320×240长波非致冷微测辐射热计红外热象仪的研制

介绍了基于微测辐射热计320×240长波非致冷红外热象仪的研制,详细说明了其电气系统的设计方法及技术关键,并对其光学系统进行了简要说明.采用高象质的双反射光学系统以减少象差;红外探测器采用320×240长波非致冷集成微测辐射热计红外焦平面阵列(FPA);电气系统采用复杂可编程逻辑器件(CPLD)完成红外焦平面阵列的驱动,应用数字信号处理(DSP)技术实现红外焦平面阵列的非均匀性校正、图象增强及红外图象实时显示等.     

High-performance modulation-doped AlGaAs/InGaAs thermopiles for uncooled infrared FPA application

Novel thermopile based on modulation doped AlGaAs/InGaAs heterostructures is proposed and developed for the first time, for uncooled infrared FPA (Focal Plane Array) image sensor application. The high responsivity with the high speed response time are designed to be 4900 V/W with 110 μs under the 2 μm design rule. Based on integrated HEMT–MEMS technology, the 32 × 32 matrix FPA is fabricated to demonstrate its enhanced performances by black body measurement. The technology presented here demonstrates the potential of this approach for low-cost uncooled infrared FPA image sensor application.     

Novel uncooled infrared detectors

Despite successful commercialization of uncooled microbolometers suitable for imaging, the community is still searching for a platform for imagers that combine affordability, convenience of operation, and excellent performance. More recently, a new type of uncooled detectors based on expansion phenomena in micromechanical structures has been introduced. These detectors are essentially free of intrinsic electronic noise and can be combined with a number of different readout techniques including: capacitive, piezoresistive, electron tunnelling, and optical. In this paper, their design structures and performance are discussed in more detail.     

利用电子俘获材料研制复合型短波红外探测器

论述了短波红外探测技术的发展状况及其在探测、识别和遥感等领域的需求。阐述了高分辨、低成本的短波红外探测器的研究意义。分析了电子俘获材料(ETM)的上转换功能及其光学特性,提出了ETM与CCD结合实现复合短波红外探测的方案,并获得了初步的实验结果。     

Polycrystalline lead selenide: the resurgence of an old infrared detector

The existing technology for uncooled MWIR photon detectors based on polycrystalline lead salts is stigmatized for being a 50-year-old technology. It has been traditionally relegated to single-element detectors and relatively small linear arrays due to the limitations imposed by its standard manufacture process based on a chemical bath deposition technique (CBD) developed more than 40 years ago. Recently, an innovative method for processing detectors, based on a vapour phase deposition (VPD) technique, has allowed manufacturing the first 2D array of polycrystalline PbSe with good electro optical characteristics. The new method of processing PbSe is an all silicon technology and it is compatible with standard CMOS circuitry. In addition to its affordability, VPD PbSe constitutes a perfect candidate to fill the existing gap in the photonic and uncooled IR imaging detectors sensitive to the MWIR photons. The perspectives opened are numerous and very important, converting the old PbSe detector in a serious alternative to others uncooled technologies in the low cost IR detection market. The number of potential applications is huge, some of them with high commercial impact such as personal IR imagers, enhanced vision systems for automotive applications and other not less important in the security/defence domain such as sensors for active protection systems (APS) or low cost seekers. Despite the fact, unanimously accepted, that uncooled will dominate the majority of the future IR detection applications, today, thermal detectors are the unique plausible alternative. There is plenty of room for photonic uncooled and complementary alternatives are needed. This work allocates polycrystalline PbSe in the current panorama of the uncooled IR detectors, underlining its potentiality in two areas of interest, i.e., very low cost imaging IR detectors and MWIR fast uncooled detectors for security and defence applications. The new method of processing again converts PbSe into an emerging technology.     

Infrared Optical Fiber Sensors

Notably improved performance as well as extended application areas is expected in the technology of optical fiber sensors using infrared fibers that transmit radiation in a wavelength range beyond 2 μm. Measurement of infrared radiation is particularly important in thermometry and spectrometry. In these areas, the use of infrared fibers has been studied extensively not only as a transmission waveguide but also as a sensor chip. Of various infrared fibers, fluoride glass fibers exhibit the lowest transmission loss and hence are useful for remote sensing that requires light transmission over a long distance. The wide transmission range of chalcogenide glass fibers and halide crystalline fibers is valuable for thermometry in a low temperature range and for spectrometry of various molecules. Hollow waveguides are useful as a capillary flow cell that realizes fast-response spectrometry. The advantages and disadvantages of infrared fibers must be considered carefully in the development of fiber sensors. In this paper, the progress of infrared optical fiber sensors is reviewed with particular interest in thermometry and spectroscopy.     

