摘要 |
In the manufacturing process of a screen (6), for use in a color display tube (1), a photosensitive process step, referred to as the exposure process, is used for applying the black matrix pattern and the phosphor layers to the display window (3) to form the screen (6). The robustness of this exposure process is dependent on, amongst others, the shape of the microscopic light distribution on the display window (3). It appears that in color display tubes (1) with an increased deflection angle, or in tubes with a real flat outer surface, the exposure process becomes more and more critical. According to the invention, this problem can be overcome by adding a bleaching dye to the photosensitive material used for the exposure process. This bleaching dye's action in the center of the microscopic light distribution is stronger than in the peripheral portions. As a result the slopes of the microscopic light distribution become steeper, leading to an increase of the contrast in the exposure process which thus becomes much more robust.
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