高分子光电池研究进展

综述了高分子光电池的研究进展。对用作光电池的共轭高分子材料的发展作了跟踪报道。讨论了高分子异质结光电池的基本理论,对比了高分子光电池与无机半导体光电池载流子产生过程的差异,分析了高分子光电池效率和稳定性差的原因,指明了今后发展的方向。     

光电技术在纺织中的应用

从基于纺织品以及纤维的高性能光电池以及光电检测技术在大容量棉纤维长度检测中的应用两个方面出发,探讨光电技术在纺织中的应用。     

编码水准标尺检测的光电瞄准新方法

根据对编码水准标尺条纹图案的分布特征分析,并针对电子水准测量系统对标尺的精度要求,提出了一种多狭缝组合的光电显微镜瞄准检测标尺分划误差的方法。该方法中条纹图案由光学系统成像,并由前置多狭缝光阑的四象限光电池接收,光电池输出信号经处理后产生准确识别条纹中心的瞄准脉冲。该瞄准方法结合双频激光长度测量系统,可以实现编码标尺分划误差的动态检测,代替目前国内对编码水准标尺人工目视检测的过程。实验表明,该新型瞄准方法的瞄准精度优于2．0μm。     

自动套色系统中误差色标检测光电传感器的设计与实现

针对在凹版印刷中表征套印误差信息的色标信号检测问题.本文依据各颜色画面相对背景色对光能吸收不同的光学原理,利用半透半反光玻片的异面性和光电池光电转换功能,设计和实现了一种色标检测光电传感器.针对光电池光电转换输出信号较弱且非数字性的问题,进行了信号调理.实验结果和现场应用表明,该光电传感器具有结构简单.检测距离远((10±2)mm)、光斑半径小(φ1.5 mm)、灵敏度高、响应速度快(0.2 ms)、性能稳定可靠等优点.     

总光通量自动化检测

本文叙述了用球形光度计以比较法对白炽灯、荧光灯总光通量自动检测。该装置中以硅光电池代替硒光电池作光接收器,提高了测量稳定性和扩大了线性范围。     

基于硅光电池的照度测量设计

研究以硅光电池作为光感传感器,实现对光照度的测量。硅光电池输出弱电流信号通过调理、放大,接至单片机的A／D输入端,单片机对相应的电压信号进行采集和处理,通过线性化处理、工程量转换等方法,实现对100-5000Lx范围照度的测量。照度的精确检测除可以有效指导光度的调节外,还可针对密封环境中化学反应物发光强度来估计反应物的成分。     

揭穿硅光电池反向偏压的真面目及提高光还高频响应的最好办法

本文讨论了硅光电池所加反向偏压大小与信噪比的关系,并得出光电池偏压与信噪比存在反比关系的结论;并提出了提高光还高频响应的有效方法.     

揭穿硅光电池反向偏压的真面目及提高光还高频响应的最好办法

本文讨论了硅光电池所加反向偏压大小与信噪比的关系,并得出光电池偏压与信比存在反比关系的结论;并提出了提高光还高频响应的有效方法。     

基于硅光电池的色度测量系统设计

用光纤束传送经过变换的探测光脉冲序列,并投射到被测物体表面,或者传送到积分球再透射到被测物体表面.可获得四种色度测量几何条件;分别由置于积分球的三个作了光谱校正的硅光电池检测被物体待测表面反射的光信号,用精密调理电路将光电池输出的电流信号转换为可被单片机系统采集的电压信号;用z10近似表达x10的蓝色区域刺激值,通过软件校正三刺激值测量方程的有关因子.     

进口血氧分析器配用国产光电池

从美国、荷兰等国进口的各种型号的血氧分析仪器,常因光电池无法更新而使得整台仪器不能工作。这里介绍一种简单易行且又经济实用的解决办法,供大家参考。进口血氧分析仪器的光电池,其外形尺寸为45mm,与国产56A型光电池相同,虽然后者较厚,但尚能装下。据此我们在56A型上     

Near-infrared laser tomographic imaging with right-angled scattered coherent light using an optical heterodyne-detection-based confocal scanning system

We demonstrate, what is to the best of our knowledge, a novel optical tomographic method for the visualization of the inner structure of scattering media such as biological tissue in the near-infrared region. We constructed a scanning confocal imaging system with a cross-axes arrangement using optical fibers. This system is based on the optical heterodyne technique and enables the detection of very weak coherence photons that are generated in the spatially restricted confocal region and scattered laterally (90 degrees ) against an incident beam. To evaluate the fundamental imaging capabilities of the system, we assessed measurements from scattering phantoms composed of an Intralipid suspension with varying volume concentrations. The results of this study demonstrate that the right-angled scattered light adheres to the Lambert-Beer law and that the present system can detect light propagating through a distance of approximately 31l of the mean free path. An inclusion as small as 100 microm can be discriminated in a scattering media with an optical thickness of 4. We investigated the potential of the proposed system for imaging biological tissues in preliminary experiments using samples of chicken breast tissue.     

Single-scattering spectroscopy for the endoscopic analysis of particle size in superficial layers of turbid media

We report on the development of an optical-fiber-based diagnostic tool that is sensitive to single-scattering events close to the fiber-optic probe tip. By using a single fiber to deliver and detect white light we optimised the detection probability of singly scattered photons from small depths. The sampling depth of this delivery-and-collection fiber was investigated by use of a tissue phantom. We found that for our phantom 90% of the single-scattering signal in the delivery-and-collection fiber originated from less than 200 microm from the fiber tip. The contribution of multiply scattered light from a greater depth to the signal was measured with an additional collection fiber. Several tissue phantoms demonstrated our fiber-optic probes sensitivity to light scattering from superficial layers of tissue and thereby its potential to detect superficial precancerous epithelial lesions.     