The influence of hard-baking temperature applied for SU8 sensor layer on the sensitivity of capacitive chemical sensor

SU8, the near-UV photosensitive epoxy-based polymer was used as a sensor layer in the capacitive chemical sensor, ready for integration with a generic double-metal CMOS technology. It was observed that the response of the sensor slowly increases with the temperature applied in hard-baking process as long as it remains below 300°C. At this temperature the response of the sensor abruptly increases and becomes almost threefold. It was shown that fully crosslinked structure of the sensor layer becomes opened and disordered when the sensor is hard-baked at temperatures between 300°C and 320°C, that is, still well below the degradation temperature of the polymer. These changes in chemical structure were analyzed by Fourier-transform infrared spectroscopy. The temperature-dependent changes of the sensor layer structure enable one to prepare a combination of capacitive chemical sensors with good discrimination between some volatile organic compounds.     

光学读出非制冷红外成像技术的光学灵敏度分析

不同于传统的非制冷红外成像技术,提出了基于微电子机械系统(MEMS)的新概念光学读出非制冷红外成像技术。它的光学读出系统基于空间刀口滤波原理,具有高灵敏度、高分辨率和高抗震性等优点,但同时也受到了反光板的弯曲变形、粗糙度等复杂因素的影响。在大量实验数据的基础上,利用夫琅禾费近场衍射理论,建立了复杂因素下光学灵敏度的理论分析模型,详细分析了刀口滤波位置、反光板的长度、曲率半径、粗糙度、LED光源的强度以及扩展宽度等对光学灵敏度的影响,并提出了通过极限操作使系统的光学灵敏度最大化的光学优化方法。     

非制冷红外探测器读出电路的非均匀性研究

对于长线列的非制冷红外探测器组件, 不同探测元之间的非均匀性是衡量电路设计的关键指标. 为了实现长线列非制冷红外探测器的高性能读出, 本文设计了一种基于电流镜方式的非制冷红外探测器160线列读出电路, 电路由电流镜输入模块、电容负反馈互导放大器模块及相关双采样输出模块组成. 电路采用0.5 μm工艺制作完成. 通过合理设置电路中MOS管的参数和布局电流镜版图, 电路的非均匀性有了明显地改善. 通过测试, 电路的非均匀性小于1%, 器件总功耗约为100 mW, 并具有良好的低噪声特性, 输出噪声小于1 mV, 输出摆幅大于2 V. 该电路与160线列非制冷红外探测器互连后, 能较好地完成红外信号的读出, 在积分时间为20 μups的情况下, 器件的响应为0.294 mV/Ω, 整体性能良好. 该电路的研制对超长线列的非制冷红外冷探测器读出电路研制奠定了重要的技术基础.     

凝视型非制冷红外热像仪的优化设计

概述了凝视型非制冷热像仪作用距离估算的几种模型及其特点.采用NVTherm分析了320×240凝视型非制冷热像仪的调制传递函数、最小可分辨温差和探测距离.分析结果表小F/#、减小像元间距都能够改善凝视型非制冷热像仪的性能,增加作用距离.外场试验结果与NVTherm的仿真值符合得比较好,表明可以利用NVTherm对凝视型非制冷红外热像仪的设计过程进行优化,并能缩短设计周期.     

血液的红外吸收光谱分析及应用研究

开展红外光谱法的应用研究，对促进光测技术发展有重要作用。本文针对血液的红外光谱分析这一重要课题，提出了血液的红外吸收光谱分析新技术，通过对正常与异常血液的红外吸收光谱进行测量，分析并比较不同血液红外吸收光谱之间的差异，即可判断血样是否正常，其实验具有一定的先进性。文中分析了正常血样和异常血样的红外吸收光谱之间的差别，并给出了人的正常全血和血清与高糖全血的红外吸收光谱及分析结果，为进一步用于疾病诊断提供了实验依据。其研究结果对血液红外光谱分析并用于疾病诊断有重要价值。本文的研究为红外吸收光谱的测量及应用开辟了新的途径。     

Low-Temperature Radiometric Measurements Using a Silver Halide Optical Fiber and Infrared Optical Devices

In this study, we measured an infrared radiation which is transferred by a silver halide optical fiber from a heat source using a radiometer system for low-temperature measurements. To increase the amount of infrared radiation through the silver halide optical fiber and to the pyroelectric sensor, infrared optical devices used were an infrared focusing lens and a collimator. The relationship between the temperatures of a heat source and the measured radiometer signals were determined. The measurable temperature range of a fiber-optic temperature sensor using a pyroelectric sensor was from 298 to 333 K. It is expected that a noncontact low-temperature sensor using an infrared optical fiber can be developed for medical and industrial usages based on the results of this study.     

Thermal Behavior of Amorphous Silicon Thin Film Transistor and Its Application to Micromachined Uncooled Infrared Sensors

This work reports a new uncooled infrared sensor based on amorphous silicon thin film transistors (a-Si TFTs). The temperature coefficient of channel current (TCC) of the a-Si TFT is given. Analysis shows that the a-Si TFT working in the saturation region is preferred for the sensitive element with a TCC value of 3.8-6.0 %/K. The a-Si TFT is placed on a suspended microbridge to reduce the thermal conductance by using micro-electro-mechanical system (MEMS) technology. The a-Si TFT-based IR sensor with a monolithic architecture is fabricated. Preliminary experimental results show that a responsivity of 40.8 kV/W, a thermal response time of 5.5 ms and a NETD of 90 mK are achieved.     

