JP2003508929A - Flex circuit with repairable connector tail - Google Patents

Abstract

(57) Abstract: A repairable flex circuit (1) comprising a generally flexible electrically insulating substrate (2) having a first edge (3) and a plurality of arrays disposed on the substrate. Conductive circuit traces (5). Each circuit trace has an end terminating at a first connector element (8) proximate the first edge (3) and at least one second connector element spaced from the first connector element. (13), wherein the first and second connector elements are plated through holes, plated blind vias, or solder pads.

Description

Detailed Description of the Invention

TECHNICAL FIELD The present invention relates generally to flexible printed circuits (“flex circuits”),
In particular, it relates to approaches for repairing flex circuits.

BACKGROUND OF THE INVENTION FIG. 1 shows a typical application of a flex circuit, where the connector tail portion of the flex circuit 987 is an electronic assembly 34 (which is an electronic module) to which it is desired to connect. ), A circuit board, another flex circuit, an electrical connector, or some other electrical / electronic device, component, or assembly. (Although not shown, the flex circuit itself can occupy the same place as the electronic components, or it can be part of an electrical wiring / bus system, etc.). The connection between flex circuit 987 and electronic assembly 34 is Most typically by soldering.

Particularly in the computer, automotive, aviation, and space industries, the use of flex circuits rather than the usual single wire harness has become increasingly common.
However, one disadvantage of using flex circuits is that the flex-connected electronic assembly 34 is difficult to service. For example, if a particular assembly 34 fails and needs to be replaced, the assembly 34 may be assembled without damaging the flex circuit or without the tedious, tedious and costly procedure of performing the replacement. It is difficult to disconnect from the circuit and reconnect the replacement assembly. Therefore, it is desirable to provide a technique that allows the use of flex circuits, while at the same time providing an easy, effective, and inexpensive technique that allows replacement of a failed electronic assembly 34.

SUMMARY OF THE INVENTION The present invention overcomes the deficiencies of prior art approaches by providing a flex circuit having a repairable connector tail portion. The article according to the invention is
A generally flexible electrically insulating substrate having a first edge and a plurality of conductive circuit traces arranged on the substrate. Each circuit trace has an end terminating in a first connector element proximate the first edge and at least one second connector element spaced from the first connector element. However, each of the first and second connector elements is a plated through hole, a plated blind via, or a solder pad.

The objects and advantages of the present invention include (1) connection of the flex circuit to an electronic module, another flex circuit, etc., and (2) disconnection and reconnection of the flex circuit necessary to facilitate repair. Providing a connector portion for a flex circuit that facilitates both.

Another object and advantage is to facilitate the incorporation of the present invention within the design of most existing flex circuits.

These and other advantages, features and objects of the present invention will become apparent from the detailed description given below with reference to the accompanying drawings.

Embodiments Reference will be made to the attached drawings. 2-8 show a repairable flex circuit 1 according to the present invention.
Is shown. The flex circuit 1 comprises a generally flexible electrically insulating substrate 2 having a first edge 3 and a plurality of conductive circuit traces 5 arranged on the substrate. Each circuit trace has at least one second connector element 13 having an end terminating at the first connector element 8 proximate to the first edge 3 and spaced from the first connector element. And each of the first and second connector elements is a plated through hole, a plated blind via, or a solder pad.

To facilitate an understanding of the present invention, all reference numbers used along with the elements they represent are summarized in the following table. 1 = repairable flex circuit / connector tail 1 ′ = replacement flex circuit / connector tail 2 = connector tail base 3 = first edge of connector tail 5 = circuit trace on / in connector tail 8 = First connector element 13 = Second connector element 21 = Cutting line between the first and second connector elements 34 = Electronic assembly connected to connector tail 55 = Electronic assembly connector element 89 = Overlapping Mechanical / electrical connection area 144 = straight alignment line of the connector element 233 = zigzag alignment line of the connector element 377 = newly cut (next) first edge 610 = alternative cut line 987 = Prior art flex circuit / connector tail '= Replacement part (denoted by "prime" mark) A = Flex / tail connector element segment B = no flex / tail connector segment

