Flat-Coil Loudspeaker for Hearing Devices
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Solution Overview
Problem
Dynamic speakers are not widely used in prescription hearing devices due to their large size and inefficiency compared to balanced armature receivers, necessitating improvements in loudspeakers for both prescription and non-prescription hearing devices and other body-worn audio devices.
Innovation Solution
A flat-coil loudspeaker design featuring a diaphragm separating a housing into a back and front volume, with an electrical coil assembly having a radial difference dimension greater than its thickness dimension, and opposing magnets with the same magnetic polarity, optimized for efficient sound production in a compact form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional dynamic speakers are used in hearing devices, then sound production capability is achieved, but device size becomes large and efficiency decreases
Solution Approach 1:
The patent transitions from a conventional dynamic speaker design to a flat-coil speaker design, fundamentally changing the dimensional configuration of the coil assembly. The flat-coil structure with radial difference dimension greater than thickness dimension creates a planar, two-dimensional coil layout that reduces the overall volume of the speaker while maintaining or improving efficiency. This dimensional change allows the speaker to achieve comparable efficiency to balanced armature receivers without requiring their complex multi-component structure.
Solution Approach 2:
The patent modifies key geometric parameters of the coil assembly, specifically establishing that the radial difference dimension (difference between outer and inner radii) is greater than the thickness dimension. This parameter change optimizes the magnetic field interaction and electrical characteristics, resulting in improved efficiency. Additionally, the opposing magnets are positioned with the same magnetic polarity facing each other, creating a uniform magnetic field that enhances the efficiency of the flat-coil assembly.
2Loss of energy
If balanced armature receivers are used to improve efficiency, then efficiency increases, but device complexity increases
Solution Approach 1:
The patent combines the coil assembly and diaphragm into a unified flat-coil structure where the coil is formed directly on or integrated with the diaphragm surface. This merging eliminates the need for separate voice coils, suspensions, and pole pieces required in traditional dynamic speakers and balanced armature receivers. The result is a simplified structure with fewer components that achieves comparable efficiency to balanced armature receivers while avoiding their structural complexity.
Solution Approach 2:
The patent extracts and eliminates unnecessary components from traditional speaker designs. By using a flat-coil configuration where the coil is planar and integrated with the diaphragm, the patent removes the need for complex magnetic circuits, multiple suspension systems, and deep voice coil assemblies. This extraction of essential functions into a simplified flat-coil structure reduces device complexity while maintaining efficiency.
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 flat-coil loudspeaker achieves higher efficiency across the audio band, comparable to larger dynamic speakers and balanced armature receivers, while being more compact, thus addressing size and efficiency limitations of traditional dynamic speakers.
Implementation Method 1
An electrical audio signal applied to the electrical coil assembly moves the diaphragm and the electrical coil assembly in unison in the gap between the first and second magnets
Implementation Method 2
the vibrating diaphragm and electrical coil assembly emit sound from the sound port via the front volume
Data Source
AI summary
A loudspeaker for hearing devices including a diaphragm arranged in a housing to form a back volume and a front volume acoustically coupled to a sound port is disclosed. A surface of a first magnet in the front volume faces an opposing surface of a second magnet in the back volume, and the opposing surfaces of the magnets are separated by a gap and have the same magnetic polarity. An electrical coil assembly coupled to the diaphragm has a radial difference dimension to thickness dimension ratio greater than 1, wherein the diaphragm and the electrical coil assembly are movable in the gap between the magnets in response to an electrical audio signal applied to the electrical coil assembly.