JP2003139794A - Multi-terminal structure for measuring impedance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-terminal structure for measuring the impedance capable of coping with a narrow measured part, and exercising the characteristic of high strength. SOLUTION: A flexible shaft body 11 is formed by twisting two conductive metallic wires 14, 14 respectively coated with insulating layers 22, a tip part 12 of the flexible shaft body 11 is formed as an independent contact end 15 for the measured part, by respectively exposing a tip of each metallic fine wire 14 from the insulating layer 22 while keeping the mutually insulated- condition, and a rear end part 13 is formed as a connection end 16 for a lead wire 31, by respectively exposing a rear end face 14a of each metallic wire 14 from the insulating layer 22 while keeping the mutually insulated-condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to make contact with a narrow measurement site even with a multi-terminal such as a four-terminal measurement probe provided in a substrate inspection machine such as an in-circuit tester. This is a technique relating to a multi-terminal structure for impedance measurement that can exhibit excellent characteristics in strength.

[0002]

2. Description of the Related Art One of the multi-terminal impedance measuring methods is a four-terminal measuring method. This measurement method prepares a pair of constant current terminals for flowing a current through the object to be measured, which is a resistor, and a pair of voltage detection terminals for detecting the voltage drop state at that time, and these terminals are connected to these terminals. It is performed using a total of four lead wires connected to each.

Further, in the four-terminal measuring method performed in this way, the resistance of the lead wire can be measured without including it in the measured value, so that a highly accurate resistance measuring device such as a digital multimeter or an LCR meter can be used. Has been adopted by many.

FIGS. 3 and 4 show an example of the structure of a contact probe that has been conventionally used to support the above-mentioned four-terminal measuring method.

Of these, the contact probe shown in FIG. 3 is of the so-called parallel type,
The whole has a voltage measuring probe 1 in which a plunger 1b having a voltage measuring pin 1a at its tip is held in the barrel 1c by freely urging it forward and backward, and a current measuring pin 2a at its tip. A current measuring probe 2 which holds the plunger 2b in the barrel 2c by freely urging the plunger 2b forward and backward, and a sleeve 4 which integrally holds these probes 1 and 2 with an insulator 3 interposed therebetween. It is formed by.

Further, the contact probe shown in FIG.
It is a so-called coaxial type, and its entirety is for voltage measurement in which a plunger 5b having a voltage measuring pin 5a at its tip is urged and held freely in a barrel 5c to advance and retract. A current measuring probe 7 including a probe 5 and a current measuring pin 7a arranged so as to surround the periphery of the probe 5 by arranging the voltage measuring probe 5 at the center of an axis with an insulator 6 interposed; The current measuring probe 7 is formed of a sleeve 9 which holds the current measuring probe 7 so as to be movable back and forth in the axial direction by a spring member 8 which is interposed between the current measuring probe 7 and the current measuring probe 7.

[0007]

By the way, FIG. 3 and FIG.
Although it is possible to measure an object to be measured by the four-terminal measurement method using any of the contact probes shown in 1) and 2), all of them have a structurally complicated structure, which disadvantageously increases the product cost.

Further, in the contact probes shown in FIGS. 3 and 4, the distance between the voltage measuring pin 1a or 5a and the current measuring pin 2a or 7a is relatively large, so that the contacted surface is relatively large. Although it is possible to deal with the case where it is wide, there is a problem that it cannot be used when the contacted surface is narrow.

Moreover, when the contact probe is made to have a small diameter in order to cope with a narrow contact surface, the distance between the pins can be made relatively short, but the pins themselves are also very thin. Weakened in strength,
As a result, there is also a problem that the durability is lowered and it cannot be put to practical use.

In view of the above-mentioned problems that have been observed in conventional contact probes, the present invention makes it possible to cope with a narrow measurement site and to perform impedance measurement capable of exhibiting excellent strength characteristics. It is intended to provide a multi-terminal structure for a vehicle.

[0011]

The present invention has been made to achieve the above object, and it is possible to twist two or more conductive thin metal wires, each surface of which is covered with an insulating layer. A flexible shaft-like body is formed, and at least one end portion of the flexible shaft-like body in the longitudinal direction is exposed at one end thereof from the insulating layer while maintaining a mutually insulated state. To form an independent contact end for the measured part, and at the other end, expose the other end of each thin metal wire from the insulating layer while maintaining a mutual insulation state, and connect for the lead wire. There are structural features in forming the edges.

In this case, each of the contact ends is preferably sharpened. In addition, the insulating layer,
It can be formed of any of an insulating resin tube, an insulating coating film, and an insulating coating film. Further, the flexible shaft-like body may be housed and held in at least a portion excluding the contact end in a highly flexible insulating tubular material.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the present invention, in which (a) is an enlarged front view with a part omitted, and (b) is a view taken along the line AA in (a). A cross-sectional view in the direction, and (c) is a bottom view (front end side) of (a). According to these figures, two conductive metal wires 14, 14 each surface of which is covered with the insulating layer 22 are shown.
A flexible shaft-shaped body 11 formed by closely twisting each other is formed.

