A year ago, Corning published a promotional video, “A Day Made of Glass… Made possible by Corning” that provide an intriguing peek into some of the technologies the company is considering—and how it may affect our lifestyles. It proved to be a popular video, racking up well over 17 million views as of today.

As those of us old enough to remember Walt Disney’s movies about the future of communities, transportation and space, these visionary presentations are more informed guesswork than prophecy. Sometimes (most times?) these ideas just don’t work out for a number of reasons, but the exercise of compiling and publishing these visions helps bring excitement and motivation, especially to young people contemplating careers in science and engineering.

However, smart tech-oriented companies tend to be cautious about sharing their “visions” with the public (Steve Jobs was and Apple still is among those at the most secretive end of the spectrum) because they are both concerned about tipping their hand to competitors and, well, being embarrassed by being wrong about the future.

Corning, however, seems to be closer to the other end of the spectrum and has clearly decided that there is value in teasing the public with how high-tech glass products may disrupt a lot of technologies in our future. Now today, nearly on the anniversary of its first “A Day Made of Glass” video, the company has published an update,  ”A Day Made of Glass, Part 2″ that fleshes out more of Corning’s vision and also incorporates some of the market trends over the last year, such as the huge success of the iPad.

Some of the concepts illustrated in the new video include durable, multitouch screens; colossal- and large-scale edge-to-edge displays; ubiquitous electrochromic windows; entire dashboard surfaces made of soft, flexible glass displays; lightweight auto and sunroof glass; designer-friendly photovoltaic units; antimicrobial glass services for medical applications; and even advances in glass fiber optics.

Corning admits that a lot of these products aren’t right around the corner and acknowledges that there is still a lot of RD&D work that is needed to address existing problems with scalability and price.

To be clear, Corning is smart enough not to reveal all of its product and technology bets in this video. Furthermore, the Apple/Gorilla Glass story underlines how even Corning and other top-tier companies cannot always anticipate what external disruptions of the marketplace will rock their corporate world. Nevertheless, ADMOG Part 2 is an fascinating vision and I predict the number of views in the next year will easily exceed the 17 million of Part 1.

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Band structure of rutile SnO₂, illustrating free-carrier absorption. Visible light does not carry enough energy to excite carriers across the band gap (a) or to excite free carriers directly to the next conduction-band states (b). However, additional momentum provided by a phonon enables indirect free-carrier absorption (c) for any visible or infrared wavelength. States in the energy range of the visible spectrum are indicated. Credit: Peelaers et al.; Applied Physics Letters.

Transparency versus conductivity: The tug between those properties is often on the mind of those who engineer the components of optoelectronic devices, such as photovoltaic cells, photodetectors and LEDs. For example, contact materials for PV cells ideally would not absorb much light in the solar spectrum. Otherwise, efficiency gets reduced. Conductivity can be enhanced through doping, but that can affect transparency; conversely, optimal transparency can decrease conductivity.

Where’s the sweet spot? To begin answering that question, researchers in the Computational Materials Group at the University of California, Santa Barbara wanted to wrap their brains around the specific mechanisms for the absorption of light in simple transparent conducting oxide. Working completely from first principles and focusing on the mechanisms of free-carrier absorption for a widely used TCO material, n-type tin dioxide, they were able to predict the limits on optical transparency of SnO₂.

According to a UCSB press release, the researchers explain that SnO₂ works well as a conducting oxide because it only weakly absorbs visible light. The wide band gaps of transparent conducting oxides prevent absorption of visible light by excitation of electrons while dopant atoms provide additional electrons in the conduction band that enable electrical conductivity.

However, dopant-provided free electrons can also absorb light by being excited to higher conduction-band states. Thus, the transparency of SnO₂ declined when moving to other wavelength regions. The UCSB group reports that absorption was five-times stronger for ultraviolet light and 20-times stronger for the infrared light. Thus, SnO₂ is not optimal for devices that depend on the ultraviolet and infrared light, such as those used in some telecommunications applications.

In the release, Hartwin Peelaers, a postdoctoral researcher and the lead author of a paper published in Applied Physics Letters (doi:10.1063/1.3671162), is quoted as saying, ”Direct absorption of visible light cannot occur in [SnO₂] because the next available electron level is too high in energy. But we found that more complex absorption mechanisms, which also involve lattice vibrations, can be remarkably strong.”

Chris Van de Walle, a professor in the UCSB Materials Department and head of the research group, notes, ”Every bit of light that gets absorbed reduces the efficiency of a solar cell or LED. Understanding what causes the absorption is essential for engineering improved materials to be used in more efficient devices.”

