Selim Olcer

Light engine and optics for HELIUM3D auto-stereoscopic laser scanning display

This paper presents a laser-based auto-stereoscopic 3D display technique and a prototype utilizing a dual projector light engine. The solution described is able to form dynamic exit pupils under the control of a multi-user head-tracker. A prototype completed recently is able to provide a glasses-free solution for a single user at a fixed position. At the end of the prototyping phase it is expected to enable a multiple user interface with an integration of the pupil tracker and the spatial light modulator.

MEMS sensor array platform integrated with CMOS based optical readout

This paper reports a micro electro-mechanical system (MEMS) based sensor array integrated with CMOS-based optical readout. The integrated architecture has several unique features and reported here for the first time. MEMS devices are passive and there are no electrical connections to the MEMS sensor array. Thus the architecture is scalable to large array formats for parallel measurement applications and can even be made as a disposable cartridge in the future using self-aligning features. A CMOS-based readout integrated circuit (ROIC) is integrated to the MEMS chip. Via holes are defined on ROIC by customized post-processing to enable integrated optical readout. A diffraction grating interferometer-based optical readout is realized by pixel-level illumination of the MEMS chip through the via holes and by capturing the reflected light using a photodetector array on the CMOS chip.

Two-Dimensional MEMS Stage Integrated With Microlens Arrays for Laser Beam Steering

A novel microelectromechanical stage with one uniaxial set of combs capable of 2-D actuation is presented. A polymer microlens array (MLA) is mounted vertically onto the stage. Driven at resonance, the stage deflects 124 μm out of plane and 34 μm in plane. Finally, laser beam steering is demonstrated using two cascaded MLAs.

Rapid Alleviation of Parkinson's Disease Symptoms via Electrostimulation of Intrinsic Auricular Muscle Zones.

Background: Deep brain stimulation of the subthalamic nucleus (STN-DBS) and the pedunculopontine nucleus (PPN) significantly improve cardinal motor symptoms and postural instability and gait difficulty, respectively, in Parkinson’s disease (PD). Objective and Hypothesis: Intrinsic auricular muscle zones (IAMZs) allow the potential to simultaneously stimulate the C2 spinal nerve, the trigeminal nerve, the facial nerve, and sympathetic and parasympathetic nerves in addition to providing muscle feedback and control areas including the STN, the PPN and mesencephalic locomotor regions. Our aim was to observe the clinical responses to IAMZ stimulation in PD patients. Method: Unilateral stimulation of an IAMZ, which includes muscle fibers for proprioception, the facial nerve, and C2, trigeminal and autonomic nerve fibers, at 130 Hz was performed in a placebo- and sham-controlled, double-blinded, within design, two-armed study of 24 PD patients. Results: The results of the first arm (10 patients) of the present study demonstrated a substantial improvement in Unified Parkinson’s Disease Ratings Scale (UPDRS) motor scores due to 10 min of IAMZ electrostimulation (p = 0.0003, power: 0.99) compared to the placebo control (p = 0.130). A moderate to large clinical difference in the improvement in UPDRS motor scores was observed in the IAMZ electrostimulation group. The results of the second arm (14 patients) demonstrated significant improvements with dry needling (p = 0.011) and electrostimulation of the IAMZ (p < 0.001) but not with sham electrostimulation (p = 0.748). In addition, there was a significantly greater improvement in UPDRS motor scores in the IAMZ electrostimulation group compared to the IAMZ dry needling group (p < 0.001) and the sham electrostimulation (p < 0.001) groups. The improvement in UPDRS motor scores of the IAMZ electrostimulation group (ΔUPDRS = 5.29) reached moderate to high clinical significance, which was not the case for the dry needling group (ΔUPDRS = 1.54). In addition, both arms of the study demonstrated bilateral improvements in motor symptoms in response to unilateral IAMZ electrostimulation. Conclusion: The present study is the first demonstration of a potential role of IAMZ electrical stimulation in improving the clinical motor symptoms of PD patients in the short term.

MEMS Fourier transform IR spectrometer

A comb-actuated MEMS lamellar grating FTIR spectrometer with maximum OPD of 652μm and clear aperture area of 9.6mm² is developed. Laser and IR interferograms in 2.5–16μm wavelength band are acquired at ambient pressure.

