Tape cable with sensor formed thereon and method of manufacturing

Abstract

A ribbon cable sensor assembly (2) has a ribbon cable (10) with respective individual wires (14). At least one sensor termination area (20) is positioned on the ribbon cable. The at least one sensor termination region has an insulating layer (24) removed from a respective individual wire (14) to provide an exposed individual conductor. Conductive material (26) is applied to respective exposed individual conductors in the at least one sensor termination region to form at least one sensor (12). A non-conductive material (30) may be applied to a sensor termination region on top of the conductive material.

Description

Technical Field

[0001] The present invention relates to a ribbon cable having one or more sensors formed or fabricated thereon and a method of making the same. Background Art

[0002] Electrical components such as sensors can be attached to wires or cables. One such example is the fabrication of a microthermocouple (MTC) sensor with a two-wire cable for a medical catheter. In such an application, the ends of the wires are manually stripped and then at the stripped ends of the cable, a heat shrink member or sheath can be applied for electrical insulation.

[0003] While the method described above is adequate for the termination of a single sensor, it is not possible to make multiple sensors at different locations on the same cable. In many applications, it may be beneficial to use multiple sensors spaced apart at different locations. One such application is MTC sensors at spaced apart locations in a conduit for multi-point temperature measurement. Currently, the spaced apart sensors are terminated on separate cables, bundled together and inserted into the conduit. This requires additional space inside the conduit and increases labor costs for the customer.

[0004] Therefore, it would be beneficial to provide a ribbon cable system having one or more sensors and a method of manufacturing the same. In particular, it would be beneficial to provide a system in which one or more sensors can be fabricated on a single ribbon cable or the like in a manner that minimizes space requirements and which can be fabricated through an automated process to reduce manufacturing and labor costs. Summary of the invention

[0005] The following provides a summary of certain illustrative embodiments of the invention. This summary is not an extensive overview and is not intended to identify key or critical aspects or elements of the invention or to delineate the scope thereof.

[0006] Aspects of the invention are applications of printed electronics technology for making micro-thermocouple (MTC) strip sensors. This can include using dispensing technology to precisely apply solder paste or silver ink to form micro-junctions, and using dispensing technology to apply a coating to encapsulate the micro-junctions for electrical insulation. Jetting is one such dispensing technology that can be used for low volume, high speed applications with high consistency.

[0007] Embodiments are directed to a ribbon cable sensor assembly having a ribbon cable with corresponding paired conductors. At least one sensor termination region is positioned on the ribbon cable. Electrical insulation layers of the at least one sensor termination region are removed from corresponding individual wires of the corresponding paired conductors to provide exposed individual conductors. Conductive material is applied to the corresponding exposed individual conductors in the at least one sensor termination region to form at least one sensor. Non-conductive material may be applied to the sensor termination region on top of the conductive material.

[0008] In various embodiments, the at least one sensor termination area is a plurality of sensor termination areas spaced apart along a longitudinal axis of the ribbon cable, and the at least one sensor is a plurality of sensors positioned in the plurality of sensor termination areas to allow the plurality of sensors to sense different locations along the ribbon cable.

[0009] Embodiments are directed to a method of manufacturing a ribbon cable sensor assembly having one or more sensors. The method includes: exposing individual conductors of the ribbon cable in defined areas by removing an electrical insulation layer in the defined areas; applying conductive ink on the exposed individual conductors of the cable in the defined areas to form sensors; and curing the conductive ink.

[0010] When reading and understanding the following detailed description of exemplary embodiments, additional features and aspects of the present invention will become apparent to those of ordinary skill in the art. As will be appreciated by those skilled in the art, other embodiments of the present invention are possible without departing from the scope and spirit of the present invention. Therefore, the drawings and associated descriptions are to be regarded as illustrative and non-restrictive in nature. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings, which are incorporated in and form a part of the specification, illustrate schematically one or more exemplary embodiments of the present invention and, together with the general description given above and the detailed description given below, serve to explain the principles of the present invention.

