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公开(公告)号：US5864399A
公开(公告)日：1999-01-26
申请号：US879665
申请日：1997-06-23
CPC分类号： G01N15/1434 , G01N15/1404 , G01N2021/391
摘要： A particle detector employs a laser having a solid-state lasing medium, such as an Nd:YAG crystal, disposed in a resonant cavity, and includes an intracavity view volume. The resonant cavity is defined by two spaced apart mirrors, with the laser medium positioned between them, defining a light path. A pump source is optically coupled to drive the laser medium to produce coherent light having a first wavelength. The view volume is positioned in the light path, between the first mirror and the laser medium, to introduce particles into the resonant cavity so that light impinging there-upon produces scattered light. A detector is disposed to sense light scattered from the view volume and produces signals proportional to the light sensed. A displaying device, such as a pulse height analyzer, is in electrical communication to receive the signals produced by the detector to quantitatively display the intensity of the light sensed. In an alternate embodiment, a harmonic generator is disposed within the light path to shorten the wavelength of light impinging upon particles in the view volume, making the detector more sensitive to particles of sub-micron size.
摘要翻译： 粒子检测器使用具有设置在谐振腔中的固态激光介质（例如Nd：YAG晶体）的激光器，并且包括腔内视图体积。 谐振腔由两个间隔开的反射镜限定，其中激光介质位于它们之间，限定光路。 光源耦合以驱动激光介质以产生具有第一波长的相干光。 视图体积位于第一反射镜和激光介质之间的光路中，以将颗粒引入谐振腔中，使得在其上入射的光产生散射光。 设置检测器以感测从视野体积散射的光并产生与所感测光成比例的信号。 诸如脉冲高度分析仪之类的显示装置通电，以接收由检测器产生的信号，以定量显示感测光的强度。 在替代实施例中，谐波发生器设置在光路内以缩短照射在视野体积中的颗粒上的光的波长，使得检测器对亚微米尺寸的颗粒更敏感。
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公开(公告)号：US6137572A
公开(公告)日：2000-10-24
申请号：US183582
申请日：1998-10-30
CPC分类号： G01N15/0205 , G01N15/0211 , G01N2021/391
摘要： An optical scattering particle counter uses optical scattering and heterodyne detection techniques to overcome the lower limit on particle size detection stemming from background light scattering by the fluid carrier in which a particle is immersed. The particle counter uses a heterodyne technique to exploit a basic physical difference between target particle scattered light and the background light. For gas-borne particulate monitoring, the carrier gas molecules have a pronounced temperature-induced Maxwell-Boltzmann translational velocity distribution and an associated Doppler broadened spectral scattering characteristic that are dissimilar to those of the target particle. The Doppler broadened background Rayleigh light is orders of magnitude spectrally wider than that scattered by a particle in a particle detector view volume. This difference in bandwidth allows the local oscillator light to "tune in" the target particle light in a beat frequency signal and "tune out" the background radiation. In this way, most of the Rayleigh scattered light signal can be removed from the total signal, leaving a dominant target particle signal. For liquid-borne particulate monitoring, background optical noise generated by Brillouin scattering by the liquid carrier places a lower limit on particle size detection. With heterodyne detection techniques, the Brillouin broadening of the background light signal significantly reduces the background light signal seen by the photodetector. For gas-borne or liquid-borne particulate monitoring, the heterodyne beat frequency signal not only reduces the background light signal but also increases the signal representing the target particle light. With heterodyne detection, the beat frequency signal is proportional to the square root of the product of the target particle signal optical power and local oscillator beam optical power. Because the local oscillator beam optical power can be many orders of magnitude greater than the target particle signal optical power, the beat frequency signal can be many orders of magnitude larger for coherent (i.e., heterodyne) detection than the scattered light signal for direct optical detection.
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3.发明授权Dual detector array with noise cancellation for a particle size detection device 失效用于粒度检测装置的具有噪声消除的双检测器阵列
公开(公告)号：US6061132A
公开(公告)日：2000-05-09
申请号：US119379
申请日：1998-07-20
CPC分类号： G01N15/0211
摘要： In a particle detector, a stream carrying particles to be measured is passed through a laser beam. A pair of optical collection systems are arranged perpendicular to the laser beam, opposing each other. The optical collection system reflects light signals indicative of particles sensed in the sensing region to a pair of detector arrays. Each detector array has a plurality of detectors to detect the particle signals, as well as other noise. One detector from each array monitors the same sensing region. The signals from the detectors are processed through a noise cancellation circuit. The noise cancellation circuit first amplifies each detector signal through a photo-amp. Then, the signals of the detectors in one detector array are paired up with corresponding signals of detectors, spaced at least two detectors away, in the other detector array. The paired-up signals pass through differential amplifiers, which essentially cancel the light fluctuation noise. The remaining particle signals are further processed through an A/D converter to a user interface. The dual detector array is able to achieve a better than 0.10 micron sensitivity at a particle flow of 1.0 cubic foot per minute.
