Transmission line and method for manufacturing transmission line
By configuring the surrounding conductor around the transmission line conductor and using ultrasonic bonding technology, the transmission loss and space saving problems of the transmission line in electronic equipment during high-speed transmission are solved, and a thin structure with high shielding performance and low loss is achieved.
Patent Information
- Application Number
- CN202380037461.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-07-04
- Filing Date
- 2023-06-28
- Publication Date
- 2024-12-20
AI Technical Summary
The transmission lines of existing electronic devices are difficult to achieve a thin structure that has both shielding performance and space saving, and maintain low transmission losses during high-speed transmission.
By configuring two enclosing conductors around the transmission line conductors and using ultrasonic bonding technology, combining hot crimping and folding end combinations, effective enclosure and connection of the conductors are achieved, ensuring shielding performance and space savings.
Low transmission loss and high shielding performance of transmission lines for high-speed transmission in electronic devices are achieved, while thin configurations are achieved, reducing unnecessary extrusion and heat shrinkage of thermoplastic resins.
Smart Images
Figure CN119174052A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to transmission lines for electronic equipment. Background Art
[0002] Conventionally, there has been proposed a high-frequency signal line, which is configured to include: a dielectric body (liquid crystal polymer) having flexibility; a linear signal line provided in the dielectric body; a ground conductor provided in the dielectric body and opposed to the signal line; an auxiliary ground conductor provided on the opposite side of the ground conductor with respect to the signal line in the normal direction of the main surface of the dielectric body, the auxiliary ground conductor including two main parts and a bridge part, the two main parts sandwiching the signal line when viewed from the normal direction and extending along the signal line, the bridge part connecting the two main parts and crossing the signal line; and a via conductor electrically connecting the auxiliary ground conductor and the ground conductor, wherein the interval between the signal line and the auxiliary ground conductor in the normal direction is smaller than the interval between the signal line and the ground conductor (Patent Document 1: Japanese Utility Model Registration No. 3173143). In addition, a transmission line having the following structure is proposed: a second conductor and a third conductor are arranged to surround the transmission line conductor and the second conductor and the third conductor are ultrasonically bonded (Patent Document 2: Japanese Patent No. 6507302, Patent Document 3: Japanese Patent No. 6611293, Patent Document 4: Japanese Patent No. 6850501).
[0003] Prior art literature
[0004] Patent Literature
[0005] Patent Document 1: Japanese Utility Model Registration No. 3173143
[0006] Patent Document 2: Japanese Patent No. 6507302
[0007] Patent Document 3: Japanese Patent No. 6611293
[0008] Patent Document 4: Japanese Patent No. 6850501 Summary of the invention
[0009] Problems to be solved by the invention
[0010] Transmission lines used in electronic devices are required to have shielding performance, a thin structure to save space, and a structure with low transmission loss to cope with high-speed transmission.
[0011] Means for solving problems
[0012] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a transmission line having a shielding performance, a thin structure for space saving, and a low transmission loss structure capable of high-speed transmission.
[0013] As one embodiment, the above-mentioned problems are solved by the solution means disclosed below.
[0014] The transmission line of the present invention is characterized in that the transmission line comprises: a first conductor, which is composed of a transmission line conductor and a pair of grounding conductors, the pair of grounding conductors being close to the input end and the output end of the transmission line conductor, respectively; a first substrate, which is formed with the first conductor; a covering layer, which covers the transmission line conductor; a first shielding member, which is formed with a second conductor on a second substrate; and a second shielding member, which is formed with a third conductor on a third substrate, the covering layer is thermally crimped to the first substrate, the first substrate is thermally crimped to the second substrate, and the third substrate is thermally crimped to the covering layer, the second conductor and the third conductor are configured to surround the transmission line conductor and are ultrasonically bonded to each other, and the folded end of the second conductor overlaps with the grounding conductor and is ultrasonically bonded.
[0015] According to this structure, the transmission line conductor is surrounded by the second conductor and the third conductor, so that the desired shielding performance can be obtained. In addition, by combining the thermocompression bonding and ultrasonic bonding of the folded end, a thin structure that can save space can be obtained. As an example, the transmission line conductor is formed at a first interval, and the second conductor is formed with a through hole at a second interval at a position overlapping with the ground conductor when viewed from above.
