Multi-layer FPC board convenient for interlayer alignment detection
By designing the alignment structure formed by hollow patterns on the multi-layer FPC board, including the first window opening and marking ring, the problem of low design efficiency and low accuracy of traditional detection methods is solved, and efficient and accurate interlayers are achieved Alignment detection.
Patent Information
- Application Number
- CN202421093326.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-17
- Publication Date
- 2025-02-14
- Estimated Expiration
- 2034-05-17
AI Technical Summary
The traditional multi-layer FPC board-layer alignment detection method has low design efficiency and low accuracy, making it difficult to meet the requirements of high quality and low cost.
A multi-layer FPC board is designed, and an alignment structure is formed by setting a hollow pattern on the circuit board, including a first window opening and a marking ring. The transparent insulating film allows the marking ring of each layer of circuit board to pass through the previous layer. Observe to realize intuitive detection of inter-layer alignment.
This design improves the accuracy and efficiency of interlayer alignment detection, and can intuitively obtain the accurate values of interlayer alignment, meeting the requirements of high quality and low cost.
Smart Images
Figure CN222484991U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of flexible circuit boards, in particular to a multi-layer FPC board which is convenient for detecting inter-layer alignment. Background Art
[0002] PCB is a hard printed circuit board made of a hard insulating substrate, usually referred to as a "hard board". Due to the unbendable nature of PCB, it is difficult to use in many electronic products.
[0003] FPC, or flexible printed circuit board, is a printed circuit board made of a flexible insulating substrate, usually referred to as "soft board". The flexible insulating substrate mainly refers to polyimide film or polyester film. Polyimide film is also called PI film. Polyimide film is a light yellow transparent material, and polyester film is colorless and transparent. It has many advantages that rigid printed circuit boards do not have. For example, it can be bent, wound, and folded freely. The use of FPC can greatly reduce the size of electronic products, which is suitable for the development of electronic products towards high density, miniaturization, and high reliability.
[0004] With the continuous increase in the number of FPC layers and the decrease in line width spacing, the requirements for interlayer alignment are becoming higher and higher. The interlayer alignment directly affects the electrical function of the FPC product. Providing the interlayer alignment data of the product when the FPC product is shipped is also an important measure of product quality. With the increase in the number of FPC layers, the line width spacing on the circuit layer becomes smaller, which makes the requirements for the interlayer alignment of multi-layer FPC boards higher and higher.
[0005] However, the traditional measurement of interlayer alignment mainly relies on the concentric circles drawn on the multilayer FPC board. The penetration of X-ray is used to observe whether the concentric circles on the opaque inner circuit layer of the multilayer FPC board are tangent to determine whether the basic interlayer alignment requirements of the product are met. The concentric circle alignment structure on the traditional multilayer FPC board has the disadvantages of low design efficiency and low accuracy, which is contrary to the pursuit of high quality and low cost of products. Utility Model Content
[0006] Based on this, it is necessary to provide a multilayer FPC board that is convenient for inter-layer alignment detection.
[0007] In order to solve the above technical problems, the utility model provides a multi-layer FPC board which is convenient for inter-layer alignment detection, comprising a plurality of circuit boards stacked in sequence, wherein the circuit board comprises an insulating film and a copper film, wherein the copper film is covered on the surface of the insulating film, and a hollow pattern is arranged on the copper film, so that the circuit board forms an alignment structure, wherein the alignment structure comprises a first window and a marking ring, wherein the marking ring is located in the first window, and the diameters of the marking rings on the plurality of circuit boards are all different, and the insulating film is a transparent film, and the marking ring of each layer of the circuit board can be observed through the marking ring of the circuit board on the previous layer.
[0008] Preferably, the outer circumference of the marking ring of the circuit board is spaced apart from the boundary of the first opening window.
[0009] Preferably, when the multilayer FPC board is viewed from a top view, the marking rings of the plurality of circuit boards are spaced from the inside to the outside, so that there is a spacing between two marking rings on adjacent stacked circuit boards.
[0010] Preferably, the diameters of the first openings on a plurality of circuit boards are the same, the line widths of the marking rings on any circuit board are the same, and the spacing between two marking rings on any adjacent circuit boards is the same.
[0011] Preferably, the insulating film is a polyimide film or a polyester film.
[0012] Preferably, the line width of the marking ring is in the range of 35-50 μm, and the spacing between the marking rings on two adjacent laminated circuit boards is in the range of 50-100 μm.
[0013] Preferably, the line width of the marking ring is in the range of 35-40 μm, and the line spacing between the marking rings on two adjacent laminated circuit boards is in the range of 60-80 μm.
[0014] Preferably, if the inner protective film or build-up material layer of the multi-layer FPC board is a non-transparent material, a second window is provided on the inner protective film or build-up material layer, and the position of the second window is opposite to the position of the first window.
[0015] Preferably, the first window and the second window are both circular, the diameter of the second window is larger than the diameter of the largest marking ring, and the difference between the diameter of the second window and the diameter of the largest marking ring is in the range of (0-1) mm.
[0016] Preferably, a process edge is provided at the edge of the circuit board, and the marking ring is provided on the process edge.
