Liquid Crystal Display Subpixel Switching Timing for Parasitic Capacitance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In liquid crystal display devices using the in-pixel selector driving method, parasitic capacitance causes uneven coupling conditions between subpixels, leading to color imbalance due to differences in parasitic capacitance coupling levels, especially when the last second switching element turns off at the same time as the first switching element, resulting in a two-fold greater coupling level for the subpixel written last.
Innovation Solution
The liquid crystal display device configures the second switching elements to turn off before the first switching element, ensuring that the last second switching element turns off first, thereby maintaining consistent coupling conditions across all subpixels during the OFF period, which helps in balancing the color output by compensating for parasitic capacitance effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the last second switching element turns OFF at the same time as the first switching element to maximize the ON period utilization, then the writing efficiency is improved, but the parasitic capacitance coupling level becomes two-fold greater for the subpixel written last, causing color imbalance
Solution Approach 1:
The patent applies preliminary action by having the last second switching element turn OFF before the first switching element, rather than at the same time. This anticipates the parasitic capacitance coupling issue and prevents it before it occurs, ensuring uniform coupling conditions across all subpixels while maintaining efficient writing through proper timing coordination.
2Duration of action of moving object
If the second switching elements turn OFF at the same time as the first switching element, then the ON period is fully utilized for writing, but the coupling condition becomes uneven across subpixels, leading to color unbalance
Solution Approach 1:
The patent applies local quality by differentiating the turn-OFF timing for the last second switching element compared to other second switching elements. Specifically, the last second switching element turns OFF at a different time (before) than the first switching element, creating a localized timing adjustment that ensures uniform parasitic capacitance coupling conditions across all subpixels while maintaining overall writing efficiency.
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 configuration ensures that the condition affecting subpixels due to parasitic capacitance is the same for all subpixels, thereby maintaining color balance and preventing unbalanced color outputs, even when the signal potential is written last.
Implementation Method 1
a parasitic capacitance is normally present between the control electrode of a switching element and a wire
Implementation Method 2
the signal potential in the capacitive elements changes slightly due to parasitic capacitance coupling (capacitive coupling)
Data Source
AI summary
The present disclosure provides a liquid crystal display device including: for each pixel, a first switching element provided in common for a plurality of subpixels making up a pixel, the first switching element having its one end connected to a signal line; for each pixel, a plurality of second switching elements one provided for each subpixel, each of the plurality of second switching elements being connected between the pixel electrode of one of the plurality of subpixels and the other end of the first switching element; and a drive section adapted to turn ON and OFF the plurality of second switching elements in sequence during the ON period of the first switching element and turn OFF the second switching element that turns ON last in sequence first, and then turn OFF the first switching element.