JP2024106228A - MEASUREMENT PROBE AND PROBE UNIT COMPRISING THE MEASUREMENT PROBE - Google Patents

Abstract

[Problem] To stabilize the value of contact resistance with a simple structure while maintaining the functions of conventional probes, thereby enabling more accurate evaluation of an object to be measured. [Solution] A pair of plungers 2, each having an outer step and an inner step, arranged so that first ends that contact electrodes face opposite each other, an elastic member 3 arranged between the pair of plungers 2 so as to bias the pair of plungers 2 in a direction separating them from each other, a barrel 4, one end of which contacts the outer step formed on one of the pair of plungers 2 and the other end of which contacts the outer step formed on the other of the pair of plungers 2 so as to allow the pair of plungers 2 to move in the longitudinal direction, and housing the second end of the pair of plungers 2 opposite the first ends and the elastic member therein, and a contact member 5 arranged so as to contact the inner step of the pair of plungers 2 and the inner wall surface of the barrel 4. [Selected Figure] Figure 3

Description

An embodiment of the present invention relates to a measurement probe and a probe unit including the measurement probe.

Probe units have traditionally been used to electrically connect an object to be measured, such as an IC chip, to a tester that measures the object. In recent years, the pitch of the electrodes on the object to be measured has become smaller than the pitch of the connector on the tester side. Therefore, probe units such as those described above are used to convert this pitch difference.

The probe unit comprises a probe holder on which the object to be measured is placed, a connector that is connected to the connector of the tester, and an electrode plate that electrically connects the probe holder to the connector. The probe holder has probes arranged in a manner that corresponds to the pitch of the electrodes of the object to be measured. The upper ends of the probes protrude from the probe holder and come into contact with the electrodes of the object to be measured. The connector is formed to correspond to the pitch of the connector on the tester side.

Here, the structure of a conventionally used probe will be explained with reference to FIG. 8. FIG. 8 is a cutaway end view showing the entire probe 100 used in a conventional probe unit so that its interior can be seen.

The probe 100 comprises a pair of tubular conductors 101, 101 arranged with their tips facing outward, a coil spring 102, and a barrel 103. The coil spring 102 is arranged between the pair of tubular conductors 101, 101 so as to bias the pair of opposing tubular conductors 101, 101 on the opposite side of the tips in a direction separating them from each other. The barrel 103 is formed in a cylindrical shape that houses a part of the tubular conductors 101, 101 and the coil spring 102 inside.

The pair of tubular conductors 101, 101 each have a step portion 101a, 101a that contacts the openings at both ends of the barrel 103. Therefore, they will not pop out from the barrel 103 due to the biasing force of the coil spring 102, and when the object to be measured is not placed on the probe holder, the pair of tubular conductors 101, 101 in the probe 100 will be in a state of protruding outward.

Furthermore, as described above, the pair of tubular conductors 101, 101 are in contact with the coil spring 102 on opposite ends of their tips, and are therefore movable in the longitudinal direction of the probe 100, as shown by the double-headed arrows in Figure 8.

In other words, since the probe 100 employs such a structure, the pair of tubular conductors 101, 101 can each move longitudinally toward the inside of the barrel 103. Therefore, when an object to be measured is placed on the probe unit, the tip of the tubular conductor 101 comes into contact with the electrode and is pushed into the inside of the barrel 103.

As mentioned above, the probe unit serves to electrically connect the object to be measured and the tester. In other words, the tip of the probe 100 (tubular conductor 101) contacts the electrode of the object to be measured, thereby mediating between the object to be measured and the tester. As a result, a current flows through the probe 100, and the mechanism behind this is as follows.

First, both ends of the coil spring 102 are in contact with a pair of tubular conductors 101, 101 that face each other on opposite sides of the tips of the tubular conductors 101 inside the barrel 103. Therefore, the length of the coil spring 102 is approximately the same as the distance between the pair of tubular conductors 101, 101 that face each other on opposite sides of the tips inside the barrel 103.

