KR100659944B1 - A plunger and a probe employing that - Google Patents

Abstract

A plunger and a probe having the same are provided to stably contact the plunger against a barrel when an axial force is applied to the plunger, thereby achieving uniform inspection performance. A plunger includes plural probe projections(110) on the outer end thereof, and resiliently moves into/from a barrel(200). The height difference between the longest probe projection(111) having the longest protruding length and the shortest probe projection(112) having the shortest protruding length is in a range of 0.025 to 0.1mm. The probe projection has a recessed groove(120), and the recessed groove is radially formed from the center portion of the outer end of the plunger.

Description

Plunger and inspection probe equipped with it {a plunger and a probe employing that}

1-a longitudinal sectional view showing one embodiment of a probe for inspection according to the prior art;

Figure 2 is a longitudinal sectional view of the main portion showing another embodiment of the inspection probe device according to the prior art.

Figure 3 is a longitudinal sectional view of the main part showing another embodiment of the inspection probe device according to the prior art.

Figure 4-Longitudinal sectional view showing an embodiment of the inspection probe device according to the present invention.

Figure 5-Longitudinal sectional view showing another embodiment of the inspection probe device according to the present invention.

Figure 6-Bottom view of Figure 5;

7-5 are longitudinal sectional views showing the operation of FIG.

8-Graph showing Table 1 graphically.

Figure 9-Graph showing Table 2 graphically.

<Description of Major Symbols Used in Drawings>

10: Test object contact terminal 20: PCB contact terminal

100: plunger 100a: flat plate contact plunger

100b: ball contact plunger 110: probe protrusion

110a: plate contact projection 111: longest projection

111a: Plate contact longest projection 112: Shortest projection

112a: plate contact shortest projection 113: intermediate projection

113a: plate contact intermediate protrusion 120: recessed groove

200: barrel 300: elastic spring

500: inspection probe device

The present invention relates to a plunger and an inspection probe device equipped with the same, and more particularly, to a plunger having a plurality of probe protrusions having different protruding lengths on an outer end thereof, and an inspection probe device equipped with the same.

In general, a plurality of chips are mounted in an electronic product, and these chips play an important role in determining the performance of the electronic product. Chips are integrated circuits that perform various functions due to logic elements formed on the surface of thin and small pieces of semiconductors, and electrical signals transmitted from circuit boards are transmitted through a bus to accomplish this function.

A printed circuit board (PCB) is a thin board made of epoxy or bakelite resin, which is an insulator, and is formed by applying copper as a conductor to form circuit wiring. It is attached to this printed circuit board by soldering on circuit wiring.

Micro-chip is a chip made by high density integration of electronic circuits of such circuit boards, and it is essential to check the process by an inspection device to check whether the chip is in a normal state before it is assembled and completed. It goes through.

In this test method, there is a method of performing a test by mounting a chip to a test socket device, and a test probe device is used to check the chip without damaging the chip in the socket device.

The inspection socket is mounted on the inspection circuit board so that the microchip, which is the inspection object, is placed on the inspection circuit, and the inspection socket is mounted, and the inspection socket is equipped with a plurality of inspection probes to contact the microchip.

An electric current flows from the upper end of the probe device in contact with various points of the microchip for inspection to the circuit board side through the contact pins of the probe body and the lower end of the probe, thereby inspecting the chip for inspection.

1 is a longitudinal cross-sectional view of a conventional general inspection probe device 105, the upper and lower openings and both ends are in contact with the inner cylinder inner wall surface at both ends of the outer cylinder 111 formed with a bent portion is bent inward to flow up and down A pair of contact pins 117 are accommodated, and the coil spring 121 contacts the ends of the pair of contact pins 117 in the outer cylinder so that the contact pins 117 can be elastically supported. It is.

However, the inspection probe for the structure as described above is easy to pass only the coil spring 121 having a narrow cross-sectional area until the current transmitted to the upper contact pin 117 to the lower contact pin 117, In this case, the contact resistance is increased by the narrow contact area between the coil spring 121 and the contact pin 117.

In addition, as the contact pins 117, the outer cylinder 111, and the coil spring 121 are unstable in contact with each other, as well as the individual probe devices having a slight difference in processing accuracy, the resistance value of each probe may be the same. There was a problem that is generated differently.