[0012] Figure 1 is a perspective view of a ribbon cable with multiple sensors at different locations on the cable.

[0013] Figure 2 is a diagram of a portion of the ribbon cable before the sensor is made on it.

[0014] Figure 3 is set to be adjacent to the laser Figure 2 A schematic diagram of a ribbon cable with a portion of its insulation removed to expose individual conductors, the ribbon cable being positioned adjacent to a printing press.

[0015] Figure 4 is a schematic diagram of a ribbon cable positioned adjacent a first printer, the ribbon cable having conductive ink deposited on exposed wires to form a sensor.

[0016] Figure 5 is a schematic diagram of a ribbon cable disposed adjacent to a second printer, the ribbon cable having a cured Figure 4 The conductive ink and the insulating material deposited over the cured conductive ink and exposed wires.

[0017] Figure 6 is a schematic diagram of a ribbon cable assembly positioned in a conduit.

[0018] Figure 7 It is a graphic manufacturing Figure 1 A flow chart of an illustrative method of a ribbon cable assembly having multiple sensors is shown in FIG.

[0019] Figure 8 is a perspective view of an alternative embodiment of a ribbon cable in which a sensor is fabricated at the end of the ribbon cable. DETAILED DESCRIPTION

[0020] The description of the illustrative embodiments according to the principles of the present invention is intended to be read in conjunction with the accompanying drawings, which are considered as part of the entire written description. In the description of the embodiments of the present invention disclosed herein, any reference to direction or orientation is intended only for the convenience of description and is not intended to limit the scope of the present invention in any way. Related terms, such as "lower", "upper", "horizontal", "vertical", "above", "below", "up", "down", "top" and "bottom" and their derivatives (e.g., "horizontal", "downward", "upward", etc.) should be interpreted as referring to the orientation as described then or as shown in the accompanying drawings under discussion. These related terms are only for the convenience of description, and unless so clearly indicated, the device is not required to be constructed or operated in a specific orientation. Unless otherwise clearly described, terms such as "attachment", "attachment", "connection", "connection", "interconnection" and the like refer to the relationship in which structures are fixed or attached to each other directly or indirectly through the intervention of intermediate structures and both removable or rigid attachments or relationships. In addition, the features and benefits of the present invention are illustrated by reference to preferred embodiments. Therefore, the present invention expressly should not be limited to such preferred embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features, the scope of the present invention being defined by the appended claims.

[0021] Exemplary embodiments of the present invention are now described with reference to the accompanying drawings. Reference numerals are used throughout the detailed description to refer to various elements and structures. Although the following detailed description contains many details for the purpose of illustration, it will be appreciated by those of ordinary skill in the art that many variations and modifications to the following details are within the scope of the present invention. Therefore, without losing the generality of the claimed invention and without imposing limitations on the claimed invention, the following embodiments of the present invention are described.

[0022] exist Figure 1 A multi-conductor ribbon cable sensor assembly 2 is shown in FIG. The multi-conductor ribbon cable sensor 2 is meant to be illustrative, as different configurations, different sizes, and different types of cables may be used.

[0023] Generally, a ribbon cable has a ribbonized cable or ribbon cable 10 with one or more sensors 12 formed or fabricated as individual conductors or wires 14 to pairs of conductors of the ribbon cable 10 at a sensor termination area 20. In the illustrative embodiment shown, six sensors 12 are electrically and mechanically formed on corresponding pairs of individual wires 14. The sensors 12 are spaced apart along a longitudinal axis 16 of the ribbon cable 10 to allow the sensors 12 to be used to sense different locations or areas. For example, the ribbon cable 10 may be positioned in a conduit 18 ( Figure 7 ), and the sensor 12 can be a temperature sensor to allow the temperature to be monitored at different multiple locations along the catheter 18.

