Double-Sided Optical Disc Orientation Detection Using Asymmetric Laser Reflection

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Solution Overview

Problem

Double-sided optical discs without label layers pose a challenge in distinguishing the front from the rear side, leading to difficulties in determining if they are placed reversely within an optical disc drive, which can result in inefficient data access due to incorrect rotation direction.

Innovation Solution

The optical disc drive employs two control modules with optical pickup heads to emit laser beams to specific areas on the disc, generating alternate brightness and darkness changes to determine the correct orientation, allowing for immediate adjustment of the spindle motor's rotation direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a double-sided optical disc without label layer is used, then data storage capacity is improved, but the ability to distinguish front from rear side deteriorates

Engineering Contradiction:

Improvedata storage capacityVSAvoiddifficulty to distinguish front from rear side

Core Design Contradiction:

Quantity of substanceVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies local quality by creating asymmetric features at specific locations on the disc. The first specified area on the first side contains recorded information while the second specified area on the second side does not, creating local differences that enable orientation detection without affecting the overall double-sided data storage capacity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements asymmetry by making the first specified area and second specified area different in terms of recorded information. This asymmetric configuration allows the optical pickup head to detect the disc orientation by comparing the presence or absence of recorded information in these specific areas, solving the problem of distinguishing front from rear side.

Inventive Principle:

Principle #4Asymmetry

2Speed

If the optical disc is placed reversely, then data access speed deteriorates, but the device structure remains simple

Engineering Contradiction:

Improvedata access speedVSAvoiddevice structure complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-recording identification information in the first specified area before the disc is loaded into the drive. This allows the optical pickup head to detect the correct orientation immediately upon loading, enabling the system to adjust the spindle motor rotation direction in advance, thereby ensuring optimal data access speed without adding complex detection mechanisms.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If an optical pickup head emits laser beam to detect disc orientation, then orientation detection accuracy is improved, but energy consumption increases

Engineering Contradiction:

Improveorientation detection accuracyVSAvoidenergy consumption of optical pickup head

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by having the optical pickup head detect only specific specified areas on the disc rather than scanning the entire surface. The laser beam is targeted at the first specified area on the first side or the second specified area on the second side, enabling orientation detection with minimal energy expenditure while maintaining high detection accuracy.

Inventive Principle:

Principle #16Partial or excessive action

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 method enables quick confirmation of the disc's orientation and adjusts the rotation direction accordingly, enhancing data access efficiency by preventing misalignment and ensuring correct data layer access.

Implementation Method 1

the first optical pickup head of the first control module emits a laser beam to a specified area of the double-sided optical disc and receives a reflected laser beam from the specified area

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS10115426B1Optical disc and method for judging whether optical disc is placed reversely

Publication Date: 2018.10.30 LITE ON TECH CORP

AI summary

A method is provided for judging whether a double-sided optical disc is placed reversely. Firstly, the disc is loaded. Then, a first optical pickup head emits a first laser beam to a first specified area of the disc and receives a first reflected laser beam. A second optical pickup head emits a second laser beam to a second specified area of the disc and receives a second reflected laser beam. If the first reflected laser beam generates an alternate brightness and darkness change and the second reflected laser beam does not generate the alternate brightness and darkness change, the disc is not placed reversely. If the first reflected laser beam does not generate the alternate brightness and darkness change and the second reflected laser beam generates the alternate brightness and darkness change, the disc is placed reversely.