Among them, the thin metal wire 14 having an appropriate wire diameter can be formed by using an appropriate conductive material such as copper or high speed tool steel (high speed steel), and its length can be appropriately selected according to the application. You can

Further, the insulating layer 2 covering the peripheral surface of the thin metal wire 14
2 can be formed by an insulation coating film obtained by baking an insulation resin such as a fluororesin or an applied insulation coating film, and a tube material such as a heat-shrinkable tube made of an insulating synthetic resin is covered. It can also be formed by

Further, the flexible shaft 11 has a tip end 12 which is one end thereof as a contact side to the site to be measured and a base end 13 which is the other end as a lead wire 31. The whole is formed by making it the connection side of.

That is, at the tip portion 12 as one end portion in the length direction of the flexible shaft-like body 11, the tip end which is one end of each metal thin wire 14 from the insulating layer 22 is maintained while maintaining the mutual insulation state. Independently exposed contact ends 15 are formed for each measured part.

In this case, each contact end 15 is sharpened by cutting off the tip portion 12 of the flexible shaft-like body 11 from at least two facing directions so as to be tapered toward the tip end direction, and , And they are exposed in a state in which they are spaced apart from each other via the respective insulating layers 22 with a minute interval.

Further, the rear end portion 13 as the other end portion in the length direction of the flexible shaft-like body 11 is in a state of being non-conducting with each other by interposing each insulating layer 22. Then, the rear end face 14a which is the other end face of each metal fine wire 14 is exposed, and the connecting end 16 for the lead wire 31 is formed by these rear end faces 14a.

On the other hand, FIG. 2 shows another example of the present invention, in which (a) is an enlarged front view with a part omitted.
(B) shows the bottom view (tip side) about (a), respectively. According to these figures, as in the case of FIG. 1, the flexible shaft-like body 11 is obtained by closely twisting two conductive metal wires 14, 14 each surface of which is covered with an insulating layer 22. Are formed. Since the flexible shaft 11 shown in FIG. 2 has the same basic structure as the example shown in FIG. 1, the same parts as those in FIG. To do.

Also in the example shown in FIG. 2, the flexible shaft-shaped body 1
In the tip portion 12 which is one end portion in the length direction of 1, the tip portion which is one end of each thin metal wire 14 is exposed from the insulating layer 22 while maintaining the mutual insulation state, and is independent for the measurement site. The contact end 15 is formed.

In this case, the tip 12 of the flexible shaft 11 is
As shown in the example of FIG. 1, the side is not particularly cut so as to taper toward the tip direction, and only the insulating layer 22 is removed as it is, whereby each thin metal wire 1 is removed.
The front end side of 4 is exposed separately, and each is used as the contact end 15 for the measurement site.

The rear end portion 13 as the other end portion in the length direction of the flexible shaft 11 eliminates the twisted state of the thin metal wires 14, 14 covered with the insulating layer 22. After separating, the rear end faces 14a, which are the other end faces, are exposed separately for each metal thin wire 14, and the connecting end 16 for the lead wire 31 is formed by these rear end faces 14a.

Further, in any of the above examples, the flexible shaft 11 is an insulating tubular material having a high flexibility at least at a portion except the contact end 15 as shown by a broken line in FIG. It is also possible to store and hold in 25.

Since the present invention is constructed in this way, when it is used, for example, the positional relationship is such that its length direction is orthogonal to the plane direction of the base portion provided in a substrate inspection machine (not shown) or the like. The flexible shaft-like body 11 is hung down under the pressure and fixed via the base end portion 12 side.

The flexible shaft 11 is moved up and down relatively with respect to the base and a measuring member (not shown), so that the tip 13 side of the flexible shaft 11 comes into contact with the measured portion of the measuring member.

At this time, the flexible shaft 11 forms an independent contact end 15 for the measured portion by exposing the tips of the two thin metal wires 12 from the insulating layer 22. Therefore, each of these contact ends 15 can be brought into contact with the measurement site at the same time by narrowing the mutual spacing.

Moreover, since the flexible shaft-shaped body 11 is mainly composed of two metal thin wires 12 twisted together, each contact end 15 of these metal thin wires 12 is pressed against the measurement site. When it is bent, it can buckle and bend, and it can be pressed against the measurement site with a strong spring property. Therefore,
Each contact end 15 can be reliably brought into contact with the measurement site.

Further, the fine metal wires 12 constituting the flexible shaft-like body 11 are not a single wire but are twisted into two in a spiral shape so that they are densely integrated with each other. Can be raised.

Further, in the flexible shaft-like body 11 of the present invention, the voltage measuring probe 1 and the current measuring probe 2 are arranged in parallel with each other so as to be separated from each other as in the conventional example of FIG. Different from each other, the spacing between the contact ends 15 and 15 can be narrowed by twisting the thin metal wires 12 together.

Therefore, even if the diameters of the individual thin metal wires 12 are relatively increased, the overall strength can be improved while ensuring a narrow spacing between the contact ends 15, 15.