[0024] Each sensor termination area has a conductor window 22 ( Figure 3 ), wherein the insulation layer 24 surrounding the two respective individual wires 14 of the paired conductor has been removed. The conductive material 26 ( Figure 4 ) is applied to the exposed conductors 14. The conductive material 26 is configured to mechanically and electrically engage with the corresponding wires 14 positioned in the corresponding sensor termination area 20. The conductive material 26 cooperates with the exposed conductors to form the sensor 12. The non-conductive or electrically insulating material 30 ( Figure 5 ) extends over the conductive material 26 and the exposed conductor 14 to seal or cover the conductive material 26 and the exposed conductor 14 in the conductor window 22 to protect and insulate the sensor 12 formed by the conductive material 26 and the exposed conductor 14.

[0025] refer to Figure 7, illustrates a general method 100 for creating a sensor termination area 20 in a ribbon cable 10 in a flow chart format. Initially, as represented in step 102, a conductor window 22 is created in the ribbon cable 10, thereby removing the insulation around the respective individual wires 14 of the ribbon cable 10. As represented in step 104, a conductive material 26 is applied to the exposed conductors 14 in the conductive window 22 to form the sensor 12. Then, as represented in step 106, the conductive material 26 is cured to provide a mechanical and electrical connection between the exposed conductors 14 in the conductor window 22. Then, as represented in step 108, a non-conductive or insulating material 30 is applied over the conductive material 26 and the conductor window 22. Then, as represented in step 110, the non-conductive or insulating material 30 is cured to provide a seal or covering to protect and insulate the sensor 12 formed by the conductive material 26 and the exposed conductors 14.

[0026] exist Figure 3 In the illustrative embodiment shown in , the conductor windows 22 are formed by a laser 50 to precisely remove the insulation around two respective individual wires 14 of the ribbon cable 10. This type of laser ablation can be used in an automated process to increase the yield of the finished multi-conductor ribbon cable sensor assembly 2. Other methods and apparatus for removing the insulation around the respective individual wires 14 of the ribbon cable 10 to form the conductor windows 22 can be used.

[0027] In the illustrative embodiment shown, the conductor window 22 is approximately 150 microns by approximately 400 microns. Other dimensions of the conductor window 22 may be used depending on the type of sensor to be used and the ultimate use of the multi-conductor ribbon cable sensor assembly 2.

[0028] With the conductor window 22 formed in the ribbon cable 10, the ribbon cable 10 is moved into position relative to the dispensing nozzle 52 of the print head, such as Figure 4 The dispensing nozzle 52 is aligned with the center of the pair of conductors 14 exposed in the corresponding conductor window 22.

[0029] The use of a printable electronic printer allows conductive material 26 to be precisely applied to the exposed pairs of conductors 14 in corresponding conductor windows 22. In particular, conductive material 26 may be applied such that conductive material 26 shorts the exposed pairs of conductors 14 to form microjunctions of sensor 12.

[0030] Various printing techniques (including but not limited to inkjet printing, contact extrusion dispensing, jet dispensing) can be used to apply the conductive material 26 through the dispensing nozzle 52. In the illustrated embodiment shown, the dispensing nozzle 52 is part of a jet dispensing system. In the case of jet dispensing, the dispensing nozzle or jet 52 hovers above the conductor window 22 and shoots the conductive material 26 above the conductor window 22 without ever contacting the exposed conductor 14. Therefore, the z-axis movement of the dispensing nozzle 52 can be eliminated for printing on the uneven or irregularly shaped surface of the ribbon cable 10. In addition, the dispensing nozzle or jet 52 produces extremely small size (for example, less than about 150 μm), low volume (for example, about 0.5 nL), high speed (for example, up to about 1000 points / second) and high consistency points. Although various jet dispensing nozzles 52 can be used, one example is the MDS3280 dispensing system available from VERMES Microdispensing GmbH. Dispensing is based on a piezoelectric actuator with a unique bayonet fluid cartridge that is better suited for mass production.

