Surface-micromachined microoptical elements and systems

Optical systems are ubiquitous in the present-day societal fabric, from sophisticated fiber-optic telecommunication infrastructure to visual information display, down to mundane chores such as bar-code reading at the supermarket. Most of these existing systems are built from bulk optical components, as they have been for many years. Just as miniaturization and batch-process production have revolutionized electronics, similar advances in optics will certain greatly expand its applications and markets. Production techniques for optical systems that employ the emerging micro-electromechanical systems (MEMS) technologies give promise of achieving this success. Simple micromechanical fabrication techniques are already employed in fiber-optic components to produce what is generally described as silicon-optical-bench systems. New developments, especially those permitting the use of microactuated structures, make substantial increases in system sophistication possible. Surface micromachining, in which microoptical systems are batch-fabricated and placed on top of a silicon wafer, has become a promising approach to this progression. With the demonstration that surface-micromachined elements can be “folded” out from the plane in which they are constructed, an important new degree of design freedom has emerged. This paper examines some of the results obtained and attempts to project possibilities for surface micromachining in future optical systems     

台式电源的模块设计概念

现今，技术领先的电源公司在系统设计阶段就采用“模块设计方法”。某些医疗设备，包括数字和视频图像、数字Ｘ光机器、心电图监视器等都使用了模块电源设计概念。其优点在于加快面市时间，降低固定设备成本和降低电源单元的成本。     

A new concept of planar self-reconfigurable modular robot for conveying microparts

Modularity and self-healing are two interesting properties that could help to design more flexible conveyors of micro-objects. In the Smart Blocks project, we propose to design a 2D modular and self-reconfigurable robot composed of centimeter-scale sliding blocks that embed their own actuators and control electronics. This article presents a proof-of-concept of the linkage and of the traveling system as well as an algorithm able to reconfigure a set of blocks from a spatial configuration to another one. Prototype blocks have been realized using electro-permanent magnets which show a good motion speed while saving power consumption during the linkage. Our reconfiguration algorithm is implemented in a simulator software showing in real-time the reconfiguration of the robot.     

Novel active connector for modular robotic systems

In this paper, we present a novel concept for an active connector for electrical and mechanical connection of components of a robotic or electromechanical system called active connector for robotic systems (ACOR). ACOR consists of a plug and a receptacle that contain a plurality of flexible lamellae that serve as the connection/disconnection mechanism. A shape-memory-alloy actuator is used to move the lamellae endpoint and control in this way the connector engagement and disengagement. ACOR can transmit axial and shear forces and torque. The connector can be controlled from both the plug and/or the receptacle side. So, in the case of a module failure, it can be disassembled by sending signals to its neighbors. ACOR allows fully automatic operation, manual operation, and manual and automatic emergency access from the outside. There are two novel characteristics of ACOR, compared to other active connectors found in literature. First, it allows disconnection from either side of the connection, plug or receptacle, regardless of the power situation on the other side. Second, it has a very simple design since it is composed of a very small number of parts and components. In this paper, we present, in detail, the mechanical design, the analytical models for calculation of the transmitted forces/torques, and the SMA actuator force requirements, and the experimental prototype that was built to demonstrate the concept of the connector.     

Surface-micromachined micro-XYZ stages for free-space microoptical bench

Micro-XYZ stages have been monolithically integrated with microactuators and out-of-plane microoptical elements, all fabricated by the same surface-micromachined process, on Si free-space microoptical bench. Optical beam adjustment with three degrees of freedom has been realized without angular squinting. A positioning accuracy of 11 nm has been achieved by the integrated scratch drive actuators, with the travel distance larger than 30 /spl mu/m in each direction.     

Development of modular electrical systems

Modular systems provide the ability to achieve product variety through the combination and standardization of components. A methodology that combines system modeling, integration analysis, and optimization techniques for development of modular systems is presented. The approach optimizes integration and interactions of system elements and creates functional and physical modules for the electrical system. The Hatley/Pirbhai methodology (1987) is used for modeling functional requirements of a system. The model defines system interfaces (interactions) to support its functions. Once the interactions among functions are identified, an incidence matrix of the interfaces is developed. A clustering algorithm is developed to identify clusters in the incidence matrix, group the functions, and create modules. A Hatley/Pirbhai architecture model is developed to represent modular system design. A detailed discussion on the importance of system modeling in design of modular systems and on the constraints that limit development of modular vehicle systems is also presented. The approach presented is systematic and can be used to support product development and decision-making in engineering design     