[0016] The method for manufacturing a transmission line of the present invention manufactures a transmission line having the following structure, wherein the transmission line comprises: a first conductor, which is composed of a transmission line conductor and a pair of grounding conductors, the pair of grounding conductors being close to an input end and an output end of the transmission line conductor, respectively; a first substrate, which is formed with the first conductor; a covering layer, which covers the transmission line conductor; a first shielding member, which is formed with a second conductor on a second substrate; and a second shielding member, which is formed with a third conductor on a third substrate, the covering layer being thermally pressed to the first substrate, the first substrate being thermally pressed to the third substrate, 2 substrates, the third substrate is hot-pressed to the covering layer, the second conductor and the third conductor are arranged to surround the transmission line conductor and are ultrasonically bonded to each other, the transmission line conductor is formed at a first interval, and is characterized in that the end of the second conductor is folded back to overlap with the grounding conductor, the anvil is abutted against the end, and the welding head is pushed from a direction opposite to the anvil so that the welding head abuts against the grounding conductor, the end and the grounding conductor are ultrasonically bonded by using the anvil and the welding head, wherein the cone of the welding head is arranged at a second interval.
[0017] According to this structure, the end of the second conductor and the ground conductor can be reliably ultrasonically joined at the correct position. In addition, by suppressing the overlapping portion of the end of the second conductor and the ground conductor with the anvil, the conductor can be prevented from being stretched during ultrasonic joining. In addition, the thermoplastic resin can be prevented from being unnecessarily extruded during ultrasonic joining, and thermal deformation can be alleviated when the thermoplastic resin heat shrinks after ultrasonic joining. Thus, a transmission line having shielding performance, a thin structure for space saving, and a structure with low transmission loss that can cope with high-speed transmission can be manufactured.
[0018] Effects of the Invention
[0019] According to the transmission line of the present invention, it is possible to realize a transmission line which has shielding performance required for use in electronic equipment, is thin for space saving, and has a structure with low transmission loss capable of high-speed transmission. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a schematic perspective view showing an example of a transmission line according to the present embodiment.
[0021] Figure 2 yes Figure 1 A top view of the transmission line is shown.
[0022] Figure 3 yes Figure 2 A cross-sectional view of the transmission line along line III-III is shown.
[0023] Figure 4 yes Figure 2 A cross-sectional view of the transmission line along line IV-IV is shown.
[0024] Figure 5A is a schematic cross-sectional view showing an ultrasonic bonding structure in a method for manufacturing a transmission line according to the present embodiment, Figure 5B It is shown Figure 5A A schematic perspective view of an example of a first front end portion of Figure 5C It is shown Figure 5A A schematic three-dimensional view of an example of the second front end portion.
[0025] Figure 6 yes Figure 1 Bottom view of the transmission line shown.
[0026] Figure 7 1 is a flowchart showing a manufacturing process of the transmission line according to the present embodiment. DETAILED DESCRIPTION
[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As an example, the transmission line 20 of the present embodiment has two transmission line conductors 32 formed at a first interval P1, and one end portion and the other end portion are symmetrical in shape. Figure 1 2 is a schematic perspective view showing an example of the transmission line 20 , and a region P4 surrounded by a dotted line shows an enlarged view of an end portion of the transmission line 20 . Figure 2 2 is a schematic plan view showing an example of the transmission line 20 , and a region P5 surrounded by a dotted line shows an enlarged view of an end portion of the transmission line 20 . Figure 3 yes Figure 2 Cross-sectional view along line III-III. Figure 4 yes Figure 2 Cross-sectional view along line IV-IV. Figure 6 1 is a schematic bottom view showing an example of the transmission line 20, and a region P6 surrounded by a dotted line shows an enlarged view of an end portion of the transmission line 20. In all the drawings for explaining the embodiments, components having the same function are denoted by the same reference numerals, and duplicate descriptions may be omitted.
[0028] like Figure 1 to Figure 6 As shown, the transmission line 20 is constituted by a flexible multilayer wiring substrate, and the transmission line 20 has: a base 30, which has a first conductor 31 and a first substrate 34, the first conductor 31 is composed of a transmission line conductor 32 and a ground conductor 33, and the first substrate 34 is formed with the first conductor 31; a covering layer 35, which covers the transmission line conductor 32; a first shielding member 40, which has a second conductor 41 formed on a second substrate 42; and a second shielding member 45, which has a third conductor 46 formed on a third substrate 47, the covering layer 35 is thermally compressed to the first substrate 34, the first substrate 34 is thermally compressed to the second substrate 42, and the third substrate 47 is thermally compressed to the covering layer 35, the second conductor 41 and the third conductor 46 are arranged to surround the transmission line conductor 32 and are ultrasonically bonded to each other, and the folded end 41a of the second conductor 41 overlaps with the ground conductor 33 and is ultrasonically bonded. As an example, a connector is installed at the input end of the transmission line conductor 32 and connected to a control circuit, and a connector is installed at the output end of the transmission line conductor 32 and connected to an antenna structure. The control circuit and the antenna structure are signal-connected.
