Patent Number: 051134250
Section: summary

BACKGROUND OF THE INVENTION This invention relates generally to X-ray imaging apparatus and more particularly to an industrial X-ray inspection system capable of providing both film and high resolution fluoroscopic images of objects under inspection. Industrial X-ray inspection systems are generally well known and are used for the non-destructive examination of objects such as castings, electronic components and assemblies as well as biological samples. Such apparatus include cabinets comprised of lead lined steel structures including a generally vertical tower assembly having an X-ray tube located at the top thereof During an inspection procedure, a piece of X-ray film is normally placed on a shelf in the cabinet at the bottom of the tower and the object of interest is placed on top of the film. Such industrial X-ray systems also typically include means to adjust the voltage and exposure time to achieve optimum image contrast of the film image. The object is then exposed to X-rays which pass through the object to produce a shadowgraph on the X-ray film which becomes visible to the eye when developed. Such apparatus is similar in many respects to that utilized for medical procedures. As in the case of medical X-ray examination systems, X-ray inspection systems used for industrial applications also utilize systems which provide fluoroscopic or "real time" imaging. These systems also employ X-ray tubes; however, instead of recording the X-ray image on film, the X-ray image is converted to a video image which is viewed via closed circuit television apparatus. In some such systems, a videcon tube converts the X-ray image directly into a video image which is displayed. Vidicon sensitive X-ray cameras, however, are expensive and short lived. In others, the X-ray image is converted to a visible image by a cesium iodide image intensifier for video viewing. Such apparatus is large and very expensive. One known type of image intensifier which has become extremely useful includes a thin coating of radioluminescent phosphor which is coupled to the input of a microchannel plate type image intensifier whose output is fed to a phosphor for generating a visible image which can thereafter be viewed. This type of apparatus is smaller in size and less costly than the above mentioned types. SUMMARY It is an object of the present invention, therefore, to provide an improvement in X-ray imaging apparatus. It is another object of the invention to provide an improvement in X-ray inspection apparatus. It is a further object of the invention to provide a high resolution industrial X-ray inspection system suitable for inspecting electronic components including circuit boards therefor. And still yet another object of the invention is to provide an improvement in an industrial X-ray inspection system which is capable of providing both film images as well as fluoroscopic images of electronic components and assemblies therefor. And still another object of the invention is to provide an improved X-ray cabinet for an industrial X-ray inspection system which is capable of easily being retrofitted to include a real time or fluoroscopic capability along with a pre-existing X-ray film capability. Yet a further object of the invention is to provide an X-ray inspection system structure for both film and real time displays having inherently lower cost than any currently available. Briefly, the foregoing and other objects of the invention are achieved by a high resolution X-ray inspection system particularly adapted for electronic circuit components comprised of an X-ray cabinet including an X-ray tube which is located in a vertical tower and where the object and film are placed on a slidable support member such as a shelf or drawer located inside the lower portion of the cabinet, with the shelf or drawer being slidable outwardly therefrom The support member has provision for a fluoroscopic imaging device which can be fitted thereto upon demand or it can be mounted in the bottom of the cabinet apart from the support member. The output of the fluoroscopic imaging device is optically coupled to a closed circuit TV camera located in the bottom of the housing beneath the slidable shelf. The fluoroscopic imaging device is comprised of a thinly coated radioluminescent phosphor plate optically coupled to the input of an image intensifier including a microchannel plate multiplier. The fluoroscopic TV image generated is viewed on a monitor located, for example, adjacent the X-ray cabinet.