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Advancing Cluster Technology

If European automotive customers are any indication, then there may be a greater acceptance of electronics-based gages in the not-too-distant future. This could have some major effects on packaging, manufacturing, and costs—good ones.

As part of its acquisition of the automotive electronics business of French company Sagem SA last year, Johnson Controls, Inc. (JCI; Plymouth, MI) not only achieved stronger business relationships with companies including Peugeot and Renault (qui), but it increased expertise in the areas of software and systems engineering for electronics and electrical systems, including body and engine controller, multimedia and telematics systems, instrument clusters, and information displays. And the automotive interiors specialist also gained some new employees, including Loick Griselain, who is now the company's business manager, Body Electronics. The term "body" notwithstanding, one of the things that he's most interested in is actually something that many would consider to be "interior" electronics. Proffering instrument clusters in each hand, Griselain points out that one is much bigger than the other. That's because one is conventional: it uses light bulbs to illuminate the speedometer, tachometer, etc. But the other uses light-emitting diodes. Consequently, the package is much thinner.

An additional advantage relates to manufacturing. That is, in the approach that JCI is trying to convince automakers to adopt is advantageous, there is a single part used to direct the light: a two-shot plastic injection molded piece. In the conventional approach, there are, Griselain explains, a number of mechanical parts that are used to defuse and guide the light from a bulb to the dial. JCI's design is much simpler: a back cover, a PC board, light box, bezel, and lens. According to Griselain, with this new design, assembly time is reduced by a factor of three. Of course, it needs to be noted that it was necessary to modify the production process for the new approach. But with an improvement in operations that can be realized, this can probably be justified without too much difficulty.

 

Think Different

New approaches are fundamental to what Griselain and his colleagues are promoting. For example, he believes that liquid crystal diode (LCD) technology is advantageous for cluster assemblies, too. Yet he notes, that rather than going with LCDs, U.S. vehicle manufacturers, when looking for that bright blue-green color, utilize vacuum fluorescent displays. Which are (1) more expensive than LCDs and (2) result in a thicker assembly. To be fair, however, he notes that as few as two or three years ago, LCD technology wasn't sufficiently mature for automotive applications. However, he goes on to say that when you look at some European vehicles—from Volkswagen, Mercedes, Renault, PSA—there are plenty of LCDs in clusters. When they want to do something different in European applications, they opt for the vacuum fluorescent display, which is approximately opposite of the approach in the U.S.

Griselain admits that visually, the LCD doesn't provide the same contrast the vacuum fluorescent approach does, and that American consumers tend to be more demanding than their European counterparts in this regard. But he adds that there are electroluminscent films that can bump up the contrast to meet these demands.

But what about the things that the customer can't see? One of the ideas that is gaining greater currency in the auto industry is that it is good to have differentiation where there is customer interface, and only there. For example, does the customer care in the least bit whether what's behind the instrument panel is unique to a particular vehicle? Probably not. What Griselain is interested in is providing a complete range of clusters for various vehicles (or at least trim levels for a single vehicle) based on a single architecture. That is, the faces can be modified, but what's behind them can be standardized. What's more, as there is greater electronics content in gage clusters, there is a concomitant increase in the amount of software associated with the gages. By achieving commonality, software development can be minimized. And, of course, there are the economies of scale that are gained by making hundreds of thousands of the same thing. In fact, Griselain believes that it may be possible to develop a single motherboard (after all, he's thinking in the context of such things as thin-film transistor (TFT) and organic LED or electro luminescent technology, not bulb-in-a-socket) that could be used by more than one automaker so that there are actually millions of them made, which would significantly drive down the price.

And remember: The consumer won't even see the difference.