Rivet of circuit board and circuit board

Abstract

The utility model provides a rivet of a circuit board and the circuit board, and relates to the technical field of electronics. The rivet is provided with a rivet cap and a rivet rod, the outer diameter of the rivet cap is D1, the outer diameter of the rivet rod is D2, D1 is larger than or equal to 4.100 mm and larger than or equal to 3.900 mm, and D2 is larger than or equal to 3.200 mm and larger than or equal to 3.175 mm. On the premise of keeping the original pressing process unchanged, the outer diameter of the rivet cap is reduced, and only the rivet is simply improved, so that the extrusion of the rivet on the inner-layer core plate is reduced, and the product quality is improved.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a rivet for a circuit board and a circuit board. Background Art

[0002] Multilayer boards are typically laminated using a combination of hot melt and riveting. During this process, the inner core of the printed circuit board is squeezed by the rivet caps, causing deformation. This is especially true for small-patch boards, which are larger and have smaller edge margins. Deformation deviations of a dozen or so microns can increase the risk of short circuits. Therefore, for boards with higher alignment requirements, even more attention to detail is required during the lamination process. Utility Model Content

[0003] In view of this, the purpose of this application is to overcome the shortcomings of the existing technology and provide a rivet for a circuit board and a circuit board. By reducing the outer diameter of the rivet cap while maintaining the original pressing process unchanged, only simple improvements are made to the rivet to reduce the extrusion of the rivet on the inner core board and improve product quality.

[0004] This application provides the following technical solutions:

[0005] In a first aspect, an embodiment of the present application provides a rivet for a circuit board, wherein the rivet has a rivet cap and a rivet rod, the outer diameter of the rivet cap is D1, the outer diameter of the rivet rod is D2, and the following conditions are satisfied: 4.100 mm ≥ D1 ≥ 3.900 mm, 3.200 mm ≥ D2 ≥ 3.175 mm.

[0006] In some embodiments of the first aspect, the outer diameter of the rivet head is D1, and D1 = 4 mm.

[0007] In some embodiments of the first aspect, the outer diameter of the rivet stem is D2, and D2 = 3.175 mm.

[0008] In some embodiments of the first aspect, the thickness of the rivet cap is H, and satisfies: 0.225 mm ≥ H ≥ 0.175 mm.

[0009] In some embodiments of the first aspect, the rivet cap has a thickness H, where H=0.2 mm.

[0010] In some embodiments of the first aspect, the rivet cap has a shank end surface, the flatness of the shank end surface is F, and satisfies: 0.05 mm ≥ F ≥ 0.005 mm.

[0011] In a second aspect, the present application further provides a circuit board, comprising:

[0012] The rivet for a circuit board as described in any one of the above embodiments;

[0013] The core plate layer group comprises a rivet hole, the rivet rod is passed through the rivet hole, and the rivet rod and the rivet hole are loosely matched.

[0014] In some embodiments of the second aspect, the maximum gap between the rivet rod and the rivet hole is Max, the minimum gap between the rivet rod and the rivet hole is Mix, and the following conditions are satisfied: Max = 0.002 mm, Mix = 0 mm.

[0015] In some embodiments of the second aspect, the core board layer group includes N levels of chips, the N levels of chips are stacked, and a dielectric is provided between two adjacent chips; wherein, the first-level chip and the rivet cap are abutted, and the thickness of the dielectric between the first-level chip and the second-level chip is L, and satisfies: 0.200mm≥L≥0.050mm, N≥2, and N is a positive integer.

[0016] In some embodiments of the second aspect, the rivet hole includes a plurality of hole segments connected in sequence, and inner diameters of the plurality of hole segments decrease in sequence in a direction away from the rivet cap.

[0017] The embodiments of the present application have the following advantages:

[0018] The present application provides a rivet for a circuit board. The present application adds an inner liner box for use with a middle plate, which effectively reduces the time the pipette tip is exposed to the outside and reduces the risk of contamination. In addition, the provision of the positioning portion ensures good compatibility between the circuit board rivet and the automated pipetting device, does not affect the normal use of the middle plate and the carrier, and improves operational efficiency. It is particularly suitable for laboratory environments that require high precision and low contamination requirements, such as biomedical research, clinical diagnosis and other fields. By reducing pipette tip contamination, the accuracy of experimental results can be improved, and the cost of experimental failure or repeated experiments due to contamination can be reduced.

