Test probe for finger tester and corresponding finger tester
View Patent ↗A test probe for a finger tester for the testing of non-componented circuit boards has a test needle with a probe tip which may be brought into contact with a circuit board test point, and which may be pivotably attached to a mount by means of at least two flexible sprung retaining arms. It is distinguished by the fact that at least one of the retaining arms is made of an electrically conductive material and is electrically connected to the test needle. In a corresponding finger tester, the test probe is driven by a linear motor.
1. Test probe for a finger tester for the testing of circuit boards, with no independent drive, the test probe comprising:
a test needle with a probe tip which may be brought into contact with a circuit board test point;
a mount; and
at least two pairs of flexible sprung retaining arms that pivotably attach the test needle to the mount,
wherein at least one of the retaining arms is made of an electrically conductive material and is electrically connected to the test needle,
wherein each pair of retaining arms is mounted in one plane, with one end fixed to the test needle and the other end to the mount, and each pair of retaining arms spanning legs of a triangle having at least a partially open interior when viewed from above and
wherein the length of the retaining arms further away from the probe tip viewed from the side is designated by the variable a, the length of the retaining arms closer to the probe tip by the variable b, the length of the test needle by the variable L, and the length of the section of the test needle between the respective retaining arms by the variable L 0 , and these length details satisfy the following relationship:
a
≈
b
(
1
-
tan
L
0
L
)
.
2. Test probe according to claim 1 , wherein both pairs of retaining arms comprise a retaining arm made of an electrically conductive material and are electrically connected to the test needle.
3. Test probe according to claim 2 , wherein the test needle is surrounded by a shield which is electrically connected to one or more of the retaining arms, which is electrically conductive and connected to earth and which pivotably attaches the test needle to the mount.
4. Test probe according to claim 1 , wherein the test needle is surrounded by a shield which is electrically connected to one or more of the retaining arms, which is electrically conductive and connected to ground and which pivotably attaches the test needle to the mount.
5. Test probe according to claim 4 , wherein the retaining arms span the shape of a trapezoid when viewed from the side.
6. Test probe according to claim 5 , wherein the retaining arm or arms which is or are closer to the probe tip is or are longer than the retaining arm(s) which is or are further from the probe tip.
7. Test probe according to claim 6 , wherein the retaining arms are surrounded, at least in part, by a shield element.
8. Test probe according to claim 7 , wherein a pre-tensioning element is provided, to pre-tension the retaining arms against the direction of contacting by a specific amount.
9. Test probe according to claim 8 , wherein a position sensor is provided to determine the position of the test needle relative to the mount.
10. Test probe according to claim 9 , wherein the position sensor has a photoelectric switch with an optical measuring section provided on the mount, and a vane to interrupt the optical measuring section provided on the test needle.
11. Test probe according to claim 10 , wherein the optical measuring section has a predetermined extent roughly at right-angles to the direction of movement of the test needle, and the vane has an interrupting edge running at an angle to the direction in which the optical measuring section extends.
12. Test probe according to claim 1 , wherein the retaining arms span the shape of a trapezoid when viewed from the side.
13. Test probe according to claim 12 , wherein the retaining arm or arms which is or are closer to the probe tip is or are longer than the retaining arm(s) which is or are further from the probe tip.
14. Test probe according to claim 1 , wherein the retaining arms are surrounded, at least in part, by a shield element.
15. Test probe according to claim 1 , wherein a pre-tensioning element is provided, to engage and pre-tension the retaining arms against the direction of contacting by a specific amount.
16. Test probe according to claim 1 , wherein a position sensor is provided to determine the position of the test needle relative to the mount.
17. Test probe for a finger tester for the testing of circuit boards, with no independent drive, and with a test needle with a probe tip which may be brought into contact with a circuit board test point, and which may be pivotably attached to a mount by means of at least two pairs of flexible sprung retaining arms,
wherein at least one of the retaining arms is made of an electrically conductive material and is electrically connected to the test needle, and
wherein each pair of retaining arms is mounted in one plane, with one end fixed to the test needle and the other end to the mount, and each pair of retaining arms spanning a triangle when viewed from above; and
further comprising a position sensor to determine the position of the test needle relative to the mount, wherein the position sensor has a photoelectric switch with an optical measuring section provided on the mount, and a vane to interrupt the optical measuring section provided on the test needle.
18. Test probe according to claim 17 , wherein the optical measuring section has a predetermined extent roughly at right-angles to the direction of movement of the test needle, and the vane has an interrupting edge running at an angle to the direction in which the optical measuring section extends.
19. Test probe for a finger tester for the testing of circuit boards, comprises a test needle with a probe tip for contacting a circuit board test point, the test needle being attached to a mount by at least two pairs of flexible sprung retaining arms,
wherein at least one of the retaining arms is electrically conductive and is electrically connected to the test needle,
wherein each pair of retaining arms is mounted in a different plane, with one end fixed to the test needle and the other end to the mount, and each pair of retaining arms spanning legs of a triangle having at least a partially open interior when viewed from above; and
wherein the length of the retaining arms further away from the probe tip viewed from the side is designated by the variable a, the length of the retaining arms closer to the probe tip by the variable b, the length of the test needle by the variable L, and the length of the section of the test needle between the respective retaining arms by the variable L 0 , and these length details satisfy the following relationship:
a
≈
b
(
1
-
tan
L
0
L
)
.
