Liquid Crystal Display Branch Electrode Capacitance Balancing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display devices experience flickers due to changes in pixel sizes for different colors, leading to imbalanced capacitance and voltage shifts, which affect image quality and chromaticity.
Innovation Solution
A liquid crystal display device design that maintains storage capacitance (Cstg) at a constant value across pixels of varying sizes by using branch electrodes that extend over neighboring pixels and are covered with a light blocking film, ensuring the second capacitance falls within 90% to 110% of the first capacitance, thereby stabilizing voltage shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pixel sizes are changed for every color to adjust chromaticity, then screen hue can be corrected, but capacitance becomes imbalanced causing flickers and voltage shifts
Solution Approach 1:
The patent changes the capacitance parameter by introducing branch electrodes that extend over neighboring pixels. This increases the storage capacitance of smaller pixels to balance it with larger pixels, preventing voltage shifts and flickers while maintaining the desired chromaticity adjustment through pixel size differences
Solution Approach 2:
The branch electrode acts as an intermediary element between pixels of different sizes. By extending from smaller pixels to overlap with neighboring pixels, it mediates the capacitance imbalance without requiring equal pixel sizes, thus enabling chromaticity correction while maintaining image stability
2Reliability
If storage capacitance is increased for smaller pixels to balance capacitance, then flickers are prevented, but pixel transmissivity may be altered affecting image quality
Solution Approach 1:
The patent uses a light blocking film as a temporary or sacrificial element that is formed over the branch electrode. This film blocks light in the specific region where the branch electrode extends, compensating for any transmissivity changes without requiring permanent structural modifications to the pixel electrode itself
Solution Approach 2:
The light blocking film is applied locally only in the region where the branch electrode extends over neighboring pixels. This localized approach ensures that capacitance balancing is achieved without uniformly affecting the entire pixel area, thus preserving overall pixel transmissivity and image quality while preventing flickers
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 solution effectively prevents flickers and maintains image quality by setting storage capacitances to a predetermined range, allowing for chromaticity adjustments without altering pixel transmissivity, thus enhancing display stability and reducing manufacturing costs.
Implementation Method 1
an image is formed by controlling transmissivity of light of the pixel for every pixel by changing the behavior of the liquid crystal molecules
Implementation Method 2
Cstg is capacitance (storage capacitance) generated between a counter electrode (or capacitive electrode) and the pixel electrode
Data Source
AI summary
A liquid crystal display device includes a first substrate on which pixels having a thin film transistor are formed in regions surrounded by scanning lines and video signal lines, a second substrate which faces the first substrate and having color filters and light blocking films formed thereon, and a liquid crystal layer which is sandwiched between the first substrate and the second substrate. The thin film transistor has a gate electrode connected to the scanning line, a drain electrode connected to the video signal line and a source electrode connected to a pixel electrode. The pixels include first pixels having a first width and second pixels having a second width smaller than the first width. The pixel electrode of the second pixel has a branch electrode extending from the pixel electrode with at least a portion of the branch electrode overlapping the video signal line or the scanning line.