초록 ▼

An optical drive system includes an objective lens subassembly for directing light from a light source toward an information storage medium. An amount of the directed lighted light is returned from the storage medium. An objective lens is disposed in the objective lens subassembly. A first servomoto

An optical drive system includes an objective lens subassembly for directing light from a light source toward an information storage medium. An amount of the directed lighted light is returned from the storage medium. An objective lens is disposed in the objective lens subassembly. A first servomotor moves, during focus capture, the objective lens to a first position, away from the first position toward the storage medium being read while looking for a maximum Quad Sum signal, and back away from the storage medium. An electronic control circuit is connected to the first servomotor. A servo error detector is coupled to the electronic control circuit and disposed in a path of light returning from the information storage medium. The servo error detector is implemented to determine when total light returned from the information storage medium exceeds a predetermined value, to search for a first zero crossing, corresponding to when the Quad Sum signal exceeds a predetermined amplitude, and to indicate to the electronic control circuit to direct close of focus when the Quad Sum signal exceeds the predetermined amplitude.

대표청구항 ▼

[ What is claimed is:] [1.] An optical drive system, comprising:an objective lens subassembly for directing light from a light source toward an information storage medium, an amount of said light being returned therefrom;an objective lens disposed in said objective lens subassembly;at least one quad

[ What is claimed is:] [1.] An optical drive system, comprising:an objective lens subassembly for directing light from a light source toward an information storage medium, an amount of said light being returned therefrom;an objective lens disposed in said objective lens subassembly;at least one quad detector for detecting light returned from the storage medium;processing circuitry connected to said at least one quad detector to produce a Quad Sum signal related to the light detected by the quad detector;a first servomotor for moving said objective lens subassembly to effect focus capture, said first servomotor moving said objective lens to a first position, then away from said first position toward said storage medium while the medium is being read and said processing circuitry searches for a maximum Quad Sum signal, said first servomotor also moving said lens back away from said storage medium;first electronic means for controlling said first servomotor; andservo error detecting means including said at least one quad detector, said servo error detecting means being coupled to said first electronic means and implemented for determining when total light returned from said information storage medium exceeds a predetermined measured value, for searching for a first zero crossing, for determining when said Quad Sum signal exceeds a predetermined amplitude, and for indicating to said first electronic means to direct close of focus when said Quad Sum signal exceeds said predetermined amplitude.