[0031] The dispensing nozzle 52 can have different configurations and different sizes of nozzle insert internal channels, which may affect the dispensing volume. In the illustrated embodiment, the nozzle insert has a conical internal channel, which promotes the acceleration of the conductive material 26 when exiting the dispensing nozzle 52, resulting in less accumulation of the conductive material 26 on the dispensing nozzle 52. The size of the tappet tip has an impact on the dispensing energy of the conductive material 26. In an illustrated embodiment, the nozzle insert has a channel of approximately 50 μm, and the tappet tip has a radius of approximately 5 μm to facilitate the dispensing of the conductive material 26.

[0032] exist Figure 4 In the embodiment shown in , two droplets of conductive material 26 are dispensed from the dispensing nozzle 52 onto the exposed wire pairs 14 in the corresponding conductor windows 22. In other embodiments, one, three or more than three droplets may be applied. The droplets may be as small as about 0.5 nL, which results in a droplet size of about 200 microns to 400 microns in diameter when applied to the exposed paired conductors 14. The droplets may be applied at a speed of up to about 500 dots / second without the need for z-axis motion for conformal printing. In other embodiments, the diameter of the dispensed conductive material 26 may be as low as about 150 microns.

[0033] In the illustrated embodiment shown, the conductive material 26 can be, but is not limited to, solder paste, silver ink, and gold ink. One example is nanosilver ink. The resistivity of the cured silver ink can vary, but in this illustrated embodiment, the resistivity is between about 0.01 mohm·cm and about 5 mohm·cm. The silver ink has silver particles with a diameter of about 0.3 microns or less. An illustrative example of a silver ink is HPS-FG77 silver ink, available from Nova Centrix Corporation. The silver ink can be diluted with a solvent (such as, but not limited to, butyl carbitol) between about 0.5% and about 3% to improve the self-leveling properties of the ink. The thickness of the cured silver trace was measured using a 3D optical profilometer. The thickness of the silver ink was between about 20 microns and about 30 microns.

[0034] In one illustrative embodiment, the jet dispensing process settings for the conductive material 26 have: a rise time from about 0.2 ms to about 0.3 ms; a fall time from about 0.1 ms to about 0.25 ms; and an open time from about 0.2 ms to about 0.4 ms; a needle valve lift from about 68% to about 72%; a nozzle height from about 1.8 mm to about 2 mm; a pressure from about 0.07 MPa to about 0.1 MPa; and a temperature from about 25°C to about 35°C.

[0035] Once applied, the dispensed conductive material 26 is cured. For example, silver ink may be cured for one hour at 90° C. Other temperatures and curing times may be used depending on the properties of the conductive material.

[0036] With the conductive material 26 properly applied and cured, the ribbon cable 10 is moved into position relative to the dispensing nozzle 54 of the print head, such as Figure 5 The dispensing nozzle 54 is aligned with the center of the dispensed conductive material 26 in the corresponding conductor window 22 .

[0037] Using the dispensing nozzle 54 of the print head allows the non-conductive or insulating material 30 to be precisely applied over the conductive material 26 in the corresponding conductor window 22. In particular, the non-conductive or insulating material 30 can be applied so that the non-conductive or insulating material 30 provides sufficient electrical insulation to protect the microjunctions of the sensor 12.

[0038] Various printing techniques (including but not limited to inkjet printing, contact extrusion dispensing, jet dispensing) can be used to apply the non-conductive or insulating material 30 through the dispensing nozzle 54. In the illustrative embodiment shown, the dispensing nozzle 54 is part of a jet dispensing system. In the case of jet dispensing, the dispensing nozzle or jet 54 hovers above the conductor window 22 and the conductive material 26, and the non-conductive or insulating material 30 is ejected above the conductor window 22 and the conductive material 26 without ever contacting the conductive material 26. Therefore, the z-axis movement of the dispensing nozzle 54 can be eliminated for printing on uneven or irregularly shaped surfaces of the ribbon cable 10. Although various jet dispensing systems can be used, an example is the MDS3280 dispensing system available from VERMES Microdispensing GmbH. Dispensing is based on a piezoelectric actuator with a unique bayonet fluid cartridge, which is more suitable for mass production.

