Pogo Pin for High Voltage Having Shorter Diameter

Abstract

A pogo pin according to the present invention is a pogo pin in which a first connecting leg of a first plunger is inserted through one side of a coil spring and a second connecting leg of a second plunger is inserted through the other side of the coil spring, and the first connecting leg and the second connecting leg can slide while in contact with each other, wherein, prior to the first connecting leg and the second connecting leg being inserted into the coil spring, the coil spring has one or more axial sections having a reduced inner diameter at an intermediate position in the longitudinal direction, and when the first connecting leg and the second connecting leg are inserted into the axial section, the axial section is deformed or expanded.

Description

Technology Field

[0001] The present invention relates to a pogo pin, and also to a pogo pin primarily used for transmitting high-voltage power and signals. Background Technology

[0002] Patent Document 1 is a technology relating to an inner bridge type spring probe pin (pogo pin) previously filed by the inventor of the present application, and the technology of Patent Document 1 is characterized by having a structure in which the connecting leg portions on both sides are in contact and can slide through a cylindrical space inside the coil spring.

[0003] However, the more stable the contact between the two connecting legs and the larger the actual contact area, the more advantageous it is for transmitting high voltage and high current. To achieve this, one could consider using coil springs to tightly tighten the two connecting legs, but in this case, the operation (sliding) of the two connecting legs would not be smooth, and in severe cases, a jam would occur, leading to other problems. Therefore, a method is required that allows for smooth operation (sliding) of the connecting legs while being advantageous for transmitting high voltage and high current.

[0004] Meanwhile, Patent Document 1 provides an external contact portion for electrical contact with the outside, and the external contact portion is formed such as a cylindrical crown having a plurality of contact points, a flat blade having a single contact point, or a flat plate having two or more contact points.

[0005] Cylindrical crowns usually have four horns (contact points), but due to manufacturing reasons, there are often slight differences in the height of each horn, so only some of the horns make contact. When pogo pins are applied in a high-voltage environment, the fact that only some of the horns make contact can cause problems such as sparking or burning.

[0006] Meanwhile, as shown in FIG. 3 or FIG. 4 of Patent Document 1, both ends of the coil spring are positioned in a concave groove between a hook and a stopper and are caught using a hook. In order to prevent the ends of the coil spring from slipping out of the groove, the inner diameter of both ends of the coil spring is usually made smaller, and the gap between adjacent turns is narrowed compared to other parts.

[0007] For these reasons, there is a problem where the maximum stroke of the pogo pin decreases because it is difficult for the end of the opposite connecting leg to pass through the end of the coil spring and move further. In particular, when the end of the opposite connecting leg reaches the end of the coil spring, the spring force increases rapidly, making it difficult to continue functioning as a pogo pin.

[0008] In addition, if the Max stroke is small, the range of overcoming minute height differences between tens to thousands of terminals (e.g., balls of a BGA) in a semiconductor device is limited, and in severe cases, problems may occur where the terminals (balls) are crushed when performing burn-in tests on the semiconductor device.

[0009] Since the analysis of the problems of the prior art described above is also part of the process leading to the present invention, the inventive step should not be determined by taking it for granted. Prior art literature

[0010] Republic of Korea Registered Patent 10-1525120, registered on May 27, 2015 The problem to be solved

[0011] The objective of the present invention is to provide a pogo pin that operates smoothly and has superior electrical transmission capability through the connecting bridge.

[0012] In addition, another objective of the present invention is to provide a pogo pin having a more superior and stable external contact with better electrical transmission capability.

[0013] In addition, another objective of the present invention is to provide a pogo pin with a more extended maximum stroke. means of solving the problem

[0014] A pogo pin according to one aspect of the present invention is a pogo pin in which a first connecting leg of a first plunger is inserted through one side of a coil spring and a second connecting leg of a second plunger is inserted through the other side of the coil spring, and the first connecting leg and the second connecting leg can slide while in contact with each other, wherein before the first connecting leg and the second connecting leg are inserted into the coil spring, the coil spring has one or more axial sections having a reduced inner diameter at an intermediate position in the longitudinal direction, and when the first connecting leg and the second connecting leg are inserted into the axial section, the axial section is deformed or expanded.

[0015] In the pogo pin described above, in claim 1, the inner diameter of the shaft section before the first connecting leg and the second connecting leg are inserted into the coil spring may be smaller than the outer diameter of the part where the first connecting leg and the second connecting leg come into contact with each other.

[0016] In the above-described pogo pin, the first connecting leg is eccentrically positioned in one direction from the vertical axis of the coil spring, and the second connecting leg may be eccentrically positioned in the opposite direction from the vertical axis of the coil spring.

[0017] In the above-described pogo pin, when the first connecting leg and the second connecting leg are inserted into the shaft section, the shaft section may be compressed from a circular shape into an elliptical shape.

[0018] In the above-described pogo pin, the coil spring is formed with a first shaft diameter section, which is one of the shaft diameter sections, and a second shaft diameter section, which is another of the shaft diameter sections, respectively, wherein the first shaft diameter section and the second shaft diameter section may be formed spaced apart from each other.

[0019] In the above-described pogo pin, when the pogo pin is in operation, each of the first shaft diameter section and the second shaft diameter section may tighten the portion where the first connecting leg and the second connecting leg overlap.

