Optical Disc Device Spherical Aberration Correction
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Solution Overview
Problem
Optical disc devices face challenges in dynamically adjusting control parameters, such as the spherical aberration correction parameter, during operation due to changes in temperature, leading to potential reading errors and increased adjustment time.
Innovation Solution
The optical disc device implements a method to correct the spherical aberration parameter by using a combination of first and second correction processing techniques, where the second correction processing is executed frequently to maintain accuracy and the first correction processing is executed less frequently to recalibrate when significant temperature changes occur, allowing for quick and accurate adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical disc device performs adjustment processing to correct control parameters during operation, then reading accuracy is maintained, but the information reading operation is suspended and adjustment time increases
Solution Approach 1:
The patent implements dynamic correction by continuously monitoring temperature changes and automatically adjusting the spherical aberration correction parameter in real-time during operation. The system transitions from static pre-set correction values to dynamic adaptive correction based on actual operating conditions, allowing the collimator lens position to be adjusted on-the-fly without suspending reading operations.
Solution Approach 2:
The patent employs feedback control by measuring the actual temperature of the objective lens during operation and using this information to determine the appropriate spherical aberration correction amount. The system continuously monitors temperature and adjusts the collimator lens position accordingly, creating a closed-loop control system that maintains reading accuracy without requiring operation suspension.
2Measurement precision
If the optical disc device frequently adjusts the spherical aberration correction parameter, then reading accuracy is maintained under temperature changes, but device complexity increases
Solution Approach 1:
The patent changes the physical parameter being controlled from mechanical lens positioning to electrical drive signal adjustment. By controlling the drive current of the collimator lens motor through DAC (digital-to-analog converter) and PWM (pulse width modulation) techniques, the system adjusts the spherical aberration correction parameter electronically, reducing mechanical complexity while maintaining precision.
Solution Approach 2:
The patent replaces complex mechanical adjustment mechanisms with electronic control systems. Instead of using mechanical linkages and physical adjustment components, the system uses electronic signals to control the collimator lens position via motor drive circuits, simplifying the overall device structure while enabling frequent adjustments.
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 enables the optical disc device to maintain high reading accuracy and reduce adjustment time by dynamically updating the spherical aberration parameter, ensuring optimal performance even with temperature-induced changes in lens characteristics.
Implementation Method 1
An optical pickup which irradiates the optical disc medium with light to detect reflected light from the optical disc medium
Implementation Method 2
there is provided a collimator lens in order to correct the spherical aberration of the objective lens used for focusing light onto the optical disc medium
Data Source
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AI summary
Provided is an optical disc device capable of correcting a value of a control parameter during an operation of reading information from an optical disc medium. The optical disc device for reading the information recorded on the optical disc medium under an operation condition corresponding to a value set with respect to a predetermined control parameter corrects the value of the predetermined control parameter by repeatedly executing, while an operation of reading the information from the optical disc medium is being performed, processing of: acquiring, with respect to two values of the predetermined control parameter, evaluation values indicating accuracy of the reading of the information from the optical disc medium, respectively; and updating the value of the predetermined control parameter based on the two acquired evaluation values.