Patent ID: 7132843
Filing Date: 2006-11-07
Classification: G01R,H05K

Abstract:
1. A method of positioning a test head, suitable for electrical measurements, by means of a computation unit on a printed circuit board, comprising: providing at least one first and at least one second adjusting mark on the printed circuit board, wherein the at least one first and at least one second adjusting marks each comprise at least two parts, comprising a frame, which is bounded by an outer edge and an inner edge, enclosing a region, and each further comprising at least one enclosed mark being arranged in the region, and wherein each of the frames and the corresponding at least one enclosed mark are at a defined measurement potential; initially positioning the test head within an area which is bounded by the outer edge of the first adjusting mark; re-positioning the test head within the area via a search algorithm in the computation unit in order to receive potential values which are associated with the corresponding frame of the first adjusting mark and the corresponding region of the first adjusting mark, wherein data that is fransrnitted from the test head to the computation unit is evaluated, and the computation unit calculates the position and length of the inner edge of the first adjusting mark, which is associated with the frame of the first adjusting mark, and the position of the corresponding enclosed mark of the first adjusting mark, such that the test head is moved to the calculated position of the enclosed mark of the first adjusting mark, wherein the test head detects the enclosed mart of the first adjusting mark by means of potential measurements, and determined first coordinates of the enclosed mark of the first adjusting mark are stored in the computation unit; repeating the above recited steps of initially positioning the test head within an area and re-positioning the test head via a search algorithm at the second adjusting mark to obtain determined second coordinates of the corresponding enclosed mark of the second adjusting mark, and subsequently determining positioning of the test head with respect to the printed circuit board according to the determined first and second coordinates of the enclosed marks of the first and second adjusting marks.