[0020] In the above-described pogo pin, an external contact portion for electrical contact with the outside is formed on the opposite side of the first connecting leg in the first plunger, wherein the external contact portion is configured to include a plurality of probes, and each of the probes may be elastically bent after contacting an external contact surface at different points.

[0021] In the above-described pogo pin, each of the probes may be curved such that one end is connected to a cylindrical part and, as it moves toward the free end, it converges toward the central axis of the cylindrical part.

[0022] In the above-described pogo pin, the free end may start contacting the outer contact surface at a contact angle of 45 degrees or less, and then the contact angle may gradually decrease as pressure is applied.

[0023] A pogo pin according to one aspect of the present invention is a pogo pin in which a first connecting leg of a first plunger is inserted through one side of a coil spring and a second connecting leg of a second plunger is inserted through the other side of the coil spring, and the first connecting leg and the second connecting leg can slide while in contact with each other, wherein the first connecting leg has a first projection formed by expanding its outer diameter at an intermediate position in the longitudinal direction, and the coil spring has a first axial diameter section having a reduced inner diameter at an intermediate position in the longitudinal direction, wherein the outer diameter of the first connecting leg at the part where the first projection is located is larger than the inner diameter of the first axial diameter section.

[0024] In the above-described pogo pin, the first projection located inside the first shaft section may not be able to slide over the first shaft section and slip out due to the force caused by the weight of the first plunger.

[0025] In the above-described pogo pin, the first projection is provided with a first slope facing inward and a second slope facing outward, wherein the first slope may have a gentler slope than the second slope.

[0026] In the above-described pogo pin, in the above-described coil spring, a first expansion section having an inner diameter larger than the inner diameter of the first axial section is formed between one end of the coil spring and the first axial section, and when the pogo pin is operated, the first expansion section may be capable of compression and expansion.

[0027] In the above-described pogo pin, when inserted into the first shaft diameter section, the first connecting leg can deform or expand the first shaft diameter section.

[0028] In the above-described pogo pin, the second connecting leg has its outer diameter expanded at an intermediate position in the longitudinal direction to form a second projection, and the coil spring has a second axial diameter section having a reduced inner diameter at an intermediate position in the longitudinal direction, wherein the outer diameter of the second connecting leg at the part where the second projection is located may be larger than the inner diameter of the second axial diameter section.

[0029] In the above-described pogo pin, the first plunger is provided with a first stopper that supports one end of the coil spring, but there is no hook for hooking the one end of the coil spring, and the second plunger is provided with a second stopper that supports the other end of the coil spring, but there is no hook for hooking the other end of the coil spring.

[0030] In the above-described pogo pin, the coil spring comprises: a first expansion section located between one end of the coil spring and the first axial section, with an inner diameter larger than that of the first axial section; a second expansion section located between the other end of the coil spring and the second axial section, with an inner diameter larger than that of the second axial section; and a third expansion section located between the first axial section and the second axial section, with an inner diameter larger than that of the first axial section and the second axial section, wherein when the pogo pin is actuated, all of the first expansion section, the second expansion section, and the third expansion section may be capable of compression and extension.

[0031] In the above-described pogo pin, the inner diameter of the third enlarged section is equal to or larger than the outer diameter of the first connecting leg in the part where the first protrusion is located, and may be equal to or larger than the outer diameter of the second connecting leg in the part where the second protrusion is located. Effects of the invention

[0032] According to the pogo pin of the present invention, there is an effect of smooth operation and superior electrical transmission capability through the connecting legs. The pair of connecting legs is tightened with a force such that the shaft diameter is relatively constant and no jamming occurs, thereby allowing the two connecting legs to maintain stable contact.

[0033] According to the pogo pin of the present invention, since the first axial section and the second axial section, which are spaced apart from each other, tighten the pair of connecting legs at two different points of the pair of connecting legs, it is easier for the two connecting legs to maintain contact over a wider area. Since they tighten at two spaced-apart points among the overlapping parts of the pair of connecting legs, it is effective to prevent the position of the pair of connecting legs from becoming misaligned, thereby preventing the contact area from becoming smaller or the contact from becoming linear.

[0034] According to the pogo pin of the present invention, the electrical transmission capability of the external contact portion is superior and stable. Even if there is a slight difference (height difference) due to processing reasons, the height difference is overcome during the process in which the probe is pressed and deformed, thereby enabling more probes or all probes to come into contact with the outside.

[0035] According to the pogo pin of the present invention, the maximum stroke is further extended. By utilizing the axial section that allows the two connecting legs to maintain stable contact by tightening the pair of connecting legs, the conventional hook can be eliminated. Brief explanation of the drawing

