An integral imaging method based on microscanning of a microlens array is proposed. The effects of microscanning on the depth resolution and the product of depth of focus and lateral resolution squared (PDLRS) of an integral imaging system are quantitatively analyzed. Calculation results show that microscanning can improve not only the depth resolution, but the PDLRS can be increased. The amoun...

A dielectric liquid microlens with a well-shaped electrode is demonstrated. The bottom well-shaped electrode and the top planar electrode induce an inhomogeneous electric field when a voltage is applied, which causes the focal length to change. Adaptive microlenses and microlens arrays with well-shaped electrode are fabricated and their performance is evaluated. The bi-convex structure introduc...

Light focused from air into a spherical microlens is affected by diffraction at the lens surface as its diameter approaches the wavelength of light. Through an extension of Mie theory, we show that a converging wave that is incident upon a Si microlens with a diameter less than approximately 4lambda creates a spot as much as 25% smaller than predicted with vector diffraction theory. Si microlen...

A two step process has been developed for the fabrication of diffraction limited concave microlens arrays. The process is based on the photoresist filling of melted holes obtained by a preliminary photolithography step. The quality of these microlenses has been tested in a Mach-Zehnder interferometer. The method allows the fabrication of concave microlens arrays with diffraction limited optical...

The recent rapid development in microlens technology has provided many opportunities for miniaturized optical systems, and has found a wide range of applications. Of these microlenses, tunable-focus microlenses are of special interest as their focal lengths can be tuned using micro-scale actuators integrated with the lens structure. Realization of such tunable microlens generally relies on the ...

In this paper, the efficiency and uniformity improvement of non-image LED illumination system with collimator, microlens array and condenser are proposed for pico-projector. The LED light is collimated to 18 degree with efficiency 99.36% by collimator. For image uniformity and flux efficiency, the doule-side microlens array and two condensers are adopted to form a homogenizer. With this homogen...

We demonstrate subwavelength spatial resolution with a scanning microlens operating in collection mode with a large-area detector. Optical contrast is created by refraction of off-axis light rays at angles larger than the maximum collection angle. With a microfabricated silicon microlens 10 mm in diameter, we measure spatial resolution due to refraction contrast of l/4.3 at a wavelength of l510...

We use a conventional and straightforward route to fabricate scalable morphology-controlled regular structures. This route is based on the etching of PDMS microlens array in CF4 and CF4/O2 plasma. PDMS microlens array can be changed to regularly isolated microdot structures array in CF4 plasma. Microbowl shaped structures array can be reached in CF4/O2 plasma. Moreover, a set of structures afte...

We present a method to design binary diffractive microlenses with subwavelength structures, based on the finite-difference time-domain method and the genetic algorithm, also accounting for limitations on feature size and aspect ratio imposed by fabrication. The focusing efficiency of the microlens designed by this method is close to that of the convex lens and much higher than that of the binar...