Active-Matrix Sonic Transducer Pixels Without Wafer Bonding
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Solution Overview
Problem
Current micromachined ultrasonic transducers (MUTs) are based on passive matrices and are costly to fabricate due to wafer bonding, limiting the realization of large-area production and integration with external circuits.
Innovation Solution
An electronic device with multiple transducer pixels, each comprising a sonic transducer, a demultiplexer, a driving line, a switching line, and a reading line, where the driving line provides a driving signal to emit sonic waves, and the switching line controls the demultiplexer to output sensing signals, integrated on a substrate with a fabrication method that includes forming layers and etching a sacrificial layer before adding a piezoelectric layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wafer bonding is used to integrate MUT with external circuits, then integration is achieved, but manufacturing cost increases and large-area fabrication becomes difficult
Solution Approach 1:
The patent merges the MUT array and external circuits onto a single substrate, eliminating the need for wafer bonding. The substrate integrates both the transducer elements and the readout electronics, enabling large-area fabrication while maintaining integration functionality.
Solution Approach 2:
The substrate serves multiple functions: it acts as the structural base for the MUT array, provides electrical connections for external circuits, and enables large-area fabrication. This multi-functional approach replaces the traditional separate components that required wafer bonding.
2Ease of manufacture
If passive matrix configuration is used for MUT, then fabrication is simplified, but three-dimensional array images cannot be realized
Solution Approach 1:
The patent segments the substrate into multiple independently controllable transducer elements arranged in an array. Each element can be individually addressed and controlled, enabling three-dimensional array imaging while maintaining fabrication simplicity through standardized element design.
Solution Approach 2:
The patent transitions from a two-dimensional passive matrix configuration to a three-dimensional array structure by adding spatial dimensionality to the transducer element arrangement. This enables volumetric imaging capabilities while preserving the fabrication advantages of planar processing.
3Stability of the object's composition
If sacrificial layer is etched after forming piezoelectric layer, then structural integrity is maintained, but fabrication complexity increases
Solution Approach 1:
The patent performs the etching of the sacrificial layer before forming the piezoelectric layer. This preliminary action simplifies the fabrication process by eliminating subsequent etching steps, while the structural integrity is maintained through the sequential layer formation that ensures proper mechanical support is in place before adding the piezoelectric material.
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
Enables cost-effective large-area production of MUTs by integrating them on a substrate with an active matrix, reducing fabrication costs and enabling applications such as distance detection, fingerprint biometrics, gesture detection, and ultrasonic imaging.
Implementation Method 1
forming a piezoelectric layer on the sacrificial layer
Data Source
AI summary
An electronic device is provided. The electronic device includes multiple transducer pixels. Each of the transducer pixels includes a sonic transducer, a demultiplexer electrically connected to the sonic transducer, a driving line electrically connected to the sonic transducer, a switching line electrically connected to the demultiplexer, and a reading line electrically connected to the demultiplexer. The driving line is used to provide a driving signal to the sonic transducer to emit sonic waves. The switching line is used to turn on the demultiplexer to output the sensing signal received by the sonic transducer to the reading line.