[0036] FIG. 1 is a perspective view illustrating a pogo pin according to a first embodiment of the present invention. FIG. 2 is an exploded perspective view illustrating a pogo pin according to a first embodiment of the present invention. FIG. 3 is a plan view illustrating a pogo pin according to a first embodiment of the present invention. FIG. 4 is a front view showing a coil spring in cross-section in a pogo pin according to the first embodiment of the present invention, FIG. 4(a) is in a free state and FIG. 4(b) is in a working state. FIG. 5 is a cross-sectional view showing the axial section of a pogo pin according to the first embodiment of the present invention, FIG. 5(a) is a hypothetical representation showing the size comparison of the connecting legs before inserting them into the coil spring, and FIG. 5(b) is after actually inserting the connecting legs into the coil spring. FIG. 6 is a cross-sectional view showing the axial section of a pogo pin according to a first variant of the present invention, where FIG. 6(a) is a hypothetical representation showing the size comparison of the connecting legs before inserting them into the coil spring, and FIG. 6(b) is after actually inserting the connecting legs into the coil spring. FIG. 7 is a side view illustrating the external contact portion and the cylindrical portion of a pogo pin according to the first embodiment of the present invention, where FIG. 7(a) is the free state, FIG. 7(b) is the working state, and FIG. 7(c) is the max state. FIG. 8 is a cross-sectional view illustrating the external contact portion and the cylindrical portion of a pogo pin according to the first embodiment of the present invention. FIG. 9 is a perspective view illustrating a pogo pin according to a second embodiment of the present invention. FIG. 10 is a disassembled perspective view of a pogo pin according to a second embodiment of the present invention. FIG. 11 is a front view showing a coil spring in cross-section in a pogo pin according to a second embodiment of the present invention, FIG. 11(a) is in a free state, FIG. 11(b) is in a working state, and FIG. 11(c) is in a max state. FIG. 12 is a cross-sectional view showing a comparison of the sizes of the connecting legs before they are inserted into the coil spring in a pogo pin according to a second embodiment of the present invention. FIG. 13 is a schematic diagram that clearly explains the inner diameter (outer diameter) of a coil spring used in the second embodiment of the present invention. Specific details for implementing the invention

[0037] Hereinafter, a pogo pin according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 5.

[0038] A pogo pin (1) according to the first embodiment of the present invention comprises a first plunger (10), a second plunger (20), and a coil spring (30).

[0039] Pogo pins (1) are used to form a socket for mounting semiconductor devices, and in a single socket, tens to thousands of pogo pins are arranged in an array, and one side of the pogo pins can be arranged to make electrical external contact with each pad of the semiconductor device and the other side can be arranged to make electrical external contact with a pad of a substrate such as a PCB.

[0040] The pogo pin (1) has a first connecting leg (11) of the first plunger (10) inserted through one side of the coil spring (30) and a second connecting leg (21) of the second plunger (20) inserted through the other side of the coil spring (30), and can slide with the first connecting leg (11) and the second connecting leg (21) in contact with each other.

[0041] The first plunger (10) is configured to include a first connecting leg (11), a first external contact part (12), a first cylindrical part (13), a first hook (14), a first stopper (15), and a first connecting part (16). The first plunger (10) can be manufactured by processing a single metal plate, punched according to the shape of a corresponding unfolded drawing, through bending and coining, and plating. Accordingly, the first connecting leg (11), the first external contact part (12), the first cylindrical part (13), the first hook (14), the first stopper (15), and the first connecting part (16) are connected to each other.

[0042] The first connecting leg (11) is in the shape of a bar that extends roughly in a straight line (hence also called a ‘sliding bar’) and is in the shape of a straight (linear) strip, having the thickness of a metal plate, and is punched into a long rectangular shape. The first connecting leg (11) is inserted into the cylindrical internal space of the coil spring (30) and slides relative to the second connecting leg (21) while in physical (hence electrical) contact, and the contact area (overlapping) with the second connecting leg (21) may vary depending on the compression and extension of the pogo pin.

[0043] Except for the area near the tip, the lateral width of the first connecting bridge (11) is mostly constant, at least within the section that can come into contact with the first axial section (31a) and the second axial section (32a).

[0044] The first external contact portion (12) is for electrical contact with the outside, such as a terminal (ball) of a semiconductor device or a pad of a PCB, and is formed on the opposite side (opposite end) of the first connecting leg (11) from the first plunger (10). The first external contact portion (12) is formed by a plurality (e.g., 6) of probes (12a) that extend from one end (outer end; hereinafter, the side further from the center in the longitudinal direction of the pogo pin is referred to as the 'outer side' and the side closer to the center in the longitudinal direction is referred to as the 'inner side') of the first cylindrical portion (13) and are connected (formed) along the circumference on the outside of the cylindrical portion (13).

[0045] The first cylindrical part (13) is formed by bending a metal plate into a cylindrical shape, with one end connected to the first connecting part (16) and the other end connected to a plurality of probes (first external contact part).

[0046] The first connecting part (16) connects the first connecting leg (11) and the cylindrical part (13), and may be formed as a band that is bent at a 90-degree angle from the outer end of the first connecting leg (11) and then bent again at a 90-degree angle in the opposite direction to connect the first connecting leg (11) and the first cylindrical part (13).

[0047] The first stopper (15) is a projection that protrudes laterally from the first connecting leg (11) near the outer end of the first connecting leg (11), and supports one end (one end) of the coil spring (30) so that the coil spring (30) (the end) does not slip outward.

[0048] The first hook (14) is a projection that protrudes laterally from the first connecting leg (11) slightly inside the first stopper (15), forming a small groove between it and the first stopper (15), allowing one end of the coil spring (30) to be seated in this groove, and preventing the seated one end of the coil spring (30) from slipping inward.

