Dual Membrane Receiver Unit for Enhanced Low-Frequency Response
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Solution Overview
Problem
Miniature receiver units, such as those in hearing aid instruments, face limitations in frequency response due to limited membrane area and stroke length, particularly in low-frequency response, which is exacerbated by space constraints in devices like receiver-in-canal (RIC) hearing aids.
Innovation Solution
A balanced armature type receiver unit with two moveable membranes, where the moving armature is mechanically connected to both membranes via stiff and resonating elements, allowing each membrane to resonate at different frequencies, enhancing the overall frequency response without increasing the unit's outer dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the membrane area or stroke length is increased to improve low-frequency response, then the low-frequency response is enhanced, but the outer dimensions of the receiver unit increase
Solution Approach 1:
The receiver unit is divided into multiple independent membrane elements (first membrane, second membrane, etc.) that can be driven by a common moving armature. Each membrane segment contributes to different frequency ranges, with the overall frequency response being the sum of individual membrane responses. This segmentation allows enhanced low-frequency response without increasing the overall receiver dimensions.
Solution Approach 2:
Multiple membranes are arranged in a nested or stacked configuration where they share the same spatial envelope. The membranes are positioned at different locations along the acoustic path, with each membrane having its own suspension and drive mechanism. This nesting approach allows multiple functional elements to occupy overlapping or adjacent spaces, achieving enhanced frequency response within compact dimensions.
2Volume of moving object
If a single membrane is used in a miniature receiver unit, then the outer dimensions remain small, but the low-frequency response is weak due to limited membrane area and stroke length
Solution Approach 1:
The receiver unit is divided into multiple independent membrane elements (first membrane, second membrane, etc.) that can be driven by a common moving armature. Each membrane segment contributes to different frequency ranges, with the overall frequency response being the sum of individual membrane responses. This segmentation allows enhanced low-frequency response without increasing the overall receiver dimensions.
Solution Approach 2:
Multiple membranes are combined in a stacked or nested arrangement, sharing a common moving armature and magnetic circuit structure. The membranes are acoustically coupled to produce combined output, with their individual frequency responses adding together to create an enhanced overall response. This merging approach achieves improved low-frequency performance while maintaining compact dimensions through shared structural elements.
3Reliability
If multiple membranes are added to enhance frequency response, then the frequency response is improved, but the device complexity increases
Solution Approach 1:
A single moving armature structure serves multiple functions by simultaneously driving multiple membranes. The magnetic circuit and suspension system are designed to accommodate and drive several membranes in unison, allowing one actuator to control multiple functional elements. This multi-functionality reduces the number of separate drive mechanisms needed, thereby limiting the increase in device complexity.
Solution Approach 2:
Multiple membranes are combined in a stacked or nested arrangement, sharing a common moving armature and magnetic circuit structure. The membranes are acoustically coupled to produce combined output, with their individual frequency responses adding together to create an enhanced overall response. This merging approach achieves improved low-frequency performance while maintaining compact dimensions through shared structural elements.
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 dual membrane configuration significantly enhances low-frequency response by up to 10 dB, improving the overall audio output while maintaining comparable high-frequency response, suitable for space-constrained applications like RIC hearing aids.
Implementation Method 1
a moving armature type motor (103) which is mechanically connected to the first and second moveable membranes
Implementation Method 2
The resonating elements may involve a string element, such as an extension spring
Data Source
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AI summary
The present invention relates to a receiver unit comprising a plurality of moveable membranes, a motor assembly being adapted to drive a first moveable membrane and one or more successive moveable membranes in accordance with an incoming electrical drive signal, wherein the first and successive membranes are adapted to enhance the frequency response of the receiver unit. The present invention further relates to a hearing aid instrument comprising the receiver unit.