[0039] The dispensing nozzle 54 can have different configurations and different sizes of the inner channel of the nozzle insert, which may affect the dispensing volume. In the illustrative embodiment, the nozzle insert has a conical inner channel, which promotes the acceleration of the non-conductive or insulating material 30 when exiting the dispensing nozzle 54, resulting in less accumulation of the non-conductive or insulating material 30 on the dispensing nozzle 54. The size of the tappet tip has an impact on the dispensing energy of the non-conductive or insulating material 30. In an illustrative embodiment, the nozzle insert has a nozzle insert of approximately 100 μm, and the tappet rod has a tip radius of approximately 7 μm to facilitate the dispensing of the non-conductive or insulating material 30.

[0040] exist Figure 5 In the embodiment shown in, three drops of non-conductive or insulating material 30 are dispensed from the dispensing nozzle 54 to the exposed pairs of conductors 14 in the conductive material 26 and the corresponding conductor windows 22. In other embodiments, one, two or more than three drops may be applied. When applied to the exposed pairs of conductors 14 in the conductive material 26 and the corresponding conductor windows 22, the drop size may be between about 250 microns to about 500 microns in diameter. In various embodiments, the coating thickness of the non-conductive or insulating material 30 is in the range of about 30 microns to 50 microns, wherein 3 drops of non-conductive or insulating material 30 are dispensed on the conductive material 26. In various embodiments, it may also be desirable to apply the non-conductive or insulating material 30 to the back side of the cable 10 at the conductor window 22 to provide electrical insulation.

[0041] In one illustrative embodiment, the jet dispensing process settings for the non-conductive or insulating material 30 have: a rise time from about 0.2 ms to about 0.3 ms; a fall time from about 0.1 ms to about 0.2 ms; and an open time from about 0.2 ms to about 0.3 ms; a needle valve lift from about 60% to about 80%; a delay from about 0.1 ms to about 0.2 ms; a nozzle height from about 1.8 mm to about 2 mm; a pressure from about 0.1 MPa to about 0.15 MPa; and a temperature from about 25°C to about 30°C.

[0042] In the illustrated embodiment shown, the non-conductive or insulating material 30 is a UV curable adhesive. An example of a UV curable adhesive is an acrylated urethane adhesive for medical devices from Dymax Corporation. The UV curable adhesive should be free of non-reactive solvents and cure when exposed to light.

[0043] Once applied, the dispensed non-conductive or insulating material 30 is cured. For example, the non-conductive or insulating material 30 may be cured using a 1.5 W / cm 2 Intensity and a spot UV lamp for about 5 seconds to about 20 seconds to cure.

[0044] Although Figures 1 to 6 The illustrative embodiment shown in FIG. 1 is directed to a ribbon cable 10 having multiple pairs of conductive cables and multiple sensors 12, but other embodiments may also be used. For example, Figure 8 An alternative embodiment is illustrated in which the ribbon cable 10' has two wires and a sensor termination area 20' is provided at the end of the ribbon cable 10'. Conductive material (not shown) and insulating material 30' are applied to the exposed conductor sensor termination area 20' in the same manner as previously described with respect to the ribbon cable 10 having multiple pairs of conductive cables and multiple sensors 12.

[0045] In a multi-conductor ribbon cable sensor assembly, a conductive material (e.g., silver ink) can be used to form the junction of the ribbonized MTC sensor. A printing technique (e.g., jet dispensing) is used to apply the conductive material to the laser-stripped wire windows of the ribbon cable, and then a UV-curable sealant is coated on the conductive material with high accuracy and repeatability. Printed electronics combined with precision laser ablation can achieve automated roll-to-roll mass production of multi-conductor MTC ribbon sensors.

