Liquid Crystal Display Panel High Temperature Stability
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Solution Overview
Problem
Conventional liquid crystal display devices face issues with image quality and afterimage defects when exposed to high temperatures or ultraviolet light, due to the chemical reactivity of alkenyl-based liquid crystal molecules, leading to abnormal driving properties and blackening phenomena.
Innovation Solution
A liquid crystal display panel with a liquid crystal layer having liquid crystal molecules with a negative dielectric anisotropy, a nematic-isotropic phase transition temperature of 110° C or more, and specific molecular structures that exclude alkenyl-based molecules, combined with a high rotational viscosity and elastic moduli, allowing stable operation at high temperatures and improved response times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If alkenyl-based liquid crystal molecules are used, then the liquid crystal layer can be manufactured with conventional materials, but the display device exhibits chemical reactivity leading to blackening phenomena and afterimage defects at high temperatures
Solution Approach 1:
The patent changes the chemical structure parameters of liquid crystal molecules by excluding alkenyl-based molecules and specifying particular molecular structures with defined length-to-width ratios. This parameter change eliminates chemical reactivity issues while maintaining manufacturability through standardized synthesis processes.
Solution Approach 2:
The patent extracts and removes the problematic alkenyl-based liquid crystal molecules from the composition. By taking out the harmful component and replacing it with alternative molecular structures, the patent eliminates afterimage defects and blackening phenomena while preserving display functionality.
2Reliability
If liquid crystal molecules with high nematic-isotropic phase transition temperature are used, then stable operation at high temperatures is achieved, but the response time increases
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: selecting liquid crystal molecules with specific length-to-width ratios (6.3 or more), controlling the nematic-isotropic phase transition temperature to be 110°C or more, and adjusting rotational viscosity to 190 mPa·s or more. These coordinated parameter changes achieve high-temperature stability while managing response time through the interplay of elastic moduli and viscosity.
Solution Approach 2:
The patent creates a composite liquid crystal composition by combining specific molecular structures with defined physical properties. The composite nature of the liquid crystal layer, with its optimized mixture of molecules having particular geometries and interaction characteristics, allows simultaneous optimization of stability and response properties that cannot be achieved with single-component systems.
3Reliability
If liquid crystal molecules with high rotational viscosity are used, then high-temperature stability is improved, but the response time of the display device increases
Solution Approach 1:
The patent carefully controls the rotational viscosity parameter to be 190 mPa·s or more while simultaneously optimizing the elastic moduli (splay elastic modulus of 17 or more, bending elastic modulus of 19 or more). This coordinated parameter adjustment ensures that the increased viscosity provides thermal stability without excessively slowing the response, as the elastic forces compensate for the viscous damping.
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 enables stable operation at high temperatures, reduces afterimage defects, and maintains image quality comparable to conventional devices, with increased rotational viscosity and elastic moduli compensating for increased response times, while providing high luminance to offset transmittance decreases.
Implementation Method 1
A liquid crystal display device displays an image by changing the light transmittance of the liquid crystal layer according to an electric field formed between each of the pixel electrodes and the common electrode
Implementation Method 2
liquid crystal molecules that have a negative dielectric anisotropy and a nematic-isotropic phase transition temperature (Tni) at about 110° C. or more
Data Source
AI summary
A liquid crystal display panel includes a first substrate, a second substrate that faces the first substrate, and a liquid crystal layer interposed between the first substrate and the second substrate. The liquid crystal layer includes liquid crystal molecules that have negative dielectric anisotropy and a nematic-isotropic phase transition temperature (Tni) of about 110° C. or more.