Multilayer PCB Receiving Coil for Sealed Hearing Aid Charging
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Solution Overview
Problem
Existing hearing devices face challenges in contactless charging of secondary cells due to the need for precise alignment and close proximity of charging coils, which affects energy transfer efficiency and requires additional components for voltage conversion and charging control, making it difficult to replace batteries and maintain a sealed, moisture-tight design.
Innovation Solution
A hearing device with a battery module incorporating a receiving coil formed by a conductor track on a multi-layer circuit board, which is designed as a spiral-planar, helical coil for efficient inductive charging, and optionally includes a ferrite layer to enhance magnetic field coupling, allowing for compact and efficient energy transfer without the need for additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a receiving coil is added for contactless charging, then charging convenience is improved, but device complexity increases due to additional charging electronics and voltage conversion components
Solution Approach 1:
The receiving coil is integrated directly into the circuit board as a conductor track, merging the charging function with the existing circuit board structure. This eliminates the need for separate charging electronics and voltage conversion components, as the conductor track itself performs both signal and power functions.
Solution Approach 2:
The circuit board serves multiple functions: it provides structural support, electrical connections, and houses the receiving coil for contactless charging. The conductor track on the circuit board universally handles both data communication and power transfer, eliminating the need for dedicated charging components.
2Loss of energy
If the receiving coil is placed close to the transmitting coil for efficient energy transfer, then energy transfer efficiency is improved, but the hearing aid housing cannot maintain a sealed, moisture-tight design
Solution Approach 1:
The patent replaces the need for physical openings or removable battery compartments with contactless inductive charging. The receiving coil is integrated into the sealed housing, allowing energy transfer through electromagnetic fields without compromising the mechanical seal against moisture and environmental factors.
3Duration of action of stationary object
If conventional battery formats are replaced with secondary cells, then recharging capability is improved, but voltage conversion electronics are required increasing device complexity
Solution Approach 1:
The secondary cell is integrated directly into the circuit board structure, merging the power storage function with the circuit board. The conductor track on the circuit board provides both the electrical connections for the battery and the receiving coil for contactless charging, eliminating the need for separate voltage conversion electronics.
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 solution enables efficient and compact contactless charging with improved energy transfer efficiency, reduced manufacturing complexity, and enhanced durability by eliminating the need for precise coil alignment and additional components, while maintaining a sealed design.
Implementation Method 1
During charging, energy is transferred from the charger to the hearing aid via the coils, thus charging the secondary cell
Implementation Method 2
The circuit board also has a ferrite layer that forms a closure in the stacking direction, so that the receiving coil is arranged entirely on just one side of the ferrite layer
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A hearing device (2) is described, comprising a battery module (14), wherein the battery module (14) comprises a secondary cell (16), and wherein the battery module (14) comprises a receiving coil (18) for contactless charging of the secondary cell (16). The battery module (14) comprises a circuit board (24) with a conductor (26) forming the receiving coil (18), and wherein the circuit board (24) has several layers (30, 32), the conductor (26) extending over the several layers (30, 32) and having a conductor loop (34) with at least one turn (36) in each of the several layers (30, 32). A corresponding circuit board (24) is further described.