Thin Speaker Module with Acoustic Damping Sheet
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Solution Overview
Problem
The challenge is to enhance the medium and high frequency performances and overall acoustic performance of a speaker module in a portable electronic device, where the limited thickness restricts the volume of the front acoustic cavity, leading to poor sound quality due to resonance issues.
Innovation Solution
A speaker module design incorporating a steel sheet with a recessed portion and a thin sound insulation sheet adhered to its inner side, which reduces the volume of the front acoustic cavity without affecting the sound aperture, using materials like PET, bakelite, or Acrylic, to prevent resonance and improve frequency responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the front acoustic cavity is sealed with a thin steel sheet (0.2 mm) to reduce thickness, then the module thickness is reduced, but the volume of the front acoustic cavity increases causing resonance and poor medium and high frequency performance
Solution Approach 1:
A thin sound insulation sheet (0.1-0.2mm thick) is adhered to the inner side of the steel sheet, creating a nested structure where one thin layer is placed inside another. This nested configuration allows the combination of multiple thin layers to achieve the acoustic performance of a single thick layer while maintaining the overall thin profile of the module.
Solution Approach 2:
The invention uses a composite structure consisting of a steel sheet combined with a sound insulation sheet material (such as foam, felt, or porous plastic). This composite material approach leverages the strengths of both materials: the steel sheet provides structural support and the sound insulation sheet provides acoustic damping, together achieving both thickness reduction and improved acoustic performance.
2Reliability
If the volume of the front acoustic cavity is increased to avoid resonance, then acoustic performance improves, but the module thickness increases which is not acceptable in portable devices
Solution Approach 1:
The sound insulation sheet is nested within the steel sheet structure, allowing the acoustic treatment to be embedded within the existing thin profile rather than adding external volume. This nesting enables acoustic performance improvement without increasing the overall module thickness.
Solution Approach 2:
The invention employs a thin sound insulation sheet (0.1-0.2mm) that functions as a flexible acoustic treatment layer. This thin film approach provides effective acoustic damping and resonance control while occupying minimal space, thereby improving acoustic performance without increasing module thickness.
3Reliability
If a thick steel sheet is used to seal the front acoustic cavity, then acoustic performance is improved by preventing resonance, but the module thickness increases
Solution Approach 1:
The sealing function is segmented into two separate thin components: a steel sheet for structural support and a dedicated sound insulation sheet for acoustic damping. This segmentation allows each component to be optimized for its specific function while keeping individual thicknesses minimal, achieving the combined effect of a single thick sealing layer without the thickness penalty.
Solution Approach 2:
The invention replaces a single thick steel sheet with a composite structure of thin steel sheet plus thin sound insulation sheet. This composite material solution provides the acoustic damping properties of thick material while maintaining the thin profile, as the two materials work synergistically to achieve both structural integrity and acoustic performance.
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 enhances medium and high frequency performances and overall acoustic quality while maintaining a compact thickness, ensuring stability and prolonging the module's service life without altering the existing housing mold.
Implementation Method 1
a thin sheet, which is made of a sound insulation material and is 0.1 mm to 0.2 mm thick, is adhered to the inner side of the steel sheet
Data Source
AI summary
A speaker module relates to the technical field of electroacoustic products, and comprises a lower module casing, an upper module casing and a steel sheet which are successively combined together. A speaker monomer is contained in a space enclosed by the lower module casing, the upper module casing and the steel sheet. The speaker monomer, the upper module casing and the steel sheet together enclose a front sound cavity of the module. The front sound cavity is in communication with a sound outlet hole of the module, and the sound outlet hole is located on a side part of the speaker monomer. A sheet is adhered inside the steel sheet, the thickness of the sheet being about 0.1 mm˜0.2 mm and the material of the sheet being a soundproof material.