Variable Wavelength Optical Device With Independent Fabry-Perot Filters

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Solution Overview

Problem

Existing optical devices with multiple Fabry-Perot filters suffer from reduced transmittance and precision in wavelength dispersion due to optical multiple interferences caused by film connections between movable mirrors, leading to decreased light passage and measurement accuracy.

Innovation Solution

The optical device employs dielectric multilayer films for reflective surfaces and gap-changing units with electrostatic attraction to adjust the distance between reflective films, allowing for variable wavelength dispersion without interference, thereby increasing transmittance and precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If movable mirrors of multiple Fabry-Perot filters are brought into contact with each other using a film-shaped connection, then the wavelength variable band can be broadened, but optical multiple interferences occur between the movable mirrors causing reduced transmittance and measurement precision

Engineering Contradiction:
Improvewavelength variable bandVSAvoidtransmittance and measurement precision
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent extracts and removes the film-shaped connection between movable mirrors that causes optical multiple interferences. By eliminating this connecting film, the harmful optical interference is removed while the movable mirrors can still function independently to provide broad wavelength variable band capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a reflective film as an intermediary element between the movable mirrors. This reflective film serves as a mediator that prevents direct optical interaction between movable mirrors (eliminating multiple interferences) while still allowing the system to achieve broad wavelength variable band through coordinated operation of multiple filters.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If the gap between movable mirrors is adjusted to optimize transmittance for a specific wavelength, then transmittance for that wavelength is improved, but transmittance for other wavelengths decreases due to the third filter effect

Engineering Contradiction:
Improvetransmittance for target wavelengthVSAvoidwavelength range coverage
Core Design Contradiction:
Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The patent segments the optical system into independent Fabry-Perot filter units, each with its own movable mirror and reflective film. This segmentation allows each filter to operate independently at its optimal gap distance for specific wavelength ranges, while the collection of segmented filters collectively provides broad wavelength coverage without mutual interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs dynamic adjustment of gap distances between reflective films in each Fabry-Perot filter unit. By dynamically changing the gap distance, the system can optimize transmittance for different target wavelengths, enabling the wavelength variable band to be adjusted according to measurement requirements while maintaining high transmittance.

Inventive Principle:
Principle #15Dynamics

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 enhances transmittance for target wavelengths and reduces interference effects, enabling high-precision wavelength dispersion across a broader range with increased light passage, improving the accuracy of spectrometric measurements.

Implementation Method 1

a first reflective film and a second reflective film which is opposite in direction to the first substrate with the first reflective film in between. Edge portions of the first reflective film are brought into contact with the second reflective film, and a part of a center portion of the first reflective film is positioned to face the second reflective film with a first gap in between.

Methodology Applied
Scientific EffectOptical interference: Interference

Implementation Method 2

gap-changing units with electrostatic attraction to adjust the distance between reflective films

Methodology Applied
Scientific EffectElectrostatic attraction: Electrostatics

Data Source

PatentEP3640690B1Optical device and electronic apparatus
Publication Date: 2023.06.21 SEIKO EPSON CORP
  • EP3640690B1 patent drawingFigure 1
  • EP3640690B1 patent drawingFigure 2
  • EP3640690B1 patent drawingFigure 3

AI summary

Provided is an optical device including a first wavelength variable interference filter in which a first reflective film and a second reflective film face each other with a first gap in between; a second wavelength variable interference filter in which a third reflective film and a fourth reflective film face each other with a second gap in between; and a first substrate having a transmissive property, which has a first surface and a second surface which is opposite in direction to the first surface, in which the second reflective film is provided on the first surface of the first substrate, and in which the third reflective film is provided on the second surface of the first substrate.