综合模块化航空电子系统的故障预测与健康管理技术

航空电子系统是保障现代飞机性能的非常关键因素之一,对其开展故障预测及健康管理技术的研究是保证飞机安全性的重要课题。针对航空电子系统综合模块化的发展趋势,研究了一种面向其开放式与模块化架构的故障预测与健康管理系统。通过对综合模块化航空电子系统的分层结构分析,结合关键子系统展开设计,包含了飞机PHM系统的体系结构设计及相关环节的技术实现。结果表明该体系结构可满足航空电子系统标准化、层次化、模块化、开放性的要求。     

Realization of modular multidimensional complex digital filters using GIC concept

It is known that complex digital filters possess certain advantages over real digital filters in processing complex signals such as increased computational speed and efficiency. In this paper, a simple and systematic procedure which can be implemented through a computer program is presented for realizing a specific class of multidimensional (M-D) complex digital filters. The proposed filter structures are derived from analog reference configurations comprising generalized immittance converters and resistors by making use of wave concept. These filters possess many salient properties such as low noise, low sensitivity and capability of realizing multiple transfer functions simultaneously which are inherited from the reference analog filters they are derived from. These features make them attractive for very large-scale integrated (VLSI) implementation. It is shown that the proposed filter structures can be obtained directly from the specified M-D discrete transfer function without the need for realizing any analog reference configuration.     

A modeling and analysis methodology for modular logic controllersof machining systems using Petri net formalism

Logic controllers for machining systems typically have three control modes: auto, hand and manual. In this paper, a unified formal representation of logic controllers with three control modes is provided using Petri nets (PNs). A modular logic controller structure is introduced and formalized for high-volume transfer lines. The modular logic controller consists of one control module for the mode decision and other control modules for station logic controllers. Each station control module is represented by connecting together operation modules, which are designed with respect to the fault recovery processes of operations; their connection algorithm is also provided. In our formal representation, each control module is represented by a live, safe and reversible PN. A condition for the modular logic controller to generate a correct control logic is provided: the operation causality condition. Using the modular structure of a logic controller, the control logic can be easily reconfigured and automatic code generation is possible     

Plastic microoptical interconnection modules for parallelfree-space interand intra-MCM data communication

We design and fabricate a prototype scalable multichannel free-space interconnection module with the potential for Tb/s·cm ² aggregate bit-rate capacity over inter- and intra-MCM interconnection distances. The component is fabricated in a high quality optical plastic, PMMA, using deep proton lithography, an ion-based rapid prototyping technology. As a feasibility demonstration, data communication is achieved at 622 Mb/s per channel with a bit error rate smaller than 10^-13 for 16 channels with an interchannel crosstalk lower than -22 dB. We perform a sensitivity analysis for misalignments and fabrication errors and study the fabrication issues of these components with injection molding techniques. Finally, we provide evidence that these modules can be mass fabricated with the required precision     

A model for fast switching transients in power systems: the nearzone concept

The author presents a simple time-domain model which makes it possible to predict the order of magnitude of the highest di/ dt values generated by closing switches in electrical power systems. The model is based on traveling-wave analysis. It is demonstrated that two different approaches must be applied, according to whether (a) the closing time, T_s, of the switch is faster than twice the traveling time to the first reflection point or (b) T_s is much slower. Under condition (b) the well-known quasistationary approach di/dt_max=U₀/L can be used, where U₀ is the switched voltage and L is the self-inductance of the line between the stray capacitances located to the left and the right of the switching device. Under condition (a) a new formula must be applied: di/dt _max≈2 U₀/ZT_s, where Z is the line impedance of the line in which the switching device is installed and T_s is the time during which the voltage across the switch collapses from U₀ to zero. Experimental results are given from both fast and slow closing switches     

A modular bit-serial architecture for large-constraint-lengthViterbi decoding

A node-parallel Viterbi decoding architecture and bit-serial processing and communication are presented. An important aspect of this structure is that short-constraint-length decoders may be interconnected, without loss of throughput, to implement a Viterbi decoder of larger constraint length. The convolutional encoder trellis is modeled by appropriate wiring of decoder processing nodes: a variety of generating codes can be accommodated. Bit-serial communication links between nodes require only a single wire each and thus interconnection area is relatively small. During each decoding cycle, more than 50 b need to be communicated on each serial link and thus the technique is limited to moderate bit rate applications. A constraint length K=4 `proof of concept' chip was developed using 9860 transistors in 3 μm CMOS on a 4.51-mm×4.51-mm die size. The complete circuit operates at 280 kb/s and supports any rate 1/2 or 1/3 code with eight-level soft decision     

Large-area high-resolution lithography and photoablation systems for microelectronics and optoelectronics fabrication

