Piezoelectric Valve State Detection for Compact Fluid Control

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Solution Overview

Problem

In semiconductor manufacturing, existing fluid control devices with limit switches hinder miniaturization due to their size and placement requirements, necessitating a more compact and integrated solution for detecting valve open/close states.

Innovation Solution

A valve device utilizing a piezoelectric element as both an actuator and detector, generating voltage based on its position to determine the open/close state, eliminating the need for limit switches and enabling higher responsiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If limit switches are used to detect valve open/close status, then detection reliability is improved, but device size increases and miniaturization is prevented

Engineering Contradiction:

Improvedetection reliabilityVSAvoiddevice size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent combines the actuator and detector into a single integrated unit. The piezoelectric element serves dual functions: it acts as an actuator to drive the valve element and as a detector to sense the open/close status by measuring its own deformation. This merging eliminates the need for separate limit switches, thereby reducing device size while maintaining detection reliability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The piezoelectric element is designed to perform multiple functions simultaneously. It functions as both an actuator (converting electrical energy to mechanical motion to open/close the valve) and a detector (sensing its own position through piezoelectric effect). This multi-functionality reduces the number of components needed, enabling miniaturization while preserving reliable detection capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If limit switches are used for valve status detection, then detection accuracy is improved, but integration is reduced and responsiveness deteriorates

Engineering Contradiction:

Improvedetection accuracyVSAvoidresponsiveness

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

By merging the actuator and detector into one piezoelectric element, the system achieves direct coupling between actuation and sensing. This eliminates mechanical linkages and signal transmission delays associated with separate limit switches, thereby improving responsiveness while maintaining detection accuracy through direct measurement of valve position.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the mechanical limit switch system with an electroceramic-based piezoelectric system. The piezoelectric element directly converts mechanical deformation into electrical signals for detection, eliminating the need for mechanical contacts and complex linkage mechanisms. This substitution improves both responsiveness (faster signal generation) and integration (fewer mechanical parts).

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Speed

If compact integrated fluid control devices are used, then responsiveness is improved, but detection capability is lost without limit switches

Engineering Contradiction:

ImproveresponsivenessVSAvoiddetection capability

Core Design Contradiction:

SpeedVSDifficulty of detecting and measuring

Solution Approach 1:

The piezoelectric element serves itself by using its own deformation during actuation as the basis for detection. As the piezoelectric element expands or contracts to move the valve, it simultaneously generates an electrical signal that indicates its position. This self-service capability provides detection functionality without requiring external limit switches, maintaining detection capability while achieving compact integration and high responsiveness.

Inventive Principle:

Principle #25Self-service

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 allows for precise and responsive control of fluid flow rates without the need for limit switches, enhancing the compactness and integration of semiconductor manufacturing apparatuses.

Implementation Method 1

a detecting unit for detecting open/close state of the flow path based on the voltage generated by the piezoelectric element

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

an adjusting mechanism utilizing a piezoelectric element for adjusting the opening degree of the flow path determined by the valve element

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS11187346B2Valve device, its control device, control methods using the same, fluid control device and semiconductor manufacturing apparatus

Publication Date: 2021.11.30 FUJIKIN INC

AI summary

A control device for a valve device can detect open/close state of the valve device without using limit switches. The valve device includes a diaphragm for opening and closing a flow path for flowing a fluid, a coil spring for biasing the diaphragm in the closing direction of flow path, a main actuator for driving it against the biasing force of the coil spring, and an adjusting actuator using a piezoelectric element for adjusting the opening degree of the flow path determined by the diaphragm. The controller detects the open/close state of flow path based on the voltage generated by the piezoelectric element of the adjusting actuator, and controls valve device using the detection signal.