3D Acceleration Pickup Structuring by Sequential Mask Etching

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Solution Overview

Problem

The manufacturing process for acceleration pickup members is complicated due to the need to mold sections with varying thicknesses and through grooves, making it difficult to apply resist using conventional methods like spin coating, spray, or dipping, especially when both deep penetrating and shallow stepped portions are involved.

Innovation Solution

A method involving a series of mask forming and etching steps using a positive resist, where the mask is progressively exposed and removed in order of thickness, from thinnest to thickest, to simplify the manufacturing of three-dimensional structural members with varying thicknesses, including a pendulum, hinge, and support sections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional resist application methods (spin coating, spray, or dipping) are used on three-dimensional structures with deep stepped portions, then the manufacturing process becomes complicated, but the resist application becomes difficult or impossible

Engineering Contradiction:
Improveresist application processVSAvoidthree-dimensional structure complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent applies resist to the flat base plate before any etching or three-dimensional structure formation. This preliminary resist application avoids the problem of applying resist to deep stepped portions, as the base plate surface is flat and accessible. The resist pattern is then transferred through subsequent etching steps to create the final three-dimensional structure with varying thicknesses.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If multiple etching steps are performed to create portions with different thicknesses, then the desired three-dimensional shape is achieved, but the manufacturing process becomes complicated

Engineering Contradiction:
Improvethickness variation precisionVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the etching process into multiple sequential steps, each targeting specific regions of the base plate. First, a first etching step creates through grooves in predetermined first regions. Then, a second etching step creates portions with first thickness in predetermined second regions. This segmented approach allows precise control over the three-dimensional shape by treating different regions independently with appropriate masking.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies masking material selectively to different regions of the base plate to achieve local quality variations. By controlling which regions are masked and which are exposed to etching, the patent creates portions with different thicknesses (through grooves, first thickness, second thickness) in specific locations. This local control enables precise three-dimensional structuring.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If deep etching is performed to create through grooves, then the desired structural features are achieved, but resist application becomes particularly difficult

Engineering Contradiction:
Improvethrough groove precisionVSAvoidresist application ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent performs resist application on the flat base plate before any deep etching is performed. This preliminary action ensures that the resist can be applied uniformly to the entire surface without the complications of deep stepped portions. The resist pattern is then maintained through the deep etching process to define the through groove locations.

Inventive Principle:
Principle #10Preliminary action

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 approach simplifies the manufacturing process by allowing for the application of resist on a flat base, reducing burrs and disconnections, and enables the production of acceleration pickup members with precise angles and thickness variations.

Implementation Method 1

a part of the mask is exposed to light and thereby removed in the mask removing step

Methodology Applied
Scientific EffectPhotochemical reaction: Photopolymerisation

Implementation Method 2

an etching step of etching an exposed portion of the base

Methodology Applied
Scientific EffectEtching:

Data Source

PatentEP3809142B1Method for manufacturing three-dimensionally structured member, acceleration pickup, and acceleration sensor
Publication Date: 2025.11.19 TOKYO KEIKI
  • EP3809142B1 patent drawingFigure 1
  • EP3809142B1 patent drawingFigure 2
  • EP3809142B1 patent drawingFigure 3

AI summary

The purpose of the present invention is to provide a method for manufacturing a three-dimensionally structured member which can be made by a simpler process. The method for manufacturing a three-dimensionally structured member includes shaping a flat plate-shaped base member 10A to produce a three-dimensionally structured member having a plurality of sections 11 to 14 that are different from one another in thickness. The manufacturing method comprises: a mask formation step for forming a mask 30 over the whole of at least one main surface of the base member 10A; a mask removal step for removing a part of the mask 30; and an etching step for etching an exposed part of the base member 10A, wherein a combination of the mask removal step and the etching step is performed on the mask 30 and the base member 10A that correspond to each of the plurality of sections 11 to 14 of the three-dimensionally structured member, in the order from thinnest to the thickest of thicknesses of the three-dimensionally structured members.