Touch Input Device Edge Support Capacitance Pressure Detection
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Solution Overview
Problem
Current touch sensor panels cannot effectively sense the magnitude of pressure applied to their surface in addition to detecting touches and their positions, limiting their functionality in computing systems.
Innovation Solution
A touch input device design featuring a first electrode and a second electrode spaced apart by a spacer layer, where the electrodes are configured to change capacitance in response to external pressure, allowing for the detection of pressure magnitude through changes in mutual capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional touch sensor panel is used, then touch position can be detected, but pressure magnitude cannot be sensed
Solution Approach 1:
The patent combines the touch sensing function and pressure detection function into a single integrated sensor structure. The first and second electrodes are positioned on opposite sides of the display, with the display itself serving as the sensing element. When pressure is applied, the display bends, changing the distance between electrodes and thus the capacitance, enabling both touch and pressure detection without separate sensor components.
Solution Approach 2:
The display serves multiple functions: it acts as both the visual output device and the pressure-sensitive sensing element. By making the display itself responsive to pressure through electrode integration, the system achieves multi-functionality where the same component performs both display and pressure detection roles, eliminating the need for additional dedicated pressure sensors.
2Measurement precision
If electrodes are placed close together for high capacitance sensitivity, then pressure detection improves, but the risk of electrical short circuit increases
Solution Approach 1:
The display acts as an intermediary dielectric layer between the first and second electrodes. This intermediary structure allows the electrodes to be positioned close together for high capacitance sensitivity while maintaining electrical insulation through the display material itself. The display's dielectric properties enable both the capacitance sensing function and electrical isolation, resolving the contradiction between sensitivity and reliability.
3Measurement precision
If the sensor structure is made more complex to detect pressure magnitude, then pressure detection capability improves, but manufacturing cost increases
Solution Approach 1:
The patent detects pressure magnitude by measuring changes in capacitance parameters resulting from display bending. Instead of using complex mechanical pressure sensors, the system utilizes electrical parameter changes (capacitance) that occur naturally when the display deforms under pressure. This approach enables pressure magnitude detection while maintaining manufacturing simplicity, as it leverages existing electrode and display structures rather than requiring additional specialized components.
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 the touch sensor panel to sense not only touches and their positions but also the magnitude of pressure applied, enhancing the functionality of touch input devices by incorporating pressure detection capabilities.
Implementation Method 1
The mutual capacitance between the first electrode and the second electrode changes according to a distance between the first electrode and the second electrode. The magnitude of the external pressure according to the change of the capacitance between the first electrode and the second electrode is detected.
Data Source
AI summary
In one embodiment, a touch input device includes a first electrode; a second electrode located on one side of the first electrode; a display disposed on one side of the first electrode opposite to the second electrode; and a spacer layer between the first electrode and the second electrode. One of the first electrode and the second electrode is a drive electrode, and the other is a receiving electrode that receives the drive signal by a mutual capacitance between the first electrode and the second electrode. When an external pressure is applied to the first electrode through the display, the first electrode is concavely bent toward the second electrode. The mutual capacitance between the electrodes changes according to a distance between the electrodes. The magnitude of the external pressure according to the change of the capacitance between the electrodes is detected.