Physical Quantity Sensor With Zoned Gaps and Elastic Stoppers

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Solution Overview

Problem

Existing physical quantity sensors face challenges in achieving both high sensitivity and impact resistance while minimizing damping, as previous designs either have uniform thickness and through-hole depth, leading to excessive damping, or fixed gap distances that limit sensitivity enhancement.

Innovation Solution

The sensor design includes a movable body with a first region and a second region relative to the rotation axis, featuring different gap distances and through-hole groups, along with elastic portions at stopper overlap positions, allowing for reduced damping and improved impact resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If uniform thickness and uniform through-hole depth are used, then manufacturing is simplified, but damping becomes excessively large

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoiddamping

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent applies local quality by varying the through-hole depth at different locations within the movable body. Specifically, through-holes in the first region (closer to the rotation axis) have a first depth while through-holes in the second region (farther from the rotation axis) have a second depth, creating non-uniform damping characteristics tailored to different functional zones of the structure.

Inventive Principle:

Principle #3Local quality

2Loss of energy

If through-holes are added to reduce damping, then damping decreases, but impact resistance deteriorates

Engineering Contradiction:

ImprovedampingVSAvoidimpact resistance

Core Design Contradiction:

Loss of energyVSStrength

Solution Approach 1:

The patent segments the movable body into multiple regions (first region and second region) with different through-hole configurations. The first region contains through-holes with a first depth while the second region contains through-holes with a second depth, allowing differentiated damping control and impact resistance in different zones of the movable body.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If constant gap distance between electrodes is used, then manufacturing is simplified, but sensitivity cannot be further increased

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidsensitivity

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies local quality by varying the gap distance between electrodes at different locations. The first gap distance in the first region is made smaller than the second gap distance in the second region, creating non-uniform electric field distribution that enhances sensitivity while maintaining manufacturability through systematic variation rather than complete redesign.

Inventive Principle:

Principle #3Local quality

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 achieves high sensitivity and impact resistance by narrowing the gap distance in the first region and utilizing through-holes and elastic portions to disperse collision energy, enabling operation across a wider frequency range.

Implementation Method 1

the movable body is provided with an elastic portion at a position overlapping the stopper in a plan view viewed from the Z axis direction

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

a first through-hole group is provided in the first region, and a second through-hole group is provided in the second region

Methodology Applied

Scientific EffectAir flow damping reduction: Damping

Data Source

PatentUS20250271462A1Physical Quantity Sensor, Physical Quantity Sensor Device, And Inertial Measurement Unit

Publication Date: 2025.08.28 SEIKO EPSON CORP

AI summary

A physical quantity sensor includes a substrate provided with a first fixed electrode, a movable body provided to be swingable with respect to the substrate about a rotation axis along a Y axis, and a stopper restricting rotation of the movable body. The movable body is provided with an elastic portion at a position overlapping the stopper in a plan view viewed from the Z axis direction. The first mass portion includes a first region, and a second region far from the rotation axis. A first gap distance of a first gap between the first mass portion and the first fixed electrode in the first region is smaller than a second gap distance of a second gap between the first mass portion and the first fixed electrode in the second region.