[0049] The second plunger (20) is configured to include a second connecting leg (21), a second external contact part (22), a second cylindrical part (23), a second hook (24), a second stopper (25), and a second connecting part (26). The second plunger (20) can be manufactured by processing a single metal plate, punched according to the shape of a corresponding unfolded drawing, through bending and coining, and plating. Accordingly, the second connecting leg (21), the second external contact part (22), the second cylindrical part (23), the second hook (24), the second stopper (25), and the second connecting part (26) are connected to each other.

[0050] The second connecting leg (21) is in the shape of a bar that extends roughly in a straight line (hence also called a ‘sliding bar’) and is in the shape of a straight (linear) strip, having the thickness of a metal plate, and is punched into a long rectangular shape. The second connecting leg (21) is inserted into the cylindrical internal space of the coil spring (30) and slides relative to the first connecting leg (11) while in physical (hence electrical) contact, and the contact area (overlapping) with the first connecting leg (11) may vary depending on the compression and extension of the pogo pin.

[0051] Except for the area near the tip, the lateral width of the second connecting bridge (21) is mostly constant, at least within the section that can come into contact with the first axial section (31a) and the second axial section (32a).

[0052] The second external contact portion (22) is for electrical contact with the outside, such as a terminal (ball) of a semiconductor device or a pad of a PCB, and is formed on the opposite side (opposite end) of the second connecting leg (21) from the second plunger (20). The second external contact portion (22) is formed by a plurality (e.g., 6) of probes (22a) that extend from one end (outer end) of the second cylindrical portion (23) and are connected (formed) along the circumference on the outside of the second cylindrical portion (23).

[0053] The second cylindrical part (23) is formed by bending a metal plate into a cylindrical shape, with one end connected to the second connecting part (26) and the other end connected to a plurality of probes (second external contact part).

[0054] The second connecting part (26) connects the second connecting leg (21) and the second cylindrical part (23), and may be formed as a band that is bent at a 90-degree angle from the outer end of the second connecting leg (21) and then bent at a 90-degree angle in the opposite direction to connect the second connecting leg (21) and the second cylindrical part (23).

[0055] The second stopper (25) is a projection that protrudes laterally from the second connecting leg (21) near the outer end of the second connecting leg (21), and supports the other end (other end) of the coil spring (30) so that the coil spring (30) (end) does not slip outward.

[0056] The second hook (24) is a projection that protrudes laterally from the second connecting leg (21) slightly inside the second stopper (25), forming a small groove between it and the second stopper (25), allowing the other end of the coil spring (30) to be seated in this groove, and preventing the seated other end of the coil spring (30) from slipping inward.

[0057] The coil spring (30) is a compression spring wound in a coil shape, capable of repeatedly compressing and extending by a force applied to both ends, and its length in the longitudinal direction is variable. The coil spring (30) has multiple sections in which the inner diameters differ from each other (and accordingly, the outer diameters also differ from each other). As in the conventional free state, both ends of the coil spring (30) may have a reduced inner diameter.

[0058] In particular, the present invention has one or more axial sections having a reduced inner diameter at an intermediate position of the coil spring (30). Before the first connecting leg (11) and the second connecting leg (21) are inserted into the coil spring (30), the coil spring (30) has one or more axial sections having a reduced inner diameter at an intermediate position in the longitudinal direction. A single axial section may be composed of multiple turns in the coil spring, but is preferably formed with two or fewer turns, and more preferably with about one turn (one full rotation of the winding).

[0059] FIG. 5 is a cross-sectional view showing the axial section of a pogo pin according to the first embodiment of the present invention, FIG. 5(a) is a virtual representation for comparing the sizes of the connecting legs before they are inserted into the coil spring, and FIG. 5(b) is a drawing showing the state after the connecting legs are actually inserted into the coil spring.

[0060] Before the first connecting leg (11) and the second connecting leg (21) are inserted into the coil spring (30), the inner diameter (D1) of the axial section (31a, 32a) is smaller than the outer diameter (D2) (the diameter of the circle when the corresponding part is covered by a circle) of the part where the first connecting leg (11) and the second connecting leg (21) come into contact at the location where the axial section comes into contact. The inner diameter of the first axial section (31a) and the second axial section (32a) is smaller than the outer diameter of the part where the first connecting leg (11) and the second connecting leg (21) come into contact at the location where the axial sections come into contact.

[0061] Accordingly, according to the present invention, after the first connecting leg (11) and the second connecting leg (21) are inserted into the coil spring (30), the axial sections (31a, 32a) of the coil spring (30) tighten the first connecting leg (11) and the second connecting leg (21), thereby ensuring a tight seal between the first connecting leg (11) and the second connecting leg (21).

[0062] A widening section (hereinafter referred to as the "first widening section") is formed between the first axial section (31a) and one end of the coil spring, a widening section (hereinafter referred to as the "second widening section") is formed between the second axial section (32a) and the other end of the coil spring, and a widening section (hereinafter referred to as the "third widening section") is also formed between the first axial section (31a) and the second axial section (32a).

[0063] The inner diameter of each expansion section is formed to be larger than the inner diameter of the contraction section, and is formed to be slightly larger than the outer diameter when the first connecting leg and the second connecting leg are overlapped, and each expansion section is preferably formed with multiple turns.

[0064] When the pogo pin is in operation, each of the first shaft section (31a) and the second shaft section (32a) tightens the overlapping portion of the first connecting leg (11) and the second connecting leg (21).

