OLEDs and Swords

At my undergraduate college, one of the first things you are given to do in materials science lab is to make a small version of a samurai sword. Though the student body is certainly smart enough and they understand the principles, no one ever makes one that works, at least not to my knowledge. Success depends on getting the edge of the sword to follow the water quenching curve on the diagram while the time-temperature-transformation profile of the back of the sword more resembles the air cooling curve. Of course, the entire sword has to be water quenched at once. There is a story about a samurai sword maker that cut off the hand o his apprentice when the apprentice stuck his hand in the quench water to see what temperature it was; the water temperature was a secret that the master was not ready to reveal. The diagram above is referred to as a Time-Temperature-Tansformation (TTT) curve.

The entire process is very dynamic and analysis of the end product does not necessarily tell you what went on. The problem with a student sitting down and figuring this all out is that there are multiple variables and the entire process is very non-linear; the difference between being very close and being a million mils away is not always apparent. Sometimes it does not matter how smart you are, you have to have the right recipe. That is why a number of companies have sprung up in silicon valley that offer a process for testing multiple micro-samples at once, to speed up the process of finding the right recipe. This differs substantially from a normal product development where all of the sub-components can be tested separately. A valley VC that specializes in materials based companies once told me that he never actually invests in a company that has yet to complete their materials development. This is in part, why there are so few technical glass companies in the world. A lot depends on their experience and catalog of recipes (glass chemistry, furnace chemistry, heat treating, etc.) that they have built up over time. Sometimes tramp chemical elements in the parts per billion range can have a dramatic effect on the product outcome. As semi-conductor makers are aware, softly whispering the word alkali in the fab can put enough sodium in the product to kill production. It was a parts per billion chemistry issue (with a phosphor poison) that originally put Westinghouse, the inventor of the active matrix LCD, out of the TV business.

OLED process development has exactly the same issues.

Glass can be Hard for Digital Signage

Tutorial: Samurai Swords

Many crystalline structures actually get stronger under compression rather than weaker. A samurai sword is actually made from a straight piece of metal. It is the heat treating that causes the distinctive curvature and it is the heat treating that is responsible for the incredible sharpness. Iron forms different crystal structures at different temperatures and, like water, forming a new crystal structure at a lower temperature sometimes mean a volumetric expansion rather than contraction as in water to ice. The samurai sword heat treating process involves freezing in one crystal structure on the cutting edge of the blade while the body of the sword first contracts (forming the curvature) then goes through a final transition where it wants to expand. This leaves the edge under permanent compression and enables the edge to be polished to incredible levels of sharpness. Even though the process is centuries old, the metallurgy was not understood until the 1970s as nothing is at equilibrium. The image above is from the movie “Kill Bill” which provides ample demonstration of just how sharp samurai swords can be.

This principle of having the surface under compression from the internal structure is also used in glass. Correlle dinner ware is made from two separate glasses, a high expansion inner glass and a lower expansion outer glass. After the plates are formed from molten glass, the inner glass wants to contract more than the outer glass leaving the outer glass under compression. In chemically strengthened glass the outer layer compression is accomplished by substituting some of the atoms in the surface layer with atoms of a larger ionic diameter. Stuffing in these larger atoms leaves into the glass lattice leaves the surface under compression. In tempered glass, the compressive layer is due to freezing in an expanded, high temperature structure on the outside, while the interior cools more slowly and wants to contract.

Just on its own, glass can be pretty hard. Making it thicker makes it more rigid and less likely to break. The extra thickness can be either a monolithic structure or a laminate. It can also be over coated with materials that are even harder. Finally, for many applications, you can use a transparent plastic. Each approach has pluses and minuses.

Until now, glass has been the only material used in mainstream high information content displays. The displays themselves are going into different environments and designers of both digital signage and mobile devices (solar as well) are having to comprehend issues that they have never had to deal with before. This posting delves into some of these issues.

Coverglass Choices
Chemically strengthened glass can be made ultra-thin and is most commonly used on mobile devices where thinness is at a premium. However, the forming processes for very thin glass are limited and the ion exchange process to do the chemical strengthening is slow and therefore expensive. Also, the chemical strengthening must be done after cutting the pieces to size, further adding to the expense. (An earlier version of this post inadvertently stated the opposite. However the point is that the processing must be dome with individual parts rather than a motherglass, adding to the expense.) A Correlle-like structure could be tried but if you have ever owned Correlle, you may be aware that although the bi-glass structure works well, it does not work particularly well on the edges or any corners. Also, when the glass does break, due to the stored energy of the purpose built-in stress, it tends to shatter. (A well known book on WWII, concerns the Japanese defeat at Midway, “Shattered Sword”. The title of the book refers to the tendency of a well made samurai swords to shatter rather than just chip or bend.) Particularly for digital signage applications having a cover glass shatter rather than just break could be a consumer issue.

