Temperature-Compensated Electrode Sheet for Accurate Touch Pressure Sensing
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Solution Overview
Problem
Current touch input devices are unable to accurately detect pressure magnitude on touch surfaces, as they are not temperature-compensated, leading to inaccuracies in pressure detection due to environmental temperature changes.
Innovation Solution
A temperature-compensated electrode sheet is introduced, featuring a pressure electrode and a reference pressure electrode, where the distance between these electrodes changes with applied pressure, allowing for capacitance detection and calculation of pressure magnitude based on the difference between reference and detected capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a touch input device uses a simple electrode structure for touch position detection, then the device is easy to manufacture and operate, but it cannot accurately detect pressure magnitude due to lack of temperature compensation
Solution Approach 1:
The electrode structure is segmented into multiple functional components: a first electrode, a second electrode, and a reference electrode. Each electrode serves a specific function in the capacitance measurement process, allowing the system to differentiate between temperature-induced capacitance changes and pressure-induced capacitance changes, thereby achieving accurate pressure detection without requiring complex external compensation systems
Solution Approach 2:
The reference electrode acts as an intermediary element that provides a baseline capacitance measurement unaffected by pressure. By comparing the capacitance change between the first/second electrodes (which are pressure-sensitive) and the reference electrode, the system can isolate and measure only the pressure-related capacitance changes, achieving accurate pressure detection while maintaining a relatively simple overall structure
2Ease of manufacture
If the electrode sheet structure is simplified for ease of manufacture, then production cost decreases, but temperature variations cause inaccuracies in pressure detection
Solution Approach 1:
The invention utilizes changes in capacitance parameters in response to different physical stimuli. The first and second electrodes exhibit capacitance changes due to both temperature and pressure, while the reference electrode exhibits capacitance changes only due to temperature. By measuring and comparing these capacitance parameter changes, the system can mathematically isolate the pressure component, achieving reliable pressure sensing under varying temperature conditions while maintaining a simple, manufacturable electrode sheet structure
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 solution enables accurate detection of pressure magnitude on touch surfaces, compensating for temperature variations and improving the reliability of pressure sensing in touch input devices.
Implementation Method 1
A capacitance detected at the pressure electrode is changed according to the distance change
Implementation Method 2
A capacitance detected at the reference pressure electrode is changed according to the distance change
Data Source
AI summary
An electrode sheet disposed in a touch input device capable of detecting a pressure of a touch on a touch surface may be provided. The touch input device includes: a display module; a pressure electrode disposed under the display module; and a reference pressure electrode disposed under the display module. A distance between the pressure electrode and a reference potential layer is changed when the pressure is applied to the touch surface. A capacitance detected at the pressure electrode is changed according to the distance change. A magnitude of the pressure applied to the touch surface is calculated on the basis of a difference between a reference capacitance calculated from a capacitance detected at the reference pressure electrode and a detected capacitance calculated from the capacitance detected at the pressure electrode.