PROBE PEN AND ELECTRONIC DEVICE WITH IT

Description

TECHNICAL FIELD

[0001] The present invention relates to a probe pin, and more particularly to a probe pin for inspecting a ball grid array (BGA) type semiconductor IC in which a large number of ball solders are arranged on the bottom surface.BACKGROUND ART

[0002] As a probe pin for inspecting a BGA type semiconductor IC, there is a contact for an electronic device disclosed in Patent Document 1, for example.

[0003] That is, as illustrated in Figs. 26(A) to 26(C), there is a probe pin for inspecting the semiconductor IC 101 by coming into contact with a ball-like lead 102 provided on the bottom surface of the semiconductor IC 101. As illustrated in Figs. 27 and 28, a contact part 111, cut out into a substantially V shape, in an upper contact pin 110 comes into contact with the ball-like lead 102 for electrical connection, so that the probe pin can inspect the semiconductor IC 101.

[0004] Further prior art documents are US 2013 / 257467 A1, US 2013 / 002285 A1, JP 2012 181096 A, KR 2012 0104878 A, non-patent literature MASSON A: "LES POINTES DE TEST INFLUENCENT LE RESULTAT DES MESURES", MESURES REGULATION AUTOMATISME, CFE. PARIS, FR, no. 693, 1 March 1997 (1997-03-01), pages 73-76, XP000722338, ISSN: 0755-219X, JP 2007 139567 A, JP 2016 038207 A, WO 2011 / 071082 A1 and WO 2015 / 194384 A1.

[0005] US 2013 / 257467 A1 discloses the preambles of independent claims 1, 3 and 4.PRIOR ART DOCUMENTPATENT DOCUMENT

[0006] Patent Document 1: JP 2008-516398 ASUMMARY OF THE INVENTIONPROBLEMS TO BE SOLVED BY THE INVENTION

[0007] However, in the upper contact pin 110, the lead 102 merely comes into contact with the contact surface of the substantially V shaped contact part 111. As a result, an oxide film formed on the surface of the lead 102 cannot be reliably scraped off, causing contact failure to easily occur and variation in inspection accuracy to easily occur, which has been problematic.

[0008] In view of the above problem, it is an object of the present invention to provide a probe pin in which contact failure hardly occurs and has uniform inspection accuracy. This object is achieved by the subject matter of the independent claims. Further advantageous modifications and embodiments of the invention are the subject matter of the dependent claims. The invention is defined by the independent claims. Aspects of the invention are set out below.

[0009] A probe pin according to one aspect of the present invention as defined in one of claims 1, 3 and 4, is a probe pin including: an elastic part extending and contracting along a center line; a first contact disposed on one side of the center line and having a rectangular cross section; and a second contact disposed on the other side of the center line and having a rectangular cross section, the probe pin being where the first contact and the second contact are supported so as to be reciprocable via the elastic part and are electrically connected to each other, and it is configured such that a contact surface of at least one of the first contact and the second contact is an inclined surface inclined so as to descend along a thickness direction.EFFECT OF THE INVENTION

