JPS6480173A - Deflection linearity coil - Google Patents

Abstract

PURPOSE:To easily obtain the deflection characteristic having a sufficiently excellent symmetry by providing a coil composed of a winding, a core and a nonmagnetic spacer with variable thickness inserted in a magnetic path formed by the core and a permanent magnet applying the bias magnetic field to the coil. CONSTITUTION:A spacer 10e having various thickness using a nonmagnetic substance such as plastic is inserted selectively between cores 10c, 10d. That is, various thickness of spacers 10e are prepared, whose thickness varies at an interval of nearly 0.1mm stepwise, and the spacer with the optimum thickness is selected in realizing the symmetry of the deflection characteristic on the way of assembling. Thus, the current versus inductance (L) characteristic in the linearity coil is deviated to the left/right attended with the change in the bias magnetic field depending on the position relation between the coil 10 and the permanent magnet 11 and shifted vertically attended with the charge in the thickness of the spacer 10e. That is, the current versus inductance characteristic is increased/decreased in response to the thickness of the spacer 10e.