Acta Photonica Sinica, Volume. 43, Issue 3, 322003(2014)
Optical Design of A two-way Switched Descend Camera
A new descent camera which used for deep space explorartion was designed. This camera can explore different distance targets by opening and closing the first optical lens. With the first optical lens in the optical path, the objective was focused for objects at distances ranging from 1.5 m to infinity. In this mode, the camera can take full-color pictures (spectral bandwidth 420~900 nm) of the cytaster surface. With it removed, the camera was focused at an object distance of 30 cm. In this mode, three lights of different wavelengths which were blue-green, red, and NIR were used independently to illuminate the close range objects and the camera can take multispectral pictures of the explored objects. This camera have a focal ratio f/5.4 and project a square field of view 49.5°×49.5° on the CCD. When at the infinity mode (with the first optical lens), the focal length is 12.9 mm and when at the close-up mode (without the first optical lens), the focal lenth is 12.5 mm. The first optical lens of the descent camera is a meniscus lens and it almost have no focal power. So the system focal changes lightly no matter with or without this lens. By this way, the drawback of a traditional two-way switch system that detected objects easily be lost when modes shift can be easily overcome. The design result show that the Modulation Transfer Function is higher than 0.6 in full-field at 35 lp/mm. The distortion of the system in full-field is better than 1.2%. Tilt and decenter tolerance of the first lens also have a reasonable result.
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Lv Juan, YANG Jian-feng, HE Ying-hong, MA Xiao-long, XUE Bin. Optical Design of A two-way Switched Descend Camera[J]. Acta Photonica Sinica, 2014, 43(3): 322003
Received: Jul. 8, 2013
Accepted: --
Published Online: Apr. 9, 2014
The Author Email: Juan Lv (lvjuan_24_cathy@163.com)