Efficient out-coupling light extraction and optical beam shaping have been combined to form an integrated, flexible illuminator that is based on organic light-emitting diodes (OLEDs). Spherical refractive microlenses were replicated by a cost-effective UV-casting technique onto a plastic foil to achieve the customized Gaussian distribution of the electroluminescence of an OLED pixel (50μm) matrix. The fabricated optical device, namely a ceiling light illuminator, shows an improvement of 70% in the out-coupled emission measured in the far field. The result corresponds to the theoretical prediction for isotropic emitting sources.

Electrostatic film based light modulators are discussed. Electrostatically driven microstructures can close or open parts of a transparent substrate modulating the incident light. The surface of the microstructures can be used as shutter or as mirror or simultaneously in both functions. Photolithography and thin film technologies have been used to build microshutter-micromirror arrays. Refractive, diffractive and micro-optical systems based on glasses or polymers can be combined with the presented arrays in integrated solutions. Finally a display integrated in an automotive instrument cluster is discussed. IntroductionThe present instrument cluster is an agglomerate of different components, developed by different technologies usually located in different plants. The instrument panel has an on board electronics, bulky mechanical parts (stepper motors), independent lamps and/or complex wave guides that transmit light to the visible surface, small liquid crystal displays. Many cables link the instruments to the external world: speedometer, thermocouples, etc. The Fig. 1 is an exploded view of an instrument cluster.The evolution of the automotive instrument cluster is driven by two main needs: improved functionality for a user friendly presentation of the information and manufacturing process simplification. The enabling technology consists in a new approach on microsystems fabrication.On Fig. 2 we show a sketch of the proposed instrument cluster designed as a flat structure integrating flat panel displays, advanced pointer movements and electronic components. The connections from the external world flow on a bus to a microprocessor which drives the flat electrostatic pointer movers, the displays and the light sources. Compatible technologies are under study at CRF to develop the display (made by electrostatic microshutters) pointer movers (made by flat electrostatic films) and the light wave guides and sources. The following figure shows a possible integration of the technologies mentioned above in a compact instrument cluster design.The electrostatic pointer actuators have been presented in a previous work [1]. In the present paper we will focus on the microshutter-based displays. Automotive displaysThe most widely used technology in automotive display is liquid crystal display technology (LCD). A coarse classification can be done dividing LCD displays in two main categories: passive matrix (PMLCD) and active matrix (AMLCD). The first class find application in small size displays mounted in the instrument cluster. The main problem with enlarging PMLCD is the degraded contrast and viewing angle as more and more lines are multiplexed. AMLCD are often used for large area screens as for instance for navigational displays but a wider application is limited by cost.Other technologies are under study for automotive flat panel displays: of particular interest is the light emitting polymer (LEP or OLED) technology but at the moment because of cost, lifetime, temperature range the materials are not suitable for an automotive...

Optical coupling of flexible microstructured organic light sources for automotive applications Melpignano, P.; Sinesi, S.; Rotaris, G.; Antonipieri, M.; Cicoira, F.; Loi, Maria; Muccini, M.; Zamboni, R.; Gale, M.T.; Westenhöfer, S. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. AbstractIn this paper, we report on modelling and processing of customised optical patterns coupled with microstructured large area organic light emitting device (OLED) sources for automotive lighting. Different approaches for the optical control of the light emitted from an OLED are discussed and compared with the aim to fulfil automotive specifications for the following devices: side-marker, ceiling light and glove-box illuminators.

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