Detection Method for Poor Stamping of Gold Fingers on Flexible Printed Circuit Boards

Abstract

The present invention discloses a method for detecting poor punching of gold fingers on a flexible printed circuit board, which includes providing an original flexible printed circuit board provided with a gold finger punching area and a punching detection mark making area; making gold fingers on the gold finger punching area of the original flexible printed circuit board, and at the same time making punching detection marks on the punching detection mark making area to obtain a circuit board to be punched; according to a preset punching design, performing gold finger profile punching on the gold finger punching area of the circuit board to be punched; at the same time, according to the preset punching design, performing punching on the punching detection marks to obtain a target flexible printed circuit board; performing electrical testing on the target flexible printed circuit board, and at the same time performing electrical testing on the punched punching detection marks, and obtaining the gold finger punching result according to the electrical testing result of the punching detection marks. The present invention makes punching detection marks simultaneously in the conventional process of gold fingers, improving the inspection efficiency; using the punching detection marks to detect poor punching of gold fingers, improving the detection rate of defective products.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible printed circuit board manufacturing, and particularly relates to a method for detecting poor stamping of gold fingers on a flexible printed circuit board. Background Art

[0002] In the field of flexible printed circuit board (FPC) manufacturing, some FPC products have gold finger designs. When manufacturing gold fingers, a mold is required to stamp and form the outer shape of the gold finger position (referred to as gold finger outer shape stamping). The tolerance of the gold finger outer shape is relatively strict, generally requiring a deviation of no more than 0.05 mm. Exceeding this threshold range will affect the quality of the entire FPC product.

[0003] However, in the actual operation process, there will inevitably be stamping defects such as stamping offset (i.e., the stamping deviation exceeds the threshold range) and missing stamping. In the case of poor stamping, it is difficult for inspectors to directly identify through visual inspection, and it is impossible to effectively detect the situation of poor stamping, resulting in a certain risk of omission. If a measuring tool is used to measure the stamping deviation, it is necessary to measure each single product one by one, and the detection efficiency is too low to achieve batch detection, thus unable to meet the needs of mass production. At the same time, using a measuring tool cannot directly detect the missing stamping defect, and it is impossible to completely screen out the defective products with poor gold finger stamping, resulting in the yield of FPC products still unable to be improved. Summary of the Invention

[0004] In view of this, the present invention provides a method for detecting poor stamping of gold fingers on a flexible printed circuit board to solve the problems of low detection efficiency and difficulty in completely detecting defective products with poor stamping in the prior art.

[0005] The present invention provides a method for detecting poor stamping of gold fingers on a flexible printed circuit board, including:

[0006] Providing an original flexible printed circuit board provided with a gold finger stamping area and a stamping detection mark making area;

[0007] Making gold fingers on the gold finger stamping area of the original flexible printed circuit board, and at the same time making stamping detection marks on the stamping detection mark making area to obtain a circuit board to be stamped;

[0008] According to a preset stamping design, performing gold finger outer shape stamping on the gold finger stamping area of the circuit board to be stamped; at the same time, according to the preset stamping design, performing stamping on the stamping detection marks to obtain a target flexible printed circuit board;

[0009] Perform electrical testing on the target flexible printed circuit board, and at the same time perform electrical testing on the punching detection mark. Obtain the punching result of the gold finger according to the electrical testing result of the punching detection mark.

[0010] Optionally, the punching detection mark manufacturing area is located on the waste area near the gold finger punching area on the original flexible printed circuit board, and the gold finger manufactured on the gold finger punching area and the punching detection mark manufactured on the punching detection mark manufacturing area are located on the same side of the circuit board to be punched.

[0011] Optionally, manufacturing the gold finger on the gold finger punching area of the original flexible printed circuit board and manufacturing the punching detection mark on the punching detection mark manufacturing area at the same time to obtain the circuit board to be punched includes:

[0012] Adopt an etching process to etch the gold finger on the gold finger punching area of the original flexible printed circuit board according to the preset gold finger design; at the same time, etch the punching detection mark on the punching detection mark manufacturing area of the original flexible printed circuit board according to the preset mark design to obtain the circuit board to be punched.

[0013] Optionally, the punching detection mark includes a first copper interface, a second copper interface, a third copper interface, a fourth copper interface, a first circuit, a second circuit, and a third circuit;

[0014] The first copper interface is connected to the fourth copper interface through the first circuit, the second copper interface is connected to the fourth copper interface through the second circuit, and the third copper interface is connected to the fourth copper interface through the third circuit;

[0015] Wherein, the first circuit, the second circuit, and the third circuit are not connected to each other, and the first circuit, the second circuit, and the third circuit are spaced apart according to a preset etching spacing; the connection points between the first circuit and the fourth copper interface and between the third circuit and the fourth copper interface are both located at the edge of the fourth copper interface, and the connection point between the second circuit and the fourth copper interface is close to the center of the fourth copper interface.