The first and second connector elements 8/13 of the flex circuit connector tail 1 are
Exposed for easy interconnection with pins of the electronic assembly 34 to which the connector tail 1 is connected, plated through holes, solder pads, or other connector features 55 (ie, flex circuit isolation). Should not be covered by the polymer layer). Connector tail 1 and assembly 3
The interconnections with 4 are preferably made by soldering, but ultrasonic welding,
It can also be performed by heat staking, crimping, pinning, laser bonding and the like. Regardless of the processing method selected, the interconnection is such that connector element 55 of assembly 34 is the first of the connector tails, as indicated at 89 in FIG.
The flex tail 1 and the electronic assembly 34 are aligned so that they overlap the connector element 8 of FIG. This alignment of the connector tail 1 and the respective connector element 8/55 of the electronic assembly 34 results in an overlapping element 8/5.
5 can be connected to each other. Connector element 8/55 using soldering
If is a plated through hole, it may be desirable to insert pins through each pair of overlapping through holes prior to soldering to aid in alignment and strengthening the solder bond.

The connector elements 8/13 can be arranged over the connector tail 1 in a variety of ways, but they are preferably distributed generally evenly along the length of each circuit trace 5. It is also preferred that each trace 5 be terminated at the first connector element 8 proximate to the first edge 3 before any repair (described below). Furthermore, it should be understood that the connector elements 8/13 on the connector tail 1 should be arranged to match and mate with the connector element 55 of the electronic assembly 34. In other words, the pattern and spacing of connector elements 8/13 in the connector tail should essentially be a mirror of the pattern and spacing of connector elements 55 in the corresponding assembly. This is desirable so that the overlapping connector elements can be properly aligned. For example, each of the first and second connector elements 8/13 may be (1) along a generally straight line 144 running across the length of the trace 5 (see FIG. 8) or (2) across the trace. Along generally running zigzag line 233 (see FIGS. 2-7), it can be aligned with all corresponding other ones of the first and second connector elements.

When the respective connector elements of the flex circuit 1 and the electronic assembly 34 are aligned and connected as described above, the connector tail 1 of the present invention electrically connects the trace 5 of the flex circuit to the corresponding trace of the electronic assembly. And mechanically.

If at a later time it becomes necessary to disconnect either the flex circuit 1 or the electronic assembly 34 (eg, because a component associated with one circuit has failed), the connector tail 1 will be replaced by a new flex circuit 1 ′. Alternatively, it can be cut to provide a second set of connector elements 13 to which the electronic assembly 34 'can be connected. The replacement process is shown in FIGS. 4-5, which show the assembly 34 being replaced. The replacement process is carried out as shown in FIG. 4, in which the connector tail is along a cutting line 21 running transversely to the trace 5 between the first connector element 5 and a second set of second connector elements 13 adjacent thereto. Start by cutting 1. This essentially makes these second connector elements 13 the connector elements closest to the newly cut first edge 377. As a result, as shown in FIG.
The connector element 55 'of the replacement assembly 34' has the newly cut first edge 37
The connector tail 1 and the replacement assembly 34 'can be aligned such that they overlap the second connector element 13 of the connector tail close to 7 (or the connector element 13 overlaps the connector element 55').

Alternatively, rather than disconnecting the original electronic assembly 34 and replacing it with a new assembly 34 ′ as shown in FIGS. 4-5, replace the original flex circuit 1 as shown in FIGS. 6-7. It is also possible to replace it with a new flex circuit 1 '. In this case, instead of cutting along the cutting line 21, the cutting line 61
Cutting along 0 facilitates replacement. After making this cut, the connector element segment ("A") with the smaller connector tail is removed from the electronic assembly 34.
Still attached to the main connector-less tail segment (“B”)
Can be discarded. Cutting along the cutting line 610, as described above and shown in FIG. 7, allows a new connector tail 1'to be attached to a newly cut edge to contact a set of second connector elements. 13 is obtained.

As will be appreciated from the above description, the specifically constructed connector tail of the present invention is not only used initially to interconnect the flex circuit 1 and the electronic assembly 34, but Advantageously flex circuit 1 or assembly 3
It is also possible to remove 4 from the integrated circuit connection and use it to easily replace it with a new flex circuit 1 '/ assembly 34'. If the connector tail 1 is provided with only one set of second connector elements 13, repair / replacement after initial connection can be performed only once. However, if more than one set of second connector elements 13 is provided, the same number of repairs can be performed. The number of sets of second connector elements 13 provided should be determined according to how often the circuit is expected to be repaired.

