| 摘要 |
In an image converter tube, the brightness contrast of the output picture is reduced by light which is internally reflected at the surfaces of the window through which the image is viewed. The contrast can be improved by making the window partially light-absorbing, at the expense of a reduction in the overall optical gain. This gain varies considerably from tube to tube. By adding an external filter on the output window, the transmission of the filter can be chosen for each tube to provide the minimum acceptable gain and thus the maximum obtainable contrast.
|
