Patent Application
20240312672
The present disclosure relates to a differential signal transmission cable.
PTL 1 (Japanese Patent Laying-Open No. 2019-16451) describes a differential signal transmission cable. The differential signal transmission cable described in PTL 1 includes an insulating layer, a pair of signal lines, and an electroless plating layer. The pair of signal lines is buried in the insulating layer. The electroless plating layer is formed on an outer peripheral surface of the insulating layer.
A differential signal transmission cable of the present disclosure includes: an insulating layer that extends along a longitudinal direction of the differential signal transmission cable; a pair of signal lines that extends along the longitudinal direction of the differential signal transmission cable and is buried in the insulating layer; and a shield that exists around an outer peripheral surface of the insulating layer. The differential signal transmission cable of the present disclosure further includes an improvement.
In the differential signal transmission cable described in PTL 1, the outer peripheral surface of the insulating layer is roughened by etching. Thus, an anchor effect between the insulating layer and the electroless plating layer is obtained, so that adhesion between the insulating layer and the electroless plating layer is secured.
However, unevenness exists on the outer peripheral surface of the insulating layer after etching. This unevenness causes degradation of a transmission characteristic in a high frequency region greater than or equal to 30 GHz.
The present disclosure has been made in view of the above-described problems of the prior art. More specifically, the present disclosure provides a differential signal transmission cable having the good transmission characteristic in a high frequency region.
According to the differential signal transmission cable of the present disclosure, the good transmission characteristic can be obtained in the high frequency region.
First, embodiments of the present disclosure will be listed and described.
(1) A differential signal transmission cable according to a first aspect of the present disclosure includes: an insulating layer that extends along a longitudinal direction of the differential signal transmission cable; a pair of signal lines that extends along the longitudinal direction of the differential signal transmission cable and is buried in the insulating layer; a shield that exists around an outer peripheral surface of the insulating layer; and a metal oxide layer that exists between the shield and the insulating layer.
According to the differential signal transmission cable of (1), adhesion between the shield and the insulating layer and a good transmission characteristic in a high frequency region can be obtained.
(2) The differential signal transmission cable of (1) may further include an intermediate layer that covers the outer peripheral surface of the insulating layer. The metal oxide layer may cover the outer peripheral surface of the intermediate layer.
(3) In the differential signal transmission cable of (2), the metal oxide layer may be a copper oxide layer.
(4) The differential signal transmission cable of (2) or (3) may further include a first catalyst particle in the metal oxide layer.
(5) In the differential signal transmission cable of (4), the first catalyst particle may be a particle containing palladium.
(6) In the differential signal transmission cables of (2) to (5), a thickness of the metal oxide layer may be smaller than a thickness of the intermediate layer in the section orthogonal to the longitudinal direction of the differential signal transmission cable.
(7) In the differential signal transmission cables of (2) to (6), in the section orthogonal to the longitudinal direction of the differential signal transmission cable, the thickness of the metal oxide layer may be greater than or equal to 0.001 times and less than or equal to 0.9 times the thickness of the intermediate layer.
(8) In the differential signal transmission cables of (2) to (7), the thickness of the metal oxide layer may be greater than or equal to 1.5 nm and less than or equal to 223 nm in the section orthogonal to the longitudinal direction of the differential signal transmission cable.
(9) In the differential signal transmission cables of (2) to (8), the metal oxide layer may have a first surface facing an intermediate layer side and a second surface facing a shield side in the section orthogonal to the longitudinal direction of the differential signal transmission cable. The first surface may include a first recess recessed toward a second surface side and a first protrusion protruding to the side opposite to the second surface in the section orthogonal to the longitudinal direction of the differential signal transmission cable.
(10) In the differential signal transmission cable of (9), the second surface may include a second recess recessed toward a first surface side and a second protrusion protruding to a side opposite to the first surface in the section orthogonal to the longitudinal direction of the differential signal transmission cable.
(11) In the differential signal transmission cables of (2) to (8), the thickness of the metal oxide layer may vary along the outer peripheral surface of the intermediate layer in the section orthogonal to the longitudinal direction of the differential signal transmission cable.