[0065] When the first connecting leg (11) and the second connecting leg (21) are inserted into the axial section (31a, 32a) of the coil spring (30), the axial section is deformed or expanded. As shown in FIG. 5(b), when the first connecting leg and the second connecting leg are inserted into the axial section, the axial section is compressed from a circular shape into an elliptical shape. This deformation occurs because, when the first connecting leg (11) and the second connecting leg (21) overlap, the ratio of width to height in the cross-section is not usually 1:1. Therefore, the force exerted by the axial section on the connecting legs is cushioned with a certain degree of elasticity as the circular shape is deformed into an elliptical shape. As the axial section is deformed from a circular shape into an elliptical shape, it provides additional space for the connecting legs.

[0066] In addition, when the axial section is expanded by the connecting legs, it is distributed to the immediately adjacent upper and lower turns, thereby taking the insufficient length from the upper and lower turns. The force applied to the pair of connecting legs and tightening them is limited to a small force that slightly spreads or deforms (or spreads and deforms) the coil spring of approximately 1 turn, which is the axial section. This has the effect of tightening the pair of connecting legs with a force that prevents jamming while keeping the axial section relatively constant, thereby allowing the two connecting legs to maintain stable contact.

[0067] In the coil spring (30), a first axial diameter section (31a), which is one of the axial diameter sections, and a second axial diameter section (32a), which is another axial diameter section, are each formed, and a third expansion section is placed between the first axial diameter section (31a) and the second axial diameter section (32a), and they are formed spaced apart from each other. There are multiple turns between the first axial diameter section (31a) and the second axial diameter section (32a).

[0068] Since the first axis section (31a) and the second axis section (32a), which are spaced apart from each other, tighten the pair of connecting legs at two different points of the pair of connecting legs, it has the effect of making it easier for the two connecting legs to maintain contact over a wider area.

[0069] As shown in FIG. 4(b), in the working state, the connecting leg pair is tightened at two separated points among the overlapping parts, thereby preventing the contact area from becoming smaller or the contact from becoming linear due to misalignment of the connecting leg pair. When the pogo pin is stored in the cylindrical space of the socket and then pressurized by the semiconductor element, the plunger often receives a force that causes it to fall sideways, deviating from its position of standing upright in the exact vertical direction. In such cases, the contact area of ​​the connecting leg pair can be drastically reduced, but the present invention has the effect of allowing a wider contact area even in such cases.

[0071] FIG. 6 is a cross-sectional view showing the axial section of a pogo pin according to a first variant of the present invention, where FIG. 6(a) is a hypothetical representation showing the size comparison of the connecting legs before inserting them into the coil spring, and FIG. 6(b) is after actually inserting the connecting legs into the coil spring.

[0072] In each plunger, the cylindrical part, hook, stopper, and external contact part are configured symmetrically with respect to the central axis of the pogo pin, but the connecting leg is configured eccentrically. The first connecting leg (11) is eccentrically oriented in one direction from the vertical axis of the coil spring (30), and the second connecting leg (21) is eccentrically oriented in the opposite direction from the vertical axis of the coil spring (30).

[0073] Looking at the first connecting leg (11), in the width direction (W), one side is pressed by contacting the coil spring, but the other side is spaced apart from the coil spring to form an escape space (S1). Looking at the second connecting leg (21), in the width direction (W), the other side is pressed by contacting the coil spring, but one side is spaced apart from the coil spring to form an escape space (S2). By cutting out the space corresponding to the escape space from the connecting legs shown in FIGS. 1 to 5, such an escape space can be formed.

[0074] These escape spaces (S1, S2) help to insert the pair of connecting legs more smoothly and to allow the connecting legs to operate more smoothly when inserted into the shaft portion (31a, 32a), and the shaft portion may be made to become a smaller, deformed elliptical shape instead of a circular shape.

[0076] Referring to FIGS. 7 and FIGS. 8 below, the external contact portion of the pogo pin according to the first embodiment of the present invention will be examined in detail.

[0077] The external contact portion (12, 22) is configured to include a plurality of probes (12a, 22a), and each probe can be elastically bent after contacting an external contact surface at a different point. For example, the external contact surface may be a terminal (ball, pad) of a semiconductor device or a pad of a PCB, etc.

[0078] Each probe is connected at one end to a cylindrical part (circumference of the cylindrical part) and is curved so as to converge toward the central axis of the cylindrical part as it approaches the free end. Each probe extends outward toward the pogo pin, but at the same time extends obliquely in a direction that converges toward the central axis of the cylindrical part, and its width narrows toward the free end.

[0079] As shown in FIG. 3 and FIG. 7(a), in the free state, the free ends of the probes are not in contact with each other and have a slight gap between them. Then, as shown in the working state of FIG. 7(b) and the max state of FIG. 7(c), when the pogo pin is pressed from the outside, the probes can tilt further down, and the free ends can come together while narrowing the gap between them.

[0080] The free end of each probe starts contacting the external contact surface at a contact angle (A) of 45 degrees or less, and then the contact angle can gradually decrease as pressure is applied.

[0081] The height of each probe (vertical direction, i.e., lengthwise height) decreases as the applied pressure increases. In the working state, the height decreases by D3 compared to the free state, and in the max state, the height decreases by D4 compared to the free state.

