by Dennis Crouch

Most patents involve two or more joint inventors who all claim to have contributed significantly to the invention.  Conception of the invention is typically seen as the critical legal determinant of invention and some courts have written that each joint inventor must have contributed substantially to the conception of the invention.*  Conception is typically referred to as a mental act. The MPEP, for example, includes a statement in all-caps that "CONCEPTION MUST BE DONE IN THE MIND OF THE INVENTOR."  MPEP 2138.04(I).  The basic rule is that the inventor must have a "definite and permanent idea of the complete and operable invention."