Shielding Sheet for In-Cell Touch Display Signal Accuracy
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Solution Overview
Problem
In in-cell touch display devices, coupling capacitance between wires and touch sensing electrodes reduces the accuracy of touch sensing signals due to interference, affecting the performance of the touch sensing system.
Innovation Solution
A shielding sheet made of conductive material, such as metal or indium tin oxide (ITO), is introduced above the connecting wires between the touch IC pins and sensing electrodes to reduce capacity coupling, improving signal accuracy by grounding or applying a constant voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wires are used to connect second touch sensing electrodes to touch IC pins, then electrical connection is achieved, but coupling capacitance is generated that reduces touch sensing accuracy
Solution Approach 1:
A shielding sheet is introduced as an intermediary component between the wires and the first touch sensing electrodes. This shielding sheet acts as a mediator that blocks the capacitive coupling interference from reaching the sensitive touch sensing electrodes, thereby protecting the touch sensing accuracy while maintaining the necessary electrical connections.
Solution Approach 2:
The patent converts the harmful capacitive coupling effect into a beneficial shielding effect by grounding the shielding sheet. By intentionally creating a controlled capacitive path to ground, the harmful interference is redirected away from the touch sensing electrodes, transforming the harmful coupling capacitance into a protective shielding mechanism.
2Measurement precision
If a shielding sheet is added to reduce coupling capacitance, then touch sensing accuracy is improved, but device complexity increases
Solution Approach 1:
The shielding sheet is designed to serve multiple functions simultaneously: it provides capacitive shielding to block interference, acts as an electrical connection pathway through its contact with wires and IC pins, and can be integrated into existing device layers. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
Solution Approach 2:
The shielding sheet is merged with existing device components rather than being added as a completely separate element. It is positioned to work in conjunction with the wires and IC pins already present in the device, combining shielding functionality with existing structural elements to minimize 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
The shielding sheet effectively minimizes capacitive coupling, enhancing the accuracy and reliability of touch sensing signals by isolating the connecting wires from the touch IC pins, thereby improving the overall performance of the touch display device.
Implementation Method 1
a coupling capacitance is generated between the wires of the second touch sensing electrodes and the first pins of the first touch sensing electrodes
Implementation Method 2
A shielding sheet made of conductive material, such as metal or indium tin oxide (ITO), is introduced above the connecting wires between the touch IC pins and sensing electrodes to reduce capacity coupling
Data Source
AI summary
A touch display device includes a first substrate, a second substrate, a number of first sensing electrodes formed on the first substrate, a number of second sensing electrodes formed on the second substrate, a touch integrated circuit set on the first substrate, and a number of connecting wires formed on the first substrate. The touch integrated circuit includes a number of first pins correspondingly connected to the first sensing electrodes and a number of second pins correspondingly connected to the second sensing electrodes. The connecting wires correspondingly connect two opposite terminals of the first sensing electrodes with two opposite ends of the first pins. A part of connecting wires are arranged between the first pins and the second pins. The first substrate includes a shielding sheet formed in the first substrate and located above the part of the connecting wires arranged between the first pins and the second pins.