Patent ID: 7157720

Claim:
A charged particle device comprising a charged particle source configured to direct charged particles in the direction of a specimen under examination and an imaging device configured to convert charged particles to an image representing said specimen, wherein: said imaging device comprises a detector defining a pixel array; said detector is configured to generate electric charges for individual pixels of said pixel array such that said electric charges collectively define said image; said imaging device is configured such that a portion of said pixel array can be transitioned between a partially masked state and a substantially unmasked state; said partially masked state defines a set of masked readout pixels and a set of unmasked imaging pixels; said imaging device is programmed to operate in a frame transfer imaging mode when said pixel array is in said partially masked state and in a full frame mode when said pixel array is in said substantially unmasked state; said frame transfer imaging mode is configured such that an image captured by said set of unmasked imaging pixels is transferred to said set of masked readout pixels, said transferred image is subsequently transferred from said set of masked readout pixels to storage outside of said pixel array as a subsequent image is captured by said set of unmasked imaging pixels, and said subsequently captured image is transferred to said set of masked readout pixels after said initial image is transferred from said set of masked readout pixels to said outside storage; and said full frame mode is configured such that an image captured by said pixel array in said substantially unmasked state is transferred to storage outside of said pixel array as incoming charged particles are blocked from reaching said detector.