Dual-Field Catadioptric Telescope With Single-Sensor Image Superposition

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Solution Overview

Problem

Existing multi-field imaging systems are bulky, costly, and lack compactness, often requiring multiple sensors and optical assemblies, which can be fragile and mechanically inefficient, leading to reduced sensitivity and inability to acquire simultaneous images.

Innovation Solution

A dual-field telescope design with aligned wide-field and narrow-field optical paths using mirrors, a single sensor, and adjustable diaphragms to superimpose images, ensuring robustness and compact integration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple sensors and optical assemblies are used to achieve multi-field imaging, then the imaging capability is improved, but the system becomes bulky and complex

Engineering Contradiction:
Improvemulti-field imaging capabilityVSAvoidsystem structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple optical paths (wide-field and narrow-field) into a single integrated telescope system with one sensor. The optical paths are merged through a common optical train, eliminating the need for separate sensors and optical assemblies for each field of view, thus reducing system complexity while maintaining multi-field imaging capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single sensor serves multiple functions by receiving images from both wide-field and narrow-field optical paths. The telescope system is designed to be multi-functional, capable of detecting objects in wide fields and identifying them in narrow fields simultaneously, replacing what would traditionally require multiple specialized sensors.

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

2Adaptability or versatility

If a beam splitter is used to mix two imaging paths, then the imaging capability is improved, but sensor sensitivity is reduced

Engineering Contradiction:
Improvedual-field imaging capabilityVSAvoidsensor sensitivity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the optical paths using an aperture mask that spatially separates wide-field and narrow-field rays before they reach the sensor. This segmentation allows each field type to be directed to appropriate sensor regions without requiring a beam splitter, thereby maintaining full sensor sensitivity for both imaging paths simultaneously.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If lenses are placed at the end of the optical system, then the imaging capability is improved, but the system becomes fragile and vulnerable to damage

Engineering Contradiction:
Improveimaging performanceVSAvoidrobustness against shocks
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent inverts the traditional lens placement by using mirrors throughout the optical path and positioning the aperture mask at the entrance of the optical system rather than at the exit. This inversion places the vulnerable aperture mask (which could be made robust) at the front, protecting the sensor and internal components from direct exposure to shocks and projectiles, thereby improving system robustness while maintaining imaging performance.

Inventive Principle:
Principle #13The other way round (Inversion)

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 simultaneous acquisition of wide-field and narrow-field images on a single sensor, maintaining sensitivity and robustness against shocks, while being compact enough for integration into various housings.

Implementation Method 1

the wide-field optical path comprising a first convex mirror and a second concave mirror perforated in its center

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

the narrow-field optical path comprising a third concave mirror and a fourth mirror positioned at the level of a non-reflective surface of the first convex mirror

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4320473B1Dual-field catadioptric telescope
Publication Date: 2025.12.10 SAFRAN ELECTRONICS & DEFENSE (FR)
  • EP4320473B1 patent drawingFigure 1
  • EP4320473B1 patent drawingFigure 2
  • EP4320473B1 patent drawingFigure 3

AI summary

This dual-field telescope (2) comprises, aligned on the same optical axis (1), a large-field optical channel (5), a small-field optical channel (6) and a sensor (9) of electromagnetic radiation, the large-field optical channel (5) comprising a convex first mirror (7) and a concave second mirror (8) that is perforated at its centre, the small-field optical channel (6) comprising a concave third mirror (10) and a fourth mirror (11) that is positioned level with a non-reflective surface (7a) of the convex first mirror (7) and has a diameter smaller than or equal to the diameter of the convex first mirror.