In this state, when the tip of the probe 100, i.e., one of the tubular conductors 101, comes into contact with an electrode of the object to be measured, the tubular conductor 101 is pushed into the barrel 103. This movement of the tubular conductor 101 causes the coil spring 102 in contact with the tubular conductor 101 inside the barrel 103 to contract.

Since the coil spring 102 is made of a conductive material, when a current flows through the probe 100, the current flows in the following order: the electrode of the object to be measured, one of the tubular conductors 101 in contact with that electrode, the coil spring 102, and the other tubular conductor 101.

When one of the tubular conductors 101 comes into contact with the electrode of the object to be measured and is pushed into the barrel 103, the coil spring 102 contracts, flexing and bending, with part of it coming into contact with the inner wall of the barrel 103. The contact of the coil spring 102 with the inner wall of the barrel 103 also establishes electrical continuity between the object to be measured and the tester.

JP 2021-189052 A

However, when the coil spring 102 comes into contact with the inner wall of the barrel 103, contact resistance is generated. If this contact resistance fluctuates significantly when determining the performance of the object being measured, it may become difficult to accurately evaluate the performance of the object being measured.

In addition, due to the structure of the probe described above, the position at which the coil spring 102 contacts the barrel 103 may change. That is, as described above, the pair of tubular conductors 101, 101 are biased in a direction separating them from each other by the coil spring 102 being disposed between them inside the barrel 103.

Thus, although such a biasing force is applied to the pair of tubular conductors 101, 101, between them and the barrel 103, the step portions 101a, 101a only come into contact with the openings at both ends of the barrel 103.

Therefore, the relative positional relationship between the tubular conductor 101 and the barrel 103 may be shifted. In other words, the pair of tubular conductors 101, 101 may rotate due to movement in the longitudinal direction of the probe 100. This rotation may also cause the coil spring 102 to rotate inside the barrel 103.

When the position of the coil spring 102 inside the barrel 103 changes, the coil spring 102 bends and the position at which it contacts the inner wall of the barrel 103 changes. Such changes in the contact position also have a significant effect on the value of the contact resistance, and unstable fluctuations in the contact resistance hinder accurate evaluation of the object being measured.

In addition, since the coil spring 102 is housed inside the barrel 103, it is not possible to control the contact position of the coil spring 102 with the inner wall of the barrel 103.

The present invention aims to provide a measurement probe and a probe unit equipped with the measurement probe that can perform more accurate evaluation of the object to be measured by stabilizing the contact resistance value with a simple structure while maintaining the functionality of conventional probes.

The measurement probe according to one aspect of the present invention includes a pair of plungers arranged such that their first ends in contact with the electrodes face in opposite directions, and having an outer step on the outer peripheral surface that projects outward in the short direction perpendicular to the longitudinal direction from the outer peripheral surface, and an inner step on the outer peripheral surface that faces inward in the short direction from the outer peripheral surface; an elastic member arranged between the pair of plungers so as to bias them in a direction separating them from each other; a barrel having one end in contact with the outer step formed on one of the pair of plungers and the other end in contact with the outer step formed on the other of the pair of plungers so as to allow the pair of plungers to move in the longitudinal direction, and housing the second end of the pair of plungers opposite the first end and the elastic member inside; and a contact member arranged to contact the inner step of the pair of plungers and the inner wall surface of the barrel.

In addition, a probe unit according to one aspect of the present invention includes a pair of plungers arranged so that the first ends in contact with the electrodes face in opposite directions, the pair of plungers having an outer step on the outer peripheral surface that protrudes outward in the short direction perpendicular to the longitudinal direction from the outer peripheral surface, and an inner step on the outer peripheral surface that faces inward in the short direction from the outer peripheral surface, an elastic member arranged between the pair of plungers so as to bias them in a direction separating them from each other, a barrel having one end in contact with the outer step formed on one of the pair of plungers and the other end in contact with the outer step formed on the other of the pair of plungers so as to allow the pair of plungers to move in the longitudinal direction, and housing the second end of the pair of plungers opposite the first end and the elastic member inside, and a contact member arranged to contact the inner step of the pair of plungers and the inner wall surface of the barrel, a probe holder that holds the measurement probe and places an object to be measured on, a connector terminal that is connected to a tester, and an interface probe holder that connects the probe holder and the connector terminal.