[0010] According to the above aspect of the present invention, when a ball solder comes into contact with the inclined contact surface of the contact, the ball solder slides on the contact surface, so that the oxide film of the ball solder is scraped off. Therefore, contact failure hardly occurs, and probe pins having no variation in inspection accuracy can be obtained.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Fig. 1 is a perspective view illustrating a probe pin according to a first comparative example not claimed. Fig. 2 is an exploded perspective view of the probe pin illustrated in Fig. 1. Figs. 3(A), 3(B) and 3(C) are a front view, a plan view, and a bottom view of the probe pin illustrated in Fig. 1. Figs. 4(A) and 4(B) are a partial enlarged right side view and a partial enlarged rear view of the probe pin illustrated in Fig. 1. Figs. 5(A) and 5(B) are a rear view and a plan view illustrating an inspection unit which is an example of an electronic device according to the present invention. Fig. 6 is a sectional view taken along a line VI-VI of the inspection unit illustrated in Fig. 5. Fig. 7 is a partial perspective view illustrating a probe pin according to a second comparative example not claimed. Figs. 8(A) and 8(B) are a partial enlarged left side view and a partial enlarged rear view of the probe pin illustrated in Fig. 7. Fig. 9 is a partial perspective view illustrating a probe pin according to a third comparative example not claimed. Figs. 10(A) and 10(B) are a partial enlarged left side view and partial enlarged rear view of the probe pin illustrated in Fig. 9. Fig. 11 is a partial perspective view illustrating a probe pin according to a first embodiment of the present invention. Figs. 12(A) and 12(B) are a partial enlarged left side view and a partial enlarged rear view of the probe pin illustrated in Fig. 11. Fig. 13 is a partial perspective view illustrating a probe pin according to a second embodiment of the present invention. Figs. 14(A) and 14(B) are a partial enlarged left side view and a partial enlarged rear view of the probe pin illustrated in Fig. 13. Fig. 15 is a partial perspective view illustrating a probe pin according to a fourth comparative example not claimed. Figs. 16(A) and 16(B) are a partial enlarged rear view and a partial enlarged left side view of the probe pin illustrated in Fig. 15. Fig. 17 is a partial perspective view illustrating a probe pin according to a third embodiment of the present invention. Figs. 18(A) and 18(B) are a partial enlarged rear view and a partial enlarged left side view of the probe pin illustrated in Fig. 17. Fig. 19 is a partial perspective view illustrating a probe pin according to an fourth embodiment of the present invention. Figs. 20(A) and 20(B) are a partial enlarged rear view and a partial enlarged left side view of the probe pin illustrated in Figs. 18(A) and 18(B). Fig. 21 is a partial perspective view illustrating a probe pin according to a fifth comparative example not claimed. Figs. 22(A) and 22(B) are a partial enlarged rear view and a partial enlarged left side view of the probe pin illustrated in Fig. 21. Fig. 23 is a partial perspective view illustrating a probe pin according to a sixth comparative example not claimed. Figs. 24(A) and 24(B) are partial enlarged rear view and partial enlarged left side view of the probe pin illustrated in Fig. 23. Fig. 25 is a partial perspective view illustrating a probe pin according to a modification of the first comparative example not claimed. Fig. 26A is a plan view of a semiconductor IC of Patent Document 1. Fig. 26B is a side view of the semiconductor IC of Patent Document 1. Fig. 26C is a rear view of the semiconductor IC of Patent Document 1. Fig. 27 is a perspective view of a probe pin of Patent Document 1. Fig. 28 is a front view of the probe pin of Patent Document 1. MODES FOR CARRYING OUT THE INVENTION

[0012] Before continuing with the description of the present invention, the same reference numerals are provided to the same parts in the accompanying drawings.

[0013] Hereinafter, a first comparative example not claimed will be described in detail with reference to the drawings.

[0014] A probe pin will be described with reference to the attached drawings of Figs. 1 to 24.

[0015] In the following description, in order to describe the configuration shown in the drawing, terms indicating directions such as "upper", "lower", "left", and "right", in addition to "X direction", "Y direction", and "Z direction", and other terms including those terms will be used. The purpose of using these terms is to facilitate understanding of the embodiments and comparative examples through the drawings. Accordingly, those terms do not necessarily indicate directions used at the time of actually using the embodiments of the present invention. A technical scope of the invention recited in the claims shall not be restrictively interpreted by using those terms.

[0016] As illustrated in Figs. 1 to 6, the probe pin 10 according to the first comparative example not claimed includes a coil spring 11 as an example of an elastic part, a first plunger 20, and a second plunger 30. Each of the first and second plungers 20, 30 has electrical conductivity, and is formed by, for example, an electroforming method. The coil spring 11 expands and contracts along a center line. A first contact 25 is disposed on one side on the center line and has a rectangular cross section. A second contact 34 is disposed on the other side on the center line and has a rectangular cross section. The first contact 25 and the second contact 34 are supported so as to be reciprocable via the coil spring 11 and are electrically connected to each other as a probe pin 10.