Head Mounted Projection Display & Visual Attention: Visual Attentional Processing of Head Referenced Static and Dynamic Displays while in Motion and Standing

The Head Mounted Projection Display (HMPD) is a growing interest area in HCI. Although various aspects of HMPDs have been investigated, there is not enough information regarding the effect of HMPDs (i.e., head referenced static and dynamic displays while a user is in motion and standing) on visual attentional performance. For this purpose, we conducted a user study (N=18) with three experimental conditions (control, standing, walking) and two visual perceptual tasks (with dynamic and static displays). Significant differences between conditions were only found for the task with dynamic display; accuracy was lower in walking condition compared to the other two conditions. Our work contributes an empirical investigation of the effect of HMPDs on visual attentional performance by providing data-driven benchmarks for developing graphical user interface design guidelines for HMPDs.

48.4: Beam Forming for a Laser Based Auto-stereoscopic Multi-Viewer Display

Abstract An auto-stereoscopic back projection display using a RGB multi-emitter laser illumination source and micro-optics to provide a wider view is described. The laser optical properties and the speckle due to the optical system configuration and its diffusers are characterised . Index Terms : 3D Display, laser scanning, pupil tracking, auto-stereoscopic, laser display, laser speckle, light engine, backlight, liquid crystal, LCoS, microlens, diffuser . 1. Introduction The goal of this project is to develop a multi-viewer multi-user auto-stereoscopic display. The display is being developed within the European Union-funded HELIUM3D (High Efficiency Laser-based Multi-user Multi-modal 3D Display) project. The collaborators are University College London, De Montfort University, Koc University, Philips, Nanjing University, Barco, Fraunhofer HHI, and Technische Universiteit Eindhoven. The 3D laser based display consists of three subsections: a multi-user head-tracker, projection optics and transmission screen (which is called the transfer screen in this project) and a light engine, shown in Figure 1. The light engine produces time-multiplexed scanned views of the displayed image content. Three red, green and blue lasers are employed as the light sources and the laser beams are combined and shaped into a light line which is scanned across the surface of a Liquid Crystal on Silicon (LCoS) modulation device to form the image.

Miniaturized FR4 spectrometers

A miniaturized and electromagnetically driven FR4 based moving platform is developed for Fourier Transform spectrometer applications. Both Michelson interferometer and Lamellar Grating interferometer configurations are demonstrated. ±500 µm translational motion (corresponding to 5 cm−1 spectral resolution) is demonstrated with the moving platform. Two methods are proposed and partially demonstrated for pure translational motion: (1) integrated control system using a quad photo detector feedback and (2) corner cube retroreflector. The fundamental advantages and the limits of the lamellar grating interferometers are also discussed.

Disposable cartridge biosensor platform for portable diagnostics

We developed two types of cantilever-based biosensors for portable diagnostics applications. One sensor is based on MEMS cantilever chip mounted in a microfluidic channel and the other sensor is based on a movable optical fiber placed across a microfluidic channel. Both types of sensors were aimed at direct mechanical measurement of coagulation time in a disposable cartridge using plasma or whole blood samples. There are several similarities and also some important differences between the MEMS based and the optical fiber based solutions. The aim of this paper is to provide a comparison between the two solutions and the results. For both types of sensors, actuation of the cantilever or the moving fiber is achieved using an electro coil and the readout is optical. Since both the actuation and sensing are remote, no electrical connections are required for the cartridge. Therefore it is possible to build low cost disposable cartridges. The reader unit for the cartridge contains light sources, photodetectors, the electro coil, a heater, analog electronics, and a microprocessor. The reader unit has different optical interfaces for the cartridges that have MEMS cantilevers and moving fibers. MEMS based platform has better sensitivity but optomechanical alignment is a challenge and measurements with whole blood were not possible due to high scattering of light by the red blood cells. Fiber sensor based platform has relaxed optomechanical tolerances, ease of manufacturing, and it allows measurements in whole blood. Both sensors were tested using control plasma samples for activated-Partial-Thromboplastin-Time (aPTT) measurements. Control plasma test results matched with the manufacturer’s datasheet. Optical fiber based system was tested for aPTT tests with human whole blood samples and the proposed platform provided repeatable test results making the system method of choice for portable diagnostics.

Wearable and augmented reality displays using MEMS and SLMs

In this talk, we present the various types of 3D displays, head-mounted projection displays and wearable displays developed in our group using MEMS scanners, compact RGB laser light sources, and spatial light modulators.