| 摘要 |
PURPOSE:To prevent an end flicker phenomenon from happening in and around a filament in an effective manner, by setting up a magnetic field generator in position proximate to the filament of a discharge tube, while providing a magnetic field crossing with an electric field of the discharge tube and prescribing the tube average magnetic flux density of the magnetic field. CONSTITUTION:A flicker preventing effect has a certain close relationship to the magnetic flux density of an impressed magnetic field but, on the other hand, a discharge tube comes hard to start glowing in proportion to an increase of magnetic flux density due to a rise in starting voltage. A reference line L means the lowest value of the flicker preventing effect; the higher in ambient temperature the larger in magnetic flux density being required for flicker prevention. In addition, at an ambient temperature of 10 deg.C-30 deg.C, it is recommended that the tube average magnetic flux density be 500 gauss or so for the flicker preventing effect. From this viepoint, such a magnetic field generator that satisfies an equation of Y >=a X+b is installed. The figure Y in this equation is tube average magnetic flux density (gauss), X is tube current density (mA/mm.<2>), a is about 290-355 and b is about -45--170, respectively. |
