Acceleration Sensor Embedment Electrodes Miniaturization

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Solution Overview

Problem

Conventional acceleration sensors face challenges in reducing size due to the space required for electrode units, which occupy about 30% to 40% of the sensor chip area, making it difficult to miniaturize the device.

Innovation Solution

The acceleration sensor integrates embedment electrodes within the fixed plate, serving as both fixed and detection electrodes, eliminating the need for separate electrode units and allowing for a more compact design by arranging them along the thickness direction of the plate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate electrode units are used for fixed electrodes and detection electrodes, then the sensor can detect capacitance changes accurately, but the sensor size increases due to occupying 30% to 40% of the sensor chip area

Engineering Contradiction:

Improvecapacitance detection accuracyVSAvoidsensor chip area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent combines the functions of fixed electrodes and detection electrodes into a single electrode unit. The fixed electrode and detection electrode are integrated as one component, eliminating the need for separate electrode units and reducing the area occupied on the sensor chip while maintaining capacitance detection capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The electrode unit is designed to serve multiple functions simultaneously - it acts as both a fixed electrode for capacitance formation and a detection electrode for measuring capacitance changes. This multi-functional design eliminates redundant components and reduces overall sensor size

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If multiple separate electrode units are provided for fixed electrodes and detection electrodes, then the detection function is maintained, but the manufacturing process becomes more complex

Engineering Contradiction:

Improvedetection functionVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the fixed electrode and detection electrode into a single integrated electrode unit, reducing the number of components that need to be manufactured and assembled. This simplification directly reduces manufacturing process complexity while maintaining the necessary detection functionality

Inventive Principle:

Principle #5Merging (Combining)

3Ease of operation

If electrode units are arranged in the plane of the sensor chip, then the sensor can function properly, but the sensor size is increased

Engineering Contradiction:

Improvesensor functionalityVSAvoidsensor chip area

Core Design Contradiction:

Ease of operationVSArea of stationary object

Solution Approach 1:

The patent transitions from planar arrangement of electrodes to a three-dimensional configuration where the electrode extends in the thickness direction of the fixed plate. This vertical arrangement instead of horizontal placement significantly reduces the area occupied on the sensor chip surface while maintaining proper electrode functionality

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 configuration enables a reduction in sensor size by eliminating the need for additional electrode units, simplifying the manufacturing process, and enhancing detection capabilities while maintaining accurate acceleration measurement.

Implementation Method 1

detection electrodes electrically connected to the first fixed electrode and the second fixed electrode to detect a capacitance between the movable electrode and the first fixed electrode and the second fixed electrode, the acceleration sensor being configured to detect acceleration based on a change in the capacitance

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS9052334B2Acceleration sensor

Publication Date: 2015.06.09 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

In an acceleration sensor, a sensor unit includes a weight portion having a recess section with one open surface and a solid section one-piece formed with the recess section, beam portions for rotatably supporting the weight portion such that the recess section and the solid section are arranged along a rotation direction, a movable electrode, fixed electrodes, detection electrodes electrically connected to the fixed electrodes to detect a capacitance between the movable electrode and the fixed electrodes. A fixed plate is arranged in a spaced-apart relationship with a surface of the weight portion on which the movable electrode is provided, and embedment electrodes are embedded in the fixed plate to extend along a thickness direction of the fixed plate, the embedment electrodes having one end portions facing the movable electrode to serve as the fixed electrodes and the other end portions configured to serve as the detection electrodes.