Herein, a finger-free wrist-worn pulse oximeter is presented. This device allows patients to measure blood oxygen level and pulse rate without hindering their normal finger movement. This wrist-worn pulse oximeter is built with a reflectance oximetry sensor, which consists of light emitting diodes and photodiode light detectors located side by side. This reflectance oximetry sensor is covered with an optical element with micro structured surface. This micro structured optical element is designed to modulate photon propagation beneath the skin tissue so that the photoplethysmogram signals of reflected lights or backscattered lights detected by the photodetector are therefore enhanced.
Due to Light Emitting Diode (LED) have the properties of compact size and high efficiency, there have more and more illumination system use it to be a lighting source. In this paper, a compact projection system was designed by a simple architecture. For this compact projection system, the prototype has been developed by using a single tranmissive light valve and LED source in it. With a simple collecting light reflector, a curved mirror and a light tunnel of the illumination system, the optical efficiency from the source to light valve is up to over 70% and the uniformity illuminated on the light valve is over 85%.
All-optical modules are devices which process and transport optical signals without transforming to electronic signals. They get more attention as the optical communication network becomes more and more complicated. Among them, OADM (optical add drop module) is one of the most important devices in the optical DWDM (dense wavelength division multiplex) network. It plays the role of a node in network to upload/download signals or to route signals for optical performance monitoring. Applied broadly in projection display systems, DLP (Digital Light Processing) from Texas Instruments turns out to be a versatile device for optical signal processing. The working principle of DLP is based on so called switched-blazed-grating. Part of its micro-mirror array can be formed as a dynamic blazed grating with a period of 14 μm by tilting the micro-mirrors at an angle of ±12 degrees. It is expected to function as either a switch or an attenuator by directing total or part of the incident light between the 2nd and -2nd diffraction orders. In this paper, we investigate the optical characteristics of a switched-blazed-grating, its application as a re-configurable OADM, and the performance of such a device. Ray tracing and optical analysis of the OADM are made by using package software ASAP from Breault Research Organization. In conclusion, as a mature and reliable MEMS device, DLP-based switched-blazed-grating provides a very versatile platform for digital optical signal processing and can be used as a dynamic optical-networking device with good performance.
There are many reasons that can degrade the image quality performance in a projection system, such as environment temperature, MTF of projection lens, structure of Lcd panel, EMI on the PCB and driver scheme... etc. Image quality is a function of all these parameters. In this article, the authors would like to estimate the image quality of a projection system under driver schemes and design parameters from the system point of view. The relationships between the voltage difference applied on liquid crystal (LC) cell and defect phenomenon are also revealed. This gives a clear-cut for different image defect (ex: flicker) and its causality. In the present time, ITRI/OES were modeling the LCOS Panel pixel with SpiceTM and ASAPTM for the estimation of image quality during the design of the optical engine.