[0017] The coil spring 11 is formed of carbon steel or stainless steel, for example. As illustrated in Figs. 2 and 3(A) to 3(C), an inner diameter of the coil spring 11 is slightly larger than the width dimension (X1-X2 direction) of a clamped part 21 of the first plunger 20, which will be described later. The inner diameter of the coil spring 11 is slightly larger than the width dimension (Y1-Y2 direction) of each of the first and second elastic pieces 32, 33 provided on the second plunger 30, which will be described later. Further, an outer diameter of the coil spring 11 is mostly the same as the width dimension (X1-X2 direction) of each of the retaining parts 24, 24 of the first plunger 20. The outer diameter of the coil spring 11 is mostly the same as the width dimension (Y1-Y2 direction) of each of the retaining parts 35, 35 of the second plunger 30.

[0018] Note that the length dimension (Z1-Z2 direction) of the coil spring 11 may be adjusted such that the coil spring 11 is constantly compressed as required in the state illustrated in Figs. 5, 6(A) and 6(B), or may be adjusted such that the coil spring 11 comes into a free state without compression.

[0019] As illustrated in Figs. 2 and 3(A) to 3(C), the first plunger 20 has a flat plate shape extending along the Z1-Z2 direction and is formed to have mostly the same thickness dimension. The first plunger 20 is made up of the clamped part 21 and a first contact part 22 continuous from the clamped part 21 in the Z1 direction. In the first plunger 20, the surface along the X1-X2 direction is a main surface, and the surface along the Y1-Y2 direction orthogonal to the main surface is a side surface.

[0020] The clamped part 21 has a rectangular guide groove 23 penetrating the main surface. The guide groove 23 is formed along the Z1 direction from the lower end edge of the clamped part 21. The width dimension (X1-X2 direction) of the guide groove 23 is larger than a thickness dimension (X1-X2 direction) of the second plunger 30.

[0021] The first contact part 22 has the first contact 25 at its tip (the upper end in Fig. 2). The first contact 25 has a substantially V shape as seen from the main surface. Further, as illustrated in Fig. 4(A), a contact surface of the first contact 25 is constituted by an inclined surface which is inclined so as to descend in the Y2 direction to form a wiping surface. An inclination angle is preferably 1 degree to 10 degrees, particularly preferably 2 degrees to 3 degrees. This is because, when the inclination angle is less than 1 degree, an oxide film of the ball solder cannot be efficiently scraped off, and when the inclination angle exceeds 10 degrees, the manufacturing by the electroforming method becomes difficult. Further, from both side surfaces located at the base end (the lower end in Fig. 2) of the first contact part 22, the retaining parts 24, 24 respectively extend in the X1-X2 direction. As illustrated in Fig. 6, the width dimension of each of the retaining parts 24, 24 in the X1-X2 direction is smaller than an inner diameter of a first housing hole 46 of a housing cover 45, described later, and is larger than an inner diameter of a first sliding hole 47. It is sufficient that the contact surface of at least one of the first contact 25 and the second contact 34 is inclined so as to descend along the thickness direction. Although the first contact 25 is described here, the contact surface of the second contact 34 may be made inclined so as to descend along the thickness direction.

[0022] As illustrated in Fig. 2, the second plunger 30 has a flat plate shape extending along the Z1-Z2 direction and is formed to have mostly the same thickness dimension. The second plunger 30 is made up of a second contact part 31 and the first and second elastic pieces 32, 33 extending from the base end (the upper end in Fig. 2) of the second contact part 31 in the Z1 direction. A surface along the Y1-Y2 direction of the second plunger 30 is defined as a main surface, and a surface along the X1-X2 direction orthogonal to the main surface is defined as a side surface.

[0023] The second contact part 31 has a flat plate shape having a substantially rectangular cross section, and the second contact 34 having a V shape as seen from the main surface is provided at the tip (the lower end in Fig. 2) of the second contact part 31. Further, from both side surfaces located at the base end (the upper end in Fig. 2) of the second contact part 31, the retaining parts 35, 35 respectively protrude in the Y1-Y2 direction. As illustrated in Fig. 6, similarly to the retaining parts 24, 24 described above, the width dimension of each of the retaining parts 35, 35 in the Y1-Y2 direction is smaller than an inner diameter of a second housing hole 42 of a housing body 41 described later, and is larger than an inner diameter of a second sliding hole 43.

