JPH0712846A - Contact probe - Google Patents

Abstract

PURPOSE:To provide a contact probe having self-cleaning function for removing adhered flux or oxides thoroughly. CONSTITUTION:The contact probe comprises hollow plungers 1a, 1c, 1e extending axially, plungers 1b, 1d, 1f inserted into the hollow plungers 1a, 1c, 1e and projecting slightly therefrom, and springs 3a, 3b, 3c, 3d, 3e, 3f for urging the plungers axially upward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact probe, and more particularly to a printed circuit board (hereinafter
This is referred to as a mounting board), and is useful when applied to the case of inspecting the electrical characteristics of a non-cleaning mounting board having a large amount of flux and oxide film.

[0002]

2. Description of the Related Art An in-circuit test and a function test are performed on a mounting board in which an electronic element such as an IC is mounted on a printed board. The in-circuit test is a test for checking whether or not each electronic element has a required characteristic, for example, resistance, inductance, or capacitance, and the function test is a test for checking the input / output characteristics required by the electric circuit formed on the mounting board. It is a test to check whether or not it has.

To perform such an in-circuit test or a function test, a fixture type inspection device is used.

FIG. 3 is a perspective view of a fixture type inspection apparatus, and FIG. 4 is a perspective view showing an inspection state by the fixture type inspection apparatus.

As shown in FIG. 3, the fixture type inspection apparatus has an upper fixture 11 and a lower fixture 12. Of these, the upper fixture 11 is
It is a square plate-shaped member and has positioning holes 13 at its four corners.
And a large number (100
It has 0 to 2000 contact probes 14 and moves up and down by an elevating mechanism (not shown). The lower fixture 12 is a square plate-shaped member, and has positioning pins 15 at the four corners of its upper surface and a large number (about 1000 to 2000) of contact probes 16 and substrate positioning pins 17 at the center. In addition, its lower surface is fixed to the base 18 of the device.

Next, the procedure for inspecting the mounting board by the above-mentioned fixture type inspection apparatus will be described with reference to FIG. As shown in the figure, the mounting substrate 20 includes an electronic element 22 such as an IC on a substrate 21 in which two reference holes 23 are formed.
Is mounted by soldering. Therefore, first, the board positioning pin 17 is inserted into the reference hole 23 to mount the board 20.
Determine the position of. Next, the positioning pin 15 is positioned in the positioning hole 1.
The upper fixture 11 is lowered while aligning so that the upper fixture 11 fits in the position 3. As a result, the tip (lower end) of the contact probe 14 contacts the inspection point on the upper surface of the mounting board 20, and the tip (upper end) of the contact probe 16 contacts the inspection point on the lower surface of the mounting board 20. That is, the contact probes 14 and 16 are arranged so that the tips thereof contact the inspection point. After such a contact state, various inspections are performed by applying a voltage or passing a current to each of the inspection points via the contact probes 14 and 16. After the inspection is completed, the upper fixture 11 rises and the mounting board 20 is removed.

FIG. 5 is a vertical sectional view of a contact probe according to the prior art. As shown in the figure, the contact probe according to the conventional technique includes a plunger 31 and a barrel 2.
And a spring 33. Barrel 2 of these
Is a container having an open upper end, and has a narrowed portion inside thereof. The plunger 31 is a columnar member, and has a shoulder part in the middle of its axial direction. The plunger 31 is housed in the barrel 2 so as to be movable in the axial direction, and its shoulder portion abuts against the narrowed portion of the barrel 2 so that the axial position thereof is regulated, and the tip portion of the plunger 31 is of the barrel 2. It projects from the opening. As shown in the perspective view of FIG. 6, the tip of the plunger 31 has several tips 31a, and an acutely cut valley 31b between the tips 31a. is doing. That is, the tip portion of the plunger 31 has a so-called crown shape formed in a crown shape.

The spring 33 is in the barrel 2 and
The lower end is connected to the bottom of the plunger 31 and the upper end is connected to the inner bottom surface of the barrel 2. That is, the spring 33 exerts an upward force on the plunger 31 along the axial direction (hereinafter, simply referred to as an upward force).
Is giving.

[0009]

In the contact probe according to the prior art as described above, the tip 31a of the plunger 31 contacts the inspection point of the mounting board. At that time, the flux and the oxide film (hereinafter referred to as flux) peel off from the inspection point of the mounting board, but the flux and the like are removed by spilling from the valley portion 31b. That is, the plunger 31 is of a so-called self-cleaning type in which the valley portion 31b has an acute angle so that flux and the like are easily spilled.

