Bi Oxide Recording Layer Sputtering for Optical Media

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Solution Overview

Problem

Mn-based oxides used in optical recording media require a long time to form a film, making them disadvantageous in terms of tact time.

Innovation Solution

The use of an optical recording medium with a recording layer containing an oxide of Bi, formed by sputtering a Bi oxide target in a process gas mixture of rare gas and oxygen, with an oxygen flow rate ratio of 0.15 or more.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If Mn-based oxide is used as recording material, then cost is reduced, but film formation time increases

Engineering Contradiction:

ImprovecostVSAvoidfilm formation time

Core Design Contradiction:

Ease of manufactureVSLoss of time

Solution Approach 1:

The patent changes the material parameter from Mn-based oxide to Bi-based oxide, which fundamentally alters the film formation characteristics. Bi-based oxide enables significantly faster film formation while maintaining cost-effectiveness, directly resolving the contradiction between cost reduction and film formation time.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a disposable target material (Bi-based oxide) that can be quickly consumed during sputtering to form the recording layer. This approach prioritizes speed over durability, allowing rapid film formation without requiring expensive or long-lasting target materials, thus reducing both cost and formation time.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Productivity

If Bi oxide target is sputtered with high oxygen flow rate, then film formation time is shortened, but oxidation control becomes more difficult

Engineering Contradiction:

Improvefilm formation speedVSAvoidoxidation control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent optimizes the oxygen flow rate parameter to a specific range (0.15 or more) to achieve the desired balance. By carefully controlling this parameter, the process achieves fast film formation while maintaining sufficient oxidation control to produce the correct Bi oxide phase, resolving the contradiction between speed and precision.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs monitoring and feedback mechanisms during the sputtering process to adjust oxygen flow rate and other parameters in real-time. This feedback control ensures that the oxidation level remains within the optimal range, preventing excessive oxidation while maintaining high film formation speed.

Inventive Principle:

Principle #23Feedback

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 significantly shortens the film formation time of the recording layer, thereby reducing the overall production time and cost, while maintaining high signal quality.

Implementation Method 1

forming a recording layer by sputtering a target while introducing a process gas, wherein the target contains an oxide of Bi

Methodology Applied

Scientific EffectSputtering: Sputtering

Data Source

PatentUS12272393B2Optical recording medium, manufacturing method thereof, recording material for optical recording medium, and sputtering target for optical recording medium

Publication Date: 2025.04.08 SONY GROUP CORP

AI summary

Provided is an optical recording medium capable of shortening tact time. The optical recording medium includes at least one recording layer. The recording layer contains an oxide of Bi.