Holographic Storage Medium Layer Discrimination via Reflection Layers
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Solution Overview
Problem
Current holographic data storage technologies face challenges in commercially viable data storage due to the difficulty in adjusting optical systems finely for volume holography and in distinguishing between multiple data layers in micro-holography methods.
Innovation Solution
A holographic data storage medium with a substrate, holographic recording layer, and cover layer, featuring a data recording region with interference fringes in different data layers and a layer discrimination region using reflection layers, such as cholesteric liquid crystal materials, to differentiate between data layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If volume holography method is used to record vast amount of data at the same time, then data storage capacity is improved, but optical system adjustment complexity increases making it difficult to commercialize
Solution Approach 1:
The invention divides the storage medium into multiple distinct data layers separated by positioning layers. Each data layer can be independently accessed and recorded, segmenting the complex volume holography process into manageable layers. This segmentation reduces the complexity of optical system adjustment while maintaining high data storage capacity through multi-layer recording.
2Manufacturing precision
If micro-holography method is used to form fine interference fringes on a plane, then data recording precision is improved, but ability to distinguish between multiple data layers deteriorates
Solution Approach 1:
The invention introduces positioning layers as intermediary elements between data layers. These positioning layers contain positioning marks that serve as mediators for identifying and distinguishing between multiple data layers. The positioning layers do not interfere with the fine interference fringe recording in data layers while providing a mechanism for layer discrimination, thus resolving the contradiction between recording precision and layer distinguishability.
3Quantity of substance
If multiple data layers are formed in depthwise direction of volume holographic recording layer, then data storage density is improved, but ability to discriminate between data layers deteriorates
Solution Approach 1:
Positioning layers are introduced as intermediary elements between data layers. These positioning layers contain positioning marks that enable discrimination between multiple data layers formed in the depthwise direction. The positioning layers provide a structural framework that maintains high data storage density through multi-layering while enabling easy identification and access to specific layers through the positioning marks.
4Difficulty of detecting and measuring
If positioning layers are alternated with information recording layers, then data layer discrimination is improved, but device structure complexity increases
Solution Approach 1:
The positioning layers serve multiple functions: they provide structural separation between data layers, contain positioning marks for layer discrimination, and maintain the overall integrity of the multi-layer structure. This multi-functionality reduces the need for additional specialized components, thereby limiting the increase in device structure complexity while achieving effective data layer discrimination.
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 effective discrimination and recording/reproducing of multiple data layers, enhancing data storage density and commercial viability by using reflection layers to store layer number data and specific data in a transmissive or reflective-type medium.
Implementation Method 1
a reference beam and a signal beam with different paths interfere with each other to form an interference fringe that causes chemical or physical changes to a photosensitive storage medium
Implementation Method 2
storing data in the shape of optical interference fringes in inorganic crystals or polymer materials that are sensitive to light
Implementation Method 3
the reference beam similar to a beam used for recording the data is irradiated to the interference pattern recorded in the photosensitive storage medium. As a result, diffraction occurs due to the interference pattern, so that the signal beam is restored to reproduce the data
Implementation Method 4
the reflection layer in the layer discrimination region is formed of a cholesteric liquid crystal (CLC) material
Data Source
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AI summary
Provided are a holographic data storage medium and an apparatus and method for recording/reproducing holographic data using the same. The holographic data storage medium includes: a substrate; a holographic recording layer disposed on the substrate; and a cover layer covering the holographic recording layer. The holographic recording layer includes: a data recording region including a plurality of data layers to which data is recorded, the data recording region in which interference fringes due to first and second beams are formed in different data layers in a depthwise direction; and a layer discrimination region for providing discrimination between the data layers.