Night Vision Binoculars With Folded Optical Path

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Solution Overview

Problem

Conventional night vision systems pose ergonomic constraints due to their bulk and protuberant shape, causing fatigue and reduced mobility, especially in low-light conditions, and generate parallax and obstruction issues when worn on the head.

Innovation Solution

A compact night vision binocular design featuring a bent optical system with adjustable ocular paths, a video sensor-equipped light intensifier tube, and an auxiliary display device, utilizing a semi-reflecting plate or splitter cube for image splitting, and adjustable shutters for independent image viewing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a conventional night vision system with aligned lens-tube-eyepiece is used, then the optical path is simple, but the equipment becomes bulky and causes ergonomic problems

Engineering Contradiction:
Improveoptical path simplicityVSAvoidequipment bulk
Core Design Contradiction:
Device complexityVSVolume of moving object

Solution Approach 1:

The patent bends the optical path from a straight linear arrangement into a folded configuration using mirrors and beam splitters. The optical path is redirected at right angles multiple times, transforming the spatial arrangement from one-dimensional linear to three-dimensional folded, thereby reducing the overall length and bulk of the device while maintaining the complete optical path.

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

Solution Approach 2:

The patent nests multiple optical paths within a compact volume by using a beam splitter to create first and second optical paths that are folded back on themselves. The mirrors and beam splitters are arranged so that the optical paths are nested within each other, allowing both eyepieces to be positioned close together while maintaining separate complete optical paths from the objective lenses.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Length of moving object

If the objective and intensifier are oriented perpendicular to the line of sight, then the dimension along the line of sight is reduced, but parallax and obstruction problems occur

Engineering Contradiction:
Improvedimension along line of sightVSAvoidparallax and obstruction
Core Design Contradiction:
Length of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent uses a series of mirrors to fold the optical path at right angles, allowing the objective lenses to be positioned perpendicular to the line of sight while redirecting the light paths to emerge parallel to the original line of sight. This dimensional transformation eliminates parallax by aligning the optical axes with the line of sight while maintaining the compact perpendicular arrangement of the objective lenses.

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

3Ease of manufacture

If a protuberant lens-tube-eyepiece alignment is used, then the optical components are easily aligned, but the center of gravity shifts and causes neck fatigue

Engineering Contradiction:
Improvecomponent alignmentVSAvoidcenter of gravity position
Core Design Contradiction:
Ease of manufactureVSWeight of moving object

Solution Approach 1:

The patent folds the optical path using mirrors arranged at right angles, allowing the heavy objective lenses and intensifier tube to be positioned closer to the user's eye rather than extending forward. This redistributes the weight along the optical path, moving the center of gravity backward toward the user's head and reducing the forward protrusion that causes neck fatigue.

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

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

The design reduces the binocular's size and weight, minimizes parallax, and allows for adjustable fit, enhancing user mobility and comfort while enabling simultaneous or separate viewing of scene and auxiliary images.

Implementation Method 1

A large aperture lens forms an image of the observed scene on the input surface

Methodology Applied
Scientific EffectOptical imaging: Lens

Implementation Method 2

comprising a photocathode serving as the input surface, a microchannel electron transfer and multiplication system

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 3

a microchannel electron transfer and multiplication system

Methodology Applied
Scientific EffectElectron multiplication: Electron Avalanche

Implementation Method 4

and a screen phosphor serving as exit surface. A large aperture lens forms an image of the observed scene on the input surface, then the image is electronically intensified, and finally returned to the phosphor screen to be viewed

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 5

Biocular vision is achieved by splitting the flow exiting the tube over two ocular pathways using an optical splitter

Methodology Applied
Scientific EffectBeam splitting: Reflection

Data Source

PatentEP1998208B1Night vision binoculars
Publication Date: 2013.02.27 SAFRAN ELECTRONICS & DEFENSE SAS
  • EP1998208B1 patent drawingFigure 1~2
  • EP1998208B1 patent drawingFigure 3

AI summary

The binoculars have a reflection plane (8') common to optical paths (BYZC, BCW). Optical combination has two convergent groups (V1, V2, V1', V2') situated on both sides of a bent reflecting surface (5) and the plane (8'), to form intermediate images on the paths, respectively. Two bent reflecting surfaces (6, 7) send images to the plane (8') so that the images are sent towards ocular paths of respective axes (CA'', WA') parallel to sight angle (AX), where the plane (8') forms a bent on the path (BCW).