An important requirement in the production of numerous microelectronic, optoelectronic, and microsystem devices is lithographic patterning on a large area with high image resolution and precise layer-to-layer alignment. Whereas for production of semiconductor devices advances have been steadily made in steppers and other conventional lithography systems, the lithography requirements for the fabrication of large-format products, such as displays, multilayer circuits, and flexible electronics, are distinctly different, rendering various conventional lithography tools inadequate. These requirements and distinctions of large-area lithography are discussed. In the last several years, we have developed a new class of projection lithography systems that provide both high-resolution imaging and very large exposure area capability with high-precision alignment. The systems, using excimer laser sources, function as dual-mode, high-throughput production tools, capable of patterning in photoresists as well as photoablation in polymers, making them attractive for production of numerous large-format products, with feature sizes ranging from 15 /spl mu/m to below 1 /spl mu/m and substrate sizes ranging from 150 /spl times/ 150 mm to 610 /spl times/ 915 mm. We review the new lithography system technology, several completed systems, and demonstrated results.     

Development of microoptical waveguide on microactuating platform technologies for reconfigurable optical networking

This paper reports on new hybrid optomechanical technology for reconfigurable optical networking applications. Unique and versatile functions in the technology were provided by micrometer-scale fused-taper waveguides mounted on microelectromechanical actuating platforms. The proposed technology can endow new degrees of freedom to control spectral response and port-to-port output power of the throughput of multiport fiber-fused-taper devices. Applications in a reconfigurable optical switch, an interband router, and a high-power optical attenuator for optical networking are discussed.     

A computer-controlled electron-beam machine for microcircuit fabrication

The main advantages of electron-beam methods for the fabrication of microcircuits are: 1) improvement in resolution; and 2) ease of automation. A computer-controlled electron-beam machine has been developed from a high-resolution scanning electron microscope and has incorporated several important features for use in microfabrication, such as an LaB6gun to improve brightness and stability, and a special electron collection system based on channel multipliers, which is particularly suitable for use with large flat specimens. The control system is based on a small general-purpose computer with a flexible data input facility which can be made compatible with the output of most computer-aided mask design facilities. The input data is based upon rectangular shapes but additional nonrectangular shapes can also be handled. Several of the important technical areas of the machine have been evaluated, e.g., resolution, speed of operation, area of coverage, etc. It has been found that speed of operation and area of coverage are both related to the beam diameter used and the effect of this rather complicated interrelationship has been studied. The machine has been used to generate patterns on mask and wafers and results indicate that it has direct application to microcircuit manufacturing and one immediate use would be to develop it into a mask maker where it could produce a complete set of standard size masks (1x) in one working day.     

A modular architecture for very large packet switches

Switch modules, the building blocks of this system, are independently operated packet switches. Each module consists of a Batcher sorting network, a stack of binary trees, and a bundle of banyan networks. The modular architecture is a unification of the Batcher-banyan switch and the knockout switch, and can be physically realized as an array of three-dimensional parallel processors. Switch modules are interconnected only at the outputs by multiplexers. The partitioned switch fabric provides a flexible distributed architecture, which is the key to simplify the operation and maintenance of the whole switching system. The modularity implies less stringent synchronization requirements and makes higher-speed implementation possible. The proposed modular switch is intended to meet the needs of broadband telephone offices of all sizes. It is estimated that a modular switch with terabit capacity can be built using current VLSI technologies     

Generic fault isolation concept for telecommunication systems in access networks

This paper presents an approach for a generic fault isolation (FI) concept for telecommunication systems in the access network area. Based on a distributed processor architecture, a universal software structure for a FI unit is proposed. It is able to isolate faults, field replaceable units and is easily portable to different hardware platforms. The reusability of the FI unit is achieved by separating the software into generic control functionality and fully hardware-dependent software parts, i.e. user configurable tables and hardware-dependent control routines. The implementation of the concept is discussed in a ‘fiber to the building’-system which has already entered into mass-production. © 1997 John Wiley & Sons, Ltd.     

Optimization of automated high-speed modular placement machinesusing knowledge-based systems

This paper introduces an optimizer for a new family of modular, multistation, walking beam, high-speed chip mounters. The objective is to optimize the machines in a manner that would streamline the use of nozzles and part feeder mechanisms and at the same time increase throughput. The optimization of these machines is a large NP-complete problem, and therefore, a heuristic search method is needed to solve the problem in reasonable time. Four knowledge-based systems are introduced to solve this problem. These systems were designed to emulate human experts, who have optimized these types of machines manually. Benchmarks were performed for 18 industrial test cases. The results show that overall, the knowledge-based systems outperformed software supplied by the vendor of the machine in both feeder slot savings and throughput. This performance represents a key improvement, and a prototype system has been implemented in our industrial partner's factory