Reflective Optical Film Thickness Gradient Co-Extrusion
Solution Overview
Problem
Existing methods for manufacturing reflective optical films lack effective control over thickness gradients, leading to unbalanced fluid pressure and velocity during the co-extrusion process, which can result in damage and inefficiencies in the production of multilayer reflective sheets.
Innovation Solution
A method involving a feedblock multiplier with thickness-gradient variation, where materials are fed through a segmenting section with a bevel or curved cross-section to create multiple layers with gradually decreasing thicknesses from the outermost sides to the middle, balancing fluid velocity and pressure, and incorporating birefringence material layers to optimize optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform thickness is used in multilayer reflective sheets, then manufacturing process is simple, but fluid pressure and velocity become unbalanced during co-extrusion
Solution Approach 1:
The patent applies local quality by implementing variable thickness in different regions of the multilayer reflective sheet. The thickness gradient is designed to be symmetric with respect to the central axis, where the thickness at the center is different from the thickness at the edges. This local variation in thickness allows different regions to have different optical properties while maintaining overall symmetry, thereby balancing fluid pressure and velocity during co-extrusion without compromising manufacturing feasibility.
2Reliability
If thickness gradient variation is introduced, then fluid dynamics are balanced, but manufacturing complexity increases
Solution Approach 1:
The patent employs asymmetry in a controlled manner by introducing a thickness gradient that is symmetric about the central axis but asymmetric in terms of varying thickness from center to edges. This specific type of asymmetry allows the thickness to change gradually across the sheet while maintaining symmetry that balances fluid dynamics. The asymmetric thickness distribution reduces shearing forces and balances fluid pressure and velocity during co-extrusion, though it does increase manufacturing complexity compared to uniform thickness.
3Force
If symmetric thickness structure is used, then shearing force is reduced, but thickness control precision must be high
Solution Approach 1:
The patent applies parameter changes by systematically varying the thickness parameter across different regions of the multilayer reflective sheet. The thickness is designed to change gradually from the center toward the edges, creating a thickness gradient. This parameter variation reduces shearing forces during co-extrusion by balancing fluid pressure and velocity. The symmetric design around the central axis ensures that both sides experience similar thickness variations, thereby reducing overall shearing force while requiring precise thickness control to maintain the desired gradient profile.
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 approach reduces shearing forces and balances fluid dynamics during co-extrusion, enabling the production of high-optical-power multilayer reflective sheets with improved durability and reflectivity, while maintaining symmetrical thickness structures for enhanced performance.
Implementation Method 1
at least one of the polymer films is a birefringence material layer that conforms to the condition of NX≠NY≠NZ, wherein NX is the index of refraction of light at X direction of the multilayer reflective sheet, NY is the index of refraction of light at Y direction of the multilayer reflective sheet, and NZ is the index of refraction of light at Z direction of the multilayer reflective sheet
Data Source
AI summary
A reflective optical film includes a reflective light-polarizing unit including a multilayer reflective sheet composed of a plurality of polymer films stacked on top of one another. Each polymer film has a thickness, every two adjacent polymer films are two different materials, and the thicknesses of the polymer films are gradually decreased from two outmost sides of the multilayer reflective sheet to a middle of the multilayer reflective sheet. At least one of the polymer films is a birefringence material layer that conforms to the condition of NX≠NY≠NZ, where NX is the index of refraction of light at X direction of the multilayer reflective sheet, NY is the index of refraction of light at Y direction of the multilayer reflective sheet, and NZ is the index of refraction of light at Z direction of the multilayer reflective sheet.