In particular, as in the case of the flexible shaft 11 shown in FIG. 1, when each contact end 15 whose tip 12 is sharpened so as to be tapered toward the tip is exposed. Can separate the contact ends 15 and 15 from each other with a more preferable minute gap.

Further, since the flexible shaft 11 has a twisted structure, the thin metal wires 14, 14 covered with the insulating layer 22 can be separated from each other very easily as shown in FIG. Therefore, the lead wire 31 for the connection end 16
The connection work such as soldering can be performed more smoothly.

Furthermore, as shown in FIG. 2, the flexible shaft-shaped member 11 except for at least the contact end 15 is covered with an insulating tubular member 25.
When the insulating layer 22 is housed and held inside, the insulating layer 22 can be protected more reliably, which can effectively contribute to the improvement of the measurement accuracy.

Therefore, according to the present invention, it can be suitably used as a multi-terminal for impedance measurement, for example, a four-terminal measurement probe, which realizes a fine pitch by using two flexible shaft-like bodies 11. You can

The present invention has been described above with reference to the illustrated example, and the specific contents of the embodiment are not limited to this. For example, three or more thin metal wires 12 covered with the insulating layer 22 may be used as desired, and these may be twisted together to form the flexible shaft 11. Moreover, although the wire diameter of the metal thin wire 12 is not particularly limited, for example, a wire diameter of about 70 to 100 μm can be preferably used. Furthermore, the flexible shaft 1
The length of 1 may be either long or short as desired.

[0037]

As described above, according to the present invention, the flexible shaft-like body is provided with the contact ends in which the tips of the plurality of thin metal wires are exposed from the insulating layer and are independent of each other. Therefore, the contact ends can be brought into contact with the measurement site at the same time by narrowing the mutual spacing.

Moreover, the flexible shaft-like body is made of a plurality of thin metal wires twisted together to give a buckling force, and has a strong spring property without interposing a coil spring material. Since it is possible to press-contact the measurement site with each other, it is possible to reliably bring each contact end into contact with the measurement site while simplifying the structure.

Further, since the thin metal wires constituting the flexible shaft-like body are not single wires but a plurality of wires are twisted into a spiral shape and are closely integrated with each other,
The strength can be increased without using a sleeve for integration. Therefore, even if the diameter of each thin metal wire is relatively increased, it is possible to improve the overall strength while ensuring a narrow gap between the contact ends.

In particular, in the case where the contact ends of the flexible shaft-like body which are sharpened so as to be tapered toward the front end are exposed to expose the contact ends, the contact ends are formed at a more preferable minute interval. They can be separated from each other. Further, since the flexible shaft-like body adopts the twisted structure, it is possible to separate the metal fine wires covered with the insulating layer from each other very easily, so that the work of connecting the lead wire to the connection end is further facilitated. It can be carried out smoothly.

Furthermore, when the flexible shaft-like body at least at the portion excluding the contact end is housed and held in the insulating tubular member, the protection of the insulating layer can be made more reliable. It can effectively contribute to the improvement of measurement accuracy.

Therefore, according to the present invention, by using a plurality of flexible shaft-like bodies, it can be suitably used as a multi-terminal for impedance measurement which realizes a fine pitch.

[Brief description of drawings]

FIG. 1 shows an example of the present invention, in which (a) is an enlarged front view with a part omitted, and (b) is (a).
3A is a cross-sectional view taken along the line AA in FIG.

FIG. 2 shows another example of the present invention, in which (a) is an enlarged front view with a part omitted, and (b) is a bottom view thereof.

FIG. 3 is an explanatory view showing an example of a conventional structure of a so-called parallel type four-terminal measurement probe.

FIG. 4 is an explanatory view showing an example of a conventional structure of a so-called coaxial type four-terminal measurement probe.

[Explanation of symbols]

11 Flexible shaft 12 Tip 13 Rear end 14 thin metal wires 14a rear end face 15 Contact end 16 connection end 22 Insulation layer 25 Insulating tube material 31 lead wire

Claims (4)

[Claims] 1. A flexible shaft-shaped body is formed by twisting together two or more conductive metal thin wires each surface of which is covered with an insulating layer, and at least the length of the flexible shaft-shaped body is increased. At one end in the vertical direction, one end of each thin metal wire is exposed from the insulating layer while maintaining a mutually insulated state to form an independent contact end for the measurement site, and at the other end, A multi-terminal structure for impedance measurement, characterized in that the other end of each metal thin wire is exposed from the insulating layer while maintaining a mutual insulation state to form a connection end for a lead wire. 2. The multi-terminal structure for impedance measurement according to claim 1, wherein each of the contact ends is sharpened. 3. The multi-terminal structure for impedance measurement according to claim 1, wherein the insulating layer is formed of any one of an insulating resin tube, an insulating coating film, and an insulating coating film. 4. The impedance according to claim 1, wherein at least the portion of the flexible shaft-shaped body excluding the contact end is housed and held in a highly flexible insulating tubular material. Multi-terminal structure for measurement.