In order to solve the problem of high-cost of the vehicle-assisted driving system and satisfy the requirements of highimaging-quality, the vehicle-mounted infrared optics is light, small, low-cost and mass-produced. In this paper, a compact single-piece free-from prism is used to achieve in-vehicle thermal imaging optical system with waveband of 8~12um, field-of-view of ±14°×±10.5°, F-number of 1 and focal length of 16mm. The optics has a compact structure similar to two-mirror off-axis system, and has the same characteristics with refractive optics of high-quality and low difficulty in installation. Through the process improvement method, the use of molding technology can further reduce the cost of lens, especially suitable for large-volume small-aperture optical systems.
Off-axis reflective optics, due to its no chromatic, no obscuration, small size, compact structure, easy to achieve wide field of view(FOV), high-quality imaging and other features, are widely concerned. In this paper, the conformal ellipsoidal dome of MgF2 material is used to allay the air resistance and reduce the aerodynamic heating effect of the missile head. The compact off-axis four-mirror is used to realize a conformal optical system of the seeker with medium wave infrared(MWIR)，which the working waveband is 3~5μm, F number is 2, FOV is ±1 degree and the focal length is 55mm. The optics achieve 100% cold aperture efficiency and the MTF value of each field at 17lp/mm is greater than 0.7. It has a working distance of 17.4mm and a sapphire window 14.7mm apart from the focal plane, leaving plenty of room for the refrigerant detector. This system can also meet the high accuracy positioning with imaging quality requirements and ensure light design of the seeker.
In order to improve the detection accuracy and range of new generation of Forward Looking Infra-Red (FLIR) system for distant targets, its optical system, which usually consists of a fore afocal telescope and rear imaging lenses, is required to has wide spectral range, large entrance pupil aperture, and wide field of view (FOV). In this paper, a new afocal Three-Mirror Anastigmat (TMA) with widened field of view and high demagnification is suggested. Its mechanical structure remains coaxial, but it has zigzag optical axis through properly and slightly decentering and tilting of the three mirrors to avoid its secondary obscuration due to the third mirror as FOV increase. Compared with conventional off-axis TMA, the suggested zigzag-axis TMA is compact, easy-alignment and low-cost.
The design method and optimum result of the suggested afocal TMA is presented. Its initial structural parameters are determined with its first-order relationship and primary aberration theory. Slight and proper decentration and tilt of each mirror is leaded in optimization so that its coaxial mechanical structure is held but attainable FOV and demagnification are respectively as wide and as high as possible. As an example, a 5.5-demagnification zigzag-axis afocal TMA with a wavelength range, an entrance pupil diameter, and FOV respectively from 3μm to 12μm, of 320mm, and 2×3.2 degrees and with a real exit pupil, is designed. Its imaging quality is diffraction limited. It is suitable for fore afocal telescope of the so-called third generation FLIR.