Touch Input Device LGM Disturbance Detection
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Solution Overview
Problem
Touch input devices, such as smartphones, face challenges in accurately detecting touch signals and recognizing multiple touches when affected by low ground mass (LGM), leading to signal disruptions and incorrect touch recognition.
Innovation Solution
A touch input device with a touch sensor that includes a plurality of electrodes, a drive unit for applying driving signals, a touch signal detection unit for detecting touch-position-related signals, and an LGM disturbance signal detection unit for detecting LGM-disturbance-signal-related signals, which allows for the inhibition of LGM disturbance signals from the touch-position-related signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a touch sensor uses a single layer or double layer electrode structure, then the device structure is simple and manufacturing is easy, but the touch signal detection accuracy deteriorates when affected by low ground mass (LGM)
Solution Approach 1:
The touch sensor divides the electrode structure into multiple independent layers (first electrode layer, second electrode layer, third electrode layer) with different functions. The first and third layers serve as driving electrodes while the second layer serves as receiving electrodes, allowing separate optimization of each layer's function to improve touch signal detection accuracy while maintaining manufacturing feasibility
Solution Approach 2:
The patent transitions from a single-layer or double-layer planar structure to a multi-layer three-dimensional electrode configuration. By stacking electrode layers at different heights and positions, the system captures touch signals from multiple spatial dimensions, improving detection accuracy without significantly complicating the manufacturing process
2Ease of operation
If the touch input device is in a floating state without being held, then the user can manipulate the device conveniently, but low ground mass (LGM) interference occurs causing signal disruption and incorrect touch recognition
Solution Approach 1:
The patent introduces a ground electrode layer as an intermediary component between the signal electrodes and the external environment. This ground layer acts as a shield that blocks LGM interference from affecting the touch signals, allowing the device to maintain reliable operation in floating state without requiring the user to hold the device
Solution Approach 2:
The patent converts the harmful LGM interference into a beneficial shielding effect by strategically placing ground electrodes. The ground electrodes create a reference potential that actually protects the signal electrodes from LGM noise, transforming the interference problem into a solution that enhances touch signal reliability in floating operation mode
3Measurement precision
If multiple electrodes are used to detect touch positions, then the touch position detection capability is improved, but the complexity of signal processing and distinguishing LGM disturbance signals increases
Solution Approach 1:
The patent segments the electrode system into functionally distinct layers: driving electrodes in the first and third layers, and receiving electrodes in the second layer. This segmentation allows the control unit to process signals from each layer independently and systematically, reducing the complexity of distinguishing LGM disturbance signals from actual touch signals while maintaining high touch position detection precision
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 enables accurate detection of touch signals and recognition of multiple touches even in a floating state, similar to a gripped state, thereby improving touch sensitivity and reliability.
Implementation Method 1
the LGM-disturbance-signal-related signal may include information about capacitance that reduces the amount of change in mutual capacitance generated by coupling between the object and at least some of the plurality of electrodes
Data Source
AI summary
Disclosed is a touch input device including: a touch sensor including a plurality of electrodes; a drive unit configured to apply a driving signal to at least some of the plurality of electrodes of the touch sensor; a touch signal detection unit configured to detect a touch-position-related signal related to a touch position of an object inputted to the touch surface from at least some of the plurality of electrodes of the touch sensor; and an LGM disturbance signal detection unit configured to detect an LGM-disturbance-signal-related signal related to an LGM disturbance signal generated from the touch surface from at least some of the plurality of electrodes of the touch sensor.