(12) In the differential signal transmission cables of (2) to (11), the metal oxide layer may cover the outer peripheral surface of the intermediate layer over an entire circumference in the section orthogonal to the longitudinal direction of the differential signal transmission cable.
(13) In the differential signal transmission cables of (2) to (11), the intermediate layer and the shield may be partially in contact with each other in the section orthogonal to the longitudinal direction of the differential signal transmission cable.
(14) In the differential signal transmission cables of (2) to (13), the intermediate layer may contain polyolefin.
(15) In the differential signal transmission cables of (2) to (13), the intermediate layer may contain an acrylonitrile butadiene styrene resin.
(16) The differential signal transmission cables of (2) to (15) may further include a second catalyst particle that exists on the intermediate layer.
(17) In the differential signal transmission cable of (16), the second catalyst particle may be a particle containing palladium.
(18) In the differential signal transmission cables of (1) to (17), the shield may include a plating layer.
(19) In the differential signal transmission cable of (18), the plating layer may be in contact with the metal oxide layer.
(20) In the differential signal transmission cable of (18) or (19), the plating layer may include an electroless plating layer.
(21) In the differential signal transmission cable of (20), the electroless plating layer may be in contact with the metal oxide layer.
(22) In the differential signal transmission cable of (21), adhesive strength between the electroless plating layer and the metal oxide layer may be greater than or equal to 0.1 N/cm and less than or equal to 20 N/cm.
(23) In the differential signal transmission cables of (20) to (22), the plating layer may include an electrolytic plating layer.
(24) In the differential signal transmission cable of (23), the electrolytic plating layer may be formed on the electroless plating layer.
(25) In the differential signal transmission cables of (1) to (24), pull-out strength of each of the pair of signal lines from the insulating layer may be greater than or equal to 0.8 N and less than or equal to 82.5 N.
(26) In the differential signal transmission cables of (1) to (25), arithmetic average roughness of an outer peripheral surface of each of the pair of signal lines may be greater than or equal to 0.009 μm and less than or equal to 0.54 μm.
(27) In the differential signal transmission cables of (1) to (26), in the section orthogonal to the longitudinal direction of the differential signal transmission cable, the insulating layer may include a first portion that is a portion at a distance of up to 50 μm from the outer peripheral surface of each of the pair of signal lines and a second portion that is a portion at a distance of up to 50 μm from the outer peripheral surface of the insulating layer. Hardness of the second portion may be smaller than hardness of the first portion.
(28) In the differential signal transmission cable of (27), the hardness of the first portion may be greater than or equal to 0.02 GPa and less than or equal to 0.11 GPa.
(29) In the differential signal transmission cable of (27) or (28), the hardness of the second portion may be greater than or equal to 0.01 GPa and less than or equal to 0.10 GPa.
(30) In the differential signal transmission cables of (1) to (29), the insulating layer may contain at least one of polyethylene, a cyclic olefin polymer, polymethylpentene, and polypropylene.
(31) In the differential signal transmission cables of (1) to (29), the insulating layer may contain polyolefin having a melting point greater than or equal to 120° C.
(32) In the differential signal transmission cables of (1) to (29), the insulating layer may be a foamed resin layer.
(33) In the differential signal transmission cables of (1) to (32), the pair of signal lines may be a first signal line and a second signal line. In the section orthogonal to the longitudinal direction of the differential signal transmission cable, the insulating layer may include a third portion in which the first signal line is buried and a fourth portion in which the second signal line is buried.
(34) In the differential signal transmission cable of (33), in the section orthogonal to the longitudinal direction of the differential signal transmission cable, a width of the insulating layer in a first direction may be larger than a width of the insulating layer in a second direction orthogonal to the first direction.
(35) In the differential signal transmission cable of (34), the third portion and the fourth portion may be arranged along the first direction.
(36) In the differential signal transmission cable of (35), the insulating layer may further include a fifth portion that exists between the third portion and the fourth portion in the first direction and is integrally formed with the third portion and the fourth portion.
