Speaker Sensor Positioning for Distortion Correction
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Solution Overview
Problem
Existing speaker systems face challenges in precisely correcting sound distortion and varying sound quality due to the limitations of using Hall elements for feedback control, which struggle to efficiently detect the movement of the voice coil and bobbin, leading to potential damage and inefficient assembly.
Innovation Solution
A speaker design that includes a magnetic sensor secured to a moving magnet on the vibrating unit, positioned within a space surrounded by the bobbin, allowing for precise detection of the magnetic flux changes and enabling high-precision feedback control by using a composite vector of driving and moving magnetic fluxes, thus avoiding interference from the magnetic circuit and damper member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Hall element is used as a magnetic sensor to detect effective magnetic flux density changes, then the speaker size is prevented from excessively increasing and power consumption is reduced, but the movement of the voice coil and bobbin cannot be directly detected, making it difficult to highly precisely correct sound distortion
Solution Approach 1:
The patent introduces a moving magnet as an intermediary element attached to the vibrating unit. This moving magnet generates a magnetic flux that interacts with the stationary magnetic sensor, enabling indirect detection of the voice coil and bobbin movement with high precision. The intermediary magnet bridges the gap between the moving components and the stationary sensor, solving the detection precision problem without requiring direct contact or complex sensor installation.
2Measurement precision
If the Hall element is embedded in the surface of the plate facing the voice coil, then the structure is compact, but the Hall element cannot fully detect a change in the effective magnetic flux density and the vibrating diaphragm and damper member may hit the Hall element
Solution Approach 1:
The patent inverts the traditional sensor arrangement by placing the magnetic sensor on the opposite side of where the Hall element would normally be positioned. Instead of embedding the sensor in the plate surface facing the voice coil, the magnetic sensor is positioned to detect the magnetic flux from the moving magnet, which is attached to the vibrating unit. This inversion allows the sensor to detect magnetic flux changes without being in the path of the vibrating diaphragm and damper member, eliminating the collision risk while maintaining detection precision.
3Reliability
If feedback control is implemented using a Hall element to detect effective magnetic flux density, then distortion in the driving current can be corrected, but the complex installation structure of the Hall element reduces assembly efficiency
Solution Approach 1:
The patent segments the detection system into two independent parts: a moving magnet attached to the vibrating unit and a stationary magnetic sensor fixed to the frame. This segmentation allows each component to be manufactured and positioned separately, simplifying the assembly process. The moving magnet can be easily attached to the vibrating unit, while the magnetic sensor can be independently mounted on the frame, eliminating the complex embedding process required for Hall elements and significantly improving assembly efficiency while maintaining feedback control accuracy.
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 design allows for highly precise detection and correction of sound distortion, preventing damage to the diaphragm and allowing for increased amplitude and improved sound output without obstructing the magnetic flux, ensuring efficient assembly and operation.
Implementation Method 1
a magnetic sensor configured to detect a magnetic flux generated from the moving magnet
Implementation Method 2
a voice coil secured to the bobbin and a magnetic circuit unit configured to form a magnetic flux travelling across the voice coil
Data Source
AI summary
A vibrating unit includes a diaphragm and a bobbin, and a voice coil is secured to the bobbin. A detecting unit includes a moving magnet and a magnetic sensor. The magnetic sensor is disposed in a space surrounded by the bobbin, whereas the moving magnet is secured to an outer surface of the bobbin. Therefore, even when the moving magnet and a damper member move backward significantly, the magnetic sensor is prevented from being hit by the moving magnet and the damper member.