Monolithic Spectrometer Compact Optical Path Design

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Solution Overview

Problem

There is a need for an improved monolithic spectrometer that is both compact and easy to manufacture, while maintaining or enhancing spectral resolving power.

Innovation Solution

The design incorporates a single optical surface combining collimating and focusing functions, with the optical path after the grating surface crossing with the path between the entry and collimating surface, allowing for increased optical path length without additional surfaces, and includes features like a curved entry surface and reflective surfaces to enhance compactness and spectral resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple separate optical surfaces are used for collimating and focusing functions, then optical performance can be optimized, but manufacturing complexity and device complexity increase

Engineering Contradiction:
Improveoptical performanceVSAvoidnumber of optical surfaces
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines the collimating surface and focusing surface into a single continuous optical surface within the monolithic body. This merging reduces the number of separate optical components from multiple discrete surfaces to one integrated surface, simplifying manufacturing while maintaining the necessary optical functions for collimating and focusing light in the spectrometer.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single optical surface performs multiple functions: it acts as both the collimating surface and the focusing surface. This multi-functional design allows one surface to replace what would traditionally require two or more separate optical elements, reducing device complexity while preserving optical performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If optical path length is increased to improve spectral resolving power, then spectral resolution improves, but device volume and complexity increase

Engineering Contradiction:
Improvespectral resolving powerVSAvoiddevice volume
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent utilizes the third dimension (depth within the monolithic body) to fold the optical path. By having the optical path cross itself within the body and using the depth dimension efficiently, the design achieves a longer optical path length between the grating and exit surface without proportionally increasing the external device volume, thus improving spectral resolution while maintaining compactness.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The optical path is nested within the monolithic body structure, with the light path folding back through the body. The optical path between the grating and exit surface is nested within the same physical envelope as the entry and collimating paths, allowing extended optical path length without increasing external dimensions.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Volume of moving object

If compact design is maintained with limited optical path length, then device size is reduced, but spectral resolving power decreases

Engineering Contradiction:
Improvedevice sizeVSAvoidspectral resolving power
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent exploits the depth dimension within the monolithic body to create a folded optical path. By routing light through multiple passes and having paths cross within the body volume, the design achieves extended optical path length necessary for high spectral resolution while keeping the external device footprint compact.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Measurement precision

If additional optical surfaces are added to increase optical path length, then spectral resolution improves, but manufacturing complexity and device complexity increase

Engineering Contradiction:
Improvespectral resolutionVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges multiple optical functions (collimating, focusing, and extended path length) into a single monolithic body with one continuous optical surface. This eliminates the need to manufacture and assemble multiple separate optical surfaces, greatly simplifying manufacturing while achieving the desired spectral resolution through the folded optical path within the single body.

Inventive Principle:
Principle #5Merging (Combining)

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 manufacturing complexity, maintains compactness, and improves spectral resolving power by increasing the optical path length between the grating and exit, while preventing unwanted light disturbances and allowing for wider light beams without clipping.

Implementation Method 1

The collimating surface is arranged to receive the entering light directed along the first part of the optical path and to reflect said entering light as a collimated beam directed along a second part of the optical path

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The grating surface is arranged to receive the collimated beam directed along the second part of the optical path and to reflect a refracted beam directed along a third part of the optical path according to a wavelength dependent refraction angle

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

The focusing surface is arranged to receive the refracted beam directed along the third part of the optical path and to focus said refracted beam directed along a fourth part of the optical path for imaging a wavelength component of the light onto a position along a spectral axis

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentEP3052907B1Monolithic spectrometer
Publication Date: 2021.04.21 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO
  • EP3052907B1 patent drawingFigure 1A~1B
  • EP3052907B1 patent drawingFigure 2A~2B
  • EP3052907B1 patent drawingFigure 3A~3B

AI summary

The present disclosure concerns a monolithic spectrometer (1) for spectrally resolving light (R). The spectrometer (1) comprises a body (2) of solid material having optical surfaces (3, 4, 5, 6, 8) arranged to guide the light (R) along an optical path (E1, E2, E3, E4) inside the body (2). A collimating surface (4) and focusing surface (6) are part of a single surface having a continuous optically functional shape. The surfaces (3,4,5,6,8) of the body (2) are arranged to have a third or fourth part (E3, E4) of the optical path between a grating surface (5) and an exit surface (8) cross (C) with a first part (E1) of the optical path between an entry surface (3) and a collimating surface (4).