JPH09178772A - Spring probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a stable electrical connection regardless of the movement of a plunger. SOLUTION: When a tip 11a of a plunger is pressed against an electrode 20 of a body to be inspected, the plunger moves toward the inside of a barrel 12. The inner-periphery side of a volute spring 13 is fixed to the plunger and the outer-periphery side is fixed the barrel 12. The move of the plunger is absorbed by the deviation between the inside and outside of the volute spring 13. Then, although the plunger is pressed against the electrode 20 by the force of the volute spring 13, an electrical connection can be stably maintained since there is no relative move of connection part due to the movement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spring probe which is pressed against an object to be inspected or an electrode to be connected for electrical inspection, measurement and connection of semiconductor elements, electronic devices, circuit boards and the like.

[0002]

2. Description of the Related Art Conventionally, various probes have been used to inspect various circuits and the like formed on a printed circuit board.
This probe presses its tip against the electrode on the substrate,
By making electrical contact with an electrode, it is used to detect the electrical state of the electrode (for example, the state of the signal output from the electrode) and to input a predetermined signal thereto.

FIG. 1 shows an example of a conventional probe.
The plunger 1 which functions as a movable pin for making contact with the object to be inspected has a cylindrical shape, and a tip 1a thereof has a conical shape. There are various shapes of the tip. A spindle-shaped base end 1b is provided at the opposite end (base end). The proximal end side of the plunger 1 is housed in a pipe-shaped barrel 2 having a closed end. Therefore, from the one end side of the barrel 2 to the plunger 1
Has a protruding shape.

A coil spring 3 is inserted and arranged between the closed end of the barrel 2 and the base end 1b of the plunger 1. The coil spring 3 is attached so that the plunger 1 faces the tip side thereof. I am energetic. Further, a groove portion 2a that is recessed inward is formed in the middle portion of the barrel 1, and the inner surface of the groove portion 2a forms the base end portion 1 of the plunger 1.
The movement of b to the tip side is stopped.

When using such a probe,
The tip portion of the plunger 1 is pressed against a desired electrode on a printed board which is an object to be inspected. As a result, the plunger 1 retracts according to the pressing force in the barrel 2, but the coil spring 3 presses the plunger 1 toward the tip side. Then, the tip 1a of the plunger 1 is pressed against the electrode. Since the plunger 1, the barrel 2 and the coil spring 3 are all made of a conductive metal material, electrical continuity between the electrode and the inspection device supporting the probe is achieved through the probe, and The inspection is done. In addition, since the plunger 1 moves,
In the probe, basically, an electric current flows through the plunger 1, the coil spring 3, and the barrel 2.

Further, FIG. 2 shows another conventional example, in which the coil spring 3 side of the base plate portion 1b of the plunger 1 is obliquely cut out to form a flat surface at a predetermined angle with respect to the axis.
The ball 4 is arranged between this plane and the coil spring 3. Therefore, the plunger 1 is biased by the coil spring 3 via the ball. Then, the ball 4 is pushed in one direction by the base end portion 1b of the plunger, so that the outer circumference of the ball 4 is pressed against and brought into contact with the inner circumferential surface of the barrel 2.

Therefore, in this probe, a current basically flows through the plunger 1, the ball 4 and the barrel 2.

As described above, according to the above-mentioned conventional example, by pressing the tip of the probe against an arbitrary portion of the object to be inspected, the contact resistance can be reduced by a sufficient contact pressure, and a suitable inspection can be performed.

[0009]

However, in the conventional example shown in FIG. 1, the current flows through the thin coil spring 3. Therefore, there is a problem that an inductance is generated here and the change of the signal cannot be transmitted sufficiently accurately. There is also a problem that the current path changes depending on the contact state of the coil spring 3 and the barrel 2 and the electrical resistance changes, which makes the inspection unstable.

