| 摘要 |
PURPOSE:To inspect change in recessed and projecting parts of a coated object and that in color and then eliminate scattering by mounting a differential interference lens with a specific magnification in front of a CCD camera for capturing reflection light fro an object to be inspected. CONSTITUTION:For observing a surface defect of an object 7 to be inspected such as a magnetic drum and an optical disk a CCD camera 1 is mounted so that the distance to the surface of the object 7 to be inspected is maintained to be constant. A differential interference lens 2 with a magnification of 5-400 or a bright visual field lens 3 is mounted as needed. It is desirable that a mercury-xenon lamp 5 should be mounted to maintain the brightness of the object 7 to be inspected to be constant. Also, it is desirable that a dichroic mirror 4 should be mounted in front of the camera 1 to examine the change in color. A signal from the camera 1 is guided to an oscilloscope 6, thus judging presence or absence of defect. At this time, the width of a reference value is determined previously and those above or below the value are determined to be defective. |
