Optical Pickup Transport Error Equalization for Playback Quality
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Solution Overview
Problem
In optical disk apparatuses with a single transport mechanism for multiple optical pickups, achieving minimal lens shift and maintaining high record playback quality is challenging due to errors in relative distance and accuracy, leading to performance deterioration.
Innovation Solution
The apparatus employs a transport control circuit that adjusts the transport mechanism to equalize the absolute value of maximum and minimum transport errors among optical pickups, minimizing lens shifts and optimizing their positions on the disk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single transport mechanism is used to transport multiple optical pickups, then device complexity is reduced, but transport error and lens shift increase leading to deteriorated record playback quality
Solution Approach 1:
The transport control circuit dynamically adjusts transport parameters (position, speed, acceleration) based on detected transport errors of individual optical pickups. By changing control parameters in real-time, the system compensates for manufacturing tolerances and mechanical errors, maintaining high playback quality while using a single transport mechanism.
Solution Approach 2:
The system incorporates feedback loops where transport errors of optical pickups are detected and fed back to the transport control circuit. This feedback enables continuous correction of transport deviations, allowing the single transport mechanism to achieve precision comparable to multiple independent mechanisms.
2Device complexity
If a single transport mechanism transports multiple optical pickups, then the structure is simplified, but lens shift amount increases causing off-track errors and signal quality degradation
Solution Approach 1:
The system changes operational parameters by dynamically adjusting the transport mechanism's position and movement characteristics based on real-time error detection. This parameter adaptation minimizes lens shift effects and prevents off-track errors, maintaining reliable playback quality despite the simplified single-mechanism structure.
Solution Approach 2:
The patent replaces pure mechanical precision with a hybrid system combining mechanical transport with electronic control and feedback. By substituting mechanical error correction with electronic parameter adjustment, the system achieves high reliability without requiring complex mechanical structures for each optical pickup.
3Manufacturing precision
If transport errors of optical pickups are not equalized, then maximum transport error determines playback quality, but unequal errors cause inconsistent performance across multiple pickups
Solution Approach 1:
The transport control circuit independently adjusts transport parameters for each optical pickup based on its specific error characteristics. By changing control parameters individually for each pickup, the system equalizes transport errors across all pickups, ensuring consistent playback quality without requiring overly complex control architecture.
Data Source
AI summary
A record playback apparatus of the present disclosure includes a plurality of optical pickups that records information on a recording medium or plays back information from the recording medium; a single transport mechanism that transports the plurality of optical pickups together; and a transport control circuit that drives the single transport mechanism so that, when the single transport mechanism is driven to transport the plurality of optical pickups to respective target positions on the recording medium, absolute value of a maximum value of transport errors of the plurality of optical pickups with respect to the respective target positions becomes substantially equal to absolute value of a minimum value of transport errors of the plurality of optical pickups with respect to the respective target positions.