Liquid Crystal Display Device with Third Electrode for Viewing Angle Control
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Solution Overview
Problem
Existing liquid crystal display devices face challenges in achieving sufficient transmittance, contrast ratio, and privacy control, particularly from oblique and left-right directions, as they struggle to maintain image obscurity in wide viewing angles while ensuring visibility in narrow viewing angles.
Innovation Solution
A liquid crystal display device with a matrix-patterned sub-pixel structure, featuring an active matrix substrate, a liquid crystal layer, and a color filter substrate, where the third electrode is strategically positioned to avoid optical openings and apply alternating or constant voltage, combined with a control circuit for mode switching, and optionally includes a dielectric layer and black matrix for enhanced privacy and visibility control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a third electrode is added to generate vertical electric field for viewing angle control, then viewing angle characteristics are improved, but device complexity increases and manufacturing difficulty increases
Solution Approach 1:
The liquid crystal display device divides the electrode functions into multiple segments: first electrode and second electrode on the first substrate for lateral electric field generation, and third electrode on the second substrate for vertical electric field generation. This segmentation allows independent control of viewing angle characteristics through the third electrode without affecting the basic display function.
Solution Approach 2:
The patent introduces a dielectric layer as an intermediary between the third electrode and the liquid crystal layer. This dielectric layer mediates the electric field interaction, allowing the third electrode to control vertical electric field for viewing angle adjustment without directly contacting the liquid crystal, thus simplifying the overall structure and manufacturing process.
2Object-affected harmful factors
If third electrode is positioned to avoid optical openings for privacy control, then privacy protection is improved, but transmittance decreases
Solution Approach 1:
The third electrode is designed with spatially varying properties: in regions corresponding to optical openings (sub-pixel regions), the third electrode is positioned to avoid direct overlap, maintaining high transmittance; in regions between optical openings, the third electrode is positioned to generate vertical electric field for privacy control. This local quality differentiation resolves the contradiction between transmittance and privacy protection.
Solution Approach 2:
The third electrode applies vertical electric field partially - only in specific regions (non-optical opening areas) where privacy control is needed, rather than uniformly across the entire display. This partial action maintains high transmittance in optical opening regions while achieving privacy protection in other regions.
3Adaptability or versatility
If alternating voltage is applied to third electrode for mode switching, then adaptability is improved, but energy consumption increases
Solution Approach 1:
The control circuit applies alternating voltage periodically to the third electrode to switch between different display modes (wide viewing angle mode and narrow viewing angle mode). This periodic voltage application allows the liquid crystal molecules to reorient between different states, enabling mode switching while consuming energy only during transitions rather than continuously.
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 achieves high transmittance and contrast ratio while ensuring privacy by minimizing visibility from oblique and left-right directions through effective electric field management and mode switching, enhancing display quality and user privacy.
Implementation Method 1
voltage is applied to a liquid crystal composition sealed between paired substrates such that the alignment of liquid crystal molecules in the liquid crystal composition is changed according to the applied voltage, whereby the amount of light passing through the paired substrates is controlled
Implementation Method 2
liquid crystal display device having an FFS structure generating a lateral electric field between a first electrode and a second electrode on a first substrate
Implementation Method 3
a third electrode for generating a vertical electric field with the first electrode and the second electrode is arranged on a second substrate facing the first substrate
Data Source
AI summary
A liquid crystal display device includes: a liquid crystal panel including an active matrix substrate, a liquid crystal layer, and a color filter substrate in a stated order, the active matrix substrate including a first substrate, and a first electrode and second electrodes stacked with an insulating layer in between, the second electrodes arranged in the respective sub-pixels, the color filter substrate including a second substrate, a color filter, and a third electrode, either the first electrode or the second electrodes arranged with electrical connection over the sub-pixels, each of the sub-pixels provided with an optical opening, the third electrode not superimposed with at least a portion of each of the optical openings in a plan view and arranged with electrical connection, a control circuit configured to switch between application of alternating voltage and application of constant voltage to the third electrode.