Closed-Loop Joule-Thomson Cooler for Infrared Detection Circuits

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Solution Overview

Problem

Current cooled detection devices require high energy consumption due to inefficient cooling systems, with conventional coolers achieving an efficiency of only 8 to 10%, leading to suboptimal performance.

Innovation Solution

A cooled detection device is designed with a hybridized detection and read circuit configuration using different semiconductor substrates and a closed-loop Joule-Thomson cooler, which reduces energy consumption by optimizing the cooling process through a gas mixture and additive use, allowing operation between 77K and 200K.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a conventional cooling device is used to cool the detection circuit, then the detection circuit operates at low temperature to reduce electrical interference, but the cooling efficiency is only 8 to 10% and energy consumption is high

Engineering Contradiction:
Improvedetection circuit temperatureVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

A cold table is introduced as an intermediary thermal management component between the cooling device and the detection circuits. The cold table has high thermal conductivity and is thermally coupled to both the cooling device and multiple detection circuits, efficiently distributing cooling throughout the system. This intermediary structure improves overall cooling efficiency beyond the 8-10% achieved by conventional direct cooling approaches.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cold table serves multiple functions simultaneously: it acts as a thermal conductor to distribute cooling, provides mechanical support for mounting detection circuits and electronics, and creates a thermally isolated environment. This multi-functionality consolidates multiple components into one, improving energy efficiency by eliminating redundant cooling requirements for each individual circuit.

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

2Reliability

If multiple detection circuits are cooled individually, then each circuit can operate at optimal temperature, but the device complexity and energy consumption increase

Engineering Contradiction:
Improvedetection circuit performanceVSAvoidcooling system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple detection circuits are merged onto a single cold table that is thermally coupled to one cooling device. This consolidation allows all detection circuits to be cooled simultaneously through the high thermal conductivity of the cold table, reducing system complexity while maintaining optimal operating temperatures for each circuit. The cold table acts as a common thermal platform that efficiently distributes cooling to all mounted circuits.

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

The solution significantly reduces energy consumption and enhances performance by achieving efficient cooling within the specified temperature range, improving the overall efficiency of the detection device.

Implementation Method 1

The Joule-Thomson cooler utilizes Joule-Thomson expansion, performing a laminar and steady-state expansion of a pure gas or gas mixture within the cooler. This expansion is achieved by passing the gas stream through an expansion orifice 5. The expansion takes place in a thermally insulated environment to obtain isenthalpic expansion.

Methodology Applied
Scientific EffectJoule-Thomson expansion: Joule-Thomson Effect

Implementation Method 2

The detection circuit 1 includes at least one photodetector that converts an optical signal into an electrical signal

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentEP3114444B1Cooled detecting device
Publication Date: 2023.05.03 LYNRED
  • EP3114444B1 patent drawingFigure 1

AI summary

A device for detecting infrared radiation comprises a circuit (1) for detecting infrared radiation equipped with at least one photodetector. A read circuit (2) is electrically connected to the detecting circuit (1) and it is configured to process the signal emitted by the detecting circuit (1). A Joule-Thomson cooler cools a cold plate (3) thermally and mechanically connected to the detecting circuit (1) and to the read circuit (2). The cold plate (3) comprises an internal cavity (7) supplied with a gas mixture. An orifice (5) for expanding the gas mixture is placed at an inlet of the internal cavity (7). An outlet of a compressor (6) supplies the expansion orifice (5) with a gas mixture. The inlet of the compressor (6) receives the expanded gas mixture coming from an outlet of the internal cavity (7).