Quality standards are very high in carriage manufacturing, due to the fact, that the visual quality impression is highly relevant for the purchase decision for the customer. In carriage parts even very small dents can be visible on the varnished and polished surface by observing reflections. The industrial demands are to detect these form errors on the unvarnished part. In order to meet the requirements, a stripe projection system for automatic recognition of waviness and form errors is introduced¹. It bases on a modified stripe projection method using a high resolution line scan camera. Particular emphasis is put on achieving a short measuring time and a high resolution in depth, aiming at a reliable automatic recognition of dents and waviness of 10 μm on large curved surfaces of approximately 1 m width. The resulting point cloud needs to be filtered in order to detect dents. Therefore a spatial filtering technique is used. This works well on smoothly curved surfaces, if frequency parameters are well defined. On more complex parts like mudguards the method is restricted by the fact that frequencies near the define dent frequencies occur within the surface as well. To allow analysis of complex parts, the system is currently extended by including 3D CAD models into the process of inspection. For smoothly curved surfaces, the measuring speed of the prototype is mainly limited by the amount of light produced by the stripe projector. For complex surfaces the measuring speed is limited by the time consuming matching process. Currently, the development focuses on the improvement of the measuring speed.

Why do we need to characterize surfaces and specially scattering of surfaces? In many industries including the automotive industry, interaction of light with materials is very important, in headlamps, tail lamps, dashboards, and the optical simulations made by designers, developers with their illumination design software, their realistic rendering software need scattering data to perform simulations and get results. Unfortunately, only theoretical data are available right now, and simulation results are not relevant of reality. It is why we have developed the REFLET Bench to answer all these problems.

In this paper a new concept of a hybrid Opto-Mechanical Measurement Machine (OMMM) is presented. This concept combines advantages of the high accuracy contact CMM and the high measurement speed non-contact optical techniques. OMMM is developed for measurement of large-size elements, especially for the automotive industry. It introduces high-speed and high-accuracy measurement procedure which is performed in four steps: 1) optical structured-light measurement of the entire surface, 2) analysis of model parts, determination which area should be re-measured with higher accuracy, 3) measurement with a CMM, 4) final metrological data analysis. Data gathered by such a system are compared with the CAD model of the object, thus allowing automatic error control of every manufactured product.

Innovations in photonics technology have the potential to revolutionize both the inside and the outside of the automobile, making driving, simpler, safer, and more economical. Some of the most interesting applications areas are: lighting, communications, night vision, display, entertainment, and controls. However, the commercialization of these technologies will depend on a number of factors: cost, proven improvements in safety, economy of operation, availability of mass-produced components with high uniformity and reliability, regulations, and standards. The automotive industry recognizes the utility of a roadmap to focus all players, from basic device manufacturing and component integrators, to set manufacturers and ultimately automotive assemblers. In this paper we report on progress on an important component of this roadmap concerning adaptive front-lighting systems (AFS).

In this paper we propose a one step marking process using a high power near infrared fiber laser and diffractive optical elements or gratings as an alternative to traditional scanning systems. The impact of the gratings fill factor, the power level on the diffracted beams and the quality of the reconstructed images are studied. We present simulation results of gratings diffraction efficiencies, experimental observations of gratings and DOEs behaviour illuminated with a fiber laser beam. We demonstrate that the fiber laser, showing good beam quality, can be used with standard diffractive structures with interesting results.

Online detection of harmful exhaust gases is necessary for optimal engine control to reduce the polluting emissions of diesel cars. Optical detection methods in the UV-VIS range enable the simultaneous characterisation of various gases such as NO, NO₂ and SO₂. Additionally this technique is fast and has a low cross-sensitivity to other exhaust components. First results show the advantages for the optical approach compared with standard electrochemical gas sensors.

This paper describes two optical based sensors for the detection and quantification of vehicle exhaust pollutants. The first sensor consists of a single pass absorption cell. Broadband light from a deuterium/halogen source was transmitted through the cell from optical fibre and the resulting absorption is detected using a UV spectrometer which was also fibre coupled. The second approach includes an integrating sphere, which has been adapted for use as a multipass absorption cell. An ultraviolet LED was used as an emitter and a photodiode as the detector. Both were mounted directly on the sphere. The single pass absorption cell has been used to monitor nitric oxide, nitrogen dioxide and sulphur dioxide while the integrating sphere has been used to monitor nitrogen dioxide levels. Concentration levels of 10's of parts per million have been measured for each gas and sensor.