[0016] Optionally, the preset punching design includes the minimum spacing of the die cutting edge and the punching spacing between the edge of the gold finger and the outer shape of the gold finger.

[0017] Optionally, performing punching on the punching detection mark according to the preset punching design includes:

[0018] Perform punching on the fourth copper interface on the punching detection mark to form a through hole in the fourth copper interface, so that the first copper interface is connected to the remaining part of the fourth copper interface through the first line, and the third copper interface is connected to the remaining part of the fourth copper interface through the third line, and the second copper interface is also connected to the through hole through the second line;

[0019] Wherein, the distance between the edge of the through hole and the edge of the fourth copper interface is less than or equal to the punching distance, and the distance between the edge of the fourth copper interface and the shape of the gold finger is greater than or equal to the minimum distance of the die cutting edge.

[0020] Optionally, the electrical test results include a first test result between the first copper interface and the third copper interface, a second test result between the second copper interface and the first copper interface, and a third test result between the second copper interface and the third copper interface;

[0021] Performing an electrical test on the punched punching detection mark, and obtaining the gold finger punching result according to the electrical test result of the punching detection mark, including:

[0022] Connect a first test pin to the first copper interface, two second test pins to the second copper interface, and a third test pin to the third copper interface. Perform an electrical test on the punching detection mark according to the first test pin, the two second test pins and the third test pin to obtain the first test result, the second test result and the third test result respectively;

[0023] If the first test result is an open circuit, it is determined that the gold finger punching result is that the gold finger has a punching offset;

[0024] If the first test result is conductive, and both the second test result and the third test result are open circuits, it is determined that the gold finger punching result is that the gold finger punching is normal;

[0025] If the first test result is conductive, and both the second test result and the third test result are short circuits, it is determined that the gold finger punching result is that the gold finger has a missed punch.

[0026] Optionally, before performing the gold finger shape punching on the gold finger punching area of the circuit board to be punched according to the preset punching design, it further includes:

[0027] Apply a protective film to all areas of the circuit board to be punched except the gold finger punching area, the first copper interface, the second copper interface and the third copper interface.

[0028] Optionally, the distances between the protective film and the edges of the first copper interface, the distances between the protective film and the edges of the second copper interface, and the distances between the protective film and the edges of the third copper interface are all greater than a preset fitting tolerance; and / or, the distance between the protective film and the shape of the gold finger is greater than the preset fitting tolerance.

[0029] Optionally, the number of the original flexible printed circuit boards is one or more.

[0030] Advantages of the present invention: By providing a punching detection mark manufacturing area on the original flexible printed circuit board, along with the normal manufacturing process of the gold fingers in the gold finger punching area, punching detection marks are simultaneously manufactured on this punching detection mark manufacturing area, facilitating subsequent detection of the punching situation of the gold fingers; punching the shape of the gold fingers in the gold finger punching area according to a preset punching design to achieve the gold finger punching in the normal manufacturing process; based on the same preset punching design, punching on the punching detection marks, and the punching of the gold fingers can be simulated through these punching detection marks; finally, during the normal manufacturing process of electrical testing the obtained target flexible printed circuit board, the punching detection marks are simultaneously electrically tested, and the true situation of the simulated gold finger punching is analyzed according to the electrical test results of the punching detection marks, realizing the detection of defective gold finger punching.

[0031] The method for detecting defective gold finger punching on the flexible printed circuit board of the present invention, by simultaneously manufacturing, punching, and electrically testing the punching detection marks during the normal manufacturing processes of gold finger manufacturing, punching, and electrical testing, does not require an additional manufacturing process for the punching detection marks, and simultaneously improves the production efficiency and inspection efficiency; using the punching of the punching detection marks to simulate the gold finger punching process, and the electrical testing based on these punching detection marks can effectively control the products with defective gold finger punching, overcoming the problem of the risk of omission caused by the difficulty in detecting defective punching during gold finger punching. At the same time, using electrical testing instead of measuring tools not only improves the production efficiency but also effectively improves the detection rate of defective products, and can control 100% of the defective gold finger punching. Description of the Drawings

[0032] The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings. The drawings are schematic and should not be construed as any limitation to the present invention. In the drawings:

[0033] Figure 1 Shows a flowchart of a method for detecting defective gold finger punching on a flexible printed circuit board in an embodiment of the present invention;

[0034] Figure 2 Shows a top view structure diagram of a punching detection mark in an embodiment of the present invention;

[0035] Figure 3The top view structure diagram of the punching detection mark after punching by S3 in the embodiment of the present invention is shown;

[0036] Figure 4 The top view structure diagram of the gold finger and the outer shape of the gold finger on the target flexible printed circuit board obtained after punching by S3 in the embodiment of the present invention is shown;