The present invention provides a measurement probe and a probe unit equipped with the measurement probe that can stabilize the contact resistance value with a simple structure while maintaining the functionality of conventional probes, thereby enabling more accurate evaluation of the object to be measured.

1 is an external view showing a configuration of a probe unit according to an embodiment of the present invention; 1 is an external view showing an entire measurement probe according to an embodiment of the present invention; 3 is a cross-sectional end view showing the measurement probe shown in FIG. 2 cut in the longitudinal direction. FIG. FIG. 4 is an enlarged explanatory diagram showing a portion surrounded by a dashed line in the configuration diagram of the measurement probe in FIG. 3 . 3 is an enlarged cross-sectional view showing a state cut along line AA in the configuration diagram of FIG. 2. FIG. FIG. 4 is a partially enlarged view showing another embodiment of the measurement probe according to the present invention. FIG. 11 is a partially enlarged view showing still another embodiment of the measurement probe according to the present invention. FIG. 1 is a cutaway end view showing an entire probe used in a conventional probe unit such that the inside of the probe is visible.

The measurement probe according to the embodiment of the present invention will be described below with reference to the drawings as appropriate. First, the configuration of the probe unit 10 in which the measurement probe is used will be described. Figure 1 is an external view showing the configuration of the probe unit 10 according to the embodiment of the present invention.

The probe unit 10 according to the embodiment of the present invention is used to inspect the performance of an object to be measured, such as an IC chip. As shown in FIG. 1, the probe unit 10 includes a work-side probe holder 20 having a plurality of measurement probes 1, an interposer 30, an interface probe holder 40, and a terminal block 50 having a plurality of connector terminals 5a. In addition, the probe unit 10 includes screws, positioning pins, etc. (not shown).

The probe unit 10 is stacked from the top in the following order: work-side probe holder 20, interposer 30, interface probe holder 40, and terminal block 50, and secured with screws. Positioning pins are provided to penetrate these components and are used to align the components.

The workpiece side probe holder 20 holds the object to be measured and the measurement probe 1 that contacts the electrodes of the object to be measured. Because it is necessary to position the measurement probe 1 in accordance with the position of the electrodes of the object to be measured, it is designed according to the object to be measured.

The interposer 30 is used to convert the pitch of the measurement probe 1 held by the work-side probe holder 20 into the pitch of the electrodes on the tester side. The interface probe holder 40 is used to electrically connect the interposer 30 and the terminal block 50.

Furthermore, the terminal block 50 is the part that is connected to the tester. The terminal block 50 includes an insulating plate (not shown) and a plurality of conductive connector terminals 5a provided on the plate.

The connector terminal 5a provided on the terminal block 50 is connected to a printed circuit board 60 or a connector cable of a tester (not shown), for example, as shown in FIG. 1. When the connector terminal 5a is connected to the printed circuit board 60, the connector terminal 5a is inserted into a through hole 61 provided in the printed circuit board 60 and soldered. When the connector terminal 5a is connected to a connector cable 70, the connector terminal 5a is inserted into a connector 71 of the connector cable 70.

When the probe unit 10 is used to inspect the performance of an object to be measured, the object to be measured is placed on the work-side probe holder 20. At this time, the electrode of the object to be measured contacts the tip of a plunger (described later) of the measurement probe 1. Then, the connector terminal 5a of the terminal block 50, which is electrically connected to the measurement probe 1, is connected to a tester (not shown) that inspects the object to be measured.

Next, the measurement probe 1 according to the embodiment of the present invention will be described with reference to FIG. 2 and subsequent drawings as appropriate. FIG. 2 is an external view showing the entire measurement probe 1 according to the embodiment of the present invention.

