Contactless test method and system for testing printed circuit boards
First Claim
1. A method for testing an unpopulated circuit board including electrically conductive paths, parts, and surfaces whose electrical and physical continuity and conformance to a known standard is to be verified, the method comprising providing a signal applying conductor;
- providing an array of non-contact sensors;
placing an unpopulated circuit board under test between the signal applying conductor and the array such that the board under test is free from direct electrical contact with the signal applying conductor and with the array;
powering the signal applying conductor by an AC electrical signal independent of geometric layout of the conductive material on the board under test to generate an original electromagnetic near field which is transmitted from the signal applying conductor to the array for detection thereby;
using the said array of non-contact sensors, without direct electrical contact with the board under test, to detect a pattern of perturbation of the original electromagnetic near field of the signal applying conductor caused by the board under test, said pattern of perturbation therefore defining a test pattern representative of the circuit board under test;
making a comparison of the said test pattern with a known pattern; and
determining from the said comparison whether the board under test is in conformance to the known standard.
2 Assignments
0 Petitions
Accused Products
Abstract
This application describes a method of testing for manufacturing faults and quality of unpopulated or inactive populated electronic printed circuit boards (PCB). This method can be used to develop a new contactless test system (CTS). An electromagnetic field is generated by an energizing plate connected to an AC signal. When a board under test (BUT) is placed within the electromagnetic field, perturbation of the original field by conducting elements on the BUT is solely a function of the geometrical layout of the conducting elements on the BUT. Therefore, measurement of the perturbed electromagnetic field produces a characteristic pattern for the BUT. Such a pattern can then be compared to a known pattern for the same type of board to determine whether the BUT is faulty (shorts or opens) or not faulty. The most distinctive feature of this method is that testing PCBs by this method requires no electrical contact with the BUT due to the use of the energizing plate.
100 Citations
14 Claims
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1. A method for testing an unpopulated circuit board including electrically conductive paths, parts, and surfaces whose electrical and physical continuity and conformance to a known standard is to be verified, the method comprising providing a signal applying conductor;
- providing an array of non-contact sensors;
placing an unpopulated circuit board under test between the signal applying conductor and the array such that the board under test is free from direct electrical contact with the signal applying conductor and with the array;
powering the signal applying conductor by an AC electrical signal independent of geometric layout of the conductive material on the board under test to generate an original electromagnetic near field which is transmitted from the signal applying conductor to the array for detection thereby;
using the said array of non-contact sensors, without direct electrical contact with the board under test, to detect a pattern of perturbation of the original electromagnetic near field of the signal applying conductor caused by the board under test, said pattern of perturbation therefore defining a test pattern representative of the circuit board under test;
making a comparison of the said test pattern with a known pattern; and
determining from the said comparison whether the board under test is in conformance to the known standard. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- providing an array of non-contact sensors;
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8. A method for testing an inactive populated circuit board including electrically conductive paths, parts, and surfaces whose electrical and physical continuity and conformance to a known standard is to be verified, the method comprising providing a signal applying conductor;
- providing an array of non-contact sensors;
placing an inactive populated circuit board under test between the signal applying conductor and the arrayarray such that the board under test is free from direct electrical contact with the signal applying conductor and with the array;
powering the signal applying conductor by an AC electrical signal independent of geometric layout of the conductive material on the board under test to generate an original electromagnetic near field which is transmitted from the signal applying conductor to the array for detection thereby;
using the said array of non-contact sensors, without direct electrical contact with the board under test, to detect a pattern of perturbation of the original electromagnetic near field of the signal applying conductor caused by the board under test, said pattern of perturbation therefore defining a test pattern representative of the circuit board under test;
making a comparison of the said test pattern with a known pattern; and
determining from the said comparison whether the board under test is in conformance to the known standard. - View Dependent Claims (9, 10, 11, 12, 13, 14)
- providing an array of non-contact sensors;
Specification