In order to solve this problem will be briefly described the ELECTRICAL CONTACT of the US Patent No. 3,435,168 as a prior art devised to solve this problem.

The prior art is inclined to form a contact surface 84 with the spring 85, as shown in Figure 2, or as shown in Figure 3 via the metal ball (88, 90) as a medium In an embodiment in which the plunger 16 is electrically connected, for example, the plunger 16 is allowed to come into contact with the outer cylinders 8 and 10 while being inclined naturally when subjected to the axial pressing force.

However, in order to fabricate the probe shown in FIG. 2, a highly difficult process of forming an inclined surface of a predetermined slope on the inner surface of the plunger 16 is additionally required, and the spring 85 or the plunger 16 is additionally required. ) As the pressing and releasing states are repeated, the vanes are turned and the ends of the outer cylinders 8 and 10 are scratched and damaged.

In addition, in manufacturing the probe illustrated in FIG. 3, as the process of separately manufacturing and inserting a plurality of metal balls 88 and 90 is additionally required, the assembly process becomes more cumbersome and the manufacturing cost increases.

In addition, the structure as described above is easy to maintain the inclined form even when the plunger 16 is not being subjected to an axial direction, and it is difficult to grasp whether it is defective or damaged, and the collective mounting to the socket is not easy. There was another problem.

An object of the present invention is to provide a plunger having a structure capable of realizing a uniform inspection performance while reducing the resistance generated during the inspection test, and an inspection probe device equipped with the same. It is done.

In addition, when the axial pressing force is applied, the plunger can be inclined stably and does not damage the outer cylinder, and is easy to process, and does not have to be additionally provided, thereby improving productivity and providing a low cost unit. Another object is to provide an inspection probe equipped with the same.

The present invention for achieving the object as described above, in the plunger having a plurality of probe projections at the outer end to elastically flow in and out of the barrel, the probe projections, the longest projection having the longest projection length, the shortest projection length Plunger characterized in that the shortest protrusion having a height difference of more than 0.025mm 0.1mm or less as the technical gist.

Here, the probe projection is formed radially and the recessed groove is formed around the position spaced apart from the center of the outer end of the plunger is formed, the embodiment having a number of three to eight or less desirable.

In addition, another technical gist of the inspection probe device provided with the plunger is preferable, and the plunger preferably includes another embodiment installed at one side or both sides of the barrel.

Therefore, when the axial pressing force is applied, the plunger is naturally inclined and the contact with the barrel is made stable, thereby reducing the resistance generated during the test and achieving the uniform test performance.

In addition, there is another advantage that it is easy to process, there is no need to additionally produce and assemble a separate configuration to further improve productivity and provide a low cost.

In addition, there is another advantage that it is clearly distinguished and operated according to the action of the axial pressing force to facilitate assembly and mounting to the socket.

In addition, the stable connection with the elastic spring is maintained even when the plunger is tilted, so that the plunger pushed against the end of the elastic spring or the pressing force of the elastic spring can prevent the plunger from turning and damaging the barrel inner wall while being pressed. have.

The present invention having the configuration as described above will be described in detail with reference to the following drawings. Figure 4 is a longitudinal cross-sectional view showing an embodiment of the inspection probe according to the present invention, Figure 5 is a longitudinal sectional view showing another embodiment of the inspection probe according to the invention, Figure 6 7 is a longitudinal sectional view showing the operation of FIG.

The plunger 100 according to the present invention is elastically flowed in and out of the barrel 200 while a part of the barrel 200 is restrained, and in the plunger having a plurality of probe protrusions 110 at an outer end thereof, the By forming the protruding length of the probe protrusion 110 differently, the protruding length of the probe 110 has a configuration in which the protruding length is naturally inclined toward one side.

The probe protrusion 110 is in direct contact with the contact terminal 10 of the inspection object or the contact terminal 20 of the PCB circuit board as it is positioned at the end of the plunger 100 and the inspection probe device 500 for inspection. You lose.

Thus, the probe protrusion 110 has been formed with a constant protrusion height of a number having a pointed shape in which the cross-sectional area is generally narrowed toward the distal end so that the contact with the contact terminals 10, 20 can be made clearly. .

