Method and apparatus for adapting a standard flying prober system for reliable testing of printed circuit assemblies
OwnerRobert J. Russellinventor
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Abstract
A method and apparatus allows adapting a standard flying prober system to manually or automatically determine the likelihood of error free probability of test point targets on Printed Circuit Assemblies (PCA's) which may have significant planarity irregularities. The method and apparatus provides a corrective function allowing error free probing of test target points on PCA's having planarity irregularities which otherwise make them impractical to test. The method and apparatus involves utilizing the camera system typically provided with a flying prober system and an auxiliary sighting system each having different optical axis angles, the use of which allows determination of height values.
Claims20
A method of predicting prior to performing any testing the misprobing of test target points in flying prober testing of PCA's which contain a number of pre-established points or test target points defined by x and y coordinates, the system including at least one angled probe and, a camera system mounted to a support with an optical axis set perpendicularly to the ideal plane of the PCA for pretest determination of proper x and y coordinate positioning of test target points and other points during testing using a screen area containing a cross hair or similar positioning marking which is normally positioned in the center of the screen area for proper alignment of a test target point or other point on the PCA, the method including the addition of an auxiliary sighting system having an optical axis set at an angle to the ideal plane of the PCA and mounted to the same support as the perpendicularly mounted camera wherein the method comprises the following steps performed prior to any testing:
- (a) selecting one of the previously established test target points or other points and positioning the perpendicularly set camera directly above the selected test target point or other point based on the x and y coordinate data for that test target point or point;
- (b) establishing the point on the PCA indicated by the auxiliary sighting system to be directly in line with the optical axis of the auxiliary sighting system;
- and
- (c) determining the point at which said angled probe would contact the PCA in the area of the selected point based on point location data obtained during calibration to predict if the probe tip would suitably contact one or more test target points during the testing of the PCA.
Apparatus for predicting misprobing of test target points in testing of PCA's which contain a number of pre-established points defined by x and y coordinates, the flying prober system including at least one probe, a camera system mounted with a support with an optical axis set perpendicularly to the ideal plane of the PCA for pretest determination of proper x and y coordinate positioning of test target points and other points during testing using a screen area containing a cross hair or similar positioning marking which is normally positioned in the center of the screen area for proper alignment of a point on the PCA and means for selecting one of the previously established points and positioning the cross hair or similar positional marking system, the apparatus comprising:
- (a) an auxiliary sighting system having an optical axis set at an angle to the perpendicularly mounted camera;
- (b) mounting apparatus for mounting the auxiliary sighting system to the same support as the perpendicularly mounted camera;
- and
- (c) apparatus for determining the point on the PCA which is in direct line with the optical axis of the auxiliary sighting system.
A method of predicting prior to performing any testing the misprobing of test target points in flying prober testing of PCA's which contain a number of pre-established points defined by x and y coordinates, the system including at least one angled probe and, a camera system mounted to a support with an optical axis set perpendicularly to the ideal plane of the PCA for pretest determination of proper x and y coordinate positioning of test target points and other points during testing using a screen area containing a cross hair or similar positioning marking which is normally positioned in the center of the screen area for proper alignment of a point on the PCA, the method comprising the following steps performed prior to any testing:
- (a) selecting one of the previously established test target points or other points and positioning the perpendicularly set camera directly above the selected test target point or other point based on the x and y coordinate data for that test target point or other point;
- (b) establishing the point on the PCA indicated by an auxiliary sighting system to be directly in line with the optical axis of the auxiliary sighting system, the optical axis being set at an angle to the optical axis of the perpendicularly mounted camera;
- and
- (c) determining the point at which said angled probe would contact the PCA in the area of the selected point based on point location data obtained during calibration to predict if the probe tip would suitably contact one or more test target points during the testing of the PCA.
Dependencies are inferred from the claim text.