Door Handle Case Sealing for Water-Resistant Touch Detection
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Solution Overview
Problem
Existing door handle apparatuses with integrated electrostatic sensors are prone to false positive detections due to water intrusion between the inner and outer cases, which can cause capacitance changes mimicking hand contact, and increasing the sealing member thickness to address this issue risks increasing the apparatus size and introducing defects.
Innovation Solution
A door handle apparatus design featuring a substrate with electrodes, a cover, and a sealing member where the locking electrode is positioned above the sealing member, ensuring a sufficient distance to minimize capacitance interference, and using a double-sided tape to secure the cover to the outer case, preventing water ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the sealing member is increased to prevent water intrusion, then false positive detections are reduced, but the overall size of the door handle apparatus increases and defects such as sink marks, voids, and warpage are introduced
Solution Approach 1:
The sealing structure is divided into two functional parts: the first sealing member (thickness t1) that provides structural support and the second sealing member (thickness t2) that provides water protection. This segmentation allows each part to be optimized independently, preventing water intrusion without requiring excessive overall thickness that would cause defects.
Solution Approach 2:
Instead of increasing thickness in the vertical dimension, the patent positions the electrostatic sensor in the horizontal dimension (on the inner case) and uses a waterproof seal in the gap between inner and outer cases. This dimensional repositioning achieves water protection without increasing the critical thickness dimension.
2Object-affected harmful factors
If the thickness of the sealing member is increased to ensure sufficient distance from water accumulation areas, then water intrusion is prevented, but manufacturing defects increase
Solution Approach 1:
The sealing function is segmented between the first sealing member (structural role) and the second sealing member (waterproof role). The second sealing member is specifically positioned to seal the gap between inner and outer cases, providing water protection with controlled thickness that avoids manufacturing defects.
Solution Approach 2:
The second sealing member acts as an intermediary element specifically positioned in the water-prone gap between inner and outer cases. This targeted placement provides water protection without requiring excessive thickness throughout the entire sealing member, thereby avoiding defects like sink marks and warpage.
3Reliability
If the sealing member thickness is increased to prevent water accumulation near electrodes, then false positive detections are eliminated, but the apparatus size increases
Solution Approach 1:
The electrostatic sensor is repositioned from a centralized location to the inner case surface, utilizing the horizontal dimension. The waterproof seal is placed in the vertical gap between inner and outer cases. This dimensional redistribution eliminates the need for increased thickness while maintaining both detection accuracy and water protection.
Solution Approach 2:
The sealing function is segmented into structural sealing (first sealing member) and waterproof sealing (second sealing member in the gap). This allows the apparatus to maintain compact size while providing sufficient protection near the electrodes to prevent false positive detections.
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
The design effectively mitigates or eliminates false positive detections by minimizing capacitance interference and water intrusion, while maintaining a compact size and avoiding defects like sink marks and warpage.
Implementation Method 1
a sealing member formed by injecting a potting agent into the first accommodating recessed part, the sealing member covering and sealing the substrate and the first electrode within the first accommodating recessed part
Implementation Method 2
water intrusion occurring between the inner and outer cases may result in unwanted water retention within a gap between a door handle case's inner surface and a sealing member thereof. Such water retention causes a capacitance change equivalent to that triggered by a hand approaching the door handle apparatus
Data Source
AI summary
Door-handle apparatus includes substrate, first-electrode provided on first-surface of the substrate or inside the substrate, second-electrode facing a second-surface of the substrate opposite the first-surface, door-handle case having inner and outer cases, the inner case having first-accommodating-recessed part configured to accommodate the substrate, the outer case being provided so as to cover first-opening part of the first-accommodating-recessed part of the inner-case, cover provided on the second-surface of the substrate, and including both second-opening part facing the second-surface and second-accommodating-recessed part that communicates with the second-opening part and is recessed in a direction away from the second-surface, the second-electrode being provided on innermost-end face of the second-accommodating-recessed part or in innermost-end wall of the second-accommodating-recessed part, and sealing member formed by injecting potting-agent into the first-accommodating-recessed part, the sealing member covering and sealing the substrate and the first-electrode within the first-accommodating-recessed part while leaving exterior-surface of the innermost-end wall exposed.