公开(公告)号：US06285002B1

公开(公告)日：2001-09-04

申请号：US09307710

申请日：1999-05-10

Applicant: Bryan Kok Ann Ngoi ,  Krishnan Venkatakrishnan

Inventor： Bryan Kok Ann Ngoi ,  Krishnan Venkatakrishnan

IPC: B23K2606

CPC classification number: G03F7/202 ,  B08B7/0042 ,  B23K26/0624 ,  B23K26/066 ,  B23K26/0736 ,  B23K26/08 ,  B23K26/082 ,  B23K26/382 ,  G02F1/33

Abstract: A technique and apparatus is disclosed for micro machining using an ultra short laser pulse in the range of femto second pulsing. The system is also applicable for smaller or higher pulse rates depending upon the application. The system includes methods for improving the beam quality of the laser beam by filtering. Moreover, it includes the concept of scanning the laser beam using acousto optic deflectors in the X-Y direction rather than conventional mechanical movement of the work piece or deflecting the beam using a mirror. The technique also incorporates means for modulating the ultra short laser pulse in order to control the number of pulses of the ultra short laser pulse which will strike the target surface at each of the target points by a combination of acousto optic modulators. The concept of applying elliptical or circular laser beam spots for machining rather than a circular one is also disclosed.

Abstract translation: 公开了一种使用在毫微微秒脉冲范围内的超短激光脉冲进行微加工的技术和装置。 根据应用，该系统也适用于较小或更高的脉率。 该系统包括通过滤波来改善激光束的光束质量的方法。 此外，它包括在X-Y方向上使用声光偏转器扫描激光束的概念，而不是常规的工件机械运动或使用反射镜偏转光束。 该技术还包括用于调制超短激光脉冲的装置，以便通过声光调制器的组合来控制将在每个目标点处撞击目标表面的超短激光脉冲的脉冲数。 还公开了用于加工椭圆形或圆形激光束点而不是圆形激光束点的概念。

公开(公告)号：US06271924B1

公开(公告)日：2001-08-07

申请号：US09222731

申请日：1998-12-29

Applicant: Bryan Kok Ann Ngoi ,  Krishnan Venkatakrishnan

Inventor： Bryan Kok Ann Ngoi ,  Krishnan Venkatakrishnan

IPC: G01B902

CPC classification number: G01B11/14 ,  G01B9/02003 ,  G01B2290/60 ,  G01B2290/65 ,  G01B2290/70 ,  G01H9/00 ,  G11B33/10

Abstract: A technique and apparatus for non-contact scanning measuring of the dynamic parameters of micro and macro devices using an acousto optic scanning laser vibrometer are disclosed. The system includes an acousto optic deflector to induce scanning in the laser beam. The apparatus also includes either a heterodyne or homodyne system for laser scanning. The heterodyne detection technique involves two acousto optic deflectors driven by a common signal generator. The invention may include an interference technique in which the measuring scanning beam emitted by the acousto optic deflector interferes with the reference-scanning beam. For some applications, this acts as a second measuring beam. With this technique, the frequency shift induced in the laser beam on scanning with the acousto optic deflector is canceled due to fact that the two acousto optic deflector are of same specification and driven by a common driver. The invention may also include an apparatus and technique for homodyne detection. A method adopting single and double acousto optic deflectors in the optical layout is also disclosed for homodyne detection system. The technique also incorporates two axes scanning. The invention may include a computer controller to control the scanning parameters and the data capturing parameters simultaneously. This technique incorporates a parallel scanning beam of small spot size for the purpose of micro device inspection in optical head, hard disk, micro components, etc. The use of the invention for measurement of least fly-height information in hard disk by double axis scanning is also disclosed. The method and apparatus for applying the invention to measuring the dynamic parameters of rotating targets and eliminating the error induced due to pseudo vibration noise is also disclosed.

