Touch Sensor Noise Reduction via Differential Voltage Measurement
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Solution Overview
Problem
Touch sensors in display devices face sensitivity issues due to noise interference from the display panel, which affects their ability to accurately detect touch inputs.
Innovation Solution
A touch sensor design that includes a conductive layer spaced apart from the first electrode and a touch driver with a signal receiver configured to output a signal based on the voltage difference between the first and second input terminals, which helps to offset common mode noise and enhance sensitivity by using a buffer and power supply components to stabilize reference potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a touch sensor is integrated with a display panel, then the device achieves compact integration and unified manufacturing, but noise interference from the display panel degrades touch sensitivity
Solution Approach 1:
A conductive layer is introduced as an intermediary component between the display panel and the first electrode. This conductive layer serves as a mediator that helps cancel noise interference through differential voltage measurement, thereby improving touch sensitivity while maintaining the integrated structure.
Solution Approach 2:
The signal receiver measures the voltage difference between the first input terminal (connected to the first electrode) and the second input terminal (connected to the conductive layer). By establishing a reference potential through the conductive layer, the system achieves equipotentiality that cancels common-mode noise from the display panel, enhancing measurement precision.
2Measurement precision
If a conductive layer is added between the display panel and the first electrode, then noise interference is reduced and sensitivity is improved, but the device structure becomes more complex
Solution Approach 1:
The conductive layer is merged with existing display panel structures, such as being formed on the same substrate or integrated with the display driver circuitry. This combining approach minimizes the increase in device complexity while achieving noise reduction through the additional measurement reference point.
3Measurement precision
If a signal receiver with differential input terminals is used, then common mode noise is offset and sensitivity is enhanced, but the circuit complexity increases
Solution Approach 1:
The signal receiver is designed with multi-functionality, serving both as a standard voltage detection circuit and as a differential amplifier that cancels common-mode noise. By making the circuit universal, the same component performs multiple functions without proportionally increasing complexity.
Solution Approach 2:
The signal receiver changes its operating parameters by measuring voltage differences rather than absolute voltages. This parameter change from single-ended to differential measurement enables noise cancellation while using standard circuit components, thereby limiting the increase in circuit 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 solution significantly improves the sensitivity of touch sensors by reducing noise interference, allowing for more accurate detection of touch inputs and enhancing the signal-to-noise ratio.
Implementation Method 1
output a signal corresponding to a difference in voltage between the first input terminal and the second input terminal
Implementation Method 2
helps to offset common mode noise and enhance sensitivity by using a buffer and power supply components to stabilize reference potentials
Implementation Method 3
using a buffer and power supply components to stabilize reference potentials
Implementation Method 4
using a buffer and power supply components to stabilize reference potentials
Data Source
AI summary
A display device may include a display panel, a sensor unit, and a touch driver. The sensor unit is provided on the display panel and may output a sensing signal corresponding to a touch input. The sensor unit may include a first electrode and may include a conductive layer provided between the display panel and the first electrode and spaced from the first electrode. The touch driver may include a signal receiver. The signal receiver may include a first input terminal electrically coupled to the first electrode, may include a second input terminal electrically coupled to the conductive layer, may receive the sensing signal, and may output a signal corresponding to a voltage difference the first input terminal and the second input terminal.