JP2004138592A - Spring contact and spring probe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spring contact, manufactured at a low cost, wherein a volute spring is used to remove unstable factors for stable contact. <P>SOLUTION: The spring contact comprises at least one volute spring which is wound in volute where an innermost portion protrudes most at normal time, with the tip part existing on a plane perpendicular to an axis, and the tip part of the volute spring directly contacts a prescribed contact surface. The spring contact is housed in a hole part which is cylindrical and hollow and formed at an insulator, and its tip protrudes from the surface of the insulator to directly contact a prescribed contact surface, constituting a single spring contact or a spring probe. The spring contact is used to constitute a spring probe for inspection, for a low-cost spring probe, etc. capable of stable inspection. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a spring contact, and more particularly to a structure of a spring contact using a bamboo leaf spring as a biasing element. This type of spring contact is often used for an inspection probe or an IC socket which is pressed against an object to be inspected or an electrode to be connected for electrical inspection, measurement and connection of a semiconductor element, an electronic device, a circuit board and the like. Can be
[0002]
[Prior art]
2. Description of the Related Art Conventionally, various probes have been used for inspection of various circuits and the like formed on a printed circuit board. This probe has a spring contact with a biasing element (spring), the tip of which is pressed against an electrode on the substrate and makes electrical contact with the electrode, so that the electrical state of the electrode (for example, from the electrode) This is used to detect the state of the output signal) or to input a predetermined signal thereto. On the other hand, a probe mechanism having a spring contact on the measurement side to make an electrical connection is also used.
[0003]
Some spring contacts constituting this type of probe mechanism use a coil spring as a biasing element (spring) (for example, see Patent Documents 1 and 2). Further, as a spring contact (probe), there is a spring contact using a bamboo spring as an urging element (for example, see Patent Document 3).
[0004]
[Patent Document 1]
JP-A-11-26112 (FIG. 1)
[Patent Document 2]
Japanese Patent Application Laid-Open No. 2000-357571 (P2000-357571A)
JP-A-9-178772 (FIGS. 3 to 6)
[0005]
The above-mentioned Patent Document 1 discloses a printed circuit board terminal that can be effectively used when developing a printed circuit board using an IC, inspecting a printed circuit board, and the like. FIG. 6 shows a printed circuit board terminal disclosed in [Patent Document 1]. The reference numerals in FIG. 6 are assigned according to the same document and do not correspond to other drawings in this specification. The printed circuit board terminal 10 is provided with a large number of stepped through-holes 6 having a small-diameter portion 6a on the upper side and a large-diameter portion 6b on the lower side in a prescribed arrangement in the thickness direction, and is provided outside the through-hole groups 6, 6,. A contact holding plate 1 having an insulating property and having a locking means 1b for fixing a predetermined lid-like body at a predetermined position, and the through-hole 6 shown in FIG. A sealing plate 5 including a contact whose upper end protrudes in the metal contact, a metal coil spring 3 for imparting springiness to the contact, and conductive pin groups 4, 4. Is mainly composed. As shown in FIG. 2A, an IC socket can be constituted by the IC holding lid 20 provided with the lid-side locking means 23. Descriptions of (d) and (e) are omitted here.
[0006]
In the technology disclosed in [Patent Document 1], the contact portion structure has a two-body structure of a compression coil spring and a contact (pin) (FIG. 6C) or a structure in which the contact is omitted. Since the compression coil spring (winding spring, coil spring) is used, the spring length is long. This means that the electrical length is long, which adversely affects the crosstalk characteristics, and is not suitable for transmission lines for high-frequency signals.
[0007]
Next, [Patent Document 2] discloses that a ball grid array (BGA) or land grid array (LGA) type surface mounting IC accommodated inside a BGA type is appropriately accommodated, and input / output terminals of the IC are mounted on a mounting printed board. An IC socket for connecting to the predetermined IC terminal connection electrode, and a connection terminal of the IC and a circuit outside the IC socket can be easily connected and input / output signals while the IC is housed. It discloses an IC socket that is possible, and particularly has a thin structure and high reliability. 7A and 7B show an IC socket disclosed in the document (the reference numerals in FIG. 7 are based on the document and do not correspond to other drawings).