[0037] Figure 5A The top view model structure diagram of the punching detection mark in the case of punching offset of the gold finger in the embodiment of the present invention is shown;

[0038] Figure 5B The top view model structure diagram of the punching detection mark in the case of normal punching of the gold finger in the embodiment of the present invention is shown;

[0039] Figure 5C The top view model structure diagram of the punching detection mark in the case of missing punching of the gold finger in the embodiment of the present invention is shown;

[0040] Figure 6A The layout schematic diagram of the first implementation manner of making punching detection marks on multiple original flexible printed circuit boards in the embodiment of the present invention is shown;

[0041] Figure 6B The layout schematic diagram of the second implementation manner of making punching detection marks on multiple original flexible printed circuit boards in the embodiment of the present invention is shown;

[0042] Figure 6C The layout schematic diagram of the third implementation manner of making punching detection marks on multiple original flexible printed circuit boards in the embodiment of the present invention is shown.

[0043] Explanation of reference numerals:

[0044] 1. Punching detection mark, 2. Gold finger, 3. Outer shape of gold finger, 4. Original flexible printed circuit board, 11. First copper interface, 12. Second copper interface, 13. Third copper interface, 14. Fourth copper interface, 15. First circuit, 16. Second circuit, 17. Third circuit. Detailed implementation manners

[0045] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0046] Embodiment

[0047] A method for detecting poor stamping of gold fingers on a flexible printed circuit board, as Figure 1 shown, includes the following steps:

[0048] S1, Provide an original flexible printed circuit board provided with a gold finger stamping area and a stamping detection mark making area.

[0049] Specifically, the original flexible printed circuit board is a single-sided board, a double-sided board or a multi-layer board, usually a double-sided board or a multi-layer board.

[0050] The single-sided board is specifically a single-sided copper-clad substrate composed of a layer of copper foil and an insulating substrate; the double-sided board is specifically a double-sided copper-clad substrate composed of double-layer copper foil and an insulating substrate, and the double-layer copper foil is respectively located on both sides of the insulating substrate; the multi-layer board is a substrate containing multiple layers of copper foil, and is laminated by a double-sided board and several single-sided boards.

[0051] Preferably, the stamping detection mark making area is located on the waste area near the gold finger stamping area on the original flexible printed circuit board, and the gold finger made on the gold finger stamping area and the stamping detection mark made on the stamping detection mark making area are located on the same side of the circuit board to be stamped.

[0052] There is usually an area for laying out the core circuit on the original flexible printed circuit board, which is called the circuit area or the effective area, and the rest of the area is called the waste area; the gold finger is a part of the core circuit of the original flexible printed circuit board, so the gold finger stamping area for making the gold finger is located in the effective area of the original flexible printed circuit board. In this embodiment, the stamping detection mark making area for making the stamping detection mark is arranged on the waste area near the gold finger stamping area, and the stamping detection mark is a component for detecting poor stamping of the gold finger. Therefore, the waste on the original flexible printed circuit board can be fully utilized to achieve the purpose of detecting poor stamping of the gold finger, without the need to additionally provide materials for making the stamping detection mark, and it is also convenient to make the stamping detection mark simultaneously with the conventional processes of gold finger making, stamping and electrical testing. Placing the gold finger and the stamping detection mark on the same side of the circuit board can ensure the reliability of the stamping detection mark for detecting the stamping situation of the gold finger. Among them, the distance between the stamping detection mark and the gold finger needs to be determined according to the layout space.

[0053] As Figure 1 shown, S2, Make a gold finger on the gold finger stamping area of the original flexible printed circuit board, and at the same time make a stamping detection mark on the stamping detection mark making area to obtain a circuit board to be stamped.

[0054] Preferably, S2 includes:

[0055] Using an etching process, according to a preset gold finger design, etch the gold finger on the gold finger punching area of the original flexible circuit board; at the same time, according to a preset mark design, etch the punching detection mark on the punching detection mark making area of the original flexible circuit board to obtain the circuit board to be punched.

[0056] During the process of etching the gold finger as described above, etching the punching detection mark at the same time improves the detection efficiency on the one hand and facilitates the subsequent electrical measurement of the punching detection mark based on the copper foil on the original flexible circuit board on the other hand; among them, the preset gold finger design refers to the relevant parameters of the gold finger preset before manufacturing the flexible board product, such as the circuit layout of the gold finger, the size of the gold finger, etc. Based on the above preset gold finger design, it is convenient to manufacture a gold finger that meets the requirements of the flexible board circuit and ensure the functionality of the flexible board product; the preset mark design defines the parameter requirements of the punching detection mark, including the positions, sizes, etc. of the components in the mark. Based on the above preset mark design, it is convenient to manufacture a punching detection mark that meets the mark parameter requirements, thereby ensuring the realization of the detection of defective gold finger punching. Among them, since the punching detection mark is etched from the waste material near the gold finger punching area and its material is copper, a circuit network for detecting defective gold finger punching through electrical measurement can be obtained subsequently, realizing the detection of defective gold finger punching.