[0082] The cylindrical crown disclosed in prior art documents such as Patent Document 1 has a problem in that only some or one horn makes contact when there are minute differences due to processing reasons. However, according to the external contact part of the present invention, even if there are minute differences (height differences) due to processing reasons, the height difference is overcome during the process of pressing the probe, thereby enabling more probes or the entire probe to make contact with the outside. Accordingly, contact with the outside is made stable, and in particular, in high voltage and high current applications, the problem of sparks occurring or burning out is eliminated or reduced, resulting in a safer effect.

[0084] Hereinafter, a pogo pin according to a second embodiment of the present invention will be described in detail with reference to FIGS. 9 to 13.

[0085] The pogo pin (2) according to the second embodiment of the present invention comprises a first plunger (60), a second plunger (70), and a coil spring (80). The pogo pin (2) according to the second embodiment of the present invention includes many parts that are identical or similar to the pogo pin (1) according to the first embodiment of the present invention, and descriptions related to the identical or similar parts may be largely omitted.

[0086] The pogo pin (2) has the first connecting leg (61) of the first plunger (60) inserted through one side of the coil spring (30) and the second connecting leg (71) of the second plunger (70) inserted through the other side of the coil spring (80), and can slide with the first connecting leg (61) and the second connecting leg (71) in contact with each other.

[0087] The first plunger (60) is configured to include a first connecting leg (61), a first external contact part (62), a first cylindrical part (63), a first stopper (65), and a first connecting part (66). The first plunger (60) can be manufactured by processing a single metal plate, punched according to the shape of a corresponding unfolded drawing, through bending and coining, and plating. In the first plunger (60), a hook adjacent to the first stopper is not configured.

[0088] The first connecting leg (61) is equipped with a first connecting leg body (61a) and a first projection (61b). The first connecting leg body (61a) is in the shape of a bar that extends in a straight line (hence also called a 'sliding bar') and is in the shape of a straight strip. The first projection (61b) is formed at an intermediate position of the first connecting leg (61), and its outer diameter is expanded at an intermediate position in the longitudinal direction, and it protrudes laterally with the same thickness as the connected first connecting leg body (61a). Therefore, when punching a metal plate, it can be punched in a shape that has a straight strip with additional projections on the unfolded pattern.

[0089] The transverse width of the first connecting leg (61) is mostly constant, but is slightly extended transversely at the portion of the first projection (61b). The first external contact portion (62), the first cylindrical portion (63), and the first stopper (65) are substantially identical to the first external contact portion (12), the first cylindrical portion (13), and the first stopper (65) of the first embodiment, respectively. The first plunger (60) is provided with a first stopper (65) that supports one end of the coil spring (80), but there is no hook for hooking one end of the coil spring (80).

[0090] The second plunger (70) is configured to include a second connecting leg (71), a second external contact part (72), a second cylindrical part (73), a second stopper (75), and a second connecting part (76). The second plunger (70) can be manufactured by processing a single metal plate, punched according to the shape of the corresponding unfolded shape, through bending and coining, and plating. In the second plunger (70), a hook adjacent to the second stopper is not configured.

[0091] The second connecting leg (71) is equipped with a second connecting leg body (71a) and a second projection (71b). The second connecting leg body (71a) is in the shape of a bar extending in a straight line and is in the shape of a straight strip. The second projection (71b) is formed at an intermediate position of the second connecting leg (71), and its outer diameter is expanded at an intermediate position in the longitudinal direction, and it protrudes laterally with the same thickness as the connected second connecting leg body (71b). Therefore, when punching a metal plate, it is sufficient to punch it in a shape that has a straight strip with an additional projection on the unfolded pattern.

[0092] The lateral width of the second connecting leg (71) is mostly constant, but is slightly extended laterally at the portion of the second projection (71b). The second external contact portion (72), the second cylindrical portion (73), and the second stopper (75) are substantially identical to the second external contact portion (22), the second cylindrical portion (23), and the second stopper (25) of the first embodiment, respectively.

[0093] The second plunger (70) is provided with a second stopper (75) that supports the other end of the coil spring (80), but there is no hook for hooking the other end of the coil spring (80).

[0094] The coil spring (80) has multiple sections in which the inner diameters differ from each other (and accordingly, the outer diameters also differ from each other). In particular, the present invention has one or more reduced diameter sections having a reduced inner diameter at an intermediate position of the coil spring (80). Before the first connecting leg (61) and the second connecting leg (71) are inserted into the coil spring (80), the coil spring (80) has one or more reduced diameter sections having a reduced inner diameter at an intermediate position in the longitudinal direction. A single reduced diameter section may be composed of multiple turns in the coil spring, but is preferably formed by two or fewer turns, and more preferably by about one turn (one full rotation of the winding).

[0095] Before the first connecting leg (61) and the second connecting leg (71) are inserted into the coil spring (80), the inner diameter of the axial section (81a, 82a) (see D5' in FIG. 12) is smaller than the outer diameter of the part where the first connecting leg (61) and the second connecting leg (71) come into contact with each other at the location where the axial section contacts (the diameter of the circle when the corresponding part is covered by a circle). FIG. 12 is a hypothetical cross-sectional view showing the size comparison of the connecting legs before they are inserted into the coil spring in a pogo pin according to the second embodiment of the present invention.