[0024] The first and second elastic pieces 32, 33 extend from the base end of the second contact part 31 in parallel at a predetermined interval therebetween and along the Z1 direction. Further, the first and second elastic pieces 32, 33 extend from both side edges of the base end of the second contact part 31 so as to have a gap larger than the thickness dimension (Y1-Y2 direction) of the first plunger 20.

[0025] The distance between the outer surfaces of the first and second elastic pieces 32, 33, namely, the distance in the Y1-Y2 direction is substantially equal to the width dimension of the second contact part 31 in the Y1-Y2 direction. The distance between the opposed inner surfaces of the first and second elastic pieces 32, 33 is larger than the thickness dimension (Y1-Y2 direction) of the first plunger 20. The first elastic piece 32 is longer than the second elastic piece 33.

[0026] Moreover, a contact protrusion 36 protrudes toward the Y2 direction at the tip of the inner surface of the first elastic piece 32. A guide protrusion 37 protrudes toward the Y1 direction at the tip of the inner surface of the second elastic piece 33. The probe pin is formed such that, when the guide protrusion 37 of the second elastic piece 33 is fitted into the guide groove 23 of the first plunger 20, the contact protrusion 36 always comes into contact with the main surface of the clamped part 21 of the first plunger 20.

[0027] Next, a process of assembling an inspection unit 40 provided with the probe pin 10 of the first comparative example not claimed will be described. The inspection unit 40 is an example of an electronic device.

[0028] First, the probe pin 10 is assembled. First, as illustrated in Fig. 2, the clamped part 21 of the first plunger 20 is inserted from the upper end side of the coil spring 11 in the Z1 direction. Then, the first and second elastic pieces 32, 33 of the second plunger 30 are inserted from the lower end side of the coil spring 11 in the Z2 direction. At this time, as illustrated in Figs. 3(A), the first and second plungers 20, 30 are assembled such that the main surface of the first plunger 20 and the main surface of the second plunger 30 are orthogonal to each other.

[0029] When the first and second plungers 20, 30 are inserted deeply into the coil spring 11, the clamped part 21 of the first plunger 20 is inserted between the first and second elastic pieces 32, 33 of the second plunger 30. Hence, the clamped part 21 is sandwiched between the first elastic piece 32 and the second elastic piece 33. Further, when the first and second plungers 20, 30 are inserted deeply into the coil spring 11, the guide protrusion 37 of the second plunger 30 is fitted into the guide groove 23 of the first plunger 20, to connect the first and second plungers 20, 30. As a result, the assembly of the probe pin 10 having the configuration in which the first and second plungers 20, 30 are coupled to each other so as to be slidable in the coil spring 11 is completed. At this time, the contact protrusion 36 of the second elastic piece 33 of the second plunger 30 is constantly in contact with the main surface located above the guide groove 23, illustrated in Fig. 2, out of the main surface of the clamped part 21 of the first plunger 20.

[0030] Next, as illustrated in Figs. 5, 6(A) and 6(B), the assembled probe pin 10 is assembled into the insulative housing of the inspection unit 40. That is, the second plunger 30 is inserted into the second housing hole 42 provided in the insulating housing body 41 constituting the housing. Then, after the second contact part 31 and the first and second elastic pieces 32, 33 of the second plunger 30 are respectively housed into the second sliding hole 43 and the second housing hole 42 of the housing body 41, the housing body 41 is covered with an insulating housing cover 45. As a result, the clamped part 21 and the first contact part 22 of the first plunger 20 are respectively housed into the first housing hole 46 and the first sliding hole 47 of the housing cover 45, and the assembling work of the inspection unit 40 is completed.