[0057] Preferably, as Figure 2 shown, the punching detection mark 1 includes a first copper interface 11, a second copper interface 12, a third copper interface 13, a fourth copper interface 14, a first line 15, a second line 16, and a third line 17;

[0058] The first copper interface 11 is connected to the fourth copper interface 14 through the first line 15, the second copper interface 12 is connected to the fourth copper interface 14 through the second line 16, and the third copper interface 13 is connected to the fourth copper interface 14 through the third line 17;

[0059] Among them, the first line 15, the second line 16, and the third line 17 are not connected to each other, and the first line 15, the second line 16, and the third line 17 are all spaced apart according to a preset etching spacing; the connection points between the first line 15 and the fourth copper interface 14 and the connection points between the third line 17 and the fourth copper interface 14 are both located at the edge of the fourth copper interface 14, and the connection point between the second line 16 and the fourth copper interface 14 is close to the center of the fourth copper interface 14.

[0060] Since the gold fingers are prone to two types of defects during punching, namely punching deviation and missed punching, in this embodiment, the above-mentioned first copper interface is connected to the fourth copper interface through the first line, the second copper interface is connected to the fourth copper interface through the second line, and the third copper interface is connected to the fourth copper interface through the third line, forming a line network with three branches. Based on this line network, it is convenient to obtain corresponding test results during subsequent electrical testing by accessing test pins at the first copper interface, the second copper interface, and the third copper interface respectively, and then accurately analyze and judge different punching defects during the gold finger punching process according to these test results. Among them, the first line, the second line, and the third line are not connected to each other, and the three lines are also spaced apart according to a preset etching spacing, which can ensure that the three branches in this line network of punching detection marks do not interfere with each other. Combining the connection points between the first line and the fourth copper interface (referred to as the first connection point), the connection points between the third line and the fourth copper interface (referred to as the third connection point) are both located at the edge of the fourth copper interface, and the connection point between the second line and the fourth copper interface (referred to as the second connection point) is close to the center of the fourth copper interface. The setting of these connection points can facilitate the subsequent simulation of the gold finger punching process through the punching of the punching detection mark, so that the second copper interface is connected to the through hole formed by punching, while the first copper interface and the third copper interface are still connected to the remaining part of the fourth copper interface, and then the second copper interface is isolated from both the first copper interface and the third copper interface, which is convenient for accurately determining whether there are defects in the gold finger punching process simulated by the punching detection mark based on these three different copper interfaces, namely the first copper interface, the second copper interface, and the third copper interface.

[0061] Preferably, the shapes of the first copper interface 11, the second copper interface 12, and the third copper interface 13 are all circular.

[0062] Preferably, the shape of the fourth copper interface 14 is circular or rectangular.

[0063] With the copper interfaces of the above regular shapes, it is convenient to access the test pins better during subsequent electrical testing, realize good conduction between each copper interface and the test pins, and ensure the smooth progress of electrical testing; it can also achieve a compact layout in the waste area without occupying too much space.

[0064] Specifically, in this embodiment, the shape of the fourth copper interface 14 is rectangular.

[0065] Since it is necessary to simulate the gold finger punching process by punching on the fourth copper interface later, punching on the rectangular fourth copper interface can better measure the distance between the through hole formed by punching and the edge of the fourth copper interface, and then ensure that the through hole formed by punching is consistent with the gold finger punching process, ensuring the reliability of the simulated punching process.

[0066] In this embodiment, the first copper interface, the second copper interface, and the third copper interface are all circular pads (or called circular pads), and the fourth copper interface is a square pad (or called square pad). The sizes and specific positions of the copper interfaces can be determined according to the layout space of the entire flexible board.

[0067] As Figure 1 shown, in S3, according to the preset punching design, perform the outer shape punching of the gold fingers on the gold finger punching area of the circuit board to be punched; at the same time, according to the preset punching design, perform punching on the punching detection mark to obtain the target flexible circuit board.

[0068] Preferably, before S3, it further includes:

[0069] Apply a protective film to all areas of the target flexible circuit board except the gold finger punching area, the first copper interface, the second copper interface, and the third copper interface.

[0070] Since the part that needs to be exposed in the flexible board product is the gold finger, and only the first copper interface, the second copper interface, and the third copper interface need to be connected to the corresponding test pins respectively during the electrical test, and the rest do not need to be exposed. By applying the protective film, it can play a role in protecting these areas that do not need to be exposed.

