Chirped arrays of refractive ellipsoidal microlenses for aberration correction under oblique incidence

Abstract

Improvements of the resolution homogeneity of an ultra-thin artificial apposition compound eye objective are accomplished by the use of a chirped array of ellipsoidal micro-lenses. The array contains 130x130 individually shaped ellipsoidal lenses for channel-wise correction of astigmastism and field curvature occurring under oblique incidence. We present an analytical approach for designing anamorphic micro-lenses for such purpose based on Gullstrands equations and experimentally validate the improvement. Considerations for the design of the photolithographical masks for the micro-lens array fabrication by melting of photoresist cylinders with ellipsoidal basis are presented. Measurements of the optically performance are proceed on first realized artificial compound eye prototypes showing a significant improvement of angular resolution homogeneity over the complete field of view of 64.3?.

Wafer-Level Hybrid Integration of Complex Micro-Optical Modules

“…In other words: every lenslet on the wafer can be designed to have its own position, orientation, size (mask #1), and focal length (mask #2). We used this enhanced design freedom in the randomization of arrays for homogenization [17], the channel-wise aberration correction of multichannel imaging optics [18] or simply the lateral arrangement of elements with different parameters on the same wafer [19]. A means to simulate -generalized‖ chirped or stochastic lens arrays in the ray tracing design and routines to calculate the corresponding mask data for each lenslet were implemented in our fabrication process [20].…”

Curved artificial compound-eyes for autonomous navigation

“…The foci are not at the photoreceptor plane and cause the well-defined blurring for optics flow detection. It spans the extended FOV along a column due to the use of a microlens array with toroidal-shaped lenslets and a deviant pitch compared to the photoreceptors [22]. The pitch difference between microlens (290 µm) and photoreceptor arrays (260 µm) lead to off-axis paths.…”

Generalized refraction using lenslet arrays

“…1 shows examples of such generalized CLAs. Manufacturing such generalized CLAs will require a significant extension of current techniques for manufacturing complex microlens arrays [27,28]. From now on, we will usually drop the adjective "generalized" and simply refer to CLAs.…”