Sunday, September 23, 2018

Corning's Secret Menu

Many fast food restaurants have “secret menus” and many fine restaurants also allow customers to “order off the menu” provided they have the ingredients. In most cases these secret menu items are things dreamed up by customers but grow so popular they either become well known “secret menu” items or actually make it on to the published menu. Optical fiber resulted from a request from British Telecom. When Steve Jobs first met with Corning’s chairman, Wendell Weeks, at Kuleto’s Restaurant in Burlingame California, Steve Jobs was there to order off the secret menu, Corning’s not Kuleto’s. Corning had previously made an extra hard chemically strengthened glass called ChemCor(R). It was used for, among other things, for the windshields for the Lunar Landers during the Apollo missions to the moon. Jobs needed ChemCor to mitigate scratching of Apple’s new iPHone. The reintroduced product was renamed Gorilla Glass(R).

Corning has been in operation for over 160 years and has maintained a large R&D function for over 150 of those years. During that time it has accumulated a huge secret menu. One of the latest items to make it back on the formal menu is Photo Structured Glass (PSG) or Photomachinable Glass. PSG is glass that can be precision etched after marking with UV light. It was developed by Corning just prior to WWII but was not patented immediately due to its use as a secret way to pass messages. When it was commercialized it eventually found use as a medium for micromachining, micromilling, microfabrication, and eventually as the substrate for microfluidics. PSG is the foundation of a precision forming process that can produce microchannels with absolutely vertical walls, precision apertures, and extremely complex shapes. Unlike laser etching of metal parts, the resulting PSG parts have the lubiricity and electrical resistance of a glass as well as the overall inertness and environmental stability of glass. Substitution for other materials and process can lead to increased productivity and increased yield.

The main product that PhotoCor(R) (the original name) was used for was for microfluidics. Schott Glass introduced its own version called Forturan(R) in the 1980's. With the growth of genetic sequencing, PSG has earned its way back on the menu and is available from Corning.

Contact: Berkeley Johnson at Corning +1.805.962.3333

Tuesday, February 3, 2015

Engineering vs. Physics

In technical developments, I was taught to think of problems in terms of one basic dichotomy, "Engineering Problems vs. Physics Problems." Engineering problems are things such as cost, having the right tools, or product design issues. These are problems that can be solved with time or with just working harder; things you basically know how to solve although the best solution may not be apparent. Physics problems are much harder. These are problems that say for the product to operate in the way envisioned, it must violate some law of physics or some fundamental property of the materials or system being employed. This is not to say that the problem is unsolvable but that some invention is required for the product to work but in a different way from what was initially envisioned.

Amazingly, inventors and whole organizations can labor away at physics problems for years and years as if it were some routine engineering issue they were tackling. One of the more famous of these was American Optical's efforts to invent optical fiber. American Optical worked on the problem for years before the Corning invented a fiber and a manufacturing process that actually worked. The Corning inventions being direct and very simple (as many great inventions are) it was easily copied by American Optical who went into manufacture using the Corning inventions claiming prior art. Of course law suits ensued. American Optical lost because Corning was able to demonstrate that 1) American Optical never understood the physics of the problem they were trying to solve and 2) As to their prior art, if they had worked in that direction for a 1000 years, they would never have produced a working fiber because again, they didn't understand the nature of the problem they were trying to solve.

This long intro is a preface to discussion of Apple's recent decision to spend $2 Billion to convert the GTAT facility into a data center. Clearly Apple is giving up on sapphire, otherwise GTAT or some restructured version of it might be useful going forward. This would tend to show that Apple ran into a Physics Problem in converting from glass to sapphire, not: cost or yield issues, design issues, tooling or such. Sapphire actually had to physics issues fundamental to the nature of the material.

As described in "Big Surprise," although sapphire was harder and more scratch resistant than glass, with that hardness came brittleness. Secondly, and more importantly, sapphire has a higher index of refraction meaning that screens made with a sapphire overlay would have much higher surface reflections than glass. With LCDs having marginal performance outdoors anyway, the surface reflection issue made the material a "non-starter". Apple did file some patents that Applied the Gorilla Glass process to sapphire in an effort to make it tougher and patents concerning overlays to address the surface reflection issue. However, there is a Second Law of Thermodynamics problem in that secondary systems to correct system inefficiencies inevitably can not correct all of them. This is the reason why you can not build an auto engine that is 100% efficient... or anywhere near 100%. In the case of optics, secondary corrections (additional layers) inevitably create their own surface reflections, decrease optical throughput, add expense, cut yield, and otherwise introduce new inefficiencies that were not present in the original system. Frequently its like drilling a hole in the bottom of a sinking boat to let the water run out.

So, after a billion dollars of investment to produce sapphire for iPhone screens, the facility is being converted into a data center. I'm reminded of the ending of "Raiders of the Lost Ark," after such prodigious efforts to find the Ark it gets nailed up in a box, placed in government storage and lost again. Some of the sapphire making furnaces will no doubt find new homes. But placing so many at once, many might wind up being nailed up in boxes, mute testament to the years long hubbub over sapphire covered iPhones.

