RU2577915C1 - Method of making multilayer film contact sensor - Google Patents

Abstract

FIELD: manufacturing technology.

SUBSTANCE: proposed method relates to production of multilayered film contact threshold pressure sensors and can be used in making multilayer contact threshold pressure sensors fixed on the surface of measured objects. Method of making multilayer film contact sensor involves making of at least two layers, one of which is made from flexible dielectric material sensitive to pressure, on which a second layer made of current-conducting element is formed by photochemical etching with the use of photomasks, subsequent assembly of sensor element obtain a package from alternating dielectric and conductive layers, connecting elements in the package under conditions of thermocompression welding. Assembly is compressed by means of two auxiliary flexible elements, which after pressure release are removed and a sensor circuit is formed. One of the auxiliary elastic elements is used in the form of metal mesh laid on both sides with film from thermosetting polymer. Besides, on the side opposite to the package, before film from thermosetting polymer the film from thermoplastic polymer is placed. For isolation of contacts on the current-conducting layers of different sensor levels thermoplastic polymer is used which is laid between thermosetting films laminated with thermoplastic polymer before thermocompression welding and removed before final formation of the sensor contour.

EFFECT: proposed method consists in avoiding effects such as twisting, warpage and displacement of the conductive pattern on different layers of the sensor relative to each other.

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Description

The invention relates to the field of instrumentation, and in particular to the manufacturing technology of multilayer film contact sensors of threshold pressure, and can be used in the manufacture of film contact sensors fixed on the surface of the measured objects.

A known method of manufacturing a contact sensor, including the implementation of at least two layers, each of which contains a first layer made of flexible dielectric material, pressure-sensitive, on which a second layer of a conductive element of a given circuit is formed, the subsequent assembly of the sensor element with obtaining a packet of alternating the first and second layers, the formation of two dielectric layers as the walls of the sensor housing, laminated on only one side adjacent to the package, using two two auxiliary elastic elements, at least one of which is made of metal rubber (patent RU No. 2166740, IPC G01L 7/08 of 05/10/2001).

The disadvantage of the technical solution is the low resistance of the sensor to shock and vibration during its operation due to the fact that the sensor on the installation side of the measured object has a corrugated surface due to the use of a layer of metal rubber for crimping the assembly, and, therefore, the bond strength of the sensor with the measured surface is not high.

The closest analogue to the claimed technical solution is a method of manufacturing a multilayer contact sensor in the form of a layered film (patent RU No. 2411473, MPK G01L 7/08 of 02/10/2011), comprising the implementation of at least two layers, one of which is made from a flexible dielectric material that is sensitive to pressure and is a thermosetting polymer laminated on both sides with a thermoplastic polymer on which a second layer of a conductive element is formed, followed by assembly of the sensor element with the floor the study of a package of alternating dielectric and conductive layers, the connection of elements in a package under thermocompression welding with the preliminary placement of the package between two dielectric layers of a thermosetting polymer - a polyimide film, laid on the side of the package with a thermoplastic polymer - polyethylene.

The disadvantage of the prototype is the impossibility of crimping the conductive pattern laminated with a thermosetting film on one side, and ensuring a smooth surface on the back of the sensor, as well as the offset of the conductive pattern on different layers of the sensor relative to each other.

The problem to which the claimed technical solution is directed is to create such a device that would provide compression of the conductive pattern laminated with a thermosetting polymer during thermocompression welding on the one hand, the formation of a smooth surface on the other hand, and would also avoid undesirable effects such as twisting, warping and shifting the conductive pattern on different layers of the sensor relative to each other.

The solution to this problem lies in the fact that the method of manufacturing a multilayer contact sensor, comprising performing at least two layers, one of which is made of a flexible dielectric material that is pressure sensitive and is a thermosetting polymer laminated on both sides with a thermoplastic polymer, which form the second layer of the conductive element by photochemical etching using a set of photomasks, the subsequent assembly of the sensor element with the package of alternating dielectric and conductive layers, the connection of elements in a package under conditions of thermocompression welding with the preliminary placement of the package between two dielectric layers of thermosetting polymer used as the walls of the housing, laminated with a thermoplastic polymer only from the side adjacent to the package, while for compression the assemblies use two auxiliary elastic elements, which, after relieving the pressure, remove and finally form the sensor circuit corresponding to the configuration of the measured object, moreover, as one of the auxiliary elastic elements, a metal mesh is used, laid on both sides with a film of a thermosetting polymer, and on the side opposite the package, a film of a thermoplastic polymer is placed in front of the film of a thermosetting polymer, in addition, to isolate the contacts on conductive layers of different levels of the sensor use a thermoplastic polymer that is laid between thermoset films laminated with thermoplastic polymer m, before thermocompression welding and is removed before the final formation of the sensor circuit.

In addition, the metal mesh has a mesh size of 0.2-0.4 mm and a thread thickness of 0.1-0.2 mm.

In addition, thermostated polyimide is used as the thermosetting polymer surrounding the metal mesh.

In addition, polyethylene is used as the thermoplastic polymer located in front of the thermosetting polymer film.

In addition, the number of layers of the thermosetting polymer surrounding the metal mesh on the side of the bag is in the range from 1 to N, where N is an integer.

In addition, all films of thermosetting polymer used in the manufacture of the sensor are subjected to temperature control at 150 ° C for 30 minutes

In addition, fluoroplastic is used as a thermoplastic polymer that insulates the contacts of the conductive layers of different levels of the sensor before thermocompression welding.

In addition, a polyimide is used as a thermosetting polymer laminated with a thermoplastic polymer.

