ABSTRACT
We present the development of a compact (about 1.3 × 2.0 × 20 mm3) freeform optical lightguide for sensing applications, from the conceptual design to the fabrication through injection molding. The design of the optic is based on the flow-line method from Nonimaging Optics, which allows the desired optical functionalities (45° half-acceptance and 40° beam steering) while meeting particularly tight mechanical and geometrical constraints. An extensive analysis of the effects of fabrication parameters on the performances demonstrates the importance of minimizing the fillet radius. This requisite inspired a special procedure for designing the mold, which is built as a "3D puzzle" assembly of separate pieces, each one dedicated to one specific side surface of the lightguide. This technique enables uniform optical quality on all the optic's surfaces and removes the need of a fillet radius in the mold. At present, the first lightguide prototypes have been fabricated; after the coating phase, they will be ready for the validation stage.
ABSTRACT
In conventional multichannel imaging systems, all channels have similar imaging properties [field-of-view (FOV) and angular resolution]. In our approach, channels are designed to have different imaging properties which add multiresolution capability to the system. We have experimentally demonstrated, for the first time to our knowledge, a three-channel imaging system which simultaneously captures multiple images having different magnifications and FOVs on an image sensor. Each channel consists of four aspherical lens surfaces fabricated from four PMMA plates by ultraprecision diamond tooling and of a baffle made from a titanium (Ti) and aluminum (Al) based metal alloy. The integrated imaging system is able to record a FOV of 7.6° with the first channel and 73° with the third channel while having a magnification ratio of about 6 between them. The experimental and simulation results, specifically the FOV and magnification ratios, are comparable, and this paves a way for low-cost, compact imaging systems which can embed smart imaging functionalities.
