Optical Recording Medium Polymer Binder Shape Change
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Solution Overview
Problem
Conventional optical information recording media face challenges in achieving high sensitivity recording due to the requirement for high light absorption ratios, which limits the number of recording layers and recording sensitivity.
Innovation Solution
A multi-layered optical information recording medium is developed with recording layers containing a polymer binder and dye, where the polymer binder undergoes shape change upon heating, forming protrusions towards intermediate layers, allowing for high sensitivity recording with lower absorption ratios and increased storage capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the light absorption ratio of recording layers is lowered to allow the recording beam to reach deeper recording layers, then the recording beam can penetrate more layers, but the recording layer will not receive sufficient energy from the recording beam, resulting in insufficient recording sensitivity
Solution Approach 1:
The invention changes the physical state and properties of the polymer binder by controlling the glass transition temperature and using specific polymer types (polyvinyl acetate, polymethylmethacrylate, polyethylmethacrylate, polybutylmethacrylate, polyisobutylmethacrylate, polycyclohexylmethacrylate, polyacrylonitrile, polyvinyl alcohol, polyacrylic acid, or polyacrylamide) to enable shape change at lower temperatures. This allows the recording layer to form protrusions with lower absorption ratios, thereby increasing the number of recording layers while maintaining recording sensitivity.
Solution Approach 2:
The invention utilizes the phase transition of the polymer binder at its glass transition temperature. When the recording layer is irradiated with a recording beam, the polymer binder undergoes a phase change from a rigid state to a more flexible state, enabling shape change and formation of protrusions. This phase transition mechanism allows efficient energy utilization at lower absorption ratios, resolving the contradiction between penetrating depth and recording sensitivity.
2Volume of moving object
If conventional recording materials (dye or metal) are used, then recording can be achieved through decomposition or phase change, but high light absorption ratios are required which limits the number of recording layers
Solution Approach 1:
The invention uses a composite recording material consisting of a polymer binder and dye dispersed in the polymer binder. The dye absorbs the recording beam energy and converts it to thermal energy, which then causes the polymer binder to undergo shape change. This composite structure allows efficient energy transfer from the dye to the polymer binder, enabling protrusion formation with lower overall energy absorption requirements compared to conventional single-material systems.
Solution Approach 2:
The polymer binder acts as an intermediary material that mediates between the dye (which absorbs light energy) and the final recording structure (protrusions). The dye absorbs the recording beam and transfers energy to the polymer binder, which then undergoes shape change to form the recording structure. This intermediary role of the polymer binder enables efficient energy utilization and reduces the required light absorption ratio.
3Reliability
If the recording layer thickness is increased to improve recording sensitivity, then more material is available for energy absorption, but the recording beam has difficulty reaching deeper layers
Solution Approach 1:
The invention changes the thermal and mechanical parameters of the recording layer by using polymers with specific glass transition temperatures and adding plasticizers. This allows the recording layer to be thinner while still achieving sufficient shape change and protrusion formation, thereby maintaining recording sensitivity without increasing the thickness that would block deeper layers.
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 configuration enables highly sensitive recording with reduced energy requirements and lower absorption ratios, allowing for a larger number of recording layers and improved optical reading contrast, thereby enhancing storage capacity and sensitivity.
Implementation Method 1
when the dye is irradiated with a recording beam and generates heat by absorption of the recording beam
Implementation Method 2
the polymer binder undergoes a change in shape by the generated heat
Data Source
AI summary
An optical information recording medium 10 comprises a plurality of recording layers 14 and intermediate layers 15 each provided between the recording layers 14. Each of the recording layers 14 includes a polymer binder and dye dispersed in the polymer binder, and a thickness of each recording layer is equal to or greater than 50 nm. A first interface (near-side interface 18) is formed between a recording layer 14 and an intermediate layer 15 that is adjacent to the recording layer 14 on one side of the recording layer 14 in a thickness direction of the recording layer 14, and a second interface (far-side interface 19) is formed between the recording layer 14 and an intermediate layer 15 that is adjacent to the recording layer 14 on the other side of the recording layer 14 in the thickness direction of the recording layer 14. When the dye is irradiated with a recording beam and generates heat by absorption of the recording beam, the polymer binder undergoes a change in shape by the generated heat, so that at least one of the first interface and the second interface undergoes a change in shape and sticks out toward the intermediate layer 15 to form a protrusion, whereby information is recorded in the optical information recording medium 10.