cutting the whole to form a single flexible thin film backline pressure sensor;

[0017] S12, post-test: test the backline pressure sensor of the cut flexible film.

[0018] Furthermore, the preheating temperature of the oven is greater than the drying temperature of the silver paste line layer, the insulating layer, the secondary coated insulating layer, the silver paste strip layer, the carbon paste layer and the glue layer, and the preheating temperature of the oven is 160-200 degrees Celsius.

[0019] Furthermore, the drying temperature of the above-mentioned oven for the silver paste line layer, the insulating layer, the secondary coated insulating layer, the silver paste strip layer, the carbon paste layer and the glue layer is 60-150° C., and the drying time is 7-40 minutes.

[0020] Furthermore, the scraping speed of the above-mentioned scraper is set to 130~150mm / s, and the ink returning speed of the ink returning knife is set to 300~350mm / s.

[0021] Furthermore, the hardness of the scraper is 70-85HRC.

[0022] Furthermore, the silver paste line screen, insulating screen, silver paste strip screen, carbon layer screen, glue layer screen, and each scraper and ink return knife are cleaned immediately after being removed and set aside for use.

[0023] Furthermore, the model of the above-mentioned screen printing machine is LC-CCDR8080SYJ-B.

[0024] The present invention has positive effects: (1) The present invention sets a preheating temperature on the oven and preheats the PET base film, thereby effectively avoiding heat shrinkage and curling of the PET base film during the later slurry process. The feeding speed of the PET base film is set to ensure the stable feeding of the PET base film and avoid the problem of uneven printing of the PET base film caused by feeding too fast or too slow. The silver paste line layer can be completely covered by limiting the number of meshes of the insulating screen and brushing the insulating layer twice. If the insulating layer is only brushed once, the ink scraper is not horizontally scraped or bubbles are easily generated during the scraping process, and the insulating layer cannot completely cover the silver paste line layer. The thickness of the insulating layer is 4 to 8 microns, which causes a short circuit between the silver paste line layer and the silver paste strip layer. If the insulating slurry is brushed more than twice, the thickness of the insulating layer is too thick, and it will be difficult to apply the silver paste strip layer. At the same time, brushing the insulating slurry multiple times may also press the bubbles in the insulating layer to burst, which again causes a short circuit between the silver paste line layer and the silver paste strip layer.

[0025] In addition, the existing flexible film backline pressure sensor will have the problem of linkage of force points when performing pressure testing, that is, when a force test is performed at one point, other points will also be stressed. In the field of sensors, when the linkage problem occurs, because the silver paste line layer and the silver paste strip layer both function as conductors, the silver paste line layer or the silver paste strip layer of the sensor is generally tested, and the insulation layer is not tested.

[0026] The mesh number of the insulation screen is set between 280 and 300 meshes. When the mesh number of the insulation screen is too small, the diameter of the mesh hole is too large, which will increase the area of ​​contact with the air when printing the insulation screen, increasing the probability and number of bubbles generated. When the mesh number of the insulation screen is too large, it may cause poor ink fluidity, slow printing speed, increase costs, and too high a mesh number will waste resources.

[0027] Therefore, limiting the mesh range of the insulating screen and the number of printing times of the insulating layer can effectively solve the problem of multiple-point pressure on the flexible film backline sensor during force detection in the prior art. Printing twice can effectively ensure that the insulating layer completely covers the silver paste line layer during the printing process, avoiding the short circuit problem between the silver paste line layer and the silver paste strip layer due to the generation of bubbles, thereby ensuring the accuracy of force detection of the flexible film backline pressure sensor, efficient and convenient.

[0028] (2) The present invention can effectively prevent the PET base film from shrinking and deforming during the later slurry or drying process by setting the preset temperature of the oven to be greater than the drying temperature of the oven for the silver paste line layer, the insulating layer, the secondary coated insulating layer, the silver paste strip layer, the carbon paste layer and the glue layer, thereby ensuring the integrity of the PET base film during the later processing. At the same time, it also ensures the accuracy of the later PET base film when the silver paste line layer, the insulating layer, the silver paste strip layer, the carbon paste layer and the glue layer are coated in sequence, which is efficient and practical.

[0029] (3) The present invention sets the drying time and drying temperature, and sets the drying temperature to be lower than the preheating temperature, thereby ensuring that the PET base film will not shrink and deform, and also ensuring that each coated slurry can be completely dried and thoroughly dried, thereby avoiding the coated slurry from not drying due to too low a drying temperature or too short a drying time, which affects the loading of the next layer of slurry, and also avoiding the problem of embrittlement and fracture of the coated silver paste line layer, insulating layer, silver paste strip layer, carbon paste layer and glue layer due to too long a drying time. The present invention is safe and practical.