[0008]
The IC socket 100 of the above-mentioned [Patent Document 2] includes a socket base made of an insulating material disposed in a connection area portion for an IC terminal at a predetermined position on a printed board surface, and a socket fixing for fixing the socket base to the printed board. Means, an external connection printed circuit board fixed to the upper surface of the socket base, and IC fixing means for pressing and fixing a BGA type IC placed at a predetermined position on the external connection printed circuit board from above, The socket base is individually urged inside the socket base at a position corresponding to the individual terminal position of the BGA type IC mounted and housed on the upper surface thereof, from the upper surface of the socket base via the through hole of the external connection printed circuit board. An upper contact pin group 12 configured to project by a certain amount, and each of the upper contact pin groups is electrically connected to each of the upper contact pin groups. And a lower contact pin group 11 configured to be individually urged inside the cage base to be electrically connected to the lower surface of the socket base at a position corresponding to the IC terminal connection electrode provided on the mounting printed circuit board. The external connection printed circuit board has a through hole through which the upper contact pin group is individually inserted, and is individually electrically connected to the upper contact pin group and extends to the outer edge on the surface of the external connection printed circuit board. It is configured to include the surface wiring portions that are provided and insulated from each other. As a result, a small, thin BGA terminal IC socket capable of inputting and outputting signals to and from the outside is realized.
[0009]
The upper contact pin and the lower contact pin forming a pair shown in FIG. 7B are coaxially arranged, and are urged in a direction away from each other by urging means. In particular, in the socket base, a plurality of through holes having a constant diameter at an upper portion and a small diameter at a lower portion and having a step portion are formed in a predetermined arrangement in a thickness direction. On the other hand, a conductor land to which one end of the wiring portion is individually connected is formed on the surface at a position corresponding to the through hole in a specified mounting state, and a land having a diameter smaller than the predetermined diameter is formed at a substantially central position of the land. A through-hole is formed, the lower contact pin has a flange at the axial middle part, and the upper contact pin has a flange at the axial middle part, and between the flanges. A lower end of the lower contact pin is urged by the repulsive force of the coil spring and is coaxially accommodated in the through-hole with a coil spring in a compressed and deformed state interposed therebetween. From the upper contact pin Protrudes from the upper surface of the connection printed circuit board.
[0010]
One of the upper contact pin or the lower contact pin has a shaft extending axially inward from the flange, and the other contact pin extends axially inward from the flange. A tubular portion for accommodating the shaft portion in a slidable or loosely fitted state, wherein the coil spring is mounted on an outer periphery of the shaft portion and the tubular portion, and both ends of the both flange portions Are in contact with each other.
[0011]
In addition, an inner cylindrical member slidably mounted on an outer periphery of an axially outer portion of the upper contact pin from the flange portion and having a flange portion formed on an axially outer end portion, and an inner cylindrical member positioned on the outer periphery of the inner cylindrical member. There is also disclosed a structure including a second coil spring which is disposed in a compressed state by bringing both ends into contact with the flange portion of the contact pin and the flange portion of the inner cylindrical member with a biasing force weaker than that of the coil spring. ing. The connection between the contact pin portion and the land of the external connection printed circuit board is ensured. However, since the disclosed technology of the above-mentioned [Patent Document 2] also uses a compression coil spring (winding spring, coil spring), transmission of a high-frequency signal such as a long spring length and thus a long electrical length adversely affects crosstalk characteristics. Not suitable for the road.
[0012]
FIG. 8 shows the spring probe of the above-mentioned [Patent Document 3] (the reference numerals in the figure correspond to those in the document, and do not correspond to other drawings). This spring probe has a rod-shaped plunger whose distal end portion is pressed against and contacts an object to be inspected, a tubular barrel that accommodates the plunger portion with its distal end protruding, and a spiral barrel wound as a whole and having an outer diameter side of the barrel. It has a bamboo leaf spring fixed to the inner peripheral portion and having an inner diameter side fixed to the outer peripheral portion of the plunger and elastically supporting the plunger to be able to advance and retreat with respect to the barrel.
