Micro Concave-Convex Structure for Display Optical Body
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical bodies with micro concave-convex structures exhibit wavelength-dependent reflectance and high reflectance, failing to effectively suppress reflection across various wavelengths.
Innovation Solution
An optical body with a micro concave-convex structure on a transparent base material, featuring an average period of concavities and convexities equal to or shorter than a visible light wavelength, and increased standard deviation of bottom face and vertex positions to reduce reflectance, combined with a macro concave-convex structure for enhanced light scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a micro concave-convex structure with uniform concavity depths is formed on the base material, then the structure can be easily manufactured, but the reflectance fluctuates depending on the wavelength of incident light
Solution Approach 1:
The patent applies local quality by creating two distinct types of concavities with different depths: first concavities with a first depth and second concavities with a second depth greater than the first depth. This non-uniform depth distribution within the micro concave-convex structure allows different regions to handle different wavelengths of light, thereby reducing wavelength dependence of reflectance while maintaining manufacturability through selective etching processes
Solution Approach 2:
The patent segments the concave regions into two distinct depth categories (first concavities and second concavities) rather than using a uniform depth. This segmentation is achieved by forming a multi-layer resist structure with different thicknesses, where each layer corresponds to a different concavity depth, allowing the structure to address multiple wavelength ranges simultaneously
2Device complexity
If the micro concave-convex structure is formed using conventional methods, then the manufacturing process is simple, but the reflectance is high and insufficient suppression of reflection is achieved
Solution Approach 1:
The patent changes the depth parameter of the concavities by introducing a multi-layer resist structure with different thicknesses (first resist layer and second resist layer). This allows formation of concavities with two different depths, optimizing the anti-reflection performance across a broader wavelength range and achieving lower reflectance (Y value ≤ 0.2%) compared to conventional single-depth structures
3Ease of manufacture
If concavities with uniform depths are formed, then the structure is simple to produce, but it cannot effectively deal with incident light beams having various wavelengths
Solution Approach 1:
The patent implements local quality by creating first concavities and second concavities with different depths at different locations within the micro concave-convex structure. The first concavities (with smaller depth) handle shorter wavelengths while the second concavities (with greater depth) handle longer wavelengths, enabling the structure to adapt to various wavelengths incident on the base material
Solution Approach 2:
The patent segments the resist structure into multiple layers (first resist layer and second resist layer) with different thicknesses, which directly translates to concavities of different depths in the final structure. This segmentation enables the optical structure to handle multiple wavelength ranges, improving adaptability while maintaining a systematic manufacturing approach
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 optical body achieves reduced wavelength dependence and low reflectance across a wide spectrum, minimizing coloration and improving visibility in display devices.
Implementation Method 1
Since a refractive index of the surface on which the micro concave-convex structure is formed gently changes with respect to incident light, an abrupt change in the refractive index, which is the cause of reflection, does not occur.
Implementation Method 2
a macro concave-convex structure formed on the surface of the base material to be superimposed on the concave-convex structure
Data Source
AI summary
There is provided an optical body and a display device that enable wavelength dependence of a reflectance to be reduced and reflection of incident light to be further suppressed, the optical body including: a concave-convex structure formed on a surface of a base material. An average period of concavities and convexities of the concave-convex structure is equal to or shorter than a wavelength belonging to a visible light band. A standard deviation of differences between respective positions of bottom faces of the concavities of the concave-convex structure in a normal direction of a flat surface of the base material and a median of the positions of the bottom faces is greater than or equal to 25 nm.