[0071] Preferably, the distances between the protective film and the edges of the first copper interface, the distances between the protective film and the edges of the second copper interface, and the distances between the protective film and the edges of the third copper interface are all greater than the preset fitting tolerance; and / or, the distance between the protective film and the outer shape of the gold finger is greater than the preset fitting tolerance.

[0072] Through the limitation of the above distances, a part of the space can be reserved for the exposed areas, avoiding the influence of the protective film and the overflow glue generated during the application of the protective film on the gold fingers, the first copper interface, the second copper interface, and the third copper interface, and ensuring the functionality of the flexible board product and the electrical test performance of the first copper interface, the second copper interface, and the third copper interface.

[0073] Preferably, the preset punching design in S3 includes the minimum distance between the die cutting edges and the punching distance between the edge of the gold finger and the outer shape of the gold finger.

[0074] Since punching requires a punching die, and the cutting edge of the punching die has a certain size, when punching, punching according to the minimum distance between the cutting edge of the die and the target (i.e., the minimum die cutting edge distance) can reserve a certain operating space for the cutting edge of the die, avoiding the inability to punch or punching fracture due to too small space, and ensuring the normal realization of the punching of the gold finger and the punching of the punching detection mark; when punching the gold finger, since the gold finger is a part of the core circuit, by limiting the punching distance between the edge of the gold finger and the outer shape of the gold finger, more specifically, this punching distance refers to the minimum distance between the edge of the gold finger and the outer shape of the gold finger, it can better protect the gold finger, avoid damage to the gold finger caused by poor punching, and affect the functionality of the flexible board product; at the same time, when punching the punching detection mark, according to the punching distance between the edge of the gold finger and the outer shape of the gold finger, the punching in the punching detection mark can be a true simulation of the gold finger punching, improving the reliability of obtaining the gold finger punching result through electrical testing subsequently.

[0075] Preferably, in S3, according to the preset punching design, punching on the punching detection mark includes:

[0076] Punching the fourth copper interface on the punching detection mark to form a through hole in the fourth copper interface, so that the first copper interface is connected to the remaining part of the fourth copper interface through the first line, and the third copper interface is connected to the remaining part of the fourth copper interface through the third line, and also making the second copper interface connected to the through hole through the second line;

[0077] Wherein, the distance between the edge of the through hole and the edge of the fourth copper interface is less than or equal to the punching distance, and the distance between the edge of the fourth copper interface and the outer shape of the gold finger is greater than or equal to the minimum die cutting edge distance.

[0078] During the punching process of the above punching detection mark, since the second connection point connected to the second circuit is close to the center of the fourth copper interface, when a through hole is punched in the fourth copper interface, the second connection point can be punched off, so that the second circuit is connected to the through hole instead of the remaining part (made of copper) of the fourth copper interface; while the first connection point and the third connection point are both located at the edge of the fourth copper interface, and the punching is carried out inside the fourth copper interface, so the first connection point and the third connection point remain after punching, so that the first circuit and the third circuit are still connected to the remaining part (made of copper) of the fourth copper interface. On the one hand, the simulation of the gold finger punching is realized, and on the other hand, it is convenient to perform electrical testing based on these two different types of copper interfaces (the first type is the second copper interface having a connection relationship with the through hole, and the second type is the first copper interface and the third copper interface having a connection relationship with the remaining part of the fourth copper interface). Among them, the distance between the edge of the through hole (the inner edge of the remaining part of the fourth copper interface after punching) and the edge of the fourth copper interface (at this time, this edge is the outer edge of the remaining part of the fourth copper interface) is less than or equal to the punching distance, and the punching distance is the distance between the gold finger shape and the gold finger edge, so that the through hole formed by punching can be punched according to the gold finger shape, and the simulation of the gold finger punching is truly realized; the distance between the edge of the fourth copper interface (that is, the outer edge of the remaining part of the fourth copper interface) and the gold finger shape is greater than or equal to the minimum distance of the die cutting edge, which can ensure the normal realization of the through hole punching.