(37) In the differential signal transmission cable of (36), a width of the fifth portion in the second direction may be smaller than a width of the third portion in the second direction and a width of the fourth portion in the second direction.
(38) The differential signal transmission cables of (1) to (3) may further include a first catalyst particle that exists in the metal oxide layer; and a second catalyst particle that exists on the intermediate layer. A total content of the first catalyst particle and the second catalyst particle contained in the differential signal transmission cable may be greater than or equal to 0.1 μg and less than or equal to 10 μg per 1 cm along the longitudinal direction.
(39) A differential signal transmission cable according to a second aspect of the present disclosure includes: an insulating layer that extends along a longitudinal direction of the differential signal transmission cable; a pair of signal lines that extends along the longitudinal direction of the differential signal transmission cable and is buried in the insulating layer; and a shield that exists around an outer peripheral surface of the insulating layer. Pull-out strength of each of the pair of signal lines from the insulating layer is greater than or equal to 0.8 N and less than or equal to 82.5 N.
According to the differential signal transmission cable of (39), adhesion between the shield and the insulating layer and a good transmission characteristic in a high frequency region can be obtained.
(40) A differential signal transmission cable according to a second aspect of the present disclosure includes: an insulating layer that extends along a longitudinal direction of the differential signal transmission cable; a pair of signal lines that extends along the longitudinal direction of the differential signal transmission cable and is buried in the insulating layer; and a shield that exists around an outer peripheral surface of the insulating layer. In a section orthogonal to the longitudinal direction of the differential signal transmission cable, the insulating layer includes a first portion that is a portion at a distance of up to 50 μm from an outer peripheral surface of each of the pair of signal lines and a second portion that is a portion at a distance of up to 50 μm from an outer peripheral surface of the insulating layer. Hardness of the second portion is smaller than hardness of the first portion.
According to the differential signal transmission cable of (40), peeling of the insulating layer from the signal line can be prevented when the differential signal transmission cable is bent.
With reference to the drawings, the embodiment of the present disclosure will be described in detail. In the following drawings, the same or corresponding component is designated by the same reference numeral, and the overlapping description will be omitted.
Hereinafter, a differential signal transmission cable (referred to as a “cable 100”) of the embodiment will be described.
Insulating layer 10 extends along the longitudinal direction of cable 100. Insulating layer 10 is formed of an electrically insulating material. Insulating layer 10 may be formed of a foamed resin. That is, insulating layer 10 may be a foamed resin layer. For example, a thickness of insulating layer 10 (a distance between an outer peripheral surface 10a described later and an outer peripheral surface of signal line 20a or signal line 20b) is greater than or equal to 110 μm and less than or equal to 560 μm. However, the thickness of insulating layer 10 is not limited thereto.
For example, insulating layer 10 is formed of polyethylene, a cyclic olefin polymer, polymethylpentene, or polypropylene. Insulating layer 10 may be a layer containing one or a plurality of these materials. When polyolefin is used for insulating layer 10, the melting point of the polyolefin is preferably greater than or equal to 120° C. from the viewpoint of heat resistance.
Insulating layer 10 includes outer peripheral surface 10a. Insulating layer 10 includes a first portion 11 and a second portion 12. First portion 11 is a portion where the distance from the outer peripheral surface of signal line 20a (signal line 20b) is up to 50 μm. Second portion 12 is a portion having the distance of up to 50 μm from outer peripheral surface 10a. Hardness of second portion 12 is preferably less than hardness of first portion 11. For example, the hardness of first portion 11 is greater than or equal to 0.02 GPa and less than or equal to 0.11 GPa. The hardness of second portion 12 is greater than or equal to 0.01 GPa and less than or equal to 0.10 GPa.
The hardness of first portion 11 may be greater than or equal to 1.03 times the hardness of second portion 12. The hardness of first portion 11 may be greater than or equal to 1.10 times the hardness of second portion 12. The hardness of first portion 11 may be less than or equal to 1.50 times the hardness of second portion 12. The hardness of first portion 11 may be less than or equal to 2.00 times the hardness of second portion 12.
