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EETE JUNE 2013

MEMS-based micro mirror laser projector can be integrated into cell phones By Julien Happich For years, Fraunhofer IPMS has been working on scanning mirrors for light deflection in one and two dimensions. Alongside resonant scanners with constant sinusoidal movement, a quasi-static variation has also been available for a while, which serves to make Linear movement or static orientation in a specified position possible. Both types make compact laser projection systems possible in practice. These could be used as pico-projector components to be integrated into smart phones, supporting projections at the size of a TV screen, even at a short projection distance. Fraunhofer IPMS now concentrates on the “laser beam steering” principle for image generation. Here, a brightness controlled laser beam (e.g. three, in red, green and blue, for full color display) is directed by a single miniaturized scanning mirror over the projection surface fast enough to generate an image which appears cohesive to the human eye. The scanning mirrors typically have a diameter of about one millimeter and are manufactured from mono-crystalline silicon wafers using established processes in cost-effective, large batches in the MEMs clean room at Fraunhofer IPMS. Fraunhofer IPMS utilizes an electrostatic actuator with comb shaped electrodes for the necessary movement of the scanning mirrors. It was easy to make one and two dimensional scanners with conventional planar structures (i.e. mirror, outer frame and actuator combs lay on one plane). However, in this case, the resonating frequency is set, and changing the horizontal frequency, for example, is hardly possible. For another thing, the high scan frequencies bound to the double resonant principle are contrary to the trend toward increasing pixel counts in the projected image – right up to full HD. These disadvantages are overcome with the new quasi-static scanner concept from Fraunhofer IPMS, called LinScan. It requires one subsequent micro-assembly step, along with a small modification to the mechanical design to permanently tilt the actuator combs toward each other. The Institute was able to show that the combination of a resonant actuator on the quick horizontal axis and LinScan on the slower vertical axis is possible for a two-dimensional scanner like those necessary for pico-projectors. The laser beam can now make targeted jumps from line to line according to an externally configured frequency. This could yield pico-projectors with a SVGA resolution (800 × 600) and higher. As no projection optics are necessary, the result is always a sharp image. Redux Labs spins out from HiWave to develop new haptics and embedded audio By Julien Happich Led by HiWave’s former CEO and CTO, James Lewis and Chris Travis, start-up Redux Labs has been spun out to advance its Surface Sensation technology for third generation haptic and embedded audio technology. The company will deliver a range of haptic/ touch and audio transducers, electronic control modules and chipsets, evaluation platforms and bespoke system development for multiple market sectors. Redux’s Surface Sensation use patented techniques that precisely control bending subsonic audio waves across a screen to deliver 3D Haptics functionality. The technology’s configurability allows OEM product developers to accurately mimic the tactile and acoustic sensations of real-world user inputs such as sliders or a specific button presses on a flat panel such as a display. For example, users could discern the separate keys on a tablet keyboard, or drivers could locate and operate touch panel switches in vehicles without being visually distracted. These haptic effects are localised to the point of touch enabling an effective multi-touch environment where the tactile sensation is only felt by the finger pressing the key. The same transducers can also cover the audible spectrum to deliver audio cues, messages and alerts from the surface being touched. By applying these same techniques to audible frequencies, Redux has also developed products that turn a screen or panel into a high quality, forward facing loud speaker, delivering crisp and clear full-range audio directly to the listener. Surface Sensation is being targeted at flatscreen TVs, laptops, phones and tablet PCs, in which it is expected to replace internal micro speakers. The technology also delivers top quality audio and compelling haptics from other material surfaces including metal, plastics and composites. James Lewis, Redux CEO said: “Redux will focus on advancing and commercialising haptic and audio solutions, and to develop ground breaking technology that redefines the user experience in an increasingly touch-display oriented world.” 14 Electronic Engineering Times Europe June 2013 www.electronics-eetimes.com


EETE JUNE 2013
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