[0013]
When the spring probe is used, the tip of the plunger 1 is pressed against a desired electrode on a printed circuit board, which is an object to be inspected. As a result, the plunger 1 retracts in the barrel 2 according to the pressing force, but the coil spring 3 presses the plunger 1 toward the distal end. Then, the tip 1a of the plunger 1 is pressed against the electrode. Since the plunger 1, the barrel 2, and the coil spring 3 are all made of a conductive metal material, electrical continuity between the electrode and an inspection device supporting the probe is established via the probe, and various An inspection is performed. In this probe, a current basically flows through the plunger 1, the coil spring 3, and the barrel 2.
[0014]
In the spring probe using the above-mentioned bamboo shoot spring, since the bamboo shoot spring is used as a substitute for the compression coil spring, the overall contact structure has at least three components. In order to further reduce costs, it is desired to reduce the number of parts, thereby reducing the number of assembly steps and enabling low-cost production.
[0015]
[Problems to be solved by the invention]
As described above, most of the spring contacts or spring probes are composed of a large number of components, and have a drawback that the assembly is complicated and requires a corresponding manufacturing cost. Further, those using a spring coil as the urging means generally have a drawback that the electrical length is long and the crosstalk characteristics are adversely affected.
[0016]
The present invention has been made in view of the current situation of the spring probe as described above, and an object of the present invention is to provide a spring contact that uses a bamboo shoot spring, eliminates unstable factors, provides stable contact, and can be manufactured at low cost. And If an inspection spring probe is configured using this spring contact, a low-cost spring probe that can perform stable inspection can be obtained.
[0017]
[Means for Solving the Problems]
In order to solve the problem, in the present invention, the spring contact includes at least one bamboo shoot spring, and in a normal state, the spring contact spirally winds in a shape protruding toward the front end side toward the inside, and the front end portion is formed. It is formed so as to lie on a plane perpendicular to the axis, and the tip is configured to directly contact a predetermined contact surface.
[0018]
Alternatively, in a spring probe having a spring contact configured to include at least one bamboo shoot spring, the spring contact is wound in a spiral shape in a normal state so as to protrude toward the distal end side inward, and the distal end portion is attached to the shaft. The spring contact is housed in a hollow cylindrical hole formed in an insulator, and the tip portion projects from the insulator surface to directly contact a predetermined contact surface. The spring probe is configured to have
[0019]
By using a configuration in which the bamboo saw spring is in direct contact with the connection target, the number of parts is reduced and cost is reduced. When a bamboo spring is used, when the tip of the contact or the probe is pushed down, the spiral spring is pushed out. For this reason, the inside and outside of the spring come into contact with each other, and a pressing force is applied to a contact point with an opposing member such as a plunger, so that the contact can be made with a high contact pressure. Also, by pushing down the tip of the bamboo shoot spring, the tip of the spiral spring is pushed out and expanded, the tip of the bamboo shoot spring rotates, the wiping effect is added to the contact, and the contact is always kept clean and stable. A good electrical connection is obtained.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
[First Embodiment] Hereinafter, the present invention will be described in detail with reference to the drawings by way of embodiments. 1A and 1B show a schematic configuration of a spring contact as a first embodiment of the present invention, wherein FIG. 1A is a cross-sectional view, FIG. 1B is a partial cross-sectional side view of a bamboo shoot spring, and FIG. is there. A spring contact 500A of this embodiment has a hollow cylindrical metal barrel 100 having a bottom and one end 100a opened, and is housed and arranged inside the barrel 100 and has a tip 200a from the opening 100a of the barrel. It is composed of two parts, a bamboo shoot spring 200A arranged so as to protrude slightly.
