Liquid Crystal Display Viewing Angle Switching via Bias Electrode Segmentation
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Solution Overview
Problem
Current liquid crystal display devices face issues with switching between wide and narrow viewing angles, resulting in vertical or horizontal dark lines due to the high impedance of transparent conductive electrodes, which affects display quality.
Innovation Solution
The method involves using a liquid crystal display device with a lower substrate having scanning lines, data lines, and pixel electrodes, and an upper substrate with first and second bias electrodes. By applying direct-current and alternating-current voltages to these electrodes, the device can switch between wide and narrow viewing angles, minimizing voltage differences and preventing dark lines through polarity inversion and waveform control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a transparent conductive electrode is used for viewing angle control, then the device can switch between wide and narrow viewing angles, but the high impedance causes voltage waveform distortion and displays vertical or horizontal dark lines
Solution Approach 1:
The patent divides the transparent conductive electrode into multiple segments (first electrode strip and second electrode strip) that are insulated from each other. Each segment is independently controlled to apply voltage to specific regions of the liquid crystal layer, preventing the propagation of voltage waveform distortion across the entire electrode and eliminating the dark line defect
Solution Approach 2:
The patent applies voltage locally to specific electrode segments rather than uniformly across the entire electrode. By controlling the voltage application to particular regions (odd or even rows/columns), it addresses the viewing angle control need in specific areas while avoiding the impedance-related distortion that would affect the entire display
2Adaptability or versatility
If the viewing angle control electrode is arranged in horizontal or vertical strips, then voltage can be applied for viewing angle control, but voltage differences between strips cause entire rows or columns to appear bright or dark
Solution Approach 1:
The patent creates an asymmetric control scheme where odd and even electrode strips are controlled differently. By applying voltage to alternating strips in a staggered pattern, it prevents the symmetric propagation of voltage differences that would cause entire rows or columns to display uniformly bright or dark
Solution Approach 2:
The patent employs periodic voltage application to electrode strips, alternating between odd and even strips in a regular pattern. This periodic control ensures that voltage differences are distributed evenly across the display rather than concentrating in specific rows or columns, maintaining display uniformity
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 effectively switches between wide and narrow viewing angles, improving display quality by eliminating dark lines and enhancing the overall viewing experience.
Implementation Method 1
the liquid crystal molecules in the liquid crystal layer 13 are tilted due to the vertical electric field E (as shown by arrows in the figure)
Data Source
AI summary
A method for driving a liquid crystal display device capable of switching between a wide viewing angle and a narrow viewing angle. In a first viewing angle mode, a direct-current common voltage is applied to a common electrode and voltage signals are applied to a first bias electrode and a second bias electrode. In a second viewing angle mode, a direct-current common voltage is applied to the common electrode, a first alternating-current voltage is applied to the first bias electrode and a second alternating-current voltage is applied to the second bias electrode. In addition, in the second viewing angle mode, pixel units covered by each first electrode strip of the first bias electrode have alternating positive and negative polarities, and pixel units covered by each second electrode strip of the second bias electrode have alternating positive and negative polarities.