JP2009245595A - Thin wire cable with shield, and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new thin wire cable with a shield which is excellent on flexibility and a shield property, and to provide a method of manufacturing the same. <P>SOLUTION: The thin wire cable with the shield has a lead wire 2 wherein a plurality of coated thin wires are twisted each other and a shield section wherein the coated thin wires are wound in a coil-shape, and the lead wire 2 is inserted into a coil-shaped shield section 3. Both the coated thin wire used as the lead wire and the coated thin wire used as the shield section have a diameter of ≤0.3 mm, for example, the same coated thin wires. The lead wire 2 is formed by twisting two coated thin wires 2a, 2b at a twisted shape, and the shield section 3 is formed by winding one coated thin wire in a coil shape. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a novel shielded thin wire cable which is rich in flexibility, and further relates to a manufacturing method thereof.

  With the development of ultra-miniaturized mechatronics and precision-driven measuring devices that move, such as scanning probe microscopes (SPM), there is an increasing demand for flexible and lightweight thin wire cables. For example, in the case of the scanning probe microscope, it is necessary to perform cable wiring with respect to the drive unit and the probe with a thin wire having high flexibility.

  This is because the movement of the drive unit is not impaired. Further, when used in a scanning probe microscope, it is necessary to reduce the vibration propagating through the cable, and the cable wiring to be used is required to have good flexibility.

  Under such circumstances, for example, a thin wire having an outer diameter of 1 mm or less is used to reduce the weight and flexibility by thinning the wire to avoid the above-described problems. However, there are also demands for electrostatic shielding, current capacity, etc. depending on the application, and the actual situation is that it is not always possible to cope with the thinning alone. For example, since the scanning probe microscope described above handles minute signals, it is necessary to prevent interference with other wiring, and it is also necessary to provide an electrostatic shield for the cable wiring. It is also desirable that the maximum current that can be passed is as large as possible. Furthermore, in the case of cable wiring of a scanning probe microscope, it is also necessary to be covered and insulated with a resin material that can withstand a high temperature and vacuum environment.

  A so-called coaxial cable is generally used as the electrostatic shielded cable wiring. The coaxial cable uses a silver-plated copper stranded wire as the internal conductor, and the surface is covered with polytetrafluoroethylene, and a large number of silver-plated copper wires are wound around the surface to provide an electrostatic shield. And the outermost periphery is again covered with polytetrafluoroethylene. As the coaxial cable, one having an outer diameter of about 0.61 mm is commercially available as an ultrafine coaxial cable and a cable usable in an ultrahigh vacuum. The test voltage of the commercially available ultrafine coaxial cable is 300V, and the allowable current is about 0.5A.

  Various cable wirings have been proposed for the purpose of eliminating the drawbacks of the coaxial cable (see, for example, Patent Document 1 and Patent Document 2).

  For example, in the shielded electric wire described in Patent Document 1, a spiral tube is provided that is attached to a state in which a long band formed from a highly conductive resin is spirally wound, and the spiral tube is formed into a plurality of electric wires. Winding is used to bind the electric wire group by the spiral tube and to provide a shielding property. By adopting the above configuration, the shielded wire described in Patent Document 1 does not require removal of the sheath when performing ground connection, can be bent easily, and can easily change the number of wires and the color of the outer sheath. In addition, there is an advantage that it is possible to provide a shield function only in a required section in a later process.

The signal transmission cable described in Patent Document 2 includes at least one elongated conductive wire, a dielectric layer provided around the conductive wire, and a conductive shield layer provided around the dielectric layer. In a signal transmission cable, a liquid-permeable jacket spirally wound so as to partially expose the shield layer is provided on the outside of the shield layer. The electrical characteristics are made stable.
JP 2001-3573321 A JP-A-6-139835

  However, in the case of a general coaxial cable, it is difficult to obtain sufficient flexibility even if the wire diameter is reduced. In addition, it is conceivable to bend into a coil shape for the purpose of imparting flexibility, but the restoring force to return to the original shape is strong, and it is difficult to adjust the shape. As the cause, it is mentioned that resin is applied in a tube shape around and around the inner conductor to insulate.

  On the other hand, in the shielded wire described in Patent Document 1 and the signal transmission cable described in Patent Document 2, a strip-shaped sheet (a long strip formed of a highly conductive resin, a plastic tape coated with an aluminum layer, etc.) It is considered that it is easy to bend as compared to a coaxial cable because it has a shielding function by being wound around the (conductor). However, when the belt-like sheet is wound in a spiral shape, the movement is limited due to the belt-like sheet having a certain width, and movement like a shield wiring to a part accompanied by movement of a precision micro device It is difficult to achieve sufficient flexibility so as not to interfere.

