CN110007215B

CN110007215B - Open-circuit short-circuit electrical testing method for FPC

Info

Publication number: CN110007215B
Application number: CN201910363835.6A
Authority: CN
Inventors: 王文宝
Original assignee: Xiamen Bolion Tech Co ltd
Current assignee: Xiamen Bolion Tech Co ltd
Priority date: 2019-04-30
Filing date: 2019-04-30
Publication date: 2021-05-28
Anticipated expiration: 2039-04-30
Also published as: CN110007215A

Abstract

The invention relates to the field of FPC manufacturing, and discloses an open-circuit and short-circuit electrical testing method for an FPC, which mainly comprises the following steps: (1) FPC added short circuit extension area: setting short circuit extension areas towards the outer direction of the FPC on golden fingers of the FPC, and short-circuiting different networks of the FPC in pairs in the short circuit extension areas to enable the short-circuited networks to be connected in series to form a series network; (2) open circuit testing: setting probes at the pad ends at two ends of the series network to test whether the series network is open-circuited; (3) FPC removes the short circuit extension area: after the open circuit test is qualified, slotting in a short circuit extension area of the FPC, removing the short circuit extension area or separating the short circuit extension area from the FPC, and simultaneously restoring the series network into two different networks; (4) and short circuit testing, namely arranging a probe at the pad end of the adjacent network to test whether the adjacent network has a short circuit. The electric measuring method avoids the leakage measurement of open circuit and short circuit of the FPC, avoids the waste of materials to the maximum extent, and has high reliability and low manufacturing cost.

Description

Open-circuit short-circuit electrical testing method for FPC

Technical Field

The invention relates to the field of FPC manufacturing, in particular to an open-circuit and short-circuit electrical testing method for an FPC.

Background

At present, a conventional Flexible Printed Circuit (FPC) with a golden finger requires the golden finger to perform on-off test so as to ensure the connection integrity between the golden finger and other circuits in the Circuit board. Because the design width of the golden finger of the FPC and the lead-out line thereof is generally small, generally about 0.07mm-0.15mm, the testing can not be directly carried out by using a probe, a testing pad is required to be arranged on a network connected with the golden finger to arrange the probe for testing, and the size of the testing pad is usually 0.3mm-1mm for conveniently arranging the probe.

As an example of the FPC product shown in fig. 1, there are conventionally the following two electrical measurement schemes.

Conventional electrical measurement protocol 1: as shown in fig. 2, 3 and 4, the jig is provided with a conductive adhesive 30 in the gold finger area 11 of the FPC to short the gold fingers, and at this time, a probe is provided on the pad 22 for testing to perform an open circuit test, and when the test result indicates that no open circuit is detected, it indicates that no open circuit occurs in each line. Then, the conductive adhesive 30 of the jig is removed, and a short circuit test is performed to detect whether the adjacent lines are short-circuited. However, this electrical measurement scheme has the following problems: if two gold fingers are in the same network, the conductive adhesive scheme is adopted to make the network form a loop, as shown in fig. 4, and at this time, a line in the loop is open, and the open point 23 cannot be electrically detected.

Conventional electrical measurement protocol 2: as shown in fig. 1 and 5, for the target FPC shown in fig. 1, when the FPC is designed, the gold finger end is extended outward, and the extension section 41 is provided with the test pad 42, so as to facilitate the probe arrangement for the extension section of the gold finger, thereby realizing that both ends of the circuit are provided with the test pad 42, and after the test is completed, the extension section 41 is punched out by a die so as to be separated from the final FPC product. However, in the method (1), a large number of test pads 42 need to be added, and for this reason, the gold finger needs a longer extension section 41 to reasonably distribute the test pads, which increases the waste of FPC materials and reduces the utilization rate of the materials. (2) The extension section of the golden finger is long in length, short circuit risks are increased, short circuits of the extension section of the golden finger can cause misdetection of actual products, and the yield of the products is reduced.

