| 摘要 |
An x-ray imaging apparatus receives an image-carrying x-ray beam (12) on a flat amorphous silicon imaging panel (20) with a light detector unit (40) disposed behind. The imaging panel is of a multilayered structure having sequentially a light-blocking layer (26) which is opaque to visible light but transmissive to x-rays, a converting layer of a phosphorescent material (98) for converting x-rays incident thereon into visible light, and a twodimensional array of photosensitive elements (30) of an amorphous semiconductor material such as amorphous silicon, adapted to undergo a detectable change in electrical characteristic in response to impingement of light. The light detector unit (40) may be a simple light detector for receiving the light emitted from the converting layer and passed through regions between neighboring pairs of the array of photosensitive elements (30). Since the energy of light thus detected is directly proportional to the total light energy emitted from the converting layer, the output signal from such a light detector unit can be conveniently used for the exposure control of the imaging panel.
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