Holographic Disc Guide Grooves for Beam Positioning
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Solution Overview
Problem
Holographic storage systems face challenges with vibration and wobble of the disc during recording and readout due to larger displacement compared to micro-hologram size, affecting the accuracy of data storage and retrieval.
Innovation Solution
An optical disc structure with embedded guide grooves and coatings that reflect a tracking beam while transmitting read or record beams, allowing for real-time tracking and focusing, and a method of manufacturing this disc with a substrate layer, optically-enabled material, and multiple data layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If holographic storage systems use larger disc formats to increase storage capacity, then storage capacity is improved, but vibration and wobble displacement increases causing recording and readout problems
Solution Approach 1:
The patent divides the disc surface into multiple concentric circular tracks, each track containing multiple micro-holograms. This segmentation allows the system to focus on smaller, more stable regions for data storage, reducing the impact of overall disc vibration and wobble on recording and readout accuracy while maintaining large storage capacity across the entire disc surface.
Solution Approach 2:
The patent implements different functional zones on the disc surface: data regions containing micro-holograms and guide groove regions with enhanced reflective properties. The guide grooves provide localized tracking references that help maintain beam positioning accuracy despite disc vibration, creating local quality variations that improve overall system reliability.
2Manufacturing precision
If micro-hologram size is reduced to increase data density, then storage capacity is improved, but the disc becomes more sensitive to vibration and wobble
Solution Approach 1:
The patent arranges micro-holograms in a three-dimensional configuration within the disc volume, utilizing multiple layers at different depths. This dimensional approach allows high data density without proportionally reducing the effective target size for beam focusing, as the system can access data at multiple depth planes, reducing sensitivity to lateral vibration and wobble.
Solution Approach 2:
The guide grooves act as intermediary reference structures between the beam positioning system and the micro-holograms. These grooves provide stable tracking references that mediate the effect of disc vibration on beam positioning, allowing the system to maintain accurate beam alignment with small micro-holograms despite vibration and wobble.
3Productivity
If the disc rotates at higher speeds to increase data access rate, then productivity is improved, but vibration and wobble increase affecting beam positioning
Solution Approach 1:
The patent employs a feedback mechanism where the beam positioning system continuously monitors the position of the beam relative to the guide grooves and adjusts the beam direction accordingly. This real-time feedback compensates for vibration and wobble effects, allowing high rotation speeds to be maintained while preserving beam positioning accuracy for data access.
Solution Approach 2:
The guide grooves are pre-formed on the disc surface before data recording, providing stable reference structures that are unaffected by rotation speed. The beam positioning system uses these pre-existing grooves to establish accurate positioning references before data access operations begin, enabling high-speed rotation without sacrificing positioning precision.
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
Enables stable real-time recording and readout of micro-holograms by controlling beam positioning through tracking beam analysis, enhancing data storage capacity and accuracy in holographic data storage systems.
Implementation Method 1
a first coating disposed on the guide grooves and configured to reflect a tracking beam
Implementation Method 2
to transmit a read or record beam
Implementation Method 3
holograms, which are images of three dimensional interference patterns created by the intersection of two beams of light in a photosensitive storage medium
Implementation Method 4
photosensitive storage medium resulting in a chemical reaction which, for example, changes or modulates the refractive index of the medium
Implementation Method 5
The data is then retrieved by using a read beam to diffract off the micro-hologram to reconstruct the recording beam
Data Source
AI summary
An optical disc for micro-holographic data storage, including: optically-enabled material configured to store holographic data; guide grooves; a first coating disposed on the guide grooves and configured to reflect a tracking beam and to transmit a read or record beam; and a second coating disposed to cover the guide grooves and disposed on the first coating.