Therefore, those skilled in the art are devoted to developing a novel method for electrically testing open circuit and short circuit of FPC to reduce misdetection and missing detection, and to provide a product yield without significantly increasing the waste of FPC material.

Disclosure of Invention

In view of the above-mentioned defects of the prior art, an object of the present invention is to provide an electrical method for testing open circuit and short circuit of FPC, so as to reduce the false test and the missing test, and to provide the yield of products without significantly increasing the waste of FPC materials.

In order to achieve the purpose, the invention provides an open-circuit short-circuit electrical measurement method of an FPC, which comprises the following steps:

(1) FPC added short circuit extension area: setting a short circuit extension area towards the outer direction of the FPC on a golden finger of the FPC, and short-circuiting two by two different networks of the FPC in the short circuit extension area to enable the two short-circuited networks to be connected in series to form a series network;

(2) open circuit testing: setting probes at the pad ends at two ends of the series network to test whether the series network is open-circuited;

(3) FPC removes the short circuit extension area: after the open circuit test is qualified, slotting in a short circuit extension area of the FPC, separating a network of the FPC from a network of the short circuit extension area, and simultaneously restoring a series network into two different networks;

(4) and short circuit testing, namely arranging a probe at the pad end of the adjacent network to test whether the adjacent network has a short circuit.

Further, the width of the short circuit extension area is 1mm-5 mm.

Further, the diameter of the bonding pad is larger than or equal to 0.3 mm.

Compared with the conventional FPC open-circuit and short-circuit electrical testing method, the FPC open-circuit and short-circuit testing method avoids the leakage testing of the FPC open circuit and the short circuit, avoids the material waste to the maximum extent, and has high reliability and low manufacturing cost.

Drawings

Fig. 1 is an example of an FPC;

FIG. 2 is a schematic diagram of an open circuit test of the FPC of FIG. 1 using a conventional electrical testing scheme 1;

FIG. 3 is a schematic diagram of a short circuit test of the FPC of FIG. 1 using a conventional electrical testing scheme 1;

FIG. 4 is a schematic illustration of the FPC of FIG. 1 showing problems with open circuit testing using conventional electrical testing scheme 1;

FIG. 5 is a schematic diagram of an open short circuit test of the FPC of FIG. 1 using a conventional electrical testing scheme 2;

FIG. 6 is a schematic view of an open circuit test of the FPC of FIG. 1 using the electrical testing method of the present invention;

FIG. 7 is a schematic view of the FPC of FIG. 1 with the short circuit extension area removed using the electrical testing method of the present invention;

fig. 8 is a schematic diagram of a short circuit test of the FPC of fig. 1 using the electrical measuring method of the present invention.

Detailed Description

To further illustrate the various embodiments, the invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. Those skilled in the art will appreciate still other possible embodiments and advantages of the present invention with reference to these figures. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.

The invention will now be further described with reference to the accompanying drawings and detailed description.

As shown in fig. 1, 6, 7 and 8, the invention discloses an electrical method for measuring open circuit and short circuit of an FPC, taking the FPC shown in fig. 1 as an example for detection, a flexible circuit board 10 is divided into a gold finger area 11 and other areas, the flexible circuit board 10 includes a plurality of networks, for convenience of description, the network 20A and the network 20B on the FPC are designated, the network 20A and the network 20B are different networks and also adjacent networks, the network 20A is provided with a gold finger 21A in the gold finger area 11 of the flexible circuit board 10, the other areas are provided with a bonding pad 22A, the gold finger 21B of the network 20B is adjacent to the gold finger 21A of the network 20A, and the method comprises the following steps:

(1) FPC added short circuit extension area: short circuit extension areas 50 are arranged in the golden finger areas of the FPC towards the outside of the board, different networks of the FPC are short-circuited in pairs in the short circuit extension areas 50, for example, two

golden fingers

21A and 21B corresponding to

different networks

20A and 20B are led out of the board and are short-circuited in the short circuit extension areas 50, and the two

different networks

20A and 20B are connected in series to form a network as shown by a dotted line frame in FIG. 6 in the short circuit extension areas 50. For all the networks with gold fingers, the gold fingers can be led into the short circuit extension area 50 according to the distribution of the gold fingers on the FPC, and the gold fingers are connected in pairs among different networks.