Abstract translation: 公开了一种使用声光扫描激光测振仪测量微型和微型装置的动态参数的非接触式扫描的技术和装置。 该系统包括声光偏转器以在激光束中感应扫描。 该装置还包括用于激光扫描的外差或零差系统。 外差检测技术涉及由公共信号发生器驱动的两个声光偏转器。 本发明可以包括干涉技术，其中由声光偏转器发射的测量扫描光束干扰参考扫描光束。 对于某些应用，这充当第二个测量光束。 利用这种技术，由于两个声光偏转器具有相同的规格并由普通驱动器驱动的事实，消除了用声光偏转器扫描的激光束中感应的频移。 本发明还可以包括用于零差检测的装置和技术。 还公开了在光学布局中采用单声道和双声道偏转器的方法，用于零差检测系统。 该技术还包含两个轴扫描。 本发明可以包括同时控制扫描参数和数据捕获参数的计算机控制器。 该技术采用小光斑尺寸的平行扫描光束，用于光学头，硬盘，微型部件等微器件检测。本发明用于通过双轴扫描测量硬盘中的最小飞行高度信息 也被披露。 还公开了用于测量旋转靶的动态参数并消除由于伪振动噪声引起的误差的方法和装置。

公开(公告)号：US06307799B1

公开(公告)日：2001-10-23

申请号：US09204555

申请日：1998-12-03

Applicant: Bryan Kok Ann Ngoi ,  Krishnan Venkatakrishnan

Inventor： Bryan Kok Ann Ngoi ,  Krishnan Venkatakrishnan

IPC: G11C1304

CPC classification number: G11C13/04 ,  G11B7/0033 ,  G11B7/0037 ,  G11B7/08558 ,  G11B7/0901

Abstract: A miniaturized stationary optical storage system capable of reading and writing data on an optical storage media is disclosed. In the disclosed invention, the disk is held stationary and the beam is made to scan on both the axes by using an acousto optic technique. The preferred embodiment has a technique of obtaining parallel scanning beam, which is focused on to the optical storage media and the photo detector receives the reflected beam carrying the optical signal. The system has the capability of reading as well as writing on the optical storage media by using the same source or different source. The preferred embodiment also utilizes square as well as circular optical storage media of reduced size, which is achieved, by adopting smaller spot size and higher scanning resolution. The method of magnifying the scan angle of the scanning beam from the acousto optic deflector is also disclosed. The alternative embodiment utilizes phase shifting for reading the signal rather than the intensity of the signal.

Abstract translation: 公开了一种能够在光学存储介质上读取和写入数据的小型化的静态光学存储系统。 在所公开的发明中，盘被保持静止，并且通过使用声光技术使光束在两个轴上扫描。 优选实施例具有获得平行扫描光束的技术，该扫描光束聚焦于光学存储介质，并且光电检测器接收携带光信号的反射光束。 该系统具有通过使用相同的源或不同的源读取和写入光存储介质的能力。 优选实施例还采用减小尺寸的方形以及圆形光学存储介质，其通过采用较小的斑点尺寸和较高的扫描分辨率来实现。 还公开了从声光偏转器放大扫描光束的扫描角度的方法。 替代实施例利用相移来读取信号而不是信号的强度。

公开(公告)号：US06555781B2

公开(公告)日：2003-04-29

申请号：US09898454

申请日：2001-07-05

Applicant: Bryan Kok Ann Ngoi ,  Krishnan Venkatakrishnan

Inventor： Bryan Kok Ann Ngoi ,  Krishnan Venkatakrishnan

IPC: B23K2606

CPC classification number: B23K26/382 ,  B08B7/0042 ,  B23K26/0624 ,  B23K26/066 ,  B23K26/0736 ,  B23K26/08 ,  B23K26/082 ,  B23K26/40 ,  B23K2101/35 ,  B23K2103/08 ,  B23K2103/26 ,  B23K2103/50 ,  G02F1/33 ,  G03F1/76 ,  G03F7/202

Abstract: A method and apparatus for precision laser scanning suitable for precision machining or cleaning using an ultrashort pulsed laser beam are disclosed. The apparatus employs a laser source that emits a pulsed laser beam, a dispersion compensation scanner that scans the pulsed laser beam, and a focusing unit that focuses the pulsed laser beam from the dispersion compensation scanner on a work piece. The dispersion compensation scanner comprises a first scanning device that scans the pulsed laser beam in a first direction and that causes dispersion of the pulsed laser beam. The dispersion compensation scanner further comprises a first dispersion compensation device that compensates for the dispersion caused by the first scanning device. Effects of polarization of the ultrashort pulsed laser beam on the quality of machining are described. Uses of the invention in direct fabrication of photolithographic masks and in work piece cleaning are also described.