QWIP or other alternative for third generation infrared systems

Choosing the right detector technology for third generation thermal imaging systems is directly derived from the requirements of these new generation infrared imaging systems.

It is now evident that third generation thermal imager will still need the higher resolution capabilities as well as capabilities in multispectral detection and polarization sensitivity. Four technologies candidates are analyzed; the field-proved HgCdTe (MCT), uncooled microbolometer technology, antimonide based materials and quantum well infrared photodetectors (QWIP). Taking into account the risks, maturity and technologies barrier of each technology, we claim that for non-strategic applications (not low background conditions), QWIP technology is the most favorite. The ternary and superlattice antimonide based materials group seems to be theoretically the best alternative, but are not recommended due to its immaturity and the high risk involved in this technology (passivation, doping control, etc.). We anticipate large penetration of the uncooled detectors to the low-end and medium-end market. The HgCdTe will still be in progress due to the inertia of the large funding and the strategic importance of this detectors technology.     

Uncooled microbolometer detector: recent developments at ULIS

Uncooled infrared focal plane arrays are being developed for a wide range of thermal imaging applications. Fire-fighting, predictive maintenance, process control and thermography are a few of the industrial applications which could take benefit from uncooled infrared detector. Therefore, to answer these markets, a 35-μm pixel-pitch uncooled IR detector technology has been developed enabling high performance 160×120 and 384×288 arrays production. Besides a wide-band version from uncooled 320×240/45 μm array has been also developed in order to address process control and more precisely industrial furnaces control. The ULIS amorphous silicon technology is well adapted to manufacture low cost detector in mass production. After some brief microbolometer technological background, we present the characterization of 35 μm pixel-pitch detector as well as the wide-band 320×240 infrared focal plane arrays with a pixel pitch of 45 μm. The paper presented there appears in Infrared Photoelectronics, edited by Antoni Rogalski, Eustace L. Dereniak, Fiodor F. Sizov, Proc. SPIE Vol. 5957, 59570M (2005).     

Infrared radiation thermometer using a silver halide optical fiber for thermal ablation

In this study, we have fabricated non-contact temperature sensor using an infrared optical fiber for measuring temperature distributions during radiofrequency ablation. We have measured an infrared radiation, which is transferred by a silver halide optical fiber from the multi-points on the water around inserted electrode, using a thermopile sensor and the output voltages of a thermopile sensor are compared with those of the thermocouple recorder. Also, the relationship between the temperatures and the output voltages of a thermopile sensor at the measuring points is determined to obtain the temperature distribution. The measurable temperature range of a fiber-optic non-contact temperature sensor is from 37 to 80 °C.     

光成像技术用于地铁电阻式制动器热变形的测量

由于瞬间负载大电流产生电热冲击,使得地铁使用的制动电阻器内部电阻片在热力耦合作用下过度变形。为消除接触式传感器本身对温度场和位移场的干扰,对温度和变形均采用了非接触式测量。在温度的测量中,采用了红外线遥感测温仪;在变形的测量中,应用了以数字光栅投影和Gray-code编码法为基础的结构光三维成像技术,对13个不同温度点进行了电阻片的热变形测量。通过系统标定和误差控制,使得变形测量系统的误差在0.1mm以内。非接触式测量是热应力实验研究的发展方向,而光学成像技术在热变形检测中的应用,为热应力的实验研究开辟了新的途径。     

Simulation method for LWIR radiation distribution using a visual ray-tracer

Optical and Quantum Electronics - Infrared cameras with passive, uncooled sensor chips utilize the longwave infrared (LWIR) range of the electromagnetic spectrum with wavelengths between 8 and...     

电容式微超声波换能器的设计与电容值测试*

本文设计的微电容超声波换能器(CMUT)是由电容阵列组成的超声波传感器,主要是利用电容的改变来实现能量的转换。是基于硅硅键合技术的MEMS电容式超声传感器,制作的传感器误差小,并且工艺流程简单且能进行量产。在利用E4990A阻抗分析仪对传感器进行C—V测试分析而得出其电容的实际值与理论值的误差仅为1.6%。并且利用该仪器测试传感器电容在工作电压下随频率的变化,得出其在工作电压下,频率为400K的时候电容值为617.67PF,为对传感器进行理论计算提供了重要支撑,并且为后续转换电路的设计提供了数据支撑。     

一种折反式红外/激光复合导引头光学系统设计

设计了一种用于长波非制冷红外和半主动激光复合导引的共口径折反式光学系统。为了减小反射式系统的零件加工和装调难度,将卡塞格林系统次反射镜简化为平面反射镜,主反射镜采用金属抛物面,优化目镜组透镜尺寸,避免光路内部遮挡,利用反射式系统一次像面,配合红外材料选取实现红外通道的光学被动消热差设计;在平行光路中设置平板分光和激光窄带滤光片,提高系统分光效率和透过率。设计结果表明:红外通道特征频率35.7 lp/mm处MTF＞0.2,激光线性区为2°,满足系统指标要求。