JPH0260066B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an inspection device that performs electrical tests, inspections, etc. by bringing the tips of contact probes into contact with inspection points on circuit boards such as ICs and LSIs.

[Technical background of the invention and its problems]

A coaxial movable contact probe, in which the inner center conductor of a cylindrical outer conductor is insulated, is supported on a support plate movably provided facing the circuit board to be inspected so as to face the circuit board in a penetrating state. An inspection device for circuit boards, etc., which performs electrical measurement inspection by bringing the tip of a contact probe into contact with a test point on a circuit board by moving a support plate, is described in Japanese Patent Publication No. 175273/1983, for example. It is publicly known.

Due to its coaxial structure, this type of coaxial movable contact probe has advantages such as good impedance matching, low signal leakage, and low signal level attenuation, and can perform electrically good measurements and inspections. can.

However, in conventional coaxial movable contact probes, when the center conductor, which is most prone to failure or damage, fails or is damaged and must be replaced, it is difficult to replace it without also removing other parts such as the outer conductor. Can not. Furthermore, the conventional coaxial type movable contact probe has a relatively complicated mounting structure on the support plate, and has the drawback that it takes time and effort to attach and detach.

Therefore, the present applicant previously proposed in Japanese Patent Application No. 14760/1986 that the center conductor of a coaxial type movable contact probe can be easily inserted and removed, and that the coaxial type movable contact probe can be reliably attached to the support plate. We also proposed a simple inspection device for circuit boards, etc.

As shown in FIG. 1, the coaxial movable contact probe P in this inspection device includes a central conductor 1 and a cylindrical outer conductor 2 provided coaxially around the outer periphery of the central conductor 1. On the inner surface of the outer conductor 2, An insulating cylinder 3 made of an electrically insulating material is fixed, and the central conductor 1 is frictionally inserted into a through hole 4 for inserting the central conductor in the insulating cylinder 3.

An outer tube 5 is integrally fitted on the outer surface of the outer conductor 2, and this outer tube 5 is inserted into an insertion hole 7 provided in a support 6.
It is press-fitted inside.

Recessed portions 8 are formed inside both ends of this outer cylinder 5, and an annular space is formed between the outer conductor 2 and the outer conductor 2. A distal end movable portion 9 and a proximal end movable portion 10 are disposed within each annular space. The inner ends of the cylindrical bodies made of the respective conductors are inserted in a manner that prevents them from coming off. Each of the movable parts 9 and 10 can be freely retracted into the annular space by pressing against the biasing force of a coil spring 11 disposed within the annular space.

On the other hand, the center conductor 1 includes a cylindrical main body 12 and tip pins 1 disposed at both ends of the main body 12 so as to be freely retractable.
3 and a proximal pin 14, each pin 1
3 and 14 are urged outward by a spring built into the main body 12. And this central conductor 1
The axial positioning of the main body 12 is performed by bringing a positioning flange 15 formed at the tip of the main body 12 into contact with the tip surface of the insulating cylinder 3.

Therefore, in the coaxial type movable contact probe P having the above configuration, the tip pin 13 and the tip movable part 9 are pressed against a predetermined point of the circuit pattern with an appropriate back pressure to obtain an electrical connection state, and this probe The signal from the circuit pattern obtained by P is
It is sent to a measuring instrument through a coaxial cable and a connector connected to the probe P via the proximal pin 14 and the proximal movable part 10, and is subjected to measurement and inspection.

By the way, there are movable parts 9 and 10 at both ends of the outer conductor 2.
In this type of coaxial movable contact probe, the probe P becomes thick due to the incorporation of the coil spring 11, etc., and there is a certain limit on the mounting pitch of the probe P to the support plate 6.

In addition, this type of probe has a structure in which each ground is connected via the external conductor 2, so
A large-diameter coaxial cable must be connected to the base end of the probe P, and when there are hundreds of cables, there is a problem that it is not easy to route the wiring.

[Purpose of the invention]

The present invention has been developed in view of the current situation, and it is possible to narrow the mounting pitch of the probe to the support plate to sufficiently correspond to the pattern of the circuit board to be inspected, and to handle the wiring between each probe and the measuring instrument. The purpose of the present invention is to provide an inspection device for circuit boards, etc., which can be easily inspected.

