Piezoelectric Column Array in Anodic Oxide Film for Noise Attenuation
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Solution Overview
Problem
Conventional methods for manufacturing piezoelectric columns in electronic devices face challenges such as inefficient sound wave attenuation, poor filling of piezoelectric material due to air pressure, and complexity in forming densely packed vertical holes, leading to reduced precision and durability.
Innovation Solution
The use of an anodic oxide film with regularly arranged through holes and pores to embed piezoelectric columns, which are filled using vacuum pressure and rapid thermal annealing, along with conductive columns to connect electrodes, simplifies the manufacturing process and enhances recognition precision and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If synthetic resin, polymer, or epoxy is used as the peripheral portion material, then the piezoelectric columns are supported, but the efficiency of attenuating sound waves is insufficient
Solution Approach 1:
The patent uses a composite structure combining a porous body (peripheral portion) made of synthetic resin, polymer, or epoxy with piezoelectric columns. The porous structure provides both mechanical support for the piezoelectric columns and effective sound wave attenuation through its void architecture, resolving the contradiction between support capability and noise reduction efficiency.
Solution Approach 2:
The peripheral portion is designed as a porous body with controlled porosity. The porous structure enables effective attenuation of sound waves propagating from piezoelectric column side surfaces while maintaining structural integrity and support functionality. The pores scatter and absorb acoustic energy, significantly improving noise reduction compared to solid materials.
2Manufacturing precision
If holes are formed in a synthetic resin mold or polymer mold to densely form piezoelectric columns, then the precision is improved, but it is difficult to form vertical holes densely
Solution Approach 1:
The patent forms through holes extending completely through the mold before filling with piezoelectric material. This preliminary action of creating complete through-holes eliminates the difficulty of forming dense vertical holes in closed-bottom molds, as the holes provide direct pathways for material filling and allow precise positioning of piezoelectric columns in dense arrangements.
Solution Approach 2:
Instead of forming holes from the top surface only (closed-bottom approach), the patent inverts the approach by forming through-holes that extend completely through the mold thickness. This inversion enables easier formation of dense vertical hole patterns and simplifies the filling process, directly addressing the manufacturing difficulty.
3Manufacturing precision
If piezoelectric material is charged into holes with closed bottom, then the holes are filled, but poor filling occurs due to air pressure within the mold
Solution Approach 1:
The patent inverts the hole structure from closed-bottom to through-hole configuration. This inversion eliminates air trapping issues during material filling, as the through-holes allow air to escape freely during the filling process. The piezoelectric material can be charged into the through-holes without poor filling caused by air pressure, simplifying the overall process.
Solution Approach 2:
The patent extracts the air entrapment problem by creating through-holes that extend completely through the mold. This structural modification allows air to be expelled during the filling process, eliminating the air pressure issue that causes poor filling. The solution extracts the harmful air pockets from the system while maintaining the filling process.
4Manufacturing precision
If a semiconductor substrate is used to form holes and then replaced with insulating member, then the holes can be formed precisely, but the process becomes complicated and performance deteriorates if substrate is not completely removed
Solution Approach 1:
The patent extracts the semiconductor substrate from the final device structure, using it only temporarily for hole formation if needed. The substrate is completely removed and replaced with an insulating member that provides both structural support and electrical insulation. This extraction eliminates the complexity of substrate replacement while ensuring complete removal, as the insulating member is integrated directly into the final device architecture.
Solution Approach 2:
The insulating member serves multiple functions: it provides structural support for the piezoelectric columns, acts as an electrical insulator between electrodes, and serves as the final mold material. This multi-functionality replaces the need for separate semiconductor substrate and insulating member, simplifying the overall process while maintaining manufacturing precision.
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 allows for high recognition precision and improved durability of piezoelectric material-based electronic devices by effectively attenuating noise and preventing thermal deformation, while simplifying the manufacturing process and enabling miniaturization.
Implementation Method 1
the anodic oxide film surrounds the piezoelectric column and attenuates sound waves propagating from the side surface of the piezoelectric column
Implementation Method 2
a voltage is applied across electrodes provided respectively on the upper surface and the lower surface of a piezoelectric column made of a piezoelectric material to vibrate the piezoelectric column up and down to generate a measurement signal
Implementation Method 3
the return signal is detected to measure an electric potential attributable to deformation of the piezoelectric column
Data Source
AI summary
Disclosed are a piezoelectric material-based electronic device having high recognition precision for a three-dimensional shape and improved durability, and a manufacturing method thereof. The electronic device includes an anodic oxide film, a first electrode provided on an upper surface of the anodic oxide film, a second electrode provided on an a lower surface of the anodic oxide film, and a piezoelectric column made of a piezoelectric material and provided between the first electrode and the second electrode.