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 A schematic structural diagram of a rivet provided by an embodiment of the present application from one perspective is shown;

[0022] Figure 2 A schematic diagram showing the structure of a circuit board provided by one embodiment of the present application using a rivet cap with an outer diameter of 5.5 mm;

[0023] Figure 3 A schematic diagram showing the structure of a circuit board provided by one embodiment of the present application using a rivet cap with an outer diameter of 4 mm;

[0024] Figure 4 A schematic structural diagram of a circuit board provided by an embodiment of the present application from one perspective is shown;

[0025] Figure 5 A structural schematic diagram of a circuit board provided in another embodiment of the present application is shown from one perspective.

[0026] Description of main component symbols:

[0027] 100-Rivet; 110-Rivet cap; 120-Rivet rod;

[0028] 200-core board layer group; 210-core board; 220-medium thickness; 230-rivet hole. DETAILED DESCRIPTION

[0029] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0030] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. Conversely, when an element is referred to as being "directly on" another element, there is no intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only.

[0031] In this application, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on specific circumstances.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used in the template description herein are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] As electronic products continue to miniaturize and become more densely packed, printed circuit board designs are becoming increasingly refined and denser. The distance between holes and conductors is shrinking, the number of wiring layers is increasing, and the size is also increasing, making alignment increasingly difficult. The lamination process is the most crucial step in alignment control, so the control of press-fit alignment technology is crucial.

[0035] Multilayer boards are typically laminated using a combination of hot melt and riveting. During this process, the inner core of the printed circuit board is squeezed by the rivet caps, causing deformation. This is especially true for small-pitch boards, which are larger and have smaller edge margins. Rivet position deviation is particularly critical, as even a deviation of a dozen microns can increase the risk of short circuits. Therefore, for boards with higher alignment requirements, even more attention should be paid to detail during the lamination process.

[0036] like Figure 1 、 Figure 2 and Figure 3 As shown, in order to solve the above technical problems, an embodiment of the present application provides a rivet 100 for a circuit board, wherein the rivet 100 has a rivet cap 110 and a rivet rod 120, the outer diameter of the rivet cap 110 is D1, the outer diameter of the rivet rod 120 is D2, and the following conditions are satisfied: 4.100 mm ≥ D1 ≥ 3.900 mm, 3.200 mm ≥ D2 ≥ 3.175 mm.

[0037] In these embodiments, the core of the present application is to reduce the impact on the inner core board 210 during the pressing process by optimizing the design of the rivet 100 of the circuit board, especially for small pitch type circuit boards that require high positioning accuracy. Specifically, this technical solution mainly focuses on adjusting the outer diameter dimensions of the rivet cap 110 (D1) and the rivet rod 120 (D2) to ensure that the deformation problem of the inner core board 210 caused by the excessive size of the rivet cap 110 can be effectively reduced without changing the existing pressing process. The specific range of the outer diameter D1 of the rivet cap 110 mentioned here is between 4.100mm and 3.900mm. The setting of this range has obviously been precisely calculated and experimentally verified, and is intended to balance the functionality of the rivet 100 and reduce the negative impact on the internal structure of the circuit board.

[0038] The rivet cap 110 has a rod end face and a cap end face opposite to each other, and one end of the rivet rod 120 is disposed on the rod end face, and the two are coaxially disposed. Typically, the rivet rod 120 and the rivet cap 110 are integrally disposed.

