1. An electron lens in which electron beams are focused by an electromagnetic field.
2. An electromagnet designed to produce a suitably shaped magnetic field for the focusing and deflection of electrons or other charged particles in electron optical instruments.
3. An electron lens consisting of a homogeneous axial electric field and a magnetic field, used in high-quality image tubes for high Modulation Transfer Function (MTF, a measurement of monitor sharpness) and small geometrical distortion requirements.