MOEMS packing architecture has been a major driving force for miniaturization of fiber optical components and optical communication devices. By using of bulk micromachining technology, V-grooves and micro-pits can be fabricated on a silicon wafer for coupling micro laser diode to fiber or fiber to fiber, and finally integrating into the small modules on chip packages. Because many factors, such as photolithography, material property, wet chemical etching process and operator's skills will influence the geometric accuracy, a precision measurement instrument is needed for in-situ inspection of V-grooves suitable for the critical passive optical alignments. This paper reported a novel 3D confocal profile measurement system for in-situ inspection of the depth of multi-channel V-grooves.
Confocal 3-D imaging technique is a newly developed technique and widely used in many fields of research and development. It is to utilize light intensity sensitive measuring technique. Confocal 3-D profile measurement system is widely used in high resolution inspection. For high precision 3-D imaging inspection in confocal measuring system, light source acts a very important role in system resolution and accuracy. In order to improve measuring repeatability and stability, to reduce measurement error, and to lower the light source stability requirement and cost, this paper studied light source fluctuation effect to confocal imaging measurement; deduced depth response model function; analyzed system error caused by light source fluctuation; and presented a new scheme to reduce the affection of light source fluctuation. Theoretical analysis and experiment result verified that light source fluctuation should be considered and eliminated in very high resolution confocal 3-D shape measurement system.
3-D profile confocal optical microscopy is a newly developed 3-D profile metrology and has widely applied in many kinds of 3-D shape inspection fields. Present 3-D shape measurement system used in confocal optical microscopy is single point measurement. Point by point detection to finish a 3-D profile inspection is considered a time consuming method and isn't suitable for large area measurement especially for high resolution measurement. This paper elaborated on a fiber-array confocal 3-D imaging system to improve measuring speed. In confocal measurement system, light source acts an important effect on system accuracy and repeatability. Light source fluctuation can cause a large error for high resolution 3-D shape measurement. This paper presents a novel system construction to solve the problem of light source fluctuation. The system design is compact and the construction is reasonable.
Laser Doppler Anemometry (LDA) is a most advanced velocity measurement technique in the field of fluid mechanics, combustion, hydraulics, chemical engineering, meteorology, biomedicine engineering and industrial manufactory for its non-contact, high response, and real-time velocity measurement. In LDA technique, optical signal processing is very important and very complex due to complicated flowing properties of fluid. LDA system includes optical section and signal processing section. In conventional LDA system, these two sections are separated and perform their own functions individually. Because optical section has no active control to measured signal, only mechanically indicates the variation of measured signal, the signal processing section was designed complex and costly. The existed signal-processing methods have different problems which limited the application and in turn increasing the difficulty of signal processing to detect the complex fluid. This paper describes and analyzes a new technique, C/T technique which combined optical section and signal processing section together, made the output signal simpler and solved the problems occurred in tradition methods. On the basis of analysis of C/T method, system construction is described.
With the increasing demand for micro-products and bioengineering research, resolutions of profiles with micrometer or even nanometer scale are becoming commonplace. In addition development of large integrated manufacturing systems and the real time life science growth and adaptation need high-speed display and real-time inspection. Single point measurement is time consuming method with large area profile and micrometer resolution. Thus there is a need for a fast 3-D measurement system with high resolution. This paper presents a short overview among optical 3-D shape measurement techniques, and concentrates on the confocal method. Based on the properties analysis, a novel multi-channel 3-D topography measurement system was proposed. The feasibility and the construction of system were described A unique new structure of fiber coupled confocal system is put forth to solve present problems confronted in confocal system. This system can meet the current demand of high resolution and fast 3-D measurement.
Moire method is an effective way to measure full field deformation. In this paper, the atomic force microscope scanning moire method and micro-moire interferometry method are proposed to determine the deformation in micro-area. The measurement principle and techniques are discussed. The two methods are applied to measure thermal deformation in a BGA (ball grid array) electronic package component. The shear strain (gamma) xy at the solder site is determined. The experimental results including the adaptability of these two methods are compared and analyzed. The results show that AFM scanning moire and micro-moire interferometry methods are effective ways to measure the deformation in micro-area with high sensitivity.