Design and development of bi-directional Viewer

Bi-directional viewer just likes a lens of camera. Unlike conventional camera lens, the bi-directional viewer captures not only front view but also side view around the bi-directional viewer. The barrel of bi-directional viewer was designed to have cuts in the side to allow side light to come through, and we use two aspherical mirrors to receive and change the side light to converge on the main optical path. The front view and side view can be imaged simultaneously on an image sensor. Commercial aspherized achromatic lens and micro video lens were also used to keep the image quality and miniaturize the size of the bi-directional viewer respectively. We report on the development of bi-directional viewer, including optical design, optical simulation, optomechanics design, fabrication techniques, assembly procedure and performance testing. The MTF of the bi-directional viewer is also measured and discussed in this paper. We successfully design and realize a bi-directional viewer, which can perform 100 lp/mm spatial frequency image in detail above 20% contrast in the 7.6 mm front view area. And we keep the dimensions of this device within 35 mm in total length and phi 20 mm in diameter.