Wavefront-Coded Optical Detection for Focal-Plane Detector Protection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing protective devices for detectors in seeker heads or reconnaissance devices are limited in arrangement options, leading to defocusing and defocus errors when positioned to limit high-intensity radiation, compromising imaging quality and detector integrity.

Innovation Solution

A device with a phase element for wavefront coding, positioned in the focal plane, encodes radiation to allow decoding by a control device, ensuring reliable triggering of a protective device in the focal plane while maintaining imaging quality by compensating for defocus errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the protective device is arranged in the image plane to limit high-intensity radiation, then the detector is protected from damage, but the detector cannot be arranged in the image plane leading to defocusing and defocus error

Engineering Contradiction:
Improvedetector protectionVSAvoidimaging quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The image plane is functionally segmented into two distinct planes: the focal plane where the protective device is positioned to experience maximum radiation intensity for effective protection, and the detector plane where the detector is positioned downstream to receive the protected radiation. This segmentation allows each component to be optimally positioned for its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The protective device acts as an intermediary element positioned in the focal plane between the optical element and the detector. It mediates the radiation by limiting high-intensity radiation through nonlinear optical effects while allowing lower intensity radiation to pass through to the detector, thus protecting the detector while maintaining imaging functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the protective device is arranged in the focal plane to experience highest radiation intensity, then radiation limitation is effective, but the detector cannot be positioned in the focal plane causing defocus error

Engineering Contradiction:
Improveradiation intensity limitationVSAvoidimaging precision
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The solution transitions from a single-plane configuration to a multi-plane configuration along the optical axis. The protective device is positioned in the focal plane while the detector is positioned in a downstream detector plane, creating a spatial separation along the optical axis dimension. This dimensional change allows both components to be optimally positioned for their respective functions.

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

Solution Approach 2:

The protective device performs preliminary action by limiting high-intensity radiation in the focal plane before the radiation reaches the detector plane. This preliminary protection ensures that the detector is exposed only to safe radiation levels while maintaining the integrity of the imaging process.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the detector is positioned downstream of the protective device, then the protective device can be arranged in the focal plane, but defocusing occurs without wavefront coding

Engineering Contradiction:
Improveprotective device positioningVSAvoidimage focus
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

A phase element is introduced to modify the wavefront parameters of the radiation. By encoding the wavefront with specific phase modifications, the system changes the propagation characteristics of the radiation, enabling the detector to receive properly focused information despite being positioned downstream from the focal plane where the protective device is located.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The solution replaces traditional mechanical focusing mechanisms with wavefront coding and algorithmic decoding. Instead of mechanically adjusting the detector position to achieve focus, the system uses phase element encoding and computational decoding to restore image quality, enabling the detector to be positioned downstream while maintaining imaging 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

Enables reliable protection of detectors from high-intensity radiation without defocusing, allowing continued target tracking and image clarity, even under dazzling conditions.

Implementation Method 1

The optical element comprises a phase element for wavefront coding the radiation

Methodology Applied
Scientific EffectWavefront coding:

Implementation Method 2

nonlinear optical elements are used that limit the passage of radiation based on a nonlinear optical effect

Methodology Applied
Scientific EffectNonlinear optical effect:

Implementation Method 3

a focusing optical element which is designed to focus radiation passing through the optical element in a focal plane

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentEP4246206B1Aircraft, missile or active agent
Publication Date: 2025.09.03 DIEHL DEFENCE GMBH & CO KG
  • EP4246206B1 patent drawingFigure 1

AI summary

Device (1) for optical detection of a target object, comprising a focusing optical element (2) configured to focus radiation (3) passing through the optical element in a focal plane (4), a protective device (7) arranged in the focal plane (4) configured to absorb radiation (3) depending on a radiation parameter, in particular an irradiance, and a detector device (5) arranged in a detector plane (6) arranged in the beam path of the device (1) after the protective device (7), wherein a phase element (9) is provided between the optical element (2) and the focal plane (4), in particular on the optical element (2) or as part of the optical element (2), for wavefront coding of the radiation (3), which wavefront coding can be decoded by means of a control device (8) of the device (1).