[0031] As illustrated in Fig. 6, in the inspection unit 40, the assembling work of which has completed, the retaining part 24 of the first plunger 20 is engaged with the inner opening edge of the first sliding hole 47 of the housing cover 45. Similarly, the retaining part 35 of the second plunger 30 is engaged with the inner opening edge of the second sliding hole 43 of the housing body 41. Then, the coil spring 11 is compressed by the retaining part 24 and the retaining part 35. Further, the first contact part 22 of the first plunger 20 protrudes from the first sliding hole 47 of the housing cover 45. Similarly, the second contact part 31 of the second plunger 30 protrudes from the second sliding hole 43 of the housing body 41.

[0032] When the inspection unit 40 having a large number of probe pins 10 is to be assembled, the same assembling work as described above may be repeated.

[0033] Next, the operation of the probe pin 10 assembled in the inspection unit 40 will be described.

[0034] First, the second contact part 31 of the inspection unit 40 is positioned above a printed wiring board 50, and the inspection unit 40 is lowered. Thereby, the second contact 34 of the second contact part 31 is pressed against a connection pad 51 of the printed wiring board 50. Hence, the coil spring 11 is further compressed through the retaining part 35 of the second plunger 30.

[0035] Then, an inspection object 60 is positioned above the inspection unit 40, and the inspection object 60 is lowered. Thereby, a ball solder 61 of the inspection object 60 is pressed against the first contact 25, having the V shaped cross section, of the first plunger 20. Hence, the retaining part 24 of the first plunger 20 pushes down and compresses the coil spring 11. As a result, the clamped part 21 of the first plunger 20 descends and the guide protrusion 37 of the second plunger 30 slides in the guide groove 23 of the first plunger 20. At the same time, the contact protrusion 36 of the second plunger 30 slides on the main surface of the clamped part 21 of the first plunger and is electrically connected. It is thereby possible to inspect whether or not the inspection object 60 normally operates.

[0036] According to the comparative example, as illustrated in Figs. 4(A) and 4(B), the contact surface of the first contact 25 is inclined so as to descend in the Y2 direction. Therefore, the ball solder 61 slides along the wiping surface which is the contact surface descending in the Y2 direction, and the oxide film of the ball solder 61 is scraped off on the contact surface of the first contact 25. As a result, contact failure does not occur and variation in inspection accuracy does not occur.

[0037] Particularly, when the ball solder 61 comes into partial contact with the first contact 25, the ball solder 61 is also scraped along the V shaped inclined surface of the first contact 25. Thus, since the oxide film of the ball solder 61 is more reliably scraped off, contact failure is less likely to occur and the inspection accuracy is improved.

[0038] Further, since the contact surface of the first contact 25 has a V shape, there is an advantage that the ball solder 61 hardly falls off when the ball solder 61 comes into contact with the contact surface of the first contact 25.

[0039] Finally, when the inspection object 60 is pulled up and the ball solder 61 is released from the first contact 25, the retaining part 24 of the first plunger 20 is pushed up by the spring force of the coil spring 11. Then, the retaining part 24 of the first plunger 20 is engaged with the inner edge of the first sliding hole 47 of the housing cover 45, and returns to the initial state. Thereafter, repeating a similar operation enables inspection of the inspection object 60.

[0040] When the guide protrusion 37 of the second plunger 30 is fitted in the guide groove 23 of the first plunger 20, the contact protrusion 36 of the second elastic piece 32 is constantly pressed against the main surface of the clamped part 21 of the first plunger 20. Hence, it is possible to ensure high contact stability between the first and second plungers 20, 30.

[0041] The relative sliding movement of the first and second plungers 20, 30 is performed by the guide protrusion 37 of the second plunger 30 being engaged with the guide groove 23 of the first plunger 20. There is thus no variation in the contact position between the clamped part 21 of the first plunger 20 and the contact protrusion 36 of the second plunger 30, and an inspection unit having no variation in inspection accuracy can be obtained.

[0042] In the first comparative example not claimed, as illustrated in Fig. 25, as another example of the elastic part, the elastic part may be made up of a bellows-shaped elastic body 11G in place of the coil spring 11, and may have a form in which a first contact part 22G provided with the first contact 25 and a second contact part 31G provided with the second contact 34 are integrally molded so as to be mutually reciprocable via the elastic body 11G. With such a configuration, the structure can be simplified.

