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.

Optical Interconnects

Some years ago, Gene Amdahl was mounting a second startup. His first, Amdahl Computer was reasonably successful and subsequently sold to Fujitsu. The second startup was called Trilogy, it was an effort to build macro-scale processors that occupied an entire silicon wafer rather than just a chip. Though Trilogy came and went, it was a big deal at the time. The reason why the company is now just a historical footnote is that they ran into an insurmountable technology issue. They had no way to package the wafer. Specifically there was no way to get signal from one side of the wafer to the other. At the time, optical communications technology was still in its infancy. Trilogy approached Corning about developing an optical package but, of course, it was well beyond the capability of the optical technology as well.

Over a decade later, the issue came up again. As processor chips became denser, not only clock skew but interconnect densities started to become a problem, there was just not enough linear space at the edge to keep up with larger and more complex chips. Again, the obvious solution was to move to optical I/O. After another decade plus period of development, IBM has announced that the technology is ready to go. What this means is a few things. First, Moore’s Law gets another one of those needed breakthrough’s to keep it on-track. Second, with chips communicating optically, it is likely that you will now star seeing optical cabling inside computing devices rather than just a T3 fiber line leading to the building where they are housed. Third, rather than fiber reaching into the home (FTTH) or premises, you might see optical pathways directly from the device reaching out to the network.

In the optical networking world, there is a concept called “transparency” keeping the signal optical for a long as possible. Before the development of optical amplifiers, optical signals had to be periodically converted to electronics and regenerated as an optical signal. Given the processing and rise time of the electronics, it was much like flying a plane across the country but have to land every few miles and change planes. Transparency meant that the plane no longer had to land until it was near its destination. Optical I/O, optical output from computing devices may mean that the optical signal will eventually no longer have to drive to the local airport to catch its plane but can take off from right inside your PC. The results will be data rates that make today’s connections look like dial up. This scenario is probably another decade or so away, but an important threshold has been crossed.

This may also have some tendency to roll back the current "mobility boom" in favor of wired connections. Although wired connections tend to have inherently more bandwith than wireless, the wireless industry has been quite clever regarding signal processing and compressing more and more data into the spectrum available. Transparency right up to the processor may be more than can be matched by increased data compression presuming there is some application that could make use of it.

More is Better II (more of the same)

An old joke…. A man sees another man standing under a streetlight staring forlornly at the ground. The first man asks, “What’s wrong”? The second responds, “I dropped my car keys and can’t find them.” The first man looks at the pavement, clean and uncluttered, no sign of the keys. He asks the second man, “Are you sure you dropped them here?” The second man responds, “No I dropped them over there”, pointing off in the darkness. The first man, confused, asks, “Then why are you looking here?” The second man responds, “The light is better here.” (Image from Monk Wisdom.)

The joke is an illumination of the sometimes absurdity of looking for answers in a place of convenience rather than where you are most likely to find them. I once worked on a product, an optical film that had severe manufacturing issues. Unfortunately the work group was arranged so that all of the chemists were on the east coast where the factory was located and all of the optics expertise was on the west coast. The factory continued to look for a chemical solution to what proved to be an optical issue until the business was closed, a possible optical solution waiting, untried.

The LCD and TV industries do not have fatal issues keeping the product from the market, but the industries do suffer from a lack of innovation. Tim Cook’s recent pronouncement, “When I go into my living room and turn on the TV, I feel like I have gone backwards in time by 20 to 30 years” refers to a product that has some considerable staleness. If you follow the industry, there has been no lack of innovation, but much of it has been as effective as looking under a random streetlight instead of looking at the issues. Indeed, Tim Cook’s own company is guilty of this. In a previous posting, “More is Better”, I refer to the continued growth in pixel count in mobile devices when they obviously have severe sunlight viewability problems. Although a shortage of pixels was a real impediment to running complex apps (Graff Spee) for mobile devices, that seems to be a solved problem as pixel densities exceed human eye resolution.

