Actuator Control Device for Wavelength Filter Gap Error Detection

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Solution Overview

Problem

Existing variable wavelength interference filters lack a mechanism to detect errors in feedback control, leading to potential misalignment of gap dimensions between reflective films, which can result in inaccurate wavelength filtering and measurement.

Innovation Solution

An actuator control device with a feedback loop that includes a deviation detection unit to monitor the absolute deviation between detected and set values, allowing for error detection and parameter correction to ensure accurate gap dimension control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If feedback control is implemented to control the drive voltage applied to the actuator, then the drive amount can be adjusted to approach the setting value, but there is no mechanism to detect whether the feedback control is performed correctly or if errors occur

Engineering Contradiction:

Improvedrive amount control precisionVSAvoidfeedback control error detection capability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent implements a feedback control loop that monitors the drive amount and adjusts the drive voltage accordingly. The control unit receives detection values from the detection unit and compares them with the setting value, then adjusts the drive voltage to minimize the deviation. This closed-loop feedback mechanism ensures accurate control of the actuator's drive amount while maintaining system reliability.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces a control unit as an intermediary between the detection unit and the actuator. The control unit processes the detection values, compares them with setting values, and generates appropriate drive voltages. This intermediary component enables the system to detect control errors and adjust parameters to maintain accurate operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the gap amount between reflective films is changed by applying voltage to the electrostatic actuator, then the wavelength filtering can be adjusted, but the system cannot confirm whether the gap amount reaches the target value or if feedback control errors occur

Engineering Contradiction:

Improvewavelength filtering adjustabilityVSAvoidgap amount measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent employs a feedback control system where the detection unit continuously monitors the gap amount between reflective films and feeds this information back to the control unit. The control unit compares the detected gap amount with the target value and adjusts the drive voltage to achieve precise wavelength filtering at the desired gap dimension.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces direct mechanical measurement of the gap amount with an indirect detection method. Instead of mechanically measuring the physical distance, the system uses detection units to sense the gap amount and converts this information into electrical signals for processing and control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables reliable detection of feedback control errors, stabilizing the drive amount within predetermined thresholds, ensuring accurate and stable wavelength filtering and measurement.

Implementation Method 1

electrostatic actuator facing each other are respectively disposed on each substrate. In such a variable wavelength interference filter, a voltage is applied to the electrostatic actuator by a control circuit and thereby a gap amount (interval dimension) between the reflective films is changed

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Implementation Method 2

a potential of the electrostatic capacitance monitor electrode is detected by an electrostatic capacitance detection circuit

Methodology Applied

Scientific EffectElectrostatic capacitance: Capacitance

Data Source

PatentUS9547166B2Actuator control device, optical module, and electronic apparatus

Publication Date: 2017.01.17 SEIKO EPSON CORP

AI summary

A spectroscopic measurement apparatus includes an actuator that is driven by applying a drive voltage, a gap detector that detects a dimension of a gap, and a voltage control section including a feedback loop that controls the drive voltage depending on a detection result of the gap detector. The voltage control section includes a comparator that outputs a voltage signal at a High level VH if an absolute value of a deviation between a drive amount of the actuator and a setting value of the drive amount exceeds a predetermined threshold based on the detection result after a predetermined time elapses from the start of driving of the actuator.