Controlled Displacement Membrane for Digital Speakers

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Solution Overview

Problem

Existing membrane devices for digital speakers lack dynamic control over membrane displacement, leading to unreliable sound reproduction due to mechanical contact issues and fixed stop dimensions, which result in uncontrolled membrane position and vibration.

Innovation Solution

A membrane device with two actuators, where one actuator controls the membrane's movement based on its position, velocity, and acceleration, using capacitive, piezoelectric, or piezoresistive means for precise positioning and damping, integrated into the membrane structure to prevent mechanical contact and ensure dynamic control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If stops are provided to stop the membrane, then the membrane displacement is limited, but reliability problems arise due to mechanical contact

Engineering Contradiction:

Improvemembrane displacementVSAvoidreliability

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The patent replaces the mechanical stop system with a magnetic field-based control system. Magnets are positioned to create magnetic fields that exert forces on the membrane, allowing it to be stopped and positioned without physical contact. This substitution of magnetic fields for mechanical stops eliminates wear and reliability issues associated with mechanical contact while maintaining controlled displacement limits.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Length of moving object

If the dimensions of the stops are defined when the membrane is manufactured, then the stops are fixed, but they do not enable any dynamic control over the position of the membrane

Engineering Contradiction:

Improvestop dimensionsVSAvoiddynamic control

Core Design Contradiction:

Length of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic control by making the membrane position control adjustable during operation. The magnetic field strength and positioning can be varied dynamically through electrical control, allowing the membrane to be stopped at different positions as needed. This transforms the fixed, static stop system into a dynamic, adaptable control mechanism that can respond to changing operational requirements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent enables dynamic control by allowing changes in magnetic field parameters (strength, direction, positioning) during operation. By varying these parameters, the membrane's equilibrium position and stopping points can be adjusted dynamically without any physical modification to the membrane or stops, providing versatile position control.

Inventive Principle:

Principle #35Parameter changes

3Force

If one actuator applies force to move the membrane, then displacement occurs, but there is no control over the membrane position

Engineering Contradiction:

Improveactuator forceVSAvoidmembrane position control

Core Design Contradiction:

ForceVSMeasurement precision

Solution Approach 1:

The patent implements feedback control by using magnets to sense and respond to the membrane's position. The magnetic field interacts with the membrane's position to provide a restoring force that naturally limits and controls displacement. This feedback mechanism allows the system to automatically adjust the membrane position based on its current state, achieving precise control without complex additional sensors.

Inventive Principle:

Principle #23Feedback

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 enables precise control over membrane displacement, reducing secondary lobes and improving sound reproduction by eliminating uncontrolled vibrations, resulting in a more reliable and efficient digital speaker system.

Implementation Method 1

the first and second actuators are of the piezoelectric type

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the means of measuring the membrane position may be capacitive

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 3

the means of measuring the membrane position may be capacitive, piezoelectric or piezoresistive

Methodology Applied

Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentUS10003008B2Device with a controlled displacement membrane

Publication Date: 2018.06.19 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

AI summary

Membrane device comprising a support, a membrane suspended on the support, a first actuator in contact with the membrane designed to apply a force on the membrane, a second actuator in contact with the membrane designed to apply a force on the membrane, means of determining the position of the membrane relative to the support and control means of the first and second actuators, said control means applying a deformation signal to one of the first and second actuators to deform the membrane and applying a control signal to the other of the first and second actuators to control displacement of the membrane, application of the control signal being determined by the membrane position.