Optical Pick-Up Head Location Detection via Sector Signals
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Solution Overview
Problem
Existing DVD-RAM disk reading technologies face inefficiencies and errors during track-jump operations due to prolonged PLL phase locking times or failure, especially when the optical pick-up head slips to erroneous addresses far from the target zone, leading to degraded disk drive performance.
Innovation Solution
A system comprising a signal generator, counter, and processing unit that detects the location of the optical pick-up head by generating sector determined signals and period determined signals, allowing accurate counting and calculation of the head's position, enabling precise adjustment of PLL frequency and spindle speed for improved tracking and following operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pre-determined PLL frequency and spindle speed are used according to target zone, then data reading efficiency is improved, but tracking accuracy deteriorates when optical pick-up head is at erroneous address far from target zone
Solution Approach 1:
The system performs preliminary detection of the optical pick-up head's actual location using sector determined signals and counter before initiating the track jump operation. This preliminary action allows the system to identify erroneous addresses and correct them in advance, preventing tracking errors while maintaining efficient pre-determined PLL frequency and spindle speed settings for data reading.
2Measurement precision
If optical pick-up head is moved back to servo-on area for repositioning, then tracking accuracy is restored, but time consumption increases significantly
Solution Approach 1:
The invention replaces the mechanical repositioning method (moving optical pick-up head back to servo-on area) with an electronic signal processing method. By using sector determined signals, IDGATE signals, and counter to detect and calculate the optical pick-up head's location, the system can electronically identify and correct positioning errors without physical repositioning, significantly reducing time consumption while maintaining tracking accuracy.
3Device complexity
If stepping motor and step index are used to detect location, then location detection is simplified, but reliability deteriorates when stepping motor does not operate as desired
Solution Approach 1:
The system introduces sector determined signals and IDGATE signals as intermediary elements between the optical pick-up head and the location detection mechanism. These signals are generated from the disk structure itself (sectors and tracks) and provide a reliable reference for location detection that does not depend on stepping motor operation, thereby improving reliability while maintaining detection simplicity.
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 enhances data reading efficiency and accuracy by quickly determining the optical pick-up head's location, reducing errors and time-consuming repositioning, thereby improving disk drive performance.
Implementation Method 1
the optical pick-up head emitting light to the optical disk and detected the reflected light from the optical disk
Data Source
AI summary
Disclosed is a system for detecting a location of an optical pick-up head on an optical disk, and the optical disk comprises a plurality of sectors and the optical pick-up head emitting light to the optical disk and detected the reflected light from the optical disk. The system comprises: a signal generator, a counter, and a processing unit. The signal generator is coupled to the optical pick-up head for receiving a detecting signal from the optical pick-up head to generate a sector determined signal. The counter is coupled to the signal generator for receiving the sector determined signal and a period determined signal for counting a number according to the sector determined signal and the period determined signal; and a processing unit for receiving the number and calculating the location of the optical pick-up head accordingly.