Optical Disk Drive Spherical Aberration Control for Multi-Format Recognition
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Solution Overview
Problem
Current optical disk drives face challenges in accurately recognizing and handling multiple types of optical disks, including Blu-ray discs (BDs), due to variations in physical structures, track pitches, and storage layer depths, leading to difficulties in focusing and tracking control across different disk types.
Innovation Solution
An optical disk drive equipped with a spherical aberration correcting section and a control system that adjusts the light beam's spherical aberration states to generate distinct signal waveforms, allowing for accurate recognition of disk types by analyzing changes in focus error signals and amplitude, enabling compatibility with various optical disk formats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single optical system is used to handle multiple types of optical disks, then the device complexity is reduced, but the measurement precision of disk type recognition deteriorates
Solution Approach 1:
The patent changes the spherical aberration parameter of the light beam by adjusting the spherical aberration correcting section to recognize different disk types. By setting the spherical aberration to different states (first state and second state), the system generates distinct signal waveforms for different disk types, enabling accurate recognition without requiring separate optical systems for each disk format.
2Adaptability or versatility
If the spherical aberration correcting section adjusts the light beam settings for different disk types, then the adaptability improves, but the device complexity increases
Solution Approach 1:
The system uses feedback from the detected signal waveforms to automatically determine the disk type and adjust the spherical aberration correcting section accordingly. The control section monitors the difference between signal waveforms generated at different spherical aberration states and automatically selects the appropriate correction state, eliminating the need for manual configuration and reducing control complexity.
3Manufacturing precision
If the light beam is optimized for one specific disk type, then the manufacturing precision of the optical system can be maximized, but the adaptability to other disk types deteriorates
Solution Approach 1:
The patent makes the spherical aberration correcting section dynamically adjustable to adapt to different disk types. Instead of fixing the optical system for one disk type, the system can change the spherical aberration state dynamically based on the detected disk type, allowing a single optimized optical system to handle multiple formats effectively.
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
The solution enables the optical disk drive to accurately recognize and handle multiple types of optical disks, including BDs, by minimizing spherical aberration and optimizing light beam settings, thus ensuring proper focus and tracking control across different disk types.
Implementation Method 1
data can be read out from a rotating optical disk by irradiating the disk with a relatively weak light beam with a constant intensity, and detecting the light that has been modulated by, and reflected from, the optical disk
Implementation Method 2
at least one optical system including at least one light source for radiating a light beam and a lens for converging the light beam onto the optical disk
Implementation Method 3
a spherical aberration correcting section that is able to change the spherical aberration states of the light beam; and a control section for controlling the operations of the motor, the optical system and the spherical aberration correcting section
Implementation Method 4
detecting the light that has been modulated by, and reflected from, the optical disk
Implementation Method 5
a photodetector for detecting the light beam that has been reflected from the optical disk
Data Source
AI summary
The optical disk drive of the present invention can read data from multiple types of optical disks and includes: a motor for spinning a given optical disk; at least one light source for radiating light beams with multiple different wavelengths; at least one lens for converging each light beam onto the disk; a spherical aberration correcting section that can change the spherical aberration states of the beam; and a control section for controlling the operations of the motor, light source, lens and spherical aberration correcting section. The control section includes a disk type recognizing section that irradiates the disk with a light beam using the light source and the lens, thereby recognizing the type of the disk. The recognizing section performs the recognition by reference to first and second signal waveforms that have been generated based on the light beams reflected from the optical disk when the spherical aberration correcting section sets the spherical aberration states of the light beam to first and second states, respectively.