Adjustable-Magnification Viewfinder With Polarization Image Fusion

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Solution Overview

Problem

Existing riflescopes and shooting glasses face challenges in combining multiple functionalities such as magnification, image fusion, and real-time data display without increasing size, weight, or reducing luminance, and are prone to vitreous reflections and alignment issues.

Innovation Solution

A clear viewfinder system utilizing polarization states of light to switch between magnified and non-magnified views, incorporating afocal and display modules with polarization splitters, delay plates, and a controllable liquid crystal cell for adjustable magnification and image superposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If intensity separation is used to combine multiple imaging paths, then multiple functionalities can be achieved, but luminance is reduced on each imaging path

Engineering Contradiction:
Improvemultiple imaging pathsVSAvoidluminance
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The system segments the imaging paths using polarization separation, where different polarization states (s-polarized and p-polarized light) are directed to different optical paths. This allows multiple imaging functionalities to operate simultaneously without reducing luminance on each path, as each polarization component maintains its full intensity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses polarization state changes (analogous to color changes in the broader sense of optical property changes) to separate and combine multiple imaging paths. By utilizing orthogonal polarization states, the system can route different imaging paths through the same optical components without intensity loss.

Inventive Principle:
Principle #32Color changes

2Adaptability or versatility

If pupil separation is used to combine multiple imaging paths, then multiple functionalities can be achieved, but pupil size and field of view are reduced on each imaging path

Engineering Contradiction:
Improvemultiple imaging pathsVSAvoidpupil size
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The system segments the pupil and field of view using polarization separation. Different polarization states are directed to different imaging paths, allowing each path to maintain full pupil size and field of view. The polarization splitter divides the incoming light based on polarization state rather than spatial position, preserving the full aperture for each path.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If mechanical switching is used to combine multiple imaging paths, then multiple functionalities can be achieved, but simultaneous image viewing on both paths is not possible

Engineering Contradiction:
Improvemultiple imaging pathsVSAvoidsimultaneous viewing
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system uses polarization-based segmentation to enable simultaneous viewing on multiple imaging paths. Unlike mechanical switching that sequentially directs light, the polarization splitter simultaneously directs different polarization components to different paths, allowing the user to view multiple images at the same time through different exit pupils or displays.

Inventive Principle:
Principle #1Segmentation

4Adaptability or versatility

If electronic fusion is used to combine multiple imaging paths, then multiple functionalities can be achieved, but size, mass, and cost increase

Engineering Contradiction:
Improvemultiple imaging pathsVSAvoidsystem mass
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The invention merges multiple imaging paths into a single optical train using polarization-based beam combining. Multiple images are superimposed on the same optical path and exit through a common exit pupil, eliminating the need for separate optical systems for each function. This significantly reduces the overall size, mass, and cost compared to electronic fusion approaches that would require separate sensors and processing systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses a universal optical path that can simultaneously handle multiple imaging functions through polarization multiplexing. A single objective lens and optical train serve multiple purposes by utilizing different polarization states, eliminating the need for multiple dedicated optical systems and reducing overall system mass.

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

5Ease of operation

If clear sights are used for both eyes open aiming, then environmental monitoring is improved, but magnification capability is lost

Engineering Contradiction:
Improveboth eyes open aimingVSAvoidmagnification
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system segments the visual field using polarization separation, directing magnified and non-magnified images to different polarization paths. This allows the user to maintain both eyes open for environmental awareness while simultaneously accessing magnified views through the appropriate polarization channel or display.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention merges clear sight and magnified sight functionalities into a single optical system. By using polarization-based beam combining, the system superimposes magnified and non-magnified images or directs them to different displays, allowing the user to switch between or combine both modes without changing physical configurations.

Inventive Principle:
Principle #5Merging (Combining)

6Measurement precision

If monoculars with bi-afocal magnification system are used, then magnification capability is improved, but eye positioning precision is required

Engineering Contradiction:
ImprovemagnificationVSAvoideye positioning
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system merges multiple magnification paths into a single exit pupil using polarization-based beam combining. This allows the user to access different magnification levels without needing to precisely position the eye in separate exit pupils, as all magnified images are combined and presented through a common viewing area.

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

Enables a compact, modular, and lightweight system that allows easy variation of magnification, reduces vitreous reflections, and facilitates simultaneous image viewing and data processing, enhancing user comfort and accuracy.

Implementation Method 1

a removable and switchable rectilinear polarizer, so as to transmit at least a first rectilinear polarization state of light coming from said scene, called state A, or a second rectilinear polarization state of the light, called B

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 2

a first polarization splitter element arranged to reflect a polarization state A of light transmitted by said rectilinear polarizer

Methodology Applied
Scientific EffectPolarization-dependent reflection: Polarisation

Implementation Method 3

a half-wave plate called a distribution plate, arranged on the path of the AG light and the direct light, after the first polarization splitter element

Methodology Applied
Scientific EffectHalf-wave plate polarization transformation: Polarisation

Implementation Method 4

an electronically controllable liquid crystal cell adapted to introduce a phase delay varying from 0° to 180° modulo 360°

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Implementation Method 5

an optical objective adapted to collimate said display light

Methodology Applied
Scientific EffectCollimation: Lens

Implementation Method 6

a first and a second catadioptric sub-assemblies located on either side of the first polarization splitter element

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 7

a first and a second catadioptric sub-assemblies located on either side of the first polarization splitter element

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 8

a first and a second so-called afocal delay plates arranged on the path of the reflected light, on either side of the first polarization splitter element

Methodology Applied
Scientific EffectOptical path delay:

Implementation Method 9

a mirror adapted to transform a polarization state A of the AG light and the direct light reflected by the second polarization splitter element into a polarization state B

Methodology Applied
Scientific EffectPolarization transformation upon reflection: Polarisation

Data Source

PatentEP4314695B1Adjustable-magnification viewing system
Publication Date: 2025.08.06 THALES SA
  • EP4314695B1 patent drawingFigure 1
  • EP4314695B1 patent drawingFigure 2A
  • EP4314695B1 patent drawingFigure 2B

AI summary

Scope (LT) viewing a scene, said scope comprising a first optical subassembly (1), called the afocal module, and a second optical subassembly (2), called the display module, said afocal module (1) comprising: a removable and switchable linear polarizer (POL1), a first polarization splitter element (LS1), an afocal optical system for the first polarization splitter element (LS1), said display module comprising: a "distributing" half-wave plate (HP), a display (EA), an optical objective (Obj) designed to collimate the display light; a second polarization splitter element (LS2) arranged after the distributing half-wave plate (HP).