Gravity-Assisted Nanostructure Transfer Using Temperature-Controlled Stamper
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Solution Overview
Problem
Existing methods for manufacturing molded products with fine structures, such as hot embossing and UV optical nanoimprint, face challenges like stamper mold breakage, high pressurization requirements, and increased production costs, limiting their applicability and efficiency, especially for nano-scaled features.
Innovation Solution
A method involving a temperature-controlled stamper mold with a fine concavo-convex pattern, where a thermoplastic molten polymer layer is formed and held in contact without pressurization, allowing the fine structure to be transferred under gravity, then cooled and solidified, and finally released, preventing stamper mold breakage and enabling high-productivity, large-area, homogeneous molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hot embossing method is used to manufacture molded product with fine structure, then productivity is improved and various thermoplastic polymer substrates can be fabricated, but high pressure is needed and polymer fluidity is insufficient in filling stage of high aspect ratio fine structure
Solution Approach 1:
The patent changes the temperature parameter to above the polymer's melting point, transforming the polymer into a molten state with significantly improved fluidity. This allows the polymer to flow into high aspect ratio fine structures without requiring high pressure, thus resolving the contradiction between productivity and pressure requirements
Solution Approach 2:
The patent utilizes the dynamic fluidity of molten polymer at temperatures above melting point, allowing the material to adapt and flow into complex fine structures. This dynamic state enables complete filling of high aspect ratio features that would be impossible in the solid or softened state
2Temperature
If hot embossing method heats polymer to melting temperature, then polymer fluidity exceedingly increases, but polymer substrate only undergoes deformation of extending in plane direction and is not filled into deep groove portion of fine structure
Solution Approach 1:
The patent introduces a stamper mold with fine structures as an intermediary tool that guides and constrains the molten polymer flow. The stamper mold's fine structures act as a template that directs the polymer into deep groove portions, preventing unwanted plane direction extension while ensuring complete filling of the desired fine structure geometry
Solution Approach 2:
The patent performs preliminary heating of the polymer to melting temperature before contact with the stamper mold, ensuring the polymer reaches an optimal fluidity state. This preliminary preparation allows the polymer to be ready for immediate filling into fine structures upon contact, controlling shape deformation from the outset
3Manufacturing precision
If UV optical nanoimprint method is used, then processing can be performed at room temperature with low transcribed pressure and highly accurate pattern can be molded, but photo-curable polymer exhibits small shrinkage at curing and has adhesive properties making it difficult to release imprinted film from stamper mold
Solution Approach 1:
The patent creates a replica mold that copies the fine structures from the original stamper mold. This replica serves as the actual molding tool, allowing the imprinted film to be released from the replica rather than the original stamper mold, thus preventing fine structure breakage while maintaining pattern accuracy
Solution Approach 2:
The patent uses a replica mold as a buffer or cushioning layer between the imprinted film and the original stamper mold. This intermediary replica absorbs the release stress, protecting the delicate fine structures of the original stamper mold from breakage during the release process
4Manufacturing precision
If pressurization is applied to transfer fine structure of stamper mold, then fine structure can be transferred, but stamper mold is broken
Solution Approach 1:
The patent creates a replica of the stamper mold that serves as the actual transfer tool. The replica absorbs the mechanical stress during pressing and release operations, allowing fine structure transfer without compromising the integrity of the original stamper mold
Solution Approach 2:
The patent treats the replica mold as a disposable or sacrificial element that can withstand repeated pressing and release cycles. The replica is designed to be replaced when worn, protecting the expensive original stamper mold from damage while maintaining fine structure transfer quality
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 enables the economical manufacturing of molded products with fine structures up to 1 µm width and high aspect ratios without pressurization, reducing stamper mold damage and internal strain, while allowing for broad material choices and low production costs, suitable for various molding techniques.
Implementation Method 1
in a temperature-controlled stamper mold having a fine structure comprising a concavo-convex pattern having a width of 10 nm to 1 μm, a thermoplastic molten polymer layer to be in contact with the fine structure is formed
Implementation Method 2
the thermoplastic molten polymer layer is cooled and solidified, whereby the fine structure of the stamper mold is transcribed to the thermoplastic molten polymer layer without pressurization by a pressurization apparatus
Implementation Method 3
it is appressed to the stamper mold without pressurization, so that the adhesive force is larger than the thermal stress of a molten polymer in the thermoplastic molten polymer layer
Data Source
Figure 1(a)~3
Figure 4~5(b)
Figure 6~7
AI summary
The present invention is widely applicable to an injection molding method, an injection compression molding method, a blow molding method, a film sheet molding method using a roller and a thermoplastic molten polymer, and the like. An object of the invention is to provide a method for manufacturing a molded product with fine structure, which can transfer-mold a fine structure using any of various thermoplastic molten polymers without particularly requiring a pressurizing apparatus and can afford a nano-scaled fine pattern having a high economical efficiency, a large area, and homogeneous properties. The invention includes steps of, in a temperature-controlled stamper mold provided with a fine structure including a concavo-convex pattern having a width of 10 nm to 1 µm, forming a thermoplastic molten polymer layer to be in contact with the fine structure of the stamper mold having been kept at a predetermined temperature and holding the thermoplastic molten polymer layer for a predetermined time so as to transfer the fine structure of the stamper mold to the thermoplastic molten polymer layer under gravity.