On the other hand, in the conventional example of FIG. 2, the ball 4 solves the above problem, but the sliding portion between the ball 4 and the barrel 2 achieves electrical conduction. Further, this contact resistance cannot always be made uniform, an unstable factor remains, and there is a problem that a sufficiently stable inspection cannot be performed.

The present invention has been made to solve the above problems, and eliminates unstable factors.
An object of the present invention is to provide a spring probe that can perform stable inspection.

[0012]

A spring probe according to the present invention comprises a rod-shaped plunger whose tip portion is pressed against and contacted with an object to be inspected, and a tubular barrel which accommodates the plunger portion with its tip side protruding. And a bamboo shoot spring which is spirally wound as a whole and whose outer diameter side is fixed to the inner peripheral portion of the barrel and whose inner diameter side is fixed to the outer peripheral portion of the plunger and elastically supports the plunger so that the plunger can advance and retract with respect to the barrel. .

Therefore, when the plunger is pressed against the electrode or the like, the force of the bamboo shoot spring urges the plunger toward the electrode. The bamboo shoot spring only shifts inside, and the inner circumference side and the outer circumference side are fixed to the plunger and the barrel, and there is no sliding movement here. Therefore, there is no sliding portion in the electrical path from the tip of the plunger to the barrel, and movement of the plunger does not adversely affect the transmission of electrical signals.
Therefore, stable electrical connection can always be maintained, and stable inspection can be performed.

In another invention, the barrel, the plunger and the bamboo shoot spring are all made of a conductive material. Thus, a suitable transmission of electrical signals is achieved via them.

In still another aspect of the invention, an outer diameter side of the bamboo shoot spring is formed with an inwardly projecting portion provided on the barrel, and the plunger fixes the plunger to the barrel. As a result, the movement of the plunger can be received by the protruding portion, and reliable fixing can be achieved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings. FIG. 3 is a diagram showing a configuration of a main part of the embodiment, and the plunger 11 has a columnar (bar) shape. Plunger 11
11a has a conical shape, and the base end side is cut into a plane perpendicular to the axis. The base end side may extend downward in the figure. The proximal end side of the plunger 11 is housed in a barrel 12 having a diameter larger than that of the plunger 11. The barrel 12 has a tapered front end 12a and an inner diameter that is substantially the same as the outer diameter of the plunger 11 to prevent lateral deflection of the plunger 11.

In the barrel 12, a bamboo shoot spring 13 is arranged so as to surround the periphery of the base end side of the plunger 11. An end portion on the inner diameter side of the bamboo shoot spring 13 is joined and fixed to the outer circumference of the plunger 11, and an outer circumferential side is fixed to the inner wall of the barrel 12. Here, as shown in FIG. 4, the bamboo shoot spring 13 has an end portion on the outer peripheral side and an end coil portion (indicated by dots in the figure) that does not deform at the end portion on the inner peripheral side. Then, the end turn portions are connected to the plunger 11 and the barrel 12, respectively.

In this example, the inner diameter side of the bamboo shoot spring 13 is fixed to the plunger 11 with a conductive adhesive. Further, a protrusion may be formed at a position where the plunger 11 is in contact with the bamboo shoot spring 13 to increase the axial fixing strength between the bamboo shoot spring 13 and the plunger 11. This protrusion is
It is preferably formed by joining the flange to the plunger 11. Note that the adhesion may be stopped.

On the other hand, the outer diameter side of the bamboo shoot spring 13 may be fixed to the inner wall of the barrel 11 with a conductive adhesive. In this example, the barrel 11 is provided with a circumferential groove 12b in a predetermined portion of the barrel 11, thereby fixing the bamboo shoot spring 13 against the downward movement in the drawing. Further, the tip portion 12a of the barrel 12 also prevents the bamboo shoot spring 13 from moving upward in the drawing. In this way, the bamboo shoots 13 become the barrel 12.
Attached to. Note that the adhesion on the outer peripheral side may be stopped.

