Liquid Crystal Display Sub-Pixel Voltage Control for Viewing Angle
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Solution Overview
Problem
Liquid crystal displays (LCDs) suffer from color and luminance distortion when viewed from different angles due to liquid crystals deflecting to a single deflection angle under a single electric potential, limiting the viewing angle for normal luminance and causing color washout.
Innovation Solution
The LCD is designed with multiple sub-pixels in each pixel area, where storage capacitors are coupled to different scan lines, allowing for varying voltage levels across sub-pixel electrodes through scan signals with multiple voltage levels, enabling liquid crystals to deflect at different angles, thus minimizing color washout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electric potential is applied to liquid crystals in each pixel, then the control of liquid crystal deflection angle is simple, but color washout occurs when viewing from different angles
Solution Approach 1:
Each pixel is divided into multiple sub-pixels (first sub-pixel, second sub-pixel, third sub-pixel, fourth sub-pixel), and each sub-pixel is controlled by a separate scan line through its own switch and storage capacitor. This segmentation allows different voltage levels to be applied to different sub-pixels, creating multiple deflection angles within a single pixel area, thereby eliminating color washout while maintaining relatively simple control architecture.
Solution Approach 2:
Different sub-pixels within the same pixel area are assigned different voltage levels through the scan signal waveform (including first, second, and third voltage levels). This creates local variations in electric field strength, causing liquid crystals in different sub-pixels to deflect at different angles. The local quality differentiation ensures that when viewed from any angle, at least one sub-pixel provides the correct color and luminance information.
2Ease of operation
If liquid crystals deflect to a single deflection angle, then the luminance control is straightforward, but color and luminance distortion occur at large viewing angles
Solution Approach 1:
The scan signal waveform is designed with multiple voltage levels (first voltage level for first sub-pixel, second voltage level for second sub-pixel, third voltage level for third and fourth sub-pixels) that dynamically adjust the electric field strength for each sub-pixel. This dynamic control allows liquid crystals in different sub-pixels to achieve different deflection angles, ensuring that color and luminance remain consistent across various viewing angles while maintaining straightforward luminance control through voltage modulation.
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 enhances the viewing angle and display performance by preventing color washout, allowing for consistent color and luminance across various viewing angles.
Implementation Method 1
liquid crystals will deflect under the influence of electric field and hence change transmission rate of light
Implementation Method 2
each of which pixels contains liquid crystals with a certain area for displaying images
Data Source
AI summary
A liquid crystal display and a driving method thereof are provided. The liquid crystal display includes a plurality of pixels, a plurality of scan lines, and a plurality of data lines. Each pixel includes a plurality of sub-pixels. Each sub-pixel is coupled to the data line, and includes a switch, a storage capacitor, and a sub-pixel electrode. The switch is coupled to a scan line to receive a scan signal. The switch is turned on by the scan signal to receive a data signal transmitted from the data line. The storage capacitors of the sub-pixels of each pixel are coupled to the scan lines, or the storage capacitor of one of the sub-pixels of each pixel is coupled to a common electrode and the storage capacitors of the other sub-pixels are coupled to the scan lines. The switch and the storage capacitor of each sub-pixel are coupled to different scan lines. The method includes transmitting the scan signal having a plurality of voltage levels to modulate the voltage levels of one or more sub-pixel electrodes of the sub-pixels of the same pixel, thereby enabling the sub-pixels of the same pixel to have different voltage levels.