Liquid Crystal Device Antireflective Structure for Uneven Substrates
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Solution Overview
Problem
Reflection type liquid crystal display apparatuses face challenges in maintaining an effective antireflection function when formed on substrates with uneven surfaces, leading to potential deformation of the light antireflection structure and reduced brightness due to interference fringes.
Innovation Solution
A liquid crystal device configuration featuring a planarization layer with a refractive index matching the second substrate, combined with light-transmissive films of varying refractive indices, ensures that light antireflection is maintained without being affected by surface irregularities, and includes a hygroscopic planarization layer for moisture resistance, preventing water or gas penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the antireflection film is formed directly on the substrate with uneven surface, then the antireflection function is achieved, but the film structure is damaged and deformed due to surface irregularities
Solution Approach 1:
A planarization layer is introduced as an intermediary between the substrate and the antireflection film. This planarization layer serves as a mediator that provides a flat surface for film formation while allowing the underlying substrate's uneven surface to remain unchanged. The planarization layer has a refractive index of 1.5 or higher to maintain optical compatibility while mechanically protecting the antireflection film from surface irregularities.
2Illumination intensity
If the antireflection film thickness is reduced to below 100 nm, then the interference fringe is reduced, but the film is more susceptible to deformation on uneven substrates
Solution Approach 1:
The planarization layer acts as a protective intermediary that enables the use of thin antireflection films (below 100 nm) without compromising structural stability. By providing a flat, stable surface for film deposition, the planarization layer prevents deformation even when the antireflection film is made extremely thin to optimize light transmission and minimize interference fringes.
3Illumination intensity
If the planarization layer has high refractive index, then light antireflection is enhanced, but the layer may become susceptible to moisture penetration
Solution Approach 1:
The planarization layer is formed as a composite structure combining inorganic material (silicon oxide with refractive index ≥1.5) and organic material (polymer layer). This composite structure provides both the optical properties needed for light antireflection and the moisture barrier properties needed for protection. The inorganic layer provides high refractive index for optical performance while the organic polymer layer provides moisture resistance.
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 configuration achieves a bright display with high reliability and moisture resistance by minimizing light attenuation and interference fringes, ensuring effective light antireflection across the visible wavelength range.
Implementation Method 1
a light antireflection structure is formed in the second substrate, the intensity thereof is finished without attenuation when an incident light and a reflective light are transmitted through the second substrate
Implementation Method 2
it is possible to reduce an interference fringe generated due to the interference of the reflective light and light incident to the transparent substrate
Implementation Method 3
a planarization layer with a refractive index matching the second substrate, combined with light-transmissive films of varying refractive indices
Data Source
AI summary
A liquid crystal layer is disposed between an element substrate and an opposite substrate and a pixel electrode being light-reflective is disposed between an element substrate and a liquid crystal layer, and a planarization layer that is light-transmissive, a first light-transmissive film that has a high refractive index than a refractive index of the planarization layer, a second light-transmissive film that has a lower refractive index than the refractive index of the first light-transmissive film, and a third light-transmissive film that is electrically conductive and has a higher refractive index than the refractive index of the second light-transmissive film are disposed between the opposite substrate and the liquid crystal layer from the opposite substrate side in this order.