[0096] When the first connecting leg (61) (and the second connecting leg (71)) is inserted into the first axial section (81a), the first axial section is deformed or expanded, and when the second connecting leg (71) (and the first connecting leg (61)) is inserted into the second axial section (82a), the second axial section is deformed or expanded.

[0097] According to the present invention, after the first connecting leg (61) and the second connecting leg (71) are inserted into the coil spring (80), the axial sections (81a, 82a) of the coil spring (80) tighten the first connecting leg (61) and the second connecting leg (71), and at least in the working state and the max state, the inner diameter (see D5 in FIG. 11) becomes equal to the outer diameter of the first connecting leg (61) and the second connecting leg (71). The axial sections (81a, 82a) of the coil spring (80) reliably ensure close contact between the first connecting leg (61) and the second connecting leg (71).

[0098] FIG. 13 is a schematic diagram that clearly explains the inner diameter (outer diameter) of a coil spring used in the second embodiment of the present invention. As shown in FIG. 13, the coil spring (80) includes a first expansion section (81b) located between one end of the coil spring and a first axial section (81a) and having an inner diameter larger than that of the first axial section (81a), a second expansion section (82b) located between the other end of the coil spring and a second axial section (82a) and having an inner diameter larger than that of the second axial section (82a), and a third expansion section (83b) located between the first axial section (81a) and the second axial section (82a) and having an inner diameter larger than that of the first axial section and the second axial section. When the pogo pin is actuated, the first expansion section, the second expansion section, and the third expansion section can all be compressed and expanded.

[0099] A first expansion section (81b) is formed between the first expansion section (81a) and one end (one side end) of the coil spring, a second expansion section (82b) is formed between the second expansion section (82a) and the other end (the other side end) of the coil spring, and a third expansion section (83b) is formed between the first expansion section (81a) and the second expansion section (82a). The inner diameter of each expansion section is formed to be larger than the inner diameter of the expansion section, and is formed to be slightly larger than the outer diameter when the first connecting leg and the second connecting leg are overlapped, and it is preferred that each expansion section be formed with multiple turns.

[0100] As shown in Fig. 12, it is preferred that the inner diameter of each expanded section be set so that there is a slight gap (D7) between the connecting bridge and the inner diameter.

[0101] The inner diameter of the first expansion section, the second expansion section, and the third expansion section is equal to or greater than the outer diameter (D6) of the first connecting leg in the part where the first projection (61b) is located, and equal to or greater than the outer diameter of the second connecting leg in the part where the second projection (71b) is located. When the pogo pin is operated, the first projection (61b) and the second projection (71b) can freely pass through the expansion section. However, when the pogo pin is operated, the first projection (61b) and the second projection (71b) cannot freely pass through the reduction section.

[0102] In the same manner as in the first embodiment, when the pogo pin is in operation, each of the first axial section (81a) and the second axial section (82a) tightens the overlapping portion of the first connecting leg (61) and the second connecting leg (71). When the first connecting leg (61) and the second connecting leg (71) are inserted into the axial sections (81a, 82a) of the coil spring (80), the axial section is deformed or expanded, becoming compressed from a circular shape into an elliptical shape.

[0103] The axial section has the effect of tightening the pair of connecting legs with a force that is relatively constant but does not cause a jam, thereby allowing the two connecting legs to maintain stable contact. Since the first axial section (81a) and the second axial section (82a), which are spaced apart from each other, tighten the pair of connecting legs at two different points of the pair of connecting legs, it has the effect of making it easier for the two connecting legs to maintain contact over a wider area.

[0104] The coil spring (80) is provided with a first axial section (81a) having a reduced inner diameter at an intermediate position in the longitudinal direction, wherein the outer diameter (D6) of the first connecting leg at the part where the first projection (61b) is located is larger than the inner diameter of the first axial section (81a). The first projection (61b) located inside the first axial section (81a) cannot slide over the first axial section (61a) and slip out due to the force caused by the self-weight of the first plunger (60).

[0105] When manufacturing the socket, the process involves moving the assembled pogo pin (2) as shown in FIG. 9 and mounting it onto the socket. During this manufacturing process, the first projection (61b) does not slide over the first shaft section (81a) and fall out, thereby preventing the first plunger from being separated from the assembled pogo pin (2).

[0106] And, the first projection (61b) is provided with a first slope (P1) facing inward and a second slope (P2) facing outward, wherein the first slope (P1) has a gentler slope than the second slope (P2), and conversely, the second slope (P2) has a much steeper slope than the first slope (P1), thereby preventing it from falling off due to its own weight. In addition, the gentle first slope (P1) of the first projection (61b) helps the first projection (61b) to ride over the first axis section (81a) by means of an external force when assembling the pogo pin (2).

[0107] The coil spring (80) is provided with a second axial section (82a) having a reduced inner diameter at an intermediate position in the longitudinal direction, wherein the outer diameter of the second connecting leg at the part where the second projection (71b) is located is larger than the inner diameter of the second axial section (82a). The second projection (71b) located inside the second axial section (82a) cannot slide over the second axial section (82a) and slip out due to the force caused by the self-weight of the second plunger (70).

[0108] When manufacturing the socket, the process involves moving the assembled pogo pin (2) as shown in FIG. 9 and mounting it onto the socket. During this manufacturing process, the second projection (71b) does not slide over the second shaft section (82a) and fall out, thereby preventing the second plunger from being separated from the assembled pogo pin (2).