[0017] Beneficial effects of the utility model: The multilayer FPC board of the present application, through the first windows and marking rings on multiple circuit boards, utilizes the first windows obtained by hollowing out the copper layer, so that outer layer light can pass through the first windows, and has the advantage of being able to intuitively obtain the accurate numerical value of the inter-layer alignment. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above and other purposes, features and advantages of the present invention will become more apparent through a more specific description of the preferred embodiments of the present invention shown in the accompanying drawings. The same reference numerals in all the accompanying drawings indicate the same parts, and the drawings are not intentionally scaled to the actual size, but the focus is on illustrating the subject matter of the present invention.
[0019] Figure 1 A partial top view schematic diagram of the design of marking ring graphics of different sizes for each layer of the preferred embodiment of the utility model;
[0020] Figure 2 for Figure 1 The marked circular rings of each circuit layer at BB` in the middle are stacked to form a cross-sectional view of concentric marked circular rings;
[0021] Figure 3 This is a schematic diagram of the window opening position when the interlayer medium is a non-transparent material in a preferred embodiment of the present invention;
[0022] Figure 4 A top view of a fourth circuit board according to a preferred embodiment of the present invention;
[0023] Figure 5 A top view of a third circuit board according to a preferred embodiment of the present invention;
[0024] Figure 6 A top view of a second circuit board according to a preferred embodiment of the present invention;
[0025] Figure 7 A top view of a first circuit board according to a preferred embodiment of the present invention;
[0026] In the figure: first circuit board 11; second circuit board 12; third circuit board 13; fourth circuit board 14; circuit pattern area 2; first marking ring 31; second marking ring 32; third marking ring 33; first window 41; second window 42; process edge 7; line width D; line spacing L; dielectric layer 9. DETAILED DESCRIPTION
[0027] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings.
[0028] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to another element and integrated therewith, or there may be an intermediate element at the same time. The terms "installed", "one end", "the other end" and similar expressions used herein are for illustrative purposes only.
[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art. The terms used in the specification herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.
[0030] refer to Figure 1-Figure 7 The utility model provides a multi-layer FPC board which is convenient for inter-layer alignment detection, comprising a plurality of circuit boards stacked in sequence, wherein the circuit board comprises an insulating film and a copper film, wherein the insulating film is a transparent film, and the copper film is covered on the surface of the insulating film, and a hollow pattern is arranged on the copper film, so that the circuit board forms an alignment structure, wherein the alignment structure comprises a first opening window 41 and a marking ring, wherein the marking ring is located in the first opening window 41, and the diameters of the marking rings on the plurality of circuit boards are all different, and the marking ring of each layer of the circuit board can be observed through the marking ring of the circuit board of the previous layer.
[0031] Reference Image Figure 4-Figure 7 In a preferred embodiment, the outer perimeter of the marking ring of the circuit board is spaced apart from the boundary of the first opening window 41 .
[0032] refer to Figure 1-Figure 3 In a preferred embodiment, when the multilayer FPC board is viewed from a top view, the marking rings of the plurality of circuit boards are spaced from the inside to the outside, so that there is a spacing L between two of the marking rings on adjacent stacked circuit boards.
[0033] refer to Figure 2 and Figure 3 In a preferred embodiment, the diameters of the first openings 41 on multiple circuit boards are the same, the line widths D of the marking rings on any circuit board are the same, and the spacing L between two marking rings on any adjacent circuit boards is the same.
[0034] In a preferred embodiment, the insulating film is a polyimide film or a polyester film.
[0035] refer to Figure 1 In a preferred embodiment, the line width D of the marking ring is in the range of 35-50 μm, and the line spacing L between the marking rings on two adjacent laminated circuit boards is in the range of 50-100 μm.
[0036] refer to Figure 1 In a preferred embodiment, the line width D of the marking ring is in the range of 35-40 μm, and the line spacing L between the marking rings on two adjacent laminated circuit boards is in the range of 60-80 μm.
[0037] refer to Figure 3 In a preferred embodiment, if the inner protective film or the build-up material layer of the multi-layer FPC board is a non-transparent material, a second window 42 is provided on the inner protective film or the build-up material layer, and the position of the second window 42 is directly opposite to the position of the first window 41. When manufacturing the circuit board, according to the position of the marking ring designed on the circuit diagram, the material at the corresponding position on the non-transparent protective film or the non-transparent build-up material layer is hollowed out to obtain the second window 42.
[0038] refer to Figure 3 In a preferred embodiment, the first window 41 and the second window 42 are both circular, the diameter of the second window 42 is larger than the diameter of the largest marking ring, and the difference between the diameter of the second window 42 and the diameter of the largest marking ring is in the range of (0-1) mm.
[0039] In a preferred embodiment, a process edge 7 is provided at the edge of the circuit board, and the marking ring is provided on the process edge 7 .
