4 Steps to Choose a Suitable Infrared Athermalized Lens

In the field of infrared optics, choosing a suitable infrared athermalized lens is a crucial task. Here are some important factors to consider:

Here is content list:

• I. Understanding the Basic Parameters of Infrared Athermalized Lens

• 2. Requirements for different application scenarios of Infrared Athermalized lens

I. Understanding the Basic Parameters of Infrared Athermalized Lens

1. Focal Length
   Focal length refers to the distance from the lens to the focal point, usually measured in millimeters (mm). It directly affects the field of view and magnification of the lens. For example, a shorter focal length will result in a wider field of view but lower magnification, while a longer focal length will lead to a narrower field of view but higher magnification. In practical applications, if you need to monitor a vast area, such as security monitoring of a large warehouse or large-scale environmental monitoring, you may prefer a lens with a shorter focal length to obtain a wider view. However, if you want to observe small targets at a distance, like monitoring wild animals in the distance or small components of industrial equipment, a lens with a longer focal length would be more appropriate.
   
   
2. F/# (F-number)
   F/# is a parameter used to indicate the aperture size of the lens, also known as the aperture ratio. It is the ratio of the focal length to the effective aperture diameter, usually expressed in the form of F/1.x. A smaller F/# value means a larger aperture opening, allowing for a higher amount of light transmission. In low-light conditions, such as security monitoring at night, a lens with a smaller F/# value can capture more light, thus obtaining clearer images. This is because more light entering the lens helps improve the brightness and contrast of the images when there is insufficient light.
   
   
3. Minimum Focus Distance
   The minimum focus distance is the closest distance at which the lens can focus on an object. A smaller minimum focus distance means that the lens can photograph closer objects. In industrial inspection, this parameter is very important. For example, when performing thermal analysis on circuit boards or checking for tiny damages in pipelines, the lens needs to be able to focus on objects at a close distance so as to discover potential fault points.
   
   
4. Field of View (FOV)
   The field of view refers to the range of view that the lens can capture, expressed in degrees or radians. A larger field of view means that the lens can capture a wider area. In environmental monitoring scenarios, such as fire warning monitoring of a forest or gas leak detection in a large industrial park, a lens with a larger field of view can cover a larger area, thus more effectively detecting abnormal situations.

II. Considering the Requirements of Different Application Scenarios

1. Thermal Imaging Applications
   Infrared athermalized lens are widely used in thermal imaging technology. They can capture and measure the infrared radiated heat of objects for detection, monitoring, and identification of heat distribution, temperature differences, and hidden objects. For example, in building insulation inspection, the lens can display the heat dissipation situation of different parts of the building through thermal imaging, helping to evaluate the insulation effect. For this kind of application, the focal length and field of view need to be considered comprehensively according to the size and distance of the inspected object to ensure that the thermal information of the object can be obtained completely. Meanwhile, the F/# and minimum focus distance will also affect the quality of thermal imaging and the ability to capture details.
   
   
2. Security Monitoring Applications
   In the field of security monitoring, especially in low-light or night situations, infrared athermalized lens play an important role. By capturing the infrared radiation of targets, they can provide surveillance images in dark environments for detecting and tracking people, vehicles, etc. When installing a surveillance system, if the monitored area is a long and narrow passage, such as a corridor or a street, you may need to choose a lens with an appropriate focal length and field of view to ensure that the activities in the passage can be clearly captured. For monitoring a large open area like a parking lot or a square, a lens with a larger field of view would be more suitable. Meanwhile, the F/# value also needs to be considered to ensure that enough light can enter the lens to obtain clear images at night.
   
   
3. Environmental Monitoring Applications
   Infrared athermalized lens can be used for environmental monitoring and measurement, such as fire warning, gas leak detection, temperature measurement, etc. Since infrared radiation is very sensitive to detecting abnormal temperatures, hot spots, and heat sources, it can meet various environmental monitoring needs. In a fire warning system, the lens needs to have a large field of view to cover a large area of forest or building area, and the F/# value should be appropriate to ensure that possible fire hot spots can be effectively captured under different weather and lighting conditions. For gas leak detection, besides the field of view, the minimum focus distance is also important because the lens may need to be able to focus on the leak source at a close distance for accurate detection.
   
   
4. Industrial Testing and Non-Destructive Testing Applications
   In the industrial field, infrared athermalized lens can be used for fault diagnosis of industrial equipment, thermal analysis of circuit boards, detection of pipelines and hidden damages. Through thermal imaging technology, potential problems can be discovered in time, and the efficiency of industrial production and equipment maintenance can be improved. When diagnosing faults of industrial equipment, the focal length may need to be selected according to the size of the equipment and the position of the components to be inspected. For example, for a large generator set, a lens with a longer focal length may be needed to observe the temperature conditions of key internal components; while for small electronic devices, a lens with a shorter focal length and a smaller minimum focus distance may be more convenient for inspecting tiny components on the circuit board.