Variable Wavelength Filter Control for Faster Gap Stabilization

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Solution Overview

Problem

The existing variable wavelength etalon technology faces challenges in quickly changing the wavelength of transmitted light due to overshooting and prolonged stabilization time, as the first electrostatic actuator does not immediately displace the movable portion when the target wavelength is changed, leading to excessive displacement and prolonged convergence of the inter-reflective film gap.

Innovation Solution

A control method for a variable wavelength filter that includes a first actuator driven by a target distance and a second actuator with feedback control, where the relative position is changed by driving the first actuator according to the new target distance, and feedback control on the second actuator is initiated only after a predetermined inhibition time has elapsed, ensuring stable positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If feedback control is immediately applied to the second actuator when target wavelength changes, then the control precision is improved, but the stabilization time increases due to overshooting

Engineering Contradiction:

Improvecontrol precisionVSAvoidstabilization time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The control method applies preliminary action by having the first actuator perform coarse positioning before the second actuator performs fine positioning with feedback control. This sequence prevents the feedback control from immediately reacting to large deviations that would cause overshooting, thereby reducing stabilization time while maintaining precision.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The positioning system is segmented into two distinct actuators with different functions: the first actuator handles coarse positioning to bring the system close to the target wavelength, while the second actuator handles fine positioning with feedback control. This segmentation allows each actuator to operate in its optimal range, preventing overshooting and reducing overall stabilization time.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If the first actuator is driven to change wavelength, then the wavelength tuning range is improved, but the positioning accuracy deteriorates due to overshooting

Engineering Contradiction:

Improvewavelength tuning rangeVSAvoidpositioning accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The positioning function is segmented between two actuators: the first actuator provides broad wavelength tuning capability with lower precision, while the second actuator provides fine positioning with high precision through feedback control. This segmentation enables both wide tuning range and high positioning accuracy to be achieved simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first actuator serves as an intermediary that performs preliminary positioning to bring the system close to the target wavelength before the second actuator performs precise positioning. This intermediary action prevents the feedback-controlled second actuator from having to correct large deviations, thereby maintaining positioning accuracy while enabling broad wavelength tuning.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 reduces the time required for the filter to stabilize at the new target wavelength, minimizing overshooting and fluctuation, thereby enhancing the efficiency of wavelength change processes.

Implementation Method 1

a first electrostatic actuator, a second electrostatic actuator

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Implementation Method 2

a first electrostatic actuator, a second electrostatic actuator, and a movable portion provided with the reflective film and displaced by the first electrostatic actuator and the second electrostatic actuator

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Data Source

PatentUS12140749B2Variable wavelength filter, variable wavelength filter control method, and non-transitory computer-readable storage medium storing computer program

Publication Date: 2024.11.12 SEIKO EPSON CORP

AI summary

Variable wavelength filter including two reflective films facing each other and an actuator group for changing a relative position between the two reflective films is controlled. The actuator group includes a first actuator that is driven according to a target distance between the two reflective films and a second actuator in which a feedback control is performed according to the target distance and a detection value of a distance between the two reflective films. Control method includes (a) receiving a new target distance between the two reflective films, (b) driving the first actuator according to the new target distance, and (c) performing the feedback control on the second actuator according to the new target distance and the detection value of the distance between the two reflective films. When a predetermined condition is satisfied, after start of the (b), and after elapse of a predetermined inhibition time, the (c) is started.