Glass is Hard Pt III

Two extreme stories regarding glass chemistry. In the first, after bringing in a new furnace (the furnace had been torn down and rebuilt with new brick, this must be done periodically) the glass coming out of the furnace was foaming. It was full of bubbles. After more than a month of researching the problem, someone though to ask the old melter (the person in charge of running that furnace) about the problem; he had retired between the last rebuild and this one. He had no idea about what to do, but he did comment that whenever he brought in a new furnace, he always through a silver dollar in for luck. In the second story, one of the company’s CRT making glass furnaces suddenly started have well above average product breakage at the customer. Coincidentally, they also had a problem with their glass molds; molds that were supposed to last for weeks were lasting only days.

The first story was told to me and may be apocryphal, the second, I actually witnessed and was a participant in reaching resolution. They were both essentially the same problem. In the first story, it can be hard to appreciate, but commonly parts per billion of some element or another, can have a large effect in stabilizing or processing the glass. Much of glass development is taken up not with developing new glass chemistries but in determining how a glass will react with the impurities it picks up from the furnace. Parts per billion, below the resolution limit of most x-ray machines commonly used for measuring glass chemistry, can have a determining effect on the glass suitability for a particular application. In the second story, one of the recouperators, the part of a glass furnace that captures the heat and sends it back to the furnace, had collapsed and the furnace was being fired with just one recouperator. Although the glass chemistry as was closely monitored before and after the collapse, the glass chemistry measurements usually do not include one of the most important elements, Oxygen. When the recouperator collapsed the melter changed the way he fired the furnace with changed the oxidation state of the glass. The glass chemistry before and after the change was the same but no one was looking at the oxygen.

Fusion glass, used as LCD substrates, is made in platinum lined furnaces to minimize an impact refractory contamination can have. However, raw materials can still have a huge impact. For most "dirt is dirt and sand is sand" however for glass and ceramic making, many times, even when the mining location is changed within the same mine, it means requalifying the process.

LCD v. OLED TV

When no one had heard of an LCD, the companies developing the technology, RCA and Westinghouse, were both TV makers and the objective was to build a TV with the technology. However, we would still not LCD TVs today if it were not for the notebook computer providing a product that could not be made without it. The notebook provided a high valued product that could afford the LCD price tag ($1000 for a 10.4") while the industry cost reduced and perfected the product for consumer TV. Actually, the path was notebook, then monitors, then TV.

The fact that the public has gotten used to the idea of a flat panel does not make it easier for OLED technology, it makes it harder in that their is already a product there that is very cheap and its performance is more than fine. Even though OLED visual performance will be better, no one is unhappy with current LCD performance.

What will make OLED technology and what will eventually make an OLED TV commonplace will not be the immediate application of the technology to TV but an application not currently served by LCD; most probably a new product or new form factor that takes advantage of OLED's ability to be made as a flexible or fracture resistant display.... Dick Tracy's watch or some sort of wearable device. Once volume is generated form this new application, OLED can come down in price and be a TV.

4K & Osborne Effect

Once again, the movie makers are giving advice to the TV industry about how to run the TV business. Taking the theatrical cinema folk's advice about home TV, even home theater is why the TV industry spent so much time hyping 3D well before its time. A basic premise in the article is incorrect regarding TV sizes. In general, the public had found its way to sitting at the retina limiting distance for standard definition TV. In the transition to HDTV, with twice as many scan lines, they had to either get a set that is twice as tall or sit half the distance to still be at the retina limiting distance. Instead, the public mainly bought 32" wide screens that are exactly the same height as a 27" square screen and sat at the same distance. Since the transition, the average size LCD TV has crept up from a 32W to a 38W. The public is still not taking advantage of HDTV resolution, let alone doubling it again.

Normally, I would not be one to criticize the industry regarding anything done to increase profitability in what is largely a profitless business. However, sometimes the things that are done to increase ASPs actually discourage sales. In the early 1990's TV set sales were depressed by talk of HDTV. The discussion in the press about the new standard lead people to believe that HDTV was just around the corner and many postponed buying a TV set thinking that they should wait and get an HDTV. Talk of a new standard frequently discourages sales of current models. This is known as Osborn effect for Adam Osborne driving his own company out of business talking about the next model Osborne Computer, that wasn't ready, and consequently not being able to sell the current one. I believe that 3D had a similarly chilling effect. And now comes 4K.

As I said in a previous post, 4K will be a great boon the digital signage. No doubt it will garner some consumer sales as well. However the net effect on total consumer sales dollars will be minimal if it is positive at all. Currently, widespread realease of 5G smartphones is not expected until 2020. However, whith smartphone prices climbing into the $1000 range, sales of 4G smartphones during 2019 may be impacted by consumers postponing purchases to get the new 5G technology.

What Could it Be

Oft times, when someone spots a trend, they offer a solution as if it were the only reason for the trend. On many occasions, the offered solution has little do do with causing the trend but is either a result of some other underlying factor or is auto-correlated with the real cause. Medical studies are frequently guilty of this. someone announces that "A" lifestyle is correlated with mortality from "B" disease where "A" lifestyle is also correlated with poverty which means you are more likely to die (particularly if you do not have healthcare) from any disease.

I say this as a prelude to some stark data. It seems that in spite of the crash of "08" and the subsequent "Great Recession", job offerings in digital signage have quadrupled over the last four years. Further, there seems to have been o offerings prior to '06.

