Athermalized Infrared Lens Acceptance: Define Soak, Refocus and Image Criteria

OPTICS · TECHNICAL INSIGHT

An athermalized infrared lens needs an explicit temperature-test procedure. Define stabilization, focus adjustment and image-quality criteria together so the test can distinguish passive focus stability from a result obtained by refocusing.

Reference and scope

This is an original TUOLAN technical insight supported by the official technical reference linked below. It is not a new product announcement. The application recommendations are TUOLAN’s analysis; supplier examples are not TUOLAN performance guarantees.

Thermal behavior belongs to the assembled system

Edmund Optics’s passive-athermalization note explains the importance of material expansion and refractive-index change with temperature, particularly in infrared designs. These principles do not establish a temperature range for an unrelated lens.

For infrared imaging lens sourcing, specify SWIR, MWIR or LWIR explicitly and identify the detector, sensor plane and mounting interface. Include the intended working distance and focus state. Do not transfer a thermal result between bands or camera configurations.

Write the no-refocus rule into the test

If the design relies on passive stability, state whether any manual or motorized focus adjustment is allowed during the temperature sequence. Set the initial focus condition and record it before changing temperature. Keep the image criterion consistent at all agreed test points.

For a system that intentionally refocuses, define a separate test for focus recovery, including the control method and time needed to obtain a usable image. A refocused result answers a different question from an unchanged-focus result.

Record stabilization and repeatability

Agree how the thermal state is judged stable, where temperature is measured and how long the assembly is held before imaging. Review warm-up and thermal gradients when relevant. Use a representative mount and detector configuration rather than testing a loose optic alone.

The KI610011 athermalized LWIR configuration is a product-specific review starting point; request its current drawing and verified test conditions before adopting it. No temperature range or thermal performance is inferred here. Approval should connect a defined thermal procedure with an agreed image result.

Buyer RFQ checklist

• Identify band, detector, mount, working distance and initial focus.
• Separate unchanged-focus testing from allowed refocus testing.
• Agree stabilization criteria and record temperature at each image test.

Sources

Official company source, Technical reference; publication date not stated. Reviewed 14 October 2026. Checked on 14 October 2026. Buyer recommendations are TUOLAN’s analysis, separate from the source announcement.

Edited and analysed by TUOLAN TRADE.