[0039] Moreover, the specific numerical range of the outer diameter D2 of the rivet rod 120 is "3.200mm≥D2≥3.175mm". Under normal circumstances, the diameter of the rivet rod 120 will be determined after comprehensive consideration of factors such as actual application requirements and riveting strength. A reasonable diameter of the rivet rod 120 not only needs to ensure sufficient mechanical strength, but also needs to take into account the coordination with the rivet hole 230 to avoid problems such as unstable connection caused by excessive gaps or installation difficulties caused by excessive tightness. In addition, the present application needs to consider the difference in the outer diameters of the rivet rod 120 and the rivet cap 110, and thereby ensure that on the basis of meeting the fixing strength of the rivet 100 on the core plate 210, the outer diameter of the rivet cap 110 is reduced to reduce the extrusion of the rivet 100 on the inner core plate 210 and improve product quality. It should be noted that the present application only makes simple improvements to the rivet 100 while maintaining the original pressing process unchanged, which does not affect the normal production process of the circuit board. Obviously, the present application provides a simple and effective solution to improve the quality of circuit boards, especially in situations where extremely high alignment accuracy is required.

[0040] In some embodiments, the outer diameter of the rivet cap 110 is D1, where D1 = 4 mm; and the outer diameter of the rivet stem 120 is D2, where D2 = 3.175 mm.

[0041] In these embodiments, setting the outer diameter D1 of the rivet cap 110 to 4 mm and the outer diameter D2 of the rivet rod 120 to 3.175 mm is a preferred embodiment. In this embodiment, the present application comprehensively considers the difficulty of processing and production and the quality of the circuit board.

[0042] For ease of understanding, the following comparative implementations are provided:

[0043] During the pressing process, the rivet cap 110 will squeeze the core plate 210, and the closer the core plate 210 is to the rivet cap 110, the greater the impact. Figure 2 As shown, the outer diameter of the rivet cap 110 is 5.5 mm. The area where the rivet cap 110 squeezes the inner core panel 210 most severely can be roughly viewed as a triangle ABC. AB is 1851.2 μm long, and BC is 271.3 μm long. Due to the squeezing of the rivet cap 110, the core panel 210, which should have been at position AB, is squeezed to position AC after pressing. Calculation shows that the length AC is 1871.2 μm. The stretched length of the inner core panel 210 is AC - AB: 1871.2 - 1851.2 = 19.7 μm, resulting in a displacement of nearly 1 μm. This can be quite detrimental for products with small pitches.

[0044] When the outer diameter of the rivet cap 110 of the rivet 100 is 4.0 mm, as shown in FIG. Figure 3 As shown in the figure, after pressing, it is obvious that the degree of extrusion and the affected range at the rivet 100 position are significantly reduced. The extruded portion can be approximately viewed as a triangle DEF. DE is 989.8 μm long, EF is 158.9 μm long, and the calculated length of DF is 12.6 μm. The stretched length of the inner core plate 210, DF - DE, is: 989.8 - 158.9 = 12.6 μm.

[0045] The above results show that shortening the rivet cap 110 can effectively reduce the degree and range of the squeeze of the rivet cap 110 on the core plate 210. However, it should be noted that if the outer diameter of the rivet cap 110 is too small, there is a possibility that the rivet 100 will not be able to hold the inner core plate 210.

[0046] like Figure 1 As shown, in some embodiments, the thickness of the rivet cap 110 is H, and satisfies: 0.225 mm ≥ H ≥ 0.175 mm.

[0047] In these embodiments, not only the outer diameters of the rivet head 110 and the rivet stem 120 are involved, but also the thickness of the rivet head 110 is particularly emphasized.

[0048] By adjusting the thickness of the rivet cap 110, the riveting effect is further optimized and the mechanical stress on the circuit board is reduced. Among them, the minimum thickness ensures that the rivet cap 110 can form an effective connection during the pressing process while reducing the pressure on the circuit board.

[0049] Maximum thickness: to prevent the rivet cap 110 from being too thick, which may cause excessive pressure on the circuit board during the pressing process, causing deformation or damage.

[0050] In some embodiments, the rivet cap 110 has a thickness H, where H=0.200 mm.

[0051] In these embodiments, the thickness of the rivet cap 110 is set to 0.200 mm, thereby enabling the rivet cap 110 to meet the strength requirements while reducing the extrusion deformation of the core plate 210. In this case, the production difficulty of the rivet cap 110 is also reduced accordingly.

