Thermally Actuated Bimorph Diaphragm for Microvalve Fluid Circulation

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Solution Overview

Problem

Existing fluid circulation members in microvalves require complex and expensive manufacturing processes to achieve sufficient flexibility, often resulting in rigid diaphragms that necessitate the formation of flexible tabs or hinges, which complicates the production and increases costs.

Innovation Solution

A thermally actuated semiconductor substrate fluid circulation member with a bi-morph diaphragm, where a thin barrier layer on the support frame allows for a very thin diaphragm formation, eliminating the need for hinges or tabs by enabling selective etching and improving sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a thick diaphragm is used to provide rigidity, then structural strength is improved, but flexibility deteriorates and manufacturing complexity increases due to the need for flexible tabs or hinges

Engineering Contradiction:
Improvediaphragm rigidityVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent employs a thin diaphragm film (few micrometers thick) made of semiconductor material that provides sufficient flexibility without requiring additional flexible tabs or hinges. The thin film nature of the diaphragm allows it to bend and deform elastically under actuation while maintaining structural integrity, thereby eliminating the need for complex flexible tab structures.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the thickness parameter of the diaphragm from conventional thick structures to a thin film configuration (few micrometers). This parameter change fundamentally alters the mechanical properties, providing both the necessary flexibility and sufficient strength without requiring additional structural elements like hinges or flexible tabs.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If a thick diaphragm is used to maintain structural integrity, then manufacturing simplicity is improved, but flexibility deteriorates requiring complex hinges or tabs

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidstructural complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The thin diaphragm film serves as both the structural element and the flexible component in a single integrated structure. This eliminates the need for separate hinge or flexible tab components, simplifying the manufacturing process while maintaining structural integrity through the thin film's inherent mechanical properties.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent merges the functions of the diaphragm and the flexible hinge elements into a single thin film structure. The thin diaphragm itself provides the necessary flexibility without requiring separate hinge components, thereby combining multiple functions into one element and simplifying manufacturing.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If a thin diaphragm is used to achieve flexibility, then flexibility is improved, but manufacturing complexity increases due to selective etching requirements

Engineering Contradiction:
Improvediaphragm flexibilityVSAvoidetching process complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent introduces a sacrificial layer as an intermediary element that facilitates the formation of the thin diaphragm. This sacrificial layer is deposited on the substrate, allows for precise thickness control of the thin diaphragm, and is subsequently removed to release the thin diaphragm structure. This intermediary approach simplifies the overall manufacturing process by providing a controlled method for creating and releasing the thin film structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If conventional manufacturing methods are used with thick diaphragms, then manufacturing robustness is improved, but sensitivity deteriorates

Engineering Contradiction:
Improvemanufacturing robustnessVSAvoidfluid circulation sensitivity
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the diaphragm thickness parameter to a thin film configuration, which directly improves sensitivity to fluid pressure and flow changes. The thin diaphragm deforms more readily in response to fluid forces, enhancing the device's ability to detect and respond to fluid circulation conditions while maintaining manufacturing robustness through standardized thin film deposition processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The thin film diaphragm provides enhanced sensitivity to fluid forces due to its reduced thickness and increased flexibility. This allows the device to detect smaller pressure and flow changes, improving measurement precision and control sensitivity while maintaining reliable operation through the robustness of thin film fabrication techniques.

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

The solution results in a compact, highly sensitive fluid circulation member with a thin diaphragm, reducing manufacturing complexity and cost while enhancing flexibility and performance.

Implementation Method 1

the bimorph diaphragm comprises two superposed parts formed respectively of a layer of silicon and of a metal layer, here of nickel, these two parts being separated by a layer of silicon oxide... When the diaphragm is deformed by heating

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

a first thin layer of a barrier material for selective etching of the semiconductor substrate is placed on the support frame... the selective attack necessary to form the diaphragm

Methodology Applied
Scientific EffectSelective etching:

Data Source

PatentEP2438339B1Fluid circulation member and fluid circulation device using such a member
Publication Date: 2013.03.06 EVEON
  • EP2438339B1 patent drawingFigure 1~3
  • EP2438339B1 patent drawingFigure 4
  • EP2438339B1 patent drawingFigure 5~6

AI summary

The invention relates to a semiconductor heat-actuated circulation member (1B) including a supporting frame (10) and a bimorphous diaphragm (6) including two vertically adjacent portions (7, 8) coupled to the frame (10). A first thin film (20) of a stopping material for the selective etching of the semiconductor substrate is placed on the frame (10), while the diaphragm (6) with the two portions (7, 8) is placed on a single surface of said first thin film (20).