In manufacturing this probe, first, the plunger 11 and the bamboo shoot spring 13 are joined, and then the bamboo shoot spring 13 having the plunger 11 attached thereto is housed in the cylindrical barrel 12. At this time, the bamboo shoot spring 13 is pushed in until it comes into contact with the groove 12b. Then, the outer circumference of the bamboo shoot spring 13 and the inner wall of the barrel 12 are bonded. Then, the tip side of the barrel 12 is caulked to form a tapered tip portion 12a, and the bamboo shoot spring 13 is fixed, and at the same time,
Fix the plunger 11.

Further, the barrel 12 can be divided into upper and lower parts, and in the divided state, the bamboo shoot spring 13 is attached to the barrel 1.
Alternatively, the barrel 12 may be housed on one side, and then the barrel 12 may be joined (for example, screwed). In this way, the tip of the barrel 12 can be tapered in advance.

Furthermore, it is conceivable to form a groove in the axial direction in the inner peripheral portion of the bamboo shoot spring 13 and to provide the plunger 11 with a projection having a size corresponding to this groove. With this configuration, the protrusion is positioned in the groove, and the plunger 11 is moved in this state to pass through the bamboo shoot spring 13. Then, by rotating the plunger 11, the axial fixing of the plunger 11 and the bamboo shoot spring 13 can be achieved.

When using such a probe,
The tip 11a of the plunger 11 is pressed against the electrode 20 of the object to be measured. This state is shown in FIG. As a result, the plunger 11 moves inside the barrel 12 to the lower side in the figure. Then, the inside of the bamboo shoot spring 13 moves downward in the figure, and the plunger 1 is moved by the bamboo shoot spring 13.
1 is biased upwards. Therefore, the tip 11a of the plunger 11 is pressed against the electrode 20 with a desired pressure.

Here, the plunger 11 and the bamboo shoot 1
3 and the barrel 12 are both formed of a conductor, and the inspection device supporting the barrel 12 is electrically conductively connected to the electrode 20. Therefore, the inspection device can inspect the electrical state of the electrode 20. Also, a predetermined signal can be supplied from the inspection device to the electrode 20.

Here, the electrical connection between the barrel 12 and the plunger 11 is made by the bamboo shoot spring 13,
The joint portion of the bamboo shoot spring 13, the barrel 12 and the plunger 11 is fixed and does not slide. Therefore, even if the plunger 11 moves, the electrical conduction path in the probe does not change at all. Therefore, the plunger 1
A stable inspection can be performed by pressing the desired one.

FIG. 6 shows a shape of the bamboo shoot spring 13 which is protruded toward the inner side in a normal state. Even if such a bamboo shoot spring 13 is used, as in the above case,
A suitable electrical contact with the electrode can be made, and a stable electrical connection can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a conventional example.

FIG. 2 is a diagram showing a configuration of another conventional example.

FIG. 3 is a diagram showing a configuration of a spring probe according to the present invention.

FIG. 4 is a diagram showing a configuration of the bamboo shoot spring as viewed in the axial direction.

FIG. 5 is a diagram showing a state in which a probe is pressed against an electrode.

FIG. 6 is a view showing a bamboo shoot spring having another configuration.

[Explanation of symbols]

11 Plungers, 12 barrels, 13 bamboo shoots.

Claims (3)

[Claims] 1. A rod-shaped plunger whose tip portion is pressed against and brought into contact with an object to be inspected, a tubular barrel which accommodates the plunger portion with its tip end protruding, and a rod-shaped plunger that is spirally wound as a whole, and has an outer diameter side. A spring probe, which is fixed to the inner peripheral portion of the barrel and the inner diameter side of which is fixed to the outer peripheral portion of the plunger, and which elastically supports the plunger so as to advance and retract with respect to the barrel. 2. The spring probe according to claim 1, wherein the barrel, the plunger, and the bamboo shoot spring are all made of a conductive material. 3. The spring probe according to claim 1, wherein an outer diameter side of the bamboo shoot spring is formed with an inwardly projecting portion provided on the barrel, and the plunger fixes the barrel to the barrel. The spring probe is characterized by