Phase Plug Waveguide for Circular to Rectangular Wavefront Transformation
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Solution Overview
Problem
Existing loudspeaker phase plug designs suffer from discontinuities that cause diffraction and interference, leading to suboptimal sound quality, particularly in transforming a circular planar wavefront into a rectangular planar wavefront, often requiring multiple chambers and increasing the device length.
Innovation Solution
A phase plug design featuring a conical portion, a transitional ovoid central portion, and a wedge-shaped portion, which together form a smooth, continuous waveguide that maintains equal or varying path lengths, eliminating discontinuities and ensuring a uniform wavefront transformation from a circular to a rectangular planar wavefront.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a frusto-conical diaphragm design or spreading cone with wedge-shaped end is used to transform circular planar wavefront to rectangular planar wavefront, then wavefront transformation is achieved, but discontinuities cause diffraction and interference leading to suboptimal sound quality
Solution Approach 1:
The patent employs a curved transitional surface with elliptical cross-section that smoothly connects the conical input aperture to the rectangular output aperture. This curved geometry eliminates sharp discontinuities and angular transitions, allowing wavefronts to transform from circular to rectangular shape without causing diffraction and interference. The continuous curvature ensures uniform path lengths for all sound rays traversing the phase plug.
2Stability of the object's composition
If multiple chambers are used to achieve uniform wavefront transformation, then wavefront uniformity is improved, but device length increases
Solution Approach 1:
The patent merges the wavefront transformation function and the waveguide function into a single integrated chamber rather than using multiple separate chambers. The conical portion, transitional curved surface, and rectangular portion are combined in one continuous structure that simultaneously guides sound waves and transforms the wavefront from circular to rectangular shape, maintaining uniformity while minimizing device length.
Solution Approach 2:
The patent introduces a curved transitional surface with elliptical cross-section that operates in three-dimensional space to achieve wavefront transformation. By utilizing the third dimension (curved surface geometry) rather than extending the device length with multiple sequential chambers, the transformation is accomplished within a compact single-chamber structure.
3Object-generated harmful factors
If a smooth continuous waveguide with equal path lengths is designed, then diffraction and interference are eliminated, but manufacturing complexity increases
Solution Approach 1:
The patent divides the single chamber into three distinct functional portions: a conical portion for initial wavefront reception, a curved transitional portion with elliptical cross-section for transformation, and a rectangular portion for output. This segmentation allows each portion to be manufactured separately using standard techniques and then assembled, reducing overall manufacturing complexity while maintaining the smooth continuous geometry needed to eliminate diffraction and interference.
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 design achieves a uniform wavefront with minimal diffraction and interference, maintaining the spectral content of the input wavefront, providing improved sound quality and coherence across frequencies without the need for multiple chambers.
Implementation Method 1
the waveguide allows for the propagation of sound waves from the driver along said substantially constant or desired variant path lengths from said input aperture to所述 output aperture
Data Source
AI summary
An acoustical phase plug for use in loudspeakers produces a planar rectangular wavefront, or a wavefront with a desired amount of curvature, from the output aperture of the phase plug device when presented with a planar circular wavefront at the input aperture. The phase plug utilizes a waveguide that equalizes the travel paths from the input aperture to the output aperture. The waveguide essentially eliminates surface discontinuities thereby resulting in the reduction of diffraction of the wavefront travelling through the phase plug device.