Curved Liquid Crystal Display Pretilt Alignment via Photopolymerized Protrusions
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Solution Overview
Problem
Liquid crystal displays with curved shapes face texture defects due to misalignment of liquid crystal molecules, leading to luminance changes and image quality issues when bent, as existing technologies fail to maintain uniform alignment across substrates.
Innovation Solution
A liquid crystal display design featuring a first substrate with a photoinitiator-based alignment layer and protrusions formed from a polymerization product of the photoinitiator, reactive mesogen, and vertical alignment additive, while the second substrate lacks an alignment layer and protrusions, resulting in distinct pretilt angles between substrates to prevent texture formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a curved display device is created to improve immersion, then viewer engagement is enhanced, but texture defects and image quality degradation occur due to liquid crystal molecule misalignment
Solution Approach 1:
The patent applies different alignment conditions to different locations: the first substrate has an alignment layer with photoinitiator and protrusions that create pretilt alignment, while the second substrate has no alignment layer allowing vertical alignment. This local differentiation prevents texture defects in curved displays by ensuring proper liquid crystal orientation at each substrate interface.
2Manufacturing precision
If an alignment layer with photoinitiator and protrusions is added to the first substrate, then liquid crystal pretilt alignment is achieved, but device complexity increases
Solution Approach 1:
The alignment layer is prepared in advance with photoinitiator molecules and protrusion structures before liquid crystal injection. The protrusions are pre-formed to guide liquid crystal orientation, and the photoinitiator is pre-positioned to enable subsequent photoalignment processing. This preliminary preparation ensures precise pretilt alignment without adding complex real-time control mechanisms.
3Ease of manufacture
If the vertical alignment additive is made less reactive than the photoinitiator, then selective polymerization occurs to form protrusions only at the first substrate, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the reactivity parameter of the vertical alignment additive by selecting compounds with lower reactivity than the photoinitiator. This parameter difference ensures that during UV irradiation, the photoinitiator polymerizes first to form protrusions at the first substrate, while the less reactive vertical alignment additive remains unpolymerized and stays in the liquid crystal layer to provide vertical alignment without forming unwanted protrusions at the second substrate.
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 effectively prevents texture occurrence by ensuring liquid crystal molecules adjacent to the first substrate have a pretilt angle, while those near the second substrate are aligned perpendicular, reducing luminance changes and maintaining image quality even when the display is curved.
Implementation Method 1
the plurality of protrusions comprise a polymerization product of the photoinitiator, a reactive mesogen, and a vertical alignment additive
Data Source
AI summary
A liquid crystal display includes: a first substrate; a second substrate overlapping the first substrate and spaced apart therefrom; a liquid crystal layer between the first substrate and the second substrate and including liquid crystal molecules; a first alignment layer between the first substrate and the liquid crystal layer; and a plurality of protrusions between the first alignment layer and the liquid crystal layer, wherein the first alignment layer includes a photoinitiator, wherein the plurality of protrusions include a polymerization product of the photoinitiator, a reactive mesogen, and a vertical alignment additive, and the vertical alignment additive may be less reactive than the photoinitiator.