Liquid Crystal Panel Sub-Pixel Voltage Control for Brightness Uniformity
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Solution Overview
Problem
Conventional liquid crystal displays (LCDs) suffer from non-uniform brightness and color shift due to liquid crystal molecules aligning in the same direction when driven by a single external voltage, leading to noticeable brightness variations with viewing angle, which existing methods fail to adequately address without causing brightness loss or image issues like sticking and cross-talk.
Innovation Solution
The method involves dividing each unit pixel into sub-pixels with separate driving voltages, allowing liquid crystal molecules in different areas to orient differently, using a three or more-level driving method to regulate voltages and prevent uniform brightness loss, thereby reducing brightness variation across wider viewing angles without altering the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single external voltage is applied to each unit pixel, then the device complexity is low, but the brightness uniformity deteriorates due to all liquid crystal molecules aligning in the same direction
Solution Approach 1:
Each unit pixel is divided into multiple sub-pixel areas (first sub-pixel area and second sub-pixel area), with each area having independent driving circuits (first TFT, second TFT) and storage capacitors. This segmentation allows different liquid crystal regions to be controlled independently, enabling uniform brightness across the entire unit pixel while maintaining relatively simple overall device complexity.
Solution Approach 2:
Different sub-pixel areas within the same unit pixel are driven by different voltages to create locally optimized liquid crystal orientations. The first sub-pixel area uses one driving voltage while the second sub-pixel area uses another, allowing each region to contribute optimally to the overall brightness uniformity when viewed from different angles.
2Device complexity
If liquid crystal molecules are driven to align in the same direction, then the device structure is simple, but the viewing angle characteristics deteriorate causing color shift
Solution Approach 1:
The unit pixel is segmented into multiple sub-pixel areas with independent voltage control, allowing different liquid crystal regions to orient in different directions. This segmentation enables the display to maintain consistent color and brightness across a wider viewing angle range without requiring complex liquid crystal material modifications.
Solution Approach 2:
The patent applies dynamic voltage control where different sub-pixel areas receive different driving voltages that can be adjusted based on viewing conditions. This dynamic control allows the liquid crystal molecules to adapt their orientation, improving viewing angle characteristics and reducing color shift while maintaining a relatively simple device structure.
3Ease of manufacture
If conventional driving methods are used, then the manufacturing process remains simple, but image quality deteriorates due to brightness loss and image sticking
Solution Approach 1:
By dividing each unit pixel into multiple sub-pixel areas with independent driving circuits and storage capacitors, the patent achieves uniform brightness and eliminates image sticking without complicating the manufacturing process. Each sub-pixel area can be manufactured using standard TFT processes, maintaining ease of manufacture while significantly improving image quality.
Solution Approach 2:
Storage capacitors are pre-configured in each sub-pixel area to maintain driving voltages between refresh cycles. This preliminary action of voltage storage prevents brightness loss and image sticking by ensuring continuous proper voltage application to each liquid crystal region, improving reliability without adding manufacturing 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 achieves uniform brightness and reduced color shift across a wider viewing angle by allowing liquid crystal molecules to orient differently, enhancing display quality while avoiding issues like image sticking and cross-talk.
Implementation Method 1
The absolute value of the voltage difference between the pixel electrode 235 and the common electrode 231 is called a driving voltage. The driving voltage affects the arrangement of the liquid crystal molecules 241 in the liquid crystal layer 24. Hence, the tilt direction of the liquid crystal molecules 241 varies with the external voltage, so as to change the transmission and the brightness of the liquid crystal panel 20.
Data Source
AI summary
A liquid crystal panel, a liquid crystal display and a driving method are provided. The method comprises supplying different driving voltages in a plurality of areas of a unit pixel. The liquid crystal molecules in different areas receive different driving voltages to generate different arranging directions to promote the uniform brightness.