Optical Disc Drive Laser Control for Jitter Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical information reproducing apparatuses face issues with laser noise causing deterioration of reproduced information, especially during high-speed recording and reproduction, due to the high-frequency current superimposition method which can damage recorded data and fail to prevent jitter at low-speed reproduction.
Innovation Solution
An optical information reproducing apparatus that determines the parameters of the high-frequency current based on the type and reproduction speed of the information recording medium, ensuring the ratio of peak to average light intensity is within a predetermined threshold to prevent data damage and maintain suppressed jitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-frequency current is superimposed on drive current to suppress laser noise, then jitter of reproduced information is reduced, but peak light intensity increases causing damage to recorded information on recordable media
Solution Approach 1:
The patent applies dynamics by making the high-frequency current parameters (amplitude and frequency) adjustable and adaptive rather than fixed. The control unit dynamically changes these parameters based on the magnitude of the drive current to maintain the peak-to-average light intensity ratio below the threshold, allowing jitter suppression at all drive current levels without damaging recordable media
Solution Approach 2:
The patent changes the parameters of the high-frequency current (amplitude and frequency) based on the drive current magnitude. By adjusting these parameters, the system maintains the peak light intensity ratio below the threshold value while still achieving jitter suppression, effectively resolving the contradiction between noise reduction and media protection
2Reliability
If high-frequency current with large amplitude is superimposed to suppress jitter, then noise from returned light is reduced, but reproduction light quality deteriorates due to excessive peak intensity
Solution Approach 1:
The system dynamically adjusts the high-frequency current amplitude based on drive current magnitude. At low drive currents where jitter is problematic, higher amplitude is applied; at high drive currents where peak intensity could damage media or degrade light quality, the amplitude is reduced to maintain the peak-to-average ratio below the threshold
Solution Approach 2:
The patent changes the amplitude parameter of the high-frequency current according to the drive current magnitude, ensuring that noise suppression is achieved without exceeding the peak light intensity ratio threshold that would cause reproduction light quality deterioration
3Reliability
If fixed high-frequency current parameters are used for jitter suppression, then noise is reduced at high-speed reproduction, but the same parameters cause damage at low-speed reproduction
Solution Approach 1:
The patent implements dynamic parameter adjustment where the control unit changes the high-frequency current amplitude and frequency based on the detected drive current magnitude. This allows the system to optimize jitter suppression at each reproduction speed while preventing media damage through adaptive parameter control
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 deterioration of reproduction light and maintains high reliability by adjusting the high-frequency current parameters according to the specific conditions of the medium and reproduction speed, ensuring reliable data retrieval across different types and speeds.
Implementation Method 1
a semiconductor laser which generates a laser beam
Implementation Method 2
receives a reflected light from the information recoding medium and converts the information recorded on the disc 52 into the electric signal
Data Source
AI summary
A deterioration of reproduction light is occurred by a laser drive current on which a high-frequency current is superimposed. The present invention, for example, is an optical information reproducing apparatus which irradiates a laser beam to an optical disc 1 and reads an information, the optical information reproducing apparatus includes a semiconductor laser 6 which generates the laser beam, a laser drive unit 7 which supplies a drive current on which a high-frequency current are superimposed to the semiconductor laser 6, a spindle motor 2 which drives the optical disc 1 and a control unit 5 which controls the laser drive unit 7 and the spindle motor 2, and the control unit 5 determines a parameter of the high-frequency current based on magnitude of a current on which the high-frequency current is to be superimposed.