US4583042A — Capacitive circuit board testing system and metho…

Claim 1

Independent Claim 163 words

The method of testing electrical continuity and/or integrity of line segments on circuit boards having n test points where "n" is any whole integer by capacitance measurements comprising: (a) positioning the circuit board to be tested on a conductive pliant elastomeric backside reference plane with the circuit board backside surface in face-to-face relation with the conductive pliant elastomeric backside reference plane; (b) pressing the circuit board into mutually coextensive face-to-face contact with the conductive pliant elastomeric reference plane with the interface therebetween being devoid of any air gaps irrespective of non-planar irregularities on the circuit board; (c) coupling the first sensory terminal of a capacitance measuring device to the conductive pliant elastomeric reference plane; (d) coupling the second terminal of the capacitance measuring device to a test probe; and, (e) sequentially contacting the n test points with the probe to measure the capacitance of the line segments on the circuit board between the n test points and the conductive pliant elastomeric reference plane.

Claim 2

Independent Claim 163 words

The method of testing electrical continuity and/or integrity of line segments on circuit boards having n test points where "n" is any whole integer by capacitance measurements comprising: (a) positioning the circuit board to be tested on a conductive pliant elastomeric backside reference plane with the circuit board backside surface in face-to-face relation with the conductive pliant elastomeric backside reference plane; (b) pressing the circuit board into mutually coextensive face-to-face contact with the conductive pliant elastomeric reference plane with the interface therebetween being devoid of any air gaps irrespective of non-planar irregularities on the circuit board; (c) coupling the first sensory terminal of a capacitance measuring device to the conductive pliant elastomeric reference plane; (d) coupling the second terminal of the capacitance measuring device to a test probe; and, (e) sequentially contacting the n test points with the probe to measure the capacitance of the line segments on the circuit board between the n test points and the conductive pliant elastomeric reference plane.

Claim 3

Dependent Claim 45 words

The method of testing electrical continuity and/or integrity of line segments on circuit boards as set forth in claim 1 wherein a thin flexible sheet of insulating material is interposed between the backside surface of the circuit board and the conductive pliant elastomeric reference plane.

Claim 4

Dependent Claim 29 words

The method of testing electrical continuity and/or integrity of line segments on circuit boards as set forth in claim 2 wherein the circuit board is a double-sided circuit board.

Claim 5

Dependent Claim 69 words

The method of testing electrical continuity and/or integrity of line segments on circuit boards as set forth in claim 1, 2 or 3 wherein a vacuum is applied to the backside of the circuit board through the conductive pliant elastomeric reference plane for drawing the circuit board into intimate mutually coextensive face-to-face relation with the conductive pliant elastomeric reference plane and devoid of air gaps at the interface therebetween.

Claim 6

Independent Claim 34 words

The method of testing electrical continuity and/or integrity of line segments on circuit boards as set forth in claims 1, 2 or 3 wherein the capacitance measuring device comprises a three point capacitance meter.

Claim 7

Independent Claim 42 words

The method of testing electrical continuity and/or integrity of line segments on circuit boards as set forth in claims 1, 2 or 3 wherein the capacitance measuring device comprises a four point capacitance meter and the test probe comprises a two-point probe.

Claim 8

Dependent Claim 197 words

In an apparatus for testing the electrical continuity and/or integrity of line segments on a circuit board having n test points where "n" is any whole integer, the improvement comprising, in combination: (a) a test stand support; (b) means defining a conductive pliant elastomeric backside reference plane mounted on said support; (c) means mounted on said support for pressing a circuit board to be tested into intimate, mutually coextensive face-to-face engagement with said conductive pliant elastomeric backside reference plane with said conductive pliant elastomeric reference plane conforming in configuration to the backside configuration of the circuit board and being devoid of air gaps at the interface therebetween; (d) capacitance measuring means having first and second sensory terminals with one of said first and second sensory terminals coupled to said conductive pliant elastomeric backside reference plane; (e) means defining a test probe coupled to the other of said first and second sensory terminals; and, (f) means for moving said probe relative to said circuit board for sequentially contacting each of the n test points thereon to provide a measurement of line segment capacitance between each of the n test points and said conductive pliant elastomeric backside reference plane.

