Conductive Pointer Electrical Connection to Touch Sensor Lower Electrode
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Solution Overview
Problem
In display devices with projected capacitive touch sensors, the capacitance changes when a conductive pointer moves below the sensor, affecting touch accuracy.
Innovation Solution
The pointer is electrically connected to the lower electrode of the touch sensor, ensuring that the capacitance remains unchanged even when the pointer is made of a conductive material by using a conductive shaft and a conductive wire to maintain electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the pointer is made of a conductive material, then the pointer can be used for analog display, but the capacitance of the touch sensor changes when the pointer moves below the sensor
Solution Approach 1:
The pointer electrode is merged with the lower electrode of the touch sensor, making them electrically connected as a single conductive structure. This allows the pointer to serve both as an analog display element and as part of the touch sensor electrode system, eliminating capacitance changes during pointer movement.
Solution Approach 2:
The lower electrode structure serves dual functions: it acts as both the pointer electrode for analog display and the lower electrode for the projected capacitive touch sensor. This multi-functional design eliminates the need for separate structures and resolves the capacitance interference problem.
2Measurement precision
If the pointer is made of an insulating material, then the capacitance remains stable, but the pointer cannot be effectively used with projected capacitive touch sensors
Solution Approach 1:
The pointer electrode and lower electrode are merged into a single conductive structure, allowing the pointer to be conductive while maintaining stable capacitance measurements by being electrically connected to the touch sensor electrode system.
3Measurement precision
If a non-conductive pointer is used, then capacitance stability is maintained, but combined analog and digital display functionality is limited
Solution Approach 1:
The lower electrode serves multiple functions simultaneously: it is the pointer electrode for analog display, the lower electrode for the touch sensor, and provides electrical connection between the pointer shaft and touch sensor circuitry. This enables full combined analog and digital functionality with stable capacitance.
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 configuration prevents changes in capacitance during pointer movement, enhancing touch accuracy and allowing for combined analog and digital displays with improved design.
Implementation Method 1
a projected capacitive touch sensor changes the capacitance when the user brings his/her finger close to the surface, and measures the ratio of the amount of current due to this change, thereby enabling to accurately determine the position of the touch
Implementation Method 2
the pointer is electrically connected to a lower electrode of the touch sensor
Data Source
AI summary
A display device according to an embodiment of the present invention includes: a display panel; a touch sensor located on the display panel; and a pointer made of a conductive material that moves on a region where the touch sensor is provided below the touch sensor; wherein the pointer is electrically connected to a lower electrode of the touch sensor.