The objective lens is a single element glass lens with one aspheric replicated surface and one flat surface. The manufacture of the aspheric surface by means of replication is suitable for high quality mass-production.

Gas lasers have shown to be capable of delivering tens of terrawatt aspeak power or tens of kilowatt as average power. The efficiencies of most high power gas lasers are relatively high compared with other types of lasers. For instance molecular lasers,oscillating on low lying vibrational levels, and excimer lasers may have intrinsic efficiencies above 10%. The wavelengths of these gas lasers cover the range from the far infrared to the ultra-violet region, say from 12000 to 193 nm. The most important properties are the scalability, optical homogeneity of the excited medium, and the relatively low price per watt of output power. The disadvantages may be the large size of the systems and the relatively narrow line width with limited tunability compared with solid state systems producing the same peak power.

The manufacture of advanced ceramic components requires high accuracy and repeatibility in the control of the fabrication process. Surface finish in the nanometer range and excellent figure accuracy can be achieved if material can be removed from the surface without causing brittle fracture. To define the mechanism of "ductile" material removal, a series of experiments were initiated involving two processes: single-point diamond turning and diamond-wheel grinding. The results indicate that at small depths of cut, using stiff, well controlled machine tools, ceramic materials like silicon, silicon carbide, and germanium can be machined in a ductile regime.

The feasibility of using micromechanical silicon cantilever beams for optical switching is under examination. These devices are easy to interface to optical fibres and could easily incorporate monitoring circuitry. They potentially offer several advantages over solid state electro-optical devices including small size, low fabrication cost and compatibility in size with optical fibres. In addition, control and monitoring coula readily be incorporated on the same chip, perhaps exploiting the anisotropic etching feature to further advantage. Their speed limitation is not a disadvantage in applications where the determining factor is the initial setting up time for the connection. This investigation has been concerned with the design and fabrication of vertical beams in (110) silicon wafers. The present work is aimed at evaluating silicon technology to assess the feasibility and define the parameters for an optical switch design. A numerical simulation of the deflection and damping characteristics of the beam has been carriea out and has identified a range of design parameters which could be useful for optical switching. A range of devices having a first resonant frequency of >5kHz and a beam deflection of ~20μm have been designed. The fabrication procedure employs conventional silicon planar technology to define the beam geometry on (110) wafers. The structures are etched using electrochemically controlled ethylene-diamine as an anisotropic etchant. The fabrication of these vertical beams involves a combination of micromaching and silicon planar technology to align the beams accurately along <112> directions.

Gridded reflectors are used on communication satellites antennas to provide frequency reuse in dual linear polarisation mode of operation. The polarisation sensitive surface consists of metallic strips, forming a grid with width and spacings of the order of 0.1 mm. The use of frequency-selective surface (FSS) subreflectors allows the simultaneous generation of different microwave beams with the same main reflector. Such a reflector will require a structure of conductive arrays of either dipoles, rings, squares or square loops with typical dimensions of the order of 3-6 mm. Optimisation of the electrical design leads to critical dimensioning of these structures. By direct ablation of an aluminium surface coating by means of laser evaporation, high accuracies can be achieved. The major requirements were to minimize thermal damage of the substrate material and to produce dimensionally accurate grids. Experiments were carried out using a pulsed TEA-CO2 laser and a Q-switched Alexandrite laser. Details of the experimental set-up and conditions are described.

Micromachining of mechanical structures by ion bombardment is reported. A 1.5 kV argon ion beam is used under computer control for workpiece stock removal. Generation of profiles with submicron precision is demonstrated and computer algorithms are used to predict machining conditions for producing specific surface characteristics and evaluating them geometrically.

Small steel moulds for injection moulding of polymer lenses are precision ground at Philips Research Laboratories. As part of a broader research program the relations between the process parameters and the generated surface roughness are investigated. A computer simulation technique used to investigate these relations is described. This technique allows us to investigate the effects of grinding wheel and workpiece geometries and of grain size, distribution and concentration. Process parameters such as depth of cut, infeed, and angular velocities can be chosen. The effects of initial workpiece roughness and of multiple passes of the grinding wheel over the surface can be investigated. Unbalance of the grinding wheel can also be taken into account. A simple geometrical model is used to calculate the shape of the scratches made by grains engaging the workpiece. The wear behaviour of grains can be taken into account assuming a simplified wear law. Some results of these simulations are presented. Predicted trends are compared with experimental results.