摘要翻译： 在颗粒检测器中，携带待测颗粒的流通过激光束。 一对光学收集系统垂直于激光束布置，彼此相对。 光学收集系统将表示在感测区域中感测的颗粒的光信号反映到一对检测器阵列。 每个检测器阵列具有多个检测器以检测粒子信号以及其它噪声。 来自每个阵列的一个检测器监测相同的感测区域。 来自检测器的信号通过噪声消除电路进行处理。 噪声消除电路首先通过光电放大器放大每个检测器信号。 然后，在另一个检测器阵列中，一个检测器阵列中的检测器的信号与检测器的相应信号配对，间隔开至少两个检测器。 配对信号通过差分放大器，其基本上消除了光波动噪声。 剩余的粒子信号通过A / D转换器进一步处理到用户界面。 双检测器阵列能够在每分钟1.0立方英尺的粒子流量下实现优于0.10微米的灵敏度。
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公开(公告)号：US5946092A
公开(公告)日：1999-08-31
申请号：US200206
申请日：1998-11-25
CPC分类号： G01N15/0205 , G01N15/0211 , G01N2021/391
摘要： A gas-borne optical scattering particle counter uses intracavity optical scattering and heterodyne detection techniques to overcome the lower limit on particle size detection stemming from background light scattering by the gaseous carrier in which a particle is immersed. The particle counter uses a heterodyne technique to exploit a basic physical difference between target particle scattered light and the background light. The carrier gas molecules have a pronounced temperature-induced Maxwell-Boltzmann translational velocity distribution and an associated Doppler broadened spectral scattering characteristic that are dissimilar to those of the target particle. The Doppler broadened background Rayleigh light is orders of magnitude spectrally wider than that scattered by a particle in a particle detector view volume. This difference in bandwidth allows the local oscillator light to "tune in" the target particle light in a beat frequency signal and "tune out" the background radiation. In this way, most of the Rayleigh scattered light signal can be removed from the total signal, leaving a dominant target particle signal. To develop sufficient local oscillator power, an embodiment using intracavity optical scattering and heterodyne detection techniques is implemented in a dual laser configuration in which a first laser serves for intracavity light scattering and a second laser functions as the local oscillator. The first and second lasers are frequency locked to maintain a substantially constant frequency difference between them and thereby obtain a stable beat frequency signal. The beat frequency signal is proportional to the square root of the product of the target particle signal optical power and the local oscillator power and can be many orders of magnitude larger for coherent (i.e., heterodyne) detection than the scattered light signal for direct optical detection.
摘要翻译： 气体光散射粒子计数器使用腔内光散射和外差检测技术来克服由其中沉积颗粒的气态载体的背景光散射引起的粒度检测的下限。 粒子计数器使用外差技术来利用目标粒子散射光与背景光之间的基本物理差异。 载气分子具有显着的温度诱导的麦克斯韦 - 玻尔兹曼平移速度分布和与目标颗粒不同的多普勒扩展光谱散射特征。 多普勒扩展的背景瑞利光比粒子检测器视图体积中的粒子散射的数量级更多。 带宽差异允许本地振荡器光“拍摄”拍频信号中的目标粒子光并“调出”背景辐射。 以这种方式，可以从总信号中去除大部分瑞利散射光信号，留下主要的目标粒子信号。 为了开发足够的本地振荡器功率，使用腔内光散射和外差检测技术的实施例以双激光器配置实现，其中第一激光器用于腔内光散射，第二激光器用作本地振荡器。 第一和第二激光器被锁频以保持它们之间基本上恒定的频率差，从而获得稳定的拍频信号。 拍频信号与目标粒子信号光功率和本地振荡器功率的乘积的平方根成比例，并且与用于直接光学检测的散射光信号相比（即外差）检测可以更多数量级 。
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5.发明授权Particle counter employing a solid-state laser with an intracavity view volume 失效使用具有腔内视图体积的固态激光器的粒子计数器
公开(公告)号：US5642193A
公开(公告)日：1997-06-24
申请号：US614814
申请日：1996-03-08
CPC分类号： G01N15/1434 , G01N15/1404 , G01N2021/391
摘要： A particle detector employs a laser having a solid-state lasing medium, such as an Nd:YAG crystal, disposed in a resonant cavity, and includes an intracavity view volume. The resonant cavity is defined by two spaced apart mirrors, with the laser medium positioned between them, defining a light path. A pump source is optically coupled to drive the laser medium to produce coherent light having a first wavelength. The view volume is positioned in the light path, between the first mirror and the laser medium, to introduce particles into the resonant cavity so that light impinging thereupon produces scattered light. A detector is disposed to sense light scattered from the view volume and produces signals proportional to the light sensed. A displaying device, such as a pulse height analyzer, is in electrical communication to receive the signals produced by the detector to quantitatively display the intensity of the light sensed. In an alternate embodiment, a harmonic generator is disposed within the light path to shorten the wavelength of light impinging upon particles in the view volume, making the detector more sensitive to particles of sub-micron size.
