Touch IC Time-Division Sensing for Pen and Finger Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mutual-capacitive touch screens struggle to accurately sense small touch areas, such as pen inputs, due to minimal capacitance changes, requiring separate devices for effective detection.
Innovation Solution
A touch screen display device with a touch integrated circuit (IC) that employs a switching unit to apply different touch scan pulses in temporally divided periods, using mutual capacitance for finger touch detection and self-capacitance for pen touch detection, eliminating the need for a separate pen touch input device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mutual-capacitive touch sensing is used, then finger touch detection is effective, but pen touch detection becomes difficult due to minimal capacitance changes
Solution Approach 1:
The system dynamically switches between mutual-capacitive and self-capacitive sensing modes based on the detected touch type. During a first period, mutual-capacitive mode is used for finger touch detection, and during a second period, self-capacitive mode is used for pen touch detection, allowing the system to adapt its sensing mechanism to different input devices
Solution Approach 2:
The touch sensing operation is divided into periodic time slots: a first period dedicated to mutual-capacitive sensing for finger touches, and a second period dedicated to self-capacitive sensing for pen touches. This periodic switching enables the system to handle different touch types sequentially without requiring separate hardware for each input method
2Adaptability or versatility
If separate pen touch input device is added, then pen touch detection capability is improved, but device complexity increases
Solution Approach 1:
The existing touch screen electrodes are designed to perform multiple functions: during the first period they operate in mutual-capacitive mode for finger touch detection, and during the second period they operate in self-capacitive mode for pen touch detection. This multi-functionality eliminates the need for separate pen touch input devices while maintaining detection capability for both finger and pen inputs
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
Enables accurate sensing of both finger and pen touches without additional hardware, enhancing accuracy and reducing the size of the touch sensing unit for pen detection.
Implementation Method 1
The mutual-capacitive touch screens supply a driving voltage to a touch driving electrode to allow a mutual capacitance to be generated between the touch driving electrode and a touch sensing electrode, and measure a change (which is caused by a touch) in the mutual capacitance to determine whether there is the touch
Data Source
AI summary
A touch screen display device includes a display panel, a touch screen panel disposed on the display panel, and configured to include a plurality of first electrodes, which are parallelly arranged in a first direction, and a plurality of second electrodes which are parallelly arranged in a second direction, a switching unit configured to apply a first touch scan pulse to the plurality of first electrodes during a first period, and apply a second touch scan pulse to the plurality of first and second electrodes during a second period, a first touch sensing unit configured to apply the first touch scan pulse to the switching unit, and a second touch sensing unit configured to apply the second touch scan pulse to the switching unit.