this mode generally a pulsed radiation source is employed and the programmable patterning device is updated as required after each movement of the substrate table wt or in between successive radiation pulses during a scan this mode of operation can be readily applied to maskless lithography that utilizes programmable patterning device such as a programmable mirror array of a type as referred to above combinations and or variations on the above described modes of use or entirely different modes of use may also be employed fig2 a depicts an embodiment of a shutter system ss that may be used with the lithographic apparatus shown in fig1 the shutter system ss comprises four shutters s sometimes referred to as blades the shutters s are disposed about a common center point c and each shutter s is movable towards and away from the center point c the shutters s are made from a material which is opaque to the radiation beam pb of fig1 the shutters s are generally in the same plane however this is not essential for example one or more of the shutters s may be located at any appropriate position in the lithographic apparatus for example one or more of the shutters s may be located after the patterning device ma or located in the illuminator il of fig1 referring back to fig2 a in use the shutters s are moved to an appropriate position to mask out specific areas of the patterning device ma of fig1 from the radiation beam pb this masking is undertaken to ensure that the radiation beam pb is of a specific cross sectional area or shape when.