| 摘要 |
PURPOSE:To reduce a device in cost and size by allowing the 2nd inspecting means to perform inspection regarding the state of a defect as to only a disk surface which is not decided on to have no defect. CONSTITUTION:When disk surfaces of the disk to be inspected begin to be read, a signal of a CH 1 is selected and outputted to a channel switching circuit 2. Consequently, signals of CHs 1-(n) are supplied to inspecting circuits 3 and 4 to make decisions 3 and 4 on whether or not the disk surfaces have a defect. When this decision making is finished and signals S1 and S2 indicating the decision results are supplied from the circuits 3 and 4, the signals of the CHs 1-(n) are outputted selectively to the circuit 2. Consequently, a precise decision on whether or not a disk surface which is not decided clearly on to have no defect has a defect is detected 3 successively and the size and position of a defect of a disk surface which is decided on to have the defect are detected 3, so that the detection results is displayed on a display means.
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