Asymmetric Viewing Angle Control in Liquid Crystal Displays
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Solution Overview
Problem
Liquid crystal display devices lack the ability to provide different viewing angle characteristics between observation from the left direction and the right direction, with existing technologies failing to effectively control viewing angles between these directions.
Innovation Solution
A liquid crystal display device incorporating a liquid crystal panel with sub-pixels arranged in a matrix pattern, featuring an active matrix substrate, alignment films, and a counter substrate, where the control circuit switches between applying alternating and constant voltages to a third electrode to achieve asymmetric viewing angle characteristics. This configuration includes a third electrode with a specific width ratio to the first electrode and utilizes a veil-view function to display different images based on viewing angle ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional liquid crystal display device is used, then the viewing angle characteristics are symmetric between left and right directions, but the ability to provide different viewing angle characteristics between left and right directions is lost
Solution Approach 1:
The patent introduces a third electrode on the counter substrate that is positioned asymmetrically relative to the first electrode on the active matrix substrate. Specifically, the third electrode is located at a lateral position that does not align with the first electrode, creating an asymmetric electrode configuration. This asymmetry enables different electric field distributions when voltage is applied, thereby achieving different viewing angle characteristics between left and right observation directions without requiring complete structural redesign of the display device
Solution Approach 2:
The patent adds a lateral position dimension to the electrode configuration by positioning the third electrode at a specific lateral offset from the first electrode. This dimensional adjustment in the electrode layout enables asymmetric electric field formation in the liquid crystal layer, which in turn creates asymmetric optical properties and viewing angle characteristics. The lateral positioning parameter becomes a controllable variable for adjusting the degree of asymmetry in viewing angle performance
2Manufacturing precision
If the third electrode width ratio is increased, then asymmetric electric field formation is improved, but the device complexity increases
Solution Approach 1:
The patent defines a specific parameter range for the width ratio of the third electrode to the first electrode (0.05 ≤ width ratio < 0.5). By establishing this quantitative parameter range, the patent transforms the complex problem of asymmetric electrode design into a controllable parameter optimization task. Within this specified range, the electrode configuration achieves effective asymmetric electric field formation while maintaining manufacturability and avoiding excessive complexity in electrode fabrication and alignment
3Adaptability or versatility
If alternating voltage is applied to the third electrode, then narrow viewing angle mode is achieved, but the viewing angle range is limited
Solution Approach 1:
The patent enables dynamic switching between different display modes by controlling the voltage applied to the third electrode. When alternating voltage is applied, the liquid crystal molecules exhibit a first alignment state providing narrow viewing angle characteristics. When direct voltage is applied, the molecules transition to a second alignment state providing wide viewing angle characteristics. This dynamic voltage control allows the display device to adapt its viewing angle properties in real-time, offering both privacy protection mode and public viewing mode without physical reconfiguration
Solution Approach 2:
The patent utilizes voltage type (alternating vs. direct) as a control parameter to switch between different display modes. By changing this electrical parameter, the liquid crystal alignment state changes, which in turn changes the viewing angle characteristics. This parameter-based control mechanism provides ease of operation, as mode switching can be achieved through simple voltage signal changes without mechanical adjustment or complex control sequences
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 the liquid crystal display device to provide distinct viewing angle characteristics between left and right directions, enhancing privacy and display efficiency by controlling the voltage applied to the third electrode, allowing for observable images in narrow or wide viewing angles as needed.
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
Implementation Method 2
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 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
Implementation Method 4
circuitry being adapted to apply an electric field in first and second different ways in the first and second sets of regions respectively, wherein a display can be switched between a public mode and a private mode
Data Source
AI summary
Provided is a liquid crystal display device including: a liquid crystal panel; and a control circuit, the liquid crystal panel sequentially including an active matrix substrate, a first alignment film, a liquid crystal layer, a second alignment film, and a counter substrate, the active matrix substrate sequentially including a first substrate, a first electrode, a first insulating layer, and a second electrode including a linear electrode portion, the counter substrate including a second substrate and a third electrode, the third electrode extending in a longitudinal direction of the sub-pixel at a right or left end of the sub-pixel, a ratio of a width of the third electrode to a width of the first electrode in a widthwise direction being 0.14 or greater and 0.25 or smaller, the control circuit being configured to switch between application of an alternating voltage and application of a constant voltage to the third electrode.