Differential Capacitive Sensing Layout for Temperature-Stable Detection
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Solution Overview
Problem
Capacitive sensors used in human-computer interaction are affected by temperature, leading to inaccurate detection results.
Innovation Solution
A capacitance detection apparatus with a sensing module comprising two opposing sensing units on either side of a substrate, where one sensing unit is electrically connected to a differential detection circuit through a connecting circuit, allowing for the elimination of temperature influence by comparing capacitance changes between the two units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If capacitive sensors are used for human-computer interaction, then ease of installation and low cost are achieved, but detection accuracy deteriorates due to temperature influence
Solution Approach 1:
The sensing structure is divided into two separate sensing units (first sensing unit and second sensing unit) located on opposite sides of a substrate. Each unit independently detects capacitance changes, allowing the system to segment the temperature effect from the target detection effect through differential measurement.
Solution Approach 2:
A substrate is introduced as an intermediary element between the two sensing units. This substrate allows the sensing units to be positioned on opposite sides while maintaining electrical isolation and enabling differential detection of capacitance changes caused by temperature versus those caused by detection objects.
2Ease of manufacture
If capacitive sensors are used for human-computer interaction, then ease of installation and low cost are achieved, but detection accuracy deteriorates due to temperature influence
Solution Approach 1:
The sensing structure is divided into two separate sensing units (first sensing unit and second sensing unit) located on opposite sides of a substrate. Each unit independently detects capacitance changes, allowing the system to segment the temperature effect from the target detection effect through differential measurement.
Solution Approach 2:
A substrate is introduced as an intermediary element between the two sensing units. This substrate allows the sensing units to be positioned on opposite sides while maintaining electrical isolation and enabling differential detection of capacitance changes caused by temperature versus those caused by detection objects.
3Measurement precision
If temperature influence is eliminated through differential detection, then detection accuracy is improved, but device complexity increases due to additional sensing units and circuits
Solution Approach 1:
The first sensing unit and second sensing unit are merged into a single integrated sensing module with a shared substrate and connecting circuit. This merging approach allows differential detection to be implemented while reducing overall structural complexity compared to using two completely separate sensor assemblies.
Solution Approach 2:
The substrate serves multiple functions: it provides mechanical support for both sensing units, acts as an electrical insulator, and enables the differential detection configuration. This multi-functionality reduces the need for additional components and simplifies the overall device 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
Improves detection accuracy by isolating temperature effects from changes caused by detection objects, enhancing the reliability of capacitance detection.
Implementation Method 1
a differential detection circuit for detecting changes in capacitance of the sensing module; the first sensing unit and the second sensing unit are electrically connected to the differential detection circuit through the connecting circuit
Data Source
Figure 1~3a
Figure 3b~5
Figure 6~7
AI summary
A capacitance detection apparatus and an electronic device are disclosed. The capacitance detection apparatus (10) includes: a sensing module (11), a connecting circuit (12), and a differential detection circuit (13) for detecting changes in capacitance of the sensing module (11); the sensing module (11) comprises: a substrate (111), and a first sensing layer (112) and a second sensing layer (113) respectively located on two sides of the substrate (111); a first sensing unit (1121) of the first sensing layer (112) is opposite to a second sensing unit (1131) on the second sensing layer (113), and the first sensing unit (1121) covers the second sensing unit (1131); the first sensing unit (1121) and the second sensing unit (1131) are electrically connected to the differential detection circuit (13) through the connecting circuit (12), respectively. When a detection object approaches the capacitance detection apparatus (10), the capacitance of the first sensing unit (1121) is influenced by the temperature and the detection object, and the capacitance of the second sensing unit (1131) is only influenced by the temperature. Through the capacitances of the first sensing unit (1121) and the second sensing unit (1131), the influence of temperature can be eliminated, the changes in capacitance caused by the detection object can be determined, and the detection accuracy of the capacitance detection apparatus (10) can be improved.