Reflective Polarization-Separating Diffraction Element for Compact Measurement

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Solution Overview

Problem

Reflective polarized-light separating diffraction-gratings have not been developed, making it difficult to miniaturize optical measurement devices due to the lack of understanding of how to impart a reflective property to such gratings.

Innovation Solution

A reflective polarized-light separating diffraction-element is designed with a substrate and a lattice structured body assembly on its surface, featuring lattice structures with varying azimuths aligned in a periodic manner, imparting phase and refractive index changes to separate circularly-polarized light into different diffracted orders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If transmissive polarized-light separating diffraction-gratings are used, then polarization state measurement can be achieved, but the device size becomes large due to the need for light transmission path and rotation mechanisms

Engineering Contradiction:

Improvepolarization state measurement capabilityVSAvoiddevice size

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent inverts the conventional transmissive diffraction grating design by creating a reflective polarized-light separating diffraction element. Instead of transmitting light through a grating structure, the invention uses a reflective grating where light reflects off the surface, achieving polarized light separation in a compact configuration without requiring long transmission paths or rotation mechanisms.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention extracts the essential function of polarized light separation from the complex transmissive grating system and implements it through a simplified reflective structure with specific lattice patterns, eliminating the need for bulky rotation mechanisms and long optical paths while maintaining measurement precision.

Inventive Principle:

Principle #2Taking out (Extraction)

2Volume of moving object

If reflective polarized-light separating diffraction-gratings are developed, then device miniaturization can be achieved, but the mechanism for imparting reflective property to the grating structure is not understood

Engineering Contradiction:

Improvedevice sizeVSAvoidunderstanding of reflective mechanism

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by modifying the lattice structure parameters (pitch, depth, shape) of the reflective diffraction element to achieve the desired reflective properties and polarized light separation. By optimizing these structural parameters, the invention creates a compact device with well-defined physical mechanisms.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If conventional crossed-Nicol method is used for birefringence measurement, then measurement can be performed, but rotation mechanisms are required which increase device complexity and measurement time

Engineering Contradiction:

Improvebirefringence measurement capabilityVSAvoidrotation mechanism

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical rotation system of the crossed-Nicol method with a stationary reflective polarized-light separating diffraction element. The polarized light separation is achieved through the optical properties of the lattice structure rather than mechanical rotation, simplifying the device and reducing measurement time while maintaining birefringence measurement precision.

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

This configuration allows for compact optical measurement devices by separating right- and left-handed circularly-polarized light components, enabling simultaneous detection and significantly reducing measurement time in devices like circular dichroism and birefringence measurement devices.

Implementation Method 1

a lattice structured body assembly that is provided on the reflection surface and exhibits a form birefringence (Δn*)

Methodology Applied

Scientific EffectForm birefringence: Birefringence

Implementation Method 2

the transmissive polarized-light separating diffraction-grating has a property of dividing the right-handed circularly-polarized light and the left-handed circularly-polarized light into directions of ±1 order diffracted lights

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 3

a reflection surface formed on a surface of the substrate

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS12449575B2Reflective polarized light separation and diffraction element and optical measurement device comprising same

Publication Date: 2025.10.21 JASCO CORP

AI summary

A reflective polarized-light separating diffraction-element including a substrate, a reflection surface formed on a surface of the substrate, and a lattice structured body assembly that is provided on the reflection surface and exhibits a form birefringence (Δn*). The lattice structured body assembly includes lattice structured bodies of a plurality of patterns having lattice structures of different azimuths, and these lattice structured bodies of a plurality of patterns are aligned in a predetermined direction on the reflection surface so that the azimuths of the lattice structures change in a structurally periodic manner.