Microphone Stacked Sensor and Circuit on Interposer
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Solution Overview
Problem
Conventional microphones face challenges in reducing their horizontal plane area and increasing the capacity of the back chamber, leading to decreased sensitivity due to the arrangement of acoustic sensors and signal processing circuits, and the use of bonding wires which can cause short-circuits and increase the microphone's height.
Innovation Solution
A microphone design featuring a supporting member with an acoustic sensor mounted above the signal processing circuit, a hollow for accommodating the circuit, and an acoustic transmission path that utilizes the space outside the sensor as the back chamber, eliminating the need for bonding wires and allowing for a smaller, more sensitive device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the acoustic sensor and signal processing circuit are arranged beside each other on the circuit board, then the electrical connection is simplified, but the plane area of the microphone increases
Solution Approach 1:
The patent transitions from a planar arrangement to a three-dimensional stacked arrangement. The acoustic sensor is positioned above the signal processing circuit through a supporting member with a hollow structure, utilizing the vertical dimension to reduce the horizontal plane area while maintaining electrical connections through the supporting member's conductive structure
2Adaptability or versatility
If bonding wires are used to connect the acoustic sensor and signal processing circuit, then the electrical connection is flexible, but the microphone height increases and short-circuit risks arise
Solution Approach 1:
The patent removes the bonding wire component from the system by implementing direct electrical connections through the supporting member's conductive structure. This extraction eliminates the height increase caused by bonding wires and removes the associated risks of wire breakage and short-circuits while maintaining electrical connectivity
Solution Approach 2:
The supporting member serves as an intermediary structure that provides both mechanical support and electrical connection functions. The hollow supporting member with conductive properties acts as a mediator between the acoustic sensor and signal processing circuit, eliminating the need for separate bonding wires
3Ease of operation
If the sound introduction port is provided in the cover, then the acoustic vibration can be introduced into the package, but the back chamber capacity decreases and sensitivity reduces
Solution Approach 1:
The patent utilizes the vertical space above the acoustic sensor by positioning the signal processing circuit in a hollow structure above the sensor. This three-dimensional arrangement allows the back chamber to extend vertically, increasing its capacity while maintaining the sound introduction port in the cover for acoustic vibration introduction
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 reduces the microphone's size and height, enhances sensitivity by increasing the back chamber capacity, and prevents short-circuits and noise interference, while maintaining effective acoustic vibration transmission.
Implementation Method 1
the supporting member is formed with an acoustic transmission path capable of transmitting an acoustic vibration between a space located outside the acoustic sensor and the supporting member and the space to serve as the back chamber inside the acoustic sensor
Data Source
AI summary
Provided is a microphone capable of reducing a plane area seen from above, and further increasing a capacity of a back chamber of an acoustic sensor. An interposer 52 is mounted on a top surface of a circuit board 43, and an acoustic sensor 51 is mounted on the top surface thereof. A signal processing circuit 53 is accommodated in a space 70 provided in the interposer 52, and mounted on the circuit board 43. The acoustic sensor 51 is connected to the circuit board 43 through a wiring structure provided in the interposer 52. The acoustic sensor 51, the interposer 52 and the like are covered by a cover 42 put on the top surface of the circuit board 43. In the cover 42, a sound introduction hole 48 is opened in a position opposed to the front chamber of the acoustic sensor 51. The interposer 52 is formed with a ventilation notch 71 for acoustically communicating a space below a diaphragm 56 of the acoustic sensor 51 with a space inside the cover 42 and outside the interposer 52.