[0029] As an example, the first substrate 34 and the cover layer 35 are made of thermoplastic fluororesin. The second conductor 41 has through holes 41b formed at a second interval P2 at a position overlapping the ground conductor 33 when viewed from above. As an example, the second substrate 42 and the third substrate 47 are made of thermoplastic polyimide resin.
[0030] As an example, a manufacturing device for the transmission line 20 is provided with a first conductor forming machine, an unnecessary region removing machine, a first bonding machine, a thermocompression bonding machine, a second bonding machine, an inspection machine, and a splitting and extracting machine in order from the upstream side, and has a controller for controlling them. The manufacturing device can also apply the techniques of the above-mentioned patent documents 2 to 3.
[0031] Next, a method for manufacturing the transmission line 20 of the present invention will be described below.
[0032] Figure 7 1 is a flowchart showing the manufacturing process of the transmission line 20 of the present embodiment. As an example, the transmission line 20 is manufactured in the order of the first conductor forming step S1, the unnecessary region removing step S2, the first joining step S3, the thermocompression bonding step S4, the second joining step S5, the inspection step S6, and the dividing step S7.
[0033] As an example, the first conductor 31, the second conductor 41, and the third conductor 46 are made of copper or a copper alloy. In the first conductor forming step S1, the double-sided copper-clad substrate is subjected to etching by a subtractive method, and the transmission line conductor 32 and the ground conductor 33 are formed on the first main surface of the first substrate 34, and the conductors are removed from the second main surface of the first substrate 34 to form the base 30. In this way, warping can be prevented and a flat base 30 can be formed. As a method other than the above, the first main surface of the first substrate 34 can be subjected to pattern plating by an additive method to form the transmission line conductor 32 and the ground conductor 33, thereby forming the base 30.
[0034] The transmission line conductors 32 are formed at the first interval P1 in the substrate 30. The first conductor 31 is composed of the transmission line conductors 32 formed in a straight line and the ground conductors 33 close to the input and output ends of the transmission line conductors 32. The substrate 30 has an unnecessary area between the transmission line conductors 32.
[0035] As an example, the first substrate 34 and the cover layer 35 can be selected from tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene (FEP), polytrifluorochloroethylene (PCTFE), tetrafluoroethylene-ethylene copolymer (ETFE), trifluorochloroethylene-ethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF) and other known thermoplastic fluorine resins. As an example, the second substrate 42 and the third substrate 47 are composed of thermoplastic polyimide resin.
[0036] In the unnecessary region removing step S2, the unnecessary region between the transmission line conductors 32 is punched out to form a rectangular through hole using an unnecessary region removing machine while the base 30 and the cover layer 35 are overlapped. In the first joining step S3, the second conductor 41 and the third conductor 46 are ultrasonically joined at the portion of the workpiece where the unnecessary region is removed using a first joining machine.
[0037] In the thermocompression bonding step S4 , the workpieces are thermocompressed together by roller pressing using a thermocompression bonding machine, thereby thermocompressing the cover layer 35 to the first substrate 34 , the first substrate 34 to the second substrate 42 , and the third substrate 47 to the cover layer 35 .
[0038] In the second bonding step S5, the protruding portion of the first shielding member 40 disposed on the bottom surface of the workpiece is folded back to the upper surface of the workpiece so that the folded-back end portion 41a of the second conductor 41 overlaps with the ground conductor 33, and the end portion 41a of the second conductor 41 is ultrasonically bonded to the ground conductor 33 using a second bonding machine. Figure 5A to Figure 5C As shown, when the end 41a of the second conductor 41 is ultrasonically joined to the grounding conductor 33, an anvil 61 is used which abuts the end 41a from above and a horn 62 which abuts the grounding conductor 33 from below opposite to the anvil 61 and has a cone arranged at a second interval P2. The horn 62 is pushed from a direction opposite to the anvil 61 so that the horn 62 abuts the grounding conductor 33, and the end 41a and the grounding conductor 33 are ultrasonically joined using the anvil 61 and the horn 62.
[0039] As an example, the surface of the anvil 61 that contacts the end 41a is provided with a matrix of 0.28mm-pitch truncated pyramids with a tip of 0.1mm×0.1mm and a protrusion angle of 45 degrees. As an example, the welding head 62 is a truncated cone with a tip of 0.1mm in diameter, and is arranged in a row with the second interval P2 set to 1.12mm.
[0040] In the inspection step S6, the transmission line conductor 32 is checked for disconnection and conduction level by contacting the contact pin of the inspection machine with the transmission line conductor 32 and energizing it. In the segmentation step S7, the workpiece is punched out along a predetermined cutting line by a punching blade of the segmentation and extraction machine.
