Piezoelectric Sensor Amplification Adjustment via Writable Memory

Solution Overview

Problem

Existing piezoelectric sensors face challenges in maintaining consistent measurement sensitivity due to variations in charge signals generated from piezoelectric element crystals, leading to difficulties in accurately adjusting the amplification factor during the sensor assembly process, which results in increased production costs and potential inaccuracies in the finished product.

Innovation Solution

A piezoelectric sensor design that incorporates a writable memory within a single integrated circuit to store information for setting the amplification factor, allowing for precise adjustment of the amplification factor in the finished product, with a separate writing terminal for data input, enabling high-accuracy adjustments without exposing the circuit board and reducing production complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional piezoelectric sensor structure is used, then the manufacturing process is simple, but the sensor is highly sensitive to external vibrations and noise

Engineering Contradiction:

Improvesensor stabilityVSAvoidsensor structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The piezoelectric element is nested within a housing that contains damping material, creating a nested structure where the damping material is positioned between the piezoelectric element and the housing walls. This nested configuration allows the damping material to surround and protect the piezoelectric element from external vibrations while maintaining a compact overall structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The sensor incorporates multiple materials with different properties: a piezoelectric element for sensing, a damping material for vibration reduction, and a housing for structural support. This composite material approach combines the advantages of each material to achieve both sensitivity and stability.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the piezoelectric element is exposed directly to the environment, then the sensor response is fast, but the element is vulnerable to mechanical damage and environmental factors

Engineering Contradiction:

Improveelement protectionVSAvoidsignal response time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The piezoelectric element is nested within a housing that contains damping material, creating a nested structure where the damping material is positioned between the piezoelectric element and the housing walls. This nested configuration allows the damping material to surround and protect the piezoelectric element from external vibrations while maintaining a compact overall structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The damping material is applied locally around the piezoelectric element rather than throughout the entire sensor, providing protection only where needed. The housing provides additional localized protection at critical points while leaving the piezoelectric element's sensing surfaces exposed for rapid response.

Inventive Principle:

Principle #3Local quality

3Reliability

If damping material is added to reduce vibrations, then the sensor stability improves, but the manufacturing process becomes more complex

Engineering Contradiction:

Improvevibration resistanceVSAvoidassembly process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The piezoelectric element is nested within a housing that contains damping material, creating a nested structure where the damping material is positioned between the piezoelectric element and the housing walls. This nested configuration allows the damping material to surround and protect the piezoelectric element from external vibrations while maintaining a compact overall structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The damping material is applied as a thin layer or coating around the piezoelectric element rather than as a thick separate component. This thin-film approach reduces the number of assembly steps and simplifies manufacturing while still providing effective vibration damping.

Inventive Principle:

Principle #30Flexible shells and thin films

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 accurate and efficient adjustment of the amplification factor in the finished product, reducing production costs and ensuring consistent measurement sensitivity, while maintaining a compact circuit design.

Implementation Method 1

a piezoelectric element (1) having a first surface and a second surface opposite to each other

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3435052B1Piezoelectric sensor

Publication Date: 2023.01.04 CITIZEN FINEDEVICE CO LTD

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AI summary

In piezoelectric sensors, conventional amplification factor adjustment methods involving the cutting of a wiring pattern or use of a laser trimmable resistor are unable to adjust the amplification factor when the sensor is in a completed state. As a result, the production process becomes complex and production costs increase. Further, because the amplification factor adjustment is carried out in a different state from that of the finished product, the problem that the amplification factor is not set correctly in the finished product also occurs. A non-volatile memory 111 is incorporated in an integrated circuit 110 in which are integrated piezoelectric sensor circuit elements. The amplification factor is adjusted by writing data from a writing terminal 114 to change an amplification resistor a107.