In the present invention, the longest protrusion 111 having the longest protrusion length and the shortest protrusion 112 having the shortest protrusion length are respectively formed on one side and the other side, and a plurality of different probe protrusions 110 are interposed therebetween. It has a structure formed with a protruding length corresponding to the extension line of the distal end of the protrusion 111 and the shortest protrusion (112).

The plunger 100 is inclined while being partially constrained to the barrel 200 formed in a cylindrical shape having an upper and lower open sides. When the height difference z between the longest protrusion 111 and the shortest protrusion 112 is small, If the plunger 100 does not stably contact the barrel 200, and the height difference z between the longest protrusion 111 and the shortest protrusion 112 is excessive, the plunger 100 may cause the barrel 200. It is preferable to limit the height difference z within a certain range because it may damage the.

The cross-sectional size of the plunger 100 and the inner diameter of the barrel 200 are organically related to each other along with each surface state to generate contact resistance, and the sizes of the plunger 100 and the barrel 200 Since it is practically difficult to grasp the precise pattern of contact resistance by limiting, in the present invention, the longest protrusion 111 and the shortest protrusion 112 are based on the experiments corresponding to Tables 1 and 2 described below. The height difference z is defined to be 0.025 mm or more and 0.1 mm or less.

The probe protrusion 110 has a radial shape centering on a position spaced apart from the center of the outer end of the plunger 100, and cutting the V-shaped recessed groove 120 radially separated probes between radially separated. Protrusion 110 is formed, the protruding length is not uniform.

When cutting is formed as described above, the longest protrusion 111 is formed at the position having the longest length from the center, and the shortest protrusion 112 is formed at the position having the shortest length from the center, and the longest protrusion 111 is formed. And the probe protrusion 110 positioned between and the shortest protrusion 112 naturally have a protruding length having an end extending from the end of the longest protrusion 111 and the shortest protrusion 112.

Accordingly, when the plunger 100 is inclined such that the shortest protrusion 112 is in contact with a contact terminal having a flat contact surface, not only the longest protrusion 111 and the shortest protrusion 112 but also a plurality of other probe protrusions 110. They also naturally come into contact with the contact terminal, so that all of the plurality of the protruding protrusions 110 are in contact with the contact terminal to implement a clear electrical connection.

Each of the probe protrusions 110 is formed by radially cutting the recessed grooves 120, and the size and position of the set area at each position separated by the recessed grooves 120, of the recessed grooves 120 Depending on the depth and size, it can be formed in various forms within the number range of three to eight.

4 is a longitudinal sectional view showing an embodiment of the present invention in which the plunger 100 according to the present invention is installed at upper and lower ends of the barrel 200, and FIG. 5 is a contact terminal 10 of a hemispherical inspection object. A flat plate having a structure according to the present invention is provided only at an end portion in which the ball contact plunger 100b having a probe protrusion having a constant protrusion height is provided at the upper end thereof, and the contact with the PCB substrate having the flat contact terminal 20 is made. It is a longitudinal cross-sectional view which shows another Example which provided the contact plunger 100a.

The present invention is not only the plunger 100, but also the inspection probe device 500, in which the plunger 100 is installed, as shown in FIGS. It is to be understood that the present invention is not limited to the same structure and includes all the inspection probes 500 having various structures in which the plunger 100 is installed.

According to the embodiment of the present invention as described above, in implementing the operating principle to tilt the plunger 100 by the pressing force in the axial direction, such as the elastic spring 300 inside the barrel 200 It can be seen that there is no need to add any additional components besides the components.

In the above embodiment, a total of four probe protrusions 110 is formed, including the longest protrusion 111 (a), the shortest protrusion 112 (a), and two other intermediate protrusions 113 (a). As shown in FIG. 6, when four (or two) recessed grooves 120 (the dotted marks of the lower V-shaped 120a) are formed at right angles with respect to the positions spaced from the center (*), It can be produced in the same shape as the above embodiment.

