| 摘要 |
PURPOSE:To obtain an optical recording disk which has little external disturbance to a tracking error signal and can count the number of sectional grooves precisely at the time of retrieval by connecting bits in a format area with each other by fine grooves. CONSTITUTION:A space between a bit a1 and a bit a2 in a format area of an optical recording disk is connected by a groove b1 having width thinner than those of the bits a1 and the a2. A space between the bit a2 and a groove 2 is connected with a fine groove b2. With the constitution, when light beams travel along a guide track, diffraction is generated by the groove b1 between the bits a1 and a2, a tracking error signal is produced, and a large external disturbance will not occur. When the light beams travel between the bits a1 and a2 in an arrow X direction, and pass through between them at the time of retrieval, diffraction is generated by the groove b1, and a signal crossing the groove is produced, thereby making accurate retrieval possible. A width W1 of the bit part and a width W3 of the groove have almost the same value, and a width w2 of the connecting groove is preferably >=1/2 of the width w1 and w3. |