Figure 3 is a cut end view of the measurement probe shown in Figure 2 cut in the longitudinal direction. Figure 4 is an enlarged explanatory diagram showing the portion surrounded by the dashed line in the configuration diagram of the measurement probe 1 in Figure 3.

In addition, both Fig. 2 and Fig. 3 show a double-headed arrow along the longitudinal direction of the measurement probe 1. This arrow indicates the movement direction of the plunger 2, which will be described later. For convenience, the direction in which the pair of plungers 2, 2 move away from each other will be referred to as the "outside" direction. On the other hand, the direction in which the pair of plungers 2, 2 move toward each other will be referred to as the "inside" direction.

The longitudinal center of the pair of plungers 2, 2 will be referred to as "axis S" below, as appropriate, and is shown by a dashed line in Figures 2 and 3. The direction perpendicular to the longitudinal direction of the measurement probe 1 will be referred to as the short side. In the short side direction, the side closer to the axis S will be referred to as the inside, and the opposite side will be referred to as the outside.

As shown in FIG. 2 or FIG. 3, the measurement probe 1 in the embodiment of the present invention includes a plunger 2, an elastic member 3, and a barrel 4. The plunger 2 electrically connects the object to be measured to the tester by contacting an electrode of the object to be measured or an electrode provided on the upper surface of the interposer 30. In the measurement probe 1 in the embodiment of the present invention, the pair of plungers 2, 2 are arranged so that they face in opposite directions.

In the following description, of the pair of plungers 2, 2, the plunger shown on the left side of the drawing will be referred to as one plunger 21, and the plunger shown on the right side of the drawing will be referred to as the other plunger 22. However, when referring to the one plunger 21 and the other plunger 22 together, they will be referred to as plunger 2 as appropriate.

The first end 21a of one of the plungers 21 protrudes from the top surface of the workpiece side probe holder 20. When the object to be measured is attached to the workpiece side probe holder 20, the first end 21a of the plunger 21 contacts the electrode of the object to be measured due to the action of the elastic member 3.

On the other hand, the first end 22a of the other plunger 22 of the plungers 2 protrudes from the bottom surface of the work-side probe holder 20. The first end 22a of the other plunger 22 comes into contact with the electrode of the interposer 30 due to the action of the elastic member 3.

The plunger 21 and the plunger 22 have the same function and structure, but are oriented differently. Therefore, the following description will be given using the plunger 21 as an example.

One of the plungers 21 has a first end 21a at a position protruding outward in the longitudinal direction. The first end 21a is in direct contact with an electrode of the object to be measured or an electrode of the interposer 30.

As shown in FIG. 3 or FIG. 4, one of the plungers 21 has an outer step 21b on its outer circumferential surface that projects outward in the short direction perpendicular to the longitudinal direction from the outer circumferential surface, and an inner step 21c that projects inward in the short direction from the outer circumferential surface. In other words, in terms of distance from the axis S, the distance of the outer step 21b in the short direction from the axis S is longer than the distance of the inner step 21c.

The second end 21d is formed at the end of one plunger 21 opposite the first end 21a, and at a position extending from the inner step 21c toward the other plunger 22. The contact member 5 is disposed near the second end 21d.

The plunger 2 having such a shape can move in either direction of the double arrow shown in FIG. 2 or FIG. 3, that is, in the longitudinal direction of the measurement probe 1. When the electrodes are not in contact with the first end 21a of one plunger 21 and the first end 22a of the other plunger 22, the plunger 2 protrudes outward in the longitudinal direction of the measurement probe 1 as shown in FIG. 2 or FIG. 3.

On the other hand, when an electrode comes into contact with the first end 21a of one plunger 21 or the first end 22a of the other plunger 22, the one plunger 21 or the other plunger 22 moves longitudinally inward so as to be housed inside the barrel 4.

The plunger 2 can move inward or outward in the longitudinal direction of the measurement probe 1 because the plunger 2 is biased in the longitudinal direction of the measurement probe 1 by the elastic member 3.

