Robert G. Batchko

Fluidic lens with reduced optical aberration

We present an electrically-actuated adaptive fluidic lens having a 10-mm aperture, 4-diopter range and center-thickness less than 1 mm. The lens employs dual deflectable glass membranes encasing an optical fluid. A piezoelectric ring bender actuator draws less than 1 mW and is built into the 25-mm-diameter lens housing. The adaptive lens demonstrates resolution comparable to commercial precision glass singlet lenses of similar format over a wide range of field angles and focal powers. Focal power vs. voltage, resolution, modulation transfer function (MTF), life testing and dynamic response are examined and show that the lens is suitable for numerous adaptive lens applications demanding high optical quality.

Liquid crystal based active optics

Liquid crystal spatial light modulators, lenses, and bandpass filters are becoming increasingly capable as material and electronics development continues to improve device performance and reduce fabrication costs. These devices are being utilized in a number of imaging applications in order to improve the performance and flexibility of the system while simultaneously reducing the size and weight compared to a conventional lens. We will present recent progress at Sandia National Laboratories in developing foveated imaging, active optical (aka nonmechanical) zoom, and enhanced multi-spectral imaging systems using liquid crystal devices.

A variable-collimation display system

Two important human depth cues are accommodation and vergence. Normally, the eyes accommodate and converge or diverge in tandem; changes in viewing distance cause the eyes to simultaneously adjust both focus and orientation. However, ambiguity between accommodation and vergence cues is a well-known limitation in many stereoscopic display technologies. This limitation also arises in state-of-the-art full-flight simulator displays. In current full-flight simulators, the out-the-window (OTW) display (i.e., the front cockpit window display) employs a fixed collimated display technology which allows the pilot and copilot to perceive the OTW training scene without angular errors or distortions; however, accommodation and vergence cues are limited to fixed ranges (e.g., ~ 20 m). While this approach works well for long-range, the ambiguity of depth cues at shorter range hinders the pilot’s ability to gauge distances in critical maneuvers such as vertical take-off and landing (VTOL). This is the first in a series of papers on a novel, variable-collimation display (VCD) technology that is being developed under NAVY SBIR Topic N121-041 funding. The proposed VCD will integrate with rotary-wing and vertical take-off and landing simulators and provide accurate accommodation and vergence cues for distances ranging from approximately 3 m outside the chin window to ~ 20 m. A display that offers dynamic accommodation and vergence could improve pilot safety and training, and impact other applications presently limited by lack of these depth cues.

Large-Format Tunable Fluidic Lenses for High-Resolution Rapid Focusing

We present optical analysis of electrically-actuated adaptive fluidic lenses having apertures of 10 mm and 40 mm. Zernike decomposition and resolution testing is presented for the 10-mm aperture lens. Focal power and imaging resolution characteristics of the 40-mm aperture lens are provided. The data for the lenses show both formats are suitable for numerous adaptive lens applications demanding high optical quality.