[0079] Specifically, in this embodiment, the top view structure of the punching detection mark after being punched by S3 is as Figure 3 shown, and the top view structure of the gold finger and the gold finger shape on the target flexible circuit board after being punched by S3 is as Figure 4 shown. In Figure 4 , the punching detection mark 1 is located in the waste area near the gold finger shape 3, the gold finger 2 is located inside the gold finger shape 3, and the punching distance between the edge of the gold finger 2 and the gold finger shape 3 has three-directional distances, as Figure 4A, B, and C in [description] are respectively the distance between the upper edge of the gold finger 2 and the upper side line of the gold finger outer shape 3, the distance between the left edge of the gold finger 2 and the left side line of the gold finger outer shape 3 (wherein, both the left edge and the left side line are irregular lines. Since the punching distance is the minimum distance between the edge of the gold finger and the gold finger outer shape, this distance takes the minimum distance between the left edge and the left side line), and the distance between the right edge of the gold finger 2 and the right side line of the gold finger outer shape 3 (similarly, this distance takes the minimum distance between the right edge and the right side line; and since the area below the gold finger 2 is other circuits and is also included in the gold finger outer shape 3, therefore, when punching, the distance between the lower edge of the gold finger 2 and the lower side line of the gold finger outer shape 3 does not need to be considered, and the specific structure of the area below the gold finger 2 is not shown); and because the gold finger is symmetric left and right, that is, there is a relationship of B = C, so the punching distance between the edge of the gold finger 2 and the gold finger outer shape 3 mainly includes these two distances A and B. In Figure 3 there are four-direction distances between the edge of the through hole 18 and the edge of the fourth copper interface 14, that is Figure 3 A', B', C', and D' in [description] are respectively the distance between the uppermost point of the edge of the through hole 18 and the upper edge of the fourth copper interface 14, the distance between the rightmost point on the edge of the through hole 18 and the right edge of the fourth copper interface 14, the distance between the lowermost point of the edge of the through hole 18 and the lower edge of the fourth copper interface 14, and the distance between the leftmost point on the edge of the through hole 18 and the left edge of the fourth copper interface 14. Similarly, there is a relationship of A' = C' and B' = D', that is, there are also these two distances A' and B' between the edge of the through hole 18 and the edge of the fourth copper interface 14.

[0080] In this embodiment, the distance between the edge of the through hole 18 and the edge of the fourth copper interface 14 is less than or equal to the punching distance, specifically referring to A' ≤ A and B' ≤ B; for example, if A = 0.15 mm, then it is required that A' ≤ 0.15 mm (or C' ≤ 0.15 mm); if B = 0.05 mm, then it is required that B' ≤ 0.05 mm (or D' ≤ 0.05 mm); if A = B = 0.1 mm, then it is required that A' ≤ 0.1 mm (or C' ≤ 0.1 mm) and B' ≤ 0.1 mm (or D' ≤ 0.1 mm).

[0081] In this embodiment, since the through hole 18 is located on the left side of the finger profile 3, in order to ensure the connection between the edge of the through hole 18 and the outer edge of the remaining part of the fourth copper interface after punching, the distance between the edge of the fourth copper interface and the finger profile 3 specifically refers to the distance between the rightmost point on the outer edge of the remaining part of the fourth copper interface and the finger profile 3 (since the finger profile is an irregular line, this distance refers to the minimum distance between the rightmost point on the outer edge of the remaining part of the fourth copper interface and the finger profile. When this minimum distance is defined, the remaining larger distances are also restricted within the range satisfied by this minimum distance, truly ensuring the connection between the through hole edge and the outer edge of the remaining part of the fourth copper interface), that is Figure 4 E in Figure 4 ; when the minimum distance between the die cutting edges is 0.5 mm, then it is required that E ≥ 0.5 mm.

[0082] The punching distances represented by A, B, and C and the minimum die cutting edge distance in this embodiment are all preset in advance according to the actual situation in the preset punching design.

[0083] As Figure 1 shown in S4, perform electrical testing on the target flexible printed circuit board, and at the same time perform electrical testing on the punching detection marks after punching, and obtain the finger punching result according to the electrical testing result of the punching detection marks.

[0084] Preferably, the electrical testing results include the first testing result between the first copper interface and the third copper interface, the second testing result between the second copper interface and the first copper interface, and the third testing result between the second copper interface and the third copper interface;

[0085] In S4, performing electrical testing on the punching detection marks after punching and obtaining the finger punching result according to the electrical testing result of the punching detection marks includes:

[0086] S41: Connect a first testing needle to the first copper interface, two second testing needles to the second copper interface, and a third testing needle to the third copper interface, and perform electrical testing on the punching detection marks according to the first testing needle, the two second testing needles, and the third testing needle, and respectively obtain the first testing result, the second testing result, and the third testing result;

[0087] S42: If the first testing result is an open circuit, then determine that the finger punching result is that the finger has a punching offset;

[0088] If the first testing result is a conduction, and both the second testing result and the third testing result are open circuits, then determine that the finger punching result is that the finger punching is normal;

[0089] If the first test result is conduction, and both the second test result and the third test result are short circuits, it is determined that the result of the gold finger punching is that the gold finger is missed in punching.

[0090] Based on two different copper interfaces in the punching detection mark after punching, two types of test pins are respectively connected. The first type is a first test pin and a third test pin respectively connected to the first copper interface and the third copper interface, and the second type is two second test pins connected to the second copper interface; through these two types of test pins, different test results can be measured respectively; according to different test results, different defective conditions (including punching deviation and missed punching) during the gold finger punching process can be detected. Since both the first copper interface and the third copper interface are connected to the remaining part after punching of the fourth copper interface, when the first test result between the first copper interface and the third copper interface is open circuit, it indicates that the fourth copper interface has been punched and its punching process has cut off its remaining part, thus causing its remaining part to be unable to conduct, that is, the punching process does not perform punching according to the preset punching design. At this time, without considering the second test result between the second copper interface and the first copper interface and the third test result between the second copper interface and the third copper interface, it can be determined that the gold finger has punching deviation, as Figure 5A shown.