(2) Open circuit testing: probes are provided at

pads

22A, 22B at either end of the series network to test whether the series network is open. Whether all series networks of the FPC are open or not is sequentially detected through the mode. As shown in fig. 6.

(3) FPC removes the short circuit extension area: after the open circuit test is passed, a groove is opened in the short circuit extension area 50 of the FPC, the short circuit extension area 50 is removed or the short circuit extension area 50 is separated from the FPC, and the series network is restored to two

different networks

20A, 20B as shown in fig. 7.

(4) And short circuit test, namely testing the adjacent networks, such as arranging probes on the

pads

22A and 22B of the

adjacent networks

20A and 20B, testing whether the

adjacent networks

20A and 20B have short circuits, and checking every two adjacent networks on the FPC according to the short circuit test, as shown in fig. 8.

The open circuit test and the short circuit test can adopt a serial test or a concurrent test. If the two probes sequentially touch the pad ends of the adjacent networks for serial testing, the probes can also be arranged by the ICT test fixture to touch all the pads of the networks to be tested one by one for concurrent testing.

For convenience of manufacturing, it is preferable that the short circuit extension region has a width of 1mm to 5mm and the pad has a diameter of 0.3mm or more.

The open-circuit short-circuit electric testing method of the FPC avoids the leakage testing of open circuit and short circuit of the FPC, avoids the waste of materials to the maximum extent, and has high reliability and low manufacturing cost.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An open-circuit short-circuit electrical measurement method of FPC is characterized in that: the original circuit of the FPC comprises a plurality of bonding pads capable of being used for arranging test probes, a plurality of golden fingers which are arranged at the top in parallel, a plurality of connecting bonding pads and connecting wires of the golden fingers, wherein the bonding pads and the golden fingers are connected by the connecting wires to form a network; the method comprises the following steps:

(1) the FPC added short circuit extension area forms the FPC lines for open circuit testing: when the FPC is produced, a short circuit extension area is arranged in the direction, facing the outside of the FPC, of the golden fingers of the FPC, connecting wires are arranged in the short circuit extension area to short the golden fingers of different networks of the FPC in pairs, the networks in the short circuit extension area are connected in series to form a series network, and the series network comprises a first connecting wire, a second connecting wire and a third connecting wire, wherein the first connecting wire is connected with a first bonding pad and the first golden finger, the second connecting wire is connected with the first golden finger and the second golden finger, and the third connecting wire is connected with the second golden finger and the second bonding pad;

(2) open circuit testing: arranging probes on a first bonding pad and a second bonding pad at two ends of a series network, and testing whether a first connecting line or a second connecting line in the series network is open or not;

(3) removing the short circuit extension area from the FPC, and recovering the original circuit of the FPC: after the open circuit test is qualified, slotting in a short circuit extension area of the FPC, removing the short circuit extension area or separating the short circuit extension area from the FPC, namely, opening a circuit of the second connecting line, and restoring the series network into two different networks, namely a first network comprising a first bonding pad, a first golden finger and a first connecting line, and a second network comprising a second golden finger, a second bonding pad and a second connecting line;

(4) and short circuit testing, namely arranging a probe on a pad of an adjacent network and testing whether the adjacent network has a short circuit.

2. An electrical open-short circuit testing method of FPC as claimed in claim 1, characterized in that: the width of the short circuit extension area is 1mm-5 mm.

3. An electrical open-short circuit testing method of FPC as claimed in claim 1, characterized in that: the diameter of the bonding pad is larger than or equal to 0.3 mm.