Patent ID: 6992493

Claim:
An apparatus for detecting positional displacement of a board having a surface formed with a conductive pattern, relative to a direction orthogonal to a transfer direction thereof, said board, said apparatus comprising: at least two pattern-edge sensing means disposed, respectively, at predetermined arrival positions which are spaced apart from each other at a given distance and to be aligned with the leading edge of said conductive pattern located downstream relative to said transfer direction, and adapted to be capacitively coupled with said conductive pattern in a non-contact manner; signal supply means for supplying an AC signal from a given portion of said conductive pattern other than said leading edge to said leading edge; and displacement determination means for detecting the difference between respective timings when said AC signal supplied from said signal supply means is sensed by said pattern-edge sensing means, to determine the positional displacement of said board transferred to said predetermined arrival positions, wherein said signal supply means is operable to supply said AC signal at least at the time when said leading edge of said conductive pattern arrives at said predetermined arrival positions, and said displacement determination means is operable to determine the level of inclination of said board in accordance with the level of the difference between said sense signals.