The hardness of first portion 11 may be greater than or equal to 1.03 times and less than or equal to 1.50 times the hardness of second portion 12. The hardness of first portion 11 may be greater than or equal to 1.03 times and less than or equal to 2.00 times the hardness of second portion 12. The hardness of first portion 11 may be greater than or equal to 1.10 times and less than or equal to 1.50 times the hardness of second portion 12.
When insulating layer 10 is made of polyethylene, for example, the hardness of first portion 11 is greater than or equal to 0.024 GPa. In this case, the hardness of first portion 11 may be greater than or equal to 0.024 GPa and less than or equal to 0.030 GPa.
When insulating layer 10 is made of polyethylene, for example, the hardness of second portion 12 is less than or equal to 0.024 GPa. In this case, the hardness of second portion 12 may be greater than or equal to 0.021 GPa and less than or equal to 0.024 GPa.
When insulating layer 10 is made of polypropylene, for example, the hardness of first portion 11 is greater than or equal to 0.060 GPa. In this case, the hardness of first portion 11 may be greater than or equal to 0.060 GPa and less than or equal to 0.090 GPa.
When insulating layer 10 is made of polypropylene, for example, the hardness of second portion 12 is less than or equal to 0.060 GPa. In this case, the hardness of the second portion 12 may be greater than or equal to 0.045 GPa and less than or equal to 0.060 GPa.
Cable 100 has a first direction DR1 and a second direction DR2. First direction DR1 is orthogonal to the longitudinal direction of cable 100. Second direction DR2 is orthogonal to the longitudinal direction of cable 100 and is orthogonal to first direction DR1. Insulating layer 10 has a width W1 along first direction DR1 and a width W2 along second direction DR2. For example, width W1 is larger than width W2.
The hardness in first portion 11 and second portion 12 is measured using a tripoindenter Hysitron TI 980 manufactured by Bruker Corporation. In this measurement, a Berkovich indenter is used as an indenter. A maximum load is 8 mN. A loading time is 5 seconds. A maximum load holding time is 0 seconds. This measurement is performed at 25° C. in the atmosphere.
Signal line 20a and signal line 20b form a pair. A signal having a phase opposite to that of the signal applied to signal line 20a is applied to signal line 20b. Thus, a differential signal is transmitted through cable 100.
Signal line 20a and signal line 20b are buried in insulating layer 10. Signal line 20a and signal line 20b extend along the longitudinal direction of cable 100. Signal line 20a and signal line 20b are formed of a conductive material. For example, signal line 20a and signal line 20b are formed of copper (Cu). However, the material configuring signal line 20a and signal line 20b is not limited to copper. For example, signal line 20a and signal line 20b are arranged along first direction DR1.
Arithmetic average roughness of the outer peripheral surfaces of signal line 20a and signal line 20b is preferably greater than or equal to 0.009 μm and less than or equal to 0.54 μm. The arithmetic average roughness of the outer peripheral surfaces of signal line 20a and signal line 20b is controlled by the arithmetic average roughness of the inner peripheral surface of a metal mold used when signal line 20a and signal line 20b are drawn. The arithmetic average roughness of the outer peripheral surface of signal line 20a (signal line 20b) is measured by a laser microscope VM-X150 (manufactured by KEYENCE CORPORATION). More specifically, the outer peripheral surface of signal line 20a (signal line 20b) is observed using a 50-times objective lens, and the analysis software VK-H1XM is applied to the observation result, whereby the arithmetic average roughness on the outer peripheral surface of signal line 20a (signal line 20b) is calculated.
The pull-out strength during pulling out signal line 20a (signal line 20b) from insulating layer 10 is preferably greater than or equal to 0.8 N and less than or equal to 82.5 N. The pull-out strength during pulling out signal line 20a (signal line 20b) from insulating layer 10 is measured by the following method.
First, a test piece 300 is prepared.
Second, insulating layer 10 at the end of test piece 300 is removed.