[Summary of the invention]

In the present invention, the movable parts provided at both ends of the external conductor are omitted, and the external conductor is connected to a grounding pin that is disposed through the support plate separately from the probe, and a connecting fitting is provided at a position along the surface of the support plate. It is characterized in that it is connected through the ground pin and grounded through the ground pin.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 2 to 5.

In FIG. 2, 20 is a circuit board to be inspected supported by appropriate means, and this circuit board 20
A support plate 22 serving as a contact probe mounting board is provided below, and is guided by a central support shaft 21 and moves up and down. A large number of coaxial movable contact probes P and ground pins 23 are supported through the support plate 22 in the vertical direction.
Each probe P and ground pin 23 are at the tip (upper end)
When the support plate 22 rises toward the circuit board 20, the tips of each probe P and the ground pin 23 electrically contact the circuit pattern on the lower surface of the circuit board 20, and measurement and inspection are performed. It's becoming like that. Note that the support plate 22 may be fixed and the circuit board 20 may be moved up and down.

A connector holding plate 24 is disposed below the support plate 22 and moves up and down along the support shaft 21 together with the support plate 22.
A connector 26 that electrically connects each probe P to a conductor 25 leading to a measuring device (not shown) and a ground side conductor 27 that electrically connects to the ground pin 23 are provided, and from the ground side conductor 27, The number is significantly smaller than the number of ground pins 23. For example, one or several conductive wires (not shown) are drawn out to ground the ground conductor 27. In FIG. 2, the contact probes P that are paired with each of the three ground pins 23 at both ends are located on the front side or the back side in the direction intersecting the plane of the paper, and are not shown in the figure.

As shown in FIG. 3, the coaxial movable contact probe P includes a central conductor 28 and a cylindrical outer conductor 29 provided coaxially around the outer periphery of the central conductor 28. At the inner end of the outer conductor 29, An insulating tube 30 made of an electrically insulating material is inserted, and is prevented from coming off from the outer conductor 29 by narrowed portions 29a formed at the upper and lower ends of the outer conductor 29. The insulating tube 30 has a center conductor insertion through hole 31 at its axial center, and the center conductor 28 is inserted into this through hole 31.

A flange 32 is integrally formed on the upper outer surface of the outer conductor 29, as shown in FIGS. The insertion position is determined by bringing 32 into contact with the upper surface of support plate 22.

The central conductor 28 has a cylindrical main body 34 and a tip pin 35 and a base pin 36 located at both ends of the main body 34, with bases 35a and 36a of each pin 35 and 36 inside the main body 34. The coil spring 3 is inserted into the main body 34 in a fixed state and is incorporated into the main body 34.
7 through the ball 38. The inner end of the coil spring 37 is received by a bead 39 that has been deformed toward the inside of the main body 34. To position the through hole 31 of the main body 34 in the axial direction, as shown in FIG.
This is done by bringing it into contact with the end face of the

Furthermore, in order to prevent the center conductor 28 from easily coming out of the through hole 31, the center conductor 28 is frictionally inserted into the through hole 31. As a means for generating frictional force, the through hole 31 is made somewhat larger than the center conductor 28, and the main body 34 of the center conductor 28 is slightly curved so that it bends linearly when inserted into the through hole 31. It is possible to do so. The curving of the main body 34 may be performed by applying plastic deformation to the main body material in advance, or by incorporating the tip pin 35 and the base end pin 36 into the main body 34 and then applying curvature to the main body 34. Good too. In addition, instead of providing curvature, a protrusion is formed from the inside to the outside of the main body 34, which has no curvature, and this protrusion is brought into contact with the somewhat elastic insulating cylinder 30, thereby providing a friction retaining function. Good too.

On the other hand, the ground pin 23 consists of a cylindrical main body 42 press-fitted into an insertion hole 41 provided in the support plate 22, a ground pin 43 assembled to both ends of the main body 42, and a base as shown in FIG. Each of the pins 43 and 44 is urged outward by a coil spring (not shown) built into the main body 42 so as to be able to retract and protrude. In addition, the subject 4
2 is positioned in the axial direction by bringing a flange 45 formed on the upper outer surface of the main body 42 into contact with the tip end surface of the support plate 22.