That is, the elastic member 3 is disposed between the pair of plungers so as to bias them in a direction separating them from each other. Any material may be used as the elastic member 3, but a spring, for example, is preferably used.

The elastic member 3 is also formed so that it can withstand the load when the plunger 2 comes into contact with the electrode of the object to be measured. However, the elastic member 3 in this embodiment of the present invention does not have the function of contributing to the flow of current from one plunger 21 to the other plunger 22.

In other words, unlike the coil springs used in conventional probes, the coil spring does not come into contact with the inner wall of the barrel, allowing the probe as a whole to function as a conductor.

In the conventional probes described above, when the tubular conductor comes into contact with the electrode of the object to be measured and is pushed into the barrel, the coil spring comes into contact with the inner wall of the barrel, thereby establishing electrical continuity with the tester. However, this has the disadvantage that the value of the contact resistance is not stable.

The role of ensuring electrical continuity between the object to be measured and the tester is played by the contact member 5 described below, and the elastic member 3 in the embodiment of the present invention only plays the role of receiving the load of the object to be measured described above, and does not play the role of ensuring electrical continuity.

The elastic member 31 is separated into an elastic member 32 that biases the plunger 21 outward in the longitudinal direction and an elastic member 32 that biases the plunger 22 outward in the longitudinal direction, and is configured to be shorter in length than conventional coil springs. By adopting such a structure, it is possible to prevent the spring from bending and coming into contact with the inner wall surface of the barrel 4 even when it comes into contact with the electrodes of the object to be measured and receives a load.

Even if the plunger 2 is pushed in by contact with the electrode in this way and a load is applied to the elastic member 3, the length of the elastic member 3 is short, so the amount of deflection can be reduced and contact with the inner wall surface of the barrel 4 can be avoided as much as possible.

In addition, even if the elastic member 3 comes into contact with the inner wall surface of the barrel 4 when the plunger 2 is pushed into the barrel 4, as in the case of a conventional coil spring, the elastic member 3 is made of an insulating material so that no contact resistance occurs at the contact point between the two.

In addition, since the elastic member 3 only needs to receive the load and provide the plunger 2 with a force that can move the plunger 2 in the longitudinal direction of the measurement probe 1, the material can be selected with this point in mind. Specifically, it becomes possible to select a thinner wire material than that used for conventional coil springs.

The barrel 4 accommodates a part of the plunger 2, the elastic member 3, the contact member 5 (described later), and the ball 6 inside. The barrel 4 has an opening at one end 4c and an opening at the other end 4d on both ends in the longitudinal direction, and is formed in a cylindrical shape.

Because the barrel 4 is formed in this shape, one plunger 21 can be positioned to protrude from one end 4c, and the other plunger 22 can be positioned to protrude from the other end 4d, as shown in FIG. 2.

In the measurement probe 1 in FIG. 2, the outer peripheral surface 4a of the barrel 4 is shown, and in FIG. 3 and FIG. 4, the inner wall surface 4b of the barrel 4 is shown. When the plunger 2 is not pushed into the barrel 4, as shown in FIG. 3, the outer step 21b of one plunger 21 contacts one end 4c of the barrel 4, and the outer step 22b of the other plunger 22 contacts the other end 4d of the barrel 4.

In other words, the elastic member 3 biases the first plunger 21 and the second plunger 22 outward in the longitudinal direction of the measurement probe 1, but one end 4c contacts the periphery of the outer step 21b, and the other end 4d contacts the periphery of the outer step 22b, thereby preventing the first plunger 21 and the second plunger 22 from coming off the barrel 4 to the outside.

In addition, the short-side distance from the axis S of the outer peripheral surface 21e of one plunger 21, or the short-side distance from the axis S of the outer peripheral surface 22e of the other plunger 22, is shorter than the short-side distance from the axis S of the inner wall surface 4b of the barrel 4, even in the part with the largest value. Therefore, the parts of the one plunger 21 and the other plunger 22 housed inside the barrel 4 (particularly the outer peripheral surface 21e or the outer peripheral surface 22e) can move in the longitudinal direction of the measurement probe 1 without coming into contact with the inner wall surface 4b of the barrel 4 inside the barrel 4.

