FORCE BIASED SPRING PROBE PIN ASSEMBLY

Abstract

A force biased spring probe pin assembly includes a barrel member having a barrel wall defining an elongate internal cavity with a lower end and an upper end. The assembly also includes a split plunger member comprised of an upper split plunger part separated from a lower split plunger part separated by a diagonal cut reciprocally mounted in the internal cavity proximate the lower end of the internal cavity. A spring member is positioned in the internal cavity between the upper split plunger part and the second end of the internal cavity. A force biased spring probe pin assembly includes a barrel member having a barrel wall defining an elongate internal cavity with a lower end and an upper end. The assembly also includes a first split plunger member reciprocally mounted in the internal cavity proximate the lower end of the internal cavity and a second split plunger member reciprocally mounted in the internal cavity proximate the upper end of the internal cavity. The first and second split plunger members are each comprised of two parts: a first upper plunger part separated from a first lower plunger part by a diagonal cut. A spring member is positioned in the internal cavity between the first and second upper split plunger parts. In each split plunger the diagonal surface of the upper split plunger part exerts a transverse force to the diagonal surface of the lower split plunger part ensuring good electrical contact between the lower split plunger member part and the barrel wall.

Claims

1. A force biased spring probe pin assembly comprising: a barrel member having a barrel wall defining an elongate internal cavity with a lower end and an upper end; a first split plunger member reciprocally mounted in said internal cavity proximate said lower end of said internal cavity wherein said first split plunger member is further comprised of an upper split plunger member part and a lower split plunger member part separated by a diagonal cut; and a spring member positioned in said internal cavity between said split plunger member and said second end of said internal cavity.

2. The assembly of claim 1, wherein the spring probe pin assembly is a Pogo assembly.

3. The assembly of claim 1, said upper split plunger member part being in Continuous contact with said lower split plunger member part and said lower split plunger member part in continuous contact with said barrel wall.

4. The assembly of claim 1, further comprising a second split plunger member reciprocally mounted in said internal cavity proximate said second end, wherein said second split plunger member is further comprised of an upper split plunger member part and a lower split plunger member part separated by a diagonal cut.

5. The assembly of claim 4, said cylindrical cavity having a first opening at said first end and a second opening at said second end, said first split plunger member comprising a first probe pin extending through said first opening and said second probe member comprising a second probe pin extending through said second opening.

6. The assembly of claim 1, wherein an angle between said diagonal cut and said cylindrical barrel member is between about 5 degrees and 25 degrees.

7. The assembly of claim 1, wherein an angle between said diagonal cut and said cylindrical barrel member is about 10 degrees.

8. The assembly of claim 1 further including an insert positioned between said upper split plunger member and said spring wherein said insert is comprised of non conductive material.

9. The assembly of claim 1 wherein said upper split plunger member part is comprised of non conductive material.

10. A force biased spring probe pin assembly comprising: a barrel member having a barrel wall defining an elongate internal cavity with a lower end and an upper end; a first split plunger member reciprocally mounted in said internal cavity proximate said lower end of said internal cavity wherein said first split plunger member is further comprised of a first upper split plunger member part and a first lower split plunger member part separated by a diagonal cut; a second split plunger member reciprocally mounted in said internal cavity proximate said upper end of said internal wherein said second split plunger member is further comprised of a second upper split plunger member part and a second lower split plunger member part separated by a diagonal cut; and a spring member positioned in said internal cavity between said first upper split plunger member part and said second upper split plunger member part;

11. The assembly of claim 10, wherein the spring probe pin assembly is a Pogo assembly.

12. The assembly of claim 10, with a diagonal surface of said first upper split plunger member part being in continuous contact with and applying transverse force to a diagonal surface of said first lower split plunger member part and said first lower split plunger member part in continuous contact with said barrel wall and with a diagonal surface of said second upper split plunger member part being in continuous contact with and applying transverse force to a diagonal surface of said second lower split plunger member part and said second lower split plunger member part in continuous contact with said barrel wall.

13. The assembly of claim 10, said cylindrical cavity having a first opening at said first end and a second opening at said second end, said first split plunger member comprising a first probe pin extending through said first opening and said second probe member comprising a second probe pin extending through said second opening.

14. The assembly of claim 10, wherein an angle between said first diagonal cut and said cylindrical barrel member is between about 5 degrees and 25 degrees.

15. The assembly of claim 10, wherein an angle between said first diagonal cut and said cylindrical barrel member is about 10 degrees.

16. The assembly of claim 10 further including an insert positioned between at least one of said first and said second upper split plunger member and said spring wherein said insert is comprised of non conductive material.

17. The assembly of claim 10 wherein said at least one of said first and second upper split plunger member part is comprised of non conductive material.

Description

DESCRIPTION OF THE VIEWS OF THE DRAWINGS

[0012] FIG. 1 (Prior art) is a partially transparent view of a prior art single ended spring probe pin assembly.

[0013] FIG. 2 (Prior art) is a partially transparent view of a prior art dual ended spring probe pin assembly.

[0014] FIG. 3 (Prior art) is a partially transparent view of a failed prior art spring probe pin assembly.