[0046] Although the present invention has been described with reference to preferred embodiments, it will be appreciated by those skilled in the art that various changes may be made and that equivalents may be substituted for its elements without departing from the spirit and scope of the present invention as defined in the appended claims. It will be appreciated by those skilled in the art that the present invention may be used with many modifications of structure, arrangement, ratio, size, material and components and otherwise used in the practice of the present invention without departing from the principles of the present invention, the modifications being particularly adapted to specific environments and operability requirements. Therefore, the presently disclosed embodiments are considered in all respects to be illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims and is not limited to the foregoing description or embodiments.

Claims

1. A ribbon cable sensor assembly, comprising: a ribbon cable having corresponding pairs of conductors; at least one sensor termination region positioned on the ribbon cable, the at least one sensor termination region having insulation removed from respective individual wires of the respective pairs of conductors to provide exposed individual conductors; and A conductive material is applied to the respective exposed individual conductors in the at least one sensor termination area to form at least one sensor.

2. The ribbon cable sensor assembly according to claim 1, wherein: The at least one sensor termination area is a plurality of sensor termination areas spaced apart along the longitudinal axis of the ribbon cable, and the at least one sensor is a plurality of sensors positioned in the plurality of sensor termination areas to allow the plurality of sensors to sense different locations along the ribbon cable.

3. The ribbon cable sensor assembly of claim 1, wherein: The ribbon cable sensor assembly is positioned in a catheter.

4. The ribbon cable sensor assembly of claim 2, wherein: Each of the plurality of sensor termination areas has a conductor window having an insulation layer removed from a corresponding individual wire.

5. The ribbon cable sensor assembly of claim 4, wherein: Each conductor window is approximately 150 microns by approximately 400 microns, preferably wherein the plurality of sensors are temperature sensors monitoring the temperature in a given location along the ribbon cable sensor assembly.

6. The ribbon cable sensor assembly of claim 1, wherein: The conductive material is a conductive metal ink, preferably, wherein the silver ink has silver particles having a diameter of about 0.3 microns or less.

7. The ribbon cable sensor assembly of claim 1, wherein: The conductive material has a resistivity between about 0.03 mohm·cm and about 5 mohm·cm.

8. The ribbon cable sensor assembly of claim 1, wherein: The conductive material is diluted with about 0.5% to about 3% solvent.

9. The ribbon cable sensor assembly of claim 1, wherein: The conductive material has a thickness between about 20 microns and about 30 microns.

10. The ribbon cable sensor assembly of claim 1, wherein: The conductive material is a solidified droplet having a diameter between about 150 microns and about 400 microns.

11. The ribbon cable sensor assembly of claim 1, wherein: A non-conductive material is applied to at least one sensor termination area to cover the conductive material.

12. The ribbon cable sensor assembly of claim 11, wherein: The non-conductive material (a) is a UV curable adhesive, (b) is cured from a droplet having a diameter between about 250 microns and about 500 microns, or (c) has a thickness between about 30 microns and about 50 microns.

13. A method of manufacturing a ribbon cable sensor assembly having a plurality of sensors, the method comprising: exposing individual conductors of the ribbon cable in defined areas by removing insulation in the defined areas; applying conductive ink on the exposed individual conductors of the cable in the defined areas to form sensors; and The conductive ink is cured.

14. The method of manufacturing a ribbon cable sensor assembly according to claim 17, further comprising: applying a non-conductive material over the conductive ink; and The non-conductive material is cured.

15. The method of manufacturing a ribbon cable sensor assembly according to claim 14, wherein: The conductive ink and the non-conductive ink are applied in the form of drops by a jet dispensing printing process.

16. The method of manufacturing a ribbon cable sensor assembly according to claim 13, wherein: The insulating layer in the defined area is removed by laser ablation to form a conductive window.

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