Liquid Crystal Panel Touch Sensor Electrode Layout
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Solution Overview
Problem
Existing touch panels with pressure detection capabilities suffer from interface reflection issues due to air layers, which degrade display quality.
Innovation Solution
A liquid crystal panel design with touch drive electrodes on one substrate and pressing detection electrodes on the other, with a liquid crystal layer in between, allowing for touch and pressure detection without an air layer, thus preventing interface reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a space part (air layer) is provided between the pressure detection plate and the ground plate, then pressing detection is enabled, but interface reflection occurs which impairs display quality
Solution Approach 1:
The patent introduces the liquid crystal layer as an intermediary substance between the pressure detection plate and the ground plate, replacing the air layer. This mediator eliminates interface reflection while preserving the electrostatic capacitance detection mechanism, as the liquid crystal layer maintains the necessary electrical insulation and mechanical flexibility for accurate pressing detection.
Solution Approach 2:
The patent changes the physical parameter of the medium between the electrodes from gas (air) to liquid crystal. This parameter change eliminates the optical reflection issue while maintaining the electrical properties needed for capacitance-based pressure detection, as liquid crystal has different optical and electrical characteristics compared to air.
2Adaptability or versatility
If additional electrodes for pressing detection are added, then touch position and pressing can be detected, but device complexity increases
Solution Approach 1:
The patent makes the liquid crystal layer serve multiple functions: it acts as both the display medium and the dielectric layer for pressure detection. The same liquid crystal layer that enables display functionality also serves as the intermediary for electrostatic capacitance-based pressing detection, eliminating the need for separate structural components.
Solution Approach 2:
The patent merges the display function and the pressure detection function into a single integrated structure. The liquid crystal layer simultaneously fulfills both roles, combining what would traditionally be separate functional layers into one multi-functional component, thereby reducing overall device 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
Enables accurate detection of touch positions and pressures without impairing display quality, maintaining the thickness of standard liquid crystal panels without pressure detection functionality.
Implementation Method 1
detects amounts of change in electrostatic capacitances generated between the touch drive electrodes and the pressing detection electrode, thereby detecting pressing when touched
Data Source
AI summary
A liquid crystal panel capable of sensing a touch includes a TFT substrate 1; a CF substrate 2 arranged so as to be opposed to the TFT substrate 1; a liquid crystal layer 3 interposed between the TFT substrate 1 and the CF substrate 2; touch drive electrodes Tx arranged on a liquid crystal layer 3 side of the CF substrate 2; touch detection electrodes Rx arranged on a side of the CF substrate 2 opposite to the liquid crystal layer 3; a pressing detection electrode Fx arranged on a liquid crystal layer 3 side of the TFT substrate 1; and a control unit that supplies a driving signal to the touch drive electrodes Tx and detects detection signals output from the touch detection electrodes Rx, thereby detecting a touch position, and that detects amounts of change in electrostatic capacitances generated between the touch drive electrodes Tx and the pressing detection electrode Fx, thereby detecting pressing when touched.