Dual-Layer Antireflection Optical Body for Display Devices
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Solution Overview
Problem
Conventional antireflection technologies, such as those employing wet etching, result in micro concave-convex structures on antiglare surfaces where projecting parts extend normal to the tangent plane at each position, leading to reduced antireflection capability when faced with strong external light, particularly from the front.
Innovation Solution
An optical body featuring a macro concave-convex structure with a superimposed micro concave-convex structure where the projecting parts of the micro structure extend normal to the flat plane of the base material, achieved through a manufacturing method involving the formation of a resist layer and etching with perpendicular anisotropy, allowing for improved alignment and antireflection performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet etching is used to form the micro concave-convex structure, then the structure is formed isotopically on the surface, but the projecting parts extend normal to the tangent plane at each position, reducing antireflection capability for strong external light from the front
Solution Approach 1:
The patent replaces wet etching (chemical/mechanical process) with a two-step process combining resist formation and anisotropic etching. The resist layer acts as a mask to control the etching direction, ensuring projecting parts extend normal to the base material plane rather than following the tangent plane orientation, thereby maintaining antireflection capability while preserving ease of manufacture
Solution Approach 2:
The patent introduces a resist layer as an intermediary element between the base material and the etching process. This resist layer serves as a protective mask that directs the etching action, enabling the formation of micro concave-convex structures with projecting parts oriented normal to the base material plane, thus resolving the contradiction between manufacturing ease and antireflection performance
2Adaptability or versatility
If the micro concave-convex structure is superimposed on the macro concave-convex structure, then both antireflection and antiglare properties are achieved, but the alignment of projecting parts becomes misaligned with the normal direction of the base material
Solution Approach 1:
The patent applies preliminary action by forming the resist layer on the base material before etching the micro concave-convex structure. This resist layer pre-establishes the correct orientation reference, ensuring that when the micro structure is etched, its projecting parts align normal to the base material plane rather than following the macro structure's tangent plane orientation, thereby achieving both optical properties and alignment precision
Solution Approach 2:
The patent applies local quality by making the etching process anisotropic through the resist mask, creating different etching rates in different directions. The etching proceeds vertically normal to the base material plane rather than isotropically following the surface orientation, enabling local control over the projecting parts' orientation to achieve proper alignment while maintaining both antireflection and antiglare properties
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
The solution enhances antireflection capability and antiglare properties by ensuring projecting parts of the micro concave-convex structure align normal to the base material, effectively suppressing regular reflection and maintaining high light transmittance and haze values, thereby improving optical body performance under strong external light conditions.
Implementation Method 1
At the surface having such a micro concave-convex structure, a refractive index changes gradually with respect to incident light, and thus a steep change in refractive index, which causes reflection, does not occur.
Implementation Method 2
a step of forming a first concave-convex structure on a surface of the base material; and a step of forming a second concave-convex structure on a surface of the first concave-convex structure by etching with perpendicular anisotropy
Data Source
AI summary
There is provided an optical body with improved antireflection capability, a display device, and a method for manufacturing an optical body, the optical body including: a first concave-convex structure formed on a surface of a base material; and a second concave-convex structure superimposed on the first concave-convex structure. An average concave-convex period of the first concave-convex structure is larger than a wavelength in a visible light region, an average concave-convex period of the second concave-convex structure is less than or equal to the wavelength in the visible light region, and projecting parts of the second concave-convex structure extend in a direction normal to a flat plane of the base material.