In modern infrared imaging systems, while the core detector of an infrared camera is important, it is the optical lens that ultimately determines the imaging quality and performance ceiling of the system. A high-performance infrared lens can maximize the potential of the detector, ensuring you capture the clearest and most accurate thermal data.

This article delves into several key technical parameters that must be considered when selecting an infrared optical lens, helping you make more informed decisions for your next project.

1. Core Wavelength: The Lens's "Working Domain"

The fundamental difference between infrared optics and visible-light optics lies in their operating wavelength bands. Different application scenarios rely on different atmospheric windows:

Short-Wave Infrared (SWIR, 1–3μm): Commonly used in semiconductor inspection, material sorting, and laser spot analysis.

Mid-Wave Infrared (MWIR, 3–5μm): The primary band for thermal imaging, suitable for temperature measurement, power equipment inspection, industrial predictive maintenance, gas leak detection, and high-end military applications.

Long-Wave Infrared (LWIR, 8–14μm): Also widely used in thermal imaging, particularly in security surveillance, firefighting, autonomous driving, and medical diagnostics.

Wuhan Clear Technology Advantage: Wuhan Clear Technology Co., Ltd. offers a comprehensive product line covering SWIR, MWIR, and LWIR bands. We provide customized optical design solutions tailored to your specific wavelength requirements, ensuring optimal transmittance and imaging performance within the target band.

2. Focal Length and Field of View (FOV): Balancing "Overview" and "Detail"

Focal Length: Determines the magnification and field of view of the lens. A short focal length provides a wide field of view, ideal for large-area monitoring, while a long focal length offers a narrow field of view and high magnification, suitable for long-distance observation.

Field of View (FOV): Directly related to focal length. Selecting a lens involves balancing "how much you can see" (wide FOV) and "how far you can see clearly" (long focal length).

Solution: In addition to fixed-focal-length lenses, Wuhan Clear Technology offers a variety of motorized zoom lenses and continuous zoom lenses, enabling users to seamlessly switch between wide-angle search and long-distance detailed observation without changing lenses. This significantly enhances device flexibility and adaptability to various scenarios.

3. F-Number: The Lens's "Light-Gathering Ability"

The F-number (aperture value) is the ratio of the focal length to the entrance pupil diameter. It directly affects the lens's light throughput and depth of field.Low F-Number (e.g., F/1.0): Indicates greater light throughput, allowing for clearer images in darker thermal environments or enabling the use of detectors with smaller pixels. However, it may result in a shallower depth of field and more challenging optical aberrations. High F-Number (e.g., F/2.0): Reduces light throughput but offers a larger depth of field and easier control of aberrations.

Our Technology: Leveraging advanced optical design and precision manufacturing capabilities, Wuhan Clear Technology has successfully developed a series of high-end lenses with large apertures and low F-numbers (e.g., F/1.0). These lenses ensure excellent thermal sensitivity while effectively correcting aberrations through technologies such as aspherical and diffractive optical elements (DOE), achieving high-resolution imaging with large apertures.

4. Resolution and MTF: The Standards for Measuring "Clarity"

Resolution refers to the lens's ability to resolve details, often objectively evaluated using the Modulation Transfer Function (MTF). The MTF curve describes the lens's ability to transmit contrast at different spatial frequencies.

Key Metric: The lens's resolution must match the pixel size of the detector to avoid wasting detector performance. An optimal design ensures the lens's cutoff frequency exceeds the detector's Nyquist frequency. Wuhan Clear Technology's "matching design" philosophy ensures our lenses are perfectly compatible with mainstream detector models, fully leveraging the value of every detector pixel.

5. Cold Shield Efficiency: A "Unique Metric" for Thermal Imaging

This is a unique and critical metric for infrared thermal imaging systems, measuring the lens's ability to suppress its own stray radiation. Consequences of Low Efficiency (<100%): Thermal radiation from the lens barrel and internal components can directly reach the detector, creating uneven "ghosting" or "hot spots" that severely干扰 real thermal images. This can lead to significant errors, especially when measuring temperatures near room temperature.

100% Cold Shield Efficiency: The ideal state, meaning only thermal radiation from the target scene reaches the detector.

Wuhan Clear Technology employs unique cold shield matching design and internal stray radiation suppression techniques, ensuring our lenses' cold shield efficiency approaches 100%. This effectively eliminates interference from the system's own thermal radiation, providing clean, reliable thermal images and accurate temperature measurement data.

6. Conclusion: Your Optimal Partner in System Engineering

Choosing an infrared lens involves more than just selecting a single parameter. It requires a comprehensive consideration of the entire imaging system's needs (detector, application environment, cost, etc.). Wuhan Clear Technology is not just an optical manufacturer but also your trusted technical partner. With deep expertise in optical design, materials science, precision manufacturing, and coating technology, we offer everything from standard products to fully customized infrared optical solutions.

Visit the official website of Wuhan Clear Technology Co., Ltd. or contact our technical team. Let our professional optical expertise provide the "clear vision" for your infrared imaging system.