The contact member 5 is provided inside the barrel 4 to allow current to flow between the object to be measured and the tester. Specifically, as shown in FIG. 4, the outer casing 52 of the contact member 5 is arranged so as to contact the inner step 21c of one of the plungers 21 and the inner wall surface 4b of the barrel 4. By arranging the contact member 5 in this manner, it becomes possible for a current to flow from the electrode of the object to be measured, which the first end 21a of one of the plungers 21 contacts, to the tester side via the contact member 5 and the inner wall surface 4b of the barrel 4.

Here, FIG. 5 is an enlarged cross-sectional view showing the state cut along line A-A in the external view of FIG. 2. Therefore, the second end 21d of one of the plungers 21 is visible in the very center, and the inner step 21c is visible around it. However, since the contact member 5 is in contact with the inner step 21c as also shown in FIG. 4, only a portion of the inner step 21c is visible.

As shown in FIG. 5, the contact member 5 in the embodiment of the present invention is made of a conductive material and is formed in a substantially C-shape with two open ends 51, 51. The outer casing 52 of the contact member 5 is in contact with the inner wall surface 4b of the barrel 4.

As shown in FIG. 4, when the contact member 5 is housed inside the barrel 4, the plunger 21 contacts the inner step 21c, and the plunger 22 contacts the elastic member 3.

In this way, the contact member 5 is in contact with the inner step 21c of one of the plungers 21, and the outer casing 52 of the contact member 5 is in contact with the inner wall surface 4b, so that a current can flow from the object to be measured to the tester.

In addition, since it is positioned between the inner step 21c of one of the plungers 21 and the elastic member 3, it moves in the longitudinal direction of the measurement probe 1 following the movement of the other of the plungers 21.

Thus, although the contact position on the inner wall surface 4b of the barrel 4 changes as one of the plungers 21 moves, it is possible to prevent the contact resistance from changing significantly because it is always in contact with the inner wall surface 4b.

As described above, the outer shell 52 of the contact member 5 is in contact with the inner wall surface 4b of the barrel 4. In other words, the distance from the axis S in the short side direction of the contact member 5 is longer than the distance from the axis S in the short side direction of one of the plungers 21, and it protrudes outward in the short side direction. Therefore, it is difficult to position the contact member 5 inside the barrel 4.

However, as shown in FIG. 5, the contact member 5 is formed in a roughly C-shape and has two open ends 51, 51. Therefore, when placing the contact member 5 inside the barrel 4, the open ends 51, 51 can be moved closer to each other and slightly reduced in distance from the short axis S, allowing for smooth placement.

Next, as shown in FIG. 3, a ball 6 is disposed inside the barrel 4, approximately in the center. The ball 6 is formed into a spherical shape from a conductive material. In addition, since the ball 6 is pressed into the barrel 4, it is in contact with the inner wall surface 4b of the barrel 4 over its entire circumference.

By arranging the conductive ball 6 in such a position, the current can flow smoothly from one plunger 21 to the other plunger 22, and the contact resistance can be prevented from changing.

As described above, in order to prevent the plunger 2 from bending and contacting the inner wall surface 4b when it is pushed into the barrel 4, the elastic member 3 in the embodiment of the present invention is divided into an elastic member 31 that biases one plunger 21 and an elastic member 32 that biases the other plunger 22.

As shown in FIG. 3, one end of the elastic member 3 is in contact with the contact member 5. The other end is in contact with the ball 6. By arranging the ball 6 in the approximate center inside the barrel 4 in this manner, the length of the elastic member 3 can be shortened so that it does not come into contact with the inner wall surface 4b of the barrel 4 even when it bends, without impeding the flow of current in the measurement probe 1.