Tempered glass can not be used for LCDs due to the pattern of birefringence the tempering leaves in the glass. Birefringence is a polarization dependent optical effect that would interact with the polarized light coming from an LCD. An LCD viewed through thermally tempered glass would appear to have a mottled image. Coating the glass with an even harder substance is an option. But here again, the product would have optical issues. As far as I know, every material that you could coat the glass with has a higher index of refraction than glass. This would result in increased surface reflections.

Why not use Plastic?
Years ago, I read an article title “The Dream of an All-Plastic Car”. The article was published in ine of the chemical industry magazines and covered opportunities such as plastic bodies and plastic windows. However, it turns out that the dream of an all plastic car was the chemical companies’ dream, not the auto makers or consumers. There were a few models made with plastic bodies and one made with one plastic window (the side window on the back of a CRX. However, plastic does not age very well in the sun and has very very limited abrasion resistance. The auto industry did largely move to plastic headlamp covers. However, these often turn cloudy after a few years and the the cloudy appearance would not be acceptable for a window or auto-body.

Plastic does not have nearly the hardness of glass and can’t handle even moderate levels of abrasion without a grossly diminished finish. It also degrades under UV.

Plate Glass for Digital Signage
Currently, in the digital signage industry, most use plate glass to protect their signage where it is required (anywhere the public can actually touch the screen). UL provides a minimal level of guidance as to the thickness with its ball drop test. Meeting UL 6950 requires about 2mm of chemically strengthened glass or about 2.5mm of plate glass. Other architectural or automotive standards (ASTM or SAE) or practices may be applied leading to thicker glass and site architects my specify vandal-proof or even bullet-proof levels of protection. Thicknesses in actual use in the industry range up to 13mm, frequently either bonded to the LCD or two separate pieces of glass laminated together. The lamination adds strength and also protects the public from broken pieces should he cover glass do break.

Conclusion
The UL standard is a strength standard rather than a dimensional one that buyers of digital signage can test for, non-destructively. It provides minimal protection. Other standards may come from the architectural community, the materials suppliers, or groups like the SAE that are used to dealing with glass safety. However, it would be beneficial if the digital signage industry were to agree internally on standards for both product and consumer protection.

Norm

What is the "Killer App" for Smart TV

Introduction

When IBM fist introduced its PC, Apple placed a full page ad in The Wall Street Journal saying that they were glad that this happened and how it would be great for the PC market. Of course it was great; but after having the market virtually to itself, Apple's own share of the PC market shrank well below 5% before rebounding on Apple's strength in other products. As with any technology, radical change is needed to keep the technology fresh. But radical change is frequently a great hazard to the major incumbents.

The first computers were behemoths. They were physically large and had very large, in many cases water cooled, specialized processors. Later, came both smaller computers (mini's and PCs) as well as even larger supercomputers. The supercomputers initially had specialized central processing units (CPUs) as well but eventually the high performance computing (HPC) world figured out that they could make very effective supercomputers using arrays of generalized processors, such as what was found in PCs, acting in parallel. Indeed, many of the more interesting problems that supercomputers were destined to work on were more appropriately addressed by parallel processing than by one large, supercharged, CPU. This contributed to the decline of companies like Cray and the rise of Intel in the HPC world.

Eventually the idea of parallel process was carried a step further. The generalized PC CPUs in supercomputers began to be replaced by Graphics processing units (GPU's) that are themselves inherently parallel. Most supercomputers being built today are being powered by GPUs rather than CPUs and the world's fastest is being created with GPUs. As the use of GPUs beyond the basic application of image rendering has grown, so too has the population of programmers familiar with GPU programing.

And how does this relate to television??? With the arrival of LCDs and digital images came digital image processing. There is a significant amount of computing going on in the background of your LCD in order to deliver the image that you see. In addition, TVs have gotten "Smart" with the introduction of such features as voice, facial, and gesture recognition requiring modern TVs to significantly boost their computing power. Although TVs remain as one of the most price constrained of any consumer electronics platform, they are also one of the most given to being sold based on specs. TV brands have done battle based on brightness, color fidelity, contrast, thinness, etc. What would happen if the industry borrowed a page from the computer world and started competing based on processor speed. Probably not much unless there were some application to drive it.