  For example, in the signal transmission cable described in Patent Document 2, the shield conductor is wound so as to overlap about 10% in order to make the impedance uniform, but when the band-shaped shield conductors are wound so as to overlap each other, The movement is greatly restricted and it is difficult to obtain the required flexibility. In addition, in the signal transmission cable described in Patent Document 2, a strip-shaped jacket is also wound in addition to the shield conductor, and since it is in a multi-winding state, it is expected to be considerably stiff, and in terms of flexibility It is considered disadvantageous. Furthermore, the signal transmission cable described in Patent Document 2 has a problem that the overlapping portion of the strip-shaped shield conductor and jacket increases, and is not suitable for use under vacuum. This is because it is difficult to quickly escape the remaining gas (air) from the overlapping portion.

  In the shielded wire described in Patent Document 2, there are few overlapping portions, and the above problem in applications under vacuum is reduced. For example, in the specification, since the spiral tube is made of resin and has rigidity, the wiring group is arranged. It can be held in a shape that extends linearly along the path, can be bent at a required position, and can be held in a required form (paragraph 0023), which is less flexible than a coaxial cable. It is considered a thing. In addition, in the shielded wire described in Patent Document 2, since the spiral tube that functions as a shield is formed of a highly conductive resin, it is necessary to cover the insulating tube for insulation, but the covering with the insulating tube is more flexible. It becomes a factor that impairs sex.

  The present invention has been proposed in view of such a conventional situation. For example, the present invention has sufficient flexibility as a shield wiring to a part accompanying movement of a precision microminiature device, and has a sufficient shielding function and tolerance. An object of the present invention is to provide a completely new shielded thin wire cable having a current value, and further to provide a manufacturing method thereof and a scanning probe microscope using the shielded thin wire cable.

  In order to achieve the above object, a shielded thin wire cable according to the present invention has a lead wire in which a plurality of coated thin wires are twisted together, and a shield portion in which the coated thin wires are wound in a coil shape, A lead wire is inserted into the coil-shaped shield portion.

  The method for manufacturing a shielded thin wire cable according to the present invention includes forming a lead wire by twisting a plurality of coated thin wires, and winding a single coated thin wire around a metal rod to form a coiled shield portion. And forming one end of the lead wire at the end of the metal rod, and pulling out the metal rod from the shield portion to insert the lead wire into the coil-shaped shield portion. Furthermore, the scanning probe microscope according to the present invention is characterized in that the above-described shielded thin wire cable is used as a cable wiring for at least one of a drive unit, a sample, and a probe.

  In the shielded thin wire cable of the present invention, the coated thin wire wound in a coil shape works as an electrostatic shield. The shield portion in which the coated thin wire is wound in a coil shape is freely bent by spreading slightly between the coated thin wires, and exhibits sufficient flexibility. In addition, since the lead wire is formed by twisting a plurality of coated thin wires, an allowable current is sufficiently ensured. Furthermore, since there is no closed space sandwiched between the conductor and the insulator, there is no gas pool when evacuating.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the shielded thin wire | line cable which has sufficient flexibility as a shield wiring to the site | part etc. with a motion of a precision microminiature apparatus, and has a sufficient shield function. Moreover, in the shielded thin wire cable of the present invention, the allowable current can be arbitrarily set, and can cope with a large current. Therefore, it is possible to provide a scanning probe microscope with high reliability by using the shielded thin wire cable of the present invention.

  Hereinafter, a shielded thin wire cable to which the present invention is applied, a manufacturing method thereof, and a scanning probe microscope will be described in detail with reference to the drawings.

  As shown in FIG. 1, a shielded thin wire cable 1 of the present invention includes, for example, a lead wire 2 obtained by twisting two coated thin wires 2a and 2b, and a shield portion 3 obtained by winding one coated thin wire in a coil shape. The lead wire 2 is inserted through the central portion of the coil-shaped shield portion 3 and is configured as one thin wire cable.

  The coated thin wires 2a and 2b used for the lead wire 2 and the coated thin wires used for the shield part 3 are all coated thin wires in which an insulating film is formed around the conducting wire. For example, the copper wire is covered with polyimide. A polyimide-coated copper wire or the like can be used. In this case, the copper wire may be a single copper wire or a bundle of a plurality of fine copper wires. However, in consideration of thinning of the shielded thin wire cable 1 and brazing of the shield portion 3 to the coil shape, it is preferable to use one copper wire type.