The measurement probe 1 in the embodiment of the present invention employs the structure described above, which allows for more accurate evaluation of the object being measured by stabilizing the contact resistance value with a simple structure while maintaining the functionality of previous probes.

The present invention is not limited to the above-described embodiment, but is merely one example of the present invention. In the implementation stage, the components can be modified without departing from the gist of the invention, and various modifications and improvements can be made to the above-described embodiment. Furthermore, various inventions can be created by appropriately combining multiple components disclosed in the above-described embodiment.

For example, some components may be deleted from all of the components shown in the embodiment. Furthermore, components across different embodiments may be combined as appropriate, and such modified or improved forms may also be included in the present invention. These embodiments and their variations are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

In the embodiments described so far, the contact member 5 has been formed in a roughly C-shape. However, any shape is acceptable as long as it can contact the inner wall surface 4b of the barrel 4 and establish electrical continuity from one plunger 21 to the other plunger 22 in the measurement probe 1.

Therefore, two examples of contact members 5 with different shapes are given below. Figure 6 is a partially enlarged view showing another embodiment of a measurement probe 1 according to an embodiment of the present invention. Also, Figure 7 is a partially enlarged view showing yet another embodiment of a measurement probe 1 according to an embodiment of the present invention.

As in the previous sections, in Figures 6 and 7, one of the plungers 21 will be used as an example for explanation, and the portion shown in the drawing, like Figure 4, indicates the area indicated by the dashed line in Figure 3.

In addition, the shape of one of the plungers 21 does not have the inner step 21c as described above. Of course, one of the plungers 21 with the inner step 21c may also be used.

In the embodiment shown in FIG. 6, the contact member 5A has a protruding portion 5A1 between the first end 21a and the second end 21da of one of the plungers 21, protruding from the outer circumferential surface 21e of the one of the plungers 21 and contacting the inner wall surface 4b of the barrel 4. This protruding portion 5A1 is made of a material through which an electric current can flow, and for example, contacts the inner wall surface 4b of the barrel 4 at at least two points around the entire circumference of the outer circumferential surface 21e.

In the contact member 5A shown in FIG. 6, the protrusions 5A1, 5A1 are in contact with the inner wall surface 4b at two points. The two protrusions 5A1, 5A1 are biased toward the outside in the short side direction by a biasing member (not shown) that is disposed inside one of the plungers 21 in the short side direction. Therefore, the protrusions 5A1, 5A1 are always in contact with the inner wall surface 4b.

The type of biasing member may be any type, such as a spring, as long as it can keep the protrusions 5A1, 5A1 in contact with the inner wall surface 4b of the barrel 4.

On the other hand, the contact member 5B shown in FIG. 7 is arranged so that one contact member 5B protrudes all around the outer circumferential surface 21e of one of the plungers 21, for example like an O-ring. Even if the contact member 5B has such a shape, it can be brought into contact with the inner wall surface 4b of the barrel 4. As explained above, the contact member 5B is made of a material that allows an electric current to flow.

In this way, even the contact members 5A and 5B as shown in Figures 6 and 7 can be kept in contact with the inner wall surface 4b of the barrel 4, and by stabilizing the contact resistance value with a simple structure while maintaining the functionality of the previous probes, it is possible to provide a measurement probe and a probe unit equipped with the measurement probe that enable more accurate evaluation of the object to be measured.

In the above-described embodiment of the present invention, the measurement probe 1 has been described on the assumption that the pair of plungers 2, 2 are arranged coaxially. However, the measurement probe is not limited to this structure, and for example, one plunger and the other plunger may be formed, for example, in an L-shape with a ball as a corner.

Although we have not yet explained the arrangement of the measurement probes 1, they are arranged in m rows and n columns (m>1, n>1). The number and positions of the measurement probes 1, the arrangement of m rows and n columns, and the pitch are designed according to the number and positions of the electrodes of the object to be measured.

