Polymer Speaker With Flexible Electrodes For Wide Frequency Sound
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Solution Overview
Problem
Conventional speakers using electrostrictive elements with hard electrodes face challenges in producing sufficient sound pressure, especially in low frequency regions, due to electrode interference and potential cracking, which limits their effectiveness in producing sound across a wide frequency range.
Innovation Solution
A polymer speaker design featuring a dielectric layer made of an elastomer or resin with flexible electrode layers formed from a conductive material with a low modulus of elasticity, allowing for vibration without interference and crack formation, enabling sound production across a wide frequency range without the need for an enclosure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hard electrodes are used in the electrostrictive element, then the structural integrity and conductivity are improved, but the sound pressure in low frequency region decreases and electrode cracking occurs
Solution Approach 1:
The patent changes the physical parameters of the electrode material by using a conductive polymer instead of traditional hard conductive materials. This parameter change allows the electrode to have both adequate conductivity and the flexibility needed to accommodate dielectric layer expansion and contraction without cracking or interfering with motion, thereby resolving the contradiction between structural integrity and motion interference.
Solution Approach 2:
The patent employs composite materials by creating a conductive polymer electrode that combines the conductivity of conductive materials with the flexibility of polymer matrices. This composite structure enables the electrode to maintain structural integrity while simultaneously allowing the dielectric layer to expand and contract freely, eliminating electrode cracking and motion interference.
2Stability of the object's composition
If the modulus of elasticity of the vibrating unit is increased to improve structural stability, then the primary resonance frequency increases, but the sound pressure in low frequency region decreases
Solution Approach 1:
The patent changes the elasticity parameter of the vibrating unit by using a flexible polymer dielectric layer with appropriate modulus of elasticity. This parameter optimization allows the vibrating unit to maintain structural stability while having a lower primary resonance frequency, thereby achieving good low frequency sound pressure output without sacrificing structural integrity.
3Length of moving object
If the dielectric layer thickness is reduced to make the speaker thinner, then the low frequency sound pressure increases, but the electrode may crack during expansion
Solution Approach 1:
The patent uses composite conductive polymer materials for the electrodes that can accommodate the large dimensional changes associated with thin dielectric layers. The composite structure provides both the flexibility needed for thin-layer expansion and contraction and the structural integrity to prevent cracking, enabling the speaker to be made thinner without compromising electrode reliability.
4Object-generated harmful factors
If a dynamic speaker unit is built into an enclosure to block sound from the back, then the sound cancellation problem is solved, but the device complexity and size increase
Solution Approach 1:
The patent extracts and eliminates the enclosure structure from the speaker system by using an electrostrictive element that inherently produces sound only in one direction. The flexible polymer dielectric layer expands and contracts to generate sound waves that propagate primarily in the forward direction, removing the need for enclosures and associated complexity while eliminating sound cancellation issues.
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 polymer speaker achieves increased sound pressure in both low and high frequency regions, being lightweight, thin, and cost-effective, with a flexible design that prevents electrode interference and cracking, thus expanding the reproducible frequency range.
Implementation Method 1
an electrostatic attraction between the electrodes increases, and the dielectric layer interposed between the electrodes is compressed in the thickness direction
Implementation Method 2
a polymer speaker using an electrostrictive element as a vibrating unit
Implementation Method 3
a dielectric layer made of an elastomer or a resin and a plurality of electrode layers arranged on front and back surfaces of the dielectric layer... flexible electrode layers formed from a conductive material with a low modulus of elasticity
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A polymer speaker (1) is configured to include an electrostrictive element (10) having an elastomer or resin dielectric layer (11) and a plurality of electrode layers (12a, 12b) arranged on the front and back surfaces of the dielectric layer (11). The electrode layers (12a, 12b) are formed from a conductive material including a polymer binder and a conductor and having a modulus of elasticity of 100 MPa or less. The spring constant of the electrode layers (12a, 12b) in the surface direction is smaller than the spring constant of the dielectric layer (11) in the surface direction. The volume resistivity of the electrode layers (12a, 12b) is 200 Ω·cm or less. The polymer speaker (1) provides a practical sound pressure in a wide frequency region from low frequencies to high frequencies.