[0021]
The bamboo shoot spring 200A arranged in the barrel 100 spirally winds a thin strip-shaped metal plate (strip-shaped material) having a sufficient elasticity and a predetermined width W into a shape protruding inward toward the front end in a normal state. The tip portion 200a is formed so as to be horizontal in the drawing, that is, so that the tip edge portion has a circumferential shape on a plane perpendicular to the axis. Similarly, the lower end portion (base end portion) 200a of the bamboo leaf spring is formed in a circumferential shape that is horizontal in the figure. In this embodiment, after a strip-shaped metal plate having a width W is formed in a predetermined shape while being shifted in the axial direction (vertical direction) in a coaxial spiral shape, the upper end (tip) and the lower end (base end) are formed to have a predetermined length. It is cut so that the cut surface is perpendicular to the axis, and formed into a desired shape as shown in the figure. In the bamboo shoot spring 200A of the embodiment, the front and back curved surfaces of the band-shaped material substantially adhere to each other when compressed in the vertical direction. For the bamboo shoot spring, a known material such as brass or beryllium copper may be used, and gold plating is performed as necessary.
[0022]
The barrel 100 is formed with a rod-shaped mounting extension 100c having a smaller diameter than the center of the bottom surface 100b of the main body. In this embodiment, the bamboo leaf spring 200A is sealed by inserting the bamboo leaf spring 200b into the barrel and then crimping the barrel distal end portion 100d to deform the tapered leaf spring taper as shown. At this time, the bamboo leaf spring 200A may be inserted and fixed by inserting a bamboo leaf spring 200A using a conductive adhesive material, or the bamboo leaf spring 200A may be provided in the inner space of the barrel by defining the outer diameter of the bamboo leaf spring 200A on the base end side. May be inserted and accommodated and fixed. In this case, it is possible to omit the caulking deformation of the barrel tip after the housing, but it is preferable to caulk. The barrel may be made of a known material such as brass, for example, and may be plated with gold as needed.
[0023]
Although it is disadvantageous in terms of cost as another configuration method, the barrel may be configured to be vertically splittable. The tip of the upper member of the barrel is tapered in advance. Then, in a divided state, the bamboo shoot spring 200A is housed in the lower member of the barrel, and then the upper member is joined (for example, screwed).
[0024]
When such a spring contact is used, the base end side of the spring contact is erected at a predetermined position of a predetermined member (a printed circuit board, a tip of an inspection probe of an inspection device, or the like) by the attachment extension 100c. Then, the tip of the spring contact 100 (that is, the tip 200a of the bamboo shoot spring 200A) is pressed against the electrode of the measured object. As a result, a pressing force F is applied in the direction of the arrow, and the tip of the bamboo shoot spring moves downward in the barrel. Then, the inside of the bamboo leaf spring 13 moves downward in the drawing, and the tip of the bamboo leaf spring is urged upward by the repulsive force generated at this time. Thus, the tip 200a of the bamboo leaf spring 200A is pressed against the electrode with a desired pressure. Here, the bamboo shoot spring 13 and the barrel 12 are both formed of a conductor, and an inspection device or the like supporting a spring contact is conductively connected to the electrode 20. Therefore, the inspection device can inspect the electrical state of the electrode 20. In addition, a predetermined signal can be supplied from the inspection device to the electrode 20.
[0025]
According to the above-described embodiment, more stable contact can be obtained by pressing the spring contact than before. Electrical connection between the barrel and the bamboo spring is made at the base end of the bamboo spring and is fixed, there is no sliding moving portion, the electrical length is short, and the performance such as crosstalk is good. Even if the bamboo shoot spring is deformed and the tip moves, the electrical conduction path in the probe does not substantially change. In addition, when the bamboo leaf spring is deformed, the tip is pushed outward and rotated along the long axis, and a wiping effect is added to the contact, so that the contact is always kept clean.
[0026]
[Second Embodiment] FIG. 2 is a cross-sectional view showing a second embodiment of the spring contact according to the present invention. A plurality of spring contacts are arranged on a single insulating member (insulator 300A) to constitute a spring probe for inspection. One of these is illustrated. A plurality of spring contacts 500B of this embodiment are arranged in a predetermined arrangement on a substantially plate-shaped insulator made of an insulating material such as a heat-resistant polymer as shown in the above-mentioned [Patent Document 1] (see FIG. 6). It is used when an inspection probe is configured by being fixed to the formed hole.
