Optical Sheet Warpage Reduction via Skirt Layer Elimination
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Solution Overview
Problem
Optical sheets with pole prisms on a transparent base often experience significant warpage due to resin shrinkage during curing, leading to display quality issues like Newton rings and flaws, especially when the base is thin, which affects the visibility and battery life of mobile display devices.
Innovation Solution
The optical sheet design eliminates the skirt layer between the transparent base and pole prisms by pressing the mother die projections directly onto the base, minimizing the height of the pole prisms and reducing resin volume, thus minimizing warpage and strain from resin shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the transparent base is made thin to reduce optical sheet thickness, then the optical sheet becomes thinner and more compact, but the base strength is lowered and warpage increases due to resin shrinkage
Solution Approach 1:
The invention removes the skirt layer that extends from the pole prism bottom to the transparent base, extracting the harmful element that causes warpage while preserving the functional pole prism structure
Solution Approach 2:
The invention changes the geometric parameters by minimizing pole prism height and eliminating the skirt layer thickness, thereby reducing the volume of hardening resin and its associated shrinkage warpage
2Illumination intensity
If the pole prism height is increased to improve light condensation, then light condensation performance is improved, but resin volume increases and warpage becomes more severe
Solution Approach 1:
The invention converts the harmful effect of resin shrinkage into a beneficial outcome by eliminating the skirt layer, so that the remaining minimal resin volume shrinks without causing warpage, while the pole prisms still achieve sufficient light condensation
3Strength
If the skirt layer is present to support the pole prisms, then structural support is provided, but the hardening resin volume increases and causes significant warpage during curing
Solution Approach 1:
The invention extracts and removes the skirt layer entirely, eliminating the source of warpage while the pole prisms maintain adequate support through their direct integration with the transparent base
Solution Approach 2:
Instead of extending the resin layer outward from the pole prism base (skirt layer), the invention inverts the approach by minimizing resin volume and allowing the transparent base to provide support directly
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 significantly reduces warpage and prevents display quality issues, allowing for thinner optical sheets with improved luminance and extended battery life in mobile devices without compromising visibility.
Implementation Method 1
the lens film is largely warped to the hardening resin side due to shrinkage due to curing of the hardening resin
Data Source
AI summary
A lens film with small warpage even when a transparent base is thin is provided. Pole prisms made of a hardening resin are arranged along the extending direction on a transparent base made of a flexible material. The transparent base has a depression according to a valley between the pole prisms adjacent to each other. The pole prism has a sloping face extending to an inner wall of the depression. The transparent base is in contact with the valley. A layer not functioning as a prism, that is, a so-called skirt layer does not exist between the transparent base and the pole prisms.