In addition, the thickness (outer diameter) of the coated thin wires 2a and 2b used for the lead wire 2 and the coated thin wire used for the shield part 3 is arbitrary. For example, the movement of a precision microminiature device such as a scanning probe microscope When the shielded thin wire cable 1 is used as a shield wiring to a portion accompanied by a wire, it is desirable that the thickness of each coated thin wire is as thin as possible. When the thickness of the coated thin wire is increased, the flexibility may be reduced accordingly. Therefore, specifically, it is preferable that the outer diameter of the coated thin wires 2a and 2b used for the lead wire 2 and the coated thin wires used for the shield part 3 is 0.3 mm or less. By setting the outer diameter of the coated thin wire used for the shield part 3 to 0.3 mm or less, it is possible to achieve sufficient flexibility in the shielded thin wire cable 1.

  In addition, when using the shielded thin wire cable 1 for a somewhat large apparatus or the like, the outer diameter of each coated thin wire may be larger than this. Further, the coated thin wires 2a and 2b used for the lead wire 2 and the coated thin wires used for the shield part 3 may be different types of coated thin wires, but the same type (same) coated thin wires should be used. Thus, the flexibility of the lead wire 2 and the shield part 3 can be matched to each other, which is a preferable combination.

  2A shows a state in which the lead wire 2 constituting the shielded thin wire cable 1 is taken out from the shield portion 3, and FIG. 2B shows the shield portion 3 in a state in which the lead wire 2 is taken out. The form is shown. FIG. 3 schematically shows the configuration of the shielded thin wire cable 1 of the present invention, in which (a) shows a state in which the lead wire 2 is taken out from the shield portion 3, and (b) shows the lead wire. 2 shows a state in which 2 is inserted into the shield part 3.

  As shown in FIGS. 2A and 3A, the lead wire 2 is formed by twisting a plurality of (two in this case) coated thin wires 2a and 2b together in a so-called twist shape, (Signal) is supplied. Therefore, the allowable current of the lead wire 2 is determined by the number of coated fine wires to be twisted, the thickness of the conductive wire of each coated fine wire, etc. For example, when a larger allowable current value is required, three or more coated fine wires are twisted. It is also possible to match. However, if the number of coated fine wires to be twisted becomes too large, the flexibility of the lead wire 2 may be reduced, and as a result, the flexibility of the shielded fine wire cable 1 may be reduced. It is desirable to avoid it.

  On the other hand, the shield part 3 is formed by winding one coated thin wire in a coil shape, as shown in FIG. 2 (b) and FIG. 3 (a). By winding the coated thin wire in a coil shape, it is possible to form the shield portion 3 so as to cover the periphery of the lead wire 2. The shield part 3 is preferably formed by winding one coated thin wire as described above, but depending on the case, for example, a plurality of coated thin wires are wound in a coil shape to form the shield part 3. It is also possible.

  Further, when the coated thin wire is wound in a coil shape to form the shield part 3, it may be densely wound in a so-called solenoid shape so that adjacent turns are in contact with each other, that is, the wound coated thin wires are in contact with each other. preferable. A good shielding function can be obtained by densely winding the coated fine wire.

  In the prior art, as described above, it is common to use a belt-like sheet for the shield with an emphasis on the shielding function. However, when the belt-like sheet is wound around the lead wire, the movement is restricted by the belt-like sheet, and sufficient flexibility cannot be obtained. On the other hand, in the shielded thin wire cable 1 of the present invention, the shield portion is formed by winding the coated thin wire as described above, so that sufficient flexibility can be ensured. For example, in the shield part 3 in which one coated thin wire is wound in a coil shape, the coated thin wire itself is soft and has almost no spring property, so that a force to return to bending hardly acts. Therefore, the shielded thin wire cable 1 having a low spring property (a weak force to return to deformation) is realized by forming the shield portion 3 in a coiled shape with dense winding and only by a thin wire. Can do. Further, it has been experimentally confirmed that if the shield portion 3 is formed by densely winding the coated thin wire, the shield characteristic is not deteriorated even if it is soft.

  The shielded thin wire cable 1 having the above-described configuration can be easily manufactured through the following steps. That is, in order to produce the shielded thin wire cable 1, first, the lead wire 2 is prepared by twisting two coated thin wires (for example, polyimide-coated copper wires) in a twisted shape.

  Next, one coated thin wire is prepared, and this is wound around the periphery using a thin metal rod. As the coated thin wire, for example, the same type as the coated thin wire used for the lead wire 2 is used. Thereby, the covering thin wire is wound in a coil shape, and the shield part 3 is formed.

  Thereafter, the prepared lead wire 2 is passed through the shield portion 3 in which the coated thin wire is wound in a coil shape. In order to pass the lead wire 2 through the shield part 3, the metal rod may be used. For example, one end of the lead wire 2 is fixed to the end of the metal bar, and the metal bar is pulled out from the shield part 3. Thereby, the lead wire 2 is inserted into the shield part 3.

