Integrated Common Electrodes for Touch LCD Noise Reduction
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Solution Overview
Problem
Capacitive touch screens face issues with poor anti-interference performance, low frame rate, increased thickness, and high manufacturing complexity due to separate touch sensing and display circuitry, leading to noise interference and material inefficiencies.
Innovation Solution
The integration of common electrodes as both display and touch sensing electrodes in a two-dimensional array, with a single chip or multiple chips controlling the display and touch functions, reduces thickness, weight, and material usage while minimizing noise interference by using metal oxide or graphene for electrodes and optimizing electrode placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate touch sensing electrode layer and display electrode layer are used, then touch sensing function is achieved, but device thickness increases
Solution Approach 1:
The patent combines the touch sensing electrode layer and display electrode layer into a single integrated electrode structure. The same electrode serves dual purposes: driving the liquid crystal display and sensing touch input through capacitance changes, thereby eliminating the need for separate layers and reducing overall device thickness.
Solution Approach 2:
The electrode is designed to perform multiple functions simultaneously: it acts as both the common electrode for liquid crystal switching and the sensing electrode for touch detection. This multi-functional design allows the single electrode layer to fulfill both display and touch sensing roles without requiring additional dedicated layers.
2Reliability
If separate touch sensing circuitry and display circuitry are used, then touch sensing capability is provided, but manufacturing complexity increases
Solution Approach 1:
The patent integrates touch sensing circuitry with display circuitry by using the same electrode connections and control lines for both functions. The touch sensing readout circuitry shares the electrode interface with the display driving circuitry, reducing the number of separate components and simplifying the manufacturing process.
Solution Approach 2:
The control circuit is designed to perform dual functions: driving the liquid crystal display and reading touch sensor signals. The same control lines and electrode interfaces are used for both display operation and touch sensing, eliminating the need for separate dedicated circuitry and reducing manufacturing complexity.
3Measurement precision
If additional touch sensing layers are added, then touch sensing precision is improved, but signal-to-noise ratio deteriorates
Solution Approach 1:
The patent extracts the touch sensing function from separate additional layers and integrates it into the existing display electrode structure. By using the same electrode for both display and sensing, the design eliminates the noise and interference that would be introduced by additional separate touch sensing layers while maintaining precise touch detection capability.
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 enhances the signal-to-noise ratio, reduces manufacturing costs, and increases frame rate by eliminating the need for additional touch sensing layers and synchronizing display and touch functionality, resulting in a more efficient and cost-effective capacitive touch screen design.
Implementation Method 1
a liquid crystal layer 15 and multiple pixel units, in which the liquid crystal layer 15 and the multiple pixel units are sandwiched between the first substrate and the second substrate
Implementation Method 2
each of the multiple common electrodes is connected to the touch control circuit as a touch sensing electrode in the case that a touch sensing is performed
Data Source
Figure 1(a)~1(b)
Figure 1(c)
Figure 1(d)
AI summary
A touch display apparatus is provided. The touch display apparatus includes a display touch screen including a first substrate, a second substrate, a liquid crystal layer and multiple pixel units, the display touch screen includes multiple common electrodes arranged in a two-dimensional array; and a display touch control circuit including a display control circuit and a touch conirol circuit. The display touch control circuit is connected to the multiple common electrodes through wires in such a way that the multiple common electrodes are connected to a common level provided to the display control circuit in the case of a display is performed, and each of the multiple common electrodes is connected to the touch control circuit as a touch sensing electrode in the case of a touch sensing is performed.