Touch Sensor Testing via Dual Driving Signals
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Solution Overview
Problem
The accuracy of testing whether a touch detection device in a display apparatus is operating normally can vary depending on the size of the inspector's finger and the degree of adhesion, making it unreliable to test without direct contact.
Innovation Solution
A method using a touch sensor and a touch integrated circuit, where a first and second mutual capacitance are sensed by applying different driving signals to the driving electrode line, allowing for the determination of a touch operation without direct contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct touch testing is performed with a finger, then the touch detection device can be tested, but the accuracy varies depending on finger size and adhesion
Solution Approach 1:
The patent introduces a test object with a specifically designed capacitance value as an intermediary to replace direct finger touch testing. This test object serves as a standardized mediator that provides consistent capacitance characteristics, eliminating the variability introduced by different human fingers while still enabling effective testing of the touch detection device's capacitance sensing capability
Solution Approach 2:
The patent changes the testing parameter from variable human finger characteristics to a controlled test object with predetermined capacitance properties. By adjusting and standardizing the capacitance parameter of the test object, the system achieves consistent and repeatable measurement results across different testing scenarios, resolving the measurement precision issue
2Ease of operation
If different driving signals are applied to sense mutual capacitance, then touch operation can be detected without direct contact, but additional signaling complexity is introduced
Solution Approach 1:
The touch detection device's existing signal driving unit and switching circuitry are utilized to generate and apply different driving signals during testing. The system uses its own built-in resources to perform the testing function, avoiding the need for external complex testing equipment while still achieving contactless testing capability
Solution Approach 2:
The patent employs periodic switching between different driving signals (first and second driving signals with different amplitudes) to sense mutual capacitance at different states. This periodic signal application allows the system to detect touch operations by comparing capacitance values obtained under different signal conditions, achieving contactless detection through time-multiplexed signaling
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 method improves the accuracy and efficiency of testing the touch detection device by eliminating the variability caused by finger size and adhesion, allowing for reliable operation without direct contact.
Implementation Method 1
sensing a first mutual capacitance of predetermined test coordinates by applying a first driving signal to the driving electrode line and receiving a detection signal from the detection electrode line
Data Source
AI summary
A method of testing a display apparatus using a touch sensor and a touch integrated circuit is presented. The touch sensor includes a driving electrode line and a detection electrode line, and the touch integrated circuit includes a signal driving unit and a signal detection unit. The method includes sensing a first mutual capacitance of predetermined test coordinates by applying a first driving signal to the driving electrode line and receiving a detection signal from the detection electrode line, sensing a second mutual capacitance of the predetermined test coordinates by applying a second driving signal to the driving electrode line and receiving a detection signal from the detection electrode line, and determining whether a touch operation is performed based on a difference between the first mutual capacitance and the second mutual capacitance.