The accuracy of air bearing systems is related in most cases to the static stiffness of the bearing. In practice the stiffness which can be achieved is related to the selection of optimum design parameters. This paper considers journal bearings and discusses the parameters which control bearing performance. Guidance is given to assist the designer in specifying the optimal conditions of each controlling parameter. A graphical design procedure is discussed which enables the designer to interrelate all aspects of design in a simple to use technique whilst still retaining optimal ranges for each parameter involved.

Internal Diameter Sawing is the common used technique for slicing hard and brittle materials, such as semiconductive Silicon, Germanium or ceramics and glasses. Nevertheless, productivity and yield are relative low due to the difficult handling of the flexible tool. Increasing workpiece dimensions lead to increasing problems in realizing quality requirements, such as high flatness, low roughness and low crystal damage. The report deals with basic relationships in I D-Sawing, irrespective of workpiece material (geometry and kinematics) as well as respective to monocrystalline Silicon (cutting mechanism, lattice damage, flatness). Finally guidelines are given to improve process reliability.

By a combination of X-ray lithography, galvanoforming and molding processes, microstructures with lateral dimensions in the micrometer range, vertical dimensions of some hundred micrometers and submicrometer tolerances have been produced. An analysis of precision and surface quality achievable by this technique is given and design studies of various microoptical components are presented.

A disscussion of the factors of the manufacture and use of single crystal diamond tipped tools in micro-machining optical quality products. Includes a disscussion of tolerance available, tool design problems, materials that can be machined with diamond and means of maximizing the life and usefulness of diamond tools.

The requirements for surface quality of workpieces such as metaloptics are increasing, specially if they are used as mirrors in high energy laser system- The precision of figure, slope errors, and surface roughness depend on the performance of the machining process. These facts determine the development of precision and ultraprecision machines. Various parameters influence workpiece quality machined with a single point diamond tool: machine behaviour, technology and environmental factors. esearch work. have demonstrated, that specially the static and dynamic behaviour of ultraprecision machines decisively determines optical surface quality. An improved measurement technique to analyse the static and dynamic behaviour of those machines is presented. The discussion of results from ultraprecision machine tests demonstrated, that it is possible to combine the measured vibration amplitude at the tool during the process with the generated surface texture on the workpiece. The goal of research work today is to find out a measuring approach of machined surfaces, which contents the analysing of the machine tool behaviour. The man in the shop floor will be able to improve the machining process by comparing real and synthetic interferograms. Checking systematic interferogram lists, which content advices of faulty machining parameters, it is possible to get get informations, how to change the machining parameters.

Micromachining of precision elements requires an adequate machine concept to meet the high demand of surface finish, dimensional and shape accuracy. The Hembrug ultra precision lathes have been exclusively designed with hydrostatic principles for main spindle and guideways. This concept is to be explained with some major advantages of hydrostatics compared with aerostatics at universal micromachining applications. Hembrug has originally developed the conventional Mikroturn ultra precision facing lathes, for diamond turning of computer memory discs. This first generation of machines was followed by the advanced computer numerically controlled types for machining of complex precision workpieces. One of these parts, an aerostatic bearing component has been succesfully machined on the Super-Mikroturn CNC. A case study of airbearing machining confirms the statement that a good result of the micromachining does not depend on machine performance alone, but also on the technology applied.

Air bearing machine tools need dynamic testing for evaluation and qualification. To do this with low cost, high speed and sufficient accuracy three excitation possibilities: impuls, sinus and the process itself are outlined and five sensor possibilities (three types of accelerometers and two types of distance-sensors) are described together with the respective draw-backs. Typical results are presented.

