Interferometer Temperature-Dependent Reflector Beam Balance

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Solution Overview

Problem

Existing interferometer systems with multiple beam splitters require complex and precise alignment, making it difficult to adjust the reflection/transmission ratios, and existing low-coherence interferometers face challenges in optimizing the power ratio between reference and sample beams.

Innovation Solution

Incorporating a continuous variable broadband reflector with a temperature-dependent reflector in the beam splitter to adjust the radiation intensity balance between measurement and reference beams, allowing for precise and continuous adjustments without the need for multiple beam splitters, and using a scanner and processor to generate a correlogram for surface property determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple beam splitters are used to adjust reflection/transmission ratios, then different reflective values can be examined, but the device complexity increases and precise alignment is required

Engineering Contradiction:
Improveability to examine objects with different reflective valuesVSAvoidcomplexity of carrier means and alignment requirements
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses a temperature-dependent reflector where the reflection/transmission ratio is continuously adjustable by changing the temperature parameter. This eliminates the need for multiple fixed beam splitters and their complex alignment mechanisms, while still allowing examination of objects with different reflective values through continuous parameter adjustment.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical system of multiple beam splitters on a carrier means with a thermal-optical system. Instead of mechanically positioning different beam splitters, the system uses temperature control to dynamically adjust the reflector's properties, substituting mechanical complexity with thermal control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If fixed reflection/transmission ratios are used, then the device structure is simpler, but small adjustments of the reflection transmission ratio are difficult

Engineering Contradiction:
Improvesimplicity of device structureVSAvoidability to make small adjustments of reflection transmission ratio
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent transforms the static, fixed reflection/transmission ratios into a dynamic system where the ratios can be continuously adjusted. The temperature-dependent reflector allows real-time modification of beam splitting ratios, enabling fine adjustments while maintaining a relatively simple device structure without multiple movable components.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If the power ratio between reference and sample beam is not optimized, then the interferometer system is simpler, but the interference signal quality deteriorates

Engineering Contradiction:
Improvesimplicity of intensity balance adjustmentVSAvoidquality of interference signal
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the temperature of the temperature-dependent reflector is adjusted based on the detected interference signal quality. The system monitors the interference pattern and dynamically adjusts the temperature to optimize the power ratio between reference and sample beams, ensuring maximum signal quality while maintaining simple device architecture.

Inventive Principle:
Principle #23Feedback

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 solution enables precise adjustment of the interference radiation intensity, optimizing the balance between measurement and reference beams, resulting in improved interferometer performance with equal intensity at the detector, reducing complexity and radiation loss.

Implementation Method 1

the continuous variable broadband reflector comprises a temperature dependent reflector which reflectivity is dependent on the temperature

Methodology Applied
Scientific EffectTemperature dependent reflectivity: Thermochromism

Implementation Method 2

a beam splitter to split the broadband illumination beam in a reference beam for reflection on a reference reflector and a measurement beam for reflection on the surface of the sample

Methodology Applied
Scientific EffectBeam splitting: Reflection

Implementation Method 3

a detector to receive an interference radiation intensity created between the reference beam reflected from the reference reflector and the reflected measurement beam from the surface of the sample to generate an interference signal

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP2813801B1Interferometer system and method to generate an interference signal of a surface of a sample
Publication Date: 2018.10.31 MITUTOYO CORP
  • EP2813801B1 patent drawingFigure 1a
  • EP2813801B1 patent drawingFigure 1b~2
  • EP2813801B1 patent drawingFigure 3~4

AI summary

The invention relates to an interferometer system to generate an interference signal of a surface of a sample with: a broadband illuminator to provide a broadband illumination beam; a beam splitter to split the broadband illumination beam in a reference beam for reflection on a reference reflector and a measurement beam for reflection on the surface of the sample; and, a detector to receive an interference radiation intensity created between the reference beam reflected from the reference reflector and the reflected measurement beam from the surface of the sample to generate an interference signal. The interferometer system having a continuous variable broadband reflector in the beam splitter and/or the reference reflector to adjust the broadband radiation intensity balance between the measurement beam and the reference beam.