Liquid Crystal Lens 90° Twist Alignment Reduces Crosstalk
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Solution Overview
Problem
Liquid crystal lenses with TN alignment suffer from crosstalk issues due to asymmetric refractive index distribution caused by electric field application, leading to mixing of right-eye and left-eye images in viewers.
Innovation Solution
A liquid crystal lens with a 90° twist alignment, utilizing a chiral agent and specific alignment film treatments on substrates to maintain TN alignment and control refractive index distribution, along with electrode configurations that satisfy the condition 3.5≦(p−w)/d≦4.5, where w is electrode width, p is electrode pitch, and d is liquid crystal layer thickness, to minimize crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TN alignment is used in liquid crystal lens, then transmittance in three-dimensional image display is reduced and alignment defects are prevented, but asymmetric refractive index distribution occurs when electric field is applied causing crosstalk
Solution Approach 1:
The patent applies asymmetry principle by introducing a chiral agent that creates a specific twist direction (90 degrees) in the liquid crystal molecules, which is opposite to the natural twist direction induced by the alignment films. This controlled asymmetric arrangement prevents the symmetric disturbance that causes crosstalk while maintaining the benefits of TN alignment.
Solution Approach 2:
The patent changes the physical parameter of liquid crystal molecular orientation by adding a chiral agent with specific helical twisting power. This parameter change modifies the twist angle and direction of liquid crystal molecules, enabling them to maintain proper alignment under electric field application and prevent asymmetric refractive index distribution.
2Manufacturing precision
If alignment films are used to achieve TN alignment, then initial alignment is improved, but alignment in the vicinity of electrode is disturbed when electric field is applied resulting in asymmetric refractive index distribution
Solution Approach 1:
The patent modifies the orientation parameter of liquid crystal molecules by adding a chiral agent that induces a specific twist angle (90 degrees) opposite to the alignment film-induced twist. This parameter change ensures that the liquid crystal molecules maintain their twisted nematic structure even when electric field is applied, preventing alignment disturbance near electrodes.
Solution Approach 2:
The patent introduces a controlled asymmetric twist direction through the chiral agent that counteracts the symmetric disturbance caused by the electric field. The chiral agent creates a predetermined asymmetric molecular arrangement that remains stable under electric field application, preventing the symmetric alignment disturbance that leads to crosstalk.
3Object-generated harmful factors
If chiral agent is added to induce twist opposite to alignment films, then crosstalk is reduced, but device complexity increases
Solution Approach 1:
The patent changes the chemical composition parameter of the liquid crystal layer by adding a chiral agent. This single parameter change (adding chiral dopant) achieves the complex goal of preventing crosstalk while maintaining TN alignment, simplifying the overall device structure compared to using multiple alignment films or complex electrode patterns.
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 reduces crosstalk by maintaining aligned liquid crystal molecules and controlling refractive index distribution, ensuring clear separation of left-eye and right-eye images and improving overall image display quality.
Implementation Method 1
the liquid crystal molecules in the liquid crystal layer are aligned, by the addition of a chiral agent to the liquid crystal layer, in a 90° twist in a second direction opposite to the first direction
Implementation Method 2
the first alignment film and the second alignment film are alignment films subjected to a rubbing treatment so that liquid crystal molecules in the liquid crystal layer are aligned in a 90° twist in a first direction
Implementation Method 3
a distribution characteristic of the refractive index is controlled by controlling a voltage to be applied to a liquid crystal layer
Data Source
AI summary
An image display device includes a liquid crystal lens on a display surface side of a display panel. The liquid crystal lens includes a first substrate, a second substrate, a liquid crystal layer interposed between the first substrate and the second substrate, a first alignment film and a second alignment film formed on an interface of the liquid crystal layer. The first alignment film and the second alignment film are alignment films subjected to a rubbing treatment so that liquid crystal molecules in the liquid crystal layer are aligned in a 90° twist in a first direction by the provision of a pretilt angle. The liquid crystal molecules are aligned, by the addition of a chiral agent to the liquid crystal layer, in a 90° twist in a second direction opposite to the first direction in a state where an electric field is not applied.