The techniques described in the embodiments of the present invention may also be configured as follows.
(1) A pair of plungers, each having a first end portion in contact with an electrode facing in the opposite direction, the pair of plungers having an outer peripheral surface with an outer step portion protruding outward in a short side direction perpendicular to a longitudinal direction from the outer peripheral surface, and an inner step portion protruding inward in the short side direction from the outer peripheral surface;
an elastic member disposed between the pair of plungers so as to bias the plungers in directions separating them from each other;
a barrel having one end in contact with the outer step portion formed on one of the pair of plungers and the other end in contact with the outer step portion formed on the other of the pair of plungers so as to allow the pair of plungers to move in the longitudinal direction, and housing therein second ends of the pair of plungers opposite to the first ends and the elastic member;
a contact member arranged to contact the inner step portions of the pair of plungers and an inner wall surface of the barrel;
A measurement probe comprising:
(2) The measurement probe according to (1) above, wherein an outer periphery of the contact member protrudes outward in the short side direction beyond outer peripheries of the pair of plungers.
(3) The measurement probe according to (1) or (2) above, characterized in that in the plunger, the outer step portion is formed on the first end side and the inner step portion is formed on the second end side.
(4) The measurement probe according to any one of (1) to (3) above, wherein the elastic member is made of an insulating material.
(5) A measurement probe as described in any one of (1) to (4) above, characterized in that it is provided with a ball disposed inside the barrel, between the one plunger and the other plunger, in contact with the inner wall surface of the barrel.
(6) The measurement probe according to (5) above, wherein the ball is made of metal.
(7) The measurement probe according to (5) or (6) above, wherein one end of the elastic member contacts the contact member, and the other end of the elastic member contacts the ball.
(8) A measuring probe according to any one of (1) to (7) above;
a probe holder for holding the measurement probe and for mounting an object to be measured;
A connector terminal to be connected to a tester;
an interface probe holder that connects the probe holder and the connector terminal;
A probe unit comprising:

1: measuring probe, 2: plunger, 21: one plunger, 21a: first end, 21b: outer step, 21c: inner step, 21d: second end, 21e: outer periphery, 22: other plunger, 22a: first end, 22b: outer step, 22c: inner step, 22d: second end, 3: elastic member, 4: barrel, 4a: outer wall, 4b: inner wall, 5: contact member, 51: open end, 52: outer shell, 6: ball

Claims (8)

a pair of plungers arranged such that first ends in contact with the electrodes face in opposite directions, the pair of plungers having an outer circumferential surface with an outer step portion that projects outward in a lateral direction perpendicular to the longitudinal direction from the outer circumferential surface, and an inner step portion that projects inward in the lateral direction from the outer circumferential surface;
an elastic member disposed between the pair of plungers so as to bias the plungers in directions separating them from each other;
a barrel having one end in contact with the outer step portion formed on one of the pair of plungers and the other end in contact with the outer step portion formed on the other of the pair of plungers so as to allow the pair of plungers to move in the longitudinal direction, and housing therein second ends of the pair of plungers opposite to the first ends and the elastic member;
a contact member arranged to contact the inner step portions of the pair of plungers and an inner wall surface of the barrel;
A measurement probe comprising: The measurement probe according to claim 1, characterized in that the outer periphery of the contact member protrudes outward in the short direction beyond the outer periphery of the pair of plungers. The measurement probe according to claim 1, characterized in that the outer step is formed on the first end side of the plunger, and the inner step is formed on the second end side. The measurement probe according to claim 1, characterized in that the elastic member is made of an insulating material. The measurement probe according to claim 1, characterized in that it is provided with a ball disposed inside the barrel, between the one plunger and the other plunger, in contact with the inner wall surface of the barrel. The measurement probe according to claim 5, characterized in that the ball is made of metal. The measurement probe according to claim 5, characterized in that one end of the elastic member contacts the contact member and the other end of the elastic member contacts the ball. A measuring probe according to any one of claims 1 to 7,
a probe holder for holding the measurement probe and for placing an object to be measured thereon;
A connector terminal to be connected to a tester;
an interface probe holder that connects the probe holder and the connector terminal;
A probe unit comprising:

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