Streak camera: a multidetector for diffuse optical tomography

We describe an experimental setup for time-resolved diffuse optical tomography that uses a seven-channel light guide to transmit scattered light to a streak camera. This setup permits the simultaneous measurement of the time profiles of photons reemitted at different boundary sites of the objects studied. The instrument, its main specifications, and detector-specific data analysis before image reconstruction are described. The instrumentation was tested with phantoms simulating biological tissue, and the absorption and reduced scattering images that were obtained are discussed.     

Effective phase function for light scattered by blood

The scattering process induced in blood by a collimated laser beam is theoretically investigated. An individual red blood cell (RBC) has a scattering phase function strongly peaked in the forward direction. For far-field experiments, the small scattering volumes can be considered as "macroscopic particles" characterized by an effective scattering phase function. Using the single-cell phase function as "input data" the angular distribution of light scattered at small angles by the whole scattering volume, containing RBCs in suspension, is calculated analytically. The angular dispersion of the light scattered by blood can be approximately described by the same formula used to characterize the light scattered by a single cell but with an effective, hematocrit-dependent anisotropy parameter.     

Spatial coherence of forward-scattered light in a turbid medium

We study spatially coherent forward-scattered light propagating in a turbid medium of moderate optical depth (0-9 mean free paths). Coherent detection was achieved by using a tilted heterodyne geometry, which desensitizes coherent detection of the attenuated incident light. We show that the degree of spatial coherence is significantly higher for light scattered only once in comparison with that for multiply scattered light and that it approaches a small constant value for large numbers of scattering events.     

偏振成像在目标探测中的应用

针对偏振度编码成像在目标探测识别中的优点,本文分析了偏振探测的消偏振机理,以及表面散射和体散射对目标偏振度的影响.利用808 nm半导体激光器照明,目标的后向散射光由卡塞格林望远镜接收,经过偏振分光棱镜成像在两个CCD上,通过一次测量获得偏振状态相互垂直的两幅图像,然后计算出目标的强度和偏振度,分别利用强度和偏振度编码成像.实验结果表明,在目标的反射率相近时,强度图像不能区分不同材料的目标,偏振度图像可以区分,融合强度和偏振度图像进行HSI伪彩色编码,可以达到目标探测、分类等目的.     

Tomographic image reconstruction from optical projections in light-diffusing media

The recent developments in light generation and detection techniques have opened new possibilities for optical medical imaging, tomography, and diagnosis at tissue penetration depths of ~10 cm. However, because light scattering and diffusion in biological tissue are rather strong, the reconstruction of object images from optical projections needs special attention. We describe a simple reconstruction method for diffuse optical imaging, based on a modified backprojection approach for medical tomography. Specifically, we have modified the standard backprojection method commonly used in x-ray tomographic imaging to include the effects of both the diffusion and the scattering of light and the associated nonlinearities in projection image formation. These modifications are based primarily on the deconvolution of the broadened image by a spatially variant point-spread function that is dependent on the scattering of light in tissue. The spatial dependence of the deconvolution and nonlinearity corrections for the curved propagating ray paths in heterogeneous tissue are handled semiempirically by coordinate transformations. We have applied this method to both theoretical and experimental projections taken by parallel- and fan-beam tomography geometries. The experimental objects were biomedical phantoms with multiple objects, including in vitro animal tissue. The overall results presented demonstrate that image-resolution improvements by nearly an order of magnitude can be obtained. We believe that the tomographic method presented here can provide a basis for rapid, real-time medical monitoring by the use of optical projections. It is expected that such optical tomography techniques can be combined with the optical tissue diagnosis methods based on spectroscopic molecular signatures to result in a versatile optical diagnosis and imaging technology.     

Blood-flow measurements with a small number of scattering events

Results of simulations of the diffraction of a laser beam by a small blood vessel imbedded in scattering tissue are presented. The form of the spectra of biospeckle intensity fluctuations is analyzed. The Doppler shift of intensity fluctuations of scattered light is investigated as a function of the laser beam radius, the radius of the blood vessel, the depth of the vessel in the tissue, and the scattering characteristics of flowing blood. A formula that serves as the basis for a method of absolute measurements of blood-flow velocity is derived.     

Multiple-scattering suppression in dynamic light scattering based on a digital camera detection scheme

We introduce a charge-coupled device (CCD) camera-based detection scheme in dynamic light scattering that provides information on the single-scattered autocorrelation function even for fairly turbid samples. It is based on the single focused laser beam geometry combined with the selective cross-correlation analysis of the scattered light intensity. Using a CCD camera as a multispeckle detector, we show how spatial correlations in the intensity pattern can be linked to single- and multiple-scattering processes. Multiple-scattering suppression is then achieved by an efficient cross-correlation algorithm working in real time with a temporal resolution down to 0.02 s. Our approach allows access to the extensive range of systems that show low-order scattering by selective detection of the singly scattered light. Model experiments on slowly relaxing suspensions of titanium dioxide in glycerol were carried out to establish the validity range of our approach. Successful application of the method is demonstrated up to a scattering coefficient of more than micro(S) = 5 cm(-1) for the sample size of L = 1 cm.