Third, signal line 20a is drawn out.
Fourth, signal line 20a is extracted from insulating layer 10.
Intermediate layer 30 covers outer peripheral surface 10a. Intermediate layer 30 includes outer peripheral surface 30a. Intermediate layer 30 is formed of an electrically insulating material. For example, intermediate layer 30 is formed of polyolefin. Intermediate layer 30 may be formed of acrylonitrile butadiene styrene resin (ABS resin). The thickness of intermediate layer 30 depends on an amount of the electrically insulating material configuring intermediate layer 30 applied onto insulating layer 10.
Metal oxide layer 40 is a layer of metal oxide. For example, the metal oxide is copper oxide (CuO). However, the metal oxide is not limited to copper oxide. Metal oxide layer 40 covers outer peripheral surface 30a. Metal oxide layer 40 preferably covers outer peripheral surface 30a over the entire circumference. However, metal oxide layer 40 may not cover a part of outer peripheral surface 30a. In this case, the part of outer peripheral surface 30a is in contact with shield 50.
Metal oxide layer 40 includes a first surface 40a and a second surface 40b opposite to first surface 40a. First surface 40a is a surface facing the side of intermediate layer 30. Second surface 40b is a surface facing the side of shield 50. Metal oxide layer 40 is in contact with intermediate layer 30 on first surface 40a, and is in contact with shield 50 on second surface 40b.
In a section orthogonal to the longitudinal direction of cable 100, first surface 40a may have an irregular shape. That is, first surface 40a includes a plurality of recesses 40aa and a plurality of protrusions 40ab. First surface 40a is recessed toward the side of second surface 40b in recess 40aa, and protrudes to the side opposite to second surface 40b in protrusion 40ab.
In the section orthogonal to the longitudinal direction of cable 100, second surface 40b may have an irregular shape. That is, second surface 40b includes a plurality of recesses 40ba and a plurality of protrusions 40bb. Second surface 40b is recessed toward the side of first surface 40a in recess 40ba, and protrudes toward the side opposite to first surface 40a in protrusion 40bb.
In the section orthogonal to the longitudinal direction of cable 100, a thickness T2 of metal oxide layer 40 is preferably smaller than a thickness T1 of intermediate layer 30. Thickness T2 is preferably greater than or equal to 0.001 times thickness T1 and less than or equal to 0.9 times thickness T1. For example, thickness T1 is greater than or equal to 200 nm and less than or equal to 1000 nm. However, thickness T1 is not limited thereto. For example, thickness T2 is greater than or equal to 1.5 nm and greater than or equal to 223 nm. Thickness T2 is preferably greater than or equal to 2.9 nm and less than or equal to 130 nm. However, thickness T2 is not limited thereto.
Shield 50 covers second surface 40b. That is, shield 50 is located around the outer peripheral surface 10a with intermediate layer 30 and metal oxide layer 40 interposed therebetween. Metal oxide layer 40 is between insulating layer 10 and shield 50. Metal oxide layer 40 is between intermediate layer 30 and shield 50. Shield 50 has conductivity.
For example, shield 50 is a copper layer 51. Copper layer 51 is a layer formed by plating. For example, copper layer 51 includes a first copper layer 52 formed by electroless plating. Copper layer 51 may further include a second copper layer 53 formed by electrolytic plating.
For example, first copper layer 52 is an electroless copper plating layer. First copper layer 52 is in contact with metal oxide layer 40. For example, second copper layer 53 is an electrolytic copper plating layer. Second copper layer 53 is formed on first copper layer 52.
Catalyst particle 60a exists in metal oxide layer 40. The surface of catalyst particle 60a is covered with metal oxide layer 40. Catalyst particle 60b exists on outer peripheral surface 30a. The surface of catalyst particle 60b is partially in contact with outer peripheral surface 30a, and is partially in contact with first surface 40a.
