MASTER DISK CUTTING DEVICE

摘要

PURPOSE:To form a uniform track groove and an address signal pit with no effect given by aging of a piezoelectric element due to the continuous impression of voltage by decreasing the cutting degree of a cutting tool to the extension of the piezoelectric element. CONSTITUTION:A cutting tool attachment surface 15 is formed so as to obtain the positive inner product between the external normal line vector of the surface 15 and the external normal line vector of the surface of a master disk. A cutting tool 8 is joined to the surface 15 via a piezoelectric element 9 and shifted in parallel in response to the extension of the element 9. Thus the cutting degree changes. The surface 12 of the master disk is cut with the prescribed depth and with no voltage impressed to an electrode 10. Thus the groove processing is started. At this stage of processing, the element 9 has no extension and therefore a groove of uniform depth is formed with no effect of aging. The element 9 is extended when the voltage is impressed to the electrode 10 with signal input. Then the tool 8 is pushed to a cutting tool feed stage 11 and shifted in parallel in the direction where it gets away from the master disk. This means a reduction of the cutting degree, and a signal pit 14 is formed on the groove bottom surface 13.