  The shielded thin wire cable 1 manufactured as described above can be used as a shield wiring to a portion accompanied by movement of various precision microminiature devices. For example, in a scanning probe microscope, a scanning probe microscope with high reliability can be realized by using it as a shield wiring connected to a drive unit, a sample, a probe, or the like. Since the shielded thin wire cable 1 of the present invention has sufficient flexibility, it can absorb and reduce the vibration propagating through the cable without impairing the movement of the drive unit. Further, a sufficient shielding effect can be obtained, and interference with other wiring can be prevented even when a minute signal is handled. Furthermore, each coated thin wire is coated with a resin that can withstand a high temperature / vacuum environment, and can sufficiently withstand use in a vacuum (reduced pressure) environment. Further, since no gas reservoir is formed, it is optimal for use under ultra-vacuum, for example. Furthermore, the maximum current that can be passed can be increased. These effects are extremely effective in improving the reliability of the scanning probe microscope.

  Hereinafter, specific examples of the present invention will be described based on experimental results.

  In this example, a polyimide-coated copper wire (coated with a polyimide film having a thickness of 20 μm) was used as a thin wire for the lead wire or shield portion. The outer diameter of this polyimide-coated copper wire is about 0.16 mm.

  Using the coated thin wire, a shielded thin wire cable was produced according to the production procedure described above. That is, two coated thin wires are twisted together to form a lead wire, and this is inserted into a coiled shield formed by winding the coated thin wire around a metal rod, so that the outer diameter is about A 0.6 mm shielded thin wire cable was produced.

In the produced shielded thin wire cable, when bent, a gap of the same degree as the coated thin wire was formed in the coiled shield portion, but the coated thin wire used had a thin outer diameter, and 10 ⁶ Hz. The above frequency noise could be cut off.

  Moreover, the coil-shaped shield part was able to be bent freely because the space between the coated fine wires used was slightly expanded. The flexibility was high, and the entire shielded thin wire cable could be bent into a free shape and wrinkled. In the case of the present Example, the winding wrinkle with an outer diameter of about 3 mm could be provided with respect to the outer peripheral diameter of 0.6 mm of the shielded thin wire cable, and it was able to bend to the outer diameter of about 1.5 mm.

  Furthermore, unlike the coaxial cable covered with tetrafluoroethylene, the shielded thin wire cable of the present embodiment has no closed space sandwiched between the copper wire and the insulator, so that the gas pool when the vacuum is applied It was also excellent as a vacuum cable. Moreover, the allowable current value was high, and the test voltage could withstand a current of 300 V and 1 A or more.

It is a schematic perspective view of the shielded thin wire cable to which the present invention is applied. (A) is a schematic perspective view which takes out and shows the lead wire of the shielded thin wire | line cable to which this invention is applied, (b) is a schematic perspective view of a coil-shaped shield part. It is a figure which shows typically the shielded thin wire | line cable to which this invention is applied, (a) shows a decomposition | disassembly state and (b) shows an assembly | attachment state, respectively.

Explanation of symbols

  1 Shielded fine wire cable, 2 Lead wire, 2a, 2b Coated fine wire, 3 Shield part

Claims (10)

  It has a lead wire in which a plurality of coated thin wires are twisted together and a shield part in which the coated thin wire is wound in a coil shape, and the lead wire is inserted into the coiled shield portion. Shielded thin cable.   2. The shielded thin wire cable according to claim 1, wherein the coated thin wire used for the lead wire and the shield portion is a coated copper wire in which the copper wire is coated with an insulating material having plasticity.   The shielded thin wire cable according to claim 2, wherein the insulating material is polyimide.   4. The shielded thin wire cable according to claim 1, wherein an outer diameter of each of the coated thin wires used for the lead wire and the shield portion is 0.3 mm or less. 5.   5. The shielded thin wire cable according to claim 1, wherein the coated thin wire used for the lead wire and the coated thin wire used for the shield portion are equivalent coated thin wires. 6.   The shielded thin wire cable according to any one of claims 1 to 5, wherein the lead wire is formed by twisting two coated thin wires into a twist shape.   The shielded thin wire cable according to any one of claims 1 to 6, wherein the shield portion is formed by winding one coated thin wire in a coil shape.   The shielded thin wire cable according to any one of claims 1 to 7, wherein the shielded thin wire cable is used in a reduced pressure environment. A plurality of coated thin wires are twisted together to form a lead wire, and a coiled shield portion is formed by winding one coated thin wire around the metal rod,
A method of manufacturing a shielded thin wire cable, wherein one end of the lead wire is fixed to an end of the metal rod, and the lead wire is inserted into a coiled shield portion by pulling the metal rod out of the shield portion.   A scanning probe microscope characterized in that the shielded thin wire cable according to any one of claims 1 to 8 is used as a cable wiring for at least one of a drive unit, a sample, and a probe. .

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