| 摘要 |
PURPOSE:To execute a stable recording and the reproducing operation of all beams by using beams radiated from at least two semiconductor lasers out of an array-like light source for an optical head for separating plural reflected beams in space and independently reproducing respective separated beams for detecting a spot position detecting error on a recording medium. CONSTITUTION:Plural beams 20d-20f from a recording medium 27 are converged by a lens 28 and separated in space by a light separating element 13 and the center beam 20e is made incident upon a detector 32 to obtain a pit signal. The beams 20d, 20f, for detecting both servo and pit signals are made incident upon detecting systems 15, 16 and an error signal is inputted to an arithmetic circuit 14. When both signals are averaged, an actuator 25 is driven and focus servo is driven so that the medium is positioned on the intermediate position of a converged beam spot, so that a defocused variable is reduced and a fine spot can be obtained. Consequently, the offset variable of the focus and track servos for all the plural beams can be reduced and stable recording and reproducing operation can be attained. |
