2007 Issue 3 - Raytheon

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onTechnology Ultra Low-Power Flexible Electrophoretic Displays Whether it uses flashing LEDs or a 60-inch plasma TV, every electronic device needs a way to present information. Today, most interactive devices (including laptops, cell phones and PDAs) use a liquid crystal display (LCD) to display information. While LCDs have many advantages over their predecessor, cathode ray tubes, they still leave much to be desired for many applications — especially the dismounted soldier. LCDs require a power-hungry backlight, have poor outdoor viewing characteristics, and have a form factor that limits portability. With soldiers already heavily loaded with existing equipment, adding batteries to the load is not a popular option. On the contrary, electrophoretic displays (EPDs), sometimes called electronic paper, have enhanced readability and operate at up to 100X lower power levels. In addition, EPDs can be made in a flexible form factor, allowing for tighter integration with the soldier’s uniform. This article describes the technology behind EPDs and discusses why Raytheon is leading the integration of soldier applications in this industry. If you’ve ever used your cell phone or PDA in direct sunlight, you know an LCD’s readability limitations — poor contrast ratio in bright conditions. Since EPDs are reflective and operate without a backlight, they behave just like paper; that is, they maintain 18 2007 ISSUE 3 RAYTHEON TECHNOLOGY TODAY MATERIALS & STRUCTURES the same contrast ratio over all viewing conditions, including direct sunlight at 170degree viewing angle. It’s just like reading the newspaper. This is critical for the dismounted solder who often works outdoors. In addition to helping readability, removing the backlight also eliminates a large percentage of the display’s power usage. Furthermore, the “ink” used in EPDs is bistable, meaning that power can be completely removed from the system, and the display will retain its state. Power is only consumed when changing the display’s state. This allows systems to use far fewer batteries, and as such, removes unnecessary weight from the soldier. Electronic paper was first developed in the 1970s at Xerox’s Palo Alto Research Center, but was not widely commercialized until Joseph Jacobson, a professor in the MIT Media Lab, founded E Ink in 1997. Since then, E Ink has begun integration of their proprietary imaging film, or ink, into watches, cell phones, smart cards and large signs. E Ink’s imaging film utilizes millions of tiny microcapsules, each about 50µm in diameter, filled with electrically charged white and black pigments suspended in a clear fluid. The black pigment is negatively charged, while the white pigment is positively charged. Thus, when an electric field is applied across the microcapsules, the Courtesy of U.S. Army Natick Soldier Research Development and Engineering Center pigments separate and are forced against the top and bottom walls of the microcapsule. Depending on the polarity of the applied field, the viewer will see the display turn white or black. To render a pixilated image on an EPD, the microcapsules must be sandwiched between two electrodes. The top electrode is a uniformly charged, optically transparent, conducting material, and the bottom electrode (called the backplane) contains an array of electrodes to form the pixel array. Much like LCDs, EPDs can utilize thin film transistors (TFT) to form the active matrix of pixels. The backplane is then connected to display circuitry, which switches the “ink” on and off at specific pixels by applying the correct voltage patterns. To achieve a full color EPD, a color filter array (CFA) is placed above the microcapsules. The CFA typically consists of a regular pattern of three or four colors (one assigned to each pixel) spread across the surface of the display. For example, a 2x2 grid of red, green, blue and white pixels may be repeated across the entire surface of the CFA. To reproduce color, the driving circuitry must control each subpixel according to the desired color of the pixel. More than 4,000 colors are possible with this approach. YESTERDAY…TODAY…TOMORROW
There are currently limitations to the technology as it stands today. While lowresolution flexible displays presently exist, high-resolution flexible displays still represent a manufacturing challenge. For a high-resolution flexible EPD (>80ppi), a TFT backplane must be made on a flexible substrate, such as polymer film or thin steel. This is a significant challenge, and it will require continued research over the next few years from the industry. An additional challenge remaining with EPDs is to increase the update rate. Currently, the image update time ranges from 260ms (black and white mode) to 740ms (grayscale mode). To attain the maximum power advantage by utilizing bistability, it is actually desired that the average update rate be slow. For certain applications, such as electronic books, this is the exact intended use. Raytheon has partnered with E Ink and the Flexible Display Center (FDC) at Arizona State University to accelerate the road map of flexible display technology. We are leveraging commercial products from E Ink to produce militarized prototype units to be tested by the dismounted soldier. This promotes customer interest and helps identify the first generation market space for this new technology. To achieve true Network Centric Operations, we must extend the network down to the individual soldier. EPDs are a key enabling technology to achieve a userfriendly, ultra low-power network at this level. Raytheon’s expertise in communications systems and flexible displays enables potential MSI roles for future C2 and situational awareness systems. In addition, there are multiple opportunities for new applications, such as wearable displays and rollable, tileable large situation displays. Ben Howe bmhowe@raytheon.com Supporting Math and Science Education When you help a student master the Pythagorean theorem, you could be supporting a future engineer who will master nanotechnology. That’s why Raytheon created MathMovesUTM , a national initiative designed to show middle school students that they can master math, and that it will take them to lots of cool places. Raytheon is also proud to support MATHCOUNTS ® , which motivates more than 500,000 middle school students to sharpen their math skills each year. By working to improve our children’s proficiency in math and science today, we’re giving them what they need to improve our world tomorrow. www.MathMovesU.com © 2007 Raytheon Company. All rights reserved. “Customer Success Is Our Mission” is a registered trademark of Raytheon Company. MathMovesU is a trademark of Raytheon Company. MATHCOUNTS is a registered trademark of the MATHCOUNTS Foundation.
Page 1 and 2: Technology Today HIGHLIGHTING RAYTH
Page 3 and 4: Technology Today is published quart
Page 5 and 6: Raytheon is developing enterprise a
Page 7 and 8: Raytheon was awarded a $100 million
Page 9 and 10: ENGINEERING PROFILE Guy Germana Sen
Page 11 and 12: Leveraging Technology to Realize Se
Page 13 and 14: as separate services (or be replace
Page 15 and 16: LEADERS CORNER Dr. Peter Boland Vic
Page 17: onTechnology The Many Benefits of C
Page 21 and 22: Getting to Know Your Raytheon Certi
Page 23 and 24: The National Air and Space Museum
Page 25 and 26: Raytheon Technology Network Spring
Page 27 and 28: corporate technology goals for 2007
Page 29 and 30: Raytheon Acquires Percy Spencer’s
Page 31 and 32: CHINA, SOUTH KOREA JAMES FLORENCE P

2007 Issue 3 - Raytheon

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