[0091] When the first test result is conduction, it indicates that the state between the first copper interface and the third copper interface is conduction. It may be that the fourth copper interface has not been punched, or the fourth copper interface is normally punched according to the preset punching design so that its remaining part has not been cut off. At this time, the second test result and the third test result need to be further considered; if both the second test result and the third test result are open circuits, it indicates that based on the normal punching of the fourth copper interface according to the preset punching design, the second copper interface is connected to the through hole formed by punching in the fourth copper interface and cannot conduct with the remaining part of the fourth copper interface, presenting an open circuit state, then it can be determined that the gold finger punching is normal, as Figure 5B shown; if both the second test result and the third test result are short circuits, it indicates that based on the fourth copper interface not being punched, the second copper interface is still conducting with the copper fourth copper interface, presenting a short circuit state, then it can be determined that the gold finger has missed punching, as Figure 5C shown.

[0092] Among them, when two test pins are connected to the second copper interface instead of one test pin and the two test pins are of the same network, it can avoid the pseudo open circuit state caused by one test pin being bent and not contacting the fourth copper interface, resulting in misjudging that the punching is normal when the gold finger has punching abnormality and missing defective products. That is, by connecting two test pins to the second copper interface, the misjudgment rate can be reduced, and further the missing risk can be reduced.

[0093] Preferably, the number of the original flexible printed circuit boards is one or more.

[0094] An original flexible printed circuit board is used to manufacture a single-piece flexible board product. Through multiple original flexible printed circuit boards, it can be used for mass production of flexible board products.

[0095] When the number of original flexible printed circuit boards is one, the number of gold fingers fabricated thereon can be one or multiple. Whether there is one or multiple gold fingers, their punching is achieved in the same manufacturing process. Therefore, by fabricating a corresponding punching detection mark on the waste area (near the gold finger contour area) of this single original flexible printed circuit board, the detection of defective punching of the gold fingers can be realized; when the number of original flexible printed circuit boards is multiple, the number of gold fingers fabricated on each original flexible printed circuit board can be one or multiple. Similarly, whether there is one or multiple, the punching of the gold fingers on each original flexible printed circuit board is also achieved in the same manufacturing process. Therefore, by fabricating a corresponding punching detection mark on the waste area (near the gold finger contour area) of each original flexible printed circuit board, the detection of defective punching of the gold fingers of each original flexible printed circuit board can be realized.

[0096] In a specific implementation manner of this embodiment, when there are multiple original flexible printed circuit boards and one gold finger is fabricated on each original flexible printed circuit board, the layout diagram of the fabricated punching detection marks is as Figure 6A shown, and each original flexible printed circuit board corresponds to one punching detection mark; when there are multiple original flexible printed circuit boards and two gold fingers are fabricated on each original flexible printed circuit board, the layout diagram of the fabricated punching detection marks is as Figure 6B and 6C shown. Similarly, each original flexible printed circuit board corresponds to one punching detection mark. In Figures 6A - 6C , 4 is the original flexible printed circuit board.

[0097] The method for detecting defective punching of the gold fingers on the flexible printed circuit board of this embodiment, by simultaneously fabricating, punching, and electrically testing the punching detection marks during the conventional manufacturing processes of fabricating, punching, and electrically testing the gold fingers, does not require an additional fabrication process for the punching detection marks, and at the same time improves the production efficiency and inspection efficiency; by using the punching of the punching detection marks to simulate the gold finger punching process, the electrical testing based on this punching detection mark can effectively control the products with defective punching of the gold fingers, overcoming the problem that it is difficult to detect defective punching during the gold finger punching, resulting in a risk of omission, and effectively improving the detection rate of defective products.