For example, catalyst particle 60a and catalyst particle 60b are particles containing palladium (Pd). However, catalyst particle 60a and catalyst particle 60b are not limited to the particles containing palladium. For example, catalyst particle 60a and the catalyst particle 60b may be particles containing copper, silver (Ag), gold (Au), or the like. Catalyst particle 60a and catalyst particle 60b may contain different materials or contain the same material.
The total content of catalyst particle 60a and catalyst particle 60b included in cable 100 is preferably greater than or equal to 0.1 μg per 1 cm and less than or equal to 10 μg per 1 cm along the longitudinal direction of cable 100. The total content of catalyst particle 60a and catalyst particle 60b per 1 cm along the longitudinal direction of cable 100 is measured using an inductively coupled plasma mass spectrometer.
After preparation process S1, intermediate layer forming process S2 is performed. After intermediate layer forming process S2, heat treatment process S3 is performed. After heat treatment process S3, catalyst particle disposing process S4 is performed. After catalyst particle disposing process S4, oxide layer forming process S5 is performed. After oxide layer forming process S5, electroless plating process S6 is performed. After electroless plating process S6, electrolytic plating process S7 is performed.
In preparation process S1, a processing target member 100A is prepared.
In heat treatment process S3, processing target member 100A on which intermediate layer 30 is formed is subjected to a heat treatment at a predetermined temperature for a predetermined time. For example, the predetermined temperature is greater than or equal to 80° C. and less than or equal to 120° C. For example, the predetermined time is greater than or equal to 1 minute and less than or equal to 30 minutes. In processing target member 100A after heat treatment process S3 is performed, the hardness of second portion 12 is smaller than the hardness of first portion 11.
In oxide layer forming process S5, first, processing target member 100A is immersed in a plating solution in which the material contained in first copper layer 52 is dissolved and a gas containing oxygen (for example, air) is bubbled. Thus, metal oxide layer 40 is formed so as to cover outer peripheral surface 30a with catalyst particles 60 as nuclei. In catalyst particles 60, catalyst particle 60a is a nucleus of growth of metal oxide layer 40, and catalyst particle 60b is another catalyst particle.
In electroless plating process S6, the bubbling is stopped. As a result, first copper layer 52 is plated on metal oxide layer 40.
In electrolytic plating process S7, second copper layer 53 is formed so as to cover first copper layer 52. In electrolytic plating process S7, processing target member 100A is immersed in a plating solution in which the material contained in second copper layer 53 is dissolved, and first copper layer 52 is energized. Thus, second copper layer 53 is plated on first copper layer 52, and cable 100 having the structure in
In cable 100, a hydrogen bond is generated between metal oxide layer 40 and shield 50 (more specifically, first copper layer 52). This hydrogen bonding secures adhesion between metal oxide layer 40 and shield 50, and as a result, adhesion between insulating layer 10 and shield 50 is secured.
As described above, because shield 50 is in close contact with insulating layer 10 with metal oxide layer 40 interposed therebetween, in cable 100, the insertion loss in the high frequency region is hardly degraded due to the roughening of outer peripheral surface 10a. Accordingly, cable 100 has the good transmission characteristic in the high frequency region.
In cable 100, the hardness of second portion 12 is smaller than the hardness of first portion 11. Thus, sectional second moment of insulating layer 10 is reduced, and the deformation of cable 100 easily follows the deformation of insulating layer 10. For this reason, in this case, when cable 100 is bent, insulating layer 10 is hardly peeled off from signal line 20a (signal line 20b).
As the arithmetic average roughness on the outer peripheral surface of signal line 20a (signal line 20b) increases, the adhesion between signal line 20a (signal line 20b) and insulating layer 10 is improved. However, this high adhesion results in degradation of an attenuation characteristic in the high frequency region of cable 100. When the arithmetic average roughness of the outer peripheral surface of the signal line 20a (signal line 20b) is set to greater than or equal to 0.01 μm and less than or equal to 0.25 μm, the attenuation characteristic in the high frequency region of cable 100 can be maintained while the pull-out strength is secured when signal line 20a (signal line 20b) is pulled out from insulating layer 10 (more specifically, greater than or equal to 0.8 N and less than or equal to 82.5 N).
