OCB LCD Protrusion Lines for Bend Transition
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Solution Overview
Problem
Existing LCD devices with OCB mode struggle to achieve sufficient bend transition efficiently, leading to high power consumption and prolonged transition times due to the lack of defined protrusion locations according to rubbing direction, which complicates the formation of stable bend alignment.
Innovation Solution
The implementation of lower and upper protrusion lines with sloping sides, crossing the alignment direction, and an opposite electrode formed on the upper protrusion line, which increases the pretilt angle of liquid crystals and facilitates a rapid bend transition by creating a stronger electric field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high electric field is applied to achieve bend transition in OCB mode LCD, then the liquid crystals can be reoriented to form images, but the power consumption increases significantly
Solution Approach 1:
The alignment layers are pre-rubbed in a specific direction to create pretilt angles that facilitate bend transition. This preliminary action reduces the voltage needed during operation to achieve the same liquid crystal reorientation, thereby lowering power consumption while ensuring reliable bend transition.
2Reliability
If voltage is increased to prevent non-bend-transited pixels, then all liquid crystals can be properly transitioned, but the transition time increases
Solution Approach 1:
The alignment layers are rubbed in different directions in different regions of the liquid crystal layer. This creates locally optimized pretilt angles that promote uniform bend transition across all pixels, ensuring consistent transition behavior without requiring excessive voltage that would prolong the overall transition time.
3Reliability
If protrusions are added to the electrode structure, then the pretilt angle increases and bend transition is promoted, but the device complexity increases
Solution Approach 1:
Instead of adding complex three-dimensional protrusions, the invention segments the alignment layer rubbing process into distinct directional patterns. The alignment layers are rubbed in specific directions (e.g., horizontal in lower alignment layer, vertical in upper alignment layer) to create the desired pretilt angles, achieving bend alignment stability without increasing structural complexity.
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 reduces the bend transition time and voltage requirements, stabilizes the bend alignment, and prevents degradation of display quality by ensuring sufficient bend transition across the liquid crystal layer, enabling faster response times and improved image formation.
Implementation Method 1
Liquid crystal molecules of the liquid crystal layer are aligned to have a predetermined angle to a surface of the substrate along a tilt angle of the protrusions by an anchoring force of the alignment layer
Implementation Method 2
The OCB mode LCD device includes a pixel electrode, a lower alignment layer, an opposite electrode, an upper alignment layer, and a liquid crystal layer having a positive dielectric constant anisotropy Δ∈
Implementation Method 3
a high electric field should be formed between the pixel electrode and the opposite electrode. The high electric field changes a tilt angle of the liquid crystals located at a central portion of the liquid crystal layer to an angle of 90° so that the liquid crystals have a bend alignment
Data Source
AI summary
A liquid crystal display device includes: a pixel electrode located on a lower substrate; a lower alignment layer located on the pixel electrode and having a predetermined alignment direction (or aligned in a predetermined direction); an upper substrate located apart from the lower substrate and having an opposite surface facing the lower substrate; an opposite electrode located on the opposite surface; an upper alignment layer located on the opposite electrode and having the predetermined alignment direction of the lower alignment layer; an upper protrusion line located between the upper substrate and the upper alignment layer and arranged in a direction crossing the predetermined alignment direction; and an optically compensated bend (OCB) mode liquid crystal layer located between the lower alignment layer and the upper alignment layer.