Development of compact optical zoom lenses with extended-depth-of-field

Abstract

Development of compact optical zoom lenses for integration in mobile phones is the goal of many companies. Optical zoom lenses change their focal length by the movement of lens elements or change in surface curvature or refractive index and this complicates the zoom lens design. Extended depth-of-field (EDOF) techniques provides the mean to simplify and miniaturize zoom lens designs with moving lens elements and a new EDOF optimization technique is presented. Finally, the starting point and an example of a compact optical zoom lens design with EDOF is also described.

A novel two- and multi-level binary phase mask design for enhanced depth-of-focus

“…Implementation of the cubic and generalized cubic phase mask for WFC and with computational deblurring can be seen: for visual waveband in [3], [4], for low-infrared (LWIR) in [5], for near-infrared (NIR) with athermalization in [6], for LWIR with athermalization in [7]. Application of generalized cubic phase mask for design of zoom systems for visual waveband is a topic of papers [8], [9], [10], [11], [12]. A wide variety of different types of phase masks have been studied in order to increase the depth of field: cubic and generalized cubic [3], [4] logarithmic [13], exponential [14], hyperbolic [15], square-root [16], etc.…”

“…Of course even larger value can be taken for this low bound of min Ψ P SN R but there is a risk that there is no solution for (9). The BPM component in (2) depends on the design wavelength λ o and the image wavelengths λ.…”

“…Three parameters control the results of this design: the minimal width of the piece-wise invariant segments calculated as m w − 1, the phase range of the mask defined by the order m 0 and the maximal number of levels N . These parameters are the variables of optimization in (9).…”