Design headache: How do you design to minimize the impact of display obsolescence?
Margery Conner - June 1, 2012
Designing with LCDs can be a challenge because of the lack of standardization among the different product offerings. While this is true to some extent for almost all electronic components, most have some degree of commonality in voltage levels, package types, or at least connectors. Not so with LCDs. Not with their dimensions or, most tellingly, their connectors. And don’t even think about second sourcing in most instances – suppliers want you to design in their products and then be captive.
Ken Stewart-Smith, who founded Tronicon Industries as an engineering design and services firm in 1998, has run into these LCD design challenges head on. He wrote in an email (all of Ken’s comments are in italics below):
“I have been designing a product for about a year that uses a 3.5″ LCD graphics display and touch screen. The display I was using was manufactured by Optrex which has been bought out by Kyocera. Kyocera, without notice has decided to drop many (all?) of Optrex’s parts including the display I was using, with zero stock and no opportunity for a last time buy. With production slated to start in a few months, this has damaged my credibility with my client, not to mention the cost or re-designing for another display.
In my search for a replacement, I discovered that no two display manufactures make pin/functional displays, resulting in a costly re-design.
Here is an example of 5 different 3.5″ displays from 5 different manufactures.
All have different connectors (number of pins and physical location)
All have different controller drivers
Most have different backlight drive requirements
All have different touch controllers
My first comment: It appears that Kyocera bought out Optrex to eliminate the competition, has no plans to keep manufacturing the Optrex displays and is leaving customers stranded by dropping lines without notice and not offering customers the opportunity for last time buys.
My second comment: Why are display manufactures so reluctant to standardize products? What makes it so difficult? How does one design to minimize the impact of display obsolescence?”
(PowerSource again) While I have heard grumblings over the years about the lack of standardization in LCDs, I had not realized that that there was virtually no second-sourcing of the displays. How can they get buy-in from major device manufacturers or the military?
Ken is a small businessman who wouldn’t have many direct connections with a large multinational company like Kyocera. In this case, an engineer’s best friend is usually the distributor, and I saw that Digi-Key, which has a dedicated group of applications engineers, represented both Kyocera and Optrex. I figured that Digi-Key would be a good place to start to get a fairly evenhanded overview of the situation – was Kyocera really planning on leaving Optrex customers high and dry?
(btw, when I bounced the idea off of Ken about bringing Digi-Key into the loop, he was enthusiastic: “My favorite distributor is Digikey due to the nature of work I do. Almost without failure, I am able to get parts overnight (at a very reasonable shipping cost) as I move along in the development cycle of new products. If I blow something up (rarely but it does happen - part of “smoke testing”) or I find out a part just won’t work, a replacement is quickly at hand.” So there you have it: An unsolicited distributor thumbs-up.)
Ken provided some notes from the Kyocera End of Life information to pass on to DigiKey :
Ken’s analysis was this: “The replacements are not compatible and in fact they are the equivalent of replacing sugar with salt in a cake recipe. Even if I were able to substitute the parts, no one has stock. But the yellow highlight is the clincher.”
I passed all this information on to Randall Restle, Digi-Key’s Director of Design Support Services. Randall took a few days to investigate, and came back with this:
“Products going end of life have forever been problematic. Some firms have “Sustaining Engineering” departments to handle product redesign issues required to keep a product in production. Of course, it’s technology’s continual advance that causes the bulk of obsolescence as evidenced by analog tape’s demise to digital memory and 5 volt devices slowly succumbing to lower voltage devices. The other major cause is an unsustainable (perhaps unprofitable) level of business for the supplier. Digi-Key does not know the basis of Kyocera’s decision but, unfortunately, product redesign is typically the only remedy…
“That said, Digi-Key carries one of the suggested replacements as a stock item (T-55343GD035JU-LW-AEN), and the other as a non-stocking item (T-51963GD035J-MLW-AGN). Although Digi-Key never carried the two EOL part numbers, one of our application engineers was able to obtain their spec sheets and compare them to Kyocera’s suggested replacements. The two EOL part numbers have specific areas designated for either a 3X4 or 4X3 touch switch area that was monitored by circuitry that was built into the 10-position flat flex cable that attached to the customer’s PCB. The suggested replacements on the other hand, do not have any incorporated touch switch matrix, and simply terminate in a 4-position flat flex cable with X+, X-, Y+, and y- resistive outputs. The suggested replacements are just that, suggested replacements. Not drop-in replacements. Some re-engineering will be required.”
Ken went into a bit more detail about just how much engineering he’d have to put in: “The recommended replacement will require additional engineering (hardware and software) and being a resistive vs capacitive type touch panel will a) be more difficult to seal against moisture and b) will only last about half as long as the unit it is replacing (wear). So as far as being a replacement, it just won’t do.”
Ken’s not naïve: He understands the business decisions of companies can result in product changes which are highly-inconvenient to some of their customers, and that standardization is often not in the LCD supplier’s competitive interests. He suggests, however, that in the interests of building customer confidence, connector standardization would be a good place to start: Something as simple as a 50 pin FFC/FPC connector would meet the majority or requirements.
Let’s hear from any readers out there that have experience in designing with LCDs and dealing with the lack of standards as well as lack of second sources. Ken asked an excellent question: How do you design to minimize the impact of display obsolescence?