Matsushita Electric Industrial Co., Ltd.

Toshio Satoh

Takashi Ishida

Kenzo Ishibashi

Shunji O'Hara

Shunji Ohara

Tomio Yoshida

Yoshinobu Nakata

In an optical recording and reproducing apparatus which forms at least first and second light spots on a track of an optical recording medium to record, reproduce or erase information, a movable range of the second light spot is limited to less than one half of a track pitch, normal to the track, from the track to prevent tracks other than a target track from being miserased, misrecorded or misreproduced. When a deviation of the second light spot from the target track exceeds a predetermined amount, light emission of the second light spot is stopped to prevent a track other than the target track from being miserased, misrecorded or misreproduced. When the deviation of the second light spot from the target track exceeds the predetermined amount, the second light spot is returned to a neutral position to prevent a track other than the target track from being miserased, misrecorded or misreproduced.

Optical recording and reproducing apparatus having a plurality of light

In an optical recording and reproducing apparatus which forms at least first and second light spots on a track of an optical recording medium to record, reproduce or erase information, a movable range of the second light spot is limited to less than one half of a track pitch, normal to the track, from the track to prevent tracks other than a target gtrack from being miserased, misrecorded or misreproduced. When a deviation of the second light spot from the target track exceeds a predetermined amount, light emission of the second light spot is stopped to prevent a track other than the target track from being miserased, misrecorded, or misreproduced. When the deviation of the second light spot from the target track exceeds the predetermined amount, the second light spot is returned to a neutral position to prevent a track other than the target track from being miserased, misrecorded, or misreproduced.

Tracking system for an optical recording/reproducing apparatus having a

In an optical recording and playback disc apparatus, two light beams (l, m) are focused by a common focusing lens (108) onto an information track (51) of the optical recording disc, and the focused light means (l, m) form two light spots (L, M), the position thereof being controlled by a first tracking servo loop (115, 116 and 117), and furthermore, one (M) of the light spots is independently controlled from the other light spot (L) by a second tracking servo loop (120, 121 and 122).

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Hirakata, Japan

Toshio Satoh