Display Substrate AlON Hard Coat Multilayer Refractive Index
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Solution Overview
Problem
Display device substrates face challenges in achieving both high durability and minimizing color shift, particularly in touchscreen panels where mechanical durability and optical characteristics need to be balanced.
Innovation Solution
A substrate structure comprising a base substrate with multiple coating films, including a hard coat film made of AlON, arranged in a specific refractive index sequence to enhance durability and reduce color shift, with the hard coat film being significantly thicker than the other films to withstand millions of touches while maintaining superior optical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a hard coat film is made thicker to improve durability, then mechanical strength is improved, but color shift increases due to optical interference
Solution Approach 1:
The patent divides the single hard coat film into multiple thin coating films (first through fourth coating films) with alternating high and low refractive indices, plus a separate hard coat film layer. This segmentation allows each layer to be optimized for specific functions: the multilayer structure controls optical interference to minimize color shift, while the hard coat film provides mechanical durability.
Solution Approach 2:
The patent uses composite material structure by combining multiple coating films with different refractive indices (alternating high and low refractive index materials) to create a multilayer interference structure. This composite approach enables simultaneous optimization of optical properties (minimizing color shift) and mechanical properties (providing durability through the hard coat film).
2Object-affected harmful factors
If multiple coating films are added to minimize color shift, then optical characteristics are improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by assigning specific functions to different layers: the first through fourth coating films are specifically designed with alternating refractive indices to control optical interference and minimize color shift, while the hard coat film is specifically designed for mechanical protection. Each layer's properties are locally optimized for its specific function.
Solution Approach 2:
The patent controls the thickness of each coating film to be less than one-quarter of the wavelength of visible light, which is a critical parameter change that prevents strong optical interference effects. This parameter control allows multiple layers to be stacked without creating significant color shift, managing complexity through precise dimensional control.
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 substrate achieves superior durability and minimized color shift, effectively supporting touchscreen panels by enhancing mechanical strength and optical performance through the multilayer structure of AlON and other refractive index layers.
Implementation Method 1
a first coating film disposed on the base substrate; a second coating film disposed on the first coating film, the second coating film being formed of a material, the refractive index of which is lower than that of the first coating film; a third coating film disposed on the second coating film, the third coating film being formed of a material, the refractive index of which is higher than that of the second coating film
Data Source
AI summary
The present invention relates to a substrate for a display device and, more particularly, to a substrate for a display device which has excellent durability and also can minimize generation of color shift when being applied to a display device. To this end, the present invention provides a substrate for a display device comprising: a base material; a first coating film formed on the base material; a second coating film which is formed on the first coating film and is formed of a material having a relatively lower refractive index than the first coating film; a third coating film which is formed on the second coating film and is formed of a material having a relatively higher refractive index than the second coating film; a forth coating film which is formed on the third coating film and is formed of a material having a relatively lower refractive index than the third coating film; and a hard coating film which is formed on the fourth coating film and is formed of AlON having a relatively higher refractive index than the forth coating film.