[0043] As illustrated in Figs. 7, 8(A) and 8(B), a probe pin according to a second comparative example not claimed is mostly the same as the above first comparative example not claimed, and the difference from the first comparative example not claimed is that a peeling projection 26 having a triangular cross section is provided in the center of the V shaped first contact 25 along the thickness direction. Since the others are similar to those in the above first comparative example not claimed, the same portions are provided with the same numerals, and descriptions thereof are omitted.

[0044] According to the comparative example, since the peeling projection 26 can more reliably peel off the oxide film of the ball solder, there is an advantage that the inspection accuracy is improved.

[0045] As illustrated in Figs. 9, 10(A) and 10(B), a probe pin according to a third comparative example not claimed is mostly the same as the above first comparative example not claimed except that the contact surface of the first contact 25 is inclined so as to descend in the X2 direction and is made a flat surface. Furthermore, the contact surface of the first contact 25 is inclined so as to also descend in the Y2 direction.

[0046] According to the comparative example, when the ball solder comes into contact with the contact surface of the first contact 25, the ball solder slides along the diagonal line of the contact surface of the first contact 25 and is scraped. Therefore, even when the cross-sectional area of the contact surface of the first contact part 22 is small, the ball solder slides a long distance. As a result, the oxide film of the ball solder can be reliably scraped off, and there is thus an advantage that it is possible to obtain a probe pin in which contact failure hardly occurs.

[0047] As illustrated in Figs. 11, 12(A) and 12(B), a probe pin according to a first embodiment is mostly the same as the above third comparative example not claimed except that an engagement projection 27 is provided on the X2 side edge of the contact surface of the first contact 25. As in the third comparative example not claimed, the contact surface of the first contact 25 is inclined so as to descend in the Y2 direction as well.

[0048] According to the embodiment, when a ball solder (not shown) comes into contact with the contact surface of the first contact 25, the oxide film of the ball solder is scraped along the contact surface of the first contact 25 and an oxide film is peeled off. It is thus possible to obtain a probe pin in which contact failure hardly occurs. In addition, since the ball solder is engaged with the engagement projection 27, there is an advantage that the ball solder hardly falls off.

[0049] As illustrated in Figs. 13, 14(A) and 14(B), a probe pin according to a second embodiment is mostly the same as the above first embodiment except that the peeling projection 26 having a triangular cross section is provided at the base part of the engagement projection 27 of the first contact 25 in the thickness direction. In addition, the contact surface of the first contact 25 is inclined so as to descend in the Y2 direction.

[0050] According to the embodiment, there is an advantage that the oxide film of the ball solder is more reliably scraped off by the peeling projection 26, and contact failure hardly occurs.

[0051] As illustrated in Figs. 15, 16(A) and 16(B), a probe pin according to a fourth comparative example not claimed is mostly the same as the above first comparative example not claimed except that the first contact 25 has a flat contact surface along the X1 direction and the X2 direction. Further, as illustrated in Fig. 16(B), the contact surface of the first contact 25 is inclined so as to descend in the Y2 direction.

[0052] According to the comparative example, since the shape of the first contact 25 is simple, there is an advantage that the probe pin 10 with the first plunger 20 easy to manufacture can be obtained.

[0053] As illustrated in Figs. 17, 18(A) and 18(B), a probe pin according to a third embodiment is mostly the same as the above fourth comparative example not claimed except that the engagement projection 27 having a triangular cross section is provided at the edge in the X2 direction side of the contact surface of the first contact 25 in the thickness direction (Y1-Y2 direction). As in the fourth comparative example not claimed, the contact surface of the first contact 25 is inclined so as to descend in the Y2 direction, as illustrated in Fig. 18(B).

[0054] According to the embodiment, the ball solder slides on the contact surface of the first contact 25 which is inclined so as to descend in the Y2 direction, and the oxide film of the ball solder is scraped off. Hence, a probe pin free from contact failure can be obtained. Further, since the ball solder is engaged with the engagement projection 27, there is an advantage that the ball solder hardly falls off.

