Electronic Design

Displays And Capacitors Leap Forward

There were some rich developments in components in 2007, particularly in innovative display technologies. Novaled, Immersion, and Clairvoyante all reported key advances. And necessary though taken for granted, capacitors also saw a noteworthy development, thanks to Electronic Concepts.

Novaled has extended the life of white organic LEDs (OLEDs), addressing a primary concern surrounding their use. As a result of proprietary PIN OLED technology and materials, the company reports an efficiency of 35 lm/W and a lifetime of 100,000 hours at a brightness of 1000 cd/m2. At a brightness level of 4000 cd/m2, white OLED efficiency is 31 lm/W with no significant changes in color or color rendering index (CRI) value.

The component exhibits CIE color coordinates of x/y = 0,43/0,44 with a CRI of 90. It also features a stacked setup with blue fluorescent and red/green phosphorescent emitter materials, described as a hybrid approach. Proprietary materials make up the stacking and transport layers. Plus, the device includes a standard out-coupling enhancement film.

Delivering a taste of virtual reality, Immersion’s TouchSense technology makes graphic buttons on a touchscreen feel like their mechanical ancestors. The tactile-generation technology, consisting of an interface and software, feeds back vibrations at varying frequencies, intensities, durations, and wave shapes to the touchscreen. This gives users the impression they are pushing buttons, toggling switches, and moving levers. These vibrations are synchronizeable with audio to further enhance the experience.

TouchSense is available in two versions: one for larger systems with touchscreen sizes from 2 in. to more than 19 in., and TouchSense Mobile supporting touchscreen sizes up to 15 cm diagonal (Fig. 1 and 2). In addition to opening a range of new consumer applications for touchscreens—i.e., cell phones, games, and media players—the technology has several essential benefits. As a tactile feel ensures an action occurs, the advantages are obvious for visually impaired users as well as in medical and industrial environments where users may need to wear gloves.

Also chipping away at the barriers to OLED usage, performance, and manufacturing concerns, PenTile RGB subpixel rendering technology from Clairvoyante opens the doors for the display market’s first high-resolution activematrix (AM) display panels using OLEDs. One of the challenges for such displays is getting the resolution beyond qVGA.

Higher resolutions require higher pixel counts, which require higher current levels. Higher current, in turn, significantly lowers the life expectancy of OLEDs. PenTile technology can deliver VGA resolution with a third fewer pixels than current LCD technologies, resulting in lower current and longer display life. On the manufacturing side, PenTile significantly reduces the number of transistors on the backplane, translating into higher backplane yields and even lower power consumption.

The first fruits of this technology will take the form of a handheld wVGA (480 by 800) OLED panel from Samsung SDI for handheld Web browser, GPS, and other portable video applications. Set for sampling during the first quarter of 2008, the display provides a diagonal viewing area of 3 in. and specifies a luminance of 200 cd/m2, a contrast ratio of 10,000:1, and an NTSC color gamut of 100% while consuming 400 mW.

Electronic Concepts’ Fuseac technology protects metallized film capacitors from failures due to overheating in ac applications. It performs like a thermal fuse, as it disconnects the capacitor from the circuit when it reaches a particular temperature.

The technology also can preset a critical temperature and pinpoint hot spots on the capacitor. In addition to providing reliable protection in system, Fuseac accounts for the self-healing properties of metallized film capacitors. By disconnecting the capacitor before healing is required, it eliminates excessive healings, which degrade the component over time and reduce its functional life.

The company’s 5MPF series of polypropylene film capacitors puts Fuseac to work (Fig. 3). These caps offer voltage ratings of 300, 600, and 900 V ac and capacitance values from 10 to 250 µF with an operating temperature range of –40°C to 85°C. Other features include inverter output filtering for Wye and Delta circuits.

TAGS: Components
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