Optical format

Abstract: An infrared line-scanning imager includes a scanner having an optical system, infrared linear photoconductive detector providing an analog image signal, cooler, and conversion electronics for converting the image signal from the detector to digital electrical and digitally-encoded optical formats, all on a moving scanning platform of the scanner. The digitally-encoded optical format of the image signal takes the form of an encoded light beam which is beamed off of the moving scanning platform to a receiver on the stationary portion of the scanner. From the scanner, the image signal is transmitted in the optical format over a fiber optic cable to a reformatting, processing, analysis, and display portion of the imager. This latter portion of the imager allows the image signal to be converted once again to digital electronic format for processing, pattern recognition, image enhancement, storage, delayed display and comparison, and display in near-real time if desired.

Abstract: A bipolar imager with an amplification function in each pixel has been developed using BiCMOS technology. The imager, which stores photocarriers in the base regions of the bipolar transistor pixels, is called the base-stored image sensor (BASIS). BASIS-type devices have been faced with three problems: (1) a reset transistor is needed in each pixel to initialize base voltage; (2) nonuniformity of offset voltage appears as fixed pattern noise; and (3) blooming is induced by intense light. Effective methods of dealing with these problems have been found. A BASIS imager with 310 k pixels in a 2/3-in optical format is described. The device specifications and characteristics of the imager are summarized. >

Abstract: 1. Abstract Intevac has developed a new Low Light Level Camera sensor technology for application to a variety of low light level imaging applications. The new sensor is an Electron Bombarded Active Pixel Sensor (EBAPS). EBAPS technology is based on use of a GaAs photocathode derived from Generation-III image intensifier technology in proximity focus with a high resolution, backside thinned, CMOS Active Pixel Sensor (APS) imager anode. The electrons emitted by the photocathode are directly injected in the electron bombarded mode into the CMOS APS anode. In this approach low noise gain is achieved in the CMOS anode via conversion of the high energy photoelectron (1 - 2 KeV resulting from the high voltage bias applied between the photocathode and CMOS anode) to electron-hole pairs in the anode via the Electron Bombarded Semiconductor (EBS) gain process. The electrons are collected in the APS pixel and subsequently read out. The EBS gain process is inherently low noise with an excess noise factor (Kf) of less than 1.1. This is substantially less than a microchannel plate based Generation-III image intensifier (MCP, Kf of 1.8) or the avalanche gain process in an Electron Multiplying CCD (EMCCD, Kf of 1.4). The low noise EBS gain process eliminates the need for an MCP and enables higher SNR at the lowest light levels. This offers the possibility of higher performance for an EBAPS based camera relative to a standard Image Intensified camera based on Gen-III tube technology using an MCP for gain or EMCCD based cameras. This low noise gain advantage has been combined with modern semiconductor packaging and manufacturing approaches to enable a small integrated EBAPS module which can be mass produced at low cost in an automated ultra high vacuum production packaging system. This new sensor manufacturing approach allows high volume, cost sensitive, markets to be addressed. It also enables a variety of sensor formats to be easily addressed as it allows combination of standard CMOS APS imaging chips with a GaAs photocathode in the EBAPS configuration. This allows customization of the EBAPS for a given camera application. EBAPS technology will be described with its application in a first generation EBAPS sensor and low light level camera (NightVista) developed for commercial security camera applications. The NightVista camera has a 1/2 inch optical format and a VGA (640 x 480) array with a 12µm pixel. The camera incorporates a gated high voltage power supply for automatic gain control. It also incorporates 2 point non-uniformity correction (NUC), bad pixel replacement, and histogram equalization image processing functions. The EBAPS sensor, high voltage power supply and camera electronics combined weight is 45 grams (not including camera housing). This is approximately 60% of the weight of a Generation-III image intensifier module as used in a standard night vision goggle. The EBAPS sensor and electronics are also ideally suited to head mounted system packaging and enable system designs with minimum forward projection relative to currently fielded night vision goggles. Results will also be presented for a next generation EBAPS camera based on the ISIE6 (Intevac Silicon Imaging Engine), SXGA (1280 x 1024 array, 6.7 µm pixel), EBAPS sensor with a 2/3 inch optical format. The ISIE6 EBAPS has lower readout noise than the NightVista EBAPS sensor for improved low light level performance and supports a 27.5 fps readout rate. Finally performance modeling will presented on a larger 1 inch optical format, SXGA, ISIE10 EBAPS sensor under development for an EBAPS camera targeted for future high performance head mounted night vision applications.

Abstract: A disposable optical format for lancing the skin of a patient and harvesting blood to determine blood chemistries such as glucose level includes a housing with openings defining an optical path. A translucent hollow capillary tube with multiple planar sides and an end cleaved to a sharp edge is mounted in the housing. The sides of the tube are formed of an optical material such as fused silica. Significantly less pain, high probability of blood harvesting and improved overall test time are achieved with integrating the lance, harvest and analysis operation.