[0052] In some embodiments, the rivet cap 110 has a shank end surface, the flatness of the shank end surface is F, and satisfies: 0.05 mm ≥ F ≥ 0.005 mm.

[0053] In these embodiments, the flatness of the rod end face of the rivet cap 110 is beneficial to controlling the contact condition of the rod end face with the uppermost core board 210, that is, the contact stability, which is beneficial to reducing the pressure on the inner layer of the circuit board and preventing the core board 210 from being deformed or damaged.

[0054] In other words, by controlling the flatness of the rod end face, the contact surface between the rivet cap 110 and the circuit board is ensured to be flat during the riveting process, reducing localized pressure concentration and improving riveting quality and stability. This involves two variables: minimum flatness and maximum flatness.

[0055] Minimum flatness: Ensure the end surface is sufficiently flat to avoid excessive local pressure caused by unevenness, which may cause damage to the circuit board. In this embodiment, the minimum flatness is 0.005mm.

[0056] Maximum flatness: Prevents the end surface from being too rough, which would affect the riveting effect and connection reliability. In this embodiment, the maximum flatness is 0.05 mm.

[0057] For example, the flatness of the end surface of the shank of the rivet cap 110 in the present application is 0.005 mm, 0.008 mm, 0.01 mm, 0.015 mm, 0.02 mm, 0.025 mm, 0.03 mm, 0.035 mm, 0.04 mm, 0.045 mm or 0.05 mm, etc.

[0058] like Figure 4 As shown, in some embodiments, the present application also provides a circuit board, which includes the rivet 100 and the core board layer group 200 of the circuit board as described in any one of the above embodiments, the core board 210 layer has a rivet hole 230, the rivet rod 120 is passed through the rivet hole 230, and the rivet rod 120 and the rivet hole 230 are clearance-fitted.

[0059] It should be noted that the core board layer group 200 includes multiple layers of core boards 210, and the adjacent core boards 210 are filled with dielectric 220. The rivet holes 230 are pre-set on the circuit board, and then the rivet rod 120 is inserted into the rivet hole 230. In a heated environment, the rivet cap 110 is used to squeeze the circuit board so that the dielectric 220 melts and fills the gap between the rivet rod 120 and the rivet hole 230.

[0060] Since the rivet 100 for the circuit board has the above-mentioned technical effects, the automated liquid transfer device including the rivet 100 for the circuit board should have the same technical effects, which will not be described in detail here.

[0061] In some embodiments, the maximum gap between the rivet rod 120 and the rivet hole 230 is Max, and the minimum gap between the rivet rod 120 and the rivet hole 230 is Mix, and they satisfy: Max=0.020 mm, Min=0 mm.

[0062] Typically, the tolerance range of the clearance fit between the rivet stem 120 and the rivet hole 230 is ±0.010 mm.

[0063] For example, the gap value between the rivet stem 120 and the rivet hole 230 may be 0.01, 0.015, or 0.02, etc.

[0064] In some embodiments, the core board layer group 200 includes N levels of chips, which are stacked and a dielectric 220 is provided between two adjacent chips; wherein the first-level chip and the rivet cap 110 are in contact with each other, and the thickness of the dielectric 220 between the first-level chip and the second-level chip is L, and satisfies: 0.200mm≥L≥0.050mm, N≥2, and N is a positive integer.

[0065] In these embodiments, the degree of extrusion of the core plate by the rivet position is also affected by the thickness of the secondary outer layer dielectric (i.e., the dielectric thickness 220 between the first-level chip and the second-level chip). The dielectric thickness acts to buffer the extrusion of the secondary outer layer core plate by the rivet cap. Under the premise that the pressing thickness allows, the thicker the secondary outer layer dielectric is, the lower the degree of extrusion of the core plate by the rivet cap will be, and the thinner the dielectric is, the greater the degree of extrusion.

[0066] For example, the thickness of the dielectric between the chip at the first level and the chip at the second level may be 0.050 mm, 0.080 mm, 0.100 mm, 0.150 mm, 0.180 mm, or 0.200 mm, etc.