Random process analysis of component surface finish data is used to establish the 'fingerprint' of the machine tool condition when applied to a particular machining operation. Vibrations occurring during the machining process can be determined and the nature of the vibration isolated. It will be shown that for a turning operation it is possible to distinguish among types of error, such as, vibrations and errors causing radial movement of the cutting tool, variation in feed rate, vertical vibration of the cutter or component, or worn bearings. Existing methods used for condition monitoring involve the use of expensive vibration analysers with skilled personnel to assess the results and make a judgement of the machine tool capability. This means that a machine must be taken off line to be checked and hence cannot be continually assessed. Random process analysis of the surface texture produced on the component permits condition monitoring and assessment of machine capability to be made during production runs. The control parameters are not based on an arbitary judgement but on maintaining an acceptable quality of component according to its specification. This method effectively closes the control loop closely around the component. It modifies the control parameters to meet the required precision for the component and assesses if the machine capability is acceptable.

It is generally accepted, that optical methods are the most promising for the in-process measurement of surface finish. These methods have the advantages of being non-contacting and fast data acquisition. Furthermore, these optical instruments can be easily retrofitted on existing machine-tools. In the Micro-Engineering Centre at the University of Warwick, an optical sensor has been developed which can measure the rms roughness, slope and wavelength of turned and precision ground surfaces during machining. The operation of this device is based upon the Kirchhoff-Fresnel diffraction integral. Application of this theory to ideal turned and ground surfaces is straightforward, and indeed the calculated diffraction patterns are in close agreement with patterns produced by an actual optical instrument. Since it is mathematically difficult to introduce real machine-tool behaviour into the diffraction integral, a computer program has been devised, which simulates the operation of the optical sensor. The program produces a diffraction pattern as a graphical output. Comparison between computer generated and actual diffraction patterns of the same surfaces show a high correlation. The main aim of this program is to construct an atlas, which maps known machine-tool errors versus optical diffraction patterns. This atlas can then be used for machine-tool condition diagnostics. It has been found that optical monitoring is very sensitive to minor defects. Therefore machine-tool detoriation can be detected before it is detrimental.

The quality of optical surfaces generated by single-point diamond machining has been evaluated for laser printing applications. Microfinish topography of the surfaces has been analyzed by differential bidirectional laser scattering. Random and periodic surface structure, derived from the Fourier transform of the scattered-light power spectrum, are compared with interferometric surface roughness measurement. Surface tolerance may be specified for a class of laser printers by comparing the scattered intensity distribution with the analytical model of image degradation due to optical scattering. Roughness parameters have also been characterized as a function of tool radius and feed rate. Surface flatness and relative surface parameters are measured for a polygonal laser deflector. Measurement techniques are described. The characteristics of some commercially supplied micro-machined optics are discussed.

The performance of a dimensional surface-measuring instrument is usually limited by a small number of critical components or specifications. For example, parameters such as those specifying ranges and resolutions, and probe geometry are needed to define the capabilities of the instrument. The response of the instrument to sinusoidal perturbations of varying amplitude and wavelength, can be mapped in amplitude-wavelength space to show the effect of each parameter and the overall limits of performance.

Table motion systems of high precision machines combine several properties, such as very good displacement accuracy and repeatability, small straightness errors of slides and realization of constant velocities. According to these demands special elements are applied, for example high precision slide systems, linear drive systems and metrology systems. A survey about the properties of these elements will be given.

The writing performance of ball pens can be further improved. New or refined testing and measuring techniques have clearly shown that substantial benefits can be derived from mechanical perfection. This involves developing single-purpose machines for ultraprecision forming of cutting tools, for high speed production machinery capable of producing ball pen writing points with a minimum of uncertainties. It also involves testing equipment for the materials. However, the aim is to reduce manufacturing costs and simplify production.

The Digital Piezo Transducer (DPT) is a piezo-electric actuator incorporating a capacitance micrometer as an integrated position sensor. This internal micrometer has a positional resolution which is much better than a nanometer. The DPT is operated in a closed servo-loop incorporating an almost perfect integrator stage. As a result the DPT is extremely stiff and is capable of sub-nanometer resolution and stability. It has a response time of better than 1 millisecond and a maximum range of 120 um.