Multilayer Disc Recording Power Adjustment for Signal Quality
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Solution Overview
Problem
In multilayer information recording media, such as dual-layer DVDs, the recording power optimization for one layer can be disrupted by errors in lamination or pasting between layers, leading to inefficient use of recording areas and compromised signal quality due to relative shifts in radial positions.
Innovation Solution
An information recording apparatus and method that adjusts the recording power based on the overlap or non-overlap of recorded and unrecorded areas between layers, using specific laser powers (44 mW or 46 mW) to maintain optimal reproduction quality by displacing the edges of the recording area in the second layer, thereby minimizing waste and optimizing the recording area usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the recording power is optimized for the L1 layer when the L0 layer is in a recorded state, then good signal quality is obtained in areas where laser light penetrates the recorded L0 layer, but poor signal quality occurs in areas where laser light penetrates the unrecorded L0 layer
Solution Approach 1:
The recording power is dynamically adjusted based on the recording state of the L0 layer. The system determines whether the laser light penetrates a recorded or unrecorded L0 layer and applies different optimized recording powers (44.5mW for recorded state, 46mW for unrecorded state) to maintain appropriate asymmetry values and signal quality in all recording areas of the L1 layer
2Reliability
If the radial position of the L1 layer is shifted to satisfy the recording order, then the recording order is satisfied, but the recording area is wasted
Solution Approach 1:
Instead of physically shifting the radial position of the L1 layer recording area, the system changes the parameter of recording power dynamically. By detecting whether the laser light penetrates a recorded or unrecorded L0 layer and adjusting the recording power accordingly, the system maintains appropriate recording conditions without wasting recording area, thus resolving the contradiction between satisfying recording order and maximizing recording area utilization
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 minimizes the waste of recording areas in the second layer, ensuring efficient use and maintaining high reproduction quality by dynamically adjusting recording parameters based on the overlap or non-overlap of areas between the first and second layers.
Implementation Method 1
an optical pickup, irradiates the information recording medium with laser light
Implementation Method 2
the laser light for recording is focused or condensed on a recording layer
Implementation Method 3
the L0 layer in the recorded state has a different light transmittance from that of the unrecorded L0 layer
Data Source
AI summary
An information recording apparatus (300) is provided with: a first recording device (302 etc.) for recording the first information into a first area of the first layer; a second recording device (302 etc.) for recording the second information into a predetermined area of the second layer; and a controlling device (305) for controlling the second recording device to record the second information by the laser light, while displacing an edge indicating an innermost or outermost circumference of the predetermined area in which a penetrated area penetrated by the laser light is included in the first area, in a direction to approach an edge of the predetermined area in which the penetrated area is not included in the first area, only by a predetermined length corresponding to a tolerance of a change amount indicating a change in the reproduction quality.