Van de Walle’s Computational Materials Group explores semiconducting binary oxides, nitride semiconductors, novel channel materials and dielectrics, materials for quantum computing, photochemical hydrogen generation and metallic nanoparticles.

The UCSB group’s computational methods work and its investigations into TCOs — part of the school’s efforts as a Energy Frontier Research Center — is expected to lead to significant improvements of the energy efficiency of optoelectronic devices. Their work is also supported by the Belgian–American Educational Foundation, and by the UCSB Materials Research Laboratory, one of the NSF’s Materials Research Science and Engineering Centers.

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Artist’s rendering of mirror arrangement for Giant Magellan Telescope in Chile. Credit: GMT.

“Mirror, mirror on the wall/Who’s the best mirror maker of them all?”

In the story of Snow White, the magic mirror is an important supporting character. It sees into places its interrogator cannot and reports back on the who, what and where and shows the action. To create the fantastical mirror, Disney used a talented team of storywriters and celluloid artists.

Similarly, astronomers look out from observatories into places that are inaccessible to humankind, in part because our lifespans are too short. To build the instruments that allow them to do so, they turn to teams of specialists to craft the mirrors that are amazing in their own right. Among the best of the mirror makers is the team at the University of Arizona’s Steward Observatory Mirror Laboratory in Tucson.

Last week the lab cast the second of seven massive glass mirrors that will be shipped to Chile for installation in the Giant Magellan Telescope. When completed, GMT will be able to acquire images 10-times sharper than the Hubble Space Telescope. The six outer mirrors are off-axis paraboloids, which makes them “the greatest optics challenge ever undertaken in astronomical optics by a large factor,” according to Roger Engel in a press release. Engel is the director of the SOML.

The 8.4-meter-diameter (about 27 feet) mirrors are cast from 21 tons of borosilicate glass provided by the Ohara Corp. Glass chunks weighing 4-5 kilograms are inspected and carefully layed out over a ceramic mold.The glass is melted at 1,165°C (at which point the glass has a honey-like viscosity) in a furnace that rotates at about 4 rpm. (See the spinning furnace in the video.) The spinning helps form the parabolic shape and reduces the amount of finishing needed later. According to a brochure (pdf) from the SOML, the furnace will spin rapidly for four or five days, and then at a much slower rate as the mirror goes through a three-month-long controlled cooling.

Last week’s melting and casting process of the second mirror took about 22 hours and it is now in the lengthy cooling phase. After removal from the furnace, the mirror undergoes a rough grinding step and is polished to a finish that is within 25 nanometer of specifications.

The backs of the mirrors are cast in a honeycomb configuration to reduce their weight, and more importantly, to allow the mirrors to thermally equilibrate quickly. Temperature changes on the mountaintop are rapid and can be fairly large, but the borosilicate glass has a low coefficient of thermal expansion, which allows it to remain stable despite temperature changes.

The facility expects to cast one mirror per year to complete the project. Each mirror will be shipped to Chile after its finishing is completed.

A lot of space is needed to make castings this large and to do the post-processing, and one might wonder where a large, urban university found space for the facility. Under the football field!

The SOML brochure lists the mirrors made by the SOML since 1985. The university has other mirror fabrication projects underway. A recent Eureka Alert press release describes a multi-million dollar project to polish a 4.2-meter-wide mirror for the Advanced Technology Solar Telescope in Hawaii. The mirror blank is being made by Schott in Mainz, Germany.

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I’ve been following the news coverage of the annual Consumer Electronic Show held last week in Las Vegas, and it appears that a lot of writers were underwhelmed by what they saw. Some items, such as large-format OLED television screens and a slew of “smart” TVs, turned heads, but few observers claim to see any huge breakout products.

However, there was one event display that commentators consistently mentioned in positive tones: Corning’s booth where it showcased its glass technologies. In other words, one of the stars of the CES show wasn’t really a consumer product but is enabling technologies in the engineered glass field.

Importantly, Corning used the CES to do a public rollout of what it calls Gorilla Glass 2. From the Corning news release:

Corning Gorilla Glass 2 enables up to a 20 percent reduction in glass thickness, while maintaining the industry-leading damage resistance, toughness, and scratch resistance customers have come to expect from the world’s most widely deployed cover glass. The thinner Gorilla Glass 2 enables slimmer and sleeker devices, brighter images, and greater touch sensitivity. These benefits can provide electronics manufacturers with superior design flexibility as they address consumer demand for increasingly high-performing, touch-sensitive, and durable mobile devices.

