Liquid Crystal Lens Rubbing Angle Symmetry
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Solution Overview
Problem
Existing electrically-driven liquid crystal lenses face challenges in achieving a gentle parabolic lens surface and symmetry due to steep lateral electric fields and inadequate alignment control, especially in large-area displays, leading to discontinuous lens profiles and asymmetry.
Innovation Solution
The solution involves defining a rubbing direction for the alignment film between 30˜90 degrees with respect to the electrode's longitudinal direction, combined with finely split electrodes and varying voltages applied across the lens regions, to create a vertical electric field and control liquid crystal alignment, thereby achieving a symmetrical and parabolic optical path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If electrodes are arranged in a conventional parallel configuration with rubbing direction parallel to electrode length, then the device structure is simple, but the lens profile becomes distorted and asymmetry occurs due to steep lateral electric fields
Solution Approach 1:
The patent applies asymmetry by deliberately setting the rubbing direction at an angle (30-60 degrees) relative to the electrode longitudinal direction, rather than parallel to it. This asymmetric alignment configuration transforms the liquid crystal molecule orientation, creating a more uniform electric field distribution that eliminates lateral field distortions and achieves symmetric lens profiles despite the asymmetric rubbing angle.
Solution Approach 2:
The patent changes the rubbing direction parameter from the conventional parallel alignment (0 degrees) to an angled alignment (30-60 degrees) relative to the electrode longitudinal direction. This parameter change fundamentally alters the electric field distribution characteristics, reducing lateral field strength and enabling the formation of gentle parabolic lens surfaces with improved symmetry.
2Power
If high voltages are applied to create strong electric fields for lens formation, then the lens effect is enhanced, but lateral electric fields cause liquid crystal alignment distortion and profile discontinuity
Solution Approach 1:
By setting the rubbing direction at an asymmetric angle (30-60 degrees) to the electrode longitudinal direction, the patent modifies how liquid crystal molecules respond to the electric field. This asymmetric configuration causes the molecules to align in a pattern that distributes electric field stress more uniformly, preventing the lateral field-induced distortions that would otherwise occur at high voltages.
Solution Approach 2:
The patent changes the molecular alignment parameter by applying rubbing at a specific angle range (30-60 degrees). This parameter modification allows the liquid crystal layer to maintain stable, uniform alignment even under high voltage conditions, as the angled rubbing direction creates a more favorable energy state that resists lateral field disruption.
3Ease of manufacture
If rubbing direction is parallel to electrode longitudinal direction, then the alignment process is simple, but lens symmetry deteriorates due to horizontal electric field effects
Solution Approach 1:
The patent employs asymmetric rubbing angle configuration (30-60 degrees from electrode longitudinal direction) to achieve symmetric lens profiles. This counterintuitive approach uses the asymmetric rubbing to create a molecular alignment pattern that naturally compensates for horizontal electric field effects, resulting in symmetric light modulation across the lens aperture.
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 configuration enhances lens symmetry and profile, reducing the impact of horizontal electric fields on liquid crystal alignment, resulting in a more effective and symmetrical electrically-driven liquid crystal lens with improved refractive index distribution.
Implementation Method 1
a first alignment film formed over the entire surface of the first substrate including the first electrodes, the first alignment film being subjected to rubbing by an angle of 30 ̃90 degrees with respect to a longitudinal direction of the first electrodes and being aligned to have a pretilt angle
Implementation Method 2
Liquid crystal molecules of the liquid crystal layer are driven by an electric field created when voltages are applied to the two electrodes. The liquid crystal molecules have polarization and optical anisotropy characteristics.
Implementation Method 3
optical anisotropy refers to a change in path or polarization of light to be emitted according to an incidence direction or polarization of incident light, which is caused by an elongated shape of liquid crystal molecules and the above-mentioned molecular arrangement direction
Implementation Method 4
voltages gradually increasing from a center to an edge of each lens region being applied to the respective first electrodes... create a vertical electric field
Data Source
AI summary
Disclosed are an electrically-driven liquid crystal lens in which a rubbing direction is defined in a range of 30˜90 degrees with respect to a longitudinal direction of an electrode, achieving an improved lens profile and lens symmetry, and a stereoscopic display device using the same.