Optical Disc Spherical Aberration Correction Mechanism
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Solution Overview
Problem
Optical disc devices face inefficiencies in spherical aberration correction, requiring lengthy adjustment processing whenever the data recording layer changes, leading to user wait times due to temperature-dependent lens characteristics and individual differences in optical disc media.
Innovation Solution
An optical disc device with a spherical aberration correction mechanism that concurrently measures evaluation values while changing the aberration amount, allowing for rapid calculation of an optimum setting value for the SA parameter, thereby shortening the adjustment processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adjustment processing of the SA parameter is executed every time the data recording layer changes, then reading accuracy is maintained, but user wait time increases
Solution Approach 1:
The system performs preliminary measurement of evaluation values at multiple SA parameter settings during the focus adjustment process, before the actual data reading begins. This allows the optimum SA parameter to be pre-determined for the current data recording layer, eliminating the need for time-consuming adjustment processing when switching between layers.
Solution Approach 2:
The system automatically determines the optimum SA parameter by measuring evaluation values at different settings and selecting the best one, without requiring manual user intervention. The control unit autonomously performs the measurement and selection process, reducing user wait time while maintaining reading accuracy.
2Reliability
If the optimum SA parameter is determined for each data recording layer, then reading accuracy improves, but adjustment processing time increases
Solution Approach 1:
The system continuously measures evaluation values while the collimator lens is moving to different positions corresponding to different SA parameter settings. This concurrent measurement process eliminates idle time and allows multiple measurements to be performed in parallel during the lens movement, significantly reducing the total adjustment processing time.
Solution Approach 2:
The system performs periodic measurements of evaluation values at different SA parameter settings during the focus adjustment process. By conducting these measurements in periodic intervals while the lens moves, the system efficiently gathers sufficient data to determine the optimum parameter without requiring continuous stopping and measurement, thereby reducing overall processing time.
3Reliability
If multiple measurements of evaluation values are performed sequentially, then reading accuracy is optimized, but processing time increases
Solution Approach 1:
The system merges multiple measurement operations with the focus adjustment process by conducting evaluation value measurements concurrently with the collimator lens movement. This combination allows multiple measurements to be performed in parallel rather than sequentially, optimizing reading accuracy while maintaining high processing speed.
Solution Approach 2:
The system transitions from sequential time-based measurement to spatial-concurrent measurement by measuring evaluation values at different SA parameter settings simultaneously during lens movement. This dimensional change from single-time-point measurement to multi-time-point concurrent measurement enables parallel processing, significantly improving productivity while maintaining accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces the time required for spherical aberration correction, enabling faster data recording layer changes and improving reading accuracy by measuring evaluation values during the movement of the collimator lens, thus enhancing operational efficiency.
Implementation Method 1
an objective lens that focuses light on the optical disc medium
Implementation Method 2
receives reflected light obtained by reflection of the light focused by the objective lens by the optical disc medium
Implementation Method 3
a spherical aberration correction mechanism that changes an amount of spherical aberration of the objective lens
Data Source
AI summary
An optical disc device that reads information recorded in an optical disc medium includes an objective lens that focuses light on the optical disc medium, a spherical aberration correction mechanism that changes an amount of spherical aberration of the objective lens according to a setting value of a predetermined parameter, and an evaluation value measurement section that measures an evaluation value indicating the accuracy of reading of information from the optical disc medium. The optical disc device further includes a control section that executes adjustment processing in which the control section carries out plural times of measurement of the evaluation value by the evaluation value measurement section concurrently with changing the amount of spherical aberration of the objective lens by the spherical aberration correction mechanism and calculates an optimum setting value of the parameter based on plural evaluation values obtained by the plural times of measurement.