James R. Steiner, senior vice president and general manager, Corning Specialty Materials, went on to say that

“[W]e designed this new glass to enable meaningful reduction in thickness without sacrificing the outstanding glass performance for which Gorilla Glass has become highly recognized. This glass, along with Windows operating system innovations from Microsoft, will help deliver exceptional beauty, performance, and toughness for new Windows PCs. You will see this early this year with Windows-based PCs which we expect to be the first in-market laptops designed to leverage the performance of our new second-generation glass.”

Corning also says that product qualification and design implementation for GG2 is underway with various customers, and a number of products containing GG2 are expected “during the coming months.”

GG is pretty ubiquitous, and the release claims that it is “the most widely deployed cover glass, used by more than 30 major brands and designed into more than 575 product models, spanning more than 500 million units worldwide. As one of the company’s fastest growing businesses, Corning Gorilla Glass is expected to reach more than $700 million in 2011 sales, nearly triple 2010 results.”

It’s probably not a coincidence, but Corning posted several new videos during the CES. I had hoped to provide a video specifically about GG2, and one was/is apparently in the works. I received a notice that a new video on GG2 had been posted on YouTube, but by the time I got around to try to take a look at it, it had been taken down by Corning. So, instead of a GG2 video, I am using a new video featuring Peter L. Bocko, Corning Glass Technologies’ CTO, who explains how the company foresees the market and demand for thin glass applications. Some of the new videos are:

• Corning sights & sounds at CES 2012
• Bocko commentary: A thinner display industry
• The fusion process: At the core of Corning’s glass innovations
• Corning Gorilla Glass for seamless, elegant design
• Corning’s ultra-slim flexible glass for roll-to-roll processing

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High clarity and concentricity are necessary features of aluminum oxynitride multimode seeker domes being developed for the Joint Air-to-Ground Missile. Credit: Surmet.

The business end of a missile is not the exploding part. Rather, it’s the guidance system that gets the missile to its target, or at least that’s what the guys who make the front end of the missile will tell you.

A critical piece of the guidance system is the dome on the leading tip of the missile. Multimode seeker domes are passive components (they don’t “do” anything), but they must meet stringent property and tolerance requirements. Multimode seeker domes are so named because they are optically transparent in the laser, IR and RF wavelength ranges.

There is significant interest in these domes because the Army and Navy have been developing a new weapon, the Joint Air-to-Ground Missile. In particular, aluminum oxynitride or spinel are candidate materials for JAGM dome systems.

The JAGM is being developed to replace the Hellfire, Javelin and TOW missiles according to an Aviation Week Aerospace Daily and Defense Report story. The military is designing the new missiles for air launch from various fixed-wing or rotary-wing aircraft mounts—six platforms in total.

Lockheed Martin and Raytheon-Boeing have been competing for the JAGM engineering and manufacturing development contract. An InsideDefense.com story reports that the Pentagon was planning to spend $1.7 billion for development and $6.5 billion to procure 20,000 missiles for the Army and 15,000 for the Navy/Marine Corps.

But, back in September, just when DOD was getting ready to decide which company would get the nod, the Army and Navy recommended terminating the program, apparently in response to budget constraints forced by the August debt ceiling agreement. Details are vague, but it looks like the JAGM program may have been downsized to an extended R&D program. At the very least, the Army is still awarding SBIR contracts, including one recently to Surmet of Burlington, Mass. to develop cost-effective multimode seeker domes.

According to Surmet chief technology officer, Lee Goldman, fabrication of domes is very costly because of the combined demands for very high optical clarity, homogeneous index of refraction and tight tolerance specifications.

Domes are made from powders pressed into net shape and fired. After firing, the domes are 100% dense and optically transparent, but the surfaces are rough, like ground glass. Surfaces are ground and polished to a mirror smooth finish. Also, the finished domes must have a high degree of concentricity to prevent distortion of the transmitted wavefronts.

“It is common practice in the industry, because of the tight tolerances, to do an inspection polish,” according to Goldman to evaluate the optical quality. Between the hardness of aluminum oxynitride or spinel and the extremely tight dimensional tolerances, inspection polishing adds significant cost to the domes.

Not surprisingly, the military is interested in know whether any cost-savings is possible. Thus, the goal of the Army SBIR is to develop a nondestructive evaluation method to assess the optical quality of the domes prior to inspection polishing. By doing so, the company believes it can reduce the cost of domes by up to 20%. There is a lot of potential savings because if the JAGM goes into production, 30,000-40,000 domes would be needed. With the NDE method, a representative sampling of domes could be testing quickly and cost-effectively.

Surmet has been working with the Army since 2002 on a variety of transparent ceramics for military applications.

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