Moisture Sensor Attaching Members Resin Parasitic Capacitance
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Solution Overview
Problem
Intraoral moisture measuring devices face challenges in achieving high measurement accuracy due to noise from parasitic capacitance caused by capacitive coupling between the substrate and attaching members, which affects the calculation of moisture content, especially in dry oral cavities where minute changes in biological information are measured.
Innovation Solution
The design includes a biosensor, processing unit, and attaching members where the total area of overlap regions between the attaching members and the substrate is smaller than the sensor area of the biosensor, with the attaching members made of resin and engagement claws, and a substrate configuration that reduces capacitive coupling, enhancing noise suppression and measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If attaching members are used to secure the substrate to the housing, then structural stability is improved, but parasitic capacitance increases due to capacitive coupling between the attaching members and substrate
Solution Approach 1:
The harmful capacitive coupling effect is extracted and eliminated by using resin attaching members instead of conductive attaching members. The resin material inherently prevents capacitive coupling between the substrate and housing, thereby removing the source of parasitic capacitance while maintaining structural attachment functionality.
Solution Approach 2:
The material parameter of the attaching members is changed from conductive materials to resin materials. This parameter change fundamentally alters the electrical characteristics of the attaching members, transforming them from sources of capacitive coupling to electrically isolated components, thus eliminating parasitic capacitance generation.
2Object-generated harmful factors
If the overlap area between attaching members and substrate is reduced, then parasitic capacitance is reduced, but attachment strength may be compromised
Solution Approach 1:
The material parameter is changed from conductive to resin material, which allows for reduced overlap area without compromising attachment strength. The resin material provides both mechanical attachment functionality and electrical isolation, enabling a design where smaller overlap areas suffice for both structural and electrical requirements.
Solution Approach 2:
The use of resin attaching members represents a composite material solution that combines mechanical attachment properties with electrical isolation properties. This composite functionality allows the attaching members to provide both structural support and parasitic capacitance reduction simultaneously, even with reduced overlap areas.
3Ease of manufacture
If conventional attaching members are used, then manufacturing is simplified, but measurement accuracy deteriorates due to noise from parasitic capacitance
Solution Approach 1:
The material parameter of attaching members is changed to resin, which inherently provides electrical isolation properties. This parameter change eliminates parasitic capacitance without complicating the manufacturing process, as resin attaching members can be integrated into existing manufacturing workflows while significantly improving measurement accuracy.
Solution Approach 2:
The resin material's electrical insulation property, which might seem like a limitation for structural attachment, is converted into a beneficial feature that eliminates parasitic capacitance. This transforms a potential disadvantage into an advantage, improving measurement accuracy while maintaining manufacturing simplicity.
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 improves the accuracy of moisture measurement by reducing parasitic capacitance and noise, leading to more reliable calculations of moisture content in the oral cavity.
Implementation Method 1
noise from parasitic capacitance caused by capacitive coupling between the substrate and attaching members
Data Source
AI summary
A moisture measuring device includes a biosensor, a processing unit, a substrate, a housing, and one or more attaching members. The biosensor has a sensor surface for acquisition of biological information. The processing unit is configured to process the biological information acquired by the biosensor. The substrate has a first principal surface on which the processing unit is mounted. The housing accommodates the biosensor, the processing unit, and the substrate. The one or more attaching members are disposed on the first principal surface side of the substrate to attach the substrate to the housing. The total area of one or more overlap regions in which the one or more attaching members overlap the substrate in the first principal surface of the substrate when viewed in a direction perpendicular to the first principal surface of the substrate is smaller than a sensor area of the sensor surface of the biosensor.