[0030] (4) The present invention can effectively ensure that various slurries can be completely printed and excess ink can be removed during the printing process by setting the speed of the ink scraper and the ink return knife. At the same time, the limitation of the printing speed can avoid incomplete printing caused by printing too fast, and can also avoid the risk of ink becoming smeared due to printing too slowly. It is efficient and convenient.

[0031] (5) The present invention can effectively ensure the scraping of the slurry by setting the hardness of the scraper to 70~85HRC. If the hardness exceeds this range, the scraper will cause pressure and wear on each screen due to excessive hardness, and the complete printing of the slurry cannot be guaranteed. If the hardness is below this range, the scraper is too soft to apply force to the slurry, and the integrity of the printing cannot be guaranteed.

[0032] (6) The present invention can effectively prevent the slurry from sticking to the screen by immediately cleaning each removed screen, and also facilitates the reciprocating use of each screen, which is convenient and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments and in conjunction with the accompanying drawings, wherein

[0034] Figure 1 An exploded view of the overall structure of the flexible film backline pressure sensor of the present invention;

[0035] Figure 2 It is a schematic diagram of the case where the insulating layer does not completely cover the silver paste line layer in the present invention. DETAILED DESCRIPTION

[0036] (Example 1)

[0037] See Figure 1 to Figure 2 The present invention relates to a method for producing a flexible film backline pressure sensor, comprising the following steps:

[0038] S1. Preliminary material preparation: Install the PET base film 1 on the screen printing machine, turn on the oven and set the preheating temperature;

[0039] S2. Component installation: Install the silver paste screen, ink scraper and ink return knife;

[0040] S3. Setting parameters: Setting the feeding speed of the PET base film 1 to 150 mm / s. The setting of the feeding speed ensures smooth feeding of the PET base film 1 and avoids the PET base film 1 being fed too fast or too slow to affect the uniformity of the overall printing;

[0041] S4, making silver paste line layer 2: feeding PET base film 1, preheating it in an oven, pouring silver paste on the silver paste line screen, scraping it flat with a scraper, and returning the ink with an ink return knife, returning the PET base film 1 coated with silver paste to the oven for drying and winding, and removing the silver paste line screen;

[0042] S5, making the insulating layer 3: replacing a new scraper and ink return knife, installing an insulating screen, the mesh number of the insulating screen is 280 meshes, feeding the PET base film 1 with the silver paste line layer 2, pouring the insulating slurry into the insulating screen, scraping it flat with the scraper, and returning the ink with the ink return knife, and returning the PET base film 1 coated with the insulating slurry to the oven for drying and winding;

[0043] S6, secondary coating of the insulating layer 3: the PET base film 1 coated with the insulating layer 3 is loaded, the insulating slurry is poured in again, the film is scraped flat by a scraper, and the ink is returned by an ink return knife. The PET base film 1 coated with the insulating slurry is returned to the oven for drying and winding, and the insulating screen is removed;

[0044] S7, making a silver paste stripe layer 4: replacing a new scraper and ink return knife, installing a silver paste stripe screen, feeding the PET base film 1 coated with two layers of insulating layer 3, pouring the silver paste into the silver paste stripe screen, scraping it flat with a scraper, and performing ink return treatment with an ink return knife, returning the PET base film 1 coated with silver paste to an oven for drying and winding, and removing the silver paste stripe screen;

[0045] S8, making a carbon slurry layer 5: replacing a new scraper and ink return knife, installing a carbon layer screen, feeding the PET base film 1 coated with a silver paste strip layer 4, pouring the carbon slurry onto the carbon layer screen, scraping it flat with a scraper, and performing ink return treatment with an ink return knife, returning the PET base film 1 coated with carbon slurry to an oven for drying and winding, and removing the carbon layer screen;

[0046] S9, making glue layer 6: replace new scraper and ink return knife, install glue layer 6 screen, feed the PET base film 1 coated with carbon slurry layer 5, pour glue into the glue layer 6 screen, scrape it flat with the scraper, and return the ink with the ink return knife, return the glued PET base film 1 to the oven for drying and winding, and remove the glue layer 6 screen;

[0047] S10, loop production: follow the operation steps of S1 to S9 to copy and produce the front film layer and the back film layer of the sensor; the front film layer and the back film layer have different vertical and horizontal circuit arrangements, so the silver paste line screen and silver paste strip screen used in the production of the back film layer are different from the screen used in the production of the front film layer;

[0048] S11, sensor molding: cutting the TAB area on the front film layer and the back film layer, and then bonding the front film layer and the back film layer through the glue layer 6 to form a flexible film backline pressure sensor, and then cutting the whole to form a single flexible film backline pressure sensor;

[0049] S12, post-test: test the backline pressure sensor of the cut flexible film.