In the section orthogonal to the longitudinal direction of cable 100, when second surface 40b has an irregular shape (that is, second surface 40b includes recess 40ba and protrusion 40bb), the contact area between metal oxide layer 40 and shield 50 increases. Consequently, in this case, the hydrogen bond more strongly acts, and the adhesion of shield 50 can be further secured.
As illustrated in
Signal line 20a and signal line 20b are buried in third portion 13 and fourth portion 14, respectively. Third portion 13, fourth portion 14, and fifth portion 15 are arranged along first direction DR1. Fifth portion 15 is disposed between third portion 13 and fourth portion 14 in first direction DR1. Fifth portion 15 is formed integrally with third portion 13 and fourth portion 14.
A width W3 of third portion 13 in second direction DR2 and a width W4 of fourth portion 14 in second direction DR2 are larger than a width W5 of fifth portion 15 in second direction DR2. From another point of view, outer peripheral surface 10a includes a pair of notches opposite to each other in second direction DR2 between third portion 13 and fourth portion 14.
Cable 100 may not have intermediate layer 30. When cable 100 does not include intermediate layer 30, intermediate layer forming process S2 is omitted. In this case, metal oxide layer 40 directly covers outer peripheral surface 10a.
In the example of the method of manufacturing cable 100 in
In order to evaluate the adhesion between shield 50 and insulating layer 10, Samples 1-1 to 1-10 of cable 100 were prepared. As illustrated in Table 1, in Samples 1-1 to 1-10, the material configuring insulating layer 10, the presence or absence of intermediate layer 30, the processing time in oxide layer forming process S5, the type of gas used for bubbling in oxide layer forming process S5, and the thickness of metal oxide layer 40 were changed.
Adhesion between shield 50 and insulating layer 10 was evaluated by performing a tape peeling test after the bending of cable 100.
“A” in the column of “adhesion between shield 50 and insulating layer 10” in Table 1 indicates that the peeling was not generated in shield 50 in the tape peeling test after the bending was performed using columnar member 500 having a diameter of 100 mm. “B” in the column of “adhesion between the shield 50 and the insulating layer 10” in Table 1 indicates that the peeling was not generated in shield 50 in the tape peeling test after the bending was performed using columnar member 500 having the diameter of 200 mm, but the peeling was generated in shield 50 in the tape peeling test after the bending was performed using columnar member 500 having the diameter of 100 mm.
“C” in the column of “adhesion between shield 50 and insulating layer 10” in Table 1 indicates that the peeling was not generated in shield 50 in the tape peeling test after the bending was performed using columnar member 500 having the diameter of 300 mm, but the peeling was generated in shield 50 in the tape peeling test after the bending was performed using columnar member 500 having the diameter of 200 mm. From these, the adhesion between shield 50 and insulating layer 10 is the lowest when the column of “adhesion between shield 50 and insulating layer 10” in Table 1 is “C”, and the adhesion between shield 50 and insulating layer 10 is the highest when the column of “adhesion between shield 50 and insulating layer 10” in Table 1 is “A”.
As illustrated in Table 1, in Sample 1-1 and Sample 1-8, the evaluation of the adhesion between shield 50 and insulating layer 10 was C. On the other hand, in Samples 1-2 to 1-7, Sample 1-9, and Sample 1-10, the evaluation of the adhesion between shield 50 and insulating layer 10 was greater than or equal to B.
In Sample 1-1 and Sample 1-8, metal oxide layer 40 was not formed. On the other hand, in Samples 1-2 to 1-7, Sample 1-9, and Sample 1-10, metal oxide layer 40 was formed. From this comparison, it was clarified that the adhesion between shield 50 and insulating layer 10 was enhanced by cable 100 including metal oxide layer 40.