[0109] And, the second projection (71b) is provided with a first slope facing inward and a second slope facing outward, wherein the first slope has a gentler slope than the second slope, and conversely, the second slope has a much steeper slope than the first slope, thereby preventing it from sliding due to its own weight. In addition, the gentle first slope of the second projection (71b) helps the second projection (71b) to slide over the second axis section (82a) by means of an external force when the pogo pin (2) is assembled.

[0110] In the above description, it was assumed that protrusions are formed on both the first and second connecting legs, but they may be formed on only one side. For example, they may be formed only on the first connecting leg that is on the lower side when viewed from the vertical direction, and the first connecting leg may always be on the lower side when handling the pogo pin after assembly.

[0112] FIG. 11 is a front view showing a coil spring in cross-section in a pogo pin according to a second embodiment of the present invention, FIG. 11(a) is in a free state, FIG. 11(b) is in a working state, and FIG. 11(c) is in a max state.

[0113] According to the prior art (the technology of Patent Document 1), there is a problem in that the inner diameter at both ends of the coil spring is reduced and the Max stroke of the pogo pin is reduced, but according to the present invention, the connecting leg is prevented from slipping outward by the protrusion located in the middle position of the connecting leg and the axial section of the coil spring. For example, in the working state and the Max state, the first protrusion (61a) rides up along the third enlarged section (83b) in the drawing, but in a state such as holding the top of the pogo pin with one's hand (similar to the free state drawing of FIG. 11(a)), the first protrusion (61a) is caught in the first axial section (81a) by its own weight and does not slip out.

[0114] According to the present invention, it is not necessary to configure a hook, and the enlarged portions (first enlarged portion and second enlarged portion) can be formed all the way to the end without the need to reduce the inner diameter at both ends of the coil spring, and the connecting leg on the opposite side can pass through the end of the coil spring (see F in FIG. 11(c)).

[0115] According to the present invention, the range in which the increase in stroke and the increase in spring force are proportional is greatly increased, and the effect of greatly increasing the Max stroke is achieved. According to the present invention, the range in which minute height differences between tens to thousands of terminals in a semiconductor device can be overcome is greatly increased, and the effect of preventing problems such as the terminals (balls) of the semiconductor device being crushed is achieved.

[0116] According to the present invention, the conventional hook can be eliminated by utilizing the axial section, which allows the two connecting legs to maintain stable contact by tightening a pair of connecting legs. Since the coil spring of the conventional hook part has almost no compression or extension, it does not contribute to the stroke; however, the axial section according to the present invention allows for compression and extension and contributes to the stroke, thereby having the effect of further extending the effective length of the coil spring. Explanation of the symbols

[0117] 10, 20, 50, 60: Plunger 11, 21, 61, 71: Connecting bridge 12, 22, 62, 72: External contact parts 13, 23, 63, 73: Cylindrical part 14, 24 : Hanger 15, 25, 65, 75: Stopper 16, 26, 66, 76 : connection part 30, 80: Coil spring 61a, 71a : Connecting bridge body 61b, 71b: protrusions

Claims

Claim 1 A pogo pin wherein a first connecting leg of a first plunger is inserted through one side of a coil spring and a second connecting leg of a second plunger is inserted through the other side of the coil spring, and the first connecting leg and the second connecting leg can slide while in contact with each other, wherein, before the first connecting leg and the second connecting leg are inserted into the coil spring, the coil spring has one or more axial diameter sections having a reduced inner diameter at an intermediate position in the longitudinal direction, and when the first connecting leg and the second connecting leg are inserted into the axial diameter sections, the axial diameter sections are deformed or expanded, and wherein the coil spring has a first axial diameter section, which is one of the axial diameter sections, and a second axial diameter section, which is another of the axial diameter sections, respectively formed therein, wherein the first axial diameter section and the second axial diameter section are formed spaced apart from each other. Claim 2 A pogo pin according to claim 1, wherein the inner diameter of the shaft section before the first connecting leg and the second connecting leg are inserted into the coil spring is smaller than the outer diameter of the portion where the first connecting leg and the second connecting leg come into contact with each other. Claim 3 A pogo pin according to claim 2, wherein the first connecting leg is eccentrically offset in one direction from the vertical axis of the coil spring, and the second connecting leg is eccentrically offset in the opposite direction from the vertical axis of the coil spring. Claim 4 A pogo pin according to claim 1, wherein when the first connecting leg and the second connecting leg are inserted into the axial section, the axial section is compressed from a circular shape into an elliptical shape. Claim 5 delete Claim 6 A pogo pin according to claim 1, wherein when the pogo pin is in operation, each of the first axial section and the second axial section tightens the portion where the first connecting leg and the second connecting leg overlap. Claim 7 A pogo pin according to claim 1, wherein an external contact portion for electrical contact with the outside is formed on the opposite side of the first connecting leg of the first plunger, the external contact portion is configured to include a plurality of probes, each of which can be elastically bent after contacting an external contact surface at different points. Claim 8 In claim 7, each of the probes is a pogo pin having one end connected to a cylindrical part and then curved so as to converge toward the central axis of the cylindrical part as it moves toward the free end. Claim 9 A pogo pin according to claim 8, wherein the free end starts contacting the outer contact surface at a contact angle of 45 degrees or less, and the contact angle gradually decreases as pressure is applied.

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