Piezoelectric Speaker Interposed Layer for Low-Frequency Sound
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Solution Overview
Problem
Some supports to which a piezoelectric film is stuck can increase difficulty in emitting lower-frequency sound in the audible range.
Innovation Solution
Incorporating an interposed layer between the piezoelectric film and the fixing surface, which is formed of a pressure-sensitive adhesive or adhesive layer, to enhance the emission of lower-frequency sound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the piezoelectric film is stuck directly to the support, then the speaker structure is simple and easy to manufacture, but the emission of lower-frequency sound becomes difficult
Solution Approach 1:
An interposed layer is introduced between the piezoelectric film and the support as a mediator. This layer has specific physical properties (elasticity, thickness, material composition) that allow it to transmit low-frequency vibrations effectively while still providing adequate holding force, thus resolving the contradiction between simple direct attachment and effective low-frequency sound emission.
Solution Approach 2:
The physical parameters of the bonding interface are changed by introducing an interposed layer with specific elasticity, thickness, and material properties. This modifies the mechanical coupling between the piezoelectric film and support, enabling better transmission of low-frequency vibrations while maintaining adequate attachment strength.
2Reliability
If the piezoelectric film is stuck directly to the support, then the bonding is strong and stable, but the lower-frequency sound emission is hindered
Solution Approach 1:
The interposed layer acts as a mediator that maintains reliable bonding between the piezoelectric film and support while simultaneously enabling low-frequency sound emission. Its material properties and thickness are designed to provide adequate holding force without creating a rigid connection that would block vibration transmission.
Solution Approach 2:
The bonding system becomes a composite structure consisting of the piezoelectric film, interposed layer, and support. This composite approach allows optimization of each layer's properties to achieve both stable bonding and effective low-frequency vibration transmission, resolving the contradiction between bonding strength and vibration freedom.
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 interposed layer facilitates the generation of lower-frequency sound by adequately holding the piezoelectric film, allowing for stable attachment and effective sound emission regardless of the orientation of the speaker.
Implementation Method 1
a speaker employing a piezoelectric film (such a speaker hereinafter may be referred to as a piezoelectric speaker)
Implementation Method 2
an adhesive layer, and an interposed layer which is disposed between the piezoelectric film and the fixing surface
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A piezoelectric speaker (10) includes: a piezoelectric film (35); a fixing face (17) for fixing the piezoelectric film (35) to a support; and an interposed layer (40) disposed between the piezoelectric film (35) and the fixing face (17). The interposed layer (40) has a holding degree of 5 × 108 N/m3 or less.