In truth, people have been using video displays as signage since there have been video displays. As I relate in a number of previous posts, the amount of "unaccounted" TVs, TVs sold in the US but not showing up in the sets per household numbers were always in the millions per year. Some of this was surveyed consumers loosing track of just how many TVs they owned, but most of the number were TVs converted to advertising or other commercial purposes. So the start of the employment numbers for "digital signage" was just the term coming into usage, not that there was no employment prior to '06.

The growth of the employment number in large part relates to the growth in the use of the term. However, much of that growth was probably expended by 2010 or 2011. At that time rather than the growth in employment offers flattening, it seems to have accelerated. Of course the offered graph charts job postings mentioning "digital signage" as a percent of all postings and some part of that growth would be do to a lack of jobs in other areas. But, even considering all of the other factors, that chart is fairly stunning.

After thinking about it for six months, a good friend of mind in the display industry decided that in time, digital signage could be as large as TV in terms of total screen area. It may never happen and it will certainly not happen soon but a casual reading of this chart leads me to believe that employment in the industry is not only trending upwards but accelerating upwards.

4K

My comment on 4K can be found on the LinkedIn Digital Signage Expo comment thread here. Basically, I make the argument that since Americans generally do not sit close enough (or have a large enough screen) to get the full benefit of HDTV, increasing the resolution to 4K does not matter much. But it will matter a whole lot to the digital signage market.

Voice v. Touch

In today's CNET coverage of CES, Intel VP Mooly Eden is forecasting that voice recognition will make touch obsolete. Of course for conversion to voice recognition to be absolute, it must do something that even most human brains can't do, understand everyone's accent. It must also be able to pick out a particular voice among the ambient din. But of course, voice recognition is computationally intensive where touch isn't.

As touch has not completely replaced keyboards, voice recognition will find its place (or places), but it will be mostly to augment human interfaces or provide a natural interface where touch is not practical.

Digital TV Profesionals Debate on Gun Safety.

Over the holidays there has been an ongoing discussion on the "Digital TV Professionals" LinkedIn site regarding the school shootings in Connecticut. Below is my response to one comment that we should not be having that debate there.

In response to Graham, if the forum were continually about gun safety, I would agree with you. However, any venue can serve as a forum for such exceptional events. Further, the violence is not without a TV connection. Long ago, the US congress decided that TV was part of the problem and required that US TV sets contain a "V chip" (V for violence) to enable parents to block violent content from children. In any forthcoming debate regarding new gun legislation, I expect that the role of TV, video games in particular, will come up again. Like it or not, we as technical professionals can not divorce ourselves from the environment and discuss only technical issues outside of any social context. Whether "guns kill people" or "people kill People," the people kill people advocates will likely point to TV.

Glass is Hard for Digital Signage II

Pyrex is a familiar name; what is it. To the technical folk at Corning, if you were discussing Pyrex, you were discussing alumino-borosilicate glass. It had a relatively high melting temperature and relatively low coefficient of thermal expansion (CTE). If you were discussing Pyrex with the marketing people, Pyrex® was a trade name that could be applied to anything. Since Corning sold its consumer products group, Pyrex has taken on more of the latter definition with tempered soda-lime glass being used in bakeware instead of boro-silicate. As the article states, the Pyrex you can buy today is “Not your grandmother’s Pyrex”.

Until the mid 1990’s all LCDs were made with Corning 7059 glass. “7059” was one of the compositions out of the Corning catalogue, the “Blue Pages.” Like the technical reference to Pyrex, 7059 meant a very specific composition. The Blue pages, only about a dozen copies ever existed, usually specified the type of furnace the glass was melted in and occasionally how the furnace was fired. Glasses need to matched to specific furnace refractories and even in the same furnace, changing the way you fired the furnace may give a different end composition and will give a different oxidation state of the glass… a different glass.

LCD substrates were manufactured exclusively on 7059 substrate not because of its composition or particular performance properties but because 7059 formed well on Corning’s fusion draw which made glass with virtually perfect flatness. Although it did not contain any group 1 elements (semiconductor poisons), 7059 had a number of drawbacks. Like most glasses, it formed a bit frothy and had to be compacted before use less the dimensions changed during the high temperature LCD processing. One of its other drawbacks was the high amount of arsenic contained in the glass. Arsenic is one of the elements that get added to glass to increase its formability and 7059 had a lot of it as the fusion process was extremely demanding. 7059 was replaced by 1737 and then by 1734, there was no particular order or logic behind the assignment numbering of glass compositions. Of course all of the newer glasses have names rather than numbers and many of the drawbacks have been addressed.

Having a name rather than a number does not mean that a technical glassmaker can or would ship anything or allow glass composition or processes to vary outside of established norms. Indeed it takes years to develop a new glass composition and depending on the element, parts per billion can radically impact its performance and fit for use. On occasion for CRTs, days worth of glass production were thrown out for parts per billion of Fluorine (a phosphor poison).

Although users of digital signage do not need to be concerned with chemical interactions, some knowledge of glass chemistry would be useful, particularly in selecting a cover glass, if one is required. In deciding between float vs. chemically strengthened, bonded vs. not, different selections will give different result in terms of cost, optical performance, fracture resistance, and what hazard is presented by the broken pieces should a fracture occur. The best advice is to know what you want, are getting, and to have a known supply chain that you trust.