In a pattern definition device for use in a particle-beam exposure apparatus a plurality of blanking openings (910) are arranged within a pattern definition field (bf) composed of a plurality of staggered lines (bl) of blanking openings, each provided with a deflection means controllable by a blanking signal (911); for the lines of blanking openings, according to a partition of the blanking openings of a line into several groups (g4,g5,g6), the deflection means of the blanking openings of each group are fed a common group blanking signal (911), and the group blanking signal of each group of a line is fed to the blanking means and connected to the respective blanking openings independently of the group blanking signals of the other groups of the same line.