| 摘要 |
A chromatically corrected deflecting device for particle-beam equipment, particularly electron-beam equipment, comprises an electric deflecting field and a magnetic deflecting field which are simultaneously employed for the deflection of a beam. The two deflecting fields are normal to each other and are oriented relative to each other in such a manner that the beam deflections due to the associated deflecting fields occur in one and the same plane, i.e. in the plane containing the undeflected beam. The electric deflection is at the same time directed in opposition to the magnetic deflection. The ratio of the magnitude of the electric deflection angle to the magnitude of the magnetic deflection angle remains at a constant value which is independent of the resulting total deflection angle and is chosen such that the chromatic aberrations affecting the deflections due to the individual fields exactly compensate each other with reference to their effect on the beam position in the working plane, the constant value of the ratio of the magnitudes of the deflection angles being uniquely determinable as a function of at least one of the distance of the deflecting fields from the working plane, and the energy and rest mass of the particles to be deflected by particle-optical means.
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