[0041] Next, Example 1 and Example 2 are described below.
[0042] [Example 1]
[0043] In the transmission line 20 of Example 1, the first substrate 34 and the cover layer 35 are made of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA). The transmission line 20 has a total length of 192 mm, a width of 8.8 mm, a thickness of 0.35 mm, and a first interval P1 of 4 mm. The first conductor 31, the second conductor 41, and the third conductor 46 are made of copper and have a thickness of 12 mm. μ The through hole 41 b is formed in a tapered shape in the thickness direction and penetrates the first base material 34 and the cover layer 35 .
[0044] [Example 2]
[0045] In the transmission line 20 of Example 2, the first substrate 34 and the cover layer 35 are made of liquid crystal polymer (LCP). Other than that, the structure is the same as that of Example 1 described above.
[0046] For each sample, a transmission loss at a frequency of 3 GHz and a transmission loss at a frequency of 6 GHz were measured using a network analyzer (N5247A manufactured by Keysight Technologies). The evaluation results are shown in Table 1 below.
[0047] [Table 1]
[0048] Unit: dB
[0049]
[0050] As shown in Table 1, it can be confirmed that the transmission loss of Example 1 is greatly improved compared with that of Example 2. This means that the transmission loss can be improved by using a material with a lower relative dielectric constant in a high-frequency band as the thermoplastic resin constituting the first substrate 34 and the cover layer 35. It also means that the transmission loss can be improved by using a material with a lower dielectric loss tangent in a high-frequency band. In addition, as a reference example, a comparison was made with a coaxial cable combined with the same material, and it was confirmed that the transmission loss was improved by 15%.
[0051] In the above-mentioned embodiment, PFA or LCP is used as the first substrate 34 and the cover layer 35, but it is not limited to this example, and a known thermoplastic resin can be applied. In addition, in the above-mentioned embodiment, the flexible substrate adopts a 4-layer structure, but it is not limited to this example. A multilayer structure of 5 or more layers can be adopted according to the application. In the above-mentioned embodiment, a structure with two transmission line conductors 32 is described, but it is not limited to this example. Sometimes a structure with three or more transmission line conductors 32 is adopted. In addition, a structure with one transmission line conductor 32 can also be adopted. The present invention is not limited to the above-mentioned embodiment, and various changes can be made without departing from the scope of the present invention.
Claims
1. A transmission line, It is characterized in that The transmission line has: a first conductor, which is composed of a transmission line conductor and a pair of ground conductors, the pair of ground conductors being close to an input end and an output end of the transmission line conductor, respectively; a first substrate having the first conductor formed thereon; a cover layer covering the transmission line conductor; a first shield having a second conductor formed on a second substrate; and a second shielding member having a third conductor formed on a third substrate, The cover layer is thermally pressed onto the first substrate, the first substrate is thermally pressed onto the second substrate, and the third substrate is thermally pressed onto the cover layer. The second conductor and the third conductor are arranged to surround the transmission line conductor and are ultrasonically bonded to each other, and a folded-back end portion of the second conductor overlaps with the ground conductor and is ultrasonically bonded to each other.
2. The transmission line according to claim 1, It is characterized in that The transmission line conductor is formed at a first interval, and the second conductor has through holes formed at a second interval at a position overlapping with the ground conductor when viewed from above.
3. The transmission line according to claim 1 or 2, It is characterized in that The first substrate and the cover layer are made of fluororesin.
4. A method for manufacturing a transmission line, manufacturing a transmission line having the following structure, wherein the transmission line comprises: a first conductor, which is composed of a transmission line conductor and a pair of grounding conductors, the pair of grounding conductors being close to an input end and an output end of the transmission line conductor, respectively; a first substrate, which is formed with the first conductor; a covering layer, which covers the transmission line conductor; a first shielding member, which is formed with a second conductor on a second substrate; and a second shielding member, which is formed with a third conductor on a third substrate, the covering layer being thermally pressed to the first substrate, the first substrate being thermally pressed to the second substrate, and the third substrate being thermally pressed to the covering layer, the second conductor and the third conductor being arranged to surround the transmission line conductor and being ultrasonically bonded to each other, the transmission line conductor being formed at a first interval, It is characterized in that The end of the second conductor is folded back to overlap with the grounding conductor, the anvil is brought into contact with the end, and the welding head is pushed from a direction opposite to the anvil to bring the welding head into contact with the grounding conductor, and the end and the grounding conductor are ultrasonically joined using the anvil and the welding head, wherein the cone of the welding head is arranged at a second interval.
5. The method for manufacturing a transmission line according to claim 4, It is characterized in that The first substrate and the cover layer are made of fluororesin.