Tuesday, January 6, 2015

More on Display-Centric Movies

I had done a couple of posts on movies where display technology was central to the movie plot (here and here), naming a top ten. Of the ten, there were many other movies that I cold have named e.g. Star Wars, Star Trek, The Matrix, Total Recall, The Avengers); but for better or worse I chose the ten that I did. I recently saw a YouTube posting that I may have omitted a big one... 2001 A Space Odyssey.

The premise of the YouTube video is that the monolith (the 1 x 4 x 9 object that appears at the dawn of human intelligence) is actually a widescreen TV set on end. Although videos are not project on the monolith, it serves as a teaching tool for proto-humans early on in the movie, a means of conveying ideas. Later, when a duplicate appears orbiting Jupiter, it appears as a doorway to other worlds and it eventually transforms into the ultimate immersive display. In function, it exhibits the best of what TV is supposed to do. In physical form, the 4:9 aspect ratio (2.25 width to height) falls beyond the old 1.85 US widescreen standard and just short of the current 2.33 standard. The thickness is greater than what you would currently get in a TV but perhaps it has really good built in sound.

On a tangential subject, over the holidays I saw "The Hobbit, the Battle of the 5 Armies" in 3D. Thankfully, filmmakers have gotten out of the habit of throwing things out of the screen at you with their new-found toy in 3D and the use of 3D was quite acceptable. However, the thing that 3D was really supposed to bring, increased realism was very much lacking in the presentation. The digital projection was sharp and crisp as it is supposed to be, but it gave the overall effect of artificiality. Rather than being as looking through a window, the digital projection makes it painfully obvious the image is a projection. In a recent edition of "The Economist" director Quentin Tarantino describes digital cinema as "The death of Cinema as we know it". The Economist article goes on to state, "Digital projectors cannot match the sheer detail of a pristine 35mm print, nor its rich contrast between the deepest shadows and brightest highlights." However, for me, it was not the lack of detail but the digitized edges (not quite jaggies)that gave a fake feel to the image. Seemingly, this is something that could be corrected with software, however the function of most image enhancement software is edge sharpening rather than edge blurring. Perhaps the role of image post processing in cinema should be re-thought. In any case, as in my 10th selection for display centric movies, "Here's to Film".

Wednesday, November 26, 2014

OLEDS and Why Your Old CRT TV still Works

Two stories about TV, not directly about OLED, that I will tie together down below. This note is about OLEDs. Although you can not buy a LCD TV that was made in the US, the active matrix LCD was actually invented in the US, in Pittsburgh by Westinghouse. Westinghouse was a prominent TV brand that was developing new technology. Westinghouse did not survive in the TV business long enough to capitalize on their invention because they had a problem at their factory. It seems a worker replaced a steel mesh filter in their water reclaim system with a copper coated steel mesh filter. That put just enough copper into the wash water and just enough wash water residue was left on the TV screen to serve as a phosphor poison. The TV tubes that the Westinghouse factory was making would go dark after about 6 months of use. The resultant recall of half a year’s production put Westinghouse out of the TV business. Parts per billion of copper put them out of business.

Another major brand of TV in those times was General Electric (GE). Although GE made glass for things such as light bulbs and such, GE bought their glass for CRT tubes from others. In addition to making glass, GE had an array of materials technologies including silicones and polycarbonate. At one point, in order to put downward pressure on glass prices, GE threatened to develop a polycarbonate CRT bulb. The glassmakers looked at the threat and determined that although such a product was possible and did have some advantages relative to glass, the product would only last about a year before there was enough inward migration of atmospheric gas to render the polycarbonate CRT non-functional.

The point of both stories is that emissive technologies tend to be sensitive to the most minute amount of contaminants. That is why some of the companies developing OLED technology concentrate on an ultra-clean manufacturing environment. It is also why the other key to OLED’s future is hermaticity. In a CRT, glass provided an absolute hermetic environment. The CRT was made in a clean environment, the inside of the tube, where the phosphors were, was maintained in high vacuum. Further a sacrificial barium “getter” was deposited on the inside of the tube to bind any stray oxygen that was left over from manufacture.

So, the phosphors did their thing in an absolutely pristine environment that was maintained as long as the tube continued to hold its vacuum, which is tantamount to forever for a consumer product. In terms of product chemistry, the environment virtually eliminated any alternative pathways that could be formed between the phosphor in its elevated state and when it drops back down to its base state by emitting a photon. The industry employed other tricks, such as moving to higher and higher voltage phosphors. This brought the product to the point where the phosphor aging was no longer the primary aging limitation but metallization of the glass from decades of electron bombardment.

The high voltage architecture may have some relevance to OLED design as well. But certainly, cleanliness and hermaticity are the key to making OLED technology work.