Patent GB-663714-A (GB)
Abstract: 663,714. Radiographic apparatus producing relief effects. RELIEPHOGRAPHIE SOC. POUR L'EXPLOITATION DES PROCEDES DE PHOTOGRAPHIE EN RELIEF M. BONNET. Nov. 6, 1945 [June 12, 1944], No. 29579/45. Class 98 (i). The apparatus comprises an X-ray tube, a support for the object to be radiographed, a fluorescent screen, and a photographic camera having a refringent lenticular screen located in front of the photographic surface, both the lenticular screen and photographic surface being pivotally mounted in the camera, and is characterized by means ensuring that the X-ray tube, fluorescent screen and the camera make rotational movements about the object as centre such that the fluorescent screen, the lenticular screen and the light-sensitive surface always remain parallel to one another. The extent of rotation of the lenticular screen and the associated photographic surface is preferably made equal to the aperture angle of the lenticular screen elements, viz. the angle defined by the ratio of the working diameter to the focal length. In an alternative form of apparatus the X-ray tube remains stationary while the object support and the lenticular screen and its associated photographic surface rotate about axes parallel to that of the object support, the fluorescent screen optionally pivoting about a further parallel axis. The lenticular screen may have either cylindrical or spherical elements or may comprise two sets of parallel cylindrical elements crossed at 90 degrees. The screen with spherical or crossed sets of cylindrical elements may be mounted so that after each view-taking, which yields a series of punctiform images, an unexposed area on the same photographic surface is disposed in position for a further exposure by tilting the lenticular screen and photographic surface about an axis perpendicular to the axis about which they pivot during taking. This pivoting movement during taking may be replaced by a relative sliding movement between the photographic surface and the lenticular screen in synchronism with the relative movement of the object and the photographic surface. As shown in Fig. 3, the tube A and the camera 16 remain fixed during exposure whilst the object carried on the horizontal table 3, fluorescent screen 10, and carrier 18 for the plate and lenticular screen 181 are continuously rotated through the aperture angle of the lenticular elements, and are maintained parallel to one another by parallel motion linkages 21, 11, 20, 12. Means for adjusting the distance between the object table 3 and its pivotal axis (which determines the medial plane of the radiograph) comprises at each end of the table a screw-threaded member 361 supported by lugs 362 on the table 3 working in an internally threaded nut 36 in a member carried by the shaft 2 which is guided in slideways 6, 7 also carried by the table. In a modification (Fig. 1, not shown), the arms 12 are adjustable in length by means of sleeve-pieces and are slidable through sleeves pivoted to the cross-member 20. The construction shown in Fig. 3 has the additional features that the lenticular screen 181 has part-spherical elements and the screen and plate are adjustable by the member 33 about the shaft 32 in a direction perpendicular to the shaft 19. In this way the area impressed behind each lenticule is punctiform instead of lineal so that several rows of point images representing separate exposures may be obtained on the same plate. Fig. 2 shows apparatus wherein the object remains stationary on the frame 101 whilst the tube, fluorescent screen and camera, all carried by a rod 26 pivoted on the frame 101, (the camera being also mounted on rollers carried by tracks 23, 25), are caused to rotate through an arc of a circle, equal to the aperture angle of the lenticular elements centred on the object whilst the frame 18 and the screen 10 are maintained parallel to themselves and to the frame 101 by parallel motion linkages such as shown at 30, 31, for the screen 10. Instead of the pivotal movements of the lenticular screen relative to the axis of the apparatus, the elements of the parallax panoramagram images may be recorded by maintaining the lenticular screen and photographic surface perpendicular to the axis of the lens 17 and ensuring a sliding movement between the lenticular screen and the light-sensitive plate of an amount not greater than the width of one screen element. Specifications 615,635 and 661,951 are referred to.