| 摘要 |
PURPOSE:To eliminate the complicating of the master disk making of an optical disk and the reducing of a recording density by separating a track signal into a signal for a high frequency area and a signal for a low frequency are and detecting it. CONSTITUTION:A reflecting light by an optical disk 10 is made incident through an objective lens 22, an 1/4 wavelength plate 20 and a prism 18 onto a polarizing beam splitter 16, reflected in the downward direction and made incident on a light receiving element 30. The light receiving element 30 is divided to A-D in respective direct and parallel directions to a guide groove and the voltages of (a)-(d) are outputted. By adders 34 and 36 and a subtracter 38, (a+b)-(c-d) is prepared and a track signal TH for a high frequency are is obtained. For the sum of voltages (a) and (c) of light receiving part A and C facing in a slanting direction to the guide groove, a track signal TL for a low frequency area is obtained by an adder 32, a sample holding circuit 50b and a track dislocation detection 50a. Thus, the complicating of the master disk making of an optical disk and the reducing of a recording density can be eliminated.
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