Table 1 below summarizes the experimental data measured the resistance value as an embodiment of the inspection probe according to the prior art shown in Figure 1, Table 2 below the present invention shown in Figure 5 In the embodiment of the inspection probe according to the present invention is summarized the experimental data measured the resistance value, Figure 8, 9 is a graph showing the experimental data corresponding to the contents of [Table 1] and [Table 2], respectively.

The experimental data in Table 1 show that the total length of the inspection probe is 5.7 mm, the length of the outer cylinder is 4 mm, the thickness of the outer cylinder is 0.09 mm, and the diameter of the outer end of the plunger is 0.3 mm. The measured values of resistance (unit: mΩ) were recorded 10 times with 33 samples which were formed uniformly.

The experimental data in Table 2 is similar to the above Table 1, where the total length of the inspection probe is 5.7 mm, the barrel length is 4 mm, the barrel thickness is 0.09 mm, and the plunger outer end diameter is 0.3 mm. The measured values of resistance (unit: mΩ) were recorded 10 times with 32 samples having the protruding length difference (z) of the longest protrusion 111 and the shortest protrusion 112 as 0.025 mm.

The number on the leftmost column of each row corresponds to the sample number and the number on the top of each column corresponds to the measurement interval.

In Table 1, the maximum resistance is 277.2 mΩ, the minimum resistance is 27.2mΩ, the average resistance is 71.09mΩ, and the standard deviation between resistances is 46.36.

In Table 2, the maximum resistance value is 168.5mΩ, the minimum resistance value is 20.3mΩ, the average resistance value is 41.33mΩ, and the standard deviation between resistance values is 19.24.

It can be seen that the content of Table 2 is significantly lower than the standard resistance between the average resistance value and the resistance value compared to the content of Table 1, which means that the plunger 100 and the inspection probe 500 equipped therewith according to the present invention are It supports the excellent effect of reducing the resistance and achieving uniform inspection performance.

According to the present invention, the plunger 100 is naturally inclined when contacting an object having a flat contact surface, the barrel 200 is contacted, and the inspection reliability can be further improved by extending the current path. Even when implementing the structure, there is no need to add additional components, thereby maintaining existing productivity and cost.

When the axial pressing force is applied, the plunger 100 is inclined in contact with the contact terminal, but when the pressing force is released and spaced apart from the contact terminal, the original form is returned to its initial form, depending on whether the pressing force is applied. As it is clearly distinguished operation, it is easy to grasp the breakage of the plunger 100 and the like, and it is easy to collectively install the socket.

In addition, even when the plunger 100 is inclined, as the stable connection state with the elastic spring 300 is maintained, the end portion of the elastic spring 300 is not constrained to a specific position so that the elastic spring 300 or An end portion of the plunger 100 pushed by the pressing force of the elastic spring 300 does not occur while turning around the barrel 200 while pressing the inner wall.

The present invention by the configuration as described above, the plunger is naturally inclined when the axial pressing force is applied and the contact with the barrel is made stable to further reduce the resistance generated during the test and to implement a uniform test performance It can be effective.

In addition, it is easy to process, there is no need to additionally produce and assemble a separate configuration has another effect that can be more improved productivity and at a lower cost.

In addition, according to the action of the axial pressing force is clearly distinguished operation has another effect that the assembly and mounting to the socket is easy.

In addition, the stable connection with the elastic spring is maintained even when the plunger is tilted, so that the plunger pushed against the end of the elastic spring or the pressing force of the elastic spring can prevent the plunger from turning and damaging the barrel inner wall while pressing. have.

Claims (6)

In the plunger elastically flows in and out of the barrel having a plurality of probe projections on the outer end, The probe projection is, A plunger characterized by having the longest protrusion having the longest protrusion length and the shortest protrusion having the shortest protrusion length having a height difference of 0.025 mm or more and 0.1 mm or less. The method of claim 1, wherein the probe protrusion, A plunger which is radially formed around a position spaced apart from the center of the outer end of the plunger, and a recess is formed by cutting. The method of claim 1 or 2, wherein the probe protrusion, A plunger characterized by having a number of three to eight. The inspection probe device of claim 1, wherein the plunger is installed. The method of claim 4, wherein the plunger is Inspection probe device, characterized in that installed only on one side of the barrel. The method of claim 4, wherein the plunger is Inspection probes, characterized in that installed on both sides of the barrel.

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