[0055] As illustrated in Figs. 19, 20(A) and 20(B), a probe pin according to a fourth embodiment is mostly the same as the above fourth comparative example not claimed except that peeling grooves 28, 28 are provided at both side edges of the contact surface of the first contact 25 in parallel along the Y2 direction. As in the fourth comparative example not claimed, the contact surface of the first contact 25 is inclined so as to descend in the Y2 direction, as illustrated in Fig. 20(B).

[0056] According to the embodiment, the oxide film of the ball solder is scraped off by the peeling grooves 28, 28 provided along the Y1-Y2 direction. Hence, a probe pin free from contact failure can be obtained. In addition, since the ball solder is likely to be caught in the peeling groove 28, the ball solder hardly falls off.

[0057] As illustrated in Figs. 21, 22(A) and 22(B), a probe pin according to a fifth comparative example not claimed is mostly the same as the above fourth comparative example not claimed except that a recess 29 is formed at the corner in the X2 direction and the Y2 direction of the contact surface of the first contact 25. As in the fourth comparative example not claimed, the contact surface of the first contact 25 is inclined so as to descend in the Y2 direction, as illustrated in Fig. 22(B).

[0058] According to the comparative example, since the oxide film of the ball solder is scraped off in the recess 29 of the first contact 25, a probe pin free from contact failure can be obtained. The contact reliability is improved. In addition, since the ball solder is likely to be caught in the peeling groove 28, the ball solder hardly falls off.

[0059] As illustrated in Figs. 23, 24(A) and 24(B), a probe pin according to a sixth comparative example not claimed is mostly the same as the above fourth comparative example not claimed except that the contact surface of the first contact 25 is an arcuate surface. Further, as illustrated in Fig. 24(B), the first contact 25 is inclined so as to descend in the Y2 direction.

[0060] According to the comparative example, the ball solder slides on the contact surface of the first contact 25 and the oxide film of the ball solder is scraped off, so that a probe pin free from contact failure can be obtained. In particular, since the contact surface of the first contact 25 has an arcuate surface, the contact area is large and contact reliability is further improved. In addition, since the first contact 25 is an arcuate surface, there is an advantage that a probe pin with which the ball solder hardly falls off can be obtained.

[0061] According to the various aspects of the present invention, when the ball solder comes into contact with the inclined contact surface of the probe pin, the ball solder is scraped at the contact surface and the oxide film of the ball solder is scraped off. Therefore, contact failure is less likely to occur, and there is an effect that an electronic device with uniform inspection accuracy can be obtained.

[0062] Note that by appropriately combining freely selected embodiments or modifications of the above variety of embodiments and modifications, it is possible to achieve the respective effects of those combined. While it is possible to combine embodiments, combine examples, or combine an embodiment and an example, it is also possible to combine features in different embodiments or examples.

[0063] While the present invention has been fully described in connection with the preferred embodiments with reference to the accompanying drawings, a variety of modifications or corrections will be apparent to those skilled in the art. Such modifications or corrections are to be understood as being included in the scope of the invention according to the appended claims so long as not deviating therefrom.INDUSTRIAL APPLICABILITY

[0064] It is a matter of course that the probe pin according to the above aspect of the present invention is not limited to the above-described inspection unit, but may be applied to other electronic devices.DESCRIPTION OF SYMBOLS

[0065] 10probe pin 11coil spring (example of elastic part) 20first plunger 21clamped part 22first contact part 23guide groove 24retaining part 25first contact 26peeling projection 27engagement projection 28peeling groove 29recess 30second plunger 31second contact part 32first elastic piece 33second elastic piece 34second contact 35retaining part 36contact protrusion 37guide protrusion 40inspection unit 41housing body 42second storage hole 43second sliding hole 45housing cover 46first storage hole 47first sliding hole 50printed wiring board 51connection pad 60inspection object 61ball solder

