Bone Conduction Speaker with Compound Vibration Device
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Solution Overview
Problem
Current bone conduction speakers suffer from limited tone quality due to resonance peaks in either low or high frequency areas, resulting in abrupt frequency responses and feeble sounds, which are difficult to improve with existing vibration devices.
Innovation Solution
A compound vibration device comprising a vibration conductive plate and a vibration board, where the plate is fixed with a magnetic system and a voice coil, allowing for adjustable resonance peaks to achieve a flatter, wider frequency response by staggering rods at 60-degree angles and using materials like stainless steel for the conductive plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single vibration device is used in bone conduction speakers, then the structure is simple, but the frequency response is abrupt with resonance peaks causing poor tone quality
Solution Approach 1:
The vibration device is divided into two independent vibration boards (first and second vibration boards) with different resonance characteristics. Each board has its own resonance peak at different frequency ranges, and when combined, they create a composite frequency response that is flatter and covers a wider range, avoiding the abrupt resonance peaks of a single vibration device.
2Stability of the object's composition
If the vibration board is fixed rigidly to improve structural stability, then the structure is stable, but the tone quality deteriorates due to resonance peaks
Solution Approach 1:
The rigid connection is segmented into two separate vibration boards that are independently connected to the housing. This segmentation allows each board to maintain its own vibration characteristics while collectively providing structural stability, thereby improving tone quality by avoiding concentrated resonance peaks.
Solution Approach 2:
The invention uses a composite vibration system consisting of two different vibration boards with distinct material or structural properties. This composite approach combines the advantages of both boards to achieve both structural stability and improved tone quality with reduced resonance peaks.
3Power
If resonance peaks are enhanced to increase sound intensity, then the sound is louder, but the frequency response becomes abrupt and tone quality worsens
Solution Approach 1:
The sound intensity is distributed across two vibration boards with resonance peaks at different frequencies. This segmentation prevents concentration of energy at a single frequency, thereby maintaining loud sound output while achieving a flatter overall frequency response and improved tone quality.
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 provides a bone conduction speaker with a flatter frequency response, avoiding abrupt frequency responses and feeble sounds, thereby enhancing tone quality and broadening the range of perceivable frequencies, making it more suitable for human hearing.
Implementation Method 1
the plate is fixed with a magnetic system and a voice coil
Implementation Method 2
the vibration in the ear drum drives our auditory nerves, makes us feel the acoustic vibrations. However, the current bone conduction speakers are transferring vibrations through our skin, subcutaneous tissues and bones to our auditory nerves
Data Source
AI summary
The present invention relates to a bone conduction speaker and its compound vibration device. The compound vibration device comprises a vibration conductive plate and a vibration board, the vibration conductive plate is set to be the first torus, where at least two first rods inside it converge to its center; the vibration board is set as the second torus, where at least two second rods inside it converge to its center. The vibration conductive plate is fixed with the vibration board; the first torus is fixed on a magnetic system, and the second torus comprises a fixed voice coil, which is driven by the magnetic system. The bone conduction speaker in the present invention and its compound vibration device adopt the fixed vibration conductive plate and vibration board, making the technique simpler with a lower cost; because the two adjustable parts in the compound vibration device can adjust both low frequency and high frequency area, the frequency response obtained is flatter and the sound is broader.