[0015] FIG. 4 is a partially transparent view of an example embodiment of a force-biased spring probe pin assembly with a two piece (split) plunger.

[0016] FIGS. 5A and 5B are a partially transparent expanded views of the two piece (split) plunger in FIG. 4.

[0017] FIG. 6 is a partially transparent view of an embodiment force-biased dual ended spring probe pin assembly with two piece (split) plungers.

[0018] FIG. 7 is a partially transparent view of an example embodiment of a force-biased spring probe pin assembly where the upper part of the two piece (split) plunger is made of non conductive material.

[0019] FIG. 8 is a partially transparent view of an example embodiment of a force-biased spring probe pin assembly with an insert made of non conductive material positioned between the spring and the upper part of the two piece (split) plunger.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0020] Embodiments of the invention are described with reference to the attached figures. The figures are not drawn to scale and they are provided merely to illustrate the invention. Several aspects of the embodiments are described below with reference to example applications for illustration. It should be understood that numerous specific details, relationships, and methods are set forth to provide an understanding of the invention. One skilled in the relevant art, however, will readily recognize that the invention can be practiced without one or more of the specific details or with other methods. In other instances, well-known structures or operations are not shown in detail to avoid obscuring the invention. The embodiments are not limited by the illustrated ordering of acts or events, as some acts may occur in different orders and/or concurrently with other acts or events. Furthermore, not all illustrated acts or events are required to implement a methodology in accordance with the present invention.

[0021] Embodiment force-biased spring probe pin assemblies, 400 and 600, are illustrated in FIG. 4 and FIG. 6. FIG. 4 is an embodiment force-biased single ended spring probe pin assembly 400 with a split probe plunger comprised of a lower split plunger member 404 and an upper split plunger member 405 separated by a diagonal cut 407. FIG. 6 is an embodiment force-biased dual ended spring probe assembly 600 with a first split probe member, 404 and 405, and second split probe member, 604 and 605.

[0022] As shown in FIG. 4, the embodiment force biased spring probe pin assembly 400 may have one movable probe pin 402 attached to a first split plunger member 404 at one end of the cylindrical barrel member 406 and an immovable pin 410 attached to a closed end of the cylindrical barrel member 406. The movable probe pin 402 is attached to a lower plunger member part, 404. The plunger member is comprised of two parts: a lower plunger member part 404 and an upper member part 405 which are separated from each other by a diagonal cut 407. The split plunger member is reciprocally mounted in the cylindrical barrel member 406. A spring 408 positioned within the cylindrical barrel member 406 applies a downward force to the top of the upper split plunger member part 405. When the movable probe pin 402 contacts a probe pad of an integrated circuit, the split plunger member moves within the cylindrical barrel member 406 causing the spring 408 to compress. There may be hundreds of force biased spring probe pin assemblies in a probe head. The springs 408, split plunger member, and movable probe pin 402 enables hundreds of the movable probe pins 402 to simultaneously form good electrical contact to hundreds of probe pads on an integrated circuit with minimum damage to the probe pads.

[0023] When the spring 408 applies a downward force to the upper split plunger member part 405, the surface of the diagonal cut 407 applies a transverse force to the diagonal surface of the lower split plunger member part 404 which ensures good electrical contact between the lower split plunger member part 404 and the cylindrical barrel member 406. The angle of the diagonal cut 509 may be made shallower as shown in FIG. 5A to reduce the transverse force or steeper 507 as shown in FIG. 5B to increase the transverse force. The edges on the surfaces of the diagonal cuts on the upper and lower split plunger member parts 404 and 405 may be rounded to ensure smooth movement of the upper 405 and lower 404 split plunger parts against the inner walls of the cylindrical barrel member 406. The angle between the diagonal cut 407 and the wall of the cylindrical barrel member is typically between about 5 degrees and 25 degrees. In a preferred embodiment the angle is about 10 degrees.

[0024] As shown in FIG. 6, the embodiment force biased spring probe pin assembly may have one movable probe pin 402 attached to a first lower split plunger member part 404 at one end of the cylindrical barrel member 406 and a second movable probe pin 602 attached to a second lower split plunger member part 604 at the other end of the cylindrical barrel member 406. A spring 408 positioned in the cylindrical barrel member 406 applies an upward force to the second upper split plunger member part 605 and downward force to the first upper split plunger member part 405. The transverse force applied along the diagonal cuts, 407 and 607, between the upper split plunger member parts, 405 and 605, and the lower split plunger member parts, 404 and 604, ensures good electrical contact to probe pads on integrated circuits with minimal damage to the probe pads.

[0025] As is illustrated in FIG. 7, the upper split plunger part 705 may be formed of a nonconductive material to reduce the chance of significant current flowing through and damaging the spring 408.

[0026] Optionally as is illustrated in FIG. 8, a cap 805 of non conductive material may be positioned between the upper split plunger part 405 and the spring 408 to reduce the chance of significant current flowing through and damaging the spring 408

[0027] While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only and not limitation. Numerous changes to the disclosed embodiments can be made in accordance with the disclosure herein without departing from the spirit or scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above described embodiments. Rather, the scope of the invention should be defined in accordance with the following claims and their equivalents.