Claim 9

Dependent Claim 197 words

In an apparatus for testing the electrical continuity and/or integrity of line segments on a circuit board having n test points where "n" is any whole integer, the improvement comprising, in combination: (a) a test stand support; (b) means defining a conductive pliant elastomeric backside reference plane mounted on said support; (c) means mounted on said support for pressing a circuit board to be tested into intimate, mutually coextensive face-to-face engagement with said conductive pliant elastomeric backside reference plane with said conductive pliant elastomeric reference plane conforming in configuration to the backside configuration of the circuit board and being devoid of air gaps at the interface therebetween; (d) capacitance measuring means having first and second sensory terminals with one of said first and second sensory terminals coupled to said conductive pliant elastomeric backside reference plane; (e) means defining a test probe coupled to the other of said first and second sensory terminals; and, (f) means for moving said probe relative to said circuit board for sequentially contacting each of the n test points thereon to provide a measurement of line segment capacitance between each of the n test points and said conductive pliant elastomeric backside reference plane.

Claim 10

Dependent Claim 27 words

Apparatus as set forth in claim 7 further including a thin flexible sheet of insulating material overlying said means defining said conductive pliant elastomeric backside reference plane.

Claim 11

Dependent Claim 33 words

Apparatus as set forth in claims 7 or 8 further including a non-conductive board having an upwardly facing conductive surface thereon interposed between said support and said conductive pliant elastomeric backside reference plane.

Claim 12

Dependent Claim 85 words

Apparatus as set forth in claims 7 or 8 further including a non-conductive board having upwardly and downwardly facing conductive surfaces thereon and defining a through opening therein sized to receive the circuit board to be tested, said non-conductive board being disposed above and upon said conductive pliant elastomeric reference plane with said downwardly facing conductive surface in electrical contact with said conductive pliant elastomeric reference plane, and means for securing said board, conductive pliant elastomeric reference plane and support in a rigid sandwich-like configuration.

Claim 13

Dependent Claim 89 words

Apparatus as set forth in claim 9 further including a non-conductive board having upwardly and downwardly facing conductive surfaces thereon and defining a through opening therein sized to receive the circuit board to be tested, said non-conductive board being disposed above and upon said conductive pliant elastomeric reference plane with said downwardly facing conductive surface in electrical contact with said conductive pliant elastomeric reference plane; and, means for securing said first named and last named non-conductive boards, conductive pliant elastomeric reference plane and support in a rigid sandwich-like configuration.

Claim 14

Dependent Claim 79 words

Apparatus as set forth in claims 7 or 8 wherein said means for pressing the circuit board to be tested into intimate mutually coextensive face-to-face engagement with said conductive pliant elastomeric reference plane comprises a vacuum system including a vacuum chamber, vacuum communicating means extending from said chamber through said conductive pliant elastomeric reference plane, and means for establishing a vacuum in said chamber to draw the circuit board deposited on said reference plane into intimate face-to-face engagement therewith.

Claim 15

Dependent Claim 42 words

Apparatus as set forth in claims 7 or 8 wherein said capacitance measuring means comprises a three point capacitance meter having a first sensory terminal connected to said probe and a second sensory terminal connected to said conductive pliant elastomeric reference plane.

Claim 16

Dependent Claim 98 words

Apparatus as set forth in claim 9 wherein said means defining said test probe comprises a two-point probe and said capacitance measuring means comprises a four point capacitance meter having first and second high- and low-potential sensory terminals respectively coupled to one point on said two-point probe and to said conductive pliant elastomeric backside reference plane and first and second high- and low-potential drive terminals respectively coupled to the other point on said two-point probe and to said upwardly facing conductive surface on said non-conductive board interposed between said support and said conductive pliant elastomeric backside reference plane.

Claim 17

Dependent Claim 180 words

Apparatus as set forth in claim 9 further including a non-conductive board having upwardly and downwardly facing conductive surfaces thereon and defining a through opening therein sized to receive the circuit board to be tested, said non-conductive board being disposed above and upon said conductive pliant elastomeric reference plane with said downwardly facing conductive surface in electrical contact with said conductive pliant elastomeric reference plane; means for securing said first named and last named non-conductive boards, conductive pliant elastomeric reference plane and support in a rigid sandwich-like configuration; and, wherein said means defining said test probe comprises a two-point probe and said capacitance measuring means comprises a four point capacitance meter having first and second high- and low-potential sensory terminals respectively coupled to one point on said two-point probe and to said conductive pliant elastomeric backside reference plane and first and second high- and low-potential drive terminals respectively coupled to the other point on said two-point probe and to said upwardly facing conductive surface on said non-conductive board interposed between said support and said conductive pliant elastomeric backside reference plane.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1989-04-14	1989-10-14	1990-04-15	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1993-04-14	1993-10-14	1994-04-15	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1997-04-14	1997-10-14	1998-04-15	$7700.00	Window Closed / Lapsed

Capacitive circuit board testing system and method using a conductive pliant elastomeric reference plane

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