公开(公告)号：US06525331B1

公开(公告)日：2003-02-25

申请号：US09452160

申请日：1999-12-01

Applicant: Bryan Kok Ann Ngoi ,  Fan Hua

Inventor： Bryan Kok Ann Ngoi ,  Fan Hua

IPC: G01N2186

CPC classification number: G01N21/8806

Abstract: A method and apparatus is disclosed for non-contact, on-line inspection of objects including a ball grid array package by means of a shadow moiré technique combined with a novel flash phase-shifting method. The grid pitch size, ball height, ball diameter, missing ball, coplananity can be determined or measured within several seconds. The apparatus includes a camera for viewing the object, a plurality of light sources arranged in a line for illuminating the object to be inspected, a frame grabber for capturing images of the object, an I/O adapter card for controlling the light sources and a personal computer for data processing. The individual components are integrated into system which provides a three dimensional map which is obtained quantitatively using a novel algorithm. The system can provide coplananity data, as well as data relating to grid pitch, ball height, ball diameter, and missing ball information.

Abstract translation: 公开了一种方法和装置，用于通过与新颖的闪相移相方法结合的阴影莫尔技术进行非接触式在线检查，包括球栅阵列封装。 网格间距大小，球高度，球直径，缺球数，共同性可以在数秒内确定或测量。 该装置包括用于观看对象的照相机，布置成用于照亮待检查物体的线的多个光源，用于捕获物体的图像的帧抓取器，用于控制光源的I / O适配器卡和 个人电脑进行数据处理。 各个组件被集成到系统中，其提供了使用新颖算法定量获得的三维图。 该系统可以提供协调性数据，以及与网格间距，球高度，球直径和丢失球信息相关的数据。

公开(公告)号：US06320665B1

公开(公告)日：2001-11-20

申请号：US09350901

申请日：1999-07-12

Applicant: Bryan Kok Ann Ngoi ,  Krishnan Venkatakrishnan

Inventor： Bryan Kok Ann Ngoi ,  Krishnan Venkatakrishnan

IPC: G01B902

CPC classification number: G01B11/14 ,  G01B9/02015 ,  G01B2290/70 ,  G01H9/00 ,  G11B5/6052 ,  G11B33/10

Abstract: An apparatus and method for using an acousto optic scanning laser vibrometer for measuring a dynamic parameter of micro and macro components is disclosed. A coherent source of a laser beam of single wavelength and of stabilized frequency is split into two orthogonal polarized beams. One of the beams strikes the surface of investigation and gets reflected back, and the other polarized beam impinges on the reference surface and gets reflected back. The beam reflected from the surface of investigation and the beam from the reference surface are combined, thereby causing them to interfere. At least one photo detector is positioned at the point of interference. The photo detector output signals are input to a signal processor or phase meter to obtain the dynamic parameter information. Information is provided that is based on the phase shift between the beam striking on the object of investigation and the beam striking the reference surface due to the difference in the optical path. The information provided relates to the dynamic parameters of the object under investigation.

Abstract translation: 公开了一种使用声光扫描激光测振仪测量微观和微观组件的动态参数的装置和方法。 单个波长和稳定频率的激光束的相干光源被分成两个正交偏振光束。 其中一个光束撞击到调查表面并被反射回来，另一个偏振光束照射在基准面上并被反射回来。 从研究表面反射的光束和来自参考表面的光束被组合，从而使它们干涉。 至少一个光电检测器位于干涉点。 光检测器输出信号被输入到信号处理器或相位计，以获得动态参数信息。 提供了基于由于光路的不同导致的撞击物体上的光束与射入基准面的光束之间的相移的信息。 所提供的信息涉及被调查对象的动态参数。