However, when there is a large amount of flux or the like as in a non-cleaned mounting substrate, the separated flux and the like is not completely removed and remains attached to the tip of the plunger 31. Therefore, it is necessary to clean the tip portion of the plunger 31 by brushing or the like because there is a risk of contact failure.

In view of the above-mentioned prior art, it is an object of the present invention to provide a contact probe having a self-cleaning function capable of completely removing attached flux and the like.

[0012]

The structure of the present invention for achieving the above object is movably accommodated in an axial direction in a barrel having one axial end opened, and a shoulder portion abuts a narrowed portion of the barrel. This restricts the position in the axial direction so that the tip portion projects from the opening, and has a first plug having a through hole extending in the axial direction at the center thereof, and an axial direction with respect to the first plug. A first elastic member that applies a force in a direction toward the tip thereof, and a member that is inserted through the through hole of the first plunger so as to be movable in the axial direction, and the tip thereof is the tip of the first plunger. It is characterized by having a more protruding second plug and a second elastic member for applying a force to the second plug in a direction toward the tip end along the axial direction.

[0013]

According to the present invention having the above-mentioned structure, the flux and the like separated from the mounting substrate are completely removed by moving in the axial direction when the second plunger comes in contact with and separates from the inspection point.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. It should be noted that the same parts as those of the conventional technique are denoted by the same reference numerals, and duplicate description will be omitted.

FIG. 1A is a vertical sectional view of a contact probe according to the first embodiment of the present invention. As shown in the figure, the contact probe according to the first embodiment includes a plunger 1a, 1b, a barrel 2 and springs 3a, 3b.
Have.

Of these, the plunger 1a is a plunger having a crown-shaped tip like the plunger 31 shown in FIG. The plunger 1a has a through hole extending in the axial direction at the center thereof, both ends open, and a shoulder portion in the middle of the axial direction. Further, the plunger 1a is accommodated in the barrel 2 so as to be movable in the axial direction, and its shoulder portion abuts on the narrowed portion of the barrel 2 so that the axial position is regulated and the tip portion thereof is opened in the barrel 2. Protruding from. The plunger 1b is a T-shaped member,
That is, it is a member having a spire-shaped vertical portion and a flat portion formed at the lower end of the vertical portion and having an outer shape slightly smaller than the inner shape of the barrel 2. Moreover, Plunger 1
The vertical portion of b is axially movably inserted through the central portion of the plunger 1a. Further, normally, the elastic forces of the spring 1a and the spring 1b are balanced, and the tip of the plunger 1b is located at a position slightly protruding from the tip of the plunger 1a.

The spring 3a is in the barrel 2 and
The upper end is connected to the lower surface of the horizontal portion of the plunger 1b, and the lower end is connected to the inner bottom surface of the barrel 2. Moreover, the spring 3a gives an upward force to the plunger 1b. The spring 3b is inside the barrel 2, and has its upper end connected to the lower end of the plunger 1a and its lower end connected to the upper surface of the horizontal portion of the plunger 1b. Moreover, the spring 3b gives an upward force to the plunger 1a.

FIG. 1B is a vertical sectional view of a contact probe according to the second embodiment of the present invention. As shown in the figure, the contact probe according to the second embodiment has a plunger 1c, 1d, a barrel 2 and springs 3c, 3d.
Have.

Of these, the plunger 1c is a plunger having a crown-shaped tip like the plunger 31 shown in FIG. The plunger 1c has a through hole extending in the axial direction at the center thereof and an open upper end. Further, the plunger 1c has a shoulder part in the middle of the axial direction, and has a narrowed part in its through hole. Further, the plunger 1c is housed in the barrel 2 so as to be movable in the axial direction, and its shoulder portion abuts on the narrowed portion of the barrel 2 so that the axial position thereof is regulated, and the tip end portion thereof is opened from the opening of the barrel 2. It is protruding. The plunger 1d is a substantially T-shaped member, that is, a member having a cylindrical lower portion, a shoulder portion continuing to the upper end of the lower portion, and a spire-shaped upper portion continuing to the shoulder portion.

Further, the plunger 1d is inserted into the plunger 1c so as to be movable in the axial direction, and its shoulder portion abuts against the narrowed portion of the plunger 1c so that its axial position is regulated. The tip is occupying a position slightly protruding from the tip of the plunger 1d.

