Piezoelectric Speaker Surface Structure for Wide Frequency Response
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Solution Overview
Problem
Conventional speakers in electronic devices, especially in mobile devices, face challenges in achieving optimal sound pressure and frequency response due to size constraints and the suppression of natural vibrational modes when using a single electric deformable plate element across the entire surface.
Innovation Solution
A speaker design utilizing piezoelectric deformable plate elements placed in strategic locations, such as corners of a rigid planar surface structure, to excite multiple natural vibrational modes, with band-pass filters for specific frequency selectivity, allowing for wide frequency response and sufficient sound pressure across the audio range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electric deformable plate element is used across the entire surface, then the device structure is simple, but the natural vibrational modes are suppressed and frequency response is limited
Solution Approach 1:
The speaker surface is divided into multiple segments, each with its own deformable plate element. The surface is segmented into zones (e.g., corner elements, edge elements, center elements) that can independently excite different vibrational modes, allowing simultaneous activation of multiple natural modes without the limitations of a single monolithic element.
Solution Approach 2:
Different regions of the speaker surface are equipped with deformable plate elements having different characteristics optimized for their local function. Corner elements may have different size, shape, or material properties compared to center elements, allowing each local region to contribute optimally to specific frequency ranges and vibrational modes.
2Strength
If the surface structure is made rigid for structural stability, then structural integrity is improved, but the ability to generate sufficient sound pressure is reduced
Solution Approach 1:
The rigid surface structure is transformed into an acoustic radiator through controlled mechanical vibration. Deformable plate elements are attached to the rigid surface and driven to vibrate at resonant frequencies, causing the entire surface structure to oscillate and radiate sound. This allows the surface to maintain its structural rigidity while simultaneously functioning as an efficient acoustic source.
Solution Approach 2:
The physical state of the surface structure is changed by introducing controlled vibrations through deformable plate elements. By varying vibration frequency, amplitude, and spatial distribution across multiple elements, the system can generate sufficient sound pressure while maintaining overall structural integrity through the rigid framework.
3Volume of moving object
If device size is reduced for mobile applications, then portability is improved, but speaker performance and audio quality deteriorate
Solution Approach 1:
The surface structure serves multiple functions simultaneously: it provides the device's structural housing, acts as the speaker diaphragm for audio output, and can be controlled to produce different vibrational modes for enhanced acoustic performance. This multi-functionality eliminates the need for separate dedicated speaker components, reducing overall device size while maintaining audio quality.
Solution Approach 2:
The speaker system utilizes the two-dimensional surface area of the device body as the acoustic radiating element, rather than relying on a traditional three-dimensional speaker enclosure. By exciting multiple vibrational modes across the surface, the system achieves enhanced audio performance from a thin, planar structure, enabling high-quality audio in space-constrained mobile devices.
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 effectively utilizes multiple vibrational modes to achieve a wide frequency response of large magnitude and sufficient sound pressure across the audio frequency range, enhancing audio quality without suppressing natural modes.
Implementation Method 1
A speaker design utilizing piezoelectric deformable plate elements placed in strategic locations, such as corners of a rigid planar surface structure, to excite multiple natural vibrational modes
Implementation Method 2
piezoelectric deformable plate elements placed in strategic locations, such as corners of a rigid planar surface structure, to excite multiple natural vibrational modes
Data Source
Figure 1
Figure 2A~2D
Figure 2E~3
AI summary
According to one aspect, there is provided a speaker comprising a body, a surface structure rigidly attached to the body, electro-magnetic deformable plate elements attached to the rigid planar surface structure and configured to bend, when driven with voltage or current source, the surface structure, and electro-magnetic deformable plate element specific band-pass filter for at least one electro-magnetic deformable plate element of the electro-magnetic deformable plate elements, the band-pass filter having at least one electro-magnetic deformable plate element specific pass band.