[0067] In some embodiments, the rivet hole 230 includes a plurality of hole segments that are connected in sequence, and the inner diameters of the plurality of hole segments decrease in sequence in a direction away from the rivet cap 110 .

[0068] like Figure 5As shown, in these embodiments, core panel assembly 200 is comprised of multiple core panels 210, each of which has a pre-drilled rivet hole 230. The diameter of rivet hole 230 is slightly larger than the outer diameter of rivet shank 120 to ensure smooth insertion of rivet shank 120. Rivet hole 230 comprises a plurality of sequentially connected hole segments, with the inner diameters of the multiple hole segments decreasing in a direction away from rivet cap 110.

[0069] This design can better guide the rivet shank 120 into the hole, reduce deviation and misalignment during assembly, and improve the accuracy and reliability of riveting. For example, the inner diameter of the first hole section is slightly larger than the outer diameter of the rivet shank 120, the inner diameter of the second hole section is smaller than the inner diameter of the first hole section, and the inner diameter of the third hole section is smaller than the inner diameter of the second hole section.

[0070] Optionally, the size and shape of the rivet cap 110 and the rivet rod 120 meet the requirements to reduce the pressure on the inner layer of the circuit board. The multi-stage design between the rivet rod 120 and the rivet hole 230 ensures that the rivet rod 120 can be smoothly inserted during the riveting process, reducing assembly errors and improving the accuracy and reliability of the riveting.

[0071] For example, the rivet hole 230 is configured as a tapered hole. Of course, the rivet hole 230 can also be configured as a trapezoidal hole, etc. Of course, the rivet rod 120 can also be configured as a tapered rod. Alternatively, the rivet rod 120 can also be configured as a trapezoidal rod.

[0072] In all examples shown and described herein, any specific values ​​should be interpreted as merely exemplary and not limiting, and thus other examples of the exemplary embodiments may have different values.

[0073] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0074] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the scope of the present application, and such modifications and improvements are all within the scope of protection of the present application.

Claims

1. A rivet for a circuit board, characterized in that: The rivet includes a rivet cap and a rivet rod. The outer diameter of the rivet cap is D1, the outer diameter of the rivet rod is D2, and the following conditions are satisfied: 4.100 mm ≥ D1 ≥ 3.900 mm, 3.200 mm ≥ D2 ≥ 3.175 mm.

2. The rivet for a circuit board according to claim 1, wherein: The outer diameter of the rivet cap is D1, D1=4 mm.

3. The rivet for a circuit board according to claim 1 or 2, characterized in that: The outer diameter of the rivet rod is D2, where D2=3.175 mm.

4. The rivet for a circuit board according to claim 1, wherein: The thickness of the rivet cap is H, and satisfies: 0.225mm≥H≥0.175mm.

5. The rivet for a circuit board according to claim 4, characterized in that: The thickness of the rivet cap is H, H=0.2 mm.

6. The rivet for a circuit board according to claim 1, wherein: The rivet cap has a shank end surface, the flatness of the shank end surface is F, and satisfies: 0.05mm≥F≥0.005mm.

7. A circuit board, characterized in that: The circuit board comprises: The rivet for a circuit board according to any one of claims 1 to 6; The core plate layer group comprises a rivet hole, the rivet rod is passed through the rivet hole, and the rivet rod and the rivet hole are loosely matched.

8. The circuit board according to claim 7, wherein: The maximum gap between the rivet rod and the rivet hole is Max, the minimum gap between the rivet rod and the rivet hole is Mix, and the following conditions are satisfied: Max=0.020 mm, Min=0 mm.

9. The circuit board according to claim 7, wherein: The core board layer group includes N levels of chips, which are stacked and a dielectric is provided between two adjacent chips; wherein, the first-level chip and the rivet cap are abutted, and the thickness of the dielectric between the first-level chip and the second-level chip is L, and satisfies: 0.200mm≥L≥0.050mm, N≥2, and N is a positive integer.

10. The circuit board according to claim 7, wherein: The rivet hole includes a plurality of hole segments that are connected in sequence, and the inner diameters of the plurality of hole segments decrease in sequence in a direction away from the rivet cap.

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