In TV there have been even more innovations: ever improved image processing algorithms, “Connected TV,” “Smart TV”, 3D, and as if the TV also suffered from a pixel deficit 4K. Raymond Soneira deals with the efficacy of the 4K set quite succinctly in “Your existing HDTV is already a true 'Retina Display' ” . 3D seems to have arrived ahead of its time. “Connected TV” and “Smart TV” seem to be getting some yawns from Apple that, if Mr. Cook is to be taken seriously, has a mind to upend those developments. As to the algorithms, every digital manipulation of the image leaves its own set of digital artifacts. Particularly, as now when people are watching both digital and analog content, the digital manipulation of faces can leave a flat and cartoonish image with the wrong content source. Further the delay caused by the image manipulation can leave the picture out of synch with the sound if the sound source is not the TV itself. Interestingly, on higher end sets, they frequently have a gaming mode where you can turn off the image manipulation to keep the delay from disrupting your game. In many cases, video content looks better in gaming mode as well.

If you look historically at what innovations in LCD and TV have and have not made a difference, there is something of a pattern. In CRT real improvements were made with improved design: Trinitron and Black matrix, improved materials: invar shadow masks, black (36% transmission glass), new sources: cable and the vcr, and an improved usage model: home theater. There were also, of course more minor tweaks in design and materials as well as such things as Picture in Picture (PIP) the came and went. In LCD there was improved design: IPS and overdrive, improved materials: BEF, LED backlights and the optical rubbing that enabled multi domain, improved usage models: touch and going to wide screen, and any number of other innovations that have yet to leave a substantial permanent mark. Although there are occasionally electronic manipulations that prove to be indispensable such as overdrive, the big changes are frequently the introduction of new materials that materially change the optics of the device.

The TV may be in for a round of innovation as Apple threatens to fundamentally re-think the TV usage model. If Apple follows true to form, they will certainly push the technologies but will not hinge their new product on fundamentally new technology or more pedestrian approaches such as improved software. In Digital Signage, there is substantial room for innovation as well. Though it is still common for new implementers of Digital Signage to use TVs, the design requirements are different. Indeed, even for purpose built Digital signage screens, many of the design trade-offs embodied in current LCD production are optimize around the TV application but may not fit well with the varying environments and applications of Digital Signage. A re-thinking of digital signage design may be in order and some of that re-thinking may find its way into the general TV market as well. Much of this may be connected with the optics and materials used in the display rather than just the electronics.

Of the more prominent hiccups with the iPhone 5, two of the three (the choice of the sapphire lens cover and the anodized aluminum case) involved some new materials experimentation. The original choice of Gorilla Glass, is a materials experiment that went well; it was helped by the glass expertise of those familiar with that materials system. The challenges of mobile devices are different from the challenges digital signage but the idea of looking for a solution in the materials may be common. This does not mean waiting for IGZO or large size OLED technology to come down in price.

The Antique in the Livingroom

Tim Cook, “When I go into my living room and turn on the TV, I feel like I have gone backwards in time by 20 to 30 years."

Isn’t it interesting that while a phone is principally an audio device, it is virtually impossible to find a cell phone without a built in camera; whilst a TV is a video device but does not have a built in camera? As an audio device, the phone has become a primary tool for selling music. As a mobile internet connection, it has other uses but I think most of the revenue is in music sales. Although there are other media, the TV is the primary tool not only for selling video but everything else. Much of the rumor about why the rumored Apple TV set has yet to make an appearance surrounds resistance from the video content owners from doing a deal on Apple’s terms.

When Apple’s CEO, Mr. Cook, refereed to stepping back in time 20-30 years when he watches TV, he probably did not mean the screen (there is much speculation that although an Apple TV set will be state of the art, it will state of the art for current screen technology). Mr. Cook could have been referring to the lack of interactivity. But he may have been referring to the entire usage model including the content. Not just the videos, but the way the TV is used as a marketing platform. Much of apple’s business in connection with the iPhone revolves around purchased content. The ad-supported content market is much bigger. Certainly, the counter to a new Apple TV set oriented around purchased content would be one that could more generally serve as an advertising platform as the current TV set does but with a more net centric marketing approach. Although Apple may launch a curve ball or two in the hardware of an apple branded TV set such as a new aspect ratio, the big surprise may not be in the hardware or the software for that matter but in the content generation, a new way for marketers to pitch their product interactively.