This paper discusses the development of an optical fibre sensor suitable for the detection of gas emissions from motor vehicles based on mid-infrared spectroscopy. Initial measurements are presented for carbon dioxide emissions from a petrol engine using low-cost mid-infrared components, and a practical detection system, which could be fitted to a vehicle, is outlined.

Pedestrian fatalities are around 15% of the traffic fatalities in Europe. A proposed EU regulation requires the automotive industry to develop technologies that will substantially decrease the risk for Vulnerable Road Users when hit by a vehicle. Automatic Brake Assist systems, activated by a suitable sensor, will reduce the speed of the vehicle before the impact, independent of any driver interaction. Long Wavelength Infrared technology is an ideal candidate for such sensors, but requires a significant cost reduction. The target necessary for automotive serial applications are well below the cost of systems available today. Uncooled bolometer arrays are the most mature technology for Long Wave Infrared with low-cost potential. Analyses show that sensor size and production yield along with vacuum packaging and the optical components are the main cost drivers. A project has been started to design a new Long Wave Infrared system with a ten times cost reduction potential, optimized for the pedestrian protection requirement. It will take advantage of the progress in Micro Electro-Mechanical Systems and Long Wave Infrared optics to keep the cost down. Deployable and pre-impact braking systems can become effective alternatives to passive impact protection systems solutions fulfilling the EU pedestrian protection regulation. Low-cost Long Wave Infrared sensors will be an important enabler to make such systems cost competitive, allowing high market penetration.

Thermopile pyrometer modules are the state of the art for contactless temperature measurement in automotive applications. Here sensors have to operate precisely in a challenging thermal environment. While the compensation of the steady state ambient temperature is a well known technique in thermopile radiation temperature sensors, transient thermal effects are still an issue. The change of the ambient temperature as well as temperature flow through the sensor can lead to substantial errors due to unwanted thermal gradients within the device. In the thermopile chip they leads to an error signal since the measurement principle is based on quantifying thermal gradients of the chip that result from the detected IR-radiation. Thermal gradients in the cap and between cap and thermopile chip lead to an exchange of heat radiation between thermopile chip and cap that is erroneously detected and thus also leads to errors. Different methods were developed that separately or in combination allow for a significant improvement of the accuracy and signal stability. The methods are based on the reduction of thermal gradients within the thermopile chip and the entire sensor device (isothermal, high thermal mass cap), reduction of radiation exchange between the sensor chip and the housing (low emissive inner cap surface) and prediction and software compensation of the error signal.

The design of an efficient LED package, with a high luminous flux, stable wavelength emission and long lifetime needs a good knowledge about the principles of light emitting diodes, thermal and thermomechanical design and the interaction of materials. The technology development under cost aspects is a general constraint. The following work will combine known aspects from different research fields with own developments to a complete design for an ultra high brightness LED package. Topics as material selection, thermal and electrical interconnections, as well as color stable wavelength conversion will be discussed.

An analysis is presented of the sources and levels of crosstalk between the two signals propagating in opposite directions on a bi-directional plastic fibre link. Contributions to crosstalk from limits on the directivity of a new POF directional coupler and Rayleigh backscattering from the POF fiber are considered individually. The measured directivity of the coupler is 37.3 dB, better than any previous POF directional coupler. It is shown both theoretically and experimentally that Rayleigh generated crosstalk decreases with the increasing fiber length and that the level reaches a limit value circa 28.5 dB (below the input fiber level) when fiber length exceeds 36.5 meters.

We are proposing a novel method to implement high resolution optical position sensors for automotive and other applications. Grating diffractive incremental encoders (both linear and rotation) are already becoming commodity products now, and include a read-out grating and a ruling grating [3]. We are implementing out high resolution incremental and/or absolute position encoders with a single diffractive substrate, replicated in mass in plastic. The diffractive structures are here much more complex than standard linear gratings. These new optical position sensors can achieve high absolute resolution without need of electronic interpolation, therefore being potentially very fast and accurate. Furthermore, due to the nature of these diffractive optical elements (surface relief elements), they are very cheaply replicated in mass by either polymers embossing or injection moulding.

