Segmented Planar Loudspeaker for Wideband Directivity Control

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Solution Overview

Problem

Conventional loudspeakers face challenges in achieving a wide dispersion angle and high fidelity sound while maintaining a small form factor, as increased size leads to narrow beam-forming at higher frequencies, and multiple drive units complicate design and integration.

Innovation Solution

The implementation of an axially symmetric segmentation of a planar radiator with frequency-dependent velocity magnitude and phase, using concentric rings of electrode pairs with phase delay elements to maintain uniform surface pressure, allowing for a uniform radiation pattern across a wide range of acoustic frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the size of a loudspeaker is increased to deliver high quality sound, then maximum loudness and bass extension are improved, but narrow beam-forming occurs at higher frequencies

Engineering Contradiction:

Improvemaximum loudness and bass extensionVSAvoidbeam width at high frequencies

Core Design Contradiction:

PowerVSShape

Solution Approach 1:

The planar radiator is segmented axially symmetrically with each segmentation having frequency dependent velocity magnitude and phase control, allowing different segments to contribute differently to various frequency ranges and directions, thus maintaining wide dispersion at high frequencies while preserving bass extension capabilities

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different segments of the radiator are assigned different velocity magnitudes and phases based on their radial position, creating local variations in acoustic output that collectively produce a uniform radiation pattern across wide frequency ranges while controlling beam width

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If multiple drive units are used to achieve high fidelity sound, then frequency range coverage is improved, but device complexity increases

Engineering Contradiction:

Improvefrequency range coverageVSAvoiddesign complexity and integration difficulty

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of using multiple separate drive units, the radiator is segmented into axially symmetric sections that are electronically controlled with different velocity magnitudes and phases, achieving full frequency range coverage through a single integrated structure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The velocity magnitude and phase parameters are varied across different segments of the radiator and across frequencies, allowing a single drive unit to perform the function of multiple drive units by dynamically adjusting operational parameters

Inventive Principle:

Principle #35Parameter changes

3Volume of moving object

If the diaphragm is made finite in size for practical applications, then device compactness is improved, but edge diffraction effects produce ripples in the on-axis response and directivity pattern

Engineering Contradiction:

Improvedevice compactnessVSAvoidon-axis response uniformity

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The velocity magnitude is varied locally across different segments of the finite diaphragm, with segments closer to the edges having different velocity characteristics than center segments, compensating for edge diffraction effects and producing a uniform on-axis response

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The frequency dependent velocity distribution is designed in advance to counteract the expected edge diffraction effects, preventing ripples in the on-axis response before they occur by adjusting the velocity profile across the diaphragm surface

Inventive Principle:

Principle #9Preliminary anti-action

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 approach results in a dipole loudspeaker with a broad and smooth directivity pattern at all frequencies, reducing edge diffraction effects and enabling efficient sound reproduction with a compact design, suitable for portable devices.

Implementation Method 1

an axially symmetric segmentation of a planar radiator, where each axially symmetric segmentation has an associated frequency dependent velocity magnitude and phase but with substantially uniform surface pressure

Methodology Applied

Scientific EffectElectrostatic transduction: Electrostatics

Implementation Method 2

there are a plurality of phase delay elements such that an electric signal applied to each the electrode pairs is successively delayed from the centermost electrode pair towards an electrode pair disposed at a periphery

Methodology Applied

Scientific EffectPhase delay:

Data Source

PatentUS8831248B2Apparatus with directivity pattern

Publication Date: 2014.09.09 WSOU INVESTMENTS LLC

AI summary

A loudspeaker is described. The loudspeaker includes two or more segmentations of a planar radiator. Each of the segmentations has an associated frequency dependent velocity magnitude and phase with substantially uniform surface pressure. The two or more segmentations provide a substantially uniform radiation pattern across a wide range of acoustic frequencies. Apparatus, computer readable media and methods are also described.