[0050] The preheating temperature of the oven is greater than the drying temperature of the silver paste line layer 2, the insulating layer 3, the secondary coated insulating layer 3, the silver paste strip layer 4, the carbon paste layer 5 and the glue layer 6, and the preheating temperature of the oven is 160 degrees Celsius.

[0051] The preheating temperature is set to be greater than the drying temperature of the oven, and the PET base film 1 is preheated when it is first fed. This can ensure that the PET base film 1 will not shrink or curl during the subsequent printing of various slurries and the slurry during the drying process, thereby ensuring the integrity of the flexible film backline pressure sensor after molding, which is efficient and practical.

[0052] The oven has a drying temperature of 150° C. for the silver paste line layer 2 , the insulating layer 3 , the secondary-coated insulating layer 3 , the silver paste strip layer 4 , the carbon paste layer 5 and the glue layer 6 , and the drying time is 7 minutes.

[0053] The setting of the baking time and baking temperature of the oven can ensure that the silver paste line layer 2, the insulating layer 3, the secondary coated insulating layer 3, the silver paste strip layer 4, the carbon paste layer 5 and the glue layer 6 on the PET base film 1 can be completely dried and baked, avoiding the problem that each paste is not completely dried due to the high temperature and is mixed with the paste of the next layer, and also avoiding the problem of embrittlement due to excessive temperature, easy cracking or breakage.

[0054] The scraping speed of the ink scraper is set to 130 mm / s, and the ink return speed of the ink return knife is set to 300 mm / s.

[0055] The hardness of the scraper is 70HRC.

[0056] The settings of the speed and hardness of the scraper blade can prevent the slurry from adhering to each screen and causing incomplete printing. It can also avoid the problem of the slurry being too wet, resulting in poor and blurred printing effects, thereby ensuring printing efficiency and quality.

[0057] The silver paste line screen, insulating screen, silver paste strip screen, carbon layer screen, glue layer 6 screen, and each scraper and ink return knife are cleaned immediately after being removed and then standby for use.

[0058] The model of the screen printing machine is LC-CCDR8080SYJ-B.

[0059] During the printing process of the screen printing machine, the ambient temperature is maintained at 25 degrees Celsius and the humidity is 40%. If the environment is too dry, the slurry will adhere to each screen and affect the printing effect of the slurry. If the environment is too humid, the slurry will gradually blur after printing, affecting the overall printing effect, which is very inconvenient.

[0060] The present invention can completely cover the silver paste line layer 2 by limiting the number of meshes of the insulating screen and brushing the insulating layer 3 twice. If the insulating layer 3 is only brushed once, the ink scraper is not horizontally scraped or it is easy to contact with air during the scraping process to generate bubbles P, and the insulating layer 3 cannot completely cover the silver paste line layer 2. The thickness of the insulating layer 3 is 4 to 8 microns, which causes a short circuit between the silver paste line layer 2 and the silver paste strip layer 4. If the insulating paste is brushed more than twice, the thickness of the insulating layer 3 is too thick, and it will be difficult to apply the silver paste strip layer 4, the carbon paste layer 5 and the glue layer 6. At the same time, brushing the insulating paste multiple times may also press the bubbles P in the insulating layer 3 to burst, which again causes a short circuit between the silver paste line layer 2 and the silver paste strip layer 4.

[0061] In addition, the existing flexible film backline pressure sensor will have the problem of linkage of force points when performing pressure testing, that is, when a force test is performed at one point, other points will also be stressed. In the field of sensors, when the linkage problem occurs, because the silver paste line layer 2 and the silver paste strip layer 4 both function as conductors, generally the silver paste line layer 2 or the silver paste strip layer 4 of the sensor is tested, and the insulating layer 3 is not tested.

[0062] The mesh number of the insulation screen is set between 2 and 80 meshes. When the mesh number of the insulation screen is too small, the diameter of the mesh hole is too large, which will increase the area of ​​contact with the air when printing the insulation screen, increasing the probability and number of bubbles P. When the mesh number of the insulation screen is too large, it may cause poor ink fluidity, slow printing speed, increase costs, and too high a mesh number will waste resources.

