JPH02114470A - Electroconductive contact piece - Google Patents

Abstract

PURPOSE:To provide transmission with no ill influence upon the characteristics for sensing signals by forming a needle used as the tip of a probe from one end of a conductive wire. CONSTITUTION:A needle of a conductive probe is formed from one end 40 of a conductive wire 4. At one end 4a of this conductive wire 4, a compression coil spring 5 is wound between a detent 11 and a slipping-off preventive member 15, and the tip 17 of the conductive wire 4 is resiliently protruded from the lower open end 3a of a holder 3, and the end 4a is held while a specified initial load is applied. If the tip 4a of the conductive wire 4 is pressed to a printed circuit board 10, its electric contact with needle 4 is maintained with sufficient load of pressing force. This stabilizes electric resistance on the transmission path incl. the needle 4, and sensing signals can be transmitted stably without having ill influence upon the characteristics for sensing signals.

Description

Detailed Description of the Invention [Object of the Invention] <Industrial Application Field> The present invention relates to a conductive contact suitable for use as a tip of an electrical probe, and in particular, to a conductive contact suitable for use as a tip of an electrical probe, and particularly to a conductive contact suitable for use as a tip of an electrical probe.
The present invention relates to a conductive contact suitable for simultaneously inspecting many points in automatic inspection equipment such as communication equipment, by attaching a large number of probes to a robot arm, etc.

<Prior Art> Probes are generally known for electrically testing printed circuit boards, electronic devices, etc., but they are particularly useful as probe tips for testing high-frequency signals of semiconductors, computers, communication devices, etc. A conductive contact suitable for use must be one that does not have an adverse effect due to internal resistance.

For example, a conductive contact 21 of known type as shown in FIG.
In this case, a conductive needle-like body 24 is received in a cylindrical holder 23 fixed to the support plate 22 so as to be able to reciprocate in the axial direction.

The needle-like body 24 has a constricted shape with large diameter portions at both ends, and the constricted portion has a caulked portion inwardly caulked in an annular manner in the circumferential direction at the intermediate portion of the holder 23. By engaging, removal is prevented.

A compression coil spring 25 is coaxially provided between the bottom wall of the upper part of the holder 23 in the drawing and the base end of the needle-like body 24, and the tip of the needle-like body 24 is connected to the object to be measured (not shown). By further pressing down the support plate 32 by a predetermined amount after contacting the inspection object made of, for example, a printed circuit board, the needle-shaped body 24 can be brought into reliable contact with the spring force. Further, on the bottom wall of the holder 23, a conductive wire 2 is provided as a signal cable for transmitting the detection signal taken out from the part to be measured by the contactor 21 to a measurement circuit (not shown).
6 is connected.

According to the above structure, since the conductive wire 26 and the needle-shaped body 34 are electrically connected to each other via the compression coil spring 23, a detection signal is transmitted via the respective contact portions. . Therefore, in order to obtain the above-mentioned stable internal resistance, the contact portion must be subjected to surface treatment to lower the contact resistance, resulting in an increase in manufacturing costs.

<Problems to be Solved by the Invention> In view of the problems of the prior art, the main object of the present invention is to provide an improved method for transmitting a detection signal without adversely affecting the characteristics of the detection signal using a simple structure. An object of the present invention is to provide a conductive contact.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, the present invention provides a conductive needle body;
A conductive contactor having a conductive wire for transmitting a signal retrieved by bringing the needle-like body into contact with a part to be measured to an external circuit, wherein the needle-like body is connected to one end of the conductive wire. This is achieved by providing a conductive contact characterized by comprising:

<Operation> In this way, since there is no contact part in the transmission path between the conductive needle and the conductive wire, the electrical resistance in the transmission path including the needle is stabilized, making detection possible. The detection signal can be stably transmitted without adversely affecting each characteristic of the signal.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a conductive contact 1 according to the invention. A cylindrical body 14, whose lower end is fixed in a recessed state, is provided on an insulating substrate 2, which forms a part of an automatic inspection device (not shown), so as to stand upright on the upper surface side of the substrate 2 in the figure. A cylindrical holder 3 inserted from below the substrate 2 is coaxially fixed in the cylindrical body 14 so that its lower end protrudes downward from the substrate 2. In addition,
The cylindrical body 14 and the holder 3 are preferably made of, for example, gold-plated nickel silver.

Inside the holder 3, one end portion 4a of a conductive wire 4 is provided which electrically connects the conductive contact 1 and the external measurement circuit 16 to each other.
is received in an axially penetrating state, and its tip 17
is sharpened so as to be able to accurately contact the inspection object, which is a printed circuit board 10 as a part to be measured, and protrudes downward in the figure from one open end 3a of the holder 3. The conductive wire 4 is preferably made of, for example, tungsten material, which has low specific resistance and high hardness.

