Development of a fast aperture, high resolution, wide-angle, optically passive athermalized LWIR lens for driver vision enhancer systems

Abstract

This paper presents the design of a fast aperture, high resolution, wide-angle, optically passive athermalized long-wave infrared (LWIR) lens suitable for driver vision enhancer systems. The growing demand in high resolution thermal imaging has led to the need for advanced lens designs that can deliver exceptional performance in this electromagnetic spectrum. The proposed lens design focuses on achieving a fast aperture, which is crucial for capturing object details in modern bolometer arrays with smaller pixel pitch. Additionally, the design provides a wide-angle field of view to enable comprehensive scene coverage. The use of optical passive athermalization technique also ensures that the lens maintain its performance across a wide range of operating temperatures, thereby eliminating the need for any active temperature compensation mechanisms. In order to achieve a large image diameter, the lens design incorporates aspheric and diffractive surfaces, as well as a combination between conventional and chalcogenide materials. These elements help to minimize optical aberrations and increase image sharpness. With the use of computer-aided design software and its corresponding optical simulation tools, the design was refined to meet the desired specifications, including resolution, field of view and athermalization requirements. The resulting lens design managed to achieve a horizontal field of view of 76 degrees with a fast aperture of F1.0 for an uncooled 12-micron SXGA detector. This design ensures consistent and nearly diffraction-limited performance in diverse operating conditions, making it suitable for driver vision enhancer systems, as well as the general automotive applications.