[0063] The mesh size of the insulating screen and the number of printings of the insulating layer 3 are the main factors that affect the multi-point force occurrence of the flexible film backline pressure sensor during the detection process. Therefore, the limitation of the mesh size range of the insulating screen and the number of printings of the insulating layer 3 can effectively solve the problem of multi-point pressure occurrence of the flexible film backline sensor during force detection in the prior art. The two printings can effectively ensure that the insulating layer 3 completely covers the silver paste line layer 2 during the printing process, avoiding the short circuit problem between the silver paste line layer 2 and the silver paste strip layer 4 caused by the generation of bubbles P, thereby ensuring the accuracy of the force detection of the flexible film backline pressure sensor, efficient and convenient.

[0064] (Example 2)

[0065] See Figure 1 to Figure 2 The present invention relates to a method for producing a flexible film backline pressure sensor, comprising the following steps:

[0066] S1. Preliminary material preparation: Install the PET base film 1 on the screen printing machine, turn on the oven and set the preheating temperature;

[0067] S2. Component installation: Install the silver paste screen, ink scraper and ink return knife;

[0068] S3. Setting parameters: Setting the feeding speed of the PET base film 1 to 200 mm / s. The setting of the feeding speed ensures smooth feeding of the PET base film 1 and avoids the PET base film 1 being fed too fast or too slow to affect the uniformity of the overall printing;

[0069] S4, making silver paste line layer 2: feeding PET base film 1, preheating it in an oven, pouring silver paste on the silver paste line screen, scraping it flat with a scraper, and returning the ink with an ink return knife, returning the PET base film 1 coated with silver paste to the oven for drying and winding, and removing the silver paste line screen;

[0070] S5, making the insulating layer 3: replacing a new scraper and ink return knife, installing an insulating screen, the mesh number of the insulating screen is 280 meshes, feeding the PET base film 1 with the silver paste line layer 2, pouring the insulating slurry into the insulating screen, scraping it flat with the scraper, and returning the ink with the ink return knife, and returning the PET base film 1 coated with the insulating slurry to the oven for drying and winding;

[0071] S6, secondary coating of the insulating layer 3: the PET base film 1 coated with the insulating layer 3 is loaded, the insulating slurry is poured in again, the film is scraped flat by a scraper, and the ink is returned by an ink return knife. The PET base film 1 coated with the insulating slurry is returned to the oven for drying and winding, and the insulating screen is removed;

[0072] S7, making a silver paste stripe layer 4: replacing a new scraper and ink return knife, installing a silver paste stripe screen, feeding the PET base film 1 coated with two layers of insulating layer 3, pouring the silver paste into the silver paste stripe screen, scraping it flat with a scraper, and performing ink return treatment with an ink return knife, returning the PET base film 1 coated with silver paste to an oven for drying and winding, and removing the silver paste stripe screen;

[0073] S8, making a carbon slurry layer 5: replacing a new scraper and ink return knife, installing a carbon layer screen, feeding the PET base film 1 coated with a silver paste strip layer 4, pouring the carbon slurry onto the carbon layer screen, scraping it flat with a scraper, and performing ink return treatment with an ink return knife, returning the PET base film 1 coated with carbon slurry to an oven for drying and winding, and removing the carbon layer screen;

[0074] S9, making glue layer 6: replace new scraper and ink return knife, install glue layer 6 screen, feed the PET base film 1 coated with carbon slurry layer 5, pour glue into the glue layer 6 screen, scrape it flat with the scraper, and return the ink with the ink return knife, return the glued PET base film 1 to the oven for drying and winding, and remove the glue layer 6 screen;

[0075] S10, loop production: follow the operation steps of S1 to S9 to copy and produce the front film layer and the back film layer of the sensor; the front film layer and the back film layer have different vertical and horizontal circuit arrangements, so the silver paste line screen and silver paste strip screen used in the production of the back film layer are different from the screen used in the production of the front film layer;

[0076] S11, sensor molding: cutting the TAB area on the front film layer and the back film layer, and then bonding the front film layer and the back film layer through the glue layer 6 to form a flexible film backline pressure sensor, and then cutting the whole to form a single flexible film backline pressure sensor;

[0077] S12, post-test: test the backline pressure sensor of the cut flexible film.