Optical fiber are used in plenty of application fields. One of these is precise optical sensing. We present here the concept of an optical Sagnac fiber interferometer that could be used for rotation sensing in automobile. Actual developpement in optical sensing include integrated optics. We discuss in the end of this article the feasibility of an integrated optics Sagnac interferometer.

A night vision system must increase visibility in situations where only low beam headlights can be used today. As pedestrians and animals have the highest risk increase in night time traffic due to darkness, the ability of detecting those objects should be the main performance criteria, and the system must remain effective when facing the headlights of oncoming vehicles. Far infrared system has been shown to be superior to near infrared system in terms of pedestrian detection distance. Near infrared images were rated to have significantly higher visual clutter compared with far infrared images. Visual clutter has been shown to correlate with reduction in detection distance of pedestrians. Far infrared images are perceived as being more unusual and therefore more difficult to interpret, although the image appearance is likely related to the lower visual clutter. However, the main issue comparing the two technologies should be how well they solve the driver's problem with insufficient visibility under low beam conditions, especially of pedestrians and other vulnerable road users. With the addition of an automatic detection aid, a main issue will be whether the advantage of FIR systems will vanish given NIR systems with well performing automatic pedestrian detection functionality. The first night vision introductions did not generate the sales volumes initially expected. A renewed interest in night vision systems are however to be expected after the release of night vision systems by BMW, Mercedes and Honda, the latter with automatic pedestrian detection.

The Light Technology Institute conducted an investigation among more than 300 car drivers, 60 truck drivers and 40 bus drivers. We found out that more than 60 percent feel that the greatest problem in driving at night is glare. In theory, a car of today does not cause glare problems. However, in practice, most people feel glared. Consequently, technological improvements have to be made regarding the development of headlamps that will not glare. Another approach is to introduce more and better night vision systems to enhance drivers' sight with today's headlamps.

Efficiency considerations have direct implications on the performance of a projection headlamp and on its implementation into a car. Therefore, an attempt was made to work out a theoretical basis to gain a better understanding of the underlying parameter dependencies that determine the efficiency of a projection system. Designing a modern headlamp, it seems indispensable to use numerical algorithms to obtain the final design. The reason why this analytical study on the parameter dependence of the relative efficiency has been undertaken is that it provides some insight into the structure of the multidimensional solution space of this multi-parameter problem and gives a straightforward guideline to identify optimum solutions. Another motivation stems from the fact that understanding the influence of systems parameters is of key importance for the design of adaptive illumination systems. The method of analysis combines geometrical considerations, analytical ray tracing and calculus to find an expression for a system consisting of an open tri-axial ellipsoidal reflector and a projection lens. The new integral expression allows, for example, to study the influence of the transversal anisotropy of the tri-axial reflector on the relative efficiency of the system. In addition, the effect of mechanical boundary conditions imposed on the reflector of low symmetry and/or the lens can be considered in detail. From the theoretical point of view, it is advantageous that the integral expression, which has been found, is useful to elucidate the underlying scaling laws.

The dramatic increase of electronic components and devices in passenger cars tends to result in a further miniaturization of these components. In this context the chip on board technology of semiconductor devices and semiconductor light sources without extern housing and without extern optic devices gains importance. Not only the required space of further developed optoelectronic devices could be critical but also the consumption of electrical energy must be decreased. As this paper shows a direct encapsulation of Light emitting diodes (LEDs) by dint of an injection molding tool is possible. Forming the optical geometry to gain the required radiation pattern within this encapsulation process has been proofed to be feasible. In a first approach we investigated a two step encapsulation process but with the further development we ascertained a similar drop out rate for a single step encapsulation process. In particular with regard to the processing of temperature sensitive semiconductor devices specific knowledge on the thermal load is required for product life-time estimation. Therefore temperature measurement during the encapsulation process is a key point.

In the recent years LEDs became the standard light source for the dashboard, instrument panel and switches in automobiles. In the near future LEDs will bring ambient interior light functions into the vehicle. Advantages of the LEDs are a small installation space, low heat dissipation, the long lifetime and, with Multi-Color-LEDs, the possibility of color tunability. Ambient lighting of door surfaces, floor space and roof liner is beneficial, because it improves drivers orientation and thereby the driving safety. However the optimal parameters of color and brightness are not known yet. An investigation of the Light Technology Institute follows this question and presents within this framework, how the choice of the ambient lightings color and brightness affect drivers contrast vision.