The Killer App
MiniTel was recently switched off. For those of you that are unaware of MiniTel, it was the first internet-like service. It was the brainchild of France Telecom and was up and running in the mid 1980's before there was an internet. I saw MiniTel and thought it was a useful but fairly limited service, which it was. However, what I failed to see was how such a service could blossom going from a limited and centralized service to the inherently decentralized internet of today. So, given my admitted limited abilities to comprehend technological advancement, here are some applications that I think will drive smart TV sales in the future.

Social Interaction
As TVs became cheap and the nation went from one TV per household to one TV per room, watching television went from a family affair to a solitary activity. Indeed, the whole social media revolution has bypassed TV for the time being. As sets gain in computing power and input devices are added (cameras and microphones) TV sets could adopt some of the same applications as in the mobile phone market. Also, similar to what is going on in social media in general, user generated content could become a significant part of what gets viewed.

2D to 3D Upconversion
At some point 3D will become common and even usual. At that point, most content will still be in 2D and with the market for 3D content growing, there will be, or is now, a market to convert 2D content to 3D. As with colorization of black and white films, the initial results may be less than spectacular, but as an audience grows up with an expectation of 3D availability someone will satisfy that need.

Home Automation
Some years ago I was involved in fundraising for a start-up called Toprover. I was able to get Mr. Jobs to look at it (he apparently visited their web site several times) but he apparently did not bite. What Toprover had was a comprehensive home automation program and device. It actually made use of large HDTV screens with a comprehensive control panel and had enough embedded computing power to do all sorts of useful things around the home. Like 3D, I consider home automation to be an inevitability. I think that control modules, device intelligence and communications are cheap and easy enough that now could be the time.

Voice and Gesture Control
Another inevitable technology, however, it can be more than an improvement to the remote control. As with Pandora, increased feedback from the user could tailor suggested content, switch the image to different perspectives, maybe even customize general content in some way. This could include changing the visual perspective on image content, customizing the news to skip uninteresting matters or provide more detail on others, or customized weather reports for the particular micro-climate in your neighborhood. As with most things involved with display technology, the innovations are not as likely to be involved with an improved display as with improved human interaction.

Conclusion
This article began with a longish introduction, mostly about the development of computing power, particularly the development of parallel processors useful in image processing and now other applications. What followed was some speculation about what sort of applications this computing power could be put to use on, most of which I consider inevitable. However, this is coming from an observe that did not see the seeds to the internet in Minitel. I have, however, had my share of prognostications including the rapid increase in pixel count for mobile devices. ("The case for a flexible touch panel keyboard", in Touch Panel, Sep 20, 2009) No doubt at some point the rise in available processing power will enable holographic 3D; but no time soon. However, there undoubtedly will be other apps that are completely new that few can envision now.

From the movie "The Meaning of Life"
Exec #1: Item six on the agenda: "The Meaning of Life" Now uh, Harry, you've had some thoughts on this.
Exec #2: Yeah, I've had a team working on this over the past few weeks, and what we've come up with can be reduced to two fundamental concepts. One: People aren't wearing enough hats. Two: Matter is energy. In the universe there are many energy fields which we cannot normally perceive...
... However, this is rarely achieved owing to man's unique ability to be distracted from spiritual matters by everyday trivia.
Exec #3: What was that about hats again?

The image above is from the movie "The Ring" about a videotape that will kill you if you watch it.

A Projection Avatar Lands at La Guadia

At La Guardia, a Smiling Helper Materializes, Digitally

" Marie is an avatar, a life-size image of a woman digitally broadcast from a projector onto an inch-thick glass screen coated with a special film, said Luis Vega, 39, the vice president of Parabit Systems, the company that built Marie. The device uses motion sensors to prompt Marie’s 90-second script whenever anyone comes within 30 feet of her. Marie stopped many travelers in their tracks on Wednesday morning, and some walked a circle around her to see how she worked. Others took photos. “I thought it was really a person at first glance,” said Alex Reiss, 21...."

Of course, the image is flat, and it is restricted to whatever shape the glass cut-out is (so the person filmed for the content must remain still) but it does look quite a bit like the holographic images from the "Star Wars" movies. Being able to see behind the image gives the illusion of 3D. One was on display at Digital Signage Expo and attracted a lot of attention.

Airports were early users of public electronic information displays, even before the flat panel era. It is not surprising that they would adopt this unique but somewhat expensive but striking technology. Projection type displays are increasingly "off the radar" in many markets. However, that may be due to not having quite the right product as projection can still provide great value and unique form factors.

The placing of this particular technology at the airports around New York give some indication of just how large the digital signage market can be. In-spite of the substantial price, the avatar does not replace a person as having a person there full time would be unaffordable. This bit of digital signage provides a new service at an affordable cost even at tens of thousands. Simpler signage can be envisioned at virtually every sort of commercial outlet even down to the smallest mom & pop.

Norm