Those skilled in the art will be able to make various other modifications of the present invention. For example, in the above embodiment, only two circuits (for example, 1 and 34) are connected at a given time, but as shown in FIG. 8, the present invention actually uses two circuits at a time. It can be used to connect many circuits together. The flex circuit of the present invention also has a conventional flex circuit structure (ie, the substrate 2 is made of polyester, polyimide, polyetherimide, etc., and the circuit trace 5 is made of copper, carbon, aluminum, solder, conductive ink, etc. It should be noted that the area surrounding the electronic assembly 34 or its connector element 55 need not be made flexible. In fact, the present invention is equally applicable to electronic assemblies 34 made of rigid FR-4 epoxy / glass, ceramic (eg, alumina), etched tri-layer metal structures, and so on. Further, although the term "connector tail" has been used to describe the specifically designed connector element array of the present invention, the array of connector elements 8/13 does not necessarily extend outward from the perimeter of the flex circuit. There is no need to put it in the "tail" part. That is, the term "tail" is used to mean the portion of the flex circuit in which the first and second connector elements 8/13 are arrayed in accordance with the present invention, the geometrical shape of this portion itself. There is no intention to limit or restrict the shape. It should be understood that other modifications not explicitly stated above are possible and within the scope of the invention. The claims limit the scope of the invention.

[Brief description of drawings]

FIG. 1 is a plan view of both prior art flex circuits prior to connection to an electronic assembly.

FIG. 2 is a plan view of the flex circuit connector tail of the present invention prior to connecting with the electronic assembly.

FIG. 3 is a plan view of a flex circuit connector tail of the present invention after connecting with an electronic assembly.

4 is a plan view of the circuit connection of FIG. 3 after cutting along the cutting line and before replacing the electronic assembly.

5 is a plan view of the circuit connection of FIG. 3 after cutting along the section line and after replacing the electronic assembly.

6 is a plan view of the circuit connection of FIG. 3 after cutting along the alternate cut line and before replacing the electronic assembly.

7 is a plan view of the circuit connections of FIG. 3 after cutting along the alternate cut line and after replacing the electronic assembly.

[Figure 8]   FIG. 8 is a plan view of an alternative embodiment of the present invention.

─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Atari Atatura             48188 Ki, Michigan, United States             Chang Thong Danbury Road 44821 (72) Inventor Nation Brenda Joyce             48098, Michigan, United States             Roy Tall Oaks Drive 2404 (72) Inventor Trabrowski John             48083, Michigan, United States             Roy Highland 3949 F term (reference) 5E317 AA07 AA24 BB03 BB11 BB12                       CC31 GG17                 5E344 AA02 AA22 BB02 BB04 CC24                       DD02 EE30

Claims (16)