[0098] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A detection method for poor stamping of gold fingers on a flexible printed circuit board, characterized in that, Including: Providing an original flexible printed circuit board provided with a gold finger punching area and a punching detection mark making area; Manufacturing a gold finger on the gold finger punching area of the original flexible printed circuit board, and at the same time manufacturing a punching detection mark on the punching detection mark making area to obtain a circuit board to be punched; According to a preset punching design, performing outer shape punching on the gold finger on the gold finger punching area of the circuit board to be punched; at the same time, according to the preset punching design, performing punching on the punching detection mark to obtain a target flexible printed circuit board; Performing electrical testing on the target flexible printed circuit board, and at the same time performing electrical testing on the punched punching detection mark, and obtaining a gold finger punching result according to the electrical testing result of the punching detection mark; The punching detection mark includes a first copper interface, a second copper interface, a third copper interface, a fourth copper interface, a first circuit, a second circuit and a third circuit; The first copper interface is connected to the fourth copper interface through the first circuit, the second copper interface is connected to the fourth copper interface through the second circuit, and the third copper interface is connected to the fourth copper interface through the third circuit; Wherein, the first circuit, the second circuit and the third circuit are not connected to each other, and the first circuit, the second circuit and the third circuit are all spaced apart according to a preset etching pitch; the connection points between the first circuit and the fourth copper interface and the connection points between the third circuit and the fourth copper interface are both located at the edge of the fourth copper interface, and the connection point between the second circuit and the fourth copper interface is close to the center of the fourth copper interface.

2. The detection method for poor stamping of the gold fingers on the flexible printed circuit board according to claim 1, characterized in that, The punching detection mark making area is located on the waste area near the gold finger punching area on the original flexible printed circuit board, and the gold finger manufactured on the gold finger punching area and the punching detection mark manufactured on the punching detection mark making area are located on the same side of the circuit board to be punched.

3. The detection method for the poor punching of the gold fingers on the flexible printed circuit board according to claim 1, characterized in that, The manufacturing the gold finger on the gold finger punching area of the original flexible printed circuit board and at the same time manufacturing the punching detection mark on the punching detection mark making area to obtain the circuit board to be punched includes: Adopting an etching process, etching the gold finger on the gold finger punching area of the original flexible printed circuit board according to a preset gold finger design; at the same time, etching the punching detection mark on the punching detection mark making area of the original flexible printed circuit board according to a preset mark design to obtain the circuit board to be punched.

4. The detection method for poor stamping of gold fingers on a flexible printed circuit board according to claim 1, characterized in that, The preset punching design includes the minimum distance between the die cutting edges and the punching distance between the edge of the gold finger and the outer shape of the gold finger.

5. The detection method for poor stamping of the gold fingers on the flexible printed circuit board according to claim 4, characterized in that, The performing punching on the punching detection mark according to the preset punching design includes: Performing punching on the fourth copper interface on the punching detection mark to form a through hole in the fourth copper interface, so that the first copper interface is connected to the remaining part of the fourth copper interface through the first circuit, and the third copper interface is connected to the remaining part of the fourth copper interface through the third circuit, and the second copper interface is also connected to the through hole through the second circuit; Wherein, the distance between the edge of the through hole and the edge of the fourth copper interface is less than or equal to the punching distance, and the distance between the edge of the through hole of the fourth copper interface and the outer shape of the gold finger is greater than or equal to the minimum distance of the die cutting edge.

6. The detection method for poor stamping of the gold fingers on the flexible printed circuit board according to claim 5, characterized in that, The electrical test results include a first test result between the first copper interface and the third copper interface, a second test result between the second copper interface and the first copper interface, and a third test result between the second copper interface and the third copper interface; Performing an electrical test on the punched punching detection mark, and obtaining a gold finger punching result according to the electrical test result of the punching detection mark, including: Connecting a first test pin to the first copper interface, two second test pins to the second copper interface, and a third test pin to the third copper interface, and performing an electrical test on the punching detection mark according to the first test pin, the two second test pins, and the third test pin, respectively obtaining the first test result, the second test result, and the third test result; If the first test result is an open circuit, it is determined that the gold finger punching result is that the gold finger has a punching offset; If the first test result is conductive, and both the second test result and the third test result are open circuits, it is determined that the gold finger punching result is that the gold finger is punched normally; If the first test result is conductive, and both the second test result and the third test result are short circuits, it is determined that the gold finger punching result is that the gold finger has a missed punch.

7. The detection method for the poor punching of the gold fingers on the flexible printed circuit board according to claim 4, wherein Before performing the outer shape punching of the gold finger on the gold finger punching area of the to-be-punched circuit board according to the preset punching design, it further includes: Sticking a protective film on all areas of the to-be-punched circuit board except the gold finger punching area, the first copper interface, the second copper interface, and the third copper interface.

8. The detection method for poor stamping of the gold fingers on the flexible printed circuit board according to claim 7, characterized in that, The distances between the protective film and the edges of the first copper interface, the second copper interface, and the third copper interface are all greater than the preset fitting tolerance; and / or, the distance between the protective film and the outer shape of the gold finger is greater than the preset fitting tolerance.

9. The detection method for poor stamping of gold fingers on a flexible printed circuit board according to claim 1, wherein The original flexible circuit board is a single-sided board, a double-sided board, or a multi-layer board.

10. The detection method for poor stamping of the gold fingers on the flexible printed circuit board according to any one of claims 1 to 9, characterized in that, The number of the original flexible circuit boards is one or more.

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