摘要翻译： 粒子检测器使用具有设置在谐振腔中的固态激光介质（例如Nd：YAG晶体）的激光器，并且包括腔内视图体积。 谐振腔由两个间隔开的反射镜限定，其中激光介质位于它们之间，限定光路。 光源耦合以驱动激光介质以产生具有第一波长的相干光。 视图体积位于第一反射镜和激光介质之间的光路中，以将颗粒引入谐振腔中，使得入射到其上的光产生散射光。 设置检测器以感测从视野体积散射的光并产生与所感测光成比例的信号。 诸如脉冲高度分析仪之类的显示装置通电，以接收由检测器产生的信号，以定量显示感测光的强度。 在替代实施例中，谐波发生器设置在光路内以缩短照射在视野体积中的颗粒上的光的波长，使得检测器对亚微米尺寸的颗粒更敏感。
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公开(公告)号：US07355706B2
公开(公告)日：2008-04-08
申请号：US11241216
申请日：2005-09-30
CPC分类号： G01N15/1459 , G01N21/94 , G01N2015/1493
摘要： Fluid-based particle detection exhibits improved light collection and image quality from a light collection system that uses immersed optics on a flow-through cell for collecting and detecting scattered light from particles carried by the fluid. The flow-through cell includes first and second body sections that are coupled to form a unitary article and have opposed interior surface portions configured to form opposed walls of a flow channel through which the fluid flows. First and second optical elements are associated with the respective first and second body sections. In certain embodiments, at least one of the first and second optical elements is an integral part of its associated body section. A lens element constructed as an integral part of the unitary flow-through cell eliminates additional interfaces or bonding joints that cause scattering and absorption of light.
摘要翻译： 基于流体的颗粒检测表现出来自采集系统的光采集和图像质量的改善，该采集系统使用浸入式光学器件用于流通池，用于收集和检测由流体携带的颗粒散射的光。 流通池包括第一和第二主体部分，其连接以形成整体制品并且具有相对的内表面部分，该内表面部分被构造成形成流体流过的流动通道的相对的壁。 第一和第二光学元件与相应的第一和第二主体部分相关联。 在某些实施例中，第一和第二光学元件中的至少一个是其相关联的主体部分的整体部分。 构成整体流通池的整体部分的透镜元件消除了引起光的散射和吸收的附加接口或接合接头。
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公开(公告)号：US06784990B1
公开(公告)日：2004-08-31
申请号：US10407650
申请日：2003-04-04
IPC分类号： G01N2100
CPC分类号： G01N21/53 , G01N15/1429 , G01N15/1459 , G01N2015/1402
摘要： A particle detection system exhibits an increased ability to detect the presence of submicron diameter particles and to distinguish between noise and pulse output signals generated by small diameter particles on which a light beam is incident. This increased ability results from the incorporation of a light reflector, a pair of detector elements that detect correlated portions of the light beam that have been scattered in multiple directions, and a coincidence circuit that determines whether each detector element in the pair concurrently generates a pulse output signal exceeding a predetermined threshold. Sample particles are counted only when both detector elements concurrently detect scattered light components.
摘要翻译： 颗粒检测系统表现出增加的检测亚微米直径颗粒的存在的能力，并且区分由光束入射的小直径颗粒产生的噪声和脉冲输出信号。 这种增加的能力来自于结合光反射器，检测已经在多个方向上散射的光束的相关部分的一对检测器元件，以及确定该对中的每个检测器元件是否同时产生脉冲的符合电路 输出信号超过预定阈值。 只有当两个检测器元件同时检测散射光分量时，才对样品颗粒进行计数。
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公开(公告)号：US6111642A
公开(公告)日：2000-08-29
申请号：US160557
申请日：1998-09-24
CPC分类号： G01N15/0211 , G01N2021/391
摘要： A particle counter (10) passes a sample stream of a carrier gas or fluid containing particles (72) through an elongated, flattened nozzle (16) and into a view volume (18) formed by an intersection of the sample stream and a laser beam (13). Particles entrained in the sample stream scatter light rays while passing through the view volume. The scattered light is collected by an optical system (26) and focused on to a detector (40). The magnitude of signal coming from the detector is indicative of the particle size. To correct for variances in particle velocity and light beam intensity across the view volume, flow aperturing is used. Flow aperture modeling (Eqs. 1-7) provides a format for designing the nozzle such that the lateral velocity profile matches the laser beam lateral intensity profile, thereby providing uniform detection sensitivity to laser light scattered from monodisperse particles distributed laterally across the view volume. Uniform detection sensitivity of monodisperse particles provides accurate particle sizing resolution.