Claims

1. A probe pin (10), comprising: an elastic part (11) extending and contracting along a center line in an extending direction; a first plate shaped plunger (20); a second plate shaped plunger (30); the first plunger (20) comprising a first contact (25) disposed on one side of the probe pin (10) in the direction of the center line and having a rectangular cross section; and the second plunger (30) comprising a second contact (34) disposed on another side of the probe pin (10) in the direction of the center line and having a rectangular cross section, wherein the first contact (25) and the second contact (34) are supported so as to be reciprocable via the elastic part (11) and are electrically connected to each other, the first contact (25) is an inclined surface which is disposed in an end face of the first contact (25) in the extending direction and inclined along the thickness direction of the first plunger (20), characterized in that the first contact (25) has an asymmetrical V shape with respect to a center of the first contact (25) in the width direction of the first plunger (20), and an engagement projection (27) is provided at one of end portions of the first contact (25) in the width direction of the first plunger (20), the one of the end portions having a tip that is closer to the second contact (34) in the extending direction than a tip of the other of the end portions, which engagement projection (27) can engage in the width direction of the first plunger (20) an inspection object (60) contacted by the first contact (25).

2. The probe pin according to claim 1, wherein the first contact (25) includes a peeling projection (26) that is positioned nearer to the center of the first contact (25) in the width direction than the engagement projection (27).

3. A probe pin (10), comprising: an elastic part (11) extending and contracting along a center line in an extending direction; a first plate shaped plunger (20); a second plate shaped plunger (30); the first plunger (20) comprising a first contact (25) disposed on one side of the probe pin (10) in the direction of the center line and having a rectangular cross section; and the second plunger (30) comprising a second contact (34) disposed on another side of the probe pin (10) in the direction of the center line and having a rectangular cross section, wherein the first contact (25) and the second contact (34) are supported so as to be reciprocable via the elastic part (11) and are electrically connected to each other, the first contact (25) is an inclined surface which is disposed in an end face of the first contact (25) in the extending direction and inclined along the thickness direction of the first plunger (20), characterized in that the first contact (25) includes a flat section extending along the width direction of the first plunger (20) and an engagement projection (27) having a triangular cross section, which can engage an inspection object (60) in the width direction of the first plunger (20) contacted by the first contact (25), disposed at an end of the flat section in the width direction of the first plunger (20).

4. A probe pin (10), comprising: an elastic part (11) extending and contracting along a center line in an extending direction; a first plate shaped plunger (20); a second plate shaped plunger (30); the first plunger (20) comprising a first contact (25) disposed on one side of the probe pin (10) in the direction of the center line and having a rectangular cross section; and the second plunger (30) comprising a second contact (34) disposed on another side of the probe pin (10) in the direction of the center line and having a rectangular cross section, wherein the first contact (25) and the second contact (34) are supported so as to be reciprocable via the elastic part and are electrically connected to each other, the first contact (25) is an inclined surface which is disposed in an end face of the first contact (25) in the extending direction and inclined along the thickness direction of the first plunger (20), the first contact (25) includes a peeling groove (28) extending along the thickness direction of the first plunger (20), characterized in that the peeling groove (28) is respectively formed only at both ends of a contact surface in the width direction of the first plunger (20), the contact surface being provided at an end face of the first contact (25) disposed at an extremity of the first contact (25) in the extending direction.

5. The probe pin according to any one of claims 1 to 4, comprising: a coil spring (11) being the elastic part; the first plunger (20) including a first contact part provided with the first contact (25); and the second plunger (30) including a second contact part provided with the second contact (34) wherein, the first and second plungers (20, 30) inserted respectively from both ends of the coil spring (11) are coupled to each other so as to be slidable in the coil spring (11).

6. The probe pin according to claim 5, wherein the first and second plungers (20, 30) are electroformed products.

7. The probe pin according to any one of claims 1 to 4, wherein the elastic part (11) is a bellows-shaped elastic body, and the probe pin (10) has a shape in which the first contact part provided with the first contact (25) and the second contact part provided with the second contact (34) are integrally molded so as to be reciprocable mutually via the elastic body.

8. The probe pin according to claim 7, wherein the integral elastic body and the first and second contact parts are electroformed products.

9. An electronic device comprising the probe pin according to any one of claims 1 to 8.