[0040] The plurality of circuit boards 1 include a first circuit board 11, a second circuit board 12, a third circuit board 13 and a fourth circuit board 14, wherein the second circuit board 12 is superimposed on the upper end surface of the first circuit board 11, the third circuit board 13 is superimposed on the upper end surface of the second circuit board 12, and the third circuit board 13 is superimposed on the upper end surface of the third circuit board 13, and a dielectric layer 9 is disposed between the first circuit board 11 and the second circuit board 12, between the second circuit board 12 and the third circuit board 13, and between the third circuit board 13 and the fourth circuit board 14, wherein the first circuit board 11 The copper layers where the circuit layers on the second circuit board 12, the third circuit board 13 and the fourth circuit board 14 are located are respectively provided with first openings 41, and the first openings 41 of the first circuit board 11, the second circuit board 12 and the third circuit board 13 are respectively provided with first marking rings 31, second marking rings 32 and third marking rings 33 corresponding to each other, and the first opening 41 of the fourth circuit board 14 is not provided with marking rings, so that the marking rings on the inner and outer circuit layers 2 of the multi-layer FPC board are displayed through the first opening 41 of the top layer. When the inner layer of the circuit board is a non-transparent protective film or a non-transparent build-up material layer, that is, when the medium between the two stacked adjacent circuit boards is a non-transparent material, the second opening 42 is dug; when looking down from the top surface of the multi-layer FPC board, the marking rings on the inner and outer circuit layers of the multi-layer FPC board are displayed through the first opening on the fourth circuit board 14 of the top layer.
[0041] Before the multilayer FPC board of the present invention is manufactured, the circuit board must be designed first. When the circuit diagram corresponding to the multiple circuit boards is designed using the drawing software, the line width of the mark ring designed on the circuit diagram and the spacing between the two mark rings on the stacked adjacent circuit boards are fixed to the design software in the form of a script, and are directly generated according to the selection of the script when the next FPC board precision design is performed. The data of the line width D of the mark ring and the line spacing L of the two adjacent mark rings are fixed to the design script of the circuit board, and are directly generated according to the selection of the script when the FPC board precision design is performed. The spacing can be fixedly optimized and designed into a fixed spacing size. By directly using the design software script to generate, there is no need to design separately for a separate circuit board product during the design stage, thereby improving efficiency. During the design, the circuit diagram is still which of the mark rings on each stacked circuit board of the multilayer FPC board is parallel to each other and is a concentric mark ring with the same center line. After the circuit boards are actually manufactured and stacked to make multi-layer FPC boards, due to the difference in inter-layer alignment, the better the alignment between the circuit board layers, the higher the concentricity of the marking rings on each stacked circuit board with the same center line; the worse the alignment between the circuit board layers, the lower the concentricity of the marking rings on each stacked circuit board.
[0042] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.
[0043] In the description of this specification, the description with reference to the terms "preferred embodiment", "further embodiment", "other embodiments" or "specific example" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.
[0044] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.
Claims
1. A multi-layer FPC board that is convenient for inter-layer alignment detection, characterized in that: It comprises a plurality of circuit boards stacked in sequence, the circuit boards comprising an insulating film and a copper film, the copper film being covered on the surface of the insulating film, the copper film being provided with a hollow pattern, so that the circuit boards are formed with an alignment structure, the alignment structure comprising a first window and a marking ring, the marking ring being located in the first window, the diameters of the marking rings on the plurality of circuit boards being different, the insulating film being a transparent film, the marking ring of each layer of the circuit boards being able to be observed through the marking ring of the upper layer of the circuit board.
2. The multilayer FPC board according to claim 1, characterized in that: The outer perimeter of the marking ring of the circuit board is spaced apart from the boundary of the first opening window.
3. The multilayer FPC board according to claim 2, characterized in that: When viewed from above, the marking rings of the plurality of circuit boards of the multilayer FPC board are spaced from the inside to the outside, so that there is a spacing between two marking rings on adjacent stacked circuit boards.
4. The multilayer FPC board according to claim 1, characterized in that: The diameters of the first openings on multiple circuit boards are the same, the line widths of the marking rings on any circuit board are the same, and the spacing between two marking rings on any adjacent circuit boards is the same.
5. The multilayer FPC board according to claim 1, characterized in that: The insulating film is a polyimide film or a polyester film.
6. The multilayer FPC board according to claim 1, characterized in that: The line width of the marking ring is in the range of 35-50 μm, and the spacing between the marking rings on two adjacent laminated circuit boards is in the range of 50-100 μm.
7. The multilayer FPC board according to claim 6, characterized in that: The line width of the marking ring is in the range of 35-40 μm, and the line spacing between the marking rings on two adjacent laminated circuit boards is in the range of 60-80 μm.
8. The multilayer FPC board according to claim 1, characterized in that: If the inner protective film or build-up material layer of the multi-layer FPC board is made of non-transparent material, a second window is provided on the inner protective film or build-up material layer, and the position of the second window is opposite to the position of the first window.
9. The multilayer FPC board according to claim 8, characterized in that: The first window and the second window are both circular, the diameter of the second window is larger than the diameter of the largest marking ring, and the difference between the diameter of the second window and the diameter of the largest marking ring is in the range of (0-1) mm.
10. The multilayer FPC board according to claim 9, characterized in that: A process edge is arranged at the edge of the circuit board, and the marking ring is arranged on the process edge.