Liquid Crystal Alignment Film Refractive Index Gradient
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Solution Overview
Problem
Existing liquid crystal display devices face challenges in achieving high transmissivity without degrading low power consumption or alignment properties, particularly due to insufficient liquid crystal alignment capability and increased power consumption when using external light reflection prevention films or GRIN thin films made of SiOx.
Innovation Solution
A liquid crystal display device is designed with an alignment film that includes an organic compound with a monotonic increase in refractive index from the boundary surface with the liquid crystal layer to the underlying layer, ensuring the refractive indices of the liquid crystal layer, alignment film, and underlying layer satisfy specific relationships to minimize reflection loss and maintain alignment capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an external light reflection prevention film or GRIN thin film made of SiOx is used, then reflection loss is reduced, but liquid crystal alignment capability is insufficient and power consumption increases
Solution Approach 1:
The patent changes the refractive index parameter of the alignment film by using organic compounds with specific refractive indices (1.6-1.7) and controlling the refractive index gradient from the liquid crystal layer interface to the underlying layer. This parameter optimization enables the film to maintain both low power consumption and effective liquid crystal alignment capability simultaneously
Solution Approach 2:
The patent employs composite material structure combining organic compounds with specific refractive index properties in the alignment film. The composite approach allows the film to exhibit both optical properties (refractive index matching) and functional properties (liquid crystal alignment) that single materials cannot provide
2Illumination intensity
If the refractive index of the alignment film is increased to reduce reflection loss, then transmissivity is improved, but liquid crystal alignment capability may be degraded
Solution Approach 1:
The patent applies local quality by creating a refractive index gradient within the alignment film thickness direction. The refractive index is higher near the liquid crystal layer interface (to reduce reflection) and gradually decreases toward the underlying layer (to maintain alignment capability). This spatial variation of refractive index allows simultaneous optimization of both transmissivity and alignment performance
Solution Approach 2:
The patent optimizes the refractive index parameter distribution within the alignment film, using organic compounds with controlled refractive indices (1.6-1.7) and implementing a gradient profile. This parameter control enables the film to achieve high transmissivity through reduced reflection while preserving liquid crystal alignment capability through appropriate refractive index matching at the interface
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 achieves high transmissivity while maintaining low power consumption and effective liquid crystal alignment, improving the overall performance of the liquid crystal display device by optimizing the refractive index relationships and using a polyimide-based alignment film with photo-alignment treatment.
Implementation Method 1
the refractive index of the alignment film monotonically increases from a boundary surface between the alignment film and the liquid crystal layer to a boundary surface between the alignment film and the underlying layer
Implementation Method 2
light reflecting at a boundary surface originating from a difference in refractive index between optical thin films
Implementation Method 3
an alignment direction of a liquid crystal molecule changes when applying an electric field to the liquid crystal molecule of a liquid crystal layer
Implementation Method 4
an image is displayed by using birefringence of the liquid crystal layer
Implementation Method 5
the alignment direction of the liquid crystal molecule is determined by an alignment film obtained by performing a rubbing treatment on a surface of a polyimide thin film
Implementation Method 6
using a polyimide-based alignment film with photo-alignment treatment
Data Source
AI summary
A liquid crystal display device includes first and second substrates, at least one of which is transparent, a liquid crystal layer which is disposed between the first and second substrates, a pixel electrode and a common electrode which are formed on one of the first and second substrates and which apply an electric field to the liquid crystal layer, a plurality of active elements which is connected to the pixel electrode and the common electrode, an alignment film which is disposed on at least one of the first and second substrates and has one surface contacting the liquid crystal layer, and an underlying layer which is disposed on at least one of the first and second substrates and contacts the other surface of the alignment film. The pixel electrode is laminated on the common electrode having a plane shape through an isolation film.