[0027]
In the insulator 300A, a large number of hollow bottomed cylindrical holes 300a having a small diameter through hole on the upper side in FIG. In each hole 300a, a bamboo shoot spring 200B, which is substantially the same as that of the previous embodiment (see FIGS. 1B and 1C), is inserted from the bottom in the figure with its tip 200a facing upward, and furthermore, metal A pin 400 is inserted and fixed, and the bamboo leaf spring 200B is enclosed and fixed. The tip 200a of the bamboo shoot spring 200B slightly protrudes from the upper surface of the insulator 300A. As described above, each spring contact 500B is composed of two parts: the pin 400 and the bamboo shoot spring 200B whose tip is slightly protruded from the small-diameter opening in the upper surface of the insulator.
[0028]
The bamboo shoot spring 200B shown in FIG. 3 (partial cross-sectional side view (a) and axial cross-sectional view (b)) disposed in the insulator 300A of this embodiment has a thin band shape having a predetermined width W and sufficient elasticity. In a normal state, a metal plate (a belt-shaped material) is spirally wound so as to protrude toward the front end side toward the inner side, and the inner peripheral end 200c is formed at a substantially right angle toward the center of the winding shaft. It is bent. The tip 200a of the bamboo leaf spring 200B is formed so as to be horizontal in the drawing, that is, the tip edge is on a plane perpendicular to the axis. Incidentally, the lower end portion (base end portion) of the bamboo shoot spring is formed in a circumferential shape that is horizontal in the figure as in the previous embodiment. In the bamboo spring 200B of this embodiment, the same operation and effect as those of the previous embodiment are obtained, and the end face of the tip portion 200a is wider than that of the previous embodiment, and the contact performance is improved. By replacing the insulator with a small-diameter cylindrical member, a single independent spring contact can be formed.
[0029]
Third Embodiment FIG. 4 is a cross-sectional view showing a third embodiment of the spring contact according to the present invention. As in the second embodiment, the spring contact 500C of this embodiment can also be used to form a plate-like connecting member by being fixed to a plurality of holes formed in a predetermined arrangement on a substantially plate-like insulator. In the case of this embodiment, it is used by being interposed between upper and lower electrodes for electrical connection (for example, see FIG. 7). In addition, it can also be comprised as a single spring contact. The insulator 300B of the present embodiment is configured by integrally fixing two upper and lower plate-shaped components. That is, the insulator 300B is located at the top in the figure and has an upper insulator 300m formed with a bottomed space having a small diameter through-hole at the upper side, and the insulator 300B is located at the bottom in the figure. The lower insulator 300n is formed at a position corresponding to each of the bottomed spaces, and has a bottomed space having a small-diameter through hole on the lower side. Therefore, the insulator 300B has a large number of hollow cylindrical holes that are opened with small diameters at the top and bottom.
[0030]
A bamboo shoot spring 200B similar to that of the previous embodiment (see FIG. 3) is disposed in each of the holes, with the distal end thereof facing upward, and below the bamboo shoot spring 200B in contact with the base end portion 200b of the bamboo shoot spring 200B. The plunger 400A is enclosed with its tip directed downward. The tip of the bamboo shoot spring slightly projects from the upper surface of the insulator 300B, and the tip of the plunger 400A slightly projects from the lower surface of the insulator 300B. As described above, each of the spring contact main portions includes the bamboo shoot spring 200B whose tip is slightly protruded from the small-diameter opening on the upper surface of the insulator, and the plunger 400A whose tip is slightly protruded from the small-diameter opening on the lower surface of the insulator. It is composed of two parts. The function and the like of the spring contact 500C are the same as those of the previous embodiment, and the description is omitted.
[0031]
Fourth Embodiment FIG. 5 is a cross-sectional view showing a fourth embodiment of the spring contact according to the present invention. The function and use of the spring contact 500D of this embodiment are the same as those of the third embodiment. The insulator 300B constituting the spring contact 500D has the same configuration as the third embodiment, and has a large number of hollow cylindrical holes which are fixed to the upper and lower two plate-like parts and are open at the top and bottom with small diameters. I have.
