Liquid Crystal Display Sealing Layer UV Curing
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Solution Overview
Problem
In liquid crystal displays manufactured using the One Drop Fill method, the liquid crystal comes into contact with uncured sealant, leading to contamination and misalignment issues, which affect image characteristics and reliability.
Innovation Solution
A liquid crystal display with a sealing layer made of light-curable resin or combination type resin, including a photopolymerization initiator with a content of 0.01 wt % to 1 wt % and a wavelength peak of 320 nm to 420 nm, is used, where the sealing layer overlaps UV-blocking wires, and the sealant is cured using light irradiation after forming the liquid crystal layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UV-curable sealant is used for sealing the liquid crystal layer, then the sealing layer can be cured efficiently, but the liquid crystal comes into contact with uncured sealant causing contamination and misalignment
Solution Approach 1:
The patent applies preliminary action by forming the sealing layer before dropping the liquid crystal material. This ensures that the sealant is in place and can be cured before the liquid crystal is introduced, preventing contact between the liquid crystal and uncured sealant. The sealing layer is formed in a first state, then the liquid crystal is dropped, and finally the sealant is cured in a second state, eliminating the harmful contact that would occur if curing happened before sealing layer formation.
Solution Approach 2:
The patent segments the manufacturing process into distinct stages: (1) forming the sealing layer in a first state, (2) dropping the liquid crystal material, and (3) curing the sealant in a second state. This segmentation separates the sealant formation and curing operations from the liquid crystal filling operation, preventing contamination while ensuring proper sealing. The process is divided into temporal and functional segments to eliminate the harmful interaction between liquid crystal and uncured sealant.
2Object-affected harmful factors
If the sealing layer is formed before dropping liquid crystal, then liquid crystal contamination is prevented, but the sealant curing may be inhibited by the liquid crystal
Solution Approach 1:
The patent uses an intermediary approach by introducing a light-shielding layer between the sealing layer and the liquid crystal. This light-shielding layer acts as a mediator that blocks UV light from reaching the liquid crystal during the curing process, preventing the liquid crystal from absorbing UV energy and becoming contaminated or misaligned. The light-shielding layer allows the sealant to cure efficiently while protecting the liquid crystal from harmful UV exposure, thus resolving the conflict between preventing contamination and ensuring proper curing.
3Reliability
If conventional sealant curing is used, then sealing is achieved, but misalignment occurs in the vicinity of the sealant affecting image characteristics
Solution Approach 1:
The patent introduces a light-shielding layer as an intermediary between the sealing layer and the liquid crystal/alignment film. This light-shielding layer selectively blocks UV light in the region where the sealing layer is present, preventing UV-induced misalignment of the alignment film in the vicinity of the sealant. The light-shielding layer allows UV light to pass through to the liquid crystal for proper curing while simultaneously protecting the alignment film from UV exposure that would cause misalignment, thus resolving the precision issue without compromising sealing functionality.
Solution Approach 2:
The patent applies local quality by making the light-shielding layer selectively transparent in specific regions. The light-shielding layer is designed to block UV light in the sealing region to prevent misalignment, while remaining transparent in other regions to allow UV light through for liquid crystal curing. This localized differentiation of optical properties enables the system to simultaneously achieve proper sealing and maintain alignment precision by applying different UV transmission characteristics to different spatial locations.
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
This solution prevents contamination and misalignment, enhancing the reliability and image quality of the liquid crystal display by ensuring efficient curing of the sealant without damaging the liquid crystal or alignment film.
Implementation Method 1
a sealing layer made of a light-curable resin or a combination type resin, including a photopolymerization initiator
Implementation Method 2
the photopolymerization initiator has a wavelength peak of 320 nm to 420 nm
Implementation Method 3
one of the pair of substrates including a wire made of a material blocking an ultraviolet ray in the surrounding region
Data Source
AI summary
A liquid crystal display includes: a pair of substrates having display regions in positions facing each other and surrounding regions around the display regions, respectively, one of the pair of substrates including a wire made of a material blocking an ultraviolet ray in the surrounding region; a liquid crystal layer sandwiched between the pair of substrates; and a sealing layer arranged so as to overlap a part or the whole of the wire in a direction where the pair of substrates face each other, and sealing the liquid crystal layer, in which the sealing layer is made of a light-curable resin or a combination type resin and includes a photopolymerization initiator, and the content of the photopolymerization initiator is within a range of 0.01 wt % to 1 wt %, and the photopolymerization initiator has a wavelength peak of 320 nm to 420 nm.