| 摘要 |
PURPOSE:To prevent any positional shift of the projected image of a light source which might be caused due to an elevation of the light source so as to improve the accuracy of exposure by using a face plate having a concave-lens-like shape and specifying the curvature radius of the concave surface. CONSTITUTION:An emission tube 2 consists of an emitter part 2a and an outer tube 2b. The opening of a shielding plate 2c attached around the outer tube 2b works as an exposure light source. The shape of the above opening is almost symmetrical relative to the rotation axis (l) of a rotary base. Cooling water 11 is filled around the emission tube 2. The axis of the face plate 3a corresponds to the longitudinal direction of the emission tube 2. The face plate 3a has a flat columnar concave-lens-like shape having a concave surface on the side of a panel. The apparent elevations (PA) and (PB) of the light source seen from the longitudinal direction and the vertical direction of the emission tube 2 is adjusted to be almost equal. Owing to the above constitution, the roundness of the projected image of the exposure light source is improved, thereby enabling the quality of a fluorescent film to be increased. |
