| 摘要 |
1,237,809. X-ray examination of articles. INTERNATIONAL BUSINESS MACHINES CORP. Aug.29, 1969 [Sept. 13, 1968], No. 43106/69. Heading G1M. [Also in Division H5] A method of examining during manufacture an article such as a laminated printed circuit comprises positioning an X-ray sensitive film 9, Fig. 1, between an X-ray opaque brass template 3 and a steel base 1 by means of locating pins 2, and briefly exposing the film to X-rays 10 through registration holes in the masking plate 3. This is intended to provide registration marks on the film. The film remains unmoved on the base 1 but is then covered by a glass plate instead of the brass plate 3, Fig. 2, and is also covered by exactly registered or positioned but as far unlaminated circuit panels 7 to be inspected for spacing and location of detail features which are then subjected to X-rays 14. The photographed image of the panels 7 is unaffected by the first masked exposure which provided registration marks only, and the film is now developed. The circuit panels are now laminated together and a new film mounted alone under brass plate 3 and given a first or registration marking exposure. The plate 3 is then replaced by the now laminated together panels 8 and the film exposed to X-rays 15, Fig. 3 and then removed. The two films are developed into transparencies and then superimposed in registration on a known light table, Figs. 4-8 (not shown) and examined under a magnifying glass to see if the details of the laminated together or formed circuit laminations as shown on the second transparency are correctly spaced one to another as compared with the originally registered or exactly positioned but unformed laminations shown on the first transparency. In a modification, Fig. 9, the plate 3a is a "picture frame" only bordering the article but permitting X-ray photography of the article and provision of the registration marks to be accomplished in a single step. |