公开(公告)号：US06195208B1

公开(公告)日：2001-02-27

申请号：US09421539

申请日：1999-10-20

Applicant: Bryan Kok Ann Ngoi ,  Zhou Xiaoqun ,  Koh Soon Seong

Inventor： Bryan Kok Ann Ngoi ,  Zhou Xiaoqun ,  Koh Soon Seong

IPC: G02B2730

CPC classification number: G02B27/09 ,  G02B19/0014 ,  G02B19/0052 ,  G02B27/0955

Abstract: An astigmatic and non-circular diverging input laser beam is converted into a collimated and circular output laser beam with its astigmatism corrected using a single aspherical lens. The input surface has a concave aspherical profile in the transverse direction and a convex aspherical profile in the longitudinal direction respectively for astigmatism correction. The output surface has a convex aspherical profile in the transverse direction and a non-curved profile in the longitudinal direction respectively for collimation and circularization of the final output laser beam.

Abstract translation: 散光和非圆形发散输入激光束被转换为准直和圆形的输出激光束，其散光使用单个非球面透镜进行校正。 输入表面在横向具有凹非球面轮廓，并且在纵向方向上具有凸非球面轮廓，用于散光校正。 输出表面在横向上具有凸非球面轮廓，并且在纵向上具有非弯曲轮廓，用于最终输出激光束的准直和圆化。

公开(公告)号：US06710881B1

公开(公告)日：2004-03-23

申请号：US09407177

申请日：1999-09-28

Applicant: Bryan Kok Ann Ngoi ,  Krishnan Venkatakrishnan

Inventor： Bryan Kok Ann Ngoi ,  Krishnan Venkatakrishnan

IPC: G01B902

CPC classification number: G01B9/02007 ,  G01B9/02022 ,  G01B9/02025 ,  G01B9/02057 ,  G01B2290/70

Abstract: A system and method for high speed and precision measurement of the distance between at least two near contact surfaces using heterodyne interferometry is disclosed. One of the surfaces is an optically transparent element and the other surface is a substantially non-transparent element. A laser source produces an output having two superimposed orthogonally polarized beams having S and P polarization, with a frequency difference between them. The polarized beams are split into measurement and reference beams without altering the characteristics of the polarized beams. The reference beams are caused to interfere, and a reference photo detector detects the reference beams and provides a reference signal. The measurement beam strikes the object of interest at an oblique angle after passing through a glass plate having a polarization coating on the bottom surface close to the object of interest. The oblique angle is such that the S polarization of the incident beam is reflected from the bottom surface of the polarization coated glass plate and the P polarization refracts through the glass plate. The P polarization reflects from the substantially non-transparent object of interest and refracts to the glass plate. The reflected S and P polarization beams from the bottom surface of the glass plate and the surface of the object are made to interfere. A measurement photo detector detects the measurement beams and provides a measurement signal. The distance between the bottom surface of the glass disk and the object surface based on the phase deference between the measurement and reference signals is determined from the measurement and reference photo detectors.

Abstract translation: 公开了一种用于使用外差干涉测量来高速和精确地测量至少两个近接触表面之间的距离的系统和方法。 其中一个表面是光学透明的元件，另一个表面是基本不透明的元件。 激光源产生具有两个具有S和P偏振的叠加的正交偏振光束的输出，它们之间具有频率差。 偏振光束被分成测量和参考光束，而不改变偏振光束的特性。 参考光束被干扰，参考光电检测器检测参考光束并提供参考信号。 测量光束穿过具有靠近感兴趣物体的底面上的偏振涂层的玻璃板之后以倾斜的角度撞击目标物体。 倾斜角度使得入射光束的S偏振从偏振涂覆的玻璃板的底表面反射，并且P偏振通过玻璃板折射。 P极化从基本上不透明的物体反射并折射到玻璃板。 来自玻璃板底表面和物体表面的反射的S和P偏振光束被干扰。 测量光电检测器检测测量光束并提供测量信号。 从测量和参考光电检测器确定基于测量参考信号之间的相位差的玻璃盘的底表面与物体表面之间的距离。