[0078] The preheating temperature of the oven is greater than the drying temperature of the silver paste line layer 2, the insulating layer 3, the secondary coated insulating layer 3, the silver paste strip layer 4, the carbon paste layer 5 and the glue layer 6, and the preheating temperature of the oven is 200 degrees Celsius.

[0079] The preheating temperature is set to be greater than the drying temperature of the oven, and the PET base film 1 is preheated when it is first fed. This can ensure that the PET base film 1 will not shrink or curl during the subsequent printing of various slurries and the slurry during the drying process, thereby ensuring the integrity of the flexible film backline pressure sensor after molding, which is efficient and practical.

[0080] The oven has a drying temperature of 60° C. for the silver paste line layer 2 , the insulating layer 3 , the secondary-coated insulating layer 3 , the silver paste strip layer 4 , the carbon paste layer 5 and the glue layer 6 , and the drying time is 40 minutes.

[0081] The setting of the baking time and baking temperature of the oven can ensure that the silver paste line layer 2, the insulating layer 3, the secondary coated insulating layer 3, the silver paste strip layer 4, the carbon paste layer 5 and the glue layer 6 on the PET base film 1 can be completely dried and baked, avoiding the problem that each paste is not completely dried due to the high temperature and is mixed with the paste of the next layer, and also avoiding the problem of embrittlement due to excessive temperature, easy cracking or breakage.

[0082] The scraping speed of the ink scraper is set to 150 mm / s, and the ink return speed of the ink return knife is set to 350 mm / s.

[0083] The hardness of the ink scraper is 85HRC.

[0084] The settings of the speed and hardness of the scraper blade can prevent the slurry from adhering to each screen and causing incomplete printing. It can also avoid the problem of the slurry being too wet, resulting in poor and blurred printing effects, thereby ensuring printing efficiency and quality.

[0085] The silver paste line screen, insulating screen, silver paste strip screen, carbon layer screen, glue layer 6 screen, and each scraper and ink return knife are cleaned immediately after being removed and then standby for use.

[0086] The model of the screen printing machine is LC-CCDR8080SYJ-B.

[0087] During the printing process of the screen printing machine, the ambient temperature is maintained at 20 degrees Celsius and the humidity is 60%. If the environment is too dry, the slurry will adhere to each screen and affect the printing effect of the slurry. If the environment is too humid, the slurry will gradually blur after printing, affecting the overall printing effect, which is very inconvenient.

[0088] The present invention can completely cover the silver paste line layer 2 by limiting the number of meshes of the insulating screen and brushing the insulating layer 3 twice. If the insulating layer 3 is only brushed once, the ink scraper is not horizontally scraped or it is easy to contact with air during the scraping process to generate bubbles P, and the insulating layer 3 cannot completely cover the silver paste line layer 2. The thickness of the insulating layer 3 is 4 to 8 microns, which causes a short circuit between the silver paste line layer 2 and the silver paste strip layer 4. If the insulating paste is brushed more than twice, the thickness of the insulating layer 3 is too thick, and it will be difficult to apply the silver paste strip layer 4, the carbon paste layer 5 and the glue layer 6. At the same time, brushing the insulating paste multiple times may also press the bubbles P in the insulating layer 3 to burst, which again causes a short circuit between the silver paste line layer 2 and the silver paste strip layer 4.

[0089] In addition, the existing flexible film backline pressure sensor will have the problem of linkage of force points when performing pressure testing, that is, when a force test is performed at one point, other points will also be stressed. In the field of sensors, when the linkage problem occurs, because the silver paste line layer 2 and the silver paste strip layer 4 both function as conductors, generally the silver paste line layer 2 or the silver paste strip layer 4 of the sensor is tested, and the insulating layer 3 is not tested.

[0090] The mesh number of the insulation screen is set between 300 meshes. When the mesh number of the insulation screen is too small, the diameter of the mesh hole is too large, which will increase the area of ​​contact with the air when printing the insulation screen, increasing the probability and number of bubbles P. When the mesh number of the insulation screen is too large, it may cause poor ink fluidity, slow printing speed, increase costs, and too high a mesh number will waste resources.

[0091] The mesh size of the insulating screen and the number of printings of the insulating layer 3 are the main factors that affect the multi-point force occurrence of the flexible film backline pressure sensor during the detection process. Therefore, the limitation of the mesh size range of the insulating screen and the number of printings of the insulating layer 3 can effectively solve the problem of multi-point pressure occurrence of the flexible film backline sensor during force detection in the prior art. The two printings can effectively ensure that the insulating layer 3 completely covers the silver paste line layer 2 during the printing process, avoiding the short circuit problem between the silver paste line layer 2 and the silver paste strip layer 4 caused by the generation of bubbles P, thereby ensuring the accuracy of the force detection of the flexible film backline pressure sensor, efficient and convenient.