[Claims] 1. A repairable flex circuit having a first edge, a generally flexible electrically insulative substrate, and a plurality of conductive circuit traces arranged on the substrate. And each circuit trace terminates in a first connector element proximate the first edge, and each circuit trace is at least one second connector element spaced from the first connector element. A repairable flex circuit, wherein each of the first and second connector elements is a plated through hole, a plated blind via, or a solder pad. 2. The first and second connector elements of each circuit trace include:
2. A substantially even distribution along the circuit traces.
Repairable flex circuit as described in. 3. The repairable flex circuit of claim 1, wherein the circuit traces run substantially parallel to each other. 4. The first and second connector elements are all of the first and second connector elements along a generally straight line that runs laterally to the length of the circuit trace. The repairable flex circuit of claim 1, wherein the repairable flex circuit is aligned with the other corresponding one of the. 5. The first and second connector elements are all of the first and second connector elements along a generally zigzag line that runs laterally to the length of the circuit trace. The repairable flex circuit of claim 1, wherein the repairable flex circuit is aligned with the other corresponding one of the. 6. The substrate is made of polyester, polyimide, or polyetherimide, and the circuit traces are made of copper, carbon, aluminum, solder, or conductive ink. The repairable flex circuit described in 1. 7. A repairable flex circuit having a first edge, a generally flexible electrically insulative substrate, and a plurality of conductive circuit traces arranged on the substrate. And each circuit trace terminates at a first connector element proximate to the first edge and is spaced from the first connector element by at least one.
Two second connector elements, each of the first and second connector elements being a plated through hole, a plated blind via, or a solder pad, wherein the first and second connector elements are each Aligned along a generally zig-zag line running transverse to the length of the circuit traces with respect to the corresponding other of all of the first and second connector elements, A repairable flex circuit. 8. The first and second connector elements of each circuit trace include:
8. A substantially even distribution along the circuit traces.
Repairable flex circuit as described in. 9. The repairable flex circuit of claim 7, wherein the circuit traces run substantially parallel to each other. 10. The substrate is made of polyester, polyimide, or polyetherimide, and the circuit traces are copper, carbon, aluminum, solder,
Alternatively, the repairable flex circuit of claim 7, wherein the repairable flex circuit is made of conductive ink. 11. A method of repairing an electrical circuit, comprising the step of providing an electrical assembly, the electrical assembly including a flex circuit having a connector tail portion,
The connector tail portion has a first edge and a plurality of circuit traces arranged on or within the flex circuit, each circuit trace proximate the first edge. At least one second connector element terminating in the first connector element and spaced from the first connector element, each of the first and second connector elements being plated through A hole, a plated blind via, or a solder pad, further comprising a first electrical component having a second edge and a plurality of circuit traces terminating immediately adjacent the second edge, The connector tail portion and the first electrical component are connected to their respective first
And second edges are arranged in contact with one another and overlap, wherein the connector tail portion and the respective circuit traces of the first electrical component are mechanically interlocked with each other in each of the first connector elements. And electrically connected, the method further includes cutting the connector tail portion across the connector tail portion between the first connector element and the second connector element, thereby providing the first connector element. Disconnecting one electrical component and the attached first connector element from the connector tail portion and the second connector element, thereby forming a third edge of the connector tail portion in the immediate vicinity of the second connector element. And a second electrical component such that the fourth edge of the second electrical component contacts and overlaps the third edge of the connector tail portion. Arranging the second electrical component and the respective circuit traces of the connector tail portion substantially mechanically and electrically relative to each other in the second connector element. And a step of physically connecting. 12. The first and second connector elements include first and second connector elements along a generally straight line running transversely to the length of the circuit traces on the connector tail portion. The method according to claim 11, characterized in that it is aligned with all corresponding other ones of the two connector elements. 13. Each of the first and second connector elements includes the first and first connector elements along a generally zigzag line that runs transverse to the length of the circuit traces on the connector tail portion. The method according to claim 11, characterized in that it is aligned with all corresponding other ones of the two connector elements. 14. A method of repairing an electrical circuit, comprising the step of providing an electrical assembly, the electrical assembly including a flex circuit having a connector tail portion,
The connector tail portion has a first edge and a plurality of circuit traces arranged on or within the flex circuit, each circuit trace proximate the first edge. Including at least one second connector element terminating in the first connector element and spaced from the first connector element, wherein each of the first and second connector elements is a plated through hole A plated blind via, or a solder pad, the connector tail portion including a connector element segment supporting the first and second connector elements and a non-connector segment contacting the connector element segment, The electrical assembly further includes an electrical component having a second edge and a plurality of turns terminating immediately adjacent the second edge. A path trace, the connector tail portion and the electrical component are arranged such that their respective first and second edges are in contact with and overlap each other, and the connector tail portion and the electrical component The respective circuit traces are mechanically and electrically connected to each other at each of the first connector elements and the method further comprises traversing the connector tail portion in the immediate vicinity of the second connector element. Cutting the connector tail portion to disconnect the no-connector segment from the connector element segment and the attached electrical component, thereby forming a third edge of the connector element segment proximate to the second connector element. And preparing a second flex circuit having a plurality of circuit traces, Each said circuit trace has at least one set of third connector elements, each of said at least one set of third connector elements being arranged in contact with said second connector element. Further arranging the second flex circuit such that the fourth edge of the second flex circuit contacts and overlaps the third connector element; and the second flex circuit and the connector element. Mechanically and electrically connecting each circuit trace of the segment to each other at the second connector element. 15. Each of the first and second connector elements includes the first and second connector elements along a generally straight line that runs transversely to the length of the circuit trace on the connector tail portion. The method according to claim 14, characterized in that it is aligned with all corresponding other ones of the two connector elements. 16. Each of said first and second connector elements comprises said first and first connector elements along a generally zigzag line running transverse to the length of said circuit traces on said connector tail portion. The method according to claim 14, characterized in that it is aligned with all corresponding other ones of the two connector elements.