Liquid Crystal Display Blue Phase Stability via Selective Polymerization
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Solution Overview
Problem
In liquid crystal display devices, achieving uniform polymerization of photocurable resins across large substrate surfaces is challenging, leading to non-uniform alignment in liquid crystal layers and instability of the blue phase, resulting in display defects and reduced yield.
Innovation Solution
A method of selective polymerization is employed by scanning a liquid crystal layer with light between substrates, creating regions of varying polymerization degrees, where the sealant area is kept at a lower polymerization state to minimize alignment differences and enhance stability of the blue phase, using linear light irradiation and controlled temperature treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If light irradiation treatment is performed on the entire liquid crystal layer including the sealant region, then polymerization occurs uniformly across the substrate, but alignment nonuniformity arises between the sealant region and display region causing blue phase instability and display defects
Solution Approach 1:
The liquid crystal layer is divided into two distinct regions: a sealant region and a display region. Light irradiation treatment is selectively applied only to the display region, leaving the sealant region untreated. This segmentation allows different polymerization degrees in different regions, preventing alignment nonuniformity at the boundary while maintaining blue phase stability in the display region.
Solution Approach 2:
Different regions of the liquid crystal layer are given different qualities through selective light irradiation. The display region receives light irradiation to achieve desired polymerization and alignment, while the sealant region remains in its original state. This local differentiation ensures that each region has the appropriate properties for its function, eliminating display defects caused by boundary effects.
2Area of stationary object
If light irradiation treatment is performed on large-sized substrate surfaces, then the entire area can be treated, but uniform polymerization becomes difficult to achieve leading to alignment nonuniformity and display defects
Solution Approach 1:
The large substrate area is segmented into a sealant region and a display region. By treating only the display region with light irradiation, the patent avoids the uniformity problems that arise when attempting to treat the entire large substrate area uniformly. This selective treatment approach maintains manufacturing precision even on large substrates.
Solution Approach 2:
Instead of applying light irradiation to the entire liquid crystal layer (excessive action), the treatment is applied partially only to the display region. This partial action approach prevents the polymerization nonuniformity that would occur across the entire large substrate, thereby maintaining alignment uniformity and preventing display defects.
3Strength
If the polymerization degree of photocurable resin is increased in the sealant region, then structural stability is improved, but alignment differences between sealant region and display region increase causing blue phase instability
Solution Approach 1:
The patent segments the liquid crystal layer into sealant region and display region, and applies light irradiation only to the display region. This creates a deliberate difference in polymerization degree between regions: the sealant region remains with lower polymerization degree matching its original state, while the display region achieves higher polymerization degree. This segmentation prevents alignment nonuniformity at the boundary, maintaining blue phase stability while still providing structural stability to the sealant region through its original composition.
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 approach results in a stable blue phase across a larger region of the liquid crystal layer, reducing defects and increasing manufacturing yield while enabling high-speed response times of 1 msec or less, suitable for high-performance liquid crystal display devices.
Implementation Method 1
a photocurable resin is added to a liquid crystal material and the photocurable resin is polymerized with light
Data Source
AI summary
An object is to provide a highly reliable liquid crystal display device which includes a liquid crystal layer exhibiting a more stable blue phase. Another object is to provide a method for manufacturing a liquid crystal display device with high yield. Polymer stabilization treatment is performed as follows: a photocurable resin is added to a liquid crystal material exhibiting a blue phase, and the photocurable resin is selectively polymerized by scanning a liquid crystal layer provided between a first substrate and a second substrate with light in a certain direction. Thus, a first region where the light irradiation treatment is performed and a second region where the light irradiation treatment is not performed are formed in the liquid crystal layer. Since polymerization of the photocurable resin proceeds in the first region, the polymerization degree of the photocurable resin in the first region is higher than that in the second region.