Multi-Layer Optical Recording Medium with Metal Oxide Composition
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Solution Overview
Problem
Current optical recording media face challenges in increasing recording capacity and reducing costs while maintaining high transmission characteristics, particularly in multi-layer configurations where the number of recording layers affects light transmission and storage reliability.
Innovation Solution
The use of oxide layers comprising metals such as W, Mo, Zr, Mn, Cu, Ag, Ni, Zn, and Mg in specific atomic ratios in the recording layers, formed through reactive sputtering, to enhance transmission characteristics and recording capacity, with configurations that include dielectric layers for improved durability and light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of recording layers is increased to increase recording capacity, then the recording capacity increases, but the light transmission characteristics deteriorate due to multiple layers absorbing and scattering light
Solution Approach 1:
The patent applies parameter changes by precisely controlling the atomic ratios of metals A, B, and C in the inorganic recording layer. By optimizing the composition parameters (specifically satisfying 0.46 ≤ x1 = a/(b+0.8c) where a, b, and c are atomic ratios of metals A, B, and C respectively), the recording layer achieves both high light transmission and high recording sensitivity, resolving the contradiction between increasing layer number for capacity and maintaining transmission characteristics.
Solution Approach 2:
The patent employs composite materials by creating an inorganic recording layer composed of three different metals (A, B, and C) with specific properties. Metal A (W, Mo, or Zr) provides high melting point and structural stability, metal B (Mn) contributes to magnetic properties and light absorption characteristics, and metal C (Cu, Ag, or Ni) enhances conductivity and optical properties. This composite structure enables the layer to simultaneously achieve high light transmission and high recording capacity.
2Reliability
If inorganic recording materials are used to improve storage reliability, then the storage reliability increases, but the manufacturing cost increases compared to organic pigment materials
Solution Approach 1:
The patent reduces manufacturing cost through parameter changes by optimizing the atomic ratios of the three metals in the inorganic recording layer. By satisfying the specific relationship 0.46 ≤ x1 = a/(b+0.8c), the formulation achieves high storage reliability while using cost-effective combinations of metals, making the inorganic recording medium more competitive with organic pigment materials.
3Illumination intensity
If the transmittance of recording layers is increased to improve light transmission, then the light transmission characteristics improve, but the recording sensitivity deteriorates
Solution Approach 1:
The patent resolves this contradiction through precise parameter changes in the metal composition ratios. By controlling the atomic ratios to satisfy 0.46 ≤ x1 = a/(b+0.8c), the recording layer achieves an optimal balance where sufficient light transmission is maintained while recording sensitivity remains high, eliminating the need to compromise either parameter.
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 creation of optical recording media with excellent transmission characteristics and recording capacity, reducing costs while maintaining high reliability and sensitivity, even in multi-layer configurations.
Implementation Method 1
recording and reproduction of an information signal by using laser light
Implementation Method 2
formed through reactive sputtering
Data Source
AI summary
Provided is an optical recording medium including two or more recording layers, and a light irradiation surface that is irradiated with light for recording an information signal on the two or more recording layers. Among the two or more recording layers, at least one layer other than a layer located on the deepest side from the light irradiation surface includes an oxide of a metal A, an oxide of a metal B, and an oxide of a metal C. The metal A is at least one kind among W, Mo, and Zr, the metal B is Mn, and the metal C is at least one kind among Cu, Ag, and Ni. Ratios of the metal A, the metal B, and the metal C satisfy a relationship of 0.46≤x1 (provided that, x1=a/(b+0.8c), a representing an atomic ratio [atom %] of the metal A with respect to the sum of the metal A, the metal B, and the metal C, b representing an atomic ratio [atom %] of the metal B with respect to the sum of the metal A, the metal B, and the metal C, and c representing an atomic ratio [atom %] of the metal C with respect to the sum of the metal A, the metal B, and the metal C.