[0032]
In each hole of the insulator 300B, two bamboo shoot springs 200B similar to the previous embodiment (see FIG. 3) are sealed in opposite directions. The upper bamboo leaf spring 200B is disposed with its distal end 200a facing upward, and the same bamboo leaf spring 200B is disposed below it with its distal end 200a facing downward. In contact. The tip 200a of each of the bamboo leaf springs 200B, 200B slightly protrudes from the upper surface and the lower surface of the insulator 300B.
[0033]
As described above, each spring contact main portion is constituted by two bamboo shoot springs 200B (two parts) whose tips slightly protrude from the small-diameter openings on the upper and lower surfaces of the insulator. The function and the like of the spring contact 500D are exactly the same as in the previous embodiment. In the case of such a form, the outer peripheral end may be bent at substantially a right angle toward the center of the winding shaft on the basal end side of both bamboo leaf springs as well as the distal end side. The contact between them is increased.
[0034]
As described in the above several embodiments, according to the present invention, a stable contact can be obtained by using a bamboo-spring, and a short electric length and good crosstalk characteristics can be obtained. It is possible to manufacture a spring contact that can be manufactured at a low cost with a small manufacturing process. If such a spring contact is used, a low-cost spring probe can be obtained.
[0035]
The above embodiments are merely examples, and different spring contacts can be formed by appropriately combining the elements shown in the embodiments. In addition, individual components are not limited to the embodiments, and can be changed within the scope of the invention.
[0036]
【The invention's effect】
As described above, according to the present invention, a stable contact and crosstalk characteristics can be obtained at a low cost by using the special bamboo spring as described above and forming the spring contact main part in two parts. A manufacturable spring contact can be obtained, and by using this, a spring probe with similarly good performance and low cost can be obtained.
[Brief description of the drawings]
1A and 1B are diagrams showing a configuration of a first embodiment of a spring contact according to the present invention, wherein FIG. 1A is a cross-sectional view, FIG. 1B is a partial cross-sectional side view of a bamboo shoot spring, and FIG. is there.
FIG. 2 is a cross-sectional view showing a configuration of a second embodiment of the spring contact of the present invention.
FIGS. 3A and 3B are a partial sectional side view (a) and an axial sectional view (b) of a bamboo shoot spring according to the present invention.
FIG. 4 is a cross-sectional view showing a configuration of a third embodiment of the spring contact of the present invention.
FIG. 5 is a cross-sectional view showing the configuration of a fourth embodiment of the spring contact of the present invention.
FIGS. 6A to 6E are diagrams illustrating a printed circuit board terminal including a known spring contact.
FIG. 7 is a diagram ((a), (b)) for explaining an IC socket configured to include a known spring contact for connecting to an IC terminal connection electrode.
FIG. 8 is a diagram ((a) to (c)) for explaining a known spring probe.
[Explanation of symbols]
100 Barrel 100a Opening 100b Bottom surface 100c Mounting extension 100d Barrel tip 200A, 200B Bamboo leaf spring 200a Tip 200b Base end 200c Inner end 300A, 300B Insulator 300a ... hole 300m ... upper insulator 300n ... lower insulator 400 ... pin 400A ... plunger 500A, 500B, 500C, 500D ... spring contact

Claims (2)

In a spring contact configured to include at least one bamboo shoot spring,
In a normal state, the spring contact is spirally wound in such a manner as to protrude toward the front end side toward the inside, and is formed such that the front end portion is on a plane perpendicular to the axis. A spring contact characterized in that it comes into direct contact with a surface. In a spring probe having a spring contact configured to include at least one bamboo shoot spring,
The spring contact, in a normal state, is spirally wound into a shape protruding toward the distal end toward the inside, and is formed such that the distal end portion is on a plane perpendicular to the axis,
A spring probe, wherein the spring contact is accommodated in a hollow cylindrical hole formed in an insulator, and the tip portion is made to protrude from a surface of the insulator so as to directly contact a predetermined contact surface.

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