Abstract:
Miniaturization and athermalization design of uncooled long-wave infrared (LWIR) continuous zoom optical systems is difficult given the large relative aperture. The lightweight and miniaturization design of an LWIR continuous zoom optical system with an uncooled focal plane array detector for 640×512 pixels was realized by restraining the object lens size and total length of the system by using a variable diaphragm. Through reasonable material configuration and an active compensation method, the athermalization design of a continuous zoom optical system with a zoom ratio of 8.5 and five lenses was achieved. The system F number is constant at 1.2, the spectral range is 8 μm to 12 μm, the field of view (FOV) ranges from 30°×24° to 3.5°×2.8°, and the total length of the system is 187.5 mm. This optical system exhibits light weight, short total length, and high transmittance. Within the temperature range of -40℃ to +60℃, the optical system affords good image quality in the full field of view during zooming.