In the vicinity of the tip 17 of the conductive wire 4, there is a coiled retaining member 15 in which, for example, a nickel-plated wire is tightly wound.
However, it is fixed by brazing (including soft brazing and hard brazing), adhesive, welding, etc. Furthermore, on the inner circumferential surface of the holder 3 near the upper end in the drawing, a circumferentially annular projecting locking portion 11 is provided by caulking the outer circumferential surface radially inward, for example. There is.

A compression coil spring 5 made of, for example, nickel-plated wire is wound around one end 4a of the conductive wire 4 between the locking portion 11 and the retaining member 15. This coil spring 5
One end 6 engages with the retaining member 15, the other end 7 engages with the locking part 11, and the tip 17 of the conductive wire 4 is fixed to the lower open end 3a of the holder 3 in the figure. It is made to protrude elastically from the top. Further, a tight coiled spring 12 wound around the outer peripheral surface of the conductive wire 4 corresponding to the upper part of the holder 3 is fixed by brazing, caulking, etc. in the same manner as the above-described retaining member 15. As shown in FIG. 1, a tightly coiled spring 12 is brought into contact with the locking portion 11 against the biasing force of the compression coil spring 5. Therefore, one end 4a of the conductive wire 4 is held under a predetermined initial load.

According to this embodiment, since the one end 4a of the conductive wire 4 is held with a predetermined initial load applied thereto as described above, the initial position of the tip 17 is stabilized. can be brought into precise contact with the part. When the tip 4a of the conductive wire 4 is pressed against the printed circuit board 10, the compression coil spring 5 is compressed as shown in FIG.
Electrical contact between the sword body 4 and the printed circuit board 10 is ensured by sufficient pressing force.

In this way, since there is no contact part in the signal transmission path from the conductive needle-shaped body for contacting the part to be measured to the measurement circuit 16, only the internal resistance of the conductive wire 4 makes it possible to As a result, the electrical resistance is more stable than in the case where there is a contact conduction part in the transmission path.

Further, according to the present embodiment, since the compression coil spring 5 is wound around the one end 4a of the conductive wire 4 over almost the entire length, the overall length of the compression coil spring 5 is relatively long, and its deformation Since the stroke length is long, sufficient spring force can be ensured even if a coil spring with a relatively small wire diameter and outer diameter is used.

Furthermore, since one end 4a of the conductive wire 4 is received by the holder 3 via the compression coil spring 5 over almost the entire length corresponding to the conductive needle-like body of the contact, the conductive wire 4 has a relatively small diameter. Even if the wire 4 is used, its rigidity is not impaired. Therefore, it is possible to reduce the diameter of the contactor 1 so that it can penetrate into a relatively narrow portion. Further, since the one end portion 4a of the conductive wire 4 is not processed into a constricted shape unlike the conventional type of conductive needle-like body to prevent it from coming off, the number of manufacturing steps can be reduced.

FIG. 3 shows a second embodiment of the present invention, and parts corresponding to the previous embodiment are designated by the same reference numerals and detailed explanation thereof will be omitted. In this second embodiment, a holder 3 is fixed to the substrate 2 in a penetrating state. conductive wire 4
In the vicinity of the tip 17 of the retaining member 1 of the embodiment described above,
Instead of 5, one end 6 of the compression coil spring 5 is wound and fixed by brazing, adhesive, welding, etc. as in the previous embodiment. In some cases, the compression coil spring 5 may be fixed by simply wrapping one end 6 of the spring. Furthermore, a pipe 13 is provided at one end 4a of the conductive wire 4 instead of the close coiled spring 12 of the previous embodiment.
is fixed, and as shown in the figure, one end 4a of the conductive wire 4 is held in a state where the pipe 13 is in contact with the locking part 11 and an initial load force is applied as in the previous embodiment. be done. According to this second embodiment, the number of parts can be reduced because the retaining member 15 is not provided.

[Effects of the Invention] As described above, according to the present invention, with a simple structure, in the conductive contact of the probe, a contact conduction part can be provided in the signal transmission path from the part that contacts the part to be measured to the external circuit. This stabilizes the electrical resistance of the signal transmission path.
The signal can be transmitted by stabilizing each characteristic of the detection signal, and the effect is extremely large.

[Brief explanation of drawings]

1 and 2 are partially cutaway side views showing a first embodiment of a conductive contact according to the present invention. FIG. 3 is a diagram showing a second embodiment of the present invention. FIG. 4 is a partially cutaway side view showing a conventional embodiment.

Claims (1)

[Scope of Claims] A conductive contact having a conductive needle-like body and a conductive wire for transmitting a signal extracted by bringing the needle-like body into contact with a part to be measured to an external circuit. . A conductive contact, wherein the needle-shaped body is formed from one end of the conductive wire.