The ground pin 23 and the probe P configured in this way are electrically connected via the connecting fittings 46 at the upper and lower surface positions of the support plate 22, as shown in FIG.

As shown in FIG.
a ring portion 46b that is frictionally attached to the outer circumferential surface of 2;
and a connecting part 46c that connects both ring parts 46a and 46b.This connecting fitting 46 allows the outer conductor 29 of the probe P to function as a ground side. ing.

The circuit board inspection apparatus of the present invention configured as described above performs inspection by relatively moving the contact probe support plate 22 and the connector holding plate 24 toward the circuit pattern of the circuit board 20. The tip pins 35 and 43 of each probe P and each ground pin 23 are pressed against a predetermined point of the circuit pattern by the spring force behind the circuit pattern, and an electrical connection state is obtained. Signals from the circuit pattern are sent to a measuring device (not shown) via each probe P and each ground pin 23, and measurement and inspection are performed there.

At this time, since the space between the center conductor 28 and the outer conductor 29 of the contact probe P is filled with the insulating tube 30, no change in impedance occurs, and there is no disturbance in impedance from the measurement system to the object to be measured. can send signals.

In addition, the ground side is connected from the external conductor 29 to the connection fitting 4.
Since the structure is such that the probe P is connected to the ground pin 23 at 6, the diameter of the probe P becomes small, and the mounting pitch of the probe P to the support plate 22 can be narrowed.

In addition, there is no thick coaxial cable pulled out from each probe P, but only a thin conductor 25, and on the ground side, for example, one ground wire can be taken from the ground side conductor 27, so the wiring can be easily routed. is easy, and the reliability of the operation of the device can be improved.

〔Effect of the invention〕

As explained above, the present invention has a structure in which the center conductor of the probe can be easily attached and detached.
Easy to replace in case of failure or damage. In addition, positioning during insertion is easy, and once inserted, it will not come out unnecessarily.

In addition, since the earth side is constructed so that the external conductor is connected to the ground pin using a grounding metal fitting, the diameter of the probe is reduced, and the pitch at which the probe is mounted on the support plate can be narrowed. As a result, the range of circuit boards that can be inspected is expanded.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the configuration of a coaxial movable contact probe according to the applicant's earlier application, FIG. 2 is a cross-sectional view of the inspection device for circuit boards, etc. of the present invention, and FIG. 3 is a coaxial type movable contact probe used in the present invention. FIG. 4 is an enlarged view of the main part of FIG. 2 showing the relationship between the probe and the ground pin, and FIG. 5 is a plan view of FIG. 4. 20... Circuit board, 22... Support plate, 23...
Grounding pin, 24... Connector holding plate, 28... Center conductor, 29... Outer conductor, 30... Insulating tube, 3
4, 42... Main body, 35, 43... Tip pin, 3
6, 44... Insulating cylinder, 40, 45... Positioning flange, 46... Connection fitting, 46a, 46b...
Ring part, 46c... Connection part, P... Coaxial type movable contact probe.

Claims (1)

[Scope of Claims] 1. A coaxial movable contact probe in which a central conductor is provided in an insulated state inside a cylindrical outer conductor on a supporting plate that is relatively movably provided facing a circuit board to be inspected. It is an inspection device for circuit boards, etc., in which the support plate is supported in a penetrating state toward the circuit board, and the tip of the contact probe is brought into contact with the test point on the circuit board by moving the support plate relative to the circuit board to conduct electrical measurement tests. The center conductor of the contact probe is composed of a cylindrical main body and a tip pin supported at the tip of the main body so as to be freely retractable against a spring force, and a ground pin is provided on the support plate adjacent to the contact probe. An inspection device for a circuit board, etc., characterized in that the circuit board is supported in a penetrating state toward the circuit board, and the ground pin and the external conductor serving as the ground side are connected via a connecting fitting at a position along the surface of the support plate. 2. Claim 1, characterized in that ring portions are provided at both ends of the connecting fitting to be frictionally attached to the ground pin and the outer periphery of the external conductor, respectively.
Inspection equipment for circuit boards, etc., as described in Section 1.