Uniform Velocity Driving for Wavelength Variable Interference Filters

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Solution Overview

Problem

Spectroscopic measurement apparatuses with wavelength variable interference filters face challenges in achieving constant measurement wavelength intervals due to non-uniform distance change velocities between reflection films, leading to inefficient data acquisition and prolonged measurement times.

Innovation Solution

A spectroscopic measurement apparatus with a driving circuit that controls an electrostatic actuator to change the distance between reflection films at a uniform velocity, using a pulse voltage and low pass filter to generate a driving voltage with a first-order-lag waveform, ensuring consistent wavelength interval measurements by acquiring signals in a constant cycle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If an analog voltage is applied to the electrostatic actuator for cyclic driving, then the wavelength variable interference filter can be driven continuously, but the distance change velocity varies in a sinusoidal wave pattern causing non-uniform measurement wavelength intervals

Engineering Contradiction:

Improvedistance change velocityVSAvoidmeasurement wavelength interval uniformity

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by transitioning from a static analog voltage application to a dynamic pulse voltage driving method. The driving control section generates pulse voltages with varying widths based on a predetermined waveform, enabling the electrostatic actuator to change the reflection film distance at substantially uniform velocity, thereby resolving the sinusoidal velocity variation issue.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the voltage parameter from continuous analog voltage to pulsed voltage with variable width. The pulse voltage width is modulated according to a predetermined waveform to control the electrostatic actuator's movement velocity, achieving substantially uniform distance change velocity and constant measurement wavelength intervals.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If scan processing is performed at a position of high distance change velocity, then measurement speed is improved, but non-uniformity in measurement wavelength interval appears and multiple scans are required

Engineering Contradiction:

Improvemeasurement speedVSAvoidmeasurement wavelength interval uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent ensures continuous useful action by maintaining substantially uniform distance change velocity throughout the entire scan range. The pulse voltage driving method keeps the electrostatic actuator operating at optimal velocity without sinusoidal variations, allowing single-scan completion with both high speed and uniform wavelength intervals.

Inventive Principle:

Principle #20Continuity of useful action

3Manufacturing precision

If multiple scans are performed to obtain uniform measurement wavelength intervals, then measurement precision is improved, but measurement time is prolonged

Engineering Contradiction:

Improvemeasurement wavelength interval uniformityVSAvoidmeasurement time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent implements preliminary action by pre-calculating and storing the predetermined waveform data that corresponds to the desired uniform velocity profile. The driving control section retrieves and applies this predetermined waveform to generate the appropriate pulse voltage sequence, enabling single-scan uniform measurement without requiring multiple corrective scans.

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 allows for rapid and precise spectroscopic measurements with constant wavelength intervals, reducing the need for multiple scans and minimizing measurement time while maintaining high resolution.

Implementation Method 1

a wavelength variable interference filter including a first reflection film, a second reflection film, and an electrostatic actuator that changes a distance between the first reflection film and the second reflection film

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Implementation Method 2

using a pulse voltage and low pass filter to generate a driving voltage with a first-order-lag waveform

Methodology Applied

Scientific EffectFirst-order-lag waveform filtering: Filter (electronic)

Data Source

PatentUS10175108B2Spectroscopic measurement apparatus, driving circuit, and spectroscopic measurement method

Publication Date: 2019.01.08 SEIKO EPSON CORP

AI summary

A spectroscopic measurement apparatus includes a wavelength variable interference filter and a driving circuit. The wavelength variable interference filter includes a fixed reflection film, a movable reflection film that faces the fixed reflection film, and an electrostatic actuator that changes a distance between the fixed reflection film and the movable reflection film. The driving circuit drives the electrostatic actuator in such a way that the distance between the fixed reflection film and the movable reflection film changes at a uniform velocity.