Infrared Camera Continuous Optical Zoom TPC Integration

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Solution Overview

Problem

Current passive infrared imaging systems face challenges in achieving a balanced design that optimizes range, cost, ergonomics, and size, particularly in transitioning between Large Field (GC) and Small Field (PC) zoom configurations while incorporating a Very Small Field (TPC) optical configuration without increasing weight, cost, or complexity.

Innovation Solution

The system employs a continuous infrared zoom with two moving groups, where the TPC configuration operates at a reduced aperture with a hot pupil imaged near the cold pupil of the continuous zoom, utilizing the support of a zoom head group lens as the aperture diaphragm and maintaining a non-dedicated mechanism for aperture adjustment, ensuring the optical components are not oversized for the TPC function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a TPC configuration is added to achieve extended range, then the imaging capability is improved, but the weight and bulk of the system increase

Engineering Contradiction:
Improveimaging capabilityVSAvoidsystem weight
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent combines the TPC configuration with the existing continuous zoom lens by using the support of one of the lenses in the head group as the aperture diaphragm for TPC. This merging approach allows the TPC function to be integrated into the existing optical structure without adding separate heavy components, thereby improving imaging capability while avoiding additional weight and bulk

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent makes the lens support structure serve multiple functions: it acts as both the mechanical support for the lens and the aperture diaphragm for the TPC configuration. This multi-functionality eliminates the need for separate aperture mechanisms, reducing system complexity and weight while maintaining the desired imaging performance

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

2Measurement precision

If a TPC configuration is added to achieve extended range, then the imaging capability is improved, but the cost of the system increases

Engineering Contradiction:
Improveimaging capabilityVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the TPC aperture function with the existing lens support structure, eliminating the need for separate aperture diaphragms and their associated mechanisms. This integration reduces the number of components that need to be manufactured and assembled, thereby reducing production costs while maintaining enhanced imaging capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

By making the lens support serve as the aperture diaphragm for TPC, the patent creates a multi-functional component that reduces overall system complexity. This approach decreases manufacturing steps and assembly operations, leading to lower production costs without sacrificing the improved imaging performance

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

3Measurement precision

If the aperture is reduced for TPC configuration, then the photometric performance is improved, but the amount of structure flux increases

Engineering Contradiction:
Improvephotometric performanceVSAvoidstructure flux
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent acknowledges that reduced aperture increases structure flux, but converts this potential harm into a benefit by using the lens support as the aperture diaphragm. This approach provides photometric control while the structure flux can be managed through the designed aperture geometry, transforming the harmful effect into an acceptable trade-off for achieving the desired photometric performance

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 approach allows for an integrated TPC configuration that is photometrically controlled without significant additional cost, maintaining performance and reducing the need for oversized components, thus addressing the limitations of existing systems in mass, bulk, cost, and ergonomics.

Implementation Method 1

an opto-mechanical image formation device with variable focal length also referred to as optical zoom

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3523957B1Infrared camera with continuous optical zoom and incorporated extender
Publication Date: 2020.07.29 THALES SA
  • EP3523957B1 patent drawingFigure 1A~1B
  • EP3523957B1 patent drawingFigure 2A~2C
  • EP3523957B1 patent drawingFigure 3A~3C

AI summary

The invention relates to a passive IR imaging system, comprising: - a matrix detector (1) in a cryostat with a cold diaphragm (3), - an image formation device, with focal length continuously variable from FGC to FPC having, within the range of focal lengths, a constant digital aperture and an aperture diaphragm at the cold diaphragm, comprising: ⋅ a head group (Gf1) having a fixed position and constant focal length, having at least one lens in a holding mechanism (5) by the PC configuration, ⋅ a first and second movable group positioned to ensure the change of focal length between FGC and FPC as well as the focusing of the image, ⋅ an image transport group (Gf2) with fixed position and constant magnification, capable of imaging the aperture diaphragm in order to limit the diameter of the useful PC beams on the lenses of the head group. The device has a TPC configuration with the first and second movable groups positioned in order to obtain the focal length FTPC, and the aperture diaphragm of same produced in the holding mechanism.