In the process of manufacturing a multilayer film contact sensor, two conductive layers 1 through a thermosetting film 2 of polyimide, laminated on both sides with a thermoplastic film of fluoroplastic, are subjected to thermo-compression welding, which is carried out in a vacuum press (not shown) under the influence of temperature and pressure (Fig. 1) . After that, a pattern of sensor elements is formed on the conductive layers by photochemical etching using a set of photomasks. After obtaining the picture, the workpiece is re-subjected to thermocompression welding between thermosetting films 3 of polyimide laminated with a thermoplastic film of fluoroplastic only from the side adjacent to the workpiece of the sensor, also in a vacuum press under the influence of temperature and pressure. After thermocompression welding, the sensor is cut to the required dimensions using a laser system.

Unlike the prototype, in the process of repeated thermocompression welding, a press pad device is used to compress the conductive layers of film contact sensors, including:

- thermoplastic film 4 of polyethylene, which serves as a medium for pressure transmission and in the process of thermocompression welding of the film sensor goes into a thermoplastic state, which contributes to the compression of the conductive pattern;

- a metal mesh 5 with a mesh size of 0.2-0.4 mm and a filament thickness of 0.1-0.2 mm, which provides a uniform distribution of pressure on the surface of the sensor and prevents stretching of the dielectric layer from the thermosetting film 2, which allows avoid twisting the finished sensor, in addition, the metal mesh 5 prevents the displacement of the conductive pattern on different layers relative to each other;

- thermosetting film 6 of polyimide, laid on both sides of the metal mesh 5, which withstands high temperatures of thermocompression welding and prevents leakage and adhesion of thermoplastic film 6 of polyethylene, which is in the process of welding in the molten state.

The dimensions of the mesh cells were chosen experimentally, as maximally ensuring the solution of the problem, and stainless steel was chosen as the mesh material, as the material that does not change its physical properties during thermocompression welding

The polyethylene film is selected as the material that transfers pressure to the conductive layers of the film sensors, due to its low softening temperature (80-120 ° C), which ensures uniform pressure distribution over the entire surface of the film sensors under thermal compression conditions.

Thermostated polyimide is selected as the material surrounding the metal mesh, since the polyimide treated at a temperature of 150 ° C for 30 minutes has low shrinkage.

It was also experimentally established that the number of layers of a film 8 of a thermosetting polymer - polyimide surrounding the metal grid 7 on the side of the film sensor pack depends on the size of the mesh cell, so for a mesh with a cell size of 0.2 mm, one film layer is optimal, and for mesh with a mesh size of 0.4 mm, three layers of film are optimal; with an increase in the number of film layers, the effect of compression of the conductive layers 1 by the grid 7 decreases, and with a decrease in the number of film layers, dents from the grid 7 may appear on the conductive layers 1, which is unacceptable by the design documentation for the film sensors.

With this manufacturing method, the device of the press pillows is used only on the side on which the conductive pattern of the sensor laminated with a thermosetting polymer must be crimped, while the second side of the sensor, also laminated with a thermosetting polymer, is formed as a smooth surface, the result of using the device of press pillows is the absence twisting during the final formation of the sensor circuit.

The metal mesh can be used repeatedly, as it does not lose its original properties.

Thus, the technical result of the proposed method for manufacturing a multilayer film contact sensor using a press pad device containing a metal mesh is the compression of a conductive pattern laminated with a thermosetting polymer during thermocompression welding on the one hand and providing a smooth surface on the other, which avoids such undesirable effects like twisting, warping, and shifting the conductive pattern on different layers of the sensor but each other.

The proposed method of manufacturing a multilayer contact film sensor is introduced in mass production.

Claims (8)

1. A method of manufacturing a multilayer film contact sensor, comprising the implementation of at least two layers, one of which is made of a flexible dielectric material that is pressure sensitive and is a thermosetting polymer laminated on both sides with a thermoplastic polymer on which a second layer of conductive element by photochemical etching using a set of photomasks, the subsequent assembly of the sensor element to obtain a packet of alternating dielectric conductive layers, the connection of elements in a package under thermocompression welding with preliminary placement of the package between two dielectric layers of thermosetting polymer used as housing walls, laminated with thermoplastic polymer only from the side adjacent to the package, while using two to compress the assembly auxiliary elastic elements, which, after depressurization, remove and finally form the sensor circuit corresponding to the configuration of the measured object, exl characterized in that, as one of the auxiliary elastic elements, a metal mesh is used, laid on both sides with a film of a thermosetting polymer, and on the side opposite to the bag, a film of a thermoplastic polymer is placed in front of the film of a thermosetting polymer; in addition, to isolate the contacts on the conductive layers of different levels of the sensor, a thermoplastic polymer is used, which is laid between thermoset films laminated with a thermoplastic polymer before thermocompression welding and is removed before the final formation of the sensor circuit. 2. The method according to p. 1, characterized in that the metal mesh has a mesh size of 0.2-0.4 mm, and the thickness of the thread is 0.1-0.2 mm 3. The method according to p. 1, characterized in that as the thermosetting polymer surrounding the metal mesh, polyimide is used. 4. The method according to p. 1, characterized in that as a thermoplastic polymer located in front of the film of thermosetting polymer, polyethylene is used. 5. The method according to p. 3, characterized in that the number of layers of a thermosetting polymer adjacent to the metal mesh from the side of the packet varies from 1 to N, where N is an integer. 6. The method according to p. 1, characterized in that all films of a thermosetting polymer used in the manufacture of the sensor are subjected to temperature control at 150 ° C for 30 minutes 7. The method according to p. 1, characterized in that as a thermoplastic polymer, insulating the contacts of the conductive layers of different levels of the sensor before thermocompression welding, fluoroplastic is used. 8. The method according to p. 1, characterized in that as the thermosetting polymer laminated with a thermoplastic polymer, a polyimide is used.

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