20. Test probe according to claim 19 , wherein both pairs of retaining arms comprise a retaining arm being constructed from an electrically conductive material and being electrically connected to the test needle.
21. Test probe according to claim 19 , wherein the test needle is surrounded by a shield which is electrically connected to one or more of the retaining arms, which is electrically conductive and connected to ground and which attaches the test needle to the mount.
22. Test probe according to claim 19 , wherein the retaining arms span the shape of a trapezoid when viewed from the side.
23. Test probe according to claim 19 , wherein the retaining arms are surrounded, at least in part, by a shield element.
24. Test probe according to claim 19 , wherein a pre-tensioning element is provided, to pre-tension the retaining arms against the direction of contacting by a specific amount.
25. Test probe according to claim 19 , wherein a position sensor is provided to determine the position of the test needle relative to the mount.
26. Test probe for a finger tester for the testing of circuit boards, comprises a test needle with a probe tip for contacting a circuit board test point, the test needle being attached to a mount by at least two pairs of flexible sprung retaining arms,
wherein at least one of the retaining arms is electrically conductive and is electrically connected to the test needle, and
wherein each pair of retaining arms is mounted in a different plane, with one end fixed to the test needle and the other end to the mount, and each pair of retaining arms spanning a triangle when viewed from above; further comprising a position sensor to determine the position of the test needle relative to the mount in which the position sensor has a photoelectric switch with an optical measuring section and a vane to interrupt the optical measuring section.
27. Test probe according to claim 26 , wherein the optical measuring section is provided on the mount and the vane is provided on the test needle.
28. A test probe for a finger tester for the testing of circuit boards, with no independent drive, the test probe comprising:
a test needle with a probe tip which may be brought into contact with a circuit board test point;
a mount; and
at least two pairs of flexible sprung retaining arms that pivotably attach the test needle to the mount,
wherein at least one of the retaining arms is made of an electrically conductive material and is electrically connected to the test needle, and
wherein each pair of retaining arms is mounted in one plane, with one end fixed to the test needle and the other end to the mount, and each pair of retaining arms spans legs of a triangle having at least a partially open interior when viewed from above,
wherein the lengths of the one pair of retaining arms further away from the probe tip are designated by variable a and when viewed from the side are shorter than the lengths of the other pair of the retaining arms that are closer to the probe tip and are designated by variable b.
29. A test probe according to claim 28, wherein both pairs of retaining arms comprise a retaining arm made of electrically conductive sheet metal and are electrically connected to the test needle.
30. A test probe according to claim 28, wherein the test needle is surrounded by a shield which is electrically connected to one or more of the retaining arms, which is electrically conductive and connected to ground.
31. A test probe according to claim 30, wherein the retaining arms span the shape of a trapezoid when viewed from the side.
32. A test probe according to claim 28, wherein the retaining arms span the shape of a trapezoid when viewed from the side.
33. A test probe according to claim 28, wherein the retaining arms are surrounded, at least in part, by a shield element.
34. A test probe according to claim 28, wherein a pre-tensioning element is provided to engage and pre-tension the retaining arms against the direction of contacting by a specific amount.
35. A test probe according to claim 28, wherein a position sensor is provided to determine the position of the test needle relative to the mount.
36. A test probe according to claim 28, wherein the sheet metal is between 50 and 200 micrometers in thickness.
37. A tester for testing a circuit board, comprising:
retaining elements for holding the circuit board;
several test heads that are positioned relative to the circuit board, each of the test heads comprising a test probe that is contacted with the circuit board, the test probe including:
a test needle with a probe tip which may be brought into contact with a circuit board test point;
a mount; and
at least two pairs of flexible sprung retaining arms that pivotably attach the test needle to the mount,
wherein at least one of the retaining arms is made of electrically conductive sheet metal and is electrically connected to the test needle, and
wherein each pair of retaining arms is mounted in one plane, with one end fixed to the test needle and the other end to the mount, and each pair of retaining arms spans legs of a triangle having at least a partially open interior when viewed from above.
38. A tester according to claim 37, wherein both pairs of retaining arms comprise a retaining arm being constructed from electrically conductive sheet metal and being electrically connected to the test needle.
39. A tester according to claim 38, wherein the test needle is surrounded by a shield which is electrically connected to one or more of the retaining arms, which is electrically conductive and connected to ground.
40. A tester according to claim 37, wherein the retaining arms span the shape of a trapezoid when viewed from the side.
41. A tester according to claim 37, wherein the retaining arms are surrounded, at least in part, by a shield element.
42. A tester according to claim 37, wherein a pre-tensioning element is provided, to pre-tension the retaining arms against the direction of contacting by a specific amount.
43. A tester according to claim 37, wherein a position sensor is provided to determine the position of the test needle relative to the mount.
44. A tester according to claim 37, wherein each pair of retaining arms is made from a single unitary piece of electrically conductive sheet metal.
45. A tester according to claim 37, wherein the sheet metal is between 50 and 200 micrometers in thickness.
46. A tester according to claim 37, wherein the retaining arms which are closer to the probe tip are longer than the retaining arms which are farther from the probe tip.