| 摘要 |
<p>The invention concerns an image reader (10) for a device designed to scan with laser beams a circular image plate (12) which has image elements (40) produced by irradiation with X-rays at a radial distance R from the centre of the plate. The reader has a fixture (13) on which the plate (12) is detachably mounted and which is driven by an adjustable-speed electric motor (11). The reader also has an image-element scanning unit (15; 15) which can be displaced radially by a drive (14; 18) at a pre-selected speed across the plate (12) and includes a laser-light supply (42) and an electro-optical signal-transmission device with an optical image-element scanning device (30a) and a photoelectric multiplier (36). In addition, the reader has a signal-processing device. The aim of the invention is to improve a reader of this kind so that, when the plate is scanned by the laser beam to record the image stored on the plate, the amount of light produced is maximized. In addition, the invention aims to produce a compact reader which is thus easier to use. To achieve this, it is proposed that the image-element scanning unit (15; 115) is moved over the image plate to scan each image element (40) at the same tangential speed. The laser-light supply (42) preferably has two laser sources (43a, 43b) the light from which passes through an optical filter (46) and is subsequently focused by a convergent lens (44). In addition, the drive shaft (18) of the electric motor (11) is preferably connected through gearing (23) to a spindle (26) by means of which the image-element scanning unit (15) is driven to execute translational motion radial to the image plate (12).</p> |