摘要翻译： 颗粒计数器（10）使载体气体或含有颗粒（72）的流体的样品流通过细长的扁平喷嘴（16）并流入由样品流和激光束的交点形成的视图体积（18） （13）。 携带在样品流中的颗粒在通过视图体积时散射光线。 散射光被光学系统（26）收集并聚焦到检测器（40）上。 来自检测器的信号的大小表示颗粒尺寸。 为了校正整个视图体积中的粒子速度和光束强度的差异，使用流动开度。 流量孔径建模（公式1-7）提供了一种用于设计喷嘴的格式，使得横向速度分布匹配激光束横向强度分布，从而对从分布在横截面上的单分散颗粒散射的激光提供均匀的检测灵敏度。 单分散颗粒的均匀检测灵敏度提供了精确的颗粒尺寸分辨率。
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9.发明授权Particles counting apparatus and method having improved particle sizing resolution 失效颗粒计数装置和方法具有改进的颗粒尺寸分辨率
公开(公告)号：US6016194A
公开(公告)日：2000-01-18
申请号：US113986
申请日：1998-07-10
CPC分类号： G01N15/1459 , G01N15/1425 , G01N2015/1075 , G01N2015/1087 , G01N2021/391
摘要： A particle counter (10) passes a sample stream of particles (72) through an elongated, flattened nozzle (16) and into a view volume (18) formed by an intersection of the sample stream and a laser beam (13). Scattered light (24) from the view volume is focused onto a linear array (32) of photodiode detectors (40) positioned such that a longitudinal length (70) of the view volume is imaged on the detectors. Because the sample stream produces nonuniform particle velocities along the longitudinal dimension of the view volume, for same-sized particles higher velocity particles will generate lower output amplitude signals than lower velocity particles. Therefore, the gain associated with each photo-detector element is adjustable to compensate for the nozzle velocity differences, laser beam intensity differences caused by beam divergence and fluctuations, optical path efficiency variations, and photo-detector element-to-element sensitivity differences.
摘要翻译： 颗粒计数器（10）使颗粒（72）的样品流通过细长的扁平喷嘴（16）并进入由样品流和激光束（13）的交点形成的视图体积（18）中。 来自视野体积的散射光（24）聚焦在光电二极管检测器（40）的线性阵列（32）上，定位成使视野体积的纵向长度（70）成像在检测器上。 因为样品流沿着视图体积的纵向尺寸产生不均匀的颗粒速度，对于相同尺寸的颗粒，较高速度的颗粒将产生比低速度颗粒更低的输出振幅信号。 因此，与每个光电检测器元件相关联的增益是可调节的，以补偿喷嘴速度差，由光束发散和波动引起的激光束强度差异，光路效率变化和光检测器元件到元件灵敏度差异。
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10.发明授权Particle counter employing a chromium based solid-state laser with an intracavity view volume 失效使用具有腔内视图体积的铬基固体激光器的粒子计数器
公开(公告)号：US5903347A
公开(公告)日：1999-05-11
申请号：US876136
申请日：1997-06-23
CPC分类号： G01N15/1434 , G01N15/1404 , G01N2021/391
摘要： A particle detector employs a resonant cavity having a chromium doped colquiriite crystal lasing medium, such as an Cr:LiSrAlF.sub.6 crystal, adjacent to an intra-cavity view volume. The resonant cavity is defined by two spaced apart mirrors, with the crystal positioned between them, defining a light path through the crystal, but most of the light does not escape past the mirrors. The view volume is positioned in the light path, between the first mirror and the laser medium, to introduce particles into the resonant cavity so that light impinging thereupon produces scattered light. A detector is disposed to sense light scattered from the view volume and produces signals proportional to the light sensed. Harmonic generators are used in alternate embodiments to produce sub-micron wavelengths. Optical coatings on mirrors forming cascaded cavities are used to isolate a harmonic wavelength in a cavity containing the view volume.
摘要翻译： 颗粒检测器采用具有与腔内观察体积相邻的铬掺杂的菱形闪烁体晶体激光介质如Cr：LiSrAlF 6晶体的谐振腔。 谐振腔由两个间隔开的反射镜限定，其中晶体位于它们之间，限定通过晶体的光路，但是大多数光不会通过反射镜。 视图体积位于第一反射镜和激光介质之间的光路中，以将颗粒引入谐振腔中，使得入射到其上的光产生散射光。 设置检测器以感测从视野体积散射的光并产生与所感测光成比例的信号。 在替代实施例中使用谐波发生器以产生亚微米波长。 使用形成级联空腔的镜子上的光学涂层来隔离包含视图体积的空腔中的谐波波长。
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