[0092] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for producing a flexible film backline pressure sensor, characterized in that The following steps are involved: S1. Preliminary preparation: install the PET base film on the screen printing machine, turn on the oven and set the preheating temperature; S2. Component installation: Install the silver paste screen, ink scraper and ink return knife; S3. Set parameters: set the feeding speed of PET base film to 150~200mm / s; S4, making a silver paste line layer: feeding the PET base film, preheating it in an oven, pouring the silver paste on the silver paste line screen, scraping it flat with a scraper, and returning the ink with an ink return knife. The PET base film coated with the silver paste is returned to the oven for drying and winding, and the silver paste line screen is removed; S5, making the insulating layer: replace the new scraper and ink return knife, install the insulating screen, the mesh number of the insulating screen is 280~300 mesh, feed the PET base film with the silver paste line layer, pour the insulating slurry into the insulating screen, scrape it flat with the scraper, and return the ink with the ink return knife. The PET base film coated with the insulating slurry is returned to the oven for drying and rewinding; S6, secondary coating of insulating layer: the PET base film coated with the insulating layer once is loaded, the insulating slurry is poured in again, the film is scraped flat by a scraper, and the ink is returned by an ink return knife. The PET base film coated with the insulating slurry is returned to the oven for drying and rewinding, and the insulating screen is removed; S7, making a silver paste stripe layer: replace a new scraper and ink return knife, install the silver paste stripe screen, feed the PET base film coated with two layers of insulating layer, pour the silver paste into the silver paste stripe screen, scrape it flat with the scraper, and return the ink with the ink return knife, return the PET base film coated with silver paste to the oven for drying and winding, and remove the silver paste stripe screen; S8, making a carbon slurry layer: replace a new scraper and ink return knife, install a carbon layer screen, feed the PET base film coated with a silver paste strip layer, pour the carbon slurry onto the carbon layer screen, scrape it flat with a scraper, and return the ink with an ink return knife, return the PET base film coated with carbon slurry to the oven for drying and winding, and remove the carbon layer screen; S9, making glue layer: replace new scraper and ink return knife, install glue layer screen, feed the PET base film coated with carbon slurry layer, pour glue into the glue layer screen, scrape it flat with scraper, and return ink with ink return knife, return the glued PET base film to the oven for drying and winding, and remove the glue layer screen; S10, loop production: according to the operation steps of S1 to S9, the front film layer and the back film layer of the sensor are repeatedly produced; S11, sensor molding: cutting the TAB area on the front film layer and the back film layer, and then bonding the front film layer and the back film layer through a glue layer to form a flexible thin film backline pressure sensor, and then cutting the whole to form a single flexible thin film backline pressure sensor; S12, post-test: test the backline pressure sensor of the cut flexible film.

2. The method for producing a flexible film backline pressure sensor according to claim 1, characterized in that: The preheating temperature of the oven is greater than the drying temperature of the silver paste line layer, the insulating layer, the secondary coated insulating layer, the silver paste strip layer, the carbon paste layer and the glue layer, and the preheating temperature of the oven is 160-200 degrees Celsius.

3. The method for producing a flexible film backline pressure sensor according to claim 2, characterized in that: The oven has a drying temperature of 60-150° C. for the silver paste line layer, the insulating layer, the secondary brushed insulating layer, the silver paste strip layer, the carbon paste layer and the glue layer, and the drying time is 7-40 minutes.

4. The method for producing a flexible film backline pressure sensor according to claim 1, characterized in that: The scraping speed of the ink scraper is set to 130-150 mm / s, and the ink return speed of the ink return knife is set to 300-350 mm / s.

5. The method for producing a flexible film backline pressure sensor according to claim 1, characterized in that: The hardness of the scraper is 70-85HRC.

6. The method for producing a flexible film backline pressure sensor according to claim 1, characterized in that: The silver paste line screen, insulating screen, silver paste strip screen, carbon layer screen, glue layer screen, and each scraper and ink return knife are cleaned immediately after being removed and are ready for use.

7. The method for producing a flexible film backline pressure sensor according to claim 1, characterized in that: The model of the screen printing machine is LC-CCDR8080SYJ-B.

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