Optical Recording Medium Groove Detection and Mode Selection
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Solution Overview
Problem
Existing optical recording media face challenges in achieving good signal quality during recording and reproduction, particularly in determining whether to use in-groove or on-groove recording, which requires a trial and error approach, leading to longer start-up times.
Innovation Solution
A method that directs a laser beam at an optical recording medium with spiral or concentric circular grooves, using a split photodetector to determine whether the grooves are convex or concave, allowing for controlled tracking and selection between in-groove or on-groove recording, and an optical recording medium with distinct identification and information recording regions to facilitate this determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a trial and error approach is used to determine whether to use in-groove or on-groove recording, then the recording mode can be determined, but the start-up time becomes longer
Solution Approach 1:
The invention applies preliminary action by pre-forming grooves in the identification region before the actual recording process. These pre-formed grooves allow the reproducing apparatus to determine the groove type (convex or concave) in advance, enabling the system to select the appropriate recording mode (in-groove or on-groove) before recording begins, thus eliminating the need for trial-and-error approaches during start-up.
Solution Approach 2:
The invention segments the optical recording medium into two distinct regions: an identification region and an information recording region. The identification region contains pre-formed grooves used solely for determining the groove type and selecting the recording mode. This segmentation allows the system to perform mode determination separately from the actual information recording process, improving efficiency without compromising accuracy.
2Manufacturing precision
If the laser beam spot diameter is reduced to improve resolution, then the recording precision improves, but the signal quality deteriorates due to insufficient light reflection
Solution Approach 1:
The invention applies local quality by using different laser beam spot diameters for different regions of the optical recording medium. In the identification region, a larger spot diameter is used to ensure sufficient light reflection and high signal quality for groove type determination. In the information recording region, a smaller spot diameter is used to achieve high recording precision. This localized adaptation of beam parameters optimizes both signal quality and recording precision in their respective regions.
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
Enables recording and reproduction with good signal quality by accurately selecting the appropriate recording mode, reducing start-up time and improving the convenience of optical recording devices.
Implementation Method 1
information is recorded or reproduced with this medium by means of thermal energy produced by irradiation with a laser beam
Implementation Method 2
receiving the laser beam reflected by the information recording layer with a photodetector
Data Source
AI summary
A method for recording and reproducing information to/from with an optical recording medium, with which either in-groove recording or on-groove recording is selected according to a type of the recording medium, and information can be recorded and reproduced with good signal quality. In this method a laser beam is reflected by an information recording layer and is received by a photodetector that has been split into at least two parts by a split line parallel to the direction of the grooves. Further, the laser beam is reflected in a region in which a groove width is greater than a width between grooves, and the method determines whether the grooves on a side where the laser beam is incident are convex or concave based on a sum signal and a difference signal of photodetection signals outputted from the photodetector.