The spring 3c is in the barrel 2 and
The upper end is connected to the outer bottom surface of the plunger 1c,
Its lower end is connected to the inner bottom surface of the barrel 2. Moreover, the spring 3c gives an upward force to the plunger 1c. The spring 3d is the plunger 1
In c, the upper end is connected to the lower end of the plunger 1d, and the lower end is connected to the inner bottom surface of the plunger 1c. Moreover, the spring 3d gives an upward force to the plunger 1d. Spring 3
The elastic force of d is weaker than that of the spring 3c. That is, when a load is applied only to the tip of the plunger 1d,
Only the plunger 1d is lowered and the plunger 1c is not lowered at the same time.

FIG. 1D is a vertical sectional view of a contact probe according to the third embodiment of the present invention. As shown in the figure, the contact probe according to the third embodiment has a plunger 1e, 1f, a barrel 2 and springs 3e, 3f.
Have.

Of these, the plunger 1e and the plunger 1f have the same shape and mutual relationship as the plunger 1c and the plunger 1d shown in FIG. 1 (b). However, the plunger 1e does not have a bottom surface and the lower end is also open, and this point is the only difference.

The spring 3e is in the barrel 2 and
The upper end is connected to the lower end of the plunger 1e, and the lower end is connected to the inner bottom surface of the barrel 2. Moreover, the spring 3e gives an upward force to the plunger 1e. The spring 3f is inside the barrel 2,
Its upper end is connected to the lower end of the plunger 1f, and its lower end is connected to the inner bottom surface of the barrel 2. Moreover, the spring 3f gives an upward force to the plunger 1f.

According to the above embodiment, when the contact probe contacts the test land 4 which is the inspection point of the mounting board 5 as shown in FIG. 2, the inner plunger 1b,
The protrusions 1d and 1f project further than the outer plungers 1a, 1c, and 1e, so that they are largely dented into the barrel 2 and their tip positions are aligned. After that, when the contact probe separates from the test land 4, the original state again, that is, the tips of the plungers 1b, 1d and 1f are moved to the plunger 1.
It is in a state of slightly protruding from the tips of a, 1c, and 1e.

Thus, the plungers 1b, 1d, 1f
Moves in the axial direction relative to the plungers 1a, 1c, 1e, and at that time, the flux and the like adhering to the tips thereof are removed. Note that FIG. 2 shows only the state of the tip portion of FIG. 1 (c) which is the third embodiment, but regarding (a) and (b) of FIG. 1 which is the first and second embodiments. Is also the same.

The plungers 1a to 1f are made of durable materials such as beryllium copper and carbon tool steel.

[0028]

As described in detail in connection with the above embodiments, the present invention can completely remove flux and the like, and there is no possibility of contact failure of the contact probe with respect to the mounting board, which is stable. You can get contact.

The mounting board has been conventionally cleaned with chlorofluorocarbon, but it tends to be non-cleaning as the use of fluorocarbon is restricted for environmental protection. The present invention is very effective for such a non-cleaning mounted substrate containing a large amount of flux and the like, and contributes to the non-cleaning.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a contact probe according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing an extracted tip portion of a contact probe according to an embodiment of the present invention.

FIG. 3 is a perspective view of a fixture type inspection device.

FIG. 4 is a perspective view showing an inspection state by a fixture type inspection device.

FIG. 5 is a vertical cross-sectional view of a contact probe according to the related art.

FIG. 6 is a perspective view of a tip portion of a contact probe according to a conventional technique.

[Explanation of symbols]

 1a, 1b, 1c, 1d, 1e, 1f Plunger 2 barrel 3a, 3b, 3c, 3d, 3e, 3f Spring

Claims (1)

[Claims] 1. A barrel movably in the axial direction is housed in a barrel having one end in the axial direction opened, and a shoulder portion abuts on a narrowed portion of the barrel to regulate the axial position, and the tip portion is opened. A first plunger having a through-hole extending in the axial direction at the center thereof and projecting from the first plunger, and a first elasticity for applying a force to the first plunger in the axial direction toward the tip thereof. A member; and a second plunger that is inserted through the through hole of the first plunger so as to be movable in the axial direction and has a tip protruding from the tip of the first plunger. And a second elastic member that applies a force to the second plunger in a direction toward the tip thereof along the axial direction.