In Samples 1-2 and 1-7, the thickness of metal oxide layer 40 was not within the range greater than or equal to 2.9 nm and less than or equal to 130 nm. On the other hand, in Samples 1-3 to 1-6, Sample 1-9, and Sample 1-10, the thickness of metal oxide layer 40 was in the range greater than or equal to 2.9 nm and less than or equal to 130 nm. From this comparison, it was clarified that the adhesion between shield 50 and insulating layer 10 is further enhanced by setting the thickness of metal oxide layer 40 to greater than or equal to 2.9 nm and less than or equal to 130 nm.
In order to evaluate flexibility of insulating layer 10, Samples 2-1 to 2-9 of cable 100 were prepared. As illustrated in Table 2, in Samples 2-1 to 2-9, the material configuring insulating layer 10, the presence or absence of intermediate layer 30, the time for performing heat treatment process S3, and the temperature for performing heat treatment process S3 were changed. As a result, in Samples 2-1 to 2-9, the hardness in first portion 11 and the hardness in second portion changed.
The flexibility of insulating layer 10 was evaluated by performing a cable bending test on cable 100. In the cable bending test, first, cable 100 is bent. The bending is performed by the method illustrated in
“A” in the column of “cable bending test result” in Table 2 indicates that the gap does not exist between insulating layer 10 and signal line 20a (signal line 20b) in bent unit 110 after the bending. “B” in the column of “cable bending test result” in Table 2 indicates that the gap exists between insulating layer 10 and signal line 20a (signal line 20b) in bent unit 110 after the bending.
“C” in the column of “cable bending test result” in Table 2 indicates that the insulating layer 10 was deformed before the bending. Accordingly, the cable bending test was not performed on Sample 2-8 in which the column of “cable bending test result” in Table 2 is “C”.
As illustrated in Table 2, in Sample 2-1, the result of the cable bending test was B. On the other hand, in Sample 2-2 to Sample 2-7 and Sample 2-9, the result of the cable bending test was A.
In Sample 2-1, the hardness in second portion 12 was not smaller than the hardness in first portion 11. On the other hand, in Samples 2-2 to 2-7 and Sample 2-9, the hardness of second portion 12 was smaller than the hardness of first portion 11. From this comparison, it was clarified that because the hardness of second portion 12 is smaller than the hardness of first portion 11, the flexibility of insulating layer 10 is enhanced, and the peeling is hardly generated between insulating layer 10 and signal line 20a (signal line 20b).
Samples 3-1 to 3-8 of cable 100 were prepared in order to evaluate the relationship between the pull-out strength and the insertion loss when signal line 20a in cable 100 is pulled out from insulating layer 10. As illustrated in Table 3, in Samples 3-1 to 3-8, the arithmetic average roughness of signal line 20a, the material configuring insulating layer 10, and the pull-out strength when signal line 20a was pulled out from insulating layer 10 were changed.
“A” in the column of “evaluation” in Table 3 indicates that the insertion loss was less than or equal to −25 dB/m, and the insertion loss was not degraded by the applied twist. “B” in the column of “evaluation” in Table 3 indicates that the insertion loss was greater than −25 dB/m, and the insertion loss was degraded by the applied twist.
As illustrated in Table 3, the evaluation of the insertion loss for Sample 3-1 and Sample 3-7 was B. On the other hand, the evaluation of the insertion loss for Sample 3-2 to Sample 3-6 and Sample 3-8 was A.
In Samples 3-1 and 3-7, the pull-out strength in pulling out signal line 20a from insulating layer 10 was not within the range greater than or equal to 0.8 N and less than or equal to 82.5 N. On the other hand, in Samples 3-2 to 3-6 and Sample 3-8, the pull-out strength in pulling out signal line 20a from insulating layer 10 was in the range greater than or equal to 0.8 N and less than or equal to 82.5 N. From this comparison, it was clarified that the degradation of the insertion loss of cable 100 can be prevented by setting the pull-out strength in pulling out signal line 20a (signal line 20b) from insulating layer 10 to greater than or equal to 0.8 N and less than or equal to 82.5 N.
It should be understood that the embodiments disclosed herein is illustrative in all respects and are not restrictive. The scope of the present invention is defined not by the embodiment but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/006167 | 2/18/2021 | WO |
