Acoustic Transducer Solid Film Layer for Uniform Thickness
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Solution Overview
Problem
Typical acoustic transducers using liquid or paste type polymers face issues with uneven distribution on varying surface topographies and limited vibrating displacement due to fully filled polymers, which restrict performance.
Innovation Solution
The acoustic transducer design includes a substrate with a back chamber and a piezoelectric unit, featuring a slit and opening, with an additional film layer formed by rolling or hot pressing, allowing the piezoelectric unit to vibrate with maximum displacement and lowest restriction, and ensuring uniform thickness distribution for improved structural reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If liquid or paste type polymers are used to create an additional film layer using spin-coating method, then the polymer fills the accessible spaces on patterned structure, but the materials may not distribute evenly on different surface topographies and fully filled polymers limit vibrating displacement
Solution Approach 1:
The patent changes the physical state of the polymer from liquid/paste to solid thin film, and changes the deposition method from spin-coating to vacuum deposition. This parameter change enables uniform thickness distribution across different surface topographies while avoiding the filling issue that limits vibrating displacement.
2Quantity of substance
If fully filled polymers are used in the additional film layer, then the accessible spaces are completely filled, but the vibrating displacement is limited and performance is restricted
Solution Approach 1:
The patent changes the polymer deposition method from liquid/paste filling to solid thin film deposition. This creates a uniform additional film layer that does not completely fill the patterned structure, thereby maintaining the piezoelectric element's vibrating displacement capability while still providing the desired additional film function.
3Ease of manufacture
If spin-coating method is used to form additional film layer, then the process is simple, but the thickness distribution is non-uniform on varying surface topographies
Solution Approach 1:
The patent replaces the mechanical spin-coating process with a vacuum deposition process. This substitution eliminates the centrifugal force distribution issue that causes non-uniform thickness in spin-coating, achieving uniform film deposition even on varying surface topographies.
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 enhances the Sound Pressure Level (SPL) and structural reliability of acoustic transducers by allowing maximum piezoelectric unit displacement with minimal restriction, suitable for larger area transducers.
Implementation Method 1
a piezoelectric unit formed on the second oxide layer and including a first electrode layer, a piezoelectric layer and a second electrode layer sequentially stacked from bottom to top
Data Source
AI summary
An acoustic transducer includes: substrate including first silicon layer, first oxide layer and second silicon layer, back chamber is formed therethrough; second oxide layer on the substrate; piezoelectric unit on the second oxide layer and including first electrode layer, piezoelectric layer and second electrode layer; slit and opening formed in the second electrode layer; metal pad stacked on the first electrode layer at the opening; and additional film layer including first and second parts, the first part is lay on the second electrode layer and covers the slit, and the second part is lay on the metal pad, through slot is formed penetrating the second part to expose the metal pad. Compared with the related art, additional film layer is formed by vapor deposition, and the piezoelectric unit can vibrate with maximum displacement and lowest restriction, thereby effectively improving SPL and structural reliability, which is suitable for larger acoustic transducers.