TN Display Panel with Bridged Touch Electrodes for Capacitance Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid crystal display panels with touch control functions in twisted nematic (TN) mode face challenges as the capacitance change incurred by touch is shielded by the liquid crystal capacitance generated during display, making touch sensing structures inapplicable.
Innovation Solution
A display panel design with electrodes on two opposite sides of a liquid crystal layer, utilizing spacers and bridge pads to enable reliable touch control by connecting touch signal lines to electrode patterns on a second substrate, while using an electric field for display driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If capacitance change sensing is used for touch control in TN mode, then touch sensing capability is improved, but the sensing accuracy deteriorates because liquid crystal capacitance shields the touch-induced capacitance change
Solution Approach 1:
The patent segments the electrode structure into separate touch sensing electrodes and display electrodes. The touch sensing electrodes are positioned on one substrate while display electrodes are on the opposite substrate, allowing independent optimization of touch sensing and display functions without mutual interference.
Solution Approach 2:
The patent introduces a transparent conductive oxide (TCO) layer as an intermediary between the touch sensing electrodes and the liquid crystal layer. This TCO layer allows the touch sensing electrodes to detect capacitance changes without being shielded by the liquid crystal capacitance, while still enabling the liquid crystal layer to function properly for display.
2Illumination intensity
If electrodes are disposed on two opposite sides of liquid crystal layer for display driving, then display quality is improved, but touch control implementation becomes more complex
Solution Approach 1:
The patent designs the electrode structure on the second substrate to serve dual purposes: the electrode patterns function both as display electrodes for generating the electric field and as touch sensing electrodes for detecting user input. This multi-functionality reduces the overall device complexity despite having electrodes on both substrates.
Solution Approach 2:
The patent embeds the touch sensing functionality within the existing electrode structure on the second substrate. The touch sensing electrodes are integrated into the same layer and structure as the display electrodes, with the TCO layer nesting the touch sensing capability within the broader electrode system.
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
Enables reliable touch control functionality alongside display driving by ensuring the capacitance change is not shielded by the liquid crystal capacitance, allowing for effective touch sensing in TN mode.
Implementation Method 1
An electric field generated when the pixel electrode on the first substrate and the electrode pattern on the second substrate are energized is used to drive the liquid crystal layer for display
Implementation Method 2
a liquid crystal layer disposed between the first substrate and the second substrate
Implementation Method 3
the location is detected by sensing the capacitance change between each set of pixel electrode and common electrode on the same substrate
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A display panel (10, 10A, 20), including a first substrate (101), a second substrate (102), a liquid crystal layer (LCL), data lines (DL), scan lines (SL), touch signal lines (TL), pixel structures (PX, PX-A), bridge pads (BP, BP-A), electrode patterns (EP), and first spacers (SP1). The liquid crystal layer (LCL) is disposed between the first substrate (101) and the second substrate (102). The bridge pads (BP, BP-A) are disposed on the first substrate (101) and are electrically connected to the touch signal lines (TL) respectively. The electrode patterns (EP) are respectively arranged on the second substrate (102) at intervals along a first direction (D1) and a second direction (D2), and overlap the pixel electrodes (PE, PE-A) of the pixel structures (PX, PX-A). The first spacers (SP1) are disposed on the second substrate (102) and respectively abut on the bridge pads (BP, BP-A) along a stacking direction (D3) of the first substrate (101) and the second substrate (102). Each of the electrode patterns (EP) covers one of the first spacers (SP1) to be electrically connected to one of the bridge pads (BP, BP-A).