X-ray laminographic application of lens-coupled CMOS detector for PCB inspection

A lens-coupled CMOS detector has been tested for the application in X-ray laminography, which is a tomographic technique recently popular in the nondestructive inspection of printed circuit boards (PCBs). The lens-coupled CMOS detector is extremely cost-effective because of the simple configuration and the well-known CMOS technology. For the feasibility test, we have acquired X-ray images at various imaging conditions and analyzed them with respect to the system requirement. From the test results, although the projected image is reasonably acceptable to the normal nondestructive testing, it was concluded that the lens-coupling method is not appropriate to the laminography due to lowlight-collection efficiency. In this study, construction of the detector and its specification are described. Experimental results are reported with the discussion of the lens-coupling efficiency.