Optical Disk Drive Orientation Detection and Collision Prevention
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Solution Overview
Problem
Optical disk drives struggle to accurately distinguish between properly and improperly loaded optical disks, particularly when different types like BDs and CDs are loaded upside down, leading to potential collisions and data access issues due to similar information storage layer depths and label layer interference.
Innovation Solution
An optical disk drive with a control section that includes a right/wrong side determining section, which uses electrical signals from an optical pickup to assess whether the disk is loaded correctly by adjusting the focal point and detecting focus or tracking errors, and by recognizing features like burst cutting areas, to prevent collisions and ensure proper data access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the optical pickup irradiates the optical disk to detect the information storage layer, then data access is enabled, but collision may occur when the disk is loaded upside down due to similar storage layer depths
Solution Approach 1:
The patent applies preliminary action by performing orientation detection before data access operations. The control section executes a focus search to detect the label layer position and determines disk orientation (correct or upside-down) before allowing the optical pickup to access data, thereby preventing collision damage from premature irradiation on incorrectly loaded disks
Solution Approach 2:
The patent uses the label layer as an intermediary indicator to determine disk orientation. By detecting the label layer's position through focus search and using it as a reference, the system indirectly determines whether the disk is correctly loaded without directly attempting data access that could cause collision
2Measurement precision
If the focus search is performed to detect the information storage layer, then data reading is enabled, but the label layer may interfere with accurate detection
Solution Approach 1:
The patent segments the detection process into two distinct phases: first detecting the label layer position through focus search, then using that information to determine orientation and guide subsequent storage layer access. This segmentation allows the system to handle label layer interference by treating it as a separate detection target that provides orientation information rather than obstructing storage layer detection
Solution Approach 2:
The patent implements feedback by using the label layer detection results to control subsequent storage layer access. The control section receives feedback from the focus search about label layer position, determines disk orientation based on this feedback, and then adjusts the focus search parameters or prevents storage layer access accordingly, creating a closed-loop control system
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
The solution effectively prevents collisions and ensures accurate data access by determining the correct orientation of optical disks, particularly for BDs and CDs, thereby enhancing the reliability and safety of optical disk drives handling multiple types of optical media.
Implementation Method 1
irradiating the disk with a relatively weak light beam with a constant intensity, and detecting the light that has been modulated by, and reflected from, the optical disk
Implementation Method 2
a 'focus control' and a 'tracking control' are required. The 'focus control' means controlling the position of an objective lens perpendicularly to the information storage layer
Data Source
AI summary
An optical disk drive according to the present invention has the ability to read data from multiple types of optical disks, each of which includes at least one information storage layer. The drive includes: a driving mechanism 120, which is loaded with a selected one of the optical disks of the multiple types and which rotates the optical disk 102; an optical pickup 30 for irradiating the optical disk 102, which has been loaded into the driving mechanism 120, with a converged light beam, thereby generating an electrical signal based on light that has been reflected from the optical disk 102; and a control section (ODC 50) for controlling operations of the driving mechanism 120 and the optical pickup 30. The control section 50 includes a right/wrong side determining section for determining, by